Adding upstream version 2.6.1.upstream/2.6.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

135 files changed, 58244 insertions, 0 deletions

diff --git a/apt-pkg/CMakeLists.txt b/apt-pkg/CMakeLists.txt
new file mode 100644
index 0000000..d13aed9
--- /dev/null
+++ b/apt-pkg/CMakeLists.txt
@@ -0,0 +1,86 @@
+# Include apt-pkg directly, as some files have #include <system.h>
+include_directories(${PROJECT_BINARY_DIR}/include/apt-pkg)
+
+file(MAKE_DIRECTORY ${PROJECT_BINARY_DIR}/include/apt-pkg/)
+execute_process(COMMAND grep -v "^#" "${CMAKE_CURRENT_SOURCE_DIR}/tagfile-keys.list"
+		OUTPUT_FILE "${CMAKE_CURRENT_BINARY_DIR}/tagfile-keys.clean.list")
+execute_process(COMMAND ${TRIEHASH_EXECUTABLE}
+                        --ignore-case
+                         --header ${PROJECT_BINARY_DIR}/include/apt-pkg/tagfile-keys.h
+                         --code ${CMAKE_CURRENT_BINARY_DIR}/tagfile-keys.cc
+                         --enum-class
+                         --enum-name pkgTagSection::Key
+                         --function-name pkgTagHash
+                         --include "<apt-pkg/tagfile.h>"
+                         --include "<apt-pkg/header-is-private.h>"
+                         "${CMAKE_CURRENT_BINARY_DIR}/tagfile-keys.clean.list")
+set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS "tagfile-keys.list")
+set_source_files_properties("${CMAKE_CURRENT_BINARY_DIR}/tagfile-keys.cc" PROPERTIES COMPILE_DEFINITIONS APT_COMPILING_APT)
+
+
+# Set the version of the library
+execute_process(COMMAND awk -v ORS=. "/^\#define APT_PKG_M/ {print \$3}"
+                COMMAND sed "s/\\.\$//"
+                INPUT_FILE ${CMAKE_CURRENT_SOURCE_DIR}/contrib/macros.h
+                OUTPUT_VARIABLE MAJOR OUTPUT_STRIP_TRAILING_WHITESPACE)
+execute_process(COMMAND grep "^#define APT_PKG_RELEASE"
+                COMMAND cut -d " " -f 3
+                INPUT_FILE ${CMAKE_CURRENT_SOURCE_DIR}/contrib/macros.h
+                OUTPUT_VARIABLE MINOR OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+message(STATUS "Building libapt-pkg ${MAJOR} (release ${MINOR})")
+set(APT_PKG_MAJOR ${MAJOR} PARENT_SCOPE) # exporting for methods/CMakeLists.txt
+
+configure_file(apt-pkg.pc.in ${CMAKE_CURRENT_BINARY_DIR}/apt-pkg.pc @ONLY)
+
+# Definition of the C++ files used to build the library - note that this
+# is expanded at CMake time, so you have to rerun cmake if you add or remove
+# a file (you can just run cmake . in the build directory)
+file(GLOB_RECURSE library "*.cc"  "${CMAKE_CURRENT_BINARY_DIR}/tagfile-keys.cc")
+file(GLOB_RECURSE headers "*.h")
+
+# Create a library using the C++ files
+add_library(apt-pkg SHARED ${library})
+add_dependencies(apt-pkg apt-pkg-versionscript)
+# Link the library and set the SONAME
+target_include_directories(apt-pkg
+                           PRIVATE ${ZLIB_INCLUDE_DIRS}
+                                   ${BZIP2_INCLUDE_DIR}
+                                   ${LZMA_INCLUDE_DIRS}
+                                   ${LZ4_INCLUDE_DIRS}
+                                   $<$<BOOL:${ZSTD_FOUND}>:${ZSTD_INCLUDE_DIRS}>
+                                   $<$<BOOL:${UDEV_FOUND}>:${UDEV_INCLUDE_DIRS}>
+                                   $<$<BOOL:${SYSTEMD_FOUND}>:${SYSTEMD_INCLUDE_DIRS}>
+                                   ${ICONV_INCLUDE_DIRS}
+                                   $<$<BOOL:${GCRYPT_FOUND}>:${GCRYPT_INCLUDE_DIRS}>
+                                   $<$<BOOL:${XXHASH_FOUND}>:${XXHASH_INCLUDE_DIRS}>
+)
+
+target_link_libraries(apt-pkg
+                      PRIVATE -lutil ${CMAKE_DL_LIBS} ${RESOLV_LIBRARIES}
+                             ${CMAKE_THREAD_LIBS_INIT}
+                             ${ZLIB_LIBRARIES}
+                             ${BZIP2_LIBRARIES}
+                             ${LZMA_LIBRARIES}
+                             ${LZ4_LIBRARIES}
+                             $<$<BOOL:${ZSTD_FOUND}>:${ZSTD_LIBRARIES}>
+                             $<$<BOOL:${UDEV_FOUND}>:${UDEV_LIBRARIES}>
+                             $<$<BOOL:${SYSTEMD_FOUND}>:${SYSTEMD_LIBRARIES}>
+                             ${ICONV_LIBRARIES}
+                             $<$<BOOL:${GCRYPT_FOUND}>:${GCRYPT_LIBRARIES}>
+                             $<$<BOOL:${XXHASH_FOUND}>:${XXHASH_LIBRARIES}>
+)
+set_target_properties(apt-pkg PROPERTIES VERSION ${MAJOR}.${MINOR})
+set_target_properties(apt-pkg PROPERTIES SOVERSION ${MAJOR})
+set_target_properties(apt-pkg PROPERTIES CXX_VISIBILITY_PRESET hidden)
+add_version_script(apt-pkg)
+
+# Install the library and the header files
+install(TARGETS apt-pkg LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
+install(FILES ${headers} DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/apt-pkg)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/apt-pkg.pc DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+flatify(${PROJECT_BINARY_DIR}/include/apt-pkg/ "${headers}")
+
+if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
+  target_link_libraries(apt-pkg PUBLIC noprofile)
+endif()
diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
new file mode 100644
index 0000000..7df6483
--- /dev/null
+++ b/apt-pkg/acquire-item.cc
@@ -0,0 +1,4115 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Item - Item to acquire
+
+   Each item can download to exactly one file at a time. This means you
+   cannot create an item that fetches two uri's to two files at the same 
+   time. The pkgAcqIndex class creates a second class upon instantiation
+   to fetch the other index files because of this.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/acquire-worker.h>
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <ctime>
+#include <chrono>
+#include <iostream>
+#include <memory>
+#include <numeric>
+#include <random>
+#include <sstream>
+#include <string>
+#include <unordered_set>
+#include <vector>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+static std::string GetPartialFileName(std::string const &file)		/*{{{*/
+{
+   std::string DestFile = _config->FindDir("Dir::State::lists") + "partial/";
+   DestFile += file;
+   return DestFile;
+}
+									/*}}}*/
+static std::string GetPartialFileNameFromURI(std::string const &uri)	/*{{{*/
+{
+   return GetPartialFileName(URItoFileName(uri));
+}
+									/*}}}*/
+static std::string GetFinalFileNameFromURI(std::string const &uri)	/*{{{*/
+{
+   return _config->FindDir("Dir::State::lists") + URItoFileName(uri);
+}
+									/*}}}*/
+static std::string GetKeepCompressedFileName(std::string file, IndexTarget const &Target)/*{{{*/
+{
+   if (Target.KeepCompressed == false)
+      return file;
+
+   std::string const KeepCompressedAs = Target.Option(IndexTarget::KEEPCOMPRESSEDAS);
+   if (KeepCompressedAs.empty() == false)
+   {
+      std::string const ext = KeepCompressedAs.substr(0, KeepCompressedAs.find(' '));
+      if (ext != "uncompressed")
+	 file.append(".").append(ext);
+   }
+   return file;
+}
+									/*}}}*/
+static std::string GetMergeDiffsPatchFileName(std::string const &Final, std::string const &Patch)/*{{{*/
+{
+   // rred expects the patch as $FinalFile.ed.$patchname.gz
+   return Final + ".ed." + Patch + ".gz";
+}
+									/*}}}*/
+static std::string GetDiffsPatchFileName(std::string const &Final)	/*{{{*/
+{
+   // rred expects the patch as $FinalFile.ed
+   return Final + ".ed";
+}
+									/*}}}*/
+static std::string GetExistingFilename(std::string const &File)		/*{{{*/
+{
+   if (RealFileExists(File))
+      return File;
+   for (auto const &type : APT::Configuration::getCompressorExtensions())
+   {
+      std::string const Final = File + type;
+      if (RealFileExists(Final))
+	 return Final;
+   }
+   return "";
+}
+									/*}}}*/
+static std::string GetDiffIndexFileName(std::string const &Name)	/*{{{*/
+{
+   return Name + ".diff/Index";
+}
+									/*}}}*/
+static std::string GetDiffIndexURI(IndexTarget const &Target)		/*{{{*/
+{
+   return Target.URI + ".diff/Index";
+}
+									/*}}}*/
+
+static void ReportMirrorFailureToCentral(pkgAcquire::Item const &I, std::string const &FailCode, std::string const &Details)/*{{{*/
+{
+   // we only act if a mirror was used at all
+   if(I.UsedMirror.empty())
+      return;
+#if 0
+   std::cerr << "\nReportMirrorFailure: "
+	     << UsedMirror
+	     << " Uri: " << DescURI()
+	     << " FailCode: "
+	     << FailCode << std::endl;
+#endif
+   string const report = _config->Find("Methods::Mirror::ProblemReporting",
+				 LIBEXEC_DIR "/apt-report-mirror-failure");
+   if(!FileExists(report))
+      return;
+
+   std::vector<char const*> const Args = {
+      report.c_str(),
+      I.UsedMirror.c_str(),
+      I.DescURI().c_str(),
+      FailCode.c_str(),
+      Details.c_str(),
+      NULL
+   };
+
+   pid_t pid = ExecFork();
+   if(pid < 0)
+   {
+      _error->Error("ReportMirrorFailure Fork failed");
+      return;
+   }
+   else if(pid == 0)
+   {
+      execvp(Args[0], (char**)Args.data());
+      std::cerr << "Could not exec " << Args[0] << std::endl;
+      _exit(100);
+   }
+   if(!ExecWait(pid, "report-mirror-failure"))
+      _error->Warning("Couldn't report problem to '%s'", report.c_str());
+}
+									/*}}}*/
+
+static APT_NONNULL(2) bool MessageInsecureRepository(bool const isError, char const * const msg, std::string const &repo)/*{{{*/
+{
+   std::string m;
+   strprintf(m, msg, repo.c_str());
+   if (isError)
+   {
+      _error->Error("%s", m.c_str());
+      _error->Notice("%s", _("Updating from such a repository can't be done securely, and is therefore disabled by default."));
+   }
+   else
+   {
+      _error->Warning("%s", m.c_str());
+      _error->Notice("%s", _("Data from such a repository can't be authenticated and is therefore potentially dangerous to use."));
+   }
+   _error->Notice("%s", _("See apt-secure(8) manpage for repository creation and user configuration details."));
+   return false;
+}
+									/*}}}*/
+// AllowInsecureRepositories						/*{{{*/
+enum class InsecureType { UNSIGNED, WEAK, NORELEASE };
+static bool TargetIsAllowedToBe(IndexTarget const &Target, InsecureType const type)
+{
+   if (_config->FindB("Acquire::AllowInsecureRepositories"))
+      return true;
+
+   if (Target.OptionBool(IndexTarget::ALLOW_INSECURE))
+      return true;
+
+   switch (type)
+   {
+      case InsecureType::UNSIGNED: break;
+      case InsecureType::NORELEASE: break;
+      case InsecureType::WEAK:
+	 if (_config->FindB("Acquire::AllowWeakRepositories"))
+	    return true;
+	 if (Target.OptionBool(IndexTarget::ALLOW_WEAK))
+	    return true;
+	 break;
+   }
+   return false;
+}
+static bool APT_NONNULL(3, 4, 5) AllowInsecureRepositories(InsecureType const msg, std::string const &repo,
+      metaIndex const * const MetaIndexParser, pkgAcqMetaClearSig * const TransactionManager, pkgAcquire::Item * const I)
+{
+   // we skip weak downgrades as its unlikely that a repository gets really weaker –
+   // its more realistic that apt got pickier in a newer version
+   if (msg != InsecureType::WEAK)
+   {
+      std::string const FinalInRelease = TransactionManager->GetFinalFilename();
+      std::string const FinalReleasegpg = FinalInRelease.substr(0, FinalInRelease.length() - strlen("InRelease")) + "Release.gpg";
+      if (RealFileExists(FinalReleasegpg) || RealFileExists(FinalInRelease))
+      {
+	 char const * msgstr = nullptr;
+	 switch (msg)
+	 {
+	    case InsecureType::UNSIGNED: msgstr = _("The repository '%s' is no longer signed."); break;
+	    case InsecureType::NORELEASE: msgstr = _("The repository '%s' no longer has a Release file."); break;
+	    case InsecureType::WEAK: /* unreachable */ break;
+	 }
+	 if (_config->FindB("Acquire::AllowDowngradeToInsecureRepositories") ||
+	       TransactionManager->Target.OptionBool(IndexTarget::ALLOW_DOWNGRADE_TO_INSECURE))
+	 {
+	    // meh, the users wants to take risks (we still mark the packages
+	    // from this repository as unauthenticated)
+	    _error->Warning(msgstr, repo.c_str());
+	    _error->Warning(_("This is normally not allowed, but the option "
+		     "Acquire::AllowDowngradeToInsecureRepositories was "
+		     "given to override it."));
+	 } else {
+	    MessageInsecureRepository(true, msgstr, repo);
+	    TransactionManager->AbortTransaction();
+	    I->Status = pkgAcquire::Item::StatError;
+	    return false;
+	 }
+      }
+   }
+
+   if(MetaIndexParser->GetTrusted() == metaIndex::TRI_YES)
+      return true;
+
+   char const * msgstr = nullptr;
+   switch (msg)
+   {
+      case InsecureType::UNSIGNED: msgstr = _("The repository '%s' is not signed."); break;
+      case InsecureType::NORELEASE: msgstr = _("The repository '%s' does not have a Release file."); break;
+      case InsecureType::WEAK: msgstr = _("The repository '%s' provides only weak security information."); break;
+   }
+
+   if (TargetIsAllowedToBe(TransactionManager->Target, msg) == true)
+   {
+      MessageInsecureRepository(false, msgstr, repo);
+      return true;
+   }
+
+   MessageInsecureRepository(true, msgstr, repo);
+   TransactionManager->AbortTransaction();
+   I->Status = pkgAcquire::Item::StatError;
+   return false;
+}
+									/*}}}*/
+static HashStringList GetExpectedHashesFromFor(metaIndex * const Parser, std::string const &MetaKey)/*{{{*/
+{
+   if (Parser == NULL)
+      return HashStringList();
+   metaIndex::checkSum * const R = Parser->Lookup(MetaKey);
+   if (R == NULL)
+      return HashStringList();
+   return R->Hashes;
+}
+									/*}}}*/
+
+class pkgAcquire::Item::Private /*{{{*/
+{
+public:
+   struct AlternateURI
+   {
+      std::string URI;
+      std::unordered_map<std::string, std::string> changefields;
+      AlternateURI(std::string &&u, decltype(changefields) &&cf) : URI(u), changefields(cf) {}
+   };
+   std::list<AlternateURI> AlternativeURIs;
+   std::vector<std::string> BadAlternativeSites;
+   std::vector<std::string> PastRedirections;
+   std::unordered_map<std::string, std::string> CustomFields;
+   time_point FetchAfter = {};
+
+   Private()
+   {
+   }
+};
+									/*}}}*/
+
+// all ::HashesRequired and ::GetExpectedHashes implementations		/*{{{*/
+/* ::GetExpectedHashes is abstract and has to be implemented by all subclasses.
+   It is best to implement it as broadly as possible, while ::HashesRequired defaults
+   to true and should be as restrictive as possible for false cases. Note that if
+   a hash is returned by ::GetExpectedHashes it must match. Only if it doesn't
+   ::HashesRequired is called to evaluate if its okay to have no hashes. */
+APT_PURE bool pkgAcqTransactionItem::HashesRequired() const
+{
+   /* signed repositories obviously have a parser and good hashes.
+      unsigned repositories, too, as even if we can't trust them for security,
+      we can at least trust them for integrity of the download itself.
+      Only repositories without a Release file can (obviously) not have
+      hashes – and they are very uncommon and strongly discouraged */
+   if (TransactionManager->MetaIndexParser->GetLoadedSuccessfully() != metaIndex::TRI_YES)
+      return false;
+   if (TargetIsAllowedToBe(Target, InsecureType::WEAK))
+   {
+      /* If we allow weak hashes, we check that we have some (weak) and then
+         declare hashes not needed. That will tip us in the right direction
+	 as if hashes exist, they will be used, even if not required */
+      auto const hsl = GetExpectedHashes();
+      if (hsl.usable())
+	 return true;
+      if (hsl.empty() == false)
+	 return false;
+   }
+   return true;
+}
+HashStringList pkgAcqTransactionItem::GetExpectedHashes() const
+{
+   return GetExpectedHashesFor(GetMetaKey());
+}
+
+APT_PURE bool pkgAcqMetaBase::HashesRequired() const
+{
+   // Release and co have no hashes 'by design'.
+   return false;
+}
+HashStringList pkgAcqMetaBase::GetExpectedHashes() const
+{
+   return HashStringList();
+}
+
+APT_PURE bool pkgAcqIndexDiffs::HashesRequired() const
+{
+   /* We can't check hashes of rred result as we don't know what the
+      hash of the file will be. We just know the hash of the patch(es),
+      the hash of the file they will apply on and the hash of the resulting
+      file. */
+   if (State == StateFetchDiff)
+      return true;
+   return false;
+}
+HashStringList pkgAcqIndexDiffs::GetExpectedHashes() const
+{
+   if (State == StateFetchDiff)
+      return available_patches[0].download_hashes;
+   return HashStringList();
+}
+
+APT_PURE bool pkgAcqIndexMergeDiffs::HashesRequired() const
+{
+   /* @see #pkgAcqIndexDiffs::HashesRequired, with the difference that
+      we can check the rred result after all patches are applied as
+      we know the expected result rather than potentially apply more patches */
+   if (State == StateFetchDiff)
+      return true;
+   return State == StateApplyDiff;
+}
+HashStringList pkgAcqIndexMergeDiffs::GetExpectedHashes() const
+{
+   if (State == StateFetchDiff)
+      return patch.download_hashes;
+   else if (State == StateApplyDiff)
+      return GetExpectedHashesFor(Target.MetaKey);
+   return HashStringList();
+}
+
+APT_PURE bool pkgAcqArchive::HashesRequired() const
+{
+   return LocalSource == false;
+}
+HashStringList pkgAcqArchive::GetExpectedHashes() const
+{
+   // figured out while parsing the records
+   return ExpectedHashes;
+}
+
+APT_PURE bool pkgAcqFile::HashesRequired() const
+{
+   // supplied as parameter at creation time, so the caller decides
+   return ExpectedHashes.usable();
+}
+HashStringList pkgAcqFile::GetExpectedHashes() const
+{
+   return ExpectedHashes;
+}
+									/*}}}*/
+// Acquire::Item::QueueURI and specialisations from child classes	/*{{{*/
+bool pkgAcquire::Item::QueueURI(pkgAcquire::ItemDesc &Item)
+{
+   Owner->Enqueue(Item);
+   return true;
+}
+/* The idea here is that an item isn't queued if it exists on disk and the
+   transition manager was a hit as this means that the files it contains
+   the checksums for can't be updated either (or they are and we are asking
+   for a hashsum mismatch to happen which helps nobody) */
+bool pkgAcqTransactionItem::QueueURI(pkgAcquire::ItemDesc &Item)
+{
+   if (TransactionManager->State != TransactionStarted)
+   {
+      if (_config->FindB("Debug::Acquire::Transaction", false))
+	 std::clog << "Skip " << Target.URI << " as transaction was already dealt with!" << std::endl;
+      return false;
+   }
+   std::string const FinalFile = GetFinalFilename();
+   if (TransactionManager->IMSHit == true && FileExists(FinalFile) == true)
+   {
+      PartialFile = DestFile = FinalFile;
+      Status = StatDone;
+      return false;
+   }
+   // this ensures we rewrite only once and only the first step
+   auto const OldBaseURI = Target.Option(IndexTarget::BASE_URI);
+   if (OldBaseURI.empty() || APT::String::Startswith(Item.URI, OldBaseURI) == false)
+      return pkgAcquire::Item::QueueURI(Item);
+   // the given URI is our last resort
+   PushAlternativeURI(std::string(Item.URI), {}, false);
+   // If we got the InRelease file via a mirror, pick all indexes directly from this mirror, too
+   std::string SameMirrorURI;
+   if (TransactionManager->BaseURI.empty() == false && TransactionManager->UsedMirror.empty() == false &&
+       URI::SiteOnly(Item.URI) != URI::SiteOnly(TransactionManager->BaseURI))
+   {
+      auto ExtraPath = Item.URI.substr(OldBaseURI.length());
+      auto newURI = flCombine(TransactionManager->BaseURI, std::move(ExtraPath));
+      if (IsGoodAlternativeURI(newURI))
+      {
+	 SameMirrorURI = std::move(newURI);
+	 PushAlternativeURI(std::string(SameMirrorURI), {}, false);
+      }
+   }
+   // add URI and by-hash based on it
+   if (AcquireByHash())
+   {
+      // if we use the mirror transport, ask it for by-hash uris
+      // we need to stick to the same mirror only for non-unique filenames
+      auto const sameMirrorException = [&]() {
+	 if (Item.URI.find("mirror") == std::string::npos)
+	    return false;
+	 ::URI uri(Item.URI);
+	 return uri.Access == "mirror" || APT::String::Startswith(uri.Access, "mirror+") ||
+	    APT::String::Endswith(uri.Access, "+mirror") || uri.Access.find("+mirror+") != std::string::npos;
+      }();
+      if (sameMirrorException)
+	 SameMirrorURI.clear();
+      // now add the actual by-hash uris
+      auto const Expected = GetExpectedHashes();
+      auto const TargetHash = Expected.find(nullptr);
+      auto const PushByHashURI = [&](std::string U) {
+	 if (unlikely(TargetHash == nullptr))
+	    return false;
+	 auto const trailing_slash = U.find_last_of("/");
+	 if (unlikely(trailing_slash == std::string::npos))
+	    return false;
+	 auto byhashSuffix = "/by-hash/" + TargetHash->HashType() + "/" + TargetHash->HashValue();
+	 U.replace(trailing_slash, U.length() - trailing_slash, std::move(byhashSuffix));
+	 PushAlternativeURI(std::move(U), {}, false);
+	 return true;
+      };
+      PushByHashURI(Item.URI);
+      if (SameMirrorURI.empty() == false && PushByHashURI(SameMirrorURI) == false)
+	 SameMirrorURI.clear();
+   }
+   // the last URI added is the first one tried
+   if (unlikely(PopAlternativeURI(Item.URI) == false))
+      return false;
+   if (SameMirrorURI.empty() == false)
+   {
+      UsedMirror = TransactionManager->UsedMirror;
+      if (Item.Description.find(" ") != string::npos)
+	 Item.Description.replace(0, Item.Description.find(" "), UsedMirror);
+   }
+   return pkgAcquire::Item::QueueURI(Item);
+}
+/* The transition manager InRelease itself (or its older sisters-in-law
+   Release & Release.gpg) is always queued as this allows us to rerun gpgv
+   on it to verify that we aren't stalled with old files */
+bool pkgAcqMetaBase::QueueURI(pkgAcquire::ItemDesc &Item)
+{
+   return pkgAcquire::Item::QueueURI(Item);
+}
+/* the Diff/Index needs to queue also the up-to-date complete index file
+   to ensure that the list cleaner isn't eating it */
+bool pkgAcqDiffIndex::QueueURI(pkgAcquire::ItemDesc &Item)
+{
+   if (pkgAcqTransactionItem::QueueURI(Item) == true)
+      return true;
+   QueueOnIMSHit();
+   return false;
+}
+									/*}}}*/
+// Acquire::Item::GetFinalFilename and specialisations for child classes	/*{{{*/
+std::string pkgAcquire::Item::GetFinalFilename() const
+{
+   // Beware: Desc.URI is modified by redirections
+   return GetFinalFileNameFromURI(Desc.URI);
+}
+std::string pkgAcqDiffIndex::GetFinalFilename() const
+{
+   std::string const FinalFile = GetFinalFileNameFromURI(GetDiffIndexURI(Target));
+   // we don't want recompress, so lets keep whatever we got
+   if (CurrentCompressionExtension == "uncompressed")
+      return FinalFile;
+   return FinalFile + "." + CurrentCompressionExtension;
+}
+std::string pkgAcqIndex::GetFinalFilename() const
+{
+   std::string const FinalFile = GetFinalFileNameFromURI(Target.URI);
+   return GetKeepCompressedFileName(FinalFile, Target);
+}
+std::string pkgAcqMetaSig::GetFinalFilename() const
+{
+   return GetFinalFileNameFromURI(Target.URI);
+}
+std::string pkgAcqBaseIndex::GetFinalFilename() const
+{
+   return GetFinalFileNameFromURI(Target.URI);
+}
+std::string pkgAcqMetaBase::GetFinalFilename() const
+{
+   return GetFinalFileNameFromURI(Target.URI);
+}
+std::string pkgAcqArchive::GetFinalFilename() const
+{
+   return _config->FindDir("Dir::Cache::Archives") + flNotDir(StoreFilename);
+}
+									/*}}}*/
+// pkgAcqTransactionItem::GetMetaKey and specialisations for child classes	/*{{{*/
+std::string pkgAcqTransactionItem::GetMetaKey() const
+{
+   return Target.MetaKey;
+}
+std::string pkgAcqIndex::GetMetaKey() const
+{
+   if (Stage == STAGE_DECOMPRESS_AND_VERIFY || CurrentCompressionExtension == "uncompressed")
+      return Target.MetaKey;
+   return Target.MetaKey + "." + CurrentCompressionExtension;
+}
+std::string pkgAcqDiffIndex::GetMetaKey() const
+{
+   auto const metakey = GetDiffIndexFileName(Target.MetaKey);
+   if (CurrentCompressionExtension == "uncompressed")
+      return metakey;
+   return metakey + "." + CurrentCompressionExtension;
+}
+									/*}}}*/
+//pkgAcqTransactionItem::TransactionState and specialisations for child classes	/*{{{*/
+bool pkgAcqTransactionItem::TransactionState(TransactionStates const state)
+{
+   bool const Debug = _config->FindB("Debug::Acquire::Transaction", false);
+   switch(state)
+   {
+      case TransactionStarted: _error->Fatal("Item %s changed to invalid transaction start state!", Target.URI.c_str()); break;
+      case TransactionAbort:
+	 if(Debug == true)
+	    std::clog << "  Cancel: " << DestFile << std::endl;
+	 if (Status == pkgAcquire::Item::StatIdle)
+	 {
+	    Status = pkgAcquire::Item::StatDone;
+	    Dequeue();
+	 }
+	 break;
+      case TransactionCommit:
+	 if(PartialFile.empty() == false)
+	 {
+	    bool sameFile = (PartialFile == DestFile);
+	    // we use symlinks on IMS-Hit to avoid copies
+	    if (RealFileExists(DestFile))
+	    {
+	       struct stat Buf;
+	       if (lstat(PartialFile.c_str(), &Buf) != -1)
+	       {
+		  if (S_ISLNK(Buf.st_mode) && Buf.st_size > 0)
+		  {
+		     char partial[Buf.st_size + 1];
+		     ssize_t const sp = readlink(PartialFile.c_str(), partial, Buf.st_size);
+		     if (sp == -1)
+			_error->Errno("pkgAcqTransactionItem::TransactionState-sp", _("Failed to readlink %s"), PartialFile.c_str());
+		     else
+		     {
+			partial[sp] = '\0';
+			sameFile = (DestFile == partial);
+		     }
+		  }
+	       }
+	       else
+		  _error->Errno("pkgAcqTransactionItem::TransactionState-stat", _("Failed to stat %s"), PartialFile.c_str());
+	    }
+	    if (sameFile == false)
+	    {
+	       // ensure that even without lists-cleanup all compressions are nuked
+	       std::string FinalFile = GetFinalFileNameFromURI(Target.URI);
+	       if (FileExists(FinalFile))
+	       {
+		  if(Debug == true)
+		     std::clog << "rm " << FinalFile << " # " << DescURI() << std::endl;
+		  if (RemoveFile("TransactionStates-Cleanup", FinalFile) == false)
+		     return false;
+	       }
+	       for (auto const &ext: APT::Configuration::getCompressorExtensions())
+	       {
+		  auto const Final = FinalFile + ext;
+		  if (FileExists(Final))
+		  {
+		     if(Debug == true)
+			std::clog << "rm " << Final << " # " << DescURI() << std::endl;
+		     if (RemoveFile("TransactionStates-Cleanup", Final) == false)
+			return false;
+		  }
+	       }
+	       if(Debug == true)
+		  std::clog << "mv " << PartialFile << " -> "<< DestFile << " # " << DescURI() << std::endl;
+	       if (Rename(PartialFile, DestFile) == false)
+		  return false;
+	    }
+	    else if(Debug == true)
+	       std::clog << "keep " << PartialFile << " # " << DescURI() << std::endl;
+
+	 } else {
+	    if(Debug == true)
+	       std::clog << "rm " << DestFile << " # " << DescURI() << std::endl;
+	    if (RemoveFile("TransItem::TransactionCommit", DestFile) == false)
+	       return false;
+	 }
+	 break;
+   }
+   return true;
+}
+bool pkgAcqMetaBase::TransactionState(TransactionStates const state)
+{
+   // Do not remove InRelease on IMSHit of Release.gpg [yes, this is very edgecasey]
+   if (TransactionManager->IMSHit == false)
+      return pkgAcqTransactionItem::TransactionState(state);
+   return true;
+}
+bool pkgAcqIndex::TransactionState(TransactionStates const state)
+{
+   if (pkgAcqTransactionItem::TransactionState(state) == false)
+      return false;
+
+   switch (state)
+   {
+      case TransactionStarted: _error->Fatal("AcqIndex %s changed to invalid transaction start state!", Target.URI.c_str()); break;
+      case TransactionAbort:
+	 if (Stage == STAGE_DECOMPRESS_AND_VERIFY)
+	 {
+	    // keep the compressed file, but drop the decompressed
+	    EraseFileName.clear();
+	    if (PartialFile.empty() == false && flExtension(PartialFile) != CurrentCompressionExtension)
+	       RemoveFile("TransactionAbort", PartialFile);
+	 }
+	 break;
+      case TransactionCommit:
+	 if (EraseFileName.empty() == false)
+	    RemoveFile("AcqIndex::TransactionCommit", EraseFileName);
+	 break;
+   }
+   return true;
+}
+bool pkgAcqDiffIndex::TransactionState(TransactionStates const state)
+{
+   if (pkgAcqTransactionItem::TransactionState(state) == false)
+      return false;
+
+   switch (state)
+   {
+      case TransactionStarted: _error->Fatal("Item %s changed to invalid transaction start state!", Target.URI.c_str()); break;
+      case TransactionCommit:
+	 break;
+      case TransactionAbort:
+	 std::string const Partial = GetPartialFileNameFromURI(Target.URI);
+	 RemoveFile("TransactionAbort", Partial);
+	 break;
+   }
+
+   return true;
+}
+									/*}}}*/
+// pkgAcqTransactionItem::AcquireByHash and specialisations for child classes	/*{{{*/
+bool pkgAcqTransactionItem::AcquireByHash() const
+{
+   if (TransactionManager->MetaIndexParser == nullptr)
+      return false;
+   auto const useByHashConf = Target.Option(IndexTarget::BY_HASH);
+   if (useByHashConf == "force")
+      return true;
+   return StringToBool(useByHashConf) == true && TransactionManager->MetaIndexParser->GetSupportsAcquireByHash();
+}
+// pdiff patches have a unique name already, no need for by-hash
+bool pkgAcqIndexMergeDiffs::AcquireByHash() const
+{
+   return false;
+}
+bool pkgAcqIndexDiffs::AcquireByHash() const
+{
+   return false;
+}
+									/*}}}*/
+
+class APT_HIDDEN NoActionItem : public pkgAcquire::Item			/*{{{*/
+/* The sole purpose of this class is having an item which does nothing to
+   reach its done state to prevent cleanup deleting the mentioned file.
+   Handy in cases in which we know we have the file already, like IMS-Hits. */
+{
+   IndexTarget const Target;
+   public:
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI;};
+   virtual HashStringList GetExpectedHashes()  const APT_OVERRIDE {return HashStringList();};
+
+   NoActionItem(pkgAcquire * const Owner, IndexTarget const &Target) :
+      pkgAcquire::Item(Owner), Target(Target)
+   {
+      Status = StatDone;
+      DestFile = GetFinalFileNameFromURI(Target.URI);
+   }
+   NoActionItem(pkgAcquire * const Owner, IndexTarget const &Target, std::string const &FinalFile) :
+      pkgAcquire::Item(Owner), Target(Target)
+   {
+      Status = StatDone;
+      DestFile = FinalFile;
+   }
+};
+									/*}}}*/
+class APT_HIDDEN CleanupItem : public pkgAcqTransactionItem		/*{{{*/
+/* This class ensures that a file which was configured but isn't downloaded
+   for various reasons isn't kept in an old version in the lists directory.
+   In a way its the reverse of NoActionItem as it helps with removing files
+   even if the lists-cleanup is deactivated. */
+{
+   public:
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI;};
+   virtual HashStringList GetExpectedHashes()  const APT_OVERRIDE {return HashStringList();};
+
+   CleanupItem(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager, IndexTarget const &Target) :
+      pkgAcqTransactionItem(Owner, TransactionManager, Target)
+   {
+      Status = StatDone;
+      DestFile = GetFinalFileNameFromURI(Target.URI);
+   }
+   bool TransactionState(TransactionStates const state) APT_OVERRIDE
+   {
+      switch (state)
+      {
+	 case TransactionStarted:
+	    break;
+	 case TransactionAbort:
+	    break;
+	 case TransactionCommit:
+	    if (_config->FindB("Debug::Acquire::Transaction", false) == true)
+	       std::clog << "rm " << DestFile << " # " << DescURI() << std::endl;
+	    if (RemoveFile("TransItem::TransactionCommit", DestFile) == false)
+	       return false;
+	    break;
+      }
+      return true;
+   }
+};
+									/*}}}*/
+
+// Acquire::Item::Item - Constructor					/*{{{*/
+pkgAcquire::Item::Item(pkgAcquire * const owner) :
+   FileSize(0), PartialSize(0), ID(0), Complete(false), Local(false),
+    QueueCounter(0), ExpectedAdditionalItems(0), Retries(_config->FindI("Acquire::Retries", 3)), Owner(owner), d(new Private())
+{
+   Owner->Add(this);
+   Status = StatIdle;
+}
+									/*}}}*/
+// Acquire::Item::~Item - Destructor					/*{{{*/
+pkgAcquire::Item::~Item()
+{
+   Owner->Remove(this);
+   delete d;
+}
+									/*}}}*/
+std::string pkgAcquire::Item::Custom600Headers() const			/*{{{*/
+{
+   std::ostringstream header;
+   for (auto const &f : d->CustomFields)
+      if (f.second.empty() == false)
+	 header << '\n'
+		<< f.first << ": " << f.second;
+   return header.str();
+}
+									/*}}}*/
+std::unordered_map<std::string, std::string> &pkgAcquire::Item::ModifyCustomFields() /*{{{*/
+{
+   return d->CustomFields;
+}
+									/*}}}*/
+bool pkgAcquire::Item::PopAlternativeURI(std::string &NewURI) /*{{{*/
+{
+   if (d->AlternativeURIs.empty())
+      return false;
+   auto const AltUri = d->AlternativeURIs.front();
+   d->AlternativeURIs.pop_front();
+   NewURI = AltUri.URI;
+   auto &CustomFields = ModifyCustomFields();
+   for (auto const &f : AltUri.changefields)
+   {
+      if (f.second.empty())
+	 CustomFields.erase(f.first);
+      else
+	 CustomFields[f.first] = f.second;
+   }
+   return true;
+}
+									/*}}}*/
+bool pkgAcquire::Item::IsGoodAlternativeURI(std::string const &AltUri) const/*{{{*/
+{
+   return std::find(d->PastRedirections.cbegin(), d->PastRedirections.cend(), AltUri) == d->PastRedirections.cend() &&
+	 std::find(d->BadAlternativeSites.cbegin(), d->BadAlternativeSites.cend(), URI::SiteOnly(AltUri)) == d->BadAlternativeSites.cend();
+}
+									/*}}}*/
+void pkgAcquire::Item::PushAlternativeURI(std::string &&NewURI, std::unordered_map<std::string, std::string> &&fields, bool const at_the_back) /*{{{*/
+{
+   if (IsGoodAlternativeURI(NewURI) == false)
+      return;
+   if (at_the_back)
+      d->AlternativeURIs.emplace_back(std::move(NewURI), std::move(fields));
+   else
+      d->AlternativeURIs.emplace_front(std::move(NewURI), std::move(fields));
+}
+									/*}}}*/
+void pkgAcquire::Item::RemoveAlternativeSite(std::string &&OldSite) /*{{{*/
+{
+   d->AlternativeURIs.erase(std::remove_if(d->AlternativeURIs.begin(), d->AlternativeURIs.end(),
+					   [&](decltype(*d->AlternativeURIs.cbegin()) AltUri) {
+					      return URI::SiteOnly(AltUri.URI) == OldSite;
+					   }),
+			    d->AlternativeURIs.end());
+   d->BadAlternativeSites.push_back(std::move(OldSite));
+}
+									/*}}}*/
+std::string pkgAcquire::Item::ShortDesc() const				/*{{{*/
+{
+   return DescURI();
+}
+									/*}}}*/
+void pkgAcquire::Item::Finished()					/*{{{*/
+{
+}
+									/*}}}*/
+APT_PURE pkgAcquire * pkgAcquire::Item::GetOwner() const		/*{{{*/
+{
+   return Owner;
+}
+									/*}}}*/
+APT_PURE pkgAcquire::ItemDesc &pkgAcquire::Item::GetItemDesc()		/*{{{*/
+{
+   return Desc;
+}
+									/*}}}*/
+APT_PURE bool pkgAcquire::Item::IsTrusted() const			/*{{{*/
+{
+   return false;
+}
+									/*}}}*/
+// Acquire::Item::Failed - Item failed to download			/*{{{*/
+// ---------------------------------------------------------------------
+/* We return to an idle state if there are still other queues that could
+   fetch this object */
+static void formatHashsum(std::ostream &out, HashString const &hs)
+{
+   auto const type = hs.HashType();
+   if (type == "Checksum-FileSize")
+      out << " - Filesize";
+   else
+      out << " - " << type;
+   out << ':' << hs.HashValue();
+   if (hs.usable() == false)
+      out << " [weak]";
+   out << std::endl;
+}
+void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
+{
+   if (QueueCounter <= 1)
+   {
+      /* This indicates that the file is not available right now but might
+         be sometime later. If we do a retry cycle then this should be
+	 retried [CDROMs] */
+      if (Cnf != NULL && Cnf->LocalOnly == true &&
+	  StringToBool(LookupTag(Message,"Transient-Failure"),false) == true)
+      {
+	 Status = StatIdle;
+	 Dequeue();
+	 return;
+      }
+
+      switch (Status)
+      {
+	 case StatIdle:
+	 case StatFetching:
+	 case StatDone:
+	    Status = StatError;
+	    break;
+	 case StatAuthError:
+	 case StatError:
+	 case StatTransientNetworkError:
+	    break;
+      }
+      Complete = false;
+      Dequeue();
+   }
+
+   FailMessage(Message);
+
+   if (QueueCounter > 1)
+      Status = StatIdle;
+}
+void pkgAcquire::Item::FailMessage(string const &Message)
+{
+   string const FailReason = LookupTag(Message, "FailReason");
+   enum { MAXIMUM_SIZE_EXCEEDED, HASHSUM_MISMATCH, WEAK_HASHSUMS, REDIRECTION_LOOP, OTHER } failreason = OTHER;
+   if ( FailReason == "MaximumSizeExceeded")
+      failreason = MAXIMUM_SIZE_EXCEEDED;
+   else if ( FailReason == "WeakHashSums")
+      failreason = WEAK_HASHSUMS;
+   else if (FailReason == "RedirectionLoop")
+      failreason = REDIRECTION_LOOP;
+   else if (Status == StatAuthError)
+      failreason = HASHSUM_MISMATCH;
+
+   if(ErrorText.empty())
+   {
+      std::ostringstream out;
+      switch (failreason)
+      {
+	 case HASHSUM_MISMATCH:
+	    out << _("Hash Sum mismatch") << std::endl;
+	    break;
+	 case WEAK_HASHSUMS:
+	    out << _("Insufficient information available to perform this download securely") << std::endl;
+	    break;
+	 case REDIRECTION_LOOP:
+	    out << "Redirection loop encountered" << std::endl;
+	    break;
+	 case MAXIMUM_SIZE_EXCEEDED:
+	    out << LookupTag(Message, "Message") << std::endl;
+	    break;
+	 case OTHER:
+	    out << LookupTag(Message, "Message");
+	    break;
+      }
+
+      if (Status == StatAuthError)
+      {
+	 auto const ExpectedHashes = GetExpectedHashes();
+	 if (ExpectedHashes.empty() == false)
+	 {
+	    out << "Hashes of expected file:" << std::endl;
+	    for (auto const &hs: ExpectedHashes)
+	       formatHashsum(out, hs);
+	 }
+	 if (failreason == HASHSUM_MISMATCH)
+	 {
+	    out << "Hashes of received file:" << std::endl;
+	    for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+	    {
+	       std::string const tagname = std::string(*type) + "-Hash";
+	       std::string const hashsum = LookupTag(Message, tagname.c_str());
+	       if (hashsum.empty() == false)
+		  formatHashsum(out, HashString(*type, hashsum));
+	    }
+	 }
+	 auto const lastmod = LookupTag(Message, "Last-Modified", "");
+	 if (lastmod.empty() == false)
+	    out << "Last modification reported: " << lastmod << std::endl;
+      }
+      ErrorText = out.str();
+   }
+
+   switch (failreason)
+   {
+      case MAXIMUM_SIZE_EXCEEDED: RenameOnError(MaximumSizeExceeded); break;
+      case HASHSUM_MISMATCH: RenameOnError(HashSumMismatch); break;
+      case WEAK_HASHSUMS: break;
+      case REDIRECTION_LOOP: break;
+      case OTHER: break;
+   }
+
+   if (FailReason.empty() == false)
+      ReportMirrorFailureToCentral(*this, FailReason, ErrorText);
+   else
+      ReportMirrorFailureToCentral(*this, ErrorText, ErrorText);
+}
+									/*}}}*/
+// Acquire::Item::Start - Item has begun to download			/*{{{*/
+// ---------------------------------------------------------------------
+/* Stash status and the file size. Note that setting Complete means
+   sub-phases of the acquire process such as decompression are operating */
+void pkgAcquire::Item::Start(string const &/*Message*/, unsigned long long const Size)
+{
+   Status = StatFetching;
+   ErrorText.clear();
+   if (FileSize == 0 && Complete == false)
+      FileSize = Size;
+}
+									/*}}}*/
+// Acquire::Item::VerifyDone - check if Item was downloaded OK		/*{{{*/
+/* Note that hash-verification is 'hardcoded' in acquire-worker and has
+ * already passed if this method is called. */
+bool pkgAcquire::Item::VerifyDone(std::string const &Message,
+	 pkgAcquire::MethodConfig const * const /*Cnf*/)
+{
+   std::string const FileName = LookupTag(Message,"Filename");
+   if (FileName.empty() == true)
+   {
+      Status = StatError;
+      ErrorText = "Method gave a blank filename";
+      return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// Acquire::Item::Done - Item downloaded OK				/*{{{*/
+void pkgAcquire::Item::Done(string const &/*Message*/, HashStringList const &Hashes,
+			    pkgAcquire::MethodConfig const * const /*Cnf*/)
+{
+   // We just downloaded something..
+   if (FileSize == 0)
+   {
+      unsigned long long const downloadedSize = Hashes.FileSize();
+      if (downloadedSize != 0)
+      {
+	 FileSize = downloadedSize;
+      }
+   }
+   Status = StatDone;
+   ErrorText.clear();
+   Dequeue();
+}
+									/*}}}*/
+// Acquire::Item::Rename - Rename a file				/*{{{*/
+// ---------------------------------------------------------------------
+/* This helper function is used by a lot of item methods as their final
+   step */
+bool pkgAcquire::Item::Rename(string const &From,string const &To)
+{
+   if (From == To || rename(From.c_str(),To.c_str()) == 0)
+      return true;
+
+   std::string S;
+   strprintf(S, _("rename failed, %s (%s -> %s)."), strerror(errno),
+	 From.c_str(),To.c_str());
+   Status = StatError;
+   if (ErrorText.empty())
+      ErrorText = S;
+   else
+      ErrorText = ErrorText + ": " + S;
+   return false;
+}
+									/*}}}*/
+void pkgAcquire::Item::Dequeue()					/*{{{*/
+{
+   d->AlternativeURIs.clear();
+   Owner->Dequeue(this);
+}
+									/*}}}*/
+bool pkgAcquire::Item::RenameOnError(pkgAcquire::Item::RenameOnErrorState const error)/*{{{*/
+{
+   if (RealFileExists(DestFile))
+      Rename(DestFile, DestFile + ".FAILED");
+
+   std::string errtext;
+   switch (error)
+   {
+      case HashSumMismatch:
+	 errtext = _("Hash Sum mismatch");
+	 break;
+      case SizeMismatch:
+	 errtext = _("Size mismatch");
+	 Status = StatAuthError;
+	 break;
+      case InvalidFormat:
+	 errtext = _("Invalid file format");
+	 Status = StatError;
+	 // do not report as usually its not the mirrors fault, but Portal/Proxy
+	 break;
+      case SignatureError:
+	 errtext = _("Signature error");
+	 Status = StatError;
+	 break;
+      case NotClearsigned:
+	 strprintf(errtext, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NOSPLIT");
+	 Status = StatAuthError;
+	 break;
+      case MaximumSizeExceeded:
+	 // the method is expected to report a good error for this
+	 break;
+      case PDiffError:
+	 // no handling here, done by callers
+	 break;
+   }
+   if (ErrorText.empty())
+      ErrorText = errtext;
+   return false;
+}
+									/*}}}*/
+void pkgAcquire::Item::SetActiveSubprocess(const std::string &subprocess)/*{{{*/
+{
+      ActiveSubprocess = subprocess;
+}
+									/*}}}*/
+std::string pkgAcquire::Item::HashSum() const				/*{{{*/
+{
+   HashStringList const hashes = GetExpectedHashes();
+   HashString const * const hs = hashes.find(NULL);
+   return hs != NULL ? hs->toStr() : "";
+}
+									/*}}}*/
+void pkgAcquire::Item::FetchAfter(time_point FetchAfter) /*{{{*/
+{
+   d->FetchAfter = FetchAfter;
+}
+pkgAcquire::time_point pkgAcquire::Item::FetchAfter()
+{
+   return d->FetchAfter;
+}
+									/*}}}*/
+bool pkgAcquire::Item::IsRedirectionLoop(std::string const &NewURI)	/*{{{*/
+{
+   // store can fail due to permission errors and the item will "loop" then
+   if (APT::String::Startswith(NewURI, "store:"))
+      return false;
+   if (d->PastRedirections.empty())
+   {
+      d->PastRedirections.push_back(NewURI);
+      return false;
+   }
+   auto const LastURI = std::prev(d->PastRedirections.end());
+   // redirections to the same file are a way of restarting/resheduling,
+   // individual methods will have to make sure that they aren't looping this way
+   if (*LastURI == NewURI)
+      return false;
+   if (std::find(d->PastRedirections.begin(), LastURI, NewURI) != LastURI)
+      return true;
+   d->PastRedirections.push_back(NewURI);
+   return false;
+}
+									/*}}}*/
+int pkgAcquire::Item::Priority()					/*{{{*/
+{
+   // Stage 0: Files requested by methods
+   // - they will usually not end up here, but if they do we make sure
+   //   to get them as soon as possible as they are probably blocking
+   //   the processing of files by the requesting method
+   if (dynamic_cast<pkgAcqAuxFile *>(this) != nullptr)
+      return 5000;
+   // Stage 1: Meta indices and diff indices
+   // - those need to be fetched first to have progress reporting working
+   //   for the rest
+   if (dynamic_cast<pkgAcqMetaSig*>(this) != nullptr
+       || dynamic_cast<pkgAcqMetaBase*>(this) != nullptr
+       || dynamic_cast<pkgAcqDiffIndex*>(this) != nullptr)
+      return 1000;
+   // Stage 2: Diff files
+   // - fetch before complete indexes so we can apply the diffs while fetching
+   //   larger files.
+   if (dynamic_cast<pkgAcqIndexDiffs*>(this) != nullptr ||
+       dynamic_cast<pkgAcqIndexMergeDiffs*>(this) != nullptr)
+      return 800;
+
+   // Stage 3: The rest - complete index files and other stuff
+   return 500;
+}
+									/*}}}*/
+
+pkgAcqTransactionItem::pkgAcqTransactionItem(pkgAcquire * const Owner,	/*{{{*/
+      pkgAcqMetaClearSig * const transactionManager, IndexTarget const &target) :
+   pkgAcquire::Item(Owner), d(NULL), Target(target), TransactionManager(transactionManager)
+{
+   if (TransactionManager != this)
+      TransactionManager->Add(this);
+   ModifyCustomFields() = {
+      {"Target-Site", Target.Option(IndexTarget::SITE)},
+      {"Target-Repo-URI", Target.Option(IndexTarget::REPO_URI)},
+      {"Target-Base-URI", Target.Option(IndexTarget::BASE_URI)},
+      {"Target-Component", Target.Option(IndexTarget::COMPONENT)},
+      {"Target-Release", Target.Option(IndexTarget::RELEASE)},
+      {"Target-Architecture", Target.Option(IndexTarget::ARCHITECTURE)},
+      {"Target-Language", Target.Option(IndexTarget::LANGUAGE)},
+      {"Target-Type", "index"},
+   };
+}
+									/*}}}*/
+pkgAcqTransactionItem::~pkgAcqTransactionItem()				/*{{{*/
+{
+}
+									/*}}}*/
+HashStringList pkgAcqTransactionItem::GetExpectedHashesFor(std::string const &MetaKey) const	/*{{{*/
+{
+   return GetExpectedHashesFromFor(TransactionManager->MetaIndexParser, MetaKey);
+}
+									/*}}}*/
+
+static void LoadLastMetaIndexParser(pkgAcqMetaClearSig * const TransactionManager, std::string const &FinalRelease, std::string const &FinalInRelease)/*{{{*/
+{
+   if (TransactionManager->IMSHit == true)
+      return;
+   if (RealFileExists(FinalInRelease) || RealFileExists(FinalRelease))
+   {
+      TransactionManager->LastMetaIndexParser = TransactionManager->MetaIndexParser->UnloadedClone();
+      if (TransactionManager->LastMetaIndexParser != NULL)
+      {
+	 _error->PushToStack();
+	 if (RealFileExists(FinalInRelease))
+	    TransactionManager->LastMetaIndexParser->Load(FinalInRelease, NULL);
+	 else
+	    TransactionManager->LastMetaIndexParser->Load(FinalRelease, NULL);
+	 // its unlikely to happen, but if what we have is bad ignore it
+	 if (_error->PendingError())
+	 {
+	    delete TransactionManager->LastMetaIndexParser;
+	    TransactionManager->LastMetaIndexParser = NULL;
+	 }
+	 _error->RevertToStack();
+      }
+   }
+}
+									/*}}}*/
+
+// AcqMetaBase - Constructor						/*{{{*/
+pkgAcqMetaBase::pkgAcqMetaBase(pkgAcquire * const Owner,
+      pkgAcqMetaClearSig * const TransactionManager,
+      IndexTarget const &DataTarget)
+: pkgAcqTransactionItem(Owner, TransactionManager, DataTarget), d(NULL),
+   AuthPass(false), IMSHit(false), State(TransactionStarted)
+{
+}
+									/*}}}*/
+// AcqMetaBase::Add - Add a item to the current Transaction		/*{{{*/
+void pkgAcqMetaBase::Add(pkgAcqTransactionItem * const I)
+{
+   Transaction.push_back(I);
+}
+									/*}}}*/
+// AcqMetaBase::AbortTransaction - Abort the current Transaction	/*{{{*/
+void pkgAcqMetaBase::AbortTransaction()
+{
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "AbortTransaction: " << TransactionManager << std::endl;
+
+   switch (TransactionManager->State)
+   {
+      case TransactionStarted: break;
+      case TransactionAbort: _error->Fatal("Transaction %s was already aborted and is aborted again", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already aborted and is now committed", TransactionManager->Target.URI.c_str()); return;
+   }
+   TransactionManager->State = TransactionAbort;
+   TransactionManager->ExpectedAdditionalItems = 0;
+
+   // ensure the toplevel is in error state too
+   for (std::vector<pkgAcqTransactionItem*>::iterator I = Transaction.begin();
+        I != Transaction.end(); ++I)
+   {
+      (*I)->ExpectedAdditionalItems = 0;
+      if ((*I)->Status != pkgAcquire::Item::StatFetching)
+	 (*I)->Dequeue();
+      (*I)->TransactionState(TransactionAbort);
+   }
+   Transaction.clear();
+}
+									/*}}}*/
+// AcqMetaBase::TransactionHasError - Check for errors in Transaction	/*{{{*/
+APT_PURE bool pkgAcqMetaBase::TransactionHasError() const
+{
+   for (std::vector<pkgAcqTransactionItem*>::const_iterator I = Transaction.begin();
+        I != Transaction.end(); ++I)
+   {
+      switch((*I)->Status) {
+	 case StatDone: break;
+	 case StatIdle: break;
+	 case StatAuthError: return true;
+	 case StatError: return true;
+	 case StatTransientNetworkError: return true;
+	 case StatFetching: break;
+      }
+   }
+   return false;
+}
+									/*}}}*/
+// AcqMetaBase::CommitTransaction - Commit a transaction		/*{{{*/
+void pkgAcqMetaBase::CommitTransaction()
+{
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "CommitTransaction: " << this << std::endl;
+
+   switch (TransactionManager->State)
+   {
+      case TransactionStarted: break;
+      case TransactionAbort: _error->Fatal("Transaction %s was already committed and is now aborted", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already committed and is again committed", TransactionManager->Target.URI.c_str()); return;
+   }
+   TransactionManager->State = TransactionCommit;
+
+   // move new files into place *and* remove files that are not
+   // part of the transaction but are still on disk
+   for (std::vector<pkgAcqTransactionItem*>::iterator I = Transaction.begin();
+        I != Transaction.end(); ++I)
+   {
+      (*I)->TransactionState(TransactionCommit);
+   }
+   Transaction.clear();
+}
+									/*}}}*/
+// AcqMetaBase::TransactionStageCopy - Stage a file for copying		/*{{{*/
+void pkgAcqMetaBase::TransactionStageCopy(pkgAcqTransactionItem * const I,
+                                          const std::string &From,
+                                          const std::string &To)
+{
+   I->PartialFile = From;
+   I->DestFile = To;
+}
+									/*}}}*/
+// AcqMetaBase::TransactionStageRemoval - Stage a file for removal	/*{{{*/
+void pkgAcqMetaBase::TransactionStageRemoval(pkgAcqTransactionItem * const I,
+                                             const std::string &FinalFile)
+{
+   I->PartialFile = "";
+   I->DestFile = FinalFile;
+}
+									/*}}}*/
+// AcqMetaBase::GenerateAuthWarning - Check gpg authentication error	/*{{{*/
+/* This method is called from ::Failed handlers. If it returns true,
+   no fallback to other files or modi is performed */
+bool pkgAcqMetaBase::CheckStopAuthentication(pkgAcquire::Item * const I, const std::string &Message)
+{
+   string const Final = I->GetFinalFilename();
+   std::string const GPGError = LookupTag(Message, "Message");
+   if (FileExists(Final))
+   {
+      I->Status = StatTransientNetworkError;
+      _error->Warning(_("An error occurred during the signature verification. "
+	       "The repository is not updated and the previous index files will be used. "
+	       "GPG error: %s: %s"),
+	    Desc.Description.c_str(),
+	    GPGError.c_str());
+      RunScripts("APT::Update::Auth-Failure");
+      return true;
+   } else if (LookupTag(Message,"Message").find("NODATA") != string::npos) {
+      /* Invalid signature file, reject (LP: #346386) (Closes: #627642) */
+      _error->Error(_("GPG error: %s: %s"),
+	    Desc.Description.c_str(),
+	    GPGError.c_str());
+      I->Status = StatAuthError;
+      return true;
+   } else {
+      _error->Warning(_("GPG error: %s: %s"),
+	    Desc.Description.c_str(),
+	    GPGError.c_str());
+   }
+   // gpgv method failed
+   ReportMirrorFailureToCentral(*this, "GPGFailure", GPGError);
+   return false;
+}
+									/*}}}*/
+// AcqMetaBase::Custom600Headers - Get header for AcqMetaBase		/*{{{*/
+// ---------------------------------------------------------------------
+string pkgAcqMetaBase::Custom600Headers() const
+{
+   std::string Header = pkgAcqTransactionItem::Custom600Headers();
+   Header.append("\nIndex-File: true");
+   std::string MaximumSize;
+   strprintf(MaximumSize, "\nMaximum-Size: %i",
+             _config->FindI("Acquire::MaxReleaseFileSize", 10*1000*1000));
+   Header += MaximumSize;
+
+   string const FinalFile = GetFinalFilename();
+   struct stat Buf;
+   if (stat(FinalFile.c_str(),&Buf) == 0)
+      Header += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime, false);
+
+   return Header;
+}
+									/*}}}*/
+// AcqMetaBase::QueueForSignatureVerify					/*{{{*/
+void pkgAcqMetaBase::QueueForSignatureVerify(pkgAcqTransactionItem * const I, std::string const &File, std::string const &Signature)
+{
+   AuthPass = true;
+   I->Desc.URI = "gpgv:" + pkgAcquire::URIEncode(Signature);
+   I->DestFile = File;
+   QueueURI(I->Desc);
+   I->SetActiveSubprocess("gpgv");
+}
+									/*}}}*/
+// AcqMetaBase::CheckDownloadDone					/*{{{*/
+bool pkgAcqMetaBase::CheckDownloadDone(pkgAcqTransactionItem * const I, const std::string &Message, HashStringList const &Hashes) const
+{
+   // We have just finished downloading a Release file (it is not
+   // verified yet)
+
+   // Save the final base URI we got this Release file from
+   if (I->UsedMirror.empty() == false && _config->FindB("Acquire::SameMirrorForAllIndexes", true))
+   {
+      auto InReleasePath = Target.Option(IndexTarget::INRELEASE_PATH);
+      if (InReleasePath.empty())
+	 InReleasePath = "InRelease";
+
+      if (APT::String::Endswith(I->Desc.URI, InReleasePath))
+      {
+	 TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - InReleasePath.length());
+	 TransactionManager->UsedMirror = I->UsedMirror;
+      }
+      else if (APT::String::Endswith(I->Desc.URI, "Release"))
+      {
+	 TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - strlen("Release"));
+	 TransactionManager->UsedMirror = I->UsedMirror;
+      }
+   }
+
+   std::string const FileName = LookupTag(Message,"Filename");
+   if (FileName != I->DestFile && RealFileExists(I->DestFile) == false)
+   {
+      I->Local = true;
+      I->Desc.URI = "copy:" + pkgAcquire::URIEncode(FileName);
+      I->QueueURI(I->Desc);
+      return false;
+   }
+
+   // make sure to verify against the right file on I-M-S hit
+   bool IMSHit = StringToBool(LookupTag(Message,"IMS-Hit"), false);
+   if (IMSHit == false && Hashes.usable())
+   {
+      // detect IMS-Hits servers haven't detected by Hash comparison
+      std::string const FinalFile = I->GetFinalFilename();
+      if (RealFileExists(FinalFile) && Hashes.VerifyFile(FinalFile) == true)
+      {
+	 IMSHit = true;
+	 RemoveFile("CheckDownloadDone", I->DestFile);
+      }
+   }
+
+   if(IMSHit == true)
+   {
+      // for simplicity, the transaction manager is always InRelease
+      // even if it doesn't exist.
+      TransactionManager->IMSHit = true;
+      I->PartialFile = I->DestFile = I->GetFinalFilename();
+   }
+
+   // set Item to complete as the remaining work is all local (verify etc)
+   I->Complete = true;
+
+   return true;
+}
+									/*}}}*/
+bool pkgAcqMetaBase::CheckAuthDone(string const &Message, pkgAcquire::MethodConfig const *const Cnf) /*{{{*/
+{
+   /* If we work with a recent version of our gpgv method, we expect that it tells us
+      which key(s) have signed the file so stuff like CVE-2018-0501 is harder in the future */
+   if (Cnf->Version != "1.0" && LookupTag(Message, "Signed-By").empty())
+   {
+      std::string errmsg;
+      strprintf(errmsg, "Internal Error: Signature on %s seems good, but expected details are missing! (%s)", Target.URI.c_str(), "Signed-By");
+      if (ErrorText.empty())
+	 ErrorText = errmsg;
+      Status = StatAuthError;
+      return _error->Error("%s", errmsg.c_str());
+   }
+
+   // At this point, the gpgv method has succeeded, so there is a
+   // valid signature from a key in the trusted keyring.  We
+   // perform additional verification of its contents, and use them
+   // to verify the indexes we are about to download
+   if (_config->FindB("Debug::pkgAcquire::Auth", false))
+      std::cerr << "Signature verification succeeded: " << DestFile << std::endl;
+
+   if (TransactionManager->IMSHit == false)
+   {
+      // open the last (In)Release if we have it
+      std::string const FinalFile = GetFinalFilename();
+      std::string FinalRelease;
+      std::string FinalInRelease;
+      if (APT::String::Endswith(FinalFile, "InRelease"))
+      {
+	 FinalInRelease = FinalFile;
+	 FinalRelease = FinalFile.substr(0, FinalFile.length() - strlen("InRelease")) + "Release";
+      }
+      else
+      {
+	 FinalInRelease = FinalFile.substr(0, FinalFile.length() - strlen("Release")) + "InRelease";
+	 FinalRelease = FinalFile;
+      }
+      LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
+   }
+
+   bool const GoodAuth = TransactionManager->MetaIndexParser->Load(DestFile, &ErrorText);
+   if (GoodAuth == false && AllowInsecureRepositories(InsecureType::WEAK, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == false)
+   {
+      Status = StatAuthError;
+      return false;
+   }
+
+   if (!VerifyVendor(Message))
+   {
+      Status = StatAuthError;
+      return false;
+   }
+
+   // Download further indexes with verification
+   TransactionManager->QueueIndexes(GoodAuth);
+
+   return GoodAuth;
+}
+									/*}}}*/
+void pkgAcqMetaClearSig::QueueIndexes(bool const verify)			/*{{{*/
+{
+   // at this point the real Items are loaded in the fetcher
+   ExpectedAdditionalItems = 0;
+
+   std::unordered_set<std::string> targetsSeen, componentsSeen;
+   bool const hasReleaseFile = TransactionManager->MetaIndexParser != NULL;
+   bool hasHashes = true;
+   auto IndexTargets = TransactionManager->MetaIndexParser->GetIndexTargets();
+   if (hasReleaseFile && verify == false)
+      hasHashes = std::any_of(IndexTargets.begin(), IndexTargets.end(),
+	    [&](IndexTarget const &Target) { return TransactionManager->MetaIndexParser->Exists(Target.MetaKey); });
+   if (_config->FindB("Acquire::IndexTargets::Randomized", true) && likely(IndexTargets.empty() == false))
+   {
+      /* For fallback handling and to have some reasonable progress information
+	 we can't randomize everything, but at least the order in the same type
+	 can be as we shouldn't be telling the mirrors (and everyone else watching)
+	 which is native/foreign arch, specific order of preference of translations, … */
+      auto range_start = IndexTargets.begin();
+      auto seed = (std::chrono::high_resolution_clock::now().time_since_epoch() /  std::chrono::nanoseconds(1)) ^ getpid();
+      std::default_random_engine g(seed);
+      do {
+	 auto const type = range_start->Option(IndexTarget::CREATED_BY);
+	 auto const range_end = std::find_if_not(range_start, IndexTargets.end(),
+	       [&type](IndexTarget const &T) { return type == T.Option(IndexTarget::CREATED_BY); });
+	 std::shuffle(range_start, range_end, g);
+	 range_start = range_end;
+      } while (range_start != IndexTargets.end());
+   }
+   /* Collect all components for which files exist to prevent apt from warning users
+      about "hidden" components for which not all files exist like main/debian-installer
+      and Translation files */
+   if (hasReleaseFile == true)
+      for (auto const &Target : IndexTargets)
+	 if (TransactionManager->MetaIndexParser->Exists(Target.MetaKey))
+	 {
+	    auto component = Target.Option(IndexTarget::COMPONENT);
+	    if (component.empty() == false)
+	       componentsSeen.emplace(std::move(component));
+	 }
+
+   for (auto&& Target: IndexTargets)
+   {
+      // if we have seen a target which is created-by a target this one here is declared a
+      // fallback to, we skip acquiring the fallback (but we make sure we clean up)
+      if (targetsSeen.find(Target.Option(IndexTarget::FALLBACK_OF)) != targetsSeen.end())
+      {
+	 targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+	 new CleanupItem(Owner, TransactionManager, Target);
+	 continue;
+      }
+      // all is an implementation detail. Users shouldn't use this as arch
+      // We need this support trickery here as e.g. Debian has binary-all files already,
+      // but arch:all packages are still in the arch:any files, so we would waste precious
+      // download time, bandwidth and diskspace for nothing, BUT Debian doesn't feature all
+      // in the set of supported architectures, so we can filter based on this property rather
+      // than invent an entirely new flag we would need to carry for all of eternity.
+      if (hasReleaseFile && Target.Option(IndexTarget::ARCHITECTURE) == "all")
+      {
+	 if (TransactionManager->MetaIndexParser->IsArchitectureAllSupportedFor(Target) == false)
+	 {
+	    new CleanupItem(Owner, TransactionManager, Target);
+	    continue;
+	 }
+      }
+
+      bool trypdiff = Target.OptionBool(IndexTarget::PDIFFS);
+      if (hasReleaseFile == true)
+      {
+	 if (TransactionManager->MetaIndexParser->Exists(Target.MetaKey) == false)
+	 {
+	    auto const component = Target.Option(IndexTarget::COMPONENT);
+	    if (component.empty() == false &&
+		componentsSeen.find(component) == std::end(componentsSeen) &&
+		TransactionManager->MetaIndexParser->HasSupportForComponent(component) == false)
+	    {
+	       new CleanupItem(Owner, TransactionManager, Target);
+	       _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' doesn't have the component '%s' (component misspelt in sources.list?)"),
+		     Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str(), component.c_str());
+	       continue;
+
+	    }
+
+	    // optional targets that we do not have in the Release file are skipped
+	    if (hasHashes == true && Target.IsOptional)
+	    {
+	       new CleanupItem(Owner, TransactionManager, Target);
+	       continue;
+	    }
+
+	    std::string const &arch = Target.Option(IndexTarget::ARCHITECTURE);
+	    if (arch.empty() == false)
+	    {
+	       if (TransactionManager->MetaIndexParser->IsArchitectureSupported(arch) == false)
+	       {
+		  new CleanupItem(Owner, TransactionManager, Target);
+		  _error->Notice(_("Skipping acquire of configured file '%s' as repository '%s' doesn't support architecture '%s'"),
+			Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str(), arch.c_str());
+		  continue;
+	       }
+	       // if the architecture is officially supported but currently no packages for it available,
+	       // ignore silently as this is pretty much the same as just shipping an empty file.
+	       // if we don't know which architectures are supported, we do NOT ignore it to notify user about this
+	       if (hasHashes == true && TransactionManager->MetaIndexParser->IsArchitectureSupported("*undefined*") == false)
+	       {
+		  new CleanupItem(Owner, TransactionManager, Target);
+		  continue;
+	       }
+	    }
+
+	    if (hasHashes == true)
+	    {
+	       new CleanupItem(Owner, TransactionManager, Target);
+	       _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' does not seem to provide it (sources.list entry misspelt?)"),
+		     Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str());
+	       continue;
+	    }
+	    else
+	    {
+	       new pkgAcqIndex(Owner, TransactionManager, Target);
+	       continue;
+	    }
+	 }
+	 else if (verify)
+	 {
+	    auto const hashes = GetExpectedHashesFor(Target.MetaKey);
+	    if (hashes.empty() == false)
+	    {
+	       if (hashes.usable() == false && TargetIsAllowedToBe(TransactionManager->Target, InsecureType::WEAK) == false)
+	       {
+		  new CleanupItem(Owner, TransactionManager, Target);
+		  _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' provides only weak security information for it"),
+			Target.MetaKey.c_str(), TransactionManager->Target.Description.c_str());
+		  continue;
+	       }
+	       // empty files are skipped as acquiring the very small compressed files is a waste of time
+	       else if (hashes.FileSize() == 0)
+	       {
+		  new CleanupItem(Owner, TransactionManager, Target);
+		  targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+		  continue;
+	       }
+	    }
+	 }
+
+	 // autoselect the compression method
+	 std::vector<std::string> types = VectorizeString(Target.Option(IndexTarget::COMPRESSIONTYPES), ' ');
+	 types.erase(std::remove_if(types.begin(), types.end(), [&](std::string const &t) {
+	    if (t == "uncompressed")
+	       return TransactionManager->MetaIndexParser->Exists(Target.MetaKey) == false;
+	    std::string const MetaKey = Target.MetaKey + "." + t;
+	    return TransactionManager->MetaIndexParser->Exists(MetaKey) == false;
+	 }), types.end());
+	 if (types.empty() == false)
+	 {
+	    std::ostringstream os;
+	    std::copy(types.begin(), types.end()-1, std::ostream_iterator<std::string>(os, " "));
+	    os << *types.rbegin();
+	    Target.Options["COMPRESSIONTYPES"] = os.str();
+	 }
+	 else
+	    Target.Options["COMPRESSIONTYPES"].clear();
+
+	 std::string filename = GetExistingFilename(GetFinalFileNameFromURI(Target.URI));
+	 if (filename.empty() == false)
+	 {
+	    // if the Release file is a hit and we have an index it must be the current one
+	    if (TransactionManager->IMSHit == true)
+	       ;
+	    else if (TransactionManager->LastMetaIndexParser != NULL)
+	    {
+	       // see if the file changed since the last Release file
+	       // we use the uncompressed files as we might compress differently compared to the server,
+	       // so the hashes might not match, even if they contain the same data.
+	       HashStringList const newFile = GetExpectedHashesFromFor(TransactionManager->MetaIndexParser, Target.MetaKey);
+	       HashStringList const oldFile = GetExpectedHashesFromFor(TransactionManager->LastMetaIndexParser, Target.MetaKey);
+	       if (newFile != oldFile)
+		  filename.clear();
+	    }
+	    else
+	       filename.clear();
+	 }
+	 else
+	    trypdiff = false; // no file to patch
+
+	 if (filename.empty() == false)
+	 {
+	    new NoActionItem(Owner, Target, filename);
+	    std::string const idxfilename = GetFinalFileNameFromURI(GetDiffIndexURI(Target));
+	    if (FileExists(idxfilename))
+	       new NoActionItem(Owner, Target, idxfilename);
+	    targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+	    continue;
+	 }
+
+	 // check if we have patches available
+	 trypdiff &= TransactionManager->MetaIndexParser->Exists(GetDiffIndexFileName(Target.MetaKey));
+      }
+      else
+      {
+	 // if we have no file to patch, no point in trying
+	 trypdiff &= (GetExistingFilename(GetFinalFileNameFromURI(Target.URI)).empty() == false);
+      }
+
+      // no point in patching from local sources
+      if (trypdiff)
+      {
+	 std::string const proto = Target.URI.substr(0, strlen("file:/"));
+	 if (proto == "file:/" || proto == "copy:/" || proto == "cdrom:")
+	    trypdiff = false;
+      }
+
+      // Queue the Index file (Packages, Sources, Translation-$foo, …)
+      targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+      if (trypdiff)
+         new pkgAcqDiffIndex(Owner, TransactionManager, Target);
+      else
+         new pkgAcqIndex(Owner, TransactionManager, Target);
+   }
+}
+									/*}}}*/
+bool pkgAcqMetaBase::VerifyVendor(string const &)			/*{{{*/
+{
+   if (TransactionManager->MetaIndexParser->GetValidUntil() > 0)
+   {
+      time_t const invalid_since = time(NULL) - TransactionManager->MetaIndexParser->GetValidUntil();
+      if (invalid_since > 0)
+      {
+	 std::string errmsg;
+	 strprintf(errmsg,
+	       // TRANSLATOR: The first %s is the URL of the bad Release file, the second is
+	       // the time since then the file is invalid - formatted in the same way as in
+	       // the download progress display (e.g. 7d 3h 42min 1s)
+	       _("Release file for %s is expired (invalid since %s). "
+		  "Updates for this repository will not be applied."),
+	       Target.URI.c_str(), TimeToStr(invalid_since).c_str());
+	 if (ErrorText.empty())
+	    ErrorText = errmsg;
+	 return _error->Error("%s", errmsg.c_str());
+      }
+   }
+
+   if (TransactionManager->MetaIndexParser->GetNotBefore() > 0)
+   {
+      time_t const invalid_for = TransactionManager->MetaIndexParser->GetNotBefore() - time(nullptr);
+      if (invalid_for > 0)
+      {
+	 std::string errmsg;
+	 strprintf(errmsg,
+		   // TRANSLATOR: The first %s is the URL of the bad Release file, the second is
+		   // the time until the file will be valid - formatted in the same way as in
+		   // the download progress display (e.g. 7d 3h 42min 1s)
+		   _("Release file for %s is not valid yet (invalid for another %s). "
+		     "Updates for this repository will not be applied."),
+		   Target.URI.c_str(), TimeToStr(invalid_for).c_str());
+	 if (ErrorText.empty())
+	    ErrorText = errmsg;
+	 return _error->Error("%s", errmsg.c_str());
+      }
+   }
+
+   /* Did we get a file older than what we have? This is a last minute IMS hit and doubles
+      as a prevention of downgrading us to older (still valid) files */
+   if (TransactionManager->IMSHit == false && TransactionManager->LastMetaIndexParser != NULL &&
+	 TransactionManager->LastMetaIndexParser->GetDate() > TransactionManager->MetaIndexParser->GetDate())
+   {
+      TransactionManager->IMSHit = true;
+      RemoveFile("VerifyVendor", DestFile);
+      PartialFile = DestFile = GetFinalFilename();
+      // load the 'old' file in the 'new' one instead of flipping pointers as
+      // the new one isn't owned by us, while the old one is so cleanup would be confused.
+      TransactionManager->MetaIndexParser->swapLoad(TransactionManager->LastMetaIndexParser);
+      delete TransactionManager->LastMetaIndexParser;
+      TransactionManager->LastMetaIndexParser = NULL;
+   }
+
+   if (_config->FindB("Debug::pkgAcquire::Auth", false))
+   {
+      std::cerr << "Got Codename: " << TransactionManager->MetaIndexParser->GetCodename() << std::endl;
+      std::cerr << "Got Suite: " << TransactionManager->MetaIndexParser->GetSuite() << std::endl;
+      std::cerr << "Expecting Dist: " << TransactionManager->MetaIndexParser->GetExpectedDist() << std::endl;
+   }
+
+   // One day that might become fatal…
+   auto const ExpectedDist = TransactionManager->MetaIndexParser->GetExpectedDist();
+   auto const NowCodename = TransactionManager->MetaIndexParser->GetCodename();
+   if (TransactionManager->MetaIndexParser->CheckDist(ExpectedDist) == false)
+      _error->Warning(_("Conflicting distribution: %s (expected %s but got %s)"),
+	    Desc.Description.c_str(), ExpectedDist.c_str(), NowCodename.c_str());
+
+   // changed info potentially breaks user config like pinning
+   if (TransactionManager->LastMetaIndexParser != nullptr)
+   {
+      std::vector<pkgAcquireStatus::ReleaseInfoChange> Changes;
+      auto const AllowInfoChange = _config->FindB("Acquire::AllowReleaseInfoChange", false);
+      auto const quietInfoChange = _config->FindB("quiet::ReleaseInfoChange", false);
+      struct {
+	 char const * const Type;
+	 bool const Allowed;
+	 decltype(&metaIndex::GetOrigin) const Getter;
+      } checkers[] = {
+	 { "Origin", AllowInfoChange, &metaIndex::GetOrigin },
+	 { "Label", AllowInfoChange, &metaIndex::GetLabel },
+	 { "Version", true, &metaIndex::GetVersion }, // numbers change all the time, that is okay
+	 { "Suite", true, &metaIndex::GetSuite },
+	 { "Codename", AllowInfoChange, &metaIndex::GetCodename },
+	 { nullptr, false, nullptr }
+      };
+      auto const CheckReleaseInfo = [&](char const * const Type, bool const AllowChange, decltype(checkers[0].Getter) const Getter) {
+	 std::string const Last = (TransactionManager->LastMetaIndexParser->*Getter)();
+	 std::string const Now = (TransactionManager->MetaIndexParser->*Getter)();
+	 if (Last == Now)
+	    return;
+	 auto const Allow = _config->FindB(std::string("Acquire::AllowReleaseInfoChange::").append(Type), AllowChange);
+	 if (Allow == true && _config->FindB(std::string("quiet::ReleaseInfoChange::").append(Type), quietInfoChange) == true)
+	    return;
+	 std::string msg;
+	 strprintf(msg, _("Repository '%s' changed its '%s' value from '%s' to '%s'"),
+	       Desc.Description.c_str(), Type, Last.c_str(), Now.c_str());
+	 Changes.push_back({Type, std::move(Last), std::move(Now), std::move(msg), Allow});
+      };
+      for (short i = 0; checkers[i].Type != nullptr; ++i)
+	 CheckReleaseInfo(checkers[i].Type, checkers[i].Allowed, checkers[i].Getter);
+
+      {
+	 auto const Last = TransactionManager->LastMetaIndexParser->GetDefaultPin();
+	 auto const Now = TransactionManager->MetaIndexParser->GetDefaultPin();
+	 if (Last != Now)
+	 {
+	    auto const Allow = _config->FindB("Acquire::AllowReleaseInfoChange::DefaultPin", AllowInfoChange);
+	    if (Allow == false || _config->FindB("quiet::ReleaseInfoChange::DefaultPin", quietInfoChange) == false)
+	    {
+	       std::string msg;
+	       strprintf(msg, _("Repository '%s' changed its default priority for %s from %hi to %hi."),
+		     Desc.Description.c_str(), "apt_preferences(5)", Last, Now);
+	       Changes.push_back({"DefaultPin", std::to_string(Last), std::to_string(Now), std::move(msg), Allow});
+	    }
+	 }
+      }
+      if (Changes.empty() == false)
+      {
+	 auto const notes = TransactionManager->MetaIndexParser->GetReleaseNotes();
+	 if (notes.empty() == false)
+	 {
+	    std::string msg;
+	    // TRANSLATOR: the "this" refers to changes in the repository like a new release or owner change
+	    strprintf(msg, _("More information about this can be found online in the Release notes at: %s"), notes.c_str());
+	    Changes.push_back({"Release-Notes", "", std::move(notes), std::move(msg), true});
+	 }
+	 if (std::any_of(Changes.begin(),Changes.end(),[](pkgAcquireStatus::ReleaseInfoChange const &c) { return c.DefaultAction == false; }))
+	 {
+	    std::string msg;
+	    // TRANSLATOR: %s is the name of the manpage in question, e.g. apt-secure(8)
+	    strprintf(msg, _("This must be accepted explicitly before updates for "
+		     "this repository can be applied. See %s manpage for details."), "apt-secure(8)");
+	    Changes.push_back({"Confirmation", "", "", std::move(msg), true});
+	 }
+
+      }
+      if (Owner->Log == nullptr)
+	 return pkgAcquireStatus::ReleaseInfoChangesAsGlobalErrors(std::move(Changes));
+      return Owner->Log->ReleaseInfoChanges(TransactionManager->LastMetaIndexParser, TransactionManager->MetaIndexParser, std::move(Changes));
+   }
+   return true;
+}
+									/*}}}*/
+pkgAcqMetaBase::~pkgAcqMetaBase()
+{
+}
+
+pkgAcqMetaClearSig::pkgAcqMetaClearSig(pkgAcquire * const Owner,	/*{{{*/
+      IndexTarget const &ClearsignedTarget,
+      IndexTarget const &DetachedDataTarget, IndexTarget const &DetachedSigTarget,
+      metaIndex * const MetaIndexParser) :
+   pkgAcqMetaIndex(Owner, this, ClearsignedTarget, DetachedSigTarget),
+   d(NULL), DetachedDataTarget(DetachedDataTarget),
+   MetaIndexParser(MetaIndexParser), LastMetaIndexParser(NULL)
+{
+   // index targets + (worst case:) Release/Release.gpg
+   ExpectedAdditionalItems = std::numeric_limits<decltype(ExpectedAdditionalItems)>::max();
+   TransactionManager->Add(this);
+}
+									/*}}}*/
+pkgAcqMetaClearSig::~pkgAcqMetaClearSig()				/*{{{*/
+{
+   if (LastMetaIndexParser != NULL)
+      delete LastMetaIndexParser;
+}
+									/*}}}*/
+// pkgAcqMetaClearSig::Custom600Headers - Insert custom request headers	/*{{{*/
+string pkgAcqMetaClearSig::Custom600Headers() const
+{
+   string Header = pkgAcqMetaBase::Custom600Headers();
+   Header += "\nFail-Ignore: true";
+   std::string const key = TransactionManager->MetaIndexParser->GetSignedBy();
+   if (key.empty() == false)
+      Header += "\nSigned-By: " + QuoteString(key, "");
+
+   return Header;
+}
+									/*}}}*/
+void pkgAcqMetaClearSig::Finished()					/*{{{*/
+{
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "Finished: " << DestFile <<std::endl;
+   if(TransactionManager->State == TransactionStarted &&
+      TransactionManager->TransactionHasError() == false)
+      TransactionManager->CommitTransaction();
+}
+									/*}}}*/
+bool pkgAcqMetaClearSig::VerifyDone(std::string const &Message,		/*{{{*/
+	 pkgAcquire::MethodConfig const * const Cnf)
+{
+   if (Item::VerifyDone(Message, Cnf) == false)
+      return false;
+
+   if (FileExists(DestFile) && !StartsWithGPGClearTextSignature(DestFile))
+      return RenameOnError(NotClearsigned);
+
+   return true;
+}
+									/*}}}*/
+// pkgAcqMetaClearSig::Done - We got a file				/*{{{*/
+void pkgAcqMetaClearSig::Done(std::string const &Message,
+                              HashStringList const &Hashes,
+                              pkgAcquire::MethodConfig const * const Cnf)
+{
+   Item::Done(Message, Hashes, Cnf);
+
+   if(AuthPass == false)
+   {
+      if(CheckDownloadDone(this, Message, Hashes) == true)
+         QueueForSignatureVerify(this, DestFile, DestFile);
+      return;
+   }
+   else if (CheckAuthDone(Message, Cnf) == true)
+   {
+      if (TransactionManager->IMSHit == false)
+	 TransactionManager->TransactionStageCopy(this, DestFile, GetFinalFilename());
+      else if (RealFileExists(GetFinalFilename()) == false)
+      {
+	 // We got an InRelease file IMSHit, but we haven't one, which means
+	 // we had a valid Release/Release.gpg combo stepping in, which we have
+	 // to 'acquire' now to ensure list cleanup isn't removing them
+	 new NoActionItem(Owner, DetachedDataTarget);
+	 new NoActionItem(Owner, DetachedSigTarget);
+      }
+   }
+   else if (Status != StatAuthError)
+   {
+      string const FinalFile = GetFinalFileNameFromURI(DetachedDataTarget.URI);
+      string const OldFile = GetFinalFilename();
+      if (TransactionManager->IMSHit == false)
+	 TransactionManager->TransactionStageCopy(this, DestFile, FinalFile);
+      else if (RealFileExists(OldFile) == false)
+	 new NoActionItem(Owner, DetachedDataTarget);
+      else
+	 TransactionManager->TransactionStageCopy(this, OldFile, FinalFile);
+   }
+}
+									/*}}}*/
+void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf) /*{{{*/
+{
+   Item::Failed(Message, Cnf);
+
+   if (AuthPass == false)
+   {
+      if (Status == StatTransientNetworkError)
+      {
+	 TransactionManager->AbortTransaction();
+	 return;
+      }
+      auto const failreason = LookupTag(Message, "FailReason");
+      auto const httperror = "HttpError";
+      if (Status == StatAuthError ||
+	  Target.Option(IndexTarget::INRELEASE_PATH).empty() == false || /* do not fallback if InRelease was requested */
+	  (strncmp(failreason.c_str(), httperror, strlen(httperror)) == 0 &&
+	   failreason != "HttpError404"))
+      {
+	 // if we expected a ClearTextSignature (InRelease) but got a network
+	 // error or got a file, but it wasn't valid, we end up here (see VerifyDone).
+	 // As these is usually called by web-portals we do not try Release/Release.gpg
+	 // as this is going to fail anyway and instead abort our try (LP#346386)
+	 _error->PushToStack();
+	 _error->Error(_("Failed to fetch %s  %s"), Target.URI.c_str(), ErrorText.c_str());
+	 if (Target.Option(IndexTarget::INRELEASE_PATH).empty() == true && AllowInsecureRepositories(InsecureType::UNSIGNED, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+	    _error->RevertToStack();
+	 else
+	    return;
+      }
+
+      // Queue the 'old' InRelease file for removal if we try Release.gpg
+      // as otherwise the file will stay around and gives a false-auth
+      // impression (CVE-2012-0214)
+      TransactionManager->TransactionStageRemoval(this, GetFinalFilename());
+      Status = StatDone;
+
+      new pkgAcqMetaIndex(Owner, TransactionManager, DetachedDataTarget, DetachedSigTarget);
+   }
+   else
+   {
+      if(CheckStopAuthentication(this, Message))
+         return;
+
+      if(AllowInsecureRepositories(InsecureType::UNSIGNED, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+      {
+	 Status = StatDone;
+
+	 /* InRelease files become Release files, otherwise
+	  * they would be considered as trusted later on */
+	 string const FinalRelease = GetFinalFileNameFromURI(DetachedDataTarget.URI);
+	 string const PartialRelease = GetPartialFileNameFromURI(DetachedDataTarget.URI);
+	 string const FinalInRelease = GetFinalFilename();
+	 Rename(DestFile, PartialRelease);
+	 LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
+
+	 // we parse the indexes here because at this point the user wanted
+	 // a repository that may potentially harm him
+	 if (TransactionManager->MetaIndexParser->Load(PartialRelease, &ErrorText) == false || VerifyVendor(Message) == false)
+	    /* expired Release files are still a problem you need extra force for */;
+	 else
+	 {
+	    TransactionManager->TransactionStageCopy(this, PartialRelease, FinalRelease);
+	    TransactionManager->QueueIndexes(true);
+	 }
+      }
+   }
+}
+									/*}}}*/
+
+pkgAcqMetaIndex::pkgAcqMetaIndex(pkgAcquire * const Owner,		/*{{{*/
+                                 pkgAcqMetaClearSig * const TransactionManager,
+				 IndexTarget const &DataTarget,
+				 IndexTarget const &DetachedSigTarget) :
+   pkgAcqMetaBase(Owner, TransactionManager, DataTarget), d(NULL),
+   DetachedSigTarget(DetachedSigTarget)
+{
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "New pkgAcqMetaIndex with TransactionManager "
+                << this->TransactionManager << std::endl;
+
+   DestFile = GetPartialFileNameFromURI(DataTarget.URI);
+
+   // Create the item
+   Desc.Description = DataTarget.Description;
+   Desc.Owner = this;
+   Desc.ShortDesc = DataTarget.ShortDesc;
+
+   // Rewrite the description URI if INRELEASE_PATH was specified so
+   // we download the specified file instead.
+   auto InReleasePath = DataTarget.Option(IndexTarget::INRELEASE_PATH);
+   if (InReleasePath.empty() == false && APT::String::Endswith(DataTarget.URI, "/InRelease"))
+   {
+      Desc.URI = DataTarget.URI.substr(0, DataTarget.URI.size() - strlen("InRelease")) + InReleasePath;
+   }
+   else
+   {
+      Desc.URI = DataTarget.URI;
+   }
+
+   QueueURI(Desc);
+}
+									/*}}}*/
+void pkgAcqMetaIndex::Done(string const &Message,			/*{{{*/
+                           HashStringList const &Hashes,
+			   pkgAcquire::MethodConfig const * const Cfg)
+{
+   Item::Done(Message,Hashes,Cfg);
+
+   if(CheckDownloadDone(this, Message, Hashes))
+   {
+      // we have a Release file, now download the Signature, all further
+      // verify/queue for additional downloads will be done in the
+      // pkgAcqMetaSig::Done() code
+      new pkgAcqMetaSig(Owner, TransactionManager, DetachedSigTarget, this);
+   }
+}
+									/*}}}*/
+// pkgAcqMetaIndex::Failed - no Release file present			/*{{{*/
+void pkgAcqMetaIndex::Failed(string const &Message,
+                             pkgAcquire::MethodConfig const * const Cnf)
+{
+   pkgAcquire::Item::Failed(Message, Cnf);
+   Status = StatDone;
+
+   // No Release file was present so fall
+   // back to queueing Packages files without verification
+   // only allow going further if the user explicitly wants it
+   if(AllowInsecureRepositories(InsecureType::NORELEASE, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+   {
+      // ensure old Release files are removed
+      TransactionManager->TransactionStageRemoval(this, GetFinalFilename());
+
+      // queue without any kind of hashsum support
+      TransactionManager->QueueIndexes(false);
+   }
+}
+									/*}}}*/
+std::string pkgAcqMetaIndex::DescURI() const				/*{{{*/
+{
+   return Target.URI;
+}
+									/*}}}*/
+pkgAcqMetaIndex::~pkgAcqMetaIndex() {}
+
+// AcqMetaSig::AcqMetaSig - Constructor					/*{{{*/
+pkgAcqMetaSig::pkgAcqMetaSig(pkgAcquire * const Owner,
+      pkgAcqMetaClearSig * const TransactionManager,
+      IndexTarget const &Target,
+      pkgAcqMetaIndex * const MetaIndex) :
+   pkgAcqTransactionItem(Owner, TransactionManager, Target), d(NULL), MetaIndex(MetaIndex)
+{
+   DestFile = GetPartialFileNameFromURI(Target.URI);
+
+   // remove any partial downloaded sig-file in partial/.
+   // it may confuse proxies and is too small to warrant a
+   // partial download anyway
+   RemoveFile("pkgAcqMetaSig", DestFile);
+
+   // set the TransactionManager
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "New pkgAcqMetaSig with TransactionManager "
+                << TransactionManager << std::endl;
+
+   // Create the item
+   Desc.Description = Target.Description;
+   Desc.Owner = this;
+   Desc.ShortDesc = Target.ShortDesc;
+   Desc.URI = Target.URI;
+
+   // If we got a hit for Release, we will get one for Release.gpg too (or obscure errors),
+   // so we skip the download step and go instantly to verification
+   if (TransactionManager->IMSHit == true && RealFileExists(GetFinalFilename()))
+   {
+      Complete = true;
+      Status = StatDone;
+      PartialFile = DestFile = GetFinalFilename();
+      MetaIndexFileSignature = DestFile;
+      MetaIndex->QueueForSignatureVerify(this, MetaIndex->DestFile, DestFile);
+   }
+   else
+      QueueURI(Desc);
+}
+									/*}}}*/
+pkgAcqMetaSig::~pkgAcqMetaSig()						/*{{{*/
+{
+}
+									/*}}}*/
+// pkgAcqMetaSig::Custom600Headers - Insert custom request headers	/*{{{*/
+std::string pkgAcqMetaSig::Custom600Headers() const
+{
+   std::string Header = pkgAcqTransactionItem::Custom600Headers();
+   std::string const key = TransactionManager->MetaIndexParser->GetSignedBy();
+   if (key.empty() == false)
+      Header += "\nSigned-By: " + QuoteString(key, "");
+   return Header;
+}
+									/*}}}*/
+// AcqMetaSig::Done - The signature was downloaded/verified		/*{{{*/
+void pkgAcqMetaSig::Done(string const &Message, HashStringList const &Hashes,
+			 pkgAcquire::MethodConfig const * const Cfg)
+{
+   if (MetaIndexFileSignature.empty() == false)
+   {
+      DestFile = MetaIndexFileSignature;
+      MetaIndexFileSignature.clear();
+   }
+   Item::Done(Message, Hashes, Cfg);
+
+   if(MetaIndex->AuthPass == false)
+   {
+      if(MetaIndex->CheckDownloadDone(this, Message, Hashes) == true)
+      {
+	 // destfile will be modified to point to MetaIndexFile for the
+	 // gpgv method, so we need to save it here
+	 MetaIndexFileSignature = DestFile;
+	 MetaIndex->QueueForSignatureVerify(this, MetaIndex->DestFile, DestFile);
+      }
+      return;
+   }
+   else if (MetaIndex->CheckAuthDone(Message, Cfg) == true)
+   {
+      auto const Releasegpg = GetFinalFilename();
+      auto const Release = MetaIndex->GetFinalFilename();
+      // if this is an IMS-Hit on Release ensure we also have the Release.gpg file stored
+      // (previously an unknown pubkey) – but only if the Release file exists locally (unlikely
+      // event of InRelease removed from the mirror causing fallback but still an IMS-Hit)
+      if (TransactionManager->IMSHit == false ||
+	    (FileExists(Releasegpg) == false && FileExists(Release) == true))
+      {
+	 TransactionManager->TransactionStageCopy(this, DestFile, Releasegpg);
+	 TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, Release);
+      }
+   }
+   else if (MetaIndex->Status != StatAuthError)
+   {
+      std::string const FinalFile = MetaIndex->GetFinalFilename();
+      if (TransactionManager->IMSHit == false)
+	 TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, FinalFile);
+      else
+	 TransactionManager->TransactionStageCopy(MetaIndex, FinalFile, FinalFile);
+   }
+}
+									/*}}}*/
+void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   Item::Failed(Message,Cnf);
+
+   // check if we need to fail at this point
+   if (MetaIndex->AuthPass == true && MetaIndex->CheckStopAuthentication(this, Message))
+         return;
+
+   // ensures that a Release.gpg file in the lists/ is removed by the transaction
+   if (not MetaIndexFileSignature.empty())
+   {
+      DestFile = MetaIndexFileSignature;
+      MetaIndexFileSignature.clear();
+   }
+   TransactionManager->TransactionStageRemoval(this, DestFile);
+
+   // only allow going further if the user explicitly wants it
+   if (AllowInsecureRepositories(InsecureType::UNSIGNED, MetaIndex->Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+   {
+      string const FinalRelease = MetaIndex->GetFinalFilename();
+      string const FinalInRelease = TransactionManager->GetFinalFilename();
+      LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
+
+      // we parse the indexes here because at this point the user wanted
+      // a repository that may potentially harm him
+      bool const GoodLoad = TransactionManager->MetaIndexParser->Load(MetaIndex->DestFile, &ErrorText);
+      if (MetaIndex->VerifyVendor(Message) == false)
+	 /* expired Release files are still a problem you need extra force for */;
+      else
+      {
+	 TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, FinalRelease);
+	 TransactionManager->QueueIndexes(GoodLoad);
+      }
+   }
+   else if (TransactionManager->IMSHit == false)
+      Rename(MetaIndex->DestFile, MetaIndex->DestFile + ".FAILED");
+
+   // FIXME: this is used often (e.g. in pkgAcqIndexTrans) so refactor
+   if (Cnf->LocalOnly == true ||
+       StringToBool(LookupTag(Message,"Transient-Failure"),false) == false)
+   {
+      // Ignore this
+      Status = StatDone;
+   }
+}
+									/*}}}*/
+
+
+// AcqBaseIndex - Constructor						/*{{{*/
+pkgAcqBaseIndex::pkgAcqBaseIndex(pkgAcquire * const Owner,
+      pkgAcqMetaClearSig * const TransactionManager,
+      IndexTarget const &Target)
+: pkgAcqTransactionItem(Owner, TransactionManager, Target), d(NULL)
+{
+}
+									/*}}}*/
+void pkgAcqBaseIndex::Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   pkgAcquire::Item::Failed(Message, Cnf);
+   if (Status != StatAuthError)
+      return;
+
+   ErrorText.append("Release file created at: ");
+   auto const timespec = TransactionManager->MetaIndexParser->GetDate();
+   if (timespec == 0)
+      ErrorText.append("<unknown>");
+   else
+      ErrorText.append(TimeRFC1123(timespec, true));
+   ErrorText.append("\n");
+}
+									/*}}}*/
+pkgAcqBaseIndex::~pkgAcqBaseIndex() {}
+
+// AcqDiffIndex::AcqDiffIndex - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* Get the DiffIndex file first and see if there are patches available
+ * If so, create a pkgAcqIndexDiffs fetcher that will get and apply the
+ * patches. If anything goes wrong in that process, it will fall back to
+ * the original packages file
+ */
+pkgAcqDiffIndex::pkgAcqDiffIndex(pkgAcquire * const Owner,
+                                 pkgAcqMetaClearSig * const TransactionManager,
+                                 IndexTarget const &Target)
+   : pkgAcqIndex(Owner, TransactionManager, Target, true), d(NULL), diffs(NULL)
+{
+   // FIXME: Magic number as an upper bound on pdiffs we will reasonably acquire
+   ExpectedAdditionalItems = 40;
+   Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
+
+   CompressionExtensions.clear();
+   {
+      std::vector<std::string> types = APT::Configuration::getCompressionTypes();
+      if (types.empty() == false)
+      {
+	 std::ostringstream os;
+	 std::copy_if(types.begin(), types.end()-1, std::ostream_iterator<std::string>(os, " "), [&](std::string const type) {
+	       if (type == "uncompressed")
+	          return true;
+	       return TransactionManager->MetaIndexParser->Exists(GetDiffIndexFileName(Target.MetaKey) + '.' + type);
+	 });
+	 os << *types.rbegin();
+	 CompressionExtensions = os.str();
+      }
+   }
+   Init(GetDiffIndexURI(Target), GetDiffIndexFileName(Target.Description), Target.ShortDesc);
+
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex: " << Desc.URI << std::endl;
+}
+									/*}}}*/
+void pkgAcqDiffIndex::QueueOnIMSHit() const				/*{{{*/
+{
+   // list cleanup needs to know that this file as well as the already
+   // present index is ours, so we create an empty diff to save it for us
+   new pkgAcqIndexDiffs(Owner, TransactionManager, Target);
+}
+									/*}}}*/
+static bool RemoveFileForBootstrapLinking(std::string &ErrorText, std::string const &For, std::string const &Boot)/*{{{*/
+{
+   if (FileExists(Boot) && RemoveFile("Bootstrap-linking", Boot) == false)
+   {
+      strprintf(ErrorText, "Bootstrap for patching %s by removing stale %s failed!", For.c_str(), Boot.c_str());
+      return false;
+   }
+   return true;
+}
+									/*}}}*/
+bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)	/*{{{*/
+{
+   available_patches.clear();
+   ExpectedAdditionalItems = 0;
+   // failing here is fine: our caller will take care of trying to
+   // get the complete file if patching fails
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex::ParseIndexDiff() " << IndexDiffFile
+	 << std::endl;
+
+   FileFd Fd(IndexDiffFile, FileFd::ReadOnly, FileFd::Extension);
+   pkgTagFile TF(&Fd);
+   if (Fd.IsOpen() == false || Fd.Failed())
+      return false;
+
+   pkgTagSection Tags;
+   if(unlikely(TF.Step(Tags) == false))
+      return false;
+
+   HashStringList ServerHashes;
+   unsigned long long ServerSize = 0;
+
+   auto const &posix = std::locale::classic();
+   for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+   {
+      std::string tagname = *type;
+      tagname.append("-Current");
+      auto const tmp = Tags.Find(tagname);
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash;
+      unsigned long long size;
+      std::stringstream ss(tmp.to_string());
+      ss.imbue(posix);
+      ss >> hash >> size;
+      if (unlikely(hash.empty() == true))
+	 continue;
+      if (unlikely(ServerSize != 0 && ServerSize != size))
+	 continue;
+      ServerHashes.push_back(HashString(*type, hash));
+      ServerSize = size;
+   }
+
+   if (ServerHashes.usable() == false)
+   {
+      ErrorText = "Did not find a good hashsum in the index";
+      return false;
+   }
+
+   std::string const CurrentPackagesFile = GetFinalFileNameFromURI(Target.URI);
+   HashStringList const TargetFileHashes = GetExpectedHashesFor(Target.MetaKey);
+   if (TargetFileHashes.usable() == false || ServerHashes != TargetFileHashes)
+   {
+      ErrorText = "Index has different hashes than parser (probably older)";
+      return false;
+   }
+
+   HashStringList LocalHashes;
+   // try avoiding calculating the hash here as this is costly
+   if (TransactionManager->LastMetaIndexParser != NULL)
+      LocalHashes = GetExpectedHashesFromFor(TransactionManager->LastMetaIndexParser, Target.MetaKey);
+   if (LocalHashes.usable() == false)
+   {
+      FileFd fd(CurrentPackagesFile, FileFd::ReadOnly, FileFd::Auto);
+      Hashes LocalHashesCalc(ServerHashes);
+      LocalHashesCalc.AddFD(fd);
+      LocalHashes = LocalHashesCalc.GetHashStringList();
+   }
+
+   if (ServerHashes == LocalHashes)
+   {
+      available_patches.clear();
+      return true;
+   }
+
+   if(Debug)
+      std::clog << "Server-Current: " << ServerHashes.find(NULL)->toStr() << " and we start at "
+	 << CurrentPackagesFile << " " << LocalHashes.FileSize() << " " << LocalHashes.find(NULL)->toStr() << std::endl;
+
+   // historically, older hashes have more info than newer ones, so start
+   // collecting with older ones first to avoid implementing complicated
+   // information merging techniques… a failure is after all always
+   // recoverable with a complete file and hashes aren't changed that often.
+   std::vector<char const *> types;
+   for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+      types.push_back(*type);
+
+   // parse all of (provided) history
+   bool firstAcceptedHashes = true;
+   for (auto type = types.crbegin(); type != types.crend(); ++type)
+   {
+      if (LocalHashes.find(*type) == NULL)
+	 continue;
+
+      std::string tagname = *type;
+      tagname.append("-History");
+      auto const tmp = Tags.Find(tagname);
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp.to_string());
+      ss.imbue(posix);
+
+      while (ss >> hash >> size >> filename)
+      {
+	 if (unlikely(hash.empty() == true || filename.empty() == true))
+	    continue;
+
+	 // see if we have a record for this file already
+	 std::vector<DiffInfo>::iterator cur = available_patches.begin();
+	 for (; cur != available_patches.end(); ++cur)
+	 {
+	    if (cur->file != filename)
+	       continue;
+	    cur->result_hashes.push_back(HashString(*type, hash));
+	    break;
+	 }
+	 if (cur != available_patches.end())
+	    continue;
+	 if (firstAcceptedHashes == true)
+	 {
+	    DiffInfo next;
+	    next.file = filename;
+	    next.result_hashes.push_back(HashString(*type, hash));
+	    next.result_hashes.FileSize(size);
+	    available_patches.push_back(next);
+	 }
+	 else
+	 {
+	    if (Debug == true)
+	       std::clog << "pkgAcqDiffIndex: " << IndexDiffFile << ": File " << filename
+		  << " wasn't in the list for the first parsed hash! (history)" << std::endl;
+	    break;
+	 }
+      }
+      firstAcceptedHashes = false;
+   }
+
+   if (unlikely(available_patches.empty() == true))
+   {
+      ErrorText = "Couldn't find any patches for the patch series";
+      return false;
+   }
+
+   for (auto type = types.crbegin(); type != types.crend(); ++type)
+   {
+      if (LocalHashes.find(*type) == NULL)
+	 continue;
+
+      std::string tagname = *type;
+      tagname.append("-Patches");
+      auto const tmp = Tags.Find(tagname);
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp.to_string());
+      ss.imbue(posix);
+
+      while (ss >> hash >> size >> filename)
+      {
+	 if (unlikely(hash.empty() == true || filename.empty() == true))
+	    continue;
+
+	 // see if we have a record for this file already
+	 std::vector<DiffInfo>::iterator cur = available_patches.begin();
+	 for (; cur != available_patches.end(); ++cur)
+	 {
+	    if (cur->file != filename)
+	       continue;
+	    if (cur->patch_hashes.empty())
+	       cur->patch_hashes.FileSize(size);
+	    cur->patch_hashes.push_back(HashString(*type, hash));
+	    break;
+	 }
+	 if (cur != available_patches.end())
+	       continue;
+	 if (Debug == true)
+	    std::clog << "pkgAcqDiffIndex: " << IndexDiffFile << ": File " << filename
+	       << " wasn't in the list for the first parsed hash! (patches)" << std::endl;
+	 break;
+      }
+   }
+
+   for (auto type = types.crbegin(); type != types.crend(); ++type)
+   {
+      std::string tagname = *type;
+      tagname.append("-Download");
+      auto const tmp = Tags.Find(tagname);
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp.to_string());
+      ss.imbue(posix);
+
+      // FIXME: all of pdiff supports only .gz compressed patches
+      while (ss >> hash >> size >> filename)
+      {
+	 if (unlikely(hash.empty() == true || filename.empty() == true))
+	    continue;
+	 if (unlikely(APT::String::Endswith(filename, ".gz") == false))
+	    continue;
+	 filename.erase(filename.length() - 3);
+
+	 // see if we have a record for this file already
+	 std::vector<DiffInfo>::iterator cur = available_patches.begin();
+	 for (; cur != available_patches.end(); ++cur)
+	 {
+	    if (cur->file != filename)
+	       continue;
+	    if (cur->download_hashes.empty())
+	       cur->download_hashes.FileSize(size);
+	    cur->download_hashes.push_back(HashString(*type, hash));
+	    break;
+	 }
+	 if (cur != available_patches.end())
+	       continue;
+	 if (Debug == true)
+	    std::clog << "pkgAcqDiffIndex: " << IndexDiffFile << ": File " << filename
+	       << " wasn't in the list for the first parsed hash! (download)" << std::endl;
+	 break;
+      }
+   }
+
+   {
+      auto const foundStart = std::find_if(available_patches.rbegin(), available_patches.rend(),
+	    [&](auto const &cur) { return LocalHashes == cur.result_hashes; });
+      if (foundStart == available_patches.rend() || unlikely(available_patches.empty()))
+      {
+	 ErrorText = "Couldn't find the start of the patch series";
+	 return false;
+      }
+      available_patches.erase(available_patches.begin(), std::prev(foundStart.base()));
+
+      auto const patch = std::find_if(available_patches.cbegin(), available_patches.cend(), [](auto const &patch) {
+	 return not patch.result_hashes.usable() ||
+		not patch.patch_hashes.usable() ||
+		not patch.download_hashes.usable();
+      });
+      if (patch != available_patches.cend())
+      {
+	 strprintf(ErrorText, "Provides no usable hashes for %s", patch->file.c_str());
+	 return false;
+      }
+   }
+
+   // patching with too many files is rather slow compared to a fast download
+   unsigned long const fileLimit = _config->FindI("Acquire::PDiffs::FileLimit", 0);
+   if (fileLimit != 0 && fileLimit < available_patches.size())
+   {
+      strprintf(ErrorText, "Need %lu diffs, but limit is %lu", available_patches.size(), fileLimit);
+      return false;
+   }
+
+   /* decide if we should download patches one by one or in one go:
+      The first is good if the server merges patches, but many don't so client
+      based merging can be attempt in which case the second is better.
+      "bad things" will happen if patches are merged on the server,
+      but client side merging is attempt as well */
+   pdiff_merge = _config->FindB("Acquire::PDiffs::Merge", true);
+   if (pdiff_merge == true)
+   {
+      // reprepro and dak add this flag if they merge patches on the server
+      auto const precedence = Tags.Find("X-Patch-Precedence");
+      pdiff_merge = (precedence != "merged");
+   }
+
+   // calculate the size of all patches we have to get
+   unsigned short const sizeLimitPercent = _config->FindI("Acquire::PDiffs::SizeLimit", 100);
+   if (sizeLimitPercent > 0)
+   {
+      unsigned long long downloadSize = 0;
+      if (pdiff_merge)
+	 downloadSize = std::accumulate(available_patches.begin(), available_patches.end(), 0llu,
+					[](unsigned long long const T, DiffInfo const &I) {
+					   return T + I.download_hashes.FileSize();
+					});
+      // if server-side merging, assume we will need only the first patch
+      else if (not available_patches.empty())
+	 downloadSize = available_patches.front().download_hashes.FileSize();
+      if (downloadSize != 0)
+      {
+	 unsigned long long downloadSizeIdx = 0;
+	 auto const types = VectorizeString(Target.Option(IndexTarget::COMPRESSIONTYPES), ' ');
+	 for (auto const &t : types)
+	 {
+	    std::string MetaKey = Target.MetaKey;
+	    if (t != "uncompressed")
+	       MetaKey += '.' + t;
+	    HashStringList const hsl = GetExpectedHashesFor(MetaKey);
+	    if (unlikely(hsl.usable() == false))
+	       continue;
+	    downloadSizeIdx = hsl.FileSize();
+	    break;
+	 }
+	 unsigned long long const sizeLimit = downloadSizeIdx * sizeLimitPercent;
+	 if ((sizeLimit/100) < downloadSize)
+	 {
+	    strprintf(ErrorText, "Need %llu compressed bytes, but limit is %llu and original is %llu", downloadSize, (sizeLimit/100), downloadSizeIdx);
+	    return false;
+	 }
+      }
+   }
+
+   // clean the plate
+   {
+      std::string const Final = GetExistingFilename(CurrentPackagesFile);
+      if (unlikely(Final.empty())) // because we wouldn't be called in such a case
+	 return false;
+      std::string const PartialFile = GetPartialFileNameFromURI(Target.URI);
+      std::string const PatchedFile = GetKeepCompressedFileName(PartialFile + "-patched", Target);
+      if (not RemoveFileForBootstrapLinking(ErrorText, CurrentPackagesFile, PartialFile) ||
+	  not RemoveFileForBootstrapLinking(ErrorText, CurrentPackagesFile, PatchedFile))
+	 return false;
+      {
+	 auto const exts = APT::Configuration::getCompressorExtensions();
+	 if (not std::all_of(exts.cbegin(), exts.cend(), [&](auto const &ext) {
+		return RemoveFileForBootstrapLinking(ErrorText, CurrentPackagesFile, PartialFile + ext) &&
+		       RemoveFileForBootstrapLinking(ErrorText, CurrentPackagesFile, PatchedFile + ext);
+	     }))
+	    return false;
+      }
+      std::string const Ext = Final.substr(CurrentPackagesFile.length());
+      std::string const Partial = PartialFile + Ext;
+      if (symlink(Final.c_str(), Partial.c_str()) != 0)
+      {
+	 strprintf(ErrorText, "Bootstrap for patching by linking %s to %s failed!", Final.c_str(), Partial.c_str());
+	 return false;
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+void pkgAcqDiffIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   if (CommonFailed(GetDiffIndexURI(Target), Message, Cnf))
+      return;
+
+   RenameOnError(PDiffError);
+   Status = StatDone;
+   ExpectedAdditionalItems = 0;
+
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex failed: " << Desc.URI << " with " << Message << std::endl
+		<< "Falling back to normal index file acquire" << std::endl;
+
+   new pkgAcqIndex(Owner, TransactionManager, Target);
+}
+									/*}}}*/
+bool pkgAcqDiffIndex::VerifyDone(std::string const &Message, pkgAcquire::MethodConfig const * const)/*{{{*/
+{
+   string const FinalFile = GetFinalFilename();
+   if(StringToBool(LookupTag(Message,"IMS-Hit"),false))
+      DestFile = FinalFile;
+
+   if (ParseDiffIndex(DestFile))
+      return true;
+
+   Status = StatError;
+   if (ErrorText.empty())
+      ErrorText = "Couldn't parse pdiff index";
+   return false;
+}
+									/*}}}*/
+void pkgAcqDiffIndex::Done(string const &Message,HashStringList const &Hashes,	/*{{{*/
+			   pkgAcquire::MethodConfig const * const Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex::Done(): " << Desc.URI << std::endl;
+
+   Item::Done(Message, Hashes, Cnf);
+
+   if (available_patches.empty())
+   {
+      // we have the same sha1 as the server so we are done here
+      if(Debug)
+	 std::clog << "pkgAcqDiffIndex: Package file is up-to-date" << std::endl;
+      QueueOnIMSHit();
+   }
+   else
+   {
+      if (pdiff_merge == false)
+	 new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+      else
+      {
+	 diffs = new std::vector<pkgAcqIndexMergeDiffs*>(available_patches.size());
+	 for(size_t i = 0; i < available_patches.size(); ++i)
+	    (*diffs)[i] = new pkgAcqIndexMergeDiffs(Owner, TransactionManager,
+						    Target,
+						    available_patches[i],
+						    diffs);
+      }
+   }
+
+   TransactionManager->TransactionStageCopy(this, DestFile, GetFinalFilename());
+
+   Complete = true;
+   Status = StatDone;
+   Dequeue();
+
+   return;
+}
+									/*}}}*/
+pkgAcqDiffIndex::~pkgAcqDiffIndex()
+{
+   if (diffs != NULL)
+      delete diffs;
+}
+
+// AcqIndexDiffs::AcqIndexDiffs - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* The package diff is added to the queue. one object is constructed
+ * for each diff and the index
+ */
+pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire *const Owner,
+				   pkgAcqMetaClearSig *const TransactionManager,
+				   IndexTarget const &Target,
+				   vector<DiffInfo> const &diffs)
+    : pkgAcqBaseIndex(Owner, TransactionManager, Target),
+      available_patches(diffs)
+{
+   DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
+
+   Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
+
+   Desc.Owner = this;
+   Desc.ShortDesc = Target.ShortDesc;
+
+   if(available_patches.empty() == true)
+   {
+      // we are done (yeah!), check hashes against the final file
+      DestFile = GetKeepCompressedFileName(GetFinalFileNameFromURI(Target.URI), Target);
+      Finish(true);
+   }
+   else
+   {
+      State = StateFetchDiff;
+      QueueNextDiff();
+   }
+}
+									/*}}}*/
+void pkgAcqIndexDiffs::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   pkgAcqBaseIndex::Failed(Message,Cnf);
+   Status = StatDone;
+
+   DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs failed: " << Desc.URI << " with " << Message << std::endl
+		<< "Falling back to normal index file acquire " << std::endl;
+   RenameOnError(PDiffError);
+   std::string const patchname = GetDiffsPatchFileName(DestFile);
+   if (RealFileExists(patchname))
+      Rename(patchname, patchname + ".FAILED");
+   std::string const UnpatchedFile = GetExistingFilename(GetPartialFileNameFromURI(Target.URI));
+   if (UnpatchedFile.empty() == false && FileExists(UnpatchedFile))
+      Rename(UnpatchedFile, UnpatchedFile + ".FAILED");
+   new pkgAcqIndex(Owner, TransactionManager, Target);
+   Finish();
+}
+									/*}}}*/
+// Finish - helper that cleans the item out of the fetcher queue	/*{{{*/
+void pkgAcqIndexDiffs::Finish(bool allDone)
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs::Finish(): " 
+                << allDone << " "
+                << Desc.URI << std::endl;
+
+   // we restore the original name, this is required, otherwise
+   // the file will be cleaned
+   if(allDone)
+   {
+      std::string const Final = GetKeepCompressedFileName(GetFinalFilename(), Target);
+      TransactionManager->TransactionStageCopy(this, DestFile, Final);
+
+      // this is for the "real" finish
+      Complete = true;
+      Status = StatDone;
+      Dequeue();
+      if(Debug)
+	 std::clog << "\n\nallDone: " << DestFile << "\n" << std::endl;
+      return;
+   }
+   else
+      DestFile.clear();
+
+   if(Debug)
+      std::clog << "Finishing: " << Desc.URI << std::endl;
+   Complete = false;
+   Status = StatDone;
+   Dequeue();
+   return;
+}
+									/*}}}*/
+bool pkgAcqIndexDiffs::QueueNextDiff()					/*{{{*/
+{
+   // calc sha1 of the just patched file
+   std::string const PartialFile = GetExistingFilename(GetPartialFileNameFromURI(Target.URI));
+   if(unlikely(PartialFile.empty()))
+   {
+      Failed("Message: The file " + GetPartialFileNameFromURI(Target.URI) + " isn't available", NULL);
+      return false;
+   }
+
+   FileFd fd(PartialFile, FileFd::ReadOnly, FileFd::Extension);
+   Hashes LocalHashesCalc;
+   LocalHashesCalc.AddFD(fd);
+   HashStringList const LocalHashes = LocalHashesCalc.GetHashStringList();
+
+   if(Debug)
+      std::clog << "QueueNextDiff: " << PartialFile << " (" << LocalHashes.find(NULL)->toStr() << ")" << std::endl;
+
+   HashStringList const TargetFileHashes = GetExpectedHashesFor(Target.MetaKey);
+   if (unlikely(LocalHashes.usable() == false || TargetFileHashes.usable() == false))
+   {
+      Failed("Local/Expected hashes are not usable for " + PartialFile, NULL);
+      return false;
+   }
+
+   // final file reached before all patches are applied
+   if(LocalHashes == TargetFileHashes)
+   {
+      Finish(true);
+      return true;
+   }
+
+   // remove all patches until the next matching patch is found
+   // this requires the Index file to be ordered
+   available_patches.erase(available_patches.begin(),
+	 std::find_if(available_patches.begin(), available_patches.end(), [&](DiffInfo const &I) {
+	    return I.result_hashes == LocalHashes;
+	    }));
+
+   // error checking and falling back if no patch was found
+   if(available_patches.empty() == true)
+   {
+      Failed("No patches left to reach target for " + PartialFile, NULL);
+      return false;
+   }
+
+   // queue the right diff
+   auto const BaseFileURI = Target.URI + ".diff/" + pkgAcquire::URIEncode(available_patches[0].file);
+   Desc.URI = BaseFileURI + ".gz";
+   Desc.Description = Target.Description + " " + available_patches[0].file + string(".pdiff");
+   DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(BaseFileURI), Target);
+
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs::QueueNextDiff(): " << Desc.URI << std::endl;
+
+   QueueURI(Desc);
+
+   return true;
+}
+									/*}}}*/
+void pkgAcqIndexDiffs::Done(string const &Message, HashStringList const &Hashes,	/*{{{*/
+			    pkgAcquire::MethodConfig const * const Cnf)
+{
+   if (Debug)
+      std::clog << "pkgAcqIndexDiffs::Done(): " << Desc.URI << std::endl;
+
+   Item::Done(Message, Hashes, Cnf);
+
+   std::string const UncompressedUnpatchedFile = GetPartialFileNameFromURI(Target.URI);
+   std::string const UnpatchedFile = GetExistingFilename(UncompressedUnpatchedFile);
+   std::string const PatchFile = GetDiffsPatchFileName(UnpatchedFile);
+   std::string const PatchedFile = GetKeepCompressedFileName(UncompressedUnpatchedFile, Target);
+
+   switch (State)
+   {
+      // success in downloading a diff, enter ApplyDiff state
+      case StateFetchDiff:
+	 Rename(DestFile, PatchFile);
+	 DestFile = GetKeepCompressedFileName(UncompressedUnpatchedFile + "-patched", Target);
+	 if(Debug)
+	    std::clog << "Sending to rred method: " << UnpatchedFile << std::endl;
+	 State = StateApplyDiff;
+	 Local = true;
+	 Desc.URI = "rred:" + pkgAcquire::URIEncode(UnpatchedFile);
+	 QueueURI(Desc);
+	 SetActiveSubprocess("rred");
+	 return;
+      // success in download/apply a diff, queue next (if needed)
+      case StateApplyDiff:
+	 // remove the just applied patch and base file
+	 available_patches.erase(available_patches.begin());
+	 RemoveFile("pkgAcqIndexDiffs::Done", PatchFile);
+	 RemoveFile("pkgAcqIndexDiffs::Done", UnpatchedFile);
+	 if(Debug)
+	    std::clog << "Moving patched file in place: " << std::endl
+	       << DestFile << " -> " << PatchedFile << std::endl;
+	 Rename(DestFile, PatchedFile);
+
+	 // see if there is more to download
+	 if(available_patches.empty() == false)
+	 {
+	    new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+	    Finish();
+	 } else {
+	    DestFile = PatchedFile;
+	    Finish(true);
+	 }
+	 return;
+   }
+}
+									/*}}}*/
+std::string pkgAcqIndexDiffs::Custom600Headers() const			/*{{{*/
+{
+   if(State != StateApplyDiff)
+      return pkgAcqBaseIndex::Custom600Headers();
+   std::ostringstream patchhashes;
+   for (auto && hs : available_patches[0].result_hashes)
+      patchhashes <<  "\nStart-" << hs.HashType() << "-Hash: " << hs.HashValue();
+   for (auto && hs : available_patches[0].patch_hashes)
+      patchhashes <<  "\nPatch-0-" << hs.HashType() << "-Hash: " << hs.HashValue();
+   patchhashes << pkgAcqBaseIndex::Custom600Headers();
+   return patchhashes.str();
+}
+									/*}}}*/
+pkgAcqIndexDiffs::~pkgAcqIndexDiffs() {}
+
+// AcqIndexMergeDiffs::AcqIndexMergeDiffs - Constructor			/*{{{*/
+pkgAcqIndexMergeDiffs::pkgAcqIndexMergeDiffs(pkgAcquire *const Owner,
+					     pkgAcqMetaClearSig *const TransactionManager,
+					     IndexTarget const &Target,
+					     DiffInfo const &patch,
+					     std::vector<pkgAcqIndexMergeDiffs *> const *const allPatches)
+    : pkgAcqBaseIndex(Owner, TransactionManager, Target),
+      patch(patch), allPatches(allPatches), State(StateFetchDiff)
+{
+   Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
+
+   Desc.Owner = this;
+   Desc.ShortDesc = Target.ShortDesc;
+   Desc.URI = Target.URI + ".diff/" + pkgAcquire::URIEncode(patch.file) + ".gz";
+   Desc.Description = Target.Description + " " + patch.file + ".pdiff";
+   DestFile = GetPartialFileNameFromURI(Desc.URI);
+
+   if(Debug)
+      std::clog << "pkgAcqIndexMergeDiffs: " << Desc.URI << std::endl;
+
+   QueueURI(Desc);
+}
+									/*}}}*/
+void pkgAcqIndexMergeDiffs::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexMergeDiffs failed: " << Desc.URI << " with " << Message << std::endl;
+
+   pkgAcqBaseIndex::Failed(Message,Cnf);
+   Status = StatDone;
+
+   // check if we are the first to fail, otherwise we are done here
+   State = StateDoneDiff;
+   for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
+	 I != allPatches->end(); ++I)
+      if ((*I)->State == StateErrorDiff)
+      {
+	 State = StateErrorDiff;
+	 return;
+      }
+
+   // first failure means we should fallback
+   State = StateErrorDiff;
+   if (Debug)
+      std::clog << "Falling back to normal index file acquire" << std::endl;
+   RenameOnError(PDiffError);
+   std::string const UnpatchedFile = GetExistingFilename(GetPartialFileNameFromURI(Target.URI));
+   if (UnpatchedFile.empty() == false && FileExists(UnpatchedFile))
+      Rename(UnpatchedFile, UnpatchedFile + ".FAILED");
+   DestFile.clear();
+   new pkgAcqIndex(Owner, TransactionManager, Target);
+}
+									/*}}}*/
+void pkgAcqIndexMergeDiffs::Done(string const &Message, HashStringList const &Hashes,	/*{{{*/
+			    pkgAcquire::MethodConfig const * const Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexMergeDiffs::Done(): " << Desc.URI << std::endl;
+
+   Item::Done(Message, Hashes, Cnf);
+
+   if (std::any_of(allPatches->begin(), allPatches->end(),
+	    [](pkgAcqIndexMergeDiffs const * const P) { return P->State == StateErrorDiff; }))
+   {
+      if(Debug)
+	 std::clog << "Another patch failed already, no point in processing this one." << std::endl;
+      State = StateErrorDiff;
+      return;
+   }
+
+   std::string const UncompressedUnpatchedFile = GetPartialFileNameFromURI(Target.URI);
+   std::string const UnpatchedFile = GetExistingFilename(UncompressedUnpatchedFile);
+   if (UnpatchedFile.empty())
+   {
+      _error->Fatal("Unpatched file %s doesn't exist (anymore)!", UncompressedUnpatchedFile.c_str());
+      State = StateErrorDiff;
+      return;
+   }
+   std::string const PatchedFile = GetKeepCompressedFileName(UncompressedUnpatchedFile, Target);
+
+   switch (State)
+   {
+      case StateFetchDiff:
+	 // check if this is the last completed diff
+	 State = StateDoneDiff;
+	 for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
+	       I != allPatches->end(); ++I)
+	    if ((*I)->State != StateDoneDiff)
+	    {
+	       if(Debug)
+		  std::clog << "Not the last done diff in the batch: " << Desc.URI << std::endl;
+	       return;
+	    }
+	 for (auto * diff : *allPatches)
+	    Rename(diff->DestFile, GetMergeDiffsPatchFileName(UnpatchedFile, diff->patch.file));
+	 // this is the last completed diff, so we are ready to apply now
+	 DestFile = GetKeepCompressedFileName(UncompressedUnpatchedFile + "-patched", Target);
+	 if(Debug)
+	    std::clog << "Sending to rred method: " << UnpatchedFile << std::endl;
+	 State = StateApplyDiff;
+	 Local = true;
+	 Desc.URI = "rred:" + pkgAcquire::URIEncode(UnpatchedFile);
+	 QueueURI(Desc);
+	 SetActiveSubprocess("rred");
+	 return;
+      case StateApplyDiff:
+	 // success in download & apply all diffs, finialize and clean up
+	 if(Debug)
+	    std::clog << "Queue patched file in place: " << std::endl
+	       << DestFile << " -> " << PatchedFile << std::endl;
+
+	 // queue for copy by the transaction manager
+	 TransactionManager->TransactionStageCopy(this, DestFile, GetKeepCompressedFileName(GetFinalFilename(), Target));
+
+	 // ensure the ed's are gone regardless of list-cleanup
+	 for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
+	       I != allPatches->end(); ++I)
+	    RemoveFile("pkgAcqIndexMergeDiffs::Done", GetMergeDiffsPatchFileName(UnpatchedFile, (*I)->patch.file));
+	 RemoveFile("pkgAcqIndexMergeDiffs::Done", UnpatchedFile);
+
+	 // all set and done
+	 Complete = true;
+	 if(Debug)
+	    std::clog << "allDone: " << DestFile << "\n" << std::endl;
+	 return;
+      case StateDoneDiff: _error->Fatal("Done called for %s which is in an invalid Done state", patch.file.c_str()); break;
+      case StateErrorDiff: _error->Fatal("Done called for %s which is in an invalid Error state", patch.file.c_str()); break;
+   }
+}
+									/*}}}*/
+std::string pkgAcqIndexMergeDiffs::Custom600Headers() const		/*{{{*/
+{
+   if(State != StateApplyDiff)
+      return pkgAcqBaseIndex::Custom600Headers();
+   std::ostringstream patchhashes;
+   unsigned int seen_patches = 0;
+   for (auto && hs : (*allPatches)[0]->patch.result_hashes)
+      patchhashes <<  "\nStart-" << hs.HashType() << "-Hash: " << hs.HashValue();
+   for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
+	 I != allPatches->end(); ++I)
+   {
+      HashStringList const ExpectedHashes = (*I)->patch.patch_hashes;
+      for (HashStringList::const_iterator hs = ExpectedHashes.begin(); hs != ExpectedHashes.end(); ++hs)
+	 patchhashes <<  "\nPatch-" << std::to_string(seen_patches) << "-" << hs->HashType() << "-Hash: " << hs->HashValue();
+      ++seen_patches;
+   }
+   patchhashes << pkgAcqBaseIndex::Custom600Headers();
+   return patchhashes.str();
+}
+									/*}}}*/
+pkgAcqIndexMergeDiffs::~pkgAcqIndexMergeDiffs() {}
+
+// AcqIndex::AcqIndex - Constructor					/*{{{*/
+pkgAcqIndex::pkgAcqIndex(pkgAcquire * const Owner,
+                         pkgAcqMetaClearSig * const TransactionManager,
+                         IndexTarget const &Target, bool const Derived)
+   : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL), Stage(STAGE_DOWNLOAD),
+   CompressionExtensions(Target.Option(IndexTarget::COMPRESSIONTYPES))
+{
+   if (Derived)
+      return;
+   Init(Target.URI, Target.Description, Target.ShortDesc);
+
+   if(_config->FindB("Debug::Acquire::Transaction", false) == true)
+      std::clog << "New pkgIndex with TransactionManager "
+                << TransactionManager << std::endl;
+}
+									/*}}}*/
+// AcqIndex::Init - deferred Constructor				/*{{{*/
+void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
+                       string const &ShortDesc)
+{
+   Stage = STAGE_DOWNLOAD;
+
+   DestFile = GetPartialFileNameFromURI(URI);
+   size_t const nextExt = CompressionExtensions.find(' ');
+   if (nextExt == std::string::npos)
+   {
+      CurrentCompressionExtension = CompressionExtensions;
+      CompressionExtensions.clear();
+   }
+   else
+   {
+      CurrentCompressionExtension = CompressionExtensions.substr(0, nextExt);
+      CompressionExtensions = CompressionExtensions.substr(nextExt+1);
+   }
+
+   if (CurrentCompressionExtension == "uncompressed")
+   {
+      Desc.URI = URI;
+   }
+   else if (unlikely(CurrentCompressionExtension.empty()))
+      return;
+   else
+   {
+      Desc.URI = URI + '.' + CurrentCompressionExtension;
+      DestFile = DestFile + '.' + CurrentCompressionExtension;
+   }
+
+   // store file size of the download to ensure the fetcher gives
+   // accurate progress reporting
+   FileSize = GetExpectedHashes().FileSize();
+
+   Desc.Description = URIDesc;
+   Desc.Owner = this;
+   Desc.ShortDesc = ShortDesc;
+
+   QueueURI(Desc);
+}
+									/*}}}*/
+// AcqIndex::Custom600Headers - Insert custom request headers		/*{{{*/
+// ---------------------------------------------------------------------
+/* The only header we use is the last-modified header. */
+string pkgAcqIndex::Custom600Headers() const
+{
+   std::string msg = pkgAcqBaseIndex::Custom600Headers();
+   msg.append("\nIndex-File: true");
+
+   if (TransactionManager->LastMetaIndexParser == NULL)
+   {
+      std::string const Final = GetFinalFilename();
+
+      struct stat Buf;
+      if (stat(Final.c_str(),&Buf) == 0)
+	 msg += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime, false);
+   }
+
+   if(Target.IsOptional)
+      msg += "\nFail-Ignore: true";
+
+   return msg;
+}
+									/*}}}*/
+// AcqIndex::Failed - getting the indexfile failed			/*{{{*/
+bool pkgAcqIndex::CommonFailed(std::string const &TargetURI,
+			       std::string const &Message, pkgAcquire::MethodConfig const *const Cnf)
+{
+   pkgAcqBaseIndex::Failed(Message,Cnf);
+   // authorisation matches will not be fixed by other compression types
+   if (Status != StatAuthError)
+   {
+      if (CompressionExtensions.empty() == false)
+      {
+	 Status = StatIdle;
+	 Init(TargetURI, Desc.Description, Desc.ShortDesc);
+	 return true;
+      }
+   }
+   return false;
+}
+void pkgAcqIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
+{
+   if (CommonFailed(Target.URI, Message, Cnf))
+      return;
+
+   if(Target.IsOptional && GetExpectedHashes().empty() && Stage == STAGE_DOWNLOAD)
+      Status = StatDone;
+   else
+      TransactionManager->AbortTransaction();
+}
+									/*}}}*/
+// AcqIndex::Done - Finished a fetch					/*{{{*/
+// ---------------------------------------------------------------------
+/* This goes through a number of states.. On the initial fetch the
+   method could possibly return an alternate filename which points
+   to the uncompressed version of the file. If this is so the file
+   is copied into the partial directory. In all other cases the file
+   is decompressed with a compressed uri. */
+void pkgAcqIndex::Done(string const &Message,
+                       HashStringList const &Hashes,
+		       pkgAcquire::MethodConfig const * const Cfg)
+{
+   Item::Done(Message,Hashes,Cfg);
+
+   switch(Stage) 
+   {
+      case STAGE_DOWNLOAD:
+         StageDownloadDone(Message);
+         break;
+      case STAGE_DECOMPRESS_AND_VERIFY:
+         StageDecompressDone();
+         break;
+   }
+}
+									/*}}}*/
+// AcqIndex::StageDownloadDone - Queue for decompress and verify	/*{{{*/
+void pkgAcqIndex::StageDownloadDone(string const &Message)
+{
+   Local = true;
+   Complete = true;
+
+   std::string const AltFilename = LookupTag(Message,"Alt-Filename");
+   std::string Filename = LookupTag(Message,"Filename");
+
+   // we need to verify the file against the current Release file again
+   // on if-modified-since hit to avoid a stale attack against us
+   if (StringToBool(LookupTag(Message, "IMS-Hit"), false))
+   {
+      Filename = GetExistingFilename(GetFinalFileNameFromURI(Target.URI));
+      EraseFileName = DestFile = flCombine(flNotFile(DestFile), flNotDir(Filename));
+      if (symlink(Filename.c_str(), DestFile.c_str()) != 0)
+	 _error->WarningE("pkgAcqIndex::StageDownloadDone", "Symlinking file %s to %s failed", Filename.c_str(), DestFile.c_str());
+      Stage = STAGE_DECOMPRESS_AND_VERIFY;
+      Desc.URI = "store:" + pkgAcquire::URIEncode(DestFile);
+      QueueURI(Desc);
+      SetActiveSubprocess(::URI(Desc.URI).Access);
+      return;
+   }
+   // methods like file:// give us an alternative (uncompressed) file
+   else if (Target.KeepCompressed == false && AltFilename.empty() == false)
+   {
+      Filename = AltFilename;
+      EraseFileName.clear();
+   }
+   // Methods like e.g. "file:" will give us a (compressed) FileName that is
+   // not the "DestFile" we set, in this case we uncompress from the local file
+   else if (Filename != DestFile && RealFileExists(DestFile) == false)
+   {
+      // symlinking ensures that the filename can be used for compression detection
+      // that is e.g. needed for by-hash which has no extension over file
+      if (symlink(Filename.c_str(),DestFile.c_str()) != 0)
+	 _error->WarningE("pkgAcqIndex::StageDownloadDone", "Symlinking file %s to %s failed", Filename.c_str(), DestFile.c_str());
+      else
+      {
+	 EraseFileName = DestFile;
+	 Filename = DestFile;
+      }
+   }
+
+   Stage = STAGE_DECOMPRESS_AND_VERIFY;
+   DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
+   if (Filename != DestFile && flExtension(Filename) == flExtension(DestFile))
+      Desc.URI = "copy:" + pkgAcquire::URIEncode(Filename);
+   else
+      Desc.URI = "store:" + pkgAcquire::URIEncode(Filename);
+   if (DestFile == Filename)
+   {
+      if (CurrentCompressionExtension == "uncompressed")
+	 return StageDecompressDone();
+      DestFile = "/dev/null";
+   }
+
+   if (EraseFileName.empty() && Filename != AltFilename)
+      EraseFileName = Filename;
+
+   // queue uri for the next stage
+   QueueURI(Desc);
+   SetActiveSubprocess(::URI(Desc.URI).Access);
+}
+									/*}}}*/
+// AcqIndex::StageDecompressDone - Final verification			/*{{{*/
+void pkgAcqIndex::StageDecompressDone()
+{
+   if (DestFile == "/dev/null")
+      DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
+
+   // Done, queue for rename on transaction finished
+   TransactionManager->TransactionStageCopy(this, DestFile, GetFinalFilename());
+}
+									/*}}}*/
+pkgAcqIndex::~pkgAcqIndex() {}
+
+// AcqArchive::AcqArchive - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* This just sets up the initial fetch environment and queues the first
+   possibilitiy */
+pkgAcqArchive::pkgAcqArchive(pkgAcquire *const Owner, pkgSourceList *const Sources,
+			     pkgRecords *const Recs, pkgCache::VerIterator const &Version,
+			     string &StoreFilename) : Item(Owner), d(NULL), LocalSource(false), Version(Version), Sources(Sources), Recs(Recs),
+						      StoreFilename(StoreFilename),
+						      Trusted(false)
+{
+   if (Version.Arch() == 0)
+   {
+      _error->Error(_("I wasn't able to locate a file for the %s package. "
+		      "This might mean you need to manually fix this package. "
+		      "(due to missing arch)"),
+		    Version.ParentPkg().FullName().c_str());
+      return;
+   }
+
+   // check if we have one trusted source for the package. if so, switch
+   // to "TrustedOnly" mode - but only if not in AllowUnauthenticated mode
+   bool const allowUnauth = _config->FindB("APT::Get::AllowUnauthenticated", false);
+   bool const debugAuth = _config->FindB("Debug::pkgAcquire::Auth", false);
+   bool seenUntrusted = false;
+   for (pkgCache::VerFileIterator i = Version.FileList(); i.end() == false; ++i)
+   {
+      pkgIndexFile *Index;
+      if (Sources->FindIndex(i.File(),Index) == false)
+         continue;
+
+      if (debugAuth == true)
+         std::cerr << "Checking index: " << Index->Describe()
+                   << "(Trusted=" << Index->IsTrusted() << ")" << std::endl;
+
+      if (Index->IsTrusted() == true)
+      {
+         Trusted = true;
+	 if (allowUnauth == false)
+	    break;
+      }
+      else
+         seenUntrusted = true;
+   }
+
+   // "allow-unauthenticated" restores apts old fetching behaviour
+   // that means that e.g. unauthenticated file:// uris are higher
+   // priority than authenticated http:// uris
+   if (allowUnauth == true && seenUntrusted == true)
+      Trusted = false;
+
+   StoreFilename.clear();
+   for (auto Vf = Version.FileList(); Vf.end() == false; ++Vf)
+   {
+      auto const PkgF = Vf.File();
+      if (unlikely(PkgF.end()))
+	 continue;
+      if (PkgF.Flagged(pkgCache::Flag::NotSource))
+	 continue;
+      pkgIndexFile *Index;
+      if (Sources->FindIndex(PkgF, Index) == false)
+	 continue;
+      if (Trusted && Index->IsTrusted() == false)
+	 continue;
+
+      pkgRecords::Parser &Parse = Recs->Lookup(Vf);
+      // collect the hashes from the indexes
+      auto hsl = Parse.Hashes();
+      if (ExpectedHashes.empty())
+	 ExpectedHashes = hsl;
+      else
+      {
+	 // bad things will likely happen, but the user might be "lucky" still
+	 // if the sources provide the same hashtypes (so that they aren't mixed)
+	 for (auto const &hs : hsl)
+	    if (ExpectedHashes.push_back(hs) == false)
+	    {
+	       _error->Warning("Sources disagree on hashes for supposedly identical version '%s' of '%s'.",
+			       Version.VerStr(), Version.ParentPkg().FullName(false).c_str());
+	       break;
+	    }
+      }
+      // only allow local volatile sources to have no hashes
+      if (PkgF.Flagged(pkgCache::Flag::LocalSource))
+	 LocalSource = true;
+      else if (hsl.empty())
+	 continue;
+
+      std::string poolfilename = Parse.FileName();
+      if (poolfilename.empty())
+	 continue;
+
+      std::remove_reference<decltype(ModifyCustomFields())>::type fields;
+      {
+	 auto const debIndex = dynamic_cast<pkgDebianIndexTargetFile const *const>(Index);
+	 if (debIndex != nullptr)
+	 {
+	    auto const IT = debIndex->GetIndexTarget();
+	    fields.emplace("Target-Repo-URI", IT.Option(IndexTarget::REPO_URI));
+	    fields.emplace("Target-Release", IT.Option(IndexTarget::RELEASE));
+	    fields.emplace("Target-Site", IT.Option(IndexTarget::SITE));
+	 }
+      }
+      fields.emplace("Target-Base-URI", Index->ArchiveURI(""));
+      if (PkgF->Component != 0)
+	 fields.emplace("Target-Component", PkgF.Component());
+      auto const RelF = PkgF.ReleaseFile();
+      if (RelF.end() == false)
+      {
+	 if (RelF->Codename != 0)
+	    fields.emplace("Target-Codename", RelF.Codename());
+	 if (RelF->Archive != 0)
+	    fields.emplace("Target-Suite", RelF.Archive());
+      }
+      fields.emplace("Target-Architecture", Version.Arch());
+      fields.emplace("Target-Type", flExtension(poolfilename));
+
+      if (StoreFilename.empty())
+      {
+	 /* We pick a filename based on the information we have for the version,
+	    but we don't know what extension such a file should have, so we look
+	    at the filenames used online and assume that they are the same for
+	    all repositories containing this file */
+	 StoreFilename = QuoteString(Version.ParentPkg().Name(), "_:") + '_' +
+			 QuoteString(Version.VerStr(), "_:") + '_' +
+			 QuoteString(Version.Arch(), "_:.") +
+			 "." + flExtension(poolfilename);
+
+	 Desc.URI = Index->ArchiveURI(poolfilename);
+	 Desc.Description = Index->ArchiveInfo(Version);
+	 Desc.Owner = this;
+	 Desc.ShortDesc = Version.ParentPkg().FullName(true);
+	 auto &customfields = ModifyCustomFields();
+	 for (auto const &f : fields)
+	    customfields[f.first] = f.second;
+	 FileSize = Version->Size;
+      }
+      else
+	 PushAlternativeURI(Index->ArchiveURI(poolfilename), std::move(fields), true);
+   }
+   if (StoreFilename.empty())
+   {
+      _error->Error(_("Can't find a source to download version '%s' of '%s'"),
+		    Version.VerStr(), Version.ParentPkg().FullName(false).c_str());
+      return;
+   }
+   if (FileSize == 0 && not _config->FindB("Acquire::AllowUnsizedPackages", false))
+   {
+      _error->Error("Repository is broken: %s has no Size information",
+		    Desc.Description.c_str());
+      return;
+   }
+
+   // Check if we already downloaded the file
+   struct stat Buf;
+   auto FinalFile = _config->FindDir("Dir::Cache::Archives") + flNotDir(StoreFilename);
+   if (stat(FinalFile.c_str(), &Buf) == 0)
+   {
+      // Make sure the size matches
+      if ((unsigned long long)Buf.st_size == Version->Size)
+      {
+	 Complete = true;
+	 Local = true;
+	 Status = StatDone;
+	 StoreFilename = DestFile = FinalFile;
+	 return;
+      }
+
+      /* Hmm, we have a file and its size does not match, this shouldn't
+	 happen.. */
+      RemoveFile("pkgAcqArchive::QueueNext", FinalFile);
+   }
+
+   // Check the destination file
+   DestFile = _config->FindDir("Dir::Cache::Archives") + "partial/" + flNotDir(StoreFilename);
+   if (stat(DestFile.c_str(), &Buf) == 0)
+   {
+      // Hmm, the partial file is too big, erase it
+      if ((unsigned long long)Buf.st_size > Version->Size)
+	 RemoveFile("pkgAcqArchive::QueueNext", DestFile);
+      else
+	 PartialSize = Buf.st_size;
+   }
+
+   // Disables download of archives - useful if no real installation follows,
+   // e.g. if we are just interested in proposed installation order
+   if (_config->FindB("Debug::pkgAcqArchive::NoQueue", false) == true)
+   {
+      Complete = true;
+      Local = true;
+      Status = StatDone;
+      StoreFilename = DestFile = FinalFile;
+      return;
+   }
+
+   // Create the item
+   Local = false;
+   QueueURI(Desc);
+}
+									/*}}}*/
+bool pkgAcqArchive::QueueNext() /*{{{*/
+{
+   return false;
+}
+									/*}}}*/
+// AcqArchive::Done - Finished fetching					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcqArchive::Done(string const &Message, HashStringList const &Hashes,
+			 pkgAcquire::MethodConfig const * const Cfg)
+{
+   Item::Done(Message, Hashes, Cfg);
+
+   // Grab the output filename
+   std::string const FileName = LookupTag(Message,"Filename");
+   if (DestFile !=  FileName && RealFileExists(DestFile) == false)
+   {
+      StoreFilename = DestFile = FileName;
+      Local = true;
+      Complete = true;
+      return;
+   }
+
+   // Done, move it into position
+   string const FinalFile = GetFinalFilename();
+   Rename(DestFile,FinalFile);
+   StoreFilename = DestFile = FinalFile;
+   Complete = true;
+}
+									/*}}}*/
+// AcqArchive::Failed - Failure handler					/*{{{*/
+// ---------------------------------------------------------------------
+/* Here we try other sources */
+void pkgAcqArchive::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
+{
+   Item::Failed(Message,Cnf);
+}
+									/*}}}*/
+APT_PURE bool pkgAcqArchive::IsTrusted() const				/*{{{*/
+{
+   return Trusted;
+}
+									/*}}}*/
+void pkgAcqArchive::Finished()						/*{{{*/
+{
+   if (Status == pkgAcquire::Item::StatDone &&
+       Complete == true)
+      return;
+   StoreFilename = string();
+}
+									/*}}}*/
+std::string pkgAcqArchive::DescURI() const				/*{{{*/
+{
+   return Desc.URI;
+}
+									/*}}}*/
+std::string pkgAcqArchive::ShortDesc() const				/*{{{*/
+{
+   return Desc.ShortDesc;
+}
+									/*}}}*/
+pkgAcqArchive::~pkgAcqArchive() {}
+
+// AcqChangelog::pkgAcqChangelog - Constructors				/*{{{*/
+class pkgAcqChangelog::Private
+{
+   public:
+   std::string FinalFile;
+};
+pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::VerIterator const &Ver,
+      std::string const &DestDir, std::string const &DestFilename) :
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(Ver.SourcePkgName()), SrcVersion(Ver.SourceVerStr())
+{
+   Desc.URI = URI(Ver);
+   Init(DestDir, DestFilename);
+}
+// some parameters are char* here as they come likely from char* interfaces – which can also return NULL
+pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::RlsFileIterator const &RlsFile,
+      char const * const Component, char const * const SrcName, char const * const SrcVersion,
+      const string &DestDir, const string &DestFilename) :
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(SrcName), SrcVersion(SrcVersion)
+{
+   Desc.URI = URI(RlsFile, Component, SrcName, SrcVersion);
+   Init(DestDir, DestFilename);
+}
+pkgAcqChangelog::pkgAcqChangelog(pkgAcquire * const Owner,
+      std::string const &URI, char const * const SrcName, char const * const SrcVersion,
+      const string &DestDir, const string &DestFilename) :
+   pkgAcquire::Item(Owner), d(new pkgAcqChangelog::Private()), SrcName(SrcName), SrcVersion(SrcVersion)
+{
+   Desc.URI = URI;
+   Init(DestDir, DestFilename);
+}
+void pkgAcqChangelog::Init(std::string const &DestDir, std::string const &DestFilename)
+{
+   if (Desc.URI.empty())
+   {
+      Status = StatError;
+      // TRANSLATOR: %s=%s is sourcename=sourceversion, e.g. apt=1.1
+      strprintf(ErrorText, _("Changelog unavailable for %s=%s"), SrcName.c_str(), SrcVersion.c_str());
+      // Let the error message print something sensible rather than "Failed to fetch /"
+      if (DestFilename.empty())
+	 DestFile = SrcName + ".changelog";
+      else
+	 DestFile = DestFilename;
+      Desc.URI = "changelog:/" + pkgAcquire::URIEncode(DestFile);
+      return;
+   }
+
+   std::string DestFileName;
+   if (DestFilename.empty())
+      DestFileName = flCombine(DestFile, SrcName + ".changelog");
+   else
+      DestFileName = flCombine(DestFile, DestFilename);
+
+   std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+   std::string const systemTemp = GetTempDir(SandboxUser);
+   char tmpname[1000];
+   snprintf(tmpname, sizeof(tmpname), "%s/apt-changelog-XXXXXX", systemTemp.c_str());
+   if (NULL == mkdtemp(tmpname))
+   {
+      _error->Errno("mkdtemp", "mkdtemp failed in changelog acquire of %s %s", SrcName.c_str(), SrcVersion.c_str());
+      Status = StatError;
+      return;
+   }
+   TemporaryDirectory = tmpname;
+
+   ChangeOwnerAndPermissionOfFile("pkgAcqChangelog::Init", TemporaryDirectory.c_str(),
+	 SandboxUser.c_str(), ROOT_GROUP, 0700);
+
+   DestFile = flCombine(TemporaryDirectory, DestFileName);
+   if (DestDir.empty() == false)
+   {
+      d->FinalFile = flCombine(DestDir, DestFileName);
+      if (RealFileExists(d->FinalFile))
+      {
+	 FileFd file1, file2;
+	 if (file1.Open(DestFile, FileFd::WriteOnly | FileFd::Create | FileFd::Exclusive) &&
+	       file2.Open(d->FinalFile, FileFd::ReadOnly) && CopyFile(file2, file1))
+	 {
+	    ChangeOwnerAndPermissionOfFile("pkgAcqChangelog::Init", DestFile.c_str(), "root", ROOT_GROUP, 0644);
+	    struct timeval times[2];
+	    times[0].tv_sec = times[1].tv_sec = file2.ModificationTime();
+	    times[0].tv_usec = times[1].tv_usec = 0;
+	    utimes(DestFile.c_str(), times);
+	 }
+      }
+   }
+
+   Desc.ShortDesc = "Changelog";
+   strprintf(Desc.Description, "%s %s %s Changelog", URI::SiteOnly(Desc.URI).c_str(), SrcName.c_str(), SrcVersion.c_str());
+   Desc.Owner = this;
+   QueueURI(Desc);
+}
+									/*}}}*/
+std::string pkgAcqChangelog::URI(pkgCache::VerIterator const &Ver)	/*{{{*/
+{
+   std::string const confOnline = "Acquire::Changelogs::AlwaysOnline";
+   bool AlwaysOnline = _config->FindB(confOnline, false);
+   if (AlwaysOnline == false)
+      for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
+      {
+	 pkgCache::PkgFileIterator const PF = VF.File();
+	 if (PF.Flagged(pkgCache::Flag::NotSource) || PF->Release == 0)
+	    continue;
+	 pkgCache::RlsFileIterator const RF = PF.ReleaseFile();
+	 if (RF->Origin != 0 && _config->FindB(confOnline + "::Origin::" + RF.Origin(), false))
+	 {
+	    AlwaysOnline = true;
+	    break;
+	 }
+      }
+   if (AlwaysOnline == false)
+   {
+      pkgCache::PkgIterator const Pkg = Ver.ParentPkg();
+      if (Pkg->CurrentVer != 0 && Pkg.CurrentVer() == Ver)
+      {
+	 auto const LocalFile = [](pkgCache::PkgIterator const &Pkg) -> std::string {
+	    std::string const root = _config->FindDir("Dir");
+	    std::string const basename = root + std::string("usr/share/doc/") + Pkg.Name() + "/changelog";
+	    std::string const debianname = basename + ".Debian";
+	    auto const exts = APT::Configuration::getCompressorExtensions(); // likely we encounter only .gz
+	    for (auto file : { debianname, basename })
+	    {
+	       if (FileExists(file))
+		  return "copy://" + file;
+	       for (auto const& ext : exts)
+	       {
+		  auto const compressedfile = file + ext;
+		  if (FileExists(compressedfile))
+		     return "store://" + compressedfile;
+	       }
+	    }
+	    return "";
+	 }(Pkg);
+	 if (not LocalFile.empty())
+	 {
+	    _error->PushToStack();
+	    FileFd trimmed;
+	    if (APT::String::Startswith(LocalFile, "copy://"))
+	       trimmed.Open(LocalFile.substr(7), FileFd::ReadOnly, FileFd::None);
+	    else
+	       trimmed.Open(LocalFile.substr(8), FileFd::ReadOnly, FileFd::Extension);
+
+	    bool trimmedFile = false;
+	    if (trimmed.IsOpen())
+	    {
+	       /* We want to look at the last line… in a (likely) compressed file,
+		  which means we more or less have to uncompress the entire file.
+		  So we skip ahead the filesize minus our choosen line size in
+		  the hope that changelogs don't grow by being compressed to
+		  avoid doing this costly dance on at least a bit of the file. */
+	       char buffer[150];
+	       if (auto const filesize = trimmed.FileSize(); filesize > sizeof(buffer))
+		  trimmed.Skip(filesize - sizeof(buffer));
+	       std::string_view giveaways[] = {
+		  "# To read the complete changelog use", // Debian
+		  "# For older changelog entries, run", // Ubuntu
+	       };
+	       while (trimmed.ReadLine(buffer, sizeof(buffer)) != nullptr)
+	       {
+		  std::string_view const line{buffer};
+		  if (std::any_of(std::begin(giveaways), std::end(giveaways), [=](auto const gw) { return line.compare(0, gw.size(), gw) == 0; }))
+		  {
+		     trimmedFile = true;
+		     break;
+		  }
+	       }
+	    }
+	    _error->RevertToStack();
+	    if (not trimmedFile)
+	       return LocalFile;
+	 }
+      }
+   }
+
+   char const * const SrcName = Ver.SourcePkgName();
+   char const * const SrcVersion = Ver.SourceVerStr();
+   // find the first source for this version which promises a changelog
+   for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
+   {
+      pkgCache::PkgFileIterator const PF = VF.File();
+      if (PF.Flagged(pkgCache::Flag::NotSource) || PF->Release == 0)
+	 continue;
+      pkgCache::RlsFileIterator const RF = PF.ReleaseFile();
+      std::string const uri = URI(RF, PF.Component(), SrcName, SrcVersion);
+      if (uri.empty())
+	 continue;
+      return uri;
+   }
+   return "";
+}
+std::string pkgAcqChangelog::URITemplate(pkgCache::RlsFileIterator const &Rls)
+{
+   if (Rls.end() == true || (Rls->Label == 0 && Rls->Origin == 0))
+      return "";
+   std::string const serverConfig = "Acquire::Changelogs::URI";
+   std::string server;
+#define APT_EMPTY_SERVER \
+   if (server.empty() == false) \
+   { \
+      if (server != "no") \
+	 return server; \
+      return ""; \
+   }
+#define APT_CHECK_SERVER(X, Y) \
+   if (Rls->X != 0) \
+   { \
+      std::string const specialServerConfig = serverConfig + "::" + Y + #X + "::" + Rls.X(); \
+      server = _config->Find(specialServerConfig); \
+      APT_EMPTY_SERVER \
+   }
+   // this way e.g. Debian-Security can fallback to Debian
+   APT_CHECK_SERVER(Label, "Override::")
+   APT_CHECK_SERVER(Origin, "Override::")
+
+   if (RealFileExists(Rls.FileName()))
+   {
+      _error->PushToStack();
+      FileFd rf;
+      /* This can be costly. A caller wanting to get millions of URIs might
+	 want to do this on its own once and use Override settings.
+	 We don't do this here as Origin/Label are not as unique as they
+	 should be so this could produce request order-dependent anomalies */
+      if (OpenMaybeClearSignedFile(Rls.FileName(), rf) == true)
+      {
+	 pkgTagFile TagFile(&rf, rf.Size());
+	 pkgTagSection Section;
+	 if (TagFile.Step(Section) == true)
+	    server = Section.FindS("Changelogs");
+      }
+      _error->RevertToStack();
+      APT_EMPTY_SERVER
+   }
+
+   APT_CHECK_SERVER(Label, "")
+   APT_CHECK_SERVER(Origin, "")
+#undef APT_CHECK_SERVER
+#undef APT_EMPTY_SERVER
+   return "";
+}
+std::string pkgAcqChangelog::URI(pkgCache::RlsFileIterator const &Rls,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion)
+{
+   return URI(URITemplate(Rls), Component, SrcName, SrcVersion);
+}
+std::string pkgAcqChangelog::URI(std::string const &Template,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion)
+{
+   if (Template.find("@CHANGEPATH@") == std::string::npos)
+      return "";
+
+   // the path is: COMPONENT/SRC/SRCNAME/SRCNAME_SRCVER, e.g. main/a/apt/apt_1.1 or contrib/liba/libapt/libapt_2.0
+   std::string const Src{SrcName};
+   std::string path = pkgAcquire::URIEncode(APT::String::Startswith(SrcName, "lib") ? Src.substr(0, 4) : Src.substr(0,1));
+   path.append("/").append(pkgAcquire::URIEncode(Src)).append("/");
+   path.append(pkgAcquire::URIEncode(Src)).append("_").append(pkgAcquire::URIEncode(StripEpoch(SrcVersion)));
+   // we omit component for releases without one (= flat-style repositories)
+   if (Component != NULL && strlen(Component) != 0)
+      path = pkgAcquire::URIEncode(Component) + "/" + path;
+
+   return SubstVar(Template, "@CHANGEPATH@", path);
+}
+									/*}}}*/
+// AcqChangelog::Failed - Failure handler				/*{{{*/
+void pkgAcqChangelog::Failed(string const &Message, pkgAcquire::MethodConfig const * const Cnf)
+{
+   Item::Failed(Message,Cnf);
+
+   std::string errText;
+   // TRANSLATOR: %s=%s is sourcename=sourceversion, e.g. apt=1.1
+   strprintf(errText, _("Changelog unavailable for %s=%s"), SrcName.c_str(), SrcVersion.c_str());
+
+   // Error is probably something techy like 404 Not Found
+   if (ErrorText.empty())
+      ErrorText = errText;
+   else
+      ErrorText = errText + " (" + ErrorText + ")";
+}
+									/*}}}*/
+// AcqChangelog::Done - Item downloaded OK				/*{{{*/
+void pkgAcqChangelog::Done(string const &Message,HashStringList const &CalcHashes,
+		      pkgAcquire::MethodConfig const * const Cnf)
+{
+   Item::Done(Message,CalcHashes,Cnf);
+   if (d->FinalFile.empty() == false)
+   {
+      if (RemoveFile("pkgAcqChangelog::Done", d->FinalFile) == false ||
+	    Rename(DestFile, d->FinalFile) == false)
+	 Status = StatError;
+   }
+
+   Complete = true;
+}
+									/*}}}*/
+pkgAcqChangelog::~pkgAcqChangelog()					/*{{{*/
+{
+   if (TemporaryDirectory.empty() == false)
+   {
+      RemoveFile("~pkgAcqChangelog", DestFile);
+      rmdir(TemporaryDirectory.c_str());
+   }
+   delete d;
+}
+									/*}}}*/
+
+// AcqFile::pkgAcqFile - Constructor					/*{{{*/
+pkgAcqFile::pkgAcqFile(pkgAcquire *const Owner, string const &URI, HashStringList const &Hashes,
+		       unsigned long long const Size, string const &Dsc, string const &ShortDesc,
+		       const string &DestDir, const string &DestFilename,
+		       bool const IsIndexFile) : Item(Owner), d(NULL), IsIndexFile(IsIndexFile), ExpectedHashes(Hashes)
+{
+   ::URI url{URI};
+   if (url.Path.find(' ') != std::string::npos || url.Path.find('%') == std::string::npos)
+      url.Path = pkgAcquire::URIEncode(url.Path);
+
+   if(!DestFilename.empty())
+      DestFile = DestFilename;
+   else if(!DestDir.empty())
+      DestFile = DestDir + "/" + DeQuoteString(flNotDir(url.Path));
+   else
+      DestFile = DeQuoteString(flNotDir(url.Path));
+
+   // Create the item
+   Desc.URI = std::string(url);
+   Desc.Description = Dsc;
+   Desc.Owner = this;
+
+   // Set the short description to the archive component
+   Desc.ShortDesc = ShortDesc;
+
+   // Get the transfer sizes
+   FileSize = Size;
+   struct stat Buf;
+   if (stat(DestFile.c_str(),&Buf) == 0)
+   {
+      // Hmm, the partial file is too big, erase it
+      if ((Size > 0) && (unsigned long long)Buf.st_size > Size)
+	 RemoveFile("pkgAcqFile", DestFile);
+      else
+	 PartialSize = Buf.st_size;
+   }
+
+   QueueURI(Desc);
+}
+									/*}}}*/
+// AcqFile::Done - Item downloaded OK					/*{{{*/
+void pkgAcqFile::Done(string const &Message,HashStringList const &CalcHashes,
+		      pkgAcquire::MethodConfig const * const Cnf)
+{
+   Item::Done(Message,CalcHashes,Cnf);
+
+   std::string const FileName = LookupTag(Message,"Filename");
+   Complete = true;
+
+   // The files timestamp matches
+   if (StringToBool(LookupTag(Message,"IMS-Hit"),false) == true)
+      return;
+
+   // We have to copy it into place
+   if (RealFileExists(DestFile.c_str()) == false)
+   {
+      Local = true;
+      if (_config->FindB("Acquire::Source-Symlinks",true) == false ||
+	  Cnf->Removable == true)
+      {
+	 Desc.URI = "copy:" + pkgAcquire::URIEncode(FileName);
+	 QueueURI(Desc);
+	 return;
+      }
+
+      // Erase the file if it is a symlink so we can overwrite it
+      struct stat St;
+      if (lstat(DestFile.c_str(),&St) == 0)
+      {
+	 if (S_ISLNK(St.st_mode) != 0)
+	    RemoveFile("pkgAcqFile::Done", DestFile);
+      }
+
+      // Symlink the file
+      if (symlink(FileName.c_str(),DestFile.c_str()) != 0)
+      {
+	 _error->PushToStack();
+	 _error->Errno("pkgAcqFile::Done", "Symlinking file %s failed", DestFile.c_str());
+	 std::stringstream msg;
+	 _error->DumpErrors(msg, GlobalError::DEBUG, false);
+	 _error->RevertToStack();
+	 ErrorText = msg.str();
+	 Status = StatError;
+	 Complete = false;
+      }
+   }
+}
+									/*}}}*/
+string pkgAcqFile::Custom600Headers() const				/*{{{*/
+{
+   string Header = pkgAcquire::Item::Custom600Headers();
+   if (not IsIndexFile)
+      return Header;
+   return Header + "\nIndex-File: true";
+}
+									/*}}}*/
+pkgAcqFile::~pkgAcqFile() {}
+
+void pkgAcqAuxFile::Failed(std::string const &Message, pkgAcquire::MethodConfig const *const Cnf) /*{{{*/
+{
+   pkgAcqFile::Failed(Message, Cnf);
+   if (Status == StatIdle)
+      return;
+   if (RealFileExists(DestFile))
+      Rename(DestFile, DestFile + ".FAILED");
+   Worker->ReplyAux(Desc);
+}
+									/*}}}*/
+void pkgAcqAuxFile::Done(std::string const &Message, HashStringList const &CalcHashes, /*{{{*/
+			 pkgAcquire::MethodConfig const *const Cnf)
+{
+   pkgAcqFile::Done(Message, CalcHashes, Cnf);
+   if (Status == StatDone)
+      Worker->ReplyAux(Desc);
+   else if (Status == StatAuthError || Status == StatError)
+      Worker->ReplyAux(Desc);
+}
+									/*}}}*/
+std::string pkgAcqAuxFile::Custom600Headers() const /*{{{*/
+{
+   if (MaximumSize == 0)
+      return pkgAcqFile::Custom600Headers();
+   std::string maxsize;
+   strprintf(maxsize, "\nMaximum-Size: %llu", MaximumSize);
+   return pkgAcqFile::Custom600Headers().append(maxsize);
+}
+									/*}}}*/
+void pkgAcqAuxFile::Finished() /*{{{*/
+{
+   auto dirname = flCombine(_config->FindDir("Dir::State::lists"), "auxfiles/");
+   if (APT::String::Startswith(DestFile, dirname))
+   {
+      // the file is never returned by method requesting it, so fix up the permission now
+      if (FileExists(DestFile))
+      {
+	 ChangeOwnerAndPermissionOfFile("pkgAcqAuxFile", DestFile.c_str(), "root", ROOT_GROUP, 0644);
+	 if (Status == StatDone)
+	    return;
+      }
+   }
+   else
+   {
+      dirname = flNotFile(DestFile);
+      RemoveFile("pkgAcqAuxFile::Finished", DestFile);
+      RemoveFile("pkgAcqAuxFile::Finished", DestFile + ".FAILED");
+      rmdir(dirname.c_str());
+   }
+   DestFile.clear();
+}
+									/*}}}*/
+// GetAuxFileNameFromURI						/*{{{*/
+static std::string GetAuxFileNameFromURIInLists(std::string const &uri)
+{
+   // check if we have write permission for our usual location.
+   auto const dirname = flCombine(_config->FindDir("Dir::State::lists"), "auxfiles/");
+   char const * const filetag = ".apt-acquire-privs-test.XXXXXX";
+   std::string const tmpfile_tpl = flCombine(dirname, filetag);
+   std::unique_ptr<char, decltype(std::free) *> tmpfile { strdup(tmpfile_tpl.c_str()), std::free };
+   int const fd = mkstemp(tmpfile.get());
+   if (fd == -1)
+      return "";
+   RemoveFile("GetAuxFileNameFromURI", tmpfile.get());
+   close(fd);
+   return flCombine(dirname, URItoFileName(uri));
+}
+static std::string GetAuxFileNameFromURI(std::string const &uri)
+{
+   auto const lists = GetAuxFileNameFromURIInLists(uri);
+   if (lists.empty() == false)
+      return lists;
+
+   std::string tmpdir_tpl;
+   strprintf(tmpdir_tpl, "%s/apt-auxfiles-XXXXXX", GetTempDir().c_str());
+   std::unique_ptr<char, decltype(std::free) *> tmpdir { strndup(tmpdir_tpl.data(), tmpdir_tpl.length()), std::free };
+   if (mkdtemp(tmpdir.get()) == nullptr)
+   {
+      _error->Errno("GetAuxFileNameFromURI", "mkdtemp of %s failed", tmpdir.get());
+      return flCombine("/nonexistent/auxfiles/", URItoFileName(uri));
+   }
+   chmod(tmpdir.get(), 0755);
+   auto const filename = flCombine(tmpdir.get(), URItoFileName(uri));
+   _error->PushToStack();
+   FileFd in(flCombine(flCombine(_config->FindDir("Dir::State::lists"), "auxfiles/"), URItoFileName(uri)), FileFd::ReadOnly);
+   if (in.IsOpen())
+   {
+      FileFd out(filename, FileFd::WriteOnly | FileFd::Create | FileFd::Exclusive);
+      CopyFile(in, out);
+      ChangeOwnerAndPermissionOfFile("GetAuxFileNameFromURI", filename.c_str(), "root", ROOT_GROUP, 0644);
+   }
+   _error->RevertToStack();
+   return filename;
+}
+									/*}}}*/
+pkgAcqAuxFile::pkgAcqAuxFile(pkgAcquire::Item *const Owner, pkgAcquire::Worker *const Worker,
+			     std::string const &ShortDesc, std::string const &Desc, std::string const &URI,
+			     HashStringList const &Hashes, unsigned long long const MaximumSize) : pkgAcqFile(Owner->GetOwner(), URI, Hashes, Hashes.FileSize(), Desc, ShortDesc, "", GetAuxFileNameFromURI(URI), false),
+												   Owner(Owner), Worker(Worker), MaximumSize(MaximumSize)
+{
+   /* very bad failures can happen while constructing which causes
+      us to hang as the aux request is never answered (e.g. method not available)
+      Ideally we catch failures earlier, but a safe guard can't hurt. */
+   if (Status == pkgAcquire::Item::StatIdle || Status == pkgAcquire::Item::StatFetching)
+      return;
+   Failed(std::string("400 URI Failure\n") +
+	     "URI: " + URI + "\n" +
+	     "Filename: " + DestFile,
+	  nullptr);
+}
+pkgAcqAuxFile::~pkgAcqAuxFile() {}
diff --git a/apt-pkg/acquire-item.h b/apt-pkg/acquire-item.h
new file mode 100644
index 0000000..22da981
--- /dev/null
+++ b/apt-pkg/acquire-item.h
@@ -0,0 +1,1218 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Item - Item to acquire
+
+   When an item is instantiated it will add it self to the local list in
+   the Owner Acquire class. Derived classes will then call QueueURI to
+   register all the URI's they wish to fetch at the initial moment.
+
+   Three item classes are provided to provide functionality for
+   downloading of Index, Translation and Packages files.
+
+   A Archive class is provided for downloading .deb files. It does Hash
+   checking and source location as well as a retry algorithm.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ACQUIRE_ITEM_H
+#define PKGLIB_ACQUIRE_ITEM_H
+
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/weakptr.h>
+
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+
+/** \addtogroup acquire
+ *  @{
+ *
+ *  \file acquire-item.h
+ */
+
+class pkgRecords;
+class pkgSourceList;
+class pkgAcqMetaClearSig;
+class pkgAcqIndexMergeDiffs;
+class metaIndex;
+
+class APT_PUBLIC pkgAcquire::Item : public WeakPointable				/*{{{*/
+/** \brief Represents the process by which a pkgAcquire object should
+ *  retrieve a file or a collection of files.
+ *
+ *  By convention, Item subclasses should insert themselves into the
+ *  acquire queue when they are created by calling QueueURI(), and
+ *  remove themselves by calling Dequeue() when either Done() or
+ *  Failed() is invoked.  Item objects are also responsible for
+ *  notifying the download progress indicator (accessible via
+ *  #Owner->Log) of their status.
+ *
+ *  \see pkgAcquire
+ */
+{
+   public:
+
+   /** \brief The current status of this item. */
+   enum ItemState
+     {
+       /** \brief The item is waiting to be downloaded. */
+       StatIdle,
+
+       /** \brief The item is currently being downloaded. */
+       StatFetching,
+
+       /** \brief The item has been successfully downloaded. */
+       StatDone,
+
+       /** \brief An error was encountered while downloading this
+	*  item.
+	*/
+       StatError,
+
+       /** \brief The item was downloaded but its authenticity could
+	*  not be verified.
+	*/
+       StatAuthError,
+
+       /** \brief The item was could not be downloaded because of
+	*  a transient network error (e.g. network down)
+	*/
+       StatTransientNetworkError,
+     } Status;
+
+   /** \brief Contains a textual description of the error encountered
+    *  if #ItemState is #StatError or #StatAuthError.
+    */
+   std::string ErrorText;
+
+   /** \brief The size of the object to fetch. */
+   unsigned long long FileSize;
+
+   /** \brief How much of the object was already fetched. */
+   unsigned long long PartialSize;
+
+   /** \brief contains the name of the subprocess that is operating on this object
+    * (for instance, "gzip", "rred" or "gpgv"). This is obsoleting #Mode from above
+    * as it can manage the lifetime of included string properly. */
+   std::string ActiveSubprocess;
+
+   /** \brief A client-supplied unique identifier.
+    *
+    *  This field is initialized to 0; it is meant to be filled in by
+    *  clients that wish to use it to uniquely identify items.
+    *
+    *  APT progress reporting will store an ID there as shown in "Get:42 …"
+    */
+   unsigned long ID;
+
+   /** \brief If \b true, the entire object has been successfully fetched.
+    *
+    *  Subclasses should set this to \b true when appropriate.
+    */
+   bool Complete;
+
+   /** \brief If \b true, the URI of this object is "local".
+    *
+    *  The only effect of this field is to exclude the object from the
+    *  download progress indicator's overall statistics.
+    */
+   bool Local;
+
+   std::string UsedMirror;
+
+   /** \brief The number of fetch queues into which this item has been
+    *  inserted.
+    *
+    *  There is one queue for each source from which an item could be
+    *  downloaded.
+    *
+    *  \sa pkgAcquire
+    */
+   unsigned int QueueCounter;
+
+   /** \brief The number of additional fetch items that are expected
+    *  once this item is done.
+    *
+    *  Some items like pkgAcqMeta{Index,Sig} will queue additional
+    *  items. This variable can be set by the methods if it knows
+    *  in advance how many items to expect to get a more accurate
+    *  progress.
+    */
+   unsigned int ExpectedAdditionalItems;
+
+   /** \brief The name of the file into which the retrieved object
+    *  will be written.
+    */
+   std::string DestFile;
+
+   /** \brief Number of retries */
+   unsigned int Retries;
+
+   /** \brief Invoked by the acquire worker when the object couldn't
+    *  be fetched.
+    *
+    *  This is a branch of the continuation of the fetch process.
+    *
+    *  \param Message An RFC822-formatted message from the acquire
+    *  method describing what went wrong.  Use LookupTag() to parse
+    *  it.
+    *
+    *  \param Cnf The method via which the worker tried to fetch this object.
+    *
+    *  \sa pkgAcqMethod
+    */
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf);
+   APT_HIDDEN void FailMessage(std::string const &Message);
+
+   /** \brief Invoked by the acquire worker to check if the successfully
+    * fetched object is also the objected we wanted to have.
+    *
+    *  Note that the object might \e not have been written to
+    *  DestFile; check for the presence of an Alt-Filename entry in
+    *  Message to find the file to which it was really written.
+    *
+    *  This is called before Done is called and can prevent it by returning
+    *  \b false which will result in Failed being called instead.
+    *
+    *  You should prefer to use this method over calling Failed() from Done()
+    *  as this has e.g. the wrong progress reporting.
+    *
+    *  \param Message Data from the acquire method.  Use LookupTag()
+    *  to parse it.
+    *  \param Cnf The method via which the object was fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
+   virtual bool VerifyDone(std::string const &Message,
+	 pkgAcquire::MethodConfig const * const Cnf);
+
+   /** \brief Invoked by the acquire worker when the object was
+    *  fetched successfully.
+    *
+    *  Note that the object might \e not have been written to
+    *  DestFile; check for the presence of an Alt-Filename entry in
+    *  Message to find the file to which it was really written.
+    *
+    *  Done is often used to switch from one stage of the processing
+    *  to the next (e.g. fetching, unpacking, copying).  It is one
+    *  branch of the continuation of the fetch process.
+    *
+    *  \param Message Data from the acquire method.  Use LookupTag()
+    *  to parse it.
+    *  \param Hashes The HashSums of the object that was fetched.
+    *  \param Cnf The method via which the object was fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf);
+
+   /** \brief Invoked when the worker starts to fetch this object.
+    *
+    *  \param Message RFC822-formatted data from the worker process.
+    *  Use LookupTag() to parse it.
+    *
+    *  \param Hashes The expected hashes of the object being fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
+   virtual void Start(std::string const &Message, unsigned long long const Size);
+
+   /** \brief Custom headers to be sent to the fetch process.
+    *
+    *  \return a string containing RFC822-style headers that are to be
+    *  inserted into the 600 URI Acquire message sent to the fetch
+    *  subprocess.  The headers are inserted after a newline-less
+    *  line, so they should (if nonempty) have a leading newline and
+    *  no trailing newline.
+    */
+   virtual std::string Custom600Headers() const;
+   // this is more a hack than a proper external interface, hence hidden
+   APT_HIDDEN std::unordered_map<std::string, std::string> &ModifyCustomFields();
+   // this isn't the super nicest interface either…
+   APT_HIDDEN bool PopAlternativeURI(std::string &NewURI);
+   APT_HIDDEN bool IsGoodAlternativeURI(std::string const &AltUri) const;
+   APT_HIDDEN void PushAlternativeURI(std::string &&NewURI, std::unordered_map<std::string, std::string> &&fields, bool const at_the_back);
+   APT_HIDDEN void RemoveAlternativeSite(std::string &&OldSite);
+
+   /** \brief A "descriptive" URI-like string.
+    *
+    *  \return a URI that should be used to describe what is being fetched.
+    */
+   virtual std::string DescURI() const = 0;
+   /** \brief Short item description.
+    *
+    *  \return a brief description of the object being fetched.
+    */
+   virtual std::string ShortDesc() const;
+
+   /** \brief Invoked by the worker when the download is completely done. */
+   virtual void Finished();
+
+   /** \return HashSums the DestFile is supposed to have in this stage */
+   virtual HashStringList GetExpectedHashes() const = 0;
+   /** \return the 'best' hash for display proposes like --print-uris */
+   std::string HashSum() const;
+
+   /** \return if having no hashes is a hard failure or not
+    *
+    * Idealy this is always \b true for every subclass, but thanks to
+    * historical grow we don't have hashes for all files in all cases
+    * in all steps, so it is slightly more complicated than it should be.
+    */
+   virtual bool HashesRequired() const { return true; }
+
+   /** \return the acquire process with which this item is associated. */
+   pkgAcquire *GetOwner() const;
+   pkgAcquire::ItemDesc &GetItemDesc();
+
+   /** \return \b true if this object is being fetched from a trusted source. */
+   virtual bool IsTrusted() const;
+
+   /** \brief Set the name of the current active subprocess
+    *
+    *  See also #ActiveSubprocess
+    */
+   void SetActiveSubprocess(std::string const &subprocess);
+
+   /** \brief Initialize an item.
+    *
+    *  Adds the item to the list of items known to the acquire
+    *  process, but does not place it into any fetch queues (you must
+    *  manually invoke QueueURI() to do so).
+    *
+    *  \param Owner The new owner of this item.
+    */
+   explicit Item(pkgAcquire * const Owner);
+
+   /** \brief Remove this item from its owner's queue by invoking
+    *  pkgAcquire::Remove.
+    */
+   virtual ~Item();
+
+   bool APT_HIDDEN IsRedirectionLoop(std::string const &NewURI);
+   /** \brief The priority of the item, used for queuing */
+   int APT_HIDDEN Priority();
+
+   /** \brief internal clock definitions to avoid typing all that all over the place */
+   void APT_HIDDEN FetchAfter(time_point FetchAfter);
+   time_point APT_HIDDEN FetchAfter();
+
+   protected:
+   /** \brief The acquire object with which this item is associated. */
+   pkgAcquire * const Owner;
+
+   /** \brief The item that is currently being downloaded. */
+   pkgAcquire::ItemDesc Desc;
+
+   enum RenameOnErrorState {
+      HashSumMismatch,
+      SizeMismatch,
+      InvalidFormat,
+      SignatureError,
+      NotClearsigned,
+      MaximumSizeExceeded,
+      PDiffError,
+   };
+
+   /** \brief Rename failed file and set error
+    *
+    * \param state respresenting the error we encountered
+    */
+   bool RenameOnError(RenameOnErrorState const state);
+
+   /** \brief Insert this item into its owner's queue.
+    *
+    *  The method is designed to check if the request would end
+    *  in an IMSHit and if it determines that it would, it isn't
+    *  queueing the Item and instead sets it to completion instantly.
+    *
+    *  \param Item Metadata about this item (its URI and
+    *  description).
+    *  \return true if the item was inserted, false if IMSHit was detected
+    */
+   virtual bool QueueURI(ItemDesc &Item);
+
+   /** \brief Remove this item from its owner's queue. */
+   void Dequeue();
+
+   /** \brief Rename a file without modifying its timestamp.
+    *
+    *  Many item methods call this as their final action.
+    *
+    *  \param From The file to be renamed.
+    *
+    *  \param To The new name of \a From.  If \a To exists it will be
+    *  overwritten. If \a From and \a To are equal nothing happens.
+    */
+   bool Rename(std::string const &From, std::string const &To);
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const;
+
+   private:
+   class Private;
+   Private * const d;
+
+   friend class pkgAcqMetaBase;
+   friend class pkgAcqMetaClearSig;
+};
+									/*}}}*/
+class APT_HIDDEN pkgAcqTransactionItem: public pkgAcquire::Item		/*{{{*/
+/** \brief baseclass for the indexes files to manage them all together */
+{
+   void * const d;
+   protected:
+   HashStringList GetExpectedHashesFor(std::string const &MetaKey) const;
+
+   bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+
+   public:
+   IndexTarget const Target;
+
+   /** \brief storge name until a transaction is finished */
+   std::string PartialFile;
+
+   /** \brief TransactionManager */
+   pkgAcqMetaClearSig * const TransactionManager;
+
+   enum TransactionStates {
+      TransactionStarted,
+      TransactionCommit,
+      TransactionAbort,
+   };
+   virtual bool TransactionState(TransactionStates const state);
+
+   virtual std::string DescURI() const APT_OVERRIDE { return Target.URI; }
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual std::string GetMetaKey() const;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+   virtual bool AcquireByHash() const;
+
+   pkgAcqTransactionItem(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager, IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqTransactionItem();
+
+   friend class pkgAcqMetaBase;
+   friend class pkgAcqMetaClearSig;
+};
+									/*}}}*/
+class APT_HIDDEN pkgAcqMetaBase : public pkgAcqTransactionItem		/*{{{*/
+/** \brief the manager of a transaction */
+{
+   void * const d;
+ protected:
+   std::vector<pkgAcqTransactionItem*> Transaction;
+
+   /** \brief If \b true, the index's signature is currently being verified.
+    */
+   bool AuthPass;
+
+   /** \brief Called when a file is finished being retrieved.
+    *
+    *  If the file was not downloaded to DestFile, a copy process is
+    *  set up to copy it to DestFile; otherwise, Complete is set to \b
+    *  true and the file is moved to its final location.
+    *
+    *  \param Message The message block received from the fetch
+    *  subprocess.
+    */
+   bool CheckDownloadDone(pkgAcqTransactionItem * const I, const std::string &Message, HashStringList const &Hashes) const;
+
+   /** \brief Queue the downloaded Signature for verification */
+   void QueueForSignatureVerify(pkgAcqTransactionItem * const I, std::string const &File, std::string const &Signature);
+
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+
+   /** \brief Called when authentication succeeded.
+    *
+    *  Sanity-checks the authenticated file, queues up the individual
+    *  index files for download, and saves the signature in the lists
+    *  directory next to the authenticated list file.
+    *
+    *  \param Message The message block received from the fetch
+    *  subprocess.
+    *  \param Cnf The method and its configuration which handled the request
+    */
+   bool CheckAuthDone(std::string const &Message, pkgAcquire::MethodConfig const *const Cnf);
+
+   /** Check if the current item should fail at this point */
+   bool CheckStopAuthentication(pkgAcquire::Item * const I, const std::string &Message);
+
+   /** \brief Check that the release file is a release file for the
+    *  correct distribution.
+    *
+    *  \return \b true if no fatal errors were encountered.
+    */
+   bool VerifyVendor(std::string const &Message);
+
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
+
+ public:
+   // This refers more to the Transaction-Manager than the actual file
+   bool IMSHit;
+   TransactionStates State;
+   std::string BaseURI;
+
+   virtual bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+   // transaction code
+   void Add(pkgAcqTransactionItem * const I);
+   void AbortTransaction();
+   bool TransactionHasError() const;
+   void CommitTransaction();
+
+   /** \brief Stage (queue) a copy action when the transaction is committed
+    */
+   void TransactionStageCopy(pkgAcqTransactionItem * const I,
+                             const std::string &From,
+                             const std::string &To);
+   /** \brief Stage (queue) a removal action when the transaction is committed
+    */
+   void TransactionStageRemoval(pkgAcqTransactionItem * const I, const std::string &FinalFile);
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   pkgAcqMetaBase(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+		  IndexTarget const &DataTarget) APT_NONNULL(2, 3);
+   virtual ~pkgAcqMetaBase();
+};
+									/*}}}*/
+/** \brief An item that is responsible for downloading the meta-index	{{{
+ *  file (i.e., Release) itself and verifying its signature.
+ *
+ *  Once the download and verification are complete, the downloads of
+ *  the individual index files are queued up using pkgAcqDiffIndex.
+ *  If the meta-index file had a valid signature, the expected hashsums
+ *  of the index files will be the md5sums listed in the meta-index;
+ *  otherwise, the expected hashsums will be "" (causing the
+ *  authentication of the index files to be bypassed).
+ */
+class APT_HIDDEN pkgAcqMetaIndex : public pkgAcqMetaBase
+{
+   void * const d;
+   protected:
+   IndexTarget const DetachedSigTarget;
+
+   /** \brief delayed constructor */
+   void Init(std::string const &URIDesc, std::string const &ShortDesc);
+
+   public:
+   virtual std::string DescURI() const APT_OVERRIDE;
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqMetaIndex. */
+   pkgAcqMetaIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+		   IndexTarget const &DataTarget, IndexTarget const &DetachedSigTarget) APT_NONNULL(2, 3);
+   virtual ~pkgAcqMetaIndex();
+
+   friend class pkgAcqMetaSig;
+};
+									/*}}}*/
+/** \brief An acquire item that downloads the detached signature	{{{
+ *  of a meta-index (Release) file, then queues up the release
+ *  file itself.
+ *
+ *  \todo Why protected members?
+ *
+ *  \sa pkgAcqMetaIndex
+ */
+class APT_HIDDEN pkgAcqMetaSig : public pkgAcqTransactionItem
+{
+   void * const d;
+
+   pkgAcqMetaIndex * const MetaIndex;
+
+   /** \brief The file we use to verify the MetaIndexFile with (not always set!) */
+   std::string MetaIndexFileSignature;
+
+   protected:
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   public:
+   virtual bool HashesRequired() const APT_OVERRIDE { return false; }
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqMetaSig. */
+   pkgAcqMetaSig(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+	 IndexTarget const &Target, pkgAcqMetaIndex * const MetaIndex) APT_NONNULL(2, 3, 5);
+   virtual ~pkgAcqMetaSig();
+};
+									/*}}}*/
+/** \brief An item responsible for downloading clearsigned metaindexes	{{{*/
+class APT_HIDDEN pkgAcqMetaClearSig : public pkgAcqMetaIndex
+{
+   void * const d;
+   IndexTarget const DetachedDataTarget;
+
+ public:
+   /** \brief A package-system-specific parser for the meta-index file. */
+   metaIndex *MetaIndexParser;
+   metaIndex *LastMetaIndexParser;
+
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual bool VerifyDone(std::string const &Message, pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Finished() APT_OVERRIDE;
+
+   /** \brief Starts downloading the individual index files.
+    *
+    *  \param verify If \b true, only indices whose expected hashsum
+    *  can be determined from the meta-index will be downloaded, and
+    *  the hashsums of indices will be checked (reporting
+    *  #StatAuthError if there is a mismatch).  If verify is \b false,
+    *  no hashsum checking will be performed.
+    */
+   void QueueIndexes(bool const verify);
+
+   /** \brief Create a new pkgAcqMetaClearSig. */
+   pkgAcqMetaClearSig(pkgAcquire * const Owner,
+		IndexTarget const &ClearsignedTarget,
+		IndexTarget const &DetachedDataTarget,
+		IndexTarget const &DetachedSigTarget,
+		metaIndex * const MetaIndexParser);
+   virtual ~pkgAcqMetaClearSig();
+};
+									/*}}}*/
+/** \brief Common base class for all classes that deal with fetching indexes	{{{*/
+class APT_HIDDEN pkgAcqBaseIndex : public pkgAcqTransactionItem
+{
+   void * const d;
+
+ public:
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+
+   pkgAcqBaseIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                   IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqBaseIndex();
+};
+									/*}}}*/
+/** \brief An acquire item that is responsible for fetching an index	{{{
+ *  file (e.g., Packages or Sources).
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndexDiffs, pkgAcqIndexTrans
+ *
+ *  \todo Why does pkgAcqIndex have protected members?
+ */
+class APT_HIDDEN pkgAcqIndex : public pkgAcqBaseIndex
+{
+   void * const d;
+
+   protected:
+
+   /** \brief The stages the method goes through
+    *
+    *  The method first downloads the indexfile, then its decompressed (or
+    *  copied) and verified
+    */
+   enum AllStages {
+      STAGE_DOWNLOAD,
+      STAGE_DECOMPRESS_AND_VERIFY,
+   };
+   AllStages Stage;
+
+   /** \brief Handle what needs to be done when the download is done */
+   void StageDownloadDone(std::string const &Message);
+
+   /** \brief Handle what needs to be done when the decompression/copy is
+    *         done
+    */
+   void StageDecompressDone();
+
+   /** \brief If \b set, this partially downloaded file will be
+    *  removed when the download completes.
+    */
+   std::string EraseFileName;
+
+   /** \brief The compression-related file extensions that are being
+    *  added to the downloaded file one by one if first fails (e.g., "gz bz2").
+    */
+   std::string CompressionExtensions;
+
+   /** \brief The actual compression extension currently used */
+   std::string CurrentCompressionExtension;
+
+   /** \brief Do the changes needed to fetch via AptByHash (if needed) */
+   void InitByHashIfNeeded();
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
+
+   public:
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+   virtual std::string GetMetaKey() const APT_OVERRIDE;
+
+   pkgAcqIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+               IndexTarget const &Target, bool const Derived = false) APT_NONNULL(2, 3);
+   virtual ~pkgAcqIndex();
+
+   protected:
+   APT_HIDDEN void Init(std::string const &URI, std::string const &URIDesc,
+             std::string const &ShortDesc);
+   APT_HIDDEN bool CommonFailed(std::string const &TargetURI,
+				std::string const &Message, pkgAcquire::MethodConfig const *const Cnf);
+};
+									/*}}}*/
+struct APT_HIDDEN DiffInfo {						/*{{{*/
+   /** The filename of the diff. */
+   std::string file;
+
+   /** The hashes of the file after the diff is applied */
+   HashStringList result_hashes;
+
+   /** The hashes of the diff */
+   HashStringList patch_hashes;
+
+   /** The hashes of the compressed diff */
+   HashStringList download_hashes;
+};
+									/*}}}*/
+/** \brief An item that is responsible for fetching an index file of	{{{
+ *  package list diffs and starting the package list's download.
+ *
+ *  This item downloads the Index file and parses it, then enqueues
+ *  additional downloads of either the individual patches (using
+ *  pkgAcqIndexDiffs) or the entire Packages file (using pkgAcqIndex).
+ *
+ *  \sa pkgAcqIndexDiffs, pkgAcqIndex
+ */
+class APT_HIDDEN pkgAcqDiffIndex : public pkgAcqIndex
+{
+   void * const d;
+   std::vector<pkgAcqIndexMergeDiffs*> * diffs;
+   std::vector<DiffInfo> available_patches;
+   bool pdiff_merge;
+
+ protected:
+   /** \brief If \b true, debugging information will be written to std::clog. */
+   bool Debug;
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   virtual bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
+ public:
+   // Specialized action members
+   virtual void Failed(std::string const &Message, pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual bool VerifyDone(std::string const &Message, pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "Index";};
+   virtual std::string GetMetaKey() const APT_OVERRIDE;
+
+   /** \brief Parse the Index file for a set of Packages diffs.
+    *
+    *  Parses the Index file and creates additional download items as
+    *  necessary.
+    *
+    *  \param IndexDiffFile The name of the Index file.
+    *
+    *  \return \b true if the Index file was successfully parsed, \b
+    *  false otherwise.
+    */
+   bool ParseDiffIndex(std::string const &IndexDiffFile);
+
+   /** \brief Create a new pkgAcqDiffIndex.
+    *
+    *  \param Owner The Acquire object that owns this item.
+    *
+    *  \param URI The URI of the list file to download.
+    *
+    *  \param URIDesc A long description of the list file to download.
+    *
+    *  \param ShortDesc A short description of the list file to download.
+    */
+   pkgAcqDiffIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                   IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqDiffIndex();
+ private:
+   APT_HIDDEN void QueueOnIMSHit() const;
+};
+									/*}}}*/
+/** \brief An item that is responsible for fetching client-merge patches {{{
+ *  that need to be applied to a given package index file.
+ *
+ *  Instead of downloading and applying each patch one by one like its
+ *  sister #pkgAcqIndexDiffs this class will download all patches at once
+ *  and call rred with all the patches downloaded once. Rred will then
+ *  merge and apply them in one go, which should be a lot faster – but is
+ *  incompatible with server-based merges of patches like reprepro can do.
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndex
+ */
+class APT_HIDDEN pkgAcqIndexMergeDiffs : public pkgAcqBaseIndex
+{
+   protected:
+
+   /** \brief If \b true, debugging output will be written to
+    *  std::clog.
+    */
+   bool Debug;
+
+   /** \brief information about the current patch */
+   struct DiffInfo const patch;
+
+   /** \brief list of all download items for the patches */
+   std::vector<pkgAcqIndexMergeDiffs*> const * const allPatches;
+
+   /** The current status of this patch. */
+   enum DiffState
+   {
+      /** \brief The diff is currently being fetched. */
+      StateFetchDiff,
+
+      /** \brief The diff is currently being applied. */
+      StateApplyDiff,
+
+      /** \brief the work with this diff is done */
+      StateDoneDiff,
+
+      /** \brief something bad happened and fallback was triggered */
+      StateErrorDiff
+   } State;
+
+   public:
+   /** \brief Called when the patch file failed to be downloaded.
+    *
+    *  This method will fall back to downloading the whole index file
+    *  outright; its arguments are ignored.
+    */
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+	 pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "Index";};
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+   virtual bool AcquireByHash() const APT_OVERRIDE;
+
+   /** \brief Create an index merge-diff item.
+    *
+    *  \param Owner The pkgAcquire object that owns this item.
+    *  \param TransactionManager responsible for this item
+    *  \param Target we intend to built via pdiff patching
+    *  \param baseURI is the URI used for the Index, but stripped down to Target
+    *  \param DiffInfo of the patch in question
+    *  \param patch contains infos about the patch this item is supposed
+    *  to download which were read from the index
+    *  \param allPatches contains all related items so that each item can
+    *  check if it was the last one to complete the download step
+    */
+   pkgAcqIndexMergeDiffs(pkgAcquire *const Owner, pkgAcqMetaClearSig *const TransactionManager,
+			 IndexTarget const &Target, DiffInfo const &patch,
+			 std::vector<pkgAcqIndexMergeDiffs *> const *const allPatches) APT_NONNULL(2, 3, 6);
+   virtual ~pkgAcqIndexMergeDiffs();
+};
+									/*}}}*/
+/** \brief An item that is responsible for fetching server-merge patches {{{
+ *  that need to be applied to a given package index file.
+ *
+ *  After downloading and applying a single patch, this item will
+ *  enqueue a new pkgAcqIndexDiffs to download and apply the remaining
+ *  patches.  If no patch can be found that applies to an intermediate
+ *  file or if one of the patches cannot be downloaded, falls back to
+ *  downloading the entire package index file using pkgAcqIndex.
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndex
+ */
+class APT_HIDDEN pkgAcqIndexDiffs : public pkgAcqBaseIndex
+{
+   private:
+
+   /** \brief Queue up the next diff download.
+    *
+    *  Search for the next available diff that applies to the file
+    *  that currently exists on disk, and enqueue it by calling
+    *  QueueURI().
+    *
+    *  \return \b true if an applicable diff was found, \b false
+    *  otherwise.
+    */
+   APT_HIDDEN bool QueueNextDiff();
+
+   /** \brief Handle tasks that must be performed after the item
+    *  finishes downloading.
+    *
+    *  Dequeues the item and checks the resulting file's hashsums
+    *  against ExpectedHashes after the last patch was applied.
+    *  There is no need to check the md5/sha1 after a "normal" 
+    *  patch because QueueNextDiff() will check the sha1 later.
+    *
+    *  \param allDone If \b true, the file was entirely reconstructed,
+    *  and its md5sum is verified. 
+    */
+   APT_HIDDEN void Finish(bool const allDone=false);
+
+   protected:
+
+   /** \brief If \b true, debugging output will be written to
+    *  std::clog.
+    */
+   bool Debug;
+
+   /** The patches that remain to be downloaded, including the patch
+    *  being downloaded right now.  This list should be ordered so
+    *  that each diff appears before any diff that depends on it.
+    *
+    *  \todo These are indexed by sha1sum; why not use some sort of
+    *  dictionary instead of relying on ordering and stripping them
+    *  off the front?
+    */
+   std::vector<DiffInfo> available_patches;
+
+   /** The current status of this patch. */
+   enum DiffState
+   {
+	 /** \brief The diff is currently being fetched. */
+	 StateFetchDiff,
+
+	 /** \brief The diff is currently being applied. */
+	 StateApplyDiff
+   } State;
+
+   public:
+
+   /** \brief Called when the patch file failed to be downloaded.
+    *
+    *  This method will fall back to downloading the whole index file
+    *  outright; its arguments are ignored.
+    */
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "IndexDiffs";};
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+   virtual bool AcquireByHash() const APT_OVERRIDE;
+
+   /** \brief Create an index diff item.
+    *
+    *  After filling in its basic fields, this invokes Finish(true) if
+    *  \a diffs is empty, or QueueNextDiff() otherwise.
+    *
+    *  \param Owner The pkgAcquire object that owns this item.
+    *  \param TransactionManager responsible for this item
+    *  \param Target we want to built via pdiff patching
+    *  \param baseURI is the URI used for the Index, but stripped down to Target
+    *  \param diffs The remaining diffs from the index of diffs.  They
+    *  should be ordered so that each diff appears before any diff
+    *  that depends on it.
+    */
+   pkgAcqIndexDiffs(pkgAcquire *const Owner, pkgAcqMetaClearSig *const TransactionManager,
+		    IndexTarget const &Target,
+		    std::vector<DiffInfo> const &diffs = std::vector<DiffInfo>()) APT_NONNULL(2, 3);
+   virtual ~pkgAcqIndexDiffs();
+};
+									/*}}}*/
+/** \brief An item that is responsible for fetching a package file.	{{{
+ *
+ *  If the package file already exists in the cache, nothing will be
+ *  done.
+ */
+class APT_PUBLIC pkgAcqArchive : public pkgAcquire::Item
+{
+   void * const d;
+
+   bool LocalSource;
+   HashStringList ExpectedHashes;
+
+   protected:
+   /** \brief The package version being fetched. */
+   pkgCache::VerIterator Version;
+
+   /** \brief The list of sources from which to pick archives to
+    *  download this package from.
+    */
+   pkgSourceList *Sources;
+
+   /** \brief A package records object, used to look up the file
+    *  corresponding to each version of the package.
+    */
+   pkgRecords *Recs;
+
+   /** \brief A location in which the actual filename of the package
+    *  should be stored.
+    */
+   std::string &StoreFilename;
+
+   /** \brief \b true if this version file is being downloaded from a
+    *  trusted source.
+    */
+   bool Trusted;
+
+   /** \brief Queue up the next available file for this version. */
+   bool QueueNext();
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   public:
+
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE;
+   virtual std::string ShortDesc() const APT_OVERRIDE;
+   virtual void Finished() APT_OVERRIDE;
+   virtual bool IsTrusted() const APT_OVERRIDE;
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqArchive.
+    *
+    *  \param Owner The pkgAcquire object with which this item is
+    *  associated.
+    *
+    *  \param Sources The sources from which to download version
+    *  files.
+    *
+    *  \param Recs A package records object, used to look up the file
+    *  corresponding to each version of the package.
+    *
+    *  \param Version The package version to download.
+    *
+    *  \param[out] StoreFilename A location in which the actual filename of
+    *  the package should be stored.  It will be set to a guessed
+    *  basename in the constructor, and filled in with a fully
+    *  qualified filename once the download finishes.
+    */
+   pkgAcqArchive(pkgAcquire * const Owner,pkgSourceList * const Sources,
+		 pkgRecords * const Recs,pkgCache::VerIterator const &Version,
+		 std::string &StoreFilename);
+   virtual ~pkgAcqArchive();
+};
+									/*}}}*/
+/** \brief Retrieve the changelog for the given version			{{{
+ *
+ *  Downloads the changelog to a temporary file it will also remove again
+ *  while it is deconstructed or downloads it to a named location.
+ */
+class APT_PUBLIC pkgAcqChangelog : public pkgAcquire::Item
+{
+   class Private;
+   Private * const d;
+   std::string TemporaryDirectory;
+   std::string const SrcName;
+   std::string const SrcVersion;
+
+   public:
+   // we will never have hashes for changelogs.
+   // If you need verified ones, download the deb and extract the changelog.
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE { return HashStringList(); }
+   virtual bool HashesRequired() const APT_OVERRIDE { return false; }
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &CalcHashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+
+   /** returns the URI to the changelog of this version
+    *
+    * @param Ver is the version to get the changelog for
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(pkgCache::VerIterator const &Ver);
+
+   /** returns the URI to the changelog of this version
+    *
+    *  \param Rls is the Release file the package comes from
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(pkgCache::RlsFileIterator const &Rls,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion);
+
+   /** returns the URI to the changelog of this version
+    *
+    *  \param Template URI where @CHANGEPATH@ has to be filled in
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(std::string const &Template,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion);
+
+   /** returns the URI template for this release file
+    *
+    *  \param Rls is a Release file
+    * @return the URI template to use for this release file
+    */
+   static std::string URITemplate(pkgCache::RlsFileIterator const &Rls);
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param Ver is the version to get the changelog for
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::VerIterator const &Ver,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param Rls is the Release file the package comes from
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::RlsFileIterator const &Rls,
+	 char const * const Component, char const * const SrcName, char const * const SrcVersion,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param URI is to be used to get the changelog
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, std::string const &URI,
+	 char const * const SrcName, char const * const SrcVersion,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   virtual ~pkgAcqChangelog();
+
+private:
+   APT_HIDDEN void Init(std::string const &DestDir, std::string const &DestFilename);
+};
+									/*}}}*/
+/** \brief Retrieve an arbitrary file to the current directory.		{{{
+ *
+ *  The file is retrieved even if it is accessed via a URL type that
+ *  normally is a NOP, such as "file".  If the download fails, the
+ *  partial file is renamed to get a ".FAILED" extension.
+ */
+class APT_PUBLIC pkgAcqFile : public pkgAcquire::Item
+{
+   void * const d;
+
+   /** \brief Should this file be considered a index file */
+   bool IsIndexFile;
+
+   HashStringList const ExpectedHashes;
+   public:
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+   // Specialized action members
+   virtual void Done(std::string const &Message, HashStringList const &CalcHashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqFile object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *
+    *  \param URI The URI to download.
+    *
+    *  \param Hashes The hashsums of the file to download, if they are known;
+    *  otherwise empty list.
+    *
+    *  \param Size The size of the file to download, if it is known;
+    *  otherwise 0.
+    *
+    *  \param Desc A description of the file being downloaded.
+    *
+    *  \param ShortDesc A brief description of the file being
+    *  downloaded.
+    *
+    *  \param DestDir The directory the file should be downloaded into.
+    *
+    *  \param DestFilename The filename+path the file is downloaded to.
+    *
+    *  \param IsIndexFile The file is considered a IndexFile and cache-control
+    *                     headers like "cache-control: max-age=0" are send
+    *
+    * If DestFilename is empty, download to DestDir/\<basename\> if
+    * DestDir is non-empty, $CWD/\<basename\> otherwise.  If
+    * DestFilename is NOT empty, DestDir is ignored and DestFilename
+    * is the absolute name to which the file should be downloaded.
+    */
+
+   pkgAcqFile(pkgAcquire * const Owner, std::string const &URI, HashStringList const &Hashes, unsigned long long const Size,
+	      std::string const &Desc, std::string const &ShortDesc,
+	      std::string const &DestDir="", std::string const &DestFilename="",
+	      bool const IsIndexFile=false);
+   virtual ~pkgAcqFile();
+};
+									/*}}}*/
+class APT_HIDDEN pkgAcqAuxFile : public pkgAcqFile /*{{{*/
+{
+   pkgAcquire::Item *const Owner;
+   pkgAcquire::Worker *const Worker;
+   unsigned long long MaximumSize;
+
+   public:
+   virtual void Failed(std::string const &Message, pkgAcquire::MethodConfig const *const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &CalcHashes,
+		     pkgAcquire::MethodConfig const *const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual void Finished() APT_OVERRIDE;
+
+   pkgAcqAuxFile(pkgAcquire::Item *const Owner, pkgAcquire::Worker *const Worker,
+		 std::string const &ShortDesc, std::string const &Desc, std::string const &URI,
+		 HashStringList const &Hashes, unsigned long long const MaximumSize);
+   virtual ~pkgAcqAuxFile();
+};
+									/*}}}*/
+/** @} */
+
+#endif
diff --git a/apt-pkg/acquire-method.cc b/apt-pkg/acquire-method.cc
new file mode 100644
index 0000000..0895825
--- /dev/null
+++ b/apt-pkg/acquire-method.cc
@@ -0,0 +1,600 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Method
+
+   This is a skeleton class that implements most of the functionality
+   of a method and some useful functions to make method implementation
+   simpler. The methods all derive this and specialize it. The most
+   complex implementation is the http method which needs to provide
+   pipelining, it runs the message engine at the same time it is 
+   downloading files..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-method.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <iterator>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+									/*}}}*/
+
+using namespace std;
+
+// poor mans unordered_map::try_emplace for C++11 as it is a C++17 feature /*{{{*/
+template <typename Arg>
+static void try_emplace(std::unordered_map<std::string, std::string> &fields, std::string &&name, Arg &&value)
+{
+   if (fields.find(name) == fields.end())
+      fields.emplace(std::move(name), std::forward<Arg>(value));
+}
+									/*}}}*/
+
+// AcqMethod::pkgAcqMethod - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* This constructs the initialization text */
+pkgAcqMethod::pkgAcqMethod(const char *Ver,unsigned long Flags)
+{
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "Version", Ver);
+   if ((Flags & SingleInstance) == SingleInstance)
+      try_emplace(fields, "Single-Instance", "true");
+
+   if ((Flags & Pipeline) == Pipeline)
+      try_emplace(fields, "Pipeline", "true");
+
+   if ((Flags & SendConfig) == SendConfig)
+      try_emplace(fields, "Send-Config", "true");
+
+   if ((Flags & LocalOnly) == LocalOnly)
+      try_emplace(fields, "Local-Only", "true");
+
+   if ((Flags & NeedsCleanup) == NeedsCleanup)
+      try_emplace(fields, "Needs-Cleanup", "true");
+
+   if ((Flags & Removable) == Removable)
+      try_emplace(fields, "Removable", "true");
+
+   if ((Flags & AuxRequests) == AuxRequests)
+      try_emplace(fields, "AuxRequests", "true");
+
+   if ((Flags & SendURIEncoded) == SendURIEncoded)
+      try_emplace(fields, "Send-URI-Encoded", "true");
+
+   SendMessage("100 Capabilities", std::move(fields));
+
+   SetNonBlock(STDIN_FILENO,true);
+
+   Queue = 0;
+   QueueBack = 0;
+}
+									/*}}}*/
+void pkgAcqMethod::SendMessage(std::string const &header, std::unordered_map<std::string, std::string> &&fields) /*{{{*/
+{
+   auto CheckKey = [](std::string const &str) {
+      // Space, hyphen-minus, and alphanum are allowed for keys/headers.
+      return str.find_first_not_of(" -0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz") == std::string::npos;
+   };
+
+   auto CheckValue = [](std::string const &str) {
+      return std::all_of(str.begin(), str.end(), [](unsigned char c) -> bool {
+	 return c > 127			   // unicode
+		|| (c > 31 && c < 127)     // printable chars
+		|| c == '\n' || c == '\t'; // special whitespace
+      });
+   };
+
+   auto Error = [this]() {
+      _error->Error("SECURITY: Message contains control characters, rejecting.");
+      _error->DumpErrors();
+      SendMessage("400 URI Failure", {{"URI", "<UNKNOWN>"}, {"Message", "SECURITY: Message contains control characters, rejecting."}});
+      abort();
+   };
+
+   if (!CheckKey(header))
+      return Error();
+
+   for (auto const &f : fields)
+   {
+      if (!CheckKey(f.first))
+	 return Error();
+      if (!CheckValue(f.second))
+	 return Error();
+   }
+
+   std::cout << header << '\n';
+   for (auto const &f : fields)
+   {
+      if (f.second.empty())
+	 continue;
+      std::cout << f.first << ": ";
+      auto const lines = VectorizeString(f.second, '\n');
+      if (likely(lines.empty() == false))
+      {
+	 std::copy(lines.begin(), std::prev(lines.end()), std::ostream_iterator<std::string>(std::cout, "\n "));
+	 std::cout << *lines.rbegin();
+      }
+      std::cout << '\n';
+   }
+   std::cout << '\n'
+	     << std::flush;
+}
+									/*}}}*/
+// AcqMethod::Fail - A fetch has failed					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcqMethod::Fail(bool Transient)
+{
+
+   Fail("", Transient);
+}
+									/*}}}*/
+// AcqMethod::Fail - A fetch has failed					/*{{{*/
+void pkgAcqMethod::Fail(string Err, bool Transient)
+{
+
+   if (not _error->empty())
+   {
+      while (not _error->empty())
+      {
+	 std::string msg;
+	 if (_error->PopMessage(msg))
+	 {
+	    if (not Err.empty())
+	       Err.append("\n");
+	    Err.append(msg);
+	 }
+      }
+   }
+   if (Err.empty())
+      Err = "Undetermined Error";
+
+   // Strip out junk from the error messages
+   std::transform(Err.begin(), Err.end(), Err.begin(), [](char const c) {
+      if (c == '\r' || c == '\n')
+	 return ' ';
+      return c;
+   });
+   if (IP.empty() == false && _config->FindB("Acquire::Failure::ShowIP", true) == true)
+      Err.append(" ").append(IP);
+
+   std::unordered_map<std::string, std::string> fields;
+   if (Queue != nullptr)
+      try_emplace(fields, "URI", Queue->Uri);
+   else
+      try_emplace(fields, "URI", "<UNKNOWN>");
+   try_emplace(fields, "Message", Err);
+
+   if(FailReason.empty() == false)
+      try_emplace(fields, "FailReason", FailReason);
+   if (UsedMirror.empty() == false)
+      try_emplace(fields, "UsedMirror", UsedMirror);
+   if (Transient == true)
+      try_emplace(fields, "Transient-Failure", "true");
+
+   SendMessage("400 URI Failure", std::move(fields));
+
+   if (Queue != nullptr)
+      Dequeue();
+}
+									/*}}}*/
+// AcqMethod::DropPrivsOrDie - Drop privileges or die		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcqMethod::DropPrivsOrDie()
+{
+   if (!DropPrivileges()) {
+      Fail(false);
+      exit(112);	/* call the european emergency number */
+   }
+}
+
+									/*}}}*/
+// AcqMethod::URIStart - Indicate a download is starting		/*{{{*/
+void pkgAcqMethod::URIStart(FetchResult &Res)
+{
+   if (Queue == 0)
+      abort();
+
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
+   if (Res.Size != 0)
+      try_emplace(fields, "Size", std::to_string(Res.Size));
+   if (Res.LastModified != 0)
+      try_emplace(fields, "Last-Modified", TimeRFC1123(Res.LastModified, true));
+   if (Res.ResumePoint != 0)
+      try_emplace(fields, "Resume-Point", std::to_string(Res.ResumePoint));
+   if (UsedMirror.empty() == false)
+      try_emplace(fields, "UsedMirror", UsedMirror);
+
+   SendMessage("200 URI Start", std::move(fields));
+}
+									/*}}}*/
+// AcqMethod::URIDone - A URI is finished				/*{{{*/
+static void printHashStringList(std::unordered_map<std::string, std::string> &fields, std::string const &Prefix, HashStringList const &list)
+{
+   for (auto const &hash : list)
+   {
+      // very old compatibility name for MD5Sum
+      if (hash.HashType() == "MD5Sum")
+	 try_emplace(fields, Prefix + "MD5-Hash", hash.HashValue());
+      try_emplace(fields, Prefix + hash.HashType() + "-Hash", hash.HashValue());
+   }
+}
+void pkgAcqMethod::URIDone(FetchResult &Res, FetchResult *Alt)
+{
+   if (Queue == 0)
+      abort();
+
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
+   if (Res.Filename.empty() == false)
+      try_emplace(fields, "Filename", Res.Filename);
+   if (Res.Size != 0)
+      try_emplace(fields, "Size", std::to_string(Res.Size));
+   if (Res.LastModified != 0)
+      try_emplace(fields, "Last-Modified", TimeRFC1123(Res.LastModified, true));
+   printHashStringList(fields, "", Res.Hashes);
+
+   if (UsedMirror.empty() == false)
+      try_emplace(fields, "UsedMirror", UsedMirror);
+   if (Res.GPGVOutput.empty() == false)
+   {
+      std::ostringstream os;
+      std::copy(Res.GPGVOutput.begin(), Res.GPGVOutput.end() - 1, std::ostream_iterator<std::string>(os, "\n"));
+      os << *Res.GPGVOutput.rbegin();
+      try_emplace(fields, "GPGVOutput", os.str());
+   }
+   if (Res.ResumePoint != 0)
+      try_emplace(fields, "Resume-Point", std::to_string(Res.ResumePoint));
+   if (Res.IMSHit == true)
+      try_emplace(fields, "IMS-Hit", "true");
+
+   if (Alt != nullptr)
+   {
+      if (Alt->Filename.empty() == false)
+	 try_emplace(fields, "Alt-Filename", Alt->Filename);
+      if (Alt->Size != 0)
+	 try_emplace(fields, "Alt-Size", std::to_string(Alt->Size));
+      if (Alt->LastModified != 0)
+	 try_emplace(fields, "Alt-Last-Modified", TimeRFC1123(Alt->LastModified, true));
+      if (Alt->IMSHit == true)
+	 try_emplace(fields, "Alt-IMS-Hit", "true");
+      printHashStringList(fields, "Alt-", Alt->Hashes);
+   }
+
+   SendMessage("201 URI Done", std::move(fields));
+   Dequeue();
+}
+									/*}}}*/
+// AcqMethod::MediaFail - Synchronous request for new media		/*{{{*/
+// ---------------------------------------------------------------------
+/* This sends a 403 Media Failure message to the APT and waits for it
+   to be ackd */
+bool pkgAcqMethod::MediaFail(string Required,string Drive)
+{
+   fprintf(stdout, "403 Media Failure\nMedia: %s\nDrive: %s\n",
+	    Required.c_str(),Drive.c_str());
+   std::cout << "\n" << std::flush;
+
+   vector<string> MyMessages;
+   
+   /* Here we read messages until we find a 603, each non 603 message is
+      appended to the main message list for later processing */
+   while (1)
+   {
+      if (WaitFd(STDIN_FILENO) == false)
+	 return false;
+      
+      if (ReadMessages(STDIN_FILENO,MyMessages) == false)
+	 return false;
+
+      string Message = MyMessages.front();
+      MyMessages.erase(MyMessages.begin());
+      
+      // Fetch the message number
+      char *End;
+      int Number = strtol(Message.c_str(),&End,10);
+      if (End == Message.c_str())
+      {	 
+	 cerr << "Malformed message!" << endl;
+	 exit(100);
+      }
+
+      // Change ack
+      if (Number == 603)
+      {
+	 while (MyMessages.empty() == false)
+	 {
+	    Messages.push_back(MyMessages.front());
+	    MyMessages.erase(MyMessages.begin());
+	 }
+
+	 return !StringToBool(LookupTag(Message,"Failed"),false);
+      }
+      
+      Messages.push_back(Message);
+   }   
+}
+									/*}}}*/
+// AcqMethod::Configuration - Handle the configuration message		/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses each configuration entry and puts it into the _config 
+   Configuration class. */
+bool pkgAcqMethod::Configuration(string Message)
+{
+   ::Configuration &Cnf = *_config;
+   
+   const char *I = Message.c_str();
+   const char *MsgEnd = I + Message.length();
+   
+   unsigned int Length = strlen("Config-Item");
+   for (; I + Length < MsgEnd; I++)
+   {
+      // Not a config item
+      if (I[Length] != ':' || stringcasecmp(I,I+Length,"Config-Item") != 0)
+	 continue;
+      
+      I += Length + 1;
+      
+      for (; I < MsgEnd && *I == ' '; I++);
+      const char *Equals = (const char*) memchr(I, '=', MsgEnd - I);
+      if (Equals == NULL)
+	 return false;
+      const char *End = (const char*) memchr(Equals, '\n', MsgEnd - Equals);
+      if (End == NULL)
+	 End = MsgEnd;
+      
+      Cnf.Set(DeQuoteString(string(I,Equals-I)),
+	      DeQuoteString(string(Equals+1,End-Equals-1)));
+      I = End;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// AcqMethod::Run - Run the message engine				/*{{{*/
+// ---------------------------------------------------------------------
+/* Fetch any messages and execute them. In single mode it returns 1 if
+   there are no more available messages - any other result is a 
+   fatal failure code! */
+int pkgAcqMethod::Run(bool Single)
+{
+   while (1)
+   {
+      // Block if the message queue is empty
+      if (Messages.empty() == true)
+      {
+	 if (Single == false)
+	    if (WaitFd(STDIN_FILENO) == false)
+	       break;
+	 if (ReadMessages(STDIN_FILENO,Messages) == false)
+	    break;
+      }
+            
+      // Single mode exits if the message queue is empty
+      if (Single == true && Messages.empty() == true)
+	 return -1;
+      
+      string Message = Messages.front();
+      Messages.erase(Messages.begin());
+      
+      // Fetch the message number
+      char *End;
+      int Number = strtol(Message.c_str(),&End,10);
+      if (End == Message.c_str())
+      {	 
+	 cerr << "Malformed message!" << endl;
+	 return 100;
+      }
+
+      switch (Number)
+      {	 
+	 case 601:
+	 if (Configuration(Message) == false)
+	    return 100;
+	 break;
+	 
+	 case 600:
+	 {
+	    FetchItem *Tmp = new FetchItem;
+	    
+	    Tmp->Uri = LookupTag(Message,"URI");
+	    Tmp->Proxy(LookupTag(Message, "Proxy"));
+	    Tmp->DestFile = LookupTag(Message,"FileName");
+	    if (RFC1123StrToTime(LookupTag(Message,"Last-Modified"),Tmp->LastModified) == false)
+	       Tmp->LastModified = 0;
+	    Tmp->IndexFile = StringToBool(LookupTag(Message,"Index-File"),false);
+	    Tmp->FailIgnore = StringToBool(LookupTag(Message,"Fail-Ignore"),false);
+	    Tmp->ExpectedHashes = HashStringList();
+	    for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t)
+	    {
+	       std::string tag = "Expected-";
+	       tag.append(*t);
+	       std::string const hash = LookupTag(Message, tag.c_str());
+	       if (hash.empty() == false)
+		  Tmp->ExpectedHashes.push_back(HashString(*t, hash));
+	    }
+            char *End;
+	    if (Tmp->ExpectedHashes.FileSize() > 0)
+	       Tmp->MaximumSize = Tmp->ExpectedHashes.FileSize();
+	    else
+	       Tmp->MaximumSize = strtoll(LookupTag(Message, "Maximum-Size", "0").c_str(), &End, 10);
+	    Tmp->Next = 0;
+	    
+	    // Append it to the list
+	    FetchItem **I = &Queue;
+	    for (; *I != 0; I = &(*I)->Next);
+	    *I = Tmp;
+	    if (QueueBack == 0)
+	       QueueBack = Tmp;
+
+	    // Notify that this item is to be fetched.
+	    if (URIAcquire(Message, Tmp) == false)
+	       Fail();
+
+	    break;
+	 }
+      }
+   }
+
+   Exit();
+   return 0;
+}
+									/*}}}*/
+// AcqMethod::PrintStatus - privately really send a log/status message	/*{{{*/
+void pkgAcqMethod::PrintStatus(char const * const header, const char* Format,
+			       va_list &args) const
+{
+   string CurrentURI = "<UNKNOWN>";
+   if (Queue != 0)
+      CurrentURI = Queue->Uri;
+   if (UsedMirror.empty() == true)
+      fprintf(stdout, "%s\nURI: %s\nMessage: ",
+	      header, CurrentURI.c_str());
+   else
+      fprintf(stdout, "%s\nURI: %s\nUsedMirror: %s\nMessage: ",
+	      header, CurrentURI.c_str(), UsedMirror.c_str());
+   vfprintf(stdout,Format,args);
+   std::cout << "\n\n" << std::flush;
+}
+									/*}}}*/
+// AcqMethod::Log - Send a log message					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcqMethod::Log(const char *Format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   std::ostringstream outstr;
+   while (true) {
+      bool ret;
+      va_start(args,Format);
+      ret = iovprintf(outstr, Format, args, size);
+      va_end(args);
+      if (ret == true)
+	 break;
+   }
+   std::unordered_map<std::string, std::string> fields;
+   if (Queue != 0)
+      try_emplace(fields, "URI", Queue->Uri);
+   else
+      try_emplace(fields, "URI", "<UNKNOWN>");
+   if (not UsedMirror.empty())
+      try_emplace(fields, "UsedMirror", UsedMirror);
+   try_emplace(fields, "Message", outstr.str());
+   SendMessage("101 Log", std::move(fields));
+}
+									/*}}}*/
+// AcqMethod::Status - Send a status message				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcqMethod::Status(const char *Format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   std::ostringstream outstr;
+   while (true) {
+      bool ret;
+      va_start(args,Format);
+      ret = iovprintf(outstr, Format, args, size);
+      va_end(args);
+      if (ret == true)
+	 break;
+   }
+   std::unordered_map<std::string, std::string> fields;
+   if (Queue != 0)
+      try_emplace(fields, "URI", Queue->Uri);
+   else
+      try_emplace(fields, "URI", "<UNKNOWN>");
+   if (not UsedMirror.empty())
+      try_emplace(fields, "UsedMirror", UsedMirror);
+   try_emplace(fields, "Message", outstr.str());
+   SendMessage("102 Status", std::move(fields));
+}
+									/*}}}*/
+// AcqMethod::Redirect - Send a redirect message                       /*{{{*/
+// ---------------------------------------------------------------------
+/* This method sends the redirect message and dequeues the item as
+ * the worker will enqueue again later on to the right queue */
+void pkgAcqMethod::Redirect(const string &NewURI)
+{
+   if (NewURI.find_first_not_of(" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") != std::string::npos)
+   {
+      _error->Error("SECURITY: URL redirect target contains control characters, rejecting.");
+      Fail();
+      return;
+   }
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
+   try_emplace(fields, "New-URI", NewURI);
+   SendMessage("103 Redirect", std::move(fields));
+   Dequeue();
+}
+                                                                        /*}}}*/
+// AcqMethod::FetchResult::FetchResult - Constructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcqMethod::FetchResult::FetchResult() : LastModified(0),
+                                   IMSHit(false), Size(0), ResumePoint(0), d(NULL)
+{
+}
+									/*}}}*/
+// AcqMethod::FetchResult::TakeHashes - Load hashes			/*{{{*/
+// ---------------------------------------------------------------------
+/* This hides the number of hashes we are supporting from the caller. 
+   It just deals with the hash class. */
+void pkgAcqMethod::FetchResult::TakeHashes(class Hashes &Hash)
+{
+   Hashes = Hash.GetHashStringList();
+}
+									/*}}}*/
+void pkgAcqMethod::Dequeue() {						/*{{{*/
+   FetchItem const * const Tmp = Queue;
+   Queue = Queue->Next;
+   if (Tmp == QueueBack)
+      QueueBack = Queue;
+   delete Tmp;
+}
+									/*}}}*/
+pkgAcqMethod::~pkgAcqMethod() {}
+
+struct pkgAcqMethod::FetchItem::Private
+{
+   std::string Proxy;
+};
+
+pkgAcqMethod::FetchItem::FetchItem() : Next(nullptr), DestFileFd(-1), LastModified(0), IndexFile(false),
+				       FailIgnore(false), MaximumSize(0), d(new Private)
+{}
+
+std::string pkgAcqMethod::FetchItem::Proxy()
+{
+   return d->Proxy;
+}
+
+void pkgAcqMethod::FetchItem::Proxy(std::string const &Proxy)
+{
+   d->Proxy = Proxy;
+}
+
+pkgAcqMethod::FetchItem::~FetchItem() { delete d; }
+
+pkgAcqMethod::FetchResult::~FetchResult() {}
diff --git a/apt-pkg/acquire-method.h b/apt-pkg/acquire-method.h
new file mode 100644
index 0000000..b4b238c
--- /dev/null
+++ b/apt-pkg/acquire-method.h
@@ -0,0 +1,137 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Method - Method helper class + functions
+   
+   These functions are designed to be used within the method task to
+   ease communication with APT.
+   
+   ##################################################################### */
+									/*}}}*/
+
+/** \addtogroup acquire
+ *  @{
+ *
+ *  \file acquire-method.h
+ */
+
+#ifndef PKGLIB_ACQUIRE_METHOD_H
+#define PKGLIB_ACQUIRE_METHOD_H
+
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+
+#include <stdarg.h>
+#include <time.h>
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+
+class APT_PUBLIC pkgAcqMethod
+{
+   protected:
+
+   struct FetchItem
+   {
+      FetchItem *Next;
+
+      std::string Uri;
+      std::string DestFile;
+      int DestFileFd;
+      time_t LastModified;
+      bool IndexFile;
+      bool FailIgnore;
+      HashStringList ExpectedHashes;
+      // a maximum size we will download, this can be the exact filesize
+      // for when we know it or a arbitrary limit when we don't know the
+      // filesize (like a InRelease file)
+      unsigned long long MaximumSize;
+
+      FetchItem();
+      virtual ~FetchItem();
+      std::string Proxy(); // For internal use only.
+      void Proxy(std::string const &Proxy) APT_HIDDEN;
+
+      private:
+      struct Private;
+      Private *const d;
+   };
+
+   struct FetchResult
+   {
+      HashStringList Hashes;
+      std::vector<std::string> GPGVOutput;
+      time_t LastModified;
+      bool IMSHit;
+      std::string Filename;
+      unsigned long long Size;
+      unsigned long long ResumePoint;
+      
+      void TakeHashes(class Hashes &Hash);
+      FetchResult();
+      virtual ~FetchResult();
+      private:
+      void * const d;
+   };
+
+   // State
+   std::vector<std::string> Messages;
+   FetchItem *Queue;
+   FetchItem *QueueBack;
+   std::string FailReason;
+   std::string UsedMirror;
+   std::string IP;
+
+   // Handlers for messages
+   virtual bool Configuration(std::string Message);
+   virtual bool Fetch(FetchItem * /*Item*/) {return true;};
+   virtual bool URIAcquire(std::string const &/*Message*/, FetchItem *Itm) { return Fetch(Itm); };
+
+   // Outgoing messages
+   void Fail(bool Transient = false);
+   inline void Fail(const char *Why, bool Transient = false) {Fail(std::string(Why),Transient);};
+   virtual void Fail(std::string Why, bool Transient = false);
+   virtual void URIStart(FetchResult &Res);
+   virtual void URIDone(FetchResult &Res,FetchResult *Alt = 0);
+   void SendMessage(std::string const &header, std::unordered_map<std::string, std::string> &&fields);
+
+   bool MediaFail(std::string Required,std::string Drive);
+   virtual void Exit() {};
+
+   APT_DEPRECATED_MSG("Use SendMessage instead") void PrintStatus(char const * const header, const char* Format, va_list &args) const;
+
+   public:
+   enum CnfFlags
+   {
+      SingleInstance = (1 << 0),
+      Pipeline = (1 << 1),
+      SendConfig = (1 << 2),
+      LocalOnly = (1 << 3),
+      NeedsCleanup = (1 << 4),
+      Removable = (1 << 5),
+      AuxRequests = (1 << 6),
+      SendURIEncoded = (1 << 7),
+   };
+
+   void Log(const char *Format,...);
+   void Status(const char *Format,...);
+   
+   void Redirect(const std::string &NewURI);
+ 
+   int Run(bool Single = false);
+   inline void SetFailReason(std::string Msg) {FailReason = Msg;};
+   inline void SetIP(std::string aIP) {IP = aIP;};
+   
+   pkgAcqMethod(const char *Ver,unsigned long Flags = 0);
+   virtual ~pkgAcqMethod();
+   void DropPrivsOrDie();
+   private:
+   APT_HIDDEN void Dequeue();
+};
+
+/** @} */
+
+#endif
diff --git a/apt-pkg/acquire-worker.cc b/apt-pkg/acquire-worker.cc
new file mode 100644
index 0000000..1bf07e8
--- /dev/null
+++ b/apt-pkg/acquire-worker.cc
@@ -0,0 +1,1019 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Worker 
+
+   The worker process can startup either as a Configuration prober
+   or as a queue runner. As a configuration prober it only reads the
+   configuration message and 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/acquire-worker.h>
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/proxy.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <sstream>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// Worker::Worker - Constructor for Queue startup			/*{{{*/
+pkgAcquire::Worker::Worker(Queue *Q, MethodConfig *Cnf, pkgAcquireStatus *log) :
+   d(NULL), OwnerQ(Q), Log(log), Config(Cnf), Access(Cnf->Access),
+   CurrentItem(nullptr)
+{
+   Construct();
+}
+									/*}}}*/
+// Worker::Worker - Constructor for method config startup		/*{{{*/
+pkgAcquire::Worker::Worker(MethodConfig *Cnf) : Worker(nullptr, Cnf, nullptr)
+{
+}
+									/*}}}*/
+// Worker::Construct - Constructor helper				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcquire::Worker::Construct()
+{
+   NextQueue = 0;
+   NextAcquire = 0;
+   Process = -1;
+   InFd = -1;
+   OutFd = -1;
+   OutReady = false;
+   InReady = false;
+   Debug = _config->FindB("Debug::pkgAcquire::Worker",false);
+}
+									/*}}}*/
+// Worker::~Worker - Destructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::Worker::~Worker()
+{
+   close(InFd);
+   close(OutFd);
+   
+   if (Process > 0)
+   {
+      /* Closing of stdin is the signal to exit and die when the process
+         indicates it needs cleanup */
+      if (Config->NeedsCleanup == false)
+	 kill(Process,SIGINT);
+      ExecWait(Process,Access.c_str(),true);
+   }   
+}
+									/*}}}*/
+// Worker::Start - Start the worker process				/*{{{*/
+// ---------------------------------------------------------------------
+/* This forks the method and inits the communication channel */
+bool pkgAcquire::Worker::Start()
+{
+   // Get the method path
+   constexpr char const * const methodsDir = "Dir::Bin::Methods";
+   std::string const confItem = std::string(methodsDir) + "::" + Access;
+   std::string Method;
+   if (_config->Exists(confItem))
+	 Method = _config->FindFile(confItem.c_str());
+   else if (Access == "ftp" || Access == "rsh" || Access == "ssh")
+      return _error->Error(_("The method '%s' is unsupported and disabled by default. Consider switching to http(s). Set Dir::Bin::Methods::%s to \"%s\" to enable it again."), Access.c_str(), Access.c_str(), Access.c_str());
+   else
+	 Method = _config->FindDir(methodsDir) + Access;
+   if (FileExists(Method) == false)
+   {
+      if (flNotDir(Method) == "false")
+      {
+	 _error->Error(_("The method '%s' is explicitly disabled via configuration."), Access.c_str());
+	 if (Access == "http" || Access == "https")
+	    _error->Notice(_("If you meant to use Tor remember to use %s instead of %s."), ("tor+" + Access).c_str(), Access.c_str());
+	 return false;
+      }
+      _error->Error(_("The method driver %s could not be found."),Method.c_str());
+      std::string const A(Access.cbegin(), std::find(Access.cbegin(), Access.cend(), '+'));
+      std::string pkg;
+      strprintf(pkg, "apt-transport-%s", A.c_str());
+      _error->Notice(_("Is the package %s installed?"), pkg.c_str());
+      return false;
+   }
+   std::string const Calling = _config->FindDir(methodsDir) + Access;
+
+   if (Debug == true)
+   {
+      std::clog << "Starting method '" << Calling << "'";
+      if (Calling != Method)
+	 std::clog << " ( via " << Method << " )";
+      std::clog << endl;
+   }
+
+   // Create the pipes
+   int Pipes[4] = {-1,-1,-1,-1};
+   if (pipe(Pipes) != 0 || pipe(Pipes+2) != 0)
+   {
+      _error->Errno("pipe","Failed to create IPC pipe to subprocess");
+      for (int I = 0; I != 4; I++)
+	 close(Pipes[I]);
+      return false;
+   }
+   for (int I = 0; I != 4; I++)
+      SetCloseExec(Pipes[I],true);
+
+   // Fork off the process
+   Process = ExecFork();
+   if (Process == 0)
+   {
+      // Setup the FDs
+      dup2(Pipes[1],STDOUT_FILENO);
+      dup2(Pipes[2],STDIN_FILENO);
+      SetCloseExec(STDOUT_FILENO,false);
+      SetCloseExec(STDIN_FILENO,false);
+      SetCloseExec(STDERR_FILENO,false);
+
+      const char * const Args[] = { Calling.c_str(), nullptr };
+      execv(Method.c_str() ,const_cast<char **>(Args));
+      std::cerr << "Failed to exec method " << Calling << " ( via " << Method << ")" << endl;
+      _exit(100);
+   }
+
+   // Fix up our FDs
+   InFd = Pipes[0];
+   OutFd = Pipes[3];
+   SetNonBlock(Pipes[0],true);
+   SetNonBlock(Pipes[3],true);
+   close(Pipes[1]);
+   close(Pipes[2]);
+   OutReady = false;
+   InReady = true;
+
+   // Read the configuration data
+   if (WaitFd(InFd) == false ||
+       ReadMessages() == false)
+      return _error->Error(_("Method %s did not start correctly"),Method.c_str());
+
+   RunMessages();
+   if (OwnerQ != 0)
+      SendConfiguration();
+
+   return true;
+}
+									/*}}}*/
+// Worker::ReadMessages - Read all pending messages into the list	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Worker::ReadMessages()
+{
+   if (::ReadMessages(InFd,MessageQueue) == false)
+      return MethodFailure();
+   return true;
+}
+									/*}}}*/
+// Worker::RunMessage - Empty the message queue				/*{{{*/
+// ---------------------------------------------------------------------
+/* This takes the messages from the message queue and runs them through
+   the parsers in order. */
+enum class APT_HIDDEN MessageType
+{
+   CAPABILITIES = 100,
+   LOG = 101,
+   STATUS = 102,
+   REDIRECT = 103,
+   WARNING = 104,
+   URI_START = 200,
+   URI_DONE = 201,
+   AUX_REQUEST = 351,
+   URI_FAILURE = 400,
+   GENERAL_FAILURE = 401,
+   MEDIA_CHANGE = 403
+};
+static bool isDoomedItem(pkgAcquire::Item const * const Itm)
+{
+   auto const TransItm = dynamic_cast<pkgAcqTransactionItem const * const>(Itm);
+   if (TransItm == nullptr)
+      return false;
+   return TransItm->TransactionManager->State != pkgAcqTransactionItem::TransactionStarted;
+}
+static HashStringList GetHashesFromMessage(std::string const &Prefix, std::string const &Message)
+{
+   HashStringList hsl;
+   for (char const *const *type = HashString::SupportedHashes(); *type != NULL; ++type)
+   {
+      std::string const tagname = Prefix + *type + "-Hash";
+      std::string const hashsum = LookupTag(Message, tagname.c_str());
+      if (hashsum.empty() == false)
+	 hsl.push_back(HashString(*type, hashsum));
+   }
+   return hsl;
+}
+static void APT_NONNULL(3) ChangeSiteIsMirrorChange(std::string const &NewURI, pkgAcquire::ItemDesc &desc, pkgAcquire::Item *const Owner)
+{
+   if (URI::SiteOnly(NewURI) == URI::SiteOnly(desc.URI))
+      return;
+
+   auto const firstSpace = desc.Description.find(" ");
+   if (firstSpace != std::string::npos)
+   {
+      std::string const OldSite = desc.Description.substr(0, firstSpace);
+      if (likely(APT::String::Startswith(desc.URI, OldSite)))
+      {
+	 std::string const OldExtra = desc.URI.substr(OldSite.length() + 1);
+	 if (likely(APT::String::Endswith(NewURI, OldExtra)))
+	 {
+	    std::string const NewSite = NewURI.substr(0, NewURI.length() - OldExtra.length());
+	    Owner->UsedMirror = URI::ArchiveOnly(NewSite);
+	    desc.Description.replace(0, firstSpace, Owner->UsedMirror);
+	 }
+      }
+   }
+}
+bool pkgAcquire::Worker::RunMessages()
+{
+   while (MessageQueue.empty() == false)
+   {
+      string Message = MessageQueue.front();
+      MessageQueue.erase(MessageQueue.begin());
+
+      if (Debug == true)
+	 clog << " <- " << Access << ':' << QuoteString(Message,"\n") << endl;
+
+      // Fetch the message number
+      char *End;
+      MessageType const Number = static_cast<MessageType>(strtoul(Message.c_str(),&End,10));
+      if (End == Message.c_str())
+	 return _error->Error("Invalid message from method %s: %s",Access.c_str(),Message.c_str());
+
+      string URI = LookupTag(Message,"URI");
+      pkgAcquire::Queue::QItem *Itm = NULL;
+      if (URI.empty() == false)
+	 Itm = OwnerQ->FindItem(URI,this);
+
+      if (Itm != NULL)
+      {
+	 // update used mirror
+	 string UsedMirror = LookupTag(Message,"UsedMirror", "");
+	 if (UsedMirror.empty() == false)
+	 {
+	    for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+	       (*O)->UsedMirror = UsedMirror;
+
+	    if (Itm->Description.find(" ") != string::npos)
+	       Itm->Description.replace(0, Itm->Description.find(" "), UsedMirror);
+	 }
+      }
+
+      // Determine the message number and dispatch
+      switch (Number)
+      {
+	 case MessageType::CAPABILITIES:
+	 if (Capabilities(Message) == false)
+	    return _error->Error("Unable to process Capabilities message from %s",Access.c_str());
+	 break;
+
+	 case MessageType::LOG:
+	 if (Debug == true)
+	    clog << " <- (log) " << LookupTag(Message,"Message") << endl;
+	 break;
+
+	 case MessageType::STATUS:
+	 Status = LookupTag(Message,"Message");
+	 break;
+
+	 case MessageType::REDIRECT:
+         {
+            if (Itm == nullptr)
+            {
+               _error->Error("Method gave invalid 103 Redirect message");
+               break;
+            }
+
+	    std::string const GotNewURI = LookupTag(Message,"New-URI",URI.c_str());
+	    if (Config->GetSendURIEncoded())
+	       Itm->URI = GotNewURI;
+	    else
+	    {
+	       ::URI tmpuri{GotNewURI};
+	       tmpuri.Path = pkgAcquire::URIEncode(tmpuri.Path);
+	       Itm->URI = tmpuri;
+	    }
+	    auto NewURI = Itm->URI;
+
+	    auto const AltUris = VectorizeString(LookupTag(Message, "Alternate-URIs"), '\n');
+
+	    ItemDone();
+
+	    // Change the status so that it can be dequeued
+	    for (auto const &O: Itm->Owners)
+	       O->Status = pkgAcquire::Item::StatIdle;
+	    // Mark the item as done (taking care of all queues)
+	    // and then put it in the main queue again
+	    std::vector<Item*> const ItmOwners = Itm->Owners;
+	    OwnerQ->ItemDone(Itm);
+	    Itm = nullptr;
+	    for (auto const &Owner: ItmOwners)
+	    {
+	       pkgAcquire::ItemDesc &desc = Owner->GetItemDesc();
+
+	       // for a simplified retry a method might redirect without URI change
+	       // see also IsRedirectionLoop implementation
+	       bool simpleRetry = false;
+	       if (Config->GetSendURIEncoded())
+	       {
+		  for (auto alt = AltUris.crbegin(); alt != AltUris.crend(); ++alt)
+		     Owner->PushAlternativeURI(std::string(*alt), {}, false);
+		  if (desc.URI == GotNewURI)
+		     simpleRetry = true;
+	       }
+	       else
+	       {
+		  for (auto alt = AltUris.crbegin(); alt != AltUris.crend(); ++alt)
+		  {
+		     ::URI tmpuri{*alt};
+		     tmpuri.Path = pkgAcquire::URIEncode(tmpuri.Path);
+		     Owner->PushAlternativeURI(std::string(tmpuri), {}, false);
+		  }
+		  ::URI tmpuri{desc.URI};
+		  tmpuri.Path = DeQuoteString(tmpuri.Path);
+		  if (GotNewURI == std::string(tmpuri))
+		     simpleRetry = true;
+	       }
+
+	       if (not simpleRetry)
+	       {
+		  if (Owner->IsGoodAlternativeURI(NewURI) == false && Owner->PopAlternativeURI(NewURI) == false)
+		     NewURI.clear();
+		  if (NewURI.empty() || Owner->IsRedirectionLoop(NewURI))
+		  {
+		     std::string msg = Message;
+		     msg.append("\nFailReason: RedirectionLoop");
+		     Owner->Failed(msg, Config);
+		     if (Log != nullptr)
+			Log->Fail(Owner->GetItemDesc());
+		     continue;
+		  }
+
+		  if (Log != nullptr)
+		     Log->Done(desc);
+
+		  ChangeSiteIsMirrorChange(NewURI, desc, Owner);
+		  desc.URI = NewURI;
+	       }
+	       if (isDoomedItem(Owner) == false)
+		  OwnerQ->Owner->Enqueue(desc);
+	    }
+            break;
+         }
+
+	 case MessageType::WARNING:
+	    _error->Warning("%s: %s", Itm ? Itm->Owner ? Itm->Owner->DescURI().c_str() : Access.c_str() : Access.c_str(), LookupTag(Message, "Message").c_str());
+	    break;
+
+	 case MessageType::URI_START:
+	 {
+	    if (Itm == nullptr)
+	    {
+	       _error->Error("Method gave invalid 200 URI Start message");
+	       break;
+	    }
+
+	    CurrentItem = Itm;
+	    Itm->CurrentSize = 0;
+	    Itm->TotalSize = strtoull(LookupTag(Message,"Size","0").c_str(), NULL, 10);
+	    Itm->ResumePoint = strtoull(LookupTag(Message,"Resume-Point","0").c_str(), NULL, 10);
+	    for (auto const Owner: Itm->Owners)
+	    {
+	       Owner->Start(Message, Itm->TotalSize);
+	       // Display update before completion
+	       if (Log != nullptr)
+	       {
+		  if (Log->MorePulses == true)
+		     Log->Pulse(Owner->GetOwner());
+		  Log->Fetch(Owner->GetItemDesc());
+	       }
+	    }
+
+	    break;
+	 }
+
+	 case MessageType::URI_DONE:
+	 {
+	    if (Itm == nullptr)
+	    {
+	       _error->Error("Method gave invalid 201 URI Done message");
+	       break;
+	    }
+
+	    PrepareFiles("201::URIDone", Itm);
+
+	    // Display update before completion
+	    if (Log != 0 && Log->MorePulses == true)
+	       for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+		  Log->Pulse((*O)->GetOwner());
+
+	    HashStringList ReceivedHashes;
+	    {
+	       std::string const givenfilename = LookupTag(Message, "Filename");
+	       std::string const filename = givenfilename.empty() ? Itm->Owner->DestFile : givenfilename;
+	       // see if we got hashes to verify
+	       ReceivedHashes = GetHashesFromMessage("", Message);
+	       // not all methods always sent Hashes our way
+	       if (ReceivedHashes.usable() == false)
+	       {
+		  HashStringList const ExpectedHashes = Itm->GetExpectedHashes();
+		  if (ExpectedHashes.usable() == true && RealFileExists(filename))
+		  {
+		     Hashes calc(ExpectedHashes);
+		     FileFd file(filename, FileFd::ReadOnly, FileFd::None);
+		     calc.AddFD(file);
+		     ReceivedHashes = calc.GetHashStringList();
+		  }
+	       }
+
+	       // only local files can refer other filenames and counting them as fetched would be unfair
+	       if (Log != NULL && Itm->Owner->Complete == false && Itm->Owner->Local == false && givenfilename == filename)
+		  Log->Fetched(ReceivedHashes.FileSize(),atoi(LookupTag(Message,"Resume-Point","0").c_str()));
+	    }
+
+	    std::vector<Item*> const ItmOwners = Itm->Owners;
+	    OwnerQ->ItemDone(Itm);
+	    Itm = NULL;
+
+	    bool const isIMSHit = StringToBool(LookupTag(Message,"IMS-Hit"),false) ||
+	       StringToBool(LookupTag(Message,"Alt-IMS-Hit"),false);
+	    auto const forcedHash = _config->Find("Acquire::ForceHash");
+	    for (auto const Owner: ItmOwners)
+	    {
+	       HashStringList const ExpectedHashes = Owner->GetExpectedHashes();
+	       if(_config->FindB("Debug::pkgAcquire::Auth", false) == true)
+	       {
+		  std::clog << "201 URI Done: " << Owner->DescURI() << endl
+		     << "ReceivedHash:" << endl;
+		  for (HashStringList::const_iterator hs = ReceivedHashes.begin(); hs != ReceivedHashes.end(); ++hs)
+		     std::clog <<  "\t- " << hs->toStr() << std::endl;
+		  std::clog << "ExpectedHash:" << endl;
+		  for (HashStringList::const_iterator hs = ExpectedHashes.begin(); hs != ExpectedHashes.end(); ++hs)
+		     std::clog <<  "\t- " << hs->toStr() << std::endl;
+		  std::clog << endl;
+	       }
+
+	       // decide if what we got is what we expected
+	       bool consideredOkay = false;
+	       if ((forcedHash.empty() && ExpectedHashes.empty() == false) ||
+		     (forcedHash.empty() == false && ExpectedHashes.usable()))
+	       {
+		  if (ReceivedHashes.empty())
+		  {
+		     /* IMS-Hits can't be checked here as we will have uncompressed file,
+			but the hashes for the compressed file. What we have was good through
+			so all we have to ensure later is that we are not stalled. */
+		     consideredOkay = isIMSHit;
+		  }
+		  else if (ReceivedHashes == ExpectedHashes)
+		     consideredOkay = true;
+		  else
+		     consideredOkay = false;
+
+	       }
+	       else
+		  consideredOkay = !Owner->HashesRequired();
+
+	       if (consideredOkay == true)
+		  consideredOkay = Owner->VerifyDone(Message, Config);
+	       else // hashsum mismatch
+		  Owner->Status = pkgAcquire::Item::StatAuthError;
+
+
+	       if (consideredOkay == true)
+	       {
+		  if (isDoomedItem(Owner) == false)
+		     Owner->Done(Message, ReceivedHashes, Config);
+		  if (Log != nullptr)
+		  {
+		     if (isIMSHit)
+			Log->IMSHit(Owner->GetItemDesc());
+		     else
+			Log->Done(Owner->GetItemDesc());
+		  }
+	       }
+	       else
+	       {
+		  auto SavedDesc = Owner->GetItemDesc();
+		  if (isDoomedItem(Owner) == false)
+		  {
+		     if (Message.find("\nFailReason:") == std::string::npos)
+		     {
+			if (ReceivedHashes != ExpectedHashes)
+			   Message.append("\nFailReason: HashSumMismatch");
+			else
+			   Message.append("\nFailReason: WeakHashSums");
+		     }
+		     Owner->Failed(Message,Config);
+		  }
+		  if (Log != nullptr)
+		     Log->Fail(SavedDesc);
+	       }
+	    }
+	    ItemDone();
+	    break;
+	 }
+
+	 case MessageType::AUX_REQUEST:
+	 {
+	    if (Itm == nullptr)
+	    {
+	       _error->Error("Method gave invalid Aux Request message");
+	       break;
+	    }
+	    else if (Config->GetAuxRequests() == false)
+	    {
+	       std::vector<Item *> const ItmOwners = Itm->Owners;
+	       Message.append("\nMessage: Method tried to make an Aux Request while not being allowed to do them");
+	       OwnerQ->ItemDone(Itm);
+	       Itm = nullptr;
+	       HandleFailure(ItmOwners, Config, Log, Message, false, false);
+	       ItemDone();
+
+	       std::string Msg = "600 URI Acquire\n";
+	       Msg.reserve(200);
+	       Msg += "URI: " + LookupTag(Message, "Aux-URI", "");
+	       Msg += "\nFilename: /nonexistent/auxrequest.blocked";
+	       Msg += "\n\n";
+	       if (Debug == true)
+		  clog << " -> " << Access << ':' << QuoteString(Msg, "\n") << endl;
+	       OutQueue += Msg;
+	       OutReady = true;
+	       break;
+	    }
+
+	    auto maxsizestr = LookupTag(Message, "MaximumSize", "");
+	    unsigned long long const MaxSize = maxsizestr.empty() ? 0 : strtoull(maxsizestr.c_str(), nullptr, 10);
+	    new pkgAcqAuxFile(Itm->Owner, this, LookupTag(Message, "Aux-ShortDesc", ""),
+			      LookupTag(Message, "Aux-Description", ""), LookupTag(Message, "Aux-URI", ""),
+			      GetHashesFromMessage("Aux-", Message), MaxSize);
+	    break;
+	 }
+
+	 case MessageType::URI_FAILURE:
+	 {
+	    if (Itm == nullptr)
+	    {
+	       std::string const msg = LookupTag(Message,"Message");
+	       _error->Error("Method gave invalid 400 URI Failure message: %s", msg.c_str());
+	       break;
+	    }
+
+	    PrepareFiles("400::URIFailure", Itm);
+
+	    // Display update before completion
+	    if (Log != nullptr && Log->MorePulses == true)
+	       for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+		  Log->Pulse((*O)->GetOwner());
+
+	    std::vector<Item*> const ItmOwners = Itm->Owners;
+	    OwnerQ->ItemDone(Itm);
+	    Itm = nullptr;
+
+	    bool errTransient = false, errAuthErr = false;
+	    if (StringToBool(LookupTag(Message, "Transient-Failure"), false) == true)
+	       errTransient = true;
+	    else
+	    {
+	       std::string const failReason = LookupTag(Message, "FailReason");
+	       {
+		  auto const reasons = { "Timeout", "ConnectionRefused",
+		     "ConnectionTimedOut", "ResolveFailure", "TmpResolveFailure" };
+		  errTransient = std::find(std::begin(reasons), std::end(reasons), failReason) != std::end(reasons);
+	       }
+	       if (errTransient == false)
+	       {
+		  auto const reasons = { "HashSumMismatch", "WeakHashSums", "MaximumSizeExceeded" };
+		  errAuthErr = std::find(std::begin(reasons), std::end(reasons), failReason) != std::end(reasons);
+	       }
+	    }
+	    HandleFailure(ItmOwners, Config, Log, Message, errTransient, errAuthErr);
+	    ItemDone();
+
+	    break;
+	 }
+
+	 case MessageType::GENERAL_FAILURE:
+	 _error->Error("Method %s General failure: %s",Access.c_str(),LookupTag(Message,"Message").c_str());
+	 break;
+
+	 case MessageType::MEDIA_CHANGE:
+	 MediaChange(Message);
+	 break;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+void pkgAcquire::Worker::HandleFailure(std::vector<pkgAcquire::Item *> const &ItmOwners, /*{{{*/
+				       pkgAcquire::MethodConfig *const Config, pkgAcquireStatus *const Log,
+				       std::string const &Message, bool const errTransient, bool const errAuthErr)
+{
+   auto currentTime = clock::now();
+   for (auto const Owner : ItmOwners)
+   {
+      std::string NewURI;
+      if (errTransient == true && Config->LocalOnly == false && Owner->Retries != 0)
+      {
+	 --Owner->Retries;
+	 Owner->FailMessage(Message);
+	 auto SavedDesc = Owner->GetItemDesc();
+	 if (_config->FindB("Acquire::Retries::Delay", true))
+	 {
+	    auto Iter = _config->FindI("Acquire::Retries", 3) - Owner->Retries - 1;
+	    auto const MaxDur = _config->FindI("Acquire::Retries::Delay::Maximum", 30);
+	    auto Dur =  std::chrono::seconds(std::min(1 << Iter, MaxDur));
+	    if (_config->FindB("Debug::Acquire::Retries"))
+	       std::clog << "Delaying " << SavedDesc.Description << " by " << Dur.count() << " seconds" << std::endl;
+	    Owner->FetchAfter(currentTime + Dur);
+	 }
+	 else
+	 {
+	    Owner->FetchAfter(currentTime);
+	 }
+
+	 if (Log != nullptr)
+	    Log->Fail(SavedDesc);
+	 if (isDoomedItem(Owner) == false)
+	    OwnerQ->Owner->Enqueue(SavedDesc);
+      }
+      else
+      {
+	 if (errAuthErr)
+	    Owner->RemoveAlternativeSite(URI::SiteOnly(Owner->GetItemDesc().URI));
+	 if (Owner->PopAlternativeURI(NewURI))
+	 {
+	    Owner->FailMessage(Message);
+	    auto &desc = Owner->GetItemDesc();
+	    if (Log != nullptr)
+	       Log->Fail(desc);
+	    ChangeSiteIsMirrorChange(NewURI, desc, Owner);
+	    desc.URI = NewURI;
+	    if (isDoomedItem(Owner) == false)
+	       OwnerQ->Owner->Enqueue(desc);
+	 }
+	 else
+	 {
+	    if (errAuthErr && Owner->GetExpectedHashes().empty() == false)
+	       Owner->Status = pkgAcquire::Item::StatAuthError;
+	    else if (errTransient)
+	       Owner->Status = pkgAcquire::Item::StatTransientNetworkError;
+	    auto SavedDesc = Owner->GetItemDesc();
+	    if (isDoomedItem(Owner) == false)
+	       Owner->Failed(Message, Config);
+	    if (Log != nullptr)
+	       Log->Fail(SavedDesc);
+	 }
+      }
+   }
+}
+									/*}}}*/
+// Worker::Capabilities - 100 Capabilities handler			/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses the capabilities message and dumps it into the configuration
+   structure. */
+bool pkgAcquire::Worker::Capabilities(string Message)
+{
+   if (Config == 0)
+      return true;
+
+   Config->Version = LookupTag(Message,"Version");
+   Config->SingleInstance = StringToBool(LookupTag(Message,"Single-Instance"),false);
+   Config->Pipeline = StringToBool(LookupTag(Message,"Pipeline"),false);
+   Config->SendConfig = StringToBool(LookupTag(Message,"Send-Config"),false);
+   Config->LocalOnly = StringToBool(LookupTag(Message,"Local-Only"),false);
+   Config->NeedsCleanup = StringToBool(LookupTag(Message,"Needs-Cleanup"),false);
+   Config->Removable = StringToBool(LookupTag(Message,"Removable"),false);
+   Config->SetAuxRequests(StringToBool(LookupTag(Message, "AuxRequests"), false));
+   if (_config->FindB("Acquire::Send-URI-Encoded", true))
+      Config->SetSendURIEncoded(StringToBool(LookupTag(Message, "Send-URI-Encoded"), false));
+
+   // Some debug text
+   if (Debug == true)
+   {
+      clog << "Configured access method " << Config->Access << endl;
+      clog << "Version:" << Config->Version << " SingleInstance:" << Config->SingleInstance
+	   << " Pipeline:" << Config->Pipeline << " SendConfig:" << Config->SendConfig
+	   << " LocalOnly: " << Config->LocalOnly << " NeedsCleanup: " << Config->NeedsCleanup
+	   << " Removable: " << Config->Removable << " AuxRequests: " << Config->GetAuxRequests()
+	   << " SendURIEncoded: " << Config->GetSendURIEncoded() << '\n';
+   }
+
+   return true;
+}
+									/*}}}*/
+// Worker::MediaChange - Request a media change				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Worker::MediaChange(string Message)
+{
+   int status_fd = _config->FindI("APT::Status-Fd",-1);
+   if(status_fd > 0)
+   {
+      string Media = LookupTag(Message,"Media");
+      string Drive = LookupTag(Message,"Drive");
+      ostringstream msg,status;
+      ioprintf(msg,_("Please insert the disc labeled: "
+		     "'%s' "
+		     "in the drive '%s' and press [Enter]."),
+	       Media.c_str(),Drive.c_str());
+      status << "media-change: "  // message
+	     << Media  << ":"     // media
+	     << Drive  << ":"     // drive
+	     << msg.str()         // l10n message
+	     << endl;
+
+      std::string const dlstatus = status.str();
+      FileFd::Write(status_fd, dlstatus.c_str(), dlstatus.size());
+   }
+
+   if (Log == 0 || Log->MediaChange(LookupTag(Message,"Media"),
+				    LookupTag(Message,"Drive")) == false)
+   {
+      char S[300];
+      snprintf(S,sizeof(S),"603 Media Changed\nFailed: true\n\n");
+      if (Debug == true)
+	 clog << " -> " << Access << ':' << QuoteString(S,"\n") << endl;
+      OutQueue += S;
+      OutReady = true;
+      return true;
+   }
+
+   char S[300];
+   snprintf(S,sizeof(S),"603 Media Changed\n\n");
+   if (Debug == true)
+      clog << " -> " << Access << ':' << QuoteString(S,"\n") << endl;
+   OutQueue += S;
+   OutReady = true;
+   return true;
+}
+									/*}}}*/
+// Worker::SendConfiguration - Send the config to the method		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Worker::SendConfiguration()
+{
+   if (Config->SendConfig == false)
+      return true;
+
+   if (OutFd == -1)
+      return false;
+
+   /* Write out all of the configuration directives by walking the
+      configuration tree */
+   std::ostringstream Message;
+   Message << "601 Configuration\n";
+   if (not _config->Exists("Acquire::Send-URI-Encoded"))
+      Message << "Config-Item: Acquire::Send-URI-Encoded=1\n";
+   _config->Dump(Message, NULL, "Config-Item: %F=%V\n", false);
+   Message << '\n';
+
+   if (Debug == true)
+      clog << " -> " << Access << ':' << QuoteString(Message.str(),"\n") << endl;
+   OutQueue += Message.str();
+   OutReady = true;
+
+   return true;
+}
+									/*}}}*/
+// Worker::QueueItem - Add an item to the outbound queue		/*{{{*/
+// ---------------------------------------------------------------------
+/* Send a URI Acquire message to the method */
+bool pkgAcquire::Worker::QueueItem(pkgAcquire::Queue::QItem *Item)
+{
+   if (OutFd == -1)
+      return false;
+
+   if (isDoomedItem(Item->Owner))
+      return true;
+
+   Item->SyncDestinationFiles();
+
+   string Message = "600 URI Acquire\n";
+   Message.reserve(300);
+   URI URL(Item->URI);
+   if (Config->GetSendURIEncoded())
+      Message += "URI: " + Item->URI;
+   else
+   {
+      URL.Path = DeQuoteString(URL.Path);
+      Message += "URI: " + std::string(URL);
+   }
+   Message += "\nFilename: " + Item->Owner->DestFile;
+
+   // FIXME: We should not hard code proxy protocols here.
+   if (URL.Access == "http" || URL.Access == "https")
+   {
+      AutoDetectProxy(URL);
+      if (_config->Exists("Acquire::" + URL.Access + "::proxy::" + URL.Host))
+      {
+	 Message += "\nProxy: " + _config->Find("Acquire::" + URL.Access + "::proxy::" + URL.Host);
+      }
+   }
+
+   HashStringList const hsl = Item->GetExpectedHashes();
+   for (HashStringList::const_iterator hs = hsl.begin(); hs != hsl.end(); ++hs)
+      Message += "\nExpected-" + hs->HashType() + ": " + hs->HashValue();
+
+   Message += Item->Custom600Headers();
+
+   if (hsl.FileSize() == 0 && Message.find("\nMaximum-Size: ") == std::string::npos)
+   {
+      unsigned long long FileSize = Item->GetMaximumSize();
+      if(FileSize > 0)
+      {
+	 string MaximumSize;
+	 strprintf(MaximumSize, "%llu", FileSize);
+	 Message += "\nMaximum-Size: " + MaximumSize;
+      }
+   }
+
+   Message += "\n\n";
+
+   if (RealFileExists(Item->Owner->DestFile))
+   {
+      std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+      ChangeOwnerAndPermissionOfFile("Item::QueueURI", Item->Owner->DestFile.c_str(),
+                                     SandboxUser.c_str(), ROOT_GROUP, 0600);
+   }
+
+   if (Debug == true)
+      clog << " -> " << Access << ':' << QuoteString(Message,"\n") << endl;
+   OutQueue += Message;
+   OutReady = true;
+
+   return true;
+}
+									/*}}}*/
+// Worker::ReplyAux - reply to an aux request from this worker		/*{{{*/
+bool pkgAcquire::Worker::ReplyAux(pkgAcquire::ItemDesc const &Item)
+{
+   if (OutFd == -1)
+      return false;
+
+   if (isDoomedItem(Item.Owner))
+      return true;
+
+   string Message = "600 URI Acquire\n";
+   Message.reserve(200);
+   Message += "URI: " + Item.URI;
+   if (RealFileExists(Item.Owner->DestFile))
+   {
+      if (Item.Owner->Status == pkgAcquire::Item::StatDone)
+      {
+	 std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+	 ChangeOwnerAndPermissionOfFile("Worker::ReplyAux", Item.Owner->DestFile.c_str(),
+					SandboxUser.c_str(), ROOT_GROUP, 0600);
+	 Message += "\nFilename: " + Item.Owner->DestFile;
+      }
+      else
+      {
+	 // we end up here in case we would need root-rights to delete a file,
+	 // but we run the command as non-root… (yes, it is unlikely)
+	 Message += "\nFilename: " + flCombine("/nonexistent", Item.Owner->DestFile);
+      }
+   }
+   else
+      Message += "\nFilename: " + Item.Owner->DestFile;
+   Message += "\n\n";
+
+   if (Debug == true)
+      clog << " -> " << Access << ':' << QuoteString(Message, "\n") << endl;
+   OutQueue += Message;
+   OutReady = true;
+
+   return true;
+}
+									/*}}}*/
+// Worker::OutFdRead - Out bound FD is ready				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Worker::OutFdReady()
+{
+   int Res;
+   do
+   {
+      Res = write(OutFd,OutQueue.c_str(),OutQueue.length());
+   }
+   while (Res < 0 && errno == EINTR);
+
+   if (Res <= 0)
+      return MethodFailure();
+
+   OutQueue.erase(0,Res);
+   if (OutQueue.empty() == true)
+      OutReady = false;
+
+   return true;
+}
+									/*}}}*/
+// Worker::InFdRead - In bound FD is ready				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Worker::InFdReady()
+{
+   if (ReadMessages() == false)
+      return false;
+   RunMessages();
+   return true;
+}
+									/*}}}*/
+// Worker::MethodFailure - Called when the method fails			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called when the method is believed to have failed, probably because
+   read returned -1. */
+bool pkgAcquire::Worker::MethodFailure()
+{
+   _error->Error("Method %s has died unexpectedly!",Access.c_str());
+
+   // do not reap the child here to show meaningful error to the user
+   ExecWait(Process,Access.c_str(),false);
+   Process = -1;
+   close(InFd);
+   close(OutFd);
+   InFd = -1;
+   OutFd = -1;
+   OutReady = false;
+   InReady = false;
+   OutQueue = string();
+   MessageQueue.erase(MessageQueue.begin(),MessageQueue.end());
+
+   return false;
+}
+									/*}}}*/
+// Worker::Pulse - Called periodically					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcquire::Worker::Pulse()
+{
+   if (CurrentItem == 0)
+      return;
+
+   struct stat Buf;
+   if (stat(CurrentItem->Owner->DestFile.c_str(),&Buf) != 0)
+      return;
+   CurrentItem->CurrentSize = Buf.st_size;
+}
+									/*}}}*/
+// Worker::ItemDone - Called when the current item is finished		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcquire::Worker::ItemDone()
+{
+   CurrentItem = nullptr;
+   Status = string();
+}
+									/*}}}*/
+void pkgAcquire::Worker::PrepareFiles(char const * const caller, pkgAcquire::Queue::QItem const * const Itm)/*{{{*/
+{
+   if (RealFileExists(Itm->Owner->DestFile))
+   {
+      ChangeOwnerAndPermissionOfFile(caller, Itm->Owner->DestFile.c_str(), "root", ROOT_GROUP, 0644);
+      std::string const filename = Itm->Owner->DestFile;
+      for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+      {
+	 pkgAcquire::Item const * const Owner = *O;
+	 if (Owner->DestFile == filename || filename == "/dev/null")
+	    continue;
+	 RemoveFile("PrepareFiles", Owner->DestFile);
+	 if (link(filename.c_str(), Owner->DestFile.c_str()) != 0)
+	 {
+	    // different mounts can't happen for us as we download to lists/ by default,
+	    // but if the system is reused by others the locations can potentially be on
+	    // different disks, so use symlink as poor-men replacement.
+	    // FIXME: Real copying as last fallback, but that is costly, so offload to a method preferable
+	    if (symlink(filename.c_str(), Owner->DestFile.c_str()) != 0)
+	       _error->Error("Can't create (sym)link of file %s to %s", filename.c_str(), Owner->DestFile.c_str());
+	 }
+      }
+   }
+   else
+   {
+      for (pkgAcquire::Queue::QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+	 RemoveFile("PrepareFiles", (*O)->DestFile);
+   }
+}
+									/*}}}*/
diff --git a/apt-pkg/acquire-worker.h b/apt-pkg/acquire-worker.h
new file mode 100644
index 0000000..f59d659
--- /dev/null
+++ b/apt-pkg/acquire-worker.h
@@ -0,0 +1,324 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire Worker - Worker process manager
+
+   Each worker class is associated with exactly one subprocess.
+
+   ##################################################################### */
+									/*}}}*/
+
+/** \addtogroup acquire
+ *  @{
+ *
+ *  \file acquire-worker.h
+ */
+
+#ifndef PKGLIB_ACQUIRE_WORKER_H
+#define PKGLIB_ACQUIRE_WORKER_H
+
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/weakptr.h>
+
+#include <string>
+#include <vector>
+#include <sys/types.h>
+
+/** \brief A fetch subprocess.
+ *
+ *  A worker process is responsible for one stage of the fetch.  This
+ *  class encapsulates the communications protocol between the master
+ *  process and the worker, from the master end.
+ *
+ *  Each worker is intrinsically placed on two linked lists.  The
+ *  Queue list (maintained in the #NextQueue variable) is maintained
+ *  by the pkgAcquire::Queue class; it represents the set of workers
+ *  assigned to a particular queue.  The Acquire list (maintained in
+ *  the #NextAcquire variable) is maintained by the pkgAcquire class;
+ *  it represents the set of active workers for a particular
+ *  pkgAcquire object.
+ *
+ *  \todo Like everything else in the Acquire system, this has way too
+ *  many protected items.
+ *
+ *  \sa pkgAcqMethod, pkgAcquire::Item, pkgAcquire
+ */
+class APT_PUBLIC pkgAcquire::Worker : public WeakPointable
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+  
+   friend class pkgAcquire;
+   
+   protected:
+   friend class Queue;
+
+   /** \brief The next link on the Queue list.
+    *
+    *  \todo This is always NULL; is it just for future use?
+    */
+   Worker *NextQueue;
+
+   /** \brief The next link on the Acquire list. */
+   Worker *NextAcquire;
+   
+   /** \brief The Queue with which this worker is associated. */
+   Queue *OwnerQ;
+
+   /** \brief The download progress indicator to which progress
+    *  messages should be sent.
+    */
+   pkgAcquireStatus *Log;
+
+   /** \brief The configuration of this method.  On startup, the
+    *  target of this pointer is filled in with basic data about the
+    *  method, as reported by the worker.
+    */
+   MethodConfig *Config;
+
+   /** \brief The access method to be used by this worker.
+    *
+    *  \todo Doesn't this duplicate Config->Access?
+    */
+   std::string Access;
+
+   /** \brief The PID of the subprocess. */
+   pid_t Process;
+
+   /** \brief A file descriptor connected to the standard output of
+    *  the subprocess.
+    *
+    *  Used to read messages and data from the subprocess.
+    */
+   int InFd;
+
+   /** \brief A file descriptor connected to the standard input of the
+    *  subprocess.
+    *
+    *  Used to send commands and configuration data to the subprocess.
+    */
+   int OutFd;
+
+   /** \brief The socket to send SCM_RIGHTS message through
+    */
+   int PrivSepSocketFd;
+   int PrivSepSocketFdChild;
+
+   /** \brief Set to \b true if the worker is in a state in which it
+    *  might generate data or command responses.
+    *
+    *  \todo Is this right?  It's a guess.
+    */
+   bool InReady;
+
+   /** \brief Set to \b true if the worker is in a state in which it
+    *  is legal to send commands to it.
+    *
+    *  \todo Is this right?
+    */
+   bool OutReady;
+   
+   /** If \b true, debugging output will be sent to std::clog. */
+   bool Debug;
+
+   /** \brief The raw text values of messages received from the
+    *  worker, in sequence.
+    */
+   std::vector<std::string> MessageQueue;
+
+   /** \brief Buffers pending writes to the subprocess.
+    *
+    *  \todo Wouldn't a std::dequeue be more appropriate?
+    */
+   std::string OutQueue;
+   
+   /** \brief Common code for the constructor.
+    *
+    *  Initializes NextQueue and NextAcquire to NULL; Process, InFd,
+    *  and OutFd to -1, OutReady and InReady to \b false, and Debug
+    *  from _config.
+    */
+   void Construct();
+   
+   /** \brief Retrieve any available messages from the subprocess.
+    *
+    *  The messages are retrieved as in \link strutl.h ReadMessages()\endlink, and
+    *  #MethodFailure() is invoked if an error occurs; in particular,
+    *  if the pipe to the subprocess dies unexpectedly while a message
+    *  is being read.
+    *
+    *  \return \b true if the messages were successfully read, \b
+    *  false otherwise.
+    */
+   bool ReadMessages();
+
+   /** \brief Parse and dispatch pending messages.
+    *
+    *  This dispatches the message in a manner appropriate for its
+    *  type.
+    *
+    *  \todo Several message types lack separate handlers.
+    *
+    *  \sa Capabilities(), SendConfiguration(), MediaChange()
+    */
+   bool RunMessages();
+
+   /** \brief Read and dispatch any pending messages from the
+    *  subprocess.
+    *
+    *  \return \b false if the subprocess died unexpectedly while a
+    *  message was being transmitted.
+    */
+   bool InFdReady();
+
+   /** \brief Send any pending commands to the subprocess.
+    *
+    *  This method will fail if there is no pending output.
+    *
+    *  \return \b true if all commands were succeeded, \b false if an
+    *  error occurred (in which case MethodFailure() will be invoked).
+    */
+   bool OutFdReady();
+   
+   /** \brief Handle a 100 Capabilities response from the subprocess.
+    *
+    *  \param Message the raw text of the message from the subprocess.
+    *
+    *  The message will be parsed and its contents used to fill
+    *  #Config.  If #Config is NULL, this routine is a NOP.
+    *
+    *  \return \b true.
+    */
+   bool Capabilities(std::string Message);
+
+   /** \brief Send a 601 Configuration message (containing the APT
+    *  configuration) to the subprocess.
+    *
+    *  The APT configuration will be send to the subprocess in a
+    *  message of the following form:
+    *
+    *  <pre>
+    *  601 Configuration
+    *  Config-Item: Fully-Qualified-Item=Val
+    *  Config-Item: Fully-Qualified-Item=Val
+    *  ...
+    *  </pre>
+    *
+    *  \return \b true if the command was successfully sent, \b false
+    *  otherwise.
+    */
+   bool SendConfiguration();
+
+   /** \brief Handle a 403 Media Change message.
+    *
+    *  \param Message the raw text of the message; the Media field
+    *  indicates what type of media should be changed, and the Drive
+    *  field indicates where the media is located.
+    *
+    *  Invokes pkgAcquireStatus::MediaChange(Media, Drive) to ask the
+    *  user to swap disks; informs the subprocess of the result (via
+    *  603 Media Changed, with the Failed field set to \b true if the
+    *  user cancelled the media change).
+    */
+   bool MediaChange(std::string Message);
+   
+   /** \brief Invoked when the worked process dies unexpectedly.
+    *
+    *  Waits for the subprocess to terminate and generates an error if
+    *  it terminated abnormally, then closes and blanks out all file
+    *  descriptors.  Discards all pending messages from the
+    *  subprocess.
+    *
+    *  \return \b false.
+    */
+   bool MethodFailure();
+
+   /** \brief Invoked when a fetch job is completed, either
+    *  successfully or unsuccessfully.
+    *
+    *  Resets the status information for the worker process.
+    */
+   void ItemDone();
+   
+   public:
+   
+   /** \brief The queue entry that is currently being downloaded. */
+   pkgAcquire::Queue::QItem *CurrentItem;
+
+   /** \brief The most recent status string received from the
+    *  subprocess.
+    */
+   std::string Status;
+
+   /** \brief Tell the subprocess to download the given item.
+    *
+    *  \param Item the item to queue up.
+    *  \return \b true if the item was successfully enqueued.
+    *
+    *  Queues up a 600 URI Acquire message for the given item to be
+    *  sent at the next possible moment.  Does \e not flush the output
+    *  queue.
+    */
+   bool QueueItem(pkgAcquire::Queue::QItem *Item);
+   APT_HIDDEN bool ReplyAux(pkgAcquire::ItemDesc const &Item);
+
+   /** \brief Start up the worker and fill in #Config.
+    *
+    *  Reads the first message from the worker, which is assumed to be
+    *  a 100 Capabilities message.
+    *
+    *  \return \b true if all operations completed successfully.
+    */
+   bool Start();
+
+   /** \brief Update the worker statistics (CurrentSize, TotalSize,
+    *  etc).
+    */
+   void Pulse();
+
+   /** \return The fetch method configuration. */
+   inline const MethodConfig *GetConf() const {return Config;};
+
+   /** \brief Create a new Worker to download files.
+    *
+    *  \param OwnerQ The queue into which this worker should be
+    *  placed.
+    *
+    *  \param Config A location in which to store information about
+    *  the fetch method.
+    *
+    *  \param Log The download progress indicator that should be used
+    *  to report the progress of this worker.
+    */
+   Worker(Queue *OwnerQ,MethodConfig *Config,pkgAcquireStatus *Log);
+
+   /** \brief Create a new Worker that should just retrieve
+    *  information about the fetch method.
+    *
+    *  Nothing in particular forces you to refrain from actually
+    *  downloading stuff, but the various status callbacks won't be
+    *  invoked.
+    *
+    *  \param Config A location in which to store information about
+    *  the fetch method.
+    */
+   explicit Worker(MethodConfig *Config);
+
+   /** \brief Clean up this worker.
+    *
+    *  Closes the file descriptors; if MethodConfig::NeedsCleanup is
+    *  \b false, also rudely interrupts the worker with a SIGINT.
+    */
+   virtual ~Worker();
+
+private:
+   APT_HIDDEN void PrepareFiles(char const * const caller, pkgAcquire::Queue::QItem const * const Itm);
+   APT_HIDDEN void HandleFailure(std::vector<pkgAcquire::Item *> const &ItmOwners,
+				 pkgAcquire::MethodConfig *const Config, pkgAcquireStatus *const Log,
+				 std::string const &Message, bool const errTransient, bool const errAuthErr);
+};
+
+/** @} */
+
+#endif
diff --git a/apt-pkg/acquire.cc b/apt-pkg/acquire.cc
new file mode 100644
index 0000000..cdb2c52
--- /dev/null
+++ b/apt-pkg/acquire.cc
@@ -0,0 +1,1570 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire - File Acquiration
+
+   The core element for the schedule system is the concept of a named
+   queue. Each queue is unique and each queue has a name derived from the
+   URI. The degree of paralization can be controlled by how the queue
+   name is derived from the URI.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/acquire-worker.h>
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <chrono>
+#include <cmath>
+#include <iomanip>
+#include <iostream>
+#include <memory>
+#include <numeric>
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// helper to convert time_point to a timeval
+constexpr struct timeval SteadyDurationToTimeVal(std::chrono::steady_clock::duration Time)
+{
+   auto const Time_sec = std::chrono::duration_cast<std::chrono::seconds>(Time);
+   auto const Time_usec = std::chrono::duration_cast<std::chrono::microseconds>(Time - Time_sec);
+   return timeval{static_cast<time_t>(Time_sec.count()), static_cast<suseconds_t>(Time_usec.count())};
+}
+
+std::string pkgAcquire::URIEncode(std::string const &part)		/*{{{*/
+{
+   // The "+" is encoded as a workaround for an S3 bug (LP#1003633 and LP#1086997)
+   return QuoteString(part, _config->Find("Acquire::URIEncode", "+~ ").c_str());
+}
+									/*}}}*/
+// Acquire::pkgAcquire - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* We grab some runtime state from the configuration space */
+pkgAcquire::pkgAcquire() : LockFD(-1), d(NULL), Queues(0), Workers(0), Configs(0), Log(NULL), ToFetch(0),
+			   Debug(_config->FindB("Debug::pkgAcquire",false)),
+			   Running(false)
+{
+   Initialize();
+}
+pkgAcquire::pkgAcquire(pkgAcquireStatus *Progress) : LockFD(-1), d(NULL), Queues(0), Workers(0),
+			   Configs(0), Log(NULL), ToFetch(0),
+			   Debug(_config->FindB("Debug::pkgAcquire",false)),
+			   Running(false)
+{
+   Initialize();
+   SetLog(Progress);
+}
+void pkgAcquire::Initialize()
+{
+   string const Mode = _config->Find("Acquire::Queue-Mode","host");
+   if (strcasecmp(Mode.c_str(),"host") == 0)
+      QueueMode = QueueHost;
+   if (strcasecmp(Mode.c_str(),"access") == 0)
+      QueueMode = QueueAccess;
+}
+									/*}}}*/
+// Acquire::GetLock - lock directory and prepare for action		/*{{{*/
+static bool SetupAPTPartialDirectory(std::string const &grand, std::string const &parent, std::string const &postfix, mode_t const mode)
+{
+   if (_config->FindB("Debug::SetupAPTPartialDirectory::AssumeGood", false))
+      return true;
+   std::string const partial = parent + postfix;
+   bool const partialExists = DirectoryExists(partial);
+   if (partialExists == false)
+   {
+      mode_t const old_umask = umask(S_IWGRP | S_IWOTH);
+      bool const creation_fail = (CreateAPTDirectoryIfNeeded(grand, partial) == false &&
+	    CreateAPTDirectoryIfNeeded(parent, partial) == false);
+      umask(old_umask);
+      if (creation_fail == true)
+	 return false;
+   }
+
+   std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+   if (getuid() == 0)
+   {
+      if (SandboxUser.empty() == false && SandboxUser != "root") // if we aren't root, we can't chown, so don't try it
+      {
+	 struct passwd const * const pw = getpwnam(SandboxUser.c_str());
+	 struct group const * const gr = getgrnam(ROOT_GROUP);
+	 if (pw != NULL && gr != NULL)
+	 {
+	    // chown the partial dir
+	    if(chown(partial.c_str(), pw->pw_uid, gr->gr_gid) != 0)
+	       _error->WarningE("SetupAPTPartialDirectory", "chown to %s:%s of directory %s failed", SandboxUser.c_str(), ROOT_GROUP, partial.c_str());
+	 }
+      }
+      if (chmod(partial.c_str(), mode) != 0)
+	 _error->WarningE("SetupAPTPartialDirectory", "chmod 0%03o of directory %s failed", mode, partial.c_str());
+
+   }
+   else if (chmod(partial.c_str(), mode) != 0)
+   {
+      // if we haven't created the dir and aren't root, it is kinda expected that chmod doesn't work
+      if (partialExists == false)
+	 _error->WarningE("SetupAPTPartialDirectory", "chmod 0%03o of directory %s failed", mode, partial.c_str());
+   }
+
+   _error->PushToStack();
+   // remove 'old' FAILED files to stop us from collecting them for no reason
+   for (auto const &Failed: GetListOfFilesInDir(partial, "FAILED", false, false))
+      RemoveFile("SetupAPTPartialDirectory", Failed);
+   _error->RevertToStack();
+
+   return true;
+}
+bool pkgAcquire::GetLock(std::string const &Lock)
+{
+   if (Lock.empty() == true)
+      return false;
+
+   // check for existence and possibly create auxiliary directories
+   string const listDir = _config->FindDir("Dir::State::lists");
+   string const archivesDir = _config->FindDir("Dir::Cache::Archives");
+
+   if (Lock == listDir)
+   {
+      if (SetupAPTPartialDirectory(_config->FindDir("Dir::State"), listDir, "partial", 0700) == false)
+	 return _error->Errno("Acquire", _("List directory %s is missing."), (listDir + "partial").c_str());
+   }
+   if (Lock == archivesDir)
+   {
+      if (SetupAPTPartialDirectory(_config->FindDir("Dir::Cache"), archivesDir, "partial", 0700) == false)
+	 return _error->Errno("Acquire", _("Archives directory %s is missing."), (archivesDir + "partial").c_str());
+   }
+   if (Lock == listDir || Lock == archivesDir)
+   {
+      if (SetupAPTPartialDirectory(_config->FindDir("Dir::State"), listDir, "auxfiles", 0755) == false)
+      {
+	 // not being able to create lists/auxfiles isn't critical as we will use a tmpdir then
+      }
+   }
+
+   if (_config->FindB("Debug::NoLocking", false) == true)
+      return true;
+
+   // Lock the directory this acquire object will work in
+   if (LockFD != -1)
+      close(LockFD);
+   LockFD = ::GetLock(flCombine(Lock, "lock"));
+   if (LockFD == -1)
+      return _error->Error(_("Unable to lock directory %s"), Lock.c_str());
+
+   return true;
+}
+									/*}}}*/
+// Acquire::~pkgAcquire	- Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* Free our memory, clean up the queues (destroy the workers) */
+pkgAcquire::~pkgAcquire()
+{
+   Shutdown();
+
+   if (LockFD != -1)
+      close(LockFD);
+
+   while (Configs != 0)
+   {
+      MethodConfig *Jnk = Configs;
+      Configs = Configs->Next;
+      delete Jnk;
+   }   
+}
+									/*}}}*/
+// Acquire::Shutdown - Clean out the acquire object			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgAcquire::Shutdown()
+{
+   while (Items.empty() == false)
+   {
+      if (Items[0]->Status == Item::StatFetching)
+         Items[0]->Status = Item::StatError;
+      delete Items[0];
+   }
+
+   while (Queues != 0)
+   {
+      Queue *Jnk = Queues;
+      Queues = Queues->Next;
+      delete Jnk;
+   }   
+}
+									/*}}}*/
+// Acquire::Add - Add a new item					/*{{{*/
+// ---------------------------------------------------------------------
+/* This puts an item on the acquire list. This list is mainly for tracking
+   item status */
+void pkgAcquire::Add(Item *Itm)
+{
+   Items.push_back(Itm);
+}
+									/*}}}*/
+// Acquire::Remove - Remove a item					/*{{{*/
+// ---------------------------------------------------------------------
+/* Remove an item from the acquire list. This is usually not used.. */
+void pkgAcquire::Remove(Item *Itm)
+{
+   Dequeue(Itm);
+   
+   for (ItemIterator I = Items.begin(); I != Items.end();)
+   {
+      if (*I == Itm)
+      {
+	 Items.erase(I);
+	 I = Items.begin();
+      }      
+      else 
+	 ++I;
+   }
+}
+									/*}}}*/
+// Acquire::Add - Add a worker						/*{{{*/
+// ---------------------------------------------------------------------
+/* A list of workers is kept so that the select loop can direct their FD
+   usage. */
+void pkgAcquire::Add(Worker *Work)
+{
+   Work->NextAcquire = Workers;
+   Workers = Work;
+}
+									/*}}}*/
+// Acquire::Remove - Remove a worker					/*{{{*/
+// ---------------------------------------------------------------------
+/* A worker has died. This can not be done while the select loop is running
+   as it would require that RunFds could handling a changing list state and
+   it can't.. */
+void pkgAcquire::Remove(Worker *Work)
+{
+   if (Running == true)
+      abort();
+   
+   Worker **I = &Workers;
+   for (; *I != 0;)
+   {
+      if (*I == Work)
+	 *I = (*I)->NextAcquire;
+      else
+	 I = &(*I)->NextAcquire;
+   }
+}
+									/*}}}*/
+// Acquire::Enqueue - Queue an URI for fetching				/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the entry point for an item. An item calls this function when
+   it is constructed which creates a queue (based on the current queue
+   mode) and puts the item in that queue. If the system is running then
+   the queue might be started. */
+static bool CheckForBadItemAndFailIt(pkgAcquire::Item * const Item,
+      pkgAcquire::MethodConfig const * const Config, pkgAcquireStatus * const Log)
+{
+   auto SavedDesc = Item->GetItemDesc();
+   if (Item->IsRedirectionLoop(SavedDesc.URI))
+   {
+      std::string const Message = "400 URI Failure"
+	 "\nURI: " + SavedDesc.URI +
+	 "\nFilename: " + Item->DestFile +
+	 "\nFailReason: RedirectionLoop";
+
+      Item->Status = pkgAcquire::Item::StatError;
+      Item->Failed(Message, Config);
+      if (Log != nullptr)
+	 Log->Fail(SavedDesc);
+      return true;
+   }
+
+   HashStringList const hsl = Item->GetExpectedHashes();
+   if (hsl.usable() == false && Item->HashesRequired() &&
+	 _config->Exists("Acquire::ForceHash") == false)
+   {
+      std::string const Message = "400 URI Failure"
+	 "\nURI: " + SavedDesc.URI +
+	 "\nFilename: " + Item->DestFile +
+	 "\nFailReason: WeakHashSums";
+
+      Item->Status = pkgAcquire::Item::StatAuthError;
+      Item->Failed(Message, Config);
+      if (Log != nullptr)
+	 Log->Fail(SavedDesc);
+      return true;
+   }
+   return false;
+}
+void pkgAcquire::Enqueue(ItemDesc &Item)
+{
+   // Determine which queue to put the item in
+   const MethodConfig *Config = nullptr;
+   string Name = QueueName(Item.URI,Config);
+   if (Name.empty() == true)
+   {
+      Item.Owner->Status = pkgAcquire::Item::StatError;
+      return;
+   }
+
+   /* the check for running avoids that we produce errors
+      in logging before we actually have started, which would
+      be easier to implement but would confuse users/implementations
+      so we check the items skipped here in #Startup */
+   if (Running && CheckForBadItemAndFailIt(Item.Owner, Config, Log))
+      return;
+
+   // Find the queue structure
+   Queue *I = Queues;
+   for (; I != 0 && I->Name != Name; I = I->Next);
+   if (I == 0)
+   {
+      I = new Queue(Name,this);
+      I->Next = Queues;
+      Queues = I;
+      
+      if (Running == true)
+	 I->Startup();
+   }
+
+   // See if this is a local only URI
+   if (Config->LocalOnly == true && Item.Owner->Complete == false)
+      Item.Owner->Local = true;
+   Item.Owner->Status = Item::StatIdle;
+   
+   // Queue it into the named queue
+   if(I->Enqueue(Item)) 
+      ToFetch++;
+            
+   // Some trace stuff
+   if (Debug == true)
+   {
+      clog << "Fetching " << Item.URI << endl;
+      clog << " to " << Item.Owner->DestFile << endl;
+      clog << " Queue is: " << Name << endl;
+   }
+}
+									/*}}}*/
+// Acquire::Dequeue - Remove an item from all queues			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called when an item is finished being fetched. It removes it
+   from all the queues */
+void pkgAcquire::Dequeue(Item *Itm)
+{
+   Queue *I = Queues;
+   bool Res = false;
+   if (Debug == true)
+      clog << "Dequeuing " << Itm->DestFile << endl;
+
+   for (; I != 0; I = I->Next)
+   {
+      if (I->Dequeue(Itm))
+      {
+         Res = true;
+	 if (Debug == true)
+	    clog << "Dequeued from " << I->Name << endl;
+      }
+   }
+
+   if (Res == true)
+      ToFetch--;
+}
+									/*}}}*/
+// Acquire::QueueName - Return the name of the queue for this URI	/*{{{*/
+// ---------------------------------------------------------------------
+/* The string returned depends on the configuration settings and the
+   method parameters. Given something like http://foo.org/bar it can
+   return http://foo.org or http */
+string pkgAcquire::QueueName(string Uri,MethodConfig const *&Config)
+{
+   constexpr int DEFAULT_HOST_LIMIT = 10;
+   URI U(Uri);
+
+   // Note that this gets written through the reference to the caller.
+   Config = GetConfig(U.Access);
+   if (Config == nullptr)
+      return {};
+
+   // Access mode forces all methods to be Single-Instance
+   if (QueueMode == QueueAccess)
+      return U.Access;
+
+   // Single-Instance methods get exactly one queue per URI
+   if (Config->SingleInstance == true)
+      return U.Access;
+
+   // Host-less methods like rred, store, …
+   if (U.Host.empty())
+   {
+      int existing = 0;
+      // check how many queues exist already and reuse empty ones
+      auto const AccessSchema = U.Access + ':';
+      for (Queue const *I = Queues; I != 0; I = I->Next)
+	 if (APT::String::Startswith(I->Name, AccessSchema))
+	 {
+	    if (I->Items == nullptr)
+	       return I->Name;
+	    ++existing;
+	 }
+
+      int const Limit = _config->FindI("Acquire::QueueHost::Limit",
+#ifdef _SC_NPROCESSORS_ONLN
+	    sysconf(_SC_NPROCESSORS_ONLN) * 2
+#else
+	    DEFAULT_HOST_LIMIT
+#endif
+      );
+
+      // create a new worker if we don't have too many yet
+      if (Limit <= 0 || existing < Limit)
+	 return AccessSchema + std::to_string(existing);
+
+      // find the worker with the least to do
+      // we already established that there are no empty and we can't spawn new
+      Queue const *selected = nullptr;
+      auto selected_backlog = std::numeric_limits<decltype(HashStringList().FileSize())>::max();
+      for (Queue const *Q = Queues; Q != nullptr; Q = Q->Next)
+	 if (APT::String::Startswith(Q->Name, AccessSchema))
+	 {
+	    decltype(selected_backlog) current_backlog = 0;
+	    for (auto const *I = Q->Items; I != nullptr; I = I->Next)
+	    {
+	       auto const hashes = I->Owner->GetExpectedHashes();
+	       if (not hashes.empty())
+		  current_backlog += hashes.FileSize();
+	       else
+		  current_backlog += I->Owner->FileSize;
+	    }
+	    if (current_backlog < selected_backlog)
+	    {
+	       selected = Q;
+	       selected_backlog = current_backlog;
+	    }
+	 }
+
+      if (unlikely(selected == nullptr))
+	 return AccessSchema + "0";
+      return selected->Name;
+   }
+   // most methods talking to remotes like http
+   else
+   {
+      auto const FullQueueName = U.Access + ':' + U.Host;
+      // if the queue already exists, re-use it
+      for (Queue const *Q = Queues; Q != nullptr; Q = Q->Next)
+	 if (Q->Name == FullQueueName)
+	    return FullQueueName;
+
+      int existing = 0;
+      // check how many queues exist already and reuse empty ones
+      auto const AccessSchema = U.Access + ':';
+      for (Queue const *Q = Queues; Q != nullptr; Q = Q->Next)
+	 if (APT::String::Startswith(Q->Name, AccessSchema))
+	    ++existing;
+
+      int const Limit = _config->FindI("Acquire::QueueHost::Limit", DEFAULT_HOST_LIMIT);
+      // if we have too many hosts open use a single generic for the rest
+      if (existing >= Limit)
+	 return U.Access;
+
+      // we can still create new named queues
+      return FullQueueName;
+   }
+}
+									/*}}}*/
+// Acquire::GetConfig - Fetch the configuration information		/*{{{*/
+// ---------------------------------------------------------------------
+/* This locates the configuration structure for an access method. If 
+   a config structure cannot be found a Worker will be created to
+   retrieve it */
+pkgAcquire::MethodConfig *pkgAcquire::GetConfig(string Access)
+{
+   // Search for an existing config
+   MethodConfig *Conf;
+   for (Conf = Configs; Conf != 0; Conf = Conf->Next)
+      if (Conf->Access == Access)
+	 return Conf;
+   
+   // Create the new config class
+   Conf = new MethodConfig;
+   Conf->Access = Access;
+
+   // Create the worker to fetch the configuration
+   Worker Work(Conf);
+   if (Work.Start() == false)
+   {
+      delete Conf;
+      return nullptr;
+   }
+   Conf->Next = Configs;
+   Configs = Conf;
+
+   /* if a method uses DownloadLimit, we switch to SingleInstance mode */
+   if(_config->FindI("Acquire::"+Access+"::Dl-Limit",0) > 0)
+      Conf->SingleInstance = true;
+    
+   return Conf;
+}
+									/*}}}*/
+// Acquire::SetFds - Deal with readable FDs				/*{{{*/
+// ---------------------------------------------------------------------
+/* Collect FDs that have activity monitors into the fd sets */
+void pkgAcquire::SetFds(int &Fd,fd_set *RSet,fd_set *WSet)
+{
+   for (Worker *I = Workers; I != 0; I = I->NextAcquire)
+   {
+      if (I->InReady == true && I->InFd >= 0)
+      {
+	 if (Fd < I->InFd)
+	    Fd = I->InFd;
+	 FD_SET(I->InFd,RSet);
+      }
+      if (I->OutReady == true && I->OutFd >= 0)
+      {
+	 if (Fd < I->OutFd)
+	    Fd = I->OutFd;
+	 FD_SET(I->OutFd,WSet);
+      }
+   }
+}
+									/*}}}*/
+// Acquire::RunFds - Deal with active FDs				/*{{{*/
+// ---------------------------------------------------------------------
+/* Dispatch active FDs over to the proper workers. It is very important
+   that a worker never be erased while this is running! The queue class
+   should never erase a worker except during shutdown processing. */
+bool pkgAcquire::RunFds(fd_set *RSet,fd_set *WSet)
+{
+   bool Res = true;
+
+   for (Worker *I = Workers; I != 0; I = I->NextAcquire)
+   {
+      if (I->InFd >= 0 && FD_ISSET(I->InFd,RSet) != 0)
+	 Res &= I->InFdReady();
+      if (I->OutFd >= 0 && FD_ISSET(I->OutFd,WSet) != 0)
+	 Res &= I->OutFdReady();
+   }
+
+   return Res;
+}
+									/*}}}*/
+// Acquire::Run - Run the fetch sequence				/*{{{*/
+// ---------------------------------------------------------------------
+/* This runs the queues. It manages a select loop for all of the
+   Worker tasks. The workers interact with the queues and items to
+   manage the actual fetch. */
+static bool IsAccessibleBySandboxUser(std::string const &filename, bool const ReadWrite)
+{
+   // you would think this is easily to answer with faccessat, right? Wrong!
+   // It e.g. gets groups wrong, so the only thing which works reliable is trying
+   // to open the file we want to open later on…
+   if (unlikely(filename.empty()))
+      return true;
+
+   if (ReadWrite == false)
+   {
+      errno = 0;
+      // can we read a file? Note that non-existing files are "fine"
+      int const fd = open(filename.c_str(), O_RDONLY | O_CLOEXEC);
+      if (fd == -1 && errno == EACCES)
+	 return false;
+      close(fd);
+      return true;
+   }
+   else
+   {
+      // the file might not exist yet and even if it does we will fix permissions,
+      // so important is here just that the directory it is in allows that
+      std::string const dirname = flNotFile(filename);
+      if (unlikely(dirname.empty()))
+	 return true;
+
+      char const * const filetag = ".apt-acquire-privs-test.XXXXXX";
+      std::string const tmpfile_tpl = flCombine(dirname, filetag);
+      std::unique_ptr<char, decltype(std::free) *> tmpfile { strdup(tmpfile_tpl.c_str()), std::free };
+      int const fd = mkstemp(tmpfile.get());
+      if (fd == -1 && errno == EACCES)
+	 return false;
+      RemoveFile("IsAccessibleBySandboxUser", tmpfile.get());
+      close(fd);
+      return true;
+   }
+}
+static void CheckDropPrivsMustBeDisabled(pkgAcquire const &Fetcher)
+{
+   if(getuid() != 0)
+      return;
+
+   std::string const SandboxUser = _config->Find("APT::Sandbox::User");
+   if (SandboxUser.empty() || SandboxUser == "root")
+      return;
+
+   struct passwd const * const pw = getpwnam(SandboxUser.c_str());
+   if (pw == NULL)
+   {
+      _error->Warning(_("No sandbox user '%s' on the system, can not drop privileges"), SandboxUser.c_str());
+      _config->Set("APT::Sandbox::User", "");
+      return;
+   }
+
+   gid_t const old_euid = geteuid();
+   gid_t const old_egid = getegid();
+
+   long const ngroups_max = sysconf(_SC_NGROUPS_MAX);
+   std::unique_ptr<gid_t[]> old_gidlist(new gid_t[ngroups_max]);
+   if (unlikely(old_gidlist == NULL))
+      return;
+   ssize_t old_gidlist_nr;
+   if ((old_gidlist_nr = getgroups(ngroups_max, old_gidlist.get())) < 0)
+   {
+      _error->FatalE("getgroups", "getgroups %lu failed", ngroups_max);
+      old_gidlist[0] = 0;
+      old_gidlist_nr = 1;
+   }
+   if (setgroups(1, &pw->pw_gid))
+      _error->FatalE("setgroups", "setgroups %u failed", pw->pw_gid);
+
+   if (setegid(pw->pw_gid) != 0)
+      _error->FatalE("setegid", "setegid %u failed", pw->pw_gid);
+   if (seteuid(pw->pw_uid) != 0)
+      _error->FatalE("seteuid", "seteuid %u failed", pw->pw_uid);
+
+   for (pkgAcquire::ItemCIterator I = Fetcher.ItemsBegin();
+	I != Fetcher.ItemsEnd(); ++I)
+   {
+      // no need to drop privileges for a complete file
+      if ((*I)->Complete == true || (*I)->Status != pkgAcquire::Item::StatIdle)
+	 continue;
+
+      // if destination file is inaccessible all hope is lost for privilege dropping
+      if (IsAccessibleBySandboxUser((*I)->DestFile, true) == false)
+      {
+	 _error->WarningE("pkgAcquire::Run", _("Download is performed unsandboxed as root as file '%s' couldn't be accessed by user '%s'."),
+	       (*I)->DestFile.c_str(), SandboxUser.c_str());
+	 _config->Set("APT::Sandbox::User", "");
+	 break;
+      }
+
+      // if its the source file (e.g. local sources) we might be lucky
+      // by dropping the dropping only for some methods.
+      URI const source((*I)->DescURI());
+      if (source.Access == "file" || source.Access == "copy")
+      {
+	 std::string const conf = "Binary::" + source.Access + "::APT::Sandbox::User";
+	 if (_config->Exists(conf) == true)
+	    continue;
+
+	 auto const filepath = DeQuoteString(source.Path);
+	 if (not IsAccessibleBySandboxUser(filepath, false))
+	 {
+	    _error->NoticeE("pkgAcquire::Run", _("Download is performed unsandboxed as root as file '%s' couldn't be accessed by user '%s'."),
+			    filepath.c_str(), SandboxUser.c_str());
+	    _config->CndSet("Binary::file::APT::Sandbox::User", "root");
+	    _config->CndSet("Binary::copy::APT::Sandbox::User", "root");
+	 }
+      }
+   }
+
+   if (seteuid(old_euid) != 0)
+      _error->FatalE("seteuid", "seteuid %u failed", old_euid);
+   if (setegid(old_egid) != 0)
+      _error->FatalE("setegid", "setegid %u failed", old_egid);
+   if (setgroups(old_gidlist_nr, old_gidlist.get()))
+      _error->FatalE("setgroups", "setgroups %u failed", 0);
+}
+pkgAcquire::RunResult pkgAcquire::Run(int PulseInterval)
+{
+   _error->PushToStack();
+   CheckDropPrivsMustBeDisabled(*this);
+
+   Running = true;
+
+   if (Log != 0)
+      Log->Start();
+
+   for (Queue *I = Queues; I != 0; I = I->Next)
+      I->Startup();
+   
+   bool WasCancelled = false;
+
+   // Run till all things have been acquired
+   struct timeval tv = SteadyDurationToTimeVal(std::chrono::microseconds(PulseInterval));
+   while (ToFetch > 0)
+   {
+      fd_set RFds;
+      fd_set WFds;
+      int Highest = 0;
+      FD_ZERO(&RFds);
+      FD_ZERO(&WFds);
+      SetFds(Highest,&RFds,&WFds);
+
+      // Shorten the select() cycle in case we have items about to become ready
+      auto now = clock::now();
+      auto fetchAfter = time_point{};
+      for (Queue *I = Queues; I != nullptr; I = I->Next)
+      {
+	 if (I->Items == nullptr)
+	    continue;
+
+	 auto f = I->Items->GetFetchAfter();
+
+	 if (f == time_point() || I->Items->Owner->Status != pkgAcquire::Item::StatIdle)
+	    continue;
+
+	 if (f <= now)
+	 {
+	    if (not I->Cycle()) // Queue got stuck, unstuck it.
+	       goto stop;
+	    fetchAfter = now; // need to time out in select() below
+	    if (I->Items->Owner->Status == pkgAcquire::Item::StatIdle)
+	    {
+	       _error->Warning("Tried to start delayed item %s, but failed", I->Items->Description.c_str());
+	    }
+	 }
+	 else if (f < fetchAfter || fetchAfter == time_point{})
+	 {
+	    fetchAfter = f;
+	 }
+      }
+
+      if (fetchAfter != time_point{} && (fetchAfter - now) < std::chrono::seconds(tv.tv_sec) + std::chrono::microseconds(tv.tv_usec))
+      {
+	 tv = SteadyDurationToTimeVal(fetchAfter - now);
+      }
+
+      int Res;
+      do
+      {
+	 Res = select(Highest+1,&RFds,&WFds,0,&tv);
+      }
+      while (Res < 0 && errno == EINTR);
+      
+      if (Res < 0)
+      {
+	 _error->Errno("select","Select has failed");
+	 break;
+      }
+
+      if(RunFds(&RFds,&WFds) == false)
+         break;
+
+      // Timeout, notify the log class
+      if (Res == 0 || (Log != 0 && Log->Update == true))
+      {
+	 tv = SteadyDurationToTimeVal(std::chrono::microseconds(PulseInterval));
+
+	 for (Worker *I = Workers; I != 0; I = I->NextAcquire)
+	    I->Pulse();
+	 if (Log != 0 && Log->Pulse(this) == false)
+	 {
+	    WasCancelled = true;
+	    break;
+	 }
+      }      
+   }
+stop:
+   if (Log != 0)
+      Log->Stop();
+   
+   // Shut down the acquire bits
+   Running = false;
+   for (Queue *I = Queues; I != 0; I = I->Next)
+      I->Shutdown(false);
+
+   // Shut down the items
+   for (ItemIterator I = Items.begin(); I != Items.end(); ++I)
+      (*I)->Finished();
+
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   if (newError)
+      return Failed;
+   if (WasCancelled)
+      return Cancelled;
+   return Continue;
+}
+									/*}}}*/
+// Acquire::Bump - Called when an item is dequeued			/*{{{*/
+// ---------------------------------------------------------------------
+/* This routine bumps idle queues in hopes that they will be able to fetch
+   the dequeued item */
+void pkgAcquire::Bump()
+{
+   for (Queue *I = Queues; I != 0; I = I->Next)
+      I->Bump();
+}
+									/*}}}*/
+// Acquire::WorkerStep - Step to the next worker			/*{{{*/
+// ---------------------------------------------------------------------
+/* Not inlined to advoid including acquire-worker.h */
+pkgAcquire::Worker *pkgAcquire::WorkerStep(Worker *I)
+{
+   return I->NextAcquire;
+}
+									/*}}}*/
+// Acquire::Clean - Cleans a directory					/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a bit simplistic, it looks at every file in the dir and sees
+   if it is part of the download set. */
+bool pkgAcquire::Clean(string Dir)
+{
+   // non-existing directories are by definition clean…
+   if (DirectoryExists(Dir) == false)
+      return true;
+
+   if(Dir == "/")
+      return _error->Error(_("Clean of %s is not supported"), Dir.c_str());
+
+   int const dirfd = open(Dir.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+   if (dirfd == -1)
+      return _error->Errno("open",_("Unable to read %s"),Dir.c_str());
+   DIR * const D = fdopendir(dirfd);
+   if (D == nullptr)
+      return _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
+
+   for (struct dirent *E = readdir(D); E != nullptr; E = readdir(D))
+   {
+      // Skip some entries
+      if (strcmp(E->d_name, "lock") == 0 ||
+	  strcmp(E->d_name, "partial") == 0 ||
+	  strcmp(E->d_name, "auxfiles") == 0 ||
+	  strcmp(E->d_name, "lost+found") == 0 ||
+	  strcmp(E->d_name, ".") == 0 ||
+	  strcmp(E->d_name, "..") == 0)
+	 continue;
+
+      // Look in the get list and if not found nuke
+      if (std::any_of(Items.cbegin(), Items.cend(),
+	     [&E](pkgAcquire::Item const * const I) {
+		return flNotDir(I->DestFile) == E->d_name;
+	     }) == false)
+      {
+	 RemoveFileAt("pkgAcquire::Clean", dirfd, E->d_name);
+      }
+   }
+   closedir(D);
+   return true;
+}
+									/*}}}*/
+// Acquire::TotalNeeded - Number of bytes to fetch			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the total number of bytes needed */
+APT_PURE unsigned long long pkgAcquire::TotalNeeded()
+{
+   return std::accumulate(ItemsBegin(), ItemsEnd(), 0llu,
+      [](unsigned long long const T, Item const * const I) {
+	 return T + I->FileSize;
+   });
+}
+									/*}}}*/
+// Acquire::FetchNeeded - Number of bytes needed to get			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the number of bytes that is not local */
+APT_PURE unsigned long long pkgAcquire::FetchNeeded()
+{
+   return std::accumulate(ItemsBegin(), ItemsEnd(), 0llu,
+      [](unsigned long long const T, Item const * const I) {
+	 if (I->Local == false)
+	    return T + I->FileSize;
+	 else
+	    return T;
+   });
+}
+									/*}}}*/
+// Acquire::PartialPresent - Number of partial bytes we already have	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the number of bytes that is not local */
+APT_PURE unsigned long long pkgAcquire::PartialPresent()
+{
+   return std::accumulate(ItemsBegin(), ItemsEnd(), 0llu,
+      [](unsigned long long const T, Item const * const I) {
+	 if (I->Local == false)
+	    return T + I->PartialSize;
+	 else
+	    return T;
+   });
+}
+									/*}}}*/
+// Acquire::UriBegin - Start iterator for the uri list			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::UriIterator pkgAcquire::UriBegin()
+{
+   return UriIterator(Queues);
+}
+									/*}}}*/
+// Acquire::UriEnd - End iterator for the uri list			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::UriIterator pkgAcquire::UriEnd()
+{
+   return UriIterator(0);
+}
+									/*}}}*/
+// Acquire::MethodConfig::MethodConfig - Constructor			/*{{{*/
+class pkgAcquire::MethodConfig::Private
+{
+   public:
+   bool AuxRequests = false;
+   bool SendURIEncoded = false;
+};
+pkgAcquire::MethodConfig::MethodConfig() : d(new Private()), Next(0), SingleInstance(false),
+					   Pipeline(false), SendConfig(false), LocalOnly(false), NeedsCleanup(false),
+					   Removable(false)
+{
+}
+									/*}}}*/
+bool pkgAcquire::MethodConfig::GetAuxRequests() const /*{{{*/
+{
+   return d->AuxRequests;
+}
+									/*}}}*/
+void pkgAcquire::MethodConfig::SetAuxRequests(bool const value) /*{{{*/
+{
+   d->AuxRequests = value;
+}
+									/*}}}*/
+bool pkgAcquire::MethodConfig::GetSendURIEncoded() const		/*{{{*/
+{
+   return d->SendURIEncoded;
+}
+									/*}}}*/
+void pkgAcquire::MethodConfig::SetSendURIEncoded(bool const value)	/*{{{*/
+{
+   d->SendURIEncoded = value;
+}
+									/*}}}*/
+
+// Queue::Queue - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::Queue::Queue(string const &name,pkgAcquire * const owner) : d(NULL), Next(0),
+   Name(name), Items(0), Workers(0), Owner(owner), PipeDepth(0), MaxPipeDepth(1)
+{
+}
+									/*}}}*/
+// Queue::~Queue - Destructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::Queue::~Queue()
+{
+   Shutdown(true);
+   
+   while (Items != 0)
+   {
+      QItem *Jnk = Items;
+      Items = Items->Next;
+      delete Jnk;
+   }
+}
+									/*}}}*/
+// Queue::Enqueue - Queue an item to the queue				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::Queue::Enqueue(ItemDesc &Item)
+{
+   // MetaKeysMatch checks whether the two items have no non-matching
+   // meta-keys. If the items are not transaction items, it returns
+   // true, so other items can still be merged.
+   auto MetaKeysMatch = [](pkgAcquire::ItemDesc const &A, pkgAcquire::Queue::QItem const *B) {
+      auto OwnerA = dynamic_cast<pkgAcqTransactionItem*>(A.Owner);
+      if (OwnerA == nullptr)
+	 return true;
+
+      for (auto const & OwnerBUncast : B->Owners) {
+	 auto OwnerB = dynamic_cast<pkgAcqTransactionItem*>(OwnerBUncast);
+
+	 if (OwnerB != nullptr && OwnerA->GetMetaKey() != OwnerB->GetMetaKey())
+	    return false;
+      }
+      return true;
+   };
+   QItem **OptimalI = &Items;
+   QItem **I = &Items;
+   auto insertLocation = std::make_tuple(Item.Owner->FetchAfter(), -Item.Owner->Priority());
+   // move to the end of the queue and check for duplicates here
+   for (; *I != 0; ) {
+      if (Item.URI == (*I)->URI && MetaKeysMatch(Item, *I))
+      {
+	 if (_config->FindB("Debug::pkgAcquire::Worker",false) == true)
+	    std::cerr << " @ Queue: Action combined for " << Item.URI << " and " << (*I)->URI << std::endl;
+	 (*I)->Owners.push_back(Item.Owner);
+	 Item.Owner->Status = (*I)->Owner->Status;
+	 return false;
+      }
+      // Determine the optimal position to insert: before anything with a
+      // higher priority.
+      auto queueLocation = std::make_tuple((*I)->GetFetchAfter(),
+					   -(*I)->GetPriority());
+
+      I = &(*I)->Next;
+      if (queueLocation <= insertLocation)
+      {
+	 OptimalI = I;
+      }
+   }
+
+
+   // Create a new item
+   QItem *Itm = new QItem;
+   *Itm = Item;
+   Itm->Next = *OptimalI;
+   *OptimalI = Itm;
+   
+   Item.Owner->QueueCounter++;   
+   if (Items->Next == 0)
+      Cycle();
+   return true;
+}
+									/*}}}*/
+// Queue::Dequeue - Remove an item from the queue			/*{{{*/
+// ---------------------------------------------------------------------
+/* We return true if we hit something */
+bool pkgAcquire::Queue::Dequeue(Item *Owner)
+{
+   if (Owner->Status == pkgAcquire::Item::StatFetching)
+      return _error->Error("Tried to dequeue a fetching object");
+
+   bool Res = false;
+
+   QItem **I = &Items;
+   for (; *I != 0;)
+   {
+      if (Owner == (*I)->Owner)
+      {
+	 QItem *Jnk= *I;
+	 *I = (*I)->Next;
+	 Owner->QueueCounter--;
+	 delete Jnk;
+	 Res = true;
+      }
+      else
+	 I = &(*I)->Next;
+   }
+
+   return Res;
+}
+									/*}}}*/
+// Queue::Startup - Start the worker processes				/*{{{*/
+// ---------------------------------------------------------------------
+/* It is possible for this to be called with a pre-existing set of
+   workers. */
+bool pkgAcquire::Queue::Startup()
+{
+   if (Workers == 0)
+   {
+      URI U(Name);
+      pkgAcquire::MethodConfig * const Cnf = Owner->GetConfig(U.Access);
+      if (unlikely(Cnf == nullptr))
+	 return false;
+
+      // now-running twin of the pkgAcquire::Enqueue call
+      for (QItem *I = Items; I != 0; )
+      {
+	 auto const INext = I->Next;
+	 for (auto &&O: I->Owners)
+	    CheckForBadItemAndFailIt(O, Cnf, Owner->Log);
+	 // if an item failed, it will be auto-dequeued invalidation our I here
+	 I = INext;
+      }
+
+      Workers = new Worker(this,Cnf,Owner->Log);
+      Owner->Add(Workers);
+      if (Workers->Start() == false)
+	 return false;
+      
+      /* When pipelining we commit 10 items. This needs to change when we
+         added other source retry to have cycle maintain a pipeline depth
+         on its own. */
+      if (Cnf->Pipeline == true)
+	 MaxPipeDepth = _config->FindI("Acquire::Max-Pipeline-Depth",10);
+      else
+	 MaxPipeDepth = 1;
+   }
+   
+   return Cycle();
+}
+									/*}}}*/
+// Queue::Shutdown - Shutdown the worker processes			/*{{{*/
+// ---------------------------------------------------------------------
+/* If final is true then all workers are eliminated, otherwise only workers
+   that do not need cleanup are removed */
+bool pkgAcquire::Queue::Shutdown(bool Final)
+{
+   // Delete all of the workers
+   pkgAcquire::Worker **Cur = &Workers;
+   while (*Cur != 0)
+   {
+      pkgAcquire::Worker *Jnk = *Cur;
+      if (Final == true || Jnk->GetConf()->NeedsCleanup == false)
+      {
+	 *Cur = Jnk->NextQueue;
+	 Owner->Remove(Jnk);
+	 delete Jnk;
+      }
+      else
+	 Cur = &(*Cur)->NextQueue;      
+   }
+   
+   return true;
+}
+									/*}}}*/
+// Queue::FindItem - Find a URI in the item list			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquire::Queue::QItem *pkgAcquire::Queue::FindItem(string URI,pkgAcquire::Worker *Owner)
+{
+   if (Owner->Config->GetSendURIEncoded())
+   {
+      for (QItem *I = Items; I != nullptr; I = I->Next)
+	 if (I->URI == URI && I->Worker == Owner)
+	    return I;
+   }
+   else
+   {
+      for (QItem *I = Items; I != nullptr; I = I->Next)
+      {
+	 if (I->Worker != Owner)
+	    continue;
+	 ::URI tmpuri{I->URI};
+	 tmpuri.Path = DeQuoteString(tmpuri.Path);
+	 if (URI == std::string(tmpuri))
+	    return I;
+      }
+   }
+   return nullptr;
+}
+									/*}}}*/
+// Queue::ItemDone - Item has been completed				/*{{{*/
+// ---------------------------------------------------------------------
+/* The worker signals this which causes the item to be removed from the
+   queue. If this is the last queue instance then it is removed from the
+   main queue too.*/
+bool pkgAcquire::Queue::ItemDone(QItem *Itm)
+{
+   PipeDepth--;
+   for (QItem::owner_iterator O = Itm->Owners.begin(); O != Itm->Owners.end(); ++O)
+   {
+      if ((*O)->Status == pkgAcquire::Item::StatFetching)
+	 (*O)->Status = pkgAcquire::Item::StatDone;
+   }
+
+   if (Itm->Owner->QueueCounter <= 1)
+      Owner->Dequeue(Itm->Owner);
+   else
+   {
+      Dequeue(Itm->Owner);
+      Owner->Bump();
+   }
+
+   return Cycle();
+}
+									/*}}}*/
+// Queue::Cycle - Queue new items into the method			/*{{{*/
+// ---------------------------------------------------------------------
+/* This locates a new idle item and sends it to the worker. If pipelining
+   is enabled then it keeps the pipe full. */
+bool pkgAcquire::Queue::Cycle()
+{
+   if (Items == 0 || Workers == 0)
+      return true;
+
+   if (PipeDepth < 0)
+      return _error->Error("Pipedepth failure");
+
+   // Look for a queable item
+   QItem *I = Items;
+   int ActivePriority = 0;
+   auto currentTime = clock::now();
+   while (PipeDepth < static_cast<decltype(PipeDepth)>(MaxPipeDepth))
+   {
+      for (; I != 0; I = I->Next) {
+	 if (I->Owner->Status == pkgAcquire::Item::StatFetching)
+	    ActivePriority = std::max(ActivePriority, I->GetPriority());
+	 if (I->Owner->Status == pkgAcquire::Item::StatIdle)
+	    break;
+      }
+
+      // Nothing to do, queue is idle.
+      if (I == 0)
+	 return true;
+
+      // This item has a lower priority than stuff in the pipeline, pretend
+      // the queue is idle
+      if (I->GetPriority() < ActivePriority)
+	 return true;
+
+      // Item is not ready yet, delay
+      if (I->GetFetchAfter() > currentTime)
+	 return true;
+
+      I->Worker = Workers;
+      for (auto const &O: I->Owners)
+	 O->Status = pkgAcquire::Item::StatFetching;
+      PipeDepth++;
+      if (Workers->QueueItem(I) == false)
+	 return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// Queue::Bump - Fetch any pending objects if we are idle		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called when an item in multiple queues is dequeued */
+void pkgAcquire::Queue::Bump()
+{
+   Cycle();
+}
+									/*}}}*/
+HashStringList pkgAcquire::Queue::QItem::GetExpectedHashes() const	/*{{{*/
+{
+   /* each Item can have multiple owners and each owner might have different
+      hashes, even if that is unlikely in practice and if so at least some
+      owners will later fail. There is one situation through which is not a
+      failure and still needs this handling: Two owners who expect the same
+      file, but one owner only knows the SHA1 while the other only knows SHA256. */
+   HashStringList superhsl;
+   for (pkgAcquire::Queue::QItem::owner_iterator O = Owners.begin(); O != Owners.end(); ++O)
+   {
+      HashStringList const hsl = (*O)->GetExpectedHashes();
+      // we merge both lists - if we find disagreement send no hashes
+      HashStringList::const_iterator hs = hsl.begin();
+      for (; hs != hsl.end(); ++hs)
+	 if (superhsl.push_back(*hs) == false)
+	    break;
+      if (hs != hsl.end())
+      {
+	 superhsl.clear();
+	 break;
+      }
+   }
+   return superhsl;
+}
+									/*}}}*/
+APT_PURE unsigned long long pkgAcquire::Queue::QItem::GetMaximumSize() const	/*{{{*/
+{
+   unsigned long long Maximum = std::numeric_limits<unsigned long long>::max();
+   for (auto const &O: Owners)
+   {
+      if (O->FileSize == 0)
+	 continue;
+      Maximum = std::min(Maximum, O->FileSize);
+   }
+   if (Maximum == std::numeric_limits<unsigned long long>::max())
+      return 0;
+   return Maximum;
+}
+									/*}}}*/
+APT_PURE int pkgAcquire::Queue::QItem::GetPriority() const		/*{{{*/
+{
+   int Priority = 0;
+   for (auto const &O: Owners)
+      Priority = std::max(Priority, O->Priority());
+
+   return Priority;
+}
+									/*}}}*/
+APT_PURE pkgAcquire::time_point pkgAcquire::Queue::QItem::GetFetchAfter() const /*{{{*/
+{
+   time_point FetchAfter{};
+   for (auto const &O : Owners)
+      FetchAfter = std::max(FetchAfter, O->FetchAfter());
+
+   return FetchAfter;
+}
+									/*}}}*/
+void pkgAcquire::Queue::QItem::SyncDestinationFiles() const		/*{{{*/
+{
+   /* ensure that the first owner has the best partial file of all and
+      the rest have (potentially dangling) symlinks to it so that
+      everything (like progress reporting) finds it easily */
+   std::string superfile = Owner->DestFile;
+   off_t supersize = 0;
+   for (pkgAcquire::Queue::QItem::owner_iterator O = Owners.begin(); O != Owners.end(); ++O)
+   {
+      if ((*O)->DestFile == superfile)
+	 continue;
+      struct stat file;
+      if (lstat((*O)->DestFile.c_str(),&file) == 0)
+      {
+	 if ((file.st_mode & S_IFREG) == 0)
+	    RemoveFile("SyncDestinationFiles", (*O)->DestFile);
+	 else if (supersize < file.st_size)
+	 {
+	    supersize = file.st_size;
+	    RemoveFile("SyncDestinationFiles", superfile);
+	    rename((*O)->DestFile.c_str(), superfile.c_str());
+	 }
+	 else
+	    RemoveFile("SyncDestinationFiles", (*O)->DestFile);
+	 if (symlink(superfile.c_str(), (*O)->DestFile.c_str()) != 0)
+	 {
+	    ; // not a problem per-se and no real alternative
+	 }
+      }
+   }
+}
+									/*}}}*/
+std::string pkgAcquire::Queue::QItem::Custom600Headers() const		/*{{{*/
+{
+   /* The others are relatively easy to merge, but this one?
+      Lets not merge and see how far we can run with it…
+      Likely, nobody will ever notice as all the items will
+      be of the same class and hence generate the same headers. */
+   return Owner->Custom600Headers();
+}
+									/*}}}*/
+
+// AcquireStatus::pkgAcquireStatus - Constructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgAcquireStatus::pkgAcquireStatus() : d(NULL), Percent(-1), Update(true), MorePulses(false)
+{
+   Start();
+}
+									/*}}}*/
+// AcquireStatus::Pulse - Called periodically				/*{{{*/
+// ---------------------------------------------------------------------
+/* This computes some internal state variables for the derived classes to
+   use. It generates the current downloaded bytes and total bytes to download
+   as well as the current CPS estimate. */
+static struct timeval GetTimevalFromSteadyClock()
+{
+   return SteadyDurationToTimeVal(std::chrono::steady_clock::now().time_since_epoch());
+}
+bool pkgAcquireStatus::Pulse(pkgAcquire *Owner)
+{
+   TotalBytes = 0;
+   CurrentBytes = 0;
+   TotalItems = 0;
+   CurrentItems = 0;
+
+   // Compute the total number of bytes to fetch
+   unsigned int Unknown = 0;
+   unsigned int Count = 0;
+   bool ExpectAdditionalItems = false;
+   for (pkgAcquire::ItemCIterator I = Owner->ItemsBegin(); 
+        I != Owner->ItemsEnd();
+	++I, ++Count)
+   {
+      TotalItems++;
+      if ((*I)->Status == pkgAcquire::Item::StatDone)
+	 ++CurrentItems;
+
+      // do we expect to acquire more files than we know of yet?
+      if ((*I)->ExpectedAdditionalItems > 0)
+         ExpectAdditionalItems = true;
+
+      TotalBytes += (*I)->FileSize;
+      if ((*I)->Complete == true)
+	 CurrentBytes += (*I)->FileSize;
+      if ((*I)->FileSize == 0 && (*I)->Complete == false)
+	 ++Unknown;
+   }
+
+   // Compute the current completion
+   unsigned long long ResumeSize = 0;
+   for (pkgAcquire::Worker *I = Owner->WorkersBegin(); I != 0;
+	I = Owner->WorkerStep(I))
+   {
+      if (I->CurrentItem != 0 && I->CurrentItem->Owner->Complete == false)
+      {
+	 CurrentBytes += I->CurrentItem->CurrentSize;
+	 ResumeSize += I->CurrentItem->ResumePoint;
+
+	 // Files with unknown size always have 100% completion
+	 if (I->CurrentItem->Owner->FileSize == 0 &&
+	     I->CurrentItem->Owner->Complete == false)
+	    TotalBytes += I->CurrentItem->CurrentSize;
+      }
+   }
+   
+   // Normalize the figures and account for unknown size downloads
+   if (TotalBytes <= 0)
+      TotalBytes = 1;
+   if (Unknown == Count)
+      TotalBytes = Unknown;
+
+   // Wha?! Is not supposed to happen.
+   if (CurrentBytes > TotalBytes)
+      CurrentBytes = TotalBytes;
+
+   // Compute the CPS
+   struct timeval NewTime = GetTimevalFromSteadyClock();
+
+   if ((NewTime.tv_sec - Time.tv_sec == 6 && NewTime.tv_usec > Time.tv_usec) ||
+       NewTime.tv_sec - Time.tv_sec > 6)
+   {
+      std::chrono::duration<double> Delta =
+	 std::chrono::seconds(NewTime.tv_sec - Time.tv_sec) +
+	 std::chrono::microseconds(NewTime.tv_usec - Time.tv_usec);
+
+      // Compute the CPS value
+      if (Delta < std::chrono::milliseconds(10))
+	 CurrentCPS = 0;
+      else
+	 CurrentCPS = ((CurrentBytes - ResumeSize) - LastBytes)/ Delta.count();
+      LastBytes = CurrentBytes - ResumeSize;
+      ElapsedTime = llround(Delta.count());
+      Time = NewTime;
+   }
+
+   double const OldPercent = Percent;
+   // calculate the percentage, if we have too little data assume 1%
+   if (ExpectAdditionalItems)
+      Percent = 0;
+   else
+      // use both files and bytes because bytes can be unreliable
+      Percent = (0.8 * (CurrentBytes/double(TotalBytes)*100.0) +
+                 0.2 * (CurrentItems/double(TotalItems)*100.0));
+
+   // debug
+   if (_config->FindB("Debug::acquire::progress", false) == true)
+   {
+      std::clog
+         << "["
+         << std::setw(5) << std::setprecision(4) << std::showpoint << Percent 
+         << "]"
+         << " Bytes: "
+         << SizeToStr(CurrentBytes) << " / " << SizeToStr(TotalBytes)
+         << " # Files: "
+         << CurrentItems << " / " << TotalItems
+         << std::endl;
+   }
+
+   double const DiffPercent = Percent - OldPercent;
+   if (DiffPercent < 0.001 && _config->FindB("Acquire::Progress::Diffpercent", false) == true)
+      return true;
+
+   int fd = _config->FindI("APT::Status-Fd",-1);
+   if(fd > 0)
+   {
+      unsigned long long ETA = 0;
+      if(CurrentCPS > 0 && TotalBytes > CurrentBytes)
+         ETA = (TotalBytes - CurrentBytes) / CurrentCPS;
+
+      std::string msg;
+      long i = CurrentItems < TotalItems ? CurrentItems + 1 : CurrentItems;
+      // only show the ETA if it makes sense
+      auto const twodays = std::chrono::seconds(std::chrono::hours(24 * 2)).count();
+      if (ETA > 0 && ETA < static_cast<decltype(ETA)>(twodays))
+	 strprintf(msg, _("Retrieving file %li of %li (%s remaining)"), i, TotalItems, TimeToStr(ETA).c_str());
+      else
+	 strprintf(msg, _("Retrieving file %li of %li"), i, TotalItems);
+
+      // build the status str
+      std::ostringstream str;
+      str.imbue(std::locale::classic());
+      str.precision(4);
+      str << "dlstatus" << ':' << std::fixed << i << ':' << Percent << ':' << msg << '\n';
+      auto const dlstatus = str.str();
+      FileFd::Write(fd, dlstatus.data(), dlstatus.size());
+   }
+
+   return true;
+}
+									/*}}}*/
+// AcquireStatus::Start - Called when the download is started		/*{{{*/
+// ---------------------------------------------------------------------
+/* We just reset the counters */
+void pkgAcquireStatus::Start()
+{
+   Time = StartTime = GetTimevalFromSteadyClock();
+   LastBytes = 0;
+   CurrentCPS = 0;
+   CurrentBytes = 0;
+   TotalBytes = 0;
+   FetchedBytes = 0;
+   ElapsedTime = 0;
+   TotalItems = 0;
+   CurrentItems = 0;
+}
+									/*}}}*/
+// AcquireStatus::Stop - Finished downloading				/*{{{*/
+// ---------------------------------------------------------------------
+/* This accurately computes the elapsed time and the total overall CPS. */
+void pkgAcquireStatus::Stop()
+{
+   // Compute the CPS and elapsed time
+   struct timeval NewTime = GetTimevalFromSteadyClock();
+
+   std::chrono::duration<double> Delta =
+      std::chrono::seconds(NewTime.tv_sec - StartTime.tv_sec) +
+      std::chrono::microseconds(NewTime.tv_usec - StartTime.tv_usec);
+
+   // Compute the CPS value
+   if (Delta < std::chrono::milliseconds(10))
+      CurrentCPS = 0;
+   else
+      CurrentCPS = FetchedBytes / Delta.count();
+   LastBytes = CurrentBytes;
+   ElapsedTime = llround(Delta.count());
+}
+									/*}}}*/
+// AcquireStatus::Fetched - Called when a byte set has been fetched	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to get accurate final transfer rate reporting. */
+void pkgAcquireStatus::Fetched(unsigned long long Size,unsigned long long Resume)
+{
+   FetchedBytes += Size - Resume;
+}
+									/*}}}*/
+bool pkgAcquireStatus::ReleaseInfoChanges(metaIndex const * const LastRelease, metaIndex const * const CurrentRelease, std::vector<ReleaseInfoChange> &&Changes)/*{{{*/
+{
+   (void) LastRelease;
+   (void) CurrentRelease;
+   return ReleaseInfoChangesAsGlobalErrors(std::move(Changes));
+}
+									/*}}}*/
+bool pkgAcquireStatus::ReleaseInfoChangesAsGlobalErrors(std::vector<ReleaseInfoChange> &&Changes)/*{{{*/
+{
+   bool AllOkay = true;
+   for (auto const &c: Changes)
+      if (c.DefaultAction)
+	 _error->Notice("%s", c.Message.c_str());
+      else
+      {
+	 _error->Error("%s", c.Message.c_str());
+	 AllOkay = false;
+      }
+   return AllOkay;
+}
+									/*}}}*/
+
+
+pkgAcquire::UriIterator::UriIterator(pkgAcquire::Queue *Q) : d(NULL), CurQ(Q), CurItem(0)
+{
+   while (CurItem == 0 && CurQ != 0)
+   {
+      CurItem = CurQ->Items;
+      CurQ = CurQ->Next;
+   }
+}
+
+pkgAcquire::UriIterator::~UriIterator() {}
+pkgAcquire::MethodConfig::~MethodConfig() { delete d; }
+pkgAcquireStatus::~pkgAcquireStatus() {}
diff --git a/apt-pkg/acquire.h b/apt-pkg/acquire.h
new file mode 100644
index 0000000..17b6876
--- /dev/null
+++ b/apt-pkg/acquire.h
@@ -0,0 +1,874 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Acquire - File Acquiration
+   
+   This module contains the Acquire system. It is responsible for bringing
+   files into the local pathname space. It deals with URIs for files and
+   URI handlers responsible for downloading or finding the URIs.
+   
+   Each file to download is represented by an Acquire::Item class subclassed
+   into a specialization. The Item class can add itself to several URI
+   acquire queues each prioritized by the download scheduler. When the
+   system is run the proper URI handlers are spawned and the acquire
+   queues are fed into the handlers by the schedular until the queues are
+   empty. This allows for an Item to be downloaded from an alternate source
+   if the first try turns out to fail. It also allows concurrent downloading
+   of multiple items from multiple sources as well as dynamic balancing
+   of load between the sources.
+   
+   Scheduling of downloads is done on a first ask first get basis. This
+   preserves the order of the download as much as possible. And means the
+   fastest source will tend to process the largest number of files.
+   
+   Internal methods and queues for performing gzip decompression,
+   md5sum hashing and file copying are provided to allow items to apply
+   a number of transformations to the data files they are working with.
+   
+   ##################################################################### */
+									/*}}}*/
+
+/** \defgroup acquire Acquire system					{{{
+ *
+ *  \brief The Acquire system is responsible for retrieving files from
+ *  local or remote URIs and postprocessing them (for instance,
+ *  verifying their authenticity).  The core class in this system is
+ *  pkgAcquire, which is responsible for managing the download queues
+ *  during the download.  There is at least one download queue for
+ *  each supported protocol; protocols such as http may provide one
+ *  queue per host.
+ *
+ *  Each file to download is represented by a subclass of
+ *  pkgAcquire::Item.  The files add themselves to the download
+ *  queue(s) by providing their URI information to
+ *  pkgAcquire::Item::QueueURI, which calls pkgAcquire::Enqueue.
+ *
+ *  Once the system is set up, the Run method will spawn subprocesses
+ *  to handle the enqueued URIs; the scheduler will then take items
+ *  from the queues and feed them into the handlers until the queues
+ *  are empty.
+ *
+ *  \todo Acquire supports inserting an object into several queues at
+ *  once, but it is not clear what its behavior in this case is, and
+ *  no subclass of pkgAcquire::Item seems to actually use this
+ *  capability.
+ */									/*}}}*/
+
+/** \addtogroup acquire
+ *
+ *  @{
+ *
+ *  \file acquire.h
+ */
+
+#ifndef PKGLIB_ACQUIRE_H
+#define PKGLIB_ACQUIRE_H
+
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/weakptr.h>
+
+#include <chrono>
+#include <string>
+#include <vector>
+
+#include <stddef.h>
+#include <sys/select.h>
+#include <sys/time.h>
+
+
+
+class pkgAcquireStatus;
+class metaIndex;
+
+/** \brief The core download scheduler.					{{{
+ *
+ *  This class represents an ongoing download.  It manages the lists
+ *  of active and pending downloads and handles setting up and tearing
+ *  down download-related structures.
+ *
+ *  \todo Why all the protected data items and methods?
+ */
+class APT_PUBLIC pkgAcquire
+{   
+   private:
+   /** \brief The monotonic clock used by the Acquire system */
+   using clock = std::chrono::steady_clock;
+   /** \brief Time point on our monotonic clock */
+   using time_point = std::chrono::time_point<clock>;
+   /** \brief FD of the Lock file we acquire in Setup (if any) */
+   int LockFD;
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   public:
+   
+   class Item;
+   class Queue;
+   class Worker;
+   struct MethodConfig;
+   struct ItemDesc;
+   friend class Item;
+   friend class pkgAcqMetaBase;
+   friend class Queue;
+
+   typedef std::vector<Item *>::iterator ItemIterator;
+   typedef std::vector<Item *>::const_iterator ItemCIterator;
+
+   protected:
+   
+   /** \brief A list of items to download.
+    *
+    *  This is built monotonically as items are created and only
+    *  emptied when the download shuts down.
+    */
+   std::vector<Item *> Items;
+   
+   /** \brief The head of the list of active queues.
+    *
+    *  \todo why a hand-managed list of queues instead of std::list or
+    *  std::set?
+    */
+   Queue *Queues;
+
+   /** \brief The head of the list of active workers.
+    *
+    *  \todo why a hand-managed list of workers instead of std::list
+    *  or std::set?
+    */
+   Worker *Workers;
+
+   /** \brief The head of the list of acquire method configurations.
+    *
+    *  Each protocol (http, ftp, gzip, etc) via which files can be
+    *  fetched can have a representation in this list.  The
+    *  configuration data is filled in by parsing the 100 Capabilities
+    *  string output by a method on startup (see
+    *  pkgAcqMethod::pkgAcqMethod and pkgAcquire::GetConfig).
+    *
+    *  \todo why a hand-managed config dictionary instead of std::map?
+    */
+   MethodConfig *Configs;
+
+   /** \brief The progress indicator for this download. */
+   pkgAcquireStatus *Log;
+
+   /** \brief The number of files which are to be fetched. */
+   unsigned long ToFetch;
+
+   // Configurable parameters for the scheduler
+
+   /** \brief Represents the queuing strategy for remote URIs. */
+   enum QueueStrategy {
+     /** \brief Generate one queue for each protocol/host combination; downloads from 
+      *  multiple hosts can proceed in parallel.
+      */
+     QueueHost,
+     /** \brief Generate a single queue for each protocol; serialize
+      *  downloads from multiple hosts.
+      */
+     QueueAccess} QueueMode;
+
+   /** \brief If \b true, debugging information will be dumped to std::clog. */
+   bool const Debug;
+   /** \brief If \b true, a download is currently in progress. */
+   bool Running;
+
+   /** \brief Add the given item to the list of items. */
+   void Add(Item *Item);
+
+   /** \brief Remove the given item from the list of items. */
+   void Remove(Item *Item);
+
+   /** \brief Add the given worker to the list of workers. */
+   void Add(Worker *Work);
+
+   /** \brief Remove the given worker from the list of workers. */
+   void Remove(Worker *Work);
+   
+   /** \brief Insert the given fetch request into the appropriate queue.
+    *
+    *  \param Item The URI to download and the item to download it
+    *  for.  Copied by value into the queue; no reference to Item is
+    *  retained.
+    */
+   void Enqueue(ItemDesc &Item);
+
+   /** \brief Remove all fetch requests for this item from all queues. */
+   void Dequeue(Item *Item);
+
+   /** \brief Determine the fetch method and queue of a URI.
+    *
+    *  \param URI The URI to fetch.
+    *
+    *  \param[out] Config A location in which to place the method via
+    *  which the URI is to be fetched.
+    *
+    *  \return the string-name of the queue in which a fetch request
+    *  for the given URI should be placed.
+    */
+   std::string QueueName(std::string URI,MethodConfig const *&Config);
+
+   /** \brief Build up the set of file descriptors upon which select() should
+    *  block.
+    *
+    *  The default implementation inserts the file descriptors
+    *  corresponding to active downloads.
+    *
+    *  \param[out] Fd The largest file descriptor in the generated sets.
+    *
+    *  \param[out] RSet The set of file descriptors that should be
+    *  watched for input.
+    *
+    *  \param[out] WSet The set of file descriptors that should be
+    *  watched for output.
+    */
+   virtual void SetFds(int &Fd,fd_set *RSet,fd_set *WSet);
+
+   /** Handle input from and output to file descriptors which select()
+    *  has determined are ready.  The default implementation
+    *  dispatches to all active downloads.
+    *
+    *  \param RSet The set of file descriptors that are ready for
+    *  input.
+    *
+    *  \param WSet The set of file descriptors that are ready for
+    *  output.
+    *
+    * \return false if there is an error condition on one of the fds
+    */
+   virtual bool RunFds(fd_set *RSet,fd_set *WSet);
+
+   /** \brief Check for idle queues with ready-to-fetch items.
+    *
+    *  Called by pkgAcquire::Queue::Done each time an item is dequeued
+    *  but remains on some queues; i.e., another queue should start
+    *  fetching it.
+    */
+   void Bump();
+   
+   public:
+
+   /** \brief Retrieve information about a fetch method by name.
+    *
+    *  \param Access The name of the method to look up.
+    *
+    *  \return the method whose name is Access, or \b NULL if no such method exists.
+    */
+   MethodConfig *GetConfig(std::string Access);
+
+   /** \brief Provides information on how a download terminated. */
+   enum RunResult {
+     /** \brief All files were fetched successfully. */
+     Continue,
+
+     /** \brief Some files failed to download. */
+     Failed,
+
+     /** \brief The download was cancelled by the user (i.e., #Log's
+      *  pkgAcquireStatus::Pulse() method returned \b false).
+      */
+     Cancelled};
+
+   /** \brief Download all the items that have been Add()ed to this
+    *  download process.
+    *
+    *  This method will block until the download completes, invoking
+    *  methods on #Log to report on the progress of the download.
+    *
+    *  \param PulseInterval The method pkgAcquireStatus::Pulse will be
+    *  invoked on #Log at intervals of PulseInterval milliseconds.
+    *
+    *  \return the result of the download.
+    */
+   RunResult Run(int PulseInterval=500000);
+
+   /** \brief Remove all items from this download process, terminate
+    *  all download workers, and empty all queues.
+    */
+   void Shutdown();
+   
+   /** \brief Get the first Worker object.
+    *
+    *  \return the first active worker in this download process.
+    */
+   inline Worker *WorkersBegin() {return Workers;};
+
+   /** \brief Advance to the next Worker object.
+    *
+    *  \return the worker immediately following I, or \b NULL if none
+    *  exists.
+    */
+   Worker *WorkerStep(Worker *I) APT_PURE;
+
+   /** \brief Get the head of the list of items. */
+   inline ItemIterator ItemsBegin() {return Items.begin();};
+   inline ItemCIterator ItemsBegin() const {return Items.begin();};
+
+   /** \brief Get the end iterator of the list of items. */
+   inline ItemIterator ItemsEnd() {return Items.end();};
+   inline ItemCIterator ItemsEnd() const {return Items.end();};
+   
+   // Iterate over queued Item URIs
+   class UriIterator;
+   /** \brief Get the head of the list of enqueued item URIs.
+    *
+    *  This iterator will step over every element of every active
+    *  queue.
+    */
+   UriIterator UriBegin();
+   /** \brief Get the end iterator of the list of enqueued item URIs. */
+   UriIterator UriEnd();
+   
+   /** Deletes each entry in the given directory that is not being
+    *  downloaded by this object.  For instance, when downloading new
+    *  list files, calling Clean() will delete the old ones.
+    *
+    *  \param Dir The directory to be cleaned out.
+    *
+    *  \return \b true if the directory exists and is readable.
+    */
+   bool Clean(std::string Dir);
+
+   /** \return the total size in bytes of all the items included in
+    *  this download.
+    */
+   unsigned long long TotalNeeded();
+
+   /** \return the size in bytes of all non-local items included in
+    *  this download.
+    */
+   unsigned long long FetchNeeded();
+
+   /** \return the amount of data to be fetched that is already
+    *  present on the filesystem.
+    */
+   unsigned long long PartialPresent();
+
+   void SetLog(pkgAcquireStatus *Progress) { Log = Progress; }
+
+   /** \brief acquire lock and perform directory setup
+    *
+    *  \param Lock defines a lock file that should be acquired to ensure
+    *  only one Acquire class is in action at the time or an empty string
+    *  if no lock file should be used. If set also all needed directories
+    *  will be created and setup.
+    */
+   bool GetLock(std::string const &Lock);
+
+   /** \brief Construct a new pkgAcquire. */
+   explicit pkgAcquire(pkgAcquireStatus *Log);
+   pkgAcquire();
+
+   /** \brief Destroy this pkgAcquire object.
+    *
+    *  Destroys all queue, method, and item objects associated with
+    *  this download.
+    */
+   virtual ~pkgAcquire();
+
+   APT_HIDDEN static std::string URIEncode(std::string const &part);
+
+   private:
+   APT_HIDDEN void Initialize();
+};
+
+/** \brief Represents a single download source from which an item
+ *  should be downloaded.
+ *
+ *  An item may have several associated ItemDescs over its lifetime.
+ */
+struct APT_PUBLIC pkgAcquire::ItemDesc : public WeakPointable
+{
+   /** \brief URI from which to download this item. */
+   std::string URI;
+   /** \brief description of this item. */
+   std::string Description;
+   /** \brief shorter description of this item. */
+   std::string ShortDesc;
+   /** \brief underlying item which is to be downloaded. */
+   Item *Owner;
+};
+									/*}}}*/
+/** \brief A single download queue in a pkgAcquire object.		{{{
+ *
+ *  \todo Why so many protected values?
+ */
+class APT_PUBLIC pkgAcquire::Queue
+{
+   friend class pkgAcquire;
+   friend class pkgAcquire::UriIterator;
+   friend class pkgAcquire::Worker;
+
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   /** \brief The next queue in the pkgAcquire object's list of queues. */
+   Queue *Next;
+   
+   protected:
+
+   /** \brief A single item placed in this queue. */
+   struct QItem : public ItemDesc
+   {
+      /** \brief The next item in the queue. */
+      QItem *Next;
+      /** \brief The worker associated with this item, if any. */
+      pkgAcquire::Worker *Worker;
+
+      /** \brief The underlying items interested in the download */
+      std::vector<Item*> Owners;
+
+      /** \brief How many bytes of the file have been downloaded.  Zero
+       *  if the current progress of the file cannot be determined.
+       */
+      unsigned long long CurrentSize = 0;
+
+      /** \brief The total number of bytes to be downloaded.  Zero if the
+       *  total size of the final is unknown.
+       */
+      unsigned long long TotalSize = 0;
+
+      /** \brief How much of the file was already downloaded prior to
+       *  starting this worker.
+       */
+      unsigned long long ResumePoint = 0;
+
+      typedef std::vector<Item*>::const_iterator owner_iterator;
+
+      /** \brief Assign the ItemDesc portion of this QItem from
+       *  another ItemDesc
+       */
+      void operator =(pkgAcquire::ItemDesc const &I)
+      {
+	 URI = I.URI;
+	 Description = I.Description;
+	 ShortDesc = I.ShortDesc;
+	 Owners.clear();
+	 Owners.push_back(I.Owner);
+	 Owner = I.Owner;
+      };
+
+      /** @return the sum of all expected hashes by all owners */
+      HashStringList GetExpectedHashes() const;
+
+      /** @return smallest maximum size of all owners */
+      unsigned long long GetMaximumSize() const;
+
+      /** \brief get partial files in order */
+      void SyncDestinationFiles() const;
+
+      /** @return the custom headers to use for this item */
+      std::string Custom600Headers() const;
+      /** @return the maximum priority of this item */
+      int APT_HIDDEN GetPriority() const;
+      /** @return the maximum time to fetch this item at */
+      time_point APT_HIDDEN GetFetchAfter() const;
+   };
+
+   /** \brief The name of this queue. */
+   std::string Name;
+
+   /** \brief The head of the list of items contained in this queue.
+    *
+    *  \todo why a by-hand list instead of an STL structure?
+    */
+   QItem *Items;
+
+   /** \brief The head of the list of workers associated with this queue.
+    *
+    *  \todo This is plural because support exists in Queue for
+    *  multiple workers.  However, it does not appear that there is
+    *  any way to actually associate more than one worker with a
+    *  queue.
+    *
+    *  \todo Why not just use a std::set?
+    */
+   pkgAcquire::Worker *Workers;
+
+   /** \brief the download scheduler with which this queue is associated. */
+   pkgAcquire *Owner;
+
+   /** \brief The number of entries in this queue that are currently
+    *  being downloaded.
+    */
+   signed long PipeDepth;
+
+   /** \brief The maximum number of entries that this queue will
+    *  attempt to download at once.
+    */
+   unsigned long MaxPipeDepth;
+   
+   public:
+   
+   /** \brief Insert the given fetch request into this queue. 
+    *
+    *  \return \b true if the queuing was successful. May return
+    *  \b false if the Item is already in the queue
+    */
+   bool Enqueue(ItemDesc &Item);
+
+   /** \brief Remove all fetch requests for the given item from this queue.
+    *
+    *  \return \b true if at least one request was removed from the queue.
+    */
+   bool Dequeue(Item *Owner);
+
+   /** \brief Locate an item in this queue.
+    *
+    *  \param URI A URI to match against.
+    *  \param Owner A pkgAcquire::Worker to match against.
+    *
+    *  \return the first item in the queue whose URI is #URI and that
+    *  is being downloaded by #Owner.
+    */
+   QItem *FindItem(std::string URI,pkgAcquire::Worker *Owner) APT_PURE;
+
+   /** Presumably this should start downloading an item?
+    *
+    *  \todo Unimplemented.  Implement it or remove?
+    */
+   bool ItemStart(QItem *Itm,unsigned long long Size);
+
+   /** \brief Remove the given item from this queue and set its state
+    *  to pkgAcquire::Item::StatDone.
+    *
+    *  If this is the only queue containing the item, the item is also
+    *  removed from the main queue by calling pkgAcquire::Dequeue.
+    *
+    *  \param Itm The item to remove.
+    *
+    *  \return \b true if no errors are encountered.
+    */
+   bool ItemDone(QItem *Itm);
+   
+   /** \brief Start the worker process associated with this queue.
+    *
+    *  If a worker process is already associated with this queue,
+    *  this is equivalent to calling Cycle().
+    *
+    *  \return \b true if the startup was successful.
+    */
+   bool Startup();
+
+   /** \brief Shut down the worker process associated with this queue.
+    *
+    *  \param Final If \b true, then the process is stopped unconditionally.
+    *               Otherwise, it is only stopped if it does not need cleanup
+    *               as indicated by the pkgAcqMethod::NeedsCleanup member of
+    *               its configuration.
+    *
+    *  \return \b true.
+    */
+   bool Shutdown(bool Final);
+
+   /** \brief Send idle items to the worker process.
+    *
+    *  Fills up the pipeline by inserting idle items into the worker's queue.
+    */
+   bool Cycle();
+
+   /** \brief Check for items that could be enqueued.
+    *
+    *  Call this after an item placed in multiple queues has gone from
+    *  the pkgAcquire::Item::StatFetching state to the
+    *  pkgAcquire::Item::StatIdle state, to possibly refill an empty queue.
+    *  This is an alias for Cycle().
+    *
+    *  \todo Why both this and Cycle()?  Are they expected to be
+    *  different someday?
+    */
+   void Bump();
+   
+   /** \brief Create a new Queue.
+    *
+    *  \param Name The name of the new queue.
+    *  \param Owner The download process that owns the new queue.
+    */
+   Queue(std::string const &Name,pkgAcquire * const Owner);
+
+   /** Shut down all the worker processes associated with this queue
+    *  and empty the queue.
+    */
+   virtual ~Queue();
+};
+									/*}}}*/
+/** \brief Iterates over all the URIs being fetched by a pkgAcquire object.	{{{*/
+class APT_PUBLIC pkgAcquire::UriIterator
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   /** The next queue to iterate over. */
+   pkgAcquire::Queue *CurQ;
+   /** The item that we currently point at. */
+   pkgAcquire::Queue::QItem *CurItem;
+   
+   public:
+   
+   inline void operator ++() {operator ++(0);};
+
+   void operator ++(int)
+   {
+      CurItem = CurItem->Next;
+      while (CurItem == 0 && CurQ != 0)
+      {
+	 CurItem = CurQ->Items;
+	 CurQ = CurQ->Next;
+      }
+   };
+   
+   inline pkgAcquire::Queue::QItem const *operator ->() const {return CurItem;};
+   inline bool operator !=(UriIterator const &rhs) const {return rhs.CurQ != CurQ || rhs.CurItem != CurItem;};
+   inline bool operator ==(UriIterator const &rhs) const {return rhs.CurQ == CurQ && rhs.CurItem == CurItem;};
+   
+   /** \brief Create a new UriIterator.
+    *
+    *  \param Q The queue over which this UriIterator should iterate.
+    */
+   explicit UriIterator(pkgAcquire::Queue *Q);
+   virtual ~UriIterator();
+};
+									/*}}}*/
+/** \brief Information about the properties of a single acquire method.	{{{*/
+struct APT_PUBLIC pkgAcquire::MethodConfig
+{
+   class Private;
+   /** \brief dpointer placeholder (for later in case we need it) */
+   Private *const d;
+
+   /** \brief The next link on the acquire method list.
+    *
+    *  \todo Why not an STL container?
+    */
+   MethodConfig *Next;
+   
+   /** \brief The name of this acquire method (e.g., http). */
+   std::string Access;
+
+   /** \brief The implementation version of this acquire method. */
+   std::string Version;
+
+   /** \brief If \b true, only one download queue should be created for this
+    *  method.
+    */
+   bool SingleInstance;
+
+   /** \brief If \b true, this method supports pipelined downloading. */
+   bool Pipeline;
+
+   /** \brief If \b true, the worker process should send the entire
+    *  APT configuration tree to the fetch subprocess when it starts
+    *  up.
+    */
+   bool SendConfig;
+
+   /** \brief If \b true, this fetch method does not require network access;
+    *  all files are to be acquired from the local disk.
+    */
+   bool LocalOnly;
+
+   /** \brief If \b true, the subprocess has to carry out some cleanup
+    *  actions before shutting down.
+    *
+    *  For instance, the cdrom method needs to unmount the CD after it
+    *  finishes.
+    */
+   bool NeedsCleanup;
+
+   /** \brief If \b true, this fetch method acquires files from removable media. */
+   bool Removable;
+   
+   /** \brief Set up the default method parameters.
+    *
+    *  All fields are initialized to NULL, "", or \b false as
+    *  appropriate.
+    */
+   MethodConfig();
+
+   APT_HIDDEN bool GetAuxRequests() const;
+   APT_HIDDEN void SetAuxRequests(bool const value);
+   APT_HIDDEN bool GetSendURIEncoded() const;
+   APT_HIDDEN void SetSendURIEncoded(bool const value);
+
+   virtual ~MethodConfig();
+};
+									/*}}}*/
+/** \brief A monitor object for downloads controlled by the pkgAcquire class.	{{{
+ *
+ *  \todo Why protected members?
+ */
+class APT_PUBLIC pkgAcquireStatus
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   protected:
+   
+   /** \brief The last time at which this monitor object was updated. */
+   struct timeval Time;
+
+   /** \brief The time at which the download started. */
+   struct timeval StartTime;
+
+   /** \brief The number of bytes fetched as of the previous call to
+    *  pkgAcquireStatus::Pulse, including local items.
+    */
+   unsigned long long LastBytes;
+
+   /** \brief The current rate of download as of the most recent call
+    *  to pkgAcquireStatus::Pulse, in bytes per second.
+    */
+   unsigned long long CurrentCPS;
+
+   /** \brief The number of bytes fetched as of the most recent call
+    *  to pkgAcquireStatus::Pulse, including local items.
+    */
+   unsigned long long CurrentBytes;
+
+   /** \brief The total number of bytes that need to be fetched.
+    *
+    *  \warning This member is inaccurate, as new items might be
+    *  enqueued while the download is in progress!
+    */
+   unsigned long long TotalBytes;
+
+   /** \brief The total number of bytes accounted for by items that
+    *  were successfully fetched.
+    */
+   unsigned long long FetchedBytes;
+
+   /** \brief The amount of time that has elapsed since the download
+    *   started.
+    */
+   unsigned long long ElapsedTime;
+
+   /** \brief The total number of items that need to be fetched.
+    *
+    *  \warning This member is inaccurate, as new items might be
+    *  enqueued while the download is in progress!
+    */
+   unsigned long TotalItems;
+
+   /** \brief The number of items that have been successfully downloaded. */
+   unsigned long CurrentItems;
+   
+   /** \brief The estimated percentage of the download (0-100)
+    */
+   double Percent;
+
+   public:
+
+   /** \brief If \b true, the download scheduler should call Pulse()
+    *  at the next available opportunity.
+    */
+   bool Update;
+
+   /** \brief If \b true, extra Pulse() invocations will be performed.
+    *
+    *  With this option set, Pulse() will be called every time that a
+    *  download item starts downloading, finishes downloading, or
+    *  terminates with an error.
+    */
+   bool MorePulses;
+      
+   /** \brief Invoked when a local or remote file has been completely fetched.
+    *
+    *  \param Size The size of the file fetched.
+    *
+    *  \param ResumePoint How much of the file was already fetched.
+    */
+   virtual void Fetched(unsigned long long Size,unsigned long long ResumePoint);
+   
+   /** \brief Invoked when the user should be prompted to change the
+    *         inserted removable media.
+    *
+    *  This method should not return until the user has confirmed to
+    *  the user interface that the media change is complete.
+    *
+    *  \param Media The name of the media type that should be changed.
+    *
+    *  \param Drive The identifying name of the drive whose media
+    *               should be changed.
+    *
+    *  \return \b true if the user confirms the media change, \b
+    *  false if it is cancelled.
+    *
+    *  \todo This is a horrible blocking monster; it should be CPSed
+    *  with prejudice.
+    */
+   virtual bool MediaChange(std::string Media,std::string Drive) = 0;
+
+   struct ReleaseInfoChange
+   {
+      std::string Type; /*!< Type of the change like "Origin", "Codename", "Version", … */
+      std::string From; /*!< old value */
+      std::string To; /*!< new value */
+      std::string Message; /*!< translated message describing the change */
+      bool DefaultAction; /*!< true if the change is informational, false if it must be explicitly confirmed */
+   };
+   /** \brief ask the user for confirmation of changes to infos about a repository
+    *
+    *  This method should present the user with a choice of accepting the change
+    *  or not and indicate the user opinion via the return value. If DefaultAction is true
+    *  it is acceptable to only notify the user about the change, but to accept the change
+    *  automatically on behalf of the user.
+    *
+    *  The default implementation will fail if any Change has DefaultAction == false. Regardless of
+    *  success it will print for each change the message attached to it via GlobalError either as an
+    *  error (if DefaultAction == false) or as a notice otherwise.
+    *
+    *  @param LastRelease can be used to extract further information from the previous Release file
+    *  @param CurrentRelease can be used to extract further information from the current Release file
+    *  @param Changes is an array of changes alongside explanatory messages
+    *                 which should be presented in some way to the user.
+    *  @return \b true if all changes are accepted by user, otherwise or if user can't be asked \b false
+    */
+   virtual bool ReleaseInfoChanges(metaIndex const * const LastRelease, metaIndex const * const CurrentRelease, std::vector<ReleaseInfoChange> &&Changes);
+   APT_HIDDEN static bool ReleaseInfoChangesAsGlobalErrors(std::vector<ReleaseInfoChange> &&Changes);
+
+   /** \brief Invoked when an item is confirmed to be up-to-date.
+
+    * For instance, when an HTTP download is informed that the file on
+    * the server was not modified.
+    */
+   virtual void IMSHit(pkgAcquire::ItemDesc &/*Itm*/) {};
+
+   /** \brief Invoked when some of an item's data is fetched. */
+   virtual void Fetch(pkgAcquire::ItemDesc &/*Itm*/) {};
+
+   /** \brief Invoked when an item is successfully and completely fetched. */
+   virtual void Done(pkgAcquire::ItemDesc &/*Itm*/) {};
+
+   /** \brief Invoked when the process of fetching an item encounters
+    *  a fatal error.
+    */
+   virtual void Fail(pkgAcquire::ItemDesc &/*Itm*/) {};
+
+   /** \brief Periodically invoked while the Acquire process is underway.
+    *
+    *  Subclasses should first call pkgAcquireStatus::Pulse(), then
+    *  update their status output.  The download process is blocked
+    *  while Pulse() is being called.
+    *
+    *  \return \b false if the user asked to cancel the whole Acquire process.
+    *
+    *  \see pkgAcquire::Run
+    */
+   virtual bool Pulse(pkgAcquire *Owner);
+
+   /** \brief Invoked when the Acquire process starts running. */
+   virtual void Start();
+
+   /** \brief Invoked when the Acquire process stops running. */
+   virtual void Stop();
+   
+   /** \brief Initialize all counters to 0 and the time to the current time. */
+   pkgAcquireStatus();
+   virtual ~pkgAcquireStatus();
+};
+									/*}}}*/
+/** @} */
+
+#endif
diff --git a/apt-pkg/algorithms.cc b/apt-pkg/algorithms.cc
new file mode 100644
index 0000000..26d8c71
--- /dev/null
+++ b/apt-pkg/algorithms.cc
@@ -0,0 +1,1623 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Algorithms - A set of misc algorithms
+
+   The pkgProblemResolver class has become insanely complex and
+   very sophisticated, it handles every test case I have thrown at it
+   to my satisfaction. Understanding exactly why all the steps the class
+   does are required is difficult and changing though not very risky
+   may result in other cases not working.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/dpkgpm.h>
+#include <apt-pkg/edsp.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/version.h>
+
+#include <apt-pkg/prettyprinters.h>
+
+#include <cstdlib>
+#include <iostream>
+#include <map>
+#include <set>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+#include <string.h>
+#include <sys/utsname.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+class APT_HIDDEN pkgSimulatePrivate
+{
+public:
+   std::vector<pkgDPkgPM::Item> List;
+};
+// Simulate::Simulate - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* The legacy translations here of input Pkg iterators is obsolete, 
+   this is not necessary since the pkgCaches are fully shared now. */
+pkgSimulate::pkgSimulate(pkgDepCache *Cache) : pkgPackageManager(Cache),
+		            d(new pkgSimulatePrivate()), iPolicy(Cache),
+			    Sim(&Cache->GetCache(),&iPolicy),
+			    group(Sim)
+{
+   Sim.Init(0);
+   auto PackageCount = Cache->Head().PackageCount;
+   Flags = new unsigned char[PackageCount];
+   memset(Flags,0,sizeof(*Flags)*PackageCount);
+
+   // Fake a filename so as not to activate the media swapping
+   string Jnk = "SIMULATE";
+   for (decltype(PackageCount) I = 0; I != PackageCount; ++I)
+      FileNames[I] = Jnk;
+
+   Cache->CheckConsistency("simulate");
+}
+									/*}}}*/
+// Simulate::~Simulate - Destructor					/*{{{*/
+pkgSimulate::~pkgSimulate()
+{
+   delete[] Flags;
+   delete d;
+}
+									/*}}}*/
+// Simulate::Describe - Describe a package				/*{{{*/
+// ---------------------------------------------------------------------
+/* Parameter Current == true displays the current package version,
+   Parameter Candidate == true displays the candidate package version */
+void pkgSimulate::Describe(PkgIterator Pkg,ostream &out,bool Current,bool Candidate)
+{
+   VerIterator Ver(Sim);
+ 
+   out << Pkg.FullName(true);
+
+   if (Current == true)
+   {
+      Ver = Pkg.CurrentVer();
+      if (Ver.end() == false)
+         out << " [" << Ver.VerStr() << ']';
+   }
+
+   if (Candidate == true)
+   {
+      Ver = Sim[Pkg].CandidateVerIter(Sim);
+      if (Ver.end() == true)
+         return;
+   
+      out << " (" << Ver.VerStr() << ' ' << Ver.RelStr() << ')';
+   }
+}
+									/*}}}*/
+// Simulate::Install - Simulate unpacking of a package			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSimulate::Install(PkgIterator iPkg,string File)
+{
+   if (iPkg.end() || File.empty())
+      return false;
+   d->List.emplace_back(pkgDPkgPM::Item::Install, iPkg, File);
+   return true;
+}
+bool pkgSimulate::RealInstall(PkgIterator iPkg,string /*File*/)
+{
+   // Adapt the iterator
+   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
+   Flags[Pkg->ID] = 1;
+   
+   cout << "Inst ";
+   Describe(Pkg,cout,true,true);
+   Sim.MarkInstall(Pkg,false);
+
+   // Look for broken conflicts+predepends.
+   for (PkgIterator I = Sim.PkgBegin(); I.end() == false; ++I)
+   {
+      if (Sim[I].InstallVer == 0)
+	 continue;
+      
+      for (DepIterator D = Sim[I].InstVerIter(Sim).DependsList(); D.end() == false;)
+      {
+	 DepIterator Start;
+	 DepIterator End;
+	 D.GlobOr(Start,End);
+	 if (Start.IsNegative() == true ||
+	     End->Type == pkgCache::Dep::PreDepends)
+         {
+	    if ((Sim[End] & pkgDepCache::DepGInstall) == 0)
+	    {
+	       cout << " [" << I.FullName(false) << " on " << Start.TargetPkg().FullName(false) << ']';
+	       if (Start->Type == pkgCache::Dep::Conflicts)
+		  _error->Error("Fatal, conflicts violated %s",I.FullName(false).c_str());
+	    }	    
+	 }
+      }      
+   }
+
+   if (Sim.BrokenCount() != 0)
+      ShortBreaks();
+   else
+      cout << endl;
+   return true;
+}
+									/*}}}*/
+// Simulate::Configure - Simulate configuration of a Package		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is not an accurate simulation of relatity, we should really not
+   install the package.. For some investigations it may be necessary 
+   however. */
+bool pkgSimulate::Configure(PkgIterator iPkg)
+{
+   if (iPkg.end())
+      return false;
+   d->List.emplace_back(pkgDPkgPM::Item::Configure, iPkg);
+   return true;
+}
+bool pkgSimulate::RealConfigure(PkgIterator iPkg)
+{
+   // Adapt the iterator
+   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
+   
+   Flags[Pkg->ID] = 2;
+
+   if (Sim[Pkg].InstBroken() == true)
+   {
+      cout << "Conf " << Pkg.FullName(false) << " broken" << endl;
+
+      Sim.Update();
+      
+      // Print out each package and the failed dependencies
+      for (pkgCache::DepIterator D = Sim[Pkg].InstVerIter(Sim).DependsList(); D.end() == false; ++D)
+      {
+	 if (Sim.IsImportantDep(D) == false || 
+	     (Sim[D] & pkgDepCache::DepInstall) != 0)
+	    continue;
+	 
+	 if (D->Type == pkgCache::Dep::Obsoletes)
+	    cout << " Obsoletes:" << D.TargetPkg().FullName(false);
+	 else if (D->Type == pkgCache::Dep::Conflicts)
+	    cout << " Conflicts:" << D.TargetPkg().FullName(false);
+	 else if (D->Type == pkgCache::Dep::DpkgBreaks)
+	    cout << " Breaks:" << D.TargetPkg().FullName(false);
+	 else
+	    cout << " Depends:" << D.TargetPkg().FullName(false);
+      }	    
+      cout << endl;
+
+      _error->Error("Conf Broken %s",Pkg.FullName(false).c_str());
+   }   
+   else
+   {
+      cout << "Conf "; 
+      Describe(Pkg,cout,false,true);
+   }
+
+   if (Sim.BrokenCount() != 0)
+      ShortBreaks();
+   else
+      cout << endl;
+   
+   return true;
+}
+									/*}}}*/
+// Simulate::Remove - Simulate the removal of a package			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSimulate::Remove(PkgIterator iPkg,bool Purge)
+{
+   if (iPkg.end())
+      return false;
+   d->List.emplace_back(Purge ? pkgDPkgPM::Item::Purge : pkgDPkgPM::Item::Remove, iPkg);
+   return true;
+}
+bool pkgSimulate::RealRemove(PkgIterator iPkg,bool Purge)
+{
+   // Adapt the iterator
+   PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
+   if (Pkg.end() == true)
+   {
+      std::cerr << (Purge ? "Purg" : "Remv") << " invalid package " << iPkg.FullName() << std::endl;
+      return false;
+   }
+
+   Flags[Pkg->ID] = 3;
+   Sim.MarkDelete(Pkg);
+
+   if (Purge == true)
+      cout << "Purg ";
+   else
+      cout << "Remv ";
+   Describe(Pkg,cout,true,false);
+
+   if (Sim.BrokenCount() != 0)
+      ShortBreaks();
+   else
+      cout << endl;
+
+   return true;
+}
+									/*}}}*/
+// Simulate::ShortBreaks - Print out a short line describing all breaks	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgSimulate::ShortBreaks()
+{
+   cout << " [";
+   for (PkgIterator I = Sim.PkgBegin(); I.end() == false; ++I)
+   {
+      if (Sim[I].InstBroken() == true)
+      {
+	 if (Flags[I->ID] == 0)
+	    cout << I.FullName(false) << ' ';
+/*	 else
+	    cout << I.Name() << "! ";*/
+      }      
+   }
+   cout << ']' << endl;
+}
+									/*}}}*/
+bool pkgSimulate::Go(APT::Progress::PackageManager *)			/*{{{*/
+{
+   if (pkgDPkgPM::ExpandPendingCalls(d->List, Cache) == false)
+      return false;
+   for (auto && I : d->List)
+      switch (I.Op)
+      {
+	 case pkgDPkgPM::Item::Install:
+	    if (RealInstall(I.Pkg, I.File) == false)
+	       return false;
+	    break;
+	 case pkgDPkgPM::Item::Configure:
+	    if (RealConfigure(I.Pkg) == false)
+	       return false;
+	    break;
+	 case pkgDPkgPM::Item::Remove:
+	    if (RealRemove(I.Pkg, false) == false)
+	       return false;
+	    break;
+	 case pkgDPkgPM::Item::Purge:
+	    if (RealRemove(I.Pkg, true) == false)
+	       return false;
+	    break;
+	 case pkgDPkgPM::Item::ConfigurePending:
+	 case pkgDPkgPM::Item::TriggersPending:
+	 case pkgDPkgPM::Item::RemovePending:
+	 case pkgDPkgPM::Item::PurgePending:
+	    return _error->Error("Internal error, simulation encountered unexpected pending item");
+      }
+   return true;
+}
+									/*}}}*/
+// ApplyStatus - Adjust for non-ok packages				/*{{{*/
+// ---------------------------------------------------------------------
+/* We attempt to change the state of the all packages that have failed
+   installation toward their real state. The ordering code will perform 
+   the necessary calculations to deal with the problems. */
+bool pkgApplyStatus(pkgDepCache &Cache)
+{
+   pkgDepCache::ActionGroup group(Cache);
+
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (I->VersionList == 0)
+	 continue;
+	 
+      // Only choice for a ReInstReq package is to reinstall
+      if (I->InstState == pkgCache::State::ReInstReq ||
+	  I->InstState == pkgCache::State::HoldReInstReq)
+      {
+	 if (I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true)
+	    Cache.MarkKeep(I, false, false);
+	 else
+	 {
+	    // Is this right? Will dpkg choke on an upgrade?
+	    if (Cache[I].CandidateVer != 0 &&
+		 Cache[I].CandidateVerIter(Cache).Downloadable() == true)
+	       Cache.MarkInstall(I, false, 0, false);
+	    else
+	       return _error->Error(_("The package %s needs to be reinstalled, "
+				    "but I can't find an archive for it."),I.FullName(true).c_str());
+	 }
+	 
+	 continue;
+      }
+      
+      switch (I->CurrentState)
+      {
+	 /* This means installation failed somehow - it does not need to be
+	    re-unpacked (probably) */
+	 case pkgCache::State::UnPacked:
+	 case pkgCache::State::HalfConfigured:
+	 case pkgCache::State::TriggersAwaited:
+	 case pkgCache::State::TriggersPending:
+	 if ((I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true) ||
+	     I.State() != pkgCache::PkgIterator::NeedsUnpack)
+	    Cache.MarkKeep(I, false, false);
+	 else
+	 {
+	    if (Cache[I].CandidateVer != 0 &&
+		 Cache[I].CandidateVerIter(Cache).Downloadable() == true)
+	       Cache.MarkInstall(I, true, 0, false);
+	    else
+	       Cache.MarkDelete(I, false, 0, false);
+	 }
+	 break;
+
+	 // This means removal failed
+	 case pkgCache::State::HalfInstalled:
+	 Cache.MarkDelete(I, false, 0, false);
+	 break;
+	 
+	 default:
+	 if (I->InstState != pkgCache::State::Ok)
+	    return _error->Error("The package %s is not ok and I "
+				 "don't know how to fix it!",I.FullName(false).c_str());
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// FixBroken - Fix broken packages					/*{{{*/
+// ---------------------------------------------------------------------
+/* This autoinstalls every broken package and then runs the problem resolver
+   on the result. */
+bool pkgFixBroken(pkgDepCache &Cache)
+{
+   pkgDepCache::ActionGroup group(Cache);
+
+   // Auto upgrade all broken packages
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (Cache[I].NowBroken() == true)
+	 Cache.MarkInstall(I, true, 0, false);
+   
+   /* Fix packages that are in a NeedArchive state but don't have a
+      downloadable install version */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (I.State() != pkgCache::PkgIterator::NeedsUnpack ||
+	  Cache[I].Delete() == true)
+	 continue;
+      
+      if (Cache[I].InstVerIter(Cache).Downloadable() == false)
+	 continue;
+
+      Cache.MarkInstall(I, true, 0, false);
+   }
+   
+   pkgProblemResolver Fix(&Cache);
+   return Fix.Resolve(true);
+}
+									/*}}}*/
+// ProblemResolver::pkgProblemResolver - Constructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgProblemResolver::pkgProblemResolver(pkgDepCache *pCache) : d(NULL), Cache(*pCache)
+{
+   // Allocate memory
+   auto const Size = Cache.Head().PackageCount;
+   Scores = new int[Size];
+   Flags = new unsigned char[Size];
+   memset(Flags,0,sizeof(*Flags)*Size);
+   
+   // Set debug to true to see its decision logic
+   Debug = _config->FindB("Debug::pkgProblemResolver",false);
+}
+									/*}}}*/
+// ProblemResolver::~pkgProblemResolver - Destructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgProblemResolver::~pkgProblemResolver()
+{
+   delete [] Scores;
+   delete [] Flags;
+}
+									/*}}}*/
+// ProblemResolver::ScoreSort - Sort the list by score			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+int pkgProblemResolver::ScoreSort(Package const *A,Package const *B)
+{
+   if (Scores[A->ID] > Scores[B->ID])
+      return -1;
+   if (Scores[A->ID] < Scores[B->ID])
+      return 1;
+   return 0;
+}
+									/*}}}*/
+// ProblemResolver::MakeScores - Make the score table			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgProblemResolver::MakeScores()
+{
+   auto const Size = Cache.Head().PackageCount;
+   memset(Scores,0,sizeof(*Scores)*Size);
+
+   // maps to pkgCache::State::VerPriority: 
+   //    Required Important Standard Optional Extra
+   int PrioMap[] = {
+      0,
+      _config->FindI("pkgProblemResolver::Scores::Required",3),
+      _config->FindI("pkgProblemResolver::Scores::Important",2),
+      _config->FindI("pkgProblemResolver::Scores::Standard",1),
+      _config->FindI("pkgProblemResolver::Scores::Optional",-1),
+      _config->FindI("pkgProblemResolver::Scores::Extra",-2)
+   };
+   int PrioEssentials = _config->FindI("pkgProblemResolver::Scores::Essentials",100);
+   int PrioInstalledAndNotObsolete = _config->FindI("pkgProblemResolver::Scores::NotObsolete",1);
+   int DepMap[] = {
+      0,
+      _config->FindI("pkgProblemResolver::Scores::Depends",1),
+      _config->FindI("pkgProblemResolver::Scores::PreDepends",1),
+      _config->FindI("pkgProblemResolver::Scores::Suggests",0),
+      _config->FindI("pkgProblemResolver::Scores::Recommends",1),
+      _config->FindI("pkgProblemResolver::Scores::Conflicts",-1),
+      _config->FindI("pkgProblemResolver::Scores::Replaces",0),
+      _config->FindI("pkgProblemResolver::Scores::Obsoletes",0),
+      _config->FindI("pkgProblemResolver::Scores::Breaks",-1),
+      _config->FindI("pkgProblemResolver::Scores::Enhances",0)
+   };
+   int AddProtected = _config->FindI("pkgProblemResolver::Scores::AddProtected",10000);
+   int AddEssential = _config->FindI("pkgProblemResolver::Scores::AddEssential",5000);
+
+   if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
+      clog << "Settings used to calculate pkgProblemResolver::Scores::" << endl
+         << "  Required => " << PrioMap[pkgCache::State::Required] << endl
+         << "  Important => " << PrioMap[pkgCache::State::Important] << endl
+         << "  Standard => " << PrioMap[pkgCache::State::Standard] << endl
+         << "  Optional => " << PrioMap[pkgCache::State::Optional] << endl
+         << "  Extra => " << PrioMap[pkgCache::State::Extra] << endl
+         << "  Essentials => " << PrioEssentials << endl
+         << "  InstalledAndNotObsolete => " << PrioInstalledAndNotObsolete << endl
+         << "  Pre-Depends => " << DepMap[pkgCache::Dep::PreDepends] << endl
+         << "  Depends => " << DepMap[pkgCache::Dep::Depends] << endl
+         << "  Recommends => " << DepMap[pkgCache::Dep::Recommends] << endl
+         << "  Suggests => " << DepMap[pkgCache::Dep::Suggests] << endl
+         << "  Conflicts => " << DepMap[pkgCache::Dep::Conflicts] << endl
+         << "  Breaks => " << DepMap[pkgCache::Dep::DpkgBreaks] << endl
+         << "  Replaces => " << DepMap[pkgCache::Dep::Replaces] << endl
+         << "  Obsoletes => " << DepMap[pkgCache::Dep::Obsoletes] << endl
+         << "  Enhances => " << DepMap[pkgCache::Dep::Enhances] << endl
+         << "  AddProtected => " << AddProtected << endl
+         << "  AddEssential => " << AddEssential << endl;
+
+   // Generate the base scores for a package based on its properties
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (Cache[I].InstallVer == 0)
+	 continue;
+      
+      int &Score = Scores[I->ID];
+      
+      /* This is arbitrary, it should be high enough to elevate an
+         essantial package above most other packages but low enough
+	 to allow an obsolete essential packages to be removed by
+	 a conflicts on a powerful normal package (ie libc6) */
+      if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential
+	  || (I->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
+	 Score += PrioEssentials;
+
+      pkgCache::VerIterator const InstVer = Cache[I].InstVerIter(Cache);
+      // We apply priorities only to downloadable packages, all others are prio:extra
+      // as an obsolete prio:standard package can't be that standard anymore…
+      if (InstVer->Priority <= pkgCache::State::Extra && InstVer.Downloadable() == true)
+	 Score += PrioMap[InstVer->Priority];
+      else
+	 Score += PrioMap[pkgCache::State::Extra];
+
+      /* This helps to fix oddball problems with conflicting packages
+	 on the same level. We enhance the score of installed packages
+	 if those are not obsolete */
+      if (I->CurrentVer != 0 && Cache[I].CandidateVer != 0 && Cache[I].CandidateVerIter(Cache).Downloadable())
+	 Score += PrioInstalledAndNotObsolete;
+
+      // propagate score points along dependencies
+      for (pkgCache::DepIterator D = InstVer.DependsList(); not D.end(); ++D)
+      {
+	 if (DepMap[D->Type] == 0)
+	    continue;
+	 pkgCache::PkgIterator const T = D.TargetPkg();
+	 if (not D.IsIgnorable(T))
+	 {
+	    if (D->Version != 0)
+	    {
+	       pkgCache::VerIterator const IV = Cache[T].InstVerIter(Cache);
+	       if (IV.end() || not D.IsSatisfied(IV))
+		  continue;
+	    }
+	    Scores[T->ID] += DepMap[D->Type];
+	 }
+
+	 std::vector<map_id_t> providers;
+	 for (auto Prv = T.ProvidesList(); not Prv.end(); ++Prv)
+	 {
+	    if (D.IsIgnorable(Prv))
+	       continue;
+	    auto const PV = Prv.OwnerVer();
+	    auto const PP = PV.ParentPkg();
+	    if (PV != Cache[PP].InstVerIter(Cache) || not D.IsSatisfied(Prv))
+	       continue;
+	    providers.push_back(PP->ID);
+	 }
+	 std::sort(providers.begin(), providers.end());
+	 providers.erase(std::unique(providers.begin(), providers.end()), providers.end());
+	 for (auto const prv : providers)
+	    Scores[prv] += DepMap[D->Type];
+      }
+   }
+
+   // Copy the scores to advoid additive looping
+   std::unique_ptr<int[]> OldScores(new int[Size]);
+   memcpy(OldScores.get(),Scores,sizeof(*Scores)*Size);
+      
+   /* Now we cause 1 level of dependency inheritance, that is we add the 
+      score of the packages that depend on the target Package. This 
+      fortifies high scoring packages */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (Cache[I].InstallVer == 0)
+	 continue;
+      
+      for (pkgCache::DepIterator D = I.RevDependsList(); D.end() == false; ++D)
+      {
+	 // Only do it for the install version
+	 if ((pkgCache::Version *)D.ParentVer() != Cache[D.ParentPkg()].InstallVer ||
+	     (D->Type != pkgCache::Dep::Depends && 
+	      D->Type != pkgCache::Dep::PreDepends &&
+	      D->Type != pkgCache::Dep::Recommends))
+	    continue;	 
+	 
+	 // Do not propagate negative scores otherwise
+	 // an extra (-2) package might score better than an optional (-1)
+	 if (OldScores[D.ParentPkg()->ID] > 0)
+	     Scores[I->ID] += OldScores[D.ParentPkg()->ID];
+      }      
+   }
+
+   /* Now we propagate along provides. This makes the packages that
+      provide important packages extremely important */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      auto const transfer = abs(Scores[I->ID] - OldScores[I->ID]);
+      if (transfer == 0)
+	 continue;
+
+      std::vector<map_id_t> providers;
+      for (auto Prv = I.ProvidesList(); not Prv.end(); ++Prv)
+      {
+	 if (Prv.IsMultiArchImplicit())
+	    continue;
+	 auto const PV = Prv.OwnerVer();
+	 auto const PP = PV.ParentPkg();
+	 if (PV != Cache[PP].InstVerIter(Cache))
+	    continue;
+	 providers.push_back(PP->ID);
+      }
+      std::sort(providers.begin(), providers.end());
+      providers.erase(std::unique(providers.begin(), providers.end()), providers.end());
+      for (auto const prv : providers)
+	 Scores[prv] += transfer;
+   }
+
+   /* Protected things are pushed really high up. This number should put them
+      ahead of everything */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if ((Flags[I->ID] & Protected) != 0)
+	 Scores[I->ID] += AddProtected;
+      if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential ||
+          (I->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
+	 Scores[I->ID] += AddEssential;
+   }
+}
+									/*}}}*/
+// ProblemResolver::DoUpgrade - Attempt to upgrade this package		/*{{{*/
+// ---------------------------------------------------------------------
+/* This goes through and tries to reinstall packages to make this package
+   installable */
+bool pkgProblemResolver::DoUpgrade(pkgCache::PkgIterator Pkg)
+{
+   pkgDepCache::ActionGroup group(Cache);
+
+   if ((Flags[Pkg->ID] & Upgradable) == 0 || Cache[Pkg].Upgradable() == false)
+      return false;
+   if ((Flags[Pkg->ID] & Protected) == Protected)
+      return false;
+   
+   Flags[Pkg->ID] &= ~Upgradable;
+   
+   bool WasKept = Cache[Pkg].Keep();
+   if (not Cache.MarkInstall(Pkg, false, 0, false))
+     return false;
+
+   // This must be a virtual package or something like that.
+   if (Cache[Pkg].InstVerIter(Cache).end() == true)
+      return false;
+   
+   // Isolate the problem dependency
+   bool Fail = false;
+   for (pkgCache::DepIterator D = Cache[Pkg].InstVerIter(Cache).DependsList(); D.end() == false;)
+   {
+      // Compute a single dependency element (glob or)
+      pkgCache::DepIterator Start = D;
+      pkgCache::DepIterator End = D;
+      for (bool LastOR = true; D.end() == false && LastOR == true;)
+      {
+	 LastOR = (D->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or;
+	 ++D;
+	 if (LastOR == true)
+	    End = D;
+      }
+      
+      // We only worry about critical deps.
+      if (End.IsCritical() != true)
+	 continue;
+            
+      // Iterate over all the members in the or group
+      while (1)
+      {
+	 // Dep is ok now
+	 if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
+	    break;
+	 
+	 // Do not change protected packages
+	 PkgIterator P = Start.SmartTargetPkg();
+	 if (Cache[P].Protect())
+	 {
+	    if (Debug == true)
+	       clog << "    Reinst Failed because of protected " << P.FullName(false) << endl;
+	    Fail = true;
+	 }      
+	 else
+	 {
+	    // Upgrade the package if the candidate version will fix the problem.
+	    if ((Cache[Start] & pkgDepCache::DepCVer) == pkgDepCache::DepCVer)
+	    {
+	       if (DoUpgrade(P) == false)
+	       {
+		  if (Debug == true)
+		     clog << "    Reinst Failed because of " << P.FullName(false) << endl;
+		  Fail = true;
+	       }
+	       else
+	       {
+		  Fail = false;
+		  break;
+	       }	    
+	    }
+	    else
+	    {
+	       /* We let the algorithm deal with conflicts on its next iteration,
+		it is much smarter than us */
+	       if (Start.IsNegative() == true)
+		   break;
+	       
+	       if (Debug == true)
+		  clog << "    Reinst Failed early because of " << Start.TargetPkg().FullName(false) << endl;
+	       Fail = true;
+	    }     
+	 }
+	 
+	 if (Start == End)
+	    break;
+	 ++Start;
+      }
+      if (Fail == true)
+	 break;
+   }
+   
+   // Undo our operations - it might be smart to undo everything this did..
+   if (Fail == true)
+   {
+      if (WasKept == true)
+	 Cache.MarkKeep(Pkg, false, false);
+      else
+	 Cache.MarkDelete(Pkg, false, 0, false);
+      return false;
+   }	 
+   
+   if (Debug == true)
+      clog << "  Re-Instated " << Pkg.FullName(false) << endl;
+   return true;
+}
+									/*}}}*/
+// ProblemResolver::Resolve - calls a resolver to fix the situation	/*{{{*/
+bool pkgProblemResolver::Resolve(bool BrokenFix, OpProgress * const Progress)
+{
+   std::string const solver = _config->Find("APT::Solver", "internal");
+   auto const ret = EDSP::ResolveExternal(solver.c_str(), Cache, 0, Progress);
+   if (solver != "internal")
+      return ret;
+   return ResolveInternal(BrokenFix);
+}
+									/*}}}*/
+// ProblemResolver::ResolveInternal - Run the resolution pass		/*{{{*/
+// ---------------------------------------------------------------------
+/* This routines works by calculating a score for each package. The score
+   is derived by considering the package's priority and all reverse 
+   dependents giving an integer that reflects the amount of breakage that
+   adjusting the package will inflict. 
+      
+   It goes from highest score to lowest and corrects all of the breaks by 
+   keeping or removing the dependent packages. If that fails then it removes
+   the package itself and goes on. The routine should be able to intelligently
+   go from any broken state to a fixed state. 
+ 
+   The BrokenFix flag enables a mode where the algorithm tries to 
+   upgrade packages to advoid problems. */
+bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
+{
+   pkgDepCache::ActionGroup group(Cache);
+
+   if (Debug)
+      Cache.CheckConsistency("resolve start");
+
+   // Record which packages are marked for install
+   bool Again = false;
+   do
+   {
+      Again = false;
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      {
+	 if (Cache[I].Install() == true)
+	    Flags[I->ID] |= PreInstalled;
+	 else
+	 {
+	    if (Cache[I].InstBroken() == true && BrokenFix == true)
+	    {
+	       Cache.MarkInstall(I, false, 0, false);
+	       if (Cache[I].Install() == true)
+		  Again = true;
+	    }
+	    
+	    Flags[I->ID] &= ~PreInstalled;
+	 }
+	 Flags[I->ID] |= Upgradable;
+      }
+   }
+   while (Again == true);
+
+   if (Debug == true) {
+      clog << "Starting pkgProblemResolver with broken count: " 
+           << Cache.BrokenCount() << endl;
+   }
+   
+   MakeScores();
+
+   auto const Size = Cache.Head().PackageCount;
+
+   /* We have to order the packages so that the broken fixing pass 
+      operates from highest score to lowest. This prevents problems when
+      high score packages cause the removal of lower score packages that
+      would cause the removal of even lower score packages. */
+   std::unique_ptr<pkgCache::Package *[]> PList(new pkgCache::Package *[Size]);
+   pkgCache::Package **PEnd = PList.get();
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      *PEnd++ = I;
+
+   std::sort(PList.get(), PEnd, [this](Package *a, Package *b) { return ScoreSort(a, b) < 0; });
+
+   if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
+   {
+      clog << "Show Scores" << endl;
+      for (pkgCache::Package **K = PList.get(); K != PEnd; K++)
+         if (Scores[(*K)->ID] != 0)
+         {
+           pkgCache::PkgIterator Pkg(Cache,*K);
+           clog << Scores[(*K)->ID] << ' ' << APT::PrettyPkg(&Cache, Pkg) << std::endl;
+         }
+   }
+
+   if (Debug == true) {
+      clog << "Starting 2 pkgProblemResolver with broken count: " 
+           << Cache.BrokenCount() << endl;
+   }
+
+   /* Now consider all broken packages. For each broken package we either
+      remove the package or fix it's problem. We do this once, it should
+      not be possible for a loop to form (that is a < b < c and fixing b by
+      changing a breaks c) */
+   bool Change = true;
+   bool const TryFixByInstall = _config->FindB("pkgProblemResolver::FixByInstall", true);
+   int const MaxCounter = _config->FindI("pkgProblemResolver::MaxCounter", 20);
+   std::vector<PackageKill> KillList;
+   for (int Counter = 0; Counter < MaxCounter && Change; ++Counter)
+   {
+      Change = false;
+      for (pkgCache::Package **K = PList.get(); K != PEnd; K++)
+      {
+	 pkgCache::PkgIterator I(Cache,*K);
+
+	 /* We attempt to install this and see if any breaks result,
+	    this takes care of some strange cases */
+	 if (Cache[I].CandidateVer != Cache[I].InstallVer &&
+	     I->CurrentVer != 0 && Cache[I].InstallVer != 0 &&
+	     (Flags[I->ID] & PreInstalled) != 0 &&
+	     not Cache[I].Protect() &&
+	     (Flags[I->ID] & ReInstateTried) == 0)
+	 {
+	    if (Debug == true)
+	       clog << " Try to Re-Instate (" << Counter << ") " << I.FullName(false) << endl;
+	    auto const OldBreaks = Cache.BrokenCount();
+	    pkgCache::Version *OldVer = Cache[I].InstallVer;
+	    Flags[I->ID] &= ReInstateTried;
+	    
+	    Cache.MarkInstall(I, false, 0, false);
+	    if (Cache[I].InstBroken() == true || 
+		OldBreaks < Cache.BrokenCount())
+	    {
+	       if (OldVer == 0)
+		  Cache.MarkDelete(I, false, 0, false);
+	       else
+		  Cache.MarkKeep(I, false, false);
+	    }	    
+	    else
+	       if (Debug == true)
+		  clog << "Re-Instated " << I.FullName(false) << " (" << OldBreaks << " vs " << Cache.BrokenCount() << ')' << endl;
+	 }
+	    
+	 if (Cache[I].InstallVer == 0 || Cache[I].InstBroken() == false)
+	    continue;
+	 
+	 if (Debug == true)
+	    clog << "Investigating (" << Counter << ") " << APT::PrettyPkg(&Cache, I) << endl;
+	 
+	 // Isolate the problem dependency
+	 bool InOr = false;
+	 pkgCache::DepIterator Start;
+	 pkgCache::DepIterator End;
+	 size_t OldSize = 0;
+
+	 KillList.clear();
+	 
+	 enum {OrRemove,OrKeep} OrOp = OrRemove;
+	 for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList();
+	      D.end() == false || InOr == true;)
+	 {
+	    // Compute a single dependency element (glob or)
+	    if (Start == End)
+	    {
+	       // Decide what to do
+	       if (InOr == true && OldSize == KillList.size())
+	       {
+		  if (OrOp == OrRemove)
+		  {
+		     if (not Cache[I].Protect())
+		     {
+			if (Debug == true)
+			   clog << "  Or group remove for " << I.FullName(false) << endl;
+			Cache.MarkDelete(I, false, 0, false);
+			Change = true;
+		     }
+		  }
+		  else if (OrOp == OrKeep)
+		  {
+		     if (Debug == true)
+			clog << "  Or group keep for " << I.FullName(false) << endl;
+		     Cache.MarkKeep(I, false, false);
+		     Change = true;
+		  }
+	       }
+	       
+	       /* We do an extra loop (as above) to finalize the or group
+		  processing */
+	       InOr = false;
+	       OrOp = OrRemove;
+	       D.GlobOr(Start,End);
+	       if (Start.end() == true)
+		  break;
+
+	       // We only worry about critical deps.
+	       if (End.IsCritical() != true)
+		  continue;
+
+	       InOr = Start != End;
+	       OldSize = KillList.size();
+	    }
+	    else
+            {
+	       ++Start;
+	       // We only worry about critical deps.
+	       if (Start.IsCritical() != true)
+                  continue;
+            }
+
+	    // Dep is ok
+	    if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
+	    {
+	       InOr = false;
+	       continue;
+	    }
+	    
+	    if (Debug == true)
+	       clog << "Broken " << APT::PrettyDep(&Cache, Start) << endl;
+
+	    /* Look across the version list. If there are no possible
+	       targets then we keep the package and bail. This is necessary
+	       if a package has a dep on another package that can't be found */
+	    std::unique_ptr<pkgCache::Version *[]> VList(Start.AllTargets());
+	    if (VList[0] == 0 && not Cache[I].Protect() &&
+		Start.IsNegative() == false &&
+		Cache[I].NowBroken() == false)
+	    {	       
+	       if (InOr == true)
+	       {
+		  /* No keep choice because the keep being OK could be the
+		     result of another element in the OR group! */
+		  continue;
+	       }
+	       
+	       Change = true;
+	       Cache.MarkKeep(I, false, false);
+	       break;
+	    }
+	    
+	    bool Done = false;
+	    for (pkgCache::Version **V = VList.get(); *V != 0; V++)
+	    {
+	       pkgCache::VerIterator Ver(Cache,*V);
+	       pkgCache::PkgIterator Pkg = Ver.ParentPkg();
+
+               /* This is a conflicts, and the version we are looking
+                  at is not the currently selected version of the 
+                  package, which means it is not necessary to 
+                  remove/keep */
+               if (Cache[Pkg].InstallVer != Ver && Start.IsNegative() == true)
+               {
+                  if (Debug) 
+                     clog << "  Conflicts//Breaks against version " 
+                          << Ver.VerStr() << " for " << Pkg.Name() 
+                          << " but that is not InstVer, ignoring"
+                          << endl;
+                  continue;
+               }
+
+	       if (Debug == true)
+		  clog << "  Considering " << Pkg.FullName(false) << ' ' << Scores[Pkg->ID] <<
+		  " as a solution to " << I.FullName(false) << ' ' << Scores[I->ID] << endl;
+
+	       /* Try to fix the package under consideration rather than
+	          fiddle with the VList package */
+	       if (Scores[I->ID] <= Scores[Pkg->ID] ||
+		   ((Cache[Start] & pkgDepCache::DepNow) == 0 &&
+		    End.IsNegative() == false))
+	       {
+		  // Try a little harder to fix protected packages..
+		  if (Cache[I].Protect())
+		  {
+		     if (DoUpgrade(Pkg) == true)
+		     {
+			if (Scores[Pkg->ID] > Scores[I->ID])
+			   Scores[Pkg->ID] = Scores[I->ID];
+			break;
+		     }
+		     
+		     continue;
+		  }
+		  
+		  /* See if a keep will do, unless the package is protected,
+		     then installing it will be necessary */
+		  bool Installed = Cache[I].Install();
+		  Cache.MarkKeep(I, false, false);
+		  if (Cache[I].InstBroken() == false)
+		  {
+		     // Unwind operation will be keep now
+		     if (OrOp == OrRemove)
+			OrOp = OrKeep;
+		     
+		     // Restore
+		     if (InOr == true && Installed == true)
+			Cache.MarkInstall(I, false, 0, false);
+		     
+		     if (Debug == true)
+			clog << "  Holding Back " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
+		  }		  
+		  else
+		  {		     
+		     if (BrokenFix == false || DoUpgrade(I) == false)
+		     {
+			// Consider other options
+			if (InOr == false || Cache[I].Garbage == true)
+			{
+			   if (Debug == true)
+			      clog << "  Removing " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
+			   Cache.MarkDelete(I, false, 0, false);
+			   if (Counter > 1 && Scores[Pkg->ID] > Scores[I->ID])
+			      Scores[I->ID] = Scores[Pkg->ID];
+			}
+			else if (TryFixByInstall == true &&
+				 Start.TargetPkg()->CurrentVer == 0 &&
+				 Cache[Start.TargetPkg()].Delete() == false &&
+				 (Flags[Start.TargetPkg()->ID] & ToRemove) != ToRemove &&
+				 Cache.GetCandidateVersion(Start.TargetPkg()).end() == false)
+			{
+			   /* Before removing or keeping the package with the broken dependency
+			      try instead to install the first not previously installed package
+			      solving this dependency. This helps every time a previous solver
+			      is removed by the resolver because of a conflict or alike but it is
+			      dangerous as it could trigger new breaks/conflicts… */
+			   if (Debug == true)
+			      clog << "  Try Installing " << APT::PrettyPkg(&Cache, Start.TargetPkg()) << " before changing " << I.FullName(false) << std::endl;
+			   auto const OldBroken = Cache.BrokenCount();
+			   Cache.MarkInstall(Start.TargetPkg(), true, 1, false);
+			   // FIXME: we should undo the complete MarkInstall process here
+			   if (Cache[Start.TargetPkg()].InstBroken() == true || Cache.BrokenCount() > OldBroken)
+			      Cache.MarkDelete(Start.TargetPkg(), false, 1, false);
+			}
+		     }
+		  }
+		  		  
+		  Change = true;
+		  Done = true;
+		  break;
+	       }
+	       else
+	       {
+		  if (Start->Type == pkgCache::Dep::DpkgBreaks)
+		  {
+		     // first, try upgradring the package, if that
+		     // does not help, the breaks goes onto the
+		     // kill list
+                     //
+		     // FIXME: use DoUpgrade(Pkg) instead?
+		     if (Cache[End] & pkgDepCache::DepGCVer)
+		     {
+			if (Debug)
+			   clog << "  Upgrading " << Pkg.FullName(false) << " due to Breaks field in " << I.FullName(false) << endl;
+			Cache.MarkInstall(Pkg, false, 0, false);
+			continue;
+		     }
+		  }
+
+		  // Skip adding to the kill list if it is protected
+		  if (Cache[Pkg].Protect() && Cache[Pkg].Mode != pkgDepCache::ModeDelete)
+		     continue;
+		
+		  if (Debug == true)
+		     clog << "  Added " << Pkg.FullName(false) << " to the remove list" << endl;
+
+		  KillList.push_back({Pkg, End});
+		  
+		  if (Start.IsNegative() == false)
+		     break;
+	       }
+	    }
+
+	    // Hm, nothing can possibly satisfy this dep. Nuke it.
+	    if (VList[0] == 0 &&
+		Start.IsNegative() == false &&
+		not Cache[I].Protect())
+	    {
+	       bool Installed = Cache[I].Install();
+	       Cache.MarkKeep(I);
+	       if (Cache[I].InstBroken() == false)
+	       {
+		  // Unwind operation will be keep now
+		  if (OrOp == OrRemove)
+		     OrOp = OrKeep;
+		  
+		  // Restore
+		  if (InOr == true && Installed == true)
+		     Cache.MarkInstall(I, false, 0, false);
+		  
+		  if (Debug == true)
+		     clog << "  Holding Back " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
+	       }	       
+	       else
+	       {
+		  if (Debug == true)
+		     clog << "  Removing " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
+		  if (InOr == false)
+		     Cache.MarkDelete(I, false, 0, false);
+	       }
+
+	       Change = true;
+	       Done = true;
+	    }
+	    
+	    // Try some more
+	    if (InOr == true)
+	       continue;
+	    
+	    if (Done == true)
+	       break;
+	 }
+	 
+	 // Apply the kill list now
+	 if (Cache[I].InstallVer != 0)
+	 {
+	    for (auto const &J : KillList)
+	    {
+	       bool foundSomething = false;
+	       if ((Cache[J.Dep] & pkgDepCache::DepGNow) == 0)
+	       {
+		  if (J.Dep.IsNegative() && Cache.MarkDelete(J.Pkg, false, 0, false))
+		  {
+		     if (Debug)
+			std::clog << "  Fixing " << I.FullName(false) << " via remove of " << J.Pkg.FullName(false) << '\n';
+		     foundSomething = true;
+		  }
+	       }
+	       else if (Cache.MarkKeep(J.Pkg, false, false))
+	       {
+		  if (Debug)
+		     std::clog << "  Fixing " << I.FullName(false) << " via keep of " << J.Pkg.FullName(false) << '\n';
+		  foundSomething = true;
+	       }
+
+	       if (not foundSomething || Counter > 1)
+	       {
+		  if (Scores[I->ID] > Scores[J.Pkg->ID])
+		  {
+		     Scores[J.Pkg->ID] = Scores[I->ID];
+		     Change = true;
+		  }
+	       }
+	       if (foundSomething)
+		  Change = true;
+	    }
+	 }
+      }
+   }
+
+   if (Debug == true)
+      clog << "Done" << endl;
+      
+   if (Cache.BrokenCount() != 0)
+   {
+      // See if this is the result of a hold
+      pkgCache::PkgIterator I = Cache.PkgBegin();
+      for (;I.end() != true; ++I)
+      {
+	 if (Cache[I].InstBroken() == false)
+	    continue;
+	 if (not Cache[I].Protect())
+	    return _error->Error(_("Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages."));
+      }
+      return _error->Error(_("Unable to correct problems, you have held broken packages."));
+   }
+   
+   // set the auto-flags (mvo: I'm not sure if we _really_ need this)
+   pkgCache::PkgIterator I = Cache.PkgBegin();
+   for (;I.end() != true; ++I) {
+      if (Cache[I].NewInstall() && !(Flags[I->ID] & PreInstalled)) {
+	 if(_config->FindB("Debug::pkgAutoRemove",false)) {
+	    std::clog << "Resolve installed new pkg: " << I.FullName(false) 
+		      << " (now marking it as auto)" << std::endl;
+	 }
+	 Cache[I].Flags |= pkgCache::Flag::Auto;
+      }
+   }
+
+   if (Debug)
+      Cache.CheckConsistency("resolve done");
+
+   return true;
+}
+									/*}}}*/
+// ProblemResolver::BreaksInstOrPolicy - Check if the given pkg is broken/*{{{*/
+// ---------------------------------------------------------------------
+/* This checks if the given package is broken either by a hard dependency
+   (InstBroken()) or by introducing a new policy breakage e.g. new
+   unsatisfied recommends for a package that was in "policy-good" state
+
+   Note that this is not perfect as it will ignore further breakage
+   for already broken policy (recommends)
+*/
+bool pkgProblemResolver::InstOrNewPolicyBroken(pkgCache::PkgIterator I)
+{
+   // a broken install is always a problem
+   if (Cache[I].InstBroken() == true)
+   {
+      if (Debug == true)
+	 std::clog << "  Dependencies are not satisfied for " << APT::PrettyPkg(&Cache, I) << std::endl;
+      return true;
+   }
+
+   // a newly broken policy (recommends/suggests) is a problem
+   if (Cache[I].NowPolicyBroken() == false &&
+       Cache[I].InstPolicyBroken() == true)
+   {
+      if (Debug == true)
+	 std::clog << "  Policy breaks with upgrade of " << APT::PrettyPkg(&Cache, I) << std::endl;
+      return true;
+   }
+
+   return false;
+}
+									/*}}}*/
+// ProblemResolver::ResolveByKeep - Resolve problems using keep		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the work horse of the soft upgrade routine. It is very gentle
+   in that it does not install or remove any packages. It is assumed that the
+   system was non-broken previously. */
+bool pkgProblemResolver::ResolveByKeep(OpProgress * const Progress)
+{
+   std::string const solver = _config->Find("APT::Solver", "internal");
+   constexpr auto flags = EDSP::Request::UPGRADE_ALL | EDSP::Request::FORBID_NEW_INSTALL | EDSP::Request::FORBID_REMOVE;
+   auto const ret = EDSP::ResolveExternal(solver.c_str(), Cache, flags, Progress);
+   if (solver != "internal")
+      return ret;
+   return ResolveByKeepInternal();
+}
+									/*}}}*/
+// ProblemResolver::ResolveByKeepInternal - Resolve problems using keep	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the work horse of the soft upgrade routine. It is very gentle
+   in that it does not install or remove any packages. It is assumed that the
+   system was non-broken previously. */
+bool pkgProblemResolver::ResolveByKeepInternal()
+{
+   pkgDepCache::ActionGroup group(Cache);
+
+   if (Debug)
+      Cache.CheckConsistency("keep start");
+
+   MakeScores();
+
+   /* We have to order the packages so that the broken fixing pass 
+      operates from highest score to lowest. This prevents problems when
+      high score packages cause the removal of lower score packages that
+      would cause the removal of even lower score packages. */
+   auto Size = Cache.Head().PackageCount;
+   pkgCache::Package **PList = new pkgCache::Package *[Size];
+   pkgCache::Package **PEnd = PList;
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      *PEnd++ = I;
+
+   std::sort(PList,PEnd,[this](Package *a, Package *b) { return ScoreSort(a, b) < 0; });
+
+
+   if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
+   {
+      clog << "Show Scores" << endl;
+      for (pkgCache::Package **K = PList; K != PEnd; K++)
+         if (Scores[(*K)->ID] != 0)
+         {
+           pkgCache::PkgIterator Pkg(Cache,*K);
+           clog << Scores[(*K)->ID] << ' ' << APT::PrettyPkg(&Cache, Pkg) << std::endl;
+         }
+   }
+
+   if (Debug == true)
+      clog << "Entering ResolveByKeep" << endl;
+
+   // Consider each broken package 
+   pkgCache::Package **LastStop = 0;
+   for (pkgCache::Package **K = PList; K != PEnd; K++)
+   {
+      pkgCache::PkgIterator I(Cache,*K);
+
+      if (Cache[I].InstallVer == 0)
+	 continue;
+
+      if (InstOrNewPolicyBroken(I) == false)
+         continue;
+
+      /* Keep the package. If this works then great, otherwise we have
+	 to be significantly more aggressive and manipulate its dependencies */
+      if (not Cache[I].Protect())
+      {
+	 if (Debug == true)
+	    clog << "Keeping package " << I.FullName(false) << endl;
+	 Cache.MarkKeep(I, false, false);
+	 if (InstOrNewPolicyBroken(I) == false)
+	 {
+	    K = PList - 1;
+	    continue;
+	 }
+      }
+      
+      // Isolate the problem dependencies
+      for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList(); D.end() == false;)
+      {
+	 DepIterator Start;
+	 DepIterator End;
+	 D.GlobOr(Start,End);
+
+	 // We only worry about critical deps.
+	 if (End.IsCritical() != true)
+	    continue;
+	 
+	 // Dep is ok
+	 if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
+	    continue;
+
+	 /* Hm, the group is broken.. I suppose the best thing to do is to
+	    is to try every combination of keep/not-keep for the set, but that's
+	    slow, and this never happens, just be conservative and assume the
+	    list of ors is in preference and keep till it starts to work. */
+	 while (true)
+	 {
+	    if (Debug == true)
+	       clog << "Package " << I.FullName(false) << " " << APT::PrettyDep(&Cache, Start) << endl;
+
+	    // Look at all the possible provides on this package
+	    std::unique_ptr<pkgCache::Version *[]> VList(Start.AllTargets());
+	    for (pkgCache::Version **V = VList.get(); *V != 0; V++)
+	    {
+	       pkgCache::VerIterator Ver(Cache,*V);
+	       pkgCache::PkgIterator Pkg = Ver.ParentPkg();
+	       
+	       // It is not keepable
+	       if (Cache[Pkg].InstallVer == 0 ||
+		   Pkg->CurrentVer == 0)
+		  continue;
+
+	       if (not Cache[Pkg].Protect())
+	       {
+		  if (Debug == true)
+		     clog << "  Keeping Package " << Pkg.FullName(false) << " due to " << Start.DepType() << endl;
+		  Cache.MarkKeep(Pkg, false, false);
+	       }
+	       
+	       if (InstOrNewPolicyBroken(I) == false)
+		  break;
+	    }
+	    
+	    if (InstOrNewPolicyBroken(I) == false)
+	       break;
+
+	    if (Start == End)
+	       break;
+	    ++Start;
+	 }
+	      
+	 if (InstOrNewPolicyBroken(I) == false)
+	    break;
+      }
+
+      if (InstOrNewPolicyBroken(I) == true)
+	 continue;
+      
+      // Restart again.
+      if (K == LastStop) {
+          // I is an iterator based off our temporary package list,
+          // so copy the name we need before deleting the temporary list
+          std::string const LoopingPackage = I.FullName(false);
+          delete[] PList;
+          return _error->Error("Internal Error, pkgProblemResolver::ResolveByKeep is looping on package %s.", LoopingPackage.c_str());
+      }
+      LastStop = K;
+      K = PList - 1;
+   }
+
+   delete[] PList;
+
+   if (Debug)
+      Cache.CheckConsistency("keep done");
+
+   return true;
+}
+									/*}}}*/
+// PrioSortList - Sort a list of versions by priority			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is meant to be used in conjunction with AllTargets to get a list 
+   of versions ordered by preference. */
+
+struct PrioComp {
+   pkgCache &PrioCache;
+
+   explicit PrioComp(pkgCache &PrioCache) : PrioCache(PrioCache) {
+   }
+
+   bool operator() (pkgCache::Version * const &A, pkgCache::Version * const &B) {
+      return compare(A, B) < 0;
+   }
+
+   int compare(pkgCache::Version * const &A, pkgCache::Version * const &B) {
+      pkgCache::VerIterator L(PrioCache,A);
+      pkgCache::VerIterator R(PrioCache,B);
+
+      if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential &&
+	  (R.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential)
+	return 1;
+      if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential &&
+	  (R.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+	return -1;
+
+      if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important &&
+	  (R.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important)
+	return 1;
+      if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important &&
+	  (R.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
+	return -1;
+
+      if (L->Priority != R->Priority)
+	 return R->Priority - L->Priority;
+      return strcmp(L.ParentPkg().Name(),R.ParentPkg().Name());
+   }
+};
+
+void pkgPrioSortList(pkgCache &Cache,pkgCache::Version **List)
+{
+   unsigned long Count = 0;
+   for (pkgCache::Version **I = List; *I != 0; I++)
+      Count++;
+   std::sort(List,List+Count,PrioComp(Cache));
+}
+									/*}}}*/
+
+namespace APT
+{
+
+namespace KernelAutoRemoveHelper
+{
+
+// \brief Returns the uname from a kernel package name, or "" for non-kernel packages.
+std::string getUname(std::string const &packageName)
+{
+
+   static const constexpr char *const prefixes[] = {
+      "linux-image-",
+      "kfreebsd-image-",
+      "gnumach-image-",
+   };
+
+   for (auto prefix : prefixes)
+   {
+      if (likely(not APT::String::Startswith(packageName, prefix)))
+	 continue;
+      if (unlikely(APT::String::Endswith(packageName, "-dbgsym")))
+	 continue;
+      if (unlikely(APT::String::Endswith(packageName, "-dbg")))
+	 continue;
+
+      auto aUname = packageName.substr(strlen(prefix));
+
+      // aUname must start with [0-9]+\.
+      if (aUname.length() < 2)
+	 continue;
+      if (strchr("0123456789", aUname[0]) == nullptr)
+	 continue;
+      auto dot = aUname.find_first_not_of("0123456789");
+      if (dot == aUname.npos || aUname[dot] != '.')
+	 continue;
+
+      return aUname;
+   }
+
+   return "";
+}
+std::string GetProtectedKernelsRegex(pkgCache *cache, bool ReturnRemove)
+{
+   if (_config->FindB("APT::Protect-Kernels", true) == false)
+      return "";
+
+   struct CompareKernel
+   {
+      pkgCache *cache;
+      bool operator()(const std::string &a, const std::string &b) const
+      {
+	 return cache->VS->CmpVersion(a, b) < 0;
+      }
+   };
+   bool Debug = _config->FindB("Debug::pkgAutoRemove", false);
+   // kernel version -> list of unames
+   std::map<std::string, std::vector<std::string>, CompareKernel> version2unames(CompareKernel{cache});
+   // needs to be initialized to 0s, might not be set up.
+   utsname uts{};
+   std::string bootedVersion;
+
+   // Get currently booted version, but only when not on reproducible build.
+   if (getenv("SOURCE_DATE_EPOCH") == 0)
+   {
+      if (uname(&uts) != 0)
+	 abort();
+   }
+
+   auto VirtualKernelPkg = cache->FindPkg("$kernel", "any");
+   if (VirtualKernelPkg.end())
+      return "";
+
+   for (pkgCache::PrvIterator Prv = VirtualKernelPkg.ProvidesList(); Prv.end() == false; ++Prv)
+   {
+      auto Pkg = Prv.OwnerPkg();
+      if (likely(Pkg->CurrentVer == 0))
+	 continue;
+
+      auto pkgUname = APT::KernelAutoRemoveHelper::getUname(Pkg.Name());
+      auto pkgVersion = Pkg.CurrentVer().VerStr();
+
+      if (pkgUname.empty())
+	 continue;
+
+      if (Debug)
+	 std::clog << "Found kernel " << pkgUname << "(" << pkgVersion << ")" << std::endl;
+
+      version2unames[pkgVersion].push_back(pkgUname);
+
+      if (pkgUname == uts.release)
+	 bootedVersion = pkgVersion;
+   }
+
+   if (version2unames.size() == 0)
+      return "";
+
+   auto latest = version2unames.rbegin();
+   auto previous = latest;
+   ++previous;
+
+   std::set<std::string> keep;
+
+   if (not bootedVersion.empty())
+   {
+      if (Debug)
+	 std::clog << "Keeping booted kernel " << bootedVersion << std::endl;
+      keep.insert(bootedVersion);
+   }
+   if (latest != version2unames.rend())
+   {
+      if (Debug)
+	 std::clog << "Keeping latest kernel " << latest->first << std::endl;
+      keep.insert(latest->first);
+   }
+   if (keep.size() < 2 && previous != version2unames.rend())
+   {
+      if (Debug)
+	 std::clog << "Keeping previous kernel " << previous->first << std::endl;
+      keep.insert(previous->first);
+   }
+   // Escape special characters '.' and '+' in version strings so we can build a regular expression
+   auto escapeSpecial = [](std::string input) -> std::string {
+      for (size_t pos = 0; (pos = input.find_first_of(".+", pos)) != input.npos; pos += 2) {
+	 input.insert(pos, 1, '\\');
+      }
+      return input;
+   };
+   std::ostringstream ss;
+   for (auto &pattern : _config->FindVector("APT::VersionedKernelPackages"))
+   {
+      // Legacy compatibility: Always protected the booted uname and last installed uname
+      if (*uts.release)
+	 ss << "|^" << pattern << "-" << escapeSpecial(uts.release) << "$";
+      for (auto const &kernel : version2unames)
+      {
+	 if (ReturnRemove ? keep.find(kernel.first) == keep.end() : keep.find(kernel.first) != keep.end())
+	 {
+	    for (auto const &uname : kernel.second)
+	       ss << "|^" << pattern << "-" << escapeSpecial(uname) << "$";
+	 }
+      }
+   }
+
+   auto re_with_leading_or = ss.str();
+
+   if (re_with_leading_or.empty())
+      return "";
+
+   auto re = re_with_leading_or.substr(1);
+   if (Debug)
+      std::clog << "Kernel protection regex: " << re << "\n";
+
+   return re;
+}
+
+std::unique_ptr<APT::CacheFilter::Matcher> GetProtectedKernelsFilter(pkgCache *cache, bool returnRemove)
+{
+   auto regex = GetProtectedKernelsRegex(cache, returnRemove);
+
+   if (regex.empty())
+      return std::make_unique<APT::CacheFilter::FalseMatcher>();
+
+   return std::make_unique<APT::CacheFilter::PackageNameMatchesRegEx>(regex);
+}
+
+} // namespace KernelAutoRemoveHelper
+} // namespace APT
diff --git a/apt-pkg/algorithms.h b/apt-pkg/algorithms.h
new file mode 100644
index 0000000..12a77d4
--- /dev/null
+++ b/apt-pkg/algorithms.h
@@ -0,0 +1,164 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Algorithms - A set of misc algorithms
+   
+   This simulate class displays what the ordering code has done and
+   analyses it with a fresh new dependency cache. In this way we can
+   see all of the effects of an upgrade run.
+
+   pkgDistUpgrade computes an upgrade that causes as many packages as
+   possible to move to the newest version.
+   
+   pkgApplyStatus sets the target state based on the content of the status
+   field in the status file. It is important to get proper crash recovery.
+
+   pkgFixBroken corrects a broken system so that it is in a sane state.
+ 
+   pkgAllUpgrade attempts to upgrade as many packages as possible but
+   without installing new packages.
+   
+   The problem resolver class contains a number of complex algorithms
+   to try to best-guess an upgrade state. It solves the problem of 
+   maximizing the number of install state packages while having no broken
+   packages. 
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ALGORITHMS_H
+#define PKGLIB_ALGORITHMS_H
+
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <iostream>
+#include <memory>
+#include <string>
+
+#include <apt-pkg/macros.h>
+
+
+
+
+class pkgSimulatePrivate;
+class APT_PUBLIC pkgSimulate : public pkgPackageManager				/*{{{*/
+{
+   pkgSimulatePrivate * const d;
+   protected:
+
+   class APT_PUBLIC Policy : public pkgDepCache::Policy
+   {
+      pkgDepCache *Cache;
+      public:
+      
+      virtual VerIterator GetCandidateVer(PkgIterator const &Pkg) APT_OVERRIDE
+      {
+	 return (*Cache)[Pkg].CandidateVerIter(*Cache);
+      }
+      
+      explicit Policy(pkgDepCache *Cache) : Cache(Cache) {};
+   };
+   
+   unsigned char *Flags;
+   
+   Policy iPolicy;
+   pkgDepCache Sim;
+   pkgDepCache::ActionGroup group;
+
+   // The Actual installation implementation
+   virtual bool Install(PkgIterator Pkg,std::string File) APT_OVERRIDE;
+   virtual bool Configure(PkgIterator Pkg) APT_OVERRIDE;
+   virtual bool Remove(PkgIterator Pkg,bool Purge) APT_OVERRIDE;
+
+public:
+   bool Go(APT::Progress::PackageManager * progress) override;
+
+private:
+   APT_HIDDEN void ShortBreaks();
+   APT_HIDDEN void Describe(PkgIterator iPkg,std::ostream &out,bool Current,bool Candidate);
+   APT_HIDDEN bool RealInstall(PkgIterator Pkg,std::string File);
+   APT_HIDDEN bool RealConfigure(PkgIterator Pkg);
+   APT_HIDDEN bool RealRemove(PkgIterator Pkg,bool Purge);
+
+   public:
+
+   explicit pkgSimulate(pkgDepCache *Cache);
+   virtual ~pkgSimulate();
+};
+									/*}}}*/
+class APT_PUBLIC pkgProblemResolver						/*{{{*/
+{
+ private:
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   pkgDepCache &Cache;
+   typedef pkgCache::PkgIterator PkgIterator;
+   typedef pkgCache::VerIterator VerIterator;
+   typedef pkgCache::DepIterator DepIterator;
+   typedef pkgCache::PrvIterator PrvIterator;
+   typedef pkgCache::Version Version;
+   typedef pkgCache::Package Package;
+   
+   enum Flags {Protected = (1 << 0), PreInstalled = (1 << 1),
+               Upgradable = (1 << 2), ReInstateTried = (1 << 3),
+               ToRemove = (1 << 4)};
+   int *Scores;
+   unsigned char *Flags;
+   bool Debug;
+   
+   // Sort stuff
+   APT_HIDDEN int ScoreSort(Package const *A, Package const *B) APT_PURE;
+
+   struct APT_PUBLIC PackageKill
+   {
+      PkgIterator Pkg;
+      DepIterator Dep;
+   };
+
+   APT_HIDDEN void MakeScores();
+   APT_HIDDEN bool DoUpgrade(pkgCache::PkgIterator Pkg);
+
+   protected:
+   bool InstOrNewPolicyBroken(pkgCache::PkgIterator Pkg);
+
+   public:
+   
+   inline void Protect(pkgCache::PkgIterator Pkg) {Flags[Pkg->ID] |= Protected; Cache.MarkProtected(Pkg);};
+   inline void Remove(pkgCache::PkgIterator Pkg) {Flags[Pkg->ID] |= ToRemove;};
+   inline void Clear(pkgCache::PkgIterator Pkg) {Flags[Pkg->ID] &= ~(Protected | ToRemove);};
+
+   // Try to intelligently resolve problems by installing and removing packages
+   bool Resolve(bool BrokenFix = false, OpProgress * const Progress = NULL);
+   APT_HIDDEN bool ResolveInternal(bool const BrokenFix = false);
+
+   // Try to resolve problems only by using keep
+   bool ResolveByKeep(OpProgress * const Progress = NULL);
+   APT_HIDDEN bool ResolveByKeepInternal();
+
+   explicit pkgProblemResolver(pkgDepCache *Cache);
+   virtual ~pkgProblemResolver();
+};
+									/*}}}*/
+APT_PUBLIC bool pkgApplyStatus(pkgDepCache &Cache);
+APT_PUBLIC bool pkgFixBroken(pkgDepCache &Cache);
+
+APT_PUBLIC void pkgPrioSortList(pkgCache &Cache,pkgCache::Version **List);
+
+namespace APT
+{
+namespace KernelAutoRemoveHelper
+{
+// Public for linking to apt-private, but no A{P,B}I guarantee.
+APT_PUBLIC std::unique_ptr<APT::CacheFilter::Matcher> GetProtectedKernelsFilter(pkgCache *cache, bool returnRemove = false);
+std::string GetProtectedKernelsRegex(pkgCache *cache, bool ReturnRemove = false);
+std::string getUname(std::string const &packageName);
+
+} // namespace KernelAutoRemoveHelper
+
+} // namespace APT
+
+#endif
diff --git a/apt-pkg/apt-pkg.pc.in b/apt-pkg/apt-pkg.pc.in
new file mode 100644
index 0000000..c6491d9
--- /dev/null
+++ b/apt-pkg/apt-pkg.pc.in
@@ -0,0 +1,8 @@
+libdir=@CMAKE_INSTALL_FULL_LIBDIR@
+includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
+
+Name: apt-pkg
+Description: package management runtime library
+Version: @PROJECT_VERSION@
+Libs: -L${libdir} -lapt-pkg -pthread
+Cflags: -I${includedir}
diff --git a/apt-pkg/aptconfiguration.cc b/apt-pkg/aptconfiguration.cc
new file mode 100644
index 0000000..00a97a0
--- /dev/null
+++ b/apt-pkg/aptconfiguration.cc
@@ -0,0 +1,541 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Provide access methods to various configuration settings,
+   setup defaults and returns validate settings.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+									/*}}}*/
+namespace APT {
+// setDefaultConfigurationForCompressors				/*{{{*/
+static void setDefaultConfigurationForCompressors() {
+	// Set default application paths to check for optional compression types
+	_config->CndSet("Dir::Bin::gzip", "/bin/gzip");
+	_config->CndSet("Dir::Bin::bzip2", "/bin/bzip2");
+	_config->CndSet("Dir::Bin::xz", "/usr/bin/xz");
+	_config->CndSet("Dir::Bin::lz4", "/usr/bin/lz4");
+	_config->CndSet("Dir::Bin::zstd", "/usr/bin/zstd");
+	if (FileExists(_config->Find("Dir::Bin::xz")) == true) {
+		_config->Set("Dir::Bin::lzma", _config->Find("Dir::Bin::xz"));
+		_config->Set("APT::Compressor::lzma::Binary", "xz");
+		if (_config->Exists("APT::Compressor::lzma::CompressArg") == false) {
+			_config->Set("APT::Compressor::lzma::CompressArg::", "--format=lzma");
+			_config->Set("APT::Compressor::lzma::CompressArg::", "-6");
+		}
+		if (_config->Exists("APT::Compressor::lzma::UncompressArg") == false) {
+			_config->Set("APT::Compressor::lzma::UncompressArg::", "--format=lzma");
+			_config->Set("APT::Compressor::lzma::UncompressArg::", "-d");
+		}
+	} else {
+		_config->CndSet("Dir::Bin::lzma", "/usr/bin/lzma");
+		if (_config->Exists("APT::Compressor::lzma::CompressArg") == false) {
+			_config->Set("APT::Compressor::lzma::CompressArg::", "--suffix=");
+			_config->Set("APT::Compressor::lzma::CompressArg::", "-6");
+		}
+		if (_config->Exists("APT::Compressor::lzma::UncompressArg") == false) {
+			_config->Set("APT::Compressor::lzma::UncompressArg::", "--suffix=");
+			_config->Set("APT::Compressor::lzma::UncompressArg::", "-d");
+		}
+	}
+	// setup the defaults for the compressiontypes => method mapping
+	_config->CndSet("Acquire::CompressionTypes::xz","xz");
+	_config->CndSet("Acquire::CompressionTypes::bz2","bzip2");
+	_config->CndSet("Acquire::CompressionTypes::lzma","lzma");
+	_config->CndSet("Acquire::CompressionTypes::gz","gzip");
+	_config->CndSet("Acquire::CompressionTypes::lz4","lz4");
+	_config->CndSet("Acquire::CompressionTypes::zst", "zstd");
+}
+									/*}}}*/
+// getCompressionTypes - Return Vector of usable compressiontypes	/*{{{*/
+// ---------------------------------------------------------------------
+/* return a vector of compression types in the preferred order. */
+std::vector<std::string>
+const Configuration::getCompressionTypes(bool const &Cached) {
+	static std::vector<std::string> types;
+	if (types.empty() == false) {
+		if (Cached == true)
+			return types;
+		else
+			types.clear();
+	}
+
+	std::vector<APT::Configuration::Compressor> const compressors = getCompressors();
+
+	// load the order setting into our vector
+	std::vector<std::string> const order = _config->FindVector("Acquire::CompressionTypes::Order");
+	for (std::vector<std::string>::const_iterator o = order.begin();
+	     o != order.end(); ++o) {
+		if ((*o).empty() == true)
+			continue;
+		// ignore types we have no method ready to use
+		std::string const method = std::string("Acquire::CompressionTypes::").append(*o);
+		if (_config->Exists(method) == false)
+			continue;
+		// ignore types we have no app ready to use
+		std::string const app = _config->Find(method);
+		if (std::find_if(compressors.begin(), compressors.end(), [&app](APT::Configuration::Compressor const &c) {
+				return c.Name == app;
+			}) == compressors.end())
+			continue;
+		types.push_back(*o);
+	}
+
+	// move again over the option tree to add all missing compression types
+	::Configuration::Item const *Types = _config->Tree("Acquire::CompressionTypes");
+	if (Types != 0)
+		Types = Types->Child;
+
+	for (; Types != 0; Types = Types->Next) {
+		if (Types->Tag == "Order" || Types->Tag.empty() == true)
+			continue;
+		// ignore types we already have in the vector
+		if (std::find(types.begin(),types.end(),Types->Tag) != types.end())
+			continue;
+		// ignore types we have no app ready to use
+		if (std::find_if(compressors.begin(), compressors.end(), [&Types](APT::Configuration::Compressor const &c) {
+				return c.Name == Types->Value;
+			}) == compressors.end())
+			continue;
+		types.push_back(Types->Tag);
+	}
+
+	// add the special "uncompressed" type
+	if (std::find(types.begin(), types.end(), "uncompressed") == types.end())
+	{
+		std::string const uncompr = _config->Find("Dir::Bin::uncompressed", "");
+		if (uncompr.empty() == true || FileExists(uncompr) == true)
+			types.push_back("uncompressed");
+	}
+
+	return types;
+}
+									/*}}}*/
+// GetLanguages - Return Vector of Language Codes			/*{{{*/
+// ---------------------------------------------------------------------
+/* return a vector of language codes in the preferred order.
+   the special word "environment" will be replaced with the long and the short
+   code of the local settings and it will be insured that this will not add
+   duplicates. So in an german local the setting "environment, de_DE, en, de"
+   will result in "de_DE, de, en".
+   The special word "none" is the stopcode for the not-All code vector */
+std::vector<std::string> const Configuration::getLanguages(bool const &All,
+				bool const &Cached, char const ** const Locale) {
+	using std::string;
+
+	// The detection is boring and has a lot of cornercases,
+	// so we cache the results to calculated it only once.
+	std::vector<string> static allCodes;
+	std::vector<string> static codes;
+
+	// we have something in the cache
+	if (codes.empty() == false || allCodes.empty() == false) {
+		if (Cached == true) {
+			if(All == true && allCodes.empty() == false)
+				return allCodes;
+			else
+				return codes;
+		} else {
+			allCodes.clear();
+			codes.clear();
+		}
+	}
+
+	// Include all Language codes we have a Translation file for in /var/lib/apt/lists
+	// so they will be all included in the Cache.
+	std::vector<string> builtin;
+	DIR *D = opendir(_config->FindDir("Dir::State::lists").c_str());
+	if (D != NULL) {
+		builtin.push_back("none");
+		for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) {
+			string const name = SubstVar(Ent->d_name, "%5f", "_");
+			size_t const foundDash = name.rfind("-");
+			size_t const foundUnderscore = name.rfind("_", foundDash);
+			if (foundDash == string::npos || foundUnderscore == string::npos ||
+			    foundDash <= foundUnderscore ||
+			    name.substr(foundUnderscore+1, foundDash-(foundUnderscore+1)) != "Translation")
+				continue;
+			string const c = name.substr(foundDash+1);
+			if (unlikely(c.empty() == true) || c == "en")
+				continue;
+			// Skip unusual files, like backups or that alike
+			string::const_iterator s = c.begin();
+			for (;s != c.end(); ++s) {
+				if (isalpha(*s) == 0 && *s != '_')
+					break;
+			}
+			if (s != c.end())
+				continue;
+			if (std::find(builtin.begin(), builtin.end(), c) != builtin.end())
+				continue;
+			builtin.push_back(c);
+		}
+		closedir(D);
+	}
+
+	// FIXME: Remove support for the old APT::Acquire::Translation
+	// it was undocumented and so it should be not very widthly used
+	string const oldAcquire = _config->Find("APT::Acquire::Translation","");
+	if (oldAcquire.empty() == false && oldAcquire != "environment") {
+		// TRANSLATORS: the two %s are APT configuration options
+		_error->Notice("Option '%s' is deprecated. Please use '%s' instead, see 'man 5 apt.conf' for details.",
+				"APT::Acquire::Translation", "Acquire::Languages");
+		if (oldAcquire != "none")
+			codes.push_back(oldAcquire);
+		codes.push_back("en");
+		allCodes = codes;
+		for (std::vector<string>::const_iterator b = builtin.begin();
+		     b != builtin.end(); ++b)
+			if (std::find(allCodes.begin(), allCodes.end(), *b) == allCodes.end())
+				allCodes.push_back(*b);
+		if (All == true)
+			return allCodes;
+		else
+			return codes;
+	}
+
+	// get the environment language codes: LC_MESSAGES (and later LANGUAGE)
+	// we extract both, a long and a short code and then we will
+	// check if we actually need both (rare) or if the short is enough
+	string const envMsg = string(Locale == 0 ? ::setlocale(LC_MESSAGES, NULL) : *Locale);
+	size_t const lenShort = (envMsg.find('_') != string::npos) ? envMsg.find('_') : 2;
+	size_t const lenLong = (envMsg.find_first_of(".@") != string::npos) ? envMsg.find_first_of(".@") : (lenShort + 3);
+
+	string const envLong = envMsg.substr(0,lenLong);
+	string const envShort = envLong.substr(0,lenShort);
+
+	// It is very likely we will need the environment codes later,
+	// so let us generate them now from LC_MESSAGES and LANGUAGE
+	std::vector<string> environment;
+	if (envShort != "C") {
+		// take care of LC_MESSAGES
+		if (envLong != envShort)
+			environment.push_back(envLong);
+		environment.push_back(envShort);
+		// take care of LANGUAGE
+		const char *language_env = getenv("LANGUAGE") == 0 ? "" : getenv("LANGUAGE");
+		string envLang = Locale == 0 ? language_env : *(Locale+1);
+		if (envLang.empty() == false) {
+			std::vector<string> env = VectorizeString(envLang,':');
+			short addedLangs = 0; // add a maximum of 3 fallbacks from the environment
+			for (std::vector<string>::const_iterator e = env.begin();
+			     e != env.end() && addedLangs < 3; ++e) {
+				if (unlikely(e->empty() == true) || *e == "en")
+					continue;
+				if (*e == envLong || *e == envShort)
+					continue;
+				if (std::find(environment.begin(), environment.end(), *e) != environment.end())
+					continue;
+				++addedLangs;
+				environment.push_back(*e);
+			}
+		}
+	} else {
+		// cornercase: LANG=C, so we use only "en" Translation
+		environment.push_back("en");
+	}
+
+	std::vector<string> const lang = _config->FindVector("Acquire::Languages", "environment,en");
+	// the configs define the order, so add the environment
+	// then needed and ensure the codes are not listed twice.
+	bool noneSeen = false;
+	for (std::vector<string>::const_iterator l = lang.begin();
+	     l != lang.end(); ++l) {
+		if (*l == "environment") {
+			for (std::vector<string>::const_iterator e = environment.begin();
+			     e != environment.end(); ++e) {
+				if (std::find(allCodes.begin(), allCodes.end(), *e) != allCodes.end())
+					continue;
+				if (noneSeen == false)
+					codes.push_back(*e);
+				allCodes.push_back(*e);
+			}
+			continue;
+		} else if (*l == "none") {
+			noneSeen = true;
+			continue;
+		} else if (std::find(allCodes.begin(), allCodes.end(), *l) != allCodes.end())
+			continue;
+
+		if (noneSeen == false)
+			codes.push_back(*l);
+		allCodes.push_back(*l);
+	}
+
+	if (allCodes.empty() == false) {
+		for (std::vector<string>::const_iterator b = builtin.begin();
+		     b != builtin.end(); ++b)
+			if (std::find(allCodes.begin(), allCodes.end(), *b) == allCodes.end())
+				allCodes.push_back(*b);
+	} else {
+		// "none" was forced
+		allCodes.push_back("none");
+	}
+
+	if (All == true)
+		return allCodes;
+	else
+		return codes;
+}
+									/*}}}*/
+// checkLanguage - are we interested in the given Language?		/*{{{*/
+bool Configuration::checkLanguage(std::string Lang, bool const All) {
+	// the empty Language is always interesting as it is the original
+	if (Lang.empty() == true)
+		return true;
+	// filenames are encoded, so undo this
+	Lang = SubstVar(Lang, "%5f", "_");
+	std::vector<std::string> const langs = getLanguages(All, true);
+	return (std::find(langs.begin(), langs.end(), Lang) != langs.end());
+}
+									/*}}}*/
+// getArchitectures - Return Vector of preferred Architectures		/*{{{*/
+std::vector<std::string> const Configuration::getArchitectures(bool const &Cached) {
+	std::vector<std::string> static archs;
+	if (likely(Cached == true) && archs.empty() == false)
+		return archs;
+
+	std::string const arch = _config->Find("APT::Architecture");
+	archs = _config->FindVector("APT::Architectures");
+
+	if (archs.empty() == true && _system != nullptr)
+	   archs = _system->ArchitecturesSupported();
+
+	if (archs.empty() == true ||
+	    std::find(archs.begin(), archs.end(), arch) == archs.end())
+		archs.insert(archs.begin(), arch);
+
+	// erase duplicates, empty strings and very foreign architectures
+	auto newend = std::remove_if(archs.begin(), archs.end(), [](auto const &a) { return a.empty(); });
+	for (auto a = archs.begin(); a != newend; ++a)
+		newend = std::remove(std::next(a), newend, *a);
+	for (auto const &f : _config->FindVector("APT::BarbarianArchitectures"))
+		newend = std::remove(archs.begin(), newend, f);
+	archs.erase(newend, archs.end());
+	return archs;
+}
+									/*}}}*/
+// checkArchitecture - are we interested in the given Architecture?	/*{{{*/
+bool Configuration::checkArchitecture(std::string const &Arch) {
+	if (Arch == "all")
+		return true;
+	std::vector<std::string> const archs = getArchitectures(true);
+	return (std::find(archs.begin(), archs.end(), Arch) != archs.end());
+}
+									/*}}}*/
+// getCompressors - Return Vector of usealbe compressors		/*{{{*/
+// ---------------------------------------------------------------------
+/* return a vector of compressors used by apt-ftparchive in the
+   multicompress functionality or to detect data.tar files */
+std::vector<APT::Configuration::Compressor>
+const Configuration::getCompressors(bool const Cached) {
+	static std::vector<APT::Configuration::Compressor> compressors;
+	if (compressors.empty() == false) {
+		if (Cached == true)
+			return compressors;
+		else
+			compressors.clear();
+	}
+
+	setDefaultConfigurationForCompressors();
+
+	std::vector<std::string> CompressorsDone;
+# define APT_ADD_COMPRESSOR(NAME, EXT, BINARY, ARG, DEARG, COST) \
+	{ CompressorsDone.push_back(NAME); compressors.emplace_back(NAME, EXT, BINARY, ARG, DEARG, COST); }
+	APT_ADD_COMPRESSOR(".", "", "", nullptr, nullptr, 0)
+	if (_config->Exists("Dir::Bin::zstd") == false || FileExists(_config->Find("Dir::Bin::zstd")) == true)
+	   APT_ADD_COMPRESSOR("zstd", ".zst", "zstd", "-19", "-d", 60)
+#ifdef HAVE_ZSTD
+	else
+	   APT_ADD_COMPRESSOR("zstd", ".zst", "false", nullptr, nullptr, 60)
+#endif
+	if (_config->Exists("Dir::Bin::lz4") == false || FileExists(_config->Find("Dir::Bin::lz4")) == true)
+		APT_ADD_COMPRESSOR("lz4",".lz4","lz4","-1","-d",50)
+#ifdef HAVE_LZ4
+	else
+		APT_ADD_COMPRESSOR("lz4",".lz4","false", nullptr, nullptr, 50)
+#endif
+	if (_config->Exists("Dir::Bin::gzip") == false || FileExists(_config->Find("Dir::Bin::gzip")) == true)
+		APT_ADD_COMPRESSOR("gzip",".gz","gzip","-6n","-d",100)
+#ifdef HAVE_ZLIB
+	else
+		APT_ADD_COMPRESSOR("gzip",".gz","false", nullptr, nullptr, 100)
+#endif
+	if (_config->Exists("Dir::Bin::xz") == false || FileExists(_config->Find("Dir::Bin::xz")) == true)
+		APT_ADD_COMPRESSOR("xz",".xz","xz","-6","-d",200)
+#ifdef HAVE_LZMA
+	else
+		APT_ADD_COMPRESSOR("xz",".xz","false", nullptr, nullptr, 200)
+#endif
+	if (_config->Exists("Dir::Bin::bzip2") == false || FileExists(_config->Find("Dir::Bin::bzip2")) == true)
+		APT_ADD_COMPRESSOR("bzip2",".bz2","bzip2","-6","-d",300)
+#ifdef HAVE_BZ2
+	else
+		APT_ADD_COMPRESSOR("bzip2",".bz2","false", nullptr, nullptr, 300)
+#endif
+	if (_config->Exists("Dir::Bin::lzma") == false || FileExists(_config->Find("Dir::Bin::lzma")) == true)
+		APT_ADD_COMPRESSOR("lzma",".lzma","lzma","-6","-d",400)
+#ifdef HAVE_LZMA
+	else
+		APT_ADD_COMPRESSOR("lzma",".lzma","false", nullptr, nullptr, 400)
+#endif
+
+	std::vector<std::string> const comp = _config->FindVector("APT::Compressor", "", true);
+	for (auto const &c: comp)
+	{
+		if (c.empty() || std::find(CompressorsDone.begin(), CompressorsDone.end(), c) != CompressorsDone.end())
+			continue;
+		compressors.push_back(Compressor(c.c_str(), std::string(".").append(c).c_str(), c.c_str(), nullptr, nullptr, 1000));
+	}
+
+	return compressors;
+}
+									/*}}}*/
+// getCompressorExtensions - supported data.tar extensions		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+std::vector<std::string> const Configuration::getCompressorExtensions() {
+	std::vector<APT::Configuration::Compressor> const compressors = getCompressors();
+	std::vector<std::string> ext;
+	for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressors.begin();
+	     c != compressors.end(); ++c)
+		if (c->Extension.empty() == false && c->Extension != ".")
+			ext.push_back(c->Extension);
+	return ext;
+}
+									/*}}}*/
+// Compressor constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+Configuration::Compressor::Compressor(char const *name, char const *extension,
+				      char const *binary,
+				      char const *compressArg, char const *uncompressArg,
+				      unsigned short const cost) {
+	std::string const config = std::string("APT::Compressor::").append(name).append("::");
+	Name = _config->Find(std::string(config).append("Name"), name);
+	Extension = _config->Find(std::string(config).append("Extension"), extension);
+	Binary = _config->Find(std::string(config).append("Binary"), binary);
+	Cost = _config->FindI(std::string(config).append("Cost"), cost);
+	std::string const compConf = std::string(config).append("CompressArg");
+	if (_config->Exists(compConf) == true)
+		CompressArgs = _config->FindVector(compConf);
+	else if (compressArg != NULL)
+		CompressArgs.push_back(compressArg);
+	std::string const uncompConf = std::string(config).append("UncompressArg");
+	if (_config->Exists(uncompConf) == true)
+		UncompressArgs = _config->FindVector(uncompConf);
+	else if (uncompressArg != NULL)
+		UncompressArgs.push_back(uncompressArg);
+}
+									/*}}}*/
+// getBuildProfiles - return a vector of enabled build profiles		/*{{{*/
+std::vector<std::string> const Configuration::getBuildProfiles() {
+	// order is: override value (~= commandline), environment variable, list (~= config file)
+	std::string profiles_env = getenv("DEB_BUILD_PROFILES") == 0 ? "" : getenv("DEB_BUILD_PROFILES");
+	if (profiles_env.empty() == false) {
+		profiles_env = SubstVar(profiles_env, " ", ",");
+		std::string const bp = _config->Find("APT::Build-Profiles");
+		_config->Clear("APT::Build-Profiles");
+		if (bp.empty() == false)
+			_config->Set("APT::Build-Profiles", bp);
+	}
+	return _config->FindVector("APT::Build-Profiles", profiles_env);
+}
+std::string const Configuration::getBuildProfilesString() {
+	std::vector<std::string> profiles = getBuildProfiles();
+	if (profiles.empty() == true)
+		return "";
+	std::vector<std::string>::const_iterator p = profiles.begin();
+	std::string list = *p;
+	for (++p; p != profiles.end(); ++p)
+	   list.append(",").append(*p);
+	return list;
+}
+									/*}}}*/
+
+// getMachineID - read /etc/machine-id into a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+std::string const Configuration::getMachineID()
+{
+   std::string id = _config->Find("APT::Machine-ID");
+
+   if (id.empty())
+   {
+      std::string file = _config->FindFile("Dir::Etc::machine-id");
+
+      if (file.empty())
+      {
+	 file = flCombine(_config->FindDir("Dir::Etc"), "../machine-id");
+      }
+      FileFd fd;
+      _error->PushToStack();
+
+      if (not OpenConfigurationFileFd(file, fd) || not fd.ReadLine(id))
+      {
+	 if (_config->FindB("Debug::Phasing", false))
+	 {
+	    _error->DumpErrors(std::clog);
+	 }
+      }
+
+      _error->RevertToStack();
+   }
+
+   return id;
+}
+									/*}}}*/
+// isChroot - whether we are inside a chroot			     	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool Configuration::isChroot()
+{
+   static struct once
+   {
+      bool res = false;
+      once()
+      {
+	 pid_t child = ExecFork();
+	 if (child == 0)
+	 {
+	    auto binary = _config->FindFile("Dir::Bin::ischroot", "/usr/bin/ischroot");
+	    const char *const Args[] = {
+	       binary.c_str(),
+	       "-t",
+	       nullptr};
+	    execvp(Args[0], const_cast<char **>(Args));
+	    _exit(127);
+	 }
+
+	 res = ExecWait(child, "ischroot", true);
+      }
+   } once;
+
+   return once.res;
+}
+									/*}}}*/
+}
diff --git a/apt-pkg/aptconfiguration.h b/apt-pkg/aptconfiguration.h
new file mode 100644
index 0000000..bbeb156
--- /dev/null
+++ b/apt-pkg/aptconfiguration.h
@@ -0,0 +1,134 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/** \class APT::Configuration
+ *  \brief Provide access methods to various configuration settings
+ *
+ *  This class and their methods providing a layer around the usual access
+ *  methods with _config to ensure that settings are correct and to be able
+ *  to set defaults without the need to recheck it in every method again.
+ */
+									/*}}}*/
+#ifndef APT_CONFIGURATION_H
+#define APT_CONFIGURATION_H
+// Include Files							/*{{{*/
+#include <apt-pkg/macros.h>
+#include <limits>
+#include <string>
+#include <vector>
+									/*}}}*/
+namespace APT {
+namespace Configuration {							/*{{{*/
+	/** \brief Returns a vector of usable Compression Types
+	 *
+	 *  Files can be compressed in various ways to decrease the size of the
+	 *  download. Therefore the Acquiremethods support a few compression types
+	 *  and some archives provide also a few different types. This option
+	 *  group exists to give the user the choice to prefer one type over the
+	 *  other (some compression types are very resource intensive - great if you
+	 *  have a limited download, bad if you have a really lowpowered hardware.)
+	 *
+	 *  This method ensures that the defaults are set and checks at runtime
+	 *  if the type can be used. E.g. the current default is to prefer bzip2
+	 *  over lzma and gz - if the bzip2 binary is not available it has not much
+	 *  sense in downloading the bz2 file, therefore we will not return bz2 as
+	 *  a usable compression type. The availability is checked with the settings
+	 *  in the Dir::Bin group.
+	 *
+	 *  \param Cached saves the result so we need to calculated it only once
+	 *                this parameter should only be used for testing purposes.
+	 *
+	 *  \return a vector of the compression types in the preferred usage order
+	 */
+	APT_PUBLIC std::vector<std::string> const getCompressionTypes(bool const &Cached = true);
+
+	/** \brief Returns a vector of Language Codes
+	 *
+	 *  Languages can be defined with their two or five chars long code.
+	 *  This methods handles the various ways to set the preferred codes,
+	 *  honors the environment and ensures that the codes are not listed twice.
+	 *
+	 *  The special word "environment" will be replaced with the long and the short
+	 *  code of the local settings and it will be insured that this will not add
+	 *  duplicates. So in an german local the setting "environment, de_DE, en, de"
+	 *  will result in "de_DE, de, en".
+	 *
+	 *  Another special word is "none" which separates the preferred from all codes
+	 *  in this setting. So setting and method can be used to get codes the user want
+	 *  to see or to get all language codes APT (should) have Translations available.
+	 *
+	 *  \param All return all codes or only codes for languages we want to use
+	 *  \param Cached saves the result so we need to calculated it only once
+	 *                this parameter should only be used for testing purposes.
+	 *  \param Locale don't get the locale from the system but use this one instead
+	 *                this parameter should only be used for testing purposes.
+	 *
+	 *  \return a vector of (all) Language Codes in the preferred usage order
+	 */
+	APT_PUBLIC std::vector<std::string> const getLanguages(bool const &All = false,
+			bool const &Cached = true, char const ** const Locale = 0);
+
+	/** \brief Are we interested in the given Language?
+	 *
+	 *  \param Lang is the language we want to check
+	 *  \param All defines if we check against all codes or only against used codes
+	 *  \return true if we are interested, false otherwise
+	 */
+	APT_PUBLIC bool checkLanguage(std::string Lang, bool const All = false);
+
+	/** \brief Returns a vector of Architectures we support
+	 *
+	 *  \param Cached saves the result so we need to calculated it only once
+	 *                this parameter should only be used for testing purposes.
+	 *
+	 *  \return a vector of Architectures in preferred order
+	 */
+	APT_PUBLIC std::vector<std::string> const getArchitectures(bool const &Cached = true);
+
+	/** \brief Are we interested in the given Architecture?
+	 *
+	 *  \param Arch we want to check
+	 *  \return true if we are interested, false otherwise
+	 */
+	APT_PUBLIC bool checkArchitecture(std::string const &Arch);
+
+	/** \brief Representation of supported compressors */
+	struct APT_PUBLIC Compressor {
+		std::string Name;
+		std::string Extension;
+		std::string Binary;
+		std::vector<std::string> CompressArgs;
+		std::vector<std::string> UncompressArgs;
+		unsigned short Cost;
+
+		Compressor(char const *name, char const *extension, char const *binary,
+			   char const *compressArg, char const *uncompressArg,
+			   unsigned short const cost);
+		Compressor() : Cost(std::numeric_limits<unsigned short>::max()) {};
+	};
+
+	/** \brief Return a vector of Compressors supported for data.tar's
+	 *
+	 *  \param Cached saves the result so we need to calculated it only once
+	 *                this parameter should only be used for testing purposes.
+	 *
+	 *  \return a vector of Compressors
+	 */
+	APT_PUBLIC std::vector<Compressor> const getCompressors(bool const Cached = true);
+
+	/** \brief Return a vector of extensions supported for data.tar's */
+	APT_PUBLIC std::vector<std::string> const getCompressorExtensions();
+
+	/** \return Return a vector of enabled build profile specifications */
+	APT_PUBLIC std::vector<std::string> const getBuildProfiles();
+	/** \return Return a comma-separated list of enabled build profile specifications */
+	APT_PUBLIC std::string const getBuildProfilesString();
+
+	std::string const getMachineID();
+
+	/** \return Whether we are running in a chroot */
+	bool isChroot();
+	/*}}}*/
+}
+									/*}}}*/
+}
+#endif
diff --git a/apt-pkg/cachefile.cc b/apt-pkg/cachefile.cc
new file mode 100644
index 0000000..4c3cc95
--- /dev/null
+++ b/apt-pkg/cachefile.cc
@@ -0,0 +1,385 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   CacheFile - Simple wrapper class for opening, generating and whatnot
+   
+   This class implements a simple 2 line mechanism to open various sorts
+   of caches. It can operate as root, as not root, show progress and so on,
+   it transparently handles everything necessary.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/mmap.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/policy.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/sourcelist.h>
+
+#include <limits>
+#include <memory>
+#include <string>
+#include <vector>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+struct pkgCacheFile::Private
+{
+   bool WithLock = false;
+   bool InhibitActionGroups = false;
+};
+
+// CacheFile::CacheFile - Constructor					/*{{{*/
+pkgCacheFile::pkgCacheFile() : d(new Private()), ExternOwner(false), Map(NULL), Cache(NULL),
+				DCache(NULL), SrcList(NULL), Policy(NULL)
+{
+}
+pkgCacheFile::pkgCacheFile(pkgDepCache * const Owner) : d(new Private()), ExternOwner(true),
+   Map(&Owner->GetCache().GetMap()), Cache(&Owner->GetCache()),
+   DCache(Owner), SrcList(NULL), Policy(NULL)
+{
+}
+									/*}}}*/
+// CacheFile::~CacheFile - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgCacheFile::~pkgCacheFile()
+{
+   if (ExternOwner == false)
+   {
+      delete DCache;
+      delete Cache;
+      delete Map;
+   }
+   delete Policy;
+   delete SrcList;
+   if (d->WithLock == true)
+      _system->UnLock(true);
+
+   delete d;
+}
+									/*}}}*/
+// CacheFile::BuildCaches - Open and build the cache files		/*{{{*/
+class APT_HIDDEN ScopedErrorMerge {
+public:
+   ScopedErrorMerge() { _error->PushToStack(); }
+   ~ScopedErrorMerge() { _error->MergeWithStack(); }
+};
+
+bool pkgCacheFile::BuildCaches(OpProgress *Progress, bool WithLock)
+{
+   std::unique_ptr<pkgCache> Cache;
+   std::unique_ptr<MMap> Map;
+
+   if (this->Cache != NULL)
+      return true;
+
+   ScopedErrorMerge sem;
+   if (_config->FindB("pkgCacheFile::Generate", true) == false)
+   {
+      FileFd file(_config->FindFile("Dir::Cache::pkgcache"), FileFd::ReadOnly);
+      if (file.IsOpen() == false || file.Failed())
+	 return false;
+      Map.reset(new MMap(file, MMap::Public|MMap::ReadOnly));
+      if (unlikely(Map->validData() == false))
+	 return false;
+      Cache.reset(new pkgCache(Map.get()));
+      if (_error->PendingError() == true)
+	 return false;
+
+      this->Cache = Cache.release();
+      this->Map = Map.release();
+      return true;
+   }
+
+   if (WithLock == true)
+   {
+      if (_system->Lock(Progress) == false)
+	 return false;
+      d->WithLock = true;
+   }
+
+   if (_error->PendingError() == true)
+      return false;
+
+   if (BuildSourceList(Progress) == false)
+      return false;
+
+   // Read the caches
+   MMap *TmpMap = nullptr;
+   pkgCache *TmpCache = nullptr;
+   bool Res = pkgCacheGenerator::MakeStatusCache(*SrcList,Progress,&TmpMap, &TmpCache, true);
+   Map.reset(TmpMap);
+   Cache.reset(TmpCache);
+   if (Progress != NULL)
+      Progress->Done();
+   if (Res == false)
+      return _error->Error(_("The package lists or status file could not be parsed or opened."));
+
+   /* This sux, remove it someday */
+   if (_error->PendingError() == true)
+      _error->Warning(_("You may want to run apt-get update to correct these problems"));
+
+   if (Cache == nullptr)
+      Cache.reset(new pkgCache(Map.get()));
+   if (_error->PendingError() == true)
+      return false;
+   this->Map = Map.release();
+   this->Cache = Cache.release();
+
+   return true;
+}
+									/*}}}*/
+// CacheFile::BuildSourceList - Open and build all relevant sources.list/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheFile::BuildSourceList(OpProgress * /*Progress*/)
+{
+   std::unique_ptr<pkgSourceList> SrcList;
+   if (this->SrcList != NULL)
+      return true;
+
+   SrcList.reset(new pkgSourceList());
+   if (SrcList->ReadMainList() == false)
+      return _error->Error(_("The list of sources could not be read."));
+   this->SrcList = SrcList.release();
+   return true;
+}
+									/*}}}*/
+// CacheFile::BuildPolicy - Open and build all relevant preferences	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheFile::BuildPolicy(OpProgress * /*Progress*/)
+{
+   std::unique_ptr<pkgPolicy> Policy;
+   if (this->Policy != NULL)
+      return true;
+
+   Policy.reset(new pkgPolicy(Cache));
+   if (_error->PendingError() == true)
+      return false;
+
+   ReadPinFile(*Policy);
+   ReadPinDir(*Policy);
+
+   this->Policy = Policy.release();
+   return _error->PendingError() == false;
+}
+									/*}}}*/
+// CacheFile::BuildDepCache - Open and build the dependency cache	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheFile::BuildDepCache(OpProgress *Progress)
+{
+   if (BuildCaches(Progress, false) == false)
+      return false;
+
+   std::unique_ptr<pkgDepCache> DCache;
+   if (this->DCache != NULL)
+      return true;
+
+   if (BuildPolicy(Progress) == false)
+      return false;
+
+   DCache.reset(new pkgDepCache(Cache,Policy));
+   if (_error->PendingError() == true)
+      return false;
+   if (d->InhibitActionGroups)
+      DCache->IncreaseActionGroupLevel();
+   if (DCache->Init(Progress) == false)
+      return false;
+
+   this->DCache = DCache.release();
+   return true;
+}
+									/*}}}*/
+// CacheFile::Open - Open the cache files, creating if necessary	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheFile::Open(OpProgress *Progress, bool WithLock)
+{
+   if (BuildCaches(Progress,WithLock) == false)
+      return false;
+
+   if (BuildPolicy(Progress) == false)
+      return false;
+
+   if (BuildDepCache(Progress) == false)
+      return false;
+
+   if (Progress != NULL)
+      Progress->Done();
+   if (_error->PendingError() == true)
+      return false;
+   
+   return true;
+}
+									/*}}}*/
+bool pkgCacheFile::AddIndexFile(pkgIndexFile * const File)		/*{{{*/
+{
+   if (SrcList == NULL)
+      if (BuildSourceList() == false)
+	 return false;
+   SrcList->AddVolatileFile(File);
+
+   if (Cache == nullptr || File->HasPackages() == false || File->Exists() == false)
+      return true;
+
+   if (File->FindInCache(*Cache).end() == false)
+      return _error->Warning("Duplicate sources.list entry %s",
+	    File->Describe().c_str());
+
+   if (ExternOwner == false)
+   {
+      delete DCache;
+      delete Cache;
+   }
+   delete Policy;
+   DCache = NULL;
+   Policy = NULL;
+   Cache = NULL;
+
+   if (ExternOwner == false)
+   {
+      // a dynamic mmap means that we have build at least parts of the cache
+      // in memory – which we might or might not have written to disk.
+      // Throwing away would therefore be a very costly operation we want to avoid
+      DynamicMMap * dynmmap = dynamic_cast<DynamicMMap*>(Map);
+      if (dynmmap != nullptr)
+      {
+	 {
+	    pkgCacheGenerator Gen(dynmmap, nullptr);
+	    if (Gen.Start() == false || File->Merge(Gen, nullptr) == false)
+	       return false;
+	 }
+	 Cache = new pkgCache(Map);
+	 if (_error->PendingError() == true) {
+	    delete Cache;
+	    Cache = nullptr;
+	    return false;
+	 }
+	 return true;
+      }
+      else
+      {
+	 delete Map;
+	 Map = NULL;
+      }
+   }
+   else
+   {
+      ExternOwner = false;
+      Map = NULL;
+   }
+   _system->UnLock(true);
+   return true;
+}
+									/*}}}*/
+// CacheFile::RemoveCaches - remove all cache files from disk		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+static void SetCacheStartBeforeRemovingCache(std::string const &cache)
+{
+   if (cache.empty())
+      return;
+   auto const CacheStart = _config->FindI("APT::Cache-Start", 0);
+   constexpr auto CacheStartDefault = 24 * 1024 * 1024;
+   struct stat Buf;
+   if (stat(cache.c_str(), &Buf) == 0 && (Buf.st_mode & S_IFREG) != 0)
+   {
+      RemoveFile("RemoveCaches", cache);
+      if (CacheStart == 0 && std::numeric_limits<decltype(CacheStart)>::max() >= Buf.st_size && Buf.st_size > CacheStartDefault)
+	 _config->Set("APT::Cache-Start", Buf.st_size);
+   }
+}
+void pkgCacheFile::RemoveCaches()
+{
+   std::string const pkgcache = _config->FindFile("Dir::cache::pkgcache");
+   SetCacheStartBeforeRemovingCache(pkgcache);
+   std::string const srcpkgcache = _config->FindFile("Dir::cache::srcpkgcache");
+   SetCacheStartBeforeRemovingCache(srcpkgcache);
+
+   if (pkgcache.empty() == false)
+   {
+      std::string cachedir = flNotFile(pkgcache);
+      std::string cachefile = flNotDir(pkgcache);
+      if (cachedir.empty() != true && cachefile.empty() != true && DirectoryExists(cachedir) == true)
+      {
+	 cachefile.append(".");
+	 std::vector<std::string> caches = GetListOfFilesInDir(cachedir, false);
+	 for (std::vector<std::string>::const_iterator file = caches.begin(); file != caches.end(); ++file)
+	 {
+	    std::string nuke = flNotDir(*file);
+	    if (strncmp(cachefile.c_str(), nuke.c_str(), cachefile.length()) != 0)
+	       continue;
+	    RemoveFile("RemoveCaches", *file);
+	 }
+      }
+   }
+
+   if (srcpkgcache.empty() == true)
+      return;
+
+   std::string cachedir = flNotFile(srcpkgcache);
+   std::string cachefile = flNotDir(srcpkgcache);
+   if (cachedir.empty() == true || cachefile.empty() == true || DirectoryExists(cachedir) == false)
+      return;
+   cachefile.append(".");
+   std::vector<std::string> caches = GetListOfFilesInDir(cachedir, false);
+   for (std::vector<std::string>::const_iterator file = caches.begin(); file != caches.end(); ++file)
+   {
+      std::string nuke = flNotDir(*file);
+      if (strncmp(cachefile.c_str(), nuke.c_str(), cachefile.length()) != 0)
+	 continue;
+      RemoveFile("RemoveCaches", *file);
+   }
+}
+									/*}}}*/
+// CacheFile::Close - close the cache files				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgCacheFile::Close()
+{
+   if (ExternOwner == false)
+   {
+      delete DCache;
+      delete Cache;
+      delete Map;
+   }
+   else
+      ExternOwner = false;
+   delete Policy;
+   delete SrcList;
+   if (d->WithLock == true)
+   {
+      _system->UnLock(true);
+      d->WithLock = false;
+   }
+
+   Map = NULL;
+   DCache = NULL;
+   Policy = NULL;
+   Cache = NULL;
+   SrcList = NULL;
+}
+									/*}}}*/
+void pkgCacheFile::InhibitActionGroups(bool const yes)
+{
+   d->InhibitActionGroups = yes;
+}
diff --git a/apt-pkg/cachefile.h b/apt-pkg/cachefile.h
new file mode 100644
index 0000000..4e26e6d
--- /dev/null
+++ b/apt-pkg/cachefile.h
@@ -0,0 +1,90 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   CacheFile - Simple wrapper class for opening, generating and whatnot
+   
+   This class implements a simple 2 line mechanism to open various sorts
+   of caches. It can operate as root, as not root, show progress and so on,
+   it transparently handles everything necessary.
+   
+   This means it can rebuild caches from the source list and instantiates
+   and prepares the standard policy mechanism.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CACHEFILE_H
+#define PKGLIB_CACHEFILE_H
+
+#include <stddef.h>
+
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+
+class MMap;
+class pkgPolicy;
+class pkgSourceList;
+class pkgIndexFile;
+class OpProgress;
+
+class APT_PUBLIC pkgCacheFile
+{
+   struct Private;
+   /** \brief dpointer placeholder (for later in case we need it) */
+   Private *const d;
+   bool ExternOwner;
+
+   protected:
+   MMap *Map;
+   pkgCache *Cache;
+   pkgDepCache *DCache;
+   pkgSourceList *SrcList;
+
+   public:
+   pkgPolicy *Policy;
+
+   // We look pretty much exactly like a pointer to a dep cache
+   inline operator pkgCache &() const {return *Cache;};
+   inline operator pkgCache *() const {return Cache;};
+   inline operator pkgDepCache &() const {return *DCache;};
+   inline operator pkgDepCache *() const {return DCache;};
+   inline operator pkgPolicy &() const {return *Policy;};
+   inline operator pkgPolicy *() const {return Policy;};
+   inline operator pkgSourceList &() const {return *SrcList;};
+   inline operator pkgSourceList *() const {return SrcList;};
+   inline pkgDepCache *operator ->() const {return DCache;};
+   inline pkgDepCache &operator *() const {return *DCache;};
+   inline pkgDepCache::StateCache &operator [](pkgCache::PkgIterator const &I) const {return (*DCache)[I];};
+   inline unsigned char &operator [](pkgCache::DepIterator const &I) const {return (*DCache)[I];};
+
+   bool BuildCaches(OpProgress *Progress = NULL,bool WithLock = true);
+   bool BuildSourceList(OpProgress *Progress = NULL);
+   bool BuildPolicy(OpProgress *Progress = NULL);
+   bool BuildDepCache(OpProgress *Progress = NULL);
+   bool Open(OpProgress *Progress = NULL, bool WithLock = true);
+   inline bool ReadOnlyOpen(OpProgress *Progress = NULL) { return Open(Progress, false); };
+   static void RemoveCaches();
+   void Close();
+
+   bool AddIndexFile(pkgIndexFile * const File);
+   // Starts DepCache with a claim of one ActionGroup already active
+   void InhibitActionGroups(bool yes);
+
+   inline pkgCache* GetPkgCache() { BuildCaches(NULL, false); return Cache; };
+   inline pkgDepCache* GetDepCache() { BuildDepCache(); return DCache; };
+   inline pkgPolicy* GetPolicy() { BuildPolicy(); return Policy; };
+   inline pkgSourceList* GetSourceList() { BuildSourceList(); return SrcList; };
+
+   inline bool IsPkgCacheBuilt() const { return (Cache != NULL); };
+   inline bool IsDepCacheBuilt() const { return (DCache != NULL); };
+   inline bool IsPolicyBuilt() const { return (Policy != NULL); };
+   inline bool IsSrcListBuilt() const { return (SrcList != NULL); };
+
+   pkgCacheFile();
+   explicit pkgCacheFile(pkgDepCache * const Owner);
+   virtual ~pkgCacheFile();
+};
+
+#endif
diff --git a/apt-pkg/cachefilter-patterns.cc b/apt-pkg/cachefilter-patterns.cc
new file mode 100644
index 0000000..faf5735
--- /dev/null
+++ b/apt-pkg/cachefilter-patterns.cc
@@ -0,0 +1,614 @@
+/*
+ * cachefilter-patterns.cc - Parser for aptitude-style patterns
+ *
+ * Copyright (c) 2019 Canonical Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <config.h>
+
+#include <apt-pkg/cachefilter-patterns.h>
+
+#include <apti18n.h>
+
+namespace APT
+{
+namespace Internal
+{
+
+static const constexpr struct
+{
+   APT::StringView shortName;
+   APT::StringView longName;
+   bool takesArgument;
+} shortPatterns[] = {
+   {"r"_sv, "?architecture"_sv, true},
+   {"A"_sv, "?archive"_sv, true},
+   {"M"_sv, "?automatic"_sv, false},
+   {"b"_sv, "?broken"_sv, false},
+   {"c"_sv, "?config-files"_sv, false},
+   // FIXME: The words after ~D should be case-insensitive
+   {"DDepends:"_sv, "?depends"_sv, true},
+   {"DPre-Depends:"_sv, "?pre-depends"_sv, true},
+   {"DSuggests:"_sv, "?suggests"_sv, true},
+   {"DRecommends:"_sv, "?recommends"_sv, true},
+   {"DConflicts:"_sv, "?conflicts"_sv, true},
+   {"DReplaces:"_sv, "?replaces"_sv, true},
+   {"DObsoletes:"_sv, "?obsoletes"_sv, true},
+   {"DBreaks:"_sv, "?breaks"_sv, true},
+   {"DEnhances:"_sv, "?enhances"_sv, true},
+   {"D"_sv, "?depends"_sv, true},
+   {"RDepends:"_sv, "?reverse-depends"_sv, true},
+   {"RPre-Depends:"_sv, "?reverse-pre-depends"_sv, true},
+   {"RSuggests:"_sv, "?reverse-suggests"_sv, true},
+   {"RRecommends:"_sv, "?reverse-recommends"_sv, true},
+   {"RConflicts:"_sv, "?reverse-conflicts"_sv, true},
+   {"RReplaces:"_sv, "?reverse-replaces"_sv, true},
+   {"RObsoletes:"_sv, "?reverse-obsoletes"_sv, true},
+   {"RBreaks:"_sv, "?reverse-breaks"_sv, true},
+   {"REnhances:"_sv, "?reverse-enhances"_sv, true},
+   {"R"_sv, "?reverse-depends"_sv, true},
+   {"E"_sv, "?essential"_sv, false},
+   {"F"_sv, "?false"_sv, false},
+   {"g"_sv, "?garbage"_sv, false},
+   {"i"_sv, "?installed"_sv, false},
+   {"n"_sv, "?name"_sv, true},
+   {"o"_sv, "?obsolete"_sv, false},
+   {"O"_sv, "?origin"_sv, true},
+   {"p"_sv, "?priority"_sv, true},
+   {"s"_sv, "?section"_sv, true},
+   {"e"_sv, "?source-package"_sv, true},
+   {"T"_sv, "?true"_sv, false},
+   {"U"_sv, "?upgradable"_sv, false},
+   {"V"_sv, "?version"_sv, true},
+   {"v"_sv, "?virtual"_sv, false},
+};
+
+template <class... Args>
+std::string rstrprintf(Args... args)
+{
+   std::string str;
+   strprintf(str, std::forward<Args>(args)...);
+   return str;
+}
+
+// Parse a complete pattern, make sure it's the entire input
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseTop()
+{
+   skipSpace();
+   auto node = parse();
+   skipSpace();
+
+   if (node == nullptr)
+      throw Error{Node{0, sentence.size()}, "Expected pattern"};
+
+   if (node->end != sentence.size())
+      throw Error{Node{node->end, sentence.size()}, "Expected end of file"};
+
+   return node;
+}
+
+// Parse any pattern
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parse()
+{
+   return parseOr();
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseOr()
+{
+   auto start = state.offset;
+   std::vector<std::unique_ptr<PatternTreeParser::Node>> nodes;
+
+   auto firstNode = parseAnd();
+
+   if (firstNode == nullptr)
+      return nullptr;
+
+   nodes.push_back(std::move(firstNode));
+   for (skipSpace(); sentence[state.offset] == '|'; skipSpace())
+   {
+      state.offset++;
+      skipSpace();
+      auto node = parseAnd();
+
+      if (node == nullptr)
+	 throw Error{Node{state.offset, sentence.size()}, "Expected pattern after |"};
+
+      nodes.push_back(std::move(node));
+   }
+
+   if (nodes.size() == 0)
+      return nullptr;
+   if (nodes.size() == 1)
+      return std::move(nodes[0]);
+
+   auto node = std::make_unique<PatternNode>();
+   node->start = start;
+   node->end = nodes[nodes.size() - 1]->end;
+   node->term = "?or";
+   node->arguments = std::move(nodes);
+   node->haveArgumentList = true;
+
+   return node;
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseAnd()
+{
+   auto start = state.offset;
+   std::vector<std::unique_ptr<PatternTreeParser::Node>> nodes;
+
+   for (skipSpace(); state.offset < sentence.size(); skipSpace())
+   {
+      auto node = parseUnary();
+
+      if (node == nullptr)
+	 break;
+
+      nodes.push_back(std::move(node));
+   }
+
+   if (nodes.size() == 0)
+      return nullptr;
+   if (nodes.size() == 1)
+      return std::move(nodes[0]);
+
+   auto node = std::make_unique<PatternNode>();
+   node->start = start;
+   node->end = nodes[nodes.size() - 1]->end;
+   node->term = "?and";
+   node->arguments = std::move(nodes);
+   node->haveArgumentList = true;
+
+   return node;
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseUnary()
+{
+
+   if (sentence[state.offset] != '!')
+      return parsePrimary();
+
+   auto start = ++state.offset;
+   auto primary = parsePrimary();
+
+   if (primary == nullptr)
+      throw Error{Node{start, sentence.size()}, "Expected pattern"};
+
+   auto node = std::make_unique<PatternNode>();
+   node->start = start;
+   node->end = primary->end;
+   node->term = "?not";
+   node->arguments.push_back(std::move(primary));
+   node->haveArgumentList = true;
+   return node;
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parsePrimary()
+{
+   std::unique_ptr<Node> node;
+   if ((node = parseShortPattern()) != nullptr)
+      return node;
+   if ((node = parsePattern()) != nullptr)
+      return node;
+   if ((node = parseGroup()) != nullptr)
+      return node;
+
+   return nullptr;
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseGroup()
+{
+   if (sentence[state.offset] != '(')
+      return nullptr;
+
+   auto start = state.offset++;
+
+   skipSpace();
+   auto node = parse();
+   if (node == nullptr)
+      throw Error{Node{state.offset, sentence.size()},
+		  "Expected pattern after '('"};
+   skipSpace();
+
+   if (sentence[state.offset] != ')')
+      throw Error{Node{state.offset, sentence.size()},
+		  "Expected closing parenthesis"};
+
+   auto end = ++state.offset;
+   node->start = start;
+   node->end = end;
+   return node;
+}
+
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseArgument(bool shrt)
+{
+   std::unique_ptr<Node> node;
+   if ((node = parseQuotedWord()) != nullptr)
+      return node;
+   if ((node = parseWord(shrt)) != nullptr)
+      return node;
+   if ((node = parse()) != nullptr)
+      return node;
+
+   throw Error{Node{state.offset, sentence.size()},
+	       "Expected pattern, quoted word, or word"};
+}
+
+// Parse a short pattern
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseShortPattern()
+{
+   if (sentence[state.offset] != '~')
+      return nullptr;
+
+   for (auto &sp : shortPatterns)
+   {
+      if (sentence.substr(state.offset + 1, sp.shortName.size()) != sp.shortName)
+	 continue;
+
+      auto node = std::make_unique<PatternNode>();
+      node->end = node->start = state.offset;
+      node->term = sp.longName;
+
+      state.offset += sp.shortName.size() + 1;
+      if (sp.takesArgument)
+      {
+	 node->arguments.push_back(parseArgument(true));
+	 node->haveArgumentList = true;
+      }
+      node->end = state.offset;
+
+      return node;
+   }
+
+   throw Error{Node{state.offset, sentence.size()}, "Unknown short pattern"};
+}
+
+// Parse a list pattern (or function call pattern)
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parsePattern()
+{
+   static constexpr auto CHARS = ("0123456789"
+				  "abcdefghijklmnopqrstuvwxyz"
+				  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+				  "-"_sv);
+   if (sentence[state.offset] != '?')
+      return nullptr;
+
+   auto node = std::make_unique<PatternNode>();
+   node->end = node->start = state.offset;
+   state.offset++;
+
+   while (CHARS.find(sentence[state.offset]) != APT::StringView::npos)
+   {
+      ++state.offset;
+   }
+
+   node->term = sentence.substr(node->start, state.offset - node->start);
+
+   if (node->term.size() <= 1)
+      throw Error{*node, "Pattern must have a term/name"};
+
+   node->end = skipSpace();
+   // We don't have any arguments, return node;
+   if (sentence[state.offset] != '(')
+      return node;
+   node->end = ++state.offset;
+   skipSpace();
+
+   node->haveArgumentList = true;
+
+   // Empty argument list, return
+   if (sentence[state.offset] == ')')
+   {
+      node->end = ++state.offset;
+      return node;
+   }
+
+   node->arguments.push_back(parseArgument(false));
+   skipSpace();
+   while (sentence[state.offset] == ',')
+   {
+      ++state.offset;
+      skipSpace();
+      // This was a trailing comma - allow it and break the loop
+      if (sentence[state.offset] == ')')
+	 break;
+      node->arguments.push_back(parseArgument(false));
+      skipSpace();
+   }
+
+   node->end = state.offset;
+   if (sentence[state.offset] != ')')
+      throw Error{node->arguments.empty() ? *node : *node->arguments[node->arguments.size() - 1],
+		  rstrprintf("Expected closing parenthesis or comma after last argument, received %c", sentence[state.offset])};
+
+   node->end = ++state.offset;
+   return node;
+}
+
+// Parse a quoted word atom
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseQuotedWord()
+{
+   if (sentence[state.offset] != '"')
+      return nullptr;
+
+   auto node = std::make_unique<WordNode>();
+   node->start = state.offset;
+
+   // Eat beginning of string
+   state.offset++;
+
+   while (sentence[state.offset] != '"' && sentence[state.offset] != '\0')
+      state.offset++;
+
+   // End of string
+   if (sentence[state.offset] != '"')
+      throw Error{*node, "Could not find end of string"};
+   state.offset++;
+
+   node->end = state.offset;
+   node->word = sentence.substr(node->start + 1, node->end - node->start - 2);
+
+   return node;
+}
+
+// Parse a bare word atom
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseWord(bool shrt)
+{
+   // Characters not allowed at the start of a word (also see ..._SHRT)
+   static const constexpr auto DISALLOWED_START = "!?~|,() \0"_sv;
+   // Characters terminating a word inside a long pattern
+   static const constexpr auto DISALLOWED_LONG = "|,()\0"_sv;
+   // Characters terminating a word as a short form argument, should contain all of START.
+   static const constexpr auto DISALLOWED_SHRT = "!?~|,() \0"_sv;
+   const auto DISALLOWED = shrt ? DISALLOWED_SHRT : DISALLOWED_LONG;
+
+   if (DISALLOWED_START.find(sentence[state.offset]) != APT::StringView::npos)
+      return nullptr;
+
+   auto node = std::make_unique<WordNode>();
+   node->start = state.offset;
+
+   while (DISALLOWED.find(sentence[state.offset]) == APT::StringView::npos)
+      state.offset++;
+
+   node->end = state.offset;
+   node->word = sentence.substr(node->start, node->end - node->start);
+   return node;
+}
+
+// Rendering of the tree in JSON for debugging
+std::ostream &PatternTreeParser::PatternNode::render(std::ostream &os)
+{
+
+   os << term.to_string();
+   if (haveArgumentList)
+   {
+      os << "(";
+      for (auto &node : arguments)
+	 node->render(os) << ",";
+      os << ")";
+   }
+   return os;
+}
+
+std::ostream &PatternTreeParser::WordNode::render(std::ostream &os)
+{
+   return quoted ? os << '"' << word.to_string() << '"' : os << word.to_string();
+}
+
+std::nullptr_t PatternTreeParser::Node::error(std::string message)
+{
+   throw Error{*this, message};
+}
+
+bool PatternTreeParser::PatternNode::matches(APT::StringView name, int min, int max)
+{
+   if (name != term)
+      return false;
+   if (max != 0 && !haveArgumentList)
+      error(rstrprintf("%s expects an argument list", term.to_string().c_str()));
+   if (max == 0 && haveArgumentList)
+      error(rstrprintf("%s does not expect an argument list", term.to_string().c_str()));
+   if (min >= 0 && min == max && (arguments.size() != size_t(min)))
+      error(rstrprintf("%s expects %d arguments, but received %d arguments", term.to_string().c_str(), min, arguments.size()));
+   if (min >= 0 && arguments.size() < size_t(min))
+      error(rstrprintf("%s expects at least %d arguments, but received %d arguments", term.to_string().c_str(), min, arguments.size()));
+   if (max >= 0 && arguments.size() > size_t(max))
+      error(rstrprintf("%s expects at most %d arguments, but received %d arguments", term.to_string().c_str(), max, arguments.size()));
+   return true;
+}
+
+std::unique_ptr<APT::CacheFilter::Matcher> PatternParser::aPattern(std::unique_ptr<PatternTreeParser::Node> &nodeP)
+{
+   assert(nodeP != nullptr);
+   auto node = dynamic_cast<PatternTreeParser::PatternNode *>(nodeP.get());
+   if (node == nullptr)
+      nodeP->error("Expected a pattern");
+
+   if (node->matches("?architecture", 1, 1))
+      return std::make_unique<APT::CacheFilter::PackageArchitectureMatchesSpecification>(aWord(node->arguments[0]));
+   if (node->matches("?archive", 1, 1))
+      return std::make_unique<Patterns::VersionIsArchive>(aWord(node->arguments[0]));
+   if (node->matches("?codename", 1, 1))
+      return std::make_unique<Patterns::VersionIsCodename>(aWord(node->arguments[0]));
+   if (node->matches("?all-versions", 1, 1))
+      return std::make_unique<Patterns::VersionIsAllVersions>(aPattern(node->arguments[0]));
+   if (node->matches("?any-version", 1, 1))
+      return std::make_unique<Patterns::VersionIsAnyVersion>(aPattern(node->arguments[0]));
+   if (node->matches("?automatic", 0, 0))
+      return std::make_unique<Patterns::PackageIsAutomatic>(file);
+   if (node->matches("?broken", 0, 0))
+      return std::make_unique<Patterns::PackageIsBroken>(file);
+   if (node->matches("?config-files", 0, 0))
+      return std::make_unique<Patterns::PackageIsConfigFiles>();
+   if (node->matches("?depends", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]));
+   if (node->matches("?predepends", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::PreDepends);
+   if (node->matches("?suggests", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Suggests);
+   if (node->matches("?recommends", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Recommends);
+   if (node->matches("?conflicts", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Conflicts);
+   if (node->matches("?replaces", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Replaces);
+   if (node->matches("?obsoletes", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Obsoletes);
+   if (node->matches("?breaks", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::DpkgBreaks);
+   if (node->matches("?enhances", 1, 1))
+      return std::make_unique<Patterns::VersionDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Enhances);
+   if (node->matches("?reverse-depends", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]));
+   if (node->matches("?reverse-predepends", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::PreDepends);
+   if (node->matches("?reverse-suggests", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Suggests);
+   if (node->matches("?reverse-recommends", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Recommends);
+   if (node->matches("?reverse-conflicts", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Conflicts);
+   if (node->matches("?reverse-replaces", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Replaces);
+   if (node->matches("?reverse-obsoletes", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Obsoletes);
+   if (node->matches("?reverse-breaks", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::DpkgBreaks);
+   if (node->matches("?reverse-enhances", 1, 1))
+      return std::make_unique<Patterns::PackageReverseDepends>(aPattern(node->arguments[0]), pkgCache::Dep::Enhances);
+   if (node->matches("?essential", 0, 0))
+      return std::make_unique<Patterns::PackageIsEssential>();
+   if (node->matches("?priority", 1, 1))
+      return std::make_unique<Patterns::VersionIsPriority>(aWord(node->arguments[0]));
+   if (node->matches("?exact-name", 1, 1))
+      return std::make_unique<Patterns::PackageHasExactName>(aWord(node->arguments[0]));
+   if (node->matches("?false", 0, 0))
+      return std::make_unique<APT::CacheFilter::FalseMatcher>();
+   if (node->matches("?garbage", 0, 0))
+      return std::make_unique<Patterns::PackageIsGarbage>(file);
+   if (node->matches("?installed", 0, 0))
+      return std::make_unique<Patterns::PackageIsInstalled>(file);
+   if (node->matches("?name", 1, 1))
+      return std::make_unique<APT::CacheFilter::PackageNameMatchesRegEx>(aWord(node->arguments[0]));
+   if (node->matches("?not", 1, 1))
+      return std::make_unique<APT::CacheFilter::NOTMatcher>(aPattern(node->arguments[0]).release());
+   if (node->matches("?obsolete", 0, 0))
+      return std::make_unique<Patterns::PackageIsObsolete>();
+   if (node->matches("?origin", 1, 1))
+      return std::make_unique<Patterns::VersionIsOrigin>(aWord(node->arguments[0]));
+   if (node->matches("?section", 1, 1))
+      return std::make_unique<Patterns::VersionIsSection>(aWord(node->arguments[0]));
+   if (node->matches("?source-package", 1, 1))
+      return std::make_unique<Patterns::VersionIsSourcePackage>(aWord(node->arguments[0]));
+   if (node->matches("?source-version", 1, 1))
+      return std::make_unique<Patterns::VersionIsSourceVersion>(aWord(node->arguments[0]));
+   if (node->matches("?true", 0, 0))
+      return std::make_unique<APT::CacheFilter::TrueMatcher>();
+   if (node->matches("?upgradable", 0, 0))
+      return std::make_unique<Patterns::PackageIsUpgradable>(file);
+   if (node->matches("?version", 1, 1))
+      return std::make_unique<Patterns::VersionIsVersion>(aWord(node->arguments[0]));
+   if (node->matches("?virtual", 0, 0))
+      return std::make_unique<Patterns::PackageIsVirtual>();
+   if (node->matches("?x-name-fnmatch", 1, 1))
+      return std::make_unique<APT::CacheFilter::PackageNameMatchesFnmatch>(aWord(node->arguments[0]));
+
+   // Variable argument patterns
+   if (node->matches("?and", 0, -1) || node->matches("?narrow", 0, -1))
+   {
+      auto pattern = std::make_unique<APT::CacheFilter::ANDMatcher>();
+      for (auto &arg : node->arguments)
+	 pattern->AND(aPattern(arg).release());
+      if (node->term == "?narrow")
+	 return std::make_unique<Patterns::VersionIsAnyVersion>(std::move(pattern));
+      return pattern;
+   }
+   if (node->matches("?or", 0, -1))
+   {
+      auto pattern = std::make_unique<APT::CacheFilter::ORMatcher>();
+
+      for (auto &arg : node->arguments)
+	 pattern->OR(aPattern(arg).release());
+      return pattern;
+   }
+
+   node->error(rstrprintf("Unrecognized pattern '%s'", node->term.to_string().c_str()));
+
+   return nullptr;
+}
+
+std::string PatternParser::aWord(std::unique_ptr<PatternTreeParser::Node> &nodeP)
+{
+   assert(nodeP != nullptr);
+   auto node = dynamic_cast<PatternTreeParser::WordNode *>(nodeP.get());
+   if (node == nullptr)
+      nodeP->error("Expected a word");
+   return node->word.to_string();
+}
+
+namespace Patterns
+{
+
+BaseRegexMatcher::BaseRegexMatcher(std::string const &Pattern)
+{
+   pattern = new regex_t;
+   int const Res = regcomp(pattern, Pattern.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB);
+   if (Res == 0)
+      return;
+
+   delete pattern;
+   pattern = NULL;
+   char Error[300];
+   regerror(Res, pattern, Error, sizeof(Error));
+   _error->Error(_("Regex compilation error - %s"), Error);
+}
+bool BaseRegexMatcher::operator()(const char *string)
+{
+   if (unlikely(pattern == nullptr) || string == nullptr)
+      return false;
+   else
+      return regexec(pattern, string, 0, 0, 0) == 0;
+}
+BaseRegexMatcher::~BaseRegexMatcher()
+{
+   if (pattern == NULL)
+      return;
+   regfree(pattern);
+   delete pattern;
+}
+} // namespace Patterns
+
+} // namespace Internal
+
+// The bridge into the public world
+std::unique_ptr<APT::CacheFilter::Matcher> APT::CacheFilter::ParsePattern(APT::StringView pattern, pkgCacheFile *file)
+{
+   if (file != nullptr && !file->BuildDepCache())
+      return nullptr;
+
+   try
+   {
+      auto top = APT::Internal::PatternTreeParser(pattern).parseTop();
+      APT::Internal::PatternParser parser{file};
+      return parser.aPattern(top);
+   }
+   catch (APT::Internal::PatternTreeParser::Error &e)
+   {
+      std::stringstream ss;
+      ss << "input:" << e.location.start << "-" << e.location.end << ": error: " << e.message << "\n";
+      ss << pattern.to_string() << "\n";
+      for (size_t i = 0; i < e.location.start; i++)
+	 ss << " ";
+      for (size_t i = e.location.start; i < e.location.end; i++)
+	 ss << "^";
+
+      ss << "\n";
+
+      _error->Error("%s", ss.str().c_str());
+      return nullptr;
+   }
+}
+
+} // namespace APT
diff --git a/apt-pkg/cachefilter-patterns.h b/apt-pkg/cachefilter-patterns.h
new file mode 100644
index 0000000..2d48a1c
--- /dev/null
+++ b/apt-pkg/cachefilter-patterns.h
@@ -0,0 +1,456 @@
+/*
+ * cachefilter-patterns.h - Pattern parser and additional patterns as matchers
+ *
+ * Copyright (c) 2019 Canonical Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef APT_CACHEFILTER_PATTERNS_H
+#define APT_CACHEFILTER_PATTERNS_H
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/header-is-private.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <assert.h>
+
+namespace APT
+{
+
+namespace Internal
+{
+/**
+ * \brief PatternTreeParser parses the given sentence into a parse tree.
+ *
+ * The parse tree consists of nodes:
+ *  - Word nodes which contains words or quoted words
+ *  - Patterns, which represent ?foo and ?foo(...) patterns
+ */
+struct APT_PUBLIC PatternTreeParser
+{
+
+   struct Node
+   {
+      size_t start = 0;
+      size_t end = 0;
+
+      explicit Node(size_t start = 0, size_t end = 0) : start(start), end(end) {}
+
+      virtual std::ostream &render(std::ostream &os) { return os; };
+      std::nullptr_t error(std::string message);
+      virtual ~Node() = default;
+   };
+
+   struct Error : public std::exception
+   {
+      Node location;
+      std::string message;
+
+      Error(Node location, std::string message) : location(location), message(message) {}
+      const char *what() const throw() override { return message.c_str(); }
+   };
+
+   struct PatternNode : public Node
+   {
+      APT::StringView term;
+      std::vector<std::unique_ptr<Node>> arguments;
+      bool haveArgumentList = false;
+
+      APT_HIDDEN std::ostream &render(std::ostream &stream) override;
+      APT_HIDDEN bool matches(APT::StringView name, int min, int max);
+   };
+
+   struct WordNode : public Node
+   {
+      APT::StringView word;
+      bool quoted = false;
+      APT_HIDDEN std::ostream &render(std::ostream &stream) override;
+   };
+
+   struct State
+   {
+      size_t offset = 0;
+   };
+
+   APT::StringView sentence;
+   State state;
+
+   PatternTreeParser(APT::StringView sentence) : sentence(sentence){};
+   off_t skipSpace()
+   {
+      while (sentence[state.offset] == ' ' || sentence[state.offset] == '\t' || sentence[state.offset] == '\r' || sentence[state.offset] == '\n')
+	 state.offset++;
+      return state.offset;
+   };
+
+   /// \brief Parse a complete pattern
+   ///
+   /// There may not be anything before or after the pattern, except for
+   /// whitespace.
+   std::unique_ptr<Node> parseTop();
+   std::unique_ptr<Node> parse(); // public for test cases only
+
+   private:
+   APT_HIDDEN std::unique_ptr<Node> parseOr();
+   APT_HIDDEN std::unique_ptr<Node> parseAnd();
+   APT_HIDDEN std::unique_ptr<Node> parseUnary();
+   APT_HIDDEN std::unique_ptr<Node> parsePrimary();
+   APT_HIDDEN std::unique_ptr<Node> parseGroup();
+   APT_HIDDEN std::unique_ptr<Node> parsePattern();
+   APT_HIDDEN std::unique_ptr<Node> parseShortPattern();
+   APT_HIDDEN std::unique_ptr<Node> parseArgument(bool shrt);
+   APT_HIDDEN std::unique_ptr<Node> parseWord(bool shrt);
+   APT_HIDDEN std::unique_ptr<Node> parseQuotedWord();
+};
+
+/**
+ * \brief PatternParser parses the given sentence into a parse tree.
+ *
+ * The parse tree consists of nodes:
+ *  - Word nodes which contains words or quoted words
+ *  - Patterns, which represent ?foo and ?foo(...) patterns
+ */
+struct APT_HIDDEN PatternParser
+{
+   pkgCacheFile *file;
+
+   std::unique_ptr<APT::CacheFilter::Matcher> aPattern(std::unique_ptr<PatternTreeParser::Node> &nodeP);
+   std::string aWord(std::unique_ptr<PatternTreeParser::Node> &nodeP);
+};
+
+namespace Patterns
+{
+using namespace APT::CacheFilter;
+
+/** \brief Basic helper class for matching regex */
+class BaseRegexMatcher
+{
+   regex_t *pattern;
+
+   public:
+   BaseRegexMatcher(std::string const &string);
+   ~BaseRegexMatcher();
+   bool operator()(const char *cstring);
+   bool operator()(std::string const &string)
+   {
+      return (*this)(string.c_str());
+   }
+};
+
+struct APT_HIDDEN PackageIsAutomatic : public PackageMatcher
+{
+   pkgCacheFile *Cache;
+   explicit PackageIsAutomatic(pkgCacheFile *Cache) : Cache(Cache) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      assert(Cache != nullptr);
+      return ((*Cache)[Pkg].Flags & pkgCache::Flag::Auto) != 0;
+   }
+};
+
+struct APT_HIDDEN PackageIsBroken : public PackageMatcher
+{
+   pkgCacheFile *Cache;
+   explicit PackageIsBroken(pkgCacheFile *Cache) : Cache(Cache) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      assert(Cache != nullptr);
+      auto state = (*Cache)[Pkg];
+      return state.InstBroken() || state.NowBroken();
+   }
+};
+
+struct APT_HIDDEN PackageIsConfigFiles : public PackageMatcher
+{
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      return Pkg->CurrentState == pkgCache::State::ConfigFiles;
+   }
+};
+
+struct APT_HIDDEN PackageIsGarbage : public PackageMatcher
+{
+   pkgCacheFile *Cache;
+   explicit PackageIsGarbage(pkgCacheFile *Cache) : Cache(Cache) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      assert(Cache != nullptr);
+      return (*Cache)[Pkg].Garbage;
+   }
+};
+struct APT_HIDDEN PackageIsEssential : public PackageMatcher
+{
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      return (Pkg->Flags & pkgCache::Flag::Essential) != 0;
+   }
+};
+
+struct APT_HIDDEN PackageHasExactName : public PackageMatcher
+{
+   std::string name;
+   explicit PackageHasExactName(std::string name) : name(name) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      return Pkg.Name() == name;
+   }
+};
+
+struct APT_HIDDEN PackageIsInstalled : public PackageMatcher
+{
+   pkgCacheFile *Cache;
+   explicit PackageIsInstalled(pkgCacheFile *Cache) : Cache(Cache) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      assert(Cache != nullptr);
+      return Pkg->CurrentVer != 0;
+   }
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      assert(Cache != nullptr);
+      return Ver == Ver.ParentPkg().CurrentVer();
+   }
+};
+
+struct APT_HIDDEN PackageIsObsolete : public PackageMatcher
+{
+   bool operator()(pkgCache::PkgIterator const &pkg) override
+   {
+      // This code can be written without loops, as aptitude does, but it
+      // is far less readable.
+      if (pkg.CurrentVer().end())
+	 return false;
+
+      // See if there is any version that exists in a repository,
+      // if so return false
+      for (auto ver = pkg.VersionList(); !ver.end(); ver++)
+      {
+	 for (auto file = ver.FileList(); !file.end(); file++)
+	 {
+	    if ((file.File()->Flags & pkgCache::Flag::NotSource) == 0)
+	       return false;
+	 }
+      }
+
+      return true;
+   }
+};
+
+struct APT_HIDDEN PackageIsUpgradable : public PackageMatcher
+{
+   pkgCacheFile *Cache;
+   explicit PackageIsUpgradable(pkgCacheFile *Cache) : Cache(Cache) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      assert(Cache != nullptr);
+      return Pkg->CurrentVer != 0 && (*Cache)[Pkg].Upgradable();
+   }
+};
+
+struct APT_HIDDEN PackageIsVirtual : public PackageMatcher
+{
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      return Pkg->VersionList == 0;
+   }
+};
+
+struct APT_HIDDEN VersionAnyMatcher : public Matcher
+{
+   bool operator()(pkgCache::GrpIterator const &) override { return false; }
+   bool operator()(pkgCache::VerIterator const &Ver) override = 0;
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      for (auto Ver = Pkg.VersionList(); not Ver.end(); Ver++)
+      {
+         if ((*this)(Ver))
+            return true;
+      }
+      return false;
+   }
+};
+
+struct APT_HIDDEN VersionIsAllVersions : public Matcher
+{
+   std::unique_ptr<APT::CacheFilter::Matcher> base;
+   VersionIsAllVersions(std::unique_ptr<APT::CacheFilter::Matcher> base) : base(std::move(base)) {}
+   bool operator()(pkgCache::GrpIterator const &) override { return false; }
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return (*base)(Ver);
+   }
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      for (auto Ver = Pkg.VersionList(); not Ver.end(); Ver++)
+      {
+	 if (not(*this)(Ver))
+	    return false;
+      }
+      return true;
+   }
+};
+
+struct APT_HIDDEN VersionDepends : public VersionAnyMatcher
+{
+   std::unique_ptr<APT::CacheFilter::Matcher> base;
+   pkgCache::Dep::DepType type;
+   VersionDepends(std::unique_ptr<APT::CacheFilter::Matcher> base, pkgCache::Dep::DepType type = pkgCache::Dep::Depends) : base(std::move(base)), type(type) {}
+   bool operator()(pkgCache::GrpIterator const &) override { return false; }
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      for (auto D = Ver.DependsList(); not D.end(); D++)
+      {
+	 if (D.IsImplicit())
+	    continue;
+	 if (D->Type != type)
+	    continue;
+	 if ((*base)(D.TargetPkg()))
+	    return true;
+      }
+
+      return false;
+   }
+};
+
+struct APT_HIDDEN PackageReverseDepends : public PackageMatcher
+{
+   std::unique_ptr<APT::CacheFilter::Matcher> base;
+   pkgCache::Dep::DepType type;
+   PackageReverseDepends(std::unique_ptr<APT::CacheFilter::Matcher> base, pkgCache::Dep::DepType type = pkgCache::Dep::Depends) : base(std::move(base)), type(type) {}
+   bool operator()(pkgCache::PkgIterator const &Pkg) override
+   {
+      for (auto D = Pkg.RevDependsList(); not D.end(); D++)
+      {
+	 if (D.IsImplicit())
+	    continue;
+	 if (D->Type != type)
+	    continue;
+	 if ((*base)(D.ParentVer()))
+	    return true;
+      }
+
+      return false;
+   }
+};
+
+struct APT_HIDDEN VersionIsAnyVersion : public VersionAnyMatcher
+{
+   std::unique_ptr<APT::CacheFilter::Matcher> base;
+   VersionIsAnyVersion(std::unique_ptr<APT::CacheFilter::Matcher> base) : base(std::move(base)) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return (*base)(Ver);
+   }
+};
+
+struct APT_HIDDEN VersionIsArchive : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsArchive(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      for (auto VF = Ver.FileList(); not VF.end(); VF++)
+      {
+	 if (VF.File().Archive() && matcher(VF.File().Archive()))
+	    return true;
+      }
+      return false;
+   }
+};
+
+struct APT_HIDDEN VersionIsCodename : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsCodename(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      for (auto VF = Ver.FileList(); not VF.end(); VF++)
+      {
+	 if (VF.File().Codename() && matcher(VF.File().Codename()))
+	    return true;
+      }
+      return false;
+   }
+};
+
+struct APT_HIDDEN VersionIsOrigin : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsOrigin(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      for (auto VF = Ver.FileList(); not VF.end(); VF++)
+      {
+	 if (VF.File().Origin() && matcher(VF.File().Origin()))
+	    return true;
+      }
+      return false;
+   }
+};
+
+struct APT_HIDDEN VersionIsSection : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsSection(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return matcher(Ver.Section());
+   }
+};
+
+struct APT_HIDDEN VersionIsSourcePackage : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsSourcePackage(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return matcher(Ver.SourcePkgName());
+   }
+};
+
+struct APT_HIDDEN VersionIsSourceVersion : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsSourceVersion(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return matcher(Ver.SourceVerStr());
+   }
+};
+
+struct APT_HIDDEN VersionIsVersion : public VersionAnyMatcher
+{
+   BaseRegexMatcher matcher;
+   VersionIsVersion(std::string const &pattern) : matcher(pattern) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      return matcher(Ver.VerStr());
+   }
+};
+
+struct APT_HIDDEN VersionIsPriority : public VersionAnyMatcher
+{
+   std::string name;
+   explicit VersionIsPriority(std::string name) : name(name) {}
+   bool operator()(pkgCache::VerIterator const &Ver) override
+   {
+      std::string Mapping[] = {"", "required","important","standard",
+                            "optional","extra"};
+      if (Ver->Priority > 0 && Ver->Priority < APT_ARRAY_SIZE(Mapping)) {
+         return name == Mapping[Ver->Priority];
+      }
+      return false;
+   }
+};
+
+} // namespace Patterns
+} // namespace Internal
+} // namespace APT
+#endif
diff --git a/apt-pkg/cachefilter.cc b/apt-pkg/cachefilter.cc
new file mode 100644
index 0000000..eadbb98
--- /dev/null
+++ b/apt-pkg/cachefilter.cc
@@ -0,0 +1,264 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/** \file cachefilter.h
+    Collection of functor classes */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <string>
+#include <unordered_map>
+#include <fnmatch.h>
+#include <regex.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+namespace APT {
+
+APT_HIDDEN std::unordered_map<std::string, std::vector<std::string>> ArchToTupleMap;
+
+namespace CacheFilter {
+Matcher::~Matcher() {}
+PackageMatcher::~PackageMatcher() {}
+
+// Name matches RegEx							/*{{{*/
+PackageNameMatchesRegEx::PackageNameMatchesRegEx(std::string const &Pattern) {
+	pattern = new regex_t;
+	int const Res = regcomp(pattern, Pattern.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB);
+	if (Res == 0)
+		return;
+
+	delete pattern;
+	pattern = NULL;
+	char Error[300];
+	regerror(Res, pattern, Error, sizeof(Error));
+	_error->Error(_("Regex compilation error - %s"), Error);
+}
+bool PackageNameMatchesRegEx::operator() (pkgCache::PkgIterator const &Pkg) {
+	if (unlikely(pattern == NULL))
+		return false;
+	else
+		return regexec(pattern, Pkg.Name(), 0, 0, 0) == 0;
+}
+bool PackageNameMatchesRegEx::operator() (pkgCache::GrpIterator const &Grp) {
+	if (unlikely(pattern == NULL))
+		return false;
+	else
+		return regexec(pattern, Grp.Name(), 0, 0, 0) == 0;
+}
+PackageNameMatchesRegEx::~PackageNameMatchesRegEx() {
+	if (pattern == NULL)
+		return;
+	regfree(pattern);
+	delete pattern;
+}
+									/*}}}*/
+// Name matches Fnmatch							/*{{{*/
+PackageNameMatchesFnmatch::PackageNameMatchesFnmatch(std::string const &Pattern) :
+   Pattern(Pattern) {}
+bool PackageNameMatchesFnmatch::operator() (pkgCache::PkgIterator const &Pkg) {
+   return fnmatch(Pattern.c_str(), Pkg.Name(), FNM_CASEFOLD) == 0;
+}
+bool PackageNameMatchesFnmatch::operator() (pkgCache::GrpIterator const &Grp) {
+   return fnmatch(Pattern.c_str(), Grp.Name(), FNM_CASEFOLD) == 0;
+}
+									/*}}}*/
+// Architecture matches <abi>-<libc>-<kernel>-<cpu> specification	/*{{{*/
+//----------------------------------------------------------------------
+
+static std::vector<std::string> ArchToTuple(std::string arch) {
+   // Strip leading linux- from arch if present
+   // dpkg says this may disappear in the future
+   if (APT::String::Startswith(arch, std::string("linux-")))
+      arch = arch.substr(6);
+
+   auto it = ArchToTupleMap.find(arch);
+   if (it != ArchToTupleMap.end())
+   {
+      std::vector<std::string> result = it->second;
+      // Hack in support for triplets
+      if (result.size() == 3)
+	 result.emplace(result.begin(), "base");
+      return result;
+   } else
+   {
+      return {};
+   }
+}
+
+static std::vector<std::string> PatternToTuple(std::string const &arch) {
+   std::vector<std::string> tuple = VectorizeString(arch, '-');
+   if (std::find(tuple.begin(), tuple.end(), std::string("any")) != tuple.end() ||
+       std::find(arch.begin(), arch.end(), '*') != arch.end()) {
+      while (tuple.size() < 4) {
+	 tuple.emplace(tuple.begin(), "any");
+      }
+      return tuple;
+   } else
+      return ArchToTuple(arch);
+}
+
+/* The complete architecture, consisting of <abi>-<libc>-<kernel>-<cpu>. */
+static std::string CompleteArch(std::string const &arch, bool const isPattern) {
+   auto tuple = isPattern ? PatternToTuple(arch) : ArchToTuple(arch);
+
+   // Bah, the commandline will try and pass us stuff like amd64- -- we need
+   // that not to match an architecture, but the code below would turn it into
+   // a valid tuple. Let's just use an invalid tuple here.
+   if (APT::String::Endswith(arch, "-") || APT::String::Startswith(arch, "-"))
+      return "invalid-invalid-invalid-invalid";
+
+   if (tuple.empty()) {
+      // Fallback for unknown architectures
+      // Patterns never fail if they contain wildcards, so by this point, arch
+      // has no wildcards.
+      tuple = VectorizeString(arch, '-');
+      switch (tuple.size()) {
+	 case 1:
+	    tuple.emplace(tuple.begin(), "linux");
+	    /* fall through */
+	 case 2:
+	    tuple.emplace(tuple.begin(), "gnu");
+	    /* fall through */
+	 case 3:
+	    tuple.emplace(tuple.begin(), "base");
+	    /* fall through */
+	    break;
+      }
+   }
+
+   std::replace(tuple.begin(), tuple.end(), std::string("any"), std::string("*"));
+   return APT::String::Join(tuple, "-");
+}
+PackageArchitectureMatchesSpecification::PackageArchitectureMatchesSpecification(std::string const &pattern, bool const pisPattern) :
+					literal(pattern), complete(CompleteArch(pattern, pisPattern)), isPattern(pisPattern) {
+}
+bool PackageArchitectureMatchesSpecification::operator() (char const * const &arch) {
+	if (strcmp(literal.c_str(), arch) == 0 ||
+	    strcmp(complete.c_str(), arch) == 0)
+		return true;
+	std::string const pkgarch = CompleteArch(arch, !isPattern);
+	if (isPattern == true)
+		return fnmatch(complete.c_str(), pkgarch.c_str(), 0) == 0;
+	return fnmatch(pkgarch.c_str(), complete.c_str(), 0) == 0;
+}
+bool PackageArchitectureMatchesSpecification::operator() (pkgCache::PkgIterator const &Pkg) {
+	return (*this)(Pkg.Arch());
+}
+PackageArchitectureMatchesSpecification::~PackageArchitectureMatchesSpecification() {
+}
+									/*}}}*/
+// Package is new install						/*{{{*/
+PackageIsNewInstall::PackageIsNewInstall(pkgCacheFile * const Cache) : Cache(Cache) {}
+APT_PURE bool PackageIsNewInstall::operator() (pkgCache::PkgIterator const &Pkg) {
+   return (*Cache)[Pkg].NewInstall();
+}
+PackageIsNewInstall::~PackageIsNewInstall() {}
+									/*}}}*/
+// Generica like True, False, NOT, AND, OR				/*{{{*/
+APT_PURE bool TrueMatcher::operator() (pkgCache::PkgIterator const &) { return true; }
+APT_PURE bool TrueMatcher::operator() (pkgCache::GrpIterator const &) { return true; }
+APT_PURE bool TrueMatcher::operator() (pkgCache::VerIterator const &) { return true; }
+
+APT_PURE bool FalseMatcher::operator() (pkgCache::PkgIterator const &) { return false; }
+APT_PURE bool FalseMatcher::operator() (pkgCache::GrpIterator const &) { return false; }
+APT_PURE bool FalseMatcher::operator() (pkgCache::VerIterator const &) { return false; }
+
+NOTMatcher::NOTMatcher(Matcher * const matcher) : matcher(matcher) {}
+bool NOTMatcher::operator() (pkgCache::PkgIterator const &Pkg) { return ! (*matcher)(Pkg); }
+bool NOTMatcher::operator() (pkgCache::GrpIterator const &Grp) { return ! (*matcher)(Grp); }
+bool NOTMatcher::operator() (pkgCache::VerIterator const &Ver) { return ! (*matcher)(Ver); }
+NOTMatcher::~NOTMatcher() { delete matcher; }
+
+ANDMatcher::ANDMatcher() {}
+ANDMatcher::ANDMatcher(Matcher * const matcher1) {
+   AND(matcher1);
+}
+ANDMatcher::ANDMatcher(Matcher * const matcher1, Matcher * const matcher2) {
+   AND(matcher1).AND(matcher2);
+}
+ANDMatcher::ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3) {
+   AND(matcher1).AND(matcher2).AND(matcher3);
+}
+ANDMatcher::ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4) {
+   AND(matcher1).AND(matcher2).AND(matcher3).AND(matcher4);
+}
+ANDMatcher::ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4, Matcher * const matcher5) {
+   AND(matcher1).AND(matcher2).AND(matcher3).AND(matcher4).AND(matcher5);
+}
+ANDMatcher& ANDMatcher::AND(Matcher * const matcher) { matchers.push_back(matcher); return *this; }
+bool ANDMatcher::operator() (pkgCache::PkgIterator const &Pkg) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Pkg) == false)
+	 return false;
+   return true;
+}
+bool ANDMatcher::operator() (pkgCache::GrpIterator const &Grp) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Grp) == false)
+	 return false;
+   return true;
+}
+bool ANDMatcher::operator() (pkgCache::VerIterator const &Ver) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Ver) == false)
+	 return false;
+   return true;
+}
+ANDMatcher::~ANDMatcher() {
+   for (std::vector<Matcher *>::iterator M = matchers.begin(); M != matchers.end(); ++M)
+      delete *M;
+}
+
+ORMatcher::ORMatcher() {}
+ORMatcher::ORMatcher(Matcher * const matcher1) {
+   OR(matcher1);
+}
+ORMatcher::ORMatcher(Matcher * const matcher1, Matcher * const matcher2) {
+   OR(matcher1).OR(matcher2);
+}
+ORMatcher::ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3) {
+   OR(matcher1).OR(matcher2).OR(matcher3);
+}
+ORMatcher::ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4) {
+   OR(matcher1).OR(matcher2).OR(matcher3).OR(matcher4);
+}
+ORMatcher::ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4, Matcher * const matcher5) {
+   OR(matcher1).OR(matcher2).OR(matcher3).OR(matcher4).OR(matcher5);
+}
+ORMatcher& ORMatcher::OR(Matcher * const matcher) { matchers.push_back(matcher); return *this; }
+bool ORMatcher::operator() (pkgCache::PkgIterator const &Pkg) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Pkg) == true)
+	 return true;
+   return false;
+}
+bool ORMatcher::operator() (pkgCache::GrpIterator const &Grp) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Grp) == true)
+	 return true;
+   return false;
+}
+bool ORMatcher::operator() (pkgCache::VerIterator const &Ver) {
+   for (std::vector<Matcher *>::const_iterator M = matchers.begin(); M != matchers.end(); ++M)
+      if ((**M)(Ver) == true)
+	 return true;
+   return false;
+}
+ORMatcher::~ORMatcher() {
+   for (std::vector<Matcher *>::iterator M = matchers.begin(); M != matchers.end(); ++M)
+      delete *M;
+}
+									/*}}}*/
+
+}
+}
diff --git a/apt-pkg/cachefilter.h b/apt-pkg/cachefilter.h
new file mode 100644
index 0000000..1b5f9aa
--- /dev/null
+++ b/apt-pkg/cachefilter.h
@@ -0,0 +1,156 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/** \file cachefilter.h
+   Collection of functor classes */
+									/*}}}*/
+#ifndef APT_CACHEFILTER_H
+#define APT_CACHEFILTER_H
+// Include Files							/*{{{*/
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/string_view.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <regex.h>
+
+class pkgCacheFile;
+									/*}}}*/
+namespace APT {
+namespace CacheFilter {
+
+class APT_PUBLIC Matcher {
+public:
+   virtual bool operator() (pkgCache::PkgIterator const &/*Pkg*/) = 0;
+   virtual bool operator() (pkgCache::GrpIterator const &/*Grp*/) = 0;
+   virtual bool operator() (pkgCache::VerIterator const &/*Ver*/) = 0;
+   virtual ~Matcher();
+};
+
+class APT_PUBLIC PackageMatcher : public Matcher {
+public:
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE = 0;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE { return (*this)(Ver.ParentPkg()); }
+   bool operator() (pkgCache::GrpIterator const &/*Grp*/) APT_OVERRIDE { return false; }
+   ~PackageMatcher() APT_OVERRIDE;
+};
+
+// Generica like True, False, NOT, AND, OR				/*{{{*/
+class APT_PUBLIC TrueMatcher : public Matcher {
+public:
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+};
+
+class APT_PUBLIC FalseMatcher : public Matcher {
+public:
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+};
+
+class APT_PUBLIC NOTMatcher : public Matcher {
+   Matcher * const matcher;
+public:
+   explicit NOTMatcher(Matcher * const matcher);
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+   ~NOTMatcher() APT_OVERRIDE;
+};
+
+class APT_PUBLIC ANDMatcher : public Matcher {
+   std::vector<Matcher *> matchers;
+public:
+   // 5 ought to be enough for everybody… c++11 variadic templates would be nice
+   ANDMatcher();
+   explicit ANDMatcher(Matcher * const matcher1);
+   ANDMatcher(Matcher * const matcher1, Matcher * const matcher2);
+   ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3);
+   ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4);
+   ANDMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4, Matcher * const matcher5);
+   ANDMatcher& AND(Matcher * const matcher);
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+   ~ANDMatcher() APT_OVERRIDE;
+};
+class APT_PUBLIC ORMatcher : public Matcher {
+   std::vector<Matcher *> matchers;
+public:
+   // 5 ought to be enough for everybody… c++11 variadic templates would be nice
+   ORMatcher();
+   explicit ORMatcher(Matcher * const matcher1);
+   ORMatcher(Matcher * const matcher1, Matcher * const matcher2);
+   ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3);
+   ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4);
+   ORMatcher(Matcher * const matcher1, Matcher * const matcher2, Matcher * const matcher3, Matcher * const matcher4, Matcher * const matcher5);
+   ORMatcher& OR(Matcher * const matcher);
+   bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+   bool operator() (pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+   ~ORMatcher() APT_OVERRIDE;
+};
+									/*}}}*/
+class APT_PUBLIC PackageNameMatchesRegEx : public PackageMatcher {			/*{{{*/
+	regex_t* pattern;
+public:
+	explicit PackageNameMatchesRegEx(std::string const &Pattern);
+	bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+	bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+	~PackageNameMatchesRegEx() APT_OVERRIDE;
+};
+									/*}}}*/
+class APT_PUBLIC PackageNameMatchesFnmatch : public PackageMatcher {		/*{{{*/
+	const std::string Pattern;
+public:
+	explicit PackageNameMatchesFnmatch(std::string const &Pattern);
+	bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+	bool operator() (pkgCache::GrpIterator const &Grp) APT_OVERRIDE;
+	~PackageNameMatchesFnmatch() APT_OVERRIDE = default;
+};
+									/*}}}*/
+class APT_PUBLIC PackageArchitectureMatchesSpecification : public PackageMatcher {	/*{{{*/
+/** \class PackageArchitectureMatchesSpecification
+   \brief matching against architecture specification strings
+
+   The strings are of the format <libc>-<kernel>-<cpu> where either component,
+   or the whole string, can be the wildcard "any" as defined in
+   debian-policy §11.1 "Architecture specification strings".
+
+   Examples: i386, mipsel, musl-linux-amd64, linux-any, any-amd64, any */
+	std::string literal;
+	std::string complete;
+	bool isPattern;
+public:
+	/** \brief matching against architecture specification strings
+	 *
+	 * @param pattern is the architecture specification string
+	 * @param isPattern defines if the given \b pattern is a
+	 *        architecture specification pattern to match others against
+	 *        or if it is the fixed string and matched against patterns
+	 */
+	PackageArchitectureMatchesSpecification(std::string const &pattern, bool const isPattern = true);
+	bool operator() (char const * const &arch);
+	using PackageMatcher::operator();
+	bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+	~PackageArchitectureMatchesSpecification() APT_OVERRIDE;
+};
+									/*}}}*/
+class APT_PUBLIC PackageIsNewInstall : public PackageMatcher {			/*{{{*/
+	pkgCacheFile * const Cache;
+public:
+	explicit PackageIsNewInstall(pkgCacheFile * const Cache);
+	using PackageMatcher::operator();
+	bool operator() (pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+	~PackageIsNewInstall() APT_OVERRIDE;
+};
+									/*}}}*/
+
+/// \brief Parse a pattern, return nullptr or pattern
+APT_PUBLIC std::unique_ptr<APT::CacheFilter::Matcher> ParsePattern(APT::StringView pattern, pkgCacheFile *file);
+}
+}
+#endif
diff --git a/apt-pkg/cacheiterators.h b/apt-pkg/cacheiterators.h
new file mode 100644
index 0000000..9273369
--- /dev/null
+++ b/apt-pkg/cacheiterators.h
@@ -0,0 +1,548 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Cache Iterators - Iterators for navigating the cache structure
+   
+   The iterators all provides ++,==,!=,->,* and end for their type.
+   The end function can be used to tell if the list has been fully
+   traversed.
+   
+   Unlike STL iterators these contain helper functions to access the data
+   that is being iterated over. This is because the data structures can't
+   be formed in a manner that is intuitive to use and also mmapable.
+   
+   For each variable in the target structure that would need a translation
+   to be accessed correctly a translating function of the same name is
+   present in the iterator. If applicable the translating function will
+   return an iterator.
+
+   The DepIterator can iterate over two lists, a list of 'version depends'
+   or a list of 'package reverse depends'. The type is determined by the
+   structure passed to the constructor, which should be the structure
+   that has the depends pointer as a member. The provide iterator has the
+   same system.
+   
+   This header is not user includable, please use apt-pkg/pkgcache.h
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CACHEITERATORS_H
+#define PKGLIB_CACHEITERATORS_H
+#ifndef __PKGLIB_IN_PKGCACHE_H
+#warning apt-pkg/cacheiterators.h should not be included directly, include apt-pkg/pkgcache.h instead
+#endif
+#include <apt-pkg/macros.h>
+
+#include <iosfwd>
+#include <iterator>
+#include <string>
+#include <apt-pkg/string_view.h>
+
+#include <string.h>
+
+// abstract Iterator template						/*{{{*/
+/* This template provides the very basic iterator methods we
+   need to have for doing some walk-over-the-cache magic */
+template<typename Str, typename Itr> class APT_PUBLIC pkgCache::Iterator {
+	/** \brief Returns the Pointer for this struct in the owner
+	 *  The implementation of this method should be pretty short
+	 *  as it will only return the Pointer into the mmap stored
+	 *  in the owner but the name of this pointer is different for
+	 *  each structure and we want to abstract here at least for the
+	 *  basic methods from the actual structure.
+	 *  \return Pointer to the first structure of this type
+	 */
+	Str* OwnerPointer() const { return static_cast<Itr const*>(this)->OwnerPointer(); }
+
+	protected:
+	Str *S;
+	pkgCache *Owner;
+
+	public:
+	// iterator_traits
+	using iterator_category = std::forward_iterator_tag;
+	using value_type = Str;
+	using difference_type = std::ptrdiff_t;
+	using pointer = Str*;
+	using reference = Str&;
+	// Iteration
+	inline bool end() const {return Owner == 0 || S == OwnerPointer();}
+
+	// Comparison
+	inline bool operator ==(const Itr &B) const {return S == B.S;}
+	inline bool operator !=(const Itr &B) const {return S != B.S;}
+
+	// Accessors
+	inline Str *operator ->() {return S;}
+	inline Str const *operator ->() const {return S;}
+	inline operator Str *() {return S == OwnerPointer() ? 0 : S;}
+	inline operator Str const *() const {return S == OwnerPointer() ? 0 : S;}
+	inline Str &operator *() {return *S;}
+	inline Str const &operator *() const {return *S;}
+	inline pkgCache *Cache() const {return Owner;}
+
+	// Mixed stuff
+	inline bool IsGood() const { return S && Owner && ! end();}
+	inline unsigned long Index() const {return S - OwnerPointer();}
+	inline map_pointer<Str> MapPointer() const {return map_pointer<Str>(Index()) ;}
+
+	void ReMap(void const * const oldMap, void * const newMap) {
+		if (Owner == 0 || S == 0)
+			return;
+		S = static_cast<Str *>(newMap) + (S - static_cast<Str const *>(oldMap));
+	}
+
+	// Constructors - look out for the variable assigning
+	inline Iterator() : S(0), Owner(0) {}
+	inline Iterator(pkgCache &Owner,Str *T = 0) : S(T), Owner(&Owner) {}
+};
+									/*}}}*/
+// Group Iterator							/*{{{*/
+/* Packages with the same name are collected in a Group so someone only
+   interest in package names can iterate easily over the names, so the
+   different architectures can be treated as of the "same" package
+   (apt internally treat them as totally different packages) */
+class APT_PUBLIC pkgCache::GrpIterator: public Iterator<Group, GrpIterator> {
+	long HashIndex;
+
+	public:
+	inline Group* OwnerPointer() const {
+		return (Owner != 0) ? Owner->GrpP : 0;
+	}
+
+	// This constructor is the 'begin' constructor, never use it.
+	explicit inline GrpIterator(pkgCache &Owner) : Iterator<Group, GrpIterator>(Owner), HashIndex(-1) {
+		S = OwnerPointer();
+		operator++();
+	}
+
+	GrpIterator& operator++();
+	inline GrpIterator operator++(int) { GrpIterator const tmp(*this); operator++(); return tmp; }
+
+	inline const char *Name() const {return S->Name == 0?0:Owner->StrP + S->Name;}
+	inline PkgIterator PackageList() const;
+	inline VerIterator VersionsInSource() const;
+	PkgIterator FindPkg(APT::StringView Arch = APT::StringView("any", 3)) const;
+	/** \brief find the package with the "best" architecture
+
+	    The best architecture is either the "native" or the first
+	    in the list of Architectures which is not an end-Pointer
+
+	    \param PreferNonVirtual tries to respond with a non-virtual package
+		   and only if this fails returns the best virtual package */
+	PkgIterator FindPreferredPkg(bool const &PreferNonVirtual = true) const;
+	PkgIterator NextPkg(PkgIterator const &Pkg) const;
+
+	// Constructors
+	inline GrpIterator(pkgCache &Owner, Group *Trg) : Iterator<Group, GrpIterator>(Owner, Trg), HashIndex(0) {
+		if (S == 0)
+			S = OwnerPointer();
+	}
+	inline GrpIterator() : Iterator<Group, GrpIterator>(), HashIndex(0) {}
+
+};
+									/*}}}*/
+// Package Iterator							/*{{{*/
+class APT_PUBLIC pkgCache::PkgIterator: public Iterator<Package, PkgIterator> {
+	long HashIndex;
+
+	public:
+	inline Package* OwnerPointer() const {
+		return (Owner != 0) ? Owner->PkgP : 0;
+	}
+
+	// This constructor is the 'begin' constructor, never use it.
+	explicit inline PkgIterator(pkgCache &Owner) : Iterator<Package, PkgIterator>(Owner), HashIndex(-1) {
+		S = OwnerPointer();
+		operator++();
+	}
+
+	PkgIterator& operator++();
+	inline PkgIterator operator++(int) { PkgIterator const tmp(*this); operator++(); return tmp; }
+
+	enum OkState {NeedsNothing,NeedsUnpack,NeedsConfigure};
+
+	// Accessors
+	inline const char *Name() const { return Group().Name(); }
+	inline bool Purge() const {return S->CurrentState == pkgCache::State::Purge ||
+		(S->CurrentVer == 0 && S->CurrentState == pkgCache::State::NotInstalled);}
+	inline const char *Arch() const {return S->Arch == 0?0:Owner->StrP + S->Arch;}
+	inline APT_PURE GrpIterator Group() const { return GrpIterator(*Owner, Owner->GrpP + S->Group);}
+
+	inline VerIterator VersionList() const APT_PURE;
+	inline VerIterator CurrentVer() const APT_PURE;
+	inline DepIterator RevDependsList() const APT_PURE;
+	inline PrvIterator ProvidesList() const APT_PURE;
+	OkState State() const APT_PURE;
+	const char *CurVersion() const APT_PURE;
+
+	//Nice printable representation
+	APT_DEPRECATED_MSG("Use APT::PrettyPkg instead") friend std::ostream& operator <<(std::ostream& out, PkgIterator i);
+	std::string FullName(bool const &Pretty = false) const;
+
+	// Constructors
+	inline PkgIterator(pkgCache &Owner,Package *Trg) : Iterator<Package, PkgIterator>(Owner, Trg), HashIndex(0) {
+		if (S == 0)
+			S = OwnerPointer();
+	}
+	inline PkgIterator() : Iterator<Package, PkgIterator>(), HashIndex(0) {}
+};
+									/*}}}*/
+// Version Iterator							/*{{{*/
+class APT_PUBLIC pkgCache::VerIterator : public Iterator<Version, VerIterator> {
+	public:
+	inline Version* OwnerPointer() const {
+		return (Owner != 0) ? Owner->VerP : 0;
+	}
+
+	// Iteration
+	inline VerIterator& operator++() {if (S != Owner->VerP) S = Owner->VerP + S->NextVer; return *this;}
+	inline VerIterator operator++(int) { VerIterator const tmp(*this); operator++(); return tmp; }
+
+	inline VerIterator NextInSource()
+	{
+	   if (S != Owner->VerP)
+	      S = Owner->VerP + S->NextInSource;
+	   return *this;
+	}
+
+	// Comparison
+	int CompareVer(const VerIterator &B) const;
+	/** \brief compares two version and returns if they are similar
+
+	    This method should be used to identify if two pseudo versions are
+	    referring to the same "real" version */
+	inline bool SimilarVer(const VerIterator &B) const {
+		return (B.end() == false && S->Hash == B->Hash && strcmp(VerStr(), B.VerStr()) == 0);
+	}
+
+	// Accessors
+	inline const char *VerStr() const {return S->VerStr == 0?0:Owner->StrP + S->VerStr;}
+	inline const char *Section() const {return S->Section == 0?0:Owner->StrP + S->Section;}
+	/** \brief source package name this version comes from
+	   Always contains the name, even if it is the same as the binary name */
+	inline const char *SourcePkgName() const {return Owner->StrP + S->SourcePkgName;}
+	/** \brief source version this version comes from
+	   Always contains the version string, even if it is the same as the binary version */
+	inline const char *SourceVerStr() const {return Owner->StrP + S->SourceVerStr;}
+	inline const char *Arch() const {
+		if ((S->MultiArch & pkgCache::Version::All) == pkgCache::Version::All)
+			return "all";
+		return S->ParentPkg == 0?0:Owner->StrP + ParentPkg()->Arch;
+	}
+	inline PkgIterator ParentPkg() const {return PkgIterator(*Owner,Owner->PkgP + S->ParentPkg);}
+
+	inline DescIterator DescriptionList() const;
+	DescIterator TranslatedDescriptionForLanguage(APT::StringView lang) const;
+	DescIterator TranslatedDescription() const;
+	inline DepIterator DependsList() const;
+	inline PrvIterator ProvidesList() const;
+	inline VerFileIterator FileList() const;
+	bool Downloadable() const;
+	inline const char *PriorityType() const {return Owner->Priority(S->Priority);}
+	const char *MultiArchType() const APT_PURE;
+	std::string RelStr() const;
+
+	bool Automatic() const;
+	VerFileIterator NewestFile() const;
+
+#ifdef APT_COMPILING_APT
+	inline unsigned int PhasedUpdatePercentage() const
+	{
+	   return (static_cast<Version::Extra *>(Owner->Map.Data()) + S->d)->PhasedUpdatePercentage;
+	}
+	inline bool PhasedUpdatePercentage(unsigned int percentage)
+	{
+	   if (percentage > 100)
+	      return false;
+	   (static_cast<Version::Extra *>(Owner->Map.Data()) + S->d)->PhasedUpdatePercentage = static_cast<uint8_t>(percentage);
+	   return true;
+	}
+#endif
+
+	inline VerIterator(pkgCache &Owner,Version *Trg = 0) : Iterator<Version, VerIterator>(Owner, Trg) {
+		if (S == 0)
+			S = OwnerPointer();
+	}
+	inline VerIterator() : Iterator<Version, VerIterator>() {}
+};
+									/*}}}*/
+// Description Iterator							/*{{{*/
+class APT_PUBLIC pkgCache::DescIterator : public Iterator<Description, DescIterator> {
+	public:
+	inline Description* OwnerPointer() const {
+		return (Owner != 0) ? Owner->DescP : 0;
+	}
+
+	// Iteration
+	inline DescIterator& operator++() {if (S != Owner->DescP) S = Owner->DescP + S->NextDesc; return *this;}
+	inline DescIterator operator++(int) { DescIterator const tmp(*this); operator++(); return tmp; }
+
+	// Comparison
+	int CompareDesc(const DescIterator &B) const;
+
+	// Accessors
+	inline const char *LanguageCode() const {return Owner->StrP + S->language_code;}
+	inline const char *md5() const {return Owner->StrP + S->md5sum;}
+	inline DescFileIterator FileList() const;
+
+	inline DescIterator() : Iterator<Description, DescIterator>() {}
+	inline DescIterator(pkgCache &Owner,Description *Trg = 0) : Iterator<Description, DescIterator>(Owner, Trg) {
+		if (S == 0)
+			S = Owner.DescP;
+	}
+};
+									/*}}}*/
+// Dependency iterator							/*{{{*/
+class APT_PUBLIC pkgCache::DepIterator : public Iterator<Dependency, DepIterator> {
+	enum {DepVer, DepRev} Type;
+	DependencyData * S2;
+
+	public:
+	inline Dependency* OwnerPointer() const {
+		return (Owner != 0) ? Owner->DepP : 0;
+	}
+
+	// Iteration
+	DepIterator& operator++();
+	inline DepIterator operator++(int) { DepIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline const char *TargetVer() const {return S2->Version == 0?0:Owner->StrP + S2->Version;}
+	inline PkgIterator TargetPkg() const {return PkgIterator(*Owner,Owner->PkgP + S2->Package);}
+	inline PkgIterator SmartTargetPkg() const {PkgIterator R(*Owner,0);SmartTargetPkg(R);return R;}
+	inline VerIterator ParentVer() const {return VerIterator(*Owner,Owner->VerP + S->ParentVer);}
+	inline PkgIterator ParentPkg() const {return PkgIterator(*Owner,Owner->PkgP + Owner->VerP[uint32_t(S->ParentVer)].ParentPkg);}
+	inline bool Reverse() const {return Type == DepRev;}
+	bool IsCritical() const APT_PURE;
+	bool IsNegative() const APT_PURE;
+	bool IsIgnorable(PrvIterator const &Prv) const APT_PURE;
+	bool IsIgnorable(PkgIterator const &Pkg) const APT_PURE;
+	/* MultiArch can be translated to SingleArch for an resolver and we did so,
+	   by adding dependencies to help the resolver understand the problem, but
+	   sometimes it is needed to identify these to ignore them… */
+	inline bool IsMultiArchImplicit() const APT_PURE {
+		return (S2->CompareOp & pkgCache::Dep::MultiArchImplicit) == pkgCache::Dep::MultiArchImplicit;
+	}
+	/* This covers additionally negative dependencies, which aren't arch-specific,
+	   but change architecture nonetheless as a Conflicts: foo does applies for all archs */
+	bool IsImplicit() const APT_PURE;
+
+	bool IsSatisfied(VerIterator const &Ver) const APT_PURE;
+	bool IsSatisfied(PrvIterator const &Prv) const APT_PURE;
+	void GlobOr(DepIterator &Start,DepIterator &End);
+	Version **AllTargets() const;
+	bool SmartTargetPkg(PkgIterator &Result) const;
+	inline const char *CompType() const {return Owner->CompType(S2->CompareOp);}
+	inline const char *DepType() const {return Owner->DepType(S2->Type);}
+
+	// overrides because we are special
+	struct DependencyProxy
+	{
+	   map_stringitem_t &Version;
+	   map_pointer<pkgCache::Package> &Package;
+	   map_id_t &ID;
+	   unsigned char &Type;
+	   unsigned char &CompareOp;
+	   map_pointer<pkgCache::Version> &ParentVer;
+	   map_pointer<pkgCache::DependencyData> &DependencyData;
+	   map_pointer<Dependency> &NextRevDepends;
+	   map_pointer<Dependency> &NextDepends;
+	   map_pointer<pkgCache::DependencyData> &NextData;
+	   DependencyProxy const * operator->() const { return this; }
+	   DependencyProxy * operator->() { return this; }
+	};
+	inline DependencyProxy operator->() const {return (DependencyProxy) { S2->Version, S2->Package, S->ID, S2->Type, S2->CompareOp, S->ParentVer, S->DependencyData, S->NextRevDepends, S->NextDepends, S2->NextData };}
+	inline DependencyProxy operator->() {return (DependencyProxy) { S2->Version, S2->Package, S->ID, S2->Type, S2->CompareOp, S->ParentVer, S->DependencyData, S->NextRevDepends, S->NextDepends, S2->NextData };}
+	void ReMap(void const * const oldMap, void * const newMap)
+	{
+		Iterator<Dependency, DepIterator>::ReMap(oldMap, newMap);
+		if (Owner == 0 || S == 0 || S2 == 0)
+			return;
+		S2 = static_cast<DependencyData *>(newMap) + (S2 - static_cast<DependencyData const *>(oldMap));
+	}
+
+	//Nice printable representation
+	APT_DEPRECATED_MSG("Use APT::PrettyDep instead") friend std::ostream& operator <<(std::ostream& out, DepIterator D);
+
+	inline DepIterator(pkgCache &Owner, Dependency *Trg, Version* = 0) :
+		Iterator<Dependency, DepIterator>(Owner, Trg), Type(DepVer), S2(Trg == 0 ? Owner.DepDataP : (Owner.DepDataP + Trg->DependencyData)) {
+		if (S == 0)
+			S = Owner.DepP;
+	}
+	inline DepIterator(pkgCache &Owner, Dependency *Trg, Package*) :
+		Iterator<Dependency, DepIterator>(Owner, Trg), Type(DepRev), S2(Trg == 0 ? Owner.DepDataP : (Owner.DepDataP + Trg->DependencyData)) {
+		if (S == 0)
+			S = Owner.DepP;
+	}
+	inline DepIterator() : Iterator<Dependency, DepIterator>(), Type(DepVer), S2(0) {}
+};
+									/*}}}*/
+// Provides iterator							/*{{{*/
+class APT_PUBLIC pkgCache::PrvIterator : public Iterator<Provides, PrvIterator> {
+	enum {PrvVer, PrvPkg} Type;
+
+	public:
+	inline Provides* OwnerPointer() const {
+		return (Owner != 0) ? Owner->ProvideP : 0;
+	}
+
+	// Iteration
+	inline PrvIterator& operator ++() {if (S != Owner->ProvideP) S = Owner->ProvideP +
+	   (Type == PrvVer?S->NextPkgProv:S->NextProvides); return *this;}
+	inline PrvIterator operator++(int) { PrvIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline const char *Name() const {return ParentPkg().Name();}
+	inline const char *ProvideVersion() const {return S->ProvideVersion == 0?0:Owner->StrP + S->ProvideVersion;}
+	inline PkgIterator ParentPkg() const {return PkgIterator(*Owner,Owner->PkgP + S->ParentPkg);}
+	inline VerIterator OwnerVer() const {return VerIterator(*Owner,Owner->VerP + S->Version);}
+	inline PkgIterator OwnerPkg() const {return PkgIterator(*Owner,Owner->PkgP + Owner->VerP[uint32_t(S->Version)].ParentPkg);}
+
+	/* MultiArch can be translated to SingleArch for an resolver and we did so,
+	   by adding provides to help the resolver understand the problem, but
+	   sometimes it is needed to identify these to ignore them… */
+	bool IsMultiArchImplicit() const APT_PURE
+	{ return (S->Flags & pkgCache::Flag::MultiArchImplicit) == pkgCache::Flag::MultiArchImplicit; }
+
+
+	inline PrvIterator() : Iterator<Provides, PrvIterator>(), Type(PrvVer) {}
+	inline PrvIterator(pkgCache &Owner, Provides *Trg, Version*) :
+		Iterator<Provides, PrvIterator>(Owner, Trg), Type(PrvVer) {
+		if (S == 0)
+			S = Owner.ProvideP;
+	}
+	inline PrvIterator(pkgCache &Owner, Provides *Trg, Package*) :
+		Iterator<Provides, PrvIterator>(Owner, Trg), Type(PrvPkg) {
+		if (S == 0)
+			S = Owner.ProvideP;
+	}
+};
+									/*}}}*/
+// Release file								/*{{{*/
+class APT_PUBLIC pkgCache::RlsFileIterator : public Iterator<ReleaseFile, RlsFileIterator> {
+	public:
+	inline ReleaseFile* OwnerPointer() const {
+		return (Owner != 0) ? Owner->RlsFileP : 0;
+	}
+
+	// Iteration
+	inline RlsFileIterator& operator++() {if (S != Owner->RlsFileP) S = Owner->RlsFileP + S->NextFile;return *this;}
+	inline RlsFileIterator operator++(int) { RlsFileIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline const char *FileName() const {return S->FileName == 0?0:Owner->StrP + S->FileName;}
+	inline const char *Archive() const {return S->Archive == 0?0:Owner->StrP + S->Archive;}
+	inline const char *Version() const {return S->Version == 0?0:Owner->StrP + S->Version;}
+	inline const char *Origin() const {return S->Origin == 0?0:Owner->StrP + S->Origin;}
+	inline const char *Codename() const {return S->Codename ==0?0:Owner->StrP + S->Codename;}
+	inline const char *Label() const {return S->Label == 0?0:Owner->StrP + S->Label;}
+	inline const char *Site() const {return S->Site == 0?0:Owner->StrP + S->Site;}
+	inline bool Flagged(pkgCache::Flag::ReleaseFileFlags const flag) const {return (S->Flags & flag) == flag; }
+
+	std::string RelStr();
+
+	// Constructors
+	inline RlsFileIterator() : Iterator<ReleaseFile, RlsFileIterator>() {}
+	explicit inline RlsFileIterator(pkgCache &Owner) : Iterator<ReleaseFile, RlsFileIterator>(Owner, Owner.RlsFileP) {}
+	inline RlsFileIterator(pkgCache &Owner,ReleaseFile *Trg) : Iterator<ReleaseFile, RlsFileIterator>(Owner, Trg) {}
+};
+									/*}}}*/
+// Package file								/*{{{*/
+class APT_PUBLIC pkgCache::PkgFileIterator : public Iterator<PackageFile, PkgFileIterator> {
+	public:
+	inline PackageFile* OwnerPointer() const {
+		return (Owner != 0) ? Owner->PkgFileP : 0;
+	}
+
+	// Iteration
+	inline PkgFileIterator& operator++() {if (S != Owner->PkgFileP) S = Owner->PkgFileP + S->NextFile; return *this;}
+	inline PkgFileIterator operator++(int) { PkgFileIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline const char *FileName() const {return S->FileName == 0?0:Owner->StrP + S->FileName;}
+	inline pkgCache::RlsFileIterator ReleaseFile() const {return RlsFileIterator(*Owner, Owner->RlsFileP + S->Release);}
+	inline const char *Archive() const {return S->Release == 0 ? Component() : ReleaseFile().Archive();}
+	inline const char *Version() const {return S->Release == 0 ? NULL : ReleaseFile().Version();}
+	inline const char *Origin() const {return S->Release == 0 ? NULL : ReleaseFile().Origin();}
+	inline const char *Codename() const {return S->Release == 0 ? NULL : ReleaseFile().Codename();}
+	inline const char *Label() const {return S->Release == 0 ? NULL : ReleaseFile().Label();}
+	inline const char *Site() const {return S->Release == 0 ? NULL : ReleaseFile().Site();}
+	inline bool Flagged(pkgCache::Flag::ReleaseFileFlags const flag) const {return S->Release== 0 ? false : ReleaseFile().Flagged(flag);}
+	inline bool Flagged(pkgCache::Flag::PkgFFlags const flag) const {return (S->Flags & flag) == flag;}
+	inline const char *Component() const {return S->Component == 0?0:Owner->StrP + S->Component;}
+	inline const char *Architecture() const {return S->Architecture == 0?0:Owner->StrP + S->Architecture;}
+	inline const char *IndexType() const {return S->IndexType == 0?0:Owner->StrP + S->IndexType;}
+
+	std::string RelStr();
+
+	// Constructors
+	inline PkgFileIterator() : Iterator<PackageFile, PkgFileIterator>() {}
+	explicit inline PkgFileIterator(pkgCache &Owner) : Iterator<PackageFile, PkgFileIterator>(Owner, Owner.PkgFileP) {}
+	inline PkgFileIterator(pkgCache &Owner,PackageFile *Trg) : Iterator<PackageFile, PkgFileIterator>(Owner, Trg) {}
+};
+									/*}}}*/
+// Version File								/*{{{*/
+class APT_PUBLIC pkgCache::VerFileIterator : public pkgCache::Iterator<VerFile, VerFileIterator> {
+	public:
+	inline VerFile* OwnerPointer() const {
+		return (Owner != 0) ? Owner->VerFileP : 0;
+	}
+
+	// Iteration
+	inline VerFileIterator& operator++() {if (S != Owner->VerFileP) S = Owner->VerFileP + S->NextFile; return *this;}
+	inline VerFileIterator operator++(int) { VerFileIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline PkgFileIterator File() const {return PkgFileIterator(*Owner, Owner->PkgFileP + S->File);}
+
+	inline VerFileIterator() : Iterator<VerFile, VerFileIterator>() {}
+	inline VerFileIterator(pkgCache &Owner,VerFile *Trg) : Iterator<VerFile, VerFileIterator>(Owner, Trg) {}
+};
+									/*}}}*/
+// Description File							/*{{{*/
+class APT_PUBLIC pkgCache::DescFileIterator : public Iterator<DescFile, DescFileIterator> {
+	public:
+	inline DescFile* OwnerPointer() const {
+		return (Owner != 0) ? Owner->DescFileP : 0;
+	}
+
+	// Iteration
+	inline DescFileIterator& operator++() {if (S != Owner->DescFileP) S = Owner->DescFileP + S->NextFile; return *this;}
+	inline DescFileIterator operator++(int) { DescFileIterator const tmp(*this); operator++(); return tmp; }
+
+	// Accessors
+	inline PkgFileIterator File() const {return PkgFileIterator(*Owner, Owner->PkgFileP + S->File);}
+
+	inline DescFileIterator() : Iterator<DescFile, DescFileIterator>() {}
+	inline DescFileIterator(pkgCache &Owner,DescFile *Trg) : Iterator<DescFile, DescFileIterator>(Owner, Trg) {}
+};
+									/*}}}*/
+// Inlined Begin functions can't be in the class because of order problems /*{{{*/
+inline pkgCache::PkgIterator pkgCache::GrpIterator::PackageList() const
+       {return PkgIterator(*Owner,Owner->PkgP + S->FirstPackage);}
+       inline pkgCache::VerIterator pkgCache::GrpIterator::VersionsInSource() const
+       {
+	  return VerIterator(*Owner, Owner->VerP + S->VersionsInSource);
+       }
+inline pkgCache::VerIterator pkgCache::PkgIterator::VersionList() const
+       {return VerIterator(*Owner,Owner->VerP + S->VersionList);}
+inline pkgCache::VerIterator pkgCache::PkgIterator::CurrentVer() const
+       {return VerIterator(*Owner,Owner->VerP + S->CurrentVer);}
+inline pkgCache::DepIterator pkgCache::PkgIterator::RevDependsList() const
+       {return DepIterator(*Owner,Owner->DepP + S->RevDepends,S);}
+inline pkgCache::PrvIterator pkgCache::PkgIterator::ProvidesList() const
+       {return PrvIterator(*Owner,Owner->ProvideP + S->ProvidesList,S);}
+inline pkgCache::DescIterator pkgCache::VerIterator::DescriptionList() const
+       {return DescIterator(*Owner,Owner->DescP + S->DescriptionList);}
+inline pkgCache::PrvIterator pkgCache::VerIterator::ProvidesList() const
+       {return PrvIterator(*Owner,Owner->ProvideP + S->ProvidesList,S);}
+inline pkgCache::DepIterator pkgCache::VerIterator::DependsList() const
+       {return DepIterator(*Owner,Owner->DepP + S->DependsList,S);}
+inline pkgCache::VerFileIterator pkgCache::VerIterator::FileList() const
+       {return VerFileIterator(*Owner,Owner->VerFileP + S->FileList);}
+inline pkgCache::DescFileIterator pkgCache::DescIterator::FileList() const
+       {return DescFileIterator(*Owner,Owner->DescFileP + S->FileList);}
+									/*}}}*/
+#endif
diff --git a/apt-pkg/cacheset.cc b/apt-pkg/cacheset.cc
new file mode 100644
index 0000000..e52f762
--- /dev/null
+++ b/apt-pkg/cacheset.cc
@@ -0,0 +1,939 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Simple wrapper around a std::set to provide a similar interface to
+   a set of cache structures as to the complete set of all structures
+   in the pkgCache. Currently only Package is supported.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+#include <apt-pkg/policy.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <list>
+#include <string>
+#include <vector>
+#include <regex.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+namespace APT {
+// PackageFrom - selecting the appropriate method for package selection	/*{{{*/
+bool CacheSetHelper::PackageFrom(enum PkgSelector const select, PackageContainerInterface * const pci,
+      pkgCacheFile &Cache, std::string const &pattern) {
+	switch (select) {
+	case UNKNOWN: return false;
+	case REGEX: return PackageFromRegEx(pci, Cache, pattern);
+	case TASK: return PackageFromTask(pci, Cache, pattern);
+	case FNMATCH: return PackageFromFnmatch(pci, Cache, pattern);
+	case PACKAGENAME: return PackageFromPackageName(pci, Cache, pattern);
+	case STRING: return PackageFromString(pci, Cache, pattern);
+	case PATTERN: return PackageFromPattern(pci, Cache, pattern);
+	}
+	return false;
+}
+									/*}}}*/
+// PackageFromTask - Return all packages in the cache from a specific task /*{{{*/
+bool CacheSetHelper::PackageFromTask(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern) {
+	size_t const archfound = pattern.find_last_of(':');
+	std::string arch = "native";
+	if (archfound != std::string::npos) {
+		arch = pattern.substr(archfound+1);
+		pattern.erase(archfound);
+	}
+
+	if (pattern[pattern.length() -1] != '^')
+		return false;
+	pattern.erase(pattern.length()-1);
+
+	if (unlikely(Cache.GetPkgCache() == 0 || Cache.GetDepCache() == 0))
+		return false;
+
+	bool const wasEmpty = pci->empty();
+	if (wasEmpty == true)
+		pci->setConstructor(CacheSetHelper::TASK);
+
+	// get the records
+	pkgRecords Recs(Cache);
+
+	// build regexp for the task
+	regex_t Pattern;
+	char S[300];
+	snprintf(S, sizeof(S), "^Task:.*[, ]%s([, ]|$)", pattern.c_str());
+	if(regcomp(&Pattern,S, REG_EXTENDED | REG_NOSUB | REG_NEWLINE) != 0) {
+		_error->Error("Failed to compile task regexp");
+		return false;
+	}
+
+	bool found = false;
+	for (pkgCache::GrpIterator Grp = Cache->GrpBegin(); Grp.end() == false; ++Grp) {
+		pkgCache::PkgIterator Pkg = Grp.FindPkg(arch);
+		if (Pkg.end() == true)
+			continue;
+		pkgCache::VerIterator ver = Cache[Pkg].CandidateVerIter(Cache);
+		if(ver.end() == true)
+			continue;
+
+		pkgRecords::Parser &parser = Recs.Lookup(ver.FileList());
+		const char *start, *end;
+		parser.GetRec(start,end);
+		unsigned int const length = end - start;
+		if (unlikely(length == 0))
+		   continue;
+		char buf[length];
+		strncpy(buf, start, length);
+		buf[length-1] = '\0';
+		if (regexec(&Pattern, buf, 0, 0, 0) != 0)
+			continue;
+
+		pci->insert(Pkg);
+		showPackageSelection(Pkg, CacheSetHelper::TASK, pattern);
+		found = true;
+	}
+	regfree(&Pattern);
+
+	if (found == false) {
+		canNotFindPackage(CacheSetHelper::TASK, pci, Cache, pattern);
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+		return false;
+	}
+
+	if (wasEmpty == false && pci->getConstructor() != CacheSetHelper::UNKNOWN)
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+
+	return true;
+}
+									/*}}}*/
+// PackageFromRegEx - Return all packages in the cache matching a pattern /*{{{*/
+bool CacheSetHelper::PackageFromRegEx(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern) {
+	static const char * const isregex = ".?+*|[^$";
+
+	if (_config->FindB("APT::Cmd::Pattern-Only", false))
+	{
+		// Only allow explicit regexp pattern.
+		if (pattern.size() == 0 || (pattern[0] != '^' && pattern[pattern.size() - 1] != '$'))
+			return false;
+	} else {
+		if (pattern.find_first_of(isregex) == std::string::npos)
+			return false;
+	}
+
+	bool const wasEmpty = pci->empty();
+	if (wasEmpty == true)
+		pci->setConstructor(CacheSetHelper::REGEX);
+
+	size_t archfound = pattern.find_last_of(':');
+	std::string arch = "native";
+	if (archfound != std::string::npos) {
+		arch = pattern.substr(archfound+1);
+		if (arch.find_first_of(isregex) == std::string::npos)
+			pattern.erase(archfound);
+		else
+			arch = "native";
+	}
+
+	if (unlikely(Cache.GetPkgCache() == 0))
+		return false;
+
+	APT::CacheFilter::PackageNameMatchesRegEx regexfilter(pattern);
+
+	bool found = false;
+	for (pkgCache::GrpIterator Grp = Cache.GetPkgCache()->GrpBegin(); Grp.end() == false; ++Grp) {
+		if (regexfilter(Grp) == false)
+			continue;
+		pkgCache::PkgIterator Pkg = Grp.FindPkg(arch);
+		if (Pkg.end() == true) {
+			if (archfound == std::string::npos)
+				Pkg = Grp.FindPreferredPkg(true);
+			if (Pkg.end() == true)
+				continue;
+		}
+
+		pci->insert(Pkg);
+		showPackageSelection(Pkg, CacheSetHelper::REGEX, pattern);
+		found = true;
+	}
+
+	if (found == false) {
+		canNotFindPackage(CacheSetHelper::REGEX, pci, Cache, pattern);
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+		return false;
+	}
+
+	if (wasEmpty == false && pci->getConstructor() != CacheSetHelper::UNKNOWN)
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+
+	return true;
+}
+									/*}}}*/
+// PackageFromFnmatch - Returns the package defined  by this fnmatch	/*{{{*/
+bool CacheSetHelper::PackageFromFnmatch(PackageContainerInterface * const pci,
+                                       pkgCacheFile &Cache, std::string pattern)
+{
+	static const char * const isfnmatch = ".?*[]!";
+	// Whitelist approach: Anything not in here is not a valid pattern
+	static const char *const isfnmatch_strict = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+-.:*";
+
+	if (_config->FindB("APT::Cmd::Pattern-Only", false) && pattern.find_first_not_of(isfnmatch_strict) != std::string::npos)
+	   return false;
+	if (pattern.find_first_of(isfnmatch) == std::string::npos)
+		return false;
+
+	bool const wasEmpty = pci->empty();
+	if (wasEmpty == true)
+		pci->setConstructor(CacheSetHelper::FNMATCH);
+
+	size_t archfound = pattern.find_last_of(':');
+	std::string arch = "native";
+	if (archfound != std::string::npos) {
+		arch = pattern.substr(archfound+1);
+		if (arch.find_first_of(isfnmatch) == std::string::npos)
+			pattern.erase(archfound);
+		else
+			arch = "native";
+	}
+
+	if (unlikely(Cache.GetPkgCache() == 0))
+		return false;
+
+	APT::CacheFilter::PackageNameMatchesFnmatch filter(pattern);
+
+	bool found = false;
+	for (pkgCache::GrpIterator Grp = Cache.GetPkgCache()->GrpBegin(); Grp.end() == false; ++Grp) {
+		if (filter(Grp) == false)
+			continue;
+		pkgCache::PkgIterator Pkg = Grp.FindPkg(arch);
+		if (Pkg.end() == true) {
+			if (archfound == std::string::npos)
+				Pkg = Grp.FindPreferredPkg(true);
+			if (Pkg.end() == true)
+				continue;
+		}
+
+		pci->insert(Pkg);
+		showPackageSelection(Pkg, CacheSetHelper::FNMATCH, pattern);
+		found = true;
+	}
+
+	if (found == false) {
+		canNotFindPackage(CacheSetHelper::FNMATCH, pci, Cache, pattern);
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+		return false;
+	}
+
+	if (wasEmpty == false && pci->getConstructor() != CacheSetHelper::UNKNOWN)
+		pci->setConstructor(CacheSetHelper::UNKNOWN);
+
+	return true;
+}
+									/*}}}*/
+// PackageFromPackageName - Returns the package defined  by this string /*{{{*/
+bool CacheSetHelper::PackageFromPackageName(PackageContainerInterface * const pci, pkgCacheFile &Cache,
+			std::string pkg) {
+	if (unlikely(Cache.GetPkgCache() == 0))
+		return false;
+
+	std::string const pkgstring = pkg;
+	size_t const archfound = pkg.find_last_of(':');
+	std::string arch;
+	if (archfound != std::string::npos) {
+		arch = pkg.substr(archfound+1);
+		pkg.erase(archfound);
+		if (arch == "all" || arch == "native")
+			arch = _config->Find("APT::Architecture");
+	}
+
+	pkgCache::GrpIterator Grp = Cache.GetPkgCache()->FindGrp(pkg);
+	if (Grp.end() == false) {
+		if (arch.empty() == true) {
+			pkgCache::PkgIterator Pkg = Grp.FindPreferredPkg();
+			if (Pkg.end() == false)
+			{
+			   pci->insert(Pkg);
+			   return true;
+			}
+		} else {
+			bool found = false;
+			// for 'linux-any' return the first package matching, for 'linux-*' return all matches
+			bool const isGlobal = arch.find('*') != std::string::npos;
+			APT::CacheFilter::PackageArchitectureMatchesSpecification pams(arch);
+			for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg)) {
+				if (pams(Pkg) == false)
+					continue;
+				pci->insert(Pkg);
+				found = true;
+				if (isGlobal == false)
+					break;
+			}
+			if (found == true)
+				return true;
+		}
+	}
+
+	pkgCache::PkgIterator Pkg = canNotFindPkgName(Cache, pkgstring);
+	if (Pkg.end() == true)
+	   return false;
+
+	pci->insert(Pkg);
+	return true;
+}
+									/*}}}*/
+// PackageFromPattern - Return all packages matching a specific pattern	/*{{{*/
+bool CacheSetHelper::PackageFromPattern(PackageContainerInterface *const pci, pkgCacheFile &Cache, std::string const &pattern)
+{
+   if (pattern.size() < 1 || (pattern[0] != '?' && pattern[0] != '~'))
+      return false;
+
+   auto compiledPattern = APT::CacheFilter::ParsePattern(pattern, &Cache);
+   if (!compiledPattern)
+      return false;
+
+   for (pkgCache::PkgIterator Pkg = Cache->PkgBegin(); Pkg.end() == false; ++Pkg)
+   {
+      if ((*compiledPattern)(Pkg) == false)
+	 continue;
+
+      pci->insert(Pkg);
+   }
+   return true;
+}
+									/*}}}*/
+// PackageFromString - Return all packages matching a specific string	/*{{{*/
+bool CacheSetHelper::PackageFromString(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string const &str) {
+	bool found = true;
+	_error->PushToStack();
+
+	if (PackageFrom(CacheSetHelper::PATTERN, pci, Cache, str) == false &&
+	     PackageFrom(CacheSetHelper::PACKAGENAME, pci, Cache, str) == false &&
+		 PackageFrom(CacheSetHelper::TASK, pci, Cache, str) == false &&
+		 // FIXME: hm, hm, regexp/fnmatch incompatible?
+		 PackageFrom(CacheSetHelper::FNMATCH, pci, Cache, str) == false &&
+		 PackageFrom(CacheSetHelper::REGEX, pci, Cache, str) == false)
+	{
+		canNotFindPackage(CacheSetHelper::PACKAGENAME, pci, Cache, str);
+		found = false;
+	}
+
+	if (found == true)
+		_error->RevertToStack();
+	else
+		_error->MergeWithStack();
+	return found;
+}
+									/*}}}*/
+// PackageFromCommandLine - Return all packages specified on commandline /*{{{*/
+bool CacheSetHelper::PackageFromCommandLine(PackageContainerInterface * const pci, pkgCacheFile &Cache, const char **cmdline) {
+	bool found = false;
+	for (const char **I = cmdline; *I != 0; ++I)
+		found |= PackageFrom(CacheSetHelper::STRING, pci, Cache, *I);
+	return found;
+}
+									/*}}}*/
+// FromModifierCommandLine - helper doing the work for PKG:GroupedFromCommandLine	/*{{{*/
+bool CacheSetHelper::PackageFromModifierCommandLine(unsigned short &modID, PackageContainerInterface * const pci,
+							pkgCacheFile &Cache, const char * cmdline,
+							std::list<PkgModifier> const &mods) {
+	std::string str = cmdline;
+	unsigned short fallback = modID;
+	bool modifierPresent = false;
+	for (std::list<PkgModifier>::const_iterator mod = mods.begin();
+	     mod != mods.end(); ++mod) {
+		size_t const alength = strlen(mod->Alias);
+		switch(mod->Pos) {
+		case PkgModifier::POSTFIX:
+			if (str.compare(str.length() - alength, alength,
+					mod->Alias, 0, alength) != 0)
+				continue;
+			str.erase(str.length() - alength);
+			modID = mod->ID;
+			break;
+		case PkgModifier::PREFIX:
+			continue;
+		case PkgModifier::NONE:
+			continue;
+		}
+		modifierPresent = true;
+		break;
+	}
+	if (modifierPresent == true) {
+		bool const errors = showErrors(false);
+		bool const found = PackageFrom(PACKAGENAME, pci, Cache, cmdline);
+		showErrors(errors);
+		if (found == true) {
+			modID = fallback;
+			return true;
+		}
+	}
+	return PackageFrom(CacheSetHelper::PACKAGENAME, pci, Cache, str);
+}
+									/*}}}*/
+// FromModifierCommandLine - helper doing the work for VER:GroupedFromCommandLine	/*{{{*/
+bool VersionContainerInterface::FromModifierCommandLine(unsigned short &modID,
+							VersionContainerInterface * const vci,
+							pkgCacheFile &Cache, const char * cmdline,
+							std::list<Modifier> const &mods,
+							CacheSetHelper &helper) {
+	CacheSetHelper::VerSelector select = CacheSetHelper::NEWEST;
+	std::string str = cmdline;
+	if (unlikely(str.empty() == true))
+		return false;
+	bool modifierPresent = false;
+	unsigned short fallback = modID;
+	for (std::list<Modifier>::const_iterator mod = mods.begin();
+	     mod != mods.end(); ++mod) {
+		if (modID == fallback && mod->ID == fallback)
+			select = mod->SelectVersion;
+		size_t const alength = strlen(mod->Alias);
+		switch(mod->Pos) {
+		case Modifier::POSTFIX:
+			if (str.length() <= alength ||
+			      str.compare(str.length() - alength, alength, mod->Alias, 0, alength) != 0)
+				continue;
+			str.erase(str.length() - alength);
+			modID = mod->ID;
+			select = mod->SelectVersion;
+			break;
+		case Modifier::PREFIX:
+			continue;
+		case Modifier::NONE:
+			continue;
+		}
+		modifierPresent = true;
+		break;
+	}
+	if (modifierPresent == true) {
+		bool const errors = helper.showErrors(false);
+		bool const found = VersionContainerInterface::FromString(vci, Cache, cmdline, select, helper, true);
+		helper.showErrors(errors);
+		if (found == true) {
+			modID = fallback;
+			return true;
+		}
+	}
+	return FromString(vci, Cache, str, select, helper);
+}
+									/*}}}*/
+// FromCommandLine - Return all versions specified on commandline	/*{{{*/
+bool VersionContainerInterface::FromCommandLine(VersionContainerInterface * const vci,
+						pkgCacheFile &Cache, const char **cmdline,
+						CacheSetHelper::VerSelector const fallback,
+						CacheSetHelper &helper) {
+	bool found = false;
+	for (const char **I = cmdline; *I != 0; ++I)
+		found |= VersionContainerInterface::FromString(vci, Cache, *I, fallback, helper);
+	return found;
+}
+									/*}}}*/
+// FromString - Returns all versions spedcified by a string		/*{{{*/
+bool VersionContainerInterface::FromString(VersionContainerInterface * const vci,
+					   pkgCacheFile &Cache, std::string pkg,
+					   CacheSetHelper::VerSelector const fallback,
+					   CacheSetHelper &helper,
+					   bool const onlyFromName) {
+	std::string ver;
+	bool verIsRel = false;
+	size_t const vertag = pkg.find_last_of("/=");
+	if (vertag != std::string::npos) {
+		ver = pkg.substr(vertag+1);
+		verIsRel = (pkg[vertag] == '/');
+		pkg.erase(vertag);
+	}
+
+	PackageSet pkgset;
+	if (onlyFromName == false)
+		helper.PackageFrom(CacheSetHelper::STRING, &pkgset, Cache, pkg);
+	else {
+		helper.PackageFrom(CacheSetHelper::PACKAGENAME, &pkgset, Cache, pkg);
+	}
+
+	bool errors = true;
+	if (pkgset.getConstructor() != CacheSetHelper::UNKNOWN)
+		errors = helper.showErrors(false);
+
+	bool found = false;
+	for (PackageSet::const_iterator P = pkgset.begin();
+	     P != pkgset.end(); ++P) {
+		if (vertag == std::string::npos) {
+			found |= VersionContainerInterface::FromPackage(vci, Cache, P, fallback, helper);
+			continue;
+		}
+		pkgCache::VerIterator V;
+		if (ver == "installed")
+			V = getInstalledVer(Cache, P, helper);
+		else if (ver == "candidate")
+			V = getCandidateVer(Cache, P, helper);
+		else if (ver == "newest") {
+			if (P->VersionList != 0)
+				V = P.VersionList();
+			else
+				V = helper.canNotGetVersion(CacheSetHelper::NEWEST, Cache, P);
+		} else {
+			pkgVersionMatch Match(ver, (verIsRel == true ? pkgVersionMatch::Release :
+					pkgVersionMatch::Version));
+			V = Match.Find(P);
+			helper.setLastVersionMatcher(ver);
+			if (V.end()) {
+				if (verIsRel == true)
+					V = helper.canNotGetVersion(CacheSetHelper::RELEASE, Cache, P);
+				else
+					V = helper.canNotGetVersion(CacheSetHelper::VERSIONNUMBER, Cache, P);
+			}
+		}
+		if (V.end() == true)
+			continue;
+		if (verIsRel == true)
+			helper.showVersionSelection(P, V, CacheSetHelper::RELEASE, ver);
+		else
+			helper.showVersionSelection(P, V, CacheSetHelper::VERSIONNUMBER, ver);
+		vci->insert(V);
+		found = true;
+	}
+	if (pkgset.getConstructor() != CacheSetHelper::UNKNOWN)
+		helper.showErrors(errors);
+	return found;
+}
+									/*}}}*/
+// FromPackage - versions from package based on fallback		/*{{{*/
+bool VersionContainerInterface::FromPackage(VersionContainerInterface * const vci,
+					    pkgCacheFile &Cache,
+					    pkgCache::PkgIterator const &P,
+					    CacheSetHelper::VerSelector const fallback,
+					    CacheSetHelper &helper) {
+	pkgCache::VerIterator V;
+	bool showErrors;
+	bool found = false;
+	switch(fallback) {
+	case CacheSetHelper::ALL:
+		if (P->VersionList != 0)
+			for (V = P.VersionList(); V.end() != true; ++V)
+				found |= vci->insert(V);
+		else
+			helper.canNotFindVersion(CacheSetHelper::ALL, vci, Cache, P);
+		break;
+	case CacheSetHelper::CANDANDINST:
+		found |= vci->insert(getInstalledVer(Cache, P, helper));
+		found |= vci->insert(getCandidateVer(Cache, P, helper));
+		break;
+	case CacheSetHelper::CANDIDATE:
+		found |= vci->insert(getCandidateVer(Cache, P, helper));
+		break;
+	case CacheSetHelper::INSTALLED:
+		found |= vci->insert(getInstalledVer(Cache, P, helper));
+		break;
+	case CacheSetHelper::CANDINST:
+		showErrors = helper.showErrors(false);
+		V = getCandidateVer(Cache, P, helper);
+		if (V.end() == true)
+			V = getInstalledVer(Cache, P, helper);
+		helper.showErrors(showErrors);
+		if (V.end() == false)
+			found |= vci->insert(V);
+		else
+			helper.canNotFindVersion(CacheSetHelper::CANDINST, vci, Cache, P);
+		break;
+	case CacheSetHelper::INSTCAND:
+		showErrors = helper.showErrors(false);
+		V = getInstalledVer(Cache, P, helper);
+		if (V.end() == true)
+			V = getCandidateVer(Cache, P, helper);
+		helper.showErrors(showErrors);
+		if (V.end() == false)
+			found |= vci->insert(V);
+		else
+			helper.canNotFindVersion(CacheSetHelper::INSTCAND, vci, Cache, P);
+		break;
+	case CacheSetHelper::NEWEST:
+		if (P->VersionList != 0)
+			found |= vci->insert(P.VersionList());
+		else
+			helper.canNotFindVersion(CacheSetHelper::NEWEST, vci, Cache, P);
+		break;
+	case CacheSetHelper::RELEASE:
+		{
+		pkgVersionMatch Match(helper.getLastVersionMatcher(), pkgVersionMatch::Release);
+		V = Match.Find(P);
+		if (not V.end())
+			found |= vci->insert(V);
+		else
+			helper.canNotFindVersion(CacheSetHelper::RELEASE, vci, Cache, P);
+		}
+		break;
+	case CacheSetHelper::VERSIONNUMBER:
+		{
+		pkgVersionMatch Match(helper.getLastVersionMatcher(), pkgVersionMatch::Version);
+		V = Match.Find(P);
+		if (not V.end())
+			found |= vci->insert(V);
+		else
+			helper.canNotFindVersion(CacheSetHelper::VERSIONNUMBER, vci, Cache, P);
+		}
+		break;
+	}
+	return found;
+}
+									/*}}}*/
+// FromDependency - versions satisfying a given dependency		/*{{{*/
+bool VersionContainerInterface::FromDependency(VersionContainerInterface * const vci,
+					       pkgCacheFile &Cache,
+					       pkgCache::DepIterator const &D,
+					       CacheSetHelper::VerSelector const selector,
+					       CacheSetHelper &helper)
+{
+	bool found = false;
+	auto const insertVersion = [&](pkgCache::PkgIterator const &TP, pkgCache::VerIterator const &TV) {
+		if (not TV.end() && not D.IsIgnorable(TP) && D.IsSatisfied(TV))
+		{
+		   vci->insert(TV);
+		   found = true;
+		}
+	};
+	pkgCache::PkgIterator const T = D.TargetPkg();
+	auto const insertAllTargetVersions = [&](auto const &getTargetVersion) {
+		insertVersion(T, getTargetVersion(T));
+		for (auto Prv = T.ProvidesList(); not Prv.end(); ++Prv)
+		{
+		   if (D.IsIgnorable(Prv))
+		      continue;
+		   auto const OP = Prv.OwnerPkg();
+		   auto const TV = getTargetVersion(OP);
+		   if (Prv.OwnerVer() == TV && D.IsSatisfied(Prv))
+		   {
+		      vci->insert(TV);
+		      found = true;
+		   }
+		}
+		return found;
+	};
+	switch(selector) {
+	case CacheSetHelper::ALL:
+		for (auto Ver = T.VersionList(); not Ver.end(); ++Ver)
+		{
+		   insertVersion(T, Ver);
+		   for (pkgCache::PrvIterator Prv = T.ProvidesList(); not Prv.end(); ++Prv)
+		      if (not D.IsIgnorable(Prv))
+		      {
+			 vci->insert(Prv.OwnerVer());
+			 found = true;
+		      }
+		}
+		return found;
+	case CacheSetHelper::CANDANDINST:
+		found = FromDependency(vci, Cache, D, CacheSetHelper::CANDIDATE, helper);
+		found &= FromDependency(vci, Cache, D, CacheSetHelper::INSTALLED, helper);
+		return found;
+	case CacheSetHelper::CANDIDATE:
+		// skip looking if we have already cached that we will find nothing
+		if (((Cache[D] & pkgDepCache::DepCVer) == 0) != D.IsNegative())
+		   return found;
+		return insertAllTargetVersions([&](pkgCache::PkgIterator const &OP) { return Cache[OP].CandidateVerIter(Cache); });
+	case CacheSetHelper::INSTALLED:
+		return insertAllTargetVersions([&](pkgCache::PkgIterator const &OP) { return OP.CurrentVer(); });
+	case CacheSetHelper::CANDINST:
+		return FromDependency(vci, Cache, D, CacheSetHelper::CANDIDATE, helper) ||
+		   FromDependency(vci, Cache, D, CacheSetHelper::INSTALLED, helper);
+	case CacheSetHelper::INSTCAND:
+		return FromDependency(vci, Cache, D, CacheSetHelper::INSTALLED, helper) ||
+		   FromDependency(vci, Cache, D, CacheSetHelper::CANDIDATE, helper);
+	case CacheSetHelper::NEWEST:
+		return insertAllTargetVersions([&](pkgCache::PkgIterator const &OP) { return OP.VersionList(); });
+	case CacheSetHelper::RELEASE:
+	case CacheSetHelper::VERSIONNUMBER:
+		// both make no sense here, so always false
+		return false;
+	}
+	return found;
+}
+									/*}}}*/
+// getCandidateVer - Returns the candidate version of the given package	/*{{{*/
+pkgCache::VerIterator VersionContainerInterface::getCandidateVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, CacheSetHelper &helper) {
+	pkgCache::VerIterator Cand;
+	if (Cache.IsDepCacheBuilt() == true) {
+		Cand = Cache[Pkg].CandidateVerIter(Cache);
+	} else if (unlikely(Cache.GetPolicy() == nullptr)) {
+		return pkgCache::VerIterator(Cache);
+	} else {
+		Cand = Cache.GetPolicy()->GetCandidateVer(Pkg);
+	}
+	if (Cand.end() == true)
+		return helper.canNotGetVersion(CacheSetHelper::CANDIDATE, Cache, Pkg);
+	return Cand;
+}
+									/*}}}*/
+// getInstalledVer - Returns the installed version of the given package	/*{{{*/
+pkgCache::VerIterator VersionContainerInterface::getInstalledVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, CacheSetHelper &helper) {
+	if (Pkg->CurrentVer == 0)
+		return helper.canNotGetVersion(CacheSetHelper::INSTALLED, Cache, Pkg);
+	return Pkg.CurrentVer();
+}
+									/*}}}*/
+
+// canNotFindPackage - with the given selector and pattern		/*{{{*/
+void CacheSetHelper::canNotFindPackage(enum PkgSelector const select,
+      PackageContainerInterface * const pci, pkgCacheFile &Cache,
+      std::string const &pattern) {
+	switch (select) {
+	case REGEX: canNotFindRegEx(pci, Cache, pattern); break;
+	case TASK: canNotFindTask(pci, Cache, pattern); break;
+	case FNMATCH: canNotFindFnmatch(pci, Cache, pattern); break;
+	case PACKAGENAME: canNotFindPackage(pci, Cache, pattern); break;
+	case STRING: canNotFindPackage(pci, Cache, pattern); break;
+	case PATTERN: canNotFindPackage(pci, Cache, pattern); break;
+	case UNKNOWN: break;
+	}
+}
+// canNotFindTask - handle the case no package is found for a task	/*{{{*/
+void CacheSetHelper::canNotFindTask(PackageContainerInterface * const /*pci*/, pkgCacheFile &/*Cache*/, std::string pattern) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Couldn't find task '%s'"), pattern.c_str());
+}
+									/*}}}*/
+// canNotFindRegEx - handle the case no package is found by a regex	/*{{{*/
+void CacheSetHelper::canNotFindRegEx(PackageContainerInterface * const /*pci*/, pkgCacheFile &/*Cache*/, std::string pattern) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Couldn't find any package by regex '%s'"), pattern.c_str());
+}
+									/*}}}*/
+// canNotFindFnmatch - handle the case no package is found by a fnmatch	/*{{{*/
+   void CacheSetHelper::canNotFindFnmatch(PackageContainerInterface * const /*pci*/, pkgCacheFile &/*Cache*/, std::string pattern) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Couldn't find any package by glob '%s'"), pattern.c_str());
+}
+									/*}}}*/
+// canNotFindPackage - handle the case no package is found from a string/*{{{*/
+void CacheSetHelper::canNotFindPackage(PackageContainerInterface * const /*pci*/, pkgCacheFile &/*Cache*/, std::string const &/*str*/) {
+}
+									/*}}}*/
+									/*}}}*/
+// canNotFindPkgName - handle the case no package has this name		/*{{{*/
+pkgCache::PkgIterator CacheSetHelper::canNotFindPkgName(pkgCacheFile &Cache,
+			std::string const &str) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Unable to locate package %s"), str.c_str());
+	return pkgCache::PkgIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindVersion - for package by selector				/*{{{*/
+void CacheSetHelper::canNotFindVersion(enum VerSelector const select, VersionContainerInterface * const vci, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg)
+{
+	switch (select) {
+	case ALL: canNotFindAllVer(vci, Cache, Pkg); break;
+	case INSTCAND: canNotFindInstCandVer(vci, Cache, Pkg); break;
+	case CANDINST: canNotFindCandInstVer(vci, Cache, Pkg); break;
+	case NEWEST: canNotFindNewestVer(Cache, Pkg); break;
+	case CANDIDATE: canNotFindCandidateVer(Cache, Pkg); break;
+	case INSTALLED: canNotFindInstalledVer(Cache, Pkg); break;
+	case CANDANDINST: canNotGetCandInstVer(Cache, Pkg); break;
+	case RELEASE: canNotGetVerFromRelease(Cache, Pkg, getLastVersionMatcher()); break;
+	case VERSIONNUMBER: canNotGetVerFromVersionNumber(Cache, Pkg, getLastVersionMatcher()); break;
+	}
+}
+// canNotFindAllVer							/*{{{*/
+void CacheSetHelper::canNotFindAllVer(VersionContainerInterface * const /*vci*/, pkgCacheFile &/*Cache*/,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select versions from package '%s' as it is purely virtual"), Pkg.FullName(true).c_str());
+}
+									/*}}}*/
+// canNotFindInstCandVer						/*{{{*/
+void CacheSetHelper::canNotFindInstCandVer(VersionContainerInterface * const /*vci*/, pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	canNotGetInstCandVer(Cache, Pkg);
+}
+									/*}}}*/
+// canNotFindInstCandVer						/*{{{*/
+void CacheSetHelper::canNotFindCandInstVer(VersionContainerInterface * const /*vci*/, pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	canNotGetCandInstVer(Cache, Pkg);
+}
+									/*}}}*/
+									/*}}}*/
+// canNotGetVersion - for package by selector				/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotGetVersion(enum VerSelector const select, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg) {
+	switch (select) {
+	case NEWEST: return canNotFindNewestVer(Cache, Pkg);
+	case CANDIDATE: return canNotFindCandidateVer(Cache, Pkg);
+	case INSTALLED: return canNotFindInstalledVer(Cache, Pkg);
+	case CANDINST: return canNotGetCandInstVer(Cache, Pkg);
+	case INSTCAND: return canNotGetInstCandVer(Cache, Pkg);
+	case RELEASE: return canNotGetVerFromRelease(Cache, Pkg, getLastVersionMatcher());
+	case VERSIONNUMBER: return canNotGetVerFromVersionNumber(Cache, Pkg, getLastVersionMatcher());
+	case ALL:
+	case CANDANDINST:
+		// invalid in this branch
+		return pkgCache::VerIterator(Cache, 0);
+	}
+	return pkgCache::VerIterator(Cache, 0);
+}
+// canNotFindNewestVer							/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotFindNewestVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select newest version from package '%s' as it is purely virtual"), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindCandidateVer						/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotFindCandidateVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select candidate version from package %s as it has no candidate"), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindInstalledVer						/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotFindInstalledVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select installed version from package %s as it is not installed"), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindInstCandVer						/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotGetInstCandVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select installed nor candidate version from package '%s' as it has neither of them"), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindInstCandVer						/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotGetCandInstVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Can't select installed nor candidate version from package '%s' as it has neither of them"), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+// canNotFindMatchingVer						/*{{{*/
+pkgCache::VerIterator CacheSetHelper::canNotGetVerFromRelease(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, std::string const &release) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Release '%s' for '%s' was not found"), release.c_str(), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+pkgCache::VerIterator CacheSetHelper::canNotGetVerFromVersionNumber(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, std::string const &verstr) {
+	if (ShowError == true)
+		_error->Insert(ErrorType, _("Version '%s' for '%s' was not found"), verstr.c_str(), Pkg.FullName(true).c_str());
+	return pkgCache::VerIterator(Cache, 0);
+}
+									/*}}}*/
+									/*}}}*/
+// showPackageSelection - by selector and given pattern			/*{{{*/
+void CacheSetHelper::showPackageSelection(pkgCache::PkgIterator const &pkg, enum PkgSelector const select,
+				       std::string const &pattern) {
+	switch (select) {
+	case REGEX: showRegExSelection(pkg, pattern); break;
+	case TASK: showTaskSelection(pkg, pattern); break;
+	case FNMATCH: showFnmatchSelection(pkg, pattern); break;
+	case PATTERN: showPatternSelection(pkg, pattern); break;
+	case PACKAGENAME: /* no surprises here */ break;
+	case STRING: /* handled by the special cases */ break;
+	case UNKNOWN: break;
+	}
+}
+// showTaskSelection							/*{{{*/
+void CacheSetHelper::showTaskSelection(pkgCache::PkgIterator const &/*pkg*/,
+				       std::string const &/*pattern*/) {
+}
+									/*}}}*/
+// showRegExSelection							/*{{{*/
+void CacheSetHelper::showRegExSelection(pkgCache::PkgIterator const &/*pkg*/,
+					std::string const &/*pattern*/) {
+}
+									/*}}}*/
+// showFnmatchSelection							/*{{{*/
+void CacheSetHelper::showFnmatchSelection(pkgCache::PkgIterator const &/*pkg*/,
+                                         std::string const &/*pattern*/) {
+}
+									/*}}}*/
+// showPatternSelection							/*{{{*/
+void CacheSetHelper::showPatternSelection(pkgCache::PkgIterator const & /*pkg*/,
+					  std::string const & /*pattern*/)
+{
+}
+									/*}}}*/
+									/*}}}*/
+// showVersionSelection							/*{{{*/
+void CacheSetHelper::showVersionSelection(pkgCache::PkgIterator const &Pkg,
+      pkgCache::VerIterator const &Ver, enum VerSelector const select, std::string const &pattern) {
+	switch (select) {
+	case RELEASE:
+		showSelectedVersion(Pkg, Ver, pattern, true);
+		break;
+	case VERSIONNUMBER:
+		showSelectedVersion(Pkg, Ver, pattern, false);
+		break;
+	case NEWEST:
+	case CANDIDATE:
+	case INSTALLED:
+	case CANDINST:
+	case INSTCAND:
+	case ALL:
+	case CANDANDINST:
+		// not really surprises, but in fact: just not implemented
+		break;
+	}
+}
+void CacheSetHelper::showSelectedVersion(pkgCache::PkgIterator const &/*Pkg*/,
+					 pkgCache::VerIterator const /*Ver*/,
+					 std::string const &/*ver*/,
+					 bool const /*verIsRel*/) {
+}
+									/*}}}*/
+
+class CacheSetHelper::Private {
+public:
+   std::string version_or_release;
+};
+std::string CacheSetHelper::getLastVersionMatcher() const { return d->version_or_release; }
+void CacheSetHelper::setLastVersionMatcher(std::string const &matcher) { d->version_or_release = matcher; }
+
+CacheSetHelper::CacheSetHelper(bool const ShowError, GlobalError::MsgType ErrorType) :
+   ShowError(ShowError), ErrorType(ErrorType), d(new Private{}) {}
+CacheSetHelper::~CacheSetHelper() { delete d; }
+
+PackageContainerInterface::PackageContainerInterface() : ConstructedBy(CacheSetHelper::UNKNOWN), d(NULL) {}
+PackageContainerInterface::PackageContainerInterface(PackageContainerInterface const &by) : PackageContainerInterface() { *this = by; }
+PackageContainerInterface::PackageContainerInterface(CacheSetHelper::PkgSelector const by) : ConstructedBy(by), d(NULL) {}
+PackageContainerInterface& PackageContainerInterface::operator=(PackageContainerInterface const &other) {
+   if (this != &other)
+      this->ConstructedBy = other.ConstructedBy;
+   return *this;
+}
+PackageContainerInterface::~PackageContainerInterface() {}
+
+PackageUniverse::PackageUniverse(pkgCache * const Owner) : _cont(Owner), d(NULL) {}
+PackageUniverse::PackageUniverse(pkgCacheFile * const Owner) : _cont(Owner->GetPkgCache()), d(NULL) {}
+PackageUniverse::~PackageUniverse() {}
+
+VersionContainerInterface::VersionContainerInterface() : d(NULL) {}
+VersionContainerInterface::VersionContainerInterface(VersionContainerInterface const &other) : VersionContainerInterface() {
+	*this = other;
+};
+VersionContainerInterface& VersionContainerInterface::operator=(VersionContainerInterface const &) {
+   return *this;
+}
+
+VersionContainerInterface::~VersionContainerInterface() {}
+}
diff --git a/apt-pkg/cacheset.h b/apt-pkg/cacheset.h
new file mode 100644
index 0000000..4ea78bc
--- /dev/null
+++ b/apt-pkg/cacheset.h
@@ -0,0 +1,1079 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/** \file cacheset.h
+   Wrappers around std::set to have set::iterators which behave
+   similar to the Iterators of the cache structures.
+
+   Provides also a few helper methods which work with these sets */
+									/*}}}*/
+#ifndef APT_CACHESET_H
+#define APT_CACHESET_H
+// Include Files							/*{{{*/
+#include <fstream>
+#include <map>
+#include <set>
+#if __cplusplus >= 201103L
+#include <forward_list>
+#include <initializer_list>
+#include <unordered_set>
+#endif
+#include <algorithm>
+#include <deque>
+#include <iterator>
+#include <list>
+#include <string>
+#include <vector>
+
+#include <stddef.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+									/*}}}*/
+
+class pkgCacheFile;
+
+namespace APT {
+class PackageContainerInterface;
+class VersionContainerInterface;
+
+class APT_PUBLIC CacheSetHelper {							/*{{{*/
+/** \class APT::CacheSetHelper
+    Simple base class with a lot of virtual methods which can be overridden
+    to alter the behavior or the output of the CacheSets.
+
+    This helper is passed around by the static methods in the CacheSets and
+    used every time they hit an error condition or something could be
+    printed out.
+*/
+public:									/*{{{*/
+	CacheSetHelper(bool const ShowError = true,
+		GlobalError::MsgType ErrorType = GlobalError::ERROR);
+	virtual ~CacheSetHelper();
+
+	enum PkgSelector { UNKNOWN, REGEX, TASK, FNMATCH, PACKAGENAME, STRING, PATTERN };
+
+	virtual bool PackageFrom(enum PkgSelector const select, PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string const &pattern);
+
+	virtual bool PackageFromCommandLine(PackageContainerInterface * const pci, pkgCacheFile &Cache, const char **cmdline);
+
+	struct PkgModifier {
+		enum Position { NONE, PREFIX, POSTFIX };
+		unsigned short ID;
+		const char * const Alias;
+		Position Pos;
+		PkgModifier (unsigned short const &id, const char * const alias, Position const &pos) : ID(id), Alias(alias), Pos(pos) {}
+	};
+	virtual bool PackageFromModifierCommandLine(unsigned short &modID, PackageContainerInterface * const pci,
+					    pkgCacheFile &Cache, const char * cmdline,
+					    std::list<PkgModifier> const &mods);
+
+
+	/** \brief be notified about the package being selected via pattern
+	 *
+	 * Main use is probably to show a message to the user what happened
+	 *
+	 * \param pkg is the package which was selected
+	 * \param select is the selection method which choose the package
+	 * \param pattern is the string used by the selection method to pick the package
+	 */
+	virtual void showPackageSelection(pkgCache::PkgIterator const &pkg, PkgSelector const select, std::string const &pattern);
+
+	/** \brief be notified if a package can't be found via pattern
+	 *
+	 * Can be used to show a message as well as to try something else to make it match
+	 *
+	 * \param select is the method tried for selection
+	 * \param pci is the container the package should be inserted in
+	 * \param Cache is the package universe available
+	 * \param pattern is the string not matching anything
+	 */
+	virtual void canNotFindPackage(enum PkgSelector const select, PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string const &pattern);
+
+	/** \brief specifies which version(s) we want to refer to */
+	enum VerSelector {
+		/** by release string */
+		RELEASE,
+		/** by version number string */
+		VERSIONNUMBER,
+		/** All versions */
+		ALL,
+		/** Candidate and installed version */
+		CANDANDINST,
+		/** Candidate version */
+		CANDIDATE,
+		/** Installed version */
+		INSTALLED,
+		/** Candidate or if non installed version */
+		CANDINST,
+		/** Installed or if non candidate version */
+		INSTCAND,
+		/** Newest version */
+		NEWEST
+	};
+
+	/** \brief be notified about the version being selected via pattern
+	 *
+	 * Main use is probably to show a message to the user what happened
+	 * Note that at the moment this method is only called for RELEASE
+	 * and VERSION selections, not for the others.
+	 *
+	 * \param Pkg is the package which was selected for
+	 * \param Ver is the version selected
+	 * \param select is the selection method which choose the version
+	 * \param pattern is the string used by the selection method to pick the version
+	 */
+	virtual void showVersionSelection(pkgCache::PkgIterator const &Pkg, pkgCache::VerIterator const &Ver,
+	      enum VerSelector const select, std::string const &pattern);
+
+	/** \brief be notified if a version can't be found for a package
+	 *
+	 * Main use is probably to show a message to the user what happened
+	 *
+	 * \param select is the method tried for selection
+	 * \param vci is the container the version should be inserted in
+	 * \param Cache is the package universe available
+	 * \param Pkg is the package we wanted a version from
+	 */
+	virtual void canNotFindVersion(enum VerSelector const select, VersionContainerInterface * const vci, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+
+	// the difference between canNotFind and canNotGet is that the later is more low-level
+	// and called from other places: In this case looking into the code is the only real answer…
+	virtual pkgCache::VerIterator canNotGetVersion(enum VerSelector const select, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+
+	virtual pkgCache::PkgIterator canNotFindPkgName(pkgCacheFile &Cache, std::string const &str);
+
+	bool showErrors() const { return ShowError; }
+	bool showErrors(bool const newValue) { if (ShowError == newValue) return ShowError; else return ((ShowError = newValue) == false); }
+	GlobalError::MsgType errorType() const { return ErrorType; }
+	GlobalError::MsgType errorType(GlobalError::MsgType const &newValue)
+	{
+		if (ErrorType == newValue) return ErrorType;
+		else {
+			GlobalError::MsgType const &oldValue = ErrorType;
+			ErrorType = newValue;
+			return oldValue;
+		}
+	}
+
+	std::string getLastVersionMatcher() const;
+	void setLastVersionMatcher(std::string const &matcher);
+									/*}}}*/
+protected:
+	bool ShowError;
+	GlobalError::MsgType ErrorType;
+
+	pkgCache::VerIterator canNotGetInstCandVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg);
+	pkgCache::VerIterator canNotGetCandInstVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg);
+
+	pkgCache::VerIterator canNotGetVerFromRelease(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, std::string const &release);
+	pkgCache::VerIterator canNotGetVerFromVersionNumber(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, std::string const &verstr);
+
+	bool PackageFromTask(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern);
+	bool PackageFromRegEx(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern);
+	bool PackageFromFnmatch(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern);
+	bool PackageFromPackageName(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string pattern);
+	bool PackageFromString(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string const &pattern);
+	bool PackageFromPattern(PackageContainerInterface * const pci, pkgCacheFile &Cache, std::string const &pattern);
+private:
+	void showTaskSelection(pkgCache::PkgIterator const &pkg, std::string const &pattern);
+	void showRegExSelection(pkgCache::PkgIterator const &pkg, std::string const &pattern);
+	void showFnmatchSelection(pkgCache::PkgIterator const &pkg, std::string const &pattern);
+	void showPatternSelection(pkgCache::PkgIterator const &pkg, std::string const &pattern);
+	void canNotFindTask(PackageContainerInterface *const pci, pkgCacheFile &Cache, std::string pattern);
+	void canNotFindRegEx(PackageContainerInterface *const pci, pkgCacheFile &Cache, std::string pattern);
+	void canNotFindFnmatch(PackageContainerInterface *const pci, pkgCacheFile &Cache, std::string pattern);
+	void canNotFindPackage(PackageContainerInterface *const pci, pkgCacheFile &Cache, std::string const &str);
+	void showSelectedVersion(pkgCache::PkgIterator const &Pkg, pkgCache::VerIterator const Ver,
+				 std::string const &ver, bool const verIsRel);
+	void canNotFindAllVer(VersionContainerInterface * const vci, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+	void canNotFindInstCandVer(VersionContainerInterface * const vci, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+	void canNotFindCandInstVer(VersionContainerInterface * const vci, pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+	pkgCache::VerIterator canNotFindNewestVer(pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+	pkgCache::VerIterator canNotFindCandidateVer(pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+	pkgCache::VerIterator canNotFindInstalledVer(pkgCacheFile &Cache, pkgCache::PkgIterator const &Pkg);
+
+	class Private;
+	Private * const d;
+};									/*}}}*/
+// Iterator templates for our Containers				/*{{{*/
+template<typename Interface, typename Master, typename iterator_type, typename container_iterator, typename container_value> class Container_iterator_base :
+   public Interface::template iterator_base<iterator_type>
+{
+protected:
+	container_iterator _iter;
+public:
+	using iterator_category = typename std::iterator_traits<container_iterator>::iterator_category;
+	using value_type = container_value;
+	using difference_type = std::ptrdiff_t;
+	using pointer = container_value*;
+	using reference = container_value&;
+	explicit Container_iterator_base(container_iterator const &i) : _iter(i) {}
+	inline container_value operator*(void) const { return static_cast<iterator_type const*>(this)->getType(); };
+	operator container_iterator(void) const { return _iter; }
+	inline iterator_type& operator++() { ++_iter; return static_cast<iterator_type&>(*this); }
+	inline iterator_type operator++(int) { iterator_type tmp(*this); operator++(); return tmp; }
+	inline iterator_type operator+(typename container_iterator::difference_type const &n) { return iterator_type(_iter + n); }
+	inline iterator_type operator+=(typename container_iterator::difference_type const &n) { _iter += n; return static_cast<iterator_type&>(*this); }
+	inline iterator_type& operator--() { --_iter;; return static_cast<iterator_type&>(*this); }
+	inline iterator_type operator--(int) { iterator_type tmp(*this); operator--(); return tmp; }
+	inline iterator_type operator-(typename container_iterator::difference_type const &n) { return iterator_type(_iter - n); }
+	inline typename container_iterator::difference_type operator-(iterator_type const &b) { return (_iter - b._iter); }
+	inline iterator_type operator-=(typename container_iterator::difference_type const &n) { _iter -= n; return static_cast<iterator_type&>(*this); }
+	inline bool operator!=(iterator_type const &i) const { return _iter != i._iter; }
+	inline bool operator==(iterator_type const &i) const { return _iter == i._iter; }
+	inline bool operator<(iterator_type const &i) const { return _iter < i._iter; }
+	inline bool operator>(iterator_type const &i) const { return _iter > i._iter; }
+	inline bool operator<=(iterator_type const &i) const { return _iter <= i._iter; }
+	inline bool operator>=(iterator_type const &i) const { return _iter >= i._iter; }
+	inline typename container_iterator::reference operator[](typename container_iterator::difference_type const &n) const { return _iter[n]; }
+
+	friend std::ostream& operator<<(std::ostream& out, iterator_type i) { return operator<<(out, *i); }
+	friend Master;
+};
+template<class Interface, class Container, class Master> class Container_const_iterator :
+   public Container_iterator_base<Interface, Master, Container_const_iterator<Interface, Container, Master>, typename Container::const_iterator, typename Container::value_type>
+{
+	typedef Container_const_iterator<Interface, Container, Master> iterator_type;
+	typedef typename Container::const_iterator container_iterator;
+public:
+	explicit Container_const_iterator(container_iterator i) :
+	   Container_iterator_base<Interface, Master, iterator_type, container_iterator, typename Container::value_type>(i) {}
+
+	inline typename Container::value_type getType(void) const { return *this->_iter; }
+};
+template<class Interface, class Container, class Master> class Container_iterator :
+   public Container_iterator_base<Interface, Master, Container_iterator<Interface, Container, Master>, typename Container::iterator, typename Container::value_type>
+{
+	typedef Container_iterator<Interface, Container, Master> iterator_type;
+	typedef typename Container::iterator container_iterator;
+public:
+	explicit Container_iterator(container_iterator const &i) :
+	   Container_iterator_base<Interface, Master, iterator_type, container_iterator, typename Container::value_type>(i) {}
+
+	operator typename Master::const_iterator() { return typename Master::const_iterator(this->_iter); }
+	inline typename Container::iterator::reference operator*(void) const { return *this->_iter; }
+
+	inline typename Container::value_type getType(void) const { return *this->_iter; }
+};
+template<class Interface, class Container, class Master> class Container_const_reverse_iterator :
+   public Container_iterator_base<Interface, Master, Container_const_reverse_iterator<Interface, Container, Master>, typename Container::const_reverse_iterator, typename Container::value_type>
+{
+	typedef Container_const_reverse_iterator<Interface, Container, Master> iterator_type;
+	typedef typename Container::const_reverse_iterator container_iterator;
+public:
+	explicit Container_const_reverse_iterator(container_iterator i) :
+	   Container_iterator_base<Interface, Master, iterator_type, container_iterator, typename Container::value_type>(i) {}
+
+	inline typename Container::value_type getType(void) const { return *this->_iter; }
+};
+template<class Interface, class Container, class Master> class Container_reverse_iterator :
+   public Container_iterator_base<Interface, Master, Container_reverse_iterator<Interface, Container, Master>, typename Container::reverse_iterator, typename Container::value_type>
+{
+	typedef Container_reverse_iterator<Interface, Container, Master> iterator_type;
+	typedef typename Container::reverse_iterator container_iterator;
+public:
+	explicit Container_reverse_iterator(container_iterator i) :
+	   Container_iterator_base<Interface, Master, iterator_type, container_iterator, typename Container::value_type>(i) {}
+
+	operator typename Master::const_iterator() { return typename Master::const_iterator(this->_iter); }
+	inline iterator_type& operator=(iterator_type const &i) { this->_iter = i._iter; return static_cast<iterator_type&>(*this); }
+	inline iterator_type& operator=(container_iterator const &i) { this->_iter = i; return static_cast<iterator_type&>(*this); }
+	inline typename Container::reverse_iterator::reference operator*(void) const { return *this->_iter; }
+
+	inline typename Container::value_type getType(void) const { return *this->_iter; }
+};
+									/*}}}*/
+class APT_PUBLIC PackageContainerInterface {					/*{{{*/
+/** \class PackageContainerInterface
+
+ * Interface ensuring that all operations can be executed on the yet to
+ * define concrete PackageContainer - access to all methods is possible,
+ * but in general the wrappers provided by the PackageContainer template
+ * are nicer to use.
+
+ * This class mostly protects use from the need to write all implementation
+ * of the methods working on containers in the template */
+public:
+	template<class Itr> class iterator_base {			/*{{{*/
+		pkgCache::PkgIterator getType() const { return static_cast<Itr const*>(this)->getType(); };
+	public:
+		operator pkgCache::PkgIterator(void) const { return getType(); }
+
+		inline const char *Name() const {return getType().Name(); }
+		inline std::string FullName(bool const Pretty) const { return getType().FullName(Pretty); }
+		inline std::string FullName() const { return getType().FullName(); }
+		inline bool Purge() const {return getType().Purge(); }
+		inline const char *Arch() const {return getType().Arch(); }
+		inline pkgCache::GrpIterator Group() const { return getType().Group(); }
+		inline pkgCache::VerIterator VersionList() const { return getType().VersionList(); }
+		inline pkgCache::VerIterator CurrentVer() const { return getType().CurrentVer(); }
+		inline pkgCache::DepIterator RevDependsList() const { return getType().RevDependsList(); }
+		inline pkgCache::PrvIterator ProvidesList() const { return getType().ProvidesList(); }
+		inline pkgCache::PkgIterator::OkState State() const { return getType().State(); }
+		inline const char *CurVersion() const { return getType().CurVersion(); }
+		inline pkgCache *Cache() const { return getType().Cache(); }
+		inline unsigned long Index() const {return getType().Index();}
+		// we have only valid iterators here
+		inline bool end() const { return false; }
+
+		inline pkgCache::Package const * operator->() const {return &*getType();}
+	};
+									/*}}}*/
+
+	virtual bool insert(pkgCache::PkgIterator const &P) = 0;
+	virtual bool empty() const = 0;
+	virtual void clear() = 0;
+	virtual size_t size() const = 0;
+
+	void setConstructor(CacheSetHelper::PkgSelector const by) { ConstructedBy = by; }
+	CacheSetHelper::PkgSelector getConstructor() const { return ConstructedBy; }
+	PackageContainerInterface();
+	explicit PackageContainerInterface(CacheSetHelper::PkgSelector const by);
+	PackageContainerInterface(PackageContainerInterface const &by);
+	PackageContainerInterface& operator=(PackageContainerInterface const &other);
+	virtual ~PackageContainerInterface();
+
+private:
+	CacheSetHelper::PkgSelector ConstructedBy;
+	void * const d;
+};
+									/*}}}*/
+template<class Container> class APT_PUBLIC PackageContainer : public PackageContainerInterface {/*{{{*/
+/** \class APT::PackageContainer
+
+    Simple wrapper around a container class like std::set to provide a similar
+    interface to a set of packages as to the complete set of all packages in the
+    pkgCache. */
+	Container _cont;
+public:									/*{{{*/
+	/** \brief smell like a pkgCache::PkgIterator */
+	typedef Container_const_iterator<PackageContainerInterface, Container, PackageContainer> const_iterator;
+	typedef Container_iterator<PackageContainerInterface, Container, PackageContainer> iterator;
+	typedef Container_const_reverse_iterator<PackageContainerInterface, Container, PackageContainer> const_reverse_iterator;
+	typedef Container_reverse_iterator<PackageContainerInterface, Container, PackageContainer> reverse_iterator;
+	typedef typename Container::value_type value_type;
+	typedef typename Container::pointer pointer;
+	typedef typename Container::const_pointer const_pointer;
+	typedef typename Container::reference reference;
+	typedef typename Container::const_reference const_reference;
+	typedef typename Container::difference_type difference_type;
+	typedef typename Container::size_type size_type;
+	typedef typename Container::allocator_type allocator_type;
+
+	bool insert(pkgCache::PkgIterator const &P) APT_OVERRIDE { if (P.end() == true) return false; _cont.insert(P); return true; }
+	template<class Cont> void insert(PackageContainer<Cont> const &pkgcont) { _cont.insert((typename Cont::const_iterator)pkgcont.begin(), (typename Cont::const_iterator)pkgcont.end()); }
+	void insert(const_iterator begin, const_iterator end) { _cont.insert(begin, end); }
+
+	bool empty() const APT_OVERRIDE { return _cont.empty(); }
+	void clear() APT_OVERRIDE { return _cont.clear(); }
+	size_t size() const APT_OVERRIDE { return _cont.size(); }
+#if __GNUC__ >= 5 || (__GNUC_MINOR__ >= 9 && __GNUC__ >= 4)
+	iterator erase( const_iterator pos ) { return iterator(_cont.erase(pos._iter)); }
+	iterator erase( const_iterator first, const_iterator last ) { return iterator(_cont.erase(first._iter, last._iter)); }
+#else
+	iterator erase( iterator pos ) { return iterator(_cont.erase(pos._iter)); }
+	iterator erase( iterator first, iterator last ) { return iterator(_cont.erase(first._iter, last._iter)); }
+#endif
+	const_iterator begin() const { return const_iterator(_cont.begin()); }
+	const_iterator end() const { return const_iterator(_cont.end()); }
+	const_reverse_iterator rbegin() const { return const_reverse_iterator(_cont.rbegin()); }
+	const_reverse_iterator rend() const { return const_reverse_iterator(_cont.rend()); }
+#if __cplusplus >= 201103L
+	const_iterator cbegin() const { return const_iterator(_cont.cbegin()); }
+	const_iterator cend() const { return const_iterator(_cont.cend()); }
+	const_reverse_iterator crbegin() const { return const_reverse_iterator(_cont.crbegin()); }
+	const_reverse_iterator crend() const { return const_reverse_iterator(_cont.crend()); }
+#endif
+	iterator begin() { return iterator(_cont.begin()); }
+	iterator end() { return iterator(_cont.end()); }
+	reverse_iterator rbegin() { return reverse_iterator(_cont.rbegin()); }
+	reverse_iterator rend() { return reverse_iterator(_cont.rend()); }
+	const_iterator find(pkgCache::PkgIterator const &P) const { return const_iterator(_cont.find(P)); }
+
+	PackageContainer() : PackageContainerInterface(CacheSetHelper::UNKNOWN) {}
+	explicit PackageContainer(CacheSetHelper::PkgSelector const &by) : PackageContainerInterface(by) {}
+	template<typename Itr> PackageContainer(Itr first, Itr last) : PackageContainerInterface(CacheSetHelper::UNKNOWN), _cont(first, last) {}
+#if __cplusplus >= 201103L
+	PackageContainer(std::initializer_list<value_type> list) : PackageContainerInterface(CacheSetHelper::UNKNOWN), _cont(list) {}
+	void push_back(value_type&& P) { _cont.emplace_back(std::move(P)); }
+	template<typename... Args> void emplace_back(Args&&... args) { _cont.emplace_back(std::forward<Args>(args)...); }
+#endif
+	void push_back(const value_type& P) { _cont.push_back(P); }
+
+	/** \brief sort all included versions with given comparer
+
+	    Some containers are sorted by default, some are not and can't be,
+	    but a few like std::vector can be sorted if need be, so this can be
+	    specialized in later on. The default is that this will fail though.
+	    Specifically, already sorted containers like std::set will return
+	    false as well as there is no easy way to check that the given comparer
+	    would sort in the same way the set is currently sorted
+
+	    \return \b true if the set was sorted, \b false if not. */
+	template<class Compare> bool sort(Compare /*Comp*/) { return false; }
+
+	/** \brief returns all packages in the cache who belong to the given task
+
+	    A simple helper responsible for search for all members of a task
+	    in the cache. Optional it prints a notice about the
+	    packages chosen cause of the given task.
+	    \param Cache the packages are in
+	    \param pattern name of the task
+	    \param helper responsible for error and message handling */
+	static PackageContainer FromTask(pkgCacheFile &Cache, std::string const &pattern, CacheSetHelper &helper) {
+		PackageContainer cont(CacheSetHelper::TASK);
+		helper.PackageFrom(CacheSetHelper::TASK, &cont, Cache, pattern);
+		return cont;
+	}
+	static PackageContainer FromTask(pkgCacheFile &Cache, std::string const &pattern) {
+		CacheSetHelper helper;
+		return FromTask(Cache, pattern, helper);
+	}
+
+	/** \brief returns all packages in the cache whose name matches a given pattern
+
+	    A simple helper responsible for executing a regular expression on all
+	    package names in the cache. Optional it prints a notice about the
+	    packages chosen cause of the given package.
+	    \param Cache the packages are in
+	    \param pattern regular expression for package names
+	    \param helper responsible for error and message handling */
+	static PackageContainer FromRegEx(pkgCacheFile &Cache, std::string const &pattern, CacheSetHelper &helper) {
+		PackageContainer cont(CacheSetHelper::REGEX);
+		helper.PackageFrom(CacheSetHelper::REGEX, &cont, Cache, pattern);
+		return cont;
+	}
+
+	static PackageContainer FromRegEx(pkgCacheFile &Cache, std::string const &pattern) {
+		CacheSetHelper helper;
+		return FromRegEx(Cache, pattern, helper);
+	}
+
+	static PackageContainer FromFnmatch(pkgCacheFile &Cache, std::string const &pattern, CacheSetHelper &helper) {
+		PackageContainer cont(CacheSetHelper::FNMATCH);
+		helper.PackageFrom(CacheSetHelper::FNMATCH, &cont, Cache, pattern);
+		return cont;
+	}
+	static PackageContainer FromFnMatch(pkgCacheFile &Cache, std::string const &pattern) {
+		CacheSetHelper helper;
+		return FromFnmatch(Cache, pattern, helper);
+	}
+
+	/** \brief returns all packages specified by a string
+
+	    \param Cache the packages are in
+	    \param pattern String the package name(s) should be extracted from
+	    \param helper responsible for error and message handling */
+	static PackageContainer FromString(pkgCacheFile &Cache, std::string const &pattern, CacheSetHelper &helper) {
+		PackageContainer cont;
+		helper.PackageFrom(CacheSetHelper::PACKAGENAME, &cont, Cache, pattern);
+		return cont;
+	}
+	static PackageContainer FromString(pkgCacheFile &Cache, std::string const &pattern) {
+		CacheSetHelper helper;
+		return FromString(Cache, pattern, helper);
+	}
+
+	/** \brief returns all packages specified on the commandline
+
+	    Get all package names from the commandline and executes regex's if needed.
+	    No special package command is supported, just plain names.
+	    \param Cache the packages are in
+	    \param cmdline Command line the package names should be extracted from
+	    \param helper responsible for error and message handling */
+	static PackageContainer FromCommandLine(pkgCacheFile &Cache, const char **cmdline, CacheSetHelper &helper) {
+		PackageContainer cont;
+		helper.PackageFromCommandLine(&cont, Cache, cmdline);
+		return cont;
+	}
+	static PackageContainer FromCommandLine(pkgCacheFile &Cache, const char **cmdline) {
+		CacheSetHelper helper;
+		return FromCommandLine(Cache, cmdline, helper);
+	}
+
+	/** \brief group packages by a action modifiers
+
+	    At some point it is needed to get from the same commandline
+	    different package sets grouped by a modifier. Take
+		apt-get install apt awesome-
+	    as an example.
+	    \param Cache the packages are in
+	    \param cmdline Command line the package names should be extracted from
+	    \param mods list of modifiers the method should accept
+	    \param fallback the default modifier group for a package
+	    \param helper responsible for error and message handling */
+	static std::map<unsigned short, PackageContainer> GroupedFromCommandLine(
+										 pkgCacheFile &Cache,
+										 const char **cmdline,
+										 std::list<CacheSetHelper::PkgModifier> const &mods,
+										 unsigned short const &fallback,
+										 CacheSetHelper &helper) {
+		std::map<unsigned short, PackageContainer> pkgsets;
+		for (const char **I = cmdline; *I != 0; ++I) {
+			unsigned short modID = fallback;
+			PackageContainer pkgset;
+			helper.PackageFromModifierCommandLine(modID, &pkgset, Cache, *I, mods);
+			pkgsets[modID].insert(pkgset);
+		}
+		return pkgsets;
+	}
+	static std::map<unsigned short, PackageContainer> GroupedFromCommandLine(
+										 pkgCacheFile &Cache,
+										 const char **cmdline,
+										 std::list<CacheSetHelper::PkgModifier> const &mods,
+										 unsigned short const &fallback) {
+		CacheSetHelper helper;
+		return GroupedFromCommandLine(Cache, cmdline,
+				mods, fallback, helper);
+	}
+									/*}}}*/
+};									/*}}}*/
+// various specialisations for PackageContainer				/*{{{*/
+template<> template<class Cont> void PackageContainer<std::list<pkgCache::PkgIterator> >::insert(PackageContainer<Cont> const &pkgcont) {
+	for (typename PackageContainer<Cont>::const_iterator p = pkgcont.begin(); p != pkgcont.end(); ++p)
+		_cont.push_back(*p);
+}
+#if __cplusplus >= 201103L
+template<> template<class Cont> void PackageContainer<std::forward_list<pkgCache::PkgIterator> >::insert(PackageContainer<Cont> const &pkgcont) {
+	for (typename PackageContainer<Cont>::const_iterator p = pkgcont.begin(); p != pkgcont.end(); ++p)
+		_cont.push_front(*p);
+}
+#endif
+template<> template<class Cont> void PackageContainer<std::deque<pkgCache::PkgIterator> >::insert(PackageContainer<Cont> const &pkgcont) {
+	for (typename PackageContainer<Cont>::const_iterator p = pkgcont.begin(); p != pkgcont.end(); ++p)
+		_cont.push_back(*p);
+}
+template<> template<class Cont> void PackageContainer<std::vector<pkgCache::PkgIterator> >::insert(PackageContainer<Cont> const &pkgcont) {
+	for (typename PackageContainer<Cont>::const_iterator p = pkgcont.begin(); p != pkgcont.end(); ++p)
+		_cont.push_back(*p);
+}
+// these are 'inline' as otherwise the linker has problems with seeing these untemplated
+// specializations again and again - but we need to see them, so that library users can use them
+template<> inline bool PackageContainer<std::list<pkgCache::PkgIterator> >::insert(pkgCache::PkgIterator const &P) {
+	if (P.end() == true)
+		return false;
+	_cont.push_back(P);
+	return true;
+}
+#if __cplusplus >= 201103L
+template<> inline bool PackageContainer<std::forward_list<pkgCache::PkgIterator> >::insert(pkgCache::PkgIterator const &P) {
+	if (P.end() == true)
+		return false;
+	_cont.push_front(P);
+	return true;
+}
+#endif
+template<> inline bool PackageContainer<std::deque<pkgCache::PkgIterator> >::insert(pkgCache::PkgIterator const &P) {
+	if (P.end() == true)
+		return false;
+	_cont.push_back(P);
+	return true;
+}
+template<> inline bool PackageContainer<std::vector<pkgCache::PkgIterator> >::insert(pkgCache::PkgIterator const &P) {
+	if (P.end() == true)
+		return false;
+	_cont.push_back(P);
+	return true;
+}
+template<> inline void PackageContainer<std::list<pkgCache::PkgIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator p = begin; p != end; ++p)
+		_cont.push_back(*p);
+}
+#if __cplusplus >= 201103L
+template<> inline void PackageContainer<std::forward_list<pkgCache::PkgIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator p = begin; p != end; ++p)
+		_cont.push_front(*p);
+}
+#endif
+template<> inline void PackageContainer<std::deque<pkgCache::PkgIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator p = begin; p != end; ++p)
+		_cont.push_back(*p);
+}
+template<> inline void PackageContainer<std::vector<pkgCache::PkgIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator p = begin; p != end; ++p)
+		_cont.push_back(*p);
+}
+#if APT_GCC_VERSION < 0x409
+template<> inline PackageContainer<std::set<pkgCache::PkgIterator> >::iterator PackageContainer<std::set<pkgCache::PkgIterator> >::erase(iterator i) {
+	_cont.erase(i._iter);
+	return end();
+}
+template<> inline PackageContainer<std::set<pkgCache::PkgIterator> >::iterator PackageContainer<std::set<pkgCache::PkgIterator> >::erase(iterator first, iterator last) {
+	_cont.erase(first, last);
+	return end();
+}
+#endif
+template<> template<class Compare> inline bool PackageContainer<std::vector<pkgCache::PkgIterator> >::sort(Compare Comp) {
+	std::sort(_cont.begin(), _cont.end(), Comp);
+	return true;
+}
+template<> template<class Compare> inline bool PackageContainer<std::list<pkgCache::PkgIterator> >::sort(Compare Comp) {
+	_cont.sort(Comp);
+	return true;
+}
+#if __cplusplus >= 201103L
+template<> template<class Compare> inline bool PackageContainer<std::forward_list<pkgCache::PkgIterator> >::sort(Compare Comp) {
+	_cont.sort(Comp);
+	return true;
+}
+#endif
+template<> template<class Compare> inline bool PackageContainer<std::deque<pkgCache::PkgIterator> >::sort(Compare Comp) {
+	std::sort(_cont.begin(), _cont.end(), Comp);
+	return true;
+}
+									/*}}}*/
+
+// class PackageUniverse - pkgCache as PackageContainerInterface	/*{{{*/
+/** \class PackageUniverse
+
+    Wraps around our usual pkgCache, so that it can be stuffed into methods
+    expecting a PackageContainer.
+
+    The wrapping is read-only in practice modeled by making erase and co
+    private methods. */
+class APT_PUBLIC PackageUniverse : public PackageContainerInterface {
+	pkgCache * const _cont;
+	void * const d;
+public:
+	class const_iterator : public APT::Container_iterator_base<APT::PackageContainerInterface, PackageUniverse, PackageUniverse::const_iterator, pkgCache::PkgIterator, pkgCache::PkgIterator>
+	{
+	public:
+	   explicit const_iterator(pkgCache::PkgIterator i):
+	      Container_iterator_base<APT::PackageContainerInterface, PackageUniverse, PackageUniverse::const_iterator, pkgCache::PkgIterator, pkgCache::PkgIterator>(i) {}
+
+	   inline pkgCache::PkgIterator getType(void) const { return _iter; }
+	};
+	typedef const_iterator iterator;
+	typedef pkgCache::PkgIterator value_type;
+	typedef typename pkgCache::PkgIterator* pointer;
+	typedef typename pkgCache::PkgIterator const* const_pointer;
+	typedef const pkgCache::PkgIterator& const_reference;
+	typedef const_reference reference;
+	typedef const_iterator::difference_type difference_type;
+	typedef std::make_unsigned<const_iterator::difference_type>::type size_type;
+
+
+	bool empty() const APT_OVERRIDE { return false; }
+	size_t size() const APT_OVERRIDE { return _cont->Head().PackageCount; }
+
+	const_iterator begin() const { return const_iterator(_cont->PkgBegin()); }
+	const_iterator end() const { return const_iterator(_cont->PkgEnd()); }
+	const_iterator cbegin() const { return const_iterator(_cont->PkgBegin()); }
+	const_iterator cend() const { return const_iterator(_cont->PkgEnd()); }
+	iterator begin() { return iterator(_cont->PkgBegin()); }
+	iterator end() { return iterator(_cont->PkgEnd()); }
+
+	pkgCache * data() const { return _cont; }
+
+	explicit PackageUniverse(pkgCache * const Owner);
+	explicit PackageUniverse(pkgCacheFile * const Owner);
+	virtual ~PackageUniverse();
+
+private:
+	APT_HIDDEN bool insert(pkgCache::PkgIterator const &) APT_OVERRIDE { return true; }
+	template<class Cont> APT_HIDDEN void insert(PackageContainer<Cont> const &) { }
+	APT_HIDDEN void insert(const_iterator, const_iterator) { }
+
+	APT_HIDDEN void clear() APT_OVERRIDE { }
+	APT_HIDDEN iterator erase( const_iterator pos );
+	APT_HIDDEN iterator erase( const_iterator first, const_iterator last );
+};
+									/*}}}*/
+typedef PackageContainer<std::set<pkgCache::PkgIterator> > PackageSet;
+#if __cplusplus >= 201103L
+typedef PackageContainer<std::unordered_set<pkgCache::PkgIterator> > PackageUnorderedSet;
+typedef PackageContainer<std::forward_list<pkgCache::PkgIterator> > PackageForwardList;
+#endif
+typedef PackageContainer<std::list<pkgCache::PkgIterator> > PackageList;
+typedef PackageContainer<std::deque<pkgCache::PkgIterator> > PackageDeque;
+typedef PackageContainer<std::vector<pkgCache::PkgIterator> > PackageVector;
+
+class APT_PUBLIC VersionContainerInterface {					/*{{{*/
+/** \class APT::VersionContainerInterface
+
+    Same as APT::PackageContainerInterface, just for Versions */
+public:
+	/** \brief smell like a pkgCache::VerIterator */
+	template<class Itr> class iterator_base {			/*{{{*/
+	   pkgCache::VerIterator getType() const { return static_cast<Itr const*>(this)->getType(); };
+	public:
+		operator pkgCache::VerIterator(void) { return getType(); }
+
+		inline pkgCache *Cache() const { return getType().Cache(); }
+		inline unsigned long Index() const {return getType().Index();}
+		inline int CompareVer(const pkgCache::VerIterator &B) const { return getType().CompareVer(B); }
+		inline const char *VerStr() const { return getType().VerStr(); }
+		inline const char *Section() const { return getType().Section(); }
+		inline const char *Arch() const { return getType().Arch(); }
+		inline pkgCache::PkgIterator ParentPkg() const { return getType().ParentPkg(); }
+		inline pkgCache::DescIterator DescriptionList() const { return getType().DescriptionList(); }
+		inline pkgCache::DescIterator TranslatedDescription() const { return getType().TranslatedDescription(); }
+		inline pkgCache::DepIterator DependsList() const { return getType().DependsList(); }
+		inline pkgCache::PrvIterator ProvidesList() const { return getType().ProvidesList(); }
+		inline pkgCache::VerFileIterator FileList() const { return getType().FileList(); }
+		inline bool Downloadable() const { return getType().Downloadable(); }
+		inline const char *PriorityType() const { return getType().PriorityType(); }
+		inline std::string RelStr() const { return getType().RelStr(); }
+		inline bool Automatic() const { return getType().Automatic(); }
+		inline pkgCache::VerFileIterator NewestFile() const { return getType().NewestFile(); }
+		// we have only valid iterators here
+		inline bool end() const { return false; }
+
+		inline pkgCache::Version const * operator->() const { return &*getType(); }
+	};
+									/*}}}*/
+
+	virtual bool insert(pkgCache::VerIterator const &V) = 0;
+	virtual bool empty() const = 0;
+	virtual void clear() = 0;
+	virtual size_t size() const = 0;
+
+	struct Modifier {
+		unsigned short const ID;
+		const char * const Alias;
+		enum Position { NONE, PREFIX, POSTFIX } const Pos;
+		enum CacheSetHelper::VerSelector const SelectVersion;
+		Modifier (unsigned short const &id, const char * const alias, Position const &pos,
+			  enum CacheSetHelper::VerSelector const select) : ID(id), Alias(alias), Pos(pos),
+			 SelectVersion(select) {}
+	};
+
+	static bool FromCommandLine(VersionContainerInterface * const vci, pkgCacheFile &Cache,
+				    const char **cmdline, CacheSetHelper::VerSelector const fallback,
+				    CacheSetHelper &helper);
+
+	static bool FromString(VersionContainerInterface * const vci, pkgCacheFile &Cache,
+			       std::string pkg, CacheSetHelper::VerSelector const fallback, CacheSetHelper &helper,
+			       bool const onlyFromName = false);
+
+	static bool FromPattern(VersionContainerInterface *const vci, pkgCacheFile &Cache,
+				std::string pkg, CacheSetHelper::VerSelector const fallback, CacheSetHelper &helper);
+
+	static bool FromPackage(VersionContainerInterface * const vci, pkgCacheFile &Cache,
+				pkgCache::PkgIterator const &P, CacheSetHelper::VerSelector const fallback,
+				CacheSetHelper &helper);
+
+	static bool FromModifierCommandLine(unsigned short &modID,
+					    VersionContainerInterface * const vci,
+					    pkgCacheFile &Cache, const char * cmdline,
+					    std::list<Modifier> const &mods,
+					    CacheSetHelper &helper);
+
+
+	static bool FromDependency(VersionContainerInterface * const vci,
+				   pkgCacheFile &Cache,
+				   pkgCache::DepIterator const &D,
+				   CacheSetHelper::VerSelector const selector,
+				   CacheSetHelper &helper);
+
+	VersionContainerInterface();
+	VersionContainerInterface(VersionContainerInterface const &other);
+	VersionContainerInterface& operator=(VersionContainerInterface const &other);
+	virtual ~VersionContainerInterface();
+private:
+	void * const d;
+
+protected:								/*{{{*/
+
+	/** \brief returns the candidate version of the package
+
+	    \param Cache to be used to query for information
+	    \param Pkg we want the candidate version from this package
+	    \param helper used in this container instance */
+	static pkgCache::VerIterator getCandidateVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, CacheSetHelper &helper);
+
+	/** \brief returns the installed version of the package
+
+	    \param Cache to be used to query for information
+	    \param Pkg we want the installed version from this package
+	    \param helper used in this container instance */
+	static pkgCache::VerIterator getInstalledVer(pkgCacheFile &Cache,
+		pkgCache::PkgIterator const &Pkg, CacheSetHelper &helper);
+									/*}}}*/
+};
+									/*}}}*/
+template<class Container> class APT_PUBLIC VersionContainer : public VersionContainerInterface {/*{{{*/
+/** \class APT::VersionContainer
+
+    Simple wrapper around a container class like std::set to provide a similar
+    interface to a set of versions as to the complete set of all versions in the
+    pkgCache. */
+	Container _cont;
+public:									/*{{{*/
+
+	typedef Container_const_iterator<VersionContainerInterface, Container, VersionContainer> const_iterator;
+	typedef Container_iterator<VersionContainerInterface, Container, VersionContainer> iterator;
+	typedef Container_const_reverse_iterator<VersionContainerInterface, Container, VersionContainer> const_reverse_iterator;
+	typedef Container_reverse_iterator<VersionContainerInterface, Container, VersionContainer> reverse_iterator;
+	typedef typename Container::value_type value_type;
+	typedef typename Container::pointer pointer;
+	typedef typename Container::const_pointer const_pointer;
+	typedef typename Container::reference reference;
+	typedef typename Container::const_reference const_reference;
+	typedef typename Container::difference_type difference_type;
+	typedef typename Container::size_type size_type;
+	typedef typename Container::allocator_type allocator_type;
+
+	bool insert(pkgCache::VerIterator const &V) APT_OVERRIDE { if (V.end() == true) return false; _cont.insert(V); return true; }
+	template<class Cont> void insert(VersionContainer<Cont> const &vercont) { _cont.insert((typename Cont::const_iterator)vercont.begin(), (typename Cont::const_iterator)vercont.end()); }
+	void insert(const_iterator begin, const_iterator end) { _cont.insert(begin, end); }
+	bool empty() const APT_OVERRIDE { return _cont.empty(); }
+	void clear() APT_OVERRIDE { return _cont.clear(); }
+	size_t size() const APT_OVERRIDE { return _cont.size(); }
+#if APT_GCC_VERSION >= 0x409
+	iterator erase( const_iterator pos ) { return iterator(_cont.erase(pos._iter)); }
+	iterator erase( const_iterator first, const_iterator last ) { return iterator(_cont.erase(first._iter, last._iter)); }
+#else
+	iterator erase( iterator pos ) { return iterator(_cont.erase(pos._iter)); }
+	iterator erase( iterator first, iterator last ) { return iterator(_cont.erase(first._iter, last._iter)); }
+#endif
+	const_iterator begin() const { return const_iterator(_cont.begin()); }
+	const_iterator end() const { return const_iterator(_cont.end()); }
+	const_reverse_iterator rbegin() const { return const_reverse_iterator(_cont.rbegin()); }
+	const_reverse_iterator rend() const { return const_reverse_iterator(_cont.rend()); }
+#if __cplusplus >= 201103L
+	const_iterator cbegin() const { return const_iterator(_cont.cbegin()); }
+	const_iterator cend() const { return const_iterator(_cont.cend()); }
+	const_reverse_iterator crbegin() const { return const_reverse_iterator(_cont.crbegin()); }
+	const_reverse_iterator crend() const { return const_reverse_iterator(_cont.crend()); }
+#endif
+	iterator begin() { return iterator(_cont.begin()); }
+	iterator end() { return iterator(_cont.end()); }
+	reverse_iterator rbegin() { return reverse_iterator(_cont.rbegin()); }
+	reverse_iterator rend() { return reverse_iterator(_cont.rend()); }
+	const_iterator find(pkgCache::VerIterator const &V) const { return const_iterator(_cont.find(V)); }
+
+	VersionContainer() : VersionContainerInterface() {}
+	template<typename Itr> VersionContainer(Itr first, Itr last) : VersionContainerInterface(), _cont(first, last) {}
+#if __cplusplus >= 201103L
+	VersionContainer(std::initializer_list<value_type> list) : VersionContainerInterface(), _cont(list) {}
+	void push_back(value_type&& P) { _cont.emplace_back(std::move(P)); }
+	template<typename... Args> void emplace_back(Args&&... args) { _cont.emplace_back(std::forward<Args>(args)...); }
+#endif
+	void push_back(const value_type& P) { _cont.push_back(P); }
+
+	/** \brief sort all included versions with given comparer
+
+	    Some containers are sorted by default, some are not and can't be,
+	    but a few like std::vector can be sorted if need be, so this can be
+	    specialized in later on. The default is that this will fail though.
+	    Specifically, already sorted containers like std::set will return
+	    false as well as there is no easy way to check that the given comparer
+	    would sort in the same way the set is currently sorted
+
+	    \return \b true if the set was sorted, \b false if not. */
+	template<class Compare> bool sort(Compare /*Comp*/) { return false; }
+
+	/** \brief returns all versions specified on the commandline
+
+	    Get all versions from the commandline, uses given default version if
+	    non specifically requested  and executes regex's if needed on names.
+	    \param Cache the packages and versions are in
+	    \param cmdline Command line the versions should be extracted from
+	    \param fallback version specification
+	    \param helper responsible for error and message handling */
+	static VersionContainer FromCommandLine(pkgCacheFile &Cache, const char **cmdline,
+			CacheSetHelper::VerSelector const fallback, CacheSetHelper &helper) {
+		VersionContainer vercon;
+		VersionContainerInterface::FromCommandLine(&vercon, Cache, cmdline, fallback, helper);
+		return vercon;
+	}
+	static VersionContainer FromCommandLine(pkgCacheFile &Cache, const char **cmdline,
+			CacheSetHelper::VerSelector const fallback) {
+		CacheSetHelper helper;
+		return FromCommandLine(Cache, cmdline, fallback, helper);
+	}
+	static VersionContainer FromCommandLine(pkgCacheFile &Cache, const char **cmdline) {
+		return FromCommandLine(Cache, cmdline, CacheSetHelper::CANDINST);
+	}
+	static VersionContainer FromString(pkgCacheFile &Cache, std::string const &pkg,
+			CacheSetHelper::VerSelector const fallback, CacheSetHelper &helper,
+                                           bool const /*onlyFromName = false*/) {
+		VersionContainer vercon;
+		VersionContainerInterface::FromString(&vercon, Cache, pkg, fallback, helper);
+		return vercon;
+	}
+	static VersionContainer FromString(pkgCacheFile &Cache, std::string pkg,
+			CacheSetHelper::VerSelector const fallback) {
+		CacheSetHelper helper;
+		return FromString(Cache, pkg, fallback, helper);
+	}
+	static VersionContainer FromString(pkgCacheFile &Cache, std::string pkg) {
+		return FromString(Cache, pkg, CacheSetHelper::CANDINST);
+	}
+
+
+	/** \brief returns all versions specified for the package
+
+	    \param Cache the package and versions are in
+	    \param P the package in question
+	    \param fallback the version(s) you want to get
+	    \param helper the helper used for display and error handling */
+	static VersionContainer FromPackage(pkgCacheFile &Cache, pkgCache::PkgIterator const &P,
+		CacheSetHelper::VerSelector const fallback, CacheSetHelper &helper) {
+		VersionContainer vercon;
+		VersionContainerInterface::FromPackage(&vercon, Cache, P, fallback, helper);
+		return vercon;
+	}
+	static VersionContainer FromPackage(pkgCacheFile &Cache, pkgCache::PkgIterator const &P,
+					    CacheSetHelper::VerSelector const fallback) {
+		CacheSetHelper helper;
+		return FromPackage(Cache, P, fallback, helper);
+	}
+	static VersionContainer FromPackage(pkgCacheFile &Cache, pkgCache::PkgIterator const &P) {
+		return FromPackage(Cache, P, CacheSetHelper::CANDIDATE);
+	}
+
+	static std::map<unsigned short, VersionContainer> GroupedFromCommandLine(
+										 pkgCacheFile &Cache,
+										 const char **cmdline,
+										 std::list<Modifier> const &mods,
+										 unsigned short const fallback,
+										 CacheSetHelper &helper) {
+		std::map<unsigned short, VersionContainer> versets;
+		for (const char **I = cmdline; *I != 0; ++I) {
+			unsigned short modID = fallback;
+			VersionContainer verset;
+			VersionContainerInterface::FromModifierCommandLine(modID, &verset, Cache, *I, mods, helper);
+			versets[modID].insert(verset);
+		}
+		return versets;
+
+	}
+	static std::map<unsigned short, VersionContainer> GroupedFromCommandLine(
+		pkgCacheFile &Cache, const char **cmdline,
+		std::list<Modifier> const &mods,
+		unsigned short const fallback) {
+		CacheSetHelper helper;
+		return GroupedFromCommandLine(Cache, cmdline,
+				mods, fallback, helper);
+	}
+
+	static VersionContainer FromDependency(pkgCacheFile &Cache, pkgCache::DepIterator const &D,
+					       CacheSetHelper::VerSelector const selector, CacheSetHelper &helper) {
+		VersionContainer vercon;
+		VersionContainerInterface::FromDependency(&vercon, Cache, D, selector, helper);
+		return vercon;
+	}
+	static VersionContainer FromDependency(pkgCacheFile &Cache, pkgCache::DepIterator const &D,
+					       CacheSetHelper::VerSelector const selector) {
+		CacheSetHelper helper;
+		return FromDependency(Cache, D, selector, helper);
+	}
+	static VersionContainer FromDependency(pkgCacheFile &Cache, pkgCache::DepIterator const &D) {
+		return FromDependency(Cache, D, CacheSetHelper::CANDIDATE);
+	}
+									/*}}}*/
+};									/*}}}*/
+// various specialisations for VersionContainer				/*{{{*/
+template<> template<class Cont> void VersionContainer<std::list<pkgCache::VerIterator> >::insert(VersionContainer<Cont> const &vercont) {
+	for (typename VersionContainer<Cont>::const_iterator v = vercont.begin(); v != vercont.end(); ++v)
+		_cont.push_back(*v);
+}
+#if __cplusplus >= 201103L
+template<> template<class Cont> void VersionContainer<std::forward_list<pkgCache::VerIterator> >::insert(VersionContainer<Cont> const &vercont) {
+	for (typename VersionContainer<Cont>::const_iterator v = vercont.begin(); v != vercont.end(); ++v)
+		_cont.push_front(*v);
+}
+#endif
+template<> template<class Cont> void VersionContainer<std::deque<pkgCache::VerIterator> >::insert(VersionContainer<Cont> const &vercont) {
+	for (typename VersionContainer<Cont>::const_iterator v = vercont.begin(); v != vercont.end(); ++v)
+		_cont.push_back(*v);
+}
+template<> template<class Cont> void VersionContainer<std::vector<pkgCache::VerIterator> >::insert(VersionContainer<Cont> const &vercont) {
+	for (typename VersionContainer<Cont>::const_iterator v = vercont.begin(); v != vercont.end(); ++v)
+		_cont.push_back(*v);
+}
+// these are 'inline' as otherwise the linker has problems with seeing these untemplated
+// specializations again and again - but we need to see them, so that library users can use them
+template<> inline bool VersionContainer<std::list<pkgCache::VerIterator> >::insert(pkgCache::VerIterator const &V) {
+	if (V.end() == true)
+		return false;
+	_cont.push_back(V);
+	return true;
+}
+#if __cplusplus >= 201103L
+template<> inline bool VersionContainer<std::forward_list<pkgCache::VerIterator> >::insert(pkgCache::VerIterator const &V) {
+	if (V.end() == true)
+		return false;
+	_cont.push_front(V);
+	return true;
+}
+#endif
+template<> inline bool VersionContainer<std::deque<pkgCache::VerIterator> >::insert(pkgCache::VerIterator const &V) {
+	if (V.end() == true)
+		return false;
+	_cont.push_back(V);
+	return true;
+}
+template<> inline bool VersionContainer<std::vector<pkgCache::VerIterator> >::insert(pkgCache::VerIterator const &V) {
+	if (V.end() == true)
+		return false;
+	_cont.push_back(V);
+	return true;
+}
+template<> inline void VersionContainer<std::list<pkgCache::VerIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator v = begin; v != end; ++v)
+		_cont.push_back(*v);
+}
+#if __cplusplus >= 201103L
+template<> inline void VersionContainer<std::forward_list<pkgCache::VerIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator v = begin; v != end; ++v)
+		_cont.push_front(*v);
+}
+#endif
+template<> inline void VersionContainer<std::deque<pkgCache::VerIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator v = begin; v != end; ++v)
+		_cont.push_back(*v);
+}
+template<> inline void VersionContainer<std::vector<pkgCache::VerIterator> >::insert(const_iterator begin, const_iterator end) {
+	for (const_iterator v = begin; v != end; ++v)
+		_cont.push_back(*v);
+}
+#if APT_GCC_VERSION < 0x409
+template<> inline VersionContainer<std::set<pkgCache::VerIterator> >::iterator VersionContainer<std::set<pkgCache::VerIterator> >::erase(iterator i) {
+	_cont.erase(i._iter);
+	return end();
+}
+template<> inline VersionContainer<std::set<pkgCache::VerIterator> >::iterator VersionContainer<std::set<pkgCache::VerIterator> >::erase(iterator first, iterator last) {
+	_cont.erase(first, last);
+	return end();
+}
+#endif
+template<> template<class Compare> inline bool VersionContainer<std::vector<pkgCache::VerIterator> >::sort(Compare Comp) {
+	std::sort(_cont.begin(), _cont.end(), Comp);
+	return true;
+}
+template<> template<class Compare> inline bool VersionContainer<std::list<pkgCache::VerIterator> >::sort(Compare Comp) {
+	_cont.sort(Comp);
+	return true;
+}
+#if __cplusplus >= 201103L
+template<> template<class Compare> inline bool VersionContainer<std::forward_list<pkgCache::VerIterator> >::sort(Compare Comp) {
+	_cont.sort(Comp);
+	return true;
+}
+#endif
+template<> template<class Compare> inline bool VersionContainer<std::deque<pkgCache::VerIterator> >::sort(Compare Comp) {
+	std::sort(_cont.begin(), _cont.end(), Comp);
+	return true;
+}
+									/*}}}*/
+
+typedef VersionContainer<std::set<pkgCache::VerIterator> > VersionSet;
+#if __cplusplus >= 201103L
+typedef VersionContainer<std::unordered_set<pkgCache::VerIterator> > VersionUnorderedSet;
+typedef VersionContainer<std::forward_list<pkgCache::VerIterator> > VersionForwardList;
+#endif
+typedef VersionContainer<std::list<pkgCache::VerIterator> > VersionList;
+typedef VersionContainer<std::deque<pkgCache::VerIterator> > VersionDeque;
+typedef VersionContainer<std::vector<pkgCache::VerIterator> > VersionVector;
+}
+#endif
diff --git a/apt-pkg/cdrom.cc b/apt-pkg/cdrom.cc
new file mode 100644
index 0000000..ea10d10
--- /dev/null
+++ b/apt-pkg/cdrom.cc
@@ -0,0 +1,989 @@
+/*
+ */
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cdrom.h>
+#include <apt-pkg/cdromutl.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexcopy.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <dirent.h>
+#include <dlfcn.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+
+#ifdef HAVE_UDEV
+#include <libudev.h>
+#endif
+
+using namespace std;
+
+// FindPackages - Find the package files on the CDROM			/*{{{*/
+// ---------------------------------------------------------------------
+/* We look over the cdrom for package files. This is a recursive
+   search that short circuits when it his a package file in the dir.
+   This speeds it up greatly as the majority of the size is in the
+   binary-* sub dirs. */
+bool pkgCdrom::FindPackages(string CD,
+			    vector<string> &List,
+			    vector<string> &SList, 
+			    vector<string> &SigList,
+			    vector<string> &TransList,
+			    string &InfoDir, pkgCdromStatus *log,
+			    unsigned int Depth)
+{
+   static ino_t Inodes[9];
+   DIR *D;
+
+   // if we have a look we "pulse" now
+   if(log)
+      log->Update();
+
+   if (Depth >= 7)
+      return true;
+
+   if (CD[CD.length()-1] != '/')
+      CD += '/';   
+
+   if (chdir(CD.c_str()) != 0)
+      return _error->Errno("chdir","Unable to change to %s",CD.c_str());
+
+   // Look for a .disk subdirectory
+   if (InfoDir.empty() == true)
+   {
+      if (DirectoryExists(".disk") == true)
+	 InfoDir = InfoDir + CD + ".disk/";
+   }
+
+   // Don't look into directories that have been marked to ignore.
+   if (RealFileExists(".aptignr") == true)
+      return true;
+
+   /* Check _first_ for a signature file as apt-cdrom assumes that all files
+      under a Packages/Source file are in control of that file and stops 
+      the scanning
+   */
+   if (RealFileExists("Release.gpg") == true || RealFileExists("InRelease") == true)
+   {
+      SigList.push_back(CD);
+   }
+
+   /* Aha! We found some package files. We assume that everything under 
+      this dir is controlled by those package files so we don't look down
+      anymore */
+   std::vector<APT::Configuration::Compressor> const compressor = APT::Configuration::getCompressors();
+   for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
+	c != compressor.end(); ++c)
+   {
+      if (RealFileExists(std::string("Packages").append(c->Extension).c_str()) == false)
+	 continue;
+
+      if (_config->FindB("Debug::aptcdrom",false) == true)
+	 std::clog << "Found Packages in " << CD << std::endl;
+      List.push_back(CD);
+
+      // Continue down if thorough is given
+      if (_config->FindB("APT::CDROM::Thorough",false) == false)
+	 return true;
+      break;
+   }
+   for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
+	c != compressor.end(); ++c)
+   {
+      if (RealFileExists(std::string("Sources").append(c->Extension).c_str()) == false)
+	 continue;
+
+      if (_config->FindB("Debug::aptcdrom",false) == true)
+	 std::clog << "Found Sources in " << CD << std::endl;
+      SList.push_back(CD);
+
+      // Continue down if thorough is given
+      if (_config->FindB("APT::CDROM::Thorough",false) == false)
+	 return true;
+      break;
+   }
+
+   // see if we find translation indices
+   if (DirectoryExists("i18n") == true)
+   {
+      D = opendir("i18n");
+      for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+      {
+	 if(strncmp(Dir->d_name, "Translation-", strlen("Translation-")) != 0)
+	    continue;
+	 string file = Dir->d_name;
+	 for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
+	      c != compressor.end(); ++c)
+	 {
+	    string fileext = flExtension(file);
+	    if (file == fileext)
+	       fileext.clear();
+	    else if (fileext.empty() == false)
+	       fileext = "." + fileext;
+
+	    if (c->Extension == fileext)
+	    {
+	       if (_config->FindB("Debug::aptcdrom",false) == true)
+		  std::clog << "Found translation " << Dir->d_name << " in " << CD << "i18n/" << std::endl;
+	       file.erase(file.size() - fileext.size());
+	       TransList.push_back(CD + "i18n/" + file);
+	       break;
+	    }
+	 }
+      }
+      closedir(D);
+   }
+
+   D = opendir(".");
+   if (D == 0)
+      return _error->Errno("opendir","Unable to read %s",CD.c_str());
+   
+   // Run over the directory
+   for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+   {
+      // Skip some files..
+      if (strcmp(Dir->d_name,".") == 0 ||
+	  strcmp(Dir->d_name,"..") == 0 ||
+	  strcmp(Dir->d_name,".disk") == 0 ||
+          strcmp(Dir->d_name,"debian-installer") == 0)
+	 continue;
+
+      // See if the name is a sub directory
+      struct stat Buf;
+      if (stat(Dir->d_name,&Buf) != 0)
+	 continue;      
+      
+      if (S_ISDIR(Buf.st_mode) == 0)
+	 continue;
+      
+      unsigned int I;
+      for (I = 0; I != Depth; I++)
+	 if (Inodes[I] == Buf.st_ino)
+	    break;
+      if (I != Depth)
+	 continue;
+      
+      // Store the inodes weve seen
+      Inodes[Depth] = Buf.st_ino;
+
+      // Descend
+      if (FindPackages(CD + Dir->d_name,List,SList,SigList,TransList,InfoDir,log,Depth+1) == false)
+	 break;
+
+      if (chdir(CD.c_str()) != 0)
+      {
+	 _error->Errno("chdir","Unable to change to %s", CD.c_str());
+	 closedir(D);
+	 return false;
+      }
+   };
+
+   closedir(D);
+   
+   return !_error->PendingError();
+}
+									/*}}}*/
+// Score - We compute a 'score' for a path				/*{{{*/
+// ---------------------------------------------------------------------
+/* Paths are scored based on how close they come to what I consider
+   normal. That is ones that have 'dist' 'stable' 'testing' will score
+   higher than ones without. */
+int pkgCdrom::Score(string Path)
+{
+   int Res = 0;
+   if (Path.find("stable/") != string::npos)
+      Res += 29;
+   if (Path.find("/binary-") != string::npos)
+      Res += 20;
+   if (Path.find("testing/") != string::npos)
+      Res += 28;
+   if (Path.find("unstable/") != string::npos)
+      Res += 27;
+   if (Path.find("/dists/") != string::npos)
+      Res += 40;
+   if (Path.find("/main/") != string::npos)
+      Res += 20;
+   if (Path.find("/contrib/") != string::npos)
+      Res += 20;
+   if (Path.find("/non-free/") != string::npos)
+      Res += 20;
+   if (Path.find("/non-free-firmware/") != string::npos)
+      Res += 20;
+   if (Path.find("/non-US/") != string::npos)
+      Res += 20;
+   if (Path.find("/source/") != string::npos)
+      Res += 10;
+   if (Path.find("/debian/") != string::npos)
+      Res -= 10;
+
+   // check for symlinks in the patch leading to the actual file
+   // a symlink gets a big penalty
+   struct stat Buf;
+   string statPath = flNotFile(Path);
+   string cdromPath = _config->FindDir("Acquire::cdrom::mount");
+   while(statPath != cdromPath && statPath != "./") {
+      statPath.resize(statPath.size()-1);  // remove the trailing '/'
+      if (lstat(statPath.c_str(),&Buf) == 0) {
+        if(S_ISLNK(Buf.st_mode)) {
+           Res -= 60;
+           break;
+        }
+      }
+      statPath = flNotFile(statPath); // descent
+   }
+
+   return Res;
+}
+									/*}}}*/
+// DropBinaryArch - Dump dirs with a string like /binary-<foo>/		/*{{{*/
+// ---------------------------------------------------------------------
+/* Here we drop everything that is not this machines arch */
+bool pkgCdrom::DropBinaryArch(vector<string> &List)
+{
+
+   for (unsigned int I = 0; I < List.size(); I++)
+   {
+      const char *Str = List[I].c_str();
+      const char *Start, *End;
+      if ((Start = strstr(Str,"/binary-")) == 0)
+	 continue;
+
+      // Between Start and End is the architecture
+      Start += 8;
+      if ((End = strstr(Start,"/")) != 0 && Start != End &&
+          APT::Configuration::checkArchitecture(string(Start, End)) == true)
+	 continue; // okay, architecture is accepted
+
+      // not accepted -> Erase it
+      List.erase(List.begin() + I);
+      --I; // the next entry is at the same index after the erase
+   }
+   
+   return true;
+}
+									/*}}}*/
+// DropTranslation - Dump unwanted Translation-<lang> files		/*{{{*/
+// ---------------------------------------------------------------------
+/* Here we drop everything that is not configured in Acquire::Languages */
+bool pkgCdrom::DropTranslation(vector<string> &List)
+{
+   for (unsigned int I = 0; I < List.size(); I++)
+   {
+      const char *Start;
+      if ((Start = strstr(List[I].c_str(), "/Translation-")) == NULL)
+	 continue;
+      Start += strlen("/Translation-");
+
+      if (APT::Configuration::checkLanguage(Start, true) == true)
+	 continue;
+
+      // not accepted -> Erase it
+      List.erase(List.begin() + I);
+      --I; // the next entry is at the same index after the erase
+   }
+
+   return true;
+}
+									/*}}}*/
+// DropRepeats - Drop repeated files resulting from symlinks		/*{{{*/
+// ---------------------------------------------------------------------
+/* Here we go and stat every file that we found and strip dup inodes. */
+bool pkgCdrom::DropRepeats(vector<string> &List,const char *Name)
+{
+   bool couldFindAllFiles = true;
+   // Get a list of all the inodes
+   ino_t *Inodes = new ino_t[List.size()];
+   for (unsigned int I = 0; I != List.size(); ++I)
+   {
+      struct stat Buf;
+      bool found = false;
+
+      std::vector<APT::Configuration::Compressor> const compressor = APT::Configuration::getCompressors();
+      for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
+	   c != compressor.end(); ++c)
+      {
+	 std::string const filename = List[I] + Name + c->Extension;
+         if (stat(filename.c_str(), &Buf) != 0)
+	    continue;
+	 Inodes[I] = Buf.st_ino;
+	 found = true;
+	 break;
+      }
+
+      if (found == false)
+      {
+	 _error->Errno("stat","Failed to stat %s%s",List[I].c_str(), Name);
+	 couldFindAllFiles = false;
+	 Inodes[I] = 0;
+      }
+   }
+
+   // Look for dups
+   for (unsigned int I = 0; I != List.size(); I++)
+   {
+      if (Inodes[I] == 0)
+	 continue;
+      for (unsigned int J = I+1; J < List.size(); J++)
+      {
+	 // No match
+	 if (Inodes[J] == 0 || Inodes[J] != Inodes[I])
+	    continue;
+	 
+	 // We score the two paths.. and erase one
+	 int ScoreA = Score(List[I]);
+	 int ScoreB = Score(List[J]);
+	 if (ScoreA < ScoreB)
+	 {
+	    List[I] = string();
+	    break;
+	 }
+	 
+	 List[J] = string();
+      }
+   }  
+   delete[] Inodes;
+
+   // Wipe erased entries
+   for (unsigned int I = 0; I < List.size();)
+   {
+      if (List[I].empty() == false)
+	 I++;
+      else
+	 List.erase(List.begin()+I);
+   }
+   
+   return couldFindAllFiles;
+}
+									/*}}}*/
+// ReduceSourceList - Takes the path list and reduces it		/*{{{*/
+// ---------------------------------------------------------------------
+/* This takes the list of source list expressed entries and collects
+   similar ones to form a single entry for each dist */
+void pkgCdrom::ReduceSourcelist(string /*CD*/,vector<string> &List)
+{
+   sort(List.begin(),List.end());
+   
+   // Collect similar entries
+   for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      // Find a space..
+      string::size_type Space = (*I).find(' ');
+      if (Space == string::npos)
+	 continue;
+      string::size_type SSpace = (*I).find(' ',Space + 1);
+      if (SSpace == string::npos)
+	 continue;
+
+      string Word1 = string(*I,Space,SSpace-Space);
+      string Prefix = string(*I,0,Space);
+      string Component = string(*I,SSpace);
+      for (vector<string>::iterator J = List.begin(); J != I; ++J)
+      {
+	 // Find a space..
+	 string::size_type Space2 = (*J).find(' ');
+	 if (Space2 == string::npos)
+	    continue;
+	 string::size_type SSpace2 = (*J).find(' ',Space2 + 1);
+	 if (SSpace2 == string::npos)
+	    continue;
+	 
+	 if (string(*J,0,Space2) != Prefix)
+	    continue;
+	 if (string(*J,Space2,SSpace2-Space2) != Word1)
+	    continue;
+
+	 string Component2 = string(*J, SSpace2) + " ";
+	 if (Component2.find(Component + " ") == std::string::npos)
+	    *J += Component;
+	 I->clear();
+      }
+   }   
+
+   // Wipe erased entries
+   for (unsigned int I = 0; I < List.size();)
+   {
+      if (List[I].empty() == false)
+	 I++;
+      else
+	 List.erase(List.begin()+I);
+   }
+}
+									/*}}}*/
+// WriteDatabase - Write the CDROM Database file			/*{{{*/
+// ---------------------------------------------------------------------
+/* We rewrite the configuration class associated with the cdrom database. */
+bool pkgCdrom::WriteDatabase(Configuration &Cnf)
+{
+   string DFile = _config->FindFile("Dir::State::cdroms");
+   string NewFile = DFile + ".new";
+
+   RemoveFile("WriteDatabase", NewFile);
+   ofstream Out(NewFile.c_str());
+   if (!Out)
+      return _error->Errno("ofstream::ofstream",
+			   "Failed to open %s.new",DFile.c_str());
+   
+   /* Write out all of the configuration directives by walking the
+      configuration tree */
+   Cnf.Dump(Out, NULL, "%F \"%v\";\n", false);
+
+   Out.close();
+
+   if (FileExists(DFile) == true)
+      rename(DFile.c_str(), (DFile + '~').c_str());
+   if (rename(NewFile.c_str(),DFile.c_str()) != 0)
+      return _error->Errno("rename","Failed to rename %s.new to %s",
+			   DFile.c_str(),DFile.c_str());
+
+   return true;
+}
+									/*}}}*/
+// WriteSourceList - Write an updated sourcelist			/*{{{*/
+// ---------------------------------------------------------------------
+/* This reads the old source list and copies it into the new one. It 
+   appends the new CDROM entries just after the first block of comments.
+   This places them first in the file. It also removes any old entries
+   that were the same. */
+bool pkgCdrom::WriteSourceList(string Name,vector<string> &List,bool Source)
+{
+   if (List.empty() == true)
+      return true;
+
+   string File = _config->FindFile("Dir::Etc::sourcelist");
+
+   FileFd F(FileExists(File) ? File : "/dev/null", FileFd::ReadOnly);
+   if (not F.IsOpen() || F.Failed())
+      return _error->Errno("WriteSourceList", "Opening %s failed", File.c_str());
+
+   string NewFile = File + ".new";
+   RemoveFile("WriteSourceList", NewFile);
+   ofstream Out(NewFile.c_str());
+   if (!Out)
+      return _error->Errno("ofstream::ofstream",
+			   "Failed to open %s.new",File.c_str());
+
+   // Create a short uri without the path
+   string ShortURI = "cdrom:[" + Name + "]/";
+   string ShortURI2 = "cdrom:" + Name + "/";     // For Compatibility
+
+   string Type;
+   if (Source == true)
+      Type = "deb-src";
+   else
+      Type = "deb";
+
+   int CurLine = 0;
+   bool First = true;
+   std::string Buffer;
+   while (F.ReadLine(Buffer))
+   {
+      ++CurLine;
+      auto const Cleaned = APT::String::Strip(SubstVar(Buffer, "\t", "        "));
+
+      // Comment or blank
+      if (Cleaned.empty() || Cleaned[0] == '#')
+      {
+	 Out << Buffer << endl;
+	 continue;
+      }
+
+      if (First == true)
+      {
+	 for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+	 {
+	    string::size_type Space = (*I).find(' ');
+	    if (Space == string::npos)
+	       return _error->Error("Internal error");
+	    Out << Type << " cdrom:[" << Name << "]/" << string(*I,0,Space) <<
+	       " " << string(*I,Space+1) << endl;
+	 }
+      }
+      First = false;
+      
+      // Grok it
+      string cType;
+      string URI;
+      const char *C = Cleaned.c_str();
+      if (ParseQuoteWord(C,cType) == false ||
+	  ParseQuoteWord(C,URI) == false)
+      {
+	 Out << Buffer << endl;
+	 continue;
+      }
+
+      // Emit lines like this one
+      if (cType != Type || (string(URI,0,ShortURI.length()) != ShortURI &&
+	  string(URI,0,ShortURI.length()) != ShortURI2))
+      {
+	 Out << Buffer << endl;
+	 continue;
+      }      
+   }
+   
+   // Just in case the file was empty
+   if (First == true)
+   {
+      for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+      {
+	 string::size_type Space = (*I).find(' ');
+	 if (Space == string::npos)
+	    return _error->Error("Internal error");
+	 
+	 Out << "deb cdrom:[" << Name << "]/" << string(*I,0,Space) << 
+	    " " << string(*I,Space+1) << endl;
+      }
+   }
+   
+   Out.close();
+
+   rename(File.c_str(), (File + '~').c_str());
+   if (rename(NewFile.c_str(),File.c_str()) != 0)
+      return _error->Errno("rename","Failed to rename %s.new to %s",
+			   File.c_str(),File.c_str());
+   
+   return true;
+}
+									/*}}}*/
+bool pkgCdrom::UnmountCDROM(std::string const &CDROM, pkgCdromStatus * const log)/*{{{*/
+{
+   if (_config->FindB("APT::CDROM::NoMount",false) == true)
+      return true;
+   if (log != NULL)
+      log->Update(_("Unmounting CD-ROM...\n"), STEP_LAST);
+   return UnmountCdrom(CDROM);
+}
+									/*}}}*/
+bool pkgCdrom::MountAndIdentCDROM(Configuration &Database, std::string &CDROM, std::string &ident, pkgCdromStatus * const log, bool const interactive)/*{{{*/
+{
+   // Startup
+   CDROM = _config->FindDir("Acquire::cdrom::mount");
+   if (CDROM[0] == '.')
+      CDROM= SafeGetCWD() + '/' + CDROM;
+
+   if (log != NULL)
+   {
+      string msg;
+      log->SetTotal(STEP_LAST);
+      strprintf(msg, _("Using CD-ROM mount point %s\n"), CDROM.c_str());
+      log->Update(msg, STEP_PREPARE);
+   }
+
+   // Unmount the CD and get the user to put in the one they want
+   if (_config->FindB("APT::CDROM::NoMount", false) == false)
+   {
+      if (interactive == true)
+      {
+	 UnmountCDROM(CDROM, log);
+
+	 if(log != NULL)
+	 {
+	    log->Update(_("Waiting for disc...\n"), STEP_WAIT);
+	    if(!log->ChangeCdrom()) {
+	       // user aborted
+	       return false;
+	    }
+	 }
+      }
+
+      // Mount the new CDROM
+      if(log != NULL)
+	 log->Update(_("Mounting CD-ROM...\n"), STEP_MOUNT);
+
+      if (MountCdrom(CDROM) == false)
+	 return _error->Error("Failed to mount the cdrom.");
+   }
+
+   if (IsMounted(CDROM) == false)
+      return _error->Error("Failed to mount the cdrom.");
+
+   // Hash the CD to get an ID
+   if (log != NULL)
+      log->Update(_("Identifying... "), STEP_IDENT);
+
+   if (IdentCdrom(CDROM,ident) == false)
+   {
+      ident = "";
+      if (log != NULL)
+	 log->Update("\n");
+      UnmountCDROM(CDROM, NULL);
+      return false;
+   }
+
+   if (log != NULL)
+   {
+      string msg;
+      strprintf(msg, "[%s]\n", ident.c_str());
+      log->Update(msg);
+   }
+
+   // Read the database
+   string DFile = _config->FindFile("Dir::State::cdroms");
+   if (FileExists(DFile) == true)
+   {
+      if (ReadConfigFile(Database,DFile) == false)
+      {
+	 UnmountCDROM(CDROM, NULL);
+	 return _error->Error("Unable to read the cdrom database %s",
+			      DFile.c_str());
+      }
+   }
+   return true;
+}
+									/*}}}*/
+bool pkgCdrom::Ident(string &ident, pkgCdromStatus *log)		/*{{{*/
+{
+   Configuration Database;
+   std::string CDROM;
+   if (MountAndIdentCDROM(Database, CDROM, ident, log, false) == false)
+      return false;
+
+   if (log != NULL)
+   {
+      string msg;
+      strprintf(msg, _("Stored label: %s\n"),
+	    Database.Find("CD::"+ident).c_str());
+      log->Update(msg);
+   }
+
+   // Unmount and finish
+   UnmountCDROM(CDROM, log);
+   return true;
+}
+									/*}}}*/
+bool pkgCdrom::Add(pkgCdromStatus *log)					/*{{{*/
+{
+   Configuration Database;
+   std::string ID, CDROM;
+   if (MountAndIdentCDROM(Database, CDROM, ID, log, true) == false)
+      return false;
+
+   if(log != NULL)
+      log->Update(_("Scanning disc for index files...\n"),STEP_SCAN);
+
+   // Get the CD structure
+   vector<string> List;
+   vector<string> SourceList;
+   vector<string> SigList;
+   vector<string> TransList;
+   string StartDir = SafeGetCWD();
+   string InfoDir;
+   if (FindPackages(CDROM,List,SourceList, SigList,TransList,InfoDir,log) == false)
+   {
+      if (log != NULL)
+	 log->Update("\n");
+      UnmountCDROM(CDROM, NULL);
+      return false;
+   }
+
+   if (chdir(StartDir.c_str()) != 0)
+   {
+      UnmountCDROM(CDROM, NULL);
+      return _error->Errno("chdir","Unable to change to %s", StartDir.c_str());
+   }
+
+   if (_config->FindB("Debug::aptcdrom",false) == true)
+   {
+      cout << "I found (binary):" << endl;
+      for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+	 cout << *I << endl;
+      cout << "I found (source):" << endl;
+      for (vector<string>::iterator I = SourceList.begin(); I != SourceList.end(); ++I)
+	 cout << *I << endl;
+      cout << "I found (Signatures):" << endl;
+      for (vector<string>::iterator I = SigList.begin(); I != SigList.end(); ++I)
+	 cout << *I << endl;
+   }   
+
+   //log->Update(_("Cleaning package lists..."), STEP_CLEAN);
+
+   // Fix up the list
+   DropBinaryArch(List);
+   DropRepeats(List,"Packages");
+   DropRepeats(SourceList,"Sources");
+   // FIXME: We ignore stat() errors here as we usually have only one of those in use
+   // This has little potential to drop 'valid' stat() errors as we know that one of these
+   // files need to exist, but it would be better if we would check it here
+   _error->PushToStack();
+   DropRepeats(SigList,"Release.gpg");
+   DropRepeats(SigList,"InRelease");
+   _error->RevertToStack();
+   DropRepeats(TransList,"");
+   if (_config->FindB("APT::CDROM::DropTranslation", true) == true)
+      DropTranslation(TransList);
+   if(log != NULL) {
+      string msg;
+      strprintf(msg, _("Found %zu package indexes, %zu source indexes, "
+		      "%zu translation indexes and %zu signatures\n"), 
+	       List.size(), SourceList.size(), TransList.size(),
+	       SigList.size());
+      log->Update(msg, STEP_SCAN);
+   }
+
+   if (List.empty() == true && SourceList.empty() == true) 
+   {
+      UnmountCDROM(CDROM, NULL);
+      return _error->Error(_("Unable to locate any package files, perhaps this is not a Debian Disc or the wrong architecture?"));
+   }
+
+   // Check if the CD is in the database
+   string Name;
+   if (Database.Exists("CD::" + ID) == false ||
+       _config->FindB("APT::CDROM::Rename",false) == true)
+   {
+      // Try to use the CDs label if at all possible
+      if (InfoDir.empty() == false &&
+	  FileExists(InfoDir + "/info") == true)
+      {
+	 ifstream F((InfoDir + "/info").c_str());
+	 if (F.good() == true)
+	    getline(F,Name);
+
+	 if (Name.empty() == false)
+	 {
+	    // Escape special characters
+	    string::iterator J = Name.begin();
+	    for (; J != Name.end(); ++J)
+	       if (*J == '"' || *J == ']' || *J == '[')
+		  *J = '_';
+	    
+	    if(log != NULL)
+	    {
+	       string msg;
+	       strprintf(msg, _("Found label '%s'\n"), Name.c_str());
+	       log->Update(msg);
+	    }
+	    Database.Set("CD::" + ID + "::Label",Name);
+	 }	 
+      }
+      
+      if (_config->FindB("APT::CDROM::Rename",false) == true ||
+	  Name.empty() == true)
+      {
+	 if(log == NULL) 
+         {
+	    UnmountCDROM(CDROM, NULL);
+	    return _error->Error("No disc name found and no way to ask for it");
+	 }
+
+	 while(true) {
+	    if(!log->AskCdromName(Name)) {
+	       // user canceld
+	       UnmountCDROM(CDROM, NULL);
+	       return false; 
+	    }
+	    cout << "Name: '" << Name << "'" << endl;
+
+	    if (Name.empty() == false &&
+		Name.find('"') == string::npos &&
+		Name.find('[') == string::npos &&
+		Name.find(']') == string::npos)
+	       break;
+	    log->Update(_("That is not a valid name, try again.\n"));
+	 }
+      }      
+   }
+   else
+      Name = Database.Find("CD::" + ID);
+
+   // Escape special characters
+   string::iterator J = Name.begin();
+   for (; J != Name.end(); ++J)
+      if (*J == '"' || *J == ']' || *J == '[')
+	 *J = '_';
+   
+   Database.Set("CD::" + ID,Name);
+   if(log != NULL)
+   {
+      string msg;
+      strprintf(msg, _("This disc is called: \n'%s'\n"), Name.c_str());
+      log->Update(msg);
+      log->Update(_("Copying package lists..."), STEP_COPY);
+   }
+
+   // check for existence and possibly create state directory for copying
+   string const listDir = _config->FindDir("Dir::State::lists");
+   string const partialListDir = listDir + "partial/";
+   mode_t const mode = umask(S_IWGRP | S_IWOTH);
+   bool const creation_fail = (CreateAPTDirectoryIfNeeded(_config->FindDir("Dir::State"), partialListDir) == false &&
+	 CreateAPTDirectoryIfNeeded(listDir, partialListDir) == false);
+   umask(mode);
+   if (creation_fail == true)
+   {
+      UnmountCDROM(CDROM, NULL);
+      return _error->Errno("cdrom", _("List directory %s is missing."), (listDir + "partial").c_str());
+   }
+
+   // take care of the signatures and copy them if they are ok
+   // (we do this before PackageCopy as it modifies "List" and "SourceList")
+   SigVerify SignVerify;
+   SignVerify.CopyAndVerify(CDROM, Name, SigList, List, SourceList);
+   
+   // Copy the package files to the state directory
+   PackageCopy Copy;
+   SourceCopy SrcCopy;
+   TranslationsCopy TransCopy;
+   if (Copy.CopyPackages(CDROM,Name,List, log) == false ||
+       SrcCopy.CopyPackages(CDROM,Name,SourceList, log) == false ||
+       TransCopy.CopyTranslations(CDROM,Name,TransList, log) == false)
+   {
+      UnmountCDROM(CDROM, NULL);
+      return false;
+   }
+
+   // reduce the List so that it takes less space in sources.list
+   ReduceSourcelist(CDROM,List);
+   ReduceSourcelist(CDROM,SourceList);
+
+   // Write the database and sourcelist
+   if (_config->FindB("APT::cdrom::NoAct",false) == false)
+   {
+      if (WriteDatabase(Database) == false)
+      {
+	 UnmountCDROM(CDROM, NULL);
+	 return false;
+      }
+
+      if(log != NULL)
+	 log->Update(_("Writing new source list\n"), STEP_WRITE);
+      if (WriteSourceList(Name,List,false) == false ||
+	  WriteSourceList(Name,SourceList,true) == false)
+      {
+	 UnmountCDROM(CDROM, NULL);
+	 return false;
+      }
+   }
+
+   // Print the sourcelist entries
+   if(log != NULL)
+      log->Update(_("Source list entries for this disc are:\n"));
+
+   for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      string::size_type Space = (*I).find(' ');
+      if (Space == string::npos)
+      {
+	 UnmountCDROM(CDROM, NULL);
+	 return _error->Error("Internal error");
+      }
+
+      if(log != NULL)
+      {
+	 stringstream msg;
+	 msg << "deb cdrom:[" << Name << "]/" << string(*I,0,Space) << 
+	    " " << string(*I,Space+1) << endl;
+	 log->Update(msg.str());
+      }
+   }
+
+   for (vector<string>::iterator I = SourceList.begin(); I != SourceList.end(); ++I)
+   {
+      string::size_type Space = (*I).find(' ');
+      if (Space == string::npos)
+      {
+	 UnmountCDROM(CDROM, NULL);
+	 return _error->Error("Internal error");
+      }
+
+      if(log != NULL) {
+	 stringstream msg;
+	 msg << "deb-src cdrom:[" << Name << "]/" << string(*I,0,Space) << 
+	    " " << string(*I,Space+1) << endl;
+	 log->Update(msg.str());
+      }
+   }
+
+   // Unmount and finish
+   UnmountCDROM(CDROM, log);
+   return true;
+}
+									/*}}}*/
+
+pkgUdevCdromDevices::pkgUdevCdromDevices() /*{{{*/
+    : d(NULL)
+{
+}
+									/*}}}*/
+// convenience interface, this will just call ScanForRemovable		/*{{{*/
+vector<CdromDevice> pkgUdevCdromDevices::Scan()
+{
+   bool CdromOnly = _config->FindB("APT::cdrom::CdromOnly", true);
+   return ScanForRemovable(CdromOnly);
+}
+									/*}}}*/
+vector<CdromDevice> pkgUdevCdromDevices::ScanForRemovable(bool CdromOnly)/*{{{*/
+{
+   vector<CdromDevice> cdrom_devices;
+#ifdef HAVE_UDEV
+   struct udev_enumerate *enumerate;
+   struct udev_list_entry *l, *devices;
+   struct udev *udev_ctx;
+
+   udev_ctx = udev_new();
+   enumerate = udev_enumerate_new (udev_ctx);
+   if (CdromOnly)
+      udev_enumerate_add_match_property(enumerate, "ID_CDROM", "1");
+   else {
+      udev_enumerate_add_match_sysattr(enumerate, "removable", "1");
+   }
+
+   udev_enumerate_scan_devices (enumerate);
+   devices = udev_enumerate_get_list_entry (enumerate);
+   for (l = devices; l != NULL; l = udev_list_entry_get_next (l))
+   {
+      CdromDevice cdrom;
+      struct udev_device *udevice;
+      udevice = udev_device_new_from_syspath (udev_enumerate_get_udev (enumerate), udev_list_entry_get_name (l));
+      if (udevice == NULL)
+	 continue;
+      const char* devnode = udev_device_get_devnode(udevice);
+
+      // try fstab_dir first
+      string mountpath;
+      const char* mp = udev_device_get_property_value(udevice, "FSTAB_DIR");
+      if (mp)
+         mountpath = string(mp);
+      else
+         mountpath = FindMountPointForDevice(devnode);
+
+      // fill in the struct
+      cdrom.DeviceName = string(devnode);
+      if (mountpath != "") {
+	 cdrom.MountPath = mountpath;
+	 string s = mountpath;
+	 cdrom.Mounted = IsMounted(s);
+      } else {
+	 cdrom.Mounted = false;
+	 cdrom.MountPath = "";
+      }
+      cdrom_devices.push_back(cdrom);
+   }
+#endif
+   return cdrom_devices;
+}
+									/*}}}*/
+
+pkgUdevCdromDevices::~pkgUdevCdromDevices()                             /*{{{*/
+{ 
+}
+									/*}}}*/
+
+pkgCdromStatus::pkgCdromStatus() : d(NULL), totalSteps(0) {}
+pkgCdromStatus::~pkgCdromStatus() {}
+
+pkgCdrom::pkgCdrom() : d(NULL) {}
+pkgCdrom::~pkgCdrom() {}
diff --git a/apt-pkg/cdrom.h b/apt-pkg/cdrom.h
new file mode 100644
index 0000000..d3fc771
--- /dev/null
+++ b/apt-pkg/cdrom.h
@@ -0,0 +1,110 @@
+#ifndef PKGLIB_CDROM_H
+#define PKGLIB_CDROM_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+#include <vector>
+
+#include <stddef.h>
+
+
+class Configuration;
+class OpProgress;
+
+class APT_PUBLIC pkgCdromStatus							/*{{{*/
+{
+   void * const d;
+ protected:
+   int totalSteps;
+
+ public:
+   pkgCdromStatus();
+   virtual ~pkgCdromStatus();
+
+   // total steps
+   virtual void SetTotal(int total) { totalSteps = total; };
+   // update steps, will be called regularly as a "pulse"
+   virtual void Update(std::string text="", int current=0) = 0;
+   
+   // ask for cdrom insert
+   virtual bool ChangeCdrom() = 0;
+   // ask for cdrom name
+   virtual bool AskCdromName(std::string &Name) = 0;
+   // Progress indicator for the Index rewriter
+   virtual OpProgress* GetOpProgress() {return NULL; };
+};
+									/*}}}*/
+class APT_PUBLIC pkgCdrom								/*{{{*/
+{
+ protected:
+   enum {
+      STEP_PREPARE = 1,
+      STEP_UNMOUNT,
+      STEP_WAIT,
+      STEP_MOUNT,
+      STEP_IDENT,
+      STEP_SCAN,
+      STEP_COPY,
+      STEP_WRITE,
+      STEP_UNMOUNT3,
+      STEP_LAST
+   };
+
+
+   bool FindPackages(std::string CD,
+		     std::vector<std::string> &List,
+		     std::vector<std::string> &SList, 
+		     std::vector<std::string> &SigList,
+		     std::vector<std::string> &TransList,
+		     std::string &InfoDir, pkgCdromStatus *log,
+		     unsigned int Depth = 0);
+   bool DropBinaryArch(std::vector<std::string> &List);
+   bool DropRepeats(std::vector<std::string> &List,const char *Name);
+   bool DropTranslation(std::vector<std::string> &List);
+   void ReduceSourcelist(std::string CD,std::vector<std::string> &List);
+   bool WriteDatabase(Configuration &Cnf);
+   bool WriteSourceList(std::string Name,std::vector<std::string> &List,bool Source);
+   int Score(std::string Path);
+
+ public:
+   bool Ident(std::string &ident, pkgCdromStatus *log);
+   bool Add(pkgCdromStatus *log);
+
+   pkgCdrom();
+   virtual ~pkgCdrom();
+
+ private:
+   void * const d;
+
+   APT_HIDDEN bool MountAndIdentCDROM(Configuration &Database, std::string &CDROM,
+	 std::string &ident, pkgCdromStatus * const log, bool const interactive);
+   APT_HIDDEN bool UnmountCDROM(std::string const &CDROM, pkgCdromStatus * const log);
+};
+									/*}}}*/
+
+
+// class that uses libudev to find cdrom/removable devices dynamically
+struct APT_PUBLIC CdromDevice							/*{{{*/
+{
+   std::string DeviceName;
+   bool Mounted;
+   std::string MountPath;
+};
+									/*}}}*/
+class APT_PUBLIC pkgUdevCdromDevices						/*{{{*/
+{
+   void * const d;
+ public:
+   pkgUdevCdromDevices();
+   virtual ~pkgUdevCdromDevices();
+
+   // convenience interface, this will just call ScanForRemovable
+   // with "APT::cdrom::CdromOnly"
+   std::vector<CdromDevice> Scan();
+
+   std::vector<CdromDevice> ScanForRemovable(bool CdromOnly);
+};
+									/*}}}*/
+
+#endif
diff --git a/apt-pkg/clean.cc b/apt-pkg/clean.cc
new file mode 100644
index 0000000..9dd56e6
--- /dev/null
+++ b/apt-pkg/clean.cc
@@ -0,0 +1,134 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Clean - Clean out downloaded directories
+   
+   ##################################################################### */
+									/*}}}*/
+// Includes								/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/clean.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/strutl.h>
+
+#include <string>
+#include <dirent.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+// ArchiveCleaner::Go - Perform smart cleanup of the archive		/*{{{*/
+// ---------------------------------------------------------------------
+/* Scan the directory for files to erase, we check the version information
+   against our database to see if it is interesting */
+bool pkgArchiveCleaner::Go(std::string Dir,pkgCache &Cache)
+{
+   bool CleanInstalled = _config->FindB("APT::Clean-Installed",true);
+
+   if(Dir == "/")
+      return _error->Error(_("Clean of %s is not supported"), Dir.c_str());
+
+   // non-existing directories are always clean
+   // we do not check for a directory explicitly to support symlinks
+   if (FileExists(Dir) == false)
+      return true;
+
+   int const dirfd = open(Dir.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+   if (dirfd == -1)
+      return _error->Errno("open",_("Unable to read %s"),Dir.c_str());
+   DIR * const D = fdopendir(dirfd);
+   if (D == nullptr)
+      return _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
+
+   for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+   {
+      // Skip some files..
+      if (strcmp(Dir->d_name, "lock") == 0 ||
+	  strcmp(Dir->d_name, "partial") == 0 ||
+	  strcmp(Dir->d_name, "auxfiles") == 0 ||
+	  strcmp(Dir->d_name, "lost+found") == 0 ||
+	  strcmp(Dir->d_name, ".") == 0 ||
+	  strcmp(Dir->d_name, "..") == 0)
+	 continue;
+
+      struct stat St;
+      if (fstatat(dirfd, Dir->d_name,&St, 0) != 0)
+      {
+	 _error->Errno("stat",_("Unable to stat %s."),Dir->d_name);
+	 closedir(D);
+	 return false;
+      }
+
+      // Grab the package name
+      const char *I = Dir->d_name;
+      for (; *I != 0 && *I != '_';I++);
+      if (*I != '_')
+	 continue;
+      std::string Pkg = DeQuoteString(std::string(Dir->d_name,I-Dir->d_name));
+
+      // Grab the version
+      const char *Start = I + 1;
+      for (I = Start; *I != 0 && *I != '_';I++);
+      if (*I != '_')
+	 continue;
+      std::string Ver = DeQuoteString(std::string(Start,I-Start));
+
+      // Grab the arch
+      Start = I + 1;
+      for (I = Start; *I != 0 && *I != '.' ;I++);
+      if (*I != '.')
+	 continue;
+      std::string const Arch = DeQuoteString(std::string(Start,I-Start));
+
+      // ignore packages of unconfigured architectures
+      if (APT::Configuration::checkArchitecture(Arch) == false)
+	 continue;
+
+      // Lookup the package
+      pkgCache::PkgIterator P = Cache.FindPkg(Pkg, Arch);
+      if (P.end() != true)
+      {
+	 pkgCache::VerIterator V = P.VersionList();
+	 for (; V.end() == false; ++V)
+	 {
+	    // See if we can fetch this version at all
+	    bool IsFetchable = false;
+	    for (pkgCache::VerFileIterator J = V.FileList(); 
+		 J.end() == false; ++J)
+	    {
+	       if (CleanInstalled == true &&
+		   J.File().Flagged(pkgCache::Flag::NotSource))
+		  continue;
+	       IsFetchable = true;
+	       break;
+	    }
+
+	    // See if this version matches the file
+	    if (IsFetchable == true && Ver == V.VerStr())
+	       break;
+	 }
+
+	 // We found a match, keep the file
+	 if (V.end() == false)
+	    continue;
+      }
+
+      Erase(dirfd, Dir->d_name, Pkg, Ver, St);
+   }
+   closedir(D);
+   return true;
+}
+									/*}}}*/
+
+pkgArchiveCleaner::pkgArchiveCleaner() : d(NULL) {}
+pkgArchiveCleaner::~pkgArchiveCleaner() {}
diff --git a/apt-pkg/clean.h b/apt-pkg/clean.h
new file mode 100644
index 0000000..21b90e5
--- /dev/null
+++ b/apt-pkg/clean.h
@@ -0,0 +1,38 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Clean - Clean out downloaded directories
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef APTPKG_CLEAN_H
+#define APTPKG_CLEAN_H
+
+
+#include <string>
+
+#include <apt-pkg/macros.h>
+
+class pkgCache;
+
+class APT_PUBLIC pkgArchiveCleaner
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   protected:
+   virtual void Erase(int const dirfd, char const * const File,
+	 std::string const &Pkg,std::string const &Ver,
+	 struct stat const &St) = 0;
+
+   public:
+
+   bool Go(std::string Dir,pkgCache &Cache);
+
+   pkgArchiveCleaner();
+   virtual ~pkgArchiveCleaner();
+};
+
+
+#endif
diff --git a/apt-pkg/contrib/arfile.cc b/apt-pkg/contrib/arfile.cc
new file mode 100644
index 0000000..6d4a1f1
--- /dev/null
+++ b/apt-pkg/contrib/arfile.cc
@@ -0,0 +1,179 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   AR File - Handle an 'AR' archive
+   
+   AR Archives have plain text headers at the start of each file
+   section. The headers are aligned on a 2 byte boundary.
+   
+   Information about the structure of AR files can be found in ar(5)
+   on a BSD system, or in the binutils source.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/arfile.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <string>
+#include <string.h>
+#include <sys/types.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+struct ARArchive::MemberHeader
+{
+   char Name[16];
+   char MTime[12];
+   char UID[6];
+   char GID[6];
+   char Mode[8];
+   char Size[10];
+   char Magic[2];
+};
+
+// ARArchive::ARArchive - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ARArchive::ARArchive(FileFd &File) : List(0), File(File)
+{
+   LoadHeaders();
+}
+									/*}}}*/
+// ARArchive::~ARArchive - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ARArchive::~ARArchive()
+{
+   while (List != 0)
+   {
+      Member *Tmp = List;
+      List = List->Next;
+      delete Tmp;
+   }   
+}
+									/*}}}*/
+// ARArchive::LoadHeaders - Load the headers from each file		/*{{{*/
+// ---------------------------------------------------------------------
+/* AR files are structured with a 8 byte magic string followed by a 60
+   byte plain text header then the file data, another header, data, etc */
+bool ARArchive::LoadHeaders()
+{
+   off_t Left = File.Size();
+   
+   // Check the magic byte
+   char Magic[8];
+   if (File.Read(Magic,sizeof(Magic)) == false)
+      return false;
+   if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
+      return _error->Error(_("Invalid archive signature"));
+   Left -= sizeof(Magic);
+   
+   // Read the member list
+   while (Left > 0)
+   {
+      MemberHeader Head;
+      if (File.Read(&Head,sizeof(Head)) == false)
+	 return _error->Error(_("Error reading archive member header"));
+      Left -= sizeof(Head);
+
+      // Convert all of the integer members
+      Member *Memb = new Member();
+      if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
+	  StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
+	  StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
+	  StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
+	  StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
+      {
+	 delete Memb;
+	 return _error->Error(_("Invalid archive member header"));
+      }
+
+      if (Left < 0 || Memb->Size > static_cast<unsigned long long>(Left))
+      {
+	 delete Memb;
+	 return _error->Error(_("Invalid archive member header"));
+      }
+      // Check for an extra long name string
+      if (memcmp(Head.Name,"#1/",3) == 0)
+      {
+	 char S[300];
+	 unsigned long Len;
+	 if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
+	     Len >= sizeof(S))
+	 {
+	    delete Memb;
+	    return _error->Error(_("Invalid archive member header"));
+	 }
+
+	 if (Len > Memb->Size)
+	 {
+	    delete Memb;
+	    return _error->Error(_("Invalid archive member header"));
+	 }
+
+	 if (File.Read(S,Len) == false)
+	 {
+	    delete Memb;
+	    return false;
+	 }
+	 S[Len] = 0;
+	 Memb->Name = S;
+	 Memb->Size -= Len;
+	 Left -= Len;
+      }
+      else
+      {
+	 unsigned int I = sizeof(Head.Name) - 1;
+	 for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--)
+	 {
+	    if (I == 0)
+	    {
+	       delete Memb;
+	       return _error->Error(_("Invalid archive member header"));
+	    }
+	 }
+	 Memb->Name = std::string(Head.Name,I+1);
+      }
+
+      // Account for the AR header alignment 
+      off_t Skip = Memb->Size % 2;
+      
+      // Add it to the list
+      Memb->Next = List;
+      List = Memb;
+      Memb->Start = File.Tell();
+      if (File.Skip(Memb->Size + Skip) == false)
+	 return false;
+      if (Left < (off_t)(Memb->Size + Skip))
+	 return _error->Error(_("Archive is too short"));
+      Left -= Memb->Size + Skip;
+   }   
+   if (Left != 0)
+      return _error->Error(_("Failed to read the archive headers"));
+   
+   return true;
+}
+									/*}}}*/
+// ARArchive::FindMember - Find a name in the member list		/*{{{*/
+// ---------------------------------------------------------------------
+/* Find a member with the given name */
+const ARArchive::Member *ARArchive::FindMember(const char *Name) const
+{
+   const Member *Res = List;
+   while (Res != 0)
+   {
+      if (Res->Name == Name)
+	 return Res;
+      Res = Res->Next;
+   }
+   
+   return 0;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/arfile.h b/apt-pkg/contrib/arfile.h
new file mode 100644
index 0000000..9b13ed9
--- /dev/null
+++ b/apt-pkg/contrib/arfile.h
@@ -0,0 +1,66 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   AR File - Handle an 'AR' archive
+   
+   This is a reader for the usual 4.4 BSD AR format. It allows raw
+   stream access to a single member at a time. Basically all this class
+   provides is header parsing and verification. It is up to the client
+   to correctly make use of the stream start/stop points.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ARFILE_H
+#define PKGLIB_ARFILE_H
+
+#include <apt-pkg/macros.h>
+#include <string>
+
+class FileFd;
+
+class APT_PUBLIC ARArchive
+{
+   struct MemberHeader;
+   public:
+   struct Member;
+   
+   protected:
+
+   // Linked list of members
+   Member *List;
+   
+   bool LoadHeaders();
+
+   public:
+   
+   // The stream file
+   FileFd &File;
+
+   // Locate a member by name
+   const Member *FindMember(const char *Name) const;
+   inline Member *Members() { return List; }
+   
+   APT_PUBLIC explicit ARArchive(FileFd &File);
+   APT_PUBLIC ~ARArchive();
+};
+
+// A member of the archive
+struct ARArchive::Member
+{
+   // Fields from the header
+   std::string Name;
+   unsigned long MTime;
+   unsigned long UID;
+   unsigned long GID;
+   unsigned long Mode;
+   unsigned long long Size;
+   
+   // Location of the data.
+   unsigned long long Start;
+   Member *Next;
+   
+   Member() : Start(0), Next(0) {};
+};
+
+#endif
diff --git a/apt-pkg/contrib/cdromutl.cc b/apt-pkg/contrib/cdromutl.cc
new file mode 100644
index 0000000..f402017
--- /dev/null
+++ b/apt-pkg/contrib/cdromutl.cc
@@ -0,0 +1,293 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   CDROM Utilities - Some functions to manipulate CDROM mounts.
+   
+   These are here for the cdrom method and apt-cdrom.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cdromutl.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/strutl.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+// IsMounted - Returns true if the mount point is mounted		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a simple algorithm that should always work, we stat the mount point
+   and the '..' file in the mount point and see if they are on the same device.
+   By definition if they are the same then it is not mounted. This should 
+   account for symlinked mount points as well. */
+bool IsMounted(string &Path)
+{
+   if (Path.empty() == true)
+      return false;
+
+   // Need that trailing slash for directories
+   if (Path[Path.length() - 1] != '/')
+      Path += '/';
+
+   // if the path has a ".disk" directory we treat it as mounted
+   // this way even extracted copies of disks are recognized
+   if (DirectoryExists(Path + ".disk/") == true)
+      return true;
+
+   /* First we check if the path is actually mounted, we do this by
+      stating the path and the previous directory (careful of links!)
+      and comparing their device fields. */
+   struct stat Buf,Buf2;
+   if (stat(Path.c_str(),&Buf) != 0 || 
+       stat((Path + "../").c_str(),&Buf2) != 0)
+      return _error->Errno("stat",_("Unable to stat the mount point %s"),Path.c_str());
+
+   if (Buf.st_dev == Buf2.st_dev)
+      return false;
+   return true;
+}
+									/*}}}*/
+// UnmountCdrom - Unmount a cdrom					/*{{{*/
+// ---------------------------------------------------------------------
+/* Forking umount works much better than the umount syscall which can 
+   leave /etc/mtab inconsistent. We drop all messages this produces. */
+bool UnmountCdrom(string Path)
+{
+   // do not generate errors, even if the mountpoint does not exist
+   // the mountpoint might be auto-created by the mount command
+   // and a non-existing mountpoint is surely not mounted
+   _error->PushToStack();
+   bool const mounted = IsMounted(Path);
+   _error->RevertToStack();
+   if (mounted == false)
+      return true;
+
+   for (int i=0;i<3;i++)
+   {
+   
+      int Child = ExecFork();
+
+      // The child
+      if (Child == 0)
+      {
+	 // Make all the fds /dev/null
+	 int const null_fd = open("/dev/null",O_RDWR);
+	 for (int I = 0; I != 3; ++I)
+	    dup2(null_fd, I);
+
+	 if (_config->Exists("Acquire::cdrom::"+Path+"::UMount") == true)
+	 {
+	    if (system(_config->Find("Acquire::cdrom::"+Path+"::UMount").c_str()) != 0)
+	       _exit(100);
+	    _exit(0);	 	 
+	 }
+	 else
+	 {
+	    const char * const Args[] = {
+	       "umount",
+	       Path.c_str(),
+	       nullptr
+	    };
+	    execvp(Args[0], const_cast<char **>(Args));
+	    _exit(100);
+	 }
+      }
+
+      // if it can not be umounted, give it a bit more time
+      // this can happen when auto-mount magic or fs/cdrom prober attack
+      if (ExecWait(Child,"umount",true) == true)
+	 return true;
+      sleep(1);
+   }
+
+   return false;
+}
+									/*}}}*/
+// MountCdrom - Mount a cdrom						/*{{{*/
+// ---------------------------------------------------------------------
+/* We fork mount and drop all messages */
+bool MountCdrom(string Path, string DeviceName)
+{
+   // do not generate errors, even if the mountpoint does not exist
+   // the mountpoint might be auto-created by the mount command
+   _error->PushToStack();
+   bool const mounted = IsMounted(Path);
+   _error->RevertToStack();
+   if (mounted == true)
+      return true;
+
+   int Child = ExecFork();
+
+   // The child
+   if (Child == 0)
+   {
+      // Make all the fds /dev/null
+      int const null_fd = open("/dev/null",O_RDWR);
+      for (int I = 0; I != 3; ++I)
+	 dup2(null_fd, I);
+
+      if (_config->Exists("Acquire::cdrom::"+Path+"::Mount") == true)
+      {
+	 if (system(_config->Find("Acquire::cdrom::"+Path+"::Mount").c_str()) != 0)
+	    _exit(100);
+	 _exit(0);	 
+      }
+      else
+      {
+	 const char *Args[10];
+	 Args[0] = "mount";
+	 if (DeviceName == "") 
+	 {
+	    Args[1] = Path.c_str();
+	    Args[2] = 0;
+	 } else {
+	    Args[1] = DeviceName.c_str();
+	    Args[2] = Path.c_str();
+	    Args[3] = 0;
+	 }
+	 execvp(Args[0],(char **)Args);      
+	 _exit(100);
+      }      
+   }
+
+   // Wait for mount
+   return ExecWait(Child,"mount",true);
+}
+									/*}}}*/
+// IdentCdrom - Generate a unique string for this CD			/*{{{*/
+// ---------------------------------------------------------------------
+/* We convert everything we hash into a string, this prevents byte size/order
+   from effecting the outcome. */
+bool IdentCdrom(string CD,string &Res,unsigned int Version)
+{
+   Hashes Hash(Hashes::MD5SUM);
+   bool writable_media = false;
+
+   int dirfd = open(CD.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+   if (dirfd == -1)
+      return _error->Errno("open",_("Unable to read %s"),CD.c_str());
+
+   // if we are on a writable medium (like a usb-stick) that is just
+   // used like a cdrom don't use "." as it will constantly change,
+   // use .disk instead
+   if (faccessat(dirfd, ".", W_OK, 0) == 0)
+   {
+      int diskfd = openat(dirfd, "./.disk", O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0);
+      if (diskfd != -1)
+      {
+	 close(dirfd);
+	 dirfd = diskfd;
+	 writable_media = true;
+	 CD = CD.append("/.disk");
+	 if (_config->FindB("Debug::aptcdrom",false) == true)
+	    std::clog << "Found writable cdrom, using alternative path: " << CD
+	       << std::endl;
+      }
+   }
+
+   DIR * const D = fdopendir(dirfd);
+   if (D == nullptr)
+      return _error->Errno("opendir",_("Unable to read %s"),CD.c_str());
+
+   /* Run over the directory, we assume that the reader order will never
+      change as the media is read-only. In theory if the kernel did
+      some sort of wacked caching this might not be true.. */
+   for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+   {
+      // Skip some files..
+      if (strcmp(Dir->d_name,".") == 0 ||
+	  strcmp(Dir->d_name,"..") == 0)
+	 continue;
+
+      std::string S;
+      if (Version <= 1)
+	 S = std::to_string(Dir->d_ino);
+      else
+      {
+	 struct stat Buf;
+	 if (fstatat(dirfd, Dir->d_name, &Buf, 0) != 0)
+	    continue;
+	 S = std::to_string(Buf.st_mtime);
+      }
+
+      Hash.Add(S.c_str());
+      Hash.Add(Dir->d_name);
+   }
+
+   // Some stats from the fsys
+   std::string S;
+   if (_config->FindB("Debug::identcdrom",false) == false)
+   {
+      struct statvfs Buf;
+      if (fstatvfs(dirfd, &Buf) != 0)
+	 return _error->Errno("statfs",_("Failed to stat the cdrom"));
+
+      // We use a kilobyte block size to avoid overflow
+      S = std::to_string(Buf.f_blocks * (Buf.f_bsize / 1024));
+      if (writable_media == false)
+	 S.append(" ").append(std::to_string(Buf.f_bfree * (Buf.f_bsize / 1024)));
+      Hash.Add(S.c_str(), S.length());
+      strprintf(S, "-%u", Version);
+   }
+   else
+      strprintf(S, "-%u.debug", Version);
+
+   closedir(D);
+   Res = Hash.GetHashString(Hashes::MD5SUM).HashValue().append(std::move(S));
+   return true;
+}
+									/*}}}*/
+// FindMountPointForDevice - Find mountpoint for the given device	/*{{{*/
+string FindMountPointForDevice(const char *devnode)
+{
+   // this is the order that mount uses as well
+   std::vector<std::string> const mounts = _config->FindVector("Dir::state::MountPoints", "/etc/mtab,/proc/mount");
+
+   for (std::vector<std::string>::const_iterator m = mounts.begin(); m != mounts.end(); ++m)
+      if (FileExists(*m) == true)
+      {
+	 char * line = NULL;
+	 size_t line_len = 0;
+	 FILE * f = fopen(m->c_str(), "r");
+	 while(getline(&line, &line_len, f) != -1)
+	 {
+	    char * out[] = { NULL, NULL, NULL };
+	    TokSplitString(' ', line, out, 3);
+	    if (out[2] != NULL || out[1] == NULL || out[0] == NULL)
+	       continue;
+	    if (strcmp(out[0], devnode) != 0)
+	       continue;
+	    fclose(f);
+	    // unescape the \0XXX chars in the path
+	    string mount_point = out[1];
+	    free(line);
+	    return DeEscapeString(mount_point);
+	 }
+	 fclose(f);
+	 free(line);
+      }
+
+   return string();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/cdromutl.h b/apt-pkg/contrib/cdromutl.h
new file mode 100644
index 0000000..1384cea
--- /dev/null
+++ b/apt-pkg/contrib/cdromutl.h
@@ -0,0 +1,24 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   CDROM Utilities - Some functions to manipulate CDROM mounts.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CDROMUTL_H
+#define PKGLIB_CDROMUTL_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+
+
+// mount cdrom, DeviceName (e.g. /dev/sr0) is optional
+APT_PUBLIC bool MountCdrom(std::string Path, std::string DeviceName="");
+APT_PUBLIC bool UnmountCdrom(std::string Path);
+APT_PUBLIC bool IdentCdrom(std::string CD,std::string &Res,unsigned int Version = 2);
+APT_PUBLIC bool IsMounted(std::string &Path);
+APT_PUBLIC std::string FindMountPointForDevice(const char *device);
+
+#endif
diff --git a/apt-pkg/contrib/cmndline.cc b/apt-pkg/contrib/cmndline.cc
new file mode 100644
index 0000000..998af2f
--- /dev/null
+++ b/apt-pkg/contrib/cmndline.cc
@@ -0,0 +1,445 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Command Line Class - Sophisticated command line parser
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cmndline.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/strutl.h>
+
+#include <string>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+// CommandLine::CommandLine - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+CommandLine::CommandLine(Args *AList,Configuration *Conf) : ArgList(AList), 
+                                 Conf(Conf), FileList(0)
+{
+}
+CommandLine::CommandLine() : ArgList(NULL), Conf(NULL), FileList(0)
+{
+}
+									/*}}}*/
+// CommandLine::~CommandLine - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+CommandLine::~CommandLine()
+{
+   delete [] FileList;
+}
+									/*}}}*/
+// CommandLine::GetCommand - return the first non-option word		/*{{{*/
+char const * CommandLine::GetCommand(Dispatch const * const Map,
+      unsigned int const argc, char const * const * const argv)
+{
+   // if there is a -- on the line there must be the word we search for either
+   // before it (as -- marks the end of the options) or right after it (as we can't
+   // decide if the command is actually an option, given that in theory, you could
+   // have parameters named like commands)
+   for (size_t i = 1; i < argc; ++i)
+   {
+      if (strcmp(argv[i], "--") != 0)
+	 continue;
+      // check if command is before --
+      for (size_t k = 1; k < i; ++k)
+	 for (size_t j = 0; Map[j].Match != NULL; ++j)
+	    if (strcmp(argv[k], Map[j].Match) == 0)
+	       return Map[j].Match;
+      // see if the next token after -- is the command
+      ++i;
+      if (i < argc)
+	 for (size_t j = 0; Map[j].Match != NULL; ++j)
+	    if (strcmp(argv[i], Map[j].Match) == 0)
+	       return Map[j].Match;
+      // we found a --, but not a command
+      return NULL;
+   }
+   // no --, so search for the first word matching a command
+   // FIXME: How like is it that an option parameter will be also a valid Match ?
+   for (size_t i = 1; i < argc; ++i)
+   {
+      if (*(argv[i]) == '-')
+	 continue;
+      for (size_t j = 0; Map[j].Match != NULL; ++j)
+	 if (strcmp(argv[i], Map[j].Match) == 0)
+	    return Map[j].Match;
+   }
+   return NULL;
+}
+									/*}}}*/
+// CommandLine::Parse - Main action member				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool CommandLine::Parse(int argc,const char **argv)
+{
+   delete [] FileList;
+   FileList = new const char *[argc];
+   const char **Files = FileList;
+   int I;
+   for (I = 1; I != argc; I++)
+   {
+      const char *Opt = argv[I];
+      
+      // It is not an option
+      if (*Opt != '-')
+      {
+	 *Files++ = Opt;
+	 continue;
+      }
+      
+      Opt++;
+      
+      // Double dash signifies the end of option processing
+      if (*Opt == '-' && Opt[1] == 0)
+      {
+	 I++;
+	 break;
+      }
+      
+      // Single dash is a short option
+      if (*Opt != '-')
+      {
+	 // Iterate over each letter
+	 while (*Opt != 0)
+	 {	    
+	    // Search for the option
+	    Args *A;
+	    for (A = ArgList; A->end() == false && A->ShortOpt != *Opt; A++);
+	    if (A->end() == true)
+	       return _error->Error(_("Command line option '%c' [from %s] is not understood in combination with the other options."),*Opt,argv[I]);
+
+	    if (HandleOpt(I,argc,argv,Opt,A) == false)
+	       return false;
+	    if (*Opt != 0)
+	       Opt++;	       
+	 }
+	 continue;
+      }
+      
+      Opt++;
+
+      // Match up to a = against the list
+      Args *A;
+      const char *OptEnd = strchrnul(Opt, '=');
+      for (A = ArgList; A->end() == false &&
+	   (A->LongOpt == 0 || stringcasecmp(Opt,OptEnd,A->LongOpt) != 0);
+	   ++A);
+      
+      // Failed, look for a word after the first - (no-foo)
+      bool PreceedMatch = false;
+      if (A->end() == true)
+      {
+         Opt = (const char*) memchr(Opt, '-', OptEnd - Opt);
+	 if (Opt == NULL)
+	    return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+	 Opt++;
+	 
+	 for (A = ArgList; A->end() == false &&
+	      (A->LongOpt == 0 || stringcasecmp(Opt,OptEnd,A->LongOpt) != 0);
+	      ++A);
+
+	 // Failed again..
+	 if (A->end() == true && OptEnd - Opt != 1)
+	    return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+
+	 // The option could be a single letter option prefixed by a no-..
+	 if (A->end() == true)
+	 {
+	    for (A = ArgList; A->end() == false && A->ShortOpt != *Opt; A++);
+	    
+	    if (A->end() == true)
+	       return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+	 }
+	 
+	 // The option is not boolean
+	 if (A->IsBoolean() == false)
+	    return _error->Error(_("Command line option %s is not boolean"),argv[I]);
+	 PreceedMatch = true;
+      }
+      
+      // Deal with it.
+      OptEnd--;
+      if (HandleOpt(I,argc,argv,OptEnd,A,PreceedMatch) == false)
+	 return false;
+   }
+   
+   // Copy any remaining file names over
+   for (; I != argc; I++)
+      *Files++ = argv[I];
+   *Files = 0;
+
+   SaveInConfig(argc, argv);
+
+   return true;
+}
+									/*}}}*/
+// CommandLine::HandleOpt - Handle a single option including all flags	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a helper function for parser, it looks at a given argument
+   and looks for specific patterns in the string, it gets tokanized
+   -ruffly- like -*[yes|true|enable]-(o|longopt)[=][ ][argument] */
+bool CommandLine::HandleOpt(int &I,int argc,const char *argv[],
+			    const char *&Opt,Args *A,bool PreceedMatch)
+{
+   const char *Argument = 0;
+   bool CertainArg = false;
+   int IncI = 0;
+
+   /* Determine the possible location of an option or 0 if their is
+      no option */
+   if (Opt[1] == 0)
+   {
+      if (I + 1 < argc && argv[I+1][0] != '-')
+	 Argument = argv[I+1];
+
+      IncI = 1;
+   }
+   else
+   {
+      if (Opt[1] == '=')
+      {
+	 CertainArg = true;
+	 Argument = Opt + 2;
+      }      
+      else
+	 Argument = Opt + 1;
+   }
+   
+   // Option is an argument set
+   if ((A->Flags & HasArg) == HasArg)
+   {
+      if (Argument == 0)
+	 return _error->Error(_("Option %s requires an argument."),argv[I]);
+      Opt += strlen(Opt);
+      I += IncI;
+      
+      // Parse a configuration file
+      if ((A->Flags & ConfigFile) == ConfigFile)
+	 return ReadConfigFile(*Conf,Argument);
+
+      // Arbitrary item specification
+      if ((A->Flags & ArbItem) == ArbItem)
+      {
+	 const char * const J = strchr(Argument, '=');
+	 if (J == nullptr)
+	    return _error->Error(_("Option %s: Configuration item specification must have an =<val>."),argv[I]);
+
+	 Conf->Set(string(Argument,J-Argument), J+1);
+	 return true;
+      }
+      
+      const char *I = strchrnul(A->ConfName, ' ');
+      if (*I == ' ')
+	 Conf->Set(string(A->ConfName,0,I-A->ConfName),string(I+1) + Argument);
+      else
+	 Conf->Set(A->ConfName,string(I) + Argument);
+	 
+      return true;
+   }
+   
+   // Option is an integer level
+   if ((A->Flags & IntLevel) == IntLevel)
+   {
+      // There might be an argument
+      if (Argument != 0)
+      {
+	 char *EndPtr;
+	 unsigned long Value = strtol(Argument,&EndPtr,10);
+	 
+	 // Conversion failed and the argument was specified with an =s
+	 if (EndPtr == Argument && CertainArg == true)
+	    return _error->Error(_("Option %s requires an integer argument, not '%s'"),argv[I],Argument);
+
+	 // Conversion was ok, set the value and return
+	 if (EndPtr != 0 && EndPtr != Argument && *EndPtr == 0)
+	 {
+	    Conf->Set(A->ConfName,Value);
+	    Opt += strlen(Opt);
+	    I += IncI;
+	    return true;
+	 }	 
+      }      
+      
+      // Increase the level
+      Conf->Set(A->ConfName,Conf->FindI(A->ConfName)+1);
+      return true;
+   }
+  
+   // Option is a boolean
+   int Sense = -1;  // -1 is unspecified, 0 is yes 1 is no
+
+   // Look for an argument.
+   while (1)
+   {
+      // Look at preceding text
+      char Buffer[300];
+      if (Argument == 0)
+      {
+	 if (PreceedMatch == false)
+	    break;
+	 
+	 if (strlen(argv[I]) >= sizeof(Buffer))
+	    return _error->Error(_("Option '%s' is too long"),argv[I]);
+
+	 // Skip the leading dash
+	 const char *J = argv[I];
+	 for (; *J == '-'; J++)
+	    ;
+
+	 const char *JEnd = strchr(J, '-');
+	 if (JEnd != NULL)
+	 {
+	    strncpy(Buffer,J,JEnd - J);
+	    Buffer[JEnd - J] = 0;
+	    Argument = Buffer;
+	    CertainArg = true;
+	 }	 
+	 else
+	    break;
+      }
+
+      // Check for boolean
+      Sense = StringToBool(Argument);
+      if (Sense >= 0)
+      {
+	 // Eat the argument	 
+	 if (Argument != Buffer)
+	 {
+	    Opt += strlen(Opt);
+	    I += IncI;
+	 }	 
+	 break;
+      }
+
+      if (CertainArg == true)
+	 return _error->Error(_("Sense %s is not understood, try true or false."),Argument);
+      
+      Argument = 0;
+   }
+      
+   // Indeterminate sense depends on the flag
+   if (Sense == -1)
+   {
+      if ((A->Flags & InvBoolean) == InvBoolean)
+	 Sense = 0;
+      else
+	 Sense = 1;
+   }
+   
+   Conf->Set(A->ConfName,Sense);
+   return true;
+}
+									/*}}}*/
+// CommandLine::FileSize - Count the number of filenames		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned int CommandLine::FileSize() const
+{
+   unsigned int Count = 0;
+   for (const char **I = FileList; I != 0 && *I != 0; I++)
+      Count++;
+   return Count;
+}
+									/*}}}*/
+// CommandLine::DispatchArg - Do something with the first arg		/*{{{*/
+bool CommandLine::DispatchArg(Dispatch const * const Map,bool NoMatch)
+{
+   int I;
+   for (I = 0; Map[I].Match != 0; I++)
+   {
+      if (strcmp(FileList[0],Map[I].Match) == 0)
+      {
+	 bool Res = Map[I].Handler(*this);
+	 if (Res == false && _error->PendingError() == false)
+	    _error->Error("Handler silently failed");
+	 return Res;
+      }
+   }
+   
+   // No matching name
+   if (Map[I].Match == 0)
+   {
+      if (NoMatch == true)
+	 _error->Error(_("Invalid operation %s"),FileList[0]);
+   }
+   
+   return false;
+}
+									/*}}}*/
+// CommandLine::SaveInConfig - for output later in a logfile or so	/*{{{*/
+// ---------------------------------------------------------------------
+/* We save the commandline here to have it around later for e.g. logging.
+   It feels a bit like a hack here and isn't bulletproof, but it is better
+   than nothing after all. */
+void CommandLine::SaveInConfig(unsigned int const &argc, char const * const * const argv)
+{
+   char cmdline[100 + argc * 50];
+   memset(cmdline, 0, sizeof(cmdline));
+   unsigned int length = 0;
+   bool lastWasOption = false;
+   bool closeQuote = false;
+   for (unsigned int i = 0; i < argc && length < sizeof(cmdline); ++i, ++length)
+   {
+      for (unsigned int j = 0; argv[i][j] != '\0' && length < sizeof(cmdline)-2; ++j)
+      {
+	 // we can't really sensibly deal with quoting so skip it
+	 if (strchr("\"\'\r\n", argv[i][j]) != nullptr)
+	    continue;
+	 cmdline[length++] = argv[i][j];
+	 if (lastWasOption == true && argv[i][j] == '=')
+	 {
+	    // That is possibly an option: Quote it if it includes spaces,
+	    // the benefit is that this will eliminate also most false positives
+	    const char* c = strchr(&argv[i][j+1], ' ');
+	    if (c == NULL) continue;
+	    cmdline[length++] = '\'';
+	    closeQuote = true;
+	 }
+      }
+      if (closeQuote == true)
+      {
+	 cmdline[length++] = '\'';
+	 closeQuote = false;
+      }
+      // Problem: detects also --hello
+      if (cmdline[length-1] == 'o')
+	 lastWasOption = true;
+      cmdline[length] = ' ';
+   }
+   cmdline[--length] = '\0';
+   _config->Set("CommandLine::AsString", cmdline);
+}
+									/*}}}*/
+CommandLine::Args CommandLine::MakeArgs(char ShortOpt, char const *LongOpt, char const *ConfName, unsigned long Flags)/*{{{*/
+{
+   /* In theory, this should be a constructor for CommandLine::Args instead,
+      but this breaks compatibility as gcc thinks this is a c++11 initializer_list */
+   CommandLine::Args arg;
+   arg.ShortOpt = ShortOpt;
+   arg.LongOpt = LongOpt;
+   arg.ConfName = ConfName;
+   arg.Flags = Flags;
+   return arg;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/cmndline.h b/apt-pkg/contrib/cmndline.h
new file mode 100644
index 0000000..40d384f
--- /dev/null
+++ b/apt-pkg/contrib/cmndline.h
@@ -0,0 +1,113 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Command Line Class - Sophisticated command line parser
+   
+   This class provides a unified command line parser/option handliner/
+   configuration mechanism. It allows the caller to specify the option
+   set and map the option set into the configuration class or other
+   special functioning.
+   
+   Filenames are stripped from the option stream and put into their
+   own array.
+   
+   The argument descriptor array can be initialized as:
+   
+ CommandLine::Args Args[] = 
+ {{'q',"quiet","apt::get::quiet",CommandLine::IntLevel},
+  {0,0,0,0}};
+   
+   The flags mean,
+     HasArg - Means the argument has a value
+     IntLevel - Means the argument is an integer level indication, the
+                following -qqqq (+3) -q5 (=5) -q=5 (=5) are valid
+     Boolean  - Means it is true/false or yes/no. 
+                -d (true) --no-d (false) --yes-d (true)
+                --long (true) --no-long (false) --yes-long (true)
+                -d=yes (true) -d=no (false) Words like enable, disable,
+                true false, yes no and on off are recognized in logical 
+                places.
+     InvBoolean - Same as boolean but the case with no specified sense
+                  (first case) is set to false.
+     ConfigFile - Means this flag should be interprited as the name of 
+                  a config file to read in at this point in option processing.
+                  Implies HasArg.
+     ArbItem    - Means the item is an arbitrary configuration string of
+                  the form item=value, where item is passed directly
+                  to the configuration class.
+   The default, if the flags are 0 is to use Boolean
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CMNDLINE_H
+#define PKGLIB_CMNDLINE_H
+
+#include <apt-pkg/macros.h>
+
+
+class Configuration;
+
+class APT_PUBLIC CommandLine
+{
+   public:
+   struct Args;
+   struct Dispatch;
+   struct DispatchWithHelp;
+   
+   protected:
+   
+   Args *ArgList;
+   Configuration *Conf;
+   bool HandleOpt(int &I,int argc,const char *argv[],
+		  const char *&Opt,Args *A,bool PreceedeMatch = false);
+   void static SaveInConfig(unsigned int const &argc, char const * const * const argv);
+
+   public:
+   
+   enum AFlags 
+   {
+      HasArg = (1 << 0),
+      IntLevel = (1 << 1),
+      Boolean = (1 << 2),
+      InvBoolean = (1 << 3),
+      ConfigFile = (1 << 4) | HasArg,
+      ArbItem = (1 << 5) | HasArg
+   };
+
+   const char **FileList;
+   
+   bool Parse(int argc,const char **argv);
+   void ShowHelp();
+   unsigned int FileSize() const APT_PURE;
+   bool DispatchArg(Dispatch const * const List,bool NoMatch = true);
+      
+   static char const * GetCommand(Dispatch const * const Map,
+	 unsigned int const argc, char const * const * const argv) APT_PURE;
+
+   static CommandLine::Args MakeArgs(char ShortOpt, char const *LongOpt,
+	 char const *ConfName, unsigned long Flags) APT_PURE;
+
+   CommandLine();
+   CommandLine(Args *AList,Configuration *Conf);
+   ~CommandLine();
+};
+
+struct CommandLine::Args
+{
+   char ShortOpt;
+   const char *LongOpt;
+   const char *ConfName;
+   unsigned long Flags;
+   
+   inline bool end() {return ShortOpt == 0 && LongOpt == 0;};
+   inline bool IsBoolean() {return Flags == 0 || (Flags & (Boolean|InvBoolean)) != 0;};
+};
+
+struct CommandLine::Dispatch
+{
+   const char *Match;
+   bool (*Handler)(CommandLine &);
+};
+
+#endif
diff --git a/apt-pkg/contrib/configuration.cc b/apt-pkg/contrib/configuration.cc
new file mode 100644
index 0000000..1134ed6
--- /dev/null
+++ b/apt-pkg/contrib/configuration.cc
@@ -0,0 +1,1194 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Configuration Class
+   
+   This class provides a configuration file and command line parser
+   for a tree-oriented configuration environment. All runtime configuration
+   is stored in here.
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+
+   ##################################################################### */
+									/*}}}*/
+// Include files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/string_view.h>
+
+#include <ctype.h>
+#include <regex.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <algorithm>
+#include <array>
+#include <fstream>
+#include <iterator>
+#include <numeric>
+#include <sstream>
+#include <stack>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include <apti18n.h>
+
+using namespace std;
+									/*}}}*/
+
+Configuration *_config = new Configuration;
+
+/* TODO: This config verification shouldn't be using a static variable
+   but a Cnf-member – but that would need ABI breaks and stuff and for now
+   that really is an apt-dev-only tool, so it isn't that bad that it is
+   unusable and allaround a bit strange */
+enum class APT_HIDDEN ConfigType { UNDEFINED, INT, BOOL, STRING, STRING_OR_BOOL, STRING_OR_LIST, FILE, DIR, LIST, PROGRAM_PATH = FILE };
+APT_HIDDEN std::unordered_map<std::string, ConfigType> apt_known_config {};
+static std::string getConfigTypeString(ConfigType const type)		/*{{{*/
+{
+   switch (type)
+   {
+      case ConfigType::UNDEFINED: return "UNDEFINED";
+      case ConfigType::INT: return "INT";
+      case ConfigType::BOOL: return "BOOL";
+      case ConfigType::STRING: return "STRING";
+      case ConfigType::STRING_OR_BOOL: return "STRING_OR_BOOL";
+      case ConfigType::FILE: return "FILE";
+      case ConfigType::DIR: return "DIR";
+      case ConfigType::LIST: return "LIST";
+      case ConfigType::STRING_OR_LIST: return "STRING_OR_LIST";
+   }
+   return "UNKNOWN";
+}
+									/*}}}*/
+static ConfigType getConfigType(std::string const &type)		/*{{{*/
+{
+   if (type == "<INT>")
+      return ConfigType::INT;
+   else if (type == "<BOOL>")
+      return ConfigType::BOOL;
+   else if (type == "<STRING>")
+      return ConfigType::STRING;
+   else if (type == "<STRING_OR_BOOL>")
+      return ConfigType::STRING_OR_BOOL;
+   else if (type == "<FILE>")
+      return ConfigType::FILE;
+   else if (type == "<DIR>")
+      return ConfigType::DIR;
+   else if (type == "<LIST>")
+      return ConfigType::LIST;
+   else if (type == "<STRING_OR_LIST>")
+      return ConfigType::STRING_OR_LIST;
+   else if (type == "<PROGRAM_PATH>")
+      return ConfigType::PROGRAM_PATH;
+   return ConfigType::UNDEFINED;
+}
+									/*}}}*/
+// checkFindConfigOptionType - workhorse of option checking		/*{{{*/
+static void checkFindConfigOptionTypeInternal(std::string name, ConfigType const type)
+{
+   std::transform(name.begin(), name.end(), name.begin(), ::tolower);
+   auto known = apt_known_config.find(name);
+   if (known == apt_known_config.cend())
+   {
+      auto const rcolon = name.rfind(':');
+      if (rcolon != std::string::npos)
+      {
+	 known = apt_known_config.find(name.substr(0, rcolon) + ":*");
+	 if (known == apt_known_config.cend())
+	 {
+	    auto const parts = StringSplit(name, "::");
+	    size_t psize = parts.size();
+	    if (psize > 1)
+	    {
+	       for (size_t max = psize; max != 1; --max)
+	       {
+		  std::ostringstream os;
+		  std::copy(parts.begin(), parts.begin() + max, std::ostream_iterator<std::string>(os, "::"));
+		  os << "**";
+		  known = apt_known_config.find(os.str());
+		  if (known != apt_known_config.cend() && known->second == ConfigType::UNDEFINED)
+		     return;
+	       }
+	       for (size_t max = psize - 1; max != 1; --max)
+	       {
+		  std::ostringstream os;
+		  std::copy(parts.begin(), parts.begin() + max - 1, std::ostream_iterator<std::string>(os, "::"));
+		  os << "*::";
+		  std::copy(parts.begin() + max + 1, parts.end() - 1, std::ostream_iterator<std::string>(os, "::"));
+		  os << *(parts.end() - 1);
+		  known = apt_known_config.find(os.str());
+		  if (known != apt_known_config.cend())
+		     break;
+	       }
+	    }
+	 }
+      }
+   }
+   if (known == apt_known_config.cend())
+      _error->Warning("Using unknown config option »%s« of type %s",
+	    name.c_str(), getConfigTypeString(type).c_str());
+   else if (known->second != type)
+   {
+      if (known->second == ConfigType::DIR && type == ConfigType::FILE)
+	 ; // implementation detail
+      else if (type == ConfigType::STRING && (known->second == ConfigType::FILE || known->second == ConfigType::DIR))
+	 ; // TODO: that might be an error or not, we will figure this out later
+      else if (known->second == ConfigType::STRING_OR_BOOL && (type == ConfigType::BOOL || type == ConfigType::STRING))
+	 ;
+      else if (known->second == ConfigType::STRING_OR_LIST && (type == ConfigType::LIST || type == ConfigType::STRING))
+	 ;
+      else
+	 _error->Warning("Using config option »%s« of type %s as a type %s",
+	       name.c_str(), getConfigTypeString(known->second).c_str(), getConfigTypeString(type).c_str());
+   }
+}
+static void checkFindConfigOptionType(char const * const name, ConfigType const type)
+{
+   if (apt_known_config.empty())
+      return;
+   checkFindConfigOptionTypeInternal(name, type);
+}
+									/*}}}*/
+static bool LoadConfigurationIndex(std::string const &filename)		/*{{{*/
+{
+   apt_known_config.clear();
+   if (filename.empty())
+      return true;
+   Configuration Idx;
+   if (ReadConfigFile(Idx, filename) == false)
+      return false;
+
+   Configuration::Item const * Top = Idx.Tree(nullptr);
+   if (unlikely(Top == nullptr))
+      return false;
+
+   do {
+      if (Top->Value.empty() == false)
+      {
+	 std::string fulltag = Top->FullTag();
+	 std::transform(fulltag.begin(), fulltag.end(), fulltag.begin(), ::tolower);
+	 apt_known_config.emplace(std::move(fulltag), getConfigType(Top->Value));
+      }
+
+      if (Top->Child != nullptr)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != nullptr && Top->Next == nullptr)
+	 Top = Top->Parent;
+      if (Top != nullptr)
+	 Top = Top->Next;
+   } while (Top != nullptr);
+
+   return true;
+}
+									/*}}}*/
+
+// Configuration::Configuration - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+Configuration::Configuration() : ToFree(true)
+{
+   Root = new Item;
+}
+Configuration::Configuration(const Item *Root) : Root((Item *)Root), ToFree(false)
+{
+}
+									/*}}}*/
+// Configuration::~Configuration - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+Configuration::~Configuration()
+{
+   if (ToFree == false)
+      return;
+   
+   Item *Top = Root;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+            
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Item *Parent = Top->Parent;
+	 delete Top;
+	 Top = Parent;
+      }      
+      if (Top != 0)
+      {
+	 Item *Next = Top->Next;
+	 delete Top;
+	 Top = Next;
+      }
+   }
+}
+									/*}}}*/
+// Configuration::Lookup - Lookup a single item				/*{{{*/
+// ---------------------------------------------------------------------
+/* This will lookup a single item by name below another item. It is a 
+   helper function for the main lookup function */
+Configuration::Item *Configuration::Lookup(Item *Head,const char *S,
+					   unsigned long const &Len,bool const &Create)
+{
+   int Res = 1;
+   Item *I = Head->Child;
+   Item **Last = &Head->Child;
+   
+   // Empty strings match nothing. They are used for lists.
+   if (Len != 0)
+   {
+      for (; I != 0; Last = &I->Next, I = I->Next)
+	 if (Len == I->Tag.length() && (Res = stringcasecmp(I->Tag,S,S + Len)) == 0)
+	    break;
+   }
+   else
+      for (; I != 0; Last = &I->Next, I = I->Next);
+      
+   if (Res == 0)
+      return I;
+   if (Create == false)
+      return 0;
+   
+   I = new Item;
+   I->Tag.assign(S,Len);
+   I->Next = *Last;
+   I->Parent = Head;
+   *Last = I;
+   return I;
+}
+									/*}}}*/
+// Configuration::Lookup - Lookup a fully scoped item			/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs a fully scoped lookup of a given name, possibly creating
+   new items */
+Configuration::Item *Configuration::Lookup(const char *Name,bool const &Create)
+{
+   if (Name == 0)
+      return Root->Child;
+   
+   const char *Start = Name;
+   const char *End = Start + strlen(Name);
+   const char *TagEnd = Name;
+   Item *Itm = Root;
+   for (; End - TagEnd >= 2; TagEnd++)
+   {
+      if (TagEnd[0] == ':' && TagEnd[1] == ':')
+      {
+	 Itm = Lookup(Itm,Start,TagEnd - Start,Create);
+	 if (Itm == 0)
+	    return 0;
+	 TagEnd = Start = TagEnd + 2;	 
+      }
+   }   
+
+   // This must be a trailing ::, we create unique items in a list
+   if (End - Start == 0)
+   {
+      if (Create == false)
+	 return 0;
+   }
+   
+   Itm = Lookup(Itm,Start,End - Start,Create);
+   return Itm;
+}
+									/*}}}*/
+// Configuration::Find - Find a value					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string Configuration::Find(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::STRING);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+   {
+      if (Default == 0)
+	 return "";
+      else
+	 return Default;
+   }
+   
+   return Itm->Value;
+}
+									/*}}}*/
+// Configuration::FindFile - Find a Filename				/*{{{*/
+// ---------------------------------------------------------------------
+/* Directories are stored as the base dir in the Parent node and the
+   sub directory in sub nodes with the final node being the end filename
+ */
+string Configuration::FindFile(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::FILE);
+   const Item *RootItem = Lookup("RootDir");
+   std::string result =  (RootItem == 0) ? "" : RootItem->Value;
+   if(result.empty() == false && result[result.size() - 1] != '/')
+     result.push_back('/');
+
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+   {
+      if (Default != 0)
+	 result.append(Default);
+   }
+   else
+   {
+      string val = Itm->Value;
+      while (Itm->Parent != 0)
+      {
+	 if (Itm->Parent->Value.empty() == true)
+	 {
+	    Itm = Itm->Parent;
+	    continue;
+	 }
+
+	 // Absolute
+	 if (val.length() >= 1 && val[0] == '/')
+	 {
+	    if (val.compare(0, 9, "/dev/null") == 0)
+	       val.erase(9);
+	    break;
+	 }
+
+	 // ~/foo or ./foo
+	 if (val.length() >= 2 && (val[0] == '~' || val[0] == '.') && val[1] == '/')
+	    break;
+
+	 // ../foo
+	 if (val.length() >= 3 && val[0] == '.' && val[1] == '.' && val[2] == '/')
+	    break;
+
+	 if (Itm->Parent->Value.end()[-1] != '/')
+	    val.insert(0, "/");
+
+	 val.insert(0, Itm->Parent->Value);
+	 Itm = Itm->Parent;
+      }
+      result.append(val);
+   }
+   return flNormalize(result);
+}
+									/*}}}*/
+// Configuration::FindDir - Find a directory name			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is like findfile execept the result is terminated in a / */
+string Configuration::FindDir(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::DIR);
+   string Res = FindFile(Name,Default);
+   if (Res.end()[-1] != '/')
+   {
+      size_t const found = Res.rfind("/dev/null");
+      if (found != string::npos && found == Res.size() - 9)
+	 return Res; // /dev/null returning
+      return Res + '/';
+   }
+   return Res;
+}
+									/*}}}*/
+// Configuration::FindVector - Find a vector of values			/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns a vector of config values under the given item */
+vector<string> Configuration::FindVector(const char *Name, std::string const &Default, bool const Keys) const
+{
+   checkFindConfigOptionType(Name, ConfigType::LIST);
+   vector<string> Vec;
+   const Item *Top = Lookup(Name);
+   if (Top == NULL)
+      return VectorizeString(Default, ',');
+
+   if (Top->Value.empty() == false)
+      return VectorizeString(Top->Value, ',');
+
+   Item *I = Top->Child;
+   while(I != NULL)
+   {
+      Vec.push_back(Keys ? I->Tag : I->Value);
+      I = I->Next;
+   }
+   if (Vec.empty() == true)
+      return VectorizeString(Default, ',');
+
+   return Vec;
+}
+									/*}}}*/
+// Configuration::FindI - Find an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+int Configuration::FindI(const char *Name,int const &Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::INT);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+      return Default;
+   
+   char *End;
+   int Res = strtol(Itm->Value.c_str(),&End,0);
+   if (End == Itm->Value.c_str())
+      return Default;
+   
+   return Res;
+}
+									/*}}}*/
+// Configuration::FindB - Find a boolean type				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool Configuration::FindB(const char *Name,bool const &Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::BOOL);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+      return Default;
+   
+   return StringToBool(Itm->Value,Default);
+}
+									/*}}}*/
+// Configuration::FindAny - Find an arbitrary type			/*{{{*/
+// ---------------------------------------------------------------------
+/* a key suffix of /f, /d, /b or /i calls Find{File,Dir,B,I} */
+string Configuration::FindAny(const char *Name,const char *Default) const
+{
+   string key = Name;
+   char type = 0;
+
+   if (key.size() > 2 && key.end()[-2] == '/')
+   {
+      type = key.end()[-1];
+      key.resize(key.size() - 2);
+   }
+
+   switch (type)
+   {
+      // file
+      case 'f': 
+      return FindFile(key.c_str(), Default);
+      
+      // directory
+      case 'd': 
+      return FindDir(key.c_str(), Default);
+      
+      // bool
+      case 'b': 
+      return FindB(key, Default) ? "true" : "false";
+      
+      // int
+      case 'i': 
+      {
+	 char buf[16];
+	 snprintf(buf, sizeof(buf)-1, "%d", FindI(key, Default ? atoi(Default) : 0 ));
+	 return buf;
+      }
+   }
+
+   // fallback
+   return Find(Name, Default);
+}
+									/*}}}*/
+// Configuration::CndSet - Conditional Set a value			/*{{{*/
+// ---------------------------------------------------------------------
+/* This will not overwrite */
+void Configuration::CndSet(const char *Name,const string &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   if (Itm->Value.empty() == true)
+      Itm->Value = Value;
+}
+									/*}}}*/
+// Configuration::Set - Set an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::CndSet(const char *Name,int const Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0 || Itm->Value.empty() == false)
+      return;
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Itm->Value = S;
+}
+									/*}}}*/
+// Configuration::Set - Set a value					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Set(const char *Name,const string &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   Itm->Value = Value;
+}
+									/*}}}*/
+// Configuration::Set - Set an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Set(const char *Name,int const &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Itm->Value = S;
+}
+									/*}}}*/
+// Configuration::Clear - Clear an single value from a list	        /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name, int const &Value)
+{
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Clear(Name, S);
+}
+									/*}}}*/
+// Configuration::Clear - Clear an single value from a list	        /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name, string const &Value)
+{
+   Item *Top = Lookup(Name.c_str(),false);
+   if (Top == 0 || Top->Child == 0)
+      return;
+
+   Item *Tmp, *Prev, *I;
+   Prev = I = Top->Child;
+
+   while(I != NULL)
+   {
+      if(I->Value == Value)
+      {
+	 Tmp = I;
+	 // was first element, point parent to new first element
+	 if(Top->Child == Tmp)
+	    Top->Child = I->Next;
+	 I = I->Next;
+	 Prev->Next = I;
+	 delete Tmp;
+      } else {
+	 Prev = I;
+	 I = I->Next;
+      }
+   }
+     
+}
+									/*}}}*/
+// Configuration::Clear - Clear everything				/*{{{*/
+// ---------------------------------------------------------------------
+void Configuration::Clear()
+{
+   const Configuration::Item *Top = Tree(0);
+   while( Top != 0 )
+   {
+      Clear(Top->FullTag());
+      Top = Top->Next;
+   }
+}
+									/*}}}*/
+// Configuration::Clear - Clear an entire tree				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name)
+{
+   Item *Top = Lookup(Name.c_str(),false);
+   if (Top == 0) 
+      return;
+
+   Top->Value.clear();
+   Item *Stop = Top;
+   Top = Top->Child;
+   Stop->Child = 0;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Item *Tmp = Top;
+	 Top = Top->Parent;
+	 delete Tmp;
+	 
+	 if (Top == Stop)
+	    return;
+      }
+      
+      Item *Tmp = Top;
+      if (Top != 0)
+	 Top = Top->Next;
+      delete Tmp;
+   }
+}
+									/*}}}*/
+void Configuration::MoveSubTree(char const * const OldRootName, char const * const NewRootName)/*{{{*/
+{
+   // prevent NewRoot being a subtree of OldRoot
+   if (OldRootName == nullptr)
+      return;
+   if (NewRootName != nullptr)
+   {
+      if (strcmp(OldRootName, NewRootName) == 0)
+	 return;
+      std::string const oldroot = std::string(OldRootName) + "::";
+      if (strcasestr(NewRootName, oldroot.c_str()) != NULL)
+	 return;
+   }
+
+   Item * Top;
+   Item const * const OldRoot = Top = Lookup(OldRootName, false);
+   if (Top == nullptr)
+      return;
+   std::string NewRoot;
+   if (NewRootName != nullptr)
+      NewRoot.append(NewRootName).append("::");
+
+   Top->Value.clear();
+   Item * const Stop = Top;
+   Top = Top->Child;
+   Stop->Child = 0;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Set(NewRoot + Top->FullTag(OldRoot), Top->Value);
+	 Item const * const Tmp = Top;
+	 Top = Top->Parent;
+	 delete Tmp;
+
+	 if (Top == Stop)
+	    return;
+      }
+
+      Set(NewRoot + Top->FullTag(OldRoot), Top->Value);
+      Item const * const Tmp = Top;
+      if (Top != 0)
+	 Top = Top->Next;
+      delete Tmp;
+   }
+}
+									/*}}}*/
+// Configuration::Exists - Returns true if the Name exists		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool Configuration::Exists(const char *Name) const
+{
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0)
+      return false;
+   return true;
+}
+									/*}}}*/
+// Configuration::ExistsAny - Returns true if the Name, possibly	/*{{{*/
+// ---------------------------------------------------------------------
+/* qualified by /[fdbi] exists */
+bool Configuration::ExistsAny(const char *Name) const
+{
+   string key = Name;
+
+   if (key.size() > 2 && key.end()[-2] == '/')
+   {
+      if (key.find_first_of("fdbi",key.size()-1) < key.size())
+      {
+         key.resize(key.size() - 2);
+         if (Exists(key.c_str()))
+            return true;
+      }
+      else
+      {
+         _error->Warning(_("Unrecognized type abbreviation: '%c'"), key.end()[-3]);
+      }
+   }
+   return Exists(Name);
+}
+									/*}}}*/
+// Configuration::Dump - Dump the config				/*{{{*/
+// ---------------------------------------------------------------------
+/* Dump the entire configuration space */
+void Configuration::Dump(ostream& str)
+{
+   Dump(str, NULL, "%F \"%v\";\n", true);
+}
+void Configuration::Dump(ostream& str, char const * const root,
+			 char const * const formatstr, bool const emptyValue)
+{
+   const Configuration::Item* Top = Tree(root);
+   if (Top == 0)
+      return;
+   const Configuration::Item* const Root = (root == NULL) ? NULL : Top;
+   std::vector<std::string> const format = VectorizeString(formatstr, '%');
+
+   /* Write out all of the configuration directives by walking the
+      configuration tree */
+   do {
+      if (emptyValue == true || Top->Value.empty() == emptyValue)
+      {
+	 std::vector<std::string>::const_iterator f = format.begin();
+	 str << *f;
+	 for (++f; f != format.end(); ++f)
+	 {
+	    if (f->empty() == true)
+	    {
+	       ++f;
+	       str << '%' << *f;
+	       continue;
+	    }
+	    char const type = (*f)[0];
+	    if (type == 'f')
+	       str << Top->FullTag();
+	    else if (type == 't')
+	       str << Top->Tag;
+	    else if (type == 'v')
+	       str << Top->Value;
+	    else if (type == 'F')
+	       str << QuoteString(Top->FullTag(), "=\"\n");
+	    else if (type == 'T')
+	       str << QuoteString(Top->Tag, "=\"\n");
+	    else if (type == 'V')
+	       str << QuoteString(Top->Value, "=\"\n");
+	    else if (type == 'n')
+	       str << "\n";
+	    else if (type == 'N')
+	       str << "\t";
+	    else
+	       str << '%' << type;
+	    str << f->c_str() + 1;
+	 }
+      }
+
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+	 Top = Top->Parent;
+      if (Top != 0)
+	 Top = Top->Next;
+
+      if (Root != NULL)
+      {
+	 const Configuration::Item* I = Top;
+	 while(I != 0)
+	 {
+	    if (I == Root)
+	       break;
+	    else
+	       I = I->Parent;
+	 }
+	 if (I == 0)
+	    break;
+      }
+   } while (Top != 0);
+}
+									/*}}}*/
+
+// Configuration::Item::FullTag - Return the fully scoped tag		/*{{{*/
+// ---------------------------------------------------------------------
+/* Stop sets an optional max recursion depth if this item is being viewed as
+   part of a sub tree. */
+string Configuration::Item::FullTag(const Item *Stop) const
+{
+   if (Parent == 0 || Parent->Parent == 0 || Parent == Stop)
+      return Tag;
+   return Parent->FullTag(Stop) + "::" + Tag;
+}
+									/*}}}*/
+
+// ReadConfigFile - Read a configuration file				/*{{{*/
+// ---------------------------------------------------------------------
+/* The configuration format is very much like the named.conf format
+   used in bind8, in fact this routine can parse most named.conf files. 
+   Sectional config files are like bind's named.conf where there are 
+   sections like 'zone "foo.org" { .. };' This causes each section to be
+   added in with a tag like "zone::foo.org" instead of being split 
+   tag/value. AsSectional enables Sectional parsing.*/
+static void leaveCurrentScope(std::stack<std::string> &Stack, std::string &ParentTag)
+{
+   if (Stack.empty())
+      ParentTag.clear();
+   else
+   {
+      ParentTag = Stack.top();
+      Stack.pop();
+   }
+}
+bool ReadConfigFile(Configuration &Conf,const string &FName,bool const &AsSectional,
+		    unsigned const &Depth)
+{
+   // Open the stream for reading
+   FileFd F;
+   if (OpenConfigurationFileFd(FName, F) == false)
+      return false;
+
+   string LineBuffer;
+   std::stack<std::string> Stack;
+
+   // Parser state
+   string ParentTag;
+
+   int CurLine = 0;
+   bool InComment = false;
+   while (F.Eof() == false)
+   {
+      // The raw input line.
+      std::string Input;
+      if (F.ReadLine(Input) == false)
+	 Input.clear();
+      // The input line with comments stripped.
+      std::string Fragment;
+
+      // Expand tabs in the input line and remove leading and trailing whitespace.
+      Input = APT::String::Strip(SubstVar(Input, "\t", "        "));
+      CurLine++;
+
+      // Now strip comments; if the whole line is contained in a
+      // comment, skip this line.
+      APT::StringView Line{Input.data(), Input.size()};
+
+      // continued Multi line comment
+      if (InComment)
+      {
+	 size_t end = Line.find("*/");
+	 if (end != APT::StringView::npos)
+	 {
+	    Line.remove_prefix(end + 2);
+	    InComment = false;
+	 }
+	 else
+	    continue;
+      }
+
+      // Discard single line comments
+      {
+	 size_t start = 0;
+	 while ((start = Line.find("//", start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0)
+	    {
+	       ++start;
+	       continue;
+	    }
+	    Line.remove_suffix(Line.length() - start);
+	    break;
+	 }
+	 using APT::operator""_sv;
+	 constexpr std::array<APT::StringView, 3> magicComments { "clear"_sv, "include"_sv, "x-apt-configure-index"_sv };
+	 start = 0;
+	 while ((start = Line.find('#', start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0 ||
+		std::any_of(magicComments.begin(), magicComments.end(), [&](auto const m) { return Line.compare(start+1, m.length(), m) == 0; }))
+	    {
+	       ++start;
+	       continue;
+	    }
+	    Line.remove_suffix(Line.length() - start);
+	    break;
+	 }
+      }
+
+      // Look for multi line comments and build up the
+      // fragment.
+      Fragment.reserve(Line.length());
+      {
+	 size_t start = 0;
+	 while ((start = Line.find("/*", start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0)
+	    {
+	       start += 2;
+	       continue;
+	    }
+	    Fragment.append(Line.data(), start);
+	    auto const end = Line.find("*/", start + 2);
+	    if (end == APT::StringView::npos)
+	    {
+	       Line.clear();
+	       InComment = true;
+	       break;
+	    }
+	    else
+	       Line.remove_prefix(end + 2);
+	    start = 0;
+	 }
+	 if (not Line.empty())
+	    Fragment.append(Line.data(), Line.length());
+      }
+
+      // Skip blank lines.
+      if (Fragment.empty())
+	 continue;
+
+      // The line has actual content; interpret what it means.
+      bool InQuote = false;
+      auto Start = Fragment.cbegin();
+      auto End = Fragment.cend();
+      for (std::string::const_iterator I = Start;
+	   I != End; ++I)
+      {
+	 if (*I == '"')
+	    InQuote = !InQuote;
+
+	 if (InQuote == false && (*I == '{' || *I == ';' || *I == '}'))
+	 {
+	    // Put the last fragment into the buffer
+	    std::string::const_iterator NonWhitespaceStart = Start;
+	    std::string::const_iterator NonWhitespaceStop = I;
+	    for (; NonWhitespaceStart != I && isspace(*NonWhitespaceStart) != 0; ++NonWhitespaceStart)
+	      ;
+	    for (; NonWhitespaceStop != NonWhitespaceStart && isspace(NonWhitespaceStop[-1]) != 0; --NonWhitespaceStop)
+	      ;
+	    if (LineBuffer.empty() == false && NonWhitespaceStop - NonWhitespaceStart != 0)
+	       LineBuffer += ' ';
+	    LineBuffer += string(NonWhitespaceStart, NonWhitespaceStop);
+
+	    // Drop this from the input string, saving the character
+	    // that terminated the construct we just closed. (i.e., a
+	    // brace or a semicolon)
+	    char TermChar = *I;
+	    Start = I + 1;
+
+	    // Syntax Error
+	    if (TermChar == '{' && LineBuffer.empty() == true)
+	       return _error->Error(_("Syntax error %s:%u: Block starts with no name."),FName.c_str(),CurLine);
+
+	    // No string on this line
+	    if (LineBuffer.empty() == true)
+	    {
+	       if (TermChar == '}')
+		  leaveCurrentScope(Stack, ParentTag);
+	       continue;
+	    }
+
+	    // Parse off the tag
+	    string Tag;
+	    const char *Pos = LineBuffer.c_str();
+	    if (ParseQuoteWord(Pos,Tag) == false)
+	       return _error->Error(_("Syntax error %s:%u: Malformed tag"),FName.c_str(),CurLine);
+
+	    // Parse off the word
+	    string Word;
+	    bool NoWord = false;
+	    if (ParseCWord(Pos,Word) == false &&
+		ParseQuoteWord(Pos,Word) == false)
+	    {
+	       if (TermChar != '{')
+	       {
+		  Word = Tag;
+		  Tag = "";
+	       }
+	       else
+		  NoWord = true;
+	    }
+	    if (strlen(Pos) != 0)
+	       return _error->Error(_("Syntax error %s:%u: Extra junk after value"),FName.c_str(),CurLine);
+
+	    // Go down a level
+	    if (TermChar == '{')
+	    {
+	       Stack.push(ParentTag);
+
+	       /* Make sectional tags incorporate the section into the
+	          tag string */
+	       if (AsSectional == true && Word.empty() == false)
+	       {
+		  Tag.append("::").append(Word);
+		  Word.clear();
+	       }
+
+	       if (ParentTag.empty() == true)
+		  ParentTag = Tag;
+	       else
+		  ParentTag.append("::").append(Tag);
+	       Tag.clear();
+	    }
+
+	    // Generate the item name
+	    string Item;
+	    if (ParentTag.empty() == true)
+	       Item = Tag;
+	    else
+	    {
+	       if (TermChar != '{' || Tag.empty() == false)
+		  Item = ParentTag + "::" + Tag;
+	       else
+		  Item = ParentTag;
+	    }
+
+	    // Specials
+	    if (Tag.length() >= 1 && Tag[0] == '#')
+	    {
+	       if (ParentTag.empty() == false)
+		  return _error->Error(_("Syntax error %s:%u: Directives can only be done at the top level"),FName.c_str(),CurLine);
+	       Tag.erase(Tag.begin());
+	       if (Tag == "clear")
+		  Conf.Clear(Word);
+	       else if (Tag == "include")
+	       {
+		  if (Depth > 10)
+		     return _error->Error(_("Syntax error %s:%u: Too many nested includes"),FName.c_str(),CurLine);
+		  if (Word.length() > 2 && Word.end()[-1] == '/')
+		  {
+		     if (ReadConfigDir(Conf,Word,AsSectional,Depth+1) == false)
+			return _error->Error(_("Syntax error %s:%u: Included from here"),FName.c_str(),CurLine);
+		  }
+		  else
+		  {
+		     if (ReadConfigFile(Conf,Word,AsSectional,Depth+1) == false)
+			return _error->Error(_("Syntax error %s:%u: Included from here"),FName.c_str(),CurLine);
+		  }
+	       }
+	       else if (Tag == "x-apt-configure-index")
+	       {
+		  if (LoadConfigurationIndex(Word) == false)
+		     return _error->Warning("Loading the configure index %s in file %s:%u failed!", Word.c_str(), FName.c_str(), CurLine);
+	       }
+	       else
+		  return _error->Error(_("Syntax error %s:%u: Unsupported directive '%s'"),FName.c_str(),CurLine,Tag.c_str());
+	    }
+	    else if (Tag.empty() == true && NoWord == false && Word == "#clear")
+	       return _error->Error(_("Syntax error %s:%u: clear directive requires an option tree as argument"),FName.c_str(),CurLine);
+	    else
+	    {
+	       // Set the item in the configuration class
+	       if (NoWord == false)
+		  Conf.Set(Item,Word);
+	    }
+
+	    // Empty the buffer
+	    LineBuffer.clear();
+
+	    // Move up a tag, but only if there is no bit to parse
+	    if (TermChar == '}')
+	       leaveCurrentScope(Stack, ParentTag);
+	 }
+      }
+
+      // Store the remaining text, if any, in the current line buffer.
+
+      // NB: could change this to use string-based operations; I'm
+      // using strstrip now to ensure backwards compatibility.
+      //   -- dburrows 2008-04-01
+      {
+	char *Buffer = new char[End - Start + 1];
+	try
+	  {
+	    std::copy(Start, End, Buffer);
+	    Buffer[End - Start] = '\0';
+
+	    const char *Stripd = _strstrip(Buffer);
+	    if (*Stripd != 0 && LineBuffer.empty() == false)
+	      LineBuffer += " ";
+	    LineBuffer += Stripd;
+	  }
+	catch(...)
+	  {
+	    delete[] Buffer;
+	    throw;
+	  }
+	delete[] Buffer;
+      }
+   }
+
+   if (LineBuffer.empty() == false)
+      return _error->Error(_("Syntax error %s:%u: Extra junk at end of file"),FName.c_str(),CurLine);
+   return true;
+}
+									/*}}}*/
+// ReadConfigDir - Read a directory of config files			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool ReadConfigDir(Configuration &Conf,const string &Dir,
+		   bool const &AsSectional, unsigned const &Depth)
+{
+   _error->PushToStack();
+   auto const files = GetListOfFilesInDir(Dir, "conf", true, true);
+   auto const successfulList = not _error->PendingError();
+   _error->MergeWithStack();
+   return std::accumulate(files.cbegin(), files.cend(), true, [&](bool good, auto const &file) {
+      return ReadConfigFile(Conf, file, AsSectional, Depth) && good;
+   }) && successfulList;
+}
+									/*}}}*/
+// MatchAgainstConfig Constructor					/*{{{*/
+Configuration::MatchAgainstConfig::MatchAgainstConfig(char const * Config)
+{
+   std::vector<std::string> const strings = _config->FindVector(Config);
+   for (std::vector<std::string>::const_iterator s = strings.begin();
+	s != strings.end(); ++s)
+   {
+      regex_t *p = new regex_t;
+      if (regcomp(p, s->c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB) == 0)
+	 patterns.push_back(p);
+      else
+      {
+	 regfree(p);
+	 delete p;
+	 _error->Warning("Invalid regular expression '%s' in configuration "
+                         "option '%s' will be ignored.",
+                         s->c_str(), Config);
+	 continue;
+      }
+   }
+   if (strings.empty() == true)
+      patterns.push_back(NULL);
+}
+									/*}}}*/
+// MatchAgainstConfig Destructor					/*{{{*/
+Configuration::MatchAgainstConfig::~MatchAgainstConfig()
+{
+   clearPatterns();
+}
+void Configuration::MatchAgainstConfig::clearPatterns()
+{
+   for(std::vector<regex_t *>::const_iterator p = patterns.begin();
+	p != patterns.end(); ++p)
+   {
+      if (*p == NULL) continue;
+      regfree(*p);
+      delete *p;
+   }
+   patterns.clear();
+}
+									/*}}}*/
+// MatchAgainstConfig::Match - returns true if a pattern matches	/*{{{*/
+bool Configuration::MatchAgainstConfig::Match(char const * str) const
+{
+   for(std::vector<regex_t *>::const_iterator p = patterns.begin();
+	p != patterns.end(); ++p)
+      if (*p != NULL && regexec(*p, str, 0, 0, 0) == 0)
+	 return true;
+
+   return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/configuration.h b/apt-pkg/contrib/configuration.h
new file mode 100644
index 0000000..6ebf28d
--- /dev/null
+++ b/apt-pkg/contrib/configuration.h
@@ -0,0 +1,152 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Configuration Class
+   
+   This class provides a configuration file and command line parser
+   for a tree-oriented configuration environment. All runtime configuration
+   is stored in here.
+   
+   Each configuration name is given as a fully scoped string such as
+     Foo::Bar
+   And has associated with it a text string. The Configuration class only
+   provides storage and lookup for this tree, other classes provide
+   configuration file formats (and parsers/emitters if needed).
+
+   Most things can get by quite happily with,
+     cout << _config->Find("Foo::Bar") << endl;
+
+   A special extension, support for ordered lists is provided by using the
+   special syntax, "block::list::" the trailing :: designates the 
+   item as a list. To access the list you must use the tree function on
+   "block::list".
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CONFIGURATION_H
+#define PKGLIB_CONFIGURATION_H
+
+#include <regex.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <apt-pkg/macros.h>
+
+
+class APT_PUBLIC Configuration
+{
+   public:
+   
+   struct Item
+   {
+      std::string Value;
+      std::string Tag;
+      Item *Parent;
+      Item *Child;
+      Item *Next;
+      
+      std::string FullTag(const Item *Stop = 0) const;
+      
+      Item() : Parent(0), Child(0), Next(0) {};
+   };
+   
+   private:
+   
+   Item *Root;
+   bool ToFree;
+
+   Item *Lookup(Item *Head,const char *S,unsigned long const &Len,bool const &Create);
+   Item *Lookup(const char *Name,const bool &Create);
+   inline const Item *Lookup(const char *Name) const
+   {
+      return const_cast<Configuration *>(this)->Lookup(Name,false);
+   }  
+   
+   public:
+
+   std::string Find(const char *Name,const char *Default = 0) const;
+   std::string Find(std::string const &Name,const char *Default = 0) const {return Find(Name.c_str(),Default);};
+   std::string Find(std::string const &Name, std::string const &Default) const {return Find(Name.c_str(),Default.c_str());};
+   std::string FindFile(const char *Name,const char *Default = 0) const;
+   std::string FindDir(const char *Name,const char *Default = 0) const;
+   /** return a list of child options
+    *
+    * Options like Acquire::Languages are handled as lists which
+    * can be overridden and have a default. For the later two a comma
+    * separated list of values is supported.
+    *
+    * \param Name of the parent node
+    * \param Default list of values separated by commas */
+   std::vector<std::string> FindVector(const char *Name, std::string const &Default = "", bool const Keys = false) const;
+   std::vector<std::string> FindVector(std::string const &Name, std::string const &Default = "", bool const Keys = false) const { return FindVector(Name.c_str(), Default, Keys); };
+
+   int FindI(const char *Name,int const &Default = 0) const;
+   int FindI(std::string const &Name,int const &Default = 0) const {return FindI(Name.c_str(),Default);};
+   bool FindB(const char *Name,bool const &Default = false) const;
+   bool FindB(std::string const &Name,bool const &Default = false) const {return FindB(Name.c_str(),Default);};
+   std::string FindAny(const char *Name,const char *Default = 0) const;
+	      
+   inline void Set(const std::string &Name,const std::string &Value) {Set(Name.c_str(),Value);};
+   void CndSet(const char *Name,const std::string &Value);
+   void CndSet(const char *Name,const int Value);
+   void Set(const char *Name,const std::string &Value);
+   void Set(const char *Name,const int &Value);
+   
+   inline bool Exists(const std::string &Name) const {return Exists(Name.c_str());};
+   bool Exists(const char *Name) const;
+   bool ExistsAny(const char *Name) const;
+
+   void MoveSubTree(char const * const OldRoot, char const * const NewRoot);
+
+   // clear a whole tree
+   void Clear(const std::string &Name);
+   void Clear();
+
+   // remove a certain value from a list (e.g. the list of "APT::Keep-Fds")
+   void Clear(std::string const &List, std::string const &Value);
+   void Clear(std::string const &List, int const &Value);
+
+   inline const Item *Tree(const char *Name) const {return Lookup(Name);};
+
+   inline void Dump() { Dump(std::clog); };
+   void Dump(std::ostream& str);
+   void Dump(std::ostream& str, char const * const root,
+	     char const * const format, bool const emptyValue);
+
+   explicit Configuration(const Item *Root);
+   Configuration();
+   ~Configuration();
+
+   /** \brief match a string against a configurable list of patterns */
+   class MatchAgainstConfig
+   {
+     std::vector<regex_t *> patterns;
+     APT_HIDDEN void clearPatterns();
+
+   public:
+     explicit MatchAgainstConfig(char const * Config);
+     virtual ~MatchAgainstConfig();
+
+     /** \brief Returns \b true for a string matching one of the patterns */
+     bool Match(char const * str) const;
+     bool Match(std::string const &str) const { return Match(str.c_str()); };
+
+     /** \brief returns if the matcher setup was successful */
+     bool wasConstructedSuccessfully() const { return patterns.empty() == false; }
+   };
+};
+
+APT_PUBLIC extern Configuration *_config;
+
+APT_PUBLIC bool ReadConfigFile(Configuration &Conf,const std::string &FName,
+		    bool const &AsSectional = false,
+		    unsigned const &Depth = 0);
+
+APT_PUBLIC bool ReadConfigDir(Configuration &Conf,const std::string &Dir,
+		   bool const &AsSectional = false,
+		   unsigned const &Depth = 0);
+
+#endif
diff --git a/apt-pkg/contrib/error.cc b/apt-pkg/contrib/error.cc
new file mode 100644
index 0000000..dd28af1
--- /dev/null
+++ b/apt-pkg/contrib/error.cc
@@ -0,0 +1,336 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Global Error Class - Global error mechanism
+
+   We use a simple STL vector to store each error record. A PendingFlag
+   is kept which indicates when the vector contains a Sever error.
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+#include <list>
+#include <string>
+#include <errno.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+									/*}}}*/
+
+// Global Error Object							/*{{{*/
+GlobalError *_GetErrorObj()
+{
+   static thread_local GlobalError Obj;
+   return &Obj;
+}
+									/*}}}*/
+// GlobalError::GlobalError - Constructor				/*{{{*/
+GlobalError::GlobalError() : PendingFlag(false) {}
+									/*}}}*/
+// GlobalError::FatalE, Errno, WarningE, NoticeE and DebugE - Add to the list/*{{{*/
+#define GEMessage(NAME, TYPE) \
+bool GlobalError::NAME (const char *Function, const char *Description,...) { \
+	va_list args; \
+	size_t msgSize = 400; \
+	int const errsv = errno; \
+	bool retry; \
+	do { \
+		va_start(args,Description); \
+		retry = InsertErrno(TYPE, Function, Description, args, errsv, msgSize); \
+		va_end(args); \
+	} while (retry); \
+	return false; \
+}
+GEMessage(FatalE, FATAL)
+GEMessage(Errno, ERROR)
+GEMessage(WarningE, WARNING)
+GEMessage(NoticeE, NOTICE)
+GEMessage(DebugE, DEBUG)
+#undef GEMessage
+									/*}}}*/
+// GlobalError::InsertErrno - Get part of the errortype string from errno/*{{{*/
+bool GlobalError::InsertErrno(MsgType const &type, const char *Function,
+				const char *Description,...) {
+	va_list args;
+	size_t msgSize = 400;
+	int const errsv = errno;
+	bool retry;
+	do {
+		va_start(args,Description);
+		retry = InsertErrno(type, Function, Description, args, errsv, msgSize);
+		va_end(args);
+	} while (retry);
+	return false;
+}
+									/*}}}*/
+// GlobalError::InsertErrno - formats an error message with the errno	/*{{{*/
+bool GlobalError::InsertErrno(MsgType type, const char* Function,
+			      const char* Description, va_list &args,
+			      int const errsv, size_t &msgSize) {
+	char* S = (char*) malloc(msgSize);
+	int const n = snprintf(S, msgSize, "%s - %s (%i: %s)", Description,
+			       Function, errsv, strerror(errsv));
+	if (n > -1 && ((unsigned int) n) < msgSize);
+	else {
+		if (n > -1)
+			msgSize = n + 1;
+		else
+			msgSize *= 2;
+		free(S);
+		return true;
+	}
+
+	bool const geins = Insert(type, S, args, msgSize);
+	free(S);
+	return geins;
+}
+									/*}}}*/
+// GlobalError::Fatal, Error, Warning, Notice and Debug - Add to the list/*{{{*/
+#define GEMessage(NAME, TYPE) \
+bool GlobalError::NAME (const char *Description,...) { \
+	va_list args; \
+	size_t msgSize = 400; \
+	bool retry; \
+	do { \
+		va_start(args,Description); \
+		retry = Insert(TYPE, Description, args, msgSize); \
+		va_end(args); \
+	} while (retry); \
+	return false; \
+}
+GEMessage(Fatal, FATAL)
+GEMessage(Error, ERROR)
+GEMessage(Warning, WARNING)
+GEMessage(Notice, NOTICE)
+GEMessage(Debug, DEBUG)
+#undef GEMessage
+									/*}}}*/
+// GlobalError::Insert - Add a errotype message to the list		/*{{{*/
+bool GlobalError::Insert(MsgType const &type, const char *Description,...)
+{
+	va_list args;
+	size_t msgSize = 400;
+	bool retry;
+	do {
+		va_start(args,Description);
+		retry = Insert(type, Description, args, msgSize);
+		va_end(args);
+	} while (retry);
+	return false;
+}
+									/*}}}*/
+// GlobalError::Insert - Insert a new item at the end			/*{{{*/
+bool GlobalError::Insert(MsgType type, const char* Description,
+			 va_list &args, size_t &msgSize) {
+	char* S = (char*) malloc(msgSize);
+	int const n = vsnprintf(S, msgSize, Description, args);
+	if (n > -1 && ((unsigned int) n) < msgSize);
+	else {
+		if (n > -1)
+			msgSize = n + 1;
+		else
+			msgSize *= 2;
+ 		free(S);
+		return true;
+	}
+
+	Item const m(S, type);
+	Messages.push_back(m);
+
+	if (type == ERROR || type == FATAL)
+		PendingFlag = true;
+
+	if (type == FATAL || type == DEBUG)
+		std::clog << m << std::endl;
+
+	free(S);
+	return false;
+}
+									/*}}}*/
+// GlobalError::PopMessage - Pulls a single message out			/*{{{*/
+bool GlobalError::PopMessage(std::string &Text) {
+	if (Messages.empty() == true)
+		return false;
+
+	Item const msg = Messages.front();
+	Messages.pop_front();
+
+	bool const Ret = (msg.Type == ERROR || msg.Type == FATAL);
+	Text = msg.Text;
+	if (PendingFlag == false || Ret == false)
+		return Ret;
+
+	// check if another error message is pending
+	for (std::list<Item>::const_iterator m = Messages.begin();
+	     m != Messages.end(); ++m)
+		if (m->Type == ERROR || m->Type == FATAL)
+			return Ret;
+
+	PendingFlag = false;
+	return Ret;
+}
+									/*}}}*/
+// GlobalError::DumpErrors - Dump all of the errors/warns to cerr	/*{{{*/
+void GlobalError::DumpErrors(std::ostream &out, MsgType const &threshold,
+			     bool const &mergeStack) {
+	if (mergeStack == true)
+		for (std::list<MsgStack>::const_reverse_iterator s = Stacks.rbegin();
+		     s != Stacks.rend(); ++s)
+			std::copy(s->Messages.begin(), s->Messages.end(), std::front_inserter(Messages));
+
+	std::for_each(Messages.begin(), Messages.end(), [&threshold, &out](Item const &m) {
+		if (m.Type >= threshold)
+			out << m << std::endl;
+	});
+
+	Discard();
+}
+									/*}}}*/
+// GlobalError::Discard - Discard					/*{{{*/
+void GlobalError::Discard() {
+	Messages.clear();
+	PendingFlag = false;
+}
+									/*}}}*/
+// GlobalError::empty - does our error list include anything?		/*{{{*/
+bool GlobalError::empty(MsgType const &threshold) const {
+	if (PendingFlag == true)
+		return false;
+
+	if (Messages.empty() == true)
+		return true;
+
+	return std::find_if(Messages.begin(), Messages.end(), [&threshold](Item const &m) {
+		return m.Type >= threshold;
+	}) == Messages.end();
+}
+									/*}}}*/
+// GlobalError::PushToStack						/*{{{*/
+void GlobalError::PushToStack() {
+	Stacks.emplace_back(Messages, PendingFlag);
+	Discard();
+}
+									/*}}}*/
+// GlobalError::RevertToStack						/*{{{*/
+void GlobalError::RevertToStack() {
+	Discard();
+	MsgStack pack = Stacks.back();
+	Messages = pack.Messages;
+	PendingFlag = pack.PendingFlag;
+	Stacks.pop_back();
+}
+									/*}}}*/
+// GlobalError::MergeWithStack						/*{{{*/
+void GlobalError::MergeWithStack() {
+	MsgStack pack = Stacks.back();
+	Messages.splice(Messages.begin(), pack.Messages);
+	PendingFlag = PendingFlag || pack.PendingFlag;
+	Stacks.pop_back();
+}
+									/*}}}*/
+
+// GlobalError::Item::operator<<						/*{{{*/
+APT_HIDDEN std::ostream &operator<<(std::ostream &out, GlobalError::Item i)
+{
+   static constexpr auto COLOR_RESET = "\033[0m";
+   static constexpr auto COLOR_NOTICE = "\033[33m";  // normal yellow
+   static constexpr auto COLOR_WARN = "\033[1;33m";  // bold yellow
+   static constexpr auto COLOR_ERROR = "\033[1;31m"; // bold red
+
+   bool use_color = _config->FindB("APT::Color", false);
+
+   if (use_color)
+   {
+      switch (i.Type)
+      {
+      case GlobalError::FATAL:
+      case GlobalError::ERROR:
+	 out << COLOR_ERROR;
+	 break;
+      case GlobalError::WARNING:
+	 out << COLOR_WARN;
+	 break;
+      case GlobalError::NOTICE:
+	 out << COLOR_NOTICE;
+	 break;
+      default:
+	 break;
+      }
+   }
+
+   switch (i.Type)
+   {
+   case GlobalError::FATAL:
+   case GlobalError::ERROR:
+      out << 'E';
+      break;
+   case GlobalError::WARNING:
+      out << 'W';
+      break;
+   case GlobalError::NOTICE:
+      out << 'N';
+      break;
+   case GlobalError::DEBUG:
+      out << 'D';
+      break;
+   }
+   out << ": ";
+
+   if (use_color)
+   {
+      switch (i.Type)
+      {
+      case GlobalError::FATAL:
+      case GlobalError::ERROR:
+      case GlobalError::WARNING:
+      case GlobalError::NOTICE:
+	 out << COLOR_RESET;
+	 break;
+      default:
+	 break;
+      }
+   }
+
+   std::string::size_type line_start = 0;
+   std::string::size_type line_end;
+   while ((line_end = i.Text.find_first_of("\n\r", line_start)) != std::string::npos)
+   {
+      if (line_start != 0)
+	 out << std::endl
+	     << "   ";
+      out << i.Text.substr(line_start, line_end - line_start);
+      line_start = i.Text.find_first_not_of("\n\r", line_end + 1);
+      if (line_start == std::string::npos)
+	 break;
+   }
+   if (line_start == 0)
+      out << i.Text;
+   else if (line_start != std::string::npos)
+      out << std::endl
+	  << "   " << i.Text.substr(line_start);
+
+   if (use_color)
+      out << COLOR_RESET;
+
+   return out;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/error.h b/apt-pkg/contrib/error.h
new file mode 100644
index 0000000..dd50b9c
--- /dev/null
+++ b/apt-pkg/contrib/error.h
@@ -0,0 +1,349 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Global Error Class - Global error mechanism
+
+   This class has a single global instance. When a function needs to 
+   generate an error condition, such as a read error, it calls a member
+   in this class to add the error to a stack of errors. 
+   
+   By using a stack the problem with a scheme like errno is removed and
+   it allows a very detailed account of what went wrong to be transmitted
+   to the UI for display. (Errno has problems because each function sets
+   errno to 0 if it didn't have an error thus eraseing erno in the process
+   of cleanup)
+   
+   Several predefined error generators are provided to handle common 
+   things like errno. The general idea is that all methods return a bool.
+   If the bool is true then things are OK, if it is false then things 
+   should start being undone and the stack should unwind under program
+   control.
+   
+   A Warning should not force the return of false. Things did not fail, but
+   they might have had unexpected problems. Errors are stored in a FIFO
+   so Pop will return the first item..
+   
+   I have some thoughts about extending this into a more general UI<-> 
+   Engine interface, ie allowing the Engine to say 'The disk is full' in 
+   a dialog that says 'Panic' and 'Retry'.. The error generator functions
+   like errno, Warning and Error return false always so this is normal:
+     if (open(..))
+        return _error->Errno(..);
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ERROR_H
+#define PKGLIB_ERROR_H
+
+#include <apt-pkg/macros.h>
+
+#include <iostream>
+#include <list>
+#include <string>
+
+#include <stdarg.h>
+#include <stddef.h>
+
+class APT_PUBLIC GlobalError						/*{{{*/
+{
+public:									/*{{{*/
+	/** \brief a message can have one of following severity */
+	enum MsgType {
+		/** \brief Message will be printed instantly as it is likely that
+			this error will lead to a complete crash */
+		FATAL = 40,
+		/** \brief An error does hinder the correct execution and should be corrected */
+		ERROR = 30,
+		/** \brief indicates problem that can lead to errors later on */
+		WARNING = 20,
+		/** \brief deprecation warnings, old fallback behavior, … */
+		NOTICE = 10,
+		/** \brief for developers only in areas it is hard to print something directly */
+		DEBUG = 0
+	};
+
+	/** \brief add a fatal error message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool FatalE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add an Error message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool Errno(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a warning message with errno to the list
+	 *
+	 *  A warning should be considered less severe than an error and
+	 *  may be ignored by the client.
+	 *
+	 *  \param Function Name of the function generates the warning.
+	 *  \param Description Format string for the warning message.
+	 *
+	 *  \return \b false
+	 */
+	bool WarningE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a notice message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool NoticeE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a debug message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool DebugE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief adds an errno message with the given type
+	 *
+	 * \param type of the error message
+	 * \param Function which failed
+	 * \param Description of the error
+	 */
+	bool InsertErrno(MsgType const &type, const char* Function,
+			 const char* Description,...) APT_PRINTF(4) APT_COLD;
+
+	/** \brief adds an errno message with the given type
+	 *
+	 * args needs to be initialized with va_start and terminated
+	 * with va_end by the caller. msgSize is also an out-parameter
+	 * in case the msgSize was not enough to store the complete message.
+	 *
+	 * \param type of the error message
+	 * \param Function which failed
+	 * \param Description is the format string for args
+	 * \param args list from a printf-like function
+	 * \param errsv is the errno the error is for
+	 * \param msgSize is the size of the char[] used to store message
+	 * \return true if the message was added, false if not - the caller
+	 * should call this method again in that case
+	 */
+	bool InsertErrno(MsgType type, const char* Function,
+			 const char* Description, va_list &args,
+			 int const errsv, size_t &msgSize) APT_COLD;
+
+	/** \brief add an fatal error message to the list
+	 *
+	 *  Most of the stuff we consider as "error" is also "fatal" for
+	 *  the user as the application will not have the expected result,
+	 *  but a fatal message here means that it gets printed directly
+	 *  to stderr in addition to adding it to the list as the error
+	 *  leads sometimes to crashes and a maybe duplicated message
+	 *  is better than "Segfault" as the only displayed text
+	 *
+	 *  \param Description Format string for the fatal error message.
+	 *
+	 *  \return \b false
+	 */
+	bool Fatal(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add an Error message to the list
+	 *
+	 *  \param Description Format string for the error message.
+	 *
+	 *  \return \b false
+	 */
+	bool Error(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a warning message to the list
+	 *
+	 *  A warning should be considered less severe than an error and
+	 *  may be ignored by the client.
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Warning(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a notice message to the list
+	 *
+	 *  A notice should be considered less severe than an error or a
+	 *  warning and can be ignored by the client without further problems
+	 *  for some times, but he should consider fixing the problem.
+	 *  This error type can be used for e.g. deprecation warnings of options.
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Notice(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a debug message to the list
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Debug(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief adds an error message with the given type
+	 *
+	 * \param type of the error message
+	 * \param Description of the error
+	 */
+	bool Insert(MsgType const &type, const char* Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief adds an error message with the given type
+	 *
+	 * args needs to be initialized with va_start and terminated
+	 * with va_end by the caller. msgSize is also an out-parameter
+	 * in case the msgSize was not enough to store the complete message.
+	 *
+	 * \param type of the error message
+	 * \param Description is the format string for args
+	 * \param args list from a printf-like function
+	 * \param msgSize is the size of the char[] used to store message
+	 * \return true if the message was added, false if not - the caller
+	 * should call this method again in that case
+	 */
+	bool Insert(MsgType type, const char* Description,
+			 va_list &args, size_t &msgSize) APT_COLD;
+
+	/** \brief is an error in the list?
+	 *
+	 *  \return \b true if an error is included in the list, \b false otherwise
+	 */
+	inline bool PendingError() const APT_PURE {return PendingFlag;};
+
+	/** \brief is the list empty?
+	 *
+	 *  Can be used to check if the current stack level doesn't include
+	 *  anything equal or more severe than a given threshold, defaulting
+	 *  to warning level for historic reasons.
+	 *
+	 *  \param threshold minimum level considered
+	 *
+	 *  \return \b true if the list is empty, \b false otherwise
+	 */
+	bool empty(MsgType const &threshold = WARNING) const APT_PURE;
+
+	/** \brief returns and removes the first (or last) message in the list
+	 *
+	 *  \param[out] Text message of the first/last item
+	 *
+	 *  \return \b true if the message was an error, \b false otherwise
+	 */
+	bool PopMessage(std::string &Text);
+
+	/** \brief clears the list of messages */
+	void Discard();
+
+	/** \brief outputs the list of messages to the given stream
+	 *
+	 *  Note that all messages are discarded, even undisplayed ones.
+	 *
+	 *  \param[out] out output stream to write the messages in
+	 *  \param threshold minimum level considered
+	 *  \param mergeStack if true recursively dumps the entire stack
+	 */
+	void DumpErrors(std::ostream &out, MsgType const &threshold = WARNING,
+			bool const &mergeStack = true);
+
+	/** \brief dumps the list of messages to std::cerr
+	 *
+	 *  Note that all messages are discarded, also the notices
+	 *  displayed or not.
+	 *
+	 *  \param threshold minimum level printed
+	 */
+	void inline DumpErrors(MsgType const &threshold) {
+		DumpErrors(std::cerr, threshold);
+	}
+
+        // mvo: we do this instead of using a default parameter in the
+        //      previous declaration to avoid a (subtle) API break for
+        //      e.g. sigc++ and mem_fun0
+	/** \brief dumps the messages of type WARNING or higher to std::cerr
+	 *
+	 *  Note that all messages are discarded, displayed or not.
+	 *
+	 */
+	void inline DumpErrors() {
+                DumpErrors(WARNING);
+	}
+
+	/** \brief put the current Messages into the stack
+	 *
+	 *  All "old" messages will be pushed into a stack to
+	 *  them later back, but for now the Message query will be
+	 *  empty and performs as no messages were present before.
+	 *
+	 * The stack can be as deep as you want - all stack operations
+	 * will only operate on the last element in the stack.
+	 */
+	void PushToStack();
+
+	/** \brief throw away all current messages */
+	void RevertToStack();
+
+	/** \brief merge current and stack together */
+	void MergeWithStack();
+
+	/** \brief return the deep of the stack */
+	size_t StackCount() const APT_PURE {
+		return Stacks.size();
+	}
+
+	GlobalError();
+									/*}}}*/
+private:								/*{{{*/
+	struct Item {
+		std::string Text;
+		MsgType Type;
+
+		Item(char const *Text, MsgType const &Type) :
+			Text(Text), Type(Type) {};
+
+		APT_HIDDEN friend std::ostream &operator<<(std::ostream &out, Item i);
+	};
+
+	APT_HIDDEN friend std::ostream &operator<<(std::ostream &out, Item i);
+
+	std::list<Item> Messages;
+	bool PendingFlag;
+
+	struct MsgStack {
+		std::list<Item> Messages;
+		bool const PendingFlag;
+
+		MsgStack(std::list<Item> const &Messages, bool const &Pending) :
+			 Messages(Messages), PendingFlag(Pending) {};
+	};
+
+	std::list<MsgStack> Stacks;
+									/*}}}*/
+};
+									/*}}}*/
+
+// The 'extra-ansi' syntax is used to help with collisions. 
+APT_PUBLIC GlobalError *_GetErrorObj();
+static struct {
+	inline GlobalError* operator ->() { return _GetErrorObj(); }
+} _error APT_UNUSED;
+
+#endif
diff --git a/apt-pkg/contrib/extracttar.cc b/apt-pkg/contrib/extracttar.cc
new file mode 100644
index 0000000..dc24375
--- /dev/null
+++ b/apt-pkg/contrib/extracttar.cc
@@ -0,0 +1,325 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Extract a Tar - Tar Extractor
+
+   Some performance measurements showed that zlib performed quite poorly
+   in comparison to a forked gzip process. This tar extractor makes use
+   of the fact that dup'd file descriptors have the same seek pointer
+   and that gzip will not read past the end of a compressed stream, 
+   even if there is more data. We use the dup property to track extraction
+   progress and the gzip feature to just feed gzip a fd in the middle
+   of an AR file. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/extracttar.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <fcntl.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+    
+// The on disk header for a tar file.
+struct ExtractTar::TarHeader
+{
+   char Name[100];
+   char Mode[8];
+   char UserID[8];
+   char GroupID[8];
+   char Size[12];
+   char MTime[12];
+   char Checksum[8];
+   char LinkFlag;
+   char LinkName[100];
+   char MagicNumber[8];
+   char UserName[32];
+   char GroupName[32];
+   char Major[8];
+   char Minor[8];      
+};
+
+// We need to read long names (names and link targets) into memory, so let's
+// have a limit (shamelessly stolen from libarchive) to avoid people OOMing
+// us with large streams.
+static const unsigned long long APT_LONGNAME_LIMIT = 1048576llu;
+
+// A file size limit that we allow extracting. Currently, that's 128 GB.
+// We also should leave some wiggle room for code adding files to it, and
+// possibly conversion for signed, so this should not be larger than like 2**62.
+static const unsigned long long APT_FILESIZE_LIMIT = 1llu << 37;
+
+// ExtractTar::ExtractTar - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::ExtractTar(FileFd &Fd,unsigned long long Max,string DecompressionProgram)
+	: File(Fd), MaxInSize(Max), DecompressProg(DecompressionProgram)
+{
+   GZPid = -1;
+   Eof = false;
+}
+									/*}}}*/
+// ExtractTar::ExtractTar - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::~ExtractTar()
+{
+   // Error close
+   Done();
+}
+									/*}}}*/
+// ExtractTar::Done - Reap the gzip sub process				/*{{{*/
+bool ExtractTar::Done()
+{
+   return InFd.Close();
+}
+									/*}}}*/
+// ExtractTar::StartGzip - Startup gzip					/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a gzip sub process that has its input as the file itself.
+   If this tar file is embedded into something like an ar file then 
+   gzip will efficiently ignore the extra bits. */
+bool ExtractTar::StartGzip()
+{
+   if (DecompressProg.empty())
+   {
+      InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, FileFd::None, false);
+      return true;
+   }
+
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   for (; compressor != compressors.end(); ++compressor) {
+      if (compressor->Name == DecompressProg) {
+	 return InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, *compressor, false);
+      }
+   }
+
+   return _error->Error(_("Cannot find a configured compressor for '%s'"),
+			DecompressProg.c_str());
+
+}
+									/*}}}*/
+// ExtractTar::Go - Perform extraction					/*{{{*/
+// ---------------------------------------------------------------------
+/* This reads each 512 byte block from the archive and extracts the header
+   information into the Item structure. Then it resolves the UID/GID and
+   invokes the correct processing function. */
+bool ExtractTar::Go(pkgDirStream &Stream)
+{   
+   if (StartGzip() == false)
+      return false;
+   
+   // Loop over all blocks
+   string LastLongLink, ItemLink;
+   string LastLongName, ItemName;
+   while (1)
+   {
+      bool BadRecord = false;      
+      unsigned char Block[512];      
+      if (InFd.Read(Block,sizeof(Block),true) == false)
+	 return false;
+      
+      if (InFd.Eof() == true)
+	 break;
+
+      // Get the checksum
+      TarHeader *Tar = (TarHeader *)Block;
+      unsigned long CheckSum;
+      if (StrToNum(Tar->Checksum,CheckSum,sizeof(Tar->Checksum),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+      
+      /* Compute the checksum field. The actual checksum is blanked out
+         with spaces so it is not included in the computation */
+      unsigned long NewSum = 0;
+      memset(Tar->Checksum,' ',sizeof(Tar->Checksum));
+      for (int I = 0; I != sizeof(Block); I++)
+	 NewSum += Block[I];
+      
+      /* Check for a block of nulls - in this case we kill gzip, GNU tar
+       	 does this.. */
+      if (NewSum == ' '*sizeof(Tar->Checksum))
+	 return Done();
+      
+      if (NewSum != CheckSum)
+	 return _error->Error(_("Tar checksum failed, archive corrupted"));
+   
+      // Decode all of the fields
+      pkgDirStream::Item Itm;
+      if (StrToNum(Tar->Mode,Itm.Mode,sizeof(Tar->Mode),8) == false ||
+          (Base256ToNum(Tar->UserID,Itm.UID,8) == false &&
+	     StrToNum(Tar->UserID,Itm.UID,sizeof(Tar->UserID),8) == false) ||
+          (Base256ToNum(Tar->GroupID,Itm.GID,8) == false &&
+	     StrToNum(Tar->GroupID,Itm.GID,sizeof(Tar->GroupID),8) == false) ||
+          (Base256ToNum(Tar->Size,Itm.Size,12) == false &&
+	     StrToNum(Tar->Size,Itm.Size,sizeof(Tar->Size),8) == false) ||
+          (Base256ToNum(Tar->MTime,Itm.MTime,12) == false &&
+	     StrToNum(Tar->MTime,Itm.MTime,sizeof(Tar->MTime),8) == false) ||
+	  StrToNum(Tar->Major,Itm.Major,sizeof(Tar->Major),8) == false ||
+	  StrToNum(Tar->Minor,Itm.Minor,sizeof(Tar->Minor),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+
+      // Security check. Prevents overflows below the code when rounding up in skip/copy code,
+      // and provides modest protection against decompression bombs.
+      if (Itm.Size > APT_FILESIZE_LIMIT)
+	 return _error->Error("Tar member too large: %llu > %llu bytes", Itm.Size, APT_FILESIZE_LIMIT);
+
+      // Grab the filename and link target: use last long name if one was
+      // set, otherwise use the header value as-is, but remember that it may
+      // fill the entire 100-byte block and needs to be zero-terminated.
+      // See Debian Bug #689582.
+      if (LastLongName.empty() == false)
+	 Itm.Name = (char *)LastLongName.c_str();
+      else
+	 Itm.Name = (char *)ItemName.assign(Tar->Name, sizeof(Tar->Name)).c_str();
+      if (Itm.Name[0] == '.' && Itm.Name[1] == '/' && Itm.Name[2] != 0)
+	 Itm.Name += 2;
+
+      if (LastLongLink.empty() == false)
+	 Itm.LinkTarget = (char *)LastLongLink.c_str();
+      else
+	 Itm.LinkTarget = (char *)ItemLink.assign(Tar->LinkName, sizeof(Tar->LinkName)).c_str();
+
+      // Convert the type over
+      switch (Tar->LinkFlag)
+      {
+	 case NormalFile0:
+	 case NormalFile:
+	 Itm.Type = pkgDirStream::Item::File;
+	 break;
+	 
+	 case HardLink:
+	 Itm.Type = pkgDirStream::Item::HardLink;
+	 break;
+	 
+	 case SymbolicLink:
+	 Itm.Type = pkgDirStream::Item::SymbolicLink;
+	 break;
+	 
+	 case CharacterDevice:
+	 Itm.Type = pkgDirStream::Item::CharDevice;
+	 break;
+	    
+	 case BlockDevice:
+	 Itm.Type = pkgDirStream::Item::BlockDevice;
+	 break;
+	 
+	 case Directory:
+	 Itm.Type = pkgDirStream::Item::Directory;
+	 break;
+	 
+	 case FIFO:
+	 Itm.Type = pkgDirStream::Item::FIFO;
+	 break;
+
+	 case GNU_LongLink:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length <= sizeof(Block))
+	       {
+		  LastLongLink.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongLink.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 case GNU_LongName:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length < sizeof(Block))
+	       {
+		  LastLongName.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongName.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 default:
+	 BadRecord = true;
+	 _error->Warning(_("Unknown TAR header type %u"), (unsigned)Tar->LinkFlag);
+	 break;
+      }
+
+      int Fd = -1;
+      if (not BadRecord && not Stream.DoItem(Itm, Fd))
+	 return false;
+
+      if (Fd == -1 || Fd < -2 || BadRecord)
+      {
+	 if (Itm.Size > 0 && not InFd.Skip(((Itm.Size + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	    return false;
+      }
+      else if (Itm.Size != 0)
+      {
+	 // Copy the file over the FD
+	 auto Size = Itm.Size;
+	 unsigned char Junk[32*1024];
+	 do
+	 {
+	    auto const Read = std::min<unsigned long long>(Size, sizeof(Junk));
+	    if (not InFd.Read(Junk, ((Read + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	       return false;
+
+	    if (Fd > 0)
+	    {
+	       if (not FileFd::Write(Fd, Junk, Read))
+		  return Stream.Fail(Itm, Fd);
+	    }
+	    // An Fd of -2 means to send to a special processing function
+	    else if (Fd == -2)
+	    {
+	       if (not Stream.Process(Itm, Junk, Read, Itm.Size - Size))
+		  return Stream.Fail(Itm, Fd);
+	    }
+
+	    Size -= Read;
+	 } while (Size != 0);
+      }
+
+      // And finish up
+      if (not BadRecord && not Stream.FinishedFile(Itm, Fd))
+	 return false;
+      LastLongName.erase();
+      LastLongLink.erase();
+   }
+
+   return Done();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/extracttar.h b/apt-pkg/contrib/extracttar.h
new file mode 100644
index 0000000..a3c862a
--- /dev/null
+++ b/apt-pkg/contrib/extracttar.h
@@ -0,0 +1,55 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Extract a Tar - Tar Extractor
+   
+   The tar extractor takes an ordinary gzip compressed tar stream from 
+   the given file and explodes it, passing the individual items to the
+   given Directory Stream for processing.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EXTRACTTAR_H
+#define PKGLIB_EXTRACTTAR_H
+
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+
+#include <string>
+
+
+class pkgDirStream;
+
+class APT_PUBLIC ExtractTar
+{
+   protected:
+   
+   struct TarHeader;
+   
+   // The varios types items can be
+   enum ItemType {NormalFile0 = '\0',NormalFile = '0',HardLink = '1',
+                  SymbolicLink = '2',CharacterDevice = '3',
+                  BlockDevice = '4',Directory = '5',FIFO = '6',
+                  GNU_LongLink = 'K',GNU_LongName = 'L'};
+
+   FileFd &File;
+   unsigned long long MaxInSize;
+   int GZPid;
+   FileFd InFd;
+   bool Eof;
+   std::string DecompressProg;
+   
+   // Fork and reap gzip
+   bool StartGzip();
+   bool Done();
+
+   public:
+
+   bool Go(pkgDirStream &Stream);
+
+   ExtractTar(FileFd &Fd,unsigned long long Max,std::string DecompressionProgram);
+   virtual ~ExtractTar();
+};
+
+#endif
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
new file mode 100644
index 0000000..fad51de
--- /dev/null
+++ b/apt-pkg/contrib/fileutl.cc
@@ -0,0 +1,3483 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   File Utilities
+   
+   CopyFile - Buffered copy of a single file
+   GetLock - dpkg compatible lock file manipulation (fcntl)
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Most of this source is placed in the Public Domain, do with it what 
+   you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+   FileFd gzip support added by Martin Pitt <martin.pitt@canonical.com>
+   
+   The exception is RunScripts() it is under the GPLv2
+
+   We believe that this reference to GPLv2 was not meant to exclude later
+   versions as that would have changed the overall project license from GPL-2+
+   to GPL-2.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/strutl.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <glob.h>
+#include <grp.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <memory>
+#include <set>
+
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+#endif
+#ifdef HAVE_BZ2
+#include <bzlib.h>
+#endif
+#ifdef HAVE_LZMA
+#include <lzma.h>
+#endif
+#ifdef HAVE_LZ4
+#include <lz4frame.h>
+#endif
+#ifdef HAVE_ZSTD
+#include <zstd.h>
+#endif
+#ifdef HAVE_SYSTEMD
+#include <systemd/sd-bus.h>
+#endif
+#include <endian.h>
+#include <stdint.h>
+
+#if __gnu_linux__
+#include <sys/prctl.h>
+#endif
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// RunScripts - Run a set of scripts from a configuration subtree	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RunScripts(const char *Cnf)
+{
+   Configuration::Item const *Opts = _config->Tree(Cnf);
+   if (Opts == 0 || Opts->Child == 0)
+      return true;
+   Opts = Opts->Child;
+
+   // Fork for running the system calls
+   pid_t Child = ExecFork();
+   
+   // This is the child
+   if (Child == 0)
+   {
+      if (_system != nullptr && _system->IsLocked() == true && (stringcasecmp(Cnf, "dpkg::post-invoke") == 0 || stringcasecmp(Cnf, "dpkg::pre-invoke") == 0))
+	 setenv("DPKG_FRONTEND_LOCKED", "true", 1);
+      if (_config->FindDir("DPkg::Chroot-Directory","/") != "/") 
+      {
+         std::cerr << "Chrooting into " 
+                   << _config->FindDir("DPkg::Chroot-Directory") 
+                   << std::endl;
+         if (chroot(_config->FindDir("DPkg::Chroot-Directory","/").c_str()) != 0)
+            _exit(100);
+      }
+
+      if (chdir("/tmp/") != 0)
+	 _exit(100);
+	 
+      unsigned int Count = 1;
+      for (; Opts != 0; Opts = Opts->Next, Count++)
+      {
+	 if (Opts->Value.empty() == true)
+	    continue;
+
+         if(_config->FindB("Debug::RunScripts", false) == true)
+            std::clog << "Running external script: '"
+                      << Opts->Value << "'" << std::endl;
+
+	 if (system(Opts->Value.c_str()) != 0)
+	    _exit(100+Count);
+      }
+      _exit(0);
+   }      
+
+   // Wait for the child
+   int Status = 0;
+   while (waitpid(Child,&Status,0) != Child)
+   {
+      if (errno == EINTR)
+	 continue;
+      return _error->Errno("waitpid","Couldn't wait for subprocess");
+   }
+
+   // Check for an error code.
+   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
+   {
+      unsigned int Count = WEXITSTATUS(Status);
+      if (Count > 100)
+      {
+	 Count -= 100;
+	 for (; Opts != 0 && Count != 1; Opts = Opts->Next, Count--);
+	 _error->Error("Problem executing scripts %s '%s'",Cnf,Opts->Value.c_str());
+      }
+      
+      return _error->Error("Sub-process returned an error code");
+   }
+   
+   return true;
+}
+									/*}}}*/
+
+// CopyFile - Buffered copy of a file					/*{{{*/
+// ---------------------------------------------------------------------
+/* The caller is expected to set things so that failure causes erasure */
+bool CopyFile(FileFd &From,FileFd &To)
+{
+   if (From.IsOpen() == false || To.IsOpen() == false ||
+	 From.Failed() == true || To.Failed() == true)
+      return false;
+
+   // Buffered copy between fds
+   constexpr size_t BufSize = APT_BUFFER_SIZE;
+   std::unique_ptr<unsigned char[]> Buf(new unsigned char[BufSize]);
+   unsigned long long ToRead = 0;
+   do {
+      if (From.Read(Buf.get(),BufSize, &ToRead) == false ||
+	  To.Write(Buf.get(),ToRead) == false)
+	 return false;
+   } while (ToRead != 0);
+
+   return true;
+}
+									/*}}}*/
+bool RemoveFileAt(char const * const Function, int const dirfd, std::string const &FileName)/*{{{*/
+{
+   if (FileName == "/dev/null")
+      return true;
+   errno = 0;
+   if (unlinkat(dirfd, FileName.c_str(), 0) != 0)
+   {
+      if (errno == ENOENT)
+	 return true;
+
+      return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+bool RemoveFile(char const * const Function, std::string const &FileName)/*{{{*/
+{
+   if (FileName == "/dev/null")
+      return true;
+   errno = 0;
+   if (unlink(FileName.c_str()) != 0)
+   {
+      if (errno == ENOENT)
+	 return true;
+
+      return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// GetLock - Gets a lock file						/*{{{*/
+// ---------------------------------------------------------------------
+/* This will create an empty file of the given name and lock it. Once this
+   is done all other calls to GetLock in any other process will fail with
+   -1. The return result is the fd of the file, the call should call
+   close at some time. */
+
+static std::string GetProcessName(int pid)
+{
+   struct HideError
+   {
+      int err;
+      HideError() : err(errno) { _error->PushToStack(); }
+      ~HideError()
+      {
+	 errno = err;
+	 _error->RevertToStack();
+      }
+   } hideError;
+   std::string path;
+   strprintf(path, "/proc/%d/status", pid);
+   FileFd status(path, FileFd::ReadOnly);
+   std::string line;
+   while (status.ReadLine(line))
+   {
+      if (line.substr(0, 5) == "Name:")
+	 return line.substr(6);
+   }
+   return "";
+}
+int GetLock(string File,bool Errors)
+{
+   // GetLock() is used in aptitude on directories with public-write access
+   // Use O_NOFOLLOW here to prevent symlink traversal attacks
+   int FD = open(File.c_str(),O_RDWR | O_CREAT | O_NOFOLLOW,0640);
+   if (FD < 0)
+   {
+      // Read only .. can't have locking problems there.
+      if (errno == EROFS)
+      {
+	 _error->Warning(_("Not using locking for read only lock file %s"),File.c_str());
+	 return dup(0);       // Need something for the caller to close
+      }
+      
+      if (Errors == true)
+	 _error->Errno("open",_("Could not open lock file %s"),File.c_str());
+
+      // Feh.. We do this to distinguish the lock vs open case..
+      errno = EPERM;
+      return -1;
+   }
+   SetCloseExec(FD,true);
+      
+   // Acquire a write lock
+   struct flock fl;
+   fl.l_type = F_WRLCK;
+   fl.l_whence = SEEK_SET;
+   fl.l_start = 0;
+   fl.l_len = 0;
+   if (fcntl(FD,F_SETLK,&fl) == -1)
+   {
+      // always close to not leak resources
+      int Tmp = errno;
+
+      if ((errno == EACCES || errno == EAGAIN))
+      {
+	 fl.l_type = F_WRLCK;
+	 fl.l_whence = SEEK_SET;
+	 fl.l_start = 0;
+	 fl.l_len = 0;
+	 fl.l_pid = -1;
+	 fcntl(FD, F_GETLK, &fl);
+      }
+      else
+      {
+	 fl.l_pid = -1;
+      }
+      close(FD);
+      errno = Tmp;
+
+      if (errno == ENOLCK)
+      {
+	 _error->Warning(_("Not using locking for nfs mounted lock file %s"),File.c_str());
+	 return dup(0);       // Need something for the caller to close	 
+      }
+  
+      if (Errors == true)
+      {
+	 // We only do the lookup in the if ((errno == EACCES || errno == EAGAIN))
+	 // case, so we do not need to show the errno strerrr here...
+	 if (fl.l_pid != -1)
+	 {
+	    auto name = GetProcessName(fl.l_pid);
+	    if (name.empty())
+	       _error->Error(_("Could not get lock %s. It is held by process %d"), File.c_str(), fl.l_pid);
+	    else
+	       _error->Error(_("Could not get lock %s. It is held by process %d (%s)"), File.c_str(), fl.l_pid, name.c_str());
+	 }
+	 else
+	    _error->Errno("open", _("Could not get lock %s"), File.c_str());
+
+	 _error->Notice(_("Be aware that removing the lock file is not a solution and may break your system."));
+      }
+
+      return -1;
+   }
+
+   return FD;
+}
+									/*}}}*/
+// FileExists - Check if a file exists					/*{{{*/
+// ---------------------------------------------------------------------
+/* Beware: Directories are also files! */
+bool FileExists(string File)
+{
+   struct stat Buf;
+   if (stat(File.c_str(),&Buf) != 0)
+      return false;
+   return true;
+}
+									/*}}}*/
+// RealFileExists - Check if a file exists and if it is really a file	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RealFileExists(string File)
+{
+   struct stat Buf;
+   if (stat(File.c_str(),&Buf) != 0)
+      return false;
+   return ((Buf.st_mode & S_IFREG) != 0);
+}
+									/*}}}*/
+// DirectoryExists - Check if a directory exists and is really one	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool DirectoryExists(string const &Path)
+{
+   struct stat Buf;
+   if (stat(Path.c_str(),&Buf) != 0)
+      return false;
+   return ((Buf.st_mode & S_IFDIR) != 0);
+}
+									/*}}}*/
+// CreateDirectory - poor man's mkdir -p guarded by a parent directory	/*{{{*/
+// ---------------------------------------------------------------------
+/* This method will create all directories needed for path in good old
+   mkdir -p style but refuses to do this if Parent is not a prefix of
+   this Path. Example: /var/cache/ and /var/cache/apt/archives are given,
+   so it will create apt/archives if /var/cache exists - on the other
+   hand if the parent is /var/lib the creation will fail as this path
+   is not a parent of the path to be generated. */
+bool CreateDirectory(string const &Parent, string const &Path)
+{
+   if (Parent.empty() == true || Path.empty() == true)
+      return false;
+
+   if (DirectoryExists(Path) == true)
+      return true;
+
+   if (DirectoryExists(Parent) == false)
+      return false;
+
+   // we are not going to create directories "into the blue"
+   if (Path.compare(0, Parent.length(), Parent) != 0)
+      return false;
+
+   vector<string> const dirs = VectorizeString(Path.substr(Parent.size()), '/');
+   string progress = Parent;
+   for (vector<string>::const_iterator d = dirs.begin(); d != dirs.end(); ++d)
+   {
+      if (d->empty() == true)
+	 continue;
+
+      progress.append("/").append(*d);
+      if (DirectoryExists(progress) == true)
+	 continue;
+
+      if (mkdir(progress.c_str(), 0755) != 0)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+// CreateAPTDirectoryIfNeeded - ensure that the given directory exists		/*{{{*/
+// ---------------------------------------------------------------------
+/* a small wrapper around CreateDirectory to check if it exists and to
+   remove the trailing "/apt/" from the parent directory if needed */
+bool CreateAPTDirectoryIfNeeded(string const &Parent, string const &Path)
+{
+   if (DirectoryExists(Path) == true)
+      return true;
+
+   size_t const len = Parent.size();
+   if (len > 5 && Parent.find("/apt/", len - 6, 5) == len - 5)
+   {
+      if (CreateDirectory(Parent.substr(0,len-5), Path) == true)
+	 return true;
+   }
+   else if (CreateDirectory(Parent, Path) == true)
+      return true;
+
+   return false;
+}
+									/*}}}*/
+// GetListOfFilesInDir - returns a vector of files in the given dir	/*{{{*/
+// ---------------------------------------------------------------------
+/* If an extension is given only files with this extension are included
+   in the returned vector, otherwise every "normal" file is included. */
+std::vector<string> GetListOfFilesInDir(string const &Dir, string const &Ext,
+					bool const &SortList, bool const &AllowNoExt)
+{
+   std::vector<string> ext;
+   ext.reserve(2);
+   if (Ext.empty() == false)
+      ext.push_back(Ext);
+   if (AllowNoExt == true && ext.empty() == false)
+      ext.push_back("");
+   return GetListOfFilesInDir(Dir, ext, SortList);
+}
+std::vector<string> GetListOfFilesInDir(string const &Dir, std::vector<string> const &Ext,
+					bool const &SortList)
+{
+   // Attention debuggers: need to be set with the environment config file!
+   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
+   if (Debug == true)
+   {
+      std::clog << "Accept in " << Dir << " only files with the following " << Ext.size() << " extensions:" << std::endl;
+      if (Ext.empty() == true)
+	 std::clog << "\tNO extension" << std::endl;
+      else
+	 for (std::vector<string>::const_iterator e = Ext.begin();
+	      e != Ext.end(); ++e)
+	    std::clog << '\t' << (e->empty() == true ? "NO" : *e) << " extension" << std::endl;
+   }
+
+   std::vector<string> List;
+
+   if (DirectoryExists(Dir) == false)
+   {
+      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
+      return List;
+   }
+
+   Configuration::MatchAgainstConfig SilentIgnore("Dir::Ignore-Files-Silently");
+   DIR *D = opendir(Dir.c_str());
+   if (D == 0) 
+   {
+      if (errno == EACCES)
+	 _error->WarningE("opendir", _("Unable to read %s"), Dir.c_str());
+      else
+	 _error->Errno("opendir", _("Unable to read %s"), Dir.c_str());
+      return List;
+   }
+
+   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
+   {
+      // skip "hidden" files
+      if (Ent->d_name[0] == '.')
+	 continue;
+
+      // Make sure it is a file and not something else
+      string const File = flCombine(Dir,Ent->d_name);
+#ifdef _DIRENT_HAVE_D_TYPE
+      if (Ent->d_type != DT_REG)
+#endif
+      {
+	 if (RealFileExists(File) == false)
+	 {
+	    // do not show ignoration warnings for directories
+	    if (
+#ifdef _DIRENT_HAVE_D_TYPE
+		Ent->d_type == DT_DIR ||
+#endif
+		DirectoryExists(File) == true)
+	       continue;
+	    if (SilentIgnore.Match(Ent->d_name) == false)
+	       _error->Notice(_("Ignoring '%s' in directory '%s' as it is not a regular file"), Ent->d_name, Dir.c_str());
+	    continue;
+	 }
+      }
+
+      // check for accepted extension:
+      // no extension given -> periods are bad as hell!
+      // extensions given -> "" extension allows no extension
+      if (Ext.empty() == false)
+      {
+	 string d_ext = flExtension(Ent->d_name);
+	 if (d_ext == Ent->d_name) // no extension
+	 {
+	    if (std::find(Ext.begin(), Ext.end(), "") == Ext.end())
+	    {
+	       if (Debug == true)
+		  std::clog << "Bad file: " << Ent->d_name << " → no extension" << std::endl;
+	       if (SilentIgnore.Match(Ent->d_name) == false)
+		  _error->Notice(_("Ignoring file '%s' in directory '%s' as it has no filename extension"), Ent->d_name, Dir.c_str());
+	       continue;
+	    }
+	 }
+	 else if (std::find(Ext.begin(), Ext.end(), d_ext) == Ext.end())
+	 {
+	    if (Debug == true)
+	       std::clog << "Bad file: " << Ent->d_name << " → bad extension »" << flExtension(Ent->d_name) << "«" << std::endl;
+	    if (SilentIgnore.Match(Ent->d_name) == false)
+	       _error->Notice(_("Ignoring file '%s' in directory '%s' as it has an invalid filename extension"), Ent->d_name, Dir.c_str());
+	    continue;
+	 }
+      }
+
+      // Skip bad filenames ala run-parts
+      const char *C = Ent->d_name;
+      for (; *C != 0; ++C)
+	 if (isalpha(*C) == 0 && isdigit(*C) == 0
+	     && *C != '_' && *C != '-' && *C != ':') {
+	    // no required extension -> dot is a bad character
+	    if (*C == '.' && Ext.empty() == false)
+	       continue;
+	    break;
+	 }
+
+      // we don't reach the end of the name -> bad character included
+      if (*C != 0)
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → bad character »"
+	       << *C << "« in filename (period allowed: " << (Ext.empty() ? "no" : "yes") << ")" << std::endl;
+	 continue;
+      }
+
+      // skip filenames which end with a period. These are never valid
+      if (*(C - 1) == '.')
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
+	 continue;
+      }
+
+      if (Debug == true)
+	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
+      List.push_back(File);
+   }
+   closedir(D);
+
+   if (SortList == true)
+      std::sort(List.begin(),List.end());
+   return List;
+}
+std::vector<string> GetListOfFilesInDir(string const &Dir, bool SortList)
+{
+   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
+   if (Debug == true)
+      std::clog << "Accept in " << Dir << " all regular files" << std::endl;
+
+   std::vector<string> List;
+
+   if (DirectoryExists(Dir) == false)
+   {
+      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
+      return List;
+   }
+
+   DIR *D = opendir(Dir.c_str());
+   if (D == 0)
+   {
+      _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
+      return List;
+   }
+
+   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
+   {
+      // skip "hidden" files
+      if (Ent->d_name[0] == '.')
+	 continue;
+
+      // Make sure it is a file and not something else
+      string const File = flCombine(Dir,Ent->d_name);
+#ifdef _DIRENT_HAVE_D_TYPE
+      if (Ent->d_type != DT_REG)
+#endif
+      {
+	 if (RealFileExists(File) == false)
+	 {
+	    if (Debug == true)
+	       std::clog << "Bad file: " << Ent->d_name << " → it is not a real file" << std::endl;
+	    continue;
+	 }
+      }
+
+      // Skip bad filenames ala run-parts
+      const char *C = Ent->d_name;
+      for (; *C != 0; ++C)
+	 if (isalpha(*C) == 0 && isdigit(*C) == 0
+	     && *C != '_' && *C != '-' && *C != '.')
+	    break;
+
+      // we don't reach the end of the name -> bad character included
+      if (*C != 0)
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → bad character »" << *C << "« in filename" << std::endl;
+	 continue;
+      }
+
+      // skip filenames which end with a period. These are never valid
+      if (*(C - 1) == '.')
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
+	 continue;
+      }
+
+      if (Debug == true)
+	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
+      List.push_back(File);
+   }
+   closedir(D);
+
+   if (SortList == true)
+      std::sort(List.begin(),List.end());
+   return List;
+}
+									/*}}}*/
+// SafeGetCWD - This is a safer getcwd that returns a dynamic string	/*{{{*/
+// ---------------------------------------------------------------------
+/* We return / on failure. */
+string SafeGetCWD()
+{
+   // Stash the current dir.
+   char S[300];
+   S[0] = 0;
+   if (getcwd(S,sizeof(S)-2) == 0)
+      return "/";
+   unsigned int Len = strlen(S);
+   S[Len] = '/';
+   S[Len+1] = 0;
+   return S;
+}
+									/*}}}*/
+// GetModificationTime - Get the mtime of the given file or -1 on error /*{{{*/
+// ---------------------------------------------------------------------
+/* We return / on failure. */
+time_t GetModificationTime(string const &Path)
+{
+   struct stat St;
+   if (stat(Path.c_str(), &St) < 0)
+      return -1;
+   return  St.st_mtime;
+}
+									/*}}}*/
+// flNotDir - Strip the directory from the filename			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flNotDir(string File)
+{
+   string::size_type Res = File.rfind('/');
+   if (Res == string::npos)
+      return File;
+   Res++;
+   return string(File,Res,Res - File.length());
+}
+									/*}}}*/
+// flNotFile - Strip the file from the directory name			/*{{{*/
+// ---------------------------------------------------------------------
+/* Result ends in a / */
+string flNotFile(string File)
+{
+   string::size_type Res = File.rfind('/');
+   if (Res == string::npos)
+      return "./";
+   Res++;
+   return string(File,0,Res);
+}
+									/*}}}*/
+// flExtension - Return the extension for the file			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flExtension(string File)
+{
+   string::size_type Res = File.rfind('.');
+   if (Res == string::npos)
+      return File;
+   Res++;
+   return string(File,Res);
+}
+									/*}}}*/
+// flNoLink - If file is a symlink then deref it			/*{{{*/
+// ---------------------------------------------------------------------
+/* If the name is not a link then the returned path is the input. */
+string flNoLink(string File)
+{
+   struct stat St;
+   if (lstat(File.c_str(),&St) != 0 || S_ISLNK(St.st_mode) == 0)
+      return File;
+   if (stat(File.c_str(),&St) != 0)
+      return File;
+   
+   /* Loop resolving the link. There is no need to limit the number of 
+      loops because the stat call above ensures that the symlink is not 
+      circular */
+   char Buffer[1024];
+   string NFile = File;
+   while (1)
+   {
+      // Read the link
+      ssize_t Res;
+      if ((Res = readlink(NFile.c_str(),Buffer,sizeof(Buffer))) <= 0 || 
+	  (size_t)Res >= sizeof(Buffer))
+	  return File;
+      
+      // Append or replace the previous path
+      Buffer[Res] = 0;
+      if (Buffer[0] == '/')
+	 NFile = Buffer;
+      else
+	 NFile = flNotFile(NFile) + Buffer;
+      
+      // See if we are done
+      if (lstat(NFile.c_str(),&St) != 0)
+	 return File;
+      if (S_ISLNK(St.st_mode) == 0)
+	 return NFile;      
+   }   
+}
+									/*}}}*/
+// flCombine - Combine a file and a directory				/*{{{*/
+// ---------------------------------------------------------------------
+/* If the file is an absolute path then it is just returned, otherwise
+   the directory is pre-pended to it. */
+string flCombine(string Dir,string File)
+{
+   if (File.empty() == true)
+      return string();
+   
+   if (File[0] == '/' || Dir.empty() == true)
+      return File;
+   if (File.length() >= 2 && File[0] == '.' && File[1] == '/')
+      return File;
+   if (Dir[Dir.length()-1] == '/')
+      return Dir + File;
+   return Dir + '/' + File;
+}
+									/*}}}*/
+// flAbsPath - Return the absolute path of the filename			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flAbsPath(string File)
+{
+   char *p = realpath(File.c_str(), NULL);
+   if (p == NULL)
+   {
+      _error->Errno("realpath", "flAbsPath on %s failed", File.c_str());
+      return "";
+   }
+   std::string AbsPath(p);
+   free(p);
+   return AbsPath;
+}
+									/*}}}*/
+std::string flNormalize(std::string file)				/*{{{*/
+{
+   if (file.empty())
+      return file;
+   // do some normalisation by removing // and /./ from the path
+   size_t found = string::npos;
+   while ((found = file.find("/./")) != string::npos)
+      file.replace(found, 3, "/");
+   while ((found = file.find("//")) != string::npos)
+      file.replace(found, 2, "/");
+
+   if (APT::String::Startswith(file, "/dev/null"))
+   {
+      file.erase(strlen("/dev/null"));
+      return file;
+   }
+   return file;
+}
+									/*}}}*/
+// SetCloseExec - Set the close on exec flag				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void SetCloseExec(int Fd,bool Close)
+{   
+   if (fcntl(Fd,F_SETFD,(Close == false)?0:FD_CLOEXEC) != 0)
+   {
+      cerr << "FATAL -> Could not set close on exec " << strerror(errno) << endl;
+      exit(100);
+   }
+}
+									/*}}}*/
+// SetNonBlock - Set the nonblocking flag				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void SetNonBlock(int Fd,bool Block)
+{   
+   int Flags = fcntl(Fd,F_GETFL) & (~O_NONBLOCK);
+   if (fcntl(Fd,F_SETFL,Flags | ((Block == false)?0:O_NONBLOCK)) != 0)
+   {
+      cerr << "FATAL -> Could not set non-blocking flag " << strerror(errno) << endl;
+      exit(100);
+   }
+}
+									/*}}}*/
+// WaitFd - Wait for a FD to become readable				/*{{{*/
+// ---------------------------------------------------------------------
+/* This waits for a FD to become readable using select. It is useful for
+   applications making use of non-blocking sockets. The timeout is 
+   in seconds. */
+bool WaitFd(int Fd,bool write,unsigned long timeout)
+{
+   fd_set Set;
+   struct timeval tv;
+   FD_ZERO(&Set);
+   FD_SET(Fd,&Set);
+   tv.tv_sec = timeout;
+   tv.tv_usec = 0;
+   if (write == true) 
+   {      
+      int Res;
+      do
+      {
+	 Res = select(Fd+1,0,&Set,0,(timeout != 0?&tv:0));
+      }
+      while (Res < 0 && errno == EINTR);
+      
+      if (Res <= 0)
+	 return false;
+   } 
+   else 
+   {
+      int Res;
+      do
+      {
+	 Res = select(Fd+1,&Set,0,0,(timeout != 0?&tv:0));
+      }
+      while (Res < 0 && errno == EINTR);
+      
+      if (Res <= 0)
+	 return false;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// MergeKeepFdsFromConfiguration - Merge APT::Keep-Fds configuration	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to merge the APT::Keep-Fds with the provided KeepFDs
+ * set.
+ */
+void MergeKeepFdsFromConfiguration(std::set<int> &KeepFDs)
+{
+      Configuration::Item const *Opts = _config->Tree("APT::Keep-Fds");
+      if (Opts != 0 && Opts->Child != 0)
+      {
+	 Opts = Opts->Child;
+	 for (; Opts != 0; Opts = Opts->Next)
+	 {
+	    if (Opts->Value.empty() == true)
+	       continue;
+	    int fd = atoi(Opts->Value.c_str());
+	    KeepFDs.insert(fd);
+	 }
+      }
+}
+									/*}}}*/
+// ExecFork - Magical fork that sanitizes the context before execing	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used if you want to cleanse the environment for the forked 
+   child, it fixes up the important signals and nukes all of the fds,
+   otherwise acts like normal fork. */
+pid_t ExecFork()
+{
+      set<int> KeepFDs;
+      // we need to merge the Keep-Fds as external tools like 
+      // debconf-apt-progress use it
+      MergeKeepFdsFromConfiguration(KeepFDs);
+      return ExecFork(KeepFDs);
+}
+
+pid_t ExecFork(std::set<int> KeepFDs)
+{
+   // Fork off the process
+   pid_t Process = fork();
+   if (Process < 0)
+   {
+      cerr << "FATAL -> Failed to fork." << endl;
+      exit(100);
+   }
+
+   // Spawn the subprocess
+   if (Process == 0)
+   {
+      // Setup the signals
+      signal(SIGPIPE,SIG_DFL);
+      signal(SIGQUIT,SIG_DFL);
+      signal(SIGINT,SIG_DFL);
+      signal(SIGWINCH,SIG_DFL);
+      signal(SIGCONT,SIG_DFL);
+      signal(SIGTSTP,SIG_DFL);
+
+      DIR *dir = opendir("/proc/self/fd");
+      if (dir != NULL)
+      {
+	 struct dirent *ent;
+	 while ((ent = readdir(dir)))
+	 {
+	    int fd = atoi(ent->d_name);
+	    // If fd > 0, it was a fd number and not . or ..
+	    if (fd >= 3 && KeepFDs.find(fd) == KeepFDs.end())
+	       fcntl(fd,F_SETFD,FD_CLOEXEC);
+	 }
+	 closedir(dir);
+      } else {
+	 long ScOpenMax = sysconf(_SC_OPEN_MAX);
+	 // Close all of our FDs - just in case
+	 for (int K = 3; K != ScOpenMax; K++)
+	 {
+	    if(KeepFDs.find(K) == KeepFDs.end())
+	       fcntl(K,F_SETFD,FD_CLOEXEC);
+	 }
+      }
+   }
+   
+   return Process;
+}
+									/*}}}*/
+// ExecWait - Fancy waitpid						/*{{{*/
+// ---------------------------------------------------------------------
+/* Waits for the given sub process. If Reap is set then no errors are 
+   generated. Otherwise a failed subprocess will generate a proper descriptive
+   message */
+bool ExecWait(pid_t Pid,const char *Name,bool Reap)
+{
+   if (Pid <= 1)
+      return true;
+   
+   // Wait and collect the error code
+   int Status;
+   while (waitpid(Pid,&Status,0) != Pid)
+   {
+      if (errno == EINTR)
+	 continue;
+
+      if (Reap == true)
+	 return false;
+      
+      return _error->Error(_("Waited for %s but it wasn't there"),Name);
+   }
+
+   
+   // Check for an error code.
+   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
+   {
+      if (Reap == true)
+	 return false;
+      if (WIFSIGNALED(Status) != 0)
+      {
+	 if( WTERMSIG(Status) == SIGSEGV)
+	    return _error->Error(_("Sub-process %s received a segmentation fault."),Name);
+	 else 
+	    return _error->Error(_("Sub-process %s received signal %u."),Name, WTERMSIG(Status));
+      }
+
+      if (WIFEXITED(Status) != 0)
+	 return _error->Error(_("Sub-process %s returned an error code (%u)"),Name,WEXITSTATUS(Status));
+      
+      return _error->Error(_("Sub-process %s exited unexpectedly"),Name);
+   }      
+   
+   return true;
+}
+									/*}}}*/
+// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned	/*{{{*/
+bool StartsWithGPGClearTextSignature(string const &FileName)
+{
+   FILE* gpg = fopen(FileName.c_str(), "r");
+   if (gpg == nullptr)
+      return false;
+
+   char * lineptr = nullptr;
+   size_t n = 0;
+   errno = 0;
+   ssize_t const result = getline(&lineptr, &n, gpg);
+   if (errno != 0)
+   {
+      _error->Errno("getline", "Could not read from %s", FileName.c_str());
+      fclose(gpg);
+      free(lineptr);
+      return false;
+   }
+   fclose(gpg);
+
+   _strrstrip(lineptr);
+   static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----";
+   if (result == -1 || strcmp(lineptr, SIGMSG) != 0)
+   {
+      free(lineptr);
+      return false;
+   }
+   free(lineptr);
+   return true;
+}
+									/*}}}*/
+// ChangeOwnerAndPermissionOfFile - set file attributes to requested values /*{{{*/
+bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode)
+{
+   if (strcmp(file, "/dev/null") == 0)
+      return true;
+   bool Res = true;
+   if (getuid() == 0 && strlen(user) != 0 && strlen(group) != 0) // if we aren't root, we can't chown, so don't try it
+   {
+      // ensure the file is owned by root and has good permissions
+      struct passwd const * const pw = getpwnam(user);
+      struct group const * const gr = getgrnam(group);
+      if (pw != NULL && gr != NULL && lchown(file, pw->pw_uid, gr->gr_gid) != 0)
+	 Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file);
+   }
+   struct stat Buf;
+   if (lstat(file, &Buf) != 0 || S_ISLNK(Buf.st_mode))
+      return Res;
+   if (chmod(file, mode) != 0)
+      Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file);
+   return Res;
+}
+									/*}}}*/
+
+struct APT_HIDDEN simple_buffer {							/*{{{*/
+   size_t buffersize_max = 0;
+   unsigned long long bufferstart = 0;
+   unsigned long long bufferend = 0;
+   char *buffer = nullptr;
+
+   simple_buffer() {
+      reset(4096);
+   }
+   ~simple_buffer() {
+      delete[] buffer;
+   }
+
+   const char *get() const { return buffer + bufferstart; }
+   char *get() { return buffer + bufferstart; }
+   const char *getend() const { return buffer + bufferend; }
+   char *getend() { return buffer + bufferend; }
+   bool empty() const { return bufferend <= bufferstart; }
+   bool full() const { return bufferend == buffersize_max; }
+   unsigned long long free() const { return buffersize_max - bufferend; }
+   unsigned long long size() const { return bufferend-bufferstart; }
+   void reset(size_t size)
+   {
+      if (size > buffersize_max) {
+	 delete[] buffer;
+	 buffersize_max = size;
+	 buffer = new char[size];
+      }
+      reset();
+   }
+   void reset() { bufferend = bufferstart = 0; }
+   ssize_t read(void *to, unsigned long long requested_size) APT_MUSTCHECK
+   {
+      if (size() < requested_size)
+	 requested_size = size();
+      memcpy(to, buffer + bufferstart, requested_size);
+      bufferstart += requested_size;
+      if (bufferstart == bufferend)
+	 bufferstart = bufferend = 0;
+      return requested_size;
+   }
+   ssize_t write(const void *from, unsigned long long requested_size) APT_MUSTCHECK
+   {
+      if (free() < requested_size)
+	 requested_size = free();
+      memcpy(getend(), from, requested_size);
+      bufferend += requested_size;
+      if (bufferstart == bufferend)
+	 bufferstart = bufferend = 0;
+      return requested_size;
+   }
+};
+									/*}}}*/
+
+class APT_HIDDEN FileFdPrivate {							/*{{{*/
+   friend class BufferedWriteFileFdPrivate;
+protected:
+   FileFd * const filefd;
+   simple_buffer buffer;
+   int compressed_fd;
+   pid_t compressor_pid;
+   bool is_pipe;
+   APT::Configuration::Compressor compressor;
+   unsigned int openmode;
+   unsigned long long seekpos;
+public:
+
+   explicit FileFdPrivate(FileFd * const pfilefd) : filefd(pfilefd),
+      compressed_fd(-1), compressor_pid(-1), is_pipe(false),
+      openmode(0), seekpos(0) {};
+   virtual APT::Configuration::Compressor get_compressor() const
+   {
+      return compressor;
+   }
+   virtual void set_compressor(APT::Configuration::Compressor const &compressor)
+   {
+      this->compressor = compressor;
+   }
+   virtual unsigned int get_openmode() const
+   {
+      return openmode;
+   }
+   virtual void set_openmode(unsigned int openmode)
+   {
+      this->openmode = openmode;
+   }
+   virtual bool get_is_pipe() const
+   {
+      return is_pipe;
+   }
+   virtual void set_is_pipe(bool is_pipe)
+   {
+      this->is_pipe = is_pipe;
+   }
+   virtual unsigned long long get_seekpos() const
+   {
+      return seekpos;
+   }
+   virtual void set_seekpos(unsigned long long seekpos)
+   {
+      this->seekpos = seekpos;
+   }
+
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) = 0;
+   ssize_t InternalRead(void * To, unsigned long long Size)
+   {
+      // Drain the buffer if needed.
+      if (buffer.empty() == false)
+      {
+	 return buffer.read(To, Size);
+      }
+      return InternalUnbufferedRead(To, Size);
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) = 0;
+   virtual bool InternalReadError() { return filefd->FileFdErrno("read",_("Read error")); }
+   virtual char * InternalReadLine(char * To, unsigned long long Size)
+   {
+      if (unlikely(Size == 0))
+	 return nullptr;
+      // Read one byte less than buffer size to have space for trailing 0.
+      --Size;
+
+      char * const InitialTo = To;
+
+      while (Size > 0) {
+	 if (buffer.empty() == true)
+	 {
+	    buffer.reset();
+	    unsigned long long actualread = 0;
+	    if (filefd->Read(buffer.getend(), buffer.free(), &actualread) == false)
+	       return nullptr;
+	    buffer.bufferend = actualread;
+	    if (buffer.size() == 0)
+	    {
+	       if (To == InitialTo)
+		  return nullptr;
+	       break;
+	    }
+	    filefd->Flags &= ~FileFd::HitEof;
+	 }
+
+	 unsigned long long const OutputSize = std::min(Size, buffer.size());
+	 char const * const newline = static_cast<char const *>(memchr(buffer.get(), '\n', OutputSize));
+	 // Read until end of line or up to Size bytes from the buffer.
+	 unsigned long long actualread = buffer.read(To,
+						     (newline != nullptr)
+						     ? (newline - buffer.get()) + 1
+						     : OutputSize);
+	 To += actualread;
+	 Size -= actualread;
+	 if (newline != nullptr)
+	    break;
+      }
+      *To = '\0';
+      return InitialTo;
+   }
+   virtual bool InternalFlush()
+   {
+      return true;
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) = 0;
+   virtual bool InternalWriteError() { return filefd->FileFdErrno("write",_("Write error")); }
+   virtual bool InternalSeek(unsigned long long const To)
+   {
+      // Our poor man seeking is costly, so try to avoid it
+      unsigned long long const iseekpos = filefd->Tell();
+      if (iseekpos == To)
+	 return true;
+      else if (iseekpos < To)
+	 return filefd->Skip(To - iseekpos);
+
+      if ((openmode & FileFd::ReadOnly) != FileFd::ReadOnly)
+	 return filefd->FileFdError("Reopen is only implemented for read-only files!");
+      InternalClose(filefd->FileName);
+      if (filefd->iFd != -1)
+	 close(filefd->iFd);
+      filefd->iFd = -1;
+      if (filefd->TemporaryFileName.empty() == false)
+	 filefd->iFd = open(filefd->TemporaryFileName.c_str(), O_RDONLY);
+      else if (filefd->FileName.empty() == false)
+	 filefd->iFd = open(filefd->FileName.c_str(), O_RDONLY);
+      else
+      {
+	 if (compressed_fd > 0)
+	    if (lseek(compressed_fd, 0, SEEK_SET) != 0)
+	       filefd->iFd = compressed_fd;
+	 if (filefd->iFd < 0)
+	    return filefd->FileFdError("Reopen is not implemented for pipes opened with FileFd::OpenDescriptor()!");
+      }
+
+      if (filefd->OpenInternDescriptor(openmode, compressor) == false)
+	 return filefd->FileFdError("Seek on file %s because it couldn't be reopened", filefd->FileName.c_str());
+
+      buffer.reset();
+      set_seekpos(0);
+      if (To != 0)
+	 return filefd->Skip(To);
+
+      seekpos = To;
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over)
+   {
+      unsigned long long constexpr buffersize = 1024;
+      char buffer[buffersize];
+      while (Over != 0)
+      {
+	 unsigned long long toread = std::min(buffersize, Over);
+	 if (filefd->Read(buffer, toread) == false)
+	    return filefd->FileFdError("Unable to seek ahead %llu",Over);
+	 Over -= toread;
+      }
+      return true;
+   }
+   virtual bool InternalTruncate(unsigned long long const)
+   {
+      return filefd->FileFdError("Truncating compressed files is not implemented (%s)", filefd->FileName.c_str());
+   }
+   virtual unsigned long long InternalTell()
+   {
+      // In theory, we could just return seekpos here always instead of
+      // seeking around, but not all users of FileFd use always Seek() and co
+      // so d->seekpos isn't always true and we can just use it as a hint if
+      // we have nothing else, but not always as an authority…
+      return seekpos - buffer.size();
+   }
+   virtual unsigned long long InternalSize()
+   {
+      unsigned long long size = 0;
+      unsigned long long const oldSeek = filefd->Tell();
+      unsigned long long constexpr ignoresize = 1024;
+      char ignore[ignoresize];
+      unsigned long long read = 0;
+      do {
+	 if (filefd->Read(ignore, ignoresize, &read) == false)
+	 {
+	    filefd->Seek(oldSeek);
+	    return 0;
+	 }
+      } while(read != 0);
+      size = filefd->Tell();
+      filefd->Seek(oldSeek);
+      return size;
+   }
+   virtual bool InternalClose(std::string const &FileName) = 0;
+   virtual bool InternalStream() const { return false; }
+   virtual bool InternalAlwaysAutoClose() const { return true; }
+
+   virtual ~FileFdPrivate() {}
+};
+									/*}}}*/
+class APT_HIDDEN BufferedWriteFileFdPrivate : public FileFdPrivate {	/*{{{*/
+protected:
+   FileFdPrivate *wrapped;
+   simple_buffer writebuffer;
+
+public:
+
+   explicit BufferedWriteFileFdPrivate(FileFdPrivate *Priv) :
+      FileFdPrivate(Priv->filefd), wrapped(Priv) {};
+
+   virtual APT::Configuration::Compressor get_compressor() const APT_OVERRIDE
+   {
+      return wrapped->get_compressor();
+   }
+   virtual void set_compressor(APT::Configuration::Compressor const &compressor)  APT_OVERRIDE
+   {
+      return wrapped->set_compressor(compressor);
+   }
+   virtual unsigned int get_openmode() const  APT_OVERRIDE
+   {
+      return wrapped->get_openmode();
+   }
+   virtual void set_openmode(unsigned int openmode)  APT_OVERRIDE
+   {
+      return wrapped->set_openmode(openmode);
+   }
+   virtual bool get_is_pipe() const  APT_OVERRIDE
+   {
+      return wrapped->get_is_pipe();
+   }
+   virtual void set_is_pipe(bool is_pipe) APT_OVERRIDE
+   {
+      FileFdPrivate::set_is_pipe(is_pipe);
+      wrapped->set_is_pipe(is_pipe);
+   }
+   virtual unsigned long long get_seekpos() const APT_OVERRIDE
+   {
+      return wrapped->get_seekpos();
+   }
+   virtual void set_seekpos(unsigned long long seekpos) APT_OVERRIDE
+   {
+      return wrapped->set_seekpos(seekpos);
+   }
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalOpen(iFd, Mode);
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalUnbufferedRead(To, Size);
+
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      return wrapped->InternalReadError();
+   }
+   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return nullptr;
+      return wrapped->InternalReadLine(To, Size);
+   }
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      while (writebuffer.empty() == false) {
+	 auto written = wrapped->InternalWrite(writebuffer.get(),
+					       writebuffer.size());
+	 // Ignore interrupted syscalls
+	 if (written < 0 && errno == EINTR)
+	    continue;
+	 if (written < 0)
+	    return wrapped->InternalWriteError();
+
+	 writebuffer.bufferstart += written;
+      }
+      writebuffer.reset();
+      return wrapped->InternalFlush();
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // Optimisation: If the buffer is empty and we have more to write than
+      // would fit in the buffer (or equal number of bytes), write directly.
+      if (writebuffer.empty() == true && Size >= writebuffer.free())
+	 return wrapped->InternalWrite(From, Size);
+
+      // Write as much into the buffer as possible and then flush if needed
+      auto written = writebuffer.write(From, Size);
+
+      if (writebuffer.full() && InternalFlush() == false)
+	 return -1;
+
+      return written;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      return wrapped->InternalWriteError();
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalSeek(To);
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalSkip(Over);
+   }
+   virtual bool InternalTruncate(unsigned long long const Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalTruncate(Size);
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalTell();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalSize();
+   }
+   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
+   {
+      return wrapped->InternalClose(FileName);
+   }
+   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE
+   {
+      return wrapped->InternalAlwaysAutoClose();
+   }
+   virtual ~BufferedWriteFileFdPrivate()
+   {
+      delete wrapped;
+   }
+};
+									/*}}}*/
+class APT_HIDDEN GzipFileFdPrivate: public FileFdPrivate {				/*{{{*/
+#ifdef HAVE_ZLIB
+public:
+   gzFile gz;
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 gz = gzdopen(iFd, "r+");
+      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 gz = gzdopen(iFd, "w");
+      else
+	 gz = gzdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      return gz != nullptr;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return gzread(gz, To, Size);
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = gzerror(gz, &err);
+      if (err != Z_ERRNO)
+	 return filefd->FileFdError("gzread: %s (%d: %s)", _("Read error"), err, errmsg);
+      return FileFdPrivate::InternalReadError();
+   }
+   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
+   {
+      return gzgets(gz, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return gzwrite(gz,From,Size);
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = gzerror(gz, &err);
+      if (err != Z_ERRNO)
+	 return filefd->FileFdError("gzwrite: %s (%d: %s)", _("Write error"), err, errmsg);
+      return FileFdPrivate::InternalWriteError();
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      off_t const res = gzseek(gz, To, SEEK_SET);
+      if (res != (off_t)To)
+	 return filefd->FileFdError("Unable to seek to %llu", To);
+      seekpos = To;
+      buffer.reset();
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (Over >= buffer.size())
+      {
+	 Over -= buffer.size();
+	 buffer.reset();
+      }
+      else
+      {
+	 buffer.bufferstart += Over;
+	 return true;
+      }
+      if (Over == 0)
+	 return true;
+      off_t const res = gzseek(gz, Over, SEEK_CUR);
+      if (res < 0)
+	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
+      seekpos = res;
+      return true;
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      return gztell(gz) - buffer.size();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      unsigned long long filesize = FileFdPrivate::InternalSize();
+      // only check gzsize if we are actually a gzip file, just checking for
+      // "gz" is not sufficient as uncompressed files could be opened with
+      // gzopen in "direct" mode as well
+      if (filesize == 0 || gzdirect(gz))
+	 return filesize;
+
+      off_t const oldPos = lseek(filefd->iFd, 0, SEEK_CUR);
+      /* unfortunately zlib.h doesn't provide a gzsize(), so we have to do
+       * this ourselves; the original (uncompressed) file size is the last 32
+       * bits of the file */
+      // FIXME: Size for gz-files is limited by 32bit… no largefile support
+      if (lseek(filefd->iFd, -4, SEEK_END) < 0)
+      {
+	 filefd->FileFdErrno("lseek","Unable to seek to end of gzipped file");
+	 return 0;
+      }
+      uint32_t size = 0;
+      if (read(filefd->iFd, &size, 4) != 4)
+      {
+	 filefd->FileFdErrno("read","Unable to read original size of gzipped file");
+	 return 0;
+      }
+      size = le32toh(size);
+
+      if (lseek(filefd->iFd, oldPos, SEEK_SET) < 0)
+      {
+	 filefd->FileFdErrno("lseek","Unable to seek in gzipped file");
+	 return 0;
+      }
+      return size;
+   }
+   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
+   {
+      if (gz == nullptr)
+	 return true;
+      int const e = gzclose(gz);
+      gz = nullptr;
+      // gzdclose() on empty files always fails with "buffer error" here, ignore that
+      if (e != 0 && e != Z_BUF_ERROR)
+	 return _error->Errno("close",_("Problem closing the gzip file %s"), FileName.c_str());
+      return true;
+   }
+
+   explicit GzipFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), gz(nullptr) {}
+   virtual ~GzipFileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN Bz2FileFdPrivate: public FileFdPrivate {				/*{{{*/
+#ifdef HAVE_BZ2
+   BZFILE* bz2;
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 bz2 = BZ2_bzdopen(iFd, "r+");
+      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 bz2 = BZ2_bzdopen(iFd, "w");
+      else
+	 bz2 = BZ2_bzdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      return bz2 != nullptr;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return BZ2_bzread(bz2, To, Size);
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = BZ2_bzerror(bz2, &err);
+      if (err != BZ_IO_ERROR)
+	 return filefd->FileFdError("BZ2_bzread: %s %s (%d: %s)", filefd->FileName.c_str(), _("Read error"), err, errmsg);
+      return FileFdPrivate::InternalReadError();
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return BZ2_bzwrite(bz2, (void*)From, Size);
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = BZ2_bzerror(bz2, &err);
+      if (err != BZ_IO_ERROR)
+	 return filefd->FileFdError("BZ2_bzwrite: %s %s (%d: %s)", filefd->FileName.c_str(), _("Write error"), err, errmsg);
+      return FileFdPrivate::InternalWriteError();
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      if (bz2 == nullptr)
+	 return true;
+      BZ2_bzclose(bz2);
+      bz2 = nullptr;
+      return true;
+   }
+
+   explicit Bz2FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), bz2(nullptr) {}
+   virtual ~Bz2FileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN Lz4FileFdPrivate: public FileFdPrivate {				/*{{{*/
+   static constexpr unsigned long long LZ4_HEADER_SIZE = 19;
+   static constexpr unsigned long long LZ4_FOOTER_SIZE = 4;
+#ifdef HAVE_LZ4
+   LZ4F_decompressionContext_t dctx;
+   LZ4F_compressionContext_t cctx;
+   LZ4F_errorCode_t res;
+   FileFd backend;
+   simple_buffer lz4_buffer;
+   // Count of bytes that the decompressor expects to read next, or buffer size.
+   size_t next_to_load = APT_BUFFER_SIZE;
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return _error->Error("lz4 only supports write or read mode");
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly) {
+	 res = LZ4F_createCompressionContext(&cctx, LZ4F_VERSION);
+	 lz4_buffer.reset(LZ4F_compressBound(APT_BUFFER_SIZE, nullptr)
+			  + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE);
+      } else {
+	 res = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);
+	 lz4_buffer.reset(APT_BUFFER_SIZE);
+      }
+
+      filefd->Flags |= FileFd::Compressed;
+
+      if (LZ4F_isError(res))
+	 return false;
+
+      unsigned int flags = (Mode & (FileFd::WriteOnly|FileFd::ReadOnly));
+      if (backend.OpenDescriptor(iFd, flags, FileFd::None, true) == false)
+	 return false;
+
+      // Write the file header
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 res = LZ4F_compressBegin(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
+	 if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	    return false;
+      }
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      /* Keep reading as long as the compressor still wants to read */
+      while (next_to_load) {
+	 // Fill compressed buffer;
+	 if (lz4_buffer.empty()) {
+	    unsigned long long read;
+	    /* Reset - if LZ4 decompressor wants to read more, allocate more */
+	    lz4_buffer.reset(next_to_load);
+	    if (backend.Read(lz4_buffer.getend(), lz4_buffer.free(), &read) == false)
+	       return -1;
+	    lz4_buffer.bufferend += read;
+
+	    /* Expected EOF */
+	    if (read == 0) {
+	       res = -1;
+	       return filefd->FileFdError("LZ4F: %s %s",
+					  filefd->FileName.c_str(),
+					  _("Unexpected end of file")), -1;
+	    }
+	 }
+	 // Drain compressed buffer as far as possible.
+	 size_t in = lz4_buffer.size();
+	 size_t out = Size;
+
+	 res = LZ4F_decompress(dctx, To, &out, lz4_buffer.get(), &in, nullptr);
+	 if (LZ4F_isError(res))
+	       return -1;
+
+	 next_to_load = res;
+	 lz4_buffer.bufferstart += in;
+
+	 if (out != 0)
+	    return out;
+      }
+
+      return 0;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      char const * const errmsg = LZ4F_getErrorName(res);
+
+      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Read error"), res, errmsg);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      unsigned long long const towrite = std::min(APT_BUFFER_SIZE, Size);
+
+      res = LZ4F_compressUpdate(cctx,
+				lz4_buffer.buffer, lz4_buffer.buffersize_max,
+				From, towrite, nullptr);
+
+      if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	 return -1;
+
+      return towrite;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      char const * const errmsg = LZ4F_getErrorName(res);
+
+      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Write error"), res, errmsg);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      return backend.Flush();
+   }
+
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      /* Reset variables */
+      res = 0;
+      next_to_load = APT_BUFFER_SIZE;
+
+      if (cctx != nullptr)
+      {
+	 if (filefd->Failed() == false)
+	 {
+	    res = LZ4F_compressEnd(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
+	    if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	       return false;
+	    if (!backend.Flush())
+	       return false;
+	 }
+	 if (!backend.Close())
+	    return false;
+
+	 res = LZ4F_freeCompressionContext(cctx);
+	 cctx = nullptr;
+      }
+
+      if (dctx != nullptr)
+      {
+	 res = LZ4F_freeDecompressionContext(dctx);
+	 dctx = nullptr;
+      }
+      if (backend.IsOpen())
+      {
+	 backend.Close();
+	 filefd->iFd = -1;
+      }
+
+      return LZ4F_isError(res) == false;
+   }
+
+   explicit Lz4FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), dctx(nullptr), cctx(nullptr) {}
+   virtual ~Lz4FileFdPrivate() {
+      InternalClose("");
+   }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN ZstdFileFdPrivate : public FileFdPrivate		/*{{{*/
+{
+#ifdef HAVE_ZSTD
+   ZSTD_DStream *dctx;
+   ZSTD_CStream *cctx;
+   size_t res = 0;
+   FileFd backend;
+   simple_buffer zstd_buffer;
+   // Count of bytes that the decompressor expects to read next, or buffer size.
+   size_t next_to_load = APT_BUFFER_SIZE;
+
+   public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return _error->Error("zstd only supports write or read mode");
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 cctx = ZSTD_createCStream();
+	 res = ZSTD_initCStream(cctx, findLevel(compressor.CompressArgs));
+	 zstd_buffer.reset(APT_BUFFER_SIZE);
+      }
+      else
+      {
+	 dctx = ZSTD_createDStream();
+	 res = ZSTD_initDStream(dctx);
+	 zstd_buffer.reset(APT_BUFFER_SIZE);
+      }
+
+      filefd->Flags |= FileFd::Compressed;
+
+      if (ZSTD_isError(res))
+	 return false;
+
+      unsigned int flags = (Mode & (FileFd::WriteOnly | FileFd::ReadOnly));
+      if (backend.OpenDescriptor(iFd, flags, FileFd::None, true) == false)
+	 return false;
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void *const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      /* Keep reading as long as the compressor still wants to read */
+      while (true)
+      {
+	 // Fill compressed buffer;
+	 if (zstd_buffer.empty())
+	 {
+	    unsigned long long read;
+	    /* Reset - if LZ4 decompressor wants to read more, allocate more */
+	    zstd_buffer.reset(next_to_load);
+	    if (backend.Read(zstd_buffer.getend(), zstd_buffer.free(), &read) == false)
+	       return -1;
+	    zstd_buffer.bufferend += read;
+
+	    if (read == 0)
+	    {
+	       /* Expected EOF */
+	       if (next_to_load == 0)
+		  return 0;
+
+	       res = -1;
+	       return filefd->FileFdError("ZSTD: %s %s",
+					  filefd->FileName.c_str(),
+					  _("Unexpected end of file")),
+		      -1;
+	    }
+	 }
+	 // Drain compressed buffer as far as possible.
+	 ZSTD_inBuffer in = {
+	    .src = zstd_buffer.get(),
+	    .size = zstd_buffer.size(),
+	    .pos = 0,
+	 };
+	 ZSTD_outBuffer out = {
+	    .dst = To,
+	    .size = Size,
+	    .pos = 0,
+	 };
+
+	 next_to_load = res = ZSTD_decompressStream(dctx, &out, &in);
+
+	 if (res == 0)
+	 {
+	    res = ZSTD_initDStream(dctx);
+	 }
+
+	 if (ZSTD_isError(res))
+	    return -1;
+
+	 zstd_buffer.bufferstart += in.pos;
+
+	 if (out.pos != 0)
+	    return out.pos;
+      }
+
+      return 0;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      char const *const errmsg = ZSTD_getErrorName(res);
+
+      return filefd->FileFdError("ZSTD: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Read error"), res, errmsg);
+   }
+   virtual ssize_t InternalWrite(void const *const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // Drain compressed buffer as far as possible.
+      ZSTD_outBuffer out = {
+	 .dst = zstd_buffer.buffer,
+	 .size = zstd_buffer.buffersize_max,
+	 .pos = 0,
+      };
+      ZSTD_inBuffer in = {
+	 .src = From,
+	 .size = Size,
+	 .pos = 0,
+      };
+
+      res = ZSTD_compressStream(cctx, &out, &in);
+
+      if (ZSTD_isError(res) || backend.Write(zstd_buffer.buffer, out.pos) == false)
+	 return -1;
+
+      return in.pos;
+   }
+
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      char const *const errmsg = ZSTD_getErrorName(res);
+
+      return filefd->FileFdError("ZSTD: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Write error"), res, errmsg);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      return backend.Flush();
+   }
+
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      /* Reset variables */
+      res = 0;
+      next_to_load = APT_BUFFER_SIZE;
+
+      if (cctx != nullptr)
+      {
+	 if (filefd->Failed() == false)
+	 {
+	    do
+	    {
+	       ZSTD_outBuffer out = {
+		  .dst = zstd_buffer.buffer,
+		  .size = zstd_buffer.buffersize_max,
+		  .pos = 0,
+	       };
+	       res = ZSTD_endStream(cctx, &out);
+	       if (ZSTD_isError(res) || backend.Write(zstd_buffer.buffer, out.pos) == false)
+		  return false;
+	    } while (res > 0);
+
+	    if (!backend.Flush())
+	       return false;
+	 }
+	 if (!backend.Close())
+	    return false;
+
+	 res = ZSTD_freeCStream(cctx);
+	 cctx = nullptr;
+      }
+
+      if (dctx != nullptr)
+      {
+	 res = ZSTD_freeDStream(dctx);
+	 dctx = nullptr;
+      }
+      if (backend.IsOpen())
+      {
+	 backend.Close();
+	 filefd->iFd = -1;
+      }
+
+      return ZSTD_isError(res) == false;
+   }
+
+   static uint32_t findLevel(std::vector<std::string> const &Args)
+   {
+      for (auto a = Args.rbegin(); a != Args.rend(); ++a)
+      {
+	 if (a->size() >= 2 && (*a)[0] == '-' && (*a)[1] != '-')
+	 {
+	    auto const level = a->substr(1);
+	    auto const notANumber = level.find_first_not_of("0123456789");
+	    if (notANumber != std::string::npos)
+	       continue;
+
+	    return (uint32_t)stoi(level);
+	 }
+      }
+      return 19;
+   }
+
+   explicit ZstdFileFdPrivate(FileFd *const filefd) : FileFdPrivate(filefd), dctx(nullptr), cctx(nullptr) {}
+   virtual ~ZstdFileFdPrivate()
+   {
+      InternalClose("");
+   }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN LzmaFileFdPrivate: public FileFdPrivate {		/*{{{*/
+#ifdef HAVE_LZMA
+   struct LZMAFILE {
+      FILE* file;
+      FileFd * const filefd;
+      uint8_t buffer[4096];
+      lzma_stream stream;
+      lzma_ret err;
+      bool eof;
+      bool compressing;
+
+      explicit LZMAFILE(FileFd * const fd) : file(nullptr), filefd(fd), eof(false), compressing(false) { buffer[0] = '\0'; }
+      ~LZMAFILE()
+      {
+	 if (compressing == true && filefd->Failed() == false)
+	 {
+	    size_t constexpr buffersize = sizeof(buffer)/sizeof(buffer[0]);
+	    while(true)
+	    {
+	       stream.avail_out = buffersize;
+	       stream.next_out = buffer;
+	       err = lzma_code(&stream, LZMA_FINISH);
+	       if (err != LZMA_OK && err != LZMA_STREAM_END)
+	       {
+		  _error->Error("~LZMAFILE: Compress finalisation failed");
+		  break;
+	       }
+	       size_t const n =  buffersize - stream.avail_out;
+	       if (n && fwrite(buffer, 1, n, file) != n)
+	       {
+		  _error->Errno("~LZMAFILE",_("Write error"));
+		  break;
+	       }
+	       if (err == LZMA_STREAM_END)
+		  break;
+	    }
+	 }
+	 lzma_end(&stream);
+	 fclose(file);
+      }
+   };
+   LZMAFILE* lzma;
+   static uint32_t findXZlevel(std::vector<std::string> const &Args)
+   {
+      for (auto a = Args.rbegin(); a != Args.rend(); ++a)
+	 if (a->empty() == false && (*a)[0] == '-' && (*a)[1] != '-')
+	 {
+	    auto const number = a->find_last_of("0123456789");
+	    if (number == std::string::npos)
+	       continue;
+	    auto const extreme = a->find("e", number);
+	    uint32_t level = (extreme != std::string::npos) ? LZMA_PRESET_EXTREME : 0;
+	    switch ((*a)[number])
+	    {
+	       case '0': return level | 0;
+	       case '1': return level | 1;
+	       case '2': return level | 2;
+	       case '3': return level | 3;
+	       case '4': return level | 4;
+	       case '5': return level | 5;
+	       case '6': return level | 6;
+	       case '7': return level | 7;
+	       case '8': return level | 8;
+	       case '9': return level | 9;
+	    }
+	 }
+      return 6;
+   }
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return filefd->FileFdError("ReadWrite mode is not supported for lzma/xz files %s", filefd->FileName.c_str());
+
+      if (lzma == nullptr)
+	 lzma = new LzmaFileFdPrivate::LZMAFILE(filefd);
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 lzma->file = fdopen(iFd, "w");
+      else
+	 lzma->file = fdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      if (lzma->file == nullptr)
+	 return false;
+
+      lzma_stream tmp_stream = LZMA_STREAM_INIT;
+      lzma->stream = tmp_stream;
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 uint32_t const xzlevel = findXZlevel(compressor.CompressArgs);
+	 if (compressor.Name == "xz")
+	 {
+	    if (lzma_easy_encoder(&lzma->stream, xzlevel, LZMA_CHECK_CRC64) != LZMA_OK)
+	       return false;
+	 }
+	 else
+	 {
+	    lzma_options_lzma options;
+	    lzma_lzma_preset(&options, xzlevel);
+	    if (lzma_alone_encoder(&lzma->stream, &options) != LZMA_OK)
+	       return false;
+	 }
+	 lzma->compressing = true;
+      }
+      else
+      {
+	 uint64_t constexpr memlimit = 1024 * 1024 * 500;
+	 if (lzma_auto_decoder(&lzma->stream, memlimit, 0) != LZMA_OK)
+	    return false;
+	 lzma->compressing = false;
+      }
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      ssize_t Res;
+      if (lzma->eof == true)
+	 return 0;
+
+      lzma->stream.next_out = (uint8_t *) To;
+      lzma->stream.avail_out = Size;
+      if (lzma->stream.avail_in == 0)
+      {
+	 lzma->stream.next_in = lzma->buffer;
+	 lzma->stream.avail_in = fread(lzma->buffer, 1, sizeof(lzma->buffer)/sizeof(lzma->buffer[0]), lzma->file);
+      }
+      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
+      if (lzma->err == LZMA_STREAM_END)
+      {
+	 lzma->eof = true;
+	 Res = Size - lzma->stream.avail_out;
+      }
+      else if (lzma->err != LZMA_OK)
+      {
+	 Res = -1;
+	 errno = 0;
+      }
+      else
+      {
+	 Res = Size - lzma->stream.avail_out;
+	 if (Res == 0)
+	 {
+	    // lzma run was okay, but produced no output…
+	    Res = -1;
+	    errno = EINTR;
+	 }
+      }
+      return Res;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      return filefd->FileFdError("lzma_read: %s (%d)", _("Read error"), lzma->err);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      ssize_t Res;
+      lzma->stream.next_in = (uint8_t *)From;
+      lzma->stream.avail_in = Size;
+      lzma->stream.next_out = lzma->buffer;
+      lzma->stream.avail_out = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]);
+      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
+      if (lzma->err != LZMA_OK)
+	 return -1;
+      size_t const n = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]) - lzma->stream.avail_out;
+      size_t const m = (n == 0) ? 0 : fwrite(lzma->buffer, 1, n, lzma->file);
+      if (m != n)
+      {
+	 Res = -1;
+	 errno = 0;
+      }
+      else
+      {
+	 Res = Size - lzma->stream.avail_in;
+	 if (Res == 0)
+	 {
+	    // lzma run was okay, but produced no output…
+	    Res = -1;
+	    errno = EINTR;
+	 }
+      }
+      return Res;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      return filefd->FileFdError("lzma_write: %s (%d)", _("Write error"), lzma->err);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      delete lzma;
+      lzma = nullptr;
+      return true;
+   }
+
+   explicit LzmaFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), lzma(nullptr) {}
+   virtual ~LzmaFileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN PipedFileFdPrivate: public FileFdPrivate				/*{{{*/
+/* if we don't have a specific class dealing with library calls, we (un)compress
+   by executing a specified binary and pipe in/out what we need */
+{
+public:
+   virtual bool InternalOpen(int const, unsigned int const Mode) APT_OVERRIDE
+   {
+      // collect zombies here in case we reopen
+      if (compressor_pid > 0)
+	 ExecWait(compressor_pid, "FileFdCompressor", true);
+
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return filefd->FileFdError("ReadWrite mode is not supported for file %s", filefd->FileName.c_str());
+      if (compressor.Binary == "false")
+	 return filefd->FileFdError("libapt has inbuilt support for the %s compression,"
+	       " but was forced to ignore it in favor of an external binary – which isn't installed.", compressor.Name.c_str());
+
+      bool const Comp = (Mode & FileFd::WriteOnly) == FileFd::WriteOnly;
+      if (Comp == false && filefd->iFd != -1)
+      {
+	 // Handle 'decompression' of empty files
+	 struct stat Buf;
+	 if (fstat(filefd->iFd, &Buf) != 0)
+	    return filefd->FileFdErrno("fstat", "Could not stat fd %d for file %s", filefd->iFd, filefd->FileName.c_str());
+	 if (Buf.st_size == 0 && S_ISFIFO(Buf.st_mode) == false)
+	    return true;
+
+	 // We don't need the file open - instead let the compressor open it
+	 // as he properly knows better how to efficiently read from 'his' file
+	 if (filefd->FileName.empty() == false)
+	 {
+	    close(filefd->iFd);
+	    filefd->iFd = -1;
+	 }
+      }
+
+      // Create a data pipe
+      int Pipe[2] = {-1,-1};
+      if (pipe(Pipe) != 0)
+	 return filefd->FileFdErrno("pipe",_("Failed to create subprocess IPC"));
+      for (int J = 0; J != 2; J++)
+	 SetCloseExec(Pipe[J],true);
+
+      compressed_fd = filefd->iFd;
+      set_is_pipe(true);
+
+      if (Comp == true)
+	 filefd->iFd = Pipe[1];
+      else
+	 filefd->iFd = Pipe[0];
+
+      // The child..
+      compressor_pid = ExecFork();
+      if (compressor_pid == 0)
+      {
+	 if (Comp == true)
+	 {
+	    dup2(compressed_fd,STDOUT_FILENO);
+	    dup2(Pipe[0],STDIN_FILENO);
+	 }
+	 else
+	 {
+	    if (compressed_fd != -1)
+	       dup2(compressed_fd,STDIN_FILENO);
+	    dup2(Pipe[1],STDOUT_FILENO);
+	 }
+	 int const nullfd = open("/dev/null", O_WRONLY);
+	 if (nullfd != -1)
+	 {
+	    dup2(nullfd,STDERR_FILENO);
+	    close(nullfd);
+	 }
+
+	 SetCloseExec(STDOUT_FILENO,false);
+	 SetCloseExec(STDIN_FILENO,false);
+
+	 std::vector<char const*> Args;
+	 Args.push_back(compressor.Binary.c_str());
+	 std::vector<std::string> const * const addArgs =
+	    (Comp == true) ? &(compressor.CompressArgs) : &(compressor.UncompressArgs);
+	 for (std::vector<std::string>::const_iterator a = addArgs->begin();
+	       a != addArgs->end(); ++a)
+	    Args.push_back(a->c_str());
+	 if (Comp == false && filefd->FileName.empty() == false)
+	 {
+	    // commands not needing arguments, do not need to be told about using standard output
+	    // in reality, only testcases with tools like cat, rev, rot13, … are able to trigger this
+	    if (compressor.CompressArgs.empty() == false && compressor.UncompressArgs.empty() == false)
+	       Args.push_back("--stdout");
+	    if (filefd->TemporaryFileName.empty() == false)
+	       Args.push_back(filefd->TemporaryFileName.c_str());
+	    else
+	       Args.push_back(filefd->FileName.c_str());
+	 }
+	 Args.push_back(NULL);
+
+	 execvp(Args[0],(char **)&Args[0]);
+	 cerr << _("Failed to exec compressor ") << Args[0] << endl;
+	 _exit(100);
+      }
+      if (Comp == true)
+	 close(Pipe[0]);
+      else
+	 close(Pipe[1]);
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return read(filefd->iFd, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return write(filefd->iFd, From, Size);
+   }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      bool Ret = true;
+      if (filefd->iFd != -1)
+      {
+	 close(filefd->iFd);
+	 filefd->iFd = -1;
+      }
+      if (compressor_pid > 0)
+	 Ret &= ExecWait(compressor_pid, "FileFdCompressor", true);
+      compressor_pid = -1;
+      return Ret;
+   }
+   explicit PipedFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
+   virtual ~PipedFileFdPrivate() { InternalClose(""); }
+};
+									/*}}}*/
+class APT_HIDDEN DirectFileFdPrivate: public FileFdPrivate				/*{{{*/
+{
+public:
+   virtual bool InternalOpen(int const, unsigned int const) APT_OVERRIDE { return true; }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return read(filefd->iFd, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // files opened read+write are strange and only really "supported" for direct files
+      if (buffer.size() != 0)
+      {
+	 lseek(filefd->iFd, -buffer.size(), SEEK_CUR);
+	 buffer.reset();
+      }
+      return write(filefd->iFd, From, Size);
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      off_t const res = lseek(filefd->iFd, To, SEEK_SET);
+      if (res != (off_t)To)
+	 return filefd->FileFdError("Unable to seek to %llu", To);
+      seekpos = To;
+      buffer.reset();
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (Over >= buffer.size())
+      {
+	 Over -= buffer.size();
+	 buffer.reset();
+      }
+      else
+      {
+	 buffer.bufferstart += Over;
+	 return true;
+      }
+      if (Over == 0)
+	 return true;
+      off_t const res = lseek(filefd->iFd, Over, SEEK_CUR);
+      if (res < 0)
+	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
+      seekpos = res;
+      return true;
+   }
+   virtual bool InternalTruncate(unsigned long long const To) APT_OVERRIDE
+   {
+      if (buffer.size() != 0)
+      {
+	 unsigned long long const seekpos = lseek(filefd->iFd, 0, SEEK_CUR);
+	 if ((seekpos - buffer.size()) >= To)
+	    buffer.reset();
+	 else if (seekpos >= To)
+	    buffer.bufferend = (To - seekpos) + buffer.bufferstart;
+	 else
+	    buffer.reset();
+      }
+      if (ftruncate(filefd->iFd, To) != 0)
+	 return filefd->FileFdError("Unable to truncate to %llu",To);
+      return true;
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      return lseek(filefd->iFd,0,SEEK_CUR) - buffer.size();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      return filefd->FileSize();
+   }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE { return true; }
+   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE { return false; }
+
+   explicit DirectFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
+   virtual ~DirectFileFdPrivate() { InternalClose(""); }
+};
+									/*}}}*/
+// FileFd Constructors							/*{{{*/
+FileFd::FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
+{
+   Open(FileName,Mode, None, AccessMode);
+}
+FileFd::FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
+{
+   Open(FileName,Mode, Compress, AccessMode);
+}
+FileFd::FileFd() : iFd(-1), Flags(AutoClose), d(NULL) {}
+FileFd::FileFd(int const Fd, unsigned int const Mode, CompressMode Compress) : iFd(-1), Flags(0), d(NULL)
+{
+   OpenDescriptor(Fd, Mode, Compress);
+}
+FileFd::FileFd(int const Fd, bool const AutoClose) : iFd(-1), Flags(0), d(NULL)
+{
+   OpenDescriptor(Fd, ReadWrite, None, AutoClose);
+}
+									/*}}}*/
+// FileFd::Open - Open a file						/*{{{*/
+// ---------------------------------------------------------------------
+/* The most commonly used open mode combinations are given with Mode */
+bool FileFd::Open(string FileName,unsigned int const Mode,CompressMode Compress, unsigned long const AccessMode)
+{
+   if (Mode == ReadOnlyGzip)
+      return Open(FileName, ReadOnly, Gzip, AccessMode);
+
+   if (Compress == Auto && (Mode & WriteOnly) == WriteOnly)
+      return FileFdError("Autodetection on %s only works in ReadOnly openmode!", FileName.c_str());
+
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   if (Compress == Auto)
+   {
+      for (; compressor != compressors.end(); ++compressor)
+      {
+	 std::string file = FileName + compressor->Extension;
+	 if (FileExists(file) == false)
+	    continue;
+	 FileName = file;
+	 break;
+      }
+   }
+   else if (Compress == Extension)
+   {
+      std::string::size_type const found = FileName.find_last_of('.');
+      std::string ext;
+      if (found != std::string::npos)
+      {
+	 ext = FileName.substr(found);
+	 if (ext == ".new" || ext == ".bak")
+	 {
+	    std::string::size_type const found2 = FileName.find_last_of('.', found - 1);
+	    if (found2 != std::string::npos)
+	       ext = FileName.substr(found2, found - found2);
+	    else
+	       ext.clear();
+	 }
+      }
+      for (; compressor != compressors.end(); ++compressor)
+	 if (ext == compressor->Extension)
+	    break;
+      // no matching extension - assume uncompressed (imagine files like 'example.org_Packages')
+      if (compressor == compressors.end())
+	 for (compressor = compressors.begin(); compressor != compressors.end(); ++compressor)
+	    if (compressor->Name == ".")
+	       break;
+   }
+   else
+   {
+      std::string name;
+      switch (Compress)
+      {
+      case None: name = "."; break;
+      case Gzip: name = "gzip"; break;
+      case Bzip2: name = "bzip2"; break;
+      case Lzma: name = "lzma"; break;
+      case Xz: name = "xz"; break;
+      case Lz4: name = "lz4"; break;
+      case Zstd: name = "zstd"; break;
+      case Auto:
+      case Extension:
+	 // Unreachable
+	 return FileFdError("Opening File %s in None, Auto or Extension should be already handled?!?", FileName.c_str());
+      }
+      for (; compressor != compressors.end(); ++compressor)
+	 if (compressor->Name == name)
+	    break;
+      if (compressor == compressors.end())
+	 return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
+   }
+
+   if (compressor == compressors.end())
+      return FileFdError("Can't find a match for specified compressor mode for file %s", FileName.c_str());
+   return Open(FileName, Mode, *compressor, AccessMode);
+}
+bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Compressor const &compressor, unsigned long const AccessMode)
+{
+   Close();
+   Flags = AutoClose;
+
+   if ((Mode & WriteOnly) != WriteOnly && (Mode & (Atomic | Create | Empty | Exclusive)) != 0)
+      return FileFdError("ReadOnly mode for %s doesn't accept additional flags!", FileName.c_str());
+   if ((Mode & ReadWrite) == 0)
+      return FileFdError("No openmode provided in FileFd::Open for %s", FileName.c_str());
+
+   unsigned int OpenMode = Mode;
+   if (FileName == "/dev/null")
+      OpenMode = OpenMode & ~(Atomic | Exclusive | Create | Empty);
+
+   if ((OpenMode & Atomic) == Atomic)
+   {
+      Flags |= Replace;
+   }
+   else if ((OpenMode & (Exclusive | Create)) == (Exclusive | Create))
+   {
+      // for atomic, this will be done by rename in Close()
+      RemoveFile("FileFd::Open", FileName);
+   }
+   if ((OpenMode & Empty) == Empty)
+   {
+      struct stat Buf;
+      if (lstat(FileName.c_str(),&Buf) == 0 && S_ISLNK(Buf.st_mode))
+	 RemoveFile("FileFd::Open", FileName);
+   }
+
+   int fileflags = 0;
+   #define if_FLAGGED_SET(FLAG, MODE) if ((OpenMode & FLAG) == FLAG) fileflags |= MODE
+   if_FLAGGED_SET(ReadWrite, O_RDWR);
+   else if_FLAGGED_SET(ReadOnly, O_RDONLY);
+   else if_FLAGGED_SET(WriteOnly, O_WRONLY);
+
+   if_FLAGGED_SET(Create, O_CREAT);
+   if_FLAGGED_SET(Empty, O_TRUNC);
+   if_FLAGGED_SET(Exclusive, O_EXCL);
+   #undef if_FLAGGED_SET
+
+   if ((OpenMode & Atomic) == Atomic)
+   {
+      char *name = strdup((FileName + ".XXXXXX").c_str());
+
+      if((iFd = mkstemp(name)) == -1)
+      {
+          free(name);
+          return FileFdErrno("mkstemp", "Could not create temporary file for %s", FileName.c_str());
+      }
+
+      TemporaryFileName = string(name);
+      free(name);
+
+      // umask() will always set the umask and return the previous value, so
+      // we first set the umask and then reset it to the old value
+      mode_t const CurrentUmask = umask(0);
+      umask(CurrentUmask);
+      // calculate the actual file permissions (just like open/creat)
+      mode_t const FilePermissions = (AccessMode & ~CurrentUmask);
+
+      if(fchmod(iFd, FilePermissions) == -1)
+          return FileFdErrno("fchmod", "Could not change permissions for temporary file %s", TemporaryFileName.c_str());
+   }
+   else
+      iFd = open(FileName.c_str(), fileflags, AccessMode);
+
+   this->FileName = FileName;
+   if (iFd == -1 || OpenInternDescriptor(OpenMode, compressor) == false)
+   {
+      if (iFd != -1)
+      {
+	 close (iFd);
+	 iFd = -1;
+      }
+      return FileFdErrno("open",_("Could not open file %s"), FileName.c_str());
+   }
+
+   SetCloseExec(iFd,true);
+   return true;
+}
+									/*}}}*/
+// FileFd::OpenDescriptor - Open a filedescriptor			/*{{{*/
+bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, CompressMode Compress, bool AutoClose)
+{
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   std::string name;
+
+   // compat with the old API
+   if (Mode == ReadOnlyGzip && Compress == None)
+      Compress = Gzip;
+
+   switch (Compress)
+   {
+   case None: name = "."; break;
+   case Gzip: name = "gzip"; break;
+   case Bzip2: name = "bzip2"; break;
+   case Lzma: name = "lzma"; break;
+   case Xz: name = "xz"; break;
+   case Lz4: name = "lz4"; break;
+   case Zstd: name = "zstd"; break;
+   case Auto:
+   case Extension:
+      if (AutoClose == true && Fd != -1)
+	 close(Fd);
+      return FileFdError("Opening Fd %d in Auto or Extension compression mode is not supported", Fd);
+   }
+   for (; compressor != compressors.end(); ++compressor)
+      if (compressor->Name == name)
+	 break;
+   if (compressor == compressors.end())
+   {
+      if (AutoClose == true && Fd != -1)
+	 close(Fd);
+      return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
+   }
+   return OpenDescriptor(Fd, Mode, *compressor, AutoClose);
+}
+bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration::Compressor const &compressor, bool AutoClose)
+{
+   Close();
+   Flags = (AutoClose) ? FileFd::AutoClose : 0;
+   iFd = Fd;
+   this->FileName = "";
+   if (OpenInternDescriptor(Mode, compressor) == false)
+   {
+      if (iFd != -1 && (
+	(Flags & Compressed) == Compressed ||
+	AutoClose == true))
+      {
+	 close (iFd);
+	 iFd = -1;
+      }
+      return FileFdError(_("Could not open file descriptor %d"), Fd);
+   }
+   return true;
+}
+bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor)
+{
+   if (iFd == -1)
+      return false;
+
+   if (d != nullptr)
+      d->InternalClose(FileName);
+
+   if (d == nullptr)
+   {
+      if (false)
+	 /* dummy so that the rest can be 'else if's */;
+#define APT_COMPRESS_INIT(NAME, CONSTRUCTOR) \
+      else if (compressor.Name == NAME) \
+	 d = new CONSTRUCTOR(this)
+#ifdef HAVE_ZLIB
+      APT_COMPRESS_INIT("gzip", GzipFileFdPrivate);
+#endif
+#ifdef HAVE_BZ2
+      APT_COMPRESS_INIT("bzip2", Bz2FileFdPrivate);
+#endif
+#ifdef HAVE_LZMA
+      APT_COMPRESS_INIT("xz", LzmaFileFdPrivate);
+      APT_COMPRESS_INIT("lzma", LzmaFileFdPrivate);
+#endif
+#ifdef HAVE_LZ4
+      APT_COMPRESS_INIT("lz4", Lz4FileFdPrivate);
+#endif
+#ifdef HAVE_ZSTD
+      APT_COMPRESS_INIT("zstd", ZstdFileFdPrivate);
+#endif
+#undef APT_COMPRESS_INIT
+      else if (compressor.Name == "." || compressor.Binary.empty() == true)
+	 d = new DirectFileFdPrivate(this);
+      else
+	 d = new PipedFileFdPrivate(this);
+
+      if (Mode & BufferedWrite)
+	 d = new BufferedWriteFileFdPrivate(d);
+
+      d->set_openmode(Mode);
+      d->set_compressor(compressor);
+      if ((Flags & AutoClose) != AutoClose && d->InternalAlwaysAutoClose())
+      {
+	 // Need to duplicate fd here or gz/bz2 close for cleanup will close the fd as well
+	 int const internFd = dup(iFd);
+	 if (internFd == -1)
+	    return FileFdErrno("OpenInternDescriptor", _("Could not open file descriptor %d"), iFd);
+	 iFd = internFd;
+      }
+   }
+   return d->InternalOpen(iFd, Mode);
+}
+									/*}}}*/
+// FileFd::~File - Closes the file					/*{{{*/
+// ---------------------------------------------------------------------
+/* If the proper modes are selected then we close the Fd and possibly
+   unlink the file on error. */
+FileFd::~FileFd()
+{
+   Close();
+   if (d != NULL)
+      d->InternalClose(FileName);
+   delete d;
+   d = NULL;
+}
+									/*}}}*/
+// FileFd::Read - Read a bit of the file				/*{{{*/
+// ---------------------------------------------------------------------
+/* We are careful to handle interruption by a signal while reading
+   gracefully. */
+bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
+{
+   if (d == nullptr || Failed())
+      return false;
+   ssize_t Res = 1;
+   errno = 0;
+   if (Actual != 0)
+      *Actual = 0;
+   *((char *)To) = '\0';
+   while (Res > 0 && Size > 0)
+   {
+      Res = d->InternalRead(To, Size);
+
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    // trick the while-loop into running again
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return d->InternalReadError();
+      }
+      
+      To = (char *)To + Res;
+      Size -= Res;
+      if (d != NULL)
+	 d->set_seekpos(d->get_seekpos() + Res);
+      if (Actual != 0)
+	 *Actual += Res;
+   }
+   
+   if (Size == 0)
+      return true;
+   
+   // Eof handling
+   if (Actual != 0)
+   {
+      Flags |= HitEof;
+      return true;
+   }
+
+   return FileFdError(_("read, still have %llu to read but none left"), Size);
+}
+bool FileFd::Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual)
+{
+   ssize_t Res = 1;
+   errno = 0;
+   if (Actual != nullptr)
+      *Actual = 0;
+   *static_cast<char *>(To) = '\0';
+   while (Res > 0 && Size > 0)
+   {
+      Res = read(Fd, To, Size);
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return _error->Errno("read", _("Read error"));
+      }
+      To = static_cast<char *>(To) + Res;
+      Size -= Res;
+      if (Actual != 0)
+	 *Actual += Res;
+   }
+   if (Size == 0)
+      return true;
+   if (Actual != nullptr)
+      return true;
+   return _error->Error(_("read, still have %llu to read but none left"), Size);
+}
+									/*}}}*/
+// FileFd::ReadLine - Read a complete line from the file		/*{{{*/
+char* FileFd::ReadLine(char *To, unsigned long long const Size)
+{
+   *To = '\0';
+   if (d == nullptr || Failed())
+      return nullptr;
+   return d->InternalReadLine(To, Size);
+}
+bool FileFd::ReadLine(std::string &To)
+{
+   To.clear();
+   if (d == nullptr || Failed())
+      return false;
+   constexpr size_t buflen = 4096;
+   char buffer[buflen];
+   size_t len;
+   do
+   {
+      if (d->InternalReadLine(buffer, buflen) == nullptr)
+	 return false;
+      len = strlen(buffer);
+      To.append(buffer, len);
+   } while (len == buflen - 1 && buffer[len - 2] != '\n');
+   // remove the newline at the end
+   auto const i = To.find_last_not_of("\r\n");
+   if (i == std::string::npos)
+      To.clear();
+   else
+      To.erase(i + 1);
+   return true;
+}
+									/*}}}*/
+// FileFd::Flush - Flush the file  					/*{{{*/
+bool FileFd::Flush()
+{
+   if (Failed())
+      return false;
+   if (d == nullptr)
+      return true;
+
+   return d->InternalFlush();
+}
+									/*}}}*/
+// FileFd::Write - Write to the file					/*{{{*/
+bool FileFd::Write(const void *From,unsigned long long Size)
+{
+   if (d == nullptr || Failed())
+      return false;
+   ssize_t Res = 1;
+   errno = 0;
+   while (Res > 0 && Size > 0)
+   {
+      Res = d->InternalWrite(From, Size);
+
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    // trick the while-loop into running again
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return d->InternalWriteError();
+      }
+
+      From = (char const *)From + Res;
+      Size -= Res;
+      if (d != NULL)
+	 d->set_seekpos(d->get_seekpos() + Res);
+   }
+
+   if (Size == 0)
+      return true;
+
+   return FileFdError(_("write, still have %llu to write but couldn't"), Size);
+}
+bool FileFd::Write(int Fd, const void *From, unsigned long long Size)
+{
+   ssize_t Res = 1;
+   errno = 0;
+   while (Res > 0 && Size > 0)
+   {
+      Res = write(Fd,From,Size);
+      if (Res < 0 && errno == EINTR)
+	 continue;
+      if (Res < 0)
+	 return _error->Errno("write",_("Write error"));
+
+      From = (char const *)From + Res;
+      Size -= Res;
+   }
+
+   if (Size == 0)
+      return true;
+
+   return _error->Error(_("write, still have %llu to write but couldn't"), Size);
+}
+									/*}}}*/
+// FileFd::Seek - Seek in the file					/*{{{*/
+bool FileFd::Seek(unsigned long long To)
+{
+   if (d == nullptr || Failed())
+      return false;
+   Flags &= ~HitEof;
+   return d->InternalSeek(To);
+}
+									/*}}}*/
+// FileFd::Skip - Skip over data in the file				/*{{{*/
+bool FileFd::Skip(unsigned long long Over)
+{
+   if (d == nullptr || Failed())
+      return false;
+   return d->InternalSkip(Over);
+}
+									/*}}}*/
+// FileFd::Truncate - Truncate the file					/*{{{*/
+bool FileFd::Truncate(unsigned long long To)
+{
+   if (d == nullptr || Failed())
+      return false;
+   // truncating /dev/null is always successful - as we get an error otherwise
+   if (To == 0 && FileName == "/dev/null")
+      return true;
+   return d->InternalTruncate(To);
+}
+									/*}}}*/
+// FileFd::Tell - Current seek position					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned long long FileFd::Tell()
+{
+   if (d == nullptr || Failed())
+      return false;
+   off_t const Res = d->InternalTell();
+   if (Res == (off_t)-1)
+      FileFdErrno("lseek","Failed to determine the current file position");
+   d->set_seekpos(Res);
+   return Res;
+}
+									/*}}}*/
+static bool StatFileFd(char const * const msg, int const iFd, std::string const &FileName, struct stat &Buf, FileFdPrivate * const d) /*{{{*/
+{
+   bool ispipe = (d != NULL && d->get_is_pipe() == true);
+   if (ispipe == false)
+   {
+      if (fstat(iFd,&Buf) != 0)
+	 // higher-level code will generate more meaningful messages,
+	 // even translated this would be meaningless for users
+	 return _error->Errno("fstat", "Unable to determine %s for fd %i", msg, iFd);
+      if (FileName.empty() == false)
+	 ispipe = S_ISFIFO(Buf.st_mode);
+   }
+
+   // for compressor pipes st_size is undefined and at 'best' zero
+   if (ispipe == true)
+   {
+      // we set it here, too, as we get the info here for free
+      // in theory the Open-methods should take care of it already
+      if (d != NULL)
+	 d->set_is_pipe(true);
+      if (stat(FileName.c_str(), &Buf) != 0)
+	 return _error->Errno("fstat", "Unable to determine %s for file %s", msg, FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// FileFd::FileSize - Return the size of the file			/*{{{*/
+unsigned long long FileFd::FileSize()
+{
+   struct stat Buf;
+   if (StatFileFd("file size", iFd, FileName, Buf, d) == false)
+   {
+      Flags |= Fail;
+      return 0;
+   }
+   return Buf.st_size;
+}
+									/*}}}*/
+// FileFd::ModificationTime - Return the time of last touch		/*{{{*/
+time_t FileFd::ModificationTime()
+{
+   struct stat Buf;
+   if (StatFileFd("modification time", iFd, FileName, Buf, d) == false)
+   {
+      Flags |= Fail;
+      return 0;
+   }
+   return Buf.st_mtime;
+}
+									/*}}}*/
+// FileFd::Size - Return the size of the content in the file		/*{{{*/
+unsigned long long FileFd::Size()
+{
+   if (d == nullptr)
+      return 0;
+   return d->InternalSize();
+}
+									/*}}}*/
+// FileFd::Close - Close the file if the close flag is set		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FileFd::Close()
+{
+   if (Failed() == false && Flush() == false)
+      return false;
+   if (iFd == -1)
+      return true;
+
+   bool Res = true;
+   if ((Flags & AutoClose) == AutoClose)
+   {
+      if ((Flags & Compressed) != Compressed && iFd > 0 && close(iFd) != 0)
+	 Res &= _error->Errno("close",_("Problem closing the file %s"), FileName.c_str());
+   }
+
+   if (d != NULL)
+   {
+      Res &= d->InternalClose(FileName);
+      delete d;
+      d = NULL;
+   }
+
+   if ((Flags & Replace) == Replace) {
+      if (Failed() == false && rename(TemporaryFileName.c_str(), FileName.c_str()) != 0)
+	 Res &= _error->Errno("rename",_("Problem renaming the file %s to %s"), TemporaryFileName.c_str(), FileName.c_str());
+
+      FileName = TemporaryFileName; // for the unlink() below.
+      TemporaryFileName.clear();
+   }
+
+   iFd = -1;
+
+   if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
+       FileName.empty() == false)
+      Res &= RemoveFile("FileFd::Close", FileName);
+
+   if (Res == false)
+      Flags |= Fail;
+   return Res;
+}
+									/*}}}*/
+// FileFd::Sync - Sync the file						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FileFd::Sync()
+{
+   if (fsync(iFd) != 0)
+      return FileFdErrno("sync",_("Problem syncing the file"));
+   return true;
+}
+									/*}}}*/
+// FileFd::FileFdErrno - set Fail and call _error->Errno		*{{{*/
+bool FileFd::FileFdErrno(const char *Function, const char *Description,...)
+{
+   Flags |= Fail;
+   va_list args;
+   size_t msgSize = 400;
+   int const errsv = errno;
+   bool retry;
+   do {
+      va_start(args,Description);
+      retry = _error->InsertErrno(GlobalError::ERROR, Function, Description, args, errsv, msgSize);
+      va_end(args);
+   } while (retry);
+   return false;
+}
+									/*}}}*/
+// FileFd::FileFdError - set Fail and call _error->Error		*{{{*/
+bool FileFd::FileFdError(const char *Description,...) {
+   Flags |= Fail;
+   va_list args;
+   size_t msgSize = 400;
+   bool retry;
+   do {
+      va_start(args,Description);
+      retry = _error->Insert(GlobalError::ERROR, Description, args, msgSize);
+      va_end(args);
+   } while (retry);
+   return false;
+}
+									/*}}}*/
+// Glob - wrapper around "glob()"					/*{{{*/
+std::vector<std::string> Glob(std::string const &pattern, int flags)
+{
+   std::vector<std::string> result;
+   glob_t globbuf;
+   int glob_res;
+   unsigned int i;
+
+   glob_res = glob(pattern.c_str(),  flags, NULL, &globbuf);
+
+   if (glob_res != 0)
+   {
+      if(glob_res != GLOB_NOMATCH) {
+         _error->Errno("glob", "Problem with glob");
+         return result;
+      }
+   }
+
+   // append results
+   for(i=0;i<globbuf.gl_pathc;i++)
+      result.push_back(string(globbuf.gl_pathv[i]));
+
+   globfree(&globbuf);
+   return result;
+}
+									/*}}}*/
+static std::string APT_NONNULL(1) GetTempDirEnv(char const * const env)	/*{{{*/
+{
+   const char *tmpdir = getenv(env);
+
+#ifdef P_tmpdir
+   if (!tmpdir)
+      tmpdir = P_tmpdir;
+#endif
+
+   struct stat st;
+   if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set
+	 stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0) // exists and is directory
+      tmpdir = "/tmp";
+   else if (geteuid() != 0 && // root can do everything anyway
+	 faccessat(AT_FDCWD, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS) != 0) // current user has rwx access to directory
+      tmpdir = "/tmp";
+
+   return string(tmpdir);
+}
+									/*}}}*/
+std::string GetTempDir()						/*{{{*/
+{
+   return GetTempDirEnv("TMPDIR");
+}
+std::string GetTempDir(std::string const &User)
+{
+   // no need/possibility to drop privs
+   if(getuid() != 0 || User.empty() || User == "root")
+      return GetTempDir();
+
+   struct passwd const * const pw = getpwnam(User.c_str());
+   if (pw == NULL)
+      return GetTempDir();
+
+   gid_t const old_euid = geteuid();
+   gid_t const old_egid = getegid();
+   if (setegid(pw->pw_gid) != 0)
+      _error->Errno("setegid", "setegid %u failed", pw->pw_gid);
+   if (seteuid(pw->pw_uid) != 0)
+      _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid);
+
+   std::string const tmp = GetTempDir();
+
+   if (seteuid(old_euid) != 0)
+      _error->Errno("seteuid", "seteuid %u failed", old_euid);
+   if (setegid(old_egid) != 0)
+      _error->Errno("setegid", "setegid %u failed", old_egid);
+
+   return tmp;
+}
+									/*}}}*/
+FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd)	/*{{{*/
+{
+   return GetTempFile(Prefix, ImmediateUnlink, TmpFd, false);
+}
+FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd, bool Buffered)
+{
+   std::string fn;
+   std::string const tempdir = GetTempDir();
+   int fd = -1;
+#ifdef O_TMPFILE
+   if (ImmediateUnlink)
+      fd = open(tempdir.c_str(), O_RDWR|O_TMPFILE|O_EXCL|O_CLOEXEC, 0600);
+   if (fd < 0)
+#endif
+   {
+      auto const suffix = Prefix.find(".XXXXXX.");
+      std::vector<char> buffer(tempdir.length() + 1 + Prefix.length() + (suffix == std::string::npos ? 7 : 0) + 1, '\0');
+      if (suffix != std::string::npos)
+      {
+	 if (snprintf(buffer.data(), buffer.size(), "%s/%s", tempdir.c_str(), Prefix.c_str()) > 0)
+	 {
+	    ssize_t const suffixlen = (buffer.size() - 1) - (tempdir.length() + 1 + suffix + 7);
+	    if (likely(suffixlen > 0))
+	       fd = mkstemps(buffer.data(), suffixlen);
+	 }
+      }
+      else
+      {
+	 if (snprintf(buffer.data(), buffer.size(), "%s/%s.XXXXXX", tempdir.c_str(), Prefix.c_str()) > 0)
+	    fd = mkstemp(buffer.data());
+      }
+      fn.assign(buffer.data(), buffer.size() - 1);
+      if (ImmediateUnlink && fd != -1)
+	 unlink(fn.c_str());
+   }
+   if (fd < 0)
+   {
+      _error->Errno("GetTempFile",_("Unable to mkstemp %s"), fn.c_str());
+      return nullptr;
+   }
+   FileFd * const Fd = TmpFd == nullptr ? new FileFd() : TmpFd;
+   if (not Fd->OpenDescriptor(fd, FileFd::ReadWrite | (Buffered ? FileFd::BufferedWrite : 0), FileFd::None, true))
+   {
+      _error->Errno("GetTempFile",_("Unable to write to %s"),fn.c_str());
+      if (TmpFd == nullptr)
+	 delete Fd;
+      return nullptr;
+   }
+   if (not ImmediateUnlink)
+      Fd->SetFileName(fn);
+   return Fd;
+}
+									/*}}}*/
+bool Rename(std::string From, std::string To)				/*{{{*/
+{
+   if (rename(From.c_str(),To.c_str()) != 0)
+   {
+      _error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
+                    From.c_str(),To.c_str());
+      return false;
+   }
+   return true;
+}
+									/*}}}*/
+bool Popen(const char *Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode, bool CaptureStderr, bool Sandbox) /*{{{*/
+{
+   int fd;
+   if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)
+      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
+
+   int Pipe[2] = {-1, -1};
+   if(pipe(Pipe) != 0)
+      return _error->Errno("pipe", _("Failed to create subprocess IPC"));
+
+   std::set<int> keep_fds;
+   keep_fds.insert(Pipe[0]);
+   keep_fds.insert(Pipe[1]);
+   Child = ExecFork(keep_fds);
+   if(Child < 0)
+      return _error->Errno("fork", "Failed to fork");
+   if(Child == 0)
+   {
+      if (Sandbox && (getuid() == 0 || geteuid() == 0) && !DropPrivileges())
+      {
+	 _error->DumpErrors();
+	 _exit(1);
+      }
+      if(Mode == FileFd::ReadOnly)
+      {
+         close(Pipe[0]);
+         fd = Pipe[1];
+      }
+      else if(Mode == FileFd::WriteOnly)
+      {
+         close(Pipe[1]);
+         fd = Pipe[0];
+      }
+
+      if(Mode == FileFd::ReadOnly)
+      {
+         dup2(fd, 1);
+	 if (CaptureStderr == true)
+	    dup2(fd, 2);
+      } else if(Mode == FileFd::WriteOnly)
+         dup2(fd, 0);
+
+      execv(Args[0], (char**)Args);
+      _exit(100);
+   }
+   if(Mode == FileFd::ReadOnly)
+   {
+      close(Pipe[1]);
+      fd = Pipe[0];
+   }
+   else if(Mode == FileFd::WriteOnly)
+   {
+      close(Pipe[0]);
+      fd = Pipe[1];
+   }
+   else
+      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
+   Fd.OpenDescriptor(fd, Mode, FileFd::None, true);
+
+   return true;
+}
+									/*}}}*/
+bool DropPrivileges()							/*{{{*/
+{
+   if(_config->FindB("Debug::NoDropPrivs", false) == true)
+      return true;
+
+#if __gnu_linux__
+#if defined(PR_SET_NO_NEW_PRIVS) && ( PR_SET_NO_NEW_PRIVS != 38 )
+#error "PR_SET_NO_NEW_PRIVS is defined, but with a different value than expected!"
+#endif
+   // see prctl(2), needs linux3.5 at runtime - magic constant to avoid it at buildtime
+   int ret = prctl(38, 1, 0, 0, 0);
+   // ignore EINVAL - kernel is too old to understand the option
+   if(ret < 0 && errno != EINVAL)
+      _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
+#endif
+
+   // empty setting disables privilege dropping - this also ensures
+   // backward compatibility, see bug #764506
+   const std::string toUser = _config->Find("APT::Sandbox::User");
+   if (toUser.empty() || toUser == "root")
+      return true;
+
+   // a lot can go wrong trying to drop privileges completely,
+   // so ideally we would like to verify that we have done it –
+   // but the verify asks for too much in case of fakeroot (and alike)
+   // [Specific checks can be overridden with dedicated options]
+   bool const VerifySandboxing = _config->FindB("APT::Sandbox::Verify", false);
+
+   // uid will be 0 in the end, but gid might be different anyway
+   uid_t const old_uid = getuid();
+   gid_t const old_gid = getgid();
+
+   if (old_uid != 0)
+      return true;
+
+   struct passwd *pw = getpwnam(toUser.c_str());
+   if (pw == NULL)
+      return _error->Error("No user %s, can not drop rights", toUser.c_str());
+
+   // Do not change the order here, it might break things
+   // Get rid of all our supplementary groups first
+   if (setgroups(1, &pw->pw_gid))
+      return _error->Errno("setgroups", "Failed to setgroups");
+
+   // Now change the group ids to the new user
+#ifdef HAVE_SETRESGID
+   if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
+      return _error->Errno("setresgid", "Failed to set new group ids");
+#else
+   if (setegid(pw->pw_gid) != 0)
+      return _error->Errno("setegid", "Failed to setegid");
+
+   if (setgid(pw->pw_gid) != 0)
+      return _error->Errno("setgid", "Failed to setgid");
+#endif
+
+   // Change the user ids to the new user
+#ifdef HAVE_SETRESUID
+   if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
+      return _error->Errno("setresuid", "Failed to set new user ids");
+#else
+   if (setuid(pw->pw_uid) != 0)
+      return _error->Errno("setuid", "Failed to setuid");
+   if (seteuid(pw->pw_uid) != 0)
+      return _error->Errno("seteuid", "Failed to seteuid");
+#endif
+
+   // disabled by default as fakeroot doesn't implement getgroups currently (#806521)
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Groups", false) == true)
+   {
+      // Verify that the user isn't still in any supplementary groups
+      long const ngroups_max = sysconf(_SC_NGROUPS_MAX);
+      std::unique_ptr<gid_t[]> gidlist(new gid_t[ngroups_max]);
+      if (unlikely(gidlist == NULL))
+	 return _error->Error("Allocation of a list of size %lu for getgroups failed", ngroups_max);
+      ssize_t gidlist_nr;
+      if ((gidlist_nr = getgroups(ngroups_max, gidlist.get())) < 0)
+	 return _error->Errno("getgroups", "Could not get new groups (%lu)", ngroups_max);
+      for (ssize_t i = 0; i < gidlist_nr; ++i)
+	 if (gidlist[i] != pw->pw_gid)
+	    return _error->Error("Could not switch group, user %s is still in group %d", toUser.c_str(), gidlist[i]);
+   }
+
+   // enabled by default as all fakeroot-lookalikes should fake that accordingly
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::IDs", true) == true)
+   {
+      // Verify that gid, egid, uid, and euid changed
+      if (getgid() != pw->pw_gid)
+	 return _error->Error("Could not switch group");
+      if (getegid() != pw->pw_gid)
+	 return _error->Error("Could not switch effective group");
+      if (getuid() != pw->pw_uid)
+	 return _error->Error("Could not switch user");
+      if (geteuid() != pw->pw_uid)
+	 return _error->Error("Could not switch effective user");
+
+#ifdef HAVE_GETRESUID
+      // verify that the saved set-user-id was changed as well
+      uid_t ruid = 0;
+      uid_t euid = 0;
+      uid_t suid = 0;
+      if (getresuid(&ruid, &euid, &suid))
+	 return _error->Errno("getresuid", "Could not get saved set-user-ID");
+      if (suid != pw->pw_uid)
+	 return _error->Error("Could not switch saved set-user-ID");
+#endif
+
+#ifdef HAVE_GETRESGID
+      // verify that the saved set-group-id was changed as well
+      gid_t rgid = 0;
+      gid_t egid = 0;
+      gid_t sgid = 0;
+      if (getresgid(&rgid, &egid, &sgid))
+	 return _error->Errno("getresuid", "Could not get saved set-group-ID");
+      if (sgid != pw->pw_gid)
+	 return _error->Error("Could not switch saved set-group-ID");
+#endif
+   }
+
+   // disabled as fakeroot doesn't forbid (by design) (re)gaining root from unprivileged
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Regain", false) == true)
+   {
+      // Check that uid and gid changes do not work anymore
+      if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1))
+	 return _error->Error("Could restore a gid to root, privilege dropping did not work");
+
+      if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
+	 return _error->Error("Could restore a uid to root, privilege dropping did not work");
+   }
+
+   if (_config->FindB("APT::Sandbox::ResetEnvironment", true))
+   {
+      setenv("HOME", pw->pw_dir, 1);
+      setenv("USER", pw->pw_name, 1);
+      setenv("USERNAME", pw->pw_name, 1);
+      setenv("LOGNAME", pw->pw_name, 1);
+      auto const shell = flNotDir(pw->pw_shell);
+      if (shell == "false" || shell == "nologin")
+	 setenv("SHELL", "/bin/sh", 1);
+      else
+	 setenv("SHELL", pw->pw_shell, 1);
+      auto const apt_setenv_tmp = [](char const * const env) {
+	 auto const tmpdir = getenv(env);
+	 if (tmpdir != nullptr)
+	 {
+	    auto const ourtmpdir = GetTempDirEnv(env);
+	    if (ourtmpdir != tmpdir)
+	       setenv(env, ourtmpdir.c_str(), 1);
+	 }
+      };
+      apt_setenv_tmp("TMPDIR");
+      apt_setenv_tmp("TEMPDIR");
+      apt_setenv_tmp("TMP");
+      apt_setenv_tmp("TEMP");
+   }
+
+   return true;
+}
+									/*}}}*/
+bool OpenConfigurationFileFd(std::string const &File, FileFd &Fd) /*{{{*/
+{
+   int const fd = open(File.c_str(), O_RDONLY | O_CLOEXEC | O_NOCTTY);
+   if (fd == -1)
+      return _error->WarningE("open", _("Unable to read %s"), File.c_str());
+   APT::Configuration::Compressor none(".", "", "", nullptr, nullptr, 0);
+   if (Fd.OpenDescriptor(fd, FileFd::ReadOnly, none, true) == false)
+      return false;
+   Fd.SetFileName(File);
+   return true;
+}
+									/*}}}*/
+int Inhibit(const char *what, const char *who, const char *why, const char *mode) /*{{{*/
+{
+#ifdef HAVE_SYSTEMD
+   sd_bus_error error = SD_BUS_ERROR_NULL;
+   sd_bus_message *m = NULL;
+   sd_bus *bus = NULL;
+   int fd;
+   int r;
+
+   r = sd_bus_open_system(&bus);
+   if (r < 0)
+      goto out;
+
+   r = sd_bus_call_method(bus,
+			  "org.freedesktop.login1",
+			  "/org/freedesktop/login1",
+			  "org.freedesktop.login1.Manager",
+			  "Inhibit",
+			  &error,
+			  &m,
+			  "ssss",
+			  what,
+			  who,
+			  why,
+			  mode);
+   if (r < 0)
+      goto out;
+
+   r = sd_bus_message_read(m, "h", &fd);
+   if (r < 0)
+      goto out;
+
+   // We received a file descriptor, return it - systemd will close the read fd
+   // on free, so let's duplicate it here.
+   r = dup(fd);
+out:
+   sd_bus_error_free(&error);
+   sd_bus_message_unref(m);
+   sd_bus_unref(bus);
+   return r;
+#else
+   return -ENOTSUP;
+#endif
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/fileutl.h b/apt-pkg/contrib/fileutl.h
new file mode 100644
index 0000000..970b118
--- /dev/null
+++ b/apt-pkg/contrib/fileutl.h
@@ -0,0 +1,287 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   File Utilities
+   
+   CopyFile - Buffered copy of a single file
+   GetLock - dpkg compatible lock file manipulation (fcntl)
+   FileExists - Returns true if the file exists
+   SafeGetCWD - Returns the CWD in a string with overrun protection 
+   
+   The file class is a handy abstraction for various functions+classes
+   that need to accept filenames.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_FILEUTL_H
+#define PKGLIB_FILEUTL_H
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/macros.h>
+
+#include <set>
+#include <string>
+#include <vector>
+#include <sys/stat.h>
+#include <time.h>
+
+/* Define this for python-apt */
+#define APT_HAS_GZIP 1
+
+class FileFdPrivate;
+class APT_PUBLIC FileFd
+{
+   friend class FileFdPrivate;
+   friend class GzipFileFdPrivate;
+   friend class Bz2FileFdPrivate;
+   friend class LzmaFileFdPrivate;
+   friend class Lz4FileFdPrivate;
+   friend class ZstdFileFdPrivate;
+   friend class DirectFileFdPrivate;
+   friend class PipedFileFdPrivate;
+   protected:
+   int iFd;
+ 
+   enum LocalFlags {AutoClose = (1<<0),Fail = (1<<1),DelOnFail = (1<<2),
+                    HitEof = (1<<3), Replace = (1<<4), Compressed = (1<<5) };
+   unsigned long Flags;
+   std::string FileName;
+   std::string TemporaryFileName;
+
+   public:
+   enum OpenMode {
+	ReadOnly = (1 << 0),
+	WriteOnly = (1 << 1),
+	ReadWrite = ReadOnly | WriteOnly,
+
+	Create = (1 << 2),
+	Exclusive = (1 << 3),
+	Atomic = Exclusive | (1 << 4),
+	Empty = (1 << 5),
+	BufferedWrite = (1 << 6),
+
+	WriteEmpty = ReadWrite | Create | Empty,
+	WriteExists = ReadWrite,
+	WriteAny = ReadWrite | Create,
+	WriteTemp = ReadWrite | Create | Exclusive,
+	ReadOnlyGzip,
+	WriteAtomic = ReadWrite | Create | Atomic
+   };
+   enum CompressMode
+   {
+      Auto = 'A',
+      None = 'N',
+      Extension = 'E',
+      Gzip = 'G',
+      Bzip2 = 'B',
+      Lzma = 'L',
+      Xz = 'X',
+      Lz4 = '4',
+      Zstd = 'Z'
+   };
+
+   inline bool Read(void *To,unsigned long long Size,bool AllowEof)
+   {
+      unsigned long long Jnk;
+      if (AllowEof)
+	 return Read(To,Size,&Jnk);
+      return Read(To,Size);
+   }   
+   bool Read(void *To,unsigned long long Size,unsigned long long *Actual = 0);
+   bool static Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual = 0);
+   /** read a complete line or until buffer is full
+    *
+    * The buffer will always be \\0 terminated, so at most Size-1 characters are read.
+    * If the buffer holds a complete line the last character (before \\0) will be
+    * the newline character \\n otherwise the line was longer than the buffer.
+    *
+    * @param To buffer which will hold the line
+    * @param Size of the buffer to fill
+    * @param \b nullptr is returned in error cases, otherwise
+    * the parameter \b To now filled with the line.
+    */
+   char* ReadLine(char *To, unsigned long long const Size);
+   /** read a complete line from the file
+    *
+    *  Similar to std::getline() the string does \b not include
+    *  the newline, but just the content of the line as the newline
+    *  is not needed to distinguish cases as for the other #ReadLine method.
+    *
+    *  @param To string which will hold the line
+    *  @return \b true if successful, otherwise \b false
+    */
+   bool ReadLine(std::string &To);
+   bool Flush();
+   bool Write(const void *From,unsigned long long Size);
+   bool static Write(int Fd, const void *From, unsigned long long Size);
+   bool Seek(unsigned long long To);
+   bool Skip(unsigned long long To);
+   bool Truncate(unsigned long long To);
+   unsigned long long Tell();
+   // the size of the file content (compressed files will be uncompressed first)
+   unsigned long long Size();
+   // the size of the file itself
+   unsigned long long FileSize();
+   time_t ModificationTime();
+
+   bool Open(std::string FileName,unsigned int const Mode,CompressMode Compress,unsigned long const AccessMode = 0666);
+   bool Open(std::string FileName,unsigned int const Mode,APT::Configuration::Compressor const &compressor,unsigned long const AccessMode = 0666);
+   inline bool Open(std::string const &FileName,unsigned int const Mode, unsigned long const AccessMode = 0666) {
+      return Open(FileName, Mode, None, AccessMode);
+   };
+   bool OpenDescriptor(int Fd, unsigned int const Mode, CompressMode Compress, bool AutoClose=false);
+   bool OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration::Compressor const &compressor, bool AutoClose=false);
+   inline bool OpenDescriptor(int Fd, unsigned int const Mode, bool AutoClose=false) {
+      return OpenDescriptor(Fd, Mode, None, AutoClose);
+   };
+   bool Close();
+   bool Sync();
+   
+   // Simple manipulators
+   inline int Fd() {return iFd;};
+   inline void Fd(int fd) { OpenDescriptor(fd, ReadWrite);};
+
+   inline bool IsOpen() {return iFd >= 0;};
+   inline bool Failed() {return (Flags & Fail) == Fail;};
+   inline void EraseOnFailure() {Flags |= DelOnFail;};
+   inline void OpFail() {Flags |= Fail;};
+   inline bool Eof() {return (Flags & HitEof) == HitEof;};
+   inline bool IsCompressed() {return (Flags & Compressed) == Compressed;};
+   inline std::string &Name() {return FileName;};
+   inline void SetFileName(std::string const &name) { FileName = name; };
+
+   FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode = 0666);
+   FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode = 0666);
+   FileFd();
+   FileFd(int const Fd, unsigned int const Mode = ReadWrite, CompressMode Compress = None);
+   FileFd(int const Fd, bool const AutoClose);
+   virtual ~FileFd();
+
+   private:
+   FileFdPrivate * d;
+   APT_HIDDEN FileFd(const FileFd &);
+   APT_HIDDEN FileFd & operator=(const FileFd &);
+   APT_HIDDEN bool OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor);
+
+   // private helpers to set Fail flag and call _error->Error
+   APT_HIDDEN bool FileFdErrno(const char* Function, const char* Description,...) APT_PRINTF(3) APT_COLD;
+   APT_HIDDEN bool FileFdError(const char* Description,...) APT_PRINTF(2) APT_COLD;
+};
+
+APT_PUBLIC bool RunScripts(const char *Cnf);
+APT_PUBLIC bool CopyFile(FileFd &From,FileFd &To);
+APT_PUBLIC bool RemoveFile(char const * const Function, std::string const &FileName);
+APT_PUBLIC bool RemoveFileAt(char const * const Function, int const dirfd, std::string const &FileName);
+APT_PUBLIC int GetLock(std::string File,bool Errors = true);
+APT_PUBLIC bool FileExists(std::string File);
+APT_PUBLIC bool RealFileExists(std::string File);
+APT_PUBLIC bool DirectoryExists(std::string const &Path);
+APT_PUBLIC bool CreateDirectory(std::string const &Parent, std::string const &Path);
+APT_PUBLIC time_t GetModificationTime(std::string const &Path);
+APT_PUBLIC bool Rename(std::string From, std::string To);
+
+APT_PUBLIC std::string GetTempDir();
+APT_PUBLIC std::string GetTempDir(std::string const &User);
+APT_PUBLIC FileFd* GetTempFile(std::string const &Prefix = "",
+                    bool ImmediateUnlink = true,
+		    FileFd * const TmpFd = NULL);
+
+// FIXME: GetTempFile should always return a buffered file
+APT_HIDDEN FileFd* GetTempFile(std::string const &Prefix,
+                    bool ImmediateUnlink ,
+		    FileFd * const TmpFd,
+          bool Buffered);
+
+/** \brief Ensure the existence of the given Path
+ *
+ *  \param Parent directory of the Path directory - a trailing
+ *  /apt/ will be removed before CreateDirectory call.
+ *  \param Path which should exist after (successful) call
+ */
+APT_PUBLIC bool CreateAPTDirectoryIfNeeded(std::string const &Parent, std::string const &Path);
+
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, std::string const &Ext,
+					bool const &SortList, bool const &AllowNoExt=false);
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, std::vector<std::string> const &Ext,
+					bool const &SortList);
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, bool SortList);
+APT_PUBLIC std::string SafeGetCWD();
+APT_PUBLIC void SetCloseExec(int Fd,bool Close);
+APT_PUBLIC void SetNonBlock(int Fd,bool Block);
+APT_PUBLIC bool WaitFd(int Fd,bool write = false,unsigned long timeout = 0);
+APT_PUBLIC pid_t ExecFork();
+APT_PUBLIC pid_t ExecFork(std::set<int> keep_fds);
+APT_PUBLIC void MergeKeepFdsFromConfiguration(std::set<int> &keep_fds);
+APT_PUBLIC bool ExecWait(pid_t Pid,const char *Name,bool Reap = false);
+
+// check if the given file starts with a PGP cleartext signature
+APT_PUBLIC bool StartsWithGPGClearTextSignature(std::string const &FileName);
+
+/** change file attributes to requested known good values
+ *
+ * The method skips the user:group setting if not root.
+ *
+ * @param requester is printed as functionname in error cases
+ * @param file is the file to be modified
+ * @param user is the (new) owner of the file, e.g. _apt
+ * @param group is the (new) group owning the file, e.g. root
+ * @param mode is the access mode of the file, e.g. 0644
+ */
+APT_PUBLIC bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode);
+
+/**
+ * \brief Drop privileges
+ *
+ * Drop the privileges to the user _apt (or the one specified in
+ * APT::Sandbox::User). This does not set the supplementary group
+ * ids up correctly, it only uses the default group. Also prevent
+ * the process from gaining any new privileges afterwards, at least
+ * on Linux.
+ *
+ * \return true on success, false on failure with _error set
+ */
+APT_PUBLIC bool DropPrivileges();
+
+// File string manipulators
+APT_PUBLIC std::string flNotDir(std::string File);
+APT_PUBLIC std::string flNotFile(std::string File);
+APT_PUBLIC std::string flNoLink(std::string File);
+APT_PUBLIC std::string flExtension(std::string File);
+APT_PUBLIC std::string flCombine(std::string Dir,std::string File);
+
+/** \brief Takes a file path and returns the absolute path
+ */
+APT_PUBLIC std::string flAbsPath(std::string File);
+/** \brief removes superfluous /./ and // from path */
+APT_HIDDEN std::string flNormalize(std::string file);
+
+// simple c++ glob
+APT_PUBLIC std::vector<std::string> Glob(std::string const &pattern, int flags=0);
+
+/** \brief Popen() implementation that execv() instead of using a shell
+ *
+ * \param Args the execv style command to run
+ * \param FileFd is a reference to the FileFd to use for input or output
+ * \param Child a reference to the integer that stores the child pid
+ *        Note that you must call ExecWait() or similar to cleanup
+ * \param Mode is either FileFd::ReadOnly or FileFd::WriteOnly
+ * \param CaptureStderr True if we should capture stderr in addition to stdout.
+ *                      (default: True).
+ * \param Sandbox True if this should run sandboxed
+ * \return true on success, false on failure with _error set
+ */
+APT_PUBLIC bool Popen(const char *Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode, bool CaptureStderr = true, bool Sandbox = false);
+
+APT_HIDDEN bool OpenConfigurationFileFd(std::string const &File, FileFd &Fd);
+
+APT_HIDDEN int Inhibit(const char *what, const char *who, const char *why, const char *mode);
+
+#endif
diff --git a/apt-pkg/contrib/gpgv.cc b/apt-pkg/contrib/gpgv.cc
new file mode 100644
index 0000000..3368ece
--- /dev/null
+++ b/apt-pkg/contrib/gpgv.cc
@@ -0,0 +1,568 @@
+// -*- mode: cpp; mode: fold -*-
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/strutl.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// syntactic sugar to wrap a raw pointer with a custom deleter in a std::unique_ptr
+static std::unique_ptr<char, decltype(&free)> make_unique_char(void *const str = nullptr)
+{
+   return {static_cast<char *>(str), &free};
+}
+static std::unique_ptr<FILE, decltype(&fclose)> make_unique_FILE(std::string const &filename, char const *const mode)
+{
+   return {fopen(filename.c_str(), mode), &fclose};
+}
+
+class LineBuffer							/*{{{*/
+{
+   char *buffer = nullptr;
+   size_t buffer_size = 0;
+   int line_length = 0;
+   // a "normal" find_last_not_of returns npos if not found
+   int find_last_not_of_length(APT::StringView const bad) const
+   {
+      for (int result = line_length - 1; result >= 0; --result)
+	 if (bad.find(buffer[result]) == APT::StringView::npos)
+	    return result + 1;
+      return 0;
+   }
+
+   public:
+   bool empty() const noexcept { return view().empty(); }
+   APT::StringView view() const noexcept { return {buffer, static_cast<size_t>(line_length)}; }
+   bool starts_with(APT::StringView const start) const { return view().substr(0, start.size()) == start; }
+
+   bool writeTo(FileFd *const to, size_t offset = 0) const
+   {
+      if (to == nullptr)
+	 return true;
+      return to->Write(buffer + offset, line_length - offset);
+   }
+   bool writeLineTo(FileFd *const to) const
+    {
+       if (to == nullptr)
+         return true;
+       buffer[line_length] = '\n';
+       bool const result = to->Write(buffer, line_length + 1);
+       buffer[line_length] = '\0';
+       return result;
+    }
+   bool writeNewLineIf(FileFd *const to, bool const condition) const
+   {
+      if (not condition || to == nullptr)
+	 return true;
+      return to->Write("\n", 1);
+   }
+
+   bool readFrom(FILE *stream, std::string const &InFile, bool acceptEoF = false)
+   {
+      errno = 0;
+      line_length = getline(&buffer, &buffer_size, stream);
+      if (errno != 0)
+	 return _error->Errno("getline", "Could not read from %s", InFile.c_str());
+      if (line_length == -1)
+      {
+	 if (acceptEoF)
+	    return false;
+	 return _error->Error("Splitting of clearsigned file %s failed as it doesn't contain all expected parts", InFile.c_str());
+      }
+      // a) remove newline characters, so we can work consistently with lines
+      line_length = find_last_not_of_length("\n\r");
+      // b) remove trailing whitespaces as defined by rfc4880 §7.1
+      line_length = find_last_not_of_length(" \t");
+      buffer[line_length] = '\0';
+      return true;
+   }
+
+   ~LineBuffer() { free(buffer); }
+};
+static bool operator==(LineBuffer const &buf, APT::StringView const exp) noexcept
+{
+   return buf.view() == exp;
+}
+static bool operator!=(LineBuffer const &buf, APT::StringView const exp) noexcept
+{
+   return buf.view() != exp;
+}
+									/*}}}*/
+// ExecGPGV - returns the command needed for verify			/*{{{*/
+// ---------------------------------------------------------------------
+/* Generating the commandline for calling gpg is somehow complicated as
+   we need to add multiple keyrings and user supplied options.
+   Also, as gpg has no options to enforce a certain reduced style of
+   clear-signed files (=the complete content of the file is signed and
+   the content isn't encoded) we do a divide and conquer approach here
+   and split up the clear-signed file in message and signature for gpg.
+   And as a cherry on the cake, we use our apt-key wrapper to do part
+   of the lifting in regards to merging keyrings. Fun for the whole family.
+*/
+static void APT_PRINTF(4) apt_error(std::ostream &outterm, int const statusfd, int fd[2], const char *format, ...)
+{
+   std::ostringstream outstr;
+   std::ostream &out = (statusfd == -1) ? outterm : outstr;
+   va_list args;
+   ssize_t size = 400;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(out, format, args, size);
+      va_end(args);
+      if (ret)
+	 break;
+   }
+   if (statusfd != -1)
+   {
+      auto const errtag = "[APTKEY:] ERROR ";
+      outstr << '\n';
+      auto const errtext = outstr.str();
+      if (not FileFd::Write(fd[1], errtag, strlen(errtag)) ||
+	    not FileFd::Write(fd[1], errtext.data(), errtext.size()))
+	 outterm << errtext << std::flush;
+   }
+}
+void ExecGPGV(std::string const &File, std::string const &FileGPG,
+             int const &statusfd, int fd[2], std::string const &key)
+{
+   #define EINTERNAL 111
+   std::string const aptkey = _config->Find("Dir::Bin::apt-key", CMAKE_INSTALL_FULL_BINDIR "/apt-key");
+
+   bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
+   struct exiter {
+      std::vector<const char *> files;
+      void operator ()(int code) APT_NORETURN {
+	 std::for_each(files.begin(), files.end(), unlink);
+	 exit(code);
+      }
+   } local_exit;
+
+
+   std::vector<const char *> Args;
+   Args.reserve(10);
+
+   Args.push_back(aptkey.c_str());
+   Args.push_back("--quiet");
+   Args.push_back("--readonly");
+   auto const keysFileFpr = VectorizeString(key, ',');
+   for (auto const &k: keysFileFpr)
+   {
+      if (unlikely(k.empty()))
+	 continue;
+      if (k[0] == '/')
+      {
+	 Args.push_back("--keyring");
+	 Args.push_back(k.c_str());
+      }
+      else
+      {
+	 Args.push_back("--keyid");
+	 Args.push_back(k.c_str());
+      }
+   }
+   Args.push_back("verify");
+
+   char statusfdstr[10];
+   if (statusfd != -1)
+   {
+      Args.push_back("--status-fd");
+      snprintf(statusfdstr, sizeof(statusfdstr), "%i", statusfd);
+      Args.push_back(statusfdstr);
+   }
+
+   Configuration::Item const *Opts;
+   Opts = _config->Tree("Acquire::gpgv::Options");
+   if (Opts != 0)
+   {
+      Opts = Opts->Child;
+      for (; Opts != 0; Opts = Opts->Next)
+      {
+	 if (Opts->Value.empty())
+	    continue;
+	 Args.push_back(Opts->Value.c_str());
+      }
+   }
+
+   enum  { DETACHED, CLEARSIGNED } releaseSignature = (FileGPG != File) ? DETACHED : CLEARSIGNED;
+   auto sig = make_unique_char();
+   auto data = make_unique_char();
+   auto conf = make_unique_char();
+
+   // Dump the configuration so apt-key picks up the correct Dir values
+   {
+      {
+	 std::string tmpfile;
+	 strprintf(tmpfile, "%s/apt.conf.XXXXXX", GetTempDir().c_str());
+	 conf.reset(strdup(tmpfile.c_str()));
+      }
+      if (conf == nullptr) {
+	 apt_error(std::cerr, statusfd, fd, "Couldn't create tempfile names for passing config to apt-key");
+	 local_exit(EINTERNAL);
+      }
+      int confFd = mkstemp(conf.get());
+      if (confFd == -1) {
+	 apt_error(std::cerr, statusfd, fd, "Couldn't create temporary file %s for passing config to apt-key", conf.get());
+	 local_exit(EINTERNAL);
+      }
+      local_exit.files.push_back(conf.get());
+
+      std::ofstream confStream(conf.get());
+      close(confFd);
+      _config->Dump(confStream);
+      confStream.close();
+      setenv("APT_CONFIG", conf.get(), 1);
+   }
+
+   // Tell apt-key not to emit warnings
+   setenv("APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE", "1", 1);
+
+   if (releaseSignature == DETACHED)
+   {
+      auto detached = make_unique_FILE(FileGPG, "r");
+      if (detached.get() == nullptr)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' could not be opened", FileGPG.c_str());
+	 local_exit(EINTERNAL);
+      }
+      LineBuffer buf;
+      bool open_signature = false;
+      bool found_badcontent = false;
+      size_t found_signatures = 0;
+      while (buf.readFrom(detached.get(), FileGPG, true))
+      {
+	 if (open_signature)
+	 {
+	    if (buf == "-----END PGP SIGNATURE-----")
+	       open_signature = false;
+	    else if (buf.starts_with("-"))
+	    {
+	       // the used Radix-64 is not using dash for any value, so a valid line can't
+	       // start with one. Header keys could, but no existent one does and seems unlikely.
+	       // Instead it smells a lot like a header the parser didn't recognize.
+	       apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains unexpected line starting with a dash", FileGPG.c_str());
+	       local_exit(112);
+	    }
+	 }
+	 else //if (not open_signature)
+	 {
+	    if (buf == "-----BEGIN PGP SIGNATURE-----")
+	    {
+	       open_signature = true;
+	       ++found_signatures;
+	       if (found_badcontent)
+		  break;
+	    }
+	    else
+	    {
+	       found_badcontent = true;
+	       if (found_signatures != 0)
+		  break;
+	    }
+	 }
+      }
+      if (found_signatures == 0 && statusfd != -1)
+      {
+	 auto const errtag = "[GNUPG:] NODATA\n";
+	 FileFd::Write(fd[1], errtag, strlen(errtag));
+	 // guess if this is a binary signature, we never officially supported them,
+	 // but silently accepted them via passing them unchecked to gpgv
+	 if (found_badcontent)
+	 {
+	    rewind(detached.get());
+	    auto ptag = fgetc(detached.get());
+	    // §4.2 says that the first bit is always set and gpg seems to generate
+	    // only old format which is indicated by the second bit not set
+	    if (ptag != EOF && (ptag & 0x80) != 0 && (ptag & 0x40) == 0)
+	    {
+	       apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' is in unsupported binary format", FileGPG.c_str());
+	       local_exit(112);
+	    }
+	 }
+	 // This is not an attack attempt but a file even gpgv would complain about
+	 // likely the result of a paywall which is covered by the gpgv method
+	 local_exit(113);
+      }
+      else if (found_badcontent)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains lines not belonging to a signature", FileGPG.c_str());
+	 local_exit(112);
+      }
+      if (open_signature)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains unclosed signatures", FileGPG.c_str());
+	 local_exit(112);
+      }
+
+      Args.push_back(FileGPG.c_str());
+      Args.push_back(File.c_str());
+   }
+   else // clear-signed file
+   {
+      FileFd signature;
+      if (GetTempFile("apt.sig", false, &signature) == nullptr)
+	 local_exit(EINTERNAL);
+      sig.reset(strdup(signature.Name().c_str()));
+      local_exit.files.push_back(sig.get());
+      FileFd message;
+      if (GetTempFile("apt.data", false, &message) == nullptr)
+	 local_exit(EINTERNAL);
+      data.reset(strdup(message.Name().c_str()));
+      local_exit.files.push_back(data.get());
+
+      if (signature.Failed() || message.Failed() ||
+	  not SplitClearSignedFile(File, &message, nullptr, &signature))
+      {
+	 apt_error(std::cerr, statusfd, fd, "Splitting up %s into data and signature failed", File.c_str());
+	 local_exit(112);
+      }
+      Args.push_back(sig.get());
+      Args.push_back(data.get());
+   }
+
+   Args.push_back(NULL);
+
+   if (Debug)
+   {
+      std::clog << "Preparing to exec: ";
+      for (std::vector<const char *>::const_iterator a = Args.begin(); *a != NULL; ++a)
+	 std::clog << " " << *a;
+      std::clog << std::endl;
+   }
+
+   if (statusfd != -1)
+   {
+      int const nullfd = open("/dev/null", O_WRONLY);
+      close(fd[0]);
+      // Redirect output to /dev/null; we read from the status fd
+      if (statusfd != STDOUT_FILENO)
+	 dup2(nullfd, STDOUT_FILENO);
+      if (statusfd != STDERR_FILENO)
+	 dup2(nullfd, STDERR_FILENO);
+      // Redirect the pipe to the status fd (3)
+      dup2(fd[1], statusfd);
+
+      putenv((char *)"LANG=");
+      putenv((char *)"LC_ALL=");
+      putenv((char *)"LC_MESSAGES=");
+   }
+
+
+   // We have created tempfiles we have to clean up
+   // and we do an additional check, so fork yet another time …
+   pid_t pid = ExecFork();
+   if(pid < 0) {
+      apt_error(std::cerr, statusfd, fd, "Fork failed for %s to check %s", Args[0], File.c_str());
+      local_exit(EINTERNAL);
+   }
+   if(pid == 0)
+   {
+      if (statusfd != -1)
+	 dup2(fd[1], statusfd);
+      execvp(Args[0], (char **) &Args[0]);
+      apt_error(std::cerr, statusfd, fd, "Couldn't execute %s to check %s", Args[0], File.c_str());
+      local_exit(EINTERNAL);
+   }
+
+   // Wait and collect the error code - taken from WaitPid as we need the exact Status
+   int Status;
+   while (waitpid(pid,&Status,0) != pid)
+   {
+      if (errno == EINTR)
+	 continue;
+      apt_error(std::cerr, statusfd, fd, _("Waited for %s but it wasn't there"), "apt-key");
+      local_exit(EINTERNAL);
+   }
+
+   // check if it exit'ed normally …
+   if (not WIFEXITED(Status))
+   {
+      apt_error(std::cerr, statusfd, fd, _("Sub-process %s exited unexpectedly"), "apt-key");
+      local_exit(EINTERNAL);
+   }
+
+   // … and with a good exit code
+   if (WEXITSTATUS(Status) != 0)
+   {
+      // we forward the statuscode, so don't generate a message on the fd in this case
+      apt_error(std::cerr, -1, fd, _("Sub-process %s returned an error code (%u)"), "apt-key", WEXITSTATUS(Status));
+      local_exit(WEXITSTATUS(Status));
+   }
+
+   // everything fine
+   local_exit(0);
+}
+									/*}}}*/
+// SplitClearSignedFile - split message into data/signature		/*{{{*/
+bool SplitClearSignedFile(std::string const &InFile, FileFd * const ContentFile,
+      std::vector<std::string> * const ContentHeader, FileFd * const SignatureFile)
+{
+   auto in = make_unique_FILE(InFile, "r");
+   if (in.get() == nullptr)
+      return _error->Errno("fopen", "can not open %s", InFile.c_str());
+
+   struct ScopedErrors
+   {
+      ScopedErrors() { _error->PushToStack(); }
+      ~ScopedErrors() { _error->MergeWithStack(); }
+   } scoped;
+   LineBuffer buf;
+
+   // start of the message
+   if (not buf.readFrom(in.get(), InFile))
+      return false; // empty or read error
+   if (buf != "-----BEGIN PGP SIGNED MESSAGE-----")
+   {
+      // this might be an unsigned file we don't want to report errors for,
+      // but still finish unsuccessful none the less.
+      while (buf.readFrom(in.get(), InFile, true))
+	 if (buf == "-----BEGIN PGP SIGNED MESSAGE-----")
+	    return _error->Error("Clearsigned file '%s' does not start with a signed message block.", InFile.c_str());
+
+      return false;
+   }
+
+   // save "Hash" Armor Headers
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile))
+	 return false;
+      if (buf.empty())
+	 break; // empty line ends the Armor Headers
+      if (buf.starts_with("-"))
+	 // § 6.2 says unknown keys should be reported to the user. We don't go that far,
+	 // but we assume that there will never be a header key starting with a dash
+	 return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "armor");
+      if (ContentHeader != nullptr && buf.starts_with("Hash: "))
+	 ContentHeader->push_back(buf.view().to_string());
+   }
+
+   // the message itself
+   bool first_line = true;
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile))
+	 return false;
+
+      if (buf.starts_with("-"))
+      {
+	 if (buf == "-----BEGIN PGP SIGNATURE-----")
+	 {
+	    if (not buf.writeLineTo(SignatureFile))
+	       return false;
+	    break;
+	 }
+	 else if (buf.starts_with("- "))
+	 {
+	    // we don't have any fields which need to be dash-escaped,
+	    // but implementations are free to escape all lines …
+	    if (not buf.writeNewLineIf(ContentFile, not first_line) || not buf.writeTo(ContentFile, 2))
+	       return false;
+	 }
+	 else
+	    // § 7.1 says a client should warn, but we don't really work with files which
+	    // should contain lines starting with a dash, so it is a lot more likely that
+	    // this is an attempt to trick our parser vs. gpgv parser into ignoring a header
+	    return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "msg");
+      }
+      else if (not buf.writeNewLineIf(ContentFile, not first_line) || not buf.writeTo(ContentFile))
+	 return false;
+      first_line = false;
+   }
+
+   // collect all signatures
+   bool open_signature = true;
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile, true))
+	 break;
+
+      if (open_signature)
+      {
+	 if (buf == "-----END PGP SIGNATURE-----")
+	    open_signature = false;
+	 else if (buf.starts_with("-"))
+	    // the used Radix-64 is not using dash for any value, so a valid line can't
+	    // start with one. Header keys could, but no existent one does and seems unlikely.
+	    // Instead it smells a lot like a header the parser didn't recognize.
+	    return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "sig");
+      }
+      else //if (not open_signature)
+      {
+	 if (buf == "-----BEGIN PGP SIGNATURE-----")
+	    open_signature = true;
+	 else
+	    return _error->Error("Clearsigned file '%s' contains unsigned lines.", InFile.c_str());
+      }
+
+      if (not buf.writeLineTo(SignatureFile))
+	 return false;
+   }
+   if (open_signature)
+      return _error->Error("Signature in file %s wasn't closed", InFile.c_str());
+
+   // Flush the files
+   if (SignatureFile != nullptr)
+      SignatureFile->Flush();
+   if (ContentFile != nullptr)
+      ContentFile->Flush();
+
+   // Catch-all for "unhandled" read/sync errors
+   if (_error->PendingError())
+      return false;
+   return true;
+}
+									/*}}}*/
+bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile) /*{{{*/
+{
+   // Buffered file
+   if (GetTempFile("clearsigned.message", true, &MessageFile, true) == nullptr)
+      return false;
+   if (MessageFile.Failed())
+      return _error->Error("Couldn't open temporary file to work with %s", ClearSignedFileName.c_str());
+
+   _error->PushToStack();
+   bool const splitDone = SplitClearSignedFile(ClearSignedFileName, &MessageFile, NULL, NULL);
+   bool const errorDone = _error->PendingError();
+   _error->MergeWithStack();
+   if (not splitDone)
+   {
+      MessageFile.Close();
+
+      if (errorDone)
+	 return false;
+
+      // we deal with an unsigned file
+      MessageFile.Open(ClearSignedFileName, FileFd::ReadOnly);
+   }
+   else // clear-signed
+   {
+      if (not MessageFile.Seek(0))
+	 return _error->Errno("lseek", "Unable to seek back in message for file %s", ClearSignedFileName.c_str());
+   }
+
+   return not MessageFile.Failed();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/gpgv.h b/apt-pkg/contrib/gpgv.h
new file mode 100644
index 0000000..1cabed4
--- /dev/null
+++ b/apt-pkg/contrib/gpgv.h
@@ -0,0 +1,89 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Helpers to deal with gpgv better and more easily
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef CONTRIB_GPGV_H
+#define CONTRIB_GPGV_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+#include <vector>
+
+
+class FileFd;
+
+/** \brief generates and run the command to verify a file with gpgv
+ *
+ * If File and FileSig specify the same file it is assumed that we
+ * deal with a clear-signed message. Note that the method will accept
+ * and validate files which include additional (unsigned) messages
+ * without complaining. Do NOT open files accepted by this method
+ * for reading. Use #OpenMaybeClearSignedFile to access the message
+ * instead to ensure you are only reading signed data.
+ *
+ * The method does not return, but has some notable exit-codes:
+ * 111 signals an internal error like the inability to execute gpgv,
+ * 112 indicates a clear-signed file which doesn't include a message,
+ *  which can happen if APT is run while on a network requiring
+ *  authentication before usage (e.g. in hotels)
+ * All other exit-codes are passed-through from gpgv.
+ *
+ * @param File is the message (unsigned or clear-signed)
+ * @param FileSig is the signature (detached or clear-signed)
+ * @param statusfd is the fd given to gpgv as --status-fd
+ * @param fd is used as a pipe for the standard output of gpgv
+ * @param key is the specific one to be used instead of using all
+ */
+APT_PUBLIC void ExecGPGV(std::string const &File, std::string const &FileSig,
+      int const &statusfd, int fd[2], std::string const &Key = "") APT_NORETURN;
+inline APT_NORETURN void ExecGPGV(std::string const &File, std::string const &FileSig,
+      int const &statusfd = -1) {
+   int fd[2];
+   ExecGPGV(File, FileSig, statusfd, fd);
+}
+
+/** \brief Split an inline signature into message and signature
+ *
+ *  Takes a clear-signed message and puts the first signed message
+ *  in the content file and all signatures following it into the
+ *  second. Unsigned messages, additional messages as well as
+ *  whitespaces are discarded. The resulting files are suitable to
+ *  be checked with gpgv.
+ *
+ *  If a FileFd pointers is NULL it will not be used and the content
+ *  which would have been written to it is silently discarded.
+ *
+ *  The content of the split files is undefined if the splitting was
+ *  unsuccessful.
+ *
+ *  Note that trying to split an unsigned file will fail, but
+ *  not generate an error message.
+ *
+ *  @param InFile is the clear-signed file
+ *  @param ContentFile is the FileFd the message will be written to
+ *  @param ContentHeader is a list of all required Amored Headers for the message
+ *  @param SignatureFile is the FileFd all signatures will be written to
+ *  @return true if the splitting was successful, false otherwise
+ */
+APT_PUBLIC bool SplitClearSignedFile(std::string const &InFile, FileFd * const ContentFile,
+      std::vector<std::string> * const ContentHeader, FileFd * const SignatureFile);
+
+/** \brief open a file which might be clear-signed
+ *
+ * This method tries to extract the (signed) message of a file.
+ * If the file isn't signed it will just open the given filename.
+ * Otherwise the message is extracted to a temporary file which
+ * will be opened instead.
+ *
+ * @param ClearSignedFileName is the name of the file to open
+ * @param[out] MessageFile is the FileFd in which the file will be opened
+ * @return true if opening was successful, otherwise false
+ */
+APT_PUBLIC bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile);
+
+#endif
diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
new file mode 100644
index 0000000..313b1d3
--- /dev/null
+++ b/apt-pkg/contrib/hashes.cc
@@ -0,0 +1,464 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Hashes - Simple wrapper around the hash functions
+   
+   This is just used to make building the methods simpler, this is the
+   only interface required..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <gcrypt.h>
+									/*}}}*/
+
+static const constexpr struct HashAlgo
+{
+   const char *name;
+   int gcryAlgo;
+   Hashes::SupportedHashes ourAlgo;
+} Algorithms[] = {
+   {"MD5Sum", GCRY_MD_MD5, Hashes::MD5SUM},
+   {"SHA1", GCRY_MD_SHA1, Hashes::SHA1SUM},
+   {"SHA256", GCRY_MD_SHA256, Hashes::SHA256SUM},
+   {"SHA512", GCRY_MD_SHA512, Hashes::SHA512SUM},
+};
+
+const char * HashString::_SupportedHashes[] =
+{
+   "SHA512", "SHA256", "SHA1", "MD5Sum", "Checksum-FileSize", NULL
+};
+std::vector<HashString::HashSupportInfo> HashString::SupportedHashesInfo()
+{
+   return {{
+      { "SHA512",  pkgTagSection::Key::SHA512,"Checksums-Sha512", pkgTagSection::Key::Checksums_Sha512},
+      { "SHA256", pkgTagSection::Key::SHA256, "Checksums-Sha256", pkgTagSection::Key::Checksums_Sha256},
+      { "SHA1", pkgTagSection::Key::SHA1, "Checksums-Sha1", pkgTagSection::Key::Checksums_Sha1 },
+      { "MD5Sum", pkgTagSection::Key::MD5sum, "Files", pkgTagSection::Key::Files },
+   }};
+}
+
+HashString::HashString()
+{
+}
+
+HashString::HashString(std::string Type, std::string Hash) : Type(Type), Hash(Hash)
+{
+}
+
+HashString::HashString(std::string StringedHash)			/*{{{*/
+{
+   if (StringedHash.find(":") == std::string::npos)
+   {
+      // legacy: md5sum without "MD5Sum:" prefix
+      if (StringedHash.size() == 32)
+      {
+	 Type = "MD5Sum";
+	 Hash = StringedHash;
+      }
+      if(_config->FindB("Debug::Hashes",false) == true)
+	 std::clog << "HashString(string): invalid StringedHash " << StringedHash << std::endl;
+      return;
+   }
+   std::string::size_type pos = StringedHash.find(":");
+   Type = StringedHash.substr(0,pos);
+   Hash = StringedHash.substr(pos+1, StringedHash.size() - pos);
+
+   if(_config->FindB("Debug::Hashes",false) == true)
+      std::clog << "HashString(string): " << Type << " : " << Hash << std::endl;
+}
+									/*}}}*/
+bool HashString::VerifyFile(std::string filename) const			/*{{{*/
+{
+   std::string fileHash = GetHashForFile(filename);
+
+   if(_config->FindB("Debug::Hashes",false) == true)
+      std::clog << "HashString::VerifyFile: got: " << fileHash << " expected: " << toStr() << std::endl;
+
+   return (fileHash == Hash);
+}
+									/*}}}*/
+bool HashString::FromFile(std::string filename)          		/*{{{*/
+{
+   // pick the strongest hash
+   if (Type == "")
+      Type = _SupportedHashes[0];
+
+   Hash = GetHashForFile(filename);
+   return true;
+}
+									/*}}}*/
+std::string HashString::GetHashForFile(std::string filename) const      /*{{{*/
+{
+   std::string fileHash;
+
+   FileFd Fd(filename, FileFd::ReadOnly);
+   if(strcasecmp(Type.c_str(), "MD5Sum") == 0)
+   {
+      Hashes MD5(Hashes::MD5SUM);
+      MD5.AddFD(Fd);
+      fileHash = MD5.GetHashString(Hashes::MD5SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA1") == 0)
+   {
+      Hashes SHA1(Hashes::SHA1SUM);
+      SHA1.AddFD(Fd);
+      fileHash = SHA1.GetHashString(Hashes::SHA1SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA256") == 0)
+   {
+      Hashes SHA256(Hashes::SHA256SUM);
+      SHA256.AddFD(Fd);
+      fileHash = SHA256.GetHashString(Hashes::SHA256SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA512") == 0)
+   {
+      Hashes SHA512(Hashes::SHA512SUM);
+      SHA512.AddFD(Fd);
+      fileHash = SHA512.GetHashString(Hashes::SHA512SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "Checksum-FileSize") == 0)
+      strprintf(fileHash, "%llu", Fd.FileSize());
+   Fd.Close();
+
+   return fileHash;
+}
+									/*}}}*/
+const char** HashString::SupportedHashes()				/*{{{*/
+{
+   return _SupportedHashes;
+}
+									/*}}}*/
+APT_PURE bool HashString::empty() const					/*{{{*/
+{
+   return (Type.empty() || Hash.empty());
+}
+									/*}}}*/
+
+APT_PURE static bool IsConfigured(const char *name, const char *what)
+{
+   std::string option;
+   strprintf(option, "APT::Hashes::%s::%s", name, what);
+   return _config->FindB(option, false);
+}
+
+APT_PURE bool HashString::usable() const				/*{{{*/
+{
+   return (
+      (Type != "Checksum-FileSize") &&
+      (Type != "MD5Sum") &&
+      (Type != "SHA1") &&
+      !IsConfigured(Type.c_str(), "Untrusted")
+   );
+}
+									/*}}}*/
+std::string HashString::toStr() const					/*{{{*/
+{
+   return Type + ":" + Hash;
+}
+									/*}}}*/
+APT_PURE bool HashString::operator==(HashString const &other) const	/*{{{*/
+{
+   return (strcasecmp(Type.c_str(), other.Type.c_str()) == 0 && Hash == other.Hash);
+}
+APT_PURE bool HashString::operator!=(HashString const &other) const
+{
+   return !(*this == other);
+}
+									/*}}}*/
+
+bool HashStringList::usable() const					/*{{{*/
+{
+   if (empty() == true)
+      return false;
+   std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+   if (forcedType.empty() == true)
+   {
+      // See if there is at least one usable hash
+      return std::any_of(list.begin(), list.end(), [](auto const &hs) { return hs.usable(); });
+   }
+   return find(forcedType) != NULL;
+}
+									/*}}}*/
+HashString const * HashStringList::find(char const * const type) const /*{{{*/
+{
+   if (type == NULL || type[0] == '\0')
+   {
+      std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+      if (forcedType.empty() == false)
+	 return find(forcedType.c_str());
+      for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t)
+	 for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs)
+	    if (strcasecmp(hs->HashType().c_str(), *t) == 0)
+	       return &*hs;
+      return NULL;
+   }
+   for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs)
+      if (strcasecmp(hs->HashType().c_str(), type) == 0)
+	 return &*hs;
+   return NULL;
+}
+									/*}}}*/
+unsigned long long HashStringList::FileSize() const			/*{{{*/
+{
+   HashString const * const hsf = find("Checksum-FileSize");
+   if (hsf == NULL)
+      return 0;
+   std::string const hv = hsf->HashValue();
+   return strtoull(hv.c_str(), NULL, 10);
+}
+									/*}}}*/
+bool HashStringList::FileSize(unsigned long long const Size)		/*{{{*/
+{
+   return push_back(HashString("Checksum-FileSize", std::to_string(Size)));
+}
+									/*}}}*/
+bool HashStringList::supported(char const * const type)			/*{{{*/
+{
+   for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t)
+      if (strcasecmp(*t, type) == 0)
+	 return true;
+   return false;
+}
+									/*}}}*/
+bool HashStringList::push_back(const HashString &hashString)		/*{{{*/
+{
+   if (hashString.HashType().empty() == true ||
+	 hashString.HashValue().empty() == true ||
+	 supported(hashString.HashType().c_str()) == false)
+      return false;
+
+   // ensure that each type is added only once
+   HashString const * const hs = find(hashString.HashType().c_str());
+   if (hs != NULL)
+      return *hs == hashString;
+
+   list.push_back(hashString);
+   return true;
+}
+									/*}}}*/
+bool HashStringList::VerifyFile(std::string filename) const		/*{{{*/
+{
+   if (usable() == false)
+      return false;
+
+   Hashes hashes(*this);
+   FileFd file(filename, FileFd::ReadOnly);
+   HashString const * const hsf = find("Checksum-FileSize");
+   if (hsf != NULL)
+   {
+      std::string fileSize;
+      strprintf(fileSize, "%llu", file.FileSize());
+      if (hsf->HashValue() != fileSize)
+	 return false;
+   }
+   hashes.AddFD(file);
+   HashStringList const hsl = hashes.GetHashStringList();
+   return hsl == *this;
+}
+									/*}}}*/
+bool HashStringList::operator==(HashStringList const &other) const	/*{{{*/
+{
+   std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+   if (forcedType.empty() == false)
+   {
+      HashString const * const hs = find(forcedType);
+      HashString const * const ohs = other.find(forcedType);
+      if (hs == NULL || ohs == NULL)
+	 return false;
+      return *hs == *ohs;
+   }
+   short matches = 0;
+   for (const_iterator hs = begin(); hs != end(); ++hs)
+   {
+      HashString const * const ohs = other.find(hs->HashType());
+      if (ohs == NULL)
+	 continue;
+      if (*hs != *ohs)
+	 return false;
+      ++matches;
+   }
+   if (matches == 0)
+      return false;
+   return true;
+}
+bool HashStringList::operator!=(HashStringList const &other) const
+{
+   return !(*this == other);
+}
+									/*}}}*/
+
+// PrivateHashes							/*{{{*/
+class PrivateHashes {
+public:
+   unsigned long long FileSize;
+   gcry_md_hd_t hd;
+
+   void maybeInit()
+   {
+
+      // Yikes, we got to initialize libgcrypt, or we get warnings. But we
+      // abstract away libgcrypt in Hashes from our users - they are not
+      // supposed to know what the hashing backend is, so we can't force
+      // them to init themselves as libgcrypt folks want us to. So this
+      // only leaves us with this option...
+      if (!gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
+      {
+	 if (!gcry_check_version(nullptr))
+	 {
+	    fprintf(stderr, "libgcrypt is too old (need %s, have %s)\n",
+		    "nullptr", gcry_check_version(NULL));
+	    exit(2);
+	 }
+
+	 gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+      }
+   }
+
+   explicit PrivateHashes(unsigned int const CalcHashes) : FileSize(0)
+   {
+      maybeInit();
+      gcry_md_open(&hd, 0, 0);
+      for (auto & Algo : Algorithms)
+      {
+	 if ((CalcHashes & Algo.ourAlgo) == Algo.ourAlgo)
+	    gcry_md_enable(hd, Algo.gcryAlgo);
+      }
+   }
+
+   explicit PrivateHashes(HashStringList const &Hashes) : FileSize(0) {
+      maybeInit();
+      gcry_md_open(&hd, 0, 0);
+      for (auto & Algo : Algorithms)
+      {
+	 if (not Hashes.usable() || Hashes.find(Algo.name) != NULL)
+	    gcry_md_enable(hd, Algo.gcryAlgo);
+      }
+   }
+   ~PrivateHashes()
+   {
+      gcry_md_close(hd);
+   }
+};
+									/*}}}*/
+// Hashes::Add* - Add the contents of data or FD			/*{{{*/
+bool Hashes::Add(const unsigned char * const Data, unsigned long long const Size)
+{
+   if (Size != 0)
+   {
+      gcry_md_write(d->hd, Data, Size);
+      d->FileSize += Size;
+   }
+   return true;
+}
+bool Hashes::AddFD(int const Fd,unsigned long long Size)
+{
+   unsigned char Buf[APT_BUFFER_SIZE];
+   bool const ToEOF = (Size == UntilEOF);
+   while (Size != 0 || ToEOF)
+   {
+      decltype(Size) n = sizeof(Buf);
+      if (!ToEOF) n = std::min(Size, n);
+      ssize_t const Res = read(Fd,Buf,n);
+      if (Res < 0 || (!ToEOF && Res != (ssize_t) n)) // error, or short read
+	 return false;
+      if (ToEOF && Res == 0) // EOF
+	 break;
+      Size -= Res;
+      if (Add(Buf, Res) == false)
+	 return false;
+   }
+   return true;
+}
+bool Hashes::AddFD(FileFd &Fd,unsigned long long Size)
+{
+   unsigned char Buf[APT_BUFFER_SIZE];
+   bool const ToEOF = (Size == 0);
+   while (Size != 0 || ToEOF)
+   {
+      decltype(Size) n = sizeof(Buf);
+      if (!ToEOF) n = std::min(Size, n);
+      decltype(Size) a = 0;
+      if (Fd.Read(Buf, n, &a) == false) // error
+	 return false;
+      if (ToEOF == false)
+      {
+	 if (a != n) // short read
+	    return false;
+      }
+      else if (a == 0) // EOF
+	 break;
+      Size -= a;
+      if (Add(Buf, a) == false)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+
+static APT_PURE std::string HexDigest(gcry_md_hd_t hd, int algo)
+{
+   char Conv[16] =
+      {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',
+       'c', 'd', 'e', 'f'};
+
+   auto Size = gcry_md_get_algo_dlen(algo);
+   assert(Size <= 512/8);
+   char Result[((Size)*2) + 1];
+   Result[(Size)*2] = 0;
+
+   auto Sum = gcry_md_read(hd, algo);
+
+   // Convert each char into two letters
+   size_t J = 0;
+   size_t I = 0;
+   for (; I != (Size)*2; J++, I += 2)
+   {
+      Result[I] = Conv[Sum[J] >> 4];
+      Result[I + 1] = Conv[Sum[J] & 0xF];
+   }
+   return std::string(Result);
+};
+
+HashStringList Hashes::GetHashStringList()
+{
+   HashStringList hashes;
+   for (auto & Algo : Algorithms)
+      if (gcry_md_is_enabled(d->hd, Algo.gcryAlgo))
+	 hashes.push_back(HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo)));
+   hashes.FileSize(d->FileSize);
+
+   return hashes;
+}
+
+HashString Hashes::GetHashString(SupportedHashes hash)
+{
+   for (auto & Algo : Algorithms)
+      if (hash == Algo.ourAlgo)
+	 return HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo));
+
+   abort();
+}
+Hashes::Hashes() : d(new PrivateHashes(~0)) { }
+Hashes::Hashes(unsigned int const Hashes) : d(new PrivateHashes(Hashes)) {}
+Hashes::Hashes(HashStringList const &Hashes) : d(new PrivateHashes(Hashes)) {}
+Hashes::~Hashes() { delete d; }
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
new file mode 100644
index 0000000..e259b4e
--- /dev/null
+++ b/apt-pkg/contrib/hashes.h
@@ -0,0 +1,222 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Hashes - Simple wrapper around the hash functions
+   
+   This is just used to make building the methods simpler, this is the
+   only interface required..
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef APTPKG_HASHES_H
+#define APTPKG_HASHES_H
+
+#include <apt-pkg/macros.h>
+
+#ifdef APT_COMPILING_APT
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/tagfile-keys.h>
+#endif
+
+#include <cstring>
+#include <string>
+#include <vector>
+
+
+
+class FileFd;
+
+// helper class that contains hash function name
+// and hash
+class APT_PUBLIC HashString
+{
+ protected:
+   std::string Type;
+   std::string Hash;
+   static const char * _SupportedHashes[10];
+
+   // internal helper
+   std::string GetHashForFile(std::string filename) const;
+
+ public:
+   HashString(std::string Type, std::string Hash);
+   explicit HashString(std::string StringedHashString);  // init from str as "type:hash"
+   HashString();
+
+   // get hash type used
+   std::string HashType() const { return Type; };
+   std::string HashValue() const { return Hash; };
+
+   // verify the given filename against the currently loaded hash
+   bool VerifyFile(std::string filename) const;
+
+   // generate a hash string from the given filename
+   bool FromFile(std::string filename);
+
+
+   // helper
+   std::string toStr() const;                    // convert to str as "type:hash"
+   bool empty() const;
+   bool usable() const;
+   bool operator==(HashString const &other) const;
+   bool operator!=(HashString const &other) const;
+
+   // return the list of hashes we support
+   static APT_PURE const char** SupportedHashes();
+#ifdef APT_COMPILING_APT
+   struct APT_HIDDEN HashSupportInfo {
+      APT::StringView name;
+      pkgTagSection::Key namekey;
+      APT::StringView chksumsname;
+      pkgTagSection::Key chksumskey;
+   };
+   APT_HIDDEN static std::vector<HashSupportInfo> SupportedHashesInfo();
+#endif
+};
+
+class APT_PUBLIC HashStringList
+{
+   public:
+   /** find best hash if no specific one is requested
+    *
+    * @param type of the checksum to return, can be \b NULL
+    * @return If type is \b NULL (or the empty string) it will
+    *  return the 'best' hash; otherwise the hash which was
+    *  specifically requested. If no hash is found \b NULL will be returned.
+    */
+   HashString const * find(char const * const type) const;
+   HashString const * find(std::string const &type) const { return find(type.c_str()); }
+
+   /** finds the filesize hash and returns it as number
+    *
+    * @return beware: if the size isn't known we return \b 0 here,
+    * just like we would do for an empty file. If that is a problem
+    * for you have to get the size manually out of the list.
+    */
+   unsigned long long FileSize() const;
+
+   /** sets the filesize hash
+    *
+    * @param Size of the file
+    * @return @see #push_back
+    */
+   bool FileSize(unsigned long long const Size);
+
+   /** check if the given hash type is supported
+    *
+    * @param type to check
+    * @return true if supported, otherwise false
+    */
+   static APT_PURE bool supported(char const * const type);
+   /** add the given #HashString to the list
+    *
+    * @param hashString to add
+    * @return true if the hash is added because it is supported and
+    *  not already a different hash of the same type included, otherwise false
+    */
+   bool push_back(const HashString &hashString);
+   /** @return size of the list of HashStrings */
+   size_t size() const { return list.size(); }
+
+   /** verify file against all hashes in the list
+    *
+    * @param filename to verify
+    * @return true if the file matches the hashsum, otherwise false
+    */
+   bool VerifyFile(std::string filename) const;
+
+   /** is the list empty ?
+    *
+    * @return \b true if the list is empty, otherwise \b false
+    */
+   bool empty() const { return list.empty(); }
+
+   /** has the list at least one good entry
+    *
+    * similar to #empty, but handles forced hashes.
+    *
+    * @return if no hash is forced, same result as #empty,
+    * if one is forced \b true if this has is available, \b false otherwise
+    */
+   bool usable() const;
+
+   typedef std::vector<HashString>::const_iterator const_iterator;
+
+   /** iterator to the first element */
+   const_iterator begin() const { return list.begin(); }
+
+   /** iterator to the end element */
+   const_iterator end() const { return list.end(); }
+
+   /** start fresh with a clear list */
+   void clear() { list.clear(); }
+
+   /** compare two HashStringList for similarity.
+    *
+    * Two lists are similar if at least one hashtype is in both lists
+    * and the hashsum matches. All hashes are checked by default,
+    * if one doesn't match false is returned regardless of how many
+    * matched before. If a hash is forced, only this hash is compared,
+    * all others are ignored.
+    */
+   bool operator==(HashStringList const &other) const;
+   bool operator!=(HashStringList const &other) const;
+
+   HashStringList() {}
+
+   // simplifying API-compatibility constructors
+   explicit HashStringList(std::string const &hash) {
+      if (hash.empty() == false)
+	 list.push_back(HashString(hash));
+   }
+   explicit HashStringList(char const * const hash) {
+      if (hash != NULL && hash[0] != '\0')
+	 list.push_back(HashString(hash));
+   }
+
+   private:
+   std::vector<HashString> list;
+};
+
+class PrivateHashes;
+class APT_PUBLIC Hashes
+{
+   PrivateHashes * const d;
+   public:
+   static const int UntilEOF = 0;
+
+   bool Add(const unsigned char * const Data, unsigned long long const Size) APT_NONNULL(2);
+   inline bool Add(const char * const Data) APT_NONNULL(2)
+   {return Add(reinterpret_cast<unsigned char const *>(Data),strlen(Data));};
+   inline bool Add(const char *const Data, unsigned long long const Size) APT_NONNULL(2)
+   {
+      return Add(reinterpret_cast<unsigned char const *>(Data), Size);
+   };
+   inline bool Add(const unsigned char * const Beg,const unsigned char * const End) APT_NONNULL(2,3)
+   {return Add(Beg,End-Beg);};
+
+   enum SupportedHashes { MD5SUM = (1 << 0), SHA1SUM = (1 << 1), SHA256SUM = (1 << 2),
+      SHA512SUM = (1 << 3) };
+   bool AddFD(int const Fd,unsigned long long Size = 0);
+   bool AddFD(FileFd &Fd,unsigned long long Size = 0);
+
+   HashStringList GetHashStringList();
+
+   /** Get a specific hash. It is an error to use a hash that was not hashes */
+   HashString GetHashString(SupportedHashes hash);
+
+   /** create a Hashes object to calculate all supported hashes
+    *
+    * If ALL is too much, you can limit which Hashes are calculated
+    * with the following other constructors which mention explicitly
+    * which hashes to generate. */
+   Hashes();
+   /** @param Hashes bitflag composed of #SupportedHashes */
+   explicit Hashes(unsigned int const Hashes);
+   /** @param Hashes is a list of hashes */
+   explicit Hashes(HashStringList const &Hashes);
+   virtual ~Hashes();
+};
+
+#endif
diff --git a/apt-pkg/contrib/header-is-private.h b/apt-pkg/contrib/header-is-private.h
new file mode 100644
index 0000000..201a40c
--- /dev/null
+++ b/apt-pkg/contrib/header-is-private.h
@@ -0,0 +1,3 @@
+#ifndef APT_COMPILING_APT
+#error Internal header without ABI stability. Should only be used by apt itself!
+#endif
diff --git a/apt-pkg/contrib/macros.h b/apt-pkg/contrib/macros.h
new file mode 100644
index 0000000..c08cd24
--- /dev/null
+++ b/apt-pkg/contrib/macros.h
@@ -0,0 +1,131 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Macros Header - Various useful macro definitions
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Brian C. White.
+   
+   ##################################################################### */
+									/*}}}*/
+// Private header
+#ifndef MACROS_H
+#define MACROS_H
+
+/* Useful count macro, use on an array of things and it will return the
+   number of items in the array */
+#define APT_ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+// Flag Macros
+#define	FLAG(f)			(1L << (f))
+#define	SETFLAG(v,f)	((v) |= FLAG(f))
+#define CLRFLAG(v,f)	((v) &=~FLAG(f))
+#define	CHKFLAG(v,f)	((v) &  FLAG(f) ? true : false)
+
+#ifdef __GNUC__
+#define APT_GCC_VERSION (__GNUC__ << 8 | __GNUC_MINOR__)
+#else
+#define APT_GCC_VERSION 0
+#endif
+
+#ifdef APT_COMPILING_APT
+/* likely() and unlikely() can be used to mark boolean expressions
+   as (not) likely true which will help the compiler to optimise */
+#if APT_GCC_VERSION >= 0x0300
+	#define likely(x)	__builtin_expect (!!(x), 1)
+	#define unlikely(x)	__builtin_expect (!!(x), 0)
+#else
+	#define likely(x)	(x)
+	#define unlikely(x)	(x)
+#endif
+#endif
+
+#if APT_GCC_VERSION >= 0x0300
+	#define APT_DEPRECATED	__attribute__ ((deprecated))
+	#define APT_DEPRECATED_MSG(X)	__attribute__ ((deprecated(X)))
+	// __attribute__((const)) is too dangerous for us, we end up using it wrongly
+	#define APT_PURE	__attribute__((pure))
+	#define APT_NORETURN	__attribute__((noreturn))
+	#define APT_PRINTF(n)	__attribute__((format(printf, n, n + 1)))
+	#define APT_WEAK        __attribute__((weak));
+	#define APT_UNUSED      __attribute__((unused))
+#else
+	#define APT_DEPRECATED
+	#define APT_DEPRECATED_MSG
+	#define APT_PURE
+	#define APT_NORETURN
+	#define APT_PRINTF(n)
+	#define APT_WEAK
+	#define APT_UNUSED
+#endif
+
+#if APT_GCC_VERSION > 0x0302
+	#define APT_NONNULL(...)	__attribute__((nonnull(__VA_ARGS__)))
+	#define APT_MUSTCHECK		__attribute__((warn_unused_result))
+#else
+	#define APT_NONNULL(...)
+	#define APT_MUSTCHECK
+#endif
+
+#if APT_GCC_VERSION >= 0x0400
+	#define APT_SENTINEL	__attribute__((sentinel))
+	#define APT_PUBLIC __attribute__ ((visibility ("default")))
+	#define APT_HIDDEN __attribute__ ((visibility ("hidden")))
+#else
+	#define APT_SENTINEL
+	#define APT_PUBLIC
+	#define APT_HIDDEN
+#endif
+
+// cold functions are unlikely() to be called
+#if APT_GCC_VERSION >= 0x0403
+	#define APT_COLD	__attribute__ ((__cold__))
+	#define APT_HOT		__attribute__ ((__hot__))
+#else
+	#define APT_COLD
+	#define APT_HOT
+#endif
+
+
+#if __GNUC__ >= 4
+	#define APT_IGNORE_DEPRECATED_PUSH \
+		_Pragma("GCC diagnostic push") \
+		_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+	#define APT_IGNORE_DEPRECATED_POP \
+		_Pragma("GCC diagnostic pop")
+	/* gcc has various problems with this shortcut, so prefer the long form */
+	#define APT_IGNORE_DEPRECATED(XXX) \
+		APT_IGNORE_DEPRECATED_PUSH \
+		XXX \
+		APT_IGNORE_DEPRECATED_POP
+#else
+	#define APT_IGNORE_DEPRECATED_PUSH
+	#define APT_IGNORE_DEPRECATED_POP
+	#define APT_IGNORE_DEPRECATED(XXX) XXX
+#endif
+
+#if __cplusplus >= 201103L
+	#define APT_OVERRIDE override
+#else
+	#define APT_OVERRIDE /* no c++11 standard */
+#endif
+
+// These lines are extracted by the makefiles and the buildsystem
+// Increasing MAJOR or MINOR results in the need of recompiling all
+// reverse-dependencies of libapt-pkg against the new SONAME.
+// Non-ABI-Breaks should only increase RELEASE number.
+// See also buildlib/libversion.mak
+#define APT_PKG_MAJOR 6
+#define APT_PKG_MINOR 0
+#define APT_PKG_RELEASE 0
+#define APT_PKG_ABI ((APT_PKG_MAJOR * 100) + APT_PKG_MINOR)
+
+/* Should be a multiple of the common page size (4096) */
+static constexpr unsigned long long APT_BUFFER_SIZE = 64 * 1024;
+
+#endif
diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc
new file mode 100644
index 0000000..0568e1c
--- /dev/null
+++ b/apt-pkg/contrib/mmap.cc
@@ -0,0 +1,504 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   MMap Class - Provides 'real' mmap or a faked mmap using read().
+
+   MMap cover class.
+
+   Some broken versions of glibc2 (libc6) have a broken definition
+   of mmap that accepts a char * -- all other systems (and libc5) use
+   void *. We can't safely do anything here that would be portable, so
+   libc6 generates warnings -- which should be errors, g++ isn't properly
+   strict.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#define _DEFAULT_SOURCE
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/mmap.h>
+
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// MMap::MMap - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
+                     Base(nullptr), SyncToFd(nullptr)
+{
+   if ((Flags & NoImmMap) != NoImmMap)
+      Map(F);
+}
+									/*}}}*/
+// MMap::MMap - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
+                     Base(nullptr), SyncToFd(nullptr)
+{
+}
+									/*}}}*/
+// MMap::~MMap - Destructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::~MMap()
+{
+   Close();
+}
+									/*}}}*/
+// MMap::Map - Perform the mapping					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Map(FileFd &Fd)
+{
+   iSize = Fd.Size();
+
+   // Set the permissions.
+   int Prot = PROT_READ;
+   int Map = MAP_SHARED;
+   if ((Flags & ReadOnly) != ReadOnly)
+      Prot |= PROT_WRITE;
+   if ((Flags & Public) != Public)
+      Map = MAP_PRIVATE;
+   
+   if (iSize == 0)
+      return _error->Error(_("Can't mmap an empty file"));
+
+   // We can't mmap compressed fd's directly, so we need to read it completely
+   if (Fd.IsCompressed() == true)
+   {
+      if ((Flags & ReadOnly) != ReadOnly)
+	 return _error->Error("Compressed file %s can only be mapped readonly", Fd.Name().c_str());
+      Base = malloc(iSize);
+      if (unlikely(Base == nullptr))
+	 return _error->Errno("MMap-compressed-malloc", _("Couldn't make mmap of %llu bytes"), iSize);
+      SyncToFd = new FileFd();
+      if (Fd.Seek(0L) == false || Fd.Read(Base, iSize) == false)
+	 return _error->Error("Compressed file %s can't be read into mmap", Fd.Name().c_str());
+      return true;
+   }
+
+   // Map it.
+   Base = (Flags & Fallback) ? MAP_FAILED : mmap(0,iSize,Prot,Map,Fd.Fd(),0);
+   if (Base == MAP_FAILED)
+   {
+      if (errno == ENODEV || errno == EINVAL || (Flags & Fallback))
+      {
+	 // The filesystem doesn't support this particular kind of mmap.
+	 // So we allocate a buffer and read the whole file into it.
+	 if ((Flags & ReadOnly) == ReadOnly)
+	 {
+	    // for readonly, we don't need sync, so make it simple
+	    Base = malloc(iSize);
+	    if (unlikely(Base == nullptr))
+	       return _error->Errno("MMap-malloc", _("Couldn't make mmap of %llu bytes"), iSize);
+	    SyncToFd = new FileFd();
+	    return Fd.Read(Base, iSize);
+	 }
+	 // FIXME: Writing to compressed fd's ?
+	 int const dupped_fd = dup(Fd.Fd());
+	 if (dupped_fd == -1)
+	    return _error->Errno("mmap", _("Couldn't duplicate file descriptor %i"), Fd.Fd());
+
+	 Base = calloc(iSize, 1);
+	 if (unlikely(Base == nullptr))
+	    return _error->Errno("MMap-calloc", _("Couldn't make mmap of %llu bytes"), iSize);
+	 SyncToFd = new FileFd (dupped_fd);
+	 if (!SyncToFd->Seek(0L) || !SyncToFd->Read(Base, iSize))
+	    return false;
+      }
+      else
+	 return _error->Errno("MMap-mmap", _("Couldn't make mmap of %llu bytes"), iSize);
+     }
+
+   return true;
+}
+									/*}}}*/
+// MMap::Close - Close the map						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Close(bool DoSync)
+{
+   if ((Flags & UnMapped) == UnMapped || validData() == false || iSize == 0)
+      return true;
+   
+   if (DoSync == true)
+      Sync();
+
+   if (SyncToFd != NULL)
+   {
+      free(Base);
+      delete SyncToFd;
+      SyncToFd = NULL;
+   }
+   else
+   {
+      if (munmap((char *)Base, iSize) != 0)
+	 _error->WarningE("mmap", _("Unable to close mmap"));
+   }
+
+   iSize = 0;
+   Base = 0;
+   return true;
+}
+									/*}}}*/
+// MMap::Sync - Synchronize the map with the disk			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is done in synchronous mode - the docs indicate that this will 
+   not return till all IO is complete */
+bool MMap::Sync()
+{
+   if ((Flags & UnMapped) == UnMapped)
+      return true;
+
+   if ((Flags & ReadOnly) != ReadOnly)
+   {
+      if (SyncToFd != NULL)
+      {
+	 if (!SyncToFd->Seek(0) || !SyncToFd->Write(Base, iSize))
+	    return false;
+      }
+      else
+      {
+#ifdef _POSIX_SYNCHRONIZED_IO
+	 if (msync((char *)Base, iSize, MS_SYNC) < 0)
+	    return _error->Errno("msync", _("Unable to synchronize mmap"));
+#endif
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// MMap::Sync - Synchronize a section of the file to disk		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Sync(unsigned long Start,unsigned long Stop)
+{
+   if ((Flags & UnMapped) == UnMapped)
+      return true;
+
+   if ((Flags & ReadOnly) != ReadOnly)
+   {
+      if (SyncToFd != 0)
+      {
+	 if (!SyncToFd->Seek(0) ||
+	     !SyncToFd->Write (((char *)Base)+Start, Stop-Start))
+	    return false;
+      }
+      else
+      {
+#ifdef _POSIX_SYNCHRONIZED_IO
+	 unsigned long long const PSize = sysconf(_SC_PAGESIZE);
+	 if (msync((char *)Base+(Start/PSize)*PSize, Stop - Start, MS_SYNC) < 0)
+	    return _error->Errno("msync", _("Unable to synchronize mmap"));
+#endif
+      }
+   }
+   return true;
+}
+									/*}}}*/
+
+// DynamicMMap::DynamicMMap - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &Workspace,
+			 unsigned long const &Grow, unsigned long const &Limit) :
+		MMap(F,Flags | NoImmMap), Fd(&F), WorkSpace(Workspace),
+		GrowFactor(Grow), Limit(Limit)
+{
+   // disable Moveable if we don't grow
+   if (Grow == 0)
+      this->Flags &= ~Moveable;
+
+#ifndef __linux__
+   // kfreebsd doesn't have mremap, so we use the fallback
+   if ((this->Flags & Moveable) == Moveable)
+      this->Flags |= Fallback;
+#endif
+
+   unsigned long long EndOfFile = Fd->Size();
+   if (EndOfFile > WorkSpace)
+      WorkSpace = EndOfFile;
+   else if(WorkSpace > 0)
+   {
+      Fd->Seek(WorkSpace - 1);
+      char C = 0;
+      Fd->Write(&C,sizeof(C));
+   }
+   
+   Map(F);
+   iSize = EndOfFile;
+}
+									/*}}}*/
+// DynamicMMap::DynamicMMap - Constructor for a non-file backed map	/*{{{*/
+// ---------------------------------------------------------------------
+/* We try here to use mmap to reserve some space - this is much more
+   cooler than the fallback solution to simply allocate a char array
+   and could come in handy later than we are able to grow such an mmap */
+DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace,
+			 unsigned long const &Grow, unsigned long const &Limit) :
+		MMap(Flags | NoImmMap | UnMapped), Fd(0), WorkSpace(WorkSpace),
+		GrowFactor(Grow), Limit(Limit)
+{
+	// disable Moveable if we don't grow
+	if (Grow == 0)
+		this->Flags &= ~Moveable;
+
+#ifndef __linux__
+	// kfreebsd doesn't have mremap, so we use the fallback
+	if ((this->Flags & Moveable) == Moveable)
+		this->Flags |= Fallback;
+#endif
+
+#ifdef _POSIX_MAPPED_FILES
+	if ((this->Flags & Fallback) != Fallback) {
+		// Set the permissions.
+		int Prot = PROT_READ;
+#ifdef MAP_ANONYMOUS
+		int Map = MAP_PRIVATE | MAP_ANONYMOUS;
+#else
+		int Map = MAP_PRIVATE | MAP_ANON;
+#endif
+		if ((this->Flags & ReadOnly) != ReadOnly)
+			Prot |= PROT_WRITE;
+		if ((this->Flags & Public) == Public)
+#ifdef MAP_ANONYMOUS
+			Map = MAP_SHARED | MAP_ANONYMOUS;
+#else
+			Map = MAP_SHARED | MAP_ANON;
+#endif
+
+		// use anonymous mmap() to get the memory
+		Base = (unsigned char*) mmap(0, WorkSpace, Prot, Map, -1, 0);
+
+		if(Base == MAP_FAILED)
+			_error->Errno("DynamicMMap",_("Couldn't make mmap of %lu bytes"),WorkSpace);
+
+		iSize = 0;
+		return;
+	}
+#endif
+	// fallback to a static allocated space
+	Base = calloc(WorkSpace, 1);
+	iSize = 0;
+}
+									/*}}}*/
+// DynamicMMap::~DynamicMMap - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* We truncate the file to the size of the memory data set */
+DynamicMMap::~DynamicMMap()
+{
+   if (Fd == 0)
+   {
+      if (validData() == false)
+	 return;
+#ifdef _POSIX_MAPPED_FILES
+      munmap(Base, WorkSpace);
+#else
+      free(Base);
+#endif
+      return;
+   }
+   
+   unsigned long long EndOfFile = iSize;
+   iSize = WorkSpace;
+   Close(false);
+   if(ftruncate(Fd->Fd(),EndOfFile) < 0)
+      _error->Errno("ftruncate", _("Failed to truncate file"));
+}  
+									/*}}}*/
+// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space	/*{{{*/
+// ---------------------------------------------------------------------
+/* This allocates a block of memory aligned to the given size */
+unsigned long DynamicMMap::RawAllocate(unsigned long long Size,unsigned long Aln)
+{
+   unsigned long long Result = iSize;
+   if (Aln != 0)
+      Result += Aln - (iSize%Aln);
+
+   iSize = Result + Size;
+
+   // try to grow the buffer
+   while(Result + Size > WorkSpace)
+   {
+      if(!Grow())
+      {
+	 _error->Fatal(_("Dynamic MMap ran out of room. Please increase the size "
+			 "of APT::Cache-Start. Current value: %lu. (man 5 apt.conf)"), WorkSpace);
+	 return 0;
+      }
+   }
+   return Result;
+}
+									/*}}}*/
+// DynamicMMap::Allocate - Pooled aligned allocation			/*{{{*/
+// ---------------------------------------------------------------------
+/* This allocates an Item of size ItemSize so that it is aligned to its
+   size in the file. */
+unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
+{
+   if (unlikely(ItemSize == 0))
+   {
+      _error->Fatal("Can't allocate an item of size zero");
+      return 0;
+   }
+
+   // Look for a matching pool entry
+   Pool *I;
+   for (I = Pools; I != Pools + PoolCount; ++I)
+   {
+      if (I->ItemSize == ItemSize)
+	 break;
+   }
+   // No pool is allocated, use an unallocated one.
+   if (unlikely(I == Pools + PoolCount))
+   {
+      for (I = Pools; I != Pools + PoolCount; ++I)
+      {
+	 if (I->ItemSize == 0)
+	    break;
+      }
+      // Woops, we ran out, the calling code should allocate more.
+      if (I == Pools + PoolCount)
+      {
+	 _error->Error("Ran out of allocation pools");
+	 return 0;
+      }
+
+      I->ItemSize = ItemSize;
+      I->Count = 0;
+   }
+
+   unsigned long Result = 0;
+   // Out of space, allocate some more
+   if (I->Count == 0)
+   {
+      const unsigned long size = 20*1024;
+      I->Count = size/ItemSize;
+      Pool* oldPools = Pools;
+      _error->PushToStack();
+      Result = RawAllocate(size,ItemSize);
+      bool const newError = _error->PendingError();
+      _error->MergeWithStack();
+      if (Pools != oldPools)
+	 I = Pools + (I - oldPools);
+
+      // Does the allocation failed ?
+      if (Result == 0 && newError)
+	 return 0;
+      I->Start = Result;
+   }
+   else
+      Result = I->Start;
+
+   I->Count--;
+   I->Start += ItemSize;
+   return Result/ItemSize;
+}
+									/*}}}*/
+// DynamicMMap::WriteString - Write a string to the file		/*{{{*/
+// ---------------------------------------------------------------------
+/* Strings are aligned to 16 bytes */
+unsigned long DynamicMMap::WriteString(const char *String,
+				       unsigned long Len)
+{
+   if (Len == std::numeric_limits<unsigned long>::max())
+      Len = strlen(String);
+
+   _error->PushToStack();
+   unsigned long Result = RawAllocate(Len+1+sizeof(uint16_t),sizeof(uint16_t));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+
+   if (Base == NULL || (Result == 0 && newError))
+      return 0;
+
+   if (Len >= std::numeric_limits<uint16_t>::max())
+      abort();
+
+   uint16_t LenToWrite = Len;
+   memcpy((char *)Base + Result, &LenToWrite, sizeof(LenToWrite));
+   Result += + sizeof(LenToWrite);
+
+   memcpy((char *)Base + Result,String,Len);
+   ((char *)Base)[Result + Len] = 0;
+   return Result;
+}
+									/*}}}*/
+// DynamicMMap::Grow - Grow the mmap					/*{{{*/
+// ---------------------------------------------------------------------
+/* This method is a wrapper around different methods to (try to) grow
+   a mmap (or our char[]-fallback). Encounterable environments:
+   1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
+   2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+   3. Moveable + Fallback -> realloc
+   4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
+   5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+   6. !Moveable + Fallback -> not possible
+   [ While Moveable and Fallback stands for the equally named flags and
+     "linux" indicates a linux kernel instead of a freebsd kernel. ]
+   So what you can see here is, that a MMAP which want to be growable need
+   to be moveable to have a real chance but that this method will at least try
+   the nearly impossible 4 to grow it before it finally give up: Never say never. */
+bool DynamicMMap::Grow() {
+	if (Limit != 0 && WorkSpace >= Limit)
+		return _error->Error(_("Unable to increase the size of the MMap as the "
+		                       "limit of %lu bytes is already reached."), Limit);
+	if (GrowFactor <= 0)
+		return _error->Error(_("Unable to increase size of the MMap as automatic growing is disabled by user."));
+
+	unsigned long long const newSize = WorkSpace + GrowFactor;
+
+	if(Fd != 0) {
+		Fd->Seek(newSize - 1);
+		char C = 0;
+		Fd->Write(&C,sizeof(C));
+	}
+
+	unsigned long const poolOffset = Pools - ((Pool*) Base);
+
+	if ((Flags & Fallback) != Fallback) {
+#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
+   #ifdef MREMAP_MAYMOVE
+
+		if ((Flags & Moveable) == Moveable)
+			Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
+		else
+   #endif
+			Base = mremap(Base, WorkSpace, newSize, 0);
+
+		if(Base == MAP_FAILED)
+			return false;
+#else
+		return false;
+#endif
+	} else {
+		if ((Flags & Moveable) != Moveable)
+			return false;
+
+		Base = realloc(Base, newSize);
+		if (Base == NULL)
+			return false;
+		else
+			/* Set new memory to 0 */
+			memset((char*)Base + WorkSpace, 0, newSize - WorkSpace);
+	}
+
+	Pools =(Pool*) Base + poolOffset;
+	WorkSpace = newSize;
+	return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/mmap.h b/apt-pkg/contrib/mmap.h
new file mode 100644
index 0000000..fe834d5
--- /dev/null
+++ b/apt-pkg/contrib/mmap.h
@@ -0,0 +1,120 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   MMap Class - Provides 'real' mmap or a faked mmap using read().
+
+   The purpose of this code is to provide a generic way for clients to
+   access the mmap function. In environments that do not support mmap
+   from file fd's this function will use read and normal allocated 
+   memory.
+   
+   Writing to a public mmap will always fully commit all changes when the
+   class is deleted. Ie it will rewrite the file, unless it is readonly
+
+   The DynamicMMap class is used to help the on-disk data structure 
+   generators. It provides a large allocated workspace and members
+   to allocate space from the workspace in an efficient fashion.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_MMAP_H
+#define PKGLIB_MMAP_H
+
+#include <string>
+#include <limits>
+
+#include <sys/mman.h>
+
+
+class FileFd;
+
+/* This should be a 32 bit type, larger types use too much ram and smaller
+   types are too small. Where ever possible 'unsigned long' should be used
+   instead of this internal type */
+typedef unsigned int map_ptrloc;
+
+class MMap
+{
+   protected:
+   
+   unsigned long Flags;
+   unsigned long long iSize;
+   void *Base;
+
+   // In case mmap can not be used, we keep a dup of the file
+   // descriptor that should have been mmaped so that we can write to
+   // the file in Sync().
+   FileFd *SyncToFd;
+
+   bool Map(FileFd &Fd);
+   bool Close(bool DoSync = true);
+   
+   public:
+
+   enum OpenFlags {NoImmMap = (1<<0),Public = (1<<1),ReadOnly = (1<<2),
+                   UnMapped = (1<<3), Moveable = (1<<4), Fallback = (1 << 5)};
+      
+   // Simple accessors
+   inline operator void *() {return Base;};
+   inline void *Data() {return Base;}; 
+   inline unsigned long long Size() {return iSize;};
+   inline void AddSize(unsigned long long const size) {iSize += size;};
+   inline bool validData() const { return Base != MAP_FAILED && Base != 0; };
+   
+   // File manipulators
+   bool Sync();
+   bool Sync(unsigned long Start,unsigned long Stop);
+   
+   MMap(FileFd &F,unsigned long Flags);
+   explicit MMap(unsigned long Flags);
+   virtual ~MMap();
+};
+
+class DynamicMMap : public MMap
+{
+   public:
+   
+   // This is the allocation pool structure
+   struct Pool
+   {
+      unsigned long ItemSize;
+      unsigned long Start;
+      unsigned long Count;
+   };
+   
+   protected:
+   
+   FileFd *Fd;
+   unsigned long WorkSpace;
+   unsigned long const GrowFactor;
+   unsigned long const Limit;
+   Pool *Pools;
+   unsigned int PoolCount;
+
+   bool Grow();
+   
+   public:
+
+   // Allocation
+   unsigned long RawAllocate(unsigned long long Size,unsigned long Aln = 0);
+   unsigned long Allocate(unsigned long ItemSize);
+   unsigned long WriteString(const char *String,unsigned long Len = std::numeric_limits<unsigned long>::max());
+   inline unsigned long WriteString(const std::string &S) {return WriteString(S.c_str(),S.length());};
+   void UsePools(Pool &P,unsigned int Count) {Pools = &P; PoolCount = Count;};
+   
+   DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &WorkSpace = 2*1024*1024,
+	       unsigned long const &Grow = 1024*1024, unsigned long const &Limit = 0);
+   DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace = 2*1024*1024,
+	       unsigned long const &Grow = 1024*1024, unsigned long const &Limit = 0);
+   virtual ~DynamicMMap();
+};
+
+#endif
diff --git a/apt-pkg/contrib/netrc.cc b/apt-pkg/contrib/netrc.cc
new file mode 100644
index 0000000..ec694da
--- /dev/null
+++ b/apt-pkg/contrib/netrc.cc
@@ -0,0 +1,173 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   netrc file parser - returns the login and password of a give host in
+                       a specified netrc-type file
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Originally written by Daniel Stenberg, <daniel@haxx.se>, et al. and
+   placed into the Public Domain, do with it what you will.
+
+   ##################################################################### */
+									/*}}}*/
+#include <config.h>
+#include <apti18n.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <iostream>
+
+#include "netrc.h"
+
+/* Get user and password from .netrc when given a machine name */
+bool MaybeAddAuth(FileFd &NetRCFile, URI &Uri)
+{
+   if (Uri.User.empty() == false || Uri.Password.empty() == false)
+      return true;
+   if (NetRCFile.IsOpen() == false || NetRCFile.Failed())
+      return false;
+   auto const Debug = _config->FindB("Debug::Acquire::netrc", false);
+
+   std::string lookfor;
+   if (Uri.Port != 0)
+      strprintf(lookfor, "%s:%i%s", Uri.Host.c_str(), Uri.Port, Uri.Path.c_str());
+   else
+      lookfor.append(Uri.Host).append(Uri.Path);
+
+   enum
+   {
+      NO,
+      MACHINE,
+      GOOD_MACHINE,
+      LOGIN,
+      PASSWORD
+   } active_token = NO;
+   std::string line;
+   while (NetRCFile.Eof() == false || line.empty() == false)
+   {
+      bool protocolSpecified = false;
+
+      if (line.empty())
+      {
+	 if (NetRCFile.ReadLine(line) == false)
+	    break;
+	 else if (line.empty())
+	    continue;
+      }
+      auto tokenend = line.find_first_of("\t ");
+      std::string token;
+      if (tokenend != std::string::npos)
+      {
+	 token = line.substr(0, tokenend);
+	 line.erase(0, tokenend + 1);
+      }
+      else
+	 std::swap(line, token);
+      if (token.empty())
+	 continue;
+      switch (active_token)
+      {
+      case NO:
+	 if (token == "machine")
+	    active_token = MACHINE;
+	 break;
+      case MACHINE:
+	 // If token contains a protocol: Check it first, and strip it away if
+	 // it matches. If it does not match, ignore this stanza.
+	 // If there is no protocol, only allow https protocols.
+	 protocolSpecified = token.find("://") != std::string::npos;
+	 if (protocolSpecified)
+	 {
+	    if (not APT::String::Startswith(token, Uri.Access + "://"))
+	    {
+	       active_token = NO;
+	       break;
+	    }
+	    token.erase(0, Uri.Access.length() + 3);
+	 }
+
+	 if (token.find('/') == std::string::npos)
+	 {
+	    if (Uri.Port != 0 && Uri.Host == token)
+	       active_token = GOOD_MACHINE;
+	    else if (lookfor.compare(0, lookfor.length() - Uri.Path.length(), token) == 0)
+	       active_token = GOOD_MACHINE;
+	    else
+	       active_token = NO;
+	 }
+	 else
+	 {
+	    if (APT::String::Startswith(lookfor, token))
+	       active_token = GOOD_MACHINE;
+	    else
+	       active_token = NO;
+	 }
+
+	 if (active_token == GOOD_MACHINE && not protocolSpecified)
+	 {
+	    if (Uri.Access != "https" && Uri.Access != "tor+https")
+	    {
+	       _error->Warning(_("%s: Credentials for %s match, but the protocol is not encrypted. Annotate with %s:// to use."), NetRCFile.Name().c_str(), token.c_str(), Uri.Access.c_str());
+	       active_token = NO;
+	    }
+	 }
+	 break;
+      case GOOD_MACHINE:
+	 if (token == "login")
+	    active_token = LOGIN;
+	 else if (token == "password")
+	    active_token = PASSWORD;
+	 else if (token == "machine")
+	 {
+	    if (Debug)
+	       std::clog << "MaybeAddAuth: Found matching host adding '" << Uri.User << "' and '" << Uri.Password << "' for "
+			 << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+	    return true;
+	 }
+	 break;
+      case LOGIN:
+	 std::swap(Uri.User, token);
+	 active_token = GOOD_MACHINE;
+	 break;
+      case PASSWORD:
+	 std::swap(Uri.Password, token);
+	 active_token = GOOD_MACHINE;
+	 break;
+      }
+   }
+   if (active_token == GOOD_MACHINE)
+   {
+      if (Debug)
+	 std::clog << "MaybeAddAuth: Found matching host adding '" << Uri.User << "' and '" << Uri.Password << "' for "
+		   << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+      return true;
+   }
+   else if (active_token == NO)
+   {
+      if (Debug)
+	 std::clog << "MaybeAddAuth: Found no matching host for "
+		   << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+      return true;
+   }
+   else if (Debug)
+   {
+      std::clog << "MaybeAddAuth: Found no matching host (syntax error: token:";
+      switch (active_token)
+      {
+	 case NO: std::clog << "NO"; break;
+	 case MACHINE: std::clog << "MACHINE"; break;
+	 case GOOD_MACHINE: std::clog << "GOOD_MACHINE"; break;
+	 case LOGIN: std::clog << "LOGIN"; break;
+	 case PASSWORD: std::clog << "PASSWORD"; break;
+      }
+      std::clog << ") for " << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+   }
+   return false;
+}
diff --git a/apt-pkg/contrib/netrc.h b/apt-pkg/contrib/netrc.h
new file mode 100644
index 0000000..2d202d1
--- /dev/null
+++ b/apt-pkg/contrib/netrc.h
@@ -0,0 +1,30 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   netrc file parser - returns the login and password of a give host in
+                       a specified netrc-type file
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Originally written by Daniel Stenberg, <daniel@haxx.se>, et al. and
+   placed into the Public Domain, do with it what you will.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef NETRC_H
+#define NETRC_H
+
+#include <string>
+
+#include <apt-pkg/macros.h>
+
+
+
+class URI;
+class FileFd;
+
+APT_PUBLIC bool MaybeAddAuth(FileFd &NetRCFile, URI &Uri);
+#endif
diff --git a/apt-pkg/contrib/progress.cc b/apt-pkg/contrib/progress.cc
new file mode 100644
index 0000000..eb688b9
--- /dev/null
+++ b/apt-pkg/contrib/progress.cc
@@ -0,0 +1,229 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   OpProgress - Operation Progress
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/progress.h>
+
+#include <cmath>
+#include <chrono>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <stdio.h>
+#include <sys/time.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// OpProgress::OpProgress - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+OpProgress::OpProgress() : Current(0), Total(0), Size(0), SubTotal(1), 
+                           LastPercent(0), Percent(0)
+{
+   memset(&LastTime,0,sizeof(LastTime));
+}
+									/*}}}*/
+// OpProgress::Progress - Sub progress with no state change		/*{{{*/
+// ---------------------------------------------------------------------
+/* Current is the Base Overall progress in units of Total. Cur is the sub
+   progress in units of SubTotal. Size is a scaling factor that says what
+   percent of Total SubTotal is. */
+void OpProgress::Progress(unsigned long long Cur)
+{
+   if (Total == 0 || Size == 0 || SubTotal == 0)
+      Percent = 0;
+   else
+      Percent = (Current + Cur/((double)SubTotal)*Size)*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::OverallProgress - Set the overall progress		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpProgress::OverallProgress(unsigned long long Current, unsigned long long Total,
+	  			 unsigned long long Size,const string &Op)
+{
+   this->Current = Current;
+   this->Total = Total;
+   this->Size = Size;
+   this->Op = Op;
+   SubOp = string();
+   if (Total == 0)
+      Percent = 0;
+   else
+      Percent = Current*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::SubProgress - Set the sub progress state			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpProgress::SubProgress(unsigned long long SubTotal,const string &Op,
+			     float const Percent)
+{
+   this->SubTotal = SubTotal;
+   if (Op.empty() == false)
+      SubOp = Op;
+   if (Total == 0 || Percent == 0)
+      this->Percent = 0;
+   else if (Percent != -1)
+      this->Percent = this->Current += (Size*Percent)/SubTotal;
+   else
+      this->Percent = Current*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::CheckChange - See if the display should be updated	/*{{{*/
+// ---------------------------------------------------------------------
+/* Progress calls are made so frequently that if every one resulted in 
+   an update the display would be swamped and the system much slower.
+   This provides an upper bound on the update rate. */
+bool OpProgress::CheckChange(float Interval)
+{
+   // For absolute progress, we assume every call is relevant.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      return true;
+   // New major progress indication
+   if (Op != LastOp)
+   {
+      MajorChange = true;
+      LastOp = Op;
+      return true;
+   }
+   MajorChange = false;
+
+   if (SubOp != LastSubOp)
+   {
+      LastSubOp = SubOp;
+      return true;
+   }
+   
+   if (std::lround(LastPercent) == std::lround(Percent))
+      return false;
+
+   LastPercent = Percent;
+   
+   if (Interval == 0)
+      return false;
+   
+   // Check time delta
+   auto const Now = std::chrono::steady_clock::now().time_since_epoch();
+   auto const Now_sec = std::chrono::duration_cast<std::chrono::seconds>(Now);
+   auto const Now_usec = std::chrono::duration_cast<std::chrono::microseconds>(Now - Now_sec);
+   struct timeval NowTime = { static_cast<time_t>(Now_sec.count()), static_cast<suseconds_t>(Now_usec.count()) };
+
+   std::chrono::duration<decltype(Interval)> Delta =
+      std::chrono::seconds(NowTime.tv_sec - LastTime.tv_sec) +
+      std::chrono::microseconds(NowTime.tv_usec - LastTime.tv_usec);
+
+   if (Delta.count() < Interval)
+      return false;
+   LastTime = NowTime;
+   return true;
+}
+									/*}}}*/
+// OpTextProgress::OpTextProgress - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+OpTextProgress::OpTextProgress(Configuration &Config) :
+                               NoUpdate(false), NoDisplay(false), LastLen(0)
+{
+   if (Config.FindI("quiet",0) >= 1 || Config.FindB("quiet::NoUpdate", false) == true)
+      NoUpdate = true;
+   if (Config.FindI("quiet",0) >= 2 || Config.FindB("quiet::NoProgress", false) == true)
+      NoDisplay = true;
+}
+									/*}}}*/
+// OpTextProgress::Done - Clean up the display				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpTextProgress::Done()
+{
+   if (NoUpdate == false && OldOp.empty() == false)
+   {
+      char S[300];
+      if (_error->PendingError() == true)
+	 snprintf(S,sizeof(S),_("%c%s... Error!"),'\r',OldOp.c_str());
+      else
+	 snprintf(S,sizeof(S),_("%c%s... Done"),'\r',OldOp.c_str());
+      Write(S);
+      cout << endl;
+      OldOp = string();
+   }
+
+   if (NoUpdate == true && NoDisplay == false && OldOp.empty() == false)
+   {
+      OldOp = string();
+      cout << endl;
+   }
+}
+									/*}}}*/
+// OpTextProgress::Update - Simple text spinner				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpTextProgress::Update()
+{
+   if (CheckChange((NoUpdate == true?0:0.7)) == false)
+      return;
+   
+   // No percent spinner
+   if (NoUpdate == true)
+   {
+      if (MajorChange == false)
+	 return;
+      if (NoDisplay == false)
+      {
+	 if (OldOp.empty() == false)
+	    cout << endl;
+	 OldOp = "a";
+	 cout << Op << _("...") << flush;
+      }
+      
+      return;
+   }
+
+   // Erase the old text and 'log' the event
+   char S[300];
+   if (MajorChange == true && OldOp.empty() == false)
+   {
+      snprintf(S,sizeof(S),"\r%s",OldOp.c_str());
+      Write(S);
+      cout << endl;
+   }
+
+   // Print the spinner. Absolute progress shows us a time progress.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false) && Total != -1llu)
+      snprintf(S, sizeof(S), _("%c%s... %llu/%llus"), '\r', Op.c_str(), Current, Total);
+   else if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      snprintf(S, sizeof(S), _("%c%s... %llus"), '\r', Op.c_str(), Current);
+   else
+      snprintf(S, sizeof(S), _("%c%s... %u%%"), '\r', Op.c_str(), (unsigned int)Percent);
+   Write(S);
+
+   OldOp = Op;
+}
+									/*}}}*/
+// OpTextProgress::Write - Write the progress string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This space fills the end to overwrite the previous text */
+void OpTextProgress::Write(const char *S)
+{
+   cout << S;
+   for (unsigned int I = strlen(S); I < LastLen; I++)
+      cout << ' ';
+   cout << '\r' << flush;
+   LastLen = strlen(S);
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/progress.h b/apt-pkg/contrib/progress.h
new file mode 100644
index 0000000..d6a698a
--- /dev/null
+++ b/apt-pkg/contrib/progress.h
@@ -0,0 +1,87 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   OpProgress - Operation Progress
+   
+   This class allows lengthy operations to communicate their progress 
+   to the GUI. The progress model is simple and is not designed to handle
+   the complex case of the multi-activity acquire class.
+   
+   The model is based on the concept of an overall operation consisting
+   of a series of small sub operations. Each sub operation has it's own
+   completion status and the overall operation has it's completion status.
+   The units of the two are not mixed and are completely independent.
+   
+   The UI is expected to subclass this to provide the visuals to the user.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PROGRESS_H
+#define PKGLIB_PROGRESS_H
+
+#include <apt-pkg/macros.h>
+#include <string>
+#include <sys/time.h>
+
+
+class Configuration;
+class APT_PUBLIC OpProgress
+{
+   friend class OpTextProgress;
+   unsigned long long Current;
+   unsigned long long Total;
+   unsigned long long Size;
+   unsigned long long SubTotal;
+   float LastPercent;
+   
+   // Change reduction code
+   struct timeval LastTime;
+   std::string LastOp;
+   std::string LastSubOp;
+   
+   protected:
+   
+   std::string Op;
+   std::string SubOp;
+   float Percent;
+   
+   bool MajorChange;
+   
+   bool CheckChange(float Interval = 0.7);		    
+   virtual void Update() {};
+   
+   public:
+   
+   void Progress(unsigned long long Current);
+   void SubProgress(unsigned long long SubTotal, const std::string &Op = "", float const Percent = -1);
+   void OverallProgress(unsigned long long Current,unsigned long long Total,
+			unsigned long long Size,const std::string &Op);
+   virtual void Done() {};
+   
+   OpProgress();
+   virtual ~OpProgress() {};
+};
+
+class APT_PUBLIC OpTextProgress : public OpProgress
+{
+   protected:
+
+   std::string OldOp;
+   bool NoUpdate;
+   bool NoDisplay;
+   unsigned long LastLen;
+   virtual void Update() APT_OVERRIDE;
+   void Write(const char *S);
+   
+   public:
+
+   virtual void Done() APT_OVERRIDE;
+   
+   explicit OpTextProgress(bool NoUpdate = false) : NoUpdate(NoUpdate),
+                NoDisplay(false), LastLen(0) {};
+   explicit OpTextProgress(Configuration &Config);
+   virtual ~OpTextProgress() {Done();};
+};
+
+#endif
diff --git a/apt-pkg/contrib/proxy.cc b/apt-pkg/contrib/proxy.cc
new file mode 100644
index 0000000..a99f44f
--- /dev/null
+++ b/apt-pkg/contrib/proxy.cc
@@ -0,0 +1,99 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Proxy - Proxy related functions
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "proxy.h"
+									/*}}}*/
+
+// AutoDetectProxy - auto detect proxy					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+static std::vector<std::string> CompatibleProxies(URI const &URL)
+{
+   if (URL.Access == "http" || URL.Access == "https")
+      return {"http", "https", "socks5h"};
+   return {URL.Access};
+}
+
+bool AutoDetectProxy(URI &URL)
+{
+   // we support both http/https debug options
+   bool Debug = _config->FindB("Debug::Acquire::"+URL.Access,false);
+
+   // the user already explicitly set a proxy for this host
+   if(_config->Find("Acquire::"+URL.Access+"::proxy::"+URL.Host, "") != "")
+      return true;
+
+   // option is "Acquire::http::Proxy-Auto-Detect" but we allow the old
+   // name without the dash ("-")
+   std::string AutoDetectProxyCmd = _config->Find("Acquire::"+URL.Access+"::Proxy-Auto-Detect",
+                                      _config->Find("Acquire::"+URL.Access+"::ProxyAutoDetect"));
+
+   if (AutoDetectProxyCmd.empty())
+      return true;
+
+   if (Debug)
+      std::clog << "Using auto proxy detect command: " << AutoDetectProxyCmd << std::endl;
+
+   if (faccessat(AT_FDCWD, AutoDetectProxyCmd.c_str(), R_OK | X_OK, AT_EACCESS) != 0)
+      return _error->Errno("access", "ProxyAutoDetect command '%s' can not be executed!", AutoDetectProxyCmd.c_str());
+
+   std::string const urlstring = URL;
+   std::vector<const char *> Args;
+   Args.push_back(AutoDetectProxyCmd.c_str());
+   Args.push_back(urlstring.c_str());
+   Args.push_back(nullptr);
+   FileFd PipeFd;
+   pid_t Child;
+   if (Popen(&Args[0], PipeFd, Child, FileFd::ReadOnly, false, true) == false)
+      return _error->Error("ProxyAutoDetect command '%s' failed!", AutoDetectProxyCmd.c_str());
+   char buf[512];
+   bool const goodread = PipeFd.ReadLine(buf, sizeof(buf)) != nullptr;
+   PipeFd.Close();
+   if (ExecWait(Child, "ProxyAutoDetect") == false)
+      return false;
+   // no output means the detector has no idea which proxy to use
+   // and apt will use the generic proxy settings
+   if (goodread == false)
+      return true;
+   auto const cleanedbuf = _strstrip(buf);
+   // We warn about this as the implementor probably meant to use DIRECT instead
+   if (cleanedbuf[0] == '\0')
+   {
+      _error->Warning("ProxyAutoDetect command returned an empty line");
+      return true;
+   }
+
+   if (Debug)
+      std::clog << "auto detect command returned: '" << cleanedbuf << "'" << std::endl;
+
+   auto compatibleTypes = CompatibleProxies(URL);
+   bool compatible = strcmp(cleanedbuf, "DIRECT") == 0 ||
+		     compatibleTypes.end() != std::find_if(compatibleTypes.begin(),
+							   compatibleTypes.end(), [cleanedbuf](std::string &compat) {
+							      return strstr(cleanedbuf, compat.c_str()) == cleanedbuf;
+							   });
+
+   if (compatible)
+      _config->Set("Acquire::"+URL.Access+"::proxy::"+URL.Host, cleanedbuf);
+
+   return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/proxy.h b/apt-pkg/contrib/proxy.h
new file mode 100644
index 0000000..f6d70ea
--- /dev/null
+++ b/apt-pkg/contrib/proxy.h
@@ -0,0 +1,16 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Proxy - Proxy operations
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PROXY_H
+#define PKGLIB_PROXY_H
+
+class URI;
+APT_PUBLIC bool AutoDetectProxy(URI &URL);
+
+
+#endif
diff --git a/apt-pkg/contrib/srvrec.cc b/apt-pkg/contrib/srvrec.cc
new file mode 100644
index 0000000..3eb5f1d
--- /dev/null
+++ b/apt-pkg/contrib/srvrec.cc
@@ -0,0 +1,211 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   SRV record support
+
+   ##################################################################### */
+									/*}}}*/
+#include <config.h>
+
+#include <netdb.h>
+
+#include <arpa/nameser.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <resolv.h>
+#include <time.h>
+
+#include <algorithm>
+#include <memory>
+#include <tuple>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/strutl.h>
+
+#include "srvrec.h"
+
+bool SrvRec::operator==(SrvRec const &other) const
+{
+   return (std::tie(target, priority, weight, port) ==
+           std::tie(other.target, other.priority, other.weight, other.port));
+}
+
+bool GetSrvRecords(std::string host, int port, std::vector<SrvRec> &Result)
+{
+   // try SRV only for hostnames, not for IP addresses
+   {
+      struct in_addr addr4;
+      struct in6_addr addr6;
+      if (inet_pton(AF_INET, host.c_str(), &addr4) == 1 ||
+	  inet_pton(AF_INET6, host.c_str(), &addr6) == 1)
+	 return true;
+   }
+
+   std::string target;
+   int res;
+   struct servent s_ent_buf;
+   struct servent *s_ent = nullptr;
+   std::vector<char> buf(1024);
+
+   res = getservbyport_r(htons(port), "tcp", &s_ent_buf, buf.data(), buf.size(), &s_ent);
+   if (res != 0 || s_ent == nullptr)
+      return false;
+
+   strprintf(target, "_%s._tcp.%s", s_ent->s_name, host.c_str());
+   return GetSrvRecords(target, Result);
+}
+
+bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result)
+{
+   unsigned char answer[PACKETSZ];
+   int answer_len, compressed_name_len;
+   int answer_count;
+#if __RES >= 19991006
+   struct __res_state res;
+
+   if (res_ninit(&res) != 0)
+      return _error->Errno("res_init", "Failed to init resolver");
+
+   // Close on return
+   std::shared_ptr<void> guard(&res, res_nclose);
+
+   answer_len = res_nquery(&res, name.c_str(), C_IN, T_SRV, answer, sizeof(answer));
+#else
+   if (res_init() != 0)
+      return _error->Errno("res_init", "Failed to init resolver");
+
+   answer_len = res_query(name.c_str(), C_IN, T_SRV, answer, sizeof(answer));
+#endif //__RES >= 19991006
+   if (answer_len == -1)
+      return false;
+   if (answer_len < (int)sizeof(HEADER))
+      return _error->Warning("Not enough data from res_query (%i)", answer_len);
+
+   // check the header
+   HEADER *header = (HEADER*)answer;
+   if (header->rcode != NOERROR)
+      return _error->Warning("res_query returned rcode %i", header->rcode);
+   answer_count = ntohs(header->ancount);
+   if (answer_count <= 0)
+      return _error->Warning("res_query returned no answers (%i) ", answer_count);
+
+   // skip the header
+   compressed_name_len = dn_skipname(answer+sizeof(HEADER), answer+answer_len);
+   if(compressed_name_len < 0)
+      return _error->Warning("dn_skipname failed %i", compressed_name_len);
+
+   // pt points to the first answer record, go over all of them now
+   unsigned char *pt = answer+sizeof(HEADER)+compressed_name_len+QFIXEDSZ;
+   while ((int)Result.size() < answer_count && pt < answer+answer_len)
+   {
+      u_int16_t type, klass, priority, weight, port, dlen;
+      char buf[MAXDNAME];
+
+      compressed_name_len = dn_skipname(pt, answer+answer_len);
+      if (compressed_name_len < 0)
+         return _error->Warning("dn_skipname failed (2): %i",
+                                compressed_name_len);
+      pt += compressed_name_len;
+      if (((answer+answer_len) - pt) < 16)
+         return _error->Warning("packet too short");
+
+      // extract the data out of the result buffer
+      #define extract_u16(target, p) target = *p++ << 8; target |= *p++;
+
+      extract_u16(type, pt);
+      if(type != T_SRV)
+         return _error->Warning("Unexpected type excepted %x != %x",
+                                T_SRV, type);
+      extract_u16(klass, pt);
+      if(klass != C_IN)
+         return _error->Warning("Unexpected class excepted %x != %x",
+                                C_IN, klass);
+      pt += 4;  // ttl
+      extract_u16(dlen, pt);
+      extract_u16(priority, pt);
+      extract_u16(weight, pt);
+      extract_u16(port, pt);
+
+      #undef extract_u16
+
+      compressed_name_len = dn_expand(answer, answer+answer_len, pt, buf, sizeof(buf));
+      if(compressed_name_len < 0)
+         return _error->Warning("dn_expand failed %i", compressed_name_len);
+      pt += compressed_name_len;
+
+      // add it to our class
+      Result.emplace_back(buf, priority, weight, port);
+   }
+
+   // implement load balancing as specified in RFC-2782
+
+   // sort them by priority
+   std::stable_sort(Result.begin(), Result.end());
+
+   if (_config->FindB("Debug::Acquire::SrvRecs", false))
+      for(auto const &R : Result)
+	 std::cerr << "SrvRecs: got " << R.target
+		   << " prio: " << R.priority
+		   << " weight: " << R.weight
+		   << '\n';
+
+   return true;
+}
+
+SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs)
+{
+   // FIXME: instead of the simplistic shuffle below use the algorithm
+   //        described in rfc2782 (with weights)
+   //        and figure out how the weights need to be adjusted if
+   //        a host refuses connections
+
+#if 0  // all code below is only needed for the weight adjusted selection 
+   // assign random number ranges
+   int prev_weight = 0;
+   int prev_priority = 0;
+   for(std::vector<SrvRec>::iterator I = Result.begin();
+      I != Result.end(); ++I)
+   {
+      if(prev_priority != I->priority)
+         prev_weight = 0;
+      I->random_number_range_start = prev_weight;
+      I->random_number_range_end = prev_weight + I->weight;
+      prev_weight = I->random_number_range_end;
+      prev_priority = I->priority;
+
+      if (_config->FindB("Debug::Acquire::SrvRecs", false) == true)
+         std::cerr << "SrvRecs: got " << I->target
+                   << " prio: " << I->priority
+                   << " weight: " << I->weight
+                   << std::endl;
+   }
+
+   // go over the code in reverse order and note the max random range
+   int max = 0;
+   prev_priority = 0;
+   for(std::vector<SrvRec>::iterator I = Result.end();
+      I != Result.begin(); --I)
+   {
+      if(prev_priority != I->priority)
+         max = I->random_number_range_end;
+      I->random_number_range_max = max;
+   }
+#endif
+
+   // shuffle in a very simplistic way for now (equal weights)
+   std::vector<SrvRec>::iterator I = Recs.begin();
+   std::vector<SrvRec>::iterator const J = std::find_if(Recs.begin(), Recs.end(),
+	 [&I](SrvRec const &J) { return I->priority != J.priority; });
+
+   // clock seems random enough.
+   I += std::max(static_cast<clock_t>(0), clock()) % std::distance(I, J);
+   SrvRec const selected = std::move(*I);
+   Recs.erase(I);
+
+   if (_config->FindB("Debug::Acquire::SrvRecs", false) == true)
+      std::cerr << "PopFromSrvRecs: selecting " << selected.target << std::endl;
+
+   return selected;
+}
diff --git a/apt-pkg/contrib/srvrec.h b/apt-pkg/contrib/srvrec.h
new file mode 100644
index 0000000..1e981d3
--- /dev/null
+++ b/apt-pkg/contrib/srvrec.h
@@ -0,0 +1,57 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   SRV record support
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef SRVREC_H
+#define SRVREC_H
+
+#include <string>
+#include <vector>
+#include <arpa/nameser.h>
+#include <sys/types.h>
+
+#include <apt-pkg/macros.h>
+
+class APT_PUBLIC SrvRec
+{
+ public:
+   std::string target;
+   u_int16_t priority;
+   u_int16_t weight;
+   u_int16_t port;
+
+   // each server is assigned a interval [start, end] in the space of [0, max]
+   int random_number_range_start;
+   int random_number_range_end;
+   int random_number_range_max;
+
+   bool operator<(SrvRec const &other) const {
+      return this->priority < other.priority;
+   }
+   bool operator==(SrvRec const &other) const;
+
+   SrvRec(std::string const Target, u_int16_t const Priority,
+	 u_int16_t const Weight, u_int16_t const Port) :
+      target(Target), priority(Priority), weight(Weight), port(Port),
+      random_number_range_start(0), random_number_range_end(0),
+      random_number_range_max(0) {}
+};
+
+/** \brief Get SRV records from host/port (builds the query string internally) 
+ */
+APT_PUBLIC bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result);
+
+/** \brief Get SRV records for query string like: _http._tcp.example.com
+ */
+APT_PUBLIC bool GetSrvRecords(std::string host, int port, std::vector<SrvRec> &Result);
+
+/** \brief Pop a single SRV record from the vector of SrvRec taking
+ *         priority and weight into account
+ */
+APT_PUBLIC SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs);
+
+#endif
diff --git a/apt-pkg/contrib/string_view.h b/apt-pkg/contrib/string_view.h
new file mode 100644
index 0000000..04f6ff1
--- /dev/null
+++ b/apt-pkg/contrib/string_view.h
@@ -0,0 +1,163 @@
+/*
+ * Basic implementation of string_view
+ *
+ * (C) 2015 Julian Andres Klode <jak@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#if !defined(APT_STRINGVIEW_H)
+#define APT_STRINGVIEW_H
+#include <apt-pkg/macros.h>
+#include <string>
+#include <string.h>
+
+namespace APT {
+
+/**
+ * \brief Simple subset of std::string_view from C++17
+ *
+ * This is an internal implementation of the subset of std::string_view
+ * used by APT. It is not meant to be used in programs, only inside the
+ * library for performance critical paths.
+ */
+class StringView {
+    const char *data_;
+    size_t size_;
+
+public:
+    static constexpr size_t npos = static_cast<size_t>(-1);
+    static_assert(APT::StringView::npos == std::string::npos, "npos values are different");
+
+    /* Constructors */
+    constexpr StringView() : data_(""), size_(0) {}
+    constexpr StringView(const char *data, size_t size) : data_(data), size_(size) {}
+
+    StringView(const char *data) : data_(data), size_(strlen(data)) {}
+    StringView(std::string const & str): data_(str.data()), size_(str.size()) {}
+
+    /* Modifiers */
+    void remove_prefix(size_t n) { data_ += n; size_ -= n; }
+    void remove_suffix(size_t n) { size_ -= n; }
+    void clear() { size_ = 0; }
+
+    /* Viewers */
+    constexpr StringView substr(size_t pos, size_t n = npos) const {
+        return StringView(data_ + pos, n > (size_ - pos) ? (size_ - pos) : n);
+    }
+
+    size_t find(int c, size_t pos) const {
+       if (pos == 0)
+	  return find(c);
+       size_t const found = substr(pos).find(c);
+       if (found == npos)
+	  return npos;
+       return pos + found;
+    }
+    size_t find(int c) const {
+        const char *found = static_cast<const char*>(memchr(data_, c, size_));
+
+        if (found == NULL)
+            return npos;
+
+        return found - data_;
+    }
+
+    size_t rfind(int c, size_t pos) const {
+       if (pos == npos)
+	  return rfind(c);
+       return APT::StringView(data_, pos).rfind(c);
+    }
+    size_t rfind(int c) const {
+        const char *found = static_cast<const char*>(memrchr(data_, c, size_));
+
+        if (found == NULL)
+            return npos;
+
+        return found - data_;
+    }
+
+    size_t find(APT::StringView const needle) const {
+       if (needle.empty())
+	  return npos;
+       if (needle.length() == 1)
+	  return find(*needle.data());
+       size_t found = 0;
+       while ((found = find(*needle.data(), found)) != npos) {
+	  if (compare(found, needle.length(), needle) == 0)
+	     return found;
+	  ++found;
+       }
+       return found;
+    }
+    size_t find(APT::StringView const needle, size_t pos) const {
+       if (pos == 0)
+	  return find(needle);
+       size_t const found = substr(pos).find(needle);
+       if (found == npos)
+	  return npos;
+       return pos + found;
+    }
+
+    /* Conversions */
+    std::string to_string() const {
+        return std::string(data_, size_);
+    }
+
+    /* Comparisons */
+    int compare(size_t pos, size_t n, StringView other) const {
+        return substr(pos, n).compare(other);
+    }
+
+    int compare(StringView other) const {
+        int res;
+
+        res = memcmp(data_, other.data_, std::min(size_, other.size_));
+        if (res != 0)
+            return res;
+        if (size_ == other.size_)
+            return res;
+
+        return (size_ > other.size_) ? 1 : -1;
+    }
+
+    /* Optimization: If size not equal, string cannot be equal */
+    bool operator ==(StringView other) const { return size_ == other.size_ && compare(other) == 0; }
+    bool operator !=(StringView other) const { return !(*this == other); }
+
+    /* Accessors */
+    constexpr bool empty() const { return size_ == 0; }
+    constexpr const char* data() const { return data_; }
+    constexpr const char* begin() const { return data_; }
+    constexpr const char* end() const { return data_ + size_; }
+    constexpr char operator [](size_t i) const { return data_[i]; }
+    constexpr size_t size() const { return size_; }
+    constexpr size_t length() const { return size_; }
+};
+
+/**
+ * \brief Faster comparison for string views (compare size before data)
+ *
+ * Still stable, but faster than the normal ordering. */
+static inline int StringViewCompareFast(StringView a, StringView b) {
+    if (a.size() != b.size())
+        return a.size() - b.size();
+
+    return memcmp(a.data(), b.data(), a.size());
+}
+
+static constexpr inline APT::StringView operator""_sv(const char *data, size_t size)
+{
+   return APT::StringView(data, size);
+}
+}
+
+inline bool operator ==(const char *other, APT::StringView that);
+inline bool operator ==(const char *other, APT::StringView that) { return that.operator==(other); }
+inline bool operator ==(std::string const &other, APT::StringView that);
+inline bool operator ==(std::string const &other, APT::StringView that) { return that.operator==(other); }
+
+#endif
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
new file mode 100644
index 0000000..67100f1
--- /dev/null
+++ b/apt-pkg/contrib/strutl.cc
@@ -0,0 +1,1820 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   String Util - Some useful string functions.
+
+   These have been collected from here and there to do all sorts of useful
+   things to strings. They are useful in file parsers, URI handlers and
+   especially in APT methods.   
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@gpu.srv.ualberta.ca>
+   
+   ##################################################################### */
+									/*}}}*/
+// Includes								/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <array>
+#include <iomanip>
+#include <limits>
+#include <locale>
+#include <sstream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <ctype.h>
+#include <errno.h>
+#include <iconv.h>
+#include <regex.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+// Strip - Remove white space from the front and back of a string       /*{{{*/
+// ---------------------------------------------------------------------
+namespace APT {
+   namespace String {
+std::string Strip(const std::string &str)
+{
+   // ensure we have at least one character
+   if (str.empty() == true)
+      return str;
+
+   char const * const s = str.c_str();
+   size_t start = 0;
+   for (; isspace(s[start]) != 0; ++start)
+      ; // find the first not-space
+
+   // string contains only whitespaces
+   if (s[start] == '\0')
+      return "";
+
+   size_t end = str.length() - 1;
+   for (; isspace(s[end]) != 0; --end)
+      ; // find the last not-space
+
+   return str.substr(start, end - start + 1);
+}
+
+bool Endswith(const std::string &s, const std::string &end)
+{
+   if (end.size() > s.size())
+      return false;
+   return (s.compare(s.size() - end.size(), end.size(), end) == 0);
+}
+
+bool Startswith(const std::string &s, const std::string &start)
+{
+   if (start.size() > s.size())
+      return false;
+   return (s.compare(0, start.size(), start) == 0);
+}
+
+std::string Join(std::vector<std::string> list, const std::string &sep)
+{
+   std::ostringstream oss;
+   for (auto it = list.begin(); it != list.end(); it++)
+   {
+      if (it != list.begin()) oss << sep;
+      oss << *it;
+   }
+   return oss.str();
+}
+
+// Returns string display length honoring multi-byte characters
+size_t DisplayLength(StringView str)
+{
+   size_t len = 0;
+
+   const char *p = str.data();
+   const char *const end = str.end();
+
+   mbstate_t state{};
+   while (p < end)
+   {
+      wchar_t wch;
+      size_t res = mbrtowc(&wch, p, end - p, &state);
+      switch (res)
+      {
+      case 0:
+         // Null wide character (i.e. L'\0') - stop
+         p = end;
+         break;
+
+      case static_cast<size_t>(-1):
+         // Byte sequence is invalid. Assume that it's
+         // a single-byte single-width character.
+         len += 1;
+         p += 1;
+
+         // state is undefined in this case - reset it
+         state = {};
+
+         break;
+
+      case static_cast<size_t>(-2):
+         // Byte sequence is too short. Assume that it's
+         // an incomplete single-width character and stop.
+         len += 1;
+         p = end;
+         break;
+
+      default:
+         len += wcwidth(wch);
+         p += res;
+      }
+   }
+
+   return len;
+}
+
+}
+}
+									/*}}}*/
+// UTF8ToCodeset - Convert some UTF-8 string for some codeset   	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is handy to use before display some information for enduser  */
+bool UTF8ToCodeset(const char *codeset, const string &orig, string *dest)
+{
+  iconv_t cd;
+  const char *inbuf;
+  char *inptr, *outbuf;
+  size_t insize, bufsize;
+  dest->clear();
+
+  cd = iconv_open(codeset, "UTF-8");
+  if (cd == (iconv_t)(-1)) {
+     // Something went wrong
+     if (errno == EINVAL)
+	_error->Error("conversion from 'UTF-8' to '%s' not available",
+               codeset);
+     else
+	perror("iconv_open");
+     
+     return false;
+  }
+
+  insize = bufsize = orig.size();
+  inbuf = orig.data();
+  inptr = (char *)inbuf;
+  outbuf = new char[bufsize];
+  size_t lastError = -1;
+
+  while (insize != 0)
+  {
+     char *outptr = outbuf;
+     size_t outsize = bufsize;
+     size_t const err = iconv(cd, &inptr, &insize, &outptr, &outsize);
+     dest->append(outbuf, outptr - outbuf);
+     if (err == (size_t)(-1))
+     {
+	switch (errno)
+	{
+	case EILSEQ:
+	   insize--;
+	   inptr++;
+	   // replace a series of unknown multibytes with a single "?"
+	   if (lastError != insize) {
+	      lastError = insize - 1;
+	      dest->append("?");
+	   }
+	   break;
+	case EINVAL:
+	   insize = 0;
+	   break;
+	case E2BIG:
+	   if (outptr == outbuf)
+	   {
+	      bufsize *= 2;
+	      delete[] outbuf;
+	      outbuf = new char[bufsize];
+	   }
+	   break;
+	}
+     }
+  }
+
+  delete[] outbuf;
+  
+  iconv_close(cd);
+
+  return true;
+}
+									/*}}}*/
+// strstrip - Remove white space from the front and back of a string	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is handy to use when parsing a file. It also removes \n's left 
+   over from fgets and company */
+char *_strstrip(char *String)
+{
+   for (;*String != 0 && (*String == ' ' || *String == '\t'); String++);
+
+   if (*String == 0)
+      return String;
+   return _strrstrip(String);
+}
+									/*}}}*/
+// strrstrip - Remove white space from the back of a string	/*{{{*/
+// ---------------------------------------------------------------------
+char *_strrstrip(char *String)
+{
+   char *End = String + strlen(String) - 1;
+   for (;End != String - 1 && (*End == ' ' || *End == '\t' || *End == '\n' ||
+			       *End == '\r'); End--);
+   End++;
+   *End = 0;
+   return String;
+}
+									/*}}}*/
+// strtabexpand - Converts tabs into 8 spaces				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+char *_strtabexpand(char *String,size_t Len)
+{
+   for (char *I = String; I != I + Len && *I != 0; I++)
+   {
+      if (*I != '\t')
+	 continue;
+      if (I + 8 > String + Len)
+      {
+	 *I = 0;
+	 return String;
+      }
+
+      /* Assume the start of the string is 0 and find the next 8 char
+         division */
+      int Len;
+      if (String == I)
+	 Len = 1;
+      else
+	 Len = 8 - ((String - I) % 8);
+      Len -= 2;
+      if (Len <= 0)
+      {
+	 *I = ' ';
+	 continue;
+      }
+      
+      memmove(I + Len,I + 1,strlen(I) + 1);
+      for (char *J = I; J + Len != I; *I = ' ', I++);
+   }
+   return String;
+}
+									/*}}}*/
+// ParseQuoteWord - Parse a single word out of a string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This grabs a single word, converts any % escaped characters to their
+   proper values and advances the pointer. Double quotes are understood
+   and striped out as well. This is for URI/URL parsing. It also can 
+   understand [] brackets.*/
+bool ParseQuoteWord(const char *&String,string &Res)
+{
+   // Skip leading whitespace
+   const char *C = String;
+   for (; *C == ' '; C++)
+      ;
+   if (*C == 0)
+      return false;
+   
+   // Jump to the next word
+   for (;*C != 0 && isspace(*C) == 0; C++)
+   {
+      if (*C == '"')
+      {
+	 C = strchr(C + 1, '"');
+	 if (C == NULL)
+	    return false;
+      }
+      if (*C == '[')
+      {
+	 C = strchr(C + 1, ']');
+	 if (C == NULL)
+	    return false;
+      }
+   }
+
+   // Now de-quote characters
+   Res.clear();
+   Res.reserve(C - String);
+   char Tmp[3];
+   const char *Start = String;
+   while (Start != C)
+   {
+      if (*Start == '%' && Start + 2 < C &&
+	  isxdigit(Start[1]) && isxdigit(Start[2]))
+      {
+	 Tmp[0] = Start[1];
+	 Tmp[1] = Start[2];
+	 Tmp[2] = 0;
+	 Res.push_back(static_cast<char>(strtol(Tmp, 0, 16)));
+	 Start += 3;
+	 continue;
+      }
+      if (*Start != '"')
+	 Res.push_back(*Start);
+      ++Start;
+   }
+
+   // Skip ending white space
+   for (; isspace(*C) != 0; C++)
+      ;
+   String = C;
+   return true;
+}
+									/*}}}*/
+// ParseCWord - Parses a string like a C "" expression			/*{{{*/
+// ---------------------------------------------------------------------
+/* This expects a series of space separated strings enclosed in ""'s. 
+   It concatenates the ""'s into a single string. */
+bool ParseCWord(const char *&String,string &Res)
+{
+   // Skip leading whitespace
+   const char *C = String;
+   for (; *C == ' '; C++)
+      ;
+   if (*C == 0)
+      return false;
+
+   Res.clear();
+   Res.reserve(strlen(String));
+   for (; *C != 0; ++C)
+   {
+      if (*C == '"')
+      {
+	 for (C++; *C != 0 && *C != '"'; C++)
+	    Res.push_back(*C);
+
+	 if (*C == 0)
+	    return false;
+
+	 continue;
+      }
+
+      if (C != String && isspace(*C) != 0 && isspace(C[-1]) != 0)
+	 continue;
+      if (isspace(*C) == 0)
+	 return false;
+      Res.push_back(' ');
+   }
+   String = C;
+   return true;
+}
+									/*}}}*/
+// QuoteString - Convert a string into quoted from			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string QuoteString(const string &Str, const char *Bad)
+{
+   std::stringstream Res;
+   for (string::const_iterator I = Str.begin(); I != Str.end(); ++I)
+   {
+      if (strchr(Bad,*I) != 0 || isprint(*I) == 0 ||
+	  *I == 0x25 || // percent '%' char
+	  *I <= 0x20 || *I >= 0x7F) // control chars
+      {
+	 ioprintf(Res, "%%%02hhx", *I);
+      }
+      else
+	 Res << *I;
+   }
+   return Res.str();
+}
+									/*}}}*/
+// DeQuoteString - Convert a string from quoted from                    /*{{{*/
+// ---------------------------------------------------------------------
+/* This undoes QuoteString */
+string DeQuoteString(const string &Str)
+{
+   return DeQuoteString(Str.begin(),Str.end());
+}
+string DeQuoteString(string::const_iterator const &begin,
+			string::const_iterator const &end)
+{
+   string Res;
+   for (string::const_iterator I = begin; I != end; ++I)
+   {
+      if (*I == '%' && I + 2 < end &&
+	  isxdigit(I[1]) && isxdigit(I[2]))
+      {
+	 char Tmp[3];
+	 Tmp[0] = I[1];
+	 Tmp[1] = I[2];
+	 Tmp[2] = 0;
+	 Res += (char)strtol(Tmp,0,16);
+	 I += 2;
+	 continue;
+      }
+      else
+	 Res += *I;
+   }
+   return Res;   
+}
+
+                                                                        /*}}}*/
+// SizeToStr - Convert a long into a human readable size		/*{{{*/
+// ---------------------------------------------------------------------
+/* A max of 4 digits are shown before conversion to the next highest unit. 
+   The max length of the string will be 5 chars unless the size is > 10
+   YottaBytes (E24) */
+string SizeToStr(double Size)
+{
+   double ASize;
+   if (Size >= 0)
+      ASize = Size;
+   else
+      ASize = -1*Size;
+
+   /* bytes, KiloBytes, MegaBytes, GigaBytes, TeraBytes, PetaBytes, 
+      ExaBytes, ZettaBytes, YottaBytes */
+   char Ext[] = {'\0','k','M','G','T','P','E','Z','Y'};
+   int I = 0;
+   while (I <= 8)
+   {
+      if (ASize < 100 && I != 0)
+      {
+	 std::string S;
+	 strprintf(S, "%'.1f %c", ASize, Ext[I]);
+	 return S;
+      }
+
+      if (ASize < 10000)
+      {
+	 std::string S;
+	 strprintf(S, "%'.0f %c", ASize, Ext[I]);
+	 return S;
+      }
+      ASize /= 1000.0;
+      I++;
+   }
+   return "";
+}
+									/*}}}*/
+// TimeToStr - Convert the time into a string				/*{{{*/
+// ---------------------------------------------------------------------
+/* Converts a number of seconds to a hms format */
+string TimeToStr(unsigned long Sec)
+{
+   std::string S;
+   if (Sec > 60*60*24)
+   {
+      //TRANSLATOR: d means days, h means hours, min means minutes, s means seconds
+      strprintf(S,_("%lid %lih %limin %lis"),Sec/60/60/24,(Sec/60/60) % 24,(Sec/60) % 60,Sec % 60);
+   }
+   else if (Sec > 60*60)
+   {
+      //TRANSLATOR: h means hours, min means minutes, s means seconds
+      strprintf(S,_("%lih %limin %lis"),Sec/60/60,(Sec/60) % 60,Sec % 60);
+   }
+   else if (Sec > 60)
+   {
+      //TRANSLATOR: min means minutes, s means seconds
+      strprintf(S,_("%limin %lis"),Sec/60,Sec % 60);
+   }
+   else
+   {
+      //TRANSLATOR: s means seconds
+      strprintf(S,_("%lis"),Sec);
+   }
+   return S;
+}
+									/*}}}*/
+// SubstVar - Substitute a string for another string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This replaces all occurrences of Subst with Contents in Str. */
+string SubstVar(const string &Str,const string &Subst,const string &Contents)
+{
+   if (Subst.empty() == true)
+      return Str;
+
+   string::size_type Pos = 0;
+   string::size_type OldPos = 0;
+   string Temp;
+
+   while (OldPos < Str.length() &&
+	  (Pos = Str.find(Subst,OldPos)) != string::npos)
+   {
+      if (OldPos != Pos)
+	 Temp.append(Str, OldPos, Pos - OldPos);
+      if (Contents.empty() == false)
+	 Temp.append(Contents);
+      OldPos = Pos + Subst.length();
+   }
+
+   if (OldPos == 0)
+      return Str;
+
+   if (OldPos >= Str.length())
+      return Temp;
+
+   Temp.append(Str, OldPos, string::npos);
+   return Temp;
+}
+string SubstVar(string Str,const struct SubstVar *Vars)
+{
+   for (; Vars->Subst != 0; Vars++)
+      Str = SubstVar(Str,Vars->Subst,*Vars->Contents);
+   return Str;
+}
+									/*}}}*/
+// OutputInDepth - return a string with separator multiplied with depth /*{{{*/
+// ---------------------------------------------------------------------
+/* Returns a string with the supplied separator depth + 1 times in it */
+std::string OutputInDepth(const unsigned long Depth, const char* Separator)
+{
+   std::string output = "";
+   for(unsigned long d=Depth+1; d > 0; d--)
+      output.append(Separator);
+   return output;
+}
+									/*}}}*/
+// URItoFileName - Convert the uri into a unique file name		/*{{{*/
+// ---------------------------------------------------------------------
+/* This converts a URI into a safe filename. It quotes all unsafe characters
+   and converts / to _ and removes the scheme identifier. The resulting
+   file name should be unique and never occur again for a different file */
+string URItoFileName(const string &URI)
+{
+   // Nuke 'sensitive' items
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   U.Access.clear();
+   
+   // "\x00-\x20{}|\\\\^\\[\\]<>\"\x7F-\xFF";
+   string NewURI = QuoteString(U,"\\|{}[]<>\"^~_=!@#$%^&*");
+   replace(NewURI.begin(),NewURI.end(),'/','_');
+   return NewURI;
+}
+									/*}}}*/
+// Base64Encode - Base64 Encoding routine for short strings		/*{{{*/
+// ---------------------------------------------------------------------
+/* This routine performs a base64 transformation on a string. It was ripped
+   from wget and then patched and bug fixed.
+ 
+   This spec can be found in rfc2045 */
+string Base64Encode(const string &S)
+{
+   // Conversion table.
+   static char tbl[64] = {'A','B','C','D','E','F','G','H',
+   			  'I','J','K','L','M','N','O','P',
+                          'Q','R','S','T','U','V','W','X',
+                          'Y','Z','a','b','c','d','e','f',
+                          'g','h','i','j','k','l','m','n',
+                          'o','p','q','r','s','t','u','v',
+                          'w','x','y','z','0','1','2','3',
+                          '4','5','6','7','8','9','+','/'};
+   
+   // Pre-allocate some space
+   string Final;
+   Final.reserve((4*S.length() + 2)/3 + 2);
+
+   /* Transform the 3x8 bits to 4x6 bits, as required by
+      base64.  */
+   for (string::const_iterator I = S.begin(); I < S.end(); I += 3)
+   {
+      uint8_t Bits[3] = {0,0,0};
+      Bits[0] = I[0];
+      if (I + 1 < S.end())
+	 Bits[1] = I[1];
+      if (I + 2 < S.end())
+	 Bits[2] = I[2];
+
+      Final += tbl[Bits[0] >> 2];
+      Final += tbl[((Bits[0] & 3) << 4) + (Bits[1] >> 4)];
+      
+      if (I + 1 >= S.end())
+	 break;
+      
+      Final += tbl[((Bits[1] & 0xf) << 2) + (Bits[2] >> 6)];
+      
+      if (I + 2 >= S.end())
+	 break;
+      
+      Final += tbl[Bits[2] & 0x3f];
+   }
+
+   /* Apply the padding elements, this tells how many bytes the remote
+      end should discard */
+   if (S.length() % 3 == 2)
+      Final += '=';
+   if (S.length() % 3 == 1)
+      Final += "==";
+   
+   return Final;
+}
+									/*}}}*/
+// stringcmp - Arbitrary string compare					/*{{{*/
+// ---------------------------------------------------------------------
+/* This safely compares two non-null terminated strings of arbitrary 
+   length */
+int stringcmp(const char *A,const char *AEnd,const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+
+#if __GNUC__ >= 3
+int stringcmp(string::const_iterator A,string::const_iterator AEnd,
+	      const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+int stringcmp(string::const_iterator A,string::const_iterator AEnd,
+	      string::const_iterator B,string::const_iterator BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+#endif
+									/*}}}*/
+// stringcasecmp - Arbitrary case insensitive string compare		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+int stringcasecmp(const char *A,const char *AEnd,const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+#if __GNUC__ >= 3
+int stringcasecmp(string::const_iterator A,string::const_iterator AEnd,
+		  const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+int stringcasecmp(string::const_iterator A,string::const_iterator AEnd,
+		  string::const_iterator B,string::const_iterator BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+#endif
+									/*}}}*/
+// LookupTag - Lookup the value of a tag in a tagged string		/*{{{*/
+// ---------------------------------------------------------------------
+/* The format is like those used in package files and the method
+   communication system */
+std::string LookupTag(const std::string &Message, const char *TagC, const char *Default)
+{
+   std::string tag = std::string("\n") + TagC + ":";
+   if (Default == nullptr)
+      Default = "";
+   if (Message.length() < tag.length())
+      return Default;
+   std::transform(tag.begin(), tag.end(), tag.begin(), tolower_ascii);
+   auto valuestart = Message.cbegin();
+   // maybe the message starts directly with tag
+   if (Message[tag.length() - 2] == ':')
+   {
+      std::string lowstart = std::string("\n") + Message.substr(0, tag.length() - 1);
+      std::transform(lowstart.begin(), lowstart.end(), lowstart.begin(), tolower_ascii);
+      if (lowstart == tag)
+	 valuestart = std::next(valuestart, tag.length() - 1);
+   }
+   // the tag is somewhere in the message
+   if (valuestart == Message.cbegin())
+   {
+      auto const tagbegin = std::search(Message.cbegin(), Message.cend(), tag.cbegin(), tag.cend(),
+					[](char const a, char const b) { return tolower_ascii(a) == b; });
+      if (tagbegin == Message.cend())
+	 return Default;
+      valuestart = std::next(tagbegin, tag.length());
+   }
+   auto const is_whitespace = [](char const c) { return isspace_ascii(c) != 0 && c != '\n'; };
+   auto const is_newline = [](char const c) { return c == '\n'; };
+   std::string result;
+   valuestart = std::find_if_not(valuestart, Message.cend(), is_whitespace);
+   // is the first line of the value empty?
+   if (valuestart != Message.cend() && *valuestart == '\n')
+   {
+      valuestart = std::next(valuestart);
+      if (valuestart != Message.cend() && *valuestart == ' ')
+	 valuestart = std::next(valuestart);
+   }
+   // extract the value over multiple lines removing trailing whitespace
+   while (valuestart < Message.cend())
+   {
+      auto const linebreak = std::find_if(valuestart, Message.cend(), is_newline);
+      auto valueend = std::prev(linebreak);
+      // skip spaces at the end of the line
+      while (valueend > valuestart && is_whitespace(*valueend))
+	 valueend = std::prev(valueend);
+      // append found line to result
+      {
+	 std::string tmp(valuestart, std::next(valueend));
+	 if (tmp != ".")
+	 {
+	    if (result.empty())
+	       result.assign(std::move(tmp));
+	    else
+	       result.append(tmp);
+	 }
+      }
+      // see if the value is multiline
+      if (linebreak == Message.cend())
+	 break;
+      valuestart = std::next(linebreak);
+      if (valuestart == Message.cend() || *valuestart != ' ')
+	 break;
+      result.append("\n");
+      // skip the space leading a multiline (Keep all other whitespaces in the value)
+      valuestart = std::next(valuestart);
+   }
+   auto const valueend = result.find_last_not_of("\n");
+   if (valueend == std::string::npos)
+      result.clear();
+   else
+      result.erase(valueend + 1);
+   return result;
+}
+									/*}}}*/
+// StringToBool - Converts a string into a boolean			/*{{{*/
+// ---------------------------------------------------------------------
+/* This inspects the string to see if it is true or if it is false and
+   then returns the result. Several variants on true/false are checked. */
+int StringToBool(const string &Text,int Default)
+{
+   char *ParseEnd;
+   int Res = strtol(Text.c_str(),&ParseEnd,0);
+   // ensure that the entire string was converted by strtol to avoid
+   // failures on "apt-cache show -a 0ad" where the "0" is converted
+   const char *TextEnd = Text.c_str()+Text.size();
+   if (ParseEnd == TextEnd && Res >= 0 && Res <= 1)
+      return Res;
+   
+   // Check for positives
+   if (strcasecmp(Text.c_str(),"no") == 0 ||
+       strcasecmp(Text.c_str(),"false") == 0 ||
+       strcasecmp(Text.c_str(),"without") == 0 ||
+       strcasecmp(Text.c_str(),"off") == 0 ||
+       strcasecmp(Text.c_str(),"disable") == 0)
+      return 0;
+   
+   // Check for negatives
+   if (strcasecmp(Text.c_str(),"yes") == 0 ||
+       strcasecmp(Text.c_str(),"true") == 0 ||
+       strcasecmp(Text.c_str(),"with") == 0 ||
+       strcasecmp(Text.c_str(),"on") == 0 ||
+       strcasecmp(Text.c_str(),"enable") == 0)
+      return 1;
+   
+   return Default;
+}
+									/*}}}*/
+// TimeRFC1123 - Convert a time_t into RFC1123 format			/*{{{*/
+// ---------------------------------------------------------------------
+/* This converts a time_t into a string time representation that is
+   year 2000 compliant and timezone neutral */
+string TimeRFC1123(time_t Date, bool const NumericTimezone)
+{
+   struct tm Conv;
+   if (gmtime_r(&Date, &Conv) == NULL)
+      return "";
+
+   auto const posix = std::locale::classic();
+   std::ostringstream datestr;
+   datestr.imbue(posix);
+   APT::StringView const fmt("%a, %d %b %Y %H:%M:%S");
+   std::use_facet<std::time_put<char>>(posix).put(
+                    std::ostreambuf_iterator<char>(datestr),
+                    datestr, ' ', &Conv, fmt.data(), fmt.data() + fmt.size());
+   if (NumericTimezone)
+      datestr << " +0000";
+   else
+      datestr << " GMT";
+   return datestr.str();
+}
+									/*}}}*/
+// ReadMessages - Read messages from the FD				/*{{{*/
+// ---------------------------------------------------------------------
+/* This pulls full messages from the input FD into the message buffer. 
+   It assumes that messages will not pause during transit so no
+   fancy buffering is used.
+
+   In particular: this reads blocks from the input until it believes
+   that it's run out of input text.  Each block is terminated by a
+   double newline ('\n' followed by '\n').
+ */
+bool ReadMessages(int Fd, vector<string> &List)
+{
+   char Buffer[64000];
+   // Represents any left-over from the previous iteration of the
+   // parse loop.  (i.e., if a message is split across the end
+   // of the buffer, it goes here)
+   string PartialMessage;
+
+   do {
+      int const Res = read(Fd, Buffer, sizeof(Buffer));
+      if (Res < 0 && errno == EINTR)
+	 continue;
+
+      // process we read from has died
+      if (Res == 0)
+	 return false;
+
+      // No data
+#if EAGAIN != EWOULDBLOCK
+      if (Res < 0 && (errno == EAGAIN || errno == EWOULDBLOCK))
+#else
+      if (Res < 0 && errno == EAGAIN)
+#endif
+	 return true;
+      if (Res < 0)
+	 return false;
+
+      // extract the message(s) from the buffer
+      char const *Start = Buffer;
+      char const * const End = Buffer + Res;
+
+      char const * NL = (char const *) memchr(Start, '\n', End - Start);
+      if (NL == NULL)
+      {
+	 // end of buffer: store what we have so far and read new data in
+	 PartialMessage.append(Start, End - Start);
+	 Start = End;
+      }
+      else
+	 ++NL;
+
+      if (PartialMessage.empty() == false && Start < End)
+      {
+	 // if we start with a new line, see if the partial message we have ended with one
+	 // so that we properly detect records ending between two read() runs
+	 // cases are: \n|\n  ,  \r\n|\r\n  and  \r\n\r|\n
+	 // the case \r|\n\r\n is handled by the usual double-newline handling
+	 if ((NL - Start) == 1 || ((NL - Start) == 2 && *Start == '\r'))
+	 {
+	    if (APT::String::Endswith(PartialMessage, "\n") || APT::String::Endswith(PartialMessage, "\r\n\r"))
+	    {
+	       PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+	       List.push_back(PartialMessage);
+	       PartialMessage.clear();
+	       while (NL < End && (*NL == '\n' || *NL == '\r')) ++NL;
+	       Start = NL;
+	    }
+	 }
+      }
+
+      while (Start < End) {
+	 char const * NL2 = (char const *) memchr(NL, '\n', End - NL);
+	 if (NL2 == NULL)
+	 {
+	    // end of buffer: store what we have so far and read new data in
+	    PartialMessage.append(Start, End - Start);
+	    break;
+	 }
+	 ++NL2;
+
+	 // did we find a double newline?
+	 if ((NL2 - NL) == 1 || ((NL2 - NL) == 2 && *NL == '\r'))
+	 {
+	    PartialMessage.append(Start, NL2 - Start);
+	    PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+	    List.push_back(PartialMessage);
+	    PartialMessage.clear();
+	    while (NL2 < End && (*NL2 == '\n' || *NL2 == '\r')) ++NL2;
+	    Start = NL2;
+	 }
+	 NL = NL2;
+      }
+
+      // we have read at least one complete message and nothing left
+      if (PartialMessage.empty() == true)
+	 return true;
+
+      if (WaitFd(Fd) == false)
+	 return false;
+   } while (true);
+}
+									/*}}}*/
+// MonthConv - Converts a month string into a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This was lifted from the boa webserver which lifted it from 'wn-v1.07'
+   Made it a bit more robust with a few tolower_ascii though. */
+static int MonthConv(char const * const Month)
+{
+   switch (tolower_ascii(*Month)) 
+   {
+      case 'a':
+      return tolower_ascii(Month[1]) == 'p'?3:7;
+      case 'd':
+      return 11;
+      case 'f':
+      return 1;
+      case 'j':
+      if (tolower_ascii(Month[1]) == 'a')
+	 return 0;
+      return tolower_ascii(Month[2]) == 'n'?5:6;
+      case 'm':
+      return tolower_ascii(Month[2]) == 'r'?2:4;
+      case 'n':
+      return 10;
+      case 'o':
+      return 9;
+      case 's':
+      return 8;
+
+      // Pretend it is January..
+      default:
+      return 0;
+   }   
+}
+									/*}}}*/
+// timegm - Internal timegm if the gnu version is not available		/*{{{*/
+// ---------------------------------------------------------------------
+/* Converts struct tm to time_t, assuming the data in tm is UTC rather
+   than local timezone (mktime assumes the latter).
+
+   This function is a nonstandard GNU extension that is also present on
+   the BSDs and maybe other systems. For others we follow the advice of
+   the manpage of timegm and use his portable replacement. */
+#ifndef HAVE_TIMEGM
+static time_t timegm(struct tm *t)
+{
+   char *tz = getenv("TZ");
+   setenv("TZ", "", 1);
+   tzset();
+   time_t ret = mktime(t);
+   if (tz)
+      setenv("TZ", tz, 1);
+   else
+      unsetenv("TZ");
+   tzset();
+   return ret;
+}
+#endif
+									/*}}}*/
+// RFC1123StrToTime - Converts an HTTP1.1 full date strings into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* tries to parses a full date as specified in RFC7231 §7.1.1.1
+   with one exception: HTTP/1.1 valid dates need to have GMT as timezone.
+   As we encounter dates from UTC or with a numeric timezone in other places,
+   we allow them here to to be able to reuse the method. Either way, a date
+   must be in UTC or parsing will fail. Previous implementations of this
+   method used to ignore the timezone and assume always UTC. */
+bool RFC1123StrToTime(std::string const &str,time_t &time)
+{
+   unsigned short day = 0;
+   signed int year = 0; // yes, Y23K problem – we going to worry then…
+   std::string weekday, month, datespec, timespec, zone;
+   std::istringstream ss(str);
+   auto const &posix = std::locale::classic();
+   ss.imbue(posix);
+   ss >> weekday;
+   // we only superficially check weekday, mostly to avoid accepting localized
+   // weekdays here and take only its length to decide which datetime format we
+   // encounter here. The date isn't stored.
+   std::transform(weekday.begin(), weekday.end(), weekday.begin(), ::tolower);
+   std::array<char const * const, 7> c_weekdays = {{ "sun", "mon", "tue", "wed", "thu", "fri", "sat" }};
+   if (std::find(c_weekdays.begin(), c_weekdays.end(), weekday.substr(0,3)) == c_weekdays.end())
+      return false;
+
+   switch (weekday.length())
+   {
+   case 4:
+      // Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
+      if (weekday[3] != ',')
+	 return false;
+      ss >> day >> month >> year >> timespec >> zone;
+      break;
+   case 3:
+      // Sun Nov  6 08:49:37 1994 ; ANSI C's asctime() format
+      ss >> month >> day >> timespec >> year;
+      zone = "UTC";
+      break;
+   case 0:
+   case 1:
+   case 2:
+      return false;
+   default:
+      // Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
+      if (weekday[weekday.length() - 1] != ',')
+	 return false;
+      ss >> datespec >> timespec >> zone;
+      auto const expldate = VectorizeString(datespec, '-');
+      if (expldate.size() != 3)
+	 return false;
+      try {
+	 size_t pos;
+	 day = std::stoi(expldate[0], &pos);
+	 if (pos != expldate[0].length())
+	    return false;
+	 year = 1900 + std::stoi(expldate[2], &pos);
+	 if (pos != expldate[2].length())
+	    return false;
+	 strprintf(datespec, "%.4d-%.2d-%.2d", year, MonthConv(expldate[1].c_str()) + 1, day);
+      } catch (...) {
+         return false;
+      }
+      break;
+   }
+
+   if (ss.fail() || ss.bad() || !ss.eof())
+      return false;
+
+   if (zone != "GMT" && zone != "UTC" && zone != "Z") // RFC 822
+   {
+      // numeric timezones as a should of RFC 1123 and generally preferred
+      try {
+	 size_t pos;
+	 auto const z = std::stoi(zone, &pos);
+	 if (z != 0 || pos != zone.length())
+	    return false;
+      } catch (...) {
+	 return false;
+      }
+   }
+
+   if (datespec.empty())
+   {
+      if (month.empty())
+	 return false;
+      strprintf(datespec, "%.4d-%.2d-%.2d", year, MonthConv(month.c_str()) + 1, day);
+   }
+
+   std::string const datetime = datespec + ' ' + timespec;
+   struct tm Tm;
+   if (strptime(datetime.c_str(), "%Y-%m-%d %H:%M:%S", &Tm) == nullptr)
+      return false;
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
+// FTPMDTMStrToTime - Converts a ftp modification date into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FTPMDTMStrToTime(const char* const str,time_t &time)
+{
+   struct tm Tm;
+   // MDTM includes no whitespaces but recommend and ignored by strptime
+   if (strptime(str, "%Y %m %d %H %M %S", &Tm) == NULL)
+      return false;
+
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
+// StrToNum - Convert a fixed length string to a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the crazy fixed length string headers in
+   tar and ar files. */
+bool StrToNum(const char *Str,unsigned long &Res,unsigned Len,unsigned Base)
+{
+   unsigned long long BigRes;
+   if (not StrToNum(Str, BigRes, Len, Base))
+      return false;
+
+   if (std::numeric_limits<unsigned long>::max() < BigRes)
+      return false;
+
+   Res = BigRes;
+   return true;
+}
+									/*}}}*/
+// StrToNum - Convert a fixed length string to a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the crazy fixed length string headers in
+   tar and ar files. */
+bool StrToNum(const char *Str,unsigned long long &Res,unsigned Len,unsigned Base)
+{
+   char S[30];
+   if (Len >= sizeof(S))
+      return false;
+   memcpy(S,Str,Len);
+   S[Len] = 0;
+
+   // All spaces is a zero
+   Res = 0;
+   unsigned I;
+   for (I = 0; S[I] == ' '; ++I);
+   if (S[I] == 0)
+      return true;
+   if (S[I] == '-')
+      return false;
+
+   char *End;
+   errno = 0;
+   Res = strtoull(S,&End,Base);
+   return not (End == S || errno != 0);
+}
+									/*}}}*/
+
+// Base256ToNum - Convert a fixed length binary to a number             /*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the 256bit encoded fixed length fields in
+   tar files */
+bool Base256ToNum(const char *Str,unsigned long long &Res,unsigned int Len)
+{
+   if ((Str[0] & 0x80) == 0)
+      return false;
+   else
+   {
+      Res = Str[0] & 0x7F;
+      for(unsigned int i = 1; i < Len; ++i)
+         Res = (Res<<8) + Str[i];
+      return true;
+   }
+}
+									/*}}}*/
+// Base256ToNum - Convert a fixed length binary to a number             /*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the 256bit encoded fixed length fields in
+   tar files */
+bool Base256ToNum(const char *Str,unsigned long &Res,unsigned int Len)
+{
+   unsigned long long Num = 0;
+   bool rc;
+
+   rc = Base256ToNum(Str, Num, Len);
+   // rudimentary check for overflow (Res = ulong, Num = ulonglong)
+   Res = Num;
+   if (Res != Num)
+      return false;
+
+   return rc;
+}
+									/*}}}*/
+// HexDigit - Convert a hex character into an integer			/*{{{*/
+// ---------------------------------------------------------------------
+/* Helper for Hex2Num */
+static int HexDigit(int c)
+{   
+   if (c >= '0' && c <= '9')
+      return c - '0';
+   if (c >= 'a' && c <= 'f')
+      return c - 'a' + 10;
+   if (c >= 'A' && c <= 'F')
+      return c - 'A' + 10;
+   return -1;
+}
+									/*}}}*/
+// Hex2Num - Convert a long hex number into a buffer			/*{{{*/
+// ---------------------------------------------------------------------
+/* The length of the buffer must be exactly 1/2 the length of the string. */
+bool Hex2Num(const APT::StringView Str,unsigned char *Num,unsigned int Length)
+{
+   if (Str.length() != Length*2)
+      return false;
+   
+   // Convert each digit. We store it in the same order as the string
+   int J = 0;
+   for (auto I = Str.begin(); I != Str.end();J++, I += 2)
+   {
+      int first_half = HexDigit(I[0]);
+      int second_half;
+      if (first_half < 0)
+	 return false;
+      
+      second_half = HexDigit(I[1]);
+      if (second_half < 0)
+	 return false;
+      Num[J] = first_half << 4;
+      Num[J] += second_half;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// TokSplitString - Split a string up by a given token			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is intended to be a faster splitter, it does not use dynamic
+   memories. Input is changed to insert nulls at each token location. */
+bool TokSplitString(char Tok,char *Input,char **List,
+		    unsigned long ListMax)
+{
+   // Strip any leading spaces
+   char *Start = Input;
+   char *Stop = Start + strlen(Start);
+   for (; *Start != 0 && isspace(*Start) != 0; Start++);
+
+   unsigned long Count = 0;
+   char *Pos = Start;
+   while (Pos != Stop)
+   {
+      // Skip to the next Token
+      for (; Pos != Stop && *Pos != Tok; Pos++);
+      
+      // Back remove spaces
+      char *End = Pos;
+      for (; End > Start && (End[-1] == Tok || isspace(End[-1]) != 0); End--);
+      *End = 0;
+      
+      List[Count++] = Start;
+      if (Count >= ListMax)
+      {
+	 List[Count-1] = 0;
+	 return false;
+      }
+      
+      // Advance pos
+      for (; Pos != Stop && (*Pos == Tok || isspace(*Pos) != 0 || *Pos == 0); Pos++);
+      Start = Pos;
+   }
+   
+   List[Count] = 0;
+   return true;
+}
+									/*}}}*/
+// VectorizeString - Split a string up into a vector of strings		/*{{{*/
+// ---------------------------------------------------------------------
+/* This can be used to split a given string up into a vector, so the
+   propose is the same as in the method above and this one is a bit slower
+   also, but the advantage is that we have an iteratable vector */
+vector<string> VectorizeString(string const &haystack, char const &split)
+{
+   vector<string> exploded;
+   if (haystack.empty() == true)
+      return exploded;
+   string::const_iterator start = haystack.begin();
+   string::const_iterator end = start;
+   do {
+      for (; end != haystack.end() && *end != split; ++end);
+      exploded.push_back(string(start, end));
+      start = end + 1;
+   } while (end != haystack.end() && (++end) != haystack.end());
+   return exploded;
+}
+									/*}}}*/
+// StringSplit - split a string into a string vector by token		/*{{{*/
+// ---------------------------------------------------------------------
+/* See header for details.
+ */
+vector<string> StringSplit(std::string const &s, std::string const &sep,
+                           unsigned int maxsplit)
+{
+   vector<string> split;
+   size_t start, pos;
+
+   // no separator given, this is bogus
+   if(sep.size() == 0)
+      return split;
+
+   start = pos = 0;
+   while (pos != string::npos)
+   {
+      pos = s.find(sep, start);
+      split.push_back(s.substr(start, pos-start));
+      
+      // if maxsplit is reached, the remaining string is the last item
+      if(split.size() >= maxsplit)
+      {
+         split[split.size()-1] = s.substr(start);
+         break;
+      }
+      start = pos+sep.size();
+   }
+   return split;
+}
+									/*}}}*/
+// RegexChoice - Simple regex list/list matcher				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned long RegexChoice(RxChoiceList *Rxs,const char **ListBegin,
+		      const char **ListEnd)
+{
+   for (RxChoiceList *R = Rxs; R->Str != 0; R++)
+      R->Hit = false;
+
+   unsigned long Hits = 0;
+   for (; ListBegin < ListEnd; ++ListBegin)
+   {
+      // Check if the name is a regex
+      const char *I;
+      bool Regex = true;
+      for (I = *ListBegin; *I != 0; I++)
+	 if (*I == '.' || *I == '?' || *I == '*' || *I == '|')
+	    break;
+      if (*I == 0)
+	 Regex = false;
+	 
+      // Compile the regex pattern
+      regex_t Pattern;
+      if (Regex == true)
+	 if (regcomp(&Pattern,*ListBegin,REG_EXTENDED | REG_ICASE |
+		     REG_NOSUB) != 0)
+	    Regex = false;
+	 
+      // Search the list
+      bool Done = false;
+      for (RxChoiceList *R = Rxs; R->Str != 0; R++)
+      {
+	 if (R->Str[0] == 0)
+	    continue;
+	 
+	 if (strcasecmp(R->Str,*ListBegin) != 0)
+	 {
+	    if (Regex == false)
+	       continue;
+	    if (regexec(&Pattern,R->Str,0,0,0) != 0)
+	       continue;
+	 }
+	 Done = true;
+	 
+	 if (R->Hit == false)
+	    Hits++;
+	 
+	 R->Hit = true;
+      }
+      
+      if (Regex == true)
+	 regfree(&Pattern);
+      
+      if (Done == false)
+	 _error->Warning(_("Selection %s not found"),*ListBegin);
+   }
+   
+   return Hits;
+}
+									/*}}}*/
+// {str,io}printf - C format string outputter to C++ strings/iostreams	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to make the internationalization strings easier to translate
+   and to allow reordering of parameters */
+bool iovprintf(std::ostream &out, const char *format,
+		      va_list &args, ssize_t &size) {
+   auto S = std::unique_ptr<char,decltype(&free)>{static_cast<char*>(malloc(size)), &free};
+   ssize_t const n = vsnprintf(S.get(), size, format, args);
+   if (n > -1 && n < size) {
+      out << S.get();
+      return true;
+   } else {
+      if (n > -1)
+	 size = n + 1;
+      else
+	 size *= 2;
+   }
+   return false;
+}
+void ioprintf(ostream &out,const char *format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(out, format, args, size);
+      va_end(args);
+      if (ret == true)
+	 return;
+   }
+}
+void strprintf(string &out,const char *format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   std::ostringstream outstr;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(outstr, format, args, size);
+      va_end(args);
+      if (ret == true)
+	 break;
+   }
+   out = outstr.str();
+}
+									/*}}}*/
+// safe_snprintf - Safer snprintf					/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a snprintf that will never (ever) go past 'End' and returns a
+   pointer to the end of the new string. The returned string is always null
+   terminated unless Buffer == end. This is a better alterantive to using
+   consecutive snprintfs. */
+char *safe_snprintf(char *Buffer,char *End,const char *Format,...)
+{
+   va_list args;
+   int Did;
+
+   if (End <= Buffer)
+      return End;
+   va_start(args,Format);
+   Did = vsnprintf(Buffer,End - Buffer,Format,args);
+   va_end(args);
+
+   if (Did < 0 || Buffer + Did > End)
+      return End;
+   return Buffer + Did;
+}
+									/*}}}*/
+// StripEpoch - Remove the version "epoch" from a version string	/*{{{*/
+// ---------------------------------------------------------------------
+string StripEpoch(const string &VerStr)
+{
+   size_t i = VerStr.find(":");
+   if (i == string::npos)
+      return VerStr;
+   return VerStr.substr(i+1);
+}
+									/*}}}*/
+
+// tolower_ascii - tolower() function that ignores the locale		/*{{{*/
+// ---------------------------------------------------------------------
+/* This little function is the most called method we have and tries
+   therefore to do the absolute minimum - and is notable faster than
+   standard tolower/toupper and as a bonus avoids problems with different
+   locales - we only operate on ascii chars anyway. */
+#undef tolower_ascii
+int tolower_ascii(int const c) APT_PURE APT_COLD;
+int tolower_ascii(int const c)
+{
+   return tolower_ascii_inline(c);
+}
+									/*}}}*/
+
+// isspace_ascii - isspace() function that ignores the locale		/*{{{*/
+// ---------------------------------------------------------------------
+/* This little function is one of the most called methods we have and tries
+   therefore to do the absolute minimum - and is notable faster than
+   standard isspace() and as a bonus avoids problems with different
+   locales - we only operate on ascii chars anyway. */
+#undef isspace_ascii
+int isspace_ascii(int const c) APT_PURE APT_COLD;
+int isspace_ascii(int const c)
+{
+   return isspace_ascii_inline(c);
+}
+									/*}}}*/
+
+// CheckDomainList - See if Host is in a , separate list		/*{{{*/
+// ---------------------------------------------------------------------
+/* The domain list is a comma separate list of domains that are suffix
+   matched against the argument */
+bool CheckDomainList(const string &Host,const string &List)
+{
+   string::const_iterator Start = List.begin();
+   for (string::const_iterator Cur = List.begin(); Cur <= List.end(); ++Cur)
+   {
+      if (Cur < List.end() && *Cur != ',')
+	 continue;
+      
+      // Match the end of the string..
+      if ((Host.size() >= (unsigned)(Cur - Start)) &&
+	  Cur - Start != 0 &&
+	  stringcasecmp(Host.end() - (Cur - Start),Host.end(),Start,Cur) == 0)
+	 return true;
+      
+      Start = Cur + 1;
+   }
+   return false;
+}
+									/*}}}*/
+// strv_length - Return the length of a NULL-terminated string array	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+size_t strv_length(const char **str_array)
+{
+   size_t i;
+   for (i=0; str_array[i] != NULL; i++)
+      /* nothing */
+      ;
+   return i;
+}
+									/*}}}*/
+// DeEscapeString - unescape (\0XX and \xXX) from a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string DeEscapeString(const string &input)
+{
+   char tmp[3];
+   string::const_iterator it;
+   string output;
+   for (it = input.begin(); it != input.end(); ++it)
+   {
+      // just copy non-escape chars
+      if (*it != '\\')
+      {
+         output += *it;
+         continue;
+      }
+
+      // deal with double escape
+      if (*it == '\\' && 
+          (it + 1 < input.end()) &&  it[1] == '\\')
+      {
+         // copy
+         output += *it;
+         // advance iterator one step further
+         ++it;
+         continue;
+      }
+        
+      // ensure we have a char to read
+      if (it + 1 == input.end())
+         continue;
+
+      // read it
+      ++it;
+      switch (*it)
+      {
+         case '0':
+            if (it + 2 < input.end()) {
+               tmp[0] = it[1];
+               tmp[1] = it[2];
+               tmp[2] = 0;
+               output += (char)strtol(tmp, 0, 8);
+               it += 2;
+            } else {
+	       // FIXME: raise exception here?
+	    }
+            break;
+         case 'x':
+            if (it + 2 < input.end()) {
+               tmp[0] = it[1];
+               tmp[1] = it[2];
+               tmp[2] = 0;
+               output += (char)strtol(tmp, 0, 16);
+               it += 2;
+            } else {
+	       // FIXME: raise exception here?
+	    }
+            break;
+         default:
+            // FIXME: raise exception here?
+            break;
+      }
+   }
+   return output;
+}
+									/*}}}*/
+// URI::CopyFrom - Copy from an object					/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses the URI into all of its components */
+void URI::CopyFrom(const string &U)
+{
+   string::const_iterator I = U.begin();
+
+   // Locate the first colon, this separates the scheme
+   for (; I < U.end() && *I != ':' ; ++I);
+   string::const_iterator FirstColon = I;
+
+   /* Determine if this is a host type URI with a leading double //
+      and then search for the first single / */
+   string::const_iterator SingleSlash = I;
+   if (I + 3 < U.end() && I[1] == '/' && I[2] == '/')
+      SingleSlash += 3;
+   
+   /* Find the / indicating the end of the hostname, ignoring /'s in the
+      square brackets */
+   bool InBracket = false;
+   for (; SingleSlash < U.end() && (*SingleSlash != '/' || InBracket == true); ++SingleSlash)
+   {
+      if (*SingleSlash == '[')
+	 InBracket = true;
+      if (InBracket == true && *SingleSlash == ']')
+	 InBracket = false;
+   }
+   
+   if (SingleSlash > U.end())
+      SingleSlash = U.end();
+
+   // We can now write the access and path specifiers
+   Access.assign(U.begin(),FirstColon);
+   if (SingleSlash != U.end())
+      Path.assign(SingleSlash,U.end());
+   if (Path.empty() == true)
+      Path = "/";
+
+   // Now we attempt to locate a user:pass@host fragment
+   if (FirstColon + 2 <= U.end() && FirstColon[1] == '/' && FirstColon[2] == '/')
+      FirstColon += 3;
+   else
+      FirstColon += 1;
+   if (FirstColon >= U.end())
+      return;
+   
+   if (FirstColon > SingleSlash)
+      FirstColon = SingleSlash;
+   
+   // Find the colon...
+   I = FirstColon + 1;
+   if (I > SingleSlash)
+      I = SingleSlash;
+
+   // Search for the @ separating user:pass from host
+   auto const RevAt = std::find(
+	 std::string::const_reverse_iterator(SingleSlash),
+	 std::string::const_reverse_iterator(I), '@');
+   string::const_iterator const At = RevAt.base() == I ? SingleSlash : std::prev(RevAt.base());
+   // and then look for the colon between user and pass
+   string::const_iterator const SecondColon = std::find(I, At, ':');
+
+   // Now write the host and user/pass
+   if (At == SingleSlash)
+   {
+      if (FirstColon < SingleSlash)
+	 Host.assign(FirstColon,SingleSlash);
+   }
+   else
+   {
+      Host.assign(At+1,SingleSlash);
+      // username and password must be encoded (RFC 3986)
+      User.assign(DeQuoteString(FirstColon,SecondColon));
+      if (SecondColon < At)
+	 Password.assign(DeQuoteString(SecondColon+1,At));
+   }   
+   
+   // Now we parse the RFC 2732 [] hostnames.
+   unsigned long PortEnd = 0;
+   InBracket = false;
+   for (unsigned I = 0; I != Host.length();)
+   {
+      if (Host[I] == '[')
+      {
+	 InBracket = true;
+	 Host.erase(I,1);
+	 continue;
+      }
+      
+      if (InBracket == true && Host[I] == ']')
+      {
+	 InBracket = false;
+	 Host.erase(I,1);
+	 PortEnd = I;
+	 continue;
+      }
+      I++;
+   }
+   
+   // Tsk, weird.
+   if (InBracket == true)
+   {
+      Host.clear();
+      return;
+   }
+   
+   // Now we parse off a port number from the hostname
+   Port = 0;
+   string::size_type Pos = Host.rfind(':');
+   if (Pos == string::npos || Pos < PortEnd)
+      return;
+   
+   Port = atoi(string(Host,Pos+1).c_str());
+   Host.assign(Host,0,Pos);
+}
+									/*}}}*/
+// URI::operator string - Convert the URI to a string			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+URI::operator string()
+{
+   std::stringstream Res;
+
+   if (Access.empty() == false)
+      Res << Access << ':';
+
+   if (Host.empty() == false)
+   {
+      if (Access.empty() == false)
+	 Res << "//";
+
+      if (User.empty() == false)
+      {
+	 // FIXME: Technically userinfo is permitted even less
+	 // characters than these, but this is not conveniently
+	 // expressed with a denylist.
+	 Res << QuoteString(User, ":/?#[]@");
+	 if (Password.empty() == false)
+	    Res << ":" << QuoteString(Password, ":/?#[]@");
+	 Res << "@";
+      }
+
+      // Add RFC 2732 escaping characters
+      if (Access.empty() == false && Host.find_first_of("/:") != string::npos)
+	 Res << '[' << Host << ']';
+      else
+	 Res << Host;
+
+      if (Port != 0)
+	 Res << ':' << std::to_string(Port);
+   }
+
+   if (Path.empty() == false)
+   {
+      if (Path[0] != '/')
+	 Res << "/" << Path;
+      else
+	 Res << Path;
+   }
+
+   return Res.str();
+}
+									/*}}}*/
+// URI::SiteOnly - Return the schema and site for the URI		/*{{{*/
+string URI::SiteOnly(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   U.Path.clear();
+   return U;
+}
+									/*}}}*/
+// URI::ArchiveOnly - Return the schema, site and cleaned path for the URI /*{{{*/
+string URI::ArchiveOnly(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   if (U.Path.empty() == false && U.Path[U.Path.length() - 1] == '/')
+      U.Path.erase(U.Path.length() - 1);
+   return U;
+}
+									/*}}}*/
+// URI::NoUserPassword - Return the schema, site and path for the URI	/*{{{*/
+string URI::NoUserPassword(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   return U;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/strutl.h b/apt-pkg/contrib/strutl.h
new file mode 100644
index 0000000..1fdc8dc
--- /dev/null
+++ b/apt-pkg/contrib/strutl.h
@@ -0,0 +1,252 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   String Util - These are some useful string functions
+   
+   _strstrip is a function to remove whitespace from the front and end
+   of a string.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@gpu.srv.ualberta.ca>   
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef STRUTL_H
+#define STRUTL_H
+
+#include <cstring>
+#include <iostream>
+#include <limits>
+#include <string>
+#include <vector>
+#include <apt-pkg/string_view.h>
+#include <stddef.h>
+#include <time.h>
+
+#include "macros.h"
+
+
+namespace APT {
+   namespace String {
+      APT_PUBLIC std::string Strip(const std::string &s);
+      APT_PUBLIC bool Endswith(const std::string &s, const std::string &ending);
+      APT_PUBLIC bool Startswith(const std::string &s, const std::string &starting);
+      APT_PUBLIC std::string Join(std::vector<std::string> list, const std::string &sep);
+      // Returns string display length honoring multi-byte characters
+      APT_PUBLIC size_t DisplayLength(StringView str);
+   }
+}
+
+
+APT_PUBLIC bool UTF8ToCodeset(const char *codeset, const std::string &orig, std::string *dest);
+APT_PUBLIC char *_strstrip(char *String);
+APT_PUBLIC char *_strrstrip(char *String); // right strip only
+APT_DEPRECATED_MSG("Use SubstVar to avoid memory headaches") APT_PUBLIC char *_strtabexpand(char *String,size_t Len);
+APT_PUBLIC bool ParseQuoteWord(const char *&String,std::string &Res);
+APT_PUBLIC bool ParseCWord(const char *&String,std::string &Res);
+APT_PUBLIC std::string QuoteString(const std::string &Str,const char *Bad);
+APT_PUBLIC std::string DeQuoteString(const std::string &Str);
+APT_PUBLIC std::string DeQuoteString(std::string::const_iterator const &begin, std::string::const_iterator const &end);
+
+// unescape (\0XX and \xXX) from a string
+APT_PUBLIC std::string DeEscapeString(const std::string &input);
+
+APT_PUBLIC std::string SizeToStr(double Bytes);
+APT_PUBLIC std::string TimeToStr(unsigned long Sec);
+APT_PUBLIC std::string Base64Encode(const std::string &Str);
+APT_PUBLIC std::string OutputInDepth(const unsigned long Depth, const char* Separator="  ");
+APT_PUBLIC std::string URItoFileName(const std::string &URI);
+/** returns a datetime string as needed by HTTP/1.1 and Debian files.
+ *
+ * Note: The date will always be represented in a UTC timezone
+ *
+ * @param Date to be represented as a string
+ * @param NumericTimezone is preferred in general, but HTTP/1.1 requires the use
+ *    of GMT as timezone instead. \b true means that the timezone should be denoted
+ *    as "+0000" while \b false uses "GMT".
+ */
+APT_PUBLIC std::string TimeRFC1123(time_t Date, bool const NumericTimezone);
+/** parses time as needed by HTTP/1.1 and Debian files.
+ *
+ * HTTP/1.1 prefers dates in RFC1123 format (but the other two obsolete date formats
+ * are supported to) and e.g. Release files use the same format in Date & Valid-Until
+ * fields.
+ *
+ * Note: datetime strings need to be in UTC timezones (GMT, UTC, Z, +/-0000) to be
+ * parsed. Other timezones will be rejected as invalid. Previous implementations
+ * accepted other timezones, but treated them as UTC.
+ *
+ * @param str is the datetime string to parse
+ * @param[out] time will be the seconds since epoch of the given datetime if
+ *    parsing is successful, undefined otherwise.
+ * @return \b true if parsing was successful, otherwise \b false.
+ */
+APT_PUBLIC bool RFC1123StrToTime(const std::string &str,time_t &time) APT_MUSTCHECK;
+APT_PUBLIC bool FTPMDTMStrToTime(const char* const str,time_t &time) APT_MUSTCHECK;
+APT_PUBLIC std::string LookupTag(const std::string &Message,const char *Tag,const char *Default = 0);
+APT_PUBLIC int StringToBool(const std::string &Text,int Default = -1);
+APT_PUBLIC bool ReadMessages(int Fd, std::vector<std::string> &List);
+APT_PUBLIC bool StrToNum(const char *Str,unsigned long &Res,unsigned Len,unsigned Base = 0);
+APT_PUBLIC bool StrToNum(const char *Str,unsigned long long &Res,unsigned Len,unsigned Base = 0);
+APT_PUBLIC bool Base256ToNum(const char *Str,unsigned long &Res,unsigned int Len);
+APT_PUBLIC bool Base256ToNum(const char *Str,unsigned long long &Res,unsigned int Len);
+APT_PUBLIC bool Hex2Num(const APT::StringView Str,unsigned char *Num,unsigned int Length);
+// input changing string split
+APT_PUBLIC bool TokSplitString(char Tok,char *Input,char **List,
+		    unsigned long ListMax);
+
+// split a given string by a char
+APT_PUBLIC std::vector<std::string> VectorizeString(std::string const &haystack, char const &split) APT_PURE;
+
+/* \brief Return a vector of strings from string "input" where "sep"
+ * is used as the delimiter string.
+ *
+ * \param input The input string.
+ *
+ * \param sep The separator to use.
+ *
+ * \param maxsplit (optional) The maximum amount of splitting that
+ * should be done .
+ * 
+ * The optional "maxsplit" argument can be used to limit the splitting,
+ * if used the string is only split on maxsplit places and the last
+ * item in the vector contains the remainder string.
+ */
+APT_PUBLIC std::vector<std::string> StringSplit(std::string const &input,
+                                     std::string const &sep, 
+                                     unsigned int maxsplit=std::numeric_limits<unsigned int>::max()) APT_PURE;
+
+
+APT_HIDDEN bool iovprintf(std::ostream &out, const char *format, va_list &args, ssize_t &size);
+APT_PUBLIC void ioprintf(std::ostream &out,const char *format,...) APT_PRINTF(2);
+APT_PUBLIC void strprintf(std::string &out,const char *format,...) APT_PRINTF(2);
+APT_PUBLIC char *safe_snprintf(char *Buffer,char *End,const char *Format,...) APT_PRINTF(3);
+APT_PUBLIC bool CheckDomainList(const std::string &Host, const std::string &List);
+
+/* Do some compat mumbo jumbo */
+#define tolower_ascii  tolower_ascii_inline
+#define isspace_ascii  isspace_ascii_inline
+
+APT_PURE APT_HOT
+static inline int tolower_ascii_unsafe(int const c)
+{
+   return c | 0x20;
+}
+APT_PURE APT_HOT
+static inline int tolower_ascii_inline(int const c)
+{
+   return (c >= 'A' && c <= 'Z') ? c + 32 : c;
+}
+APT_PURE APT_HOT
+static inline int isspace_ascii_inline(int const c)
+{
+   // 9='\t',10='\n',11='\v',12='\f',13='\r',32=' '
+   return (c >= 9 && c <= 13) || c == ' ';
+}
+APT_PURE APT_HOT
+static inline int islower_ascii(int const c)
+{
+   return c >= 'a' && c <= 'z';
+}
+APT_PURE APT_HOT
+static inline int isupper_ascii(int const c)
+{
+   return c >= 'A' && c <= 'Z';
+}
+APT_PURE APT_HOT
+static inline int isalpha_ascii(int const c)
+{
+   return isupper_ascii(c) || islower_ascii(c);
+}
+
+APT_PUBLIC std::string StripEpoch(const std::string &VerStr);
+
+#define APT_MKSTRCMP(name,func) \
+inline APT_PURE int name(const char *A,const char *B) {return func(A,A+strlen(A),B,B+strlen(B));} \
+inline APT_PURE int name(const char *A,const char *AEnd,const char *B) {return func(A,AEnd,B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const char *B) {return func(A.c_str(),A.c_str()+A.length(),B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const std::string& B) {return func(A.c_str(),A.c_str()+A.length(),B.c_str(),B.c_str()+B.length());} \
+inline APT_PURE int name(const std::string& A,const char *B,const char *BEnd) {return func(A.c_str(),A.c_str()+A.length(),B,BEnd);}
+
+#define APT_MKSTRCMP2(name,func) \
+inline APT_PURE int name(const char *A,const char *AEnd,const char *B) {return func(A,AEnd,B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const char *B) {return func(A.begin(),A.end(),B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const std::string& B) {return func(A.begin(),A.end(),B.begin(),B.end());} \
+inline APT_PURE int name(const std::string& A,const char *B,const char *BEnd) {return func(A.begin(),A.end(),B,BEnd);}
+
+APT_PUBLIC int APT_PURE stringcmp(const char *A,const char *AEnd,const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(const char *A,const char *AEnd,const char *B,const char *BEnd);
+
+/* We assume that GCC 3 indicates that libstdc++3 is in use too. In that
+   case the definition of string::const_iterator is not the same as
+   const char * and we need these extra functions */
+#if __GNUC__ >= 3
+APT_PUBLIC int APT_PURE stringcmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+	      const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+	      std::string::const_iterator B,std::string::const_iterator BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+		  const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+                  std::string::const_iterator B,std::string::const_iterator BEnd);
+
+inline APT_PURE int stringcmp(std::string::const_iterator A,std::string::const_iterator Aend,const char *B) {return stringcmp(A,Aend,B,B+strlen(B));}
+inline APT_PURE int stringcasecmp(std::string::const_iterator A,std::string::const_iterator Aend,const char *B) {return stringcasecmp(A,Aend,B,B+strlen(B));}
+#endif
+
+APT_MKSTRCMP2(stringcmp,stringcmp)
+APT_MKSTRCMP2(stringcasecmp,stringcasecmp)
+
+// Return the length of a NULL-terminated string array
+APT_PUBLIC size_t APT_PURE strv_length(const char **str_array);
+
+
+inline const char *DeNull(const char *s) {return (s == 0?"(null)":s);}
+
+class APT_PUBLIC URI
+{
+   void CopyFrom(const std::string &From);
+
+   public:
+
+   std::string Access;
+   std::string User;
+   std::string Password;
+   std::string Host;
+   std::string Path;
+   unsigned int Port;
+   
+   operator std::string();
+   inline void operator =(const std::string &From) {CopyFrom(From);}
+   inline bool empty() {return Access.empty();};
+   static std::string SiteOnly(const std::string &URI);
+   static std::string ArchiveOnly(const std::string &URI);
+   static std::string NoUserPassword(const std::string &URI);
+
+   explicit URI(std::string Path) { CopyFrom(Path); }
+   URI() : Port(0) {}
+};
+
+struct SubstVar
+{
+   const char *Subst;
+   const std::string *Contents;
+};
+APT_PUBLIC std::string SubstVar(std::string Str,const struct SubstVar *Vars);
+APT_PUBLIC std::string SubstVar(const std::string &Str,const std::string &Subst,const std::string &Contents);
+
+struct RxChoiceList
+{
+   void *UserData;
+   const char *Str;
+   bool Hit;
+};
+APT_PUBLIC unsigned long RegexChoice(RxChoiceList *Rxs,const char **ListBegin,
+		      const char **ListEnd);
+
+#endif
diff --git a/apt-pkg/contrib/weakptr.h b/apt-pkg/contrib/weakptr.h
new file mode 100644
index 0000000..8de727d
--- /dev/null
+++ b/apt-pkg/contrib/weakptr.h
@@ -0,0 +1,64 @@
+/* weakptr.h - An object which supports weak pointers.
+ *
+ * Copyright (C) 2010 Julian Andres Klode <jak@debian.org>
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#ifndef WEAK_POINTER_H
+#define WEAK_POINTER_H
+
+#include <set>
+#include <stddef.h>
+
+/**
+ * Class for objects providing support for weak pointers.
+ *
+ * This class allows for the registration of certain pointers as weak,
+ * which will cause them to be set to NULL when the destructor of the
+ * object is called.
+ */
+class WeakPointable {
+private:
+    std::set<WeakPointable**> pointers;
+
+public:
+
+    /**
+     * Add a new weak pointer.
+     */
+    inline void AddWeakPointer(WeakPointable** weakptr) {
+       pointers.insert(weakptr);
+    }
+
+    /**
+     * Remove the weak pointer from the list of weak pointers.
+     */
+    inline void RemoveWeakPointer(WeakPointable **weakptr) {
+       pointers.erase(weakptr);
+    }
+
+    /**
+     * Deconstruct the object, set all weak pointers to NULL.
+     */
+    ~WeakPointable() {
+        std::set<WeakPointable**>::iterator iter = pointers.begin();
+        while (iter != pointers.end())
+            **(iter++) = NULL;
+    }
+};
+
+#endif // WEAK_POINTER_H
diff --git a/apt-pkg/deb/debfile.cc b/apt-pkg/deb/debfile.cc
new file mode 100644
index 0000000..645a579
--- /dev/null
+++ b/apt-pkg/deb/debfile.cc
@@ -0,0 +1,274 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Archive File (.deb)
+   
+   .DEB archives are AR files containing two tars and an empty marker
+   member called 'debian-binary'. The two tars contain the meta data and
+   the actual archive contents. Thus this class is a very simple wrapper
+   around ar/tar to simply extract the right tar files.
+   
+   It also uses the deb package list parser to parse the control file 
+   into the cache.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/arfile.h>
+#include <apt-pkg/debfile.h>
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/extracttar.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <string>
+#include <sstream>
+#include <vector>
+#include <string.h>
+#include <sys/stat.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// DebFile::debDebFile - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* Open the AR file and check for consistency */
+debDebFile::debDebFile(FileFd &File) : File(File), AR(File)
+{
+   if (_error->PendingError() == true)
+      return;
+
+   if (!CheckMember("debian-binary")) {
+      _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "debian-binary");
+      return;
+   }
+
+   if (!CheckMember("control.tar") &&
+       !CheckMember("control.tar.gz") &&
+       !CheckMember("control.tar.xz") &&
+       !CheckMember("control.tar.zst"))
+   {
+      _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "control.tar");
+      return;
+   }
+
+   if (!CheckMember("data.tar") &&
+       !CheckMember("data.tar.gz") &&
+       !CheckMember("data.tar.bz2") &&
+       !CheckMember("data.tar.lzma") &&
+       !CheckMember("data.tar.xz") &&
+       !CheckMember("data.tar.zst"))
+   {
+      _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "data.tar");
+      return;
+   }
+}
+									/*}}}*/
+// DebFile::CheckMember - Check if a named member is in the archive	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to check for a correct deb and to give nicer error messages
+   for people playing around. */
+bool debDebFile::CheckMember(const char *Name)
+{
+   if (AR.FindMember(Name) == 0)
+      return false;
+   return true;
+}
+									/*}}}*/
+// DebFile::GotoMember - Jump to a Member				/*{{{*/
+// ---------------------------------------------------------------------
+/* Jump in the file to the start of a named member and return the information
+   about that member. The caller can then read from the file up to the 
+   returned size. Note, since this relies on the file position this is
+   a destructive operation, it also changes the last returned Member
+   structure - so don't nest them! */
+const ARArchive::Member *debDebFile::GotoMember(const char *Name)
+{
+   // Get the archive member and positition the file
+   const ARArchive::Member *Member = AR.FindMember(Name);
+   if (Member == 0)
+   {
+      return 0;
+   }
+   if (File.Seek(Member->Start) == false)
+      return 0;
+      
+   return Member;
+}
+									/*}}}*/
+// DebFile::ExtractTarMember - Extract the contents of a tar member	/*{{{*/
+// ---------------------------------------------------------------------
+/* Simple wrapper around tar.. */
+bool debDebFile::ExtractTarMember(pkgDirStream &Stream,const char *Name)
+{
+   std::string Compressor;
+   auto const Compressors = APT::Configuration::getCompressors();
+
+   ARArchive::Member const *Member = AR.FindMember(Name);
+   if (Member != nullptr)
+   {
+      auto const found = std::find_if(Compressors.cbegin(), Compressors.cend(), [&](auto const &c) {
+	 return not c.Extension.empty() && APT::String::Endswith(Name, c.Extension);
+      });
+      if (found != Compressors.cend())
+	 Compressor = found->Name;
+   }
+   else
+   {
+      for (auto const &c : Compressors)
+      {
+	 if (c.Extension.empty())
+	    continue;
+	 Member = AR.FindMember(std::string(Name).append(c.Extension).c_str());
+	 if (Member == nullptr)
+	    continue;
+	 Compressor = c.Name;
+	 break;
+      }
+   }
+
+   if (Member == nullptr)
+   {
+      std::ostringstream ext;
+      ext << Name << '{';
+      for (auto const &c : Compressors)
+	 if (not c.Extension.empty())
+	    ext << c.Extension << ',';
+      ext << '}';
+      return _error->Error(_("Internal error, could not locate member %s"), ext.str().c_str());
+   }
+
+   if (not File.Seek(Member->Start))
+      return false;
+
+   ExtractTar Tar(File,Member->Size,Compressor);
+   if (_error->PendingError())
+      return false;
+   return Tar.Go(Stream);
+}
+									/*}}}*/
+// DebFile::ExtractArchive - Extract the archive data itself		/*{{{*/
+// ---------------------------------------------------------------------
+/* Simple wrapper around DebFile::ExtractTarMember. */
+bool debDebFile::ExtractArchive(pkgDirStream &Stream)
+{
+   return ExtractTarMember(Stream, "data.tar");
+}
+									/*}}}*/
+
+// DebFile::ControlExtract::DoItem - Control Tar Extraction		/*{{{*/
+// ---------------------------------------------------------------------
+/* This directory stream handler for the control tar handles extracting
+   it into the temporary meta directory. It only extracts files, it does
+   not create directories, links or anything else. */
+bool debDebFile::ControlExtract::DoItem(Item &Itm,int &Fd)
+{
+   if (Itm.Type != Item::File)
+      return true;
+   
+   /* Cleanse the file name, prevent people from trying to unpack into
+      absolute paths, .., etc */
+   for (char *I = Itm.Name; *I != 0; I++)
+      if (*I == '/')
+	 *I = '_';
+
+   /* Force the ownership to be root and ensure correct permissions, 
+      go-w, the rest are left untouched */
+   Itm.UID = 0;
+   Itm.GID = 0;
+   Itm.Mode &= ~(S_IWGRP | S_IWOTH);
+   
+   return pkgDirStream::DoItem(Itm,Fd);
+}
+									/*}}}*/
+
+// MemControlExtract::DoItem - Check if it is the control file		/*{{{*/
+// ---------------------------------------------------------------------
+/* This sets up to extract the control block member file into a memory 
+   block of just the right size. All other files go into the bit bucket. */
+
+// Upper size limit for control files. Two reasons for having a limit here:
+//
+// 1. We read those files into memory and want to avoid being killed by OOM
+//
+// 2. We allocate (Itm.Size+2)-large arrays, so this can overflow if Itm.Size
+// becomes 2**64-2 or larger. This is obviously
+//
+// 64 MiB seems like a terribly large size that everyone should be happy with.
+static const unsigned long long DEB_CONTROL_SIZE_LIMIT = 64 * 1024 * 1024;
+bool debDebFile::MemControlExtract::DoItem(Item &Itm,int &Fd)
+{
+   // At the control file, allocate buffer memory.
+   if (Member == Itm.Name)
+   {
+      if (Itm.Size > DEB_CONTROL_SIZE_LIMIT)
+	 return _error->Error("Control file too large: %llu > %llu bytes", Itm.Size, DEB_CONTROL_SIZE_LIMIT);
+      delete [] Control;
+      Control = new char[Itm.Size+2];
+      IsControl = true;
+      Fd = -2; // Signal to pass to Process
+      Length = Itm.Size;
+   }   
+   else
+      IsControl = false;
+   
+   return true;
+}
+									/*}}}*/
+// MemControlExtract::Process - Process extracting the control file	/*{{{*/
+// ---------------------------------------------------------------------
+/* Just memcopy the block from the tar extractor and put it in the right
+   place in the pre-allocated memory block. */
+bool debDebFile::MemControlExtract::Process(Item &/*Itm*/,const unsigned char *Data,
+			     unsigned long long Size,unsigned long long Pos)
+{
+   memcpy(Control + Pos, Data,Size);
+   return true;
+}
+									/*}}}*/
+// MemControlExtract::Read - Read the control information from the deb	/*{{{*/
+// ---------------------------------------------------------------------
+/* This uses the internal tar extractor to fetch the control file, and then
+   it parses it into a tag section parser. */
+bool debDebFile::MemControlExtract::Read(debDebFile &Deb)
+{
+   if (Deb.ExtractTarMember(*this, "control.tar") == false)
+      return false;
+
+   if (Control == 0)
+      return true;
+   
+   Control[Length] = '\n';
+   Control[Length+1] = '\n';
+   if (Section.Scan(Control,Length+2) == false)
+      return _error->Error(_("Unparsable control file"));
+   return true;
+}
+									/*}}}*/
+// MemControlExtract::TakeControl - Parse a memory block		/*{{{*/
+// ---------------------------------------------------------------------
+/* The given memory block is loaded into the parser and parsed as a control
+   record. */
+bool debDebFile::MemControlExtract::TakeControl(const void *Data,unsigned long long Size)
+{
+   if (Size > DEB_CONTROL_SIZE_LIMIT)
+      return _error->Error("Control file too large: %llu > %llu bytes", Size, DEB_CONTROL_SIZE_LIMIT);
+
+   delete [] Control;
+   Control = new char[Size+2];
+   Length = Size;
+   memcpy(Control,Data,Size);
+   
+   Control[Length] = '\n';
+   Control[Length+1] = '\n';
+   return Section.Scan(Control,Length+2);
+}
+									/*}}}*/
+
diff --git a/apt-pkg/deb/debfile.h b/apt-pkg/deb/debfile.h
new file mode 100644
index 0000000..48a75ae
--- /dev/null
+++ b/apt-pkg/deb/debfile.h
@@ -0,0 +1,89 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Archive File (.deb)
+
+   This Class handles all the operations performed directly on .deb 
+   files. It makes use of the AR and TAR classes to give the necessary
+   external interface.
+   
+   There are only two things that can be done with a raw package, 
+   extract it's control information and extract the contents itself. 
+
+   This should probably subclass an as-yet unwritten super class to
+   produce a generic archive mechanism.
+  
+   The memory control file extractor is useful to extract a single file
+   into memory from the control.tar.gz
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBFILE_H
+#define PKGLIB_DEBFILE_H
+
+#include <apt-pkg/arfile.h>
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/tagfile.h>
+
+#include <string>
+
+
+class FileFd;
+
+class APT_PUBLIC debDebFile
+{
+   protected:
+   
+   FileFd &File;
+   ARArchive AR;
+   
+   bool CheckMember(const char *Name);
+   
+   public:
+   class ControlExtract;
+   class MemControlExtract;
+
+   bool ExtractTarMember(pkgDirStream &Stream, const char *Name);
+   bool ExtractArchive(pkgDirStream &Stream);
+   const ARArchive::Member *GotoMember(const char *Name);
+   inline FileFd &GetFile() {return File;};
+   
+   explicit debDebFile(FileFd &File);
+};
+
+class APT_PUBLIC debDebFile::ControlExtract : public pkgDirStream
+{
+   public:
+   
+   virtual bool DoItem(Item &Itm,int &Fd) APT_OVERRIDE;
+};
+
+class APT_PUBLIC debDebFile::MemControlExtract : public pkgDirStream
+{
+   bool IsControl;
+   
+   public:
+   
+   char *Control;
+   pkgTagSection Section;
+   unsigned long Length;
+   std::string Member;
+   
+   // Members from DirStream
+   virtual bool DoItem(Item &Itm,int &Fd) APT_OVERRIDE;
+   virtual bool Process(Item &Itm,const unsigned char *Data,
+			unsigned long long Size,unsigned long long Pos) APT_OVERRIDE;
+
+   // Helpers
+   bool Read(debDebFile &Deb);
+   bool TakeControl(const void *Data,unsigned long long Size);
+
+   MemControlExtract() : IsControl(false), Control(0), Length(0), Member("control") {};
+   explicit MemControlExtract(std::string Member) : IsControl(false), Control(0), Length(0), Member(Member) {};
+   ~MemControlExtract() {delete [] Control;};   
+};
+									/*}}}*/
+
+#endif
diff --git a/apt-pkg/deb/debindexfile.cc b/apt-pkg/deb/debindexfile.cc
new file mode 100644
index 0000000..e1698e1
--- /dev/null
+++ b/apt-pkg/deb/debindexfile.cc
@@ -0,0 +1,421 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Specific sources.list types and the three sorts of Debian
+   index files.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apti18n.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debfile.h>
+#include <apt-pkg/debindexfile.h>
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/debrecords.h>
+#include <apt-pkg/debsrcrecords.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+#include <apt-pkg/srcrecords.h>
+#include <apt-pkg/strutl.h>
+
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <stdio.h>
+
+#include <sys/stat.h>
+#include <unistd.h>
+									/*}}}*/
+
+// Sources Index							/*{{{*/
+debSourcesIndex::debSourcesIndex(IndexTarget const &Target,bool const Trusted) :
+     pkgDebianIndexTargetFile(Target, Trusted), d(NULL)
+{
+}
+std::string debSourcesIndex::SourceInfo(pkgSrcRecords::Parser const &Record,
+				   pkgSrcRecords::File const &File) const
+{
+   // The result looks like: http://foo/debian/ stable/main src 1.1.1 (dsc)
+   std::string Res = Target.Description;
+   Res.erase(Target.Description.rfind(' '));
+
+   Res += " ";
+   Res += Record.Package();
+   Res += " ";
+   Res += Record.Version();
+   if (File.Type.empty() == false)
+      Res += " (" + File.Type + ")";
+   return Res;
+}
+pkgSrcRecords::Parser *debSourcesIndex::CreateSrcParser() const
+{
+   std::string const SourcesURI = IndexFileName();
+   if (FileExists(SourcesURI))
+      return new debSrcRecordParser(SourcesURI, this);
+   return NULL;
+}
+bool debSourcesIndex::OpenListFile(FileFd &, std::string const &)
+{
+   return true;
+}
+pkgCacheListParser * debSourcesIndex::CreateListParser(FileFd &)
+{
+   return nullptr;
+}
+uint8_t debSourcesIndex::GetIndexFlags() const
+{
+   return 0;
+}
+									/*}}}*/
+// Packages Index							/*{{{*/
+debPackagesIndex::debPackagesIndex(IndexTarget const &Target, bool const Trusted) :
+                  pkgDebianIndexTargetFile(Target, Trusted), d(NULL)
+{
+}
+std::string debPackagesIndex::ArchiveInfo(pkgCache::VerIterator const &Ver) const
+{
+   std::string Res = Target.Description;
+   {
+      auto const space = Target.Description.rfind(' ');
+      if (space != std::string::npos)
+	 Res.erase(space);
+   }
+
+   Res += " ";
+   Res += Ver.ParentPkg().Name();
+   Res += " ";
+   std::string const Dist = Target.Option(IndexTarget::RELEASE);
+   if (Dist.empty() == false && Dist[Dist.size() - 1] != '/')
+      Res.append(Ver.Arch()).append(" ");
+   Res += Ver.VerStr();
+   return Res;
+}
+uint8_t debPackagesIndex::GetIndexFlags() const
+{
+   return 0;
+}
+									/*}}}*/
+// Translation-* Index							/*{{{*/
+debTranslationsIndex::debTranslationsIndex(IndexTarget const &Target) :
+			pkgDebianIndexTargetFile(Target, true), d(NULL)
+{}
+bool debTranslationsIndex::HasPackages() const
+{
+   return Exists();
+}
+bool debTranslationsIndex::OpenListFile(FileFd &Pkg, std::string const &FileName)
+{
+   if (FileExists(FileName))
+      return pkgDebianIndexTargetFile::OpenListFile(Pkg, FileName);
+   return true;
+}
+uint8_t debTranslationsIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::NotSource | pkgCache::Flag::NoPackages;
+}
+std::string debTranslationsIndex::GetArchitecture() const
+{
+   return std::string();
+}
+pkgCacheListParser * debTranslationsIndex::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new debTranslationsParser(&Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+									/*}}}*/
+// dpkg/status Index							/*{{{*/
+debStatusIndex::debStatusIndex(std::string const &File) : pkgDebianIndexRealFile(File, true), d(NULL)
+{
+}
+std::string debStatusIndex::GetArchitecture() const
+{
+   return std::string();
+}
+std::string debStatusIndex::GetComponent() const
+{
+   return "now";
+}
+uint8_t debStatusIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::NotSource;
+}
+
+pkgCacheListParser * debStatusIndex::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new debStatusListParser(&Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+									/*}}}*/
+// DebPkgFile Index - a single .deb file as an index			/*{{{*/
+debDebPkgFileIndex::debDebPkgFileIndex(std::string const &DebFile)
+   : pkgDebianIndexRealFile(DebFile, true), d(NULL), DebFile(DebFile)
+{
+}
+bool debDebPkgFileIndex::GetContent(std::ostream &content, std::string const &debfile)
+{
+   struct stat Buf;
+   if (stat(debfile.c_str(), &Buf) != 0)
+      return false;
+
+   FileFd debFd(debfile, FileFd::ReadOnly);
+   debDebFile deb(debFd);
+   debDebFile::MemControlExtract extractor("control");
+
+   if (not extractor.Read(deb))
+      return _error->Error(_("Could not read meta data from %s"), debfile.c_str());
+
+   // trim off newlines
+   while (extractor.Control[extractor.Length] == '\n')
+      extractor.Control[extractor.Length--] = '\0';
+   const char *Control = extractor.Control;
+   while (isspace_ascii(Control[0]))
+      Control++;
+
+   content << Control << '\n';
+   content << "Filename: " << debfile << "\n";
+   content << "Size: " << std::to_string(Buf.st_size) << "\n";
+
+   return true;
+}
+bool debDebPkgFileIndex::OpenListFile(FileFd &Pkg, std::string const &FileName)
+{
+   // write the control data to a tempfile
+   if (GetTempFile("deb-file-" + flNotDir(FileName), true, &Pkg) == NULL)
+      return false;
+   std::ostringstream content;
+   if (GetContent(content, FileName) == false)
+      return false;
+   std::string const contentstr = content.str();
+   if (contentstr.empty())
+      return true;
+   if (Pkg.Write(contentstr.c_str(), contentstr.length()) == false || Pkg.Seek(0) == false)
+      return false;
+   return true;
+}
+pkgCacheListParser * debDebPkgFileIndex::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new debDebFileParser(&Pkg, DebFile));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+uint8_t debDebPkgFileIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::LocalSource;
+}
+std::string debDebPkgFileIndex::GetArchitecture() const
+{
+   return std::string();
+}
+std::string debDebPkgFileIndex::GetComponent() const
+{
+   return "local-deb";
+}
+pkgCache::PkgFileIterator debDebPkgFileIndex::FindInCache(pkgCache &Cache) const
+{
+   std::string const FileName = IndexFileName();
+   pkgCache::PkgFileIterator File = Cache.FileBegin();
+   for (; File.end() == false; ++File)
+   {
+       if (File.FileName() == NULL || FileName != File.FileName())
+	 continue;
+      // we can't do size checks here as file size != content size
+      return File;
+   }
+
+   return File;
+}
+std::string debDebPkgFileIndex::ArchiveInfo(pkgCache::VerIterator const &Ver) const
+{
+   std::string Res = IndexFileName() + " ";
+   Res.append(Ver.ParentPkg().Name()).append(" ");
+   Res.append(Ver.Arch()).append(" ");
+   Res.append(Ver.VerStr());
+   return Res;
+}
+									/*}}}*/
+// DscFile Index - a single .dsc file as an index			/*{{{*/
+debDscFileIndex::debDscFileIndex(std::string const &DscFile)
+   : pkgDebianIndexRealFile(DscFile, true), d(NULL)
+{
+}
+pkgSrcRecords::Parser *debDscFileIndex::CreateSrcParser() const
+{
+   if (Exists() == false)
+      return NULL;
+   return new debDscRecordParser(File, this);
+}
+std::string debDscFileIndex::GetComponent() const
+{
+   return "local-dsc";
+}
+std::string debDscFileIndex::GetArchitecture() const
+{
+   return "source";
+}
+uint8_t debDscFileIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::LocalSource;
+}
+									/*}}}*/
+// ControlFile Index - a directory with a debian/control file		/*{{{*/
+std::string debDebianSourceDirIndex::GetComponent() const
+{
+   return "local-control";
+}
+									/*}}}*/
+// String Package Index - a string of Packages file content		/*{{{*/
+std::string debStringPackageIndex::GetArchitecture() const
+{
+   return std::string();
+}
+std::string debStringPackageIndex::GetComponent() const
+{
+   return "apt-tmp-index";
+}
+uint8_t debStringPackageIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::NotSource;
+}
+const pkgIndexFile::Type *debStringPackageIndex::GetType() const
+{
+   return pkgIndexFile::Type::GetType("Debian Package Index");
+}
+debStringPackageIndex::debStringPackageIndex(std::string const &content) :
+   pkgDebianIndexRealFile("", false), d(NULL)
+{
+   FileFd fd;
+   GetTempFile("apt-tmp-index", false, &fd);
+   fd.Write(content.data(), content.length());
+   File = fd.Name();
+}
+debStringPackageIndex::~debStringPackageIndex()
+{
+   RemoveFile("~debStringPackageIndex", File);
+}
+									/*}}}*/
+
+// Index File types for Debian						/*{{{*/
+class APT_HIDDEN debIFTypeSrc : public pkgIndexFile::Type
+{
+   public:
+   debIFTypeSrc() {Label = "Debian Source Index";};
+};
+class APT_HIDDEN debIFTypePkg : public pkgIndexFile::Type
+{
+   public:
+   virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &File) const APT_OVERRIDE
+   {
+      return new debRecordParser(File.FileName(),*File.Cache());
+   };
+   debIFTypePkg() {Label = "Debian Package Index";};
+};
+class APT_HIDDEN debIFTypeTrans : public debIFTypePkg
+{
+   public:
+   debIFTypeTrans() {Label = "Debian Translation Index";};
+};
+class APT_HIDDEN debIFTypeStatus : public pkgIndexFile::Type
+{
+   public:
+   virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &File) const APT_OVERRIDE
+   {
+      return new debRecordParser(File.FileName(),*File.Cache());
+   };
+   debIFTypeStatus() {Label = "Debian dpkg status file";};
+};
+class APT_HIDDEN debIFTypeDebPkgFile : public pkgIndexFile::Type
+{
+   public:
+   virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &File) const APT_OVERRIDE
+   {
+      return new debDebFileRecordParser(File.FileName());
+   };
+   debIFTypeDebPkgFile() {Label = "Debian deb file";};
+};
+class APT_HIDDEN debIFTypeDscFile : public pkgIndexFile::Type
+{
+   public:
+   virtual pkgSrcRecords::Parser *CreateSrcPkgParser(std::string const &DscFile) const APT_OVERRIDE
+   {
+      return new debDscRecordParser(DscFile, NULL);
+   };
+   debIFTypeDscFile() {Label = "Debian dsc file";};
+};
+class APT_HIDDEN debIFTypeDebianSourceDir : public pkgIndexFile::Type
+{
+   public:
+   virtual pkgSrcRecords::Parser *CreateSrcPkgParser(std::string const &SourceDir) const APT_OVERRIDE
+   {
+      return new debDscRecordParser(SourceDir + std::string("/debian/control"), NULL);
+   };
+   debIFTypeDebianSourceDir() {Label = "Debian control file";};
+};
+
+APT_HIDDEN debIFTypeSrc _apt_Src;
+APT_HIDDEN debIFTypePkg _apt_Pkg;
+APT_HIDDEN debIFTypeTrans _apt_Trans;
+APT_HIDDEN debIFTypeStatus _apt_Status;
+APT_HIDDEN debIFTypeDebPkgFile _apt_DebPkgFile;
+// file based pseudo indexes
+APT_HIDDEN debIFTypeDscFile _apt_DscFile;
+APT_HIDDEN debIFTypeDebianSourceDir _apt_DebianSourceDir;
+
+const pkgIndexFile::Type *debSourcesIndex::GetType() const
+{
+   return &_apt_Src;
+}
+const pkgIndexFile::Type *debPackagesIndex::GetType() const
+{
+   return &_apt_Pkg;
+}
+const pkgIndexFile::Type *debTranslationsIndex::GetType() const
+{
+   return &_apt_Trans;
+}
+const pkgIndexFile::Type *debStatusIndex::GetType() const
+{
+   return &_apt_Status;
+}
+const pkgIndexFile::Type *debDebPkgFileIndex::GetType() const
+{
+   return &_apt_DebPkgFile;
+}
+const pkgIndexFile::Type *debDscFileIndex::GetType() const
+{
+   return &_apt_DscFile;
+}
+const pkgIndexFile::Type *debDebianSourceDirIndex::GetType() const
+{
+   return &_apt_DebianSourceDir;
+}
+									/*}}}*/
+
+debStatusIndex::~debStatusIndex() {}
+debPackagesIndex::~debPackagesIndex() {}
+debTranslationsIndex::~debTranslationsIndex() {}
+debSourcesIndex::~debSourcesIndex() {}
+
+debDebPkgFileIndex::~debDebPkgFileIndex() {}
+debDscFileIndex::~debDscFileIndex() {}
diff --git a/apt-pkg/deb/debindexfile.h b/apt-pkg/deb/debindexfile.h
new file mode 100644
index 0000000..57b3738
--- /dev/null
+++ b/apt-pkg/deb/debindexfile.h
@@ -0,0 +1,196 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Index Files
+   
+   There are three sorts currently
+   
+   Package files that have File: tags
+   Package files that don't (/var/lib/dpkg/status)
+   Source files
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBINDEXFILE_H
+#define PKGLIB_DEBINDEXFILE_H
+
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/srcrecords.h>
+
+#include <string>
+
+class OpProgress;
+class pkgAcquire;
+class pkgCacheGenerator;
+
+class debStatusIndex : public pkgDebianIndexRealFile
+{
+   void * const d;
+protected:
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual std::string GetComponent() const APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+
+public:
+
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE {return true;};
+   // Abort if the file does not exist.
+   virtual bool Exists() const APT_OVERRIDE {return true;};
+
+   virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+
+   explicit debStatusIndex(std::string const &File);
+   virtual ~debStatusIndex();
+};
+
+class debPackagesIndex : public pkgDebianIndexTargetFile
+{
+   void * const d;
+protected:
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   // Stuff for accessing files on remote items
+   virtual std::string ArchiveInfo(pkgCache::VerIterator const &Ver) const APT_OVERRIDE;
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE {return true;};
+
+   debPackagesIndex(IndexTarget const &Target, bool const Trusted);
+   virtual ~debPackagesIndex();
+};
+
+class debTranslationsIndex : public pkgDebianIndexTargetFile
+{
+   void * const d;
+protected:
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) APT_OVERRIDE;
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+
+public:
+
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE;
+
+   explicit debTranslationsIndex(IndexTarget const &Target);
+   virtual ~debTranslationsIndex();
+};
+
+class debSourcesIndex : public pkgDebianIndexTargetFile
+{
+   void * const d;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) APT_OVERRIDE;
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+
+   public:
+
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   // Stuff for accessing files on remote items
+   virtual std::string SourceInfo(pkgSrcRecords::Parser const &Record,
+			     pkgSrcRecords::File const &File) const APT_OVERRIDE;
+
+   // Interface for the record parsers
+   virtual pkgSrcRecords::Parser *CreateSrcParser() const APT_OVERRIDE;
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE {return false;};
+
+   debSourcesIndex(IndexTarget const &Target, bool const Trusted);
+   virtual ~debSourcesIndex();
+};
+
+class debDebPkgFileIndex : public pkgDebianIndexRealFile
+{
+   void * const d;
+   std::string DebFile;
+
+protected:
+   virtual std::string GetComponent() const APT_OVERRIDE;
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) APT_OVERRIDE;
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   /** get the control (file) content of the deb file
+    *
+    * @param[out] content of the control file
+    * @param debfile is the filename of the .deb-file
+    * @return \b true if successful, otherwise \b false.
+    */
+   static bool GetContent(std::ostream &content, std::string const &debfile);
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE {return true;}
+   virtual pkgCache::PkgFileIterator FindInCache(pkgCache &Cache) const APT_OVERRIDE;
+
+   // Interface for acquire
+
+   explicit debDebPkgFileIndex(std::string const &DebFile);
+   virtual ~debDebPkgFileIndex();
+
+   std::string ArchiveInfo(pkgCache::VerIterator const &Ver) const override;
+};
+
+class APT_PUBLIC debDscFileIndex : public pkgDebianIndexRealFile
+{
+   void * const d;
+
+protected:
+   virtual std::string GetComponent() const APT_OVERRIDE;
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+   virtual pkgSrcRecords::Parser *CreateSrcParser() const APT_OVERRIDE;
+   virtual bool HasPackages() const APT_OVERRIDE {return false;};
+
+   explicit debDscFileIndex(std::string const &DscFile);
+   virtual ~debDscFileIndex();
+};
+
+class debDebianSourceDirIndex : public debDscFileIndex
+{
+protected:
+   virtual std::string GetComponent() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+};
+
+class APT_PUBLIC debStringPackageIndex : public pkgDebianIndexRealFile
+{
+   void * const d;
+protected:
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual std::string GetComponent() const APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   // Interface for the Cache Generator
+   virtual bool HasPackages() const APT_OVERRIDE {return true;};
+   // Abort if the file does not exist.
+   virtual bool Exists() const APT_OVERRIDE {return true;};
+
+   explicit debStringPackageIndex(std::string const &content);
+   virtual ~debStringPackageIndex();
+};
+#endif
diff --git a/apt-pkg/deb/deblistparser.cc b/apt-pkg/deb/deblistparser.cc
new file mode 100644
index 0000000..6f47053
--- /dev/null
+++ b/apt-pkg/deb/deblistparser.cc
@@ -0,0 +1,1053 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Cache Generator - Generator for the cache structure.
+   
+   This builds the cache structure from the abstract package list parser. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <stddef.h>
+#include <string.h>
+									/*}}}*/
+
+using std::string;
+using APT::StringView;
+
+static const debListParser::WordList PrioList[] = {
+   {"required",pkgCache::State::Required},
+   {"important",pkgCache::State::Important},
+   {"standard",pkgCache::State::Standard},
+   {"optional",pkgCache::State::Optional},
+   {"extra",pkgCache::State::Extra},
+   {"", 0}};
+
+// ListParser::debListParser - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* Provide an architecture and only this one and "all" will be accepted
+   in Step(), if no Architecture is given we will accept every arch
+   we would accept in general with checkArchitecture() */
+debListParser::debListParser(FileFd *File) :
+   pkgCacheListParser(), Tags(File)
+{
+   // this dance allows an empty value to override the default
+   if (_config->Exists("pkgCacheGen::ForceEssential"))
+   {
+      forceEssential = _config->FindVector("pkgCacheGen::ForceEssential");
+      if (forceEssential.empty() == false && _config->Find("pkgCacheGen::ForceEssential").empty())
+	 forceEssential.emplace_back("apt");
+   }
+   else
+      forceEssential.emplace_back("apt");
+   forceImportant = _config->FindVector("pkgCacheGen::ForceImportant");
+   myArch = _config->Find("APT::Architecture");
+}
+									/*}}}*/
+// ListParser::Package - Return the package name			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is to return the name of the package this section describes */
+string debListParser::Package() {
+   string Result = Section.Find(pkgTagSection::Key::Package).to_string();
+
+   // Normalize mixed case package names to lower case, like dpkg does
+   // See Bug#807012 for details.
+   // Only do this when the package name does not contain a / - as that
+   // indicates that the package name was derived from a filename given
+   // to install or build-dep or similar (Bug#854794)
+   if (likely(Result.find('/') == string::npos))
+   {
+      for (char &c: Result)
+      {
+	 char l = tolower_ascii_inline(c);
+	 if (unlikely(l != c))
+	    c = l;
+      }
+   }
+
+   if(unlikely(Result.empty() == true))
+      _error->Error("Encountered a section with no Package: header");
+   return Result;
+}
+									/*}}}*/
+// ListParser::Architecture - Return the package arch			/*{{{*/
+// ---------------------------------------------------------------------
+/* This will return the Architecture of the package this section describes */
+APT::StringView debListParser::Architecture() {
+   auto const Arch = Section.Find(pkgTagSection::Key::Architecture);
+   return Arch.empty() ? "none" : Arch;
+}
+									/*}}}*/
+// ListParser::ArchitectureAll						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debListParser::ArchitectureAll() {
+   return Section.Find(pkgTagSection::Key::Architecture) == "all";
+}
+									/*}}}*/
+// ListParser::Version - Return the version string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is to return the string describing the version in debian form,
+   epoch:upstream-release. If this returns the blank string then the 
+   entry is assumed to only describe package properties */
+APT::StringView debListParser::Version()
+{
+   return Section.Find(pkgTagSection::Key::Version);
+}
+									/*}}}*/
+unsigned char debListParser::ParseMultiArch(bool const showErrors)	/*{{{*/
+{
+   unsigned char MA;
+   auto const MultiArch = Section.Find(pkgTagSection::Key::Multi_Arch);
+   if (MultiArch.empty() == true || MultiArch == "no")
+      MA = pkgCache::Version::No;
+   else if (MultiArch == "same") {
+      if (ArchitectureAll() == true)
+      {
+	 if (showErrors == true)
+	    _error->Warning("Architecture: all package '%s' can't be Multi-Arch: same",
+		  Package().c_str());
+	 MA = pkgCache::Version::No;
+      }
+      else
+	 MA = pkgCache::Version::Same;
+   }
+   else if (MultiArch == "foreign")
+      MA = pkgCache::Version::Foreign;
+   else if (MultiArch == "allowed")
+      MA = pkgCache::Version::Allowed;
+   else
+   {
+      if (showErrors == true)
+	 _error->Warning("Unknown Multi-Arch type '%s' for package '%s'",
+	       MultiArch.to_string().c_str(), Package().c_str());
+      MA = pkgCache::Version::No;
+   }
+
+   if (ArchitectureAll() == true)
+      MA |= pkgCache::Version::All;
+
+   return MA;
+}
+									/*}}}*/
+// ListParser::NewVersion - Fill in the version structure		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debListParser::NewVersion(pkgCache::VerIterator &Ver)
+{
+   const char *Start;
+   const char *Stop;
+
+   // Parse the section
+   if (Section.Find(pkgTagSection::Key::Section,Start,Stop) == true)
+   {
+      map_stringitem_t const idx = StoreString(pkgCacheGenerator::SECTION, Start, Stop - Start);
+      Ver->Section = idx;
+   }
+   // Parse the source package name
+   pkgCache::GrpIterator G = Ver.ParentPkg().Group();
+
+   // Setup the defaults
+   Ver->SourcePkgName = G->Name;
+   Ver->SourceVerStr = Ver->VerStr;
+
+   // Parse the name and version str
+   if (Section.Find(pkgTagSection::Key::Source,Start,Stop) == true)
+   {
+      const char * const Space = static_cast<const char *>(memchr(Start, ' ', Stop - Start));
+      pkgCache::VerIterator V;
+
+      if (Space != NULL)
+      {
+	 const char * const Open = static_cast<const char *>(memchr(Space, '(', Stop - Space));
+	 if (likely(Open != NULL))
+	 {
+	    const char * const Close = static_cast<const char *>(memchr(Open, ')', Stop - Open));
+	    if (likely(Close != NULL))
+	    {
+	       APT::StringView const version(Open + 1, (Close - Open) - 1);
+	       if (version != Ver.VerStr())
+	       {
+		  map_stringitem_t const idx = StoreString(pkgCacheGenerator::VERSIONNUMBER, version);
+		  G = Ver.ParentPkg().Group();
+		  Ver->SourceVerStr = idx;
+	       }
+	    }
+	 }
+	 Stop = Space;
+      }
+
+      APT::StringView const pkgname(Start, Stop - Start);
+      // Oh, our group is the wrong one for the source package. Make a new one.
+      if (pkgname != G.Name())
+      {
+	 if (not NewGroup(G, pkgname))
+	    return false;
+      }
+   }
+
+   // Link into by source package group.
+   Ver->SourcePkgName = G->Name;
+   Ver->NextInSource = G->VersionsInSource;
+   G->VersionsInSource = Ver.MapPointer();
+
+   Ver->MultiArch = ParseMultiArch(true);
+   // Archive Size
+   Ver->Size = Section.FindULL(pkgTagSection::Key::Size);
+   // Unpacked Size (in K)
+   Ver->InstalledSize = Section.FindULL(pkgTagSection::Key::Installed_Size);
+   Ver->InstalledSize *= 1024;
+
+   // Priority
+   if (Section.Find(pkgTagSection::Key::Priority,Start,Stop) == true)
+   {
+      if (GrabWord(StringView(Start,Stop-Start),PrioList,Ver->Priority) == false)
+	 Ver->Priority = pkgCache::State::Extra;
+   }
+
+   if (ParseDepends(Ver,pkgTagSection::Key::Pre_Depends,pkgCache::Dep::PreDepends) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Depends,pkgCache::Dep::Depends) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Conflicts,pkgCache::Dep::Conflicts) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Breaks,pkgCache::Dep::DpkgBreaks) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Recommends,pkgCache::Dep::Recommends) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Suggests,pkgCache::Dep::Suggests) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Replaces,pkgCache::Dep::Replaces) == false)
+      return false;
+   if (ParseDepends(Ver,pkgTagSection::Key::Enhances,pkgCache::Dep::Enhances) == false)
+      return false;
+
+   if (ParseProvides(Ver) == false)
+      return false;
+   if (not APT::KernelAutoRemoveHelper::getUname(Ver.ParentPkg().Name()).empty())
+   {
+      if (not NewProvides(Ver, "$kernel", "any", Ver.VerStr(), pkgCache::Flag::MultiArchImplicit))
+	 return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// ListParser::AvailableDescriptionLanguages				/*{{{*/
+std::vector<std::string> debListParser::AvailableDescriptionLanguages()
+{
+   std::vector<std::string> avail;
+   static constexpr int prefixLen = 12;
+   char buf[32] = "Description-";
+   if (Section.Exists(pkgTagSection::Key::Description))
+      avail.emplace_back();
+   for (auto const &lang : APT::Configuration::getLanguages(true))
+   {
+      if (unlikely(lang.size() > sizeof(buf) - prefixLen)) {
+	 _error->Warning("Ignoring translated description %s", lang.c_str());
+	 continue;
+      }
+      memcpy(buf + prefixLen, lang.c_str(), lang.size());
+      if (Section.Exists(StringView(buf, prefixLen + lang.size())) == true)
+	 avail.push_back(lang);
+   }
+   return avail;
+}
+									/*}}}*/
+// ListParser::Description_md5 - Return the description_md5 MD5SumValue	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is to return the md5 string to allow the check if it is the right
+   description. If no Description-md5 is found in the section it will be
+   calculated.
+ */
+APT::StringView debListParser::Description_md5()
+{
+   StringView const value = Section.Find(pkgTagSection::Key::Description_md5);
+   if (unlikely(value.empty() == true))
+   {
+      StringView const desc = Section.Find(pkgTagSection::Key::Description);
+      if (desc == "\n")
+	 return StringView();
+
+      Hashes md5(Hashes::MD5SUM);
+      md5.Add(desc.data(), desc.size());
+      md5.Add("\n");
+      MD5Buffer = md5.GetHashString(Hashes::MD5SUM).HashValue();
+      return StringView(MD5Buffer);
+   }
+   else if (likely(value.size() == 32))
+   {
+      return value;
+   }
+   _error->Error("Malformed Description-md5 line; doesn't have the required length (32 != %d) '%.*s'", (int)value.size(), (int)value.length(), value.data());
+   return StringView();
+}
+                                                                        /*}}}*/
+// ListParser::UsePackage - Update a package structure			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called to update the package with any new information 
+   that might be found in the section */
+bool debListParser::UsePackage(pkgCache::PkgIterator &Pkg,
+			       pkgCache::VerIterator &Ver)
+{
+   string const static myArch = _config->Find("APT::Architecture");
+   // Possible values are: "all", "native", "installed" and "none"
+   // The "installed" mode is handled by ParseStatus(), See #544481 and friends.
+   string const static essential = _config->Find("pkgCacheGen::Essential", "all");
+   if (essential == "all" ||
+       (essential == "native" && Pkg->Arch != 0 && myArch == Pkg.Arch()))
+      if (Section.FindFlag(pkgTagSection::Key::Essential,Pkg->Flags,pkgCache::Flag::Essential) == false)
+	 return false;
+   if (Section.FindFlag(pkgTagSection::Key::Important,Pkg->Flags,pkgCache::Flag::Important) == false)
+      return false;
+   if (Section.FindFlag(pkgTagSection::Key::Protected, Pkg->Flags, pkgCache::Flag::Important) == false)
+      return false;
+
+   if (std::find(forceEssential.begin(), forceEssential.end(), Pkg.Name()) != forceEssential.end())
+   {
+      if ((essential == "native" && Pkg->Arch != 0 && myArch == Pkg.Arch()) ||
+	  essential == "all")
+	 Pkg->Flags |= pkgCache::Flag::Essential | pkgCache::Flag::Important;
+      else
+	 Pkg->Flags |= pkgCache::Flag::Important;
+   }
+   else if (std::find(forceImportant.begin(), forceImportant.end(), Pkg.Name()) != forceImportant.end())
+      Pkg->Flags |= pkgCache::Flag::Important;
+
+   auto phased = Section.FindULL(pkgTagSection::Key::Phased_Update_Percentage, 100);
+   if (phased != 100)
+   {
+      if (not Ver.PhasedUpdatePercentage(phased))
+	 _error->Warning("Ignoring invalid Phased-Update-Percentage value");
+   }
+
+   if (ParseStatus(Pkg,Ver) == false)
+      return false;
+   return true;
+}
+									/*}}}*/
+// ListParser::VersionHash - Compute a unique hash for this version	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+uint32_t debListParser::VersionHash()
+{
+   static constexpr pkgTagSection::Key Sections[] ={
+      pkgTagSection::Key::Installed_Size,
+      pkgTagSection::Key::Depends,
+      pkgTagSection::Key::Pre_Depends,
+//    pkgTagSection::Key::Suggests,
+//    pkgTagSection::Key::Recommends",
+      pkgTagSection::Key::Conflicts,
+      pkgTagSection::Key::Breaks,
+      pkgTagSection::Key::Replaces};
+   unsigned long Result = 5381;
+   for (auto I : Sections)
+   {
+      const char *Start;
+      const char *End;
+      if (Section.Find(I,Start,End) == false)
+	 continue;
+      
+      /* Strip out any spaces from the text, this undoes dpkgs reformatting
+         of certain fields. dpkg also has the rather interesting notion of
+         reformatting depends operators < -> <=, so we drop all = from the
+	 string to make that not matter. */
+      for (; Start != End; ++Start)
+      {
+	 // Strip away 0: epochs from input
+	 if (*Start == '0' && Start[1] == ':') {
+	    Start++;	// Skip the :
+	    continue;	// Skip the 0
+	 }
+	 if (isspace_ascii(*Start) != 0 || *Start == '=')
+	    continue;
+	 Result = 33 * Result + tolower_ascii_unsafe(*Start);
+      }
+
+
+   }
+   
+   return Result;
+}
+									/*}}}*/
+// StatusListParser::ParseStatus - Parse the status field		/*{{{*/
+// ---------------------------------------------------------------------
+/* Status lines are of the form,
+     Status: want flag status
+   want = unknown, install, hold, deinstall, purge
+   flag = ok, reinstreq
+   status = not-installed, config-files, half-installed, unpacked,
+            half-configured, triggers-awaited, triggers-pending, installed
+ */
+bool debListParser::ParseStatus(pkgCache::PkgIterator &,
+				pkgCache::VerIterator &Ver)
+{
+   // the status file has no info about the download size and
+   // usually this is fine as we will have picked that info up already –
+   // except if we have volatile sources which are parsed after the status file.
+   if (Ver->Size == 0)
+      Ver->Size = Section.FindULL(pkgTagSection::Key::Size);
+   return true;
+}
+bool debStatusListParser::ParseStatus(pkgCache::PkgIterator &Pkg,
+				pkgCache::VerIterator &Ver)
+{
+   const char *Start;
+   const char *Stop;
+   if (Section.Find(pkgTagSection::Key::Status,Start,Stop) == false)
+      return true;
+
+   // UsePackage() is responsible for setting the flag in the default case
+   bool const static essential = _config->Find("pkgCacheGen::Essential", "") == "installed";
+   if (essential == true &&
+       Section.FindFlag(pkgTagSection::Key::Essential,Pkg->Flags,pkgCache::Flag::Essential) == false)
+      return false;
+
+   // Isolate the first word
+   const char *I = Start;
+   for(; I < Stop && *I != ' '; I++);
+   if (I >= Stop || *I != ' ')
+      return _error->Error("Malformed Status line");
+
+   // Process the want field
+   WordList WantList[] = {{"unknown",pkgCache::State::Unknown},
+                          {"install",pkgCache::State::Install},
+                          {"hold",pkgCache::State::Hold},
+                          {"deinstall",pkgCache::State::DeInstall},
+                          {"purge",pkgCache::State::Purge},
+                          {"", 0}};
+   if (GrabWord(StringView(Start,I-Start),WantList,Pkg->SelectedState) == false)
+      return _error->Error("Malformed 1st word in the Status line");
+
+   // Isloate the next word
+   I++;
+   Start = I;
+   for(; I < Stop && *I != ' '; I++);
+   if (I >= Stop || *I != ' ')
+      return _error->Error("Malformed status line, no 2nd word");
+
+   // Process the flag field
+   WordList FlagList[] = {{"ok",pkgCache::State::Ok},
+                          {"reinstreq",pkgCache::State::ReInstReq},
+                          {"hold",pkgCache::State::HoldInst},
+                          {"hold-reinstreq",pkgCache::State::HoldReInstReq},
+                          {"", 0}};
+   if (GrabWord(StringView(Start,I-Start),FlagList,Pkg->InstState) == false)
+      return _error->Error("Malformed 2nd word in the Status line");
+
+   // Isloate the last word
+   I++;
+   Start = I;
+   for(; I < Stop && *I != ' '; I++);
+   if (I != Stop)
+      return _error->Error("Malformed Status line, no 3rd word");
+
+   // Process the flag field
+   WordList StatusList[] = {{"not-installed",pkgCache::State::NotInstalled},
+                            {"config-files",pkgCache::State::ConfigFiles},
+                            {"half-installed",pkgCache::State::HalfInstalled},
+                            {"unpacked",pkgCache::State::UnPacked},
+                            {"half-configured",pkgCache::State::HalfConfigured},
+                            {"triggers-awaited",pkgCache::State::TriggersAwaited},
+                            {"triggers-pending",pkgCache::State::TriggersPending},
+                            {"installed",pkgCache::State::Installed},
+                            {"", 0}};
+   if (GrabWord(StringView(Start,I-Start),StatusList,Pkg->CurrentState) == false)
+      return _error->Error("Malformed 3rd word in the Status line");
+
+   /* A Status line marks the package as indicating the current
+      version as well. Only if it is actually installed.. Otherwise
+      the interesting dpkg handling of the status file creates bogus 
+      entries. */
+   if (!(Pkg->CurrentState == pkgCache::State::NotInstalled ||
+	 Pkg->CurrentState == pkgCache::State::ConfigFiles))
+   {
+      if (Ver.end() == true)
+	 _error->Warning("Encountered status field in a non-version description");
+      else
+	 Pkg->CurrentVer = Ver.MapPointer();
+   }
+   
+   return true;
+}
+
+const char *debListParser::ConvertRelation(const char *I,unsigned int &Op)
+{
+   // Determine the operator
+   switch (*I)
+   {
+      case '<':
+      I++;
+      if (*I == '=')
+      {
+	 I++;
+	 Op = pkgCache::Dep::LessEq;
+	 break;
+      }
+      
+      if (*I == '<')
+      {
+	 I++;
+	 Op = pkgCache::Dep::Less;
+	 break;
+      }
+      
+      // < is the same as <= and << is really Cs < for some reason
+      Op = pkgCache::Dep::LessEq;
+      break;
+      
+      case '>':
+      I++;
+      if (*I == '=')
+      {
+	 I++;
+	 Op = pkgCache::Dep::GreaterEq;
+	 break;
+      }
+      
+      if (*I == '>')
+      {
+	 I++;
+	 Op = pkgCache::Dep::Greater;
+	 break;
+      }
+      
+      // > is the same as >= and >> is really Cs > for some reason
+      Op = pkgCache::Dep::GreaterEq;
+      break;
+      
+      case '=':
+      Op = pkgCache::Dep::Equals;
+      I++;
+      break;
+      
+      // HACK around bad package definitions
+      default:
+      Op = pkgCache::Dep::Equals;
+      break;
+   }
+   return I;
+}
+									/*}}}*/
+// ListParser::ParseDepends - Parse a dependency element		/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses the dependency elements out of a standard string in place,
+   bit by bit. */
+const char *debListParser::ParseDepends(const char *Start,const char *Stop,
+					string &Package,string &Ver,
+					unsigned int &Op, bool const &ParseArchFlags,
+					bool const &StripMultiArch,
+					bool const &ParseRestrictionsList,
+				        string const &Arch)
+{
+   StringView PackageView;
+   StringView VerView;
+
+   auto res = ParseDepends(Start, Stop, PackageView, VerView, Op, (bool)ParseArchFlags,
+   (bool) StripMultiArch, (bool) ParseRestrictionsList, Arch);
+   Package = PackageView.to_string();
+   Ver = VerView.to_string();
+
+   return res;
+}
+
+const char *debListParser::ParseDepends(const char *Start, const char *Stop,
+					StringView &Package, StringView &Ver,
+					unsigned int &Op, bool ParseArchFlags,
+					bool StripMultiArch,
+					bool ParseRestrictionsList, string Arch)
+{
+   if (Arch.empty())
+      Arch = _config->Find("APT::Architecture");
+   // Strip off leading space
+   for (;Start != Stop && isspace_ascii(*Start) != 0; ++Start);
+   
+   // Parse off the package name
+   const char *I = Start;
+   for (;I != Stop && isspace_ascii(*I) == 0 && *I != '(' && *I != ')' &&
+	*I != ',' && *I != '|' && *I != '[' && *I != ']' &&
+	*I != '<' && *I != '>'; ++I);
+   
+   // Malformed, no '('
+   if (I != Stop && *I == ')')
+      return 0;
+
+   if (I == Start)
+      return 0;
+   
+   // Stash the package name
+   Package = StringView(Start, I - Start);
+
+   // We don't want to confuse library users which can't handle MultiArch
+   if (StripMultiArch == true) {
+      size_t const found = Package.rfind(':');
+      if (found != StringView::npos &&
+	  (Package.substr(found) == ":any" ||
+	   Package.substr(found) == ":native" ||
+	   Package.substr(found +1) == Arch))
+	 Package = Package.substr(0,found);
+   }
+
+   // Skip white space to the '('
+   for (;I != Stop && isspace_ascii(*I) != 0 ; I++);
+   
+   // Parse a version
+   if (I != Stop && *I == '(')
+   {
+      // Skip the '('
+      for (I++; I != Stop && isspace_ascii(*I) != 0 ; I++);
+      if (I + 3 >= Stop)
+	 return 0;
+      I = ConvertRelation(I,Op);
+      
+      // Skip whitespace
+      for (;I != Stop && isspace_ascii(*I) != 0; I++);
+      Start = I;
+      I = (const char*) memchr(I, ')', Stop - I);
+      if (I == NULL || Start == I)
+	 return 0;
+      
+      // Skip trailing whitespace
+      const char *End = I;
+      for (; End > Start && isspace_ascii(End[-1]); End--);
+      
+      Ver = StringView(Start,End-Start);
+      I++;
+   }
+   else
+   {
+      Ver = StringView();
+      Op = pkgCache::Dep::NoOp;
+   }
+   
+   // Skip whitespace
+   for (;I != Stop && isspace_ascii(*I) != 0; I++);
+
+   if (unlikely(ParseArchFlags == true))
+   {
+      APT::CacheFilter::PackageArchitectureMatchesSpecification matchesArch(Arch, false);
+
+      // Parse an architecture
+      if (I != Stop && *I == '[')
+      {
+	 ++I;
+	 // malformed
+	 if (unlikely(I == Stop))
+	    return 0;
+
+	 const char *End = I;
+	 bool Found = false;
+	 bool NegArch = false;
+	 while (I != Stop)
+	 {
+	    // look for whitespace or ending ']'
+	    for (;End != Stop && !isspace_ascii(*End) && *End != ']'; ++End);
+
+	    if (unlikely(End == Stop))
+	       return 0;
+
+	    if (*I == '!')
+	    {
+	       NegArch = true;
+	       ++I;
+	    }
+
+	    std::string const arch(I, End);
+	    if (arch.empty() == false && matchesArch(arch.c_str()) == true)
+	    {
+	       Found = true;
+	       if (I[-1] != '!')
+		  NegArch = false;
+	       // we found a match, so fast-forward to the end of the wildcards
+	       for (; End != Stop && *End != ']'; ++End);
+	    }
+
+	    if (*End++ == ']') {
+	       I = End;
+	       break;
+	    }
+
+	    I = End;
+	    for (;I != Stop && isspace_ascii(*I) != 0; I++);
+	 }
+
+	 if (NegArch == true)
+	    Found = !Found;
+
+	 if (Found == false)
+	    Package = ""; /* not for this arch */
+      }
+
+      // Skip whitespace
+      for (;I != Stop && isspace_ascii(*I) != 0; I++);
+   }
+
+   if (unlikely(ParseRestrictionsList == true))
+   {
+      // Parse a restrictions formula which is in disjunctive normal form:
+      // (foo AND bar) OR (blub AND bla)
+
+      std::vector<string> const profiles = APT::Configuration::getBuildProfiles();
+
+      // if the next character is a restriction list, then by default the
+      // dependency does not apply and the conditions have to be checked
+      // if the next character is not a restriction list, then by default the
+      // dependency applies
+      bool applies1 = (*I != '<');
+      while (I != Stop)
+      {
+	 if (*I != '<')
+	     break;
+
+	 ++I;
+	 // malformed
+	 if (unlikely(I == Stop))
+	    return 0;
+
+	 const char *End = I;
+
+	 // if of the prior restriction list is already fulfilled, then
+	 // we can just skip to the end of the current list
+	 if (applies1) {
+	    for (;End != Stop && *End != '>'; ++End);
+	    I = ++End;
+	    // skip whitespace
+	    for (;I != Stop && isspace_ascii(*I) != 0; I++);
+	 } else {
+	    bool applies2 = true;
+	    // all the conditions inside a restriction list have to be
+	    // met so once we find one that is not met, we can skip to
+	    // the end of this list
+	    while (I != Stop)
+	    {
+	       // look for whitespace or ending '>'
+	       // End now points to the character after the current term
+	       for (;End != Stop && !isspace_ascii(*End) && *End != '>'; ++End);
+
+	       if (unlikely(End == Stop))
+		  return 0;
+
+	       bool NegRestriction = false;
+	       if (*I == '!')
+	       {
+		  NegRestriction = true;
+		  ++I;
+	       }
+
+	       std::string const restriction(I, End);
+	       if (restriction.empty() == false && profiles.empty() == false &&
+		  std::find(profiles.begin(), profiles.end(), restriction) != profiles.end())
+	       {
+		  if (NegRestriction) {
+		     applies2 = false;
+		     // since one of the terms does not apply we don't have to check the others
+		     for (; End != Stop && *End != '>'; ++End);
+		  }
+	       } else {
+		  if (!NegRestriction) {
+		     applies2 = false;
+		     // since one of the terms does not apply we don't have to check the others
+		     for (; End != Stop && *End != '>'; ++End);
+		  }
+	       }
+
+	       if (*End++ == '>') {
+		  I = End;
+		  // skip whitespace
+		  for (;I != Stop && isspace_ascii(*I) != 0; I++);
+		  break;
+	       }
+
+	       I = End;
+	       // skip whitespace
+	       for (;I != Stop && isspace_ascii(*I) != 0; I++);
+	    }
+	    if (applies2) {
+	       applies1 = true;
+	    }
+	 }
+      }
+
+      if (applies1 == false) {
+	 Package = ""; //not for this restriction
+      }
+   }
+
+   if (I != Stop && *I == '|')
+      Op |= pkgCache::Dep::Or;
+   
+   if (I == Stop || *I == ',' || *I == '|')
+   {
+      if (I != Stop)
+	 for (I++; I != Stop && isspace_ascii(*I) != 0; I++);
+      return I;
+   }
+   
+   return 0;
+}
+									/*}}}*/
+// ListParser::ParseDepends - Parse a dependency list			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the higher level depends parser. It takes a tag and generates
+   a complete depends tree for the given version. */
+bool debListParser::ParseDepends(pkgCache::VerIterator &Ver,
+				 pkgTagSection::Key Key,unsigned int Type)
+{
+   const char *Start;
+   const char *Stop;
+   if (Section.Find(Key,Start,Stop) == false || Start == Stop)
+      return true;
+
+   string const pkgArch = Ver.Arch();
+   bool const barbarianArch = not APT::Configuration::checkArchitecture(pkgArch);
+
+   while (1)
+   {
+      StringView Package;
+      StringView Version;
+      unsigned int Op;
+
+      Start = ParseDepends(Start, Stop, Package, Version, Op, false, false, false, myArch);
+      if (Start == 0)
+	 return _error->Error("Problem parsing dependency %zu of %s:%s=%s", static_cast<size_t>(Key), // TODO
+			      Ver.ParentPkg().Name(), Ver.Arch(), Ver.VerStr());
+      size_t const found = Package.rfind(':');
+
+      if (found == string::npos)
+      {
+	 if (NewDepends(Ver,Package,pkgArch,Version,Op,Type) == false)
+	    return false;
+      }
+      else if (Package.substr(found) == ":any")
+      {
+	 if (barbarianArch)
+	 {
+	    if (not NewDepends(Ver, Package, "any", Version, Op | pkgCache::Dep::Or, Type))
+	       return false;
+	    if (not NewDepends(Ver, Package.substr(0, found), pkgArch, Version, Op, Type))
+	       return false;
+	 }
+	 else if (not NewDepends(Ver, Package, "any", Version, Op, Type))
+	    return false;
+      }
+      else
+      {
+	 // Such dependencies are not supposed to be accepted …
+	 // … but this is probably the best thing to do anyway
+	 if (Package.substr(found + 1) == "native")
+	 {
+	    std::string const Pkg = Package.substr(0, found).to_string() + ':' + Ver.Cache()->NativeArch();
+	    if (NewDepends(Ver, Pkg, "any", Version, Op | pkgCache::Dep::ArchSpecific, Type) == false)
+	       return false;
+	 }
+	 else if (NewDepends(Ver, Package, "any", Version, Op | pkgCache::Dep::ArchSpecific, Type) == false)
+	    return false;
+      }
+
+      if (Start == Stop)
+	 break;
+   }
+   return true;
+}
+									/*}}}*/
+// ListParser::ParseProvides - Parse the provides list			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debListParser::ParseProvides(pkgCache::VerIterator &Ver)
+{
+   /* it is unlikely, but while parsing dependencies, we might have already
+      picked up multi-arch implicit provides which we do not want to duplicate here */
+   bool hasProvidesAlready = false;
+   std::string const spzName = Ver.ParentPkg().FullName(false);
+   {
+      for (pkgCache::PrvIterator Prv = Ver.ProvidesList(); Prv.end() == false; ++Prv)
+      {
+	 if (Prv.IsMultiArchImplicit() == false || (Prv->Flags & pkgCache::Flag::ArchSpecific) == 0)
+	    continue;
+	 if (spzName != Prv.OwnerPkg().FullName(false))
+	    continue;
+	 hasProvidesAlready = true;
+	 break;
+      }
+   }
+
+   string const Arch = Ver.Arch();
+   bool const barbarianArch = not APT::Configuration::checkArchitecture(Arch);
+   const char *Start;
+   const char *Stop;
+   if (Section.Find(pkgTagSection::Key::Provides,Start,Stop) == true)
+   {
+      StringView Package;
+      StringView Version;
+      unsigned int Op;
+
+      do
+      {
+	 Start = ParseDepends(Start,Stop,Package,Version,Op, false, false, false);
+	 const size_t archfound = Package.rfind(':');
+	 if (Start == 0)
+	    return _error->Error("Problem parsing Provides line of %s:%s=%s", Ver.ParentPkg().Name(), Ver.Arch(), Ver.VerStr());
+	 if (unlikely(Op != pkgCache::Dep::NoOp && Op != pkgCache::Dep::Equals)) {
+	    _error->Warning("Ignoring non-equal Provides for package %s in %s:%s=%s", Package.to_string().c_str(), Ver.ParentPkg().Name(), Ver.Arch(), Ver.VerStr());
+	 } else if (archfound != string::npos) {
+	    StringView spzArch = Package.substr(archfound + 1);
+	    if (spzArch != "any")
+	    {
+	       if (NewProvides(Ver, Package.substr(0, archfound), spzArch, Version, pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific) == false)
+		  return false;
+	    }
+	    if (NewProvides(Ver, Package, "any", Version, pkgCache::Flag::ArchSpecific) == false)
+	       return false;
+	 } else if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign) {
+	    if (not barbarianArch)
+	    {
+	       if (NewProvidesAllArch(Ver, Package, Version, 0) == false)
+		  return false;
+	    }
+	    else if (NewProvides(Ver, Package, Arch, Version, 0) == false)
+	       return false;
+	 } else {
+	    if ((Ver->MultiArch & pkgCache::Version::Allowed) == pkgCache::Version::Allowed && not barbarianArch)
+	    {
+	       if (NewProvides(Ver, Package.to_string().append(":any"), "any", Version, pkgCache::Flag::MultiArchImplicit) == false)
+		  return false;
+	    }
+	    if (NewProvides(Ver, Package, Arch, Version, 0) == false)
+	       return false;
+	 }
+	 if (archfound == std::string::npos)
+	 {
+	    string spzName = Package.to_string();
+	    spzName.push_back(':');
+	    spzName.append(Ver.ParentPkg().Arch());
+	    pkgCache::PkgIterator const spzPkg = Ver.Cache()->FindPkg(spzName, "any");
+	    if (spzPkg.end() == false)
+	    {
+	       if (NewProvides(Ver, spzName, "any", Version, pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific) == false)
+		  return false;
+	    }
+	 }
+      } while (Start != Stop);
+   }
+
+   if (not barbarianArch)
+   {
+      if ((Ver->MultiArch & pkgCache::Version::Allowed) == pkgCache::Version::Allowed)
+      {
+	 string const Package = string(Ver.ParentPkg().Name()).append(":").append("any");
+	 if (NewProvides(Ver, Package, "any", Ver.VerStr(), pkgCache::Flag::MultiArchImplicit) == false)
+	    return false;
+      }
+      else if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign)
+      {
+	 if (NewProvidesAllArch(Ver, Ver.ParentPkg().Name(), Ver.VerStr(), pkgCache::Flag::MultiArchImplicit) == false)
+	    return false;
+      }
+   }
+
+   if (hasProvidesAlready == false)
+   {
+      pkgCache::PkgIterator const spzPkg = Ver.Cache()->FindPkg(spzName, "any");
+      if (spzPkg.end() == false)
+      {
+	 if (NewProvides(Ver, spzName, "any", Ver.VerStr(), pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific) == false)
+	    return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// ListParser::GrabWord - Matches a word and returns			/*{{{*/
+// ---------------------------------------------------------------------
+/* Looks for a word in a list of words - for ParseStatus */
+bool debListParser::GrabWord(StringView Word, WordList const *List, unsigned char &Out)
+{
+   for (unsigned int C = 0; List[C].Str.empty() == false; C++)
+   {
+      if (Word.length() == List[C].Str.length() &&
+	  strncasecmp(Word.data(), List[C].Str.data(), Word.length()) == 0)
+      {
+	 Out = List[C].Val;
+	 return true;
+      }
+   }
+   return false;
+}
+									/*}}}*/
+// ListParser::Step - Move to the next section in the file		/*{{{*/
+// ---------------------------------------------------------------------
+/* This has to be careful to only process the correct architecture */
+bool debListParser::Step()
+{
+   iOffset = Tags.Offset();
+   return Tags.Step(Section);
+}
+									/*}}}*/
+// ListParser::GetPrio - Convert the priority from a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned char debListParser::GetPrio(string Str)
+{
+   unsigned char Out;
+   if (GrabWord(Str,PrioList,Out) == false)
+      Out = pkgCache::State::Extra;
+   
+   return Out;
+}
+									/*}}}*/
+bool debListParser::SameVersion(uint32_t Hash,		/*{{{*/
+      pkgCache::VerIterator const &Ver)
+{
+   if (pkgCacheListParser::SameVersion(Hash, Ver) == false)
+      return false;
+   // status file has no (Download)Size, but all others are fair game
+   // status file is parsed last, so the first version we encounter is
+   // probably also the version we have downloaded
+   unsigned long long const Size = Section.FindULL(pkgTagSection::Key::Size);
+   if (Size != 0 && Ver->Size != 0 && Size != Ver->Size)
+      return false;
+   // available everywhere, but easier to check here than to include in VersionHash
+   unsigned char MultiArch = ParseMultiArch(false);
+   if (MultiArch != Ver->MultiArch)
+      return false;
+   // for all practical proposes (we can check): same version
+   return true;
+}
+									/*}}}*/
+
+debDebFileParser::debDebFileParser(FileFd *File, std::string const &DebFile)
+   : debListParser(File), DebFile(DebFile)
+{
+}
+
+bool debDebFileParser::UsePackage(pkgCache::PkgIterator &Pkg,
+                                  pkgCache::VerIterator &Ver)
+{
+   if (not debListParser::UsePackage(Pkg, Ver))
+      return false;
+   // we use the full file path as a provides so that the file is found by its name
+   // using the MultiArchImplicit flag for this is a bit of a stretch
+   return NewProvides(Ver, DebFile, Pkg.Cache()->NativeArch(), Ver.VerStr(), pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific);
+}
+
+debListParser::~debListParser() {}
diff --git a/apt-pkg/deb/deblistparser.h b/apt-pkg/deb/deblistparser.h
new file mode 100644
index 0000000..eefce2a
--- /dev/null
+++ b/apt-pkg/deb/deblistparser.h
@@ -0,0 +1,124 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Debian Package List Parser - This implements the abstract parser 
+   interface for Debian package files
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBLISTPARSER_H
+#define PKGLIB_DEBLISTPARSER_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/tagfile.h>
+
+#include <string>
+#include <vector>
+#include <apt-pkg/string_view.h>
+
+
+class FileFd;
+
+class APT_HIDDEN debListParser : public pkgCacheListParser
+{
+   public:
+
+   // Parser Helper
+   struct WordList
+   {
+      APT::StringView Str;
+      unsigned char Val;
+   };
+
+   private:
+   std::vector<std::string> forceEssential;
+   std::vector<std::string> forceImportant;
+   std::string MD5Buffer;
+   std::string myArch;
+
+   protected:
+   pkgTagFile Tags;
+   pkgTagSection Section;
+   map_filesize_t iOffset;
+
+   virtual bool ParseStatus(pkgCache::PkgIterator &Pkg,pkgCache::VerIterator &Ver);
+   bool ParseDepends(pkgCache::VerIterator &Ver, pkgTagSection::Key Key,
+		     unsigned int Type);
+   bool ParseProvides(pkgCache::VerIterator &Ver);
+
+   APT_HIDDEN static bool GrabWord(APT::StringView Word,const WordList *List,unsigned char &Out);
+   APT_HIDDEN unsigned char ParseMultiArch(bool const showErrors);
+
+   public:
+
+   APT_PUBLIC static unsigned char GetPrio(std::string Str);
+      
+   // These all operate against the current section
+   virtual std::string Package() APT_OVERRIDE;
+   virtual bool ArchitectureAll() APT_OVERRIDE;
+   virtual APT::StringView Architecture() APT_OVERRIDE;
+   virtual APT::StringView Version() APT_OVERRIDE;
+   virtual bool NewVersion(pkgCache::VerIterator &Ver) APT_OVERRIDE;
+   virtual std::vector<std::string> AvailableDescriptionLanguages() APT_OVERRIDE;
+   virtual APT::StringView Description_md5() APT_OVERRIDE;
+   virtual uint32_t VersionHash() APT_OVERRIDE;
+   virtual bool SameVersion(uint32_t Hash, pkgCache::VerIterator const &Ver) APT_OVERRIDE;
+   virtual bool UsePackage(pkgCache::PkgIterator &Pkg,
+			   pkgCache::VerIterator &Ver) APT_OVERRIDE;
+   virtual map_filesize_t Offset() APT_OVERRIDE {return iOffset;};
+   virtual map_filesize_t Size() APT_OVERRIDE {return Section.size();};
+
+   virtual bool Step() APT_OVERRIDE;
+
+   APT_PUBLIC static const char *ParseDepends(const char *Start, const char *Stop,
+					      std::string &Package, std::string &Ver, unsigned int &Op,
+					      bool const &ParseArchFlags = false, bool const &StripMultiArch = true,
+					      bool const &ParseRestrictionsList = false,
+					      std::string const &Arch = "");
+
+   APT_PUBLIC static const char *ParseDepends(const char *Start, const char *Stop,
+					      APT::StringView &Package,
+					      APT::StringView &Ver, unsigned int &Op,
+					      bool const ParseArchFlags = false, bool StripMultiArch = true,
+					      bool const ParseRestrictionsList = false,
+					      std::string Arch = "");
+
+   APT_PUBLIC static const char *ConvertRelation(const char *I,unsigned int &Op);
+
+   explicit debListParser(FileFd *File);
+   virtual ~debListParser();
+};
+
+class APT_HIDDEN debDebFileParser : public debListParser
+{
+ private:
+   std::string DebFile;
+
+ public:
+   debDebFileParser(FileFd *File, std::string const &DebFile);
+   virtual bool UsePackage(pkgCache::PkgIterator &Pkg,
+			   pkgCache::VerIterator &Ver) APT_OVERRIDE;
+};
+
+class APT_HIDDEN debTranslationsParser : public debListParser
+{
+ public:
+   // a translation can never be a real package
+   virtual APT::StringView Architecture() APT_OVERRIDE { return ""; }
+   virtual APT::StringView Version() APT_OVERRIDE { return ""; }
+
+   explicit debTranslationsParser(FileFd *File)
+      : debListParser(File) {};
+};
+
+class APT_HIDDEN debStatusListParser : public debListParser
+{
+ public:
+   virtual bool ParseStatus(pkgCache::PkgIterator &Pkg,pkgCache::VerIterator &Ver) APT_OVERRIDE;
+   explicit debStatusListParser(FileFd *File)
+      : debListParser(File) {};
+};
+#endif
diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
new file mode 100644
index 0000000..c6005f1
--- /dev/null
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -0,0 +1,1346 @@
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debindexfile.h>
+#include <apt-pkg/debmetaindex.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <map>
+#include <optional>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <string.h>
+#include <sys/stat.h>
+
+#include <apti18n.h>
+
+static std::string transformFingergrpints(std::string finger) /*{{{*/
+{
+   std::transform(finger.begin(), finger.end(), finger.begin(), ::toupper);
+   if (finger.length() == 40)
+   {
+      if (finger.find_first_not_of("0123456789ABCDEF") == std::string::npos)
+	 return finger;
+   }
+   else if (finger.length() == 41)
+   {
+      auto bang = finger.find_first_not_of("0123456789ABCDEF");
+      if (bang == 40 && finger[bang] == '!')
+	 return finger;
+   }
+   return "";
+}
+									/*}}}*/
+static std::string transformFingergrpintsWithFilenames(std::string const &finger) /*{{{*/
+{
+   // no check for existence as we could be chrooting later or such things
+   if (finger.empty() == false && finger[0] == '/')
+      return finger;
+   return transformFingergrpints(finger);
+}
+									/*}}}*/
+// Introducer is set if additional keys may be introduced, for example	/*{{{*/
+// by setting it to a filename or a complete key
+static std::string NormalizeSignedBy(std::string SignedBy, bool const Introducer)
+{
+   // This is an embedded public pgp key, normalize spaces inside it and empty "." lines
+   if (Introducer && SignedBy.find("-----BEGIN PGP PUBLIC KEY BLOCK-----") != std::string::npos) {
+      std::istringstream is(SignedBy);
+      std::ostringstream os;
+      std::string line;
+
+      while (std::getline(is, line)) {
+	 line = APT::String::Strip(line);
+	 // The special encoding for empty lines in deb822
+	 if (line == ".")
+	    line="";
+	 os << line << std::endl;
+      }
+      return os.str();
+   }
+
+   // we could go all fancy and allow short/long/string matches as gpgv/apt-key does,
+   // but fingerprints are harder to fake than the others and this option is set once,
+   // not interactively all the time so easy to type is not really a concern.
+   std::transform(SignedBy.begin(), SignedBy.end(), SignedBy.begin(), [](char const c) {
+      return (isspace_ascii(c) == 0) ? c : ',';
+   });
+   auto fingers = VectorizeString(SignedBy, ',');
+   auto const isAnEmptyString = [](std::string const &s) { return s.empty(); };
+   fingers.erase(std::remove_if(fingers.begin(), fingers.end(), isAnEmptyString), fingers.end());
+   if (unlikely(fingers.empty()))
+      return "";
+   if (Introducer)
+      std::transform(fingers.begin(), fingers.end(), fingers.begin(), transformFingergrpintsWithFilenames);
+   else
+      std::transform(fingers.begin(), fingers.end(), fingers.begin(), transformFingergrpints);
+   if (std::any_of(fingers.begin(), fingers.end(), isAnEmptyString))
+      return "";
+   std::stringstream os;
+   std::copy(fingers.begin(), fingers.end() - 1, std::ostream_iterator<std::string>(os, ","));
+   os << *fingers.rbegin();
+   return os.str();
+}
+									/*}}}*/
+
+class APT_HIDDEN debReleaseIndexPrivate					/*{{{*/
+{
+   public:
+   struct APT_HIDDEN debSectionEntry
+   {
+      std::string const sourcesEntry;
+      std::string const Name;
+      std::vector<std::string> const Targets;
+      std::vector<std::string> const Architectures;
+      std::vector<std::string> const Languages;
+      bool const UsePDiffs;
+      std::string const UseByHash;
+   };
+
+   std::vector<debSectionEntry> DebEntries;
+   std::vector<debSectionEntry> DebSrcEntries;
+
+   metaIndex::TriState CheckValidUntil;
+   time_t ValidUntilMin;
+   time_t ValidUntilMax;
+
+   metaIndex::TriState CheckDate;
+   time_t DateMaxFuture;
+   time_t NotBefore;
+
+   std::vector<std::string> Architectures;
+   std::vector<std::string> NoSupportForAll;
+   std::vector<std::string> SupportedComponents;
+   std::map<std::string, std::string> const ReleaseOptions;
+
+   explicit debReleaseIndexPrivate(std::map<std::string, std::string> const &Options) : CheckValidUntil(metaIndex::TRI_UNSET), ValidUntilMin(0), ValidUntilMax(0), CheckDate(metaIndex::TRI_UNSET), DateMaxFuture(0), NotBefore(0), ReleaseOptions(Options) {}
+};
+									/*}}}*/
+// ReleaseIndex::MetaIndex* - display helpers				/*{{{*/
+std::string debReleaseIndex::MetaIndexInfo(const char *Type) const
+{
+   std::string Info = ::URI::ArchiveOnly(URI) + ' ';
+   if (Dist[Dist.size() - 1] == '/')
+   {
+      if (Dist != "/")
+	 Info += Dist;
+   }
+   else
+      Info += Dist;
+   Info += " ";
+   Info += Type;
+   return Info;
+}
+std::string debReleaseIndex::Describe() const
+{
+   return MetaIndexInfo("Release");
+}
+
+std::string debReleaseIndex::MetaIndexFile(const char *Type) const
+{
+   return _config->FindDir("Dir::State::lists") +
+      URItoFileName(MetaIndexURI(Type));
+}
+static std::string constructMetaIndexURI(std::string URI, std::string const &Dist, char const * const Type)
+{
+   if (Dist == "/")
+      ;
+   else if (Dist[Dist.size()-1] == '/')
+      URI += pkgAcquire::URIEncode(Dist);
+   else
+      URI += "dists/" + pkgAcquire::URIEncode(Dist) + "/";
+   return URI + pkgAcquire::URIEncode(Type);
+}
+std::string debReleaseIndex::MetaIndexURI(const char *Type) const
+{
+   return constructMetaIndexURI(URI, Dist, Type);
+}
+									/*}}}*/
+// ReleaseIndex Con- and Destructors					/*{{{*/
+debReleaseIndex::debReleaseIndex(std::string const &URI, std::string const &Dist, std::map<std::string, std::string> const &Options) :
+					metaIndex(URI, Dist, "deb"), d(new debReleaseIndexPrivate(Options))
+{}
+debReleaseIndex::debReleaseIndex(std::string const &URI, std::string const &Dist, bool const pTrusted, std::map<std::string, std::string> const &Options) :
+					metaIndex(URI, Dist, "deb"), d(new debReleaseIndexPrivate(Options))
+{
+   Trusted = pTrusted ? TRI_YES : TRI_NO;
+}
+debReleaseIndex::~debReleaseIndex() {
+   if (d != NULL)
+      delete d;
+}
+									/*}}}*/
+// ReleaseIndex::GetIndexTargets					/*{{{*/
+static void GetIndexTargetsFor(char const * const Type, std::string const &URI, std::string const &Dist,
+      std::vector<debReleaseIndexPrivate::debSectionEntry> const &entries,
+      std::vector<IndexTarget> &IndexTargets, std::map<std::string, std::string> const &ReleaseOptions)
+{
+   bool const flatArchive = (Dist[Dist.length() - 1] == '/');
+   std::string const baseURI = constructMetaIndexURI(URI, Dist, "");
+
+   std::string DefCompressionTypes;
+   {
+      std::vector<std::string> types = APT::Configuration::getCompressionTypes();
+      if (types.empty() == false)
+      {
+	 std::ostringstream os;
+	 std::copy(types.begin(), types.end()-1, std::ostream_iterator<std::string>(os, " "));
+	 os << *types.rbegin();
+	 DefCompressionTypes = os.str();
+      }
+   }
+   std::string DefKeepCompressedAs;
+   {
+      std::vector<APT::Configuration::Compressor> comps = APT::Configuration::getCompressors();
+      if (comps.empty() == false)
+      {
+	 std::sort(comps.begin(), comps.end(),
+	       [](APT::Configuration::Compressor const &a, APT::Configuration::Compressor const &b) { return a.Cost < b.Cost; });
+	 std::ostringstream os;
+	 for (auto const &c : comps)
+	    if (c.Cost != 0)
+	       os << c.Extension.substr(1) << ' ';
+	 DefKeepCompressedAs = os.str();
+      }
+      DefKeepCompressedAs += "uncompressed";
+   }
+
+   std::vector<std::string> const NativeArchs = { _config->Find("APT::Architecture"), "implicit:all" };
+   bool const GzipIndex = _config->FindB("Acquire::GzipIndexes", false);
+   for (std::vector<debReleaseIndexPrivate::debSectionEntry>::const_iterator E = entries.begin(); E != entries.end(); ++E)
+   {
+      for (std::vector<std::string>::const_iterator T = E->Targets.begin(); T != E->Targets.end(); ++T)
+      {
+#define APT_T_CONFIG_STR(X, Y) _config->Find(std::string("Acquire::IndexTargets::") + Type  + "::" + *T + "::" + (X), (Y))
+#define APT_T_CONFIG_BOOL(X, Y) _config->FindB(std::string("Acquire::IndexTargets::") + Type  + "::" + *T + "::" + (X), (Y))
+	 std::string const tplMetaKey = APT_T_CONFIG_STR(flatArchive ? "flatMetaKey" : "MetaKey", "");
+	 std::string const tplShortDesc = APT_T_CONFIG_STR("ShortDescription", "");
+	 std::string const tplLongDesc = "$(SITE) " + APT_T_CONFIG_STR(flatArchive ? "flatDescription" : "Description", "");
+	 std::string const tplIdentifier = APT_T_CONFIG_STR("Identifier", *T);
+	 bool const IsOptional = APT_T_CONFIG_BOOL("Optional", true);
+	 bool const KeepCompressed = APT_T_CONFIG_BOOL("KeepCompressed", GzipIndex);
+	 bool const DefaultEnabled = APT_T_CONFIG_BOOL("DefaultEnabled", true);
+	 bool const UsePDiffs = APT_T_CONFIG_BOOL("PDiffs", E->UsePDiffs);
+	 std::string const UseByHash = APT_T_CONFIG_STR("By-Hash", E->UseByHash);
+	 std::string const CompressionTypes = APT_T_CONFIG_STR("CompressionTypes", DefCompressionTypes);
+	 std::string KeepCompressedAs = APT_T_CONFIG_STR("KeepCompressedAs", "");
+	 std::string const FallbackOf = APT_T_CONFIG_STR("Fallback-Of", "");
+#undef APT_T_CONFIG_BOOL
+#undef APT_T_CONFIG_STR
+	 if (tplMetaKey.empty())
+	    continue;
+
+	 if (KeepCompressedAs.empty())
+	    KeepCompressedAs = DefKeepCompressedAs;
+	 else
+	 {
+	    std::vector<std::string> const defKeep = VectorizeString(DefKeepCompressedAs, ' ');
+	    std::vector<std::string> const valKeep = VectorizeString(KeepCompressedAs, ' ');
+	    std::vector<std::string> keep;
+	    for (auto const &val : valKeep)
+	    {
+	       if (val.empty())
+		  continue;
+	       if (std::find(defKeep.begin(), defKeep.end(), val) == defKeep.end())
+		  continue;
+	       keep.push_back(val);
+	    }
+	    if (std::find(keep.begin(), keep.end(), "uncompressed") == keep.end())
+	       keep.push_back("uncompressed");
+	    std::ostringstream os;
+	    std::copy(keep.begin(), keep.end()-1, std::ostream_iterator<std::string>(os, " "));
+	    os << *keep.rbegin();
+	    KeepCompressedAs = os.str();
+	 }
+
+	 for (std::vector<std::string>::const_iterator L = E->Languages.begin(); L != E->Languages.end(); ++L)
+	 {
+	    if (*L == "none" && tplMetaKey.find("$(LANGUAGE)") != std::string::npos)
+	       continue;
+
+	    for (std::vector<std::string>::const_iterator A = E->Architectures.begin(); A != E->Architectures.end(); ++A)
+	    {
+	       for (auto const &NativeArch: NativeArchs)
+	       {
+		  constexpr static auto BreakPoint = "$(NATIVE_ARCHITECTURE)";
+		  // available in templates
+		  std::map<std::string, std::string> Options;
+		  Options.insert(ReleaseOptions.begin(), ReleaseOptions.end());
+		  if (tplMetaKey.find("$(COMPONENT)") != std::string::npos)
+		     Options.emplace("COMPONENT", E->Name);
+		  if (tplMetaKey.find("$(LANGUAGE)") != std::string::npos)
+		     Options.emplace("LANGUAGE", *L);
+		  if (tplMetaKey.find("$(ARCHITECTURE)") != std::string::npos)
+		     Options.emplace("ARCHITECTURE", (*A == "implicit:all") ? "all" : *A);
+		  else if (tplMetaKey.find("$(NATIVE_ARCHITECTURE)") != std::string::npos)
+		     Options.emplace("ARCHITECTURE", (NativeArch == "implicit:all") ? "all" : NativeArch);
+		  if (tplMetaKey.find("$(NATIVE_ARCHITECTURE)") != std::string::npos)
+		     Options.emplace("NATIVE_ARCHITECTURE", (NativeArch == "implicit:all") ? "all" : NativeArch);
+
+		  std::string MetaKey = tplMetaKey;
+		  std::string ShortDesc = tplShortDesc;
+		  std::string LongDesc = tplLongDesc;
+		  std::string Identifier = tplIdentifier;
+		  for (std::map<std::string, std::string>::const_iterator O = Options.begin(); O != Options.end(); ++O)
+		  {
+		     std::string const varname = "$(" + O->first + ")";
+		     MetaKey = SubstVar(MetaKey, varname, O->second);
+		     ShortDesc = SubstVar(ShortDesc, varname, O->second);
+		     LongDesc = SubstVar(LongDesc, varname, O->second);
+		     Identifier = SubstVar(Identifier, varname, O->second);
+		  }
+
+		  {
+		     auto const dup = std::find_if(IndexTargets.begin(), IndexTargets.end(), [&](IndexTarget const &IT) {
+			return MetaKey == IT.MetaKey && baseURI == IT.Option(IndexTarget::BASE_URI) &&
+			   E->sourcesEntry == IT.Option(IndexTarget::SOURCESENTRY) && *T == IT.Option(IndexTarget::CREATED_BY);
+		     });
+		     if (dup != IndexTargets.end())
+		     {
+			if (tplMetaKey.find(BreakPoint) == std::string::npos)
+			   break;
+			continue;
+		     }
+		  }
+
+		  {
+		     auto const dup = std::find_if(IndexTargets.begin(), IndexTargets.end(), [&](IndexTarget const &IT) {
+			return MetaKey == IT.MetaKey && baseURI == IT.Option(IndexTarget::BASE_URI) &&
+			   E->sourcesEntry == IT.Option(IndexTarget::SOURCESENTRY) && *T != IT.Option(IndexTarget::CREATED_BY);
+			});
+		     if (dup != IndexTargets.end())
+		     {
+			std::string const dupT = dup->Option(IndexTarget::CREATED_BY);
+			std::string const dupEntry = dup->Option(IndexTarget::SOURCESENTRY);
+			//TRANSLATOR: an identifier like Packages; Releasefile key indicating
+			// a file like main/binary-amd64/Packages; another identifier like Contents;
+			// filename and linenumber of the sources.list entry currently parsed
+			_error->Warning(_("Target %s wants to acquire the same file (%s) as %s from source %s"),
+			      T->c_str(), MetaKey.c_str(), dupT.c_str(), dupEntry.c_str());
+			if (tplMetaKey.find(BreakPoint) == std::string::npos)
+			   break;
+			continue;
+		     }
+		  }
+
+		  {
+		     auto const dup = std::find_if(IndexTargets.begin(), IndexTargets.end(), [&](IndexTarget const &T) {
+			return MetaKey == T.MetaKey && baseURI == T.Option(IndexTarget::BASE_URI) &&
+			   E->sourcesEntry != T.Option(IndexTarget::SOURCESENTRY);
+		     });
+		     if (dup != IndexTargets.end())
+		     {
+			std::string const dupEntry = dup->Option(IndexTarget::SOURCESENTRY);
+			if (T->find("legacy") == std::string::npos)
+			{
+			   //TRANSLATOR: an identifier like Packages; Releasefile key indicating
+			   // a file like main/binary-amd64/Packages; filename and linenumber of
+			   // two sources.list entries
+			   _error->Warning(_("Target %s (%s) is configured multiple times in %s and %s"),
+					   T->c_str(), MetaKey.c_str(), dupEntry.c_str(), E->sourcesEntry.c_str());
+			}
+			if (tplMetaKey.find(BreakPoint) == std::string::npos)
+			   break;
+			continue;
+		     }
+		  }
+
+		  // not available in templates, but in the indextarget
+		  Options.insert(std::make_pair("IDENTIFIER", Identifier));
+		  Options.insert(std::make_pair("TARGET_OF", Type));
+		  Options.insert(std::make_pair("CREATED_BY", *T));
+		  Options.insert(std::make_pair("FALLBACK_OF", FallbackOf));
+		  Options.insert(std::make_pair("PDIFFS", UsePDiffs ? "yes" : "no"));
+		  Options.insert(std::make_pair("BY_HASH", UseByHash));
+		  Options.insert(std::make_pair("DEFAULTENABLED", DefaultEnabled ? "yes" : "no"));
+		  Options.insert(std::make_pair("COMPRESSIONTYPES", CompressionTypes));
+		  Options.insert(std::make_pair("KEEPCOMPRESSEDAS", KeepCompressedAs));
+		  Options.insert(std::make_pair("SOURCESENTRY", E->sourcesEntry));
+
+		  bool IsOpt = IsOptional;
+		  {
+		     auto const arch = Options.find("ARCHITECTURE");
+		     if (arch != Options.end() && arch->second == "all")
+		     {
+			// one of them must be implicit:all then
+			if (*A != "all" && NativeArch != "all")
+			   IsOpt = true;
+			else // user used arch=all explicitly
+			   Options.emplace("Force-Support-For-All", "yes");
+		     }
+		  }
+
+		  IndexTarget Target(
+			MetaKey,
+			ShortDesc,
+			LongDesc,
+			baseURI + MetaKey,
+			IsOpt,
+			KeepCompressed,
+			Options
+			);
+		  IndexTargets.push_back(Target);
+
+		  if (tplMetaKey.find(BreakPoint) == std::string::npos)
+		     break;
+	       }
+
+	       if (tplMetaKey.find("$(ARCHITECTURE)") == std::string::npos)
+		  break;
+
+	    }
+
+	    if (tplMetaKey.find("$(LANGUAGE)") == std::string::npos)
+	       break;
+
+	 }
+
+      }
+   }
+}
+std::vector<IndexTarget> debReleaseIndex::GetIndexTargets() const
+{
+   std::vector<IndexTarget> IndexTargets;
+   GetIndexTargetsFor("deb-src", URI, Dist, d->DebSrcEntries, IndexTargets, d->ReleaseOptions);
+   GetIndexTargetsFor("deb", URI, Dist, d->DebEntries, IndexTargets, d->ReleaseOptions);
+   return IndexTargets;
+}
+									/*}}}*/
+void debReleaseIndex::AddComponent(std::string const &sourcesEntry,	/*{{{*/
+	 bool const isSrc, std::string const &Name,
+	 std::vector<std::string> const &Targets,
+	 std::vector<std::string> const &Architectures,
+	 std::vector<std::string> Languages,
+	 bool const usePDiffs, std::string const &useByHash)
+{
+   if (Languages.empty() == true)
+      Languages.push_back("none");
+   debReleaseIndexPrivate::debSectionEntry const entry = {
+      sourcesEntry, Name, Targets, Architectures, Languages, usePDiffs, useByHash
+   };
+   if (isSrc)
+      d->DebSrcEntries.push_back(entry);
+   else
+      d->DebEntries.push_back(entry);
+}
+									/*}}}*/
+std::string debReleaseIndex::ArchiveURI(std::string const &File) const	/*{{{*/
+{
+   if (File.empty())
+      return URI;
+   return URI + pkgAcquire::URIEncode(File);
+}
+									/*}}}*/
+
+bool debReleaseIndex::Load(std::string const &Filename, std::string * const ErrorText)/*{{{*/
+{
+   LoadedSuccessfully = TRI_NO;
+   FileFd Fd;
+   if (OpenMaybeClearSignedFile(Filename, Fd) == false)
+      return false;
+
+   pkgTagFile TagFile(&Fd, Fd.Size());
+   if (Fd.IsOpen() == false || Fd.Failed())
+   {
+      if (ErrorText != NULL)
+	 strprintf(*ErrorText, _("Unable to parse Release file %s"),Filename.c_str());
+      return false;
+   }
+
+   pkgTagSection Section;
+   const char *Start, *End;
+   if (TagFile.Step(Section) == false)
+   {
+      if (ErrorText != NULL)
+	 strprintf(*ErrorText, _("No sections in Release file %s"), Filename.c_str());
+      return false;
+   }
+   // FIXME: find better tag name
+   SupportsAcquireByHash = Section.FindB("Acquire-By-Hash", false);
+
+   Origin = Section.FindS("Origin");
+   Label = Section.FindS("Label");
+   Version = Section.FindS("Version");
+   Suite = Section.FindS("Suite");
+   Codename = Section.FindS("Codename");
+   ReleaseNotes = Section.FindS("Release-Notes");
+   {
+      std::string const archs = Section.FindS("Architectures");
+      if (archs.empty() == false)
+	 d->Architectures = VectorizeString(archs, ' ');
+   }
+   {
+      std::string const targets = Section.FindS("No-Support-for-Architecture-all");
+      if (targets.empty() == false)
+	 d->NoSupportForAll = VectorizeString(targets, ' ');
+   }
+   for (auto const &comp: VectorizeString(Section.FindS("Components"), ' '))
+   {
+      if (comp.empty())
+	 continue;
+      auto const pos = comp.find_last_of('/');
+      if (pos != std::string::npos) // e.g. security.debian.org uses this style
+	 d->SupportedComponents.push_back(comp.substr(pos + 1));
+      d->SupportedComponents.push_back(std::move(comp));
+   }
+   {
+      decltype(pkgCache::ReleaseFile::Flags) flags = 0;
+      Section.FindFlag("NotAutomatic", flags, pkgCache::Flag::NotAutomatic);
+      signed short defaultpin = 500;
+      if ((flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
+      {
+	 Section.FindFlag("ButAutomaticUpgrades", flags, pkgCache::Flag::ButAutomaticUpgrades);
+	 if ((flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
+	    defaultpin = 100;
+	 else
+	    defaultpin = 1;
+      }
+      DefaultPin = defaultpin;
+   }
+
+   bool FoundHashSum = false;
+   bool FoundStrongHashSum = false;
+   for (auto const hashinfo : HashString::SupportedHashesInfo())
+   {
+      if (not Section.Find(hashinfo.namekey, Start, End))
+	 continue;
+
+      std::string Name;
+      std::string Hash;
+      unsigned long long Size;
+      while (Start < End)
+      {
+	 if (!parseSumData(Start, End, Name, Hash, Size))
+	    return false;
+
+	 HashString const hs(hashinfo.name.to_string(), Hash);
+         if (Entries.find(Name) == Entries.end())
+         {
+            metaIndex::checkSum *Sum = new metaIndex::checkSum;
+            Sum->MetaKeyFilename = Name;
+            Sum->Size = Size;
+	    Sum->Hashes.FileSize(Size);
+	    Entries[Name] = Sum;
+         }
+         Entries[Name]->Hashes.push_back(hs);
+         FoundHashSum = true;
+	 if (FoundStrongHashSum == false && hs.usable() == true)
+	    FoundStrongHashSum = true;
+      }
+   }
+
+   bool AuthPossible = false;
+   if(FoundHashSum == false)
+      _error->Warning(_("No Hash entry in Release file %s"), Filename.c_str());
+   else if(FoundStrongHashSum == false)
+      _error->Warning(_("No Hash entry in Release file %s which is considered strong enough for security purposes"), Filename.c_str());
+   else
+      AuthPossible = true;
+
+   std::string const StrDate = Section.FindS("Date");
+   if (RFC1123StrToTime(StrDate, Date) == false)
+   {
+      _error->Warning( _("Invalid '%s' entry in Release file %s"), "Date", Filename.c_str());
+      Date = 0;
+   }
+
+   bool CheckDate = _config->FindB("Acquire::Check-Date", true);
+   if (d->CheckDate == metaIndex::TRI_NO)
+      CheckDate = false;
+   else if (d->CheckDate == metaIndex::TRI_YES)
+      CheckDate = true;
+
+   if (CheckDate)
+   {
+      auto const Label = GetLabel();
+      // get the user settings for this archive
+      time_t MaxFuture = d->DateMaxFuture;
+      if (MaxFuture == 0)
+      {
+	 MaxFuture = _config->FindI("Acquire::Max-FutureTime", 10);
+	 if (Label.empty() == false)
+	    MaxFuture = _config->FindI(("Acquire::Max-FutureTime::" + Label).c_str(), MaxFuture);
+      }
+
+      d->NotBefore = Date - MaxFuture;
+
+      bool CheckValidUntil = _config->FindB("Acquire::Check-Valid-Until", true);
+      if (d->CheckValidUntil == metaIndex::TRI_NO)
+	 CheckValidUntil = false;
+      else if (d->CheckValidUntil == metaIndex::TRI_YES)
+	 CheckValidUntil = true;
+
+      if (CheckValidUntil == true)
+      {
+	 std::string const StrValidUntil = Section.FindS("Valid-Until");
+
+	 // if we have a Valid-Until header in the Release file, use it as default
+	 if (StrValidUntil.empty() == false)
+	 {
+	    if (RFC1123StrToTime(StrValidUntil, ValidUntil) == false)
+	    {
+	       if (ErrorText != NULL)
+		  strprintf(*ErrorText, _("Invalid '%s' entry in Release file %s"), "Valid-Until", Filename.c_str());
+	       return false;
+	    }
+	 }
+	 auto const Label = GetLabel();
+	 // get the user settings for this archive and use what expires earlier
+	 time_t MaxAge = d->ValidUntilMax;
+	 if (MaxAge == 0)
+	 {
+	    MaxAge = _config->FindI("Acquire::Max-ValidTime", 0);
+	    if (Label.empty() == false)
+	       MaxAge = _config->FindI(("Acquire::Max-ValidTime::" + Label).c_str(), MaxAge);
+	 }
+	 time_t MinAge = d->ValidUntilMin;
+	 if (MinAge == 0)
+	 {
+	    MinAge = _config->FindI("Acquire::Min-ValidTime", 0);
+	    if (Label.empty() == false)
+	       MinAge = _config->FindI(("Acquire::Min-ValidTime::" + Label).c_str(), MinAge);
+	 }
+
+	 if (MinAge != 0 || ValidUntil != 0 || MaxAge != 0)
+	 {
+	    if (MinAge != 0 && ValidUntil != 0)
+	    {
+	       time_t const min_date = Date + MinAge;
+	       if (ValidUntil < min_date)
+		  ValidUntil = min_date;
+	    }
+	    if (MaxAge != 0 && Date != 0)
+	    {
+	       time_t const max_date = Date + MaxAge;
+	       if (ValidUntil == 0 || ValidUntil > max_date)
+		  ValidUntil = max_date;
+	    }
+	 }
+      }
+   }
+
+   /* as the Release file is parsed only after it was verified, the Signed-By field
+      does not effect the current, but the "next" Release file */
+   auto Sign = Section.FindS("Signed-By");
+   if (Sign.empty() == false)
+   {
+      SignedBy = NormalizeSignedBy(Sign, false);
+      if (SignedBy.empty() && ErrorText != NULL)
+	 strprintf(*ErrorText, _("Invalid '%s' entry in Release file %s"), "Signed-By", Filename.c_str());
+   }
+
+   if (AuthPossible)
+      LoadedSuccessfully = TRI_YES;
+   return AuthPossible;
+}
+									/*}}}*/
+time_t debReleaseIndex::GetNotBefore() const /*{{{*/
+{
+   return d->NotBefore;
+}
+									/*}}}*/
+metaIndex * debReleaseIndex::UnloadedClone() const			/*{{{*/
+{
+   if (Trusted == TRI_NO)
+      return new debReleaseIndex(URI, Dist, false, d->ReleaseOptions);
+   else if (Trusted == TRI_YES)
+      return new debReleaseIndex(URI, Dist, true, d->ReleaseOptions);
+   else
+      return new debReleaseIndex(URI, Dist, d->ReleaseOptions);
+}
+									/*}}}*/
+bool debReleaseIndex::parseSumData(const char *&Start, const char *End,	/*{{{*/
+				   std::string &Name, std::string &Hash, unsigned long long &Size)
+{
+   Name = "";
+   Hash = "";
+   Size = 0;
+   /* Skip over the first blank */
+   while ((*Start == '\t' || *Start == ' ' || *Start == '\n' || *Start == '\r')
+	  && Start < End)
+      Start++;
+   if (Start >= End)
+      return false;
+
+   /* Move EntryEnd to the end of the first entry (the hash) */
+   const char *EntryEnd = Start;
+   while ((*EntryEnd != '\t' && *EntryEnd != ' ')
+	  && EntryEnd < End)
+      EntryEnd++;
+   if (EntryEnd == End)
+      return false;
+
+   Hash.append(Start, EntryEnd-Start);
+
+   /* Skip over intermediate blanks */
+   Start = EntryEnd;
+   while (*Start == '\t' || *Start == ' ')
+      Start++;
+   if (Start >= End)
+      return false;
+   
+   EntryEnd = Start;
+   /* Find the end of the second entry (the size) */
+   while ((*EntryEnd != '\t' && *EntryEnd != ' ' )
+	  && EntryEnd < End)
+      EntryEnd++;
+   if (EntryEnd == End)
+      return false;
+   
+   Size = strtoull (Start, NULL, 10);
+      
+   /* Skip over intermediate blanks */
+   Start = EntryEnd;
+   while (*Start == '\t' || *Start == ' ')
+      Start++;
+   if (Start >= End)
+      return false;
+   
+   EntryEnd = Start;
+   /* Find the end of the third entry (the filename) */
+   while ((*EntryEnd != '\t' && *EntryEnd != ' ' && 
+           *EntryEnd != '\n' && *EntryEnd != '\r')
+	  && EntryEnd < End)
+      EntryEnd++;
+
+   Name.append(Start, EntryEnd-Start);
+   Start = EntryEnd; //prepare for the next round
+   return true;
+}
+									/*}}}*/
+
+bool debReleaseIndex::GetIndexes(pkgAcquire *Owner, bool const &GetAll)/*{{{*/
+{
+#define APT_TARGET(X) IndexTarget("", X, MetaIndexInfo(X), MetaIndexURI(X), false, false, d->ReleaseOptions)
+   pkgAcqMetaClearSig * const TransactionManager = new pkgAcqMetaClearSig(Owner,
+	 APT_TARGET("InRelease"), APT_TARGET("Release"), APT_TARGET("Release.gpg"), this);
+#undef APT_TARGET
+   // special case for --print-uris
+   if (GetAll)
+      for (auto const &Target: GetIndexTargets())
+	 if (Target.Option(IndexTarget::FALLBACK_OF).empty())
+	    new pkgAcqIndex(Owner, TransactionManager, Target);
+
+   return true;
+}
+									/*}}}*/
+// ReleaseIndex::Set* TriState options					/*{{{*/
+bool debReleaseIndex::SetTrusted(TriState const pTrusted)
+{
+   if (Trusted == TRI_UNSET)
+      Trusted = pTrusted;
+   else if (Trusted != pTrusted)
+      // TRANSLATOR: The first is an option name from sources.list manpage, the other two URI and Suite
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Trusted", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetCheckValidUntil(TriState const pCheckValidUntil)
+{
+   if (d->CheckValidUntil == TRI_UNSET)
+      d->CheckValidUntil = pCheckValidUntil;
+   else if (d->CheckValidUntil != pCheckValidUntil)
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Check-Valid-Until", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetValidUntilMin(time_t const Valid)
+{
+   if (d->ValidUntilMin == 0)
+      d->ValidUntilMin = Valid;
+   else if (d->ValidUntilMin != Valid)
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Min-ValidTime", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetValidUntilMax(time_t const Valid)
+{
+   if (d->ValidUntilMax == 0)
+      d->ValidUntilMax = Valid;
+   else if (d->ValidUntilMax != Valid)
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Max-ValidTime", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetCheckDate(TriState const pCheckDate)
+{
+   if (d->CheckDate == TRI_UNSET)
+      d->CheckDate = pCheckDate;
+   else if (d->CheckDate != pCheckDate)
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Check-Date", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetDateMaxFuture(time_t const DateMaxFuture)
+{
+   if (d->DateMaxFuture == 0)
+      d->DateMaxFuture = DateMaxFuture;
+   else if (d->DateMaxFuture != DateMaxFuture)
+      return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), "Date-Max-Future", URI.c_str(), Dist.c_str());
+   return true;
+}
+bool debReleaseIndex::SetSignedBy(std::string const &pSignedBy)
+{
+   if (SignedBy.empty() == true && pSignedBy.empty() == false)
+   {
+      SignedBy = NormalizeSignedBy(pSignedBy, true);
+      if (SignedBy.empty())
+	 _error->Error(_("Invalid value set for option %s regarding source %s %s (%s)"), "Signed-By", URI.c_str(), Dist.c_str(), "not a fingerprint");
+   }
+   else
+   {
+      auto const normalSignedBy = NormalizeSignedBy(pSignedBy, true);
+      if (normalSignedBy != SignedBy)
+	 return _error->Error(_("Conflicting values set for option %s regarding source %s %s: %s != %s"), "Signed-By", URI.c_str(), Dist.c_str(), SignedBy.c_str(), normalSignedBy.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// ReleaseIndex::IsTrusted						/*{{{*/
+bool debReleaseIndex::IsTrusted() const
+{
+   if (Trusted == TRI_YES)
+      return true;
+   else if (Trusted == TRI_NO)
+      return false;
+
+
+   if(_config->FindB("APT::Authentication::TrustCDROM", false))
+      if(URI.substr(0,strlen("cdrom:")) == "cdrom:")
+	 return true;
+
+   if (FileExists(MetaIndexFile("Release.gpg")))
+      return true;
+
+   return FileExists(MetaIndexFile("InRelease"));
+}
+									/*}}}*/
+bool debReleaseIndex::IsArchitectureSupported(std::string const &arch) const/*{{{*/
+{
+   if (d->Architectures.empty())
+      return true;
+   return std::find(d->Architectures.begin(), d->Architectures.end(), arch) != d->Architectures.end();
+}
+									/*}}}*/
+bool debReleaseIndex::IsArchitectureAllSupportedFor(IndexTarget const &target) const/*{{{*/
+{
+   if (target.Options.find("Force-Support-For-All") != target.Options.end())
+      return true;
+   if (IsArchitectureSupported("all") == false)
+      return false;
+   if (d->NoSupportForAll.empty())
+      return true;
+   return std::find(d->NoSupportForAll.begin(), d->NoSupportForAll.end(), target.Option(IndexTarget::CREATED_BY)) == d->NoSupportForAll.end();
+}
+									/*}}}*/
+bool debReleaseIndex::HasSupportForComponent(std::string const &component) const/*{{{*/
+{
+   if (d->SupportedComponents.empty())
+      return true;
+   return std::find(d->SupportedComponents.begin(), d->SupportedComponents.end(), component) != d->SupportedComponents.end();
+}
+									/*}}}*/
+std::vector <pkgIndexFile *> *debReleaseIndex::GetIndexFiles()		/*{{{*/
+{
+   if (Indexes != NULL)
+      return Indexes;
+
+   Indexes = new std::vector<pkgIndexFile*>();
+   bool const istrusted = IsTrusted();
+   for (auto const &T: GetIndexTargets())
+   {
+      std::string const TargetName = T.Option(IndexTarget::CREATED_BY);
+      if (TargetName == "Packages")
+	 Indexes->push_back(new debPackagesIndex(T, istrusted));
+      else if (TargetName == "Sources")
+	 Indexes->push_back(new debSourcesIndex(T, istrusted));
+      else if (TargetName == "Translations")
+	 Indexes->push_back(new debTranslationsIndex(T));
+   }
+   return Indexes;
+}
+									/*}}}*/
+std::map<std::string, std::string> debReleaseIndex::GetReleaseOptions()
+{
+   return d->ReleaseOptions;
+}
+
+static bool ReleaseFileName(debReleaseIndex const * const That, std::string &ReleaseFile)/*{{{*/
+{
+   ReleaseFile = That->MetaIndexFile("InRelease");
+   bool releaseExists = false;
+   if (FileExists(ReleaseFile) == true)
+      releaseExists = true;
+   else
+   {
+      ReleaseFile = That->MetaIndexFile("Release");
+      if (FileExists(ReleaseFile))
+	 releaseExists = true;
+   }
+   return releaseExists;
+}
+									/*}}}*/
+bool debReleaseIndex::Merge(pkgCacheGenerator &Gen,OpProgress * /*Prog*/) const/*{{{*/
+{
+   std::string ReleaseFile;
+   bool const releaseExists = ReleaseFileName(this, ReleaseFile);
+
+   ::URI Tmp(URI);
+   if (Gen.SelectReleaseFile(ReleaseFile, Tmp.Host) == false)
+      return _error->Error("Problem with SelectReleaseFile %s", ReleaseFile.c_str());
+
+   if (releaseExists == false)
+      return true;
+
+   FileFd Rel;
+   // Beware: The 'Release' file might be clearsigned in case the
+   // signature for an 'InRelease' file couldn't be checked
+   if (OpenMaybeClearSignedFile(ReleaseFile, Rel) == false)
+      return false;
+
+   // Store the IMS information
+   pkgCache::RlsFileIterator File = Gen.GetCurRlsFile();
+   pkgCacheGenerator::Dynamic<pkgCache::RlsFileIterator> DynFile(File);
+   // Rel can't be used as this is potentially a temporary file
+   struct stat Buf;
+   if (stat(ReleaseFile.c_str(), &Buf) != 0)
+      return _error->Errno("fstat", "Unable to stat file %s", ReleaseFile.c_str());
+   File->Size = Buf.st_size;
+   File->mtime = Buf.st_mtime;
+
+   pkgTagFile TagFile(&Rel, Rel.Size());
+   pkgTagSection Section;
+   if (Rel.IsOpen() == false || Rel.Failed() || TagFile.Step(Section) == false)
+      return false;
+
+   std::string data;
+   #define APT_INRELEASE(TYPE, TAG, STORE) \
+   data = Section.FindS(TAG); \
+   if (data.empty() == false) \
+   { \
+      map_stringitem_t const storage = Gen.StoreString(pkgCacheGenerator::TYPE, data); \
+      if (storage == 0) return false; \
+      STORE = storage; \
+   }
+   APT_INRELEASE(MIXED, "Suite", File->Archive)
+   APT_INRELEASE(VERSIONNUMBER, "Version", File->Version)
+   APT_INRELEASE(MIXED, "Origin", File->Origin)
+   APT_INRELEASE(MIXED, "Codename", File->Codename)
+   APT_INRELEASE(MIXED, "Label", File->Label)
+   #undef APT_INRELEASE
+   Section.FindFlag("NotAutomatic", File->Flags, pkgCache::Flag::NotAutomatic);
+   Section.FindFlag("ButAutomaticUpgrades", File->Flags, pkgCache::Flag::ButAutomaticUpgrades);
+
+   return true;
+}
+									/*}}}*/
+// ReleaseIndex::FindInCache - Find this index				/*{{{*/
+pkgCache::RlsFileIterator debReleaseIndex::FindInCache(pkgCache &Cache, bool const ModifyCheck) const
+{
+   std::string ReleaseFile;
+   bool const releaseExists = ReleaseFileName(this, ReleaseFile);
+
+   pkgCache::RlsFileIterator File = Cache.RlsFileBegin();
+   for (; File.end() == false; ++File)
+   {
+       if (File->FileName == 0 || ReleaseFile != File.FileName())
+	 continue;
+
+       // empty means the file does not exist by "design"
+       if (ModifyCheck == false || (releaseExists == false && File->Size == 0))
+	  return File;
+
+      struct stat St;
+      if (stat(File.FileName(),&St) != 0)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "ReleaseIndex::FindInCache - stat failed on " << File.FileName() << std::endl;
+	 return pkgCache::RlsFileIterator(Cache);
+      }
+      if ((unsigned)St.st_size != File->Size || St.st_mtime != File->mtime)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "ReleaseIndex::FindInCache - size (" << St.st_size << " <> " << File->Size
+			<< ") or mtime (" << St.st_mtime << " <> " << File->mtime
+			<< ") doesn't match for " << File.FileName() << std::endl;
+	 return pkgCache::RlsFileIterator(Cache);
+      }
+      return File;
+   }
+
+   return File;
+}
+									/*}}}*/
+
+class APT_HIDDEN debSLTypeDebian : public pkgSourceList::Type		/*{{{*/
+{
+   static std::optional<std::vector<std::string>> getDefaultSetOf(std::string const &Name,
+	 std::map<std::string, std::string> const &Options)
+   {
+      auto const val = Options.find(Name);
+      if (val != Options.end())
+	 return VectorizeString(val->second, ',');
+      return {};
+   }
+   static std::vector<std::string> applyPlusMinusOptions(std::string const &Name,
+	 std::map<std::string, std::string> const &Options, std::vector<std::string> &&Values)
+   {
+      auto val = Options.find(Name + "+");
+      if (val != Options.end())
+      {
+	 std::vector<std::string> const plus = VectorizeString(val->second, ',');
+	 std::copy_if(plus.begin(), plus.end(), std::back_inserter(Values), [&Values](std::string const &v) {
+	       return std::find(Values.begin(), Values.end(), v) == Values.end();
+	       });
+      }
+      if ((val = Options.find(Name + "-")) != Options.end())
+      {
+	 std::vector<std::string> const minus = VectorizeString(val->second, ',');
+	 Values.erase(std::remove_if(Values.begin(), Values.end(), [&minus](std::string const &v) {
+		  return std::find(minus.begin(), minus.end(), v) != minus.end();
+		  }), Values.end());
+      }
+      return std::move(Values);
+   }
+   static std::vector<std::string> parsePlusMinusOptions(std::string const &Name,
+	 std::map<std::string, std::string> const &Options, std::vector<std::string> const &defaultValues)
+   {
+      return applyPlusMinusOptions(Name, Options, getDefaultSetOf(Name, Options).value_or(defaultValues));
+   }
+   static std::vector<std::string> parsePlusMinusArchOptions(std::string const &Name,
+	 std::map<std::string, std::string> const &Options)
+   {
+      std::vector<std::string> Values;
+     if (auto opt = getDefaultSetOf(Name, Options); opt.has_value())
+        Values = opt.value();
+     else
+     {
+	Values = APT::Configuration::getArchitectures();
+	auto veryforeign = _config->FindVector("APT::BarbarianArchitectures");
+	Values.reserve(Values.size() + veryforeign.size());
+	std::move(veryforeign.begin(), veryforeign.end(), std::back_inserter(Values));
+     }
+      // all is a very special architecture users shouldn't be concerned with explicitly
+      // but if the user does, do not override the choice
+      auto const val = Options.find(Name + "-");
+      if (val != Options.end())
+      {
+	 std::vector<std::string> const minus = VectorizeString(val->second, ',');
+	 if (std::find(minus.begin(), minus.end(), "all") != minus.end())
+	    return applyPlusMinusOptions(Name, Options, std::move(Values));
+      }
+      Values = applyPlusMinusOptions(Name, Options, std::move(Values));
+      if (std::find(Values.begin(), Values.end(), "all") == Values.end())
+	 Values.push_back("implicit:all");
+      return Values;
+   }
+   static std::vector<std::string> parsePlusMinusTargetOptions(char const * const Name,
+	 std::map<std::string, std::string> const &Options)
+   {
+      std::vector<std::string> const alltargets = _config->FindVector(std::string("Acquire::IndexTargets::") + Name, "", true);
+      std::vector<std::string> deftargets;
+      deftargets.reserve(alltargets.size());
+      std::copy_if(alltargets.begin(), alltargets.end(), std::back_inserter(deftargets), [&](std::string const &t) {
+	 std::string c = "Acquire::IndexTargets::";
+	 c.append(Name).append("::").append(t).append("::DefaultEnabled");
+	 return _config->FindB(c, true);
+      });
+      std::vector<std::string> mytargets = parsePlusMinusOptions("target", Options, deftargets);
+      for (auto const &target : alltargets)
+      {
+	 std::map<std::string, std::string>::const_iterator const opt = Options.find(target);
+	 if (opt == Options.end())
+	    continue;
+	 auto const idMatch = [&](std::string const &t) {
+	    return target == _config->Find(std::string("Acquire::IndexTargets::") + Name + "::" + t + "::Identifier", t);
+	 };
+	 if (StringToBool(opt->second))
+	    std::copy_if(alltargets.begin(), alltargets.end(), std::back_inserter(mytargets), idMatch);
+	 else
+	    mytargets.erase(std::remove_if(mytargets.begin(), mytargets.end(), idMatch), mytargets.end());
+      }
+      // if we can't order it in a 1000 steps we give up… probably a cycle
+      for (auto i = 0; i < 1000; ++i)
+      {
+	 bool Changed = false;
+	 for (auto t = mytargets.begin(); t != mytargets.end(); ++t)
+	 {
+	    std::string const fallback = _config->Find(std::string("Acquire::IndexTargets::") + Name + "::" + *t + "::Fallback-Of");
+	    if (fallback.empty())
+	       continue;
+	    auto const faller = std::find(mytargets.begin(), mytargets.end(), fallback);
+	    if (faller == mytargets.end() || faller < t)
+	       continue;
+	    Changed = true;
+	    auto const tv = *t;
+	    mytargets.erase(t);
+	    mytargets.emplace_back(tv);
+	    break;
+	 }
+	 if (Changed == false)
+	    break;
+      }
+      // remove duplicates without changing the order (in first appearance)
+      {
+	 std::set<std::string> seenOnce;
+	 mytargets.erase(std::remove_if(mytargets.begin(), mytargets.end(), [&](std::string const &t) {
+	    return seenOnce.insert(t).second == false;
+	 }), mytargets.end());
+      }
+      return mytargets;
+   }
+
+   metaIndex::TriState GetTriStateOption(std::map<std::string, std::string>const &Options, char const * const name) const
+   {
+      std::map<std::string, std::string>::const_iterator const opt = Options.find(name);
+      if (opt != Options.end())
+	 return StringToBool(opt->second, false) ? metaIndex::TRI_YES : metaIndex::TRI_NO;
+      return metaIndex::TRI_DONTCARE;
+   }
+
+   static time_t GetTimeOption(std::map<std::string, std::string>const &Options, char const * const name)
+   {
+      std::map<std::string, std::string>::const_iterator const opt = Options.find(name);
+      if (opt == Options.end())
+	 return 0;
+      return strtoull(opt->second.c_str(), NULL, 10);
+   }
+
+   static bool GetBoolOption(std::map<std::string, std::string> const &Options, char const * const name, bool const defVal)
+   {
+      std::map<std::string, std::string>::const_iterator const opt = Options.find(name);
+      if (opt == Options.end())
+	 return defVal;
+      return StringToBool(opt->second, defVal);
+   }
+
+   static std::vector<std::string> GetMapKeys(std::map<std::string, std::string> const &Options)
+   {
+      std::vector<std::string> ret;
+      ret.reserve(Options.size());
+      std::transform(Options.begin(), Options.end(), std::back_inserter(ret),
+		     [](auto &&O) { return O.first; });
+      std::sort(ret.begin(), ret.end());
+      return ret;
+   }
+
+   static bool MapsAreEqual(std::map<std::string, std::string> const &OptionsA,
+	 std::map<std::string, std::string> const &OptionsB,
+	 std::string const &URI, std::string const &Dist)
+   {
+      auto const KeysA = GetMapKeys(OptionsA);
+      auto const KeysB = GetMapKeys(OptionsB);
+      auto const m = std::mismatch(KeysA.begin(), KeysA.end(), KeysB.begin());
+      if (m.first != KeysA.end())
+      {
+	 if (std::find(KeysB.begin(), KeysB.end(), *m.first) == KeysB.end())
+	    return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), m.first->c_str(), "<set>", "<unset>");
+	 else
+	    return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), m.second->c_str(), "<set>", "<unset>");
+      }
+      if (m.second != KeysB.end())
+      {
+	 if (std::find(KeysA.begin(), KeysA.end(), *m.second) == KeysA.end())
+	    return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), m.first->c_str(), "<set>", "<unset>");
+	 else
+	    return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), m.second->c_str(), "<set>", "<unset>");
+      }
+      for (auto&& key: KeysA)
+      {
+	 if (key == "BASE_URI" || key == "REPO_URI" || key == "SITE" || key == "RELEASE")
+	    continue;
+	 auto const a = OptionsA.find(key);
+	 auto const b = OptionsB.find(key);
+	 if (unlikely(a == OptionsA.end() || b == OptionsB.end()) || a->second != b->second)
+	    return _error->Error(_("Conflicting values set for option %s regarding source %s %s"), key.c_str(), URI.c_str(), Dist.c_str());
+      }
+      return true;
+   }
+
+   static debReleaseIndex * GetDebReleaseIndexBy(std::vector<metaIndex *> &List, std::string const &URI,
+			   std::string const &Dist, std::map<std::string, std::string> const &Options)
+   {
+      std::map<std::string, std::string> ReleaseOptions{{
+	 {"BASE_URI", constructMetaIndexURI(URI, Dist, "")},
+	 {"REPO_URI", URI},
+	 {"SITE", ::URI::ArchiveOnly(URI)},
+	 {"RELEASE", (Dist == "/") ? "" : Dist},
+      }};
+      if (GetBoolOption(Options, "allow-insecure", _config->FindB("Acquire::AllowInsecureRepositories")))
+	 ReleaseOptions.emplace("ALLOW_INSECURE", "true");
+      if (GetBoolOption(Options, "allow-weak", _config->FindB("Acquire::AllowWeakRepositories")))
+	 ReleaseOptions.emplace("ALLOW_WEAK", "true");
+      if (GetBoolOption(Options, "allow-downgrade-to-insecure", _config->FindB("Acquire::AllowDowngradeToInsecureRepositories")))
+	 ReleaseOptions.emplace("ALLOW_DOWNGRADE_TO_INSECURE", "true");
+
+      auto InReleasePath = Options.find("inrelease-path");
+      if (InReleasePath != Options.end())
+	 ReleaseOptions.emplace("INRELEASE_PATH", InReleasePath->second);
+
+      debReleaseIndex * Deb = nullptr;
+      std::string const FileName = URItoFileName(constructMetaIndexURI(URI, Dist, "Release"));
+      for (auto const &I: List)
+      {
+	 // We only worry about debian entries here
+	 if (strcmp(I->GetType(), "deb") != 0)
+	    continue;
+
+	 auto const D = dynamic_cast<debReleaseIndex*>(I);
+	 if (unlikely(D == nullptr))
+	    continue;
+
+	 /* This check ensures that there will be only one Release file
+	    queued for all the Packages files and Sources files it
+	    corresponds to. */
+	 if (URItoFileName(D->MetaIndexURI("Release")) == FileName)
+	 {
+	    if (MapsAreEqual(ReleaseOptions, D->GetReleaseOptions(), URI, Dist) == false)
+	       return nullptr;
+	    Deb = D;
+	    break;
+	 }
+      }
+
+      // No currently created Release file indexes this entry, so we create a new one.
+      if (Deb == nullptr)
+      {
+	 Deb = new debReleaseIndex(URI, Dist, ReleaseOptions);
+	 List.push_back(Deb);
+      }
+      return Deb;
+   }
+
+   protected:
+
+   bool CreateItemInternal(std::vector<metaIndex *> &List, std::string const &URI,
+			   std::string const &Dist, std::string const &Section,
+			   bool const &IsSrc, std::map<std::string, std::string> const &Options) const
+   {
+      auto const Deb = GetDebReleaseIndexBy(List, URI, Dist, Options);
+      if (Deb == nullptr)
+	 return false;
+
+      bool const UsePDiffs = GetBoolOption(Options, "pdiffs", _config->FindB("Acquire::PDiffs", true));
+
+      std::string UseByHash = _config->Find("APT::Acquire::By-Hash", "yes");
+      UseByHash = _config->Find("Acquire::By-Hash", UseByHash);
+      {
+	 std::string const host = ::URI(URI).Host;
+	 if (host.empty() == false)
+	 {
+	    UseByHash = _config->Find("APT::Acquire::" + host + "::By-Hash", UseByHash);
+	    UseByHash = _config->Find("Acquire::" + host + "::By-Hash", UseByHash);
+	 }
+	 std::map<std::string, std::string>::const_iterator const opt = Options.find("by-hash");
+	 if (opt != Options.end())
+	    UseByHash = opt->second;
+      }
+
+      auto const entry = Options.find("sourceslist-entry");
+      Deb->AddComponent(
+	    entry->second,
+	    IsSrc,
+	    Section,
+	    parsePlusMinusTargetOptions(Name, Options),
+	    parsePlusMinusArchOptions("arch", Options),
+	    parsePlusMinusOptions("lang", Options, APT::Configuration::getLanguages(true)),
+	    UsePDiffs,
+	    UseByHash
+	    );
+
+      if (Deb->SetTrusted(GetTriStateOption(Options, "trusted")) == false ||
+	  Deb->SetCheckValidUntil(GetTriStateOption(Options, "check-valid-until")) == false ||
+	  Deb->SetValidUntilMax(GetTimeOption(Options, "valid-until-max")) == false ||
+	  Deb->SetValidUntilMin(GetTimeOption(Options, "valid-until-min")) == false ||
+	  Deb->SetCheckDate(GetTriStateOption(Options, "check-date")) == false ||
+	  Deb->SetDateMaxFuture(GetTimeOption(Options, "date-max-future")) == false)
+	 return false;
+
+      std::map<std::string, std::string>::const_iterator const signedby = Options.find("signed-by");
+      if (signedby == Options.end())
+      {
+	 bool alreadySet = false;
+	 std::string filename;
+	 if (ReleaseFileName(Deb, filename))
+	 {
+	    auto OldDeb = Deb->UnloadedClone();
+	    _error->PushToStack();
+	    OldDeb->Load(filename, nullptr);
+	    bool const goodLoad = _error->PendingError() == false;
+	    _error->RevertToStack();
+	    if (goodLoad)
+	    {
+	       if (OldDeb->GetValidUntil() > 0)
+	       {
+		  time_t const invalid_since = time(NULL) - OldDeb->GetValidUntil();
+		  if (invalid_since <= 0)
+		  {
+		     Deb->SetSignedBy(OldDeb->GetSignedBy());
+		     alreadySet = true;
+		  }
+	       }
+	    }
+	    delete OldDeb;
+	 }
+	 if (alreadySet == false && Deb->SetSignedBy("") == false)
+	    return false;
+      }
+      else
+      {
+	 if (Deb->SetSignedBy(signedby->second) == false)
+	    return false;
+      }
+
+      return true;
+   }
+
+   debSLTypeDebian(char const * const Name, char const * const Label) : Type(Name, Label)
+   {
+   }
+};
+									/*}}}*/
+class APT_HIDDEN debSLTypeDeb : public debSLTypeDebian			/*{{{*/
+{
+   public:
+
+   bool CreateItem(std::vector<metaIndex *> &List, std::string const &URI,
+		   std::string const &Dist, std::string const &Section,
+		   std::map<std::string, std::string> const &Options) const APT_OVERRIDE
+   {
+      return CreateItemInternal(List, URI, Dist, Section, false, Options);
+   }
+
+   debSLTypeDeb() : debSLTypeDebian("deb", "Debian binary tree")
+   {
+   }
+};
+									/*}}}*/
+class APT_HIDDEN debSLTypeDebSrc : public debSLTypeDebian		/*{{{*/
+{
+   public:
+
+   bool CreateItem(std::vector<metaIndex *> &List, std::string const &URI,
+		   std::string const &Dist, std::string const &Section,
+		   std::map<std::string, std::string> const &Options) const APT_OVERRIDE
+   {
+      return CreateItemInternal(List, URI, Dist, Section, true, Options);
+   }
+
+   debSLTypeDebSrc() : debSLTypeDebian("deb-src", "Debian source tree")
+   {
+   }
+};
+									/*}}}*/
+
+APT_HIDDEN debSLTypeDeb _apt_DebType;
+APT_HIDDEN debSLTypeDebSrc _apt_DebSrcType;
diff --git a/apt-pkg/deb/debmetaindex.h b/apt-pkg/deb/debmetaindex.h
new file mode 100644
index 0000000..717f08e
--- /dev/null
+++ b/apt-pkg/deb/debmetaindex.h
@@ -0,0 +1,72 @@
+#ifndef PKGLIB_DEBMETAINDEX_H
+#define PKGLIB_DEBMETAINDEX_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/metaindex.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+
+class pkgAcquire;
+class pkgIndexFile;
+class IndexTarget;
+class pkgCacheGenerator;
+class OpProgress;
+class debReleaseIndexPrivate;
+
+class APT_HIDDEN debReleaseIndex : public metaIndex
+{
+   debReleaseIndexPrivate * const d;
+
+   APT_HIDDEN bool parseSumData(const char *&Start, const char *End, std::string &Name,
+		     std::string &Hash, unsigned long long &Size);
+   public:
+
+   APT_HIDDEN std::string MetaIndexInfo(const char *Type) const;
+   APT_HIDDEN std::string MetaIndexFile(const char *Types) const;
+   APT_HIDDEN std::string MetaIndexURI(const char *Type) const;
+
+   debReleaseIndex(std::string const &URI, std::string const &Dist, std::map<std::string,std::string> const &Options);
+   debReleaseIndex(std::string const &URI, std::string const &Dist, bool const Trusted, std::map<std::string,std::string> const &Options);
+   virtual ~debReleaseIndex();
+
+   virtual std::string ArchiveURI(std::string const &File) const APT_OVERRIDE;
+   virtual bool GetIndexes(pkgAcquire *Owner, bool const &GetAll=false) APT_OVERRIDE;
+   virtual std::vector<IndexTarget> GetIndexTargets() const APT_OVERRIDE;
+
+   virtual std::string Describe() const APT_OVERRIDE;
+   virtual pkgCache::RlsFileIterator FindInCache(pkgCache &Cache, bool const ModifyCheck) const APT_OVERRIDE;
+   virtual bool Merge(pkgCacheGenerator &Gen,OpProgress *Prog) const APT_OVERRIDE;
+
+   virtual bool Load(std::string const &Filename, std::string * const ErrorText) APT_OVERRIDE;
+   virtual metaIndex * UnloadedClone() const APT_OVERRIDE;
+
+   virtual std::vector <pkgIndexFile *> *GetIndexFiles() APT_OVERRIDE;
+
+   bool SetTrusted(TriState const Trusted);
+   bool SetCheckValidUntil(TriState const Trusted);
+   bool SetValidUntilMin(time_t const Valid);
+   bool SetValidUntilMax(time_t const Valid);
+   bool SetCheckDate(TriState const CheckDate);
+   bool SetDateMaxFuture(time_t const DateMaxFuture);
+   bool SetSignedBy(std::string const &SignedBy);
+   std::map<std::string, std::string> GetReleaseOptions();
+
+   virtual bool IsTrusted() const APT_OVERRIDE;
+   bool IsArchitectureSupported(std::string const &arch) const override;
+   bool IsArchitectureAllSupportedFor(IndexTarget const &target) const override;
+   bool HasSupportForComponent(std::string const &component) const override;
+
+   APT_PURE time_t GetNotBefore() const override;
+
+   void AddComponent(std::string const &sourcesEntry,
+	 bool const isSrc, std::string const &Name,
+	 std::vector<std::string> const &Targets,
+	 std::vector<std::string> const &Architectures,
+	 std::vector<std::string> Languages,
+	 bool const usePDiffs, std::string const &useByHash);
+};
+
+#endif
diff --git a/apt-pkg/deb/debrecords.cc b/apt-pkg/deb/debrecords.cc
new file mode 100644
index 0000000..e2ffaef
--- /dev/null
+++ b/apt-pkg/deb/debrecords.cc
@@ -0,0 +1,228 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Debian Package Records - Parser for debian package records
+     
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/debindexfile.h>
+#include <apt-pkg/debrecords.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <langinfo.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+// RecordParser::debRecordParser - Constructor				/*{{{*/
+debRecordParser::debRecordParser(string FileName,pkgCache &Cache) :
+   debRecordParserBase(), d(NULL), File(FileName, FileFd::ReadOnly, FileFd::Extension),
+   Tags(&File, std::max(Cache.Head().MaxVerFileSize, Cache.Head().MaxDescFileSize) + 200)
+{
+}
+									/*}}}*/
+// RecordParser::Jump - Jump to a specific record			/*{{{*/
+bool debRecordParser::Jump(pkgCache::VerFileIterator const &Ver)
+{
+   if (Ver.end() == true)
+      return false;
+   return Tags.Jump(Section,Ver->Offset);
+}
+bool debRecordParser::Jump(pkgCache::DescFileIterator const &Desc)
+{
+   if (Desc.end() == true)
+      return false;
+   return Tags.Jump(Section,Desc->Offset);
+}
+									/*}}}*/
+debRecordParser::~debRecordParser() {}
+
+debRecordParserBase::debRecordParserBase() : Parser(), d(NULL) {}
+// RecordParserBase::FileName - Return the archive filename on the site	/*{{{*/
+string debRecordParserBase::FileName()
+{
+   return Section.Find(pkgTagSection::Key::Filename).to_string();
+}
+									/*}}}*/
+// RecordParserBase::Name - Return the package name			/*{{{*/
+string debRecordParserBase::Name()
+{
+   auto Result = Section.Find(pkgTagSection::Key::Package).to_string();
+
+   // Normalize mixed case package names to lower case, like dpkg does
+   // See Bug#807012 for details
+   std::transform(Result.begin(), Result.end(), Result.begin(), tolower_ascii);
+
+   return Result;
+}
+									/*}}}*/
+// RecordParserBase::Homepage - Return the package homepage		/*{{{*/
+string debRecordParserBase::Homepage()
+{
+   return Section.Find(pkgTagSection::Key::Homepage).to_string();
+}
+									/*}}}*/
+// RecordParserBase::Hashes - return the available archive hashes	/*{{{*/
+HashStringList debRecordParserBase::Hashes() const
+{
+   HashStringList hashes;
+   for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+   {
+      std::string const hash = Section.FindS(*type);
+      if (hash.empty() == false)
+	 hashes.push_back(HashString(*type, hash));
+   }
+   auto const size = Section.FindULL(pkgTagSection::Key::Size, 0);
+   if (size != 0)
+      hashes.FileSize(size);
+   return hashes;
+}
+									/*}}}*/
+// RecordParserBase::Maintainer - Return the maintainer email		/*{{{*/
+string debRecordParserBase::Maintainer()
+{
+   return Section.Find(pkgTagSection::Key::Maintainer).to_string();
+}
+									/*}}}*/
+// RecordParserBase::RecordField - Return the value of an arbitrary field	/*{{*/
+string debRecordParserBase::RecordField(const char *fieldName)
+{
+   return Section.FindS(fieldName);
+}
+									/*}}}*/
+// RecordParserBase::ShortDesc - Return a 1 line description		/*{{{*/
+string debRecordParserBase::ShortDesc(std::string const &lang)
+{
+   string const Res = LongDesc(lang);
+   if (Res.empty() == true)
+      return "";
+   string::size_type const Pos = Res.find('\n');
+   if (Pos == string::npos)
+      return Res;
+   return string(Res,0,Pos);
+}
+									/*}}}*/
+// RecordParserBase::LongDesc - Return a longer description		/*{{{*/
+string debRecordParserBase::LongDesc(std::string const &lang)
+{
+   string orig;
+   if (lang.empty() == true)
+   {
+      std::vector<string> const lang = APT::Configuration::getLanguages();
+      for (std::vector<string>::const_iterator l = lang.begin();
+	    l != lang.end(); ++l)
+      {
+	 std::string const tagname = "Description-" + *l;
+	 orig = Section.FindS(tagname);
+	 if (orig.empty() == false)
+	    break;
+	 else if (*l == "en")
+	 {
+	    orig = Section.Find(pkgTagSection::Key::Description).to_string();
+	    if (orig.empty() == false)
+	       break;
+	 }
+      }
+      if (orig.empty() == true)
+	 orig = Section.Find(pkgTagSection::Key::Description).to_string();
+   }
+   else
+   {
+      std::string const tagname = "Description-" + lang;
+      orig = Section.FindS(tagname.c_str());
+      if (orig.empty() == true && lang == "en")
+	 orig = Section.Find(pkgTagSection::Key::Description).to_string();
+   }
+
+   char const * const codeset = nl_langinfo(CODESET);
+   if (strcmp(codeset,"UTF-8") != 0) {
+      string dest;
+      UTF8ToCodeset(codeset, orig, &dest);
+      return dest;
+   }
+
+   return orig;
+}
+									/*}}}*/
+
+static const char * const SourceVerSeparators = " ()";
+// RecordParserBase::SourcePkg - Return the source package name if any	/*{{{*/
+string debRecordParserBase::SourcePkg()
+{
+   auto Res = Section.Find(pkgTagSection::Key::Source).to_string();
+   auto const Pos = Res.find_first_of(SourceVerSeparators);
+   if (Pos != std::string::npos)
+      Res.erase(Pos);
+   return Res;
+}
+									/*}}}*/
+// RecordParserBase::SourceVer - Return the source version number if present	/*{{{*/
+string debRecordParserBase::SourceVer()
+{
+   auto const Pkg = Section.Find(pkgTagSection::Key::Source).to_string();
+   string::size_type Pos = Pkg.find_first_of(SourceVerSeparators);
+   if (Pos == string::npos)
+      return "";
+
+   string::size_type VerStart = Pkg.find_first_not_of(SourceVerSeparators, Pos);
+   if(VerStart == string::npos)
+     return "";
+
+   string::size_type VerEnd = Pkg.find_first_of(SourceVerSeparators, VerStart);
+   if(VerEnd == string::npos)
+     // Corresponds to the case of, e.g., "foo (1.2" without a closing
+     // paren.  Be liberal and guess what it means.
+     return string(Pkg, VerStart);
+   else
+     return string(Pkg, VerStart, VerEnd - VerStart);
+}
+									/*}}}*/
+// RecordParserBase::GetRec - Return the whole record			/*{{{*/
+void debRecordParserBase::GetRec(const char *&Start,const char *&Stop)
+{
+   Section.GetSection(Start,Stop);
+}
+									/*}}}*/
+debRecordParserBase::~debRecordParserBase() {}
+
+bool debDebFileRecordParser::LoadContent()
+{
+   // load content only once
+   if (controlContent.empty() == false)
+      return true;
+
+   std::ostringstream content;
+   if (debDebPkgFileIndex::GetContent(content, debFileName) == false)
+      return false;
+   // add two newlines to make sure the scanner finds the section,
+   // which is usually done by pkgTagFile automatically if needed.
+   content << "\n\n";
+
+   controlContent = content.str();
+   if (Section.Scan(controlContent.c_str(), controlContent.length()) == false)
+      return _error->Error(_("Unable to parse package file %s (%d)"), debFileName.c_str(), 3);
+   return true;
+}
+bool debDebFileRecordParser::Jump(pkgCache::VerFileIterator const &) { return LoadContent(); }
+bool debDebFileRecordParser::Jump(pkgCache::DescFileIterator const &) { return LoadContent(); }
+std::string debDebFileRecordParser::FileName() { return debFileName; }
+
+debDebFileRecordParser::debDebFileRecordParser(std::string FileName) : debRecordParserBase(), d(NULL), debFileName(FileName) {}
+debDebFileRecordParser::~debDebFileRecordParser() {}
diff --git a/apt-pkg/deb/debrecords.h b/apt-pkg/deb/debrecords.h
new file mode 100644
index 0000000..10ef917
--- /dev/null
+++ b/apt-pkg/deb/debrecords.h
@@ -0,0 +1,89 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Debian Package Records - Parser for debian package records
+   
+   This provides display-type parsing for the Packages file. This is
+   different than the list parser which provides cache generation
+   services. There should be no overlap between these two.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBRECORDS_H
+#define PKGLIB_DEBRECORDS_H
+
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+#include <apt-pkg/tagfile.h>
+
+#include <string>
+
+
+class APT_HIDDEN debRecordParserBase : public pkgRecords::Parser
+{
+   void * const d;
+ protected:
+   pkgTagSection Section;
+
+ public:
+   // These refer to the archive file for the Version
+   virtual std::string FileName() APT_OVERRIDE;
+   virtual std::string SourcePkg() APT_OVERRIDE;
+   virtual std::string SourceVer() APT_OVERRIDE;
+
+   virtual HashStringList Hashes() const APT_OVERRIDE;
+
+   // These are some general stats about the package
+   virtual std::string Maintainer() APT_OVERRIDE;
+   virtual std::string ShortDesc(std::string const &lang) APT_OVERRIDE;
+   virtual std::string LongDesc(std::string const &lang) APT_OVERRIDE;
+   virtual std::string Name() APT_OVERRIDE;
+   virtual std::string Homepage() APT_OVERRIDE;
+
+   // An arbitrary custom field
+   virtual std::string RecordField(const char *fieldName) APT_OVERRIDE;
+
+   virtual void GetRec(const char *&Start,const char *&Stop) APT_OVERRIDE;
+
+   debRecordParserBase();
+   virtual ~debRecordParserBase();
+};
+
+class APT_HIDDEN debRecordParser : public debRecordParserBase
+{
+   void * const d;
+ protected:
+   FileFd File;
+   pkgTagFile Tags;
+
+   virtual bool Jump(pkgCache::VerFileIterator const &Ver) APT_OVERRIDE;
+   virtual bool Jump(pkgCache::DescFileIterator const &Desc) APT_OVERRIDE;
+
+ public:
+   debRecordParser(std::string FileName,pkgCache &Cache);
+   virtual ~debRecordParser();
+};
+
+// custom record parser that reads deb files directly
+class APT_HIDDEN debDebFileRecordParser : public debRecordParserBase
+{
+   void * const d;
+   std::string debFileName;
+   std::string controlContent;
+
+   APT_HIDDEN bool LoadContent();
+ protected:
+   // single file files, so no jumping whatsoever
+   bool Jump(pkgCache::VerFileIterator const &) APT_OVERRIDE;
+   bool Jump(pkgCache::DescFileIterator const &) APT_OVERRIDE;
+
+ public:
+   virtual std::string FileName() APT_OVERRIDE;
+
+   explicit debDebFileRecordParser(std::string FileName);
+   virtual ~debDebFileRecordParser();
+};
+
+#endif
diff --git a/apt-pkg/deb/debsrcrecords.cc b/apt-pkg/deb/debsrcrecords.cc
new file mode 100644
index 0000000..311bacf
--- /dev/null
+++ b/apt-pkg/deb/debsrcrecords.cc
@@ -0,0 +1,281 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Debian Source Package Records - Parser implementation for Debian style
+                                   source indexes
+      
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/debsrcrecords.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/srcrecords.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <string>
+#include <sstream>
+#include <vector>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+									/*}}}*/
+
+using std::max;
+using std::string;
+
+debSrcRecordParser::debSrcRecordParser(std::string const &File,pkgIndexFile const *Index)
+   : Parser(Index), d(NULL), Tags(&Fd), iOffset(0), Buffer(NULL)
+{
+   if (File.empty() == false)
+   {
+      if (Fd.Open(File, FileFd::ReadOnly, FileFd::Extension))
+	 Tags.Init(&Fd, 102400);
+   }
+}
+std::string debSrcRecordParser::Package() const				/*{{{*/
+{
+   auto const name = Sect.Find(pkgTagSection::Key::Package);
+   if (iIndex != nullptr || name.empty() == false)
+      return name.to_string();
+   return Sect.Find(pkgTagSection::Key::Source).to_string();
+}
+									/*}}}*/
+// SrcRecordParser::Binaries - Return the binaries field		/*{{{*/
+// ---------------------------------------------------------------------
+/* This member parses the binaries field into a pair of class arrays and
+   returns a list of strings representing all of the components of the
+   binaries field. The returned array need not be freed and will be
+   reused by the next Binaries function call. This function is commonly
+   used during scanning to find the right package */
+const char **debSrcRecordParser::Binaries()
+{
+   const char *Start, *End;
+   if (Sect.Find(pkgTagSection::Key::Binary, Start, End) == false)
+      return NULL;
+   for (; isspace_ascii(*Start) != 0; ++Start);
+   if (Start >= End)
+      return NULL;
+
+   StaticBinList.clear();
+   free(Buffer);
+   Buffer = strndup(Start, End - Start);
+
+   char* bin = Buffer;
+   do {
+      char* binStartNext = strchrnul(bin, ',');
+      // Found a comma, clean up any space before it
+      if (binStartNext > Buffer) {
+	 char* binEnd = binStartNext - 1;
+	 for (; binEnd > Buffer && isspace_ascii(*binEnd) != 0; --binEnd)
+	    *binEnd = 0;
+      }
+      StaticBinList.push_back(bin);
+      if (*binStartNext != ',')
+	 break;
+      *binStartNext = '\0';
+      for (bin = binStartNext + 1; isspace_ascii(*bin) != 0; ++bin)
+         ;
+   } while (*bin != '\0');
+   StaticBinList.push_back(NULL);
+
+   return &StaticBinList[0];
+}
+									/*}}}*/
+// SrcRecordParser::BuildDepends - Return the Build-Depends information	/*{{{*/
+// ---------------------------------------------------------------------
+/* This member parses the build-depends information and returns a list of 
+   package/version records representing the build dependency. The returned 
+   array need not be freed and will be reused by the next call to this 
+   function */
+bool debSrcRecordParser::BuildDepends(std::vector<pkgSrcRecords::Parser::BuildDepRec> &BuildDeps,
+					bool const &ArchOnly, bool const &StripMultiArch)
+{
+   BuildDeps.clear();
+
+   pkgTagSection::Key const fields[] = {
+      pkgTagSection::Key::Build_Depends,
+      pkgTagSection::Key::Build_Depends_Indep,
+      pkgTagSection::Key::Build_Conflicts,
+      pkgTagSection::Key::Build_Conflicts_Indep,
+      pkgTagSection::Key::Build_Depends_Arch,
+      pkgTagSection::Key::Build_Conflicts_Arch,
+   };
+   for (unsigned short I = 0; I < sizeof(fields) / sizeof(fields[0]); ++I)
+   {
+      if (ArchOnly && (fields[I] == pkgTagSection::Key::Build_Depends_Indep || fields[I] == pkgTagSection::Key::Build_Conflicts_Indep))
+	 continue;
+
+      const char *Start, *Stop;
+      if (Sect.Find(fields[I], Start, Stop) == false)
+         continue;
+
+      if (Start == Stop)
+	 continue;
+
+      while (1)
+      {
+	 // Strip off leading spaces (is done by ParseDepends, too) and
+	 // superfluous commas (encountered in user-written dsc/control files)
+	 do {
+	    for (;Start != Stop && isspace_ascii(*Start) != 0; ++Start);
+	 } while (*Start == ',' && ++Start != Stop);
+	 if (Start == Stop)
+	    break;
+
+	 BuildDepRec rec;
+	 Start = debListParser::ParseDepends(Start, Stop,
+					     rec.Package, rec.Version, rec.Op, true, StripMultiArch, true);
+
+	 if (Start == 0)
+	    return _error->Error("Problem parsing dependency: %s", BuildDepType(I));
+	 rec.Type = I;
+
+	 // We parsed a package that was ignored (wrong architecture restriction
+	 // or something).
+	 if (rec.Package.empty())
+	 {
+	    // If this was the last or-group member, close the or-group with the previous entry
+	    if (not BuildDeps.empty() && (BuildDeps.back().Op & pkgCache::Dep::Or) == pkgCache::Dep::Or && (rec.Op & pkgCache::Dep::Or) != pkgCache::Dep::Or)
+	       BuildDeps.back().Op &= ~pkgCache::Dep::Or;
+	 } else {
+	    BuildDeps.emplace_back(std::move(rec));
+	 }
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+// SrcRecordParser::Files - Return a list of files for this source	/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses the list of files and returns it, each file is required to have
+   a complete source package */
+bool debSrcRecordParser::Files(std::vector<pkgSrcRecords::File> &List)
+{
+   List.clear();
+
+   // Stash the / terminated directory prefix
+   std::string Base = Sect.Find(pkgTagSection::Key::Directory).to_string();
+   if (Base.empty() == false && Base[Base.length()-1] != '/')
+      Base += '/';
+
+   std::vector<std::string> const compExts = APT::Configuration::getCompressorExtensions();
+
+   auto const &posix = std::locale::classic();
+   for (auto const hashinfo : HashString::SupportedHashesInfo())
+   {
+      auto const Files = Sect.Find(hashinfo.chksumskey);
+      if (Files.empty() == true)
+	 continue;
+      std::istringstream ss(Files.to_string());
+      ss.imbue(posix);
+
+      while (ss.good())
+      {
+	 std::string hash, path;
+	 unsigned long long size;
+	 if (iIndex == nullptr && hashinfo.chksumskey == pkgTagSection::Key::Files)
+	 {
+	    std::string ignore;
+	    ss >> hash >> size >> ignore >> ignore >> path;
+	 }
+	 else
+	    ss >> hash >> size >> path;
+
+	 if (ss.fail() || hash.empty() || path.empty())
+	    return _error->Error("Error parsing file record in %s of source package %s", hashinfo.chksumsname.to_string().c_str(), Package().c_str());
+
+	 HashString const hashString(hashinfo.name.to_string(), hash);
+	 if (Base.empty() == false)
+	    path = Base + path;
+
+	 // look if we have a record for this file already
+	 std::vector<pkgSrcRecords::File>::iterator file = List.begin();
+	 for (; file != List.end(); ++file)
+	    if (file->Path == path)
+	       break;
+
+	 // we have it already, store the new hash and be done
+	 if (file != List.end())
+	 {
+	    // an error here indicates that we have two different hashes for the same file
+	    if (file->Hashes.push_back(hashString) == false)
+	       return _error->Error("Error parsing checksum in %s of source package %s", hashinfo.chksumsname.to_string().c_str(), Package().c_str());
+	    continue;
+	 }
+
+	 // we haven't seen this file yet
+	 pkgSrcRecords::File F;
+	 F.Path = path;
+	 F.FileSize = size;
+	 F.Hashes.push_back(hashString);
+	 F.Hashes.FileSize(F.FileSize);
+
+	 // Try to guess what sort of file it is we are getting.
+	 string::size_type Pos = F.Path.length()-1;
+	 while (1)
+	 {
+	    string::size_type Tmp = F.Path.rfind('.',Pos);
+	    if (Tmp == string::npos)
+	       break;
+	    if (F.Type == "tar") {
+	       // source v3 has extension 'debian.tar.*' instead of 'diff.*'
+	       if (string(F.Path, Tmp+1, Pos-Tmp) == "debian")
+		  F.Type = "diff";
+	       break;
+	    }
+	    F.Type = string(F.Path,Tmp+1,Pos-Tmp);
+
+	    if (std::find(compExts.begin(), compExts.end(), std::string(".").append(F.Type)) != compExts.end() ||
+		  F.Type == "tar")
+	    {
+	       Pos = Tmp-1;
+	       continue;
+	    }
+
+	    break;
+	 }
+	 List.push_back(F);
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+// SrcRecordParser::~SrcRecordParser - Destructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+debSrcRecordParser::~debSrcRecordParser()
+{
+   // was allocated via strndup()
+   free(Buffer);
+}
+									/*}}}*/
+
+
+debDscRecordParser::debDscRecordParser(std::string const &DscFile, pkgIndexFile const *Index)
+   : debSrcRecordParser("", Index)
+{
+   // support clear signed files
+   if (OpenMaybeClearSignedFile(DscFile, Fd) == false)
+   {
+      _error->Error("Failed to open %s", DscFile.c_str());
+      return;
+   }
+
+   // re-init to ensure the updated Fd is used
+   Tags.Init(&Fd, pkgTagFile::SUPPORT_COMMENTS);
+   // read the first (and only) record
+   Step();
+
+}
diff --git a/apt-pkg/deb/debsrcrecords.h b/apt-pkg/deb/debsrcrecords.h
new file mode 100644
index 0000000..1a0bbe0
--- /dev/null
+++ b/apt-pkg/deb/debsrcrecords.h
@@ -0,0 +1,68 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Debian Source Package Records - Parser implementation for Debian style
+                                   source indexes
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBSRCRECORDS_H
+#define PKGLIB_DEBSRCRECORDS_H
+
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/srcrecords.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <string>
+#include <vector>
+#include <stddef.h>
+
+class pkgIndexFile;
+
+class APT_HIDDEN debSrcRecordParser : public pkgSrcRecords::Parser
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+ protected:
+   FileFd Fd;
+   pkgTagFile Tags;
+   pkgTagSection Sect;
+   std::vector<const char*> StaticBinList;
+   unsigned long iOffset;
+   char *Buffer;
+   
+   public:
+
+   virtual bool Restart() APT_OVERRIDE {return Jump(0);};
+   virtual bool Step() APT_OVERRIDE {iOffset = Tags.Offset(); return Tags.Step(Sect);};
+   virtual bool Jump(unsigned long const &Off) APT_OVERRIDE {iOffset = Off; return Tags.Jump(Sect,Off);};
+
+   virtual std::string Package() const APT_OVERRIDE;
+   virtual std::string Version() const APT_OVERRIDE {return Sect.Find(pkgTagSection::Key::Version).to_string();};
+   virtual std::string Maintainer() const APT_OVERRIDE {return Sect.Find(pkgTagSection::Key::Maintainer).to_string();};
+   virtual std::string Section() const APT_OVERRIDE {return Sect.Find(pkgTagSection::Key::Section).to_string();};
+   virtual const char **Binaries() APT_OVERRIDE;
+   virtual bool BuildDepends(std::vector<BuildDepRec> &BuildDeps, bool const &ArchOnly, bool const &StripMultiArch = true) APT_OVERRIDE;
+   virtual unsigned long Offset() APT_OVERRIDE {return iOffset;};
+   virtual std::string AsStr() APT_OVERRIDE 
+   {
+      const char *Start=0,*Stop=0;
+      Sect.GetSection(Start,Stop);
+      return std::string(Start,Stop);
+   };
+   virtual bool Files(std::vector<pkgSrcRecords::File> &F) APT_OVERRIDE;
+
+   debSrcRecordParser(std::string const &File,pkgIndexFile const *Index);
+   virtual ~debSrcRecordParser();
+};
+
+class APT_HIDDEN debDscRecordParser : public debSrcRecordParser
+{
+ public:
+   debDscRecordParser(std::string const &DscFile, pkgIndexFile const *Index);
+};
+
+#endif
diff --git a/apt-pkg/deb/debsystem.cc b/apt-pkg/deb/debsystem.cc
new file mode 100644
index 0000000..9c55e0a
--- /dev/null
+++ b/apt-pkg/deb/debsystem.cc
@@ -0,0 +1,557 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   System - Abstraction for running on different systems.
+
+   Basic general structure..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debindexfile.h>
+#include <apt-pkg/debsystem.h>
+#include <apt-pkg/debversion.h>
+#include <apt-pkg/dpkgpm.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/progress.h>
+
+#include <algorithm>
+#include <sstream>
+
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+debSystem debSys;
+
+class APT_HIDDEN debSystemPrivate {
+public:
+   debSystemPrivate() : FrontendLockFD(-1), LockFD(-1), LockCount(0), StatusFile(0)
+   {
+   }
+   // For locking support
+   int FrontendLockFD;
+   int LockFD;
+   unsigned LockCount;
+   
+   debStatusIndex *StatusFile;
+};
+
+// System::debSystem - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+debSystem::debSystem() : pkgSystem("Debian dpkg interface", &debVS), d(new debSystemPrivate())
+{
+}
+									/*}}}*/
+// System::~debSystem - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+debSystem::~debSystem()
+{
+   delete d->StatusFile;
+   delete d;
+}
+									/*}}}*/
+// System::Lock - Get the lock						/*{{{*/
+// ---------------------------------------------------------------------
+/* This mirrors the operations dpkg does when it starts up. Note the
+   checking of the updates directory. */
+static int GetLockMaybeWait(std::string const &file, OpProgress *Progress, int &timeoutSec)
+{
+   struct ScopedAbsoluteProgress
+   {
+      ScopedAbsoluteProgress() { _config->Set("APT::Internal::OpProgress::Absolute", true); }
+      ~ScopedAbsoluteProgress() { _config->Set("APT::Internal::OpProgress::Absolute", false); }
+   } _scopedAbsoluteProgress;
+   int fd = -1;
+   if (timeoutSec == 0 || Progress == nullptr)
+      return GetLock(file);
+
+   if (_config->FindB("Debug::Locking", false))
+      std::cerr << "Lock: " << file << " wait " << timeoutSec << std::endl;
+
+   for (int i = 0; timeoutSec < 0 || i < timeoutSec; i++)
+   {
+      _error->PushToStack();
+      fd = GetLock(file);
+      if (fd != -1 || errno == EPERM)
+      {
+	 if (timeoutSec > 0)
+	    timeoutSec -= i;
+	 _error->MergeWithStack();
+	 return fd;
+      }
+      std::string poppedError;
+      std::string completeError;
+      _error->PopMessage(poppedError);
+      _error->RevertToStack();
+
+      strprintf(completeError, _("Waiting for cache lock: %s"), poppedError.c_str());
+      sleep(1);
+      Progress->OverallProgress(i, timeoutSec, 0, completeError);
+   }
+
+   if (timeoutSec > 0)
+      timeoutSec = 1;
+   return fd;
+}
+
+bool debSystem::Lock(OpProgress *const Progress)
+{
+   // Disable file locking
+   if (_config->FindB("Debug::NoLocking",false) == true || d->LockCount > 0)
+   {
+      d->LockCount++;
+      return true;
+   }
+
+   // This will count downwards.
+   int lockTimeOutSec = _config->FindI("DPkg::Lock::Timeout", 0);
+   // Create the lockfile
+   string AdminDir = flNotFile(_config->FindFile("Dir::State::status"));
+   string FrontendLockFile = AdminDir + "lock-frontend";
+   d->FrontendLockFD = GetLockMaybeWait(FrontendLockFile, Progress, lockTimeOutSec);
+   if (d->FrontendLockFD == -1)
+   {
+      if (errno == EACCES || errno == EAGAIN)
+	 return _error->Error(_("Unable to acquire the dpkg frontend lock (%s), "
+	                        "is another process using it?"),FrontendLockFile.c_str());
+      else
+	 return _error->Error(_("Unable to acquire the dpkg frontend lock (%s), "
+	                        "are you root?"),FrontendLockFile.c_str());
+   }
+   if (LockInner(Progress, lockTimeOutSec) == false)
+   {
+      close(d->FrontendLockFD);
+      return false;
+   }
+   
+   // See if we need to abort with a dirty journal
+   if (CheckUpdates() == true)
+   {
+      close(d->LockFD);
+      close(d->FrontendLockFD);
+      d->FrontendLockFD = -1;
+      d->LockFD = -1;
+      const char *cmd;
+      if (getenv("SUDO_USER") != NULL)
+	 cmd = "sudo dpkg --configure -a";
+      else
+	 cmd = "dpkg --configure -a";
+      // TRANSLATORS: the %s contains the recovery command, usually
+      //              dpkg --configure -a
+      return _error->Error(_("dpkg was interrupted, you must manually "
+                             "run '%s' to correct the problem. "), cmd);
+   }
+
+	 d->LockCount++;
+      
+   return true;
+}
+
+bool debSystem::LockInner(OpProgress *const Progress, int timeOutSec)
+{
+   string AdminDir = flNotFile(_config->FindFile("Dir::State::status"));
+   d->LockFD = GetLockMaybeWait(AdminDir + "lock", Progress, timeOutSec);
+   if (d->LockFD == -1)
+   {
+      if (errno == EACCES || errno == EAGAIN)
+	 return _error->Error(_("Unable to lock the administration directory (%s), "
+	                        "is another process using it?"),AdminDir.c_str());
+      else
+	 return _error->Error(_("Unable to lock the administration directory (%s), "
+	                        "are you root?"),AdminDir.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// System::UnLock - Drop a lock						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debSystem::UnLock(bool NoErrors)
+{
+   if (d->LockCount == 0 && NoErrors == true)
+      return false;
+   
+   if (d->LockCount < 1)
+      return _error->Error(_("Not locked"));
+   if (--d->LockCount == 0)
+   {
+      close(d->LockFD);
+      close(d->FrontendLockFD);
+      d->LockCount = 0;
+   }
+   
+   return true;
+}
+bool debSystem::UnLockInner(bool NoErrors) {
+   (void) NoErrors;
+   close(d->LockFD);
+   return true;
+}
+									/*}}}*/
+// System::IsLocked - Check if system is locked						/*{{{*/
+// ---------------------------------------------------------------------
+/* This checks if the frontend lock is hold. The inner lock might be
+ * released. */
+bool debSystem::IsLocked()
+{
+   return d->LockCount > 0;
+}
+									/*}}}*/
+// System::CheckUpdates - Check if the updates dir is dirty		/*{{{*/
+// ---------------------------------------------------------------------
+/* This does a check of the updates directory (dpkg journal) to see if it has 
+   any entries in it. */
+bool debSystem::CheckUpdates()
+{
+   // Check for updates.. (dirty)
+   string File = flNotFile(_config->FindFile("Dir::State::status")) + "updates/";
+   DIR *DirP = opendir(File.c_str());
+   if (DirP == 0)
+      return false;
+   
+   /* We ignore any files that are not all digits, this skips .,.. and 
+      some tmp files dpkg will leave behind.. */
+   bool Damaged = false;
+   for (struct dirent *Ent = readdir(DirP); Ent != 0; Ent = readdir(DirP))
+   {
+      Damaged = true;
+      for (unsigned int I = 0; Ent->d_name[I] != 0; I++)
+      {
+	 // Check if its not a digit..
+	 if (isdigit(Ent->d_name[I]) == 0)
+	 {
+	    Damaged = false;
+	    break;
+	 }
+      }
+      if (Damaged == true)
+	 break;
+   }
+   closedir(DirP);
+
+   return Damaged;
+}
+									/*}}}*/
+// System::CreatePM - Create the underlying package manager		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgPackageManager *debSystem::CreatePM(pkgDepCache *Cache) const
+{
+   return new pkgDPkgPM(Cache);
+}
+									/*}}}*/
+// System::Initialize - Setup the configuration space..			/*{{{*/
+// ---------------------------------------------------------------------
+/* These are the Debian specific configuration variables.. */
+static std::string getDpkgStatusLocation(Configuration const &Cnf) {
+   Configuration PathCnf;
+   PathCnf.Set("Dir", Cnf.Find("Dir", "/"));
+   PathCnf.Set("Dir::State::status", "status");
+   auto const cnfstatedir = Cnf.Find("Dir::State", &STATE_DIR[1]);
+   // if the state dir ends in apt, replace it with dpkg -
+   // for the default this gives us the same as the fallback below.
+   // This can't be a ../dpkg as that would play bad with symlinks
+   std::string statedir;
+   if (APT::String::Endswith(cnfstatedir, "/apt/"))
+      statedir.assign(cnfstatedir, 0, cnfstatedir.length() - 5);
+   else if (APT::String::Endswith(cnfstatedir, "/apt"))
+      statedir.assign(cnfstatedir, 0, cnfstatedir.length() - 4);
+   if (statedir.empty())
+      PathCnf.Set("Dir::State", "var/lib/dpkg");
+   else
+      PathCnf.Set("Dir::State", flCombine(statedir, "dpkg"));
+   return PathCnf.FindFile("Dir::State::status");
+}
+bool debSystem::Initialize(Configuration &Cnf)
+{
+   /* These really should be jammed into a generic 'Local Database' engine
+      which is yet to be determined. The functions in pkgcachegen should
+      be the only users of these */
+   Cnf.CndSet("Dir::State::extended_states", "extended_states");
+   if (Cnf.Exists("Dir::State::status") == false)
+      Cnf.Set("Dir::State::status", getDpkgStatusLocation(Cnf));
+   Cnf.CndSet("Dir::Bin::dpkg",BIN_DIR"/dpkg");
+
+   if (d->StatusFile) {
+     delete d->StatusFile;
+     d->StatusFile = 0;
+   }
+
+   return true;
+}
+									/*}}}*/
+// System::ArchiveSupported - Is a file format supported		/*{{{*/
+// ---------------------------------------------------------------------
+/* The standard name for a deb is 'deb'.. There are no separate versions
+   of .deb to worry about.. */
+APT_PURE bool debSystem::ArchiveSupported(const char *Type)
+{
+   if (strcmp(Type,"deb") == 0)
+      return true;
+   return false;
+}
+									/*}}}*/
+// System::Score - Determine how 'Debiany' this sys is..		/*{{{*/
+// ---------------------------------------------------------------------
+/* We check some files that are sure tell signs of this being a Debian
+   System.. */
+signed debSystem::Score(Configuration const &Cnf)
+{
+   signed Score = 0;
+   if (FileExists(Cnf.FindFile("Dir::State::status",getDpkgStatusLocation(Cnf).c_str())) == true)
+       Score += 10;
+   if (FileExists(Cnf.Find("Dir::Bin::dpkg",BIN_DIR"/dpkg")) == true)
+      Score += 10;
+   if (FileExists("/etc/debian_version") == true)
+      Score += 10;
+   return Score;
+}
+									/*}}}*/
+// System::AddStatusFiles - Register the status files			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debSystem::AddStatusFiles(std::vector<pkgIndexFile *> &List)
+{
+   if (d->StatusFile == nullptr)
+   {
+      auto dpkgstatus = _config->FindFile("Dir::State::status");
+      if (dpkgstatus.empty())
+	 return true;
+      // we ignore only if the file doesn't exist, not if it is inaccessible
+      // e.g. due to permissions on parent directories as FileExists would do
+      errno = 0;
+      if (access(dpkgstatus.c_str(), R_OK) != 0 && errno == ENOENT)
+	 return true;
+      _error->PushToStack();
+      d->StatusFile = new debStatusIndex(std::move(dpkgstatus));
+      bool const errored = _error->PendingError();
+      _error->MergeWithStack();
+      if (errored)
+      {
+	 delete d->StatusFile;
+	 d->StatusFile = nullptr;
+	 return false;
+      }
+   }
+   List.push_back(d->StatusFile);
+   return true;
+}
+									/*}}}*/
+// System::FindIndex - Get an index file for status files		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool debSystem::FindIndex(pkgCache::PkgFileIterator File,
+			  pkgIndexFile *&Found) const
+{
+   if (d->StatusFile == 0)
+      return false;
+   if (d->StatusFile->FindInCache(*File.Cache()) == File)
+   {
+      Found = d->StatusFile;
+      return true;
+   }
+   
+   return false;
+}
+									/*}}}*/
+std::string debSystem::StripDpkgChrootDirectory(std::string const &File)/*{{{*/
+{
+   // If the filename string begins with DPkg::Chroot-Directory, return the
+   // substr that is within the chroot so dpkg can access it.
+   std::string const chrootdir = _config->FindDir("DPkg::Chroot-Directory","/");
+   size_t len = chrootdir.length();
+   if (chrootdir == "/" || File.compare(0, len, chrootdir) != 0)
+      return File;
+   if (chrootdir.at(len - 1) == '/')
+      --len;
+   return File.substr(len);
+}
+									/*}}}*/
+std::string debSystem::GetDpkgExecutable()				/*{{{*/
+{
+   return StripDpkgChrootDirectory(_config->Find("Dir::Bin::dpkg","dpkg"));
+}
+									/*}}}*/
+std::vector<std::string> debSystem::GetDpkgBaseCommand()		/*{{{*/
+{
+   // Generate the base argument list for dpkg
+   std::vector<std::string> Args = { GetDpkgExecutable() };
+   // Stick in any custom dpkg options
+   Configuration::Item const *Opts = _config->Tree("DPkg::Options");
+   if (Opts != 0)
+   {
+      Opts = Opts->Child;
+      for (; Opts != 0; Opts = Opts->Next)
+      {
+	 if (Opts->Value.empty() == true)
+	    continue;
+	 Args.push_back(Opts->Value);
+      }
+   }
+   return Args;
+}
+									/*}}}*/
+void debSystem::DpkgChrootDirectory()					/*{{{*/
+{
+   std::string const chrootDir = _config->FindDir("DPkg::Chroot-Directory");
+   if (chrootDir == "/")
+      return;
+   std::cerr << "Chrooting into " << chrootDir << std::endl;
+   if (chroot(chrootDir.c_str()) != 0)
+      _exit(100);
+   if (chdir("/") != 0)
+      _exit(100);
+}
+									/*}}}*/
+pid_t debSystem::ExecDpkg(std::vector<std::string> const &sArgs, int * const inputFd, int * const outputFd, bool const DiscardOutput)/*{{{*/
+{
+   std::vector<const char *> Args(sArgs.size(), NULL);
+   std::transform(sArgs.begin(), sArgs.end(), Args.begin(), [](std::string const &s) { return s.c_str(); });
+   Args.push_back(NULL);
+
+   int external[2] = {-1, -1};
+   if (inputFd != nullptr || outputFd != nullptr)
+      if (pipe(external) != 0)
+      {
+	 _error->WarningE("dpkg", "Can't create IPC pipe for dpkg call");
+	 return -1;
+      }
+
+   pid_t const dpkg = ExecFork();
+   if (dpkg == 0) {
+      int const nullfd = open("/dev/null", O_RDWR);
+      if (inputFd == nullptr)
+	 dup2(nullfd, STDIN_FILENO);
+      else
+      {
+	 close(external[1]);
+	 dup2(external[0], STDIN_FILENO);
+      }
+      if (outputFd == nullptr)
+	 dup2(nullfd, STDOUT_FILENO);
+      else
+      {
+	 close(external[0]);
+	 dup2(external[1], STDOUT_FILENO);
+      }
+      if (DiscardOutput == true)
+	 dup2(nullfd, STDERR_FILENO);
+      debSystem::DpkgChrootDirectory();
+
+      if (_system != nullptr && _system->IsLocked() == true)
+      {
+	 setenv("DPKG_FRONTEND_LOCKED", "true", 1);
+      }
+
+      if (_config->Find("DPkg::Path", "").empty() == false)
+	 setenv("PATH", _config->Find("DPkg::Path", "").c_str(), 1);
+
+      execvp(Args[0], (char**) &Args[0]);
+      _error->WarningE("dpkg", "Can't execute dpkg!");
+      _exit(100);
+   }
+   if (outputFd != nullptr)
+   {
+      close(external[1]);
+      *outputFd = external[0];
+   }
+   else if (inputFd != nullptr)
+   {
+      close(external[0]);
+      *inputFd = external[1];
+   }
+   return dpkg;
+}
+									/*}}}*/
+bool debSystem::MultiArchSupported() const					/*{{{*/
+{
+   return AssertFeature("multi-arch");
+}
+									/*}}}*/
+bool debSystem::AssertFeature(std::string const &feature) /*{{{*/
+{
+   std::vector<std::string> Args = GetDpkgBaseCommand();
+   Args.push_back("--assert-" + feature);
+   pid_t const dpkgAssertMultiArch = ExecDpkg(Args, nullptr, nullptr, true);
+   if (dpkgAssertMultiArch > 0)
+   {
+      int Status = 0;
+      while (waitpid(dpkgAssertMultiArch, &Status, 0) != dpkgAssertMultiArch)
+      {
+	 if (errno == EINTR)
+	    continue;
+	 _error->WarningE("dpkgGo", _("Waited for %s but it wasn't there"), "dpkg --assert-multi-arch");
+	 break;
+      }
+      if (WIFEXITED(Status) == true && WEXITSTATUS(Status) == 0)
+	 return true;
+   }
+   return false;
+}
+									/*}}}*/
+std::vector<std::string> debSystem::ArchitecturesSupported() const		/*{{{*/
+{
+   std::vector<std::string> archs;
+   {
+      string const arch = _config->Find("APT::Architecture");
+      if (arch.empty() == false)
+	 archs.push_back(std::move(arch));
+   }
+
+   std::vector<std::string> sArgs = GetDpkgBaseCommand();
+   sArgs.push_back("--print-foreign-architectures");
+   int outputFd = -1;
+   pid_t const dpkgMultiArch = ExecDpkg(sArgs, nullptr, &outputFd, true);
+   if (dpkgMultiArch == -1)
+      return archs;
+
+   FILE *dpkg = fdopen(outputFd, "r");
+   if(dpkg != NULL) {
+      char* buf = NULL;
+      size_t bufsize = 0;
+      while (getline(&buf, &bufsize, dpkg) != -1)
+      {
+	 char* tok_saveptr;
+	 char* arch = strtok_r(buf, " ", &tok_saveptr);
+	 while (arch != NULL) {
+	    for (; isspace_ascii(*arch) != 0; ++arch);
+	    if (arch[0] != '\0') {
+	       char const* archend = arch;
+	       for (; isspace_ascii(*archend) == 0 && *archend != '\0'; ++archend);
+	       string a(arch, (archend - arch));
+	       if (std::find(archs.begin(), archs.end(), a) == archs.end())
+		  archs.push_back(a);
+	    }
+	    arch = strtok_r(NULL, " ", &tok_saveptr);
+	 }
+      }
+      free(buf);
+      fclose(dpkg);
+   }
+   ExecWait(dpkgMultiArch, "dpkg --print-foreign-architectures", true);
+   return archs;
+}
+									/*}}}*/
diff --git a/apt-pkg/deb/debsystem.h b/apt-pkg/deb/debsystem.h
new file mode 100644
index 0000000..c426faf
--- /dev/null
+++ b/apt-pkg/deb/debsystem.h
@@ -0,0 +1,59 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   System - Debian version of the  System Class
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBSYSTEM_H
+#define PKGLIB_DEBSYSTEM_H
+
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgsystem.h>
+
+#include <vector>
+class Configuration;
+class pkgIndexFile;
+class pkgPackageManager;
+class debSystemPrivate;
+class pkgDepCache;
+
+
+class debSystem : public pkgSystem
+{
+   // private d-pointer
+   debSystemPrivate * const d;
+   APT_HIDDEN bool CheckUpdates();
+
+   public:
+   virtual bool Lock(OpProgress *const Progress) APT_OVERRIDE;
+   virtual bool UnLock(bool NoErrors = false) APT_OVERRIDE;
+   virtual pkgPackageManager *CreatePM(pkgDepCache *Cache) const APT_OVERRIDE;
+   virtual bool Initialize(Configuration &Cnf) APT_OVERRIDE;
+   virtual bool ArchiveSupported(const char *Type) APT_OVERRIDE;
+   virtual signed Score(Configuration const &Cnf) APT_OVERRIDE;
+   virtual bool AddStatusFiles(std::vector<pkgIndexFile *> &List) APT_OVERRIDE;
+   virtual bool FindIndex(pkgCache::PkgFileIterator File,
+			  pkgIndexFile *&Found) const APT_OVERRIDE;
+
+   debSystem();
+   virtual ~debSystem();
+
+   APT_HIDDEN static std::string GetDpkgExecutable();
+   APT_HIDDEN static std::vector<std::string> GetDpkgBaseCommand();
+   APT_HIDDEN static void DpkgChrootDirectory();
+   APT_HIDDEN static std::string StripDpkgChrootDirectory(std::string const &File);
+   APT_HIDDEN static pid_t ExecDpkg(std::vector<std::string> const &sArgs, int * const inputFd, int * const outputFd, bool const DiscardOutput);
+   bool MultiArchSupported() const override;
+   static bool AssertFeature(std::string const &Feature);
+   std::vector<std::string> ArchitecturesSupported() const override;
+
+   bool LockInner(OpProgress *const Progress, int timeoutSec) override;
+   bool UnLockInner(bool NoErrors=false) override;
+   bool IsLocked() override;
+};
+
+extern debSystem debSys;
+
+#endif
diff --git a/apt-pkg/deb/debversion.cc b/apt-pkg/deb/debversion.cc
new file mode 100644
index 0000000..005f1bc
--- /dev/null
+++ b/apt-pkg/deb/debversion.cc
@@ -0,0 +1,279 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Version - Versioning system for Debian
+
+   This implements the standard Debian versioning system.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/debversion.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+									/*}}}*/
+
+debVersioningSystem debVS;
+
+// debVS::debVersioningSystem - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+debVersioningSystem::debVersioningSystem()
+{
+   Label = "Standard .deb";
+}
+									/*}}}*/
+
+// debVS::CmpFragment - Compare versions			        /*{{{*/
+// ---------------------------------------------------------------------
+/* This compares a fragment of the version. This is a slightly adapted
+   version of what dpkg uses in dpkg/lib/dpkg/version.c.
+   In particular, the a | b = NULL check is removed as we check this in the
+   caller, we use an explicit end for a | b strings and we check ~ explicit. */
+static int order(char c)
+{
+   if (isdigit(c))
+      return 0;
+   else if (isalpha_ascii(c))
+      return c;
+   else if (c == '~')
+      return -1;
+   else if (c)
+      return c + 256;
+   else
+      return 0;
+}
+int debVersioningSystem::CmpFragment(const char *A,const char *AEnd,
+				     const char *B,const char *BEnd)
+{
+   /* Iterate over the whole string
+      What this does is to split the whole string into groups of
+      numeric and non numeric portions. For instance:
+         a67bhgs89
+      Has 4 portions 'a', '67', 'bhgs', '89'. A more normal:
+         2.7.2-linux-1
+      Has '2', '.', '7', '.' ,'-linux-','1' */
+   const char *lhs = A;
+   const char *rhs = B;
+   while (lhs != AEnd && rhs != BEnd)
+   {
+      int first_diff = 0;
+
+      while (lhs != AEnd && rhs != BEnd &&
+	     (!isdigit(*lhs) || !isdigit(*rhs)))
+      {
+	 int vc = order(*lhs);
+	 int rc = order(*rhs);
+	 if (vc != rc)
+	    return vc - rc;
+	 ++lhs; ++rhs;
+      }
+
+      while (*lhs == '0')
+	 ++lhs;
+      while (*rhs == '0')
+	 ++rhs;
+      while (isdigit(*lhs) && isdigit(*rhs))
+      {
+	 if (!first_diff)
+	    first_diff = *lhs - *rhs;
+	 ++lhs;
+	 ++rhs;
+      }
+
+      if (isdigit(*lhs))
+	 return 1;
+      if (isdigit(*rhs))
+	 return -1;
+      if (first_diff)
+	 return first_diff;
+   }
+
+   // The strings must be equal
+   if (lhs == AEnd && rhs == BEnd)
+      return 0;
+
+   // lhs is shorter
+   if (lhs == AEnd)
+   {
+      if (*rhs == '~') return 1;
+      return -1;
+   }
+
+   // rhs is shorter
+   if (rhs == BEnd)
+   {
+      if (*lhs == '~') return -1;
+      return 1;
+   }
+
+   // Shouldn't happen
+   return 1;
+}
+									/*}}}*/
+// debVS::CmpVersion - Comparison for versions				/*{{{*/
+// ---------------------------------------------------------------------
+/* This fragments the version into E:V-R triples and compares each 
+   portion separately. */
+int debVersioningSystem::DoCmpVersion(const char *A,const char *AEnd,
+				      const char *B,const char *BEnd)
+{
+   // Strip off the epoch and compare it
+   const char *lhs = (const char*) memchr(A, ':', AEnd - A);
+   const char *rhs = (const char*) memchr(B, ':', BEnd - B);
+   if (lhs == NULL)
+      lhs = A;
+   if (rhs == NULL)
+      rhs = B;
+   
+   // Special case: a zero epoch is the same as no epoch,
+   // so remove it.
+   if (lhs != A)
+   {
+      for (; *A == '0'; ++A);
+      if (A == lhs)
+      {
+	 ++A;
+	 ++lhs;
+      }
+   }
+   if (rhs != B)
+   {
+      for (; *B == '0'; ++B);
+      if (B == rhs)
+      {
+	 ++B;
+	 ++rhs;
+      }
+   }
+
+   // Compare the epoch
+   int Res = CmpFragment(A,lhs,B,rhs);
+   if (Res != 0)
+      return Res;
+
+   // Skip the :
+   if (lhs != A)
+      lhs++;
+   if (rhs != B)
+      rhs++;
+   
+   // Find the last -
+   const char *dlhs = (const char*) memrchr(lhs, '-', AEnd - lhs);
+   const char *drhs = (const char*) memrchr(rhs, '-', BEnd - rhs);
+   if (dlhs == NULL)
+      dlhs = AEnd;
+   if (drhs == NULL)
+      drhs = BEnd;
+   
+   // Compare the main version
+   Res = CmpFragment(lhs,dlhs,rhs,drhs);
+   if (Res != 0)
+      return Res;
+   
+   // Skip the -
+   if (dlhs != lhs)
+      dlhs++;
+   if (drhs != rhs)
+      drhs++;
+
+   // no debian revision need to be treated like -0
+   if (*(dlhs-1) == '-' && *(drhs-1) == '-')
+      return CmpFragment(dlhs,AEnd,drhs,BEnd);
+   else if (*(dlhs-1) == '-')
+   {
+      const char* null = "0";
+      return CmpFragment(dlhs,AEnd,null, null+1);
+   }
+   else if (*(drhs-1) == '-')
+   {
+      const char* null = "0";
+      return CmpFragment(null, null+1, drhs, BEnd);
+   }
+   else
+      return 0;
+}
+									/*}}}*/
+// debVS::CheckDep - Check a single dependency				/*{{{*/
+// ---------------------------------------------------------------------
+/* This simply performs the version comparison and switch based on 
+   operator. If DepVer is 0 then we are comparing against a provides
+   with no version. */
+bool debVersioningSystem::CheckDep(const char *PkgVer,
+				   int Op,const char *DepVer)
+{
+   if (DepVer == 0 || DepVer[0] == 0)
+      return true;
+   if (PkgVer == 0 || PkgVer[0] == 0)
+      return false;
+   Op &= 0x0F;
+
+   // fast track for (equal) strings [by location] which are by definition equal versions
+   if (PkgVer == DepVer)
+      return Op == pkgCache::Dep::Equals || Op == pkgCache::Dep::LessEq || Op == pkgCache::Dep::GreaterEq;
+
+   // Perform the actual comparison.
+   int const Res = CmpVersion(PkgVer, DepVer);
+   switch (Op)
+   {
+      case pkgCache::Dep::LessEq:
+      if (Res <= 0)
+	 return true;
+      break;
+      
+      case pkgCache::Dep::GreaterEq:
+      if (Res >= 0)
+	 return true;
+      break;
+      
+      case pkgCache::Dep::Less:
+      if (Res < 0)
+	 return true;
+      break;
+      
+      case pkgCache::Dep::Greater:
+      if (Res > 0)
+	 return true;
+      break;
+      
+      case pkgCache::Dep::Equals:
+      if (Res == 0)
+	 return true;
+      break;
+      
+      case pkgCache::Dep::NotEquals:
+      if (Res != 0)
+	 return true;
+      break;
+   }
+
+   return false;
+}
+									/*}}}*/
+// debVS::UpstreamVersion - Return the upstream version string		/*{{{*/
+// ---------------------------------------------------------------------
+/* This strips all the debian specific information from the version number */
+std::string debVersioningSystem::UpstreamVersion(const char *Ver)
+{
+   // Strip off the bit before the first colon
+   const char *I = Ver;
+   for (; *I != 0 && *I != ':'; I++);
+   if (*I == ':')
+      Ver = I + 1;
+   
+   // Chop off the trailing -
+   I = Ver;
+   unsigned Last = strlen(Ver);
+   for (; *I != 0; I++)
+      if (*I == '-')
+	 Last = I - Ver;
+   
+   return std::string(Ver,Last);
+}
+									/*}}}*/
diff --git a/apt-pkg/deb/debversion.h b/apt-pkg/deb/debversion.h
new file mode 100644
index 0000000..5c328a9
--- /dev/null
+++ b/apt-pkg/deb/debversion.h
@@ -0,0 +1,41 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Debian Version - Versioning system for Debian
+
+   This implements the standard Debian versioning system.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEBVERSION_H
+#define PKGLIB_DEBVERSION_H
+
+#include <apt-pkg/version.h>
+
+#include <string>
+
+class APT_PUBLIC debVersioningSystem : public pkgVersioningSystem
+{
+   public:
+
+   static int CmpFragment(const char *A, const char *AEnd, const char *B,
+			  const char *BEnd) APT_PURE;
+
+   // Compare versions..
+   virtual int DoCmpVersion(const char *A,const char *Aend,
+			  const char *B,const char *Bend) APT_OVERRIDE APT_PURE;
+   virtual bool CheckDep(const char *PkgVer,int Op,const char *DepVer) APT_OVERRIDE APT_PURE;
+   virtual APT_PURE int DoCmpReleaseVer(const char *A,const char *Aend,
+			     const char *B,const char *Bend) APT_OVERRIDE
+   {
+      return DoCmpVersion(A,Aend,B,Bend);
+   }
+   virtual std::string UpstreamVersion(const char *A) APT_OVERRIDE;
+
+   debVersioningSystem();
+};
+
+extern APT_PUBLIC debVersioningSystem debVS;
+
+#endif
diff --git a/apt-pkg/deb/dpkgpm.cc b/apt-pkg/deb/dpkgpm.cc
new file mode 100644
index 0000000..93effa9
--- /dev/null
+++ b/apt-pkg/deb/dpkgpm.cc
@@ -0,0 +1,2491 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   DPKG Package Manager - Provide an interface to dpkg
+
+   ##################################################################### */
+									/*}}}*/
+// Includes								/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debsystem.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/dpkgpm.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/install-progress.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/statechanges.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/version.h>
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <array>
+#include <cstring>
+#include <iostream>
+#include <map>
+#include <numeric>
+#include <set>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <unordered_set>
+#include <utility>
+#include <vector>
+
+#include <apti18n.h>
+									/*}}}*/
+
+extern char **environ;
+
+using namespace std;
+
+APT_PURE static string AptHistoryRequestingUser()			/*{{{*/
+{
+   const char* EnvKeys[]{"SUDO_UID", "PKEXEC_UID", "PACKAGEKIT_CALLER_UID"};
+
+   for (const auto &Key: EnvKeys)
+   {
+      if (getenv(Key) != nullptr)
+      {
+         int uid = atoi(getenv(Key));
+         if (uid > 0) {
+            struct passwd pwd;
+            struct passwd *result;
+            char buf[255];
+            if (getpwuid_r(uid, &pwd, buf, sizeof(buf), &result) == 0 && result != NULL) {
+               std::string res;
+               strprintf(res, "%s (%d)", pwd.pw_name, uid);
+               return res;
+            }
+         }
+      }
+   }
+   return "";
+}
+									/*}}}*/
+APT_PURE static unsigned int EnvironmentSize()				/*{{{*/
+{
+  unsigned int size = 0;
+  char **envp = environ;
+
+  while (*envp != NULL)
+    size += strlen (*envp++) + 1;
+
+  return size;
+}
+									/*}}}*/
+class pkgDPkgPMPrivate							/*{{{*/
+{
+public:
+   pkgDPkgPMPrivate() : stdin_is_dev_null(false), status_fd_reached_end_of_file(false),
+			dpkgbuf_pos(0), term_out(NULL), history_out(NULL),
+			progress(NULL), tt_is_valid(false), master(-1),
+			slave(NULL), protect_slave_from_dying(-1),
+			direct_stdin(false)
+   {
+      dpkgbuf[0] = '\0';
+   }
+   ~pkgDPkgPMPrivate()
+   {
+   }
+   bool stdin_is_dev_null;
+   bool status_fd_reached_end_of_file;
+   // the buffer we use for the dpkg status-fd reading
+   char dpkgbuf[1024];
+   size_t dpkgbuf_pos;
+   FILE *term_out;
+   FILE *history_out;
+   string dpkg_error;
+   APT::Progress::PackageManager *progress;
+
+   // pty stuff
+   struct termios tt;
+   bool tt_is_valid;
+   int master;
+   char * slave;
+   int protect_slave_from_dying;
+
+   // signals
+   sigset_t sigmask;
+   sigset_t original_sigmask;
+
+   bool direct_stdin;
+};
+									/*}}}*/
+namespace
+{
+  // Maps the dpkg "processing" info to human readable names.  Entry 0
+  // of each array is the key, entry 1 is the value.
+  const std::pair<const char *, const char *> PackageProcessingOps[] = {
+    std::make_pair("install",   N_("Preparing %s")),
+    // we don't care for the difference
+    std::make_pair("upgrade",   N_("Preparing %s")),
+    std::make_pair("configure", N_("Preparing to configure %s")),
+    std::make_pair("remove",    N_("Preparing for removal of %s")),
+    std::make_pair("purge",     N_("Preparing to completely remove %s")),
+    std::make_pair("disappear", N_("Noting disappearance of %s")),
+    std::make_pair("trigproc",  N_("Running post-installation trigger %s"))
+  };
+
+  const std::pair<const char *, const char *> * const PackageProcessingOpsBegin = PackageProcessingOps;
+  const std::pair<const char *, const char *> * const PackageProcessingOpsEnd   = PackageProcessingOps + sizeof(PackageProcessingOps) / sizeof(PackageProcessingOps[0]);
+
+  // Predicate to test whether an entry in the PackageProcessingOps
+  // array matches a string.
+  class MatchProcessingOp
+  {
+    const char *target;
+
+  public:
+    explicit MatchProcessingOp(const char *the_target)
+      : target(the_target)
+    {
+    }
+
+    bool operator()(const std::pair<const char *, const char *> &pair) const
+    {
+      return strcmp(pair.first, target) == 0;
+    }
+  };
+}
+
+// ionice - helper function to ionice the given PID			/*{{{*/
+/* there is no C header for ionice yet - just the syscall interface
+   so we use the binary from util-linux */
+static bool ionice(int PID)
+{
+   if (!FileExists("/usr/bin/ionice"))
+      return false;
+   pid_t Process = ExecFork();
+   if (Process == 0)
+   {
+      char buf[32];
+      snprintf(buf, sizeof(buf), "-p%d", PID);
+      const char *Args[4];
+      Args[0] = "/usr/bin/ionice";
+      Args[1] = "-c3";
+      Args[2] = buf;
+      Args[3] = 0;
+      execv(Args[0], (char **)Args);
+   }
+   return ExecWait(Process, "ionice");
+}
+									/*}}}*/
+// FindNowVersion - Helper to find a Version in "now" state	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is helpful when a package is no longer installed but has residual
+ * config files
+ */
+static
+pkgCache::VerIterator FindNowVersion(const pkgCache::PkgIterator &Pkg)
+{
+   pkgCache::VerIterator Ver;
+   for (Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
+      for (pkgCache::VerFileIterator Vf = Ver.FileList(); Vf.end() == false; ++Vf)
+	 for (pkgCache::PkgFileIterator F = Vf.File(); F.end() == false; ++F)
+	 {
+	    if (F.Archive() != 0 && strcmp(F.Archive(), "now") == 0)
+	       return Ver;
+	 }
+   return Ver;
+}
+									/*}}}*/
+static pkgCache::VerIterator FindToBeRemovedVersion(pkgCache::PkgIterator const &Pkg)/*{{{*/
+{
+   auto const PV = Pkg.CurrentVer();
+   if (PV.end() == false)
+      return PV;
+   return FindNowVersion(Pkg);
+}
+									/*}}}*/
+
+// DPkgPM::pkgDPkgPM - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgDPkgPM::pkgDPkgPM(pkgDepCache *Cache)
+   : pkgPackageManager(Cache),d(new pkgDPkgPMPrivate()), pkgFailures(0), PackagesDone(0), PackagesTotal(0)
+{
+}
+									/*}}}*/
+// DPkgPM::pkgDPkgPM - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgDPkgPM::~pkgDPkgPM()
+{
+   delete d;
+}
+									/*}}}*/
+// DPkgPM::Install - Install a package					/*{{{*/
+// ---------------------------------------------------------------------
+/* Add an install operation to the sequence list */
+bool pkgDPkgPM::Install(PkgIterator Pkg,string File)
+{
+   if (File.empty() == true || Pkg.end() == true)
+      return _error->Error("Internal Error, No file name for %s",Pkg.FullName().c_str());
+
+   List.emplace_back(Item::Install, Pkg, debSystem::StripDpkgChrootDirectory(File));
+   return true;
+}
+									/*}}}*/
+// DPkgPM::Configure - Configure a package				/*{{{*/
+// ---------------------------------------------------------------------
+/* Add a configure operation to the sequence list */
+bool pkgDPkgPM::Configure(PkgIterator Pkg)
+{
+   if (Pkg.end() == true)
+      return false;
+
+   List.push_back(Item(Item::Configure, Pkg));
+
+   // Use triggers for config calls if we configure "smart"
+   // as otherwise Pre-Depends will not be satisfied, see #526774
+   if (_config->FindB("DPkg::TriggersPending", false) == true)
+      List.push_back(Item(Item::TriggersPending, PkgIterator()));
+
+   return true;
+}
+									/*}}}*/
+// DPkgPM::Remove - Remove a package					/*{{{*/
+// ---------------------------------------------------------------------
+/* Add a remove operation to the sequence list */
+bool pkgDPkgPM::Remove(PkgIterator Pkg,bool Purge)
+{
+   if (Pkg.end() == true)
+      return false;
+
+   if (Purge == true)
+      List.push_back(Item(Item::Purge,Pkg));
+   else
+      List.push_back(Item(Item::Remove,Pkg));
+   return true;
+}
+									/*}}}*/
+// DPkgPM::SendPkgInfo - Send info for install-pkgs hook		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is part of the helper script communication interface, it sends
+   very complete information down to the other end of the pipe.*/
+bool pkgDPkgPM::SendPkgsInfo(FILE * const F, unsigned int const &Version)
+{
+   // This version of APT supports only v3, so don't sent higher versions
+   if (Version <= 3)
+      fprintf(F,"VERSION %u\n", Version);
+   else
+      fprintf(F,"VERSION 3\n");
+
+   /* Write out all of the configuration directives by walking the
+      configuration tree */
+   const Configuration::Item *Top = _config->Tree(0);
+   for (; Top != 0;)
+   {
+      if (Top->Value.empty() == false)
+      {
+	 fprintf(F,"%s=%s\n",
+		 QuoteString(Top->FullTag(),"=\"\n").c_str(),
+		 QuoteString(Top->Value,"\n").c_str());
+      }
+
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+	 Top = Top->Parent;
+      if (Top != 0)
+	 Top = Top->Next;
+   }
+   fprintf(F,"\n");
+
+   // Write out the package actions in order.
+   for (vector<Item>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      if(I->Pkg.end() == true)
+	 continue;
+
+      pkgDepCache::StateCache &S = Cache[I->Pkg];
+
+      fprintf(F,"%s ",I->Pkg.Name());
+
+      // Current version which we are going to replace
+      pkgCache::VerIterator CurVer = I->Pkg.CurrentVer();
+      if (CurVer.end() == true && (I->Op == Item::Remove || I->Op == Item::Purge))
+	 CurVer = FindNowVersion(I->Pkg);
+
+      if (CurVer.end() == true)
+      {
+	 if (Version <= 2)
+	    fprintf(F, "- ");
+	 else
+	    fprintf(F, "- - none ");
+      }
+      else
+      {
+	 fprintf(F, "%s ", CurVer.VerStr());
+	 if (Version >= 3)
+	    fprintf(F, "%s %s ", CurVer.Arch(), CurVer.MultiArchType());
+      }
+
+      // Show the compare operator between current and install version
+      if (S.InstallVer != 0)
+      {
+	 pkgCache::VerIterator const InstVer = S.InstVerIter(Cache);
+	 int Comp = 2;
+	 if (CurVer.end() == false)
+	    Comp = InstVer.CompareVer(CurVer);
+	 if (Comp < 0)
+	    fprintf(F,"> ");
+	 else if (Comp == 0)
+	    fprintf(F,"= ");
+	 else if (Comp > 0)
+	    fprintf(F,"< ");
+	 fprintf(F, "%s ", InstVer.VerStr());
+	 if (Version >= 3)
+	    fprintf(F, "%s %s ", InstVer.Arch(), InstVer.MultiArchType());
+      }
+      else
+      {
+	 if (Version <= 2)
+	    fprintf(F, "> - ");
+	 else
+	    fprintf(F, "> - - none ");
+      }
+
+      // Show the filename/operation
+      if (I->Op == Item::Install)
+      {
+	 // No errors here..
+	 if (I->File[0] != '/')
+	    fprintf(F,"**ERROR**\n");
+	 else
+	    fprintf(F,"%s\n",I->File.c_str());
+      }
+      else if (I->Op == Item::Configure)
+	 fprintf(F,"**CONFIGURE**\n");
+      else if (I->Op == Item::Remove ||
+	  I->Op == Item::Purge)
+	 fprintf(F,"**REMOVE**\n");
+
+      if (ferror(F) != 0)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+// DPkgPM::RunScriptsWithPkgs - Run scripts with package names on stdin /*{{{*/
+// ---------------------------------------------------------------------
+/* This looks for a list of scripts to run from the configuration file
+   each one is run and is fed on standard input a list of all .deb files
+   that are due to be installed. */
+bool pkgDPkgPM::RunScriptsWithPkgs(const char *Cnf)
+{
+   bool result = true;
+
+   Configuration::Item const *Opts = _config->Tree(Cnf);
+   if (Opts == 0 || Opts->Child == 0)
+      return true;
+   Opts = Opts->Child;
+
+   sighandler_t old_sigpipe = signal(SIGPIPE, SIG_IGN);
+   sighandler_t old_sigint = signal(SIGINT, SIG_IGN);
+   sighandler_t old_sigquit = signal(SIGQUIT, SIG_IGN);
+
+   unsigned int Count = 1;
+   for (; Opts != 0; Opts = Opts->Next, Count++)
+   {
+      if (Opts->Value.empty() == true)
+         continue;
+
+      if(_config->FindB("Debug::RunScripts", false) == true)
+         std::clog << "Running external script with list of all .deb file: '"
+                   << Opts->Value << "'" << std::endl;
+
+      // Determine the protocol version
+      string OptSec = Opts->Value;
+      string::size_type Pos;
+      if ((Pos = OptSec.find(' ')) == string::npos || Pos == 0)
+	 Pos = OptSec.length();
+      OptSec = "DPkg::Tools::Options::" + string(Opts->Value.c_str(),Pos);
+
+      unsigned int Version = _config->FindI(OptSec+"::Version",1);
+      unsigned int InfoFD = _config->FindI(OptSec + "::InfoFD", STDIN_FILENO);
+
+      // Create the pipes
+      std::set<int> KeepFDs;
+      MergeKeepFdsFromConfiguration(KeepFDs);
+      int Pipes[2];
+      if (pipe(Pipes) != 0) {
+         result = _error->Errno("pipe","Failed to create IPC pipe to subprocess");
+         break;
+      }
+      if (InfoFD != (unsigned)Pipes[0])
+	 SetCloseExec(Pipes[0],true);
+      else
+         KeepFDs.insert(Pipes[0]);
+
+
+      SetCloseExec(Pipes[1],true);
+
+      // Purified Fork for running the script
+      pid_t Process = ExecFork(KeepFDs);
+      if (Process == 0)
+      {
+	 // Setup the FDs
+	 dup2(Pipes[0], InfoFD);
+	 SetCloseExec(STDOUT_FILENO,false);
+	 SetCloseExec(STDIN_FILENO,false);
+	 SetCloseExec(STDERR_FILENO,false);
+
+	 string hookfd;
+	 strprintf(hookfd, "%d", InfoFD);
+	 setenv("APT_HOOK_INFO_FD", hookfd.c_str(), 1);
+
+	 if (_system != nullptr && _system->IsLocked() == true && stringcasecmp(Cnf, "DPkg::Pre-Install-Pkgs") == 0)
+	    setenv("DPKG_FRONTEND_LOCKED", "true", 1);
+
+	 debSystem::DpkgChrootDirectory();
+	 const char *Args[4];
+	 Args[0] = "/bin/sh";
+	 Args[1] = "-c";
+	 Args[2] = Opts->Value.c_str();
+	 Args[3] = 0;
+	 execv(Args[0],(char **)Args);
+	 _exit(100);
+      }
+      close(Pipes[0]);
+      FILE *F = fdopen(Pipes[1],"w");
+      if (F == 0) {
+         result = _error->Errno("fdopen","Failed to open new FD");
+         break;
+      }
+
+      // Feed it the filenames.
+      if (Version <= 1)
+      {
+	 for (vector<Item>::iterator I = List.begin(); I != List.end(); ++I)
+	 {
+	    // Only deal with packages to be installed from .deb
+	    if (I->Op != Item::Install)
+	       continue;
+
+	    // No errors here..
+	    if (I->File[0] != '/')
+	       continue;
+
+	    /* Feed the filename of each package that is pending install
+	       into the pipe. */
+	    fprintf(F,"%s\n",I->File.c_str());
+	    if (ferror(F) != 0)
+	       break;
+	 }
+      }
+      else
+	 SendPkgsInfo(F, Version);
+
+      fclose(F);
+
+      // Clean up the sub process
+      if (ExecWait(Process,Opts->Value.c_str()) == false) {
+	 result = _error->Error("Failure running script %s",Opts->Value.c_str());
+         break;
+      }
+   }
+   signal(SIGINT, old_sigint);
+   signal(SIGPIPE, old_sigpipe);
+   signal(SIGQUIT, old_sigquit);
+
+   return result;
+}
+									/*}}}*/
+// DPkgPM::DoStdin - Read stdin and pass to master pty			/*{{{*/
+// ---------------------------------------------------------------------
+/*
+*/
+void pkgDPkgPM::DoStdin(int master)
+{
+   unsigned char input_buf[256] = {0,}; 
+   ssize_t len = read(STDIN_FILENO, input_buf, sizeof(input_buf));
+   if (len)
+      FileFd::Write(master, input_buf, len);
+   else
+      d->stdin_is_dev_null = true;
+}
+									/*}}}*/
+// DPkgPM::DoTerminalPty - Read the terminal pty and write log		/*{{{*/
+// ---------------------------------------------------------------------
+/*
+ * read the terminal pty and write log
+ */
+void pkgDPkgPM::DoTerminalPty(int master)
+{
+   unsigned char term_buf[1024] = {0,0, };
+
+   ssize_t len=read(master, term_buf, sizeof(term_buf));
+   if(len == -1 && errno == EIO)
+   {
+      // this happens when the child is about to exit, we
+      // give it time to actually exit, otherwise we run
+      // into a race so we sleep for half a second.
+      struct timespec sleepfor = { 0, 500000000 };
+      nanosleep(&sleepfor, NULL);
+      return;
+   }
+   if(len <= 0)
+      return;
+   FileFd::Write(1, term_buf, len);
+   if(d->term_out)
+      fwrite(term_buf, len, sizeof(char), d->term_out);
+}
+									/*}}}*/
+// DPkgPM::ProcessDpkgStatusBuf						/*{{{*/
+void pkgDPkgPM::ProcessDpkgStatusLine(char *line)
+{
+   bool const Debug = _config->FindB("Debug::pkgDPkgProgressReporting",false);
+   if (Debug == true)
+      std::clog << "got from dpkg '" << line << "'" << std::endl;
+
+   /* dpkg sends strings like this:
+      'status:   <pkg>: <pkg  qstate>'
+      'status:   <pkg>:<arch>: <pkg  qstate>'
+
+      'processing: {install,upgrade,configure,remove,purge,disappear,trigproc}: pkg'
+      'processing: {install,upgrade,configure,remove,purge,disappear,trigproc}: trigger'
+   */
+
+   // we need to split on ": " (note the appended space) as the ':' is
+   // part of the pkgname:arch information that dpkg sends
+   //
+   // A dpkg error message may contain additional ":" (like
+   //  "failed in buffer_write(fd) (10, ret=-1): backend dpkg-deb ..."
+   // so we need to ensure to not split too much
+   std::vector<std::string> list = StringSplit(line, ": ", 4);
+   if(list.size() < 3)
+   {
+      if (Debug == true)
+	 std::clog << "ignoring line: not enough ':'" << std::endl;
+      return;
+   }
+
+   // build the (prefix, pkgname, action) tuple, position of this
+   // is different for "processing" or "status" messages
+   std::string prefix = APT::String::Strip(list[0]);
+   std::string pkgname;
+   std::string action;
+
+   // "processing" has the form "processing: action: pkg or trigger"
+   // with action = ["install", "upgrade", "configure", "remove", "purge",
+   //                "disappear", "trigproc"]
+   if (prefix == "processing")
+   {
+      pkgname = APT::String::Strip(list[2]);
+      action = APT::String::Strip(list[1]);
+   }
+   // "status" has the form: "status: pkg: state"
+   // with state in ["half-installed", "unpacked", "half-configured",
+   //                "installed", "config-files", "not-installed"]
+   else if (prefix == "status")
+   {
+      pkgname = APT::String::Strip(list[1]);
+      action = APT::String::Strip(list[2]);
+
+      /* handle the special cases first:
+
+	 errors look like this:
+	 'status: /var/cache/apt/archives/krecipes_0.8.1-0ubuntu1_i386.deb : error : trying to overwrite `/usr/share/doc/kde/HTML/en/krecipes/krectip.png', which is also in package krecipes-data
+	 and conffile-prompt like this
+	 'status:/etc/compiz.conf/compiz.conf :  conffile-prompt: 'current-conffile' 'new-conffile' useredited distedited
+	 */
+      if(action == "error")
+      {
+         d->progress->Error(pkgname, PackagesDone, PackagesTotal, list[3]);
+         ++pkgFailures;
+         WriteApportReport(pkgname.c_str(), list[3].c_str());
+         return;
+      }
+      else if(action == "conffile-prompt")
+      {
+         d->progress->ConffilePrompt(pkgname, PackagesDone, PackagesTotal, list[3]);
+         return;
+      }
+   } else {
+      if (Debug == true)
+	 std::clog << "unknown prefix '" << prefix << "'" << std::endl;
+      return;
+   }
+
+   // At this point we have a pkgname, but it might not be arch-qualified !
+   if (pkgname.find(":") == std::string::npos)
+   {
+      pkgCache::GrpIterator const Grp = Cache.FindGrp(pkgname);
+      if (unlikely(Grp.end()== true))
+      {
+	 if (Debug == true)
+	    std::clog << "unable to figure out which package is dpkg referring to with '" << pkgname << "'! (0)" << std::endl;
+	 return;
+      }
+      /* No arch means that dpkg believes there can only be one package
+         this can refer to so lets see what could be candidates here: */
+      std::vector<pkgCache::PkgIterator> candset;
+      for (auto P = Grp.PackageList(); P.end() != true; P = Grp.NextPkg(P))
+      {
+	 if (PackageOps.find(P.FullName()) != PackageOps.end())
+	    candset.push_back(P);
+	 // packages can disappear without them having any interaction itself
+	 // so we have to consider these as candidates, too
+	 else if (P->CurrentVer != 0 && action == "disappear")
+	    candset.push_back(P);
+      }
+      if (unlikely(candset.empty()))
+      {
+	 if (Debug == true)
+	    std::clog << "unable to figure out which package is dpkg referring to with '" << pkgname << "'! (1)" << std::endl;
+	 return;
+      }
+      else if (candset.size() == 1) // we are lucky
+	 pkgname = candset.cbegin()->FullName();
+      else
+      {
+	 /* here be dragons^Wassumptions about dpkg:
+	    - an M-A:same version is always arch-qualified
+	    - a package from a foreign arch is (in newer versions) */
+	 size_t installedInstances = 0, wannabeInstances = 0;
+	 for (auto const &P: candset)
+	 {
+	    if (P->CurrentVer != 0)
+	    {
+	       ++installedInstances;
+	       if (Cache[P].Delete() == false)
+		  ++wannabeInstances;
+	    }
+	    else if (Cache[P].Install())
+	       ++wannabeInstances;
+	 }
+	 // the package becomes M-A:same, so we are still talking about current
+	 if (installedInstances == 1 && wannabeInstances >= 2)
+	 {
+	    for (auto const &P: candset)
+	    {
+	       if (P->CurrentVer == 0)
+		  continue;
+	       pkgname = P.FullName();
+	       break;
+	    }
+	 }
+	 // the package was M-A:same, it isn't now, so we can only talk about that
+	 else if (installedInstances >= 2 && wannabeInstances == 1)
+	 {
+	    for (auto const &P: candset)
+	    {
+	       auto const IV = Cache[P].InstVerIter(Cache);
+	       if (IV.end())
+		  continue;
+	       pkgname = P.FullName();
+	       break;
+	    }
+	 }
+	 // that is a crossgrade
+	 else if (installedInstances == 1 && wannabeInstances == 1 && candset.size() == 2)
+	 {
+	    auto const PkgHasCurrentVersion = [](pkgCache::PkgIterator const &P) { return P->CurrentVer != 0; };
+	    auto const P = std::find_if(candset.begin(), candset.end(), PkgHasCurrentVersion);
+	    if (unlikely(P == candset.end()))
+	    {
+	       if (Debug == true)
+		  std::clog << "situation for '" << pkgname << "' looked like a crossgrade, but no current version?!" << std::endl;
+	       return;
+	    }
+	    auto fullname = P->FullName();
+	    if (PackageOps[fullname].size() != PackageOpsDone[fullname])
+	       pkgname = std::move(fullname);
+	    else
+	    {
+	       auto const pkgi = std::find_if_not(candset.begin(), candset.end(), PkgHasCurrentVersion);
+	       if (unlikely(pkgi == candset.end()))
+	       {
+		  if (Debug == true)
+		     std::clog << "situation for '" << pkgname << "' looked like a crossgrade, but all are installed?!" << std::endl;
+		  return;
+	       }
+	       pkgname = pkgi->FullName();
+	    }
+	 }
+	 // we are desperate: so "just" take the native one, but that might change mid-air,
+	 // so we have to ask dpkg what it believes native is at the moment… all the time
+	 else
+	 {
+	    std::vector<std::string> sArgs = debSystem::GetDpkgBaseCommand();
+	    sArgs.push_back("--print-architecture");
+	    int outputFd = -1;
+	    pid_t const dpkgNativeArch = debSystem::ExecDpkg(sArgs, nullptr, &outputFd, true);
+	    if (unlikely(dpkgNativeArch == -1))
+	    {
+	       if (Debug == true)
+		  std::clog << "calling dpkg failed to ask it for its current native architecture to expand '" << pkgname << "'!" << std::endl;
+	       return;
+	    }
+	    FILE *dpkg = fdopen(outputFd, "r");
+	    if(dpkg != NULL)
+	    {
+	       char* buf = NULL;
+	       size_t bufsize = 0;
+	       if (getline(&buf, &bufsize, dpkg) != -1)
+		  pkgname += ':' + bufsize;
+	       free(buf);
+	       fclose(dpkg);
+	    }
+	    ExecWait(dpkgNativeArch, "dpkg --print-architecture", true);
+	    if (pkgname.find(':') != std::string::npos)
+	    {
+	       if (Debug == true)
+		  std::clog << "unable to figure out which package is dpkg referring to with '" << pkgname << "'! (2)" << std::endl;
+	       return;
+	    }
+	 }
+      }
+   }
+
+   std::string arch = "";
+   if (pkgname.find(":") != string::npos)
+      arch = StringSplit(pkgname, ":")[1];
+   std::string i18n_pkgname = pkgname;
+   if (arch.size() != 0)
+      strprintf(i18n_pkgname, "%s (%s)", StringSplit(pkgname, ":")[0].c_str(), arch.c_str());
+
+   // 'processing' from dpkg looks like
+   // 'processing: action: pkg'
+   if(prefix == "processing")
+   {
+      auto const iter = std::find_if(PackageProcessingOpsBegin, PackageProcessingOpsEnd, MatchProcessingOp(action.c_str()));
+      if(iter == PackageProcessingOpsEnd)
+      {
+	 if (Debug == true)
+	    std::clog << "ignoring unknown action: " << action << std::endl;
+	 return;
+      }
+      std::string msg;
+      strprintf(msg, _(iter->second), i18n_pkgname.c_str());
+      d->progress->StatusChanged(pkgname, PackagesDone, PackagesTotal, msg);
+
+      // FIXME: this needs a muliarch testcase
+      // FIXME2: is "pkgname" here reliable with dpkg only sending us
+      //         short pkgnames?
+      if (action == "disappear")
+	 handleDisappearAction(pkgname);
+      else if (action == "upgrade")
+	 handleCrossUpgradeAction(pkgname);
+      return;
+   }
+
+   if (prefix == "status")
+   {
+      std::vector<struct DpkgState> &states = PackageOps[pkgname];
+      if(PackageOpsDone[pkgname] < states.size())
+      {
+	 char const * next_action = states[PackageOpsDone[pkgname]].state;
+	 if (next_action)
+	 {
+	    /*
+	    if (action == "half-installed" && strcmp("half-configured", next_action) == 0 &&
+		  PackageOpsDone[pkg] + 2 < states.size() && action == states[PackageOpsDone[pkg] + 2].state)
+	    {
+	       if (Debug == true)
+		  std::clog << "(parsed from dpkg) pkg: " << short_pkgname << " action: " << action
+		     << " pending trigger defused by unpack" << std::endl;
+	       // unpacking a package defuses the pending trigger
+	       PackageOpsDone[pkg] += 2;
+	       PackagesDone += 2;
+	       next_action = states[PackageOpsDone[pkg]].state;
+	    }
+	    */
+	    if (Debug == true)
+	       std::clog << "(parsed from dpkg) pkg: " << pkgname
+		  << " action: " << action << " (expected: '" << next_action << "' "
+		  << PackageOpsDone[pkgname] << " of " << states.size() << ")" << endl;
+
+	    // check if the package moved to the next dpkg state
+	    if(action == next_action)
+	    {
+	       // only read the translation if there is actually a next action
+	       char const * const translation = _(states[PackageOpsDone[pkgname]].str);
+
+	       // we moved from one dpkg state to a new one, report that
+	       ++PackageOpsDone[pkgname];
+	       ++PackagesDone;
+
+	       std::string msg;
+	       strprintf(msg, translation, i18n_pkgname.c_str());
+	       d->progress->StatusChanged(pkgname, PackagesDone, PackagesTotal, msg);
+	    }
+	 }
+      }
+      else if (action == "triggers-pending")
+      {
+	 if (Debug == true)
+	    std::clog << "(parsed from dpkg) pkg: " << pkgname
+	       << " action: " << action << " (prefix 2 to "
+	       << PackageOpsDone[pkgname] << " of " << states.size() << ")" << endl;
+
+	 states.insert(states.begin(), {"installed", N_("Installed %s")});
+	 states.insert(states.begin(), {"half-configured", N_("Configuring %s")});
+	 PackagesTotal += 2;
+      }
+   }
+}
+									/*}}}*/
+// DPkgPM::handleDisappearAction					/*{{{*/
+void pkgDPkgPM::handleDisappearAction(string const &pkgname)
+{
+   pkgCache::PkgIterator Pkg = Cache.FindPkg(pkgname);
+   if (unlikely(Pkg.end() == true))
+      return;
+
+   // a disappeared package has no further actions
+   auto const ROps = PackageOps[Pkg.FullName()].size();
+   auto && ROpsDone = PackageOpsDone[Pkg.FullName()];
+   PackagesDone += ROps - ROpsDone;
+   ROpsDone = ROps;
+
+   // record the package name for display and stuff later
+   disappearedPkgs.insert(Pkg.FullName(true));
+
+   // the disappeared package was auto-installed - nothing to do
+   if ((Cache[Pkg].Flags & pkgCache::Flag::Auto) == pkgCache::Flag::Auto)
+      return;
+   pkgCache::VerIterator PkgVer = Cache[Pkg].InstVerIter(Cache);
+   if (unlikely(PkgVer.end() == true))
+      return;
+   /* search in the list of dependencies for (Pre)Depends,
+      check if this dependency has a Replaces on our package
+      and if so transfer the manual installed flag to it */
+   for (pkgCache::DepIterator Dep = PkgVer.DependsList(); Dep.end() != true; ++Dep)
+   {
+      if (Dep->Type != pkgCache::Dep::Depends &&
+	  Dep->Type != pkgCache::Dep::PreDepends)
+	 continue;
+      pkgCache::PkgIterator Tar = Dep.TargetPkg();
+      if (unlikely(Tar.end() == true))
+	 continue;
+      // the package is already marked as manual
+      if ((Cache[Tar].Flags & pkgCache::Flag::Auto) != pkgCache::Flag::Auto)
+	 continue;
+      pkgCache::VerIterator TarVer =  Cache[Tar].InstVerIter(Cache);
+      if (TarVer.end() == true)
+	 continue;
+      for (pkgCache::DepIterator Rep = TarVer.DependsList(); Rep.end() != true; ++Rep)
+      {
+	 if (Rep->Type != pkgCache::Dep::Replaces)
+	    continue;
+	 if (Pkg != Rep.TargetPkg())
+	    continue;
+	 // okay, they are strongly connected - transfer manual-bit
+	 if (Debug == true)
+	    std::clog << "transfer manual-bit from disappeared »" << pkgname << "« to »" << Tar.FullName() << "«" << std::endl;
+	 Cache[Tar].Flags &= ~Flag::Auto;
+	 break;
+      }
+   }
+}
+									/*}}}*/
+void pkgDPkgPM::handleCrossUpgradeAction(string const &pkgname)		/*{{{*/
+{
+   // in a crossgrade what looked like a remove first is really an unpack over it
+   auto const Pkg = Cache.FindPkg(pkgname);
+   if (likely(Pkg.end() == false) && Cache[Pkg].Delete())
+   {
+      auto const Grp = Pkg.Group();
+      if (likely(Grp.end() == false))
+      {
+	 for (auto P = Grp.PackageList(); P.end() != true; P = Grp.NextPkg(P))
+	    if(Cache[P].Install())
+	    {
+	       auto && Ops = PackageOps[P.FullName()];
+	       auto const unpackOp = std::find_if(Ops.cbegin(), Ops.cend(), [](DpkgState const &s) { return strcmp(s.state, "unpacked") == 0; });
+	       if (unpackOp != Ops.cend())
+	       {
+		  // skip ahead in the crossgraded packages
+		  auto const skipped = std::distance(Ops.cbegin(), unpackOp);
+		  PackagesDone += skipped;
+		  PackageOpsDone[P.FullName()] += skipped;
+		  // finish the crossremoved package
+		  auto const ROps = PackageOps[Pkg.FullName()].size();
+		  auto && ROpsDone = PackageOpsDone[Pkg.FullName()];
+		  PackagesDone += ROps - ROpsDone;
+		  ROpsDone = ROps;
+		  break;
+	       }
+	    }
+      }
+   }
+}
+									/*}}}*/
+// DPkgPM::DoDpkgStatusFd						/*{{{*/
+void pkgDPkgPM::DoDpkgStatusFd(int statusfd)
+{
+   auto const remainingBuffer = (sizeof(d->dpkgbuf) / sizeof(d->dpkgbuf[0])) - d->dpkgbuf_pos;
+   if (likely(remainingBuffer > 0) && d->status_fd_reached_end_of_file == false)
+   {
+      auto const len = read(statusfd, &d->dpkgbuf[d->dpkgbuf_pos], remainingBuffer);
+      if (len < 0)
+	 return;
+      else if (len == 0 && d->dpkgbuf_pos == 0)
+      {
+	 d->status_fd_reached_end_of_file = true;
+	 return;
+      }
+      d->dpkgbuf_pos += (len / sizeof(d->dpkgbuf[0]));
+   }
+
+   // process line by line from the buffer
+   char *p = d->dpkgbuf, *q = nullptr;
+   while((q=(char*)memchr(p, '\n', (d->dpkgbuf + d->dpkgbuf_pos) - p)) != nullptr)
+   {
+      *q = '\0';
+      ProcessDpkgStatusLine(p);
+      p = q + 1; // continue with next line
+   }
+
+   // check if we stripped the buffer clean
+   if (p > (d->dpkgbuf + d->dpkgbuf_pos))
+   {
+      d->dpkgbuf_pos = 0;
+      return;
+   }
+
+   // otherwise move the unprocessed tail to the start and update pos
+   memmove(d->dpkgbuf, p, (p - d->dpkgbuf));
+   d->dpkgbuf_pos = (d->dpkgbuf + d->dpkgbuf_pos) - p;
+}
+									/*}}}*/
+// DPkgPM::WriteHistoryTag						/*{{{*/
+void pkgDPkgPM::WriteHistoryTag(string const &tag, string value)
+{
+   size_t const length = value.length();
+   if (length == 0)
+      return;
+   // poor mans rstrip(", ")
+   if (value[length-2] == ',' && value[length-1] == ' ')
+      value.erase(length - 2, 2);
+   fprintf(d->history_out, "%s: %s\n", tag.c_str(), value.c_str());
+}									/*}}}*/
+// DPkgPM::OpenLog							/*{{{*/
+bool pkgDPkgPM::OpenLog()
+{
+   string const logfile_name =  _config->FindFile("Dir::Log::Terminal", "/dev/null");
+   string logdir = flNotFile(logfile_name);
+   if(CreateAPTDirectoryIfNeeded(logdir, logdir) == false)
+      // FIXME: use a better string after freeze
+      return _error->Error(_("Directory '%s' missing"), logdir.c_str());
+
+   // get current time
+   char timestr[200];
+   time_t const t = time(NULL);
+   struct tm tm_buf;
+   struct tm const * const tmp = localtime_r(&t, &tm_buf);
+   strftime(timestr, sizeof(timestr), "%F  %T", tmp);
+
+   // open terminal log
+   if (logfile_name != "/dev/null")
+   {
+      d->term_out = fopen(logfile_name.c_str(),"a");
+      if (d->term_out == NULL)
+	 return _error->WarningE("OpenLog", _("Could not open file '%s'"), logfile_name.c_str());
+      setvbuf(d->term_out, NULL, _IONBF, 0);
+      SetCloseExec(fileno(d->term_out), true);
+      if (getuid() == 0) // if we aren't root, we can't chown a file, so don't try it
+      {
+	 struct passwd *pw = getpwnam("root");
+	 struct group *gr = getgrnam("adm");
+	 if (pw != NULL && gr != NULL && chown(logfile_name.c_str(), pw->pw_uid, gr->gr_gid) != 0)
+	    _error->WarningE("OpenLog", "chown to root:adm of file %s failed", logfile_name.c_str());
+      }
+      if (chmod(logfile_name.c_str(), 0640) != 0)
+	 _error->WarningE("OpenLog", "chmod 0640 of file %s failed", logfile_name.c_str());
+      fprintf(d->term_out, "\nLog started: %s\n", timestr);
+   }
+
+   // write your history
+   string const history_name = _config->FindFile("Dir::Log::History", "/dev/null");
+   string logdir2 = flNotFile(logfile_name);
+   if(logdir != logdir2 && CreateAPTDirectoryIfNeeded(logdir2, logdir2) == false)
+      return _error->Error(_("Directory '%s' missing"), logdir.c_str());
+   if (history_name != "/dev/null")
+   {
+      d->history_out = fopen(history_name.c_str(),"a");
+      if (d->history_out == NULL)
+	 return _error->WarningE("OpenLog", _("Could not open file '%s'"), history_name.c_str());
+      SetCloseExec(fileno(d->history_out), true);
+      chmod(history_name.c_str(), 0644);
+      fprintf(d->history_out, "\nStart-Date: %s\n", timestr);
+      string remove, purge, install, reinstall, upgrade, downgrade;
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      {
+	 enum { CANDIDATE, CANDIDATE_AUTO, CURRENT_CANDIDATE, CURRENT } infostring;
+	 string *line = NULL;
+	 #define HISTORYINFO(X, Y) { line = &X; infostring = Y; }
+	 if (Cache[I].NewInstall() == true)
+	    HISTORYINFO(install, CANDIDATE_AUTO)
+	 else if (Cache[I].ReInstall() == true)
+	    HISTORYINFO(reinstall, CANDIDATE)
+	 else if (Cache[I].Upgrade() == true)
+	    HISTORYINFO(upgrade, CURRENT_CANDIDATE)
+	 else if (Cache[I].Downgrade() == true)
+	    HISTORYINFO(downgrade, CURRENT_CANDIDATE)
+	 else if (Cache[I].Delete() == true)
+	    HISTORYINFO((Cache[I].Purge() ? purge : remove), CURRENT)
+	 else
+	    continue;
+	 #undef HISTORYINFO
+	 line->append(I.FullName(false)).append(" (");
+	 switch (infostring) {
+	 case CANDIDATE: line->append(Cache[I].CandVersion); break;
+	 case CANDIDATE_AUTO:
+	    line->append(Cache[I].CandVersion);
+	    if ((Cache[I].Flags & pkgCache::Flag::Auto) == pkgCache::Flag::Auto)
+	       line->append(", automatic");
+	    break;
+	 case CURRENT_CANDIDATE: line->append(Cache[I].CurVersion).append(", ").append(Cache[I].CandVersion); break;
+	 case CURRENT: line->append(Cache[I].CurVersion); break;
+	 }
+	 line->append("), ");
+      }
+      if (_config->Exists("Commandline::AsString") == true)
+	 WriteHistoryTag("Commandline", _config->Find("Commandline::AsString"));
+      std::string RequestingUser = AptHistoryRequestingUser();
+      if (RequestingUser != "")
+         WriteHistoryTag("Requested-By", RequestingUser);
+      WriteHistoryTag("Install", install);
+      WriteHistoryTag("Reinstall", reinstall);
+      WriteHistoryTag("Upgrade", upgrade);
+      WriteHistoryTag("Downgrade",downgrade);
+      WriteHistoryTag("Remove",remove);
+      WriteHistoryTag("Purge",purge);
+      fflush(d->history_out);
+   }
+
+   return true;
+}
+									/*}}}*/
+// DPkg::CloseLog							/*{{{*/
+bool pkgDPkgPM::CloseLog()
+{
+   char timestr[200];
+   time_t t = time(NULL);
+   struct tm tm_buf;
+   struct tm *tmp = localtime_r(&t, &tm_buf);
+   strftime(timestr, sizeof(timestr), "%F  %T", tmp);
+
+   if(d->term_out)
+   {
+      fprintf(d->term_out, "Log ended: ");
+      fprintf(d->term_out, "%s", timestr);
+      fprintf(d->term_out, "\n");
+      fclose(d->term_out);
+   }
+   d->term_out = NULL;
+
+   if(d->history_out)
+   {
+      if (disappearedPkgs.empty() == false)
+      {
+	 string disappear;
+	 for (std::set<std::string>::const_iterator d = disappearedPkgs.begin();
+	      d != disappearedPkgs.end(); ++d)
+	 {
+	    pkgCache::PkgIterator P = Cache.FindPkg(*d);
+	    disappear.append(*d);
+	    if (P.end() == true)
+	       disappear.append(", ");
+	    else
+	       disappear.append(" (").append(Cache[P].CurVersion).append("), ");
+	 }
+	 WriteHistoryTag("Disappeared", disappear);
+      }
+      if (d->dpkg_error.empty() == false)
+	 fprintf(d->history_out, "Error: %s\n", d->dpkg_error.c_str());
+      fprintf(d->history_out, "End-Date: %s\n", timestr);
+      fclose(d->history_out);
+   }
+   d->history_out = NULL;
+
+   return true;
+}
+									/*}}}*/
+
+// DPkgPM::BuildPackagesProgressMap					/*{{{*/
+void pkgDPkgPM::BuildPackagesProgressMap()
+{
+   // map the dpkg states to the operations that are performed
+   // (this is sorted in the same way as Item::Ops)
+   static const std::array<std::array<DpkgState, 2>, 4> DpkgStatesOpMap = {{
+      // Install operation
+      {{
+	 {"half-installed", N_("Unpacking %s")},
+	 {"unpacked", N_("Installing %s") },
+      }},
+      // Configure operation
+      {{
+	 {"half-configured", N_("Configuring %s") },
+	 { "installed", N_("Installed %s")},
+      }},
+      // Remove operation
+      {{
+	 {"half-configured", N_("Removing %s")},
+	 {"half-installed", N_("Removing %s")},
+      }},
+      // Purge operation
+      {{
+	 {"config-files", N_("Completely removing %s")},
+	 {"not-installed", N_("Completely removed %s")},
+      }},
+   }};
+   static_assert(Item::Purge == 3, "Enum item has unexpected index for mapping array");
+
+   // init the PackageOps map, go over the list of packages that
+   // that will be [installed|configured|removed|purged] and add
+   // them to the PackageOps map (the dpkg states it goes through)
+   // and the PackageOpsTranslations (human readable strings)
+   for (auto &&I : List)
+   {
+      if(I.Pkg.end() == true)
+	 continue;
+
+      string const name = I.Pkg.FullName();
+      PackageOpsDone[name] = 0;
+      auto AddToPackageOps = [&](decltype(I.Op) const Op) {
+	 auto const DpkgOps = DpkgStatesOpMap[Op];
+	 std::copy(DpkgOps.begin(), DpkgOps.end(), std::back_inserter(PackageOps[name]));
+	 PackagesTotal += DpkgOps.size();
+      };
+      // purging a package which is installed first passes through remove states
+      if (I.Op == Item::Purge && I.Pkg->CurrentVer != 0)
+	 AddToPackageOps(Item::Remove);
+      AddToPackageOps(I.Op);
+
+      if ((I.Op == Item::Remove || I.Op == Item::Purge) && I.Pkg->CurrentVer != 0)
+      {
+	 if (I.Pkg->CurrentState == pkgCache::State::UnPacked ||
+	       I.Pkg->CurrentState == pkgCache::State::HalfInstalled)
+	 {
+	    if (likely(strcmp(PackageOps[name][0].state, "half-configured") == 0))
+	    {
+	       ++PackageOpsDone[name];
+	       --PackagesTotal;
+	    }
+	 }
+      }
+   }
+   /* one extra: We don't want the progress bar to reach 100%, especially not
+      if we call dpkg --configure --pending and process a bunch of triggers
+      while showing 100%. Also, spindown takes a while, so never reaching 100%
+      is way more correct than reaching 100% while still doing stuff even if
+      doing it this way is slightly bending the rules */
+   ++PackagesTotal;
+}
+                                                                        /*}}}*/
+void pkgDPkgPM::StartPtyMagic()						/*{{{*/
+{
+   if (_config->FindB("Dpkg::Use-Pty", true) == false)
+   {
+      d->master = -1;
+      if (d->slave != NULL)
+	 free(d->slave);
+      d->slave = NULL;
+      return;
+   }
+
+   if (isatty(STDIN_FILENO) == 0)
+      d->direct_stdin = true;
+
+   _error->PushToStack();
+
+   d->master = posix_openpt(O_RDWR | O_NOCTTY);
+   if (d->master == -1)
+      _error->Errno("posix_openpt", _("Can not write log (%s)"), _("Is /dev/pts mounted?"));
+   else if (unlockpt(d->master) == -1)
+      _error->Errno("unlockpt", "Unlocking the slave of master fd %d failed!", d->master);
+   else
+   {
+#ifdef HAVE_PTSNAME_R
+      char slave_name[64];	// 64 is used by bionic
+      if (ptsname_r(d->master, slave_name, sizeof(slave_name)) != 0)
+#else
+      char const * const slave_name = ptsname(d->master);
+      if (slave_name == NULL)
+#endif
+	 _error->Errno("ptsname", "Getting name for slave of master fd %d failed!", d->master);
+      else
+      {
+	 d->slave = strdup(slave_name);
+	 if (d->slave == NULL)
+	    _error->Errno("strdup", "Copying name %s for slave of master fd %d failed!", slave_name, d->master);
+	 else if (grantpt(d->master) == -1)
+	    _error->Errno("grantpt", "Granting access to slave %s based on master fd %d failed!", slave_name, d->master);
+	 else if (tcgetattr(STDIN_FILENO, &d->tt) == 0)
+	 {
+	    d->tt_is_valid = true;
+	    struct termios raw_tt;
+	    // copy window size of stdout if its a 'good' terminal
+	    if (tcgetattr(STDOUT_FILENO, &raw_tt) == 0)
+	    {
+	       struct winsize win;
+	       if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) < 0)
+		  _error->Errno("ioctl", "Getting TIOCGWINSZ from stdout failed!");
+	       if (ioctl(d->master, TIOCSWINSZ, &win) < 0)
+		  _error->Errno("ioctl", "Setting TIOCSWINSZ for master fd %d failed!", d->master);
+	    }
+	    if (tcsetattr(d->master, TCSANOW, &d->tt) == -1)
+	       _error->Errno("tcsetattr", "Setting in Start via TCSANOW for master fd %d failed!", d->master);
+
+	    raw_tt = d->tt;
+	    cfmakeraw(&raw_tt);
+	    raw_tt.c_lflag &= ~ECHO;
+	    raw_tt.c_lflag |= ISIG;
+	    // block SIGTTOU during tcsetattr to prevent a hang if
+	    // the process is a member of the background process group
+	    // http://www.opengroup.org/onlinepubs/000095399/functions/tcsetattr.html
+	    sigemptyset(&d->sigmask);
+	    sigaddset(&d->sigmask, SIGTTOU);
+	    sigprocmask(SIG_BLOCK,&d->sigmask, &d->original_sigmask);
+	    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw_tt) == -1)
+	       _error->Errno("tcsetattr", "Setting in Start via TCSAFLUSH for stdin failed!");
+	    sigprocmask(SIG_SETMASK, &d->original_sigmask, NULL);
+
+	 }
+	 if (d->slave != NULL)
+	 {
+	    /* on linux, closing (and later reopening) all references to the slave
+	       makes the slave a death end, so we open it here to have one open all
+	       the time. We could use this fd in SetupSlavePtyMagic() for linux, but
+	       on kfreebsd we get an incorrect ("step like") output then while it has
+	       no problem with closing all references… so to avoid platform specific
+	       code here we combine both and be happy once more */
+	    d->protect_slave_from_dying = open(d->slave, O_RDWR | O_CLOEXEC | O_NOCTTY);
+	 }
+      }
+   }
+
+   if (_error->PendingError() == true)
+   {
+      if (d->master != -1)
+      {
+	 close(d->master);
+	 d->master = -1;
+      }
+      if (d->slave != NULL)
+      {
+	 free(d->slave);
+	 d->slave = NULL;
+      }
+      _error->DumpErrors(std::cerr, GlobalError::DEBUG, false);
+   }
+   _error->RevertToStack();
+}
+									/*}}}*/
+void pkgDPkgPM::SetupSlavePtyMagic()					/*{{{*/
+{
+   if(d->master == -1 || d->slave == NULL)
+      return;
+
+   if (close(d->master) == -1)
+      _error->FatalE("close", "Closing master %d in child failed!", d->master);
+   d->master = -1;
+   if (setsid() == -1)
+      _error->FatalE("setsid", "Starting a new session for child failed!");
+
+   int const slaveFd = open(d->slave, O_RDWR | O_NOCTTY);
+   if (slaveFd == -1)
+      _error->FatalE("open", _("Can not write log (%s)"), _("Is /dev/pts mounted?"));
+   else if (ioctl(slaveFd, TIOCSCTTY, 0) < 0)
+      _error->FatalE("ioctl", "Setting TIOCSCTTY for slave fd %d failed!", slaveFd);
+   else
+   {
+      unsigned short i = 0;
+      if (d->direct_stdin == true)
+	 ++i;
+      for (; i < 3; ++i)
+	 if (dup2(slaveFd, i) == -1)
+	    _error->FatalE("dup2", "Dupping %d to %d in child failed!", slaveFd, i);
+
+      if (d->tt_is_valid == true && tcsetattr(STDIN_FILENO, TCSANOW, &d->tt) < 0)
+	 _error->FatalE("tcsetattr", "Setting in Setup via TCSANOW for slave fd %d failed!", slaveFd);
+   }
+
+   if (slaveFd != -1)
+      close(slaveFd);
+}
+									/*}}}*/
+void pkgDPkgPM::StopPtyMagic()						/*{{{*/
+{
+   if (d->slave != NULL)
+      free(d->slave);
+   d->slave = NULL;
+   if (d->protect_slave_from_dying != -1)
+   {
+      close(d->protect_slave_from_dying);
+      d->protect_slave_from_dying = -1;
+   }
+   if(d->master >= 0)
+   {
+      if (d->tt_is_valid == true && tcsetattr(STDIN_FILENO, TCSAFLUSH, &d->tt) == -1)
+	 _error->FatalE("tcsetattr", "Setting in Stop via TCSAFLUSH for stdin failed!");
+      close(d->master);
+      d->master = -1;
+   }
+}
+									/*}}}*/
+static void cleanUpTmpDir(char * const tmpdir)				/*{{{*/
+{
+   if (tmpdir == nullptr)
+      return;
+   DIR * const D = opendir(tmpdir);
+   if (D == nullptr)
+      _error->Errno("opendir", _("Unable to read %s"), tmpdir);
+   else
+   {
+      auto const dfd = dirfd(D);
+      for (struct dirent *Ent = readdir(D); Ent != nullptr; Ent = readdir(D))
+      {
+	 if (Ent->d_name[0] == '.')
+	    continue;
+#ifdef _DIRENT_HAVE_D_TYPE
+	 if (unlikely(Ent->d_type != DT_LNK && Ent->d_type != DT_UNKNOWN))
+	    continue;
+#endif
+	 if (unlikely(unlinkat(dfd, Ent->d_name, 0) != 0))
+	    break;
+      }
+      closedir(D);
+      rmdir(tmpdir);
+   }
+   free(tmpdir);
+}
+									/*}}}*/
+
+// DPkgPM::Go - Run the sequence					/*{{{*/
+// ---------------------------------------------------------------------
+/* This globs the operations and calls dpkg
+ *
+ * If it is called with a progress object apt will report the install
+ * progress to this object. It maps the dpkg states a package goes
+ * through to human readable (and i10n-able)
+ * names and calculates a percentage for each step.
+ */
+static bool ItemIsEssential(pkgDPkgPM::Item const &I)
+{
+   static auto const cachegen = _config->Find("pkgCacheGen::Essential");
+   if (cachegen == "none" || cachegen == "native")
+      return true;
+   if (unlikely(I.Pkg.end()))
+      return true;
+   return (I.Pkg->Flags & pkgCache::Flag::Essential) != 0;
+}
+static bool ItemIsProtected(pkgDPkgPM::Item const &I)
+{
+   static auto const cachegen = _config->Find("pkgCacheGen::Protected");
+   if (cachegen == "none" || cachegen == "native")
+      return true;
+   if (unlikely(I.Pkg.end()))
+      return true;
+   return (I.Pkg->Flags & pkgCache::Flag::Important) != 0;
+}
+bool pkgDPkgPM::ExpandPendingCalls(std::vector<Item> &List, pkgDepCache &Cache)
+{
+   {
+      std::unordered_set<decltype(pkgCache::Package::ID)> alreadyRemoved;
+      for (auto && I : List)
+	 if (I.Op == Item::Remove || I.Op == Item::Purge)
+	    alreadyRemoved.insert(I.Pkg->ID);
+      std::remove_reference<decltype(List)>::type AppendList;
+      for (auto Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+	 if (Cache[Pkg].Delete() && alreadyRemoved.insert(Pkg->ID).second == true)
+	    AppendList.emplace_back(Cache[Pkg].Purge() ? Item::Purge : Item::Remove, Pkg);
+      std::move(AppendList.begin(), AppendList.end(), std::back_inserter(List));
+   }
+   {
+      std::unordered_set<decltype(pkgCache::Package::ID)> alreadyConfigured;
+      for (auto && I : List)
+	 if (I.Op == Item::Configure)
+	    alreadyConfigured.insert(I.Pkg->ID);
+      std::remove_reference<decltype(List)>::type AppendList;
+      for (auto && I : List)
+	 if (I.Op == Item::Install && alreadyConfigured.insert(I.Pkg->ID).second == true)
+	    AppendList.emplace_back(Item::Configure, I.Pkg);
+      for (auto Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+	 if (Pkg.State() == pkgCache::PkgIterator::NeedsConfigure &&
+	       Cache[Pkg].Delete() == false && alreadyConfigured.insert(Pkg->ID).second == true)
+	    AppendList.emplace_back(Item::Configure, Pkg);
+      std::move(AppendList.begin(), AppendList.end(), std::back_inserter(List));
+   }
+   return true;
+}
+class APT_HIDDEN BuildDpkgCall {
+   std::vector<char*> args;
+   std::vector<bool> to_free;
+   size_t baseArguments = 0;
+   size_t baseArgumentsLen = 0;
+   size_t len = 0;
+public:
+   void clearCallArguments() {
+      for (size_t i = baseArguments; i < args.size(); ++i)
+	 if (to_free[i])
+	    std::free(args[i]);
+      args.erase(args.begin() + baseArguments, args.end());
+      to_free.erase(to_free.begin() + baseArguments, to_free.end());
+      len = baseArgumentsLen;
+   }
+   void reserve(size_t const n) {
+      args.reserve(n);
+      to_free.reserve(n);
+   }
+   void push_back(char const * const str) {
+      args.push_back(const_cast<char*>(str));
+      to_free.push_back(false);
+      len += strlen(args.back());
+   }
+   void push_back(std::string &&str) {
+      args.push_back(strdup(str.c_str()));
+      to_free.push_back(true);
+      len += str.length();
+   }
+   auto bytes() const { return len; }
+   auto data() const { return args.data(); }
+   auto begin() const { return args.cbegin(); }
+   auto end() const { return args.cend(); }
+   auto& front() const { return args.front(); }
+   APT_NORETURN void execute(char const *const errmsg) {
+      args.push_back(nullptr);
+      execvp(args.front(), &args.front());
+      std::cerr << errmsg << std::endl;
+      _exit(100);
+   }
+   BuildDpkgCall() {
+      for (auto &&arg : debSystem::GetDpkgBaseCommand())
+	 push_back(std::move(arg));
+      baseArguments = args.size();
+      baseArgumentsLen = len;
+   }
+   BuildDpkgCall(BuildDpkgCall const &) = delete;
+   BuildDpkgCall(BuildDpkgCall &&) = delete;
+   BuildDpkgCall& operator=(BuildDpkgCall const &) = delete;
+   BuildDpkgCall& operator=(BuildDpkgCall &&) = delete;
+   ~BuildDpkgCall() {
+      baseArguments = 0;
+      clearCallArguments();
+   }
+};
+bool pkgDPkgPM::Go(APT::Progress::PackageManager *progress)
+{
+   struct Inhibitor
+   {
+      int Fd = -1;
+      Inhibitor()
+      {
+	 if (_config->FindB("DPkg::Inhibit-Shutdown", true))
+	    Fd = Inhibit("shutdown", "APT", "APT is installing or removing packages", "block");
+      }
+      ~Inhibitor()
+      {
+	 if (Fd > 0)
+	    close(Fd);
+      }
+   } inhibitor;
+
+   // explicitly remove&configure everything for hookscripts and progress building
+   // we need them only temporarily through, so keep the length and erase afterwards
+   decltype(List)::const_iterator::difference_type explicitIdx =
+      std::distance(List.cbegin(), List.cend());
+   ExpandPendingCalls(List, Cache);
+
+   /* if dpkg told us that it has already done everything to the package we wanted it to do,
+      we shouldn't ask it for "more" later. That can e.g. happen if packages without conffiles
+      are purged as they will have pass through the purge states on remove already */
+   auto const StripAlreadyDoneFrom = [&](APT::VersionVector & Pending) {
+      Pending.erase(std::remove_if(Pending.begin(), Pending.end(), [&](pkgCache::VerIterator const &Ver) {
+	    auto const PN = Ver.ParentPkg().FullName();
+	    auto const POD = PackageOpsDone.find(PN);
+	    if (POD == PackageOpsDone.end())
+	       return false;
+	    return PackageOps[PN].size() <= POD->second;
+	 }), Pending.end());
+   };
+
+   pkgPackageManager::SigINTStop = false;
+   d->progress = progress;
+
+   // try to figure out the max environment size
+   int OSArgMax = sysconf(_SC_ARG_MAX);
+   if(OSArgMax < 0)
+      OSArgMax = 32*1024;
+   OSArgMax -= EnvironmentSize() - 2*1024;
+   unsigned int const MaxArgBytes = _config->FindI("Dpkg::MaxArgBytes", OSArgMax);
+   bool const NoTriggers = _config->FindB("DPkg::NoTriggers", true);
+
+   if (RunScripts("DPkg::Pre-Invoke") == false)
+      return false;
+
+   if (RunScriptsWithPkgs("DPkg::Pre-Install-Pkgs") == false)
+      return false;
+
+   auto const noopDPkgInvocation = _config->FindB("Debug::pkgDPkgPM",false);
+   // store auto-bits as they are supposed to be after dpkg is run
+   if (noopDPkgInvocation == false)
+      Cache.writeStateFile(NULL);
+
+   bool dpkg_recursive_install = _config->FindB("dpkg::install::recursive", false);
+   if (_config->FindB("dpkg::install::recursive::force", false) == false)
+   {
+      // dpkg uses a sorted treewalk since that version which enables the workaround to work
+      auto const dpkgpkg = Cache.FindPkg("dpkg");
+      if (likely(dpkgpkg.end() == false && dpkgpkg->CurrentVer != 0))
+	 dpkg_recursive_install = Cache.VS().CmpVersion("1.18.5", dpkgpkg.CurrentVer().VerStr()) <= 0;
+   }
+   // no point in doing this dance for a handful of packages only
+   unsigned int const dpkg_recursive_install_min = _config->FindI("dpkg::install::recursive::minimum", 5);
+   // FIXME: workaround for dpkg bug, see our ./test-bug-740843-versioned-up-down-breaks test
+   bool const dpkg_recursive_install_numbered = _config->FindB("dpkg::install::recursive::numbered", true);
+
+   // for the progress
+   BuildPackagesProgressMap();
+
+   APT::StateChanges approvedStates;
+   if (_config->FindB("dpkg::selection::remove::approved", true))
+   {
+      for (auto && I : List)
+	 if (I.Op == Item::Purge)
+	    approvedStates.Purge(FindToBeRemovedVersion(I.Pkg));
+	 else if (I.Op == Item::Remove)
+	    approvedStates.Remove(FindToBeRemovedVersion(I.Pkg));
+   }
+
+   // Skip removes if we install another architecture of this package soon (crossgrade)
+   // We can't just skip them all the time as it could be an ordering requirement [of another package]
+   if ((approvedStates.Remove().empty() == false || approvedStates.Purge().empty() == false) &&
+	 _config->FindB("dpkg::remove::crossgrade::implicit", true) == true)
+   {
+      std::unordered_set<decltype(pkgCache::Package::ID)> crossgraded;
+      std::vector<std::pair<Item*, std::string>> toCrossgrade;
+      auto const PlanedEnd = std::next(List.begin(), explicitIdx);
+      for (auto I = List.begin(); I != PlanedEnd; ++I)
+      {
+	 if (I->Op != Item::Remove && I->Op != Item::Purge)
+	    continue;
+
+	 auto const Grp = I->Pkg.Group();
+	 size_t installedInstances = 0, wannabeInstances = 0;
+	 bool multiArchInstances = false;
+	 for (auto Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
+	 {
+	    if (Pkg->CurrentVer != 0)
+	    {
+	       ++installedInstances;
+	       if (Cache[Pkg].Delete() == false)
+		  ++wannabeInstances;
+	    }
+	    else if (PackageOps.find(Pkg.FullName()) != PackageOps.end())
+	       ++wannabeInstances;
+	    if (multiArchInstances == false)
+	    {
+	       auto const V = Cache[Pkg].InstVerIter(Cache);
+	       if (V.end() == false && (Pkg->CurrentVer == 0 || V != Pkg.CurrentVer()))
+		  multiArchInstances = ((V->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same);
+	    }
+	 }
+	 /* theoretically the installed check would be enough as some wannabe will
+	    be first and hence be the crossgrade we were looking for, but #844300
+	    prevents this so we keep these situations explicit removes.
+	    It is also the reason why neither of them can be a M-A:same package */
+	 if (installedInstances == 1 && wannabeInstances == 1 && multiArchInstances == false)
+	 {
+	    auto const FirstInstall = std::find_if_not(I, List.end(),
+		  [](Item const &i) { return i.Op == Item::Remove || i.Op == Item::Purge; });
+	    auto const LastInstall = std::find_if_not(FirstInstall, List.end(),
+		  [](Item const &i) { return i.Op == Item::Install; });
+	    auto const crosser = std::find_if(FirstInstall, LastInstall,
+		  [&I](Item const &i) { return i.Pkg->Group == I->Pkg->Group; });
+	    if (crosser != LastInstall)
+	    {
+	       crossgraded.insert(I->Pkg->ID);
+	       toCrossgrade.emplace_back(&(*I), crosser->Pkg.FullName());
+	    }
+	 }
+      }
+      for (auto I = PlanedEnd; I != List.end(); ++I)
+      {
+	 if (I->Op != Item::Remove && I->Op != Item::Purge)
+	    continue;
+
+	 auto const Grp = I->Pkg.Group();
+	 for (auto Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
+	 {
+	    if (Pkg == I->Pkg || Cache[Pkg].Install() == false)
+	       continue;
+	    toCrossgrade.emplace_back(&(*I), Pkg.FullName());
+	    break;
+	 }
+      }
+      for (auto C : toCrossgrade)
+      {
+	 // we never do purges on packages which are crossgraded, even if "requested"
+	 if (C.first->Op == Item::Purge)
+	 {
+	    C.first->Op = Item::Remove; // crossgrades should never be purged
+	    auto && Purges = approvedStates.Purge();
+	    auto const Ver = std::find_if(
+#if __GNUC__ >= 5 || (__GNUC_MINOR__ >= 9 && __GNUC__ >= 4)
+	       Purges.cbegin(), Purges.cend(),
+#else
+	       Purges.begin(), Purges.end(),
+#endif
+	       [&C](pkgCache::VerIterator const &V) { return V.ParentPkg() == C.first->Pkg; });
+	    approvedStates.Remove(*Ver);
+	    Purges.erase(Ver);
+	    auto && RemOp = PackageOps[C.first->Pkg.FullName()];
+	    if (RemOp.size() == 4)
+	    {
+	       RemOp.erase(std::next(RemOp.begin(), 2), RemOp.end());
+	       PackagesTotal -= 2;
+	    }
+	    else
+	    _error->Warning("Unexpected amount of planned ops for package %s: %lu", C.first->Pkg.FullName().c_str(), RemOp.size());
+	 }
+      }
+      if (crossgraded.empty() == false)
+      {
+	 auto const oldsize = List.size();
+	 List.erase(std::remove_if(List.begin(), PlanedEnd,
+	       [&crossgraded](Item const &i){
+		  return (i.Op == Item::Remove || i.Op == Item::Purge) &&
+		     crossgraded.find(i.Pkg->ID) != crossgraded.end();
+	       }), PlanedEnd);
+	 explicitIdx -= (oldsize - List.size());
+      }
+   }
+
+   APT::StateChanges currentStates;
+   if (_config->FindB("dpkg::selection::current::saveandrestore", true))
+   {
+      for (auto Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+	 if (Pkg->CurrentVer == 0)
+	    continue;
+	 else if (Pkg->SelectedState == pkgCache::State::Purge)
+	    currentStates.Purge(FindToBeRemovedVersion(Pkg));
+	 else if (Pkg->SelectedState == pkgCache::State::DeInstall)
+	    currentStates.Remove(FindToBeRemovedVersion(Pkg));
+      if (currentStates.empty() == false)
+      {
+	 APT::StateChanges cleanStates;
+	 for (auto && P: currentStates.Remove())
+	    cleanStates.Install(P);
+	 for (auto && P: currentStates.Purge())
+	    cleanStates.Install(P);
+	 if (cleanStates.Save(false) == false)
+	    return _error->Error("Couldn't clean the currently selected dpkg states");
+      }
+   }
+
+   if (_config->FindB("dpkg::selection::remove::approved", true))
+   {
+      if (approvedStates.Save(false) == false)
+      {
+	 _error->Error("Couldn't record the approved state changes as dpkg selection states");
+	 if (currentStates.Save(false) == false)
+	    _error->Error("Couldn't restore dpkg selection states which were present before this interaction!");
+	 return false;
+      }
+
+      List.erase(std::next(List.begin(), explicitIdx), List.end());
+
+      std::vector<bool> toBeRemoved(Cache.Head().PackageCount, false);
+      for (auto && I: approvedStates.Remove())
+	 toBeRemoved[I.ParentPkg()->ID] = true;
+      for (auto && I: approvedStates.Purge())
+	 toBeRemoved[I.ParentPkg()->ID] = true;
+
+      for (auto && I: List)
+	 if (I.Op == Item::Remove || I.Op == Item::Purge)
+	    toBeRemoved[I.Pkg->ID] = false;
+
+      bool const RemovePending = std::find(toBeRemoved.begin(), toBeRemoved.end(), true) != toBeRemoved.end();
+      bool const PurgePending = approvedStates.Purge().empty() == false;
+      if (RemovePending != false || PurgePending != false)
+	 List.emplace_back(Item::ConfigurePending, pkgCache::PkgIterator());
+      if (RemovePending)
+	 List.emplace_back(Item::RemovePending, pkgCache::PkgIterator());
+      if (PurgePending)
+	 List.emplace_back(Item::PurgePending, pkgCache::PkgIterator());
+
+      // support subpressing of triggers processing for special
+      // cases like d-i that runs the triggers handling manually
+      if (_config->FindB("DPkg::ConfigurePending", true))
+	 List.emplace_back(Item::ConfigurePending, pkgCache::PkgIterator());
+   }
+   bool const TriggersPending = _config->FindB("DPkg::TriggersPending", false);
+
+   d->stdin_is_dev_null = false;
+
+   // create log
+   OpenLog();
+
+   bool dpkgMultiArch = _system->MultiArchSupported();
+   bool dpkgProtectedField = debSystem::AssertFeature("protected-field");
+
+   // start pty magic before the loop
+   StartPtyMagic();
+
+   // Tell the progress that its starting and fork dpkg
+   d->progress->Start(d->master);
+
+   // this loop is runs once per dpkg operation
+   vector<Item>::const_iterator I = List.cbegin();
+   BuildDpkgCall Args;
+   while (I != List.end())
+   {
+      // Do all actions with the same Op in one run
+      vector<Item>::const_iterator J = I;
+      if (TriggersPending == true)
+	 for (; J != List.end(); ++J)
+	 {
+	    if (J->Op == I->Op)
+	       continue;
+	    if (J->Op != Item::TriggersPending)
+	       break;
+	    vector<Item>::const_iterator T = J + 1;
+	    if (T != List.end() && T->Op == I->Op)
+	       continue;
+	    break;
+	 }
+      else if (J->Op == Item::Remove || J->Op == Item::Purge)
+	 J = std::find_if(J, List.cend(), [](Item const &I) { return I.Op != Item::Remove && I.Op != Item::Purge; });
+      else
+	 J = std::find_if(J, List.cend(), [&J](Item const &I) { return I.Op != J->Op; });
+
+      Args.clearCallArguments();
+      Args.reserve((J - I) + 10);
+
+      int fd[2];
+      if (pipe(fd) != 0)
+	 return _error->Errno("pipe","Failed to create IPC pipe to dpkg");
+
+      Args.push_back("--status-fd");
+      Args.push_back(std::to_string(fd[1]));
+      unsigned long const Op = I->Op;
+
+      if (NoTriggers == true && I->Op != Item::TriggersPending &&
+	  (I->Op != Item::ConfigurePending || std::next(I) != List.end()))
+	 Args.push_back("--no-triggers");
+
+      switch (I->Op)
+      {
+	 case Item::Remove:
+	 case Item::Purge:
+	 Args.push_back("--force-depends");
+	 Args.push_back("--abort-after=1");
+	 if (std::any_of(I, J, ItemIsEssential))
+	    Args.push_back("--force-remove-essential");
+	 if (dpkgProtectedField && std::any_of(I, J, ItemIsProtected))
+	    Args.push_back("--force-remove-protected");
+	 Args.push_back("--remove");
+	 break;
+
+	 case Item::Configure:
+	 Args.push_back("--configure");
+	 break;
+
+	 case Item::ConfigurePending:
+	 Args.push_back("--configure");
+	 Args.push_back("--pending");
+	 break;
+
+	 case Item::TriggersPending:
+	 Args.push_back("--triggers-only");
+	 Args.push_back("--pending");
+	 break;
+
+	 case Item::RemovePending:
+	 Args.push_back("--remove");
+	 Args.push_back("--pending");
+	 break;
+
+	 case Item::PurgePending:
+	 Args.push_back("--purge");
+	 Args.push_back("--pending");
+	 break;
+
+	 case Item::Install:
+	 Args.push_back("--unpack");
+	 Args.push_back("--auto-deconfigure");
+	 break;
+      }
+
+      std::unique_ptr<char, decltype(&cleanUpTmpDir)> tmpdir_for_dpkg_recursive{nullptr, &cleanUpTmpDir};
+      std::string const dpkg_chroot_dir = _config->FindDir("DPkg::Chroot-Directory", "/");
+
+      // Write in the file or package names
+      if (I->Op == Item::Install)
+      {
+	 auto const installsToDo = J - I;
+	 if (dpkg_recursive_install == true && dpkg_recursive_install_min < installsToDo)
+	 {
+	    {
+	       std::string basetmpdir = (dpkg_chroot_dir == "/") ? GetTempDir() : flCombine(dpkg_chroot_dir, "tmp");
+	       std::string tmpdir;
+	       strprintf(tmpdir, "%s/apt-dpkg-install-XXXXXX", basetmpdir.c_str());
+	       tmpdir_for_dpkg_recursive.reset(strndup(tmpdir.data(), tmpdir.length()));
+	       if (mkdtemp(tmpdir_for_dpkg_recursive.get()) == nullptr)
+		  return _error->Errno("DPkg::Go", "mkdtemp of %s failed in preparation of calling dpkg unpack", tmpdir_for_dpkg_recursive.get());
+	    }
+
+	    char p = 1;
+	    for (auto c = installsToDo - 1; (c = c/10) != 0; ++p);
+	    for (unsigned long n = 0; I != J; ++n, ++I)
+	    {
+	       if (I->File[0] != '/')
+		  return _error->Error("Internal Error, Pathname to install is not absolute '%s'",I->File.c_str());
+	       auto file = flNotDir(I->File);
+	       if (flExtension(file) != "deb")
+		  file.append(".deb");
+	       std::string linkpath;
+	       if (dpkg_recursive_install_numbered)
+		  strprintf(linkpath, "%s/%.*lu-%s", tmpdir_for_dpkg_recursive.get(), p, n, file.c_str());
+	       else
+		  strprintf(linkpath, "%s/%s", tmpdir_for_dpkg_recursive.get(), file.c_str());
+	       std::string linktarget = I->File;
+	       if (dpkg_chroot_dir != "/") {
+		  char * fakechroot = getenv("FAKECHROOT");
+		  if (fakechroot != nullptr && strcmp(fakechroot, "true") == 0) {
+		     // if apt is run with DPkg::Chroot-Directory under
+		     // fakechroot, absolulte symbolic links must be prefixed
+		     // with the chroot path to be valid inside fakechroot
+		     strprintf(linktarget, "%s/%s", dpkg_chroot_dir.c_str(), I->File.c_str());
+		  }
+	       }
+	       if (symlink(linktarget.c_str(), linkpath.c_str()) != 0)
+		  return _error->Errno("DPkg::Go", "Symlinking %s to %s failed!", linktarget.c_str(), linkpath.c_str());
+	    }
+	    Args.push_back("--recursive");
+	    Args.push_back(debSystem::StripDpkgChrootDirectory(tmpdir_for_dpkg_recursive.get()));
+	 }
+	 else
+	 {
+	    for (;I != J && Args.bytes() < MaxArgBytes; ++I)
+	    {
+	       if (I->File[0] != '/')
+		  return _error->Error("Internal Error, Pathname to install is not absolute '%s'",I->File.c_str());
+	       Args.push_back(I->File.c_str());
+	    }
+	 }
+      }
+      else if (I->Op == Item::RemovePending)
+      {
+	 ++I;
+	 StripAlreadyDoneFrom(approvedStates.Remove());
+	 if (approvedStates.Remove().empty())
+	    continue;
+      }
+      else if (I->Op == Item::PurgePending)
+      {
+	 ++I;
+	 // explicit removes of packages without conffiles passthrough the purge states instantly, too.
+	 // Setting these non-installed packages up for purging generates 'unknown pkg' warnings from dpkg
+	 StripAlreadyDoneFrom(approvedStates.Purge());
+	 if (approvedStates.Purge().empty())
+	    continue;
+	 std::remove_reference<decltype(approvedStates.Remove())>::type approvedRemoves;
+	 std::swap(approvedRemoves, approvedStates.Remove());
+	 // we apply it again here as an explicit remove in the ordering will have cleared the purge state
+	 if (approvedStates.Save(false) == false)
+	 {
+	    _error->Error("Couldn't record the approved purges as dpkg selection states");
+	    if (currentStates.Save(false) == false)
+	       _error->Error("Couldn't restore dpkg selection states which were present before this interaction!");
+	    return false;
+	 }
+	 std::swap(approvedRemoves, approvedStates.Remove());
+      }
+      else
+      {
+	 string const nativeArch = _config->Find("APT::Architecture");
+	 auto const oldSize = I->Pkg.end() ? 0ull : Args.bytes();
+	 for (;I != J && Args.bytes() < MaxArgBytes; ++I)
+	 {
+	    if((*I).Pkg.end() == true)
+	       continue;
+	    if (I->Op == Item::Configure && disappearedPkgs.find(I->Pkg.FullName(true)) != disappearedPkgs.end())
+	       continue;
+	    // We keep this here to allow "smooth" transitions from e.g. multiarch dpkg/ubuntu to dpkg/debian
+	    if (dpkgMultiArch == false && (I->Pkg.Arch() == nativeArch ||
+					   strcmp(I->Pkg.Arch(), "all") == 0 ||
+					   strcmp(I->Pkg.Arch(), "none") == 0))
+	       Args.push_back(I->Pkg.Name());
+	    else if (Op == Item::Purge && I->Pkg->CurrentVer == 0)
+	       continue; // we purge later with --purge --pending, so if it isn't installed (aka rc-only), skip it here
+	    else if (strcmp(I->Pkg.Arch(), "none") == 0)
+	       Args.push_back(I->Pkg.Name()); // never arch-qualify a package without an arch
+	    else
+	    {
+	       pkgCache::VerIterator PkgVer;
+	       if (Op == Item::Remove || Op == Item::Purge)
+		  PkgVer = I->Pkg.CurrentVer();
+	       else
+		  PkgVer = Cache[I->Pkg].InstVerIter(Cache);
+	       if (PkgVer.end())
+	       {
+		  _error->Warning("Can not find PkgVer for '%s'", I->Pkg.Name());
+		  Args.push_back(I->Pkg.Name());
+		  continue;
+	       }
+	       Args.push_back(std::string(I->Pkg.Name()) + ":" + PkgVer.Arch());
+	    }
+	 }
+	 // skip configure action if all scheduled packages disappeared
+	 if (oldSize == Args.bytes())
+	    continue;
+      }
+
+      J = I;
+
+      if (noopDPkgInvocation == true)
+      {
+	 for (auto const a : Args)
+	    clog << a << ' ';
+	 clog << endl;
+	 close(fd[0]);
+	 close(fd[1]);
+	 continue;
+      }
+      cout << flush;
+      clog << flush;
+      cerr << flush;
+
+      /* Mask off sig int/quit. We do this because dpkg also does when
+         it forks scripts. What happens is that when you hit ctrl-c it sends
+	 it to all processes in the group. Since dpkg ignores the signal
+	 it doesn't die but we do! So we must also ignore it */
+      sighandler_t old_SIGQUIT = signal(SIGQUIT,SIG_IGN);
+      sighandler_t old_SIGINT = signal(SIGINT,SigINT);
+
+      // Check here for any SIGINT
+      if (pkgPackageManager::SigINTStop && (Op == Item::Remove || Op == Item::Purge || Op == Item::Install))
+         break;
+
+      // ignore SIGHUP as well (debian #463030)
+      sighandler_t old_SIGHUP = signal(SIGHUP,SIG_IGN);
+
+      // now run dpkg
+      d->progress->StartDpkg();
+      std::set<int> KeepFDs;
+      KeepFDs.insert(fd[1]);
+      MergeKeepFdsFromConfiguration(KeepFDs);
+      pid_t Child = ExecFork(KeepFDs);
+      if (Child == 0)
+      {
+	 // This is the child
+	 SetupSlavePtyMagic();
+	 close(fd[0]); // close the read end of the pipe
+
+	 debSystem::DpkgChrootDirectory();
+
+	 if (chdir(_config->FindDir("DPkg::Run-Directory","/").c_str()) != 0)
+	    _exit(100);
+
+	 if (_config->FindB("DPkg::FlushSTDIN",true) == true && isatty(STDIN_FILENO))
+	 {
+	    int Flags;
+            int dummy = 0;
+	    if ((Flags = fcntl(STDIN_FILENO,F_GETFL,dummy)) < 0)
+	       _exit(100);
+
+	    // Discard everything in stdin before forking dpkg
+	    if (fcntl(STDIN_FILENO,F_SETFL,Flags | O_NONBLOCK) < 0)
+	       _exit(100);
+
+	    while (read(STDIN_FILENO,&dummy,1) == 1);
+
+	    if (fcntl(STDIN_FILENO,F_SETFL,Flags & (~(long)O_NONBLOCK)) < 0)
+	       _exit(100);
+	 }
+
+	 // if color support isn't enabled/disabled explicitly tell
+	 // dpkg to use the same state apt is using for its color support
+	 if (_config->FindB("APT::Color", false) == true)
+	    setenv("DPKG_COLORS", "always", 0);
+	 else
+	    setenv("DPKG_COLORS", "never", 0);
+
+	 if (_system->IsLocked() == true) {
+	    setenv("DPKG_FRONTEND_LOCKED", "true", 1);
+	 }
+	 if (_config->Find("DPkg::Path", "").empty() == false)
+	    setenv("PATH", _config->Find("DPkg::Path", "").c_str(), 1);
+
+	 Args.execute("Could not exec dpkg!");
+      }
+
+      // we read from dpkg here
+      int const _dpkgin = fd[0];
+      close(fd[1]);                        // close the write end of the pipe
+      d->status_fd_reached_end_of_file = false;
+
+      // apply ionice
+      if (_config->FindB("DPkg::UseIoNice", false) == true)
+	 ionice(Child);
+
+      // setups fds
+      sigemptyset(&d->sigmask);
+      sigprocmask(SIG_BLOCK,&d->sigmask,&d->original_sigmask);
+
+      // the result of the waitpid call
+      int Status = 0;
+      int res;
+      bool waitpid_failure = false;
+      bool dpkg_finished = false;
+      do
+      {
+	 if (dpkg_finished == false)
+	 {
+	    if ((res = waitpid(Child, &Status, WNOHANG)) == Child)
+	       dpkg_finished = true;
+	    else if (res < 0)
+	    {
+	       // error handling, waitpid returned -1
+	       if (errno == EINTR)
+		  continue;
+	       waitpid_failure = true;
+	       break;
+	    }
+	 }
+	 if (dpkg_finished && d->status_fd_reached_end_of_file)
+	    break;
+
+	 // wait for input or output here
+	 fd_set rfds;
+	 FD_ZERO(&rfds);
+	 if (d->master >= 0 && d->direct_stdin == false && d->stdin_is_dev_null == false)
+	    FD_SET(STDIN_FILENO, &rfds);
+	 FD_SET(_dpkgin, &rfds);
+	 if(d->master >= 0)
+	    FD_SET(d->master, &rfds);
+	 struct timespec tv;
+	 tv.tv_sec = 0;
+	 tv.tv_nsec = d->progress->GetPulseInterval();
+	 auto const select_ret = pselect(max(d->master, _dpkgin)+1, &rfds, NULL, NULL,
+			      &tv, &d->original_sigmask);
+         d->progress->Pulse();
+	 if (select_ret == 0)
+	    continue;
+	 else if (select_ret < 0 && errno == EINTR)
+	    continue;
+	 else if (select_ret < 0)
+	 {
+	    perror("select() returned error");
+	    continue;
+	 }
+
+	 if(d->master >= 0 && FD_ISSET(d->master, &rfds))
+	    DoTerminalPty(d->master);
+	 if(d->master >= 0 && FD_ISSET(0, &rfds))
+	    DoStdin(d->master);
+	 if(FD_ISSET(_dpkgin, &rfds))
+	    DoDpkgStatusFd(_dpkgin);
+
+      } while (true);
+      close(_dpkgin);
+
+      // Restore sig int/quit
+      signal(SIGQUIT,old_SIGQUIT);
+      signal(SIGINT,old_SIGINT);
+      signal(SIGHUP,old_SIGHUP);
+
+      if (waitpid_failure == true)
+      {
+	 strprintf(d->dpkg_error, "Sub-process %s couldn't be waited for.",Args.front());
+	 _error->Error("%s", d->dpkg_error.c_str());
+	 break;
+      }
+
+      // Check for an error code.
+      if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
+      {
+	 // if it was set to "keep-dpkg-running" then we won't return
+	 // here but keep the loop going and just report it as a error
+	 // for later
+	 bool const stopOnError = _config->FindB("Dpkg::StopOnError",true);
+
+	 if (WIFSIGNALED(Status) != 0 && WTERMSIG(Status) == SIGSEGV)
+	    strprintf(d->dpkg_error, "Sub-process %s received a segmentation fault.",Args.front());
+	 else if (WIFEXITED(Status) != 0)
+	    strprintf(d->dpkg_error, "Sub-process %s returned an error code (%u)",Args.front(),WEXITSTATUS(Status));
+	 else
+	    strprintf(d->dpkg_error, "Sub-process %s exited unexpectedly",Args.front());
+	 _error->Error("%s", d->dpkg_error.c_str());
+
+	 if(stopOnError)
+	    break;
+      }
+   }
+   // dpkg is done at this point
+   StopPtyMagic();
+   CloseLog();
+
+   if (d->dpkg_error.empty() == false)
+   {
+      // no point in resetting packages we already completed removal for
+      StripAlreadyDoneFrom(approvedStates.Remove());
+      StripAlreadyDoneFrom(approvedStates.Purge());
+      APT::StateChanges undo;
+      auto && undoRem = approvedStates.Remove();
+      std::move(undoRem.begin(), undoRem.end(), std::back_inserter(undo.Install()));
+      auto && undoPur = approvedStates.Purge();
+      std::move(undoPur.begin(), undoPur.end(), std::back_inserter(undo.Install()));
+      approvedStates.clear();
+      if (undo.Save(false) == false)
+	 _error->Error("Couldn't revert dpkg selection for approved remove/purge after an error was encountered!");
+   }
+
+   StripAlreadyDoneFrom(currentStates.Remove());
+   StripAlreadyDoneFrom(currentStates.Purge());
+   if (currentStates.Save(false) == false)
+      _error->Error("Couldn't restore dpkg selection states which were present before this interaction!");
+
+   if (pkgPackageManager::SigINTStop)
+       _error->Warning(_("Operation was interrupted before it could finish"));
+
+   if (noopDPkgInvocation == false)
+   {
+      if (d->dpkg_error.empty() && (PackagesDone + 1) != PackagesTotal)
+      {
+	 std::string pkglist;
+	 for (auto const &PO: PackageOps)
+	    if (PO.second.size() != PackageOpsDone[PO.first])
+	    {
+	       if (pkglist.empty() == false)
+		  pkglist.append(" ");
+	       pkglist.append(PO.first);
+	    }
+	 /* who cares about correct progress? As we depend on it for skipping actions
+	    our parsing should be correct. People will no doubt be confused if they see
+	    this message, but the dpkg warning about unknown packages isn't much better
+	    from a user POV and combined we might have a chance to figure out what is wrong */
+	 _error->Warning("APT had planned for dpkg to do more than it reported back (%u vs %u).\n"
+	       "Affected packages: %s", PackagesDone, PackagesTotal, pkglist.c_str());
+      }
+
+      std::string const oldpkgcache = _config->FindFile("Dir::cache::pkgcache");
+      if (oldpkgcache.empty() == false && RealFileExists(oldpkgcache) == true &&
+	  RemoveFile("pkgDPkgPM::Go", oldpkgcache))
+      {
+	 std::string const srcpkgcache = _config->FindFile("Dir::cache::srcpkgcache");
+	 if (srcpkgcache.empty() == false && RealFileExists(srcpkgcache) == true)
+	 {
+	    _error->PushToStack();
+	    pkgCacheFile CacheFile;
+	    CacheFile.BuildCaches(NULL, true);
+	    _error->RevertToStack();
+	 }
+      }
+   }
+
+   // disappearing packages can forward their auto-bit
+   if (disappearedPkgs.empty() == false)
+      Cache.writeStateFile(NULL);
+
+   d->progress->Stop();
+
+   if (RunScripts("DPkg::Post-Invoke") == false)
+      return false;
+
+   return d->dpkg_error.empty();
+}
+
+void SigINT(int /*sig*/) {
+   pkgPackageManager::SigINTStop = true;
+}
+									/*}}}*/
+// pkgDpkgPM::Reset - Dump the contents of the command list		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgDPkgPM::Reset()
+{
+   List.erase(List.begin(),List.end());
+}
+									/*}}}*/
+// pkgDpkgPM::WriteApportReport - write out error report pkg failure	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgDPkgPM::WriteApportReport(const char *pkgpath, const char *errormsg)
+{
+   // If apport doesn't exist or isn't installed do nothing
+   // This e.g. prevents messages in 'universes' without apport
+   pkgCache::PkgIterator apportPkg = Cache.FindPkg("apport");
+   if (apportPkg.end() == true || apportPkg->CurrentVer == 0)
+      return;
+
+   string pkgname, reportfile, pkgver, arch;
+   string::size_type pos;
+   FILE *report;
+
+   if (_config->FindB("Dpkg::ApportFailureReport", true) == false)
+   {
+      std::clog << "configured to not write apport reports" << std::endl;
+      return;
+   }
+
+   // only report the first errors
+   if(pkgFailures > _config->FindI("APT::Apport::MaxReports", 3))
+   {
+      std::clog << _("No apport report written because MaxReports is reached already") << std::endl;
+      return;
+   }
+
+   // check if its not a follow up error
+   const char *needle = dgettext("dpkg", "dependency problems - leaving unconfigured");
+   if(strstr(errormsg, needle) != NULL) {
+      std::clog << _("No apport report written because the error message indicates its a followup error from a previous failure.") << std::endl;
+      return;
+   }
+
+   // do not report disk-full failures
+   if(strstr(errormsg, strerror(ENOSPC)) != NULL) {
+      std::clog << _("No apport report written because the error message indicates a disk full error") << std::endl;
+      return;
+   }
+
+   // do not report out-of-memory failures
+   if(strstr(errormsg, strerror(ENOMEM)) != NULL ||
+      strstr(errormsg, "failed to allocate memory") != NULL) {
+      std::clog << _("No apport report written because the error message indicates a out of memory error") << std::endl;
+      return;
+   }
+
+   // do not report bugs regarding inaccessible local files
+   if(strstr(errormsg, strerror(ENOENT)) != NULL ||
+      strstr(errormsg, "cannot access archive") != NULL) {
+      std::clog << _("No apport report written because the error message indicates an issue on the local system") << std::endl;
+      return;
+   }
+
+   // do not report errors encountered when decompressing packages
+   if(strstr(errormsg, "--fsys-tarfile returned error exit status 2") != NULL) {
+      std::clog << _("No apport report written because the error message indicates an issue on the local system") << std::endl;
+      return;
+   }
+
+   // do not report dpkg I/O errors, this is a format string, so we compare
+   // the prefix and the suffix of the error with the dpkg error message
+   vector<string> io_errors;
+   io_errors.push_back(string("failed to read"));
+   io_errors.push_back(string("failed to write"));
+   io_errors.push_back(string("failed to seek"));
+   io_errors.push_back(string("unexpected end of file or stream"));
+
+   for (vector<string>::iterator I = io_errors.begin(); I != io_errors.end(); ++I)
+   {
+      vector<string> list = VectorizeString(dgettext("dpkg", (*I).c_str()), '%');
+      if (list.size() > 1) {
+         // we need to split %s, VectorizeString only allows char so we need
+         // to kill the "s" manually
+         if (list[1].size() > 1) {
+            list[1].erase(0, 1);
+            if(strstr(errormsg, list[0].c_str()) &&
+               strstr(errormsg, list[1].c_str())) {
+               std::clog << _("No apport report written because the error message indicates a dpkg I/O error") << std::endl;
+               return;
+            }
+         }
+      }
+   }
+
+   // get the pkgname and reportfile
+   pkgname = flNotDir(pkgpath);
+   pos = pkgname.find('_');
+   if(pos != string::npos)
+      pkgname = pkgname.substr(0, pos);
+
+   // find the package version and source package name
+   pkgCache::PkgIterator Pkg = Cache.FindPkg(pkgname);
+   if (Pkg.end() == true)
+   {
+      if (pos == std::string::npos || _config->FindB("dpkg::install::recursive::numbered", true) == false)
+	 return;
+      auto const dash = pkgname.find_first_not_of("0123456789");
+      if (dash == std::string::npos || pkgname[dash] != '-')
+	 return;
+      pkgname.erase(0, dash + 1);
+      Pkg = Cache.FindPkg(pkgname);
+      if (Pkg.end() == true)
+	 return;
+   }
+   pkgCache::VerIterator Ver = Cache.GetCandidateVersion(Pkg);
+   if (Ver.end() == true)
+      return;
+   pkgver = Ver.VerStr() == NULL ? "unknown" : Ver.VerStr();
+
+   // if the file exists already, we check:
+   // - if it was reported already (touched by apport). 
+   //   If not, we do nothing, otherwise
+   //    we overwrite it. This is the same behaviour as apport
+   // - if we have a report with the same pkgversion already
+   //   then we skip it
+   _config->CndSet("Dir::Apport", "var/crash");
+   reportfile = flCombine(_config->FindDir("Dir::Apport", "var/crash"), pkgname+".0.crash");
+   if(FileExists(reportfile))
+   {
+      struct stat buf;
+      char strbuf[255];
+
+      // check atime/mtime
+      stat(reportfile.c_str(), &buf);
+      if(buf.st_mtime > buf.st_atime)
+	 return;
+
+      // check if the existing report is the same version
+      report = fopen(reportfile.c_str(),"r");
+      while(fgets(strbuf, sizeof(strbuf), report) != NULL)
+      {
+	 if(strstr(strbuf,"Package:") == strbuf)
+	 {
+	    char pkgname[255], version[255];
+	    if(sscanf(strbuf, "Package: %254s %254s", pkgname, version) == 2)
+	       if(strcmp(pkgver.c_str(), version) == 0)
+	       {
+		  fclose(report);
+		  return;
+	       }
+	 }
+      }
+      fclose(report);
+   }
+
+   // now write the report
+   arch = _config->Find("APT::Architecture");
+   report = fopen(reportfile.c_str(),"w");
+   if(report == NULL)
+      return;
+   if(_config->FindB("DPkgPM::InitialReportOnly",false) == true)
+      chmod(reportfile.c_str(), 0);
+   else
+      chmod(reportfile.c_str(), 0600);
+   fprintf(report, "ProblemType: Package\n");
+   fprintf(report, "Architecture: %s\n", arch.c_str());
+   time_t now = time(NULL);
+   char ctime_buf[26];	// need at least 26 bytes according to ctime(3)
+   fprintf(report, "Date: %s" , ctime_r(&now, ctime_buf));
+   fprintf(report, "Package: %s %s\n", pkgname.c_str(), pkgver.c_str());
+   fprintf(report, "SourcePackage: %s\n", Ver.SourcePkgName());
+   fprintf(report, "ErrorMessage:\n %s\n", errormsg);
+
+   // ensure that the log is flushed
+   if(d->term_out)
+      fflush(d->term_out);
+
+   // attach terminal log it if we have it
+   string logfile_name = _config->FindFile("Dir::Log::Terminal", "/dev/null");
+   if (logfile_name != "/dev/null")
+   {
+      FILE *log = NULL;
+
+      fprintf(report, "DpkgTerminalLog:\n");
+      log = fopen(logfile_name.c_str(),"r");
+      if(log != NULL)
+      {
+	 char buf[1024];
+	 while( fgets(buf, sizeof(buf), log) != NULL)
+	    fprintf(report, " %s", buf);
+         fprintf(report, " \n");
+	 fclose(log);
+      }
+   }
+
+   // attach history log it if we have it
+   string histfile_name = _config->FindFile("Dir::Log::History", "/dev/null");
+   if (histfile_name != "/dev/null")
+   {
+      fprintf(report, "DpkgHistoryLog:\n");
+      FILE* log = fopen(histfile_name.c_str(),"r");
+      if(log != NULL)
+      {
+	 char buf[1024];
+	 while( fgets(buf, sizeof(buf), log) != NULL)
+	    fprintf(report, " %s", buf);
+	 fclose(log);
+      }
+   }
+
+   // log the ordering, see dpkgpm.h and the "Ops" enum there
+   fprintf(report, "AptOrdering:\n");
+   for (auto && I : List)
+   {
+      char const * opstr = nullptr;
+      switch (I.Op)
+      {
+	 case Item::Install: opstr = "Install"; break;
+	 case Item::Configure: opstr = "Configure"; break;
+	 case Item::Remove: opstr = "Remove"; break;
+	 case Item::Purge: opstr = "Purge"; break;
+	 case Item::ConfigurePending: opstr = "ConfigurePending"; break;
+	 case Item::TriggersPending: opstr = "TriggersPending"; break;
+	 case Item::RemovePending: opstr = "RemovePending"; break;
+	 case Item::PurgePending: opstr = "PurgePending"; break;
+      }
+      auto const pkgname = I.Pkg.end() ? "NULL" : I.Pkg.FullName();
+      fprintf(report, " %s: %s\n", pkgname.c_str(), opstr);
+   }
+
+   // attach dmesg log (to learn about segfaults)
+   if (FileExists("/bin/dmesg"))
+   {
+      fprintf(report, "Dmesg:\n");
+      FILE *log = popen("/bin/dmesg","r");
+      if(log != NULL)
+      {
+	 char buf[1024];
+	 while( fgets(buf, sizeof(buf), log) != NULL)
+	    fprintf(report, " %s", buf);
+	 pclose(log);
+      }
+   }
+
+   // attach df -l log (to learn about filesystem status)
+   if (FileExists("/bin/df"))
+   {
+
+      fprintf(report, "Df:\n");
+      FILE *log = popen("/bin/df -l -x squashfs","r");
+      if(log != NULL)
+      {
+	 char buf[1024];
+	 while( fgets(buf, sizeof(buf), log) != NULL)
+	    fprintf(report, " %s", buf);
+	 pclose(log);
+      }
+   }
+
+   fclose(report);
+
+}
+									/*}}}*/
diff --git a/apt-pkg/deb/dpkgpm.h b/apt-pkg/deb/dpkgpm.h
new file mode 100644
index 0000000..caf7d35
--- /dev/null
+++ b/apt-pkg/deb/dpkgpm.h
@@ -0,0 +1,135 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   DPKG Package Manager - Provide an interface to dpkg
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DPKGPM_H
+#define PKGLIB_DPKGPM_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <map>
+#include <string>
+#include <vector>
+#include <stdio.h>
+
+
+class pkgDepCache;
+namespace APT { namespace Progress { class PackageManager; } }
+
+
+class pkgDPkgPMPrivate;
+
+
+class APT_PUBLIC pkgDPkgPM : public pkgPackageManager
+{
+   private:
+   pkgDPkgPMPrivate * const d;
+
+   /** \brief record the disappear action and handle accordingly
+
+      dpkg let packages disappear then they have no files any longer and
+      nothing depends on them. We need to collect this as dpkg as well as
+      APT doesn't know beforehand that the package will disappear, so the
+      only possible option is to tell the user afterwards about it.
+      To enhance the experience we also try to forward the auto-install
+      flag so the disappear-causer(s) are not autoremoved next time -
+      for the transfer to happen the disappeared version needs to depend
+      on the package the flag should be forwarded to and this package
+      needs to declare a Replaces on the disappeared package.
+      \param pkgname Name of the package that disappeared
+   */
+   APT_HIDDEN void handleDisappearAction(std::string const &pkgname);
+   APT_HIDDEN void handleCrossUpgradeAction(std::string const &pkgname);
+
+   protected:
+   int pkgFailures;
+
+   // progress reporting
+   struct DpkgState 
+   {
+      const char *state;     // the dpkg state (e.g. "unpack")
+      const char *str;       // the human readable translation of the state
+   };
+
+   // the dpkg states that the pkg will run through, the string is 
+   // the package, the vector contains the dpkg states that the package
+   // will go through
+   std::map<std::string,std::vector<struct DpkgState> > PackageOps;
+   // the dpkg states that are already done; the string is the package
+   // the int is the state that is already done (e.g. a package that is
+   // going to be install is already in state "half-installed")
+   std::map<std::string,unsigned int> PackageOpsDone;
+
+   // progress reporting
+   unsigned int PackagesDone;
+   unsigned int PackagesTotal;
+
+   public:
+   struct Item
+   {
+      enum Ops {Install, Configure, Remove, Purge, ConfigurePending, TriggersPending,
+         RemovePending, PurgePending } Op;
+      std::string File;
+      PkgIterator Pkg;
+      Item(Ops Op,PkgIterator Pkg,std::string File = "") : Op(Op),
+            File(File), Pkg(Pkg) {};
+      Item() {};
+   };
+   protected:
+   std::vector<Item> List;
+
+   // Helpers
+   bool RunScriptsWithPkgs(const char *Cnf);
+   bool SendPkgsInfo(FILE * const F, unsigned int const &Version);
+   void WriteHistoryTag(std::string const &tag, std::string value);
+   std::string ExpandShortPackageName(pkgDepCache &Cache,
+                                      const std::string &short_pkgname);
+
+   // Terminal progress 
+   void SendTerminalProgress(float percentage);
+
+   // apport integration
+   void WriteApportReport(const char *pkgpath, const char *errormsg);
+
+   // dpkg log
+   bool OpenLog();
+   bool CloseLog();
+
+   // helper
+   void BuildPackagesProgressMap();
+   void StartPtyMagic();
+   void SetupSlavePtyMagic();
+   void StopPtyMagic();
+   
+   // input processing
+   void DoStdin(int master);
+   void DoTerminalPty(int master);
+   void DoDpkgStatusFd(int statusfd);
+   void ProcessDpkgStatusLine(char *line);
+
+   // The Actual installation implementation
+   virtual bool Install(PkgIterator Pkg,std::string File) APT_OVERRIDE;
+   virtual bool Configure(PkgIterator Pkg) APT_OVERRIDE;
+   virtual bool Remove(PkgIterator Pkg,bool Purge = false) APT_OVERRIDE;
+
+   virtual bool Go(APT::Progress::PackageManager *progress) APT_OVERRIDE;
+
+   virtual void Reset() APT_OVERRIDE;
+   
+   public:
+
+   explicit pkgDPkgPM(pkgDepCache *Cache);
+   virtual ~pkgDPkgPM();
+
+   APT_HIDDEN static bool ExpandPendingCalls(std::vector<Item> &List, pkgDepCache &Cache);
+};
+
+void SigINT(int sig);
+
+#endif
diff --git a/apt-pkg/depcache.cc b/apt-pkg/depcache.cc
new file mode 100644
index 0000000..322bf1b
--- /dev/null
+++ b/apt-pkg/depcache.cc
@@ -0,0 +1,2564 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Dependency Cache - Caches Dependency information.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cachefile.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/prettyprinters.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+#include <apt-pkg/version.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <algorithm>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <iterator>
+#include <list>
+#include <set>
+#include <string>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+#include <stdio.h>
+#include <string.h>
+
+#include <sys/stat.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+// helper for kernel autoremoval				  	/*{{{*/
+
+/** \brief Returns \b true for packages matching a regular
+ *  expression in APT::NeverAutoRemove.
+ */
+class DefaultRootSetFunc2 : public pkgDepCache::DefaultRootSetFunc
+{
+   std::unique_ptr<APT::CacheFilter::Matcher> Kernels;
+
+   public:
+   DefaultRootSetFunc2(pkgCache *cache) : Kernels(APT::KernelAutoRemoveHelper::GetProtectedKernelsFilter(cache)){};
+   virtual ~DefaultRootSetFunc2(){};
+
+   bool InRootSet(const pkgCache::PkgIterator &pkg) APT_OVERRIDE { return pkg.end() == false && ((*Kernels)(pkg) || DefaultRootSetFunc::InRootSet(pkg)); };
+};
+
+									/*}}}*/
+// helper for Install-Recommends-Sections and Never-MarkAuto-Sections	/*{{{*/
+// FIXME: Has verbatim copy in cmdline/apt-mark.cc
+static bool ConfigValueInSubTree(const char* SubTree, std::string_view const needle)
+{
+   if (needle.empty())
+      return false;
+   Configuration::Item const *Opts = _config->Tree(SubTree);
+   if (Opts != nullptr && Opts->Child != nullptr)
+   {
+      Opts = Opts->Child;
+      for (; Opts != nullptr; Opts = Opts->Next)
+      {
+	 if (Opts->Value.empty())
+	    continue;
+	 if (needle == Opts->Value)
+	    return true;
+      }
+   }
+   return false;
+}
+static bool SectionInSubTree(char const * const SubTree, std::string_view Needle)
+{
+   if (ConfigValueInSubTree(SubTree, Needle))
+      return true;
+   auto const sub = Needle.rfind('/');
+   if (sub == std::string_view::npos)
+   {
+      std::string special{"/"};
+      special.append(Needle);
+      return ConfigValueInSubTree(SubTree, special);
+   }
+   return ConfigValueInSubTree(SubTree, Needle.substr(sub + 1));
+}
+									/*}}}*/
+pkgDepCache::ActionGroup::ActionGroup(pkgDepCache &cache) :		/*{{{*/
+  d(NULL), cache(cache), released(false)
+{
+  cache.IncreaseActionGroupLevel();
+}
+
+void pkgDepCache::ActionGroup::release()
+{
+  if(released)
+     return;
+  released = true;
+  if (cache.DecreaseActionGroupLevel() == 0)
+     cache.MarkAndSweep();
+}
+
+pkgDepCache::ActionGroup::~ActionGroup()
+{
+  release();
+}
+int pkgDepCache::IncreaseActionGroupLevel()
+{
+   return ++group_level;
+}
+int pkgDepCache::DecreaseActionGroupLevel()
+{
+   if(group_level == 0)
+   {
+      std::cerr << "W: Unbalanced action groups, expect badness\n";
+      return -1;
+   }
+   return --group_level;
+}
+									/*}}}*/
+// DepCache::pkgDepCache - Constructors					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+
+struct pkgDepCache::Private
+{
+   std::unique_ptr<InRootSetFunc> inRootSetFunc;
+   std::unique_ptr<APT::CacheFilter::Matcher> IsAVersionedKernelPackage, IsProtectedKernelPackage;
+};
+pkgDepCache::pkgDepCache(pkgCache *const pCache, Policy *const Plcy) : group_level(0), Cache(pCache), PkgState(0), DepState(0),
+								       iUsrSize(0), iDownloadSize(0), iInstCount(0), iDelCount(0), iKeepCount(0),
+								       iBrokenCount(0), iPolicyBrokenCount(0), iBadCount(0), d(new Private)
+{
+   DebugMarker = _config->FindB("Debug::pkgDepCache::Marker", false);
+   DebugAutoInstall = _config->FindB("Debug::pkgDepCache::AutoInstall", false);
+   delLocalPolicy = 0;
+   LocalPolicy = Plcy;
+   if (LocalPolicy == 0)
+      delLocalPolicy = LocalPolicy = new Policy;
+}
+									/*}}}*/
+// DepCache::~pkgDepCache - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgDepCache::~pkgDepCache()
+{
+   delete [] PkgState;
+   delete [] DepState;
+   delete delLocalPolicy;
+   delete d;
+}
+									/*}}}*/
+bool pkgDepCache::CheckConsistency(char const *const msgtag)		/*{{{*/
+{
+   auto const OrigPkgState = PkgState;
+   auto const OrigDepState = DepState;
+
+   PkgState = new StateCache[Head().PackageCount];
+   DepState = new unsigned char[Head().DependsCount];
+   memset(PkgState,0,sizeof(*PkgState)*Head().PackageCount);
+   memset(DepState,0,sizeof(*DepState)*Head().DependsCount);
+
+   auto const origUsrSize = iUsrSize;
+   auto const origDownloadSize = iDownloadSize;
+   auto const origInstCount = iInstCount;
+   auto const origDelCount = iDelCount;
+   auto const origKeepCount = iKeepCount;
+   auto const origBrokenCount = iBrokenCount;
+   auto const origPolicyBrokenCount = iPolicyBrokenCount;
+   auto const origBadCount = iBadCount;
+
+   for (PkgIterator I = PkgBegin(); not I.end(); ++I)
+   {
+      auto &State = PkgState[I->ID];
+      auto const &OrigState = OrigPkgState[I->ID];
+      State.iFlags = OrigState.iFlags;
+
+      State.CandidateVer = OrigState.CandidateVer;
+      State.InstallVer = OrigState.InstallVer;
+      State.Mode = OrigState.Mode;
+      State.Update(I,*this);
+      State.Status = OrigState.Status;
+   }
+   PerformDependencyPass(nullptr);
+
+   _error->PushToStack();
+#define APT_CONSISTENCY_CHECK(VAR,STR) \
+   if (orig##VAR != i##VAR) \
+      _error->Warning("Internal Inconsistency in pkgDepCache: " #VAR " " STR " vs " STR " (%s)", i##VAR, orig##VAR, msgtag)
+   APT_CONSISTENCY_CHECK(UsrSize, "%lld");
+   APT_CONSISTENCY_CHECK(DownloadSize, "%lld");
+   APT_CONSISTENCY_CHECK(InstCount, "%lu");
+   APT_CONSISTENCY_CHECK(DelCount, "%lu");
+   APT_CONSISTENCY_CHECK(KeepCount, "%lu");
+   APT_CONSISTENCY_CHECK(BrokenCount, "%lu");
+   APT_CONSISTENCY_CHECK(PolicyBrokenCount, "%lu");
+   APT_CONSISTENCY_CHECK(BadCount, "%lu");
+#undef APT_CONSISTENCY_CHECK
+
+   for (PkgIterator P = PkgBegin(); not P.end(); ++P)
+   {
+      auto const &State = PkgState[P->ID];
+      auto const &OrigState = OrigPkgState[P->ID];
+      if (State.Status != OrigState.Status)
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Status of %s is %d vs %d (%s)", P.FullName().c_str(), State.Status, OrigState.Status, msgtag);
+      if (State.NowBroken() != OrigState.NowBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Now broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.NowPolicyBroken() != OrigState.NowPolicyBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Now policy broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.InstBroken() != OrigState.InstBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Install broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.InstPolicyBroken() != OrigState.InstPolicyBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Install broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+   }
+
+   auto inconsistent = _error->PendingError();
+   _error->MergeWithStack();
+
+   delete[] PkgState;
+   delete[] DepState;
+   PkgState = OrigPkgState;
+   DepState = OrigDepState;
+   iUsrSize = origUsrSize;
+   iDownloadSize = origDownloadSize;
+   iInstCount = origInstCount;
+   iDelCount = origDelCount;
+   iKeepCount = origKeepCount;
+   iBrokenCount = origBrokenCount;
+   iPolicyBrokenCount = origPolicyBrokenCount;
+   iBadCount = origBadCount;
+
+   return not inconsistent;
+}
+									/*}}}*/
+// DepCache::Init - Generate the initial extra structures.		/*{{{*/
+// ---------------------------------------------------------------------
+/* This allocats the extension buffers and initializes them. */
+bool pkgDepCache::Init(OpProgress * const Prog)
+{
+   // Suppress mark updates during this operation (just in case) and
+   // run a mark operation when Init terminates.
+   ActionGroup actions(*this);
+
+   delete [] PkgState;
+   delete [] DepState;
+   PkgState = new StateCache[Head().PackageCount];
+   DepState = new unsigned char[Head().DependsCount];
+   memset(PkgState,0,sizeof(*PkgState)*Head().PackageCount);
+   memset(DepState,0,sizeof(*DepState)*Head().DependsCount);
+
+   if (Prog != 0)
+   {
+      Prog->OverallProgress(0,2*Head().PackageCount,Head().PackageCount,
+			    _("Building dependency tree"));
+      Prog->SubProgress(Head().PackageCount,_("Candidate versions"));
+   }
+
+   /* Set the current state of everything. In this state all of the
+      packages are kept exactly as is. See AllUpgrade */
+   int Done = 0;
+   for (PkgIterator I = PkgBegin(); I.end() != true; ++I, ++Done)
+   {
+      if (Prog != 0 && Done%20 == 0)
+	 Prog->Progress(Done);
+
+      // Find the proper cache slot
+      StateCache &State = PkgState[I->ID];
+      State.iFlags = 0;
+
+      // Figure out the install version
+      State.CandidateVer = LocalPolicy->GetCandidateVer(I);
+      State.InstallVer = I.CurrentVer();
+      State.Mode = ModeKeep;
+
+      State.Update(I,*this);
+   }
+
+   if (Prog != 0)
+   {
+      Prog->OverallProgress(Head().PackageCount,2*Head().PackageCount,
+			    Head().PackageCount,
+			    _("Building dependency tree"));
+      Prog->SubProgress(Head().PackageCount,_("Dependency generation"));
+   }
+
+   Update(Prog);
+
+   if(Prog != 0)
+      Prog->Done();
+
+   return true;
+}
+									/*}}}*/
+bool pkgDepCache::readStateFile(OpProgress * const Prog)		/*{{{*/
+{
+   FileFd state_file;
+   string const state = _config->FindFile("Dir::State::extended_states");
+   if(RealFileExists(state)) {
+      state_file.Open(state, FileFd::ReadOnly, FileFd::Extension);
+      off_t const file_size = state_file.Size();
+      if(Prog != NULL)
+      {
+	 Prog->Done();
+	 Prog->OverallProgress(0, file_size, 1,
+			       _("Reading state information"));
+      }
+
+      pkgTagFile tagfile(&state_file);
+      pkgTagSection section;
+      off_t amt = 0;
+      bool const debug_autoremove = _config->FindB("Debug::pkgAutoRemove",false);
+      while(tagfile.Step(section)) {
+	 auto const pkgname = section.Find(pkgTagSection::Key::Package);
+	 auto pkgarch = section.Find(pkgTagSection::Key::Architecture);
+	 if (pkgarch.empty() == true)
+	    pkgarch = "any";
+	 pkgCache::PkgIterator pkg = Cache->FindPkg(pkgname, pkgarch);
+	 // Silently ignore unknown packages and packages with no actual version.
+	 if(pkg.end() == true || pkg->VersionList == 0)
+	    continue;
+
+	 short const reason = section.FindI("Auto-Installed", 0);
+	 if(reason > 0)
+	 {
+	    PkgState[pkg->ID].Flags |= Flag::Auto;
+	    if (unlikely(debug_autoremove))
+	       std::clog << "Auto-Installed : " << pkg.FullName() << std::endl;
+	    if (pkgarch == "any")
+	    {
+	       pkgCache::GrpIterator G = pkg.Group();
+	       for (pkg = G.NextPkg(pkg); pkg.end() != true; pkg = G.NextPkg(pkg))
+		  if (pkg->VersionList != 0)
+		     PkgState[pkg->ID].Flags |= Flag::Auto;
+	    }
+	 }
+	 amt += section.size();
+	 if(Prog != NULL)
+	    Prog->OverallProgress(amt, file_size, 1, 
+				  _("Reading state information"));
+      }
+      if(Prog != NULL)
+	 Prog->OverallProgress(file_size, file_size, 1,
+			       _("Reading state information"));
+   }
+
+   return true;
+}
+									/*}}}*/
+bool pkgDepCache::writeStateFile(OpProgress * const /*prog*/, bool const InstalledOnly)	/*{{{*/
+{
+   bool const debug_autoremove = _config->FindB("Debug::pkgAutoRemove",false);
+   
+   if(debug_autoremove)
+      std::clog << "pkgDepCache::writeStateFile()" << std::endl;
+
+   FileFd StateFile;
+   string const state = _config->FindFile("Dir::State::extended_states");
+   if (CreateAPTDirectoryIfNeeded(_config->FindDir("Dir::State"), flNotFile(state)) == false)
+      return false;
+
+   // if it does not exist, create a empty one
+   if(!RealFileExists(state))
+   {
+      StateFile.Open(state, FileFd::WriteAtomic, FileFd::Extension);
+      StateFile.Close();
+   }
+
+   // open it
+   if (!StateFile.Open(state, FileFd::ReadOnly, FileFd::Extension))
+      return _error->Error(_("Failed to open StateFile %s"),
+			   state.c_str());
+
+   FileFd OutFile(state, FileFd::ReadWrite | FileFd::Atomic, FileFd::Extension);
+   if (OutFile.IsOpen() == false || OutFile.Failed() == true)
+      return _error->Error(_("Failed to write temporary StateFile %s"), state.c_str());
+
+   // first merge with the existing sections
+   pkgTagFile tagfile(&StateFile);
+   pkgTagSection section;
+   std::set<string> pkgs_seen;
+   while(tagfile.Step(section)) {
+	 auto const pkgname = section.Find(pkgTagSection::Key::Package);
+	 auto pkgarch = section.Find(pkgTagSection::Key::Architecture);
+	 if (pkgarch.empty() == true)
+	    pkgarch = "native";
+	 // Silently ignore unknown packages and packages with no actual
+	 // version.
+	 pkgCache::PkgIterator pkg = Cache->FindPkg(pkgname, pkgarch);
+	 if(pkg.end() || pkg.VersionList().end())
+	    continue;
+	 StateCache const &P = PkgState[pkg->ID];
+	 bool newAuto = (P.Flags & Flag::Auto);
+	 // reset to default (=manual) not installed or now-removed ones if requested
+	 if (InstalledOnly && (
+	     (pkg->CurrentVer == 0 && P.Mode != ModeInstall) ||
+	     (pkg->CurrentVer != 0 && P.Mode == ModeDelete)))
+	    newAuto = false;
+	 if (newAuto == false)
+	 {
+	    // The section is obsolete if it contains no other tag
+	    auto const count = section.Count();
+	    if (count < 2 ||
+		(count == 2 && section.Exists("Auto-Installed")) ||
+		(count == 3 && section.Exists("Auto-Installed") && section.Exists("Architecture")))
+	    {
+	       if(debug_autoremove)
+		  std::clog << "Drop obsolete section with " << count << " fields for " << APT::PrettyPkg(this, pkg) << std::endl;
+	       continue;
+	    }
+	 }
+
+	 if(debug_autoremove)
+	    std::clog << "Update existing AutoInstall to " << newAuto << " for " << APT::PrettyPkg(this, pkg) << std::endl;
+
+	 std::vector<pkgTagSection::Tag> rewrite;
+	 rewrite.push_back(pkgTagSection::Tag::Rewrite("Architecture", pkg.Arch()));
+	 rewrite.push_back(pkgTagSection::Tag::Rewrite("Auto-Installed", newAuto ? "1" : "0"));
+	 section.Write(OutFile, NULL, rewrite);
+	 if (OutFile.Write("\n", 1) == false)
+	    return false;
+	 pkgs_seen.insert(pkg.FullName());
+   }
+
+   // then write the ones we have not seen yet
+   for(pkgCache::PkgIterator pkg=Cache->PkgBegin(); !pkg.end(); ++pkg) {
+      StateCache const &P = PkgState[pkg->ID];
+      if(P.Flags & Flag::Auto) {
+	 if (pkgs_seen.find(pkg.FullName()) != pkgs_seen.end()) {
+	    if(debug_autoremove)
+	       std::clog << "Skipping already written " << APT::PrettyPkg(this, pkg) << std::endl;
+	    continue;
+	 }
+	 // skip not installed ones if requested
+	 if (InstalledOnly && (
+	     (pkg->CurrentVer == 0 && P.Mode != ModeInstall) ||
+	     (pkg->CurrentVer != 0 && P.Mode == ModeDelete)))
+	    continue;
+	 if(debug_autoremove)
+	    std::clog << "Writing new AutoInstall: " << APT::PrettyPkg(this, pkg) << std::endl;
+	 std::string stanza = "Package: ";
+	 stanza.append(pkg.Name())
+	      .append("\nArchitecture: ").append(pkg.Arch())
+	      .append("\nAuto-Installed: 1\n\n");
+	 if (OutFile.Write(stanza.c_str(), stanza.length()) == false)
+	    return false;
+      }
+   }
+   if (StateFile.Failed())
+   {
+      OutFile.OpFail();
+      return false;
+   }
+   if (OutFile.Close() == false)
+      return false;
+   chmod(state.c_str(), 0644);
+   return true;
+}
+									/*}}}*/
+// DepCache::CheckDep - Checks a single dependency			/*{{{*/
+// ---------------------------------------------------------------------
+/* This first checks the dependency against the main target package and
+   then walks along the package provides list and checks if each provides 
+   will be installed then checks the provides against the dep. Res will be 
+   set to the package which was used to satisfy the dep. */
+bool pkgDepCache::CheckDep(DepIterator const &Dep,int const Type,PkgIterator &Res)
+{
+   Res = Dep.TargetPkg();
+
+   /* Check simple depends. A depends -should- never self match but 
+      we allow it anyhow because dpkg does. Technically it is a packaging
+      bug. Conflicts may never self match */
+   if (Dep.IsIgnorable(Res) == false)
+   {
+      // Check the base package
+      if (Type == NowVersion)
+      {
+	 if (Res->CurrentVer != 0 && Dep.IsSatisfied(Res.CurrentVer()) == true)
+	    return true;
+      }
+      else if (Type == InstallVersion)
+      {
+	 if (PkgState[Res->ID].InstallVer != 0 &&
+	       Dep.IsSatisfied(PkgState[Res->ID].InstVerIter(*this)) == true)
+	    return true;
+      }
+      else if (Type == CandidateVersion)
+	 if (PkgState[Res->ID].CandidateVer != 0 &&
+	       Dep.IsSatisfied(PkgState[Res->ID].CandidateVerIter(*this)) == true)
+	    return true;
+   }
+
+   if (Dep->Type == Dep::Obsoletes)
+      return false;
+
+   // Check the providing packages
+   PrvIterator P = Dep.TargetPkg().ProvidesList();
+   for (; P.end() != true; ++P)
+   {
+      if (Dep.IsIgnorable(P) == true)
+	 continue;
+
+      // Check if the provides is a hit
+      if (Type == NowVersion)
+      {
+	 if (P.OwnerPkg().CurrentVer() != P.OwnerVer())
+	    continue;
+      }
+      else if (Type == InstallVersion)
+      {
+	 StateCache &State = PkgState[P.OwnerPkg()->ID];
+	 if (State.InstallVer != (Version *)P.OwnerVer())
+	    continue;
+      }
+      else if (Type == CandidateVersion)
+      {
+	 StateCache &State = PkgState[P.OwnerPkg()->ID];
+	 if (State.CandidateVer != (Version *)P.OwnerVer())
+	    continue;
+      }
+
+      // Compare the versions.
+      if (Dep.IsSatisfied(P) == true)
+      {
+	 Res = P.OwnerPkg();
+	 return true;
+      }
+   }
+
+   return false;
+}
+									/*}}}*/
+// DepCache::AddSizes - Add the packages sizes to the counters		/*{{{*/
+// ---------------------------------------------------------------------
+/* Call with Inverse = true to perform the inverse operation */
+void pkgDepCache::AddSizes(const PkgIterator &Pkg, bool const Inverse)
+{
+   StateCache &P = PkgState[Pkg->ID];
+   
+   if (Pkg->VersionList == 0)
+      return;
+   
+   if (Pkg.State() == pkgCache::PkgIterator::NeedsConfigure && 
+       P.Keep() == true)
+      return;
+   
+   // Compute the size data
+   if (P.NewInstall() == true)
+   {
+      if (Inverse == false) {
+	 iUsrSize += P.InstVerIter(*this)->InstalledSize;
+	 iDownloadSize += P.InstVerIter(*this)->Size;
+      } else {
+	 iUsrSize -= P.InstVerIter(*this)->InstalledSize;
+	 iDownloadSize -= P.InstVerIter(*this)->Size;
+      }
+      return;
+   }
+   
+   // Upgrading
+   if (Pkg->CurrentVer != 0 && 
+       (P.InstallVer != (Version *)Pkg.CurrentVer() || 
+	(P.iFlags & ReInstall) == ReInstall) && P.InstallVer != 0)
+   {
+      if (Inverse == false) {
+	 iUsrSize -= Pkg.CurrentVer()->InstalledSize;
+	 iUsrSize += P.InstVerIter(*this)->InstalledSize;
+	 iDownloadSize += P.InstVerIter(*this)->Size;
+      } else {
+	 iUsrSize -= P.InstVerIter(*this)->InstalledSize;
+	 iUsrSize += Pkg.CurrentVer()->InstalledSize;
+	 iDownloadSize -= P.InstVerIter(*this)->Size;
+      }
+      return;
+   }
+   
+   // Reinstall
+   if (Pkg.State() == pkgCache::PkgIterator::NeedsUnpack &&
+       P.Delete() == false)
+   {
+      if (Inverse == false)
+	 iDownloadSize += P.InstVerIter(*this)->Size;
+      else
+	 iDownloadSize -= P.InstVerIter(*this)->Size;
+      return;
+   }
+   
+   // Removing
+   if (Pkg->CurrentVer != 0 && P.InstallVer == 0)
+   {
+      if (Inverse == false)
+	 iUsrSize -= Pkg.CurrentVer()->InstalledSize;
+      else
+	 iUsrSize += Pkg.CurrentVer()->InstalledSize;
+      return;
+   }   
+}
+									/*}}}*/
+// DepCache::AddStates - Add the package to the state counter		/*{{{*/
+// ---------------------------------------------------------------------
+/* This routine is tricky to use, you must make sure that it is never
+   called twice for the same package. This means the Remove/Add section
+   should be as short as possible and not encompass any code that will
+   call Remove/Add itself. Remember, dependencies can be circular so
+   while processing a dep for Pkg it is possible that Add/Remove
+   will be called on Pkg */
+void pkgDepCache::AddStates(const PkgIterator &Pkg, bool const Invert)
+{
+   signed char const Add = (Invert == false) ? 1 : -1;
+   StateCache &State = PkgState[Pkg->ID];
+
+   // The Package is broken (either minimal dep or policy dep)
+   if ((State.DepState & DepInstMin) != DepInstMin)
+      iBrokenCount += Add;
+   if ((State.DepState & DepInstPolicy) != DepInstPolicy)
+      iPolicyBrokenCount += Add;
+
+   // Bad state
+   if (Pkg.State() != PkgIterator::NeedsNothing)
+      iBadCount += Add;
+
+   // Not installed
+   if (Pkg->CurrentVer == 0)
+   {
+      if (State.Mode == ModeDelete &&
+	  (State.iFlags & Purge) == Purge && Pkg.Purge() == false)
+	 iDelCount += Add;
+
+      if (State.Mode == ModeInstall)
+	 iInstCount += Add;
+      return;
+   }
+
+   // Installed, no upgrade
+   if (State.Status == 0)
+   {
+      if (State.Mode == ModeDelete)
+	 iDelCount += Add;
+      else
+	 if ((State.iFlags & ReInstall) == ReInstall)
+	    iInstCount += Add;
+      return;
+   }
+
+   // Alll 3 are possible
+   if (State.Mode == ModeDelete)
+      iDelCount += Add;
+   else if (State.Mode == ModeKeep)
+      iKeepCount += Add;
+   else if (State.Mode == ModeInstall)
+      iInstCount += Add;
+}
+									/*}}}*/
+// DepCache::BuildGroupOrs - Generate the Or group dep data		/*{{{*/
+// ---------------------------------------------------------------------
+/* The or group results are stored in the last item of the or group. This
+   allows easy detection of the state of a whole or'd group. */
+void pkgDepCache::BuildGroupOrs(VerIterator const &V)
+{
+   unsigned char Group = 0;
+   for (DepIterator D = V.DependsList(); D.end() != true; ++D)
+   {
+      // Build the dependency state.
+      unsigned char &State = DepState[D->ID];
+
+      /* Invert for Conflicts. We have to do this twice to get the
+         right sense for a conflicts group */
+      if (D.IsNegative() == true)
+	 State = ~State;
+
+      // Add to the group if we are within an or..
+      State &= 0x7;
+      Group |= State;
+      State |= Group << 3;
+      if ((D->CompareOp & Dep::Or) != Dep::Or)
+	 Group = 0;
+
+      // Invert for Conflicts
+      if (D.IsNegative() == true)
+	 State = ~State;
+   }
+}
+									/*}}}*/
+// DepCache::VersionState - Perform a pass over a dependency list	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to run over a dependency list and determine the dep
+   state of the list, filtering it through both a Min check and a Policy
+   check. The return result will have SetMin/SetPolicy low if a check
+   fails. It uses the DepState cache for it's computations. */
+unsigned char pkgDepCache::VersionState(DepIterator D, unsigned char const Check,
+				       unsigned char const SetMin,
+				       unsigned char const SetPolicy) const
+{
+   unsigned char Dep = 0xFF;
+   while (D.end() != true)
+   {
+      // the last or-dependency has the state of all previous or'ed
+      DepIterator Start, End;
+      D.GlobOr(Start, End);
+      // ignore if we are called with Dep{Install,…} or DepG{Install,…}
+      // the later would be more correct, but the first is what we get
+      unsigned char const State = DepState[End->ID] | (DepState[End->ID] >> 3);
+
+      // Minimum deps that must be satisfied to have a working package
+      if (Start.IsCritical() == true)
+      {
+	 if ((State & Check) != Check)
+	    return Dep &= ~(SetMin | SetPolicy);
+      }
+      // Policy deps that must be satisfied to install the package
+      else if (IsImportantDep(Start) == true &&
+	  (State & Check) != Check)
+	 Dep &= ~SetPolicy;
+   }
+   return Dep;
+}
+									/*}}}*/
+// DepCache::DependencyState - Compute the 3 results for a dep		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the main dependency computation bit. It computes the 3 main
+   results for a dependency: Now, Install and Candidate. Callers must
+   invert the result if dealing with conflicts. */
+unsigned char pkgDepCache::DependencyState(DepIterator const &D)
+{
+   unsigned char State = 0;
+
+   if (CheckDep(D,NowVersion) == true)
+      State |= DepNow;
+   if (CheckDep(D,InstallVersion) == true)
+      State |= DepInstall;
+   if (CheckDep(D,CandidateVersion) == true)
+      State |= DepCVer;
+
+   return State;
+}
+									/*}}}*/
+// DepCache::UpdateVerState - Compute the Dep member of the state	/*{{{*/
+// ---------------------------------------------------------------------
+/* This determines the combined dependency representation of a package
+   for its two states now and install. This is done by using the pre-generated
+   dependency information. */
+void pkgDepCache::UpdateVerState(PkgIterator const &Pkg)
+{   
+   // Empty deps are always true
+   StateCache &State = PkgState[Pkg->ID];
+   State.DepState = 0xFF;
+   
+   // Check the Current state
+   if (Pkg->CurrentVer != 0)
+   {
+      DepIterator D = Pkg.CurrentVer().DependsList();
+      State.DepState &= VersionState(D,DepNow,DepNowMin,DepNowPolicy);
+   }
+   
+   /* Check the candidate state. We do not compare against the whole as
+      a candidate state but check the candidate version against the 
+      install states */
+   if (State.CandidateVer != 0)
+   {
+      DepIterator D = State.CandidateVerIter(*this).DependsList();
+      State.DepState &= VersionState(D,DepInstall,DepCandMin,DepCandPolicy);
+   }
+   
+   // Check target state which can only be current or installed
+   if (State.InstallVer != 0)
+   {
+      DepIterator D = State.InstVerIter(*this).DependsList();
+      State.DepState &= VersionState(D,DepInstall,DepInstMin,DepInstPolicy);
+   }
+}
+									/*}}}*/
+// DepCache::Update - Figure out all the state information		/*{{{*/
+// ---------------------------------------------------------------------
+/* This will figure out the state of all the packages and all the 
+   dependencies based on the current policy. */
+void pkgDepCache::PerformDependencyPass(OpProgress * const Prog)
+{
+   iUsrSize = 0;
+   iDownloadSize = 0;
+   iInstCount = 0;
+   iDelCount = 0;
+   iKeepCount = 0;
+   iBrokenCount = 0;
+   iPolicyBrokenCount = 0;
+   iBadCount = 0;
+
+   int Done = 0;
+   for (PkgIterator I = PkgBegin(); I.end() != true; ++I, ++Done)
+   {
+      if (Prog != 0 && Done%20 == 0)
+	 Prog->Progress(Done);
+      for (VerIterator V = I.VersionList(); V.end() != true; ++V)
+      {
+	 unsigned char Group = 0;
+
+	 for (DepIterator D = V.DependsList(); D.end() != true; ++D)
+	 {
+	    // Build the dependency state.
+	    unsigned char &State = DepState[D->ID];
+	    State = DependencyState(D);
+
+	    // Add to the group if we are within an or..
+	    Group |= State;
+	    State |= Group << 3;
+	    if ((D->CompareOp & Dep::Or) != Dep::Or)
+	       Group = 0;
+
+	    // Invert for Conflicts
+	    if (D.IsNegative() == true)
+	       State = ~State;
+	 }
+      }
+
+      // Compute the package dependency state and size additions
+      AddSizes(I);
+      UpdateVerState(I);
+      AddStates(I);
+   }
+   if (Prog != 0)
+      Prog->Progress(Done);
+}
+void pkgDepCache::Update(OpProgress * const Prog)
+{
+   PerformDependencyPass(Prog);
+   readStateFile(Prog);
+}
+									/*}}}*/
+// DepCache::Update - Update the deps list of a package	   		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a helper for update that only does the dep portion of the scan. 
+   It is mainly meant to scan reverse dependencies. */
+void pkgDepCache::Update(DepIterator D)
+{
+   // Update the reverse deps
+   for (;D.end() != true; ++D)
+   {      
+      unsigned char &State = DepState[D->ID];
+      State = DependencyState(D);
+    
+      // Invert for Conflicts
+      if (D.IsNegative() == true)
+	 State = ~State;
+
+      RemoveStates(D.ParentPkg());
+      BuildGroupOrs(D.ParentVer());
+      UpdateVerState(D.ParentPkg());
+      AddStates(D.ParentPkg());
+   }
+}
+									/*}}}*/
+// DepCache::Update - Update the related deps of a package		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called whenever the state of a package changes. It updates
+   all cached dependencies related to this package. */
+void pkgDepCache::Update(PkgIterator const &Pkg)
+{   
+   // Recompute the dep of the package
+   RemoveStates(Pkg);
+   UpdateVerState(Pkg);
+   AddStates(Pkg);
+   
+   // Update the reverse deps
+   Update(Pkg.RevDependsList());
+
+   // Update the provides map for the current ver
+   auto const CurVer = Pkg.CurrentVer();
+   if (not CurVer.end())
+      for (PrvIterator P = CurVer.ProvidesList(); not P.end(); ++P)
+	 Update(P.ParentPkg().RevDependsList());
+
+   // Update the provides map for the candidate ver
+   auto const CandVer = PkgState[Pkg->ID].CandidateVerIter(*this);
+   if (not CandVer.end() && CandVer != CurVer)
+      for (PrvIterator P = CandVer.ProvidesList(); not P.end(); ++P)
+	 Update(P.ParentPkg().RevDependsList());
+}
+									/*}}}*/
+// DepCache::IsModeChangeOk - check if it is ok to change the mode	/*{{{*/
+// ---------------------------------------------------------------------
+/* this is used by all Mark methods on the very first line to check sanity
+   and prevents mode changes for packages on hold for example.
+   If you want to check Mode specific stuff you can use the virtual public
+   Is<Mode>Ok methods instead */
+static char const* PrintMode(char const mode)
+{
+	 switch (mode)
+	 {
+	 case pkgDepCache::ModeInstall: return "Install";
+	 case pkgDepCache::ModeKeep: return "Keep";
+	 case pkgDepCache::ModeDelete: return "Delete";
+	 case pkgDepCache::ModeGarbage: return "Garbage";
+	 default: return "UNKNOWN";
+	 }
+}
+static bool IsModeChangeOk(pkgDepCache &Cache, pkgDepCache::ModeList const mode, pkgCache::PkgIterator const &Pkg,
+			   unsigned long const Depth, bool const FromUser, bool const DebugMarker)
+{
+   // we are not trying too hard…
+   if (unlikely(Depth > 3000))
+      return false;
+
+   // general sanity
+   if (unlikely(Pkg.end() == true || Pkg->VersionList == 0))
+      return false;
+
+   // the user is always right
+   if (FromUser == true)
+      return true;
+
+   auto &P = Cache[Pkg];
+   // not changing the mode is obviously also fine as we might want to call
+   // e.g. MarkInstall multiple times with different arguments for the same package
+   if (P.Mode == mode)
+      return true;
+
+   // if previous state was set by user only user can reset it
+   if ((P.iFlags & pkgDepCache::Protected) == pkgDepCache::Protected)
+   {
+      if (unlikely(DebugMarker == true))
+	 std::clog << OutputInDepth(Depth) << "Ignore Mark" << PrintMode(mode)
+		   << " of " << APT::PrettyPkg(&Cache, Pkg) << " as its mode (" << PrintMode(P.Mode)
+		   << ") is protected" << std::endl;
+      return false;
+   }
+   // enforce dpkg holds
+   else if (mode != pkgDepCache::ModeKeep && Pkg->SelectedState == pkgCache::State::Hold &&
+	    _config->FindB("APT::Ignore-Hold",false) == false)
+   {
+      if (unlikely(DebugMarker == true))
+	 std::clog << OutputInDepth(Depth) << "Hold prevents Mark" << PrintMode(mode)
+		   << " of " << APT::PrettyPkg(&Cache, Pkg) << std::endl;
+      return false;
+   }
+   // Do not allow removals of essential packages not explicitly triggered by the user
+   else if (mode == pkgDepCache::ModeDelete && (Pkg->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential &&
+	    not _config->FindB("APT::Get::Allow-Solver-Remove-Essential", false))
+   {
+      if (unlikely(DebugMarker == true))
+	 std::clog << OutputInDepth(Depth) << "Essential prevents Mark" << PrintMode(mode)
+		   << " of " << APT::PrettyPkg(&Cache, Pkg) << std::endl;
+      return false;
+   }
+   // Do not allow removals of essential packages not explicitly triggered by the user
+   else if (mode == pkgDepCache::ModeDelete && (Pkg->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important &&
+	    not _config->FindB("APT::Get::Allow-Solver-Remove-Essential", false))
+   {
+      if (unlikely(DebugMarker == true))
+	 std::clog << OutputInDepth(Depth) << "Protected prevents Mark" << PrintMode(mode)
+		   << " of " << APT::PrettyPkg(&Cache, Pkg) << std::endl;
+      return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// DepCache::MarkKeep - Put the package in the keep state		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgDepCache::MarkKeep(PkgIterator const &Pkg, bool Soft, bool FromUser,
+                           unsigned long Depth)
+{
+   if (not IsModeChangeOk(*this, ModeKeep, Pkg, Depth, FromUser, DebugMarker))
+      return false;
+
+   /* Reject an attempt to keep a non-source broken installed package, those
+      must be upgraded */
+   if (Pkg.State() == PkgIterator::NeedsUnpack && 
+       Pkg.CurrentVer().Downloadable() == false)
+      return false;
+
+   /* We changed the soft state all the time so the UI is a bit nicer
+      to use */
+   StateCache &P = PkgState[Pkg->ID];
+
+   // Check that it is not already kept
+   if (P.Mode == ModeKeep)
+      return true;
+
+   if (Soft == true)
+      P.iFlags |= AutoKept;
+   else
+      P.iFlags &= ~AutoKept;
+
+   ActionGroup group(*this);
+
+#if 0 // resetting the autoflag here means we lose the 
+      // auto-mark information if a user selects a package for removal
+      // but changes  his mind then and sets it for keep again
+      // - this makes sense as default when all Garbage dependencies
+      //   are automatically marked for removal (as aptitude does).
+      //   setting a package for keep then makes it no longer autoinstalled
+      //   for all other use-case this action is rather surprising
+   if(FromUser && !P.Marked)
+     P.Flags &= ~Flag::Auto;
+#endif
+
+   if (DebugMarker == true)
+      std::clog << OutputInDepth(Depth) << "MarkKeep " << APT::PrettyPkg(this, Pkg) << " FU=" << FromUser << std::endl;
+
+   RemoveSizes(Pkg);
+   RemoveStates(Pkg);
+
+   P.Mode = ModeKeep;
+   if (Pkg->CurrentVer == 0)
+      P.InstallVer = 0;
+   else
+      P.InstallVer = Pkg.CurrentVer();
+
+   AddStates(Pkg);
+   Update(Pkg);
+   AddSizes(Pkg);
+
+   return true;
+}
+									/*}}}*/
+// DepCache::MarkDelete - Put the package in the delete state		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgDepCache::MarkDelete(PkgIterator const &Pkg, bool rPurge,
+                             unsigned long Depth, bool FromUser)
+{
+   if (not IsModeChangeOk(*this, ModeDelete, Pkg, Depth, FromUser, DebugMarker))
+      return false;
+
+   StateCache &P = PkgState[Pkg->ID];
+
+   // Check that it is not already marked for delete
+   if ((P.Mode == ModeDelete || P.InstallVer == 0) && 
+       (Pkg.Purge() == true || rPurge == false))
+      return true;
+
+   // check if we are allowed to remove the package
+   if (IsDeleteOk(Pkg,rPurge,Depth,FromUser) == false)
+      return false;
+
+   P.iFlags &= ~(AutoKept | Purge);
+   if (rPurge == true)
+      P.iFlags |= Purge;
+
+   ActionGroup group(*this);
+
+   if (FromUser == false)
+   {
+      VerIterator const PV = P.InstVerIter(*this);
+      if (PV.end() == false)
+      {
+	 // removed metapackages mark their dependencies as manual to prevent in "desktop depends browser, texteditor"
+	 // the removal of browser to suggest the removal of desktop and texteditor.
+	 // We ignore the auto-bit here as we can't deal with metapackage cascardes otherwise.
+	 // We do not check for or-groups here as we don't know which package takes care of
+	 // providing the feature the user likes e.g.:  browser1 | browser2 | browser3
+	 // Temporary removals are effected by this as well, which is bad, but unlikely in practice
+	 bool const PinNeverMarkAutoSection = (PV->Section != 0 && SectionInSubTree("APT::Never-MarkAuto-Sections", PV.Section()));
+	 if (PinNeverMarkAutoSection)
+	 {
+	    for (DepIterator D = PV.DependsList(); D.end() != true; ++D)
+	    {
+	       if (D.IsMultiArchImplicit() == true || D.IsNegative() == true || IsImportantDep(D) == false)
+		  continue;
+
+	       pkgCacheFile CacheFile(this);
+	       APT::VersionList verlist = APT::VersionList::FromDependency(CacheFile, D, APT::CacheSetHelper::INSTALLED);
+	       for (auto const &V : verlist)
+	       {
+		  PkgIterator const DP = V.ParentPkg();
+		  if(DebugAutoInstall == true)
+		     std::clog << OutputInDepth(Depth) << "Setting " << DP.FullName(false) << " NOT as auto-installed (direct "
+			<< D.DepType() << " of " << Pkg.FullName(false) << " which is in APT::Never-MarkAuto-Sections)" << std::endl;
+
+		  MarkAuto(DP, false);
+	       }
+	    }
+	 }
+      }
+   }
+
+   if (DebugMarker == true)
+      std::clog << OutputInDepth(Depth) << (rPurge ? "MarkPurge " : "MarkDelete ") << APT::PrettyPkg(this, Pkg) << " FU=" << FromUser << std::endl;
+
+   RemoveSizes(Pkg);
+   RemoveStates(Pkg);
+   
+   if (Pkg->CurrentVer == 0 && (Pkg.Purge() == true || rPurge == false))
+      P.Mode = ModeKeep;
+   else
+      P.Mode = ModeDelete;
+   P.InstallVer = 0;
+
+   AddStates(Pkg);   
+   Update(Pkg);
+   AddSizes(Pkg);
+
+   return true;
+}
+									/*}}}*/
+// DepCache::IsDeleteOk - check if it is ok to remove this package	/*{{{*/
+// ---------------------------------------------------------------------
+/* The default implementation tries to prevent deletion of install requests.
+   dpkg holds are enforced by the private IsModeChangeOk */
+bool pkgDepCache::IsDeleteOk(PkgIterator const &Pkg,bool rPurge,
+			      unsigned long Depth, bool FromUser)
+{
+   return IsDeleteOkProtectInstallRequests(Pkg, rPurge, Depth, FromUser);
+}
+bool pkgDepCache::IsDeleteOkProtectInstallRequests(PkgIterator const &Pkg,
+      bool const /*rPurge*/, unsigned long const Depth, bool const FromUser)
+{
+   if (FromUser == false && Pkg->CurrentVer == 0)
+   {
+      StateCache &P = PkgState[Pkg->ID];
+      if (P.InstallVer != 0 && P.Status == 2 && (P.Flags & Flag::Auto) != Flag::Auto)
+      {
+	 if (DebugMarker == true)
+	    std::clog << OutputInDepth(Depth) << "Manual install request prevents MarkDelete of " << APT::PrettyPkg(this, Pkg) << std::endl;
+	 return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+struct CompareProviders							/*{{{*/
+{
+   pkgDepCache const &Cache;
+   pkgCache::PkgIterator const Pkg;
+   explicit CompareProviders(pkgDepCache const &pCache, pkgCache::DepIterator const &Dep) : Cache{pCache}, Pkg{Dep.TargetPkg()} {}
+   bool operator() (pkgCache::VerIterator const &AV, pkgCache::VerIterator const &BV)
+   {
+      pkgCache::PkgIterator const A = AV.ParentPkg();
+      pkgCache::PkgIterator const B = BV.ParentPkg();
+      // Deal with protected first as if they don't work we usually have a problem
+      if (Cache[A].Protect() != Cache[B].Protect())
+	 return Cache[A].Protect();
+      // Prefer MA:same packages if other architectures for it are installed
+      if ((AV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same ||
+	  (BV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+      {
+	 bool instA = false;
+	 if ((AV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+	 {
+	    pkgCache::GrpIterator Grp = A.Group();
+	    for (pkgCache::PkgIterator P = Grp.PackageList(); P.end() == false; P = Grp.NextPkg(P))
+	       if (P->CurrentVer != 0)
+	       {
+		  instA = true;
+		  break;
+	       }
+	 }
+	 bool instB = false;
+	 if ((BV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+	 {
+	    pkgCache::GrpIterator Grp = B.Group();
+	    for (pkgCache::PkgIterator P = Grp.PackageList(); P.end() == false; P = Grp.NextPkg(P))
+	    {
+	       if (P->CurrentVer != 0)
+	       {
+		  instB = true;
+		  break;
+	       }
+	    }
+	 }
+	 if (instA != instB)
+	    return instA;
+      }
+      if ((A->CurrentVer == 0 || B->CurrentVer == 0) && A->CurrentVer != B->CurrentVer)
+	 return A->CurrentVer != 0;
+      // Prefer packages in the same group as the target; e.g. foo:i386, foo:amd64
+      if (A->Group != B->Group)
+      {
+	 if (A->Group == Pkg->Group && B->Group != Pkg->Group)
+	    return true;
+	 else if (B->Group == Pkg->Group && A->Group != Pkg->Group)
+	    return false;
+      }
+      // we like essentials
+      if ((A->Flags & pkgCache::Flag::Essential) != (B->Flags & pkgCache::Flag::Essential))
+      {
+	 if ((A->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+	    return true;
+	 else if ((B->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+	    return false;
+      }
+      if ((A->Flags & pkgCache::Flag::Important) != (B->Flags & pkgCache::Flag::Important))
+      {
+	 if ((A->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
+	    return true;
+	 else if ((B->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
+	    return false;
+      }
+      // prefer native architecture
+      if (strcmp(A.Arch(), B.Arch()) != 0)
+      {
+	 if (strcmp(A.Arch(), A.Cache()->NativeArch()) == 0)
+	    return true;
+	 else if (strcmp(B.Arch(), B.Cache()->NativeArch()) == 0)
+	    return false;
+	 std::vector<std::string> archs = APT::Configuration::getArchitectures();
+	 for (std::vector<std::string>::const_iterator a = archs.begin(); a != archs.end(); ++a)
+	    if (*a == A.Arch())
+	       return true;
+	    else if (*a == B.Arch())
+	       return false;
+      }
+      // higher priority seems like a good idea
+      if (AV->Priority != BV->Priority)
+	 return AV->Priority < BV->Priority;
+      // unable to decide…
+      return A->ID > B->ID;
+   }
+};
+									/*}}}*/
+bool pkgDepCache::MarkInstall_StateChange(pkgCache::PkgIterator const &Pkg, bool AutoInst, bool FromUser) /*{{{*/
+{
+   bool AlwaysMarkAsAuto = _config->FindB("APT::Get::Mark-Auto", false) == true;
+   auto &P = (*this)[Pkg];
+   if (P.Protect() && P.InstallVer == P.CandidateVer)
+      return true;
+
+   P.iFlags &= ~pkgDepCache::AutoKept;
+
+   /* Target the candidate version and remove the autoflag. We reset the
+      autoflag below if this was called recursively. Otherwise the user
+      should have the ability to de-auto a package by changing its state */
+   RemoveSizes(Pkg);
+   RemoveStates(Pkg);
+
+   P.Mode = pkgDepCache::ModeInstall;
+   P.InstallVer = P.CandidateVer;
+
+   if(FromUser && !AlwaysMarkAsAuto)
+     {
+       // Set it to manual if it's a new install or already installed,
+       // but only if its not marked by the autoremover (aptitude depend on this behavior)
+       // or if we do automatic installation (aptitude never does it)
+       if(P.Status == 2 || (Pkg->CurrentVer != 0 && (AutoInst == true || P.Marked == false)))
+	 P.Flags &= ~pkgCache::Flag::Auto;
+     }
+   else
+     {
+       // Set it to auto if this is a new install.
+       if(P.Status == 2)
+	 P.Flags |= pkgCache::Flag::Auto;
+     }
+   if (P.CandidateVer == (pkgCache::Version *)Pkg.CurrentVer())
+      P.Mode = pkgDepCache::ModeKeep;
+
+   AddStates(Pkg);
+   Update(Pkg);
+   AddSizes(Pkg);
+   return true;
+}
+									/*}}}*/
+static bool MarkInstall_DiscardCandidate(pkgDepCache &Cache, pkgCache::PkgIterator const &Pkg) /*{{{*/
+{
+   auto &State = Cache[Pkg];
+   State.CandidateVer = State.InstallVer;
+   auto const oldStatus = State.Status;
+   State.Update(Pkg, Cache);
+   State.Status = oldStatus;
+   return true;
+}
+									/*}}}*/
+bool pkgDepCache::MarkInstall_DiscardInstall(pkgCache::PkgIterator const &Pkg) /*{{{*/
+{
+   StateCache &State = PkgState[Pkg->ID];
+   if (State.Mode == ModeKeep && State.InstallVer == State.CandidateVer && State.CandidateVer == Pkg.CurrentVer())
+      return true;
+   RemoveSizes(Pkg);
+   RemoveStates(Pkg);
+   if (Pkg->CurrentVer != 0)
+      State.InstallVer = Pkg.CurrentVer();
+   else
+      State.InstallVer = nullptr;
+   State.Mode = ModeKeep;
+   AddStates(Pkg);
+   Update(Pkg);
+   AddSizes(Pkg);
+   return MarkInstall_DiscardCandidate(*this, Pkg);
+}
+									/*}}}*/
+static bool MarkInstall_CollectDependencies(pkgDepCache const &Cache, pkgCache::VerIterator const &PV, std::vector<pkgCache::DepIterator> &toInstall, std::vector<pkgCache::DepIterator> &toRemove) /*{{{*/
+{
+   auto const propagateProtected = Cache[PV.ParentPkg()].Protect();
+   for (auto Dep = PV.DependsList(); not Dep.end();)
+   {
+      auto const Start = Dep;
+      // check if an installed package satisfies the dependency (and get the extend of the or-group)
+      bool foundSolution = false;
+      for (bool LastOR = true; not Dep.end() && LastOR; ++Dep)
+      {
+	 LastOR = (Dep->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or;
+	 if ((Cache[Dep] & pkgDepCache::DepInstall) == pkgDepCache::DepInstall)
+	    foundSolution = true;
+      }
+      if (foundSolution && not propagateProtected)
+	 continue;
+
+      /* Check if this dep should be consider for install.
+         (Pre-)Depends, Conflicts and Breaks for sure.
+         Recommends & Suggests depending on configuration */
+      if (not Cache.IsImportantDep(Start))
+	 continue;
+
+      if (Start.IsNegative())
+      {
+	 if (Start->Type != pkgCache::Dep::Obsoletes)
+	    toRemove.push_back(Start);
+      }
+      else
+	 toInstall.push_back(Start);
+   }
+   return true;
+}
+									/*}}}*/
+static APT::VersionVector getAllPossibleSolutions(pkgDepCache &Cache, pkgCache::DepIterator Start, pkgCache::DepIterator const &End, APT::CacheSetHelper::VerSelector const selector, bool const sorted) /*{{{*/
+{
+   pkgCacheFile CacheFile{&Cache};
+   APT::VersionVector toUpgrade, toNewInstall;
+   do
+   {
+      APT::VersionVector verlist = APT::VersionVector::FromDependency(CacheFile, Start, selector);
+      if (not sorted)
+      {
+	 std::move(verlist.begin(), verlist.end(), std::back_inserter(toUpgrade));
+	 continue;
+      }
+      std::sort(verlist.begin(), verlist.end(), CompareProviders{Cache, Start});
+      for (auto &&Ver : verlist)
+      {
+	 auto P = Ver.ParentPkg();
+	 if (P->CurrentVer != 0)
+	    toUpgrade.emplace_back(std::move(Ver));
+	 else
+	    toNewInstall.emplace_back(std::move(Ver));
+      }
+   } while (Start++ != End);
+   if (toUpgrade.empty())
+      toUpgrade = std::move(toNewInstall);
+   else
+      std::move(toNewInstall.begin(), toNewInstall.end(), std::back_inserter(toUpgrade));
+
+   if (not sorted)
+      std::sort(toUpgrade.begin(), toUpgrade.end(), [](pkgCache::VerIterator const &A, pkgCache::VerIterator const &B) { return A->ID < B->ID; });
+   toUpgrade.erase(std::unique(toUpgrade.begin(), toUpgrade.end()), toUpgrade.end());
+
+   if (not End.IsNegative())
+      toUpgrade.erase(std::remove_if(toUpgrade.begin(), toUpgrade.end(), [&Cache](pkgCache::VerIterator const &V) {
+			 auto const P = V.ParentPkg();
+			 auto const &State = Cache[P];
+			 return State.Protect() && (State.Delete() || (State.Keep() && P->CurrentVer == 0));
+		      }),
+		      toUpgrade.end());
+
+   return toUpgrade;
+}
+									/*}}}*/
+static bool MarkInstall_MarkDeleteForNotUpgradeable(pkgDepCache &Cache, bool const DebugAutoInstall, pkgCache::VerIterator const &PV, unsigned long const Depth, pkgCache::PkgIterator const &Pkg, bool const propagateProtected, APT::PackageVector &delayedRemove)/*{{{*/
+{
+   auto &State = Cache[Pkg];
+   if (not propagateProtected)
+   {
+      if (State.Delete())
+	 return true;
+      if(DebugAutoInstall)
+	 std::clog << OutputInDepth(Depth) << " Delayed Removing: " << Pkg.FullName() << " as upgrade is not an option for " << PV.ParentPkg().FullName() << " (" << PV.VerStr() << ")\n";
+      if (not IsModeChangeOk(Cache, pkgDepCache::ModeDelete, Pkg, Depth, false, DebugAutoInstall) ||
+	  not Cache.IsDeleteOk(Pkg, false, Depth, false))
+	 return false;
+      delayedRemove.push_back(Pkg);
+      return true;
+   }
+
+   if (not State.Delete())
+   {
+      if(DebugAutoInstall)
+	 std::clog << OutputInDepth(Depth) << " Removing: " << Pkg.FullName() << " as upgrade is not an option for " << PV.ParentPkg().FullName() << " (" << PV.VerStr() << ")\n";
+      if (not Cache.MarkDelete(Pkg, false, Depth + 1, false))
+	 return false;
+   }
+   MarkInstall_DiscardCandidate(Cache, Pkg);
+   Cache.MarkProtected(Pkg);
+   return true;
+}
+									/*}}}*/
+static bool MarkInstall_RemoveConflictsIfNotUpgradeable(pkgDepCache &Cache, bool const DebugAutoInstall, pkgCache::VerIterator const &PV, unsigned long Depth, std::vector<pkgCache::DepIterator> &toRemove, APT::PackageVector &toUpgrade, APT::PackageVector &delayedRemove, bool const propagateProtected, bool const FromUser) /*{{{*/
+{
+   /* Negative dependencies have no or-group
+      If the candidate is effected try to keep current and discard candidate
+      If the current is effected try upgrading to candidate or remove it */
+   bool failedToRemoveSomething = false;
+   APT::PackageVector badCandidate;
+   for (auto const &D : toRemove)
+   {
+      for (auto const &Ver : getAllPossibleSolutions(Cache, D, D, APT::CacheSetHelper::CANDIDATE, true))
+      {
+	 auto const Pkg = Ver.ParentPkg();
+	 auto &State = Cache[Pkg];
+	 if (State.CandidateVer != Ver)
+	    continue;
+	 if (Pkg.CurrentVer() != Ver)
+	 {
+	    if (State.Install() && not Cache.MarkKeep(Pkg, false, false, Depth))
+	    {
+	       failedToRemoveSomething = true;
+	       if (not propagateProtected && not FromUser)
+		  break;
+	    }
+	    else if (propagateProtected)
+	    {
+	       MarkInstall_DiscardCandidate(Cache, Pkg);
+	       if (Pkg->CurrentVer == 0)
+		  Cache.MarkProtected(Pkg);
+	    }
+	    else
+	       badCandidate.push_back(Pkg);
+	 }
+	 else if (not MarkInstall_MarkDeleteForNotUpgradeable(Cache, DebugAutoInstall, PV, Depth, Pkg, propagateProtected, delayedRemove))
+	 {
+	    failedToRemoveSomething = true;
+	    if (not propagateProtected && not FromUser)
+	       break;
+	 }
+      }
+      if (failedToRemoveSomething && not propagateProtected && not FromUser)
+	 break;
+      for (auto const &Ver : getAllPossibleSolutions(Cache, D, D, APT::CacheSetHelper::INSTALLED, true))
+      {
+	 auto const Pkg = Ver.ParentPkg();
+	 auto &State = Cache[Pkg];
+	 if (State.CandidateVer != Ver && State.CandidateVer != nullptr &&
+	     std::find(badCandidate.cbegin(), badCandidate.cend(), Pkg) == badCandidate.end())
+	    toUpgrade.push_back(Pkg);
+	 else if (State.CandidateVer == Pkg.CurrentVer())
+	    ; // already done in the first loop above
+	 else if (not MarkInstall_MarkDeleteForNotUpgradeable(Cache, DebugAutoInstall, PV, Depth, Pkg, propagateProtected, delayedRemove))
+	 {
+	    failedToRemoveSomething = true;
+	    if (not propagateProtected && not FromUser)
+	       break;
+	 }
+      }
+      if (failedToRemoveSomething && not propagateProtected && not FromUser)
+	 break;
+   }
+   toRemove.clear();
+   return not failedToRemoveSomething;
+}
+									/*}}}*/
+static bool MarkInstall_CollectReverseDepends(pkgDepCache &Cache, bool const DebugAutoInstall, pkgCache::VerIterator const &PV, unsigned long Depth, APT::PackageVector &toUpgrade) /*{{{*/
+{
+   auto CurrentVer = PV.ParentPkg().CurrentVer();
+   if (CurrentVer.end())
+      return true;
+   for (pkgCache::DepIterator D = PV.ParentPkg().RevDependsList(); D.end() == false; ++D)
+   {
+      auto ParentPkg = D.ParentPkg();
+      // Skip non-installed versions and packages already marked for upgrade
+      if (ParentPkg.CurrentVer() != D.ParentVer() || Cache[ParentPkg].Install())
+	 continue;
+      // We only handle important positive dependencies, RemoveConflictsIfNotUpgradeable handles negative
+      if (not Cache.IsImportantDep(D) || D.IsNegative())
+	 continue;
+      // The dependency was previously not satisfied (e.g. part of an or group) or will be satisfied, so it's OK
+      if (not D.IsSatisfied(CurrentVer) || D.IsSatisfied(PV))
+	 continue;
+      if (std::find(toUpgrade.begin(), toUpgrade.end(), ParentPkg) != toUpgrade.end())
+	 continue;
+
+      if (DebugAutoInstall)
+	 std::clog << OutputInDepth(Depth) << " Upgrading: " << APT::PrettyPkg(&Cache, ParentPkg) << " due to " << APT::PrettyDep(&Cache, D) << "\n";
+
+      toUpgrade.push_back(ParentPkg);
+   }
+   return true;
+}
+									/*}}}*/
+static bool MarkInstall_UpgradeOrRemoveConflicts(pkgDepCache &Cache, bool const DebugAutoInstall, unsigned long Depth, bool const ForceImportantDeps, APT::PackageVector &toUpgrade, bool const propagateProtected, bool const FromUser) /*{{{*/
+{
+   bool failedToRemoveSomething = false;
+   for (auto const &InstPkg : toUpgrade)
+      if (not Cache[InstPkg].Install() && not Cache.MarkInstall(InstPkg, true, Depth + 1, false, ForceImportantDeps))
+      {
+	 if (DebugAutoInstall)
+	    std::clog << OutputInDepth(Depth) << " Removing: " << InstPkg.FullName() << " as upgrade is not possible\n";
+	 if (not Cache.MarkDelete(InstPkg, false, Depth + 1, false))
+	 {
+	    failedToRemoveSomething = true;
+	    if (not propagateProtected && not FromUser)
+	       break;
+	 }
+	 else if (propagateProtected)
+	    Cache.MarkProtected(InstPkg);
+      }
+   toUpgrade.clear();
+   return not failedToRemoveSomething;
+}
+									/*}}}*/
+static bool MarkInstall_UpgradeOtherBinaries(pkgDepCache &Cache, bool const DebugAutoInstall, unsigned long Depth, bool const ForceImportantDeps, pkgCache::PkgIterator Pkg, pkgCache::VerIterator Ver) /*{{{*/
+{
+   APT::PackageSet toUpgrade;
+
+   if (not _config->FindB("APT::Get::Upgrade-By-Source-Package", true))
+      return true;
+
+   auto SrcGrp = Cache.FindGrp(Ver.SourcePkgName());
+   for (auto OtherBinary = SrcGrp.VersionsInSource(); not OtherBinary.end(); OtherBinary = OtherBinary.NextInSource())
+   {
+      auto OtherPkg = OtherBinary.ParentPkg();
+      auto OtherState = Cache[OtherPkg];
+      if (OtherPkg == Pkg)
+	 continue;
+      // Package is not installed or at right version, don't need to upgrade
+      if (OtherPkg->CurrentVer == 0 || OtherPkg.CurrentVer() == OtherBinary)
+	 continue;
+      // Package is to be installed at right version, don't need to upgrade
+      if (OtherState.Install() && OtherState.InstallVer == OtherBinary)
+	 continue;
+      // Package has a different source version than us, so it's not relevant
+      if (strcmp(OtherBinary.SourceVerStr(), Ver.SourceVerStr()) != 0 || OtherState.CandidateVer != OtherBinary)
+	 continue;
+      if (DebugAutoInstall)
+	 std::clog << OutputInDepth(Depth) << "Upgrading " << APT::PrettyPkg(&Cache, OtherPkg) << " due to " << Pkg.FullName() << '\n';
+
+      toUpgrade.insert(OtherPkg);
+   }
+   for (auto &OtherPkg : toUpgrade)
+      Cache.MarkInstall(OtherPkg, false, Depth + 1, false, ForceImportantDeps);
+   for (auto &OtherPkg : toUpgrade)
+      Cache.MarkInstall(OtherPkg, true, Depth + 1, false, ForceImportantDeps);
+   return true;
+}
+									/*}}}*/
+static bool MarkInstall_InstallDependencies(pkgDepCache &Cache, bool const DebugAutoInstall, bool const DebugMarker, pkgCache::PkgIterator const &Pkg, unsigned long Depth, bool const ForceImportantDeps, std::vector<pkgCache::DepIterator> &toInstall, APT::PackageVector *const toMoveAuto, bool const propagateProtected, bool const FromUser) /*{{{*/
+{
+   auto const IsSatisfiedByInstalled = [&](auto &D) { return (Cache[pkgCache::DepIterator{Cache, &D}] & pkgDepCache::DepInstall) == pkgDepCache::DepInstall; };
+   bool failedToInstallSomething = false;
+   for (auto &&Dep : toInstall)
+   {
+      auto const Copy = Dep;
+      pkgCache::DepIterator Start, End;
+      Dep.GlobOr(Start, End);
+      bool foundSolution = std::any_of(Start, Dep, IsSatisfiedByInstalled);
+      if (foundSolution && not propagateProtected)
+	 continue;
+      bool const IsCriticalDep = Start.IsCritical();
+      if (foundSolution)
+      {
+	 // try propagating protected to this satisfied dependency
+	 if (not IsCriticalDep)
+	    continue;
+	 auto const possibleSolutions = getAllPossibleSolutions(Cache, Start, End, APT::CacheSetHelper::CANDANDINST, false);
+	 if (possibleSolutions.size() != 1)
+	    continue;
+	 auto const InstPkg = possibleSolutions.begin().ParentPkg();
+	 if (Cache[InstPkg].Protect())
+	    continue;
+	 Cache.MarkProtected(InstPkg);
+	 if (not Cache.MarkInstall(InstPkg, true, Depth + 1, false, ForceImportantDeps))
+	    failedToInstallSomething = true;
+	 continue;
+      }
+
+      /* Check if any ImportantDep() (but not Critical) were added
+       * since we installed the package.  Also check for deps that
+       * were satisfied in the past: for instance, if a version
+       * restriction in a Recommends was tightened, upgrading the
+       * package should follow that Recommends rather than causing the
+       * dependency to be removed. (bug #470115)
+       */
+      if (Pkg->CurrentVer != 0 && not ForceImportantDeps && not IsCriticalDep)
+      {
+	 bool isNewImportantDep = true;
+	 bool isPreviouslySatisfiedImportantDep = false;
+	 for (pkgCache::DepIterator D = Pkg.CurrentVer().DependsList(); D.end() != true; ++D)
+	 {
+	    //FIXME: Should we handle or-group better here?
+	    // We do not check if the package we look for is part of the same or-group
+	    // we might find while searching, but could that really be a problem?
+	    if (D.IsCritical() || not Cache.IsImportantDep(D) ||
+		Start.TargetPkg() != D.TargetPkg())
+	       continue;
+
+	    isNewImportantDep = false;
+
+	    while ((D->CompareOp & pkgCache::Dep::Or) != 0)
+	       ++D;
+
+	    isPreviouslySatisfiedImportantDep = ((Cache[D] & pkgDepCache::DepGNow) != 0);
+	    if (isPreviouslySatisfiedImportantDep)
+	       break;
+	 }
+
+	 if (isNewImportantDep)
+	 {
+	    if (DebugAutoInstall)
+	       std::clog << OutputInDepth(Depth) << "new important dependency: "
+			 << Start.TargetPkg().FullName() << '\n';
+	 }
+	 else if (isPreviouslySatisfiedImportantDep)
+	 {
+	    if (DebugAutoInstall)
+	       std::clog << OutputInDepth(Depth) << "previously satisfied important dependency on "
+			 << Start.TargetPkg().FullName() << '\n';
+	 }
+	 else
+	 {
+	    if (DebugAutoInstall)
+	       std::clog << OutputInDepth(Depth) << "ignore old unsatisfied important dependency on "
+			 << Start.TargetPkg().FullName() << '\n';
+	    continue;
+	 }
+      }
+
+      auto const possibleSolutions = getAllPossibleSolutions(Cache, Start, End, APT::CacheSetHelper::CANDIDATE, true);
+      for (auto const &InstVer : possibleSolutions)
+      {
+	 auto const InstPkg = InstVer.ParentPkg();
+	 if (Cache[InstPkg].CandidateVer != InstVer)
+	    continue;
+	 if (DebugAutoInstall)
+	    std::clog << OutputInDepth(Depth) << "Installing " << InstPkg.FullName()
+		      << " as " << End.DepType() << " of " << Pkg.FullName() << '\n';
+	 if (propagateProtected && IsCriticalDep && possibleSolutions.size() == 1)
+	 {
+	    if (not Cache.MarkInstall(InstPkg, false, Depth + 1, false, ForceImportantDeps))
+	       continue;
+	    Cache.MarkProtected(InstPkg);
+	 }
+	 if (not Cache.MarkInstall(InstPkg, true, Depth + 1, false, ForceImportantDeps))
+	    continue;
+
+	 if (toMoveAuto != nullptr && InstPkg->CurrentVer == 0)
+	    toMoveAuto->push_back(InstPkg);
+
+	 foundSolution = true;
+	 break;
+      }
+      if (DebugMarker && not foundSolution)
+	 std::clog << OutputInDepth(Depth+1) << APT::PrettyDep(&Cache, Copy) << " can't be satisfied! (dep)\n";
+      if (not foundSolution && IsCriticalDep)
+      {
+	 failedToInstallSomething = true;
+	 if (not propagateProtected && not FromUser)
+	    break;
+      }
+   }
+   toInstall.clear();
+   return not failedToInstallSomething;
+}
+									/*}}}*/
+// DepCache::MarkInstall - Put the package in the install state		/*{{{*/
+bool pkgDepCache::MarkInstall(PkgIterator const &Pkg, bool AutoInst,
+			      unsigned long Depth, bool FromUser,
+			      bool ForceImportantDeps)
+{
+   StateCache &P = PkgState[Pkg->ID];
+   if (P.Protect() && P.Keep() && P.CandidateVer != nullptr && P.CandidateVer == Pkg.CurrentVer())
+      ; // we are here to mark our dependencies as protected, no state is changed
+   else if (not IsModeChangeOk(*this, ModeInstall, Pkg, Depth, FromUser, DebugMarker))
+      return false;
+
+
+   // See if there is even any possible installation candidate
+   if (P.CandidateVer == 0)
+      return false;
+
+   // Check that it is not already marked for install and that it can be installed
+   if (not P.Protect() && not P.InstPolicyBroken() && not P.InstBroken())
+   {
+      if (P.CandidateVer == Pkg.CurrentVer())
+      {
+	 if (P.InstallVer == 0)
+	    return MarkKeep(Pkg, false, FromUser, Depth + 1);
+	 return true;
+      }
+      else if (P.Mode == ModeInstall)
+	 return true;
+   }
+
+   // check if we are allowed to install the package
+   if (not IsInstallOk(Pkg, AutoInst, Depth, FromUser))
+      return false;
+
+   ActionGroup group(*this);
+   if (FromUser && not MarkInstall_StateChange(Pkg, AutoInst, FromUser))
+      return false;
+
+   bool const AutoSolve = AutoInst && _config->Find("APT::Solver", "internal") == "internal";
+   bool const failEarly = not P.Protect() && not FromUser;
+   bool hasFailed = false;
+
+   std::vector<pkgCache::DepIterator> toInstall, toRemove;
+   APT::PackageVector toUpgrade, delayedRemove;
+   if (AutoSolve)
+   {
+      VerIterator const PV = P.CandidateVerIter(*this);
+      if (unlikely(PV.end()))
+	 return false;
+      if (not MarkInstall_CollectDependencies(*this, PV, toInstall, toRemove))
+	 return false;
+
+      if (not MarkInstall_RemoveConflictsIfNotUpgradeable(*this, DebugAutoInstall, PV, Depth, toRemove, toUpgrade, delayedRemove, P.Protect(), FromUser))
+      {
+	 if (failEarly)
+	    return false;
+	 hasFailed = true;
+      }
+      if (not MarkInstall_CollectReverseDepends(*this, DebugAutoInstall, PV, Depth, toUpgrade))
+      {
+	 if (failEarly)
+	    return false;
+	 hasFailed = true;
+      }
+   }
+
+   if (not FromUser && not MarkInstall_StateChange(Pkg, AutoInst, FromUser))
+      return false;
+
+   if (not AutoSolve)
+      return not hasFailed;
+
+   if (DebugMarker)
+      std::clog << OutputInDepth(Depth) << "MarkInstall " << APT::PrettyPkg(this, Pkg) << " FU=" << FromUser << '\n';
+
+   class ScopedProtected
+   {
+      pkgDepCache::StateCache &P;
+      bool const already;
+
+      public:
+      ScopedProtected(pkgDepCache::StateCache &p) : P{p}, already{P.Protect()}
+      {
+	 if (not already)
+	    P.iFlags |= Protected;
+      }
+      ~ScopedProtected()
+      {
+	 if (not already)
+	    P.iFlags &= (~Protected);
+      }
+      operator bool() noexcept { return already; }
+   } propagateProtected{PkgState[Pkg->ID]};
+
+   if (not MarkInstall_UpgradeOtherBinaries(*this, DebugAutoInstall, Depth, ForceImportantDeps, Pkg, P.CandidateVerIter(*this)))
+      return false;
+   if (not MarkInstall_UpgradeOrRemoveConflicts(*this, DebugAutoInstall, Depth, ForceImportantDeps, toUpgrade, propagateProtected, FromUser))
+   {
+      if (failEarly)
+      {
+	 MarkInstall_DiscardInstall(Pkg);
+	 return false;
+      }
+      hasFailed = true;
+   }
+
+   bool const MoveAutoBitToDependencies = [&]() {
+      VerIterator const PV = P.InstVerIter(*this);
+      if (unlikely(PV.end()))
+	 return false;
+      if (PV->Section == 0 || (P.Flags & Flag::Auto) == Flag::Auto)
+	 return false;
+      VerIterator const CurVer = Pkg.CurrentVer();
+      if (not CurVer.end() && CurVer->Section != 0 && strcmp(CurVer.Section(), PV.Section()) != 0)
+      {
+	 bool const CurVerInMoveSection = SectionInSubTree("APT::Move-Autobit-Sections", CurVer.Section());
+	 bool const InstVerInMoveSection = SectionInSubTree("APT::Move-Autobit-Sections", PV.Section());
+	 return (not CurVerInMoveSection && InstVerInMoveSection);
+      }
+      return false;
+   }();
+
+   APT::PackageVector toMoveAuto;
+   if (not MarkInstall_InstallDependencies(*this, DebugAutoInstall, DebugMarker, Pkg, Depth, ForceImportantDeps, toInstall,
+					   MoveAutoBitToDependencies ? &toMoveAuto : nullptr, propagateProtected, FromUser))
+   {
+      if (failEarly)
+      {
+	 MarkInstall_DiscardInstall(Pkg);
+	 return false;
+      }
+      hasFailed = true;
+   }
+
+   for (auto const &R : delayedRemove)
+   {
+      if (not MarkDelete(R, false, Depth, false))
+      {
+	 if (failEarly)
+	 {
+	    MarkInstall_DiscardInstall(Pkg);
+	    return false;
+	 }
+	 hasFailed = true;
+      }
+   }
+
+   if (MoveAutoBitToDependencies)
+   {
+      if (DebugAutoInstall)
+	 std::clog << OutputInDepth(Depth) << "Setting " << Pkg.FullName(false) << " as auto-installed, moving manual to its dependencies" << std::endl;
+      MarkAuto(Pkg, true);
+      for (auto const &InstPkg : toMoveAuto)
+      {
+	 if (DebugAutoInstall)
+	    std::clog << OutputInDepth(Depth) << "Setting " << InstPkg.FullName(false) << " NOT as auto-installed (dependency"
+		      << " of " << Pkg.FullName(false) << " which is manual and in APT::Move-Autobit-Sections)\n";
+	 MarkAuto(InstPkg, false);
+      }
+   }
+   return not hasFailed;
+}
+									/*}}}*/
+// DepCache::IsInstallOk - check if it is ok to install this package	/*{{{*/
+// ---------------------------------------------------------------------
+/* The default implementation checks if the installation of an M-A:same
+   package would lead us into a version-screw and if so forbids it.
+   dpkg holds are enforced by the private IsModeChangeOk */
+bool pkgDepCache::IsInstallOk(PkgIterator const &Pkg,bool AutoInst,
+			      unsigned long Depth, bool FromUser)
+{
+   return IsInstallOkMultiArchSameVersionSynced(Pkg,AutoInst, Depth, FromUser) &&
+      IsInstallOkDependenciesSatisfiableByCandidates(Pkg,AutoInst, Depth, FromUser);
+}
+bool pkgDepCache::IsInstallOkMultiArchSameVersionSynced(PkgIterator const &Pkg,
+      bool const /*AutoInst*/, unsigned long const Depth, bool const FromUser)
+{
+   if (FromUser == true) // as always: user is always right
+      return true;
+
+   // if we have checked before and it was okay, it will still be okay
+   if (PkgState[Pkg->ID].Mode == ModeInstall &&
+	 PkgState[Pkg->ID].InstallVer == PkgState[Pkg->ID].CandidateVer)
+      return true;
+
+   // ignore packages with none-M-A:same candidates
+   VerIterator const CandVer = PkgState[Pkg->ID].CandidateVerIter(*this);
+   if (unlikely(CandVer.end() == true) || CandVer == Pkg.CurrentVer() ||
+	 (CandVer->MultiArch & pkgCache::Version::Same) != pkgCache::Version::Same)
+      return true;
+
+   GrpIterator const Grp = Pkg.Group();
+   for (PkgIterator P = Grp.PackageList(); P.end() == false; P = Grp.NextPkg(P))
+   {
+      // not installed or self-check: fine by definition
+      if (P->CurrentVer == 0 || P == Pkg)
+	 continue;
+
+      // not having a candidate or being in sync
+      // (simple string-compare as stuff like '1' == '0:1-0' can't happen here)
+      VerIterator CV = PkgState[P->ID].CandidateVerIter(*this);
+      if (CV.end() == true || strcmp(CandVer.VerStr(), CV.VerStr()) == 0)
+	 continue;
+
+      // packages losing M-A:same can be out-of-sync
+      if ((CV->MultiArch & pkgCache::Version::Same) != pkgCache::Version::Same)
+	 continue;
+
+      // not downloadable means the package is obsolete, so allow out-of-sync
+      if (CV.Downloadable() == false)
+	 continue;
+
+      PkgState[Pkg->ID].iFlags |= AutoKept;
+      if (unlikely(DebugMarker == true))
+	 std::clog << OutputInDepth(Depth) << "Ignore MarkInstall of " << APT::PrettyPkg(this, Pkg)
+	    << " as it is not in sync with its M-A:same sibling " << APT::PrettyPkg(this, P)
+	    << " (" << CandVer.VerStr() << " != " << CV.VerStr() << ")" << std::endl;
+      return false;
+   }
+
+   return true;
+}
+bool pkgDepCache::IsInstallOkDependenciesSatisfiableByCandidates(PkgIterator const &Pkg,
+      bool const AutoInst, unsigned long const Depth, bool const /*FromUser*/)
+{
+   if (AutoInst == false)
+      return true;
+
+   VerIterator const CandVer = PkgState[Pkg->ID].CandidateVerIter(*this);
+   if (unlikely(CandVer.end() == true) || CandVer == Pkg.CurrentVer())
+      return true;
+
+   for (DepIterator Dep = CandVer.DependsList(); Dep.end() != true;)
+   {
+      DepIterator Start = Dep;
+      bool foundSolution = false;
+      unsigned Ors = 0;
+      // Is it possible to satisfy this dependency?
+      for (bool LastOR = true; not Dep.end() && LastOR; ++Dep, ++Ors)
+      {
+	 LastOR = (Dep->CompareOp & Dep::Or) == Dep::Or;
+
+	 if ((DepState[Dep->ID] & (DepInstall | DepCVer)) != 0)
+	    foundSolution = true;
+      }
+
+      if (foundSolution || not Start.IsCritical() || Start.IsNegative())
+	 continue;
+
+      if (DebugAutoInstall == true)
+	 std::clog << OutputInDepth(Depth) << APT::PrettyDep(this, Start) << " can't be satisfied!" << std::endl;
+
+      // the dependency is critical, but can't be installed, so discard the candidate
+      // as the problemresolver will trip over it otherwise trying to install it (#735967)
+      StateCache &State = PkgState[Pkg->ID];
+      if (not State.Protect())
+      {
+	 if (Pkg->CurrentVer != 0)
+	    SetCandidateVersion(Pkg.CurrentVer());
+	 else
+	    State.CandidateVer = nullptr;
+	 if (not State.Delete())
+	 {
+	    State.Mode = ModeKeep;
+	    State.Update(Pkg, *this);
+	 }
+      }
+      return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// DepCache::SetReInstall - Set the reinstallation flag			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgDepCache::SetReInstall(PkgIterator const &Pkg,bool To)
+{
+   if (unlikely(Pkg.end() == true))
+      return;
+
+   APT::PackageList pkglist;
+   if (Pkg->CurrentVer != 0 &&
+       (Pkg.CurrentVer()-> MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+   {
+      pkgCache::GrpIterator Grp = Pkg.Group();
+      for (pkgCache::PkgIterator P = Grp.PackageList(); P.end() == false; P = Grp.NextPkg(P))
+      {
+	 if (P->CurrentVer != 0)
+	    pkglist.insert(P);
+      }
+   }
+   else
+      pkglist.insert(Pkg);
+
+   ActionGroup group(*this);
+
+   for (APT::PackageList::const_iterator Pkg = pkglist.begin(); Pkg != pkglist.end(); ++Pkg)
+   {
+      RemoveSizes(Pkg);
+      RemoveStates(Pkg);
+
+      StateCache &P = PkgState[Pkg->ID];
+      if (To == true)
+	 P.iFlags |= ReInstall;
+      else
+	 P.iFlags &= ~ReInstall;
+
+      AddStates(Pkg);
+      AddSizes(Pkg);
+   }
+}
+									/*}}}*/
+pkgCache::VerIterator pkgDepCache::GetCandidateVersion(PkgIterator const &Pkg)/*{{{*/
+{
+   return PkgState[Pkg->ID].CandidateVerIter(*this);
+}
+									/*}}}*/
+// DepCache::SetCandidateVersion - Change the candidate version		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgDepCache::SetCandidateVersion(VerIterator TargetVer)
+{
+   pkgCache::PkgIterator Pkg = TargetVer.ParentPkg();
+   StateCache &P = PkgState[Pkg->ID];
+
+   if (P.CandidateVer == TargetVer)
+      return;
+
+   ActionGroup group(*this);
+
+   RemoveSizes(Pkg);
+   RemoveStates(Pkg);
+
+   if (P.CandidateVer == P.InstallVer && P.Install() == true)
+      P.InstallVer = (Version *)TargetVer;
+   P.CandidateVer = (Version *)TargetVer;
+   P.Update(Pkg,*this);
+   
+   AddStates(Pkg);
+   Update(Pkg);
+   AddSizes(Pkg);
+
+}
+									/*}}}*/
+// DepCache::SetCandidateRelease - Change the candidate version		/*{{{*/
+// ---------------------------------------------------------------------
+/* changes the candidate of a package and walks over all its dependencies
+   to check if it needs to change the candidate of the dependency, too,
+   to reach a installable versionstate */
+bool pkgDepCache::SetCandidateRelease(pkgCache::VerIterator TargetVer,
+					std::string const &TargetRel)
+{
+   std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> > Changed;
+   return SetCandidateRelease(TargetVer, TargetRel, Changed);
+}
+bool pkgDepCache::SetCandidateRelease(pkgCache::VerIterator TargetVer,
+					std::string const &TargetRel,
+					std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> > &Changed)
+{
+   ActionGroup group(*this);
+   SetCandidateVersion(TargetVer);
+
+   if (TargetRel == "installed" || TargetRel == "candidate") // both doesn't make sense in this context
+      return true;
+
+   pkgVersionMatch Match(TargetRel, pkgVersionMatch::Release);
+   // save the position of the last element we will not undo - if we have to
+   std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> >::iterator newChanged = --(Changed.end());
+
+   for (pkgCache::DepIterator D = TargetVer.DependsList(); D.end() == false; ++D)
+   {
+      if (D->Type != pkgCache::Dep::PreDepends && D->Type != pkgCache::Dep::Depends &&
+	  ((D->Type != pkgCache::Dep::Recommends && D->Type != pkgCache::Dep::Suggests) ||
+	   IsImportantDep(D) == false))
+	 continue;
+
+      // walk over an or-group and check if we need to do anything
+      // for simpilicity no or-group is handled as a or-group including one dependency
+      pkgCache::DepIterator Start = D;
+      bool itsFine = false;
+      for (bool stillOr = true; stillOr == true; ++Start)
+      {
+	 stillOr = (Start->CompareOp & Dep::Or) == Dep::Or;
+	 pkgCache::PkgIterator const P = Start.TargetPkg();
+	 // virtual packages can't be a solution
+	 if (P.end() == true || (P->ProvidesList == 0 && P->VersionList == 0))
+	    continue;
+	 // if its already installed, check if this one is good enough
+	 pkgCache::VerIterator const Now = P.CurrentVer();
+	 if (Now.end() == false && Start.IsSatisfied(Now))
+	 {
+	    itsFine = true;
+	    break;
+	 }
+	 pkgCache::VerIterator const Cand = PkgState[P->ID].CandidateVerIter(*this);
+	 // no versioned dependency - but is it installable?
+	 if (Start.TargetVer() == 0 || Start.TargetVer()[0] == '\0')
+	 {
+	    // Check if one of the providers is installable
+	    if (P->ProvidesList != 0)
+	    {
+	       pkgCache::PrvIterator Prv = P.ProvidesList();
+	       for (; Prv.end() == false; ++Prv)
+	       {
+		  pkgCache::VerIterator const C = PkgState[Prv.OwnerPkg()->ID].CandidateVerIter(*this);
+		  if (C.end() == true || C != Prv.OwnerVer() ||
+		      (VersionState(C.DependsList(), DepInstall, DepCandMin, DepCandPolicy) & DepCandMin) != DepCandMin)
+		     continue;
+		  break;
+	       }
+	       if (Prv.end() == true)
+		  continue;
+	    }
+	    // no providers, so check if we have an installable candidate version
+	    else if (Cand.end() == true ||
+		(VersionState(Cand.DependsList(), DepInstall, DepCandMin, DepCandPolicy) & DepCandMin) != DepCandMin)
+	       continue;
+	    itsFine = true;
+	    break;
+	 }
+	 if (Cand.end() == true)
+	    continue;
+	 // check if the current candidate is enough for the versioned dependency - and installable?
+	 if (Start.IsSatisfied(Cand) == true &&
+	     (VersionState(Cand.DependsList(), DepInstall, DepCandMin, DepCandPolicy) & DepCandMin) == DepCandMin)
+	 {
+	    itsFine = true;
+	    break;
+	 }
+      }
+
+      if (itsFine == true) {
+	 // something in the or-group was fine, skip all other members
+	 for (; (D->CompareOp & Dep::Or) == Dep::Or; ++D);
+	 continue;
+      }
+
+      // walk again over the or-group and check each if a candidate switch would help
+      itsFine = false;
+      for (bool stillOr = true; stillOr == true; ++D)
+      {
+	 stillOr = (D->CompareOp & Dep::Or) == Dep::Or;
+	 // changing candidate will not help if the dependency is not versioned
+	 if (D.TargetVer() == 0 || D.TargetVer()[0] == '\0')
+	 {
+	    if (stillOr == true)
+	       continue;
+	    break;
+	 }
+
+	 pkgCache::VerIterator V;
+	 if (TargetRel == "newest")
+	    V = D.TargetPkg().VersionList();
+	 else
+	    V = Match.Find(D.TargetPkg());
+
+	 // check if the version from this release could satisfy the dependency
+	 if (V.end() == true || D.IsSatisfied(V) == false)
+	 {
+	    if (stillOr == true)
+	       continue;
+	    break;
+	 }
+
+	 pkgCache::VerIterator oldCand = PkgState[D.TargetPkg()->ID].CandidateVerIter(*this);
+	 if (V == oldCand)
+	 {
+	    // Do we already touched this Version? If so, their versioned dependencies are okay, no need to check again
+	    for (std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> >::const_iterator c = Changed.begin();
+		 c != Changed.end(); ++c)
+	    {
+	       if (c->first->ParentPkg != V->ParentPkg)
+		  continue;
+	       itsFine = true;
+	       break;
+	    }
+	 }
+
+	 if (itsFine == false)
+	 {
+	    // change the candidate
+	    Changed.emplace_back(V, TargetVer);
+	    if (SetCandidateRelease(V, TargetRel, Changed) == false)
+	    {
+	       if (stillOr == false)
+		  break;
+	       // undo the candidate changing
+	       SetCandidateVersion(oldCand);
+	       Changed.pop_back();
+	       continue;
+	    }
+	    itsFine = true;
+	 }
+
+	 // something in the or-group was fine, skip all other members
+	 for (; (D->CompareOp & Dep::Or) == Dep::Or; ++D);
+	 break;
+      }
+
+      if (itsFine == false && (D->Type == pkgCache::Dep::PreDepends || D->Type == pkgCache::Dep::Depends))
+      {
+	 // undo all changes which aren't lead to a solution
+	 for (std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> >::const_iterator c = ++newChanged;
+	      c != Changed.end(); ++c)
+	    SetCandidateVersion(c->first);
+	 Changed.erase(newChanged, Changed.end());
+	 return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// DepCache::MarkAuto - set the Auto flag for a package			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgDepCache::MarkAuto(const PkgIterator &Pkg, bool Auto)
+{
+  StateCache &state = PkgState[Pkg->ID];
+
+  ActionGroup group(*this);
+
+  if(Auto)
+    state.Flags |= Flag::Auto;
+  else
+    state.Flags &= ~Flag::Auto;
+}
+									/*}}}*/
+// StateCache::Update - Compute the various static display things	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called whenever the Candidate version changes. */
+void pkgDepCache::StateCache::Update(PkgIterator Pkg,pkgCache &Cache)
+{
+   // Some info
+   VerIterator Ver = CandidateVerIter(Cache);
+
+   // Use a null string or the version string
+   if (Ver.end() == true)
+      CandVersion = "";
+   else
+      CandVersion = Ver.VerStr();
+
+   // Find the current version
+   if (Pkg->CurrentVer != 0)
+      CurVersion = Pkg.CurrentVer().VerStr();
+   else
+      CurVersion = "";
+
+   // Figure out if its up or down or equal
+   if (Pkg->CurrentVer == 0 || Pkg->VersionList == 0 || CandidateVer == 0)
+      Status = 2;
+   else
+      Status = Ver.CompareVer(Pkg.CurrentVer());
+}
+									/*}}}*/
+// Policy::GetCandidateVer - Returns the Candidate install version	/*{{{*/
+// ---------------------------------------------------------------------
+/* The default just returns the highest available version that is not
+   a source and automatic. */
+pkgCache::VerIterator pkgDepCache::Policy::GetCandidateVer(PkgIterator const &Pkg)
+{
+   /* Not source/not automatic versions cannot be a candidate version 
+      unless they are already installed */
+   VerIterator Last;
+   
+   for (VerIterator I = Pkg.VersionList(); I.end() == false; ++I)
+   {
+      if (Pkg.CurrentVer() == I)
+	 return I;
+      
+      for (VerFileIterator J = I.FileList(); J.end() == false; ++J)
+      {
+	 if (J.File().Flagged(Flag::NotSource))
+	    continue;
+
+	 /* Stash the highest version of a not-automatic source, we use it
+	    if there is nothing better */
+	 if (J.File().Flagged(Flag::NotAutomatic) ||
+	     J.File().Flagged(Flag::ButAutomaticUpgrades))
+	 {
+	    if (Last.end() == true)
+	       Last = I;
+	    continue;
+	 }
+
+	 return I;
+      }
+   }
+   
+   return Last;
+}
+									/*}}}*/
+// Policy::IsImportantDep - True if the dependency is important		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgDepCache::Policy::IsImportantDep(DepIterator const &Dep) const
+{
+   if(Dep.IsCritical())
+      return true;
+   else if(Dep->Type == pkgCache::Dep::Recommends)
+   {
+      if (InstallRecommends)
+	 return true;
+      // we support a special mode to only install-recommends for certain
+      // sections
+      // FIXME: this is a meant as a temporary solution until the
+      //        recommends are cleaned up
+      const char *sec = Dep.ParentVer().Section();
+      if (sec && SectionInSubTree("APT::Install-Recommends-Sections", sec))
+	 return true;
+   }
+   else if(Dep->Type == pkgCache::Dep::Suggests)
+      return InstallSuggests;
+
+   return false;
+}
+									/*}}}*/
+// Policy::GetPriority - Get the priority of the package pin		/*{{{*/
+APT_PURE signed short pkgDepCache::Policy::GetPriority(pkgCache::PkgIterator const &/*Pkg*/)
+{ return 0; }
+APT_PURE signed short pkgDepCache::Policy::GetPriority(pkgCache::VerIterator const &/*Ver*/, bool /*ConsiderFiles*/)
+{ return 0; }
+APT_PURE signed short pkgDepCache::Policy::GetPriority(pkgCache::PkgFileIterator const &/*File*/)
+{ return 0; }
+									/*}}}*/
+pkgDepCache::InRootSetFunc *pkgDepCache::GetRootSetFunc()		/*{{{*/
+{
+   DefaultRootSetFunc *f = new DefaultRootSetFunc2(&GetCache());
+   if (f->wasConstructedSuccessfully())
+      return f;
+   else
+   {
+      delete f;
+      return NULL;
+   }
+}
+
+pkgDepCache::InRootSetFunc *pkgDepCache::GetCachedRootSetFunc()
+{
+   if (d->inRootSetFunc == nullptr)
+      d->inRootSetFunc.reset(GetRootSetFunc());
+   return d->inRootSetFunc.get();
+}
+									/*}}}*/
+bool pkgDepCache::MarkFollowsRecommends()				/*{{{*/
+{
+  return _config->FindB("APT::AutoRemove::RecommendsImportant", true);
+}
+									/*}}}*/
+bool pkgDepCache::MarkFollowsSuggests()					/*{{{*/
+{
+  return _config->FindB("APT::AutoRemove::SuggestsImportant", true);
+}
+									/*}}}*/
+static bool IsPkgInBoringState(pkgCache::PkgIterator const &Pkg, pkgDepCache::StateCache const * const PkgState)/*{{{*/
+{
+   if (Pkg->CurrentVer == 0)
+   {
+      if (PkgState[Pkg->ID].Keep())
+	 return true;
+   }
+   else
+   {
+      if (PkgState[Pkg->ID].Delete())
+	 return true;
+   }
+   return false;
+}
+									/*}}}*/
+// MarkPackage - mark a single package in Mark-and-Sweep		/*{{{*/
+static bool MarkPackage(pkgCache::PkgIterator const &Pkg,
+			pkgCache::VerIterator const &Ver,
+			bool const follow_recommends,
+			bool const follow_suggests,
+			bool const debug_autoremove,
+			std::string_view const reason,
+			size_t const Depth,
+			pkgCache &Cache,
+			pkgDepCache &DepCache,
+			pkgDepCache::StateCache *const PkgState,
+			std::vector<bool> &fullyExplored,
+			std::unique_ptr<APT::CacheFilter::Matcher> &IsAVersionedKernelPackage,
+			std::unique_ptr<APT::CacheFilter::Matcher> &IsProtectedKernelPackage)
+{
+   if (Ver.end() || PkgState[Pkg->ID].Marked)
+      return true;
+
+   if (IsPkgInBoringState(Pkg, PkgState))
+   {
+      fullyExplored[Pkg->ID] = true;
+      return true;
+   }
+
+   // we are not trying too hard…
+   if (unlikely(Depth > 3000))
+      return false;
+
+   PkgState[Pkg->ID].Marked = true;
+   if(debug_autoremove)
+      std::clog << "Marking: " << Pkg.FullName() << " " << Ver.VerStr()
+		<< " (" << reason << ")" << std::endl;
+
+   auto const sort_by_source_version = [](pkgCache::VerIterator const &A, pkgCache::VerIterator const &B) {
+      auto const verret = A.Cache()->VS->CmpVersion(A.SourceVerStr(), B.SourceVerStr());
+      if (verret != 0)
+	 return verret < 0;
+      return A->ID < B->ID;
+   };
+
+   for (auto D = Ver.DependsList(); not D.end(); ++D)
+   {
+      auto const T = D.TargetPkg();
+      if (T.end() || fullyExplored[T->ID])
+	 continue;
+
+      if (D->Type != pkgCache::Dep::Depends &&
+	    D->Type != pkgCache::Dep::PreDepends &&
+	    (not follow_recommends || D->Type != pkgCache::Dep::Recommends) &&
+	    (not follow_suggests || D->Type != pkgCache::Dep::Suggests))
+	 continue;
+
+      bool unsatisfied_choice = false;
+      std::unordered_map<std::string, APT::VersionVector> providers_by_source;
+      // collect real part
+      if (not IsPkgInBoringState(T, PkgState))
+      {
+	 auto const TV = (PkgState[T->ID].Install()) ? PkgState[T->ID].InstVerIter(DepCache) : T.CurrentVer();
+	 if (likely(not TV.end()))
+	 {
+	    if (not D.IsSatisfied(TV))
+	       unsatisfied_choice = true;
+	    else
+	       providers_by_source[TV.SourcePkgName()].push_back(TV);
+	 }
+      }
+      if (providers_by_source.empty() && not unsatisfied_choice)
+	 PkgState[T->ID].Marked = true;
+      // collect virtual part
+      for (auto Prv = T.ProvidesList(); not Prv.end(); ++Prv)
+      {
+	 auto const PP = Prv.OwnerPkg();
+	 if (IsPkgInBoringState(PP, PkgState))
+	    continue;
+
+	 // we want to ignore provides from uninteresting versions
+	 auto const PV = (PkgState[PP->ID].Install()) ?
+	    PkgState[PP->ID].InstVerIter(DepCache) : PP.CurrentVer();
+	 if (unlikely(PV.end()) || PV != Prv.OwnerVer())
+	    continue;
+
+	 if (not D.IsSatisfied(Prv))
+	    unsatisfied_choice = true;
+	 else
+	    providers_by_source[PV.SourcePkgName()].push_back(PV);
+      }
+      // only latest binary package of a source package is marked instead of all
+      for (auto &providers : providers_by_source)
+      {
+	 auto const highestSrcVer = (*std::max_element(providers.second.begin(), providers.second.end(), sort_by_source_version)).SourceVerStr();
+	 providers.second.erase(std::remove_if(providers.second.begin(), providers.second.end(), [&](auto const &V) { return strcmp(highestSrcVer, V.SourceVerStr()) != 0; }), providers.second.end());
+	 // if the provider is a versioned kernel package mark them only for protected kernels
+	 if (providers.second.size() == 1)
+	    continue;
+	 if (not IsAVersionedKernelPackage)
+	    IsAVersionedKernelPackage = [&]() -> std::unique_ptr<APT::CacheFilter::Matcher> {
+	       auto const patterns = _config->FindVector("APT::VersionedKernelPackages");
+	       if (patterns.empty())
+		  return std::make_unique<APT::CacheFilter::FalseMatcher>();
+	       std::ostringstream regex;
+	       regex << '^';
+	       std::copy(patterns.begin(), patterns.end() - 1, std::ostream_iterator<std::string>(regex, "-.*$|^"));
+	       regex << patterns.back() << "-.*$";
+	       return std::make_unique<APT::CacheFilter::PackageNameMatchesRegEx>(regex.str());
+	    }();
+	 if (not std::all_of(providers.second.begin(), providers.second.end(), [&](auto const &Prv) { return (*IsAVersionedKernelPackage)(Prv.ParentPkg()); }))
+	    continue;
+	 // … if there is at least one for protected kernels installed
+	 if (not IsProtectedKernelPackage)
+	    IsProtectedKernelPackage = APT::KernelAutoRemoveHelper::GetProtectedKernelsFilter(&Cache);
+	 if (not std::any_of(providers.second.begin(), providers.second.end(), [&](auto const &Prv) { return (*IsProtectedKernelPackage)(Prv.ParentPkg()); }))
+	    continue;
+	 providers.second.erase(std::remove_if(providers.second.begin(), providers.second.end(),
+					       [&](auto const &Prv) { return not((*IsProtectedKernelPackage)(Prv.ParentPkg())); }),
+				providers.second.end());
+      }
+
+      if (not unsatisfied_choice)
+	 fullyExplored[T->ID] = true;
+      for (auto const &providers : providers_by_source)
+      {
+	 for (auto const &PV : providers.second)
+	 {
+	    auto const PP = PV.ParentPkg();
+	    if (debug_autoremove)
+	       std::clog << "Following dep: " << APT::PrettyDep(&DepCache, D)
+			 << ", provided by " << PP.FullName() << " " << PV.VerStr()
+			 << " (" << providers_by_source.size() << "/" << providers.second.size() << ")\n";
+	    if (not MarkPackage(PP, PV, follow_recommends, follow_suggests, debug_autoremove,
+				"Dependency", Depth + 1, Cache, DepCache, PkgState, fullyExplored,
+				IsAVersionedKernelPackage, IsProtectedKernelPackage))
+	       return false;
+	 }
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// pkgDepCache::MarkRequired - the main mark algorithm			/*{{{*/
+bool pkgDepCache::MarkRequired(InRootSetFunc &userFunc)
+{
+   if (_config->Find("APT::Solver", "internal") != "internal")
+      return true;
+
+   // init the states
+   auto const PackagesCount = Head().PackageCount;
+   for(auto i = decltype(PackagesCount){0}; i < PackagesCount; ++i)
+   {
+      PkgState[i].Marked  = false;
+      PkgState[i].Garbage = false;
+   }
+   std::vector<bool> fullyExplored(PackagesCount, false);
+
+   bool const debug_autoremove = _config->FindB("Debug::pkgAutoRemove", false);
+   if (debug_autoremove)
+      for(PkgIterator p = PkgBegin(); !p.end(); ++p)
+	 if(PkgState[p->ID].Flags & Flag::Auto)
+	    std::clog << "AutoDep: " << p.FullName() << std::endl;
+
+   bool const follow_recommends = MarkFollowsRecommends();
+   bool const follow_suggests   = MarkFollowsSuggests();
+
+   // do the mark part, this is the core bit of the algorithm
+   for (PkgIterator P = PkgBegin(); !P.end(); ++P)
+   {
+      if (PkgState[P->ID].Marked || IsPkgInBoringState(P, PkgState))
+	 continue;
+
+      std::string_view reason;
+      if ((PkgState[P->ID].Flags & Flag::Auto) == 0)
+	 reason = "Manual-Installed";
+      else if (P->Flags & Flag::Essential)
+	 reason = "Essential";
+      else if (P->Flags & Flag::Important)
+	 reason = "Important";
+      else if (P->CurrentVer != 0 && P.CurrentVer()->Priority == pkgCache::State::Required)
+	 reason = "Required";
+      else if (userFunc.InRootSet(P))
+	 reason = "Blacklisted [APT::NeverAutoRemove]";
+      else if (not IsModeChangeOk(*this, ModeGarbage, P, 0, false, DebugMarker))
+	 reason = "Hold";
+      else
+	 continue;
+
+      pkgCache::VerIterator const PV = (PkgState[P->ID].Install()) ? PkgState[P->ID].InstVerIter(*this) : P.CurrentVer();
+      if (not MarkPackage(P, PV, follow_recommends, follow_suggests, debug_autoremove,
+			  reason, 0, *Cache, *this, PkgState, fullyExplored,
+			  d->IsAVersionedKernelPackage, d->IsProtectedKernelPackage))
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+bool pkgDepCache::Sweep()						/*{{{*/
+{
+   bool debug_autoremove = _config->FindB("Debug::pkgAutoRemove",false);
+
+   // do the sweep
+   for(PkgIterator p=PkgBegin(); !p.end(); ++p)
+   {
+     StateCache &state=PkgState[p->ID];
+
+     // skip required packages
+     if (!p.CurrentVer().end() && 
+	 (p.CurrentVer()->Priority == pkgCache::State::Required))
+	continue;
+
+     // if it is not marked and it is installed, it's garbage 
+     if(!state.Marked && (!p.CurrentVer().end() || state.Install()))
+     {
+	state.Garbage=true;
+	if(debug_autoremove)
+	   std::clog << "Garbage: " << p.FullName() << std::endl;
+     }
+  }   
+
+   return true;
+}
+									/*}}}*/
+// DepCache::MarkAndSweep						/*{{{*/
+bool pkgDepCache::MarkAndSweep(InRootSetFunc &rootFunc)
+{
+   return MarkRequired(rootFunc) && Sweep();
+}
+bool pkgDepCache::MarkAndSweep()
+{
+   InRootSetFunc *f(GetCachedRootSetFunc());
+   if (f != NULL)
+      return MarkAndSweep(*f);
+   else
+      return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/depcache.h b/apt-pkg/depcache.h
new file mode 100644
index 0000000..be27b1d
--- /dev/null
+++ b/apt-pkg/depcache.h
@@ -0,0 +1,509 @@
+// -*- mode: c++; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   DepCache - Dependency Extension data for the cache
+   
+   This class stores the cache data and a set of extension structures for
+   monitoring the current state of all the packages. It also generates and
+   caches the 'install' state of many things. This refers to the state of the
+   package after an install has been run.
+
+   The StateCache::State field can be -1,0,1,2 which is <,=,>,no current.
+   StateCache::Mode is which of the 3 fields is active.
+   
+   This structure is important to support the readonly status of the cache 
+   file. When the data is saved the cache will be refereshed from our 
+   internal rep and written to disk. Then the actual persistent data
+   files will be put on the disk.
+
+   Each dependency is compared against 3 target versions to produce to
+   3 dependency results.
+     Now - Compared using the Currently install version
+     Install - Compared using the install version (final state)
+     CVer - (Candidate Version) Compared using the Candidate Version
+   The candidate and now results are used to decide whether a package
+   should be automatically installed or if it should be left alone.
+   
+   Remember, the Candidate Version is selected based on the distribution
+   settings for the Package. The Install Version is selected based on the
+   state (Delete, Keep, Install) field and can be either the Current Version
+   or the Candidate version.
+   
+   The Candidate version is what is shown the 'Install Version' field.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DEPCACHE_H
+#define PKGLIB_DEPCACHE_H
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <stddef.h>
+
+#include <list>
+#include <memory>
+#include <string>
+#include <utility>
+
+
+class OpProgress;
+class pkgVersioningSystem;
+namespace APT
+{
+template <class Container>
+class PackageContainer;
+using PackageVector = PackageContainer<std::vector<pkgCache::PkgIterator>>;
+} // namespace APT
+
+class APT_PUBLIC pkgDepCache : protected pkgCache::Namespace
+{
+   public:
+
+   /** \brief An arbitrary predicate on packages. */
+   class APT_PUBLIC InRootSetFunc
+   {
+   public:
+     virtual bool InRootSet(const pkgCache::PkgIterator &/*pkg*/) {return false;};
+     virtual ~InRootSetFunc() {};
+   };
+
+   private:
+   /** \brief Update the Marked field of all packages.
+    *
+    *  Each package's StateCache::Marked field will be set to \b true
+    *  if and only if it can be reached from the root set.  By
+    *  default, the root set consists of the set of manually installed
+    *  or essential packages, but it can be extended using the
+    *  parameter #rootFunc.
+    *
+    *  \param rootFunc A callback that can be used to add extra
+    *  packages to the root set.
+    *
+    *  \return \b false if an error occurred.
+    */
+   bool MarkRequired(InRootSetFunc &rootFunc);
+
+   /** \brief Set the StateCache::Garbage flag on all packages that
+    *  should be removed.
+    *
+    *  Packages that were not marked by the last call to #MarkRequired
+    *  are tested to see whether they are actually garbage.  If so,
+    *  they are marked as such.
+    *
+    *  \return \b false if an error occurred.
+    */
+   bool Sweep();
+
+   public:
+   
+   // These flags are used in DepState
+   enum DepFlags {DepNow = (1 << 0),DepInstall = (1 << 1),DepCVer = (1 << 2),
+                  DepGNow = (1 << 3),DepGInstall = (1 << 4),DepGCVer = (1 << 5)};
+
+   // These flags are used in StateCache::DepState
+   enum DepStateFlags {DepNowPolicy = (1 << 0), DepNowMin = (1 << 1),
+                       DepInstPolicy = (1 << 2), DepInstMin = (1 << 3),
+                       DepCandPolicy = (1 << 4), DepCandMin = (1 << 5)};
+   
+   // These flags are used in StateCache::iFlags
+   enum InternalFlags {AutoKept = (1 << 0), Purge = (1 << 1), ReInstall = (1 << 2), Protected = (1 << 3)};
+      
+   enum VersionTypes {NowVersion, InstallVersion, CandidateVersion};
+   enum ModeList {ModeDelete = 0, ModeKeep = 1, ModeInstall = 2, ModeGarbage = 3};
+
+   /** \brief Represents an active action group.
+    *
+    *  An action group is a group of actions that are currently being
+    *  performed.  While an active group is active, certain routine
+    *  clean-up actions that would normally be performed after every
+    *  cache operation are delayed until the action group is
+    *  completed.  This is necessary primarily to avoid inefficiencies
+    *  when modifying a large number of packages at once.
+    *
+    *  This class represents an active action group.  Creating an
+    *  instance will create an action group; destroying one will
+    *  destroy the corresponding action group.
+    *
+    *  The following operations are suppressed by this class:
+    *
+    *    - Keeping the Marked and Garbage flags up to date.
+    *
+    *  \note This can be used in the future to easily accumulate
+    *  atomic actions for undo or to display "what apt did anyway";
+    *  e.g., change the counter of how many action groups are active
+    *  to a std::set of pointers to them and use those to store
+    *  information about what happened in a group in the group.
+    */
+   class APT_PUBLIC ActionGroup
+   {
+       void * const d;
+       pkgDepCache &cache;
+
+       bool released;
+
+       /** Action groups are noncopyable. */
+       APT_HIDDEN ActionGroup(const ActionGroup &other);
+   public:
+       /** \brief Create a new ActionGroup.
+	*
+	*  \param cache The cache that this ActionGroup should
+	*  manipulate.
+	*
+	*  As long as this object exists, no automatic cleanup
+	*  operations will be undertaken.
+	*/
+       explicit ActionGroup(pkgDepCache &cache);
+
+       /** \brief Clean up the action group before it is destroyed.
+        *
+        *  If it is destroyed later, no second cleanup will be run.
+	*/
+       void release();
+
+       /** \brief Destroy the action group.
+	*
+	*  If this is the last action group, the automatic cache
+	*  cleanup operations will be undertaken.
+	*/
+       virtual ~ActionGroup();
+   };
+
+   /** \brief Returns \b true for packages matching a regular
+    *  expression in APT::NeverAutoRemove.
+    */
+   class APT_PUBLIC DefaultRootSetFunc : public InRootSetFunc, public Configuration::MatchAgainstConfig
+   {
+   public:
+     DefaultRootSetFunc() : Configuration::MatchAgainstConfig("APT::NeverAutoRemove") {};
+     virtual ~DefaultRootSetFunc() {};
+
+     bool InRootSet(const pkgCache::PkgIterator &pkg) APT_OVERRIDE { return pkg.end() == false && Match(pkg.Name()); };
+   };
+
+   struct APT_PUBLIC StateCache
+   {
+      // text versions of the two version fields
+      const char *CandVersion;
+      const char *CurVersion;
+
+      // Pointer to the candidate install version. 
+      Version *CandidateVer;
+
+      // Pointer to the install version.
+      Version *InstallVer;
+      
+      // Copy of Package::Flags
+      unsigned short Flags;
+      unsigned short iFlags;           // Internal flags
+
+      /** \brief \b true if this package can be reached from the root set. */
+      bool Marked;
+
+      /** \brief \b true if this package is unused and should be removed.
+       *
+       *  This differs from !#Marked, because it is possible that some
+       *  unreachable packages will be protected from becoming
+       *  garbage.
+       */
+      bool Garbage;
+
+      // Various tree indicators
+      signed char Status;              // -1,0,1,2
+      unsigned char Mode;              // ModeList
+      unsigned char DepState;          // DepState Flags
+
+      // Update of candidate version
+      void Update(PkgIterator Pkg,pkgCache &Cache);
+      
+      // Various test members for the current status of the package
+      inline bool NewInstall() const {return Status == 2 && Mode == ModeInstall;};
+      inline bool Delete() const {return Mode == ModeDelete;};
+      inline bool Purge() const {return Delete() == true && (iFlags & pkgDepCache::Purge) == pkgDepCache::Purge; };
+      inline bool Keep() const {return Mode == ModeKeep;};
+      inline bool Protect() const {return (iFlags & Protected) == Protected;};
+      inline bool Upgrade() const {return Status > 0 && Mode == ModeInstall;};
+      inline bool Upgradable() const {return Status >= 1 && CandidateVer != NULL;};
+      inline bool Downgrade() const {return Status < 0 && Mode == ModeInstall;};
+      inline bool Held() const {return Status != 0 && Keep();};
+      inline bool NowBroken() const {return (DepState & DepNowMin) != DepNowMin;};
+      inline bool NowPolicyBroken() const {return (DepState & DepNowPolicy) != DepNowPolicy;};
+      inline bool InstBroken() const {return (DepState & DepInstMin) != DepInstMin;};
+      inline bool InstPolicyBroken() const {return (DepState & DepInstPolicy) != DepInstPolicy;};
+      inline bool Install() const {return Mode == ModeInstall;};
+      inline bool ReInstall() const {return Delete() == false && (iFlags & pkgDepCache::ReInstall) == pkgDepCache::ReInstall;};
+      inline VerIterator InstVerIter(pkgCache &Cache)
+                {return VerIterator(Cache,InstallVer);};
+      inline VerIterator CandidateVerIter(pkgCache &Cache)
+                {return VerIterator(Cache,CandidateVer);};
+   };
+   
+   // Helper functions
+   void BuildGroupOrs(VerIterator const &V);
+   void UpdateVerState(PkgIterator const &Pkg);
+
+   // User Policy control
+   class APT_PUBLIC Policy
+   {
+      public:
+      Policy() {
+         InstallRecommends = _config->FindB("APT::Install-Recommends", false);
+         InstallSuggests = _config->FindB("APT::Install-Suggests", false);
+      }
+
+      virtual VerIterator GetCandidateVer(PkgIterator const &Pkg);
+      virtual bool IsImportantDep(DepIterator const &Dep) const;
+      virtual signed short GetPriority(PkgIterator const &Pkg);
+      virtual signed short GetPriority(VerIterator const &Ver, bool ConsiderFiles=true);
+      virtual signed short GetPriority(PkgFileIterator const &File);
+
+      virtual ~Policy() {};
+
+      private:
+      bool InstallRecommends;
+      bool InstallSuggests;
+   };
+
+   private:
+   /** The number of open "action groups"; certain post-action
+    *  operations are suppressed if this number is > 0.
+    */
+   int group_level;
+
+   friend class ActionGroup;
+   public:
+   int IncreaseActionGroupLevel();
+   int DecreaseActionGroupLevel();
+
+   protected:
+
+   // State information
+   pkgCache *Cache;
+   StateCache *PkgState;
+   unsigned char *DepState;
+
+   /** Stores the space changes after installation */
+   signed long long iUsrSize;
+   /** Stores how much we need to download to get the packages */
+   unsigned long long iDownloadSize;
+   unsigned long iInstCount;
+   unsigned long iDelCount;
+   unsigned long iKeepCount;
+   unsigned long iBrokenCount;
+   unsigned long iPolicyBrokenCount;
+   unsigned long iBadCount;
+
+   bool DebugMarker;
+   bool DebugAutoInstall;
+
+   Policy *delLocalPolicy;           // For memory clean up..
+   Policy *LocalPolicy;
+   
+   // Check for a matching provides
+   bool CheckDep(DepIterator const &Dep,int const Type,PkgIterator &Res);
+   inline bool CheckDep(DepIterator const &Dep,int const Type)
+   {
+      PkgIterator Res(*this,0);
+      return CheckDep(Dep,Type,Res);
+   }
+   
+   // Computes state information for deps and versions (w/o storing)
+   unsigned char DependencyState(DepIterator const &D);
+   unsigned char VersionState(DepIterator D,unsigned char const Check,
+			      unsigned char const SetMin,
+			      unsigned char const SetPolicy) const;
+
+   // Recalculates various portions of the cache, call after changing something
+   void Update(DepIterator Dep);           // Mostly internal
+   void Update(PkgIterator const &P);
+   
+   // Count manipulators
+   void AddSizes(const PkgIterator &Pkg, bool const Invert = false);
+   inline void RemoveSizes(const PkgIterator &Pkg) {AddSizes(Pkg, true);};
+   void AddStates(const PkgIterator &Pkg, bool const Invert = false);
+   inline void RemoveStates(const PkgIterator &Pkg) {AddStates(Pkg,true);};
+   
+   public:
+
+   // Legacy.. We look like a pkgCache
+   inline operator pkgCache &() {return *Cache;};
+   inline Header &Head() {return *Cache->HeaderP;};
+   inline GrpIterator GrpBegin() {return Cache->GrpBegin();};
+   inline PkgIterator PkgBegin() {return Cache->PkgBegin();};
+   inline GrpIterator FindGrp(APT::StringView Name) {return Cache->FindGrp(Name);};
+   inline PkgIterator FindPkg(APT::StringView Name) {return Cache->FindPkg(Name);};
+   inline PkgIterator FindPkg(APT::StringView Name, APT::StringView Arch) {return Cache->FindPkg(Name, Arch);};
+
+   inline pkgCache &GetCache() {return *Cache;};
+   inline pkgVersioningSystem &VS() {return *Cache->VS;};
+
+   inline bool IsImportantDep(DepIterator Dep) const {return LocalPolicy->IsImportantDep(Dep);};
+   inline Policy &GetPolicy() {return *LocalPolicy;};
+   
+   // Accessors
+   inline StateCache &operator [](PkgIterator const &I) {return PkgState[I->ID];};
+   inline StateCache &operator [](PkgIterator const &I) const {return PkgState[I->ID];};
+   inline unsigned char &operator [](DepIterator const &I) {return DepState[I->ID];};
+   inline unsigned char const &operator [](DepIterator const &I) const {return DepState[I->ID];};
+
+   /** \return A function identifying packages in the root set other
+    *  than manually installed packages and essential packages, or \b
+    *  NULL if an error occurs.
+    *
+    *  \todo Is this the best place for this function?  Perhaps the
+    *  settings for mark-and-sweep should be stored in a single
+    *  external class?
+    */
+   virtual InRootSetFunc *GetRootSetFunc();
+
+   /** This should return const really - do not delete. */
+   InRootSetFunc *GetCachedRootSetFunc() APT_HIDDEN;
+
+   /** \return \b true if the garbage collector should follow recommendations.
+    */
+   virtual bool MarkFollowsRecommends();
+
+   /** \return \b true if the garbage collector should follow suggestions.
+    */
+   virtual bool MarkFollowsSuggests();
+
+   /** \brief Update the Marked and Garbage fields of all packages.
+    *
+    *  This routine is implicitly invoked after all state manipulators
+    *  and when an ActionGroup is destroyed.  It invokes the private
+    *  MarkRequired() and Sweep() to do its dirty work.
+    *
+    *  \param rootFunc A predicate that returns \b true for packages
+    *  that should be added to the root set.
+    */
+   bool MarkAndSweep(InRootSetFunc &rootFunc);
+   bool MarkAndSweep();
+
+   /** \name State Manipulators
+    */
+   // @{
+   bool MarkKeep(PkgIterator const &Pkg, bool Soft = false,
+		 bool FromUser = true, unsigned long Depth = 0);
+   bool MarkDelete(PkgIterator const &Pkg, bool MarkPurge = false,
+                   unsigned long Depth = 0, bool FromUser = true);
+   bool MarkInstall(PkgIterator const &Pkg,bool AutoInst = true,
+		    unsigned long Depth = 0, bool FromUser = true,
+		    bool ForceImportantDeps = false);
+   void MarkProtected(PkgIterator const &Pkg) { PkgState[Pkg->ID].iFlags |= Protected; };
+
+   void SetReInstall(PkgIterator const &Pkg,bool To);
+
+   /** @return 'the' candidate version of a package
+    *
+    * The version returned is the version previously set explicitly via
+    * SetCandidate* methods like #SetCandidateVersion or if there wasn't one
+    * set the version as chosen via #Policy.
+    *
+    * @param Pkg is the package to return the candidate for
+    */
+   pkgCache::VerIterator GetCandidateVersion(pkgCache::PkgIterator const &Pkg);
+   void SetCandidateVersion(VerIterator TargetVer);
+   bool SetCandidateRelease(pkgCache::VerIterator TargetVer,
+				std::string const &TargetRel);
+   /** Set the candidate version for dependencies too if needed.
+    *
+    *  Sets not only the candidate version as SetCandidateVersion does,
+    *  but walks also down the dependency tree and checks if it is required
+    *  to set the candidate of the dependency to a version from the given
+    *  release, too.
+    *
+    *  \param TargetVer new candidate version of the package
+    *  \param TargetRel try to switch to this release if needed
+    *  \param[out] Changed a list of pairs consisting of the \b old
+    *              version of the changed package and the version which
+    *              required the switch of this dependency
+    *  \return \b true if the switch was successful, \b false otherwise
+    */
+   bool SetCandidateRelease(pkgCache::VerIterator TargetVer,
+			    std::string const &TargetRel,
+			    std::list<std::pair<pkgCache::VerIterator, pkgCache::VerIterator> > &Changed);
+
+   /** Set the "is automatically installed" flag of Pkg. */
+   void MarkAuto(const PkgIterator &Pkg, bool Auto);
+   // @}
+
+   /** \return \b true if it's OK for MarkInstall to install
+    *  the given package.
+    *
+    *  The default implementation simply calls all IsInstallOk*
+    *  method mentioned below.
+    *
+    *  Overriding implementations should use the hold-state-flag to
+    *  cache results from previous checks of this package - if possible.
+    *
+    *  The parameters are the same as in the calling MarkInstall:
+    *  \param Pkg       the package that MarkInstall wants to install.
+    *  \param AutoInst  install this and all its dependencies
+    *  \param Depth     recursive deep of this Marker call
+    *  \param FromUser  was the install requested by the user?
+    */
+   virtual bool IsInstallOk(const PkgIterator &Pkg,bool AutoInst = true,
+			    unsigned long Depth = 0, bool FromUser = true);
+
+   /** \return \b true if it's OK for MarkDelete to remove
+    *  the given package.
+    *
+    *  The default implementation simply calls all IsDeleteOk*
+    *  method mentioned below, see also #IsInstallOk.
+    *
+    *  The parameters are the same as in the calling MarkDelete:
+    *  \param Pkg       the package that MarkDelete wants to remove.
+    *  \param MarkPurge should we purge instead of "only" remove?
+    *  \param Depth     recursive deep of this Marker call
+    *  \param FromUser  was the remove requested by the user?
+    */
+   virtual bool IsDeleteOk(const PkgIterator &Pkg,bool MarkPurge = false,
+			    unsigned long Depth = 0, bool FromUser = true);
+
+   // read persistent states
+   bool readStateFile(OpProgress * const prog);
+   bool writeStateFile(OpProgress * const prog, bool const InstalledOnly=true);
+   
+   // Size queries
+   inline signed long long UsrSize() {return iUsrSize;};
+   inline unsigned long long DebSize() {return iDownloadSize;};
+   inline unsigned long DelCount() {return iDelCount;};
+   inline unsigned long KeepCount() {return iKeepCount;};
+   inline unsigned long InstCount() {return iInstCount;};
+   inline unsigned long BrokenCount() {return iBrokenCount;};
+   inline unsigned long PolicyBrokenCount() {return iPolicyBrokenCount;};
+   inline unsigned long BadCount() {return iBadCount;};
+
+   bool Init(OpProgress * const Prog);
+   // Generate all state information
+   void Update(OpProgress * const Prog = 0);
+
+   pkgDepCache(pkgCache * const Cache,Policy * const Plcy = 0);
+   virtual ~pkgDepCache();
+
+   bool CheckConsistency(char const *const msgtag = "");
+
+   protected:
+   // methods call by IsInstallOk
+   bool IsInstallOkMultiArchSameVersionSynced(PkgIterator const &Pkg,
+	 bool const AutoInst, unsigned long const Depth, bool const FromUser);
+   bool IsInstallOkDependenciesSatisfiableByCandidates(PkgIterator const &Pkg,
+      bool const AutoInst, unsigned long const Depth, bool const FromUser);
+
+   // methods call by IsDeleteOk
+   bool IsDeleteOkProtectInstallRequests(PkgIterator const &Pkg,
+	 bool const rPurge, unsigned long const Depth, bool const FromUser);
+
+   private:
+   struct Private;
+   Private *const d;
+
+   APT_HIDDEN bool MarkInstall_StateChange(PkgIterator const &Pkg, bool AutoInst, bool FromUser);
+   APT_HIDDEN bool MarkInstall_DiscardInstall(PkgIterator const &Pkg);
+
+   APT_HIDDEN void PerformDependencyPass(OpProgress * const Prog);
+};
+
+#endif
diff --git a/apt-pkg/dirstream.cc b/apt-pkg/dirstream.cc
new file mode 100644
index 0000000..d6cf0ab
--- /dev/null
+++ b/apt-pkg/dirstream.cc
@@ -0,0 +1,118 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Directory Stream 
+   
+   This class provides a simple basic extractor that can be used for
+   a number of purposes.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/error.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <apti18n.h>
+									/*}}}*/
+
+// DirStream::DoItem - Process an item					/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a very simple extractor, it does not deal with things like
+   overwriting directories with files and so on. */
+bool pkgDirStream::DoItem(Item &Itm,int &Fd)
+{
+   switch (Itm.Type)
+   {
+      case Item::File:
+      {
+	 /* Open the output file, NDELAY is used to prevent this from 
+	    blowing up on device special files.. */
+	 int iFd = open(Itm.Name,O_NDELAY|O_WRONLY|O_CREAT|O_TRUNC|O_APPEND,
+		       Itm.Mode);
+	 if (iFd < 0)
+	    return _error->Errno("open",_("Failed to write file %s"),
+				 Itm.Name);
+	 
+	 // fchmod deals with umask and fchown sets the ownership
+	 if (fchmod(iFd,Itm.Mode) != 0)
+	 {
+	    close(iFd);
+	    return _error->Errno("fchmod",_("Failed to write file %s"), Itm.Name);
+	 }
+	 if (fchown(iFd,Itm.UID,Itm.GID) != 0 && errno != EPERM)
+	 {
+	    close(iFd);
+	    return _error->Errno("fchown",_("Failed to write file %s"), Itm.Name);
+	 }
+	 Fd = iFd;
+	 return true;
+      }
+      
+      case Item::HardLink:
+      case Item::SymbolicLink:
+      case Item::CharDevice:
+      case Item::BlockDevice:
+      case Item::Directory:
+      {
+	 struct stat Buf;
+	 // check if the dir is already there, if so return true
+	 if (stat(Itm.Name,&Buf) == 0)
+	 {
+	    if(S_ISDIR(Buf.st_mode))
+	       return true;
+	    // something else is there already, return false
+	    return false;
+	 }
+	 // nothing here, create the dir
+	 if(mkdir(Itm.Name,Itm.Mode) < 0)
+	    return false;
+	 return true;
+      }
+      case Item::FIFO:
+      break;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// DirStream::FinishedFile - Finished processing a file			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgDirStream::FinishedFile(Item &Itm,int Fd)
+{
+   if (Fd < 0)
+      return true;
+
+   /* Set the modification times. The only way it can fail is if someone
+      has futzed with our file, which is intolerable :> */
+   struct timeval times[2];
+   times[0].tv_sec = times[1].tv_sec = Itm.MTime;
+   times[0].tv_usec = times[1].tv_usec = 0;
+   if (utimes(Itm.Name, times) != 0)
+      _error->Errno("utimes", "Failed to set modification time for %s",Itm.Name);
+
+   if (close(Fd) != 0)
+      return _error->Errno("close",_("Failed to close file %s"),Itm.Name);
+   return true;
+}
+									/*}}}*/
+// DirStream::Fail - Failed processing a file				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgDirStream::Fail(Item &/*Itm*/, int Fd)
+{
+   if (Fd < 0)
+      return true;
+   
+   close(Fd);
+   return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/dirstream.h b/apt-pkg/dirstream.h
new file mode 100644
index 0000000..e5b226e
--- /dev/null
+++ b/apt-pkg/dirstream.h
@@ -0,0 +1,57 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Directory Stream 
+
+   When unpacking the contents of the archive are passed into a directory
+   stream class for analysis and processing. The class controls all aspects
+   of actually writing the directory stream from disk. The low level
+   archive handlers are only responsible for decoding the archive format
+   and sending events (via method calls) to the specified directory
+   stream.
+   
+   When unpacking a real file the archive handler is passed back a file 
+   handle to write the data to, this is to support strange 
+   archives+unpacking methods. If that fd is -1 then the file data is 
+   simply ignored.
+   
+   The provided defaults do the 'Right Thing' for a normal unpacking
+   process (ie 'tar')
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_DIRSTREAM_H
+#define PKGLIB_DIRSTREAM_H
+
+#include <apt-pkg/macros.h>
+
+class APT_PUBLIC pkgDirStream
+{ 
+   public:
+
+   // All possible information about a component
+   struct Item
+   {
+      enum Type_t {File, HardLink, SymbolicLink, CharDevice, BlockDevice,
+	           Directory, FIFO} Type;
+      char *Name;
+      char *LinkTarget;
+      unsigned long Mode;
+      unsigned long UID;
+      unsigned long GID;
+      unsigned long long Size;
+      unsigned long MTime;
+      unsigned long Major;
+      unsigned long Minor;
+   };
+   
+   virtual bool DoItem(Item &Itm,int &Fd);
+   virtual bool Fail(Item &Itm,int Fd);
+   virtual bool FinishedFile(Item &Itm,int Fd);
+   virtual bool Process(Item &/*Itm*/,const unsigned char * /*Data*/,
+			unsigned long long /*Size*/,unsigned long long /*Pos*/) {return true;};
+   virtual ~pkgDirStream() {};   
+};
+
+#endif
diff --git a/apt-pkg/edsp.cc b/apt-pkg/edsp.cc
new file mode 100644
index 0000000..9d196ee
--- /dev/null
+++ b/apt-pkg/edsp.cc
@@ -0,0 +1,1195 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   Set of methods to help writing and reading everything needed for EDSP
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/edsp.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/prettyprinters.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile.h>
+
+#include <ctype.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <array>
+#include <limits>
+#include <sstream>
+#include <string>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+// we could use pkgCache::DepType and ::Priority, but these would be localized strings…
+constexpr char const * const PrioMap[] = {
+   nullptr, "important", "required", "standard",
+   "optional", "extra"
+};
+constexpr char const * const DepMap[] = {
+   nullptr, "Depends", "Pre-Depends", "Suggests",
+   "Recommends" , "Conflicts", "Replaces",
+   "Obsoletes", "Breaks", "Enhances"
+};
+
+// WriteOkay - varaidic helper to easily Write to a FileFd		/*{{{*/
+static bool WriteOkay_fn(FileFd &) { return true; }
+template<typename... Tail> static bool WriteOkay_fn(FileFd &output, APT::StringView data, Tail... more_data)
+{
+   return likely(output.Write(data.data(), data.length()) && WriteOkay_fn(output, more_data...));
+}
+template<typename... Tail> static bool WriteOkay_fn(FileFd &output, unsigned int data, Tail... more_data)
+{
+   std::string number;
+   strprintf(number, "%d", data);
+   return likely(output.Write(number.data(), number.length()) && WriteOkay_fn(output, more_data...));
+}
+template<typename... Data> static bool WriteOkay(bool &Okay, FileFd &output, Data&&... data)
+{
+   Okay = likely(Okay && WriteOkay_fn(output, std::forward<Data>(data)...));
+   return Okay;
+}
+template<typename... Data> static bool WriteOkay(FileFd &output, Data&&... data)
+{
+   bool Okay = likely(output.Failed() == false);
+   return WriteOkay(Okay, output, std::forward<Data>(data)...);
+}
+									/*}}}*/
+// WriteScenarioVersion							/*{{{*/
+static bool WriteScenarioVersion(FileFd &output, pkgCache::PkgIterator const &Pkg,
+				pkgCache::VerIterator const &Ver)
+{
+   bool Okay = WriteOkay(output, "Package: ", Pkg.Name(),
+	 "\nArchitecture: ", Ver.Arch(),
+	 "\nVersion: ", Ver.VerStr());
+   WriteOkay(Okay, output, "\nAPT-ID: ", Ver->ID);
+   if (Ver.PhasedUpdatePercentage() != 100)
+      WriteOkay(Okay, output, "\nPhased-Update-Percentage: ", Ver.PhasedUpdatePercentage());
+   if ((Pkg->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+      WriteOkay(Okay, output, "\nEssential: yes");
+   if ((Ver->MultiArch & pkgCache::Version::Allowed) == pkgCache::Version::Allowed)
+      WriteOkay(Okay, output, "\nMulti-Arch: allowed");
+   else if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign)
+      WriteOkay(Okay, output, "\nMulti-Arch: foreign");
+   else if ((Ver->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+      WriteOkay(Okay, output, "\nMulti-Arch: same");
+   return Okay;
+}
+									/*}}}*/
+// WriteScenarioDependency						/*{{{*/
+static bool WriteScenarioDependency(FileFd &output, pkgCache::VerIterator const &Ver, bool const OnlyCritical)
+{
+   std::array<std::string, APT_ARRAY_SIZE(DepMap)> dependencies;
+   bool orGroup = false;
+   for (pkgCache::DepIterator Dep = Ver.DependsList(); Dep.end() == false; ++Dep)
+   {
+      if (Dep.IsImplicit() == true)
+	 continue;
+      if (OnlyCritical && Dep.IsCritical() == false)
+	 continue;
+      if (orGroup == false && dependencies[Dep->Type].empty() == false)
+	 dependencies[Dep->Type].append(", ");
+      dependencies[Dep->Type].append(Dep.TargetPkg().Name());
+      if (Dep->Version != 0)
+	 dependencies[Dep->Type].append(" (").append(pkgCache::CompTypeDeb(Dep->CompareOp)).append(" ").append(Dep.TargetVer()).append(")");
+      if ((Dep->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or)
+      {
+	 dependencies[Dep->Type].append(" | ");
+	 orGroup = true;
+      }
+      else
+	 orGroup = false;
+   }
+   bool Okay = output.Failed() == false;
+   for (size_t i = 1; i < dependencies.size(); ++i)
+      if (dependencies[i].empty() == false)
+	 WriteOkay(Okay, output, "\n", DepMap[i], ": ", dependencies[i]);
+   std::vector<std::string> provides;
+   for (auto Prv = Ver.ProvidesList(); not Prv.end(); ++Prv)
+   {
+      if (Prv.IsMultiArchImplicit())
+	 continue;
+      std::string provide = Prv.Name();
+      if (Prv->ProvideVersion != 0)
+	 provide.append(" (= ").append(Prv.ProvideVersion()).append(")");
+      if ((Ver->MultiArch & pkgCache::Version::Foreign) != 0 && std::find(provides.cbegin(), provides.cend(), provide) != provides.cend())
+	 continue;
+      provides.emplace_back(std::move(provide));
+   }
+   if (not provides.empty())
+   {
+      std::ostringstream out;
+      std::copy(provides.begin(), provides.end() - 1, std::ostream_iterator<std::string>(out, ", "));
+      out << provides.back();
+      WriteOkay(Okay, output, "\nProvides: ", out.str());
+   }
+   return WriteOkay(Okay, output, "\n");
+}
+									/*}}}*/
+// WriteScenarioLimitedDependency					/*{{{*/
+static bool WriteScenarioLimitedDependency(FileFd &output,
+					  pkgCache::VerIterator const &Ver,
+					  std::vector<bool> const &pkgset,
+					  bool const OnlyCritical)
+{
+   std::array<std::string, APT_ARRAY_SIZE(DepMap)> dependencies;
+   bool orGroup = false;
+   for (pkgCache::DepIterator Dep = Ver.DependsList(); Dep.end() == false; ++Dep)
+   {
+      if (Dep.IsImplicit() == true)
+	 continue;
+      if (OnlyCritical && Dep.IsCritical() == false)
+	 continue;
+      if (orGroup == false)
+      {
+	 if (pkgset[Dep.TargetPkg()->ID] == false)
+	    continue;
+	 if (dependencies[Dep->Type].empty() == false)
+	    dependencies[Dep->Type].append(", ");
+      }
+      else if (pkgset[Dep.TargetPkg()->ID] == false)
+      {
+	 if ((Dep->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or)
+	    continue;
+	 dependencies[Dep->Type].erase(dependencies[Dep->Type].end()-3, dependencies[Dep->Type].end());
+	 orGroup = false;
+	 continue;
+      }
+      dependencies[Dep->Type].append(Dep.TargetPkg().Name());
+      if (Dep->Version != 0)
+	 dependencies[Dep->Type].append(" (").append(pkgCache::CompTypeDeb(Dep->CompareOp)).append(" ").append(Dep.TargetVer()).append(")");
+      if ((Dep->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or)
+      {
+	 dependencies[Dep->Type].append(" | ");
+	 orGroup = true;
+      }
+      else
+	 orGroup = false;
+   }
+   bool Okay = output.Failed() == false;
+   for (size_t i = 1; i < dependencies.size(); ++i)
+      if (dependencies[i].empty() == false)
+	 WriteOkay(Okay, output, "\n", DepMap[i], ": ", dependencies[i]);
+   string provides;
+   for (pkgCache::PrvIterator Prv = Ver.ProvidesList(); Prv.end() == false; ++Prv)
+   {
+      if (Prv.IsMultiArchImplicit() == true)
+	 continue;
+      if (pkgset[Prv.ParentPkg()->ID] == false)
+	 continue;
+      if (provides.empty() == false)
+	 provides.append(", ");
+      provides.append(Prv.Name());
+      if (Prv->ProvideVersion != 0)
+	 provides.append(" (= ").append(Prv.ProvideVersion()).append(")");
+   }
+   if (provides.empty() == false)
+      WriteOkay(Okay, output, "\nProvides: ", provides);
+   return WriteOkay(Okay, output, "\n");
+}
+									/*}}}*/
+static bool checkKnownArchitecture(std::string const &arch)		/*{{{*/
+{
+   if (APT::Configuration::checkArchitecture(arch))
+      return true;
+   static auto const veryforeign = _config->FindVector("APT::BarbarianArchitectures");
+   return std::find(veryforeign.begin(), veryforeign.end(), arch) != veryforeign.end();
+}
+									/*}}}*/
+static bool WriteGenericRequestHeaders(FileFd &output, APT::StringView const head)/*{{{*/
+{
+   bool Okay = WriteOkay(output, head, "Architecture: ", _config->Find("APT::Architecture"), "\n",
+	 "Architectures:");
+   for (auto const &a : APT::Configuration::getArchitectures())
+       WriteOkay(Okay, output, " ", a);
+   for (auto const &a : _config->FindVector("APT::BarbarianArchitectures"))
+       WriteOkay(Okay, output, " ", a);
+   return WriteOkay(Okay, output, "\n");
+}
+									/*}}}*/
+static bool SkipUnavailableVersions(pkgDepCache &Cache, pkgCache::PkgIterator const &Pkg, pkgCache::VerIterator const &Ver)/*{{{*/
+{
+   /* versions which aren't current and aren't available in
+      any "online" source file are bad, expect if they are the chosen
+      candidate: The exception is for build-dep implementation as it creates
+      such pseudo (package) versions and removes them later on again.
+      We filter out versions at all so packages in 'rc' state only available
+      in dpkg/status aren't passed to solvers as they can't be installed. */
+   if (Pkg->CurrentVer != 0)
+      return false;
+   if (Cache.GetCandidateVersion(Pkg) == Ver)
+      return false;
+   for (pkgCache::VerFileIterator I = Ver.FileList(); I.end() == false; ++I)
+      if (I.File().Flagged(pkgCache::Flag::NotSource) == false)
+	 return false;
+   return true;
+}
+									/*}}}*/
+static bool WriteScenarioEDSPVersion(pkgDepCache &Cache, FileFd &output, pkgCache::PkgIterator const &Pkg,/*{{{*/
+				pkgCache::VerIterator const &Ver)
+{
+   bool Okay = WriteOkay(output, "\nSource: ", Ver.SourcePkgName(),
+	 "\nSource-Version: ", Ver.SourceVerStr());
+   if (PrioMap[Ver->Priority] != nullptr)
+      WriteOkay(Okay, output, "\nPriority: ", PrioMap[Ver->Priority]);
+   if (Ver->Section != 0)
+      WriteOkay(Okay, output, "\nSection: ", Ver.Section());
+   if (Pkg.CurrentVer() == Ver)
+      WriteOkay(Okay, output, "\nInstalled: yes");
+   if (Pkg->SelectedState == pkgCache::State::Hold ||
+       (Cache[Pkg].Keep() == true && Cache[Pkg].Protect() == true))
+      WriteOkay(Okay, output, "\nHold: yes");
+   std::set<string> Releases;
+   for (pkgCache::VerFileIterator I = Ver.FileList(); I.end() == false; ++I) {
+      pkgCache::PkgFileIterator File = I.File();
+      if (File.Flagged(pkgCache::Flag::NotSource) == false) {
+	 string Release = File.RelStr();
+	 if (!Release.empty())
+	    Releases.insert(Release);
+      }
+   }
+   if (!Releases.empty()) {
+       WriteOkay(Okay, output, "\nAPT-Release:");
+       for (std::set<string>::iterator R = Releases.begin(); R != Releases.end(); ++R)
+	   WriteOkay(Okay, output, "\n ", *R);
+   }
+   WriteOkay(Okay, output, "\nAPT-Pin: ", Cache.GetPolicy().GetPriority(Ver));
+   if (Cache.GetCandidateVersion(Pkg) == Ver)
+      WriteOkay(Okay, output, "\nAPT-Candidate: yes");
+   if ((Cache[Pkg].Flags & pkgCache::Flag::Auto) == pkgCache::Flag::Auto)
+      WriteOkay(Okay, output, "\nAPT-Automatic: yes");
+   return Okay;
+}
+									/*}}}*/
+// EDSP::WriteScenario - to the given file descriptor			/*{{{*/
+bool EDSP::WriteScenario(pkgDepCache &Cache, FileFd &output, OpProgress *Progress)
+{
+   if (Progress != NULL)
+      Progress->SubProgress(Cache.Head().VersionCount, _("Send scenario to solver"));
+   decltype(Cache.Head().VersionCount) p = 0;
+   bool Okay = output.Failed() == false;
+   for (pkgCache::PkgIterator Pkg = Cache.PkgBegin(); Pkg.end() == false && likely(Okay); ++Pkg)
+   {
+      if (Pkg->CurrentVer == 0 && not checkKnownArchitecture(Pkg.Arch()))
+	 continue;
+      for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false && likely(Okay); ++Ver, ++p)
+      {
+	 if (SkipUnavailableVersions(Cache, Pkg, Ver))
+	    continue;
+	 Okay &= WriteScenarioVersion(output, Pkg, Ver);
+	 Okay &= WriteScenarioEDSPVersion(Cache, output, Pkg, Ver);
+	 Okay &= WriteScenarioDependency(output, Ver, false);
+	 WriteOkay(Okay, output, "\n");
+	 if (Progress != NULL && p % 100 == 0)
+	    Progress->Progress(p);
+      }
+   }
+   return Okay;
+}
+									/*}}}*/
+// EDSP::WriteLimitedScenario - to the given file descriptor		/*{{{*/
+bool EDSP::WriteLimitedScenario(pkgDepCache &Cache, FileFd &output,
+				std::vector<bool> const &pkgset,
+				OpProgress *Progress)
+{
+   if (Progress != NULL)
+      Progress->SubProgress(Cache.Head().VersionCount, _("Send scenario to solver"));
+   decltype(Cache.Head().PackageCount) p = 0;
+   bool Okay = output.Failed() == false;
+   for (auto Pkg = Cache.PkgBegin(); Pkg.end() == false && likely(Okay); ++Pkg, ++p)
+   {
+      if (pkgset[Pkg->ID] == false)
+	 continue;
+      for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false && likely(Okay); ++Ver)
+      {
+	 if (SkipUnavailableVersions(Cache, Pkg, Ver))
+	    continue;
+	 Okay &= WriteScenarioVersion(output, Pkg, Ver);
+	 Okay &= WriteScenarioEDSPVersion(Cache, output, Pkg, Ver);
+	 Okay &= WriteScenarioLimitedDependency(output, Ver, pkgset, false);
+	 WriteOkay(Okay, output, "\n");
+	 if (Progress != NULL && p % 100 == 0)
+	    Progress->Progress(p);
+      }
+   }
+   if (Progress != NULL)
+      Progress->Done();
+   return Okay;
+}
+									/*}}}*/
+// EDSP::WriteRequest - to the given file descriptor			/*{{{*/
+bool EDSP::WriteRequest(pkgDepCache &Cache, FileFd &output,
+			unsigned int const flags,
+			OpProgress *Progress)
+{
+   if (Progress != NULL)
+      Progress->SubProgress(Cache.Head().PackageCount, _("Send request to solver"));
+   decltype(Cache.Head().PackageCount) p = 0;
+   string del, inst;
+   for (pkgCache::PkgIterator Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg, ++p)
+   {
+      if (Progress != NULL && p % 100 == 0)
+         Progress->Progress(p);
+      string* req;
+      pkgDepCache::StateCache &P = Cache[Pkg];
+      if (P.Delete() == true)
+	 req = &del;
+      else if (P.NewInstall() == true || P.Upgrade() == true || P.ReInstall() == true ||
+	       (P.Mode == pkgDepCache::ModeKeep && (P.iFlags & pkgDepCache::Protected) == pkgDepCache::Protected))
+	 req = &inst;
+      else
+	 continue;
+      req->append(" ").append(Pkg.FullName());
+   }
+
+   bool Okay = WriteGenericRequestHeaders(output, "Request: EDSP 0.5\n");
+   string machineID = APT::Configuration::getMachineID();
+   if (not machineID.empty())
+      WriteOkay(Okay, output, "Machine-ID: ", machineID, "\n");
+   if (del.empty() == false)
+      WriteOkay(Okay, output, "Remove:", del, "\n");
+   if (inst.empty() == false)
+      WriteOkay(Okay, output, "Install:", inst, "\n");
+   if (flags & Request::AUTOREMOVE)
+      WriteOkay(Okay, output, "Autoremove: yes\n");
+   if (flags & Request::UPGRADE_ALL)
+   {
+      WriteOkay(Okay, output, "Upgrade-All: yes\n");
+      if (flags & (Request::FORBID_NEW_INSTALL | Request::FORBID_REMOVE))
+	 WriteOkay(Okay, output, "Upgrade: yes\n");
+      else
+	 WriteOkay(Okay, output, "Dist-Upgrade: yes\n");
+   }
+   if (flags & Request::FORBID_NEW_INSTALL)
+      WriteOkay(Okay, output, "Forbid-New-Install: yes\n");
+   if (flags & Request::FORBID_REMOVE)
+      WriteOkay(Okay, output, "Forbid-Remove: yes\n");
+   auto const solver = _config->Find("APT::Solver", "internal");
+   WriteOkay(Okay, output, "Solver: ", solver, "\n");
+   if (_config->FindB("APT::Solver::Strict-Pinning", true) == false)
+      WriteOkay(Okay, output, "Strict-Pinning: no\n");
+   string solverpref("APT::Solver::");
+   solverpref.append(solver).append("::Preferences");
+   if (_config->Exists(solverpref) == true)
+      WriteOkay(Okay, output, "Preferences: ", _config->Find(solverpref,""), "\n");
+   return WriteOkay(Okay, output, "\n");
+}
+									/*}}}*/
+// EDSP::ReadResponse - from the given file descriptor			/*{{{*/
+bool EDSP::ReadResponse(int const input, pkgDepCache &Cache, OpProgress *Progress) {
+	/* We build an map id to mmap offset here
+	   In theory we could use the offset as ID, but then VersionCount
+	   couldn't be used to create other versionmappings anymore and it
+	   would be too easy for a (buggy) solver to segfault APT… */
+	auto VersionCount = Cache.Head().VersionCount;
+	decltype(VersionCount) VerIdx[VersionCount];
+	for (pkgCache::PkgIterator P = Cache.PkgBegin(); P.end() == false; ++P) {
+		for (pkgCache::VerIterator V = P.VersionList(); V.end() == false; ++V)
+			VerIdx[V->ID] = V.Index();
+		Cache[P].Marked = true;
+		Cache[P].Garbage = false;
+	}
+
+	FileFd in;
+	in.OpenDescriptor(input, FileFd::ReadOnly, true);
+	pkgTagFile response(&in, 100);
+	pkgTagSection section;
+
+	std::set<decltype(Cache.PkgBegin()->ID)> seenOnce;
+	while (response.Step(section) == true) {
+		std::string type;
+		if (section.Exists("Install") == true)
+			type = "Install";
+		else if (section.Exists("Remove") == true)
+			type = "Remove";
+		else if (section.Exists("Progress") == true) {
+			if (Progress != NULL) {
+				string msg = section.FindS("Message");
+				if (msg.empty() == true)
+					msg = _("Prepare for receiving solution");
+				Progress->SubProgress(100, msg, section.FindI("Percentage", 0));
+			}
+			continue;
+		} else if (section.Exists("Error") == true) {
+			if (_error->PendingError()) {
+				if (Progress != nullptr)
+					Progress->Done();
+				Progress = nullptr;
+				_error->DumpErrors(std::cerr, GlobalError::DEBUG, false);
+			}
+			std::string msg = SubstVar(SubstVar(section.FindS("Message"), "\n .\n", "\n\n"), "\n ", "\n");
+			if (msg.empty() == true) {
+				msg = _("External solver failed without a proper error message");
+				_error->Error("%s", msg.c_str());
+			} else
+				_error->Error("External solver failed with: %s", msg.substr(0,msg.find('\n')).c_str());
+			if (Progress != nullptr)
+				Progress->Done();
+			std::cerr << "The solver encountered an error of type: " << section.FindS("Error") << std::endl;
+			std::cerr << "The following information might help you to understand what is wrong:" << std::endl;
+			std::cerr << msg << std::endl << std::endl;
+			return false;
+		} else if (section.Exists("Autoremove") == true)
+			type = "Autoremove";
+		else {
+			char const *Start, *End;
+			section.GetSection(Start, End);
+			_error->Warning("Encountered an unexpected section with %d fields: %s", section.Count(), std::string(Start, End).c_str());
+			continue;
+		}
+
+		decltype(VersionCount) const id = section.FindULL(type, VersionCount);
+		if (id == VersionCount) {
+			_error->Warning("Unable to parse %s request with id value '%s'!", type.c_str(), section.FindS(type.c_str()).c_str());
+			continue;
+		} else if (id > VersionCount) {
+			_error->Warning("ID value '%s' in %s request stanza is to high to refer to a known version!", section.FindS(type.c_str()).c_str(), type.c_str());
+			continue;
+		}
+
+		pkgCache::VerIterator Ver(Cache.GetCache(), Cache.GetCache().VerP + VerIdx[id]);
+		auto const Pkg = Ver.ParentPkg();
+		if (type == "Autoremove") {
+			Cache[Pkg].Marked = false;
+			Cache[Pkg].Garbage = true;
+		} else if (seenOnce.emplace(Pkg->ID).second == false) {
+			_error->Warning("Ignoring %s stanza received for package %s which already had a previous stanza effecting it!", type.c_str(), Pkg.FullName(false).c_str());
+		} else if (type == "Install") {
+			if (Pkg.CurrentVer() == Ver) {
+				_error->Warning("Ignoring Install stanza received for version %s of package %s which is already installed!",
+				      Ver.VerStr(), Pkg.FullName(false).c_str());
+			} else {
+				Cache.SetCandidateVersion(Ver);
+				Cache.MarkInstall(Pkg, false, 0, false);
+			}
+		} else if (type == "Remove") {
+			if (Pkg->CurrentVer == 0)
+				_error->Warning("Ignoring Remove stanza received for version %s of package %s which isn't installed!",
+				      Ver.VerStr(), Pkg.FullName(false).c_str());
+			else if (Pkg.CurrentVer() != Ver)
+				_error->Warning("Ignoring Remove stanza received for version %s of package %s which isn't the installed version %s!",
+				      Ver.VerStr(), Pkg.FullName(false).c_str(), Pkg.CurrentVer().VerStr());
+			else
+				Cache.MarkDelete(Ver.ParentPkg(), false);
+		}
+	}
+	return true;
+}
+									/*}}}*/
+// ReadLine - first line from the given file descriptor			/*{{{*/
+// ---------------------------------------------------------------------
+/* Little helper method to read a complete line into a string. Similar to
+   fgets but we need to use the low-level read() here as otherwise the
+   listparser will be confused later on as mixing of fgets and read isn't
+   a supported action according to the manpages and results are undefined */
+static bool ReadLine(int const input, std::string &line) {
+	char one;
+	ssize_t data = 0;
+	line.erase();
+	line.reserve(100);
+	while ((data = read(input, &one, sizeof(one))) != -1) {
+		if (data != 1)
+			continue;
+		if (one == '\n')
+			return true;
+		if (one == '\r')
+			continue;
+		if (line.empty() == true && isblank(one) != 0)
+			continue;
+		line += one;
+	}
+	return false;
+}
+									/*}}}*/
+// StringToBool - convert yes/no to bool				/*{{{*/
+// ---------------------------------------------------------------------
+/* we are not as lazy as we are in the global StringToBool as we really
+   only accept yes/no here */
+static bool localStringToBool(std::string answer, bool const defValue) {
+   std::transform(answer.begin(), answer.end(), answer.begin(), ::tolower);
+   if (answer == "yes")
+      return true;
+   else if (answer == "no")
+      return false;
+   else
+      _error->Warning("Value '%s' is not a boolean 'yes' or 'no'!", answer.c_str());
+   return defValue;
+}
+									/*}}}*/
+static bool LineStartsWithAndStrip(std::string &line, APT::StringView const with)/*{{{*/
+{
+   if (line.compare(0, with.size(), with.data()) != 0)
+      return false;
+   line = APT::String::Strip(line.substr(with.length()));
+   return true;
+}
+									/*}}}*/
+static bool ReadFlag(unsigned int &flags, std::string &line, APT::StringView const name, unsigned int const setflag)/*{{{*/
+{
+   if (LineStartsWithAndStrip(line, name) == false)
+      return false;
+   if (localStringToBool(line, false))
+      flags |= setflag;
+   else
+      flags &= ~setflag;
+   return true;
+}
+									/*}}}*/
+// EDSP::ReadRequest - first stanza from the given file descriptor	/*{{{*/
+bool EDSP::ReadRequest(int const input, std::list<std::string> &install,
+			std::list<std::string> &remove, unsigned int &flags)
+{
+   install.clear();
+   remove.clear();
+   flags = 0;
+   std::string line;
+   while (ReadLine(input, line) == true)
+   {
+      // Skip empty lines before request
+      if (line.empty() == true)
+	 continue;
+      // The first Tag must be a request, so search for it
+      if (LineStartsWithAndStrip(line, "Request:"))
+	 continue;
+
+      while (ReadLine(input, line) == true)
+      {
+	 // empty lines are the end of the request
+	 if (line.empty() == true)
+	    return true;
+
+	 std::list<std::string> *request = NULL;
+	 if (LineStartsWithAndStrip(line, "Install:"))
+	    request = &install;
+	 else if (LineStartsWithAndStrip(line, "Remove:"))
+	    request = &remove;
+	 else if (ReadFlag(flags, line, "Upgrade:", (Request::UPGRADE_ALL | Request::FORBID_REMOVE | Request::FORBID_NEW_INSTALL)) ||
+	       ReadFlag(flags, line, "Dist-Upgrade:", Request::UPGRADE_ALL) ||
+	       ReadFlag(flags, line, "Upgrade-All:", Request::UPGRADE_ALL) ||
+	       ReadFlag(flags, line, "Forbid-New-Install:", Request::FORBID_NEW_INSTALL) ||
+	       ReadFlag(flags, line, "Forbid-Remove:", Request::FORBID_REMOVE) ||
+	       ReadFlag(flags, line, "Autoremove:", Request::AUTOREMOVE))
+	    ;
+	 else if (LineStartsWithAndStrip(line, "Architecture:"))
+	    _config->Set("APT::Architecture", line);
+	 else if (LineStartsWithAndStrip(line, "Architectures:"))
+	    _config->Set("APT::Architectures", SubstVar(line, " ", ","));
+	 else if (LineStartsWithAndStrip(line, "Machine-ID"))
+	    _config->Set("APT::Machine-ID", line);
+	 else if (LineStartsWithAndStrip(line, "Solver:"))
+	    ; // purely informational line
+	 else
+	    _error->Warning("Unknown line in EDSP Request stanza: %s", line.c_str());
+
+	 if (request == NULL)
+	    continue;
+	 auto const pkgs = VectorizeString(line, ' ');
+	 std::move(pkgs.begin(), pkgs.end(), std::back_inserter(*request));
+      }
+   }
+   return false;
+}									/*}}}*/
+// EDSP::ApplyRequest - first stanza from the given file descriptor	/*{{{*/
+bool EDSP::ApplyRequest(std::list<std::string> const &install,
+			 std::list<std::string> const &remove,
+			 pkgDepCache &Cache)
+{
+	for (std::list<std::string>::const_iterator i = install.begin();
+	     i != install.end(); ++i) {
+		pkgCache::PkgIterator P = Cache.FindPkg(*i);
+		if (P.end() == true)
+			_error->Warning("Package %s is not known, so can't be installed", i->c_str());
+		else
+			Cache.MarkInstall(P, false);
+	}
+
+	for (std::list<std::string>::const_iterator i = remove.begin();
+	     i != remove.end(); ++i) {
+		pkgCache::PkgIterator P = Cache.FindPkg(*i);
+		if (P.end() == true)
+			_error->Warning("Package %s is not known, so can't be installed", i->c_str());
+		else
+			Cache.MarkDelete(P);
+	}
+	return true;
+}
+									/*}}}*/
+// EDSP::WriteSolutionStanza - to the given file descriptor		/*{{{*/
+bool EDSP::WriteSolutionStanza(FileFd &output, char const * const Type, pkgCache::VerIterator const &Ver)
+{
+   bool Okay = output.Failed() == false;
+   WriteOkay(Okay, output, Type, ": ", _system->GetVersionMapping(Ver->ID));
+   if (_config->FindB("Debug::EDSP::WriteSolution", false) == true)
+      WriteOkay(Okay, output, "\nPackage: ", Ver.ParentPkg().FullName(), "\nVersion: ", Ver.VerStr());
+   return WriteOkay(Okay, output, "\n\n");
+}
+									/*}}}*/
+// EDSP::WriteProgess - pulse to the given file descriptor		/*{{{*/
+bool EDSP::WriteProgress(unsigned short const percent, const char* const message, FileFd &output) {
+	return WriteOkay(output, "Progress: ", TimeRFC1123(time(NULL), true), "\n",
+	      "Percentage: ", percent, "\n",
+	      "Message: ", message, "\n\n") && output.Flush();
+}
+									/*}}}*/
+// EDSP::WriteError - format an error message to be send to file descriptor /*{{{*/
+static std::string formatMessage(std::string const &msg)
+{
+	return SubstVar(SubstVar(APT::String::Strip(msg), "\n\n", "\n.\n"), "\n", "\n ");
+}
+bool EDSP::WriteError(char const * const uuid, std::string const &message, FileFd &output) {
+	return WriteOkay(output, "Error: ", uuid, "\n",
+	      "Message: ", formatMessage(message),
+	      "\n\n");
+}
+									/*}}}*/
+static std::string findExecutable(std::vector<std::string> const &dirs, char const * const binary) {/*{{{*/
+	for (auto && dir : dirs) {
+		std::string const file = flCombine(dir, binary);
+		if (RealFileExists(file) == true)
+			return file;
+	}
+	return "";
+}
+									/*}}}*/
+static pid_t ExecuteExternal(char const* const type, char const * const binary, char const * const configdir, int * const solver_in, int * const solver_out) {/*{{{*/
+	auto const solverDirs = _config->FindVector(configdir);
+	auto const file = findExecutable(solverDirs, binary);
+	std::string dumper;
+	{
+		dumper = findExecutable(solverDirs, "apt-dump-solver");
+		if (dumper.empty())
+			dumper = findExecutable(solverDirs, "dump");
+	}
+
+	if (file.empty() == true)
+	{
+		_error->Error("Can't call external %s '%s' as it is not in a configured directory!", type, binary);
+		return 0;
+	}
+	int external[4] = {-1, -1, -1, -1};
+	if (pipe(external) != 0 || pipe(external + 2) != 0)
+	{
+		_error->Errno("Resolve", "Can't create needed IPC pipes for EDSP");
+		return 0;
+	}
+	for (int i = 0; i < 4; ++i)
+		SetCloseExec(external[i], true);
+
+	pid_t Solver = ExecFork();
+	if (Solver == 0) {
+		dup2(external[0], STDIN_FILENO);
+		dup2(external[3], STDOUT_FILENO);
+		auto const dumpfile = _config->FindFile((std::string("Dir::Log::") + type).c_str());
+		auto const dumpdir = flNotFile(dumpfile);
+		auto const runasuser = _config->Find(std::string("APT::") + type + "::" + binary + "::RunAsUser",
+		      _config->Find(std::string("APT::") + type + "::RunAsUser",
+			 _config->Find("APT::Sandbox::User")));
+		if (dumper.empty() || dumpfile.empty() || dumper == file || CreateAPTDirectoryIfNeeded(dumpdir, dumpdir) == false)
+		{
+		   _config->Set("APT::Sandbox::User", runasuser);
+		   DropPrivileges();
+		   char const * const calling[] = { file.c_str(), nullptr };
+		   execv(calling[0], const_cast<char**>(calling));
+		}
+		else
+		{
+		   char const * const calling[] = { dumper.c_str(), "--user", runasuser.c_str(), dumpfile.c_str(), file.c_str(), nullptr };
+		   execv(calling[0], const_cast<char**>(calling));
+		}
+		std::cerr << "Failed to execute " << type << " '" << binary << "'!" << std::endl;
+		_exit(100);
+	}
+	close(external[0]);
+	close(external[3]);
+
+	if (WaitFd(external[1], true, 5) == false)
+	{
+		_error->Errno("Resolve", "Timed out while Waiting on availability of %s stdin", type);
+		return 0;
+	}
+
+	*solver_in = external[1];
+	*solver_out = external[2];
+	return Solver;
+}
+									/*}}}*/
+// EDSP::ExecuteSolver - fork requested solver and setup ipc pipes	{{{*/
+pid_t EDSP::ExecuteSolver(const char* const solver, int * const solver_in, int * const solver_out, bool) {
+	return ExecuteExternal("solver", solver, "Dir::Bin::Solvers", solver_in, solver_out);
+}
+									/*}}}*/
+static bool CreateDumpFile(char const * const id, char const * const type, FileFd &output)/*{{{*/
+{
+	auto const dumpfile = _config->FindFile((std::string("Dir::Log::") + type).c_str());
+	if (dumpfile.empty())
+		return false;
+	auto const dumpdir = flNotFile(dumpfile);
+	_error->PushToStack();
+	bool errored_out = CreateAPTDirectoryIfNeeded(dumpdir, dumpdir) == false ||
+	   output.Open(dumpfile, FileFd::WriteOnly | FileFd::Exclusive | FileFd::Create, FileFd::Extension, 0644) == false;
+	std::vector<std::string> downgrademsgs;
+	while (_error->empty() == false)
+	{
+		std::string msg;
+		_error->PopMessage(msg);
+		downgrademsgs.emplace_back(std::move(msg));
+	}
+	_error->RevertToStack();
+	for (auto && msg : downgrademsgs)
+	   _error->Warning("%s", msg.c_str());
+	if (errored_out)
+		return _error->WarningE(id, _("Could not open file '%s'"), dumpfile.c_str());
+	return true;
+}
+									/*}}}*/
+// EDSP::ResolveExternal - resolve problems by asking external for help	{{{*/
+bool EDSP::ResolveExternal(const char* const solver, pkgDepCache &Cache,
+			 unsigned int const flags, OpProgress *Progress) {
+	if (strcmp(solver, "internal") == 0)
+	{
+		FileFd output;
+		bool Okay = CreateDumpFile("EDSP::Resolve", "solver", output);
+		Okay &= EDSP::WriteRequest(Cache, output, flags, nullptr);
+		return Okay && EDSP::WriteScenario(Cache, output, nullptr);
+	}
+	_error->PushToStack();
+	int solver_in, solver_out;
+	pid_t const solver_pid = ExecuteSolver(solver, &solver_in, &solver_out, true);
+	if (solver_pid == 0)
+		return false;
+
+	FileFd output;
+	if (output.OpenDescriptor(solver_in, FileFd::WriteOnly | FileFd::BufferedWrite, true) == false)
+		return _error->Errno("ResolveExternal", "Opening solver %s stdin on fd %d for writing failed", solver, solver_in);
+
+	bool Okay = output.Failed() == false;
+	if (Okay && Progress != NULL)
+		Progress->OverallProgress(0, 100, 5, _("Execute external solver"));
+	Okay &= EDSP::WriteRequest(Cache, output, flags, Progress);
+	if (Okay && Progress != NULL)
+		Progress->OverallProgress(5, 100, 20, _("Execute external solver"));
+	Okay &= EDSP::WriteScenario(Cache, output, Progress);
+	output.Close();
+
+	if (Okay && Progress != NULL)
+		Progress->OverallProgress(25, 100, 75, _("Execute external solver"));
+	bool const ret = EDSP::ReadResponse(solver_out, Cache, Progress);
+	_error->MergeWithStack();
+	if (ExecWait(solver_pid, solver))
+		return ret;
+	return false;
+}									/*}}}*/
+
+bool EIPP::OrderInstall(char const * const solver, pkgPackageManager * const PM,	/*{{{*/
+			 unsigned int const flags, OpProgress * const Progress)
+{
+   if (strcmp(solver, "internal") == 0)
+   {
+      FileFd output;
+      _error->PushToStack();
+      bool Okay = CreateDumpFile("EIPP::OrderInstall", "planner", output);
+      if (Okay == false && dynamic_cast<pkgSimulate*>(PM) != nullptr)
+      {
+	 _error->RevertToStack();
+	 return false;
+      }
+      _error->MergeWithStack();
+      Okay &= EIPP::WriteRequest(PM->Cache, output, flags, nullptr);
+      return Okay && EIPP::WriteScenario(PM->Cache, output, nullptr);
+   }
+   _error->PushToStack();
+   int solver_in, solver_out;
+   pid_t const solver_pid = ExecuteExternal("planner", solver, "Dir::Bin::Planners", &solver_in, &solver_out);
+   if (solver_pid == 0)
+      return false;
+
+   FileFd output;
+   if (output.OpenDescriptor(solver_in, FileFd::WriteOnly | FileFd::BufferedWrite, true) == false)
+      return _error->Errno("EIPP::OrderInstall", "Opening planner %s stdin on fd %d for writing failed", solver, solver_in);
+
+   bool Okay = output.Failed() == false;
+   if (Okay && Progress != NULL)
+      Progress->OverallProgress(0, 100, 5, _("Execute external planner"));
+   Okay &= EIPP::WriteRequest(PM->Cache, output, flags, Progress);
+   if (Okay && Progress != NULL)
+      Progress->OverallProgress(5, 100, 20, _("Execute external planner"));
+   Okay &= EIPP::WriteScenario(PM->Cache, output, Progress);
+   output.Close();
+
+   if (Okay)
+   {
+      if (Progress != nullptr)
+	 Progress->OverallProgress(25, 100, 75, _("Execute external planner"));
+
+      // we don't tell the external planners about boring things
+      for (auto Pkg = PM->Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+      {
+	 if (Pkg->CurrentState == pkgCache::State::ConfigFiles && PM->Cache[Pkg].Purge() == true)
+	    PM->Remove(Pkg, true);
+      }
+   }
+   bool const ret = EIPP::ReadResponse(solver_out, PM, Progress);
+   _error->MergeWithStack();
+   if (ExecWait(solver_pid, solver))
+      return ret;
+   return false;
+}
+									/*}}}*/
+bool EIPP::WriteRequest(pkgDepCache &Cache, FileFd &output,		/*{{{*/
+			unsigned int const flags,
+			OpProgress * const Progress)
+{
+   if (Progress != NULL)
+      Progress->SubProgress(Cache.Head().PackageCount, _("Send request to planner"));
+   decltype(Cache.Head().PackageCount) p = 0;
+   string del, inst, reinst;
+   for (pkgCache::PkgIterator Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg, ++p)
+   {
+      if (Progress != NULL && p % 100 == 0)
+         Progress->Progress(p);
+      string* req;
+      pkgDepCache::StateCache &P = Cache[Pkg];
+      if (P.Purge() == true && Pkg->CurrentState == pkgCache::State::ConfigFiles)
+	 continue;
+      if (P.Delete() == true)
+	 req = &del;
+      else if (P.NewInstall() == true || P.Upgrade() == true || P.Downgrade() == true)
+	 req = &inst;
+      else if (P.ReInstall() == true)
+	 req = &reinst;
+      else
+	 continue;
+      req->append(" ").append(Pkg.FullName());
+   }
+
+   bool Okay = WriteGenericRequestHeaders(output, "Request: EIPP 0.1\n");
+   if (del.empty() == false)
+      WriteOkay(Okay, output, "Remove:", del, "\n");
+   if (inst.empty() == false)
+      WriteOkay(Okay, output, "Install:", inst, "\n");
+   if (reinst.empty() == false)
+      WriteOkay(Okay, output, "ReInstall:", reinst, "\n");
+   WriteOkay(Okay, output, "Planner: ", _config->Find("APT::Planner", "internal"), "\n");
+   if ((flags & Request::IMMEDIATE_CONFIGURATION_ALL) != 0)
+      WriteOkay(Okay, output, "Immediate-Configuration: yes\n");
+   else if ((flags & Request::NO_IMMEDIATE_CONFIGURATION) != 0)
+      WriteOkay(Okay, output, "Immediate-Configuration: no\n");
+   else if ((flags & Request::ALLOW_TEMPORARY_REMOVE_OF_ESSENTIALS) != 0)
+      WriteOkay(Okay, output, "Allow-Temporary-Remove-of-Essentials: yes\n");
+   return WriteOkay(Okay, output, "\n");
+}
+									/*}}}*/
+static bool WriteScenarioEIPPVersion(pkgDepCache &, FileFd &output, pkgCache::PkgIterator const &Pkg,/*{{{*/
+				pkgCache::VerIterator const &Ver)
+{
+   bool Okay = true;
+   if (Pkg.CurrentVer() == Ver)
+      switch (Pkg->CurrentState)
+      {
+	 case pkgCache::State::NotInstalled: WriteOkay(Okay, output, "\nStatus: not-installed"); break;
+	 case pkgCache::State::ConfigFiles: WriteOkay(Okay, output, "\nStatus: config-files"); break;
+	 case pkgCache::State::HalfInstalled: WriteOkay(Okay, output, "\nStatus: half-installed"); break;
+	 case pkgCache::State::UnPacked: WriteOkay(Okay, output, "\nStatus: unpacked"); break;
+	 case pkgCache::State::HalfConfigured: WriteOkay(Okay, output, "\nStatus: half-configured"); break;
+	 case pkgCache::State::TriggersAwaited: WriteOkay(Okay, output, "\nStatus: triggers-awaited"); break;
+	 case pkgCache::State::TriggersPending: WriteOkay(Okay, output, "\nStatus: triggers-pending"); break;
+	 case pkgCache::State::Installed: WriteOkay(Okay, output, "\nStatus: installed"); break;
+      }
+   return Okay;
+}
+									/*}}}*/
+// EIPP::WriteScenario - to the given file descriptor			/*{{{*/
+template<typename forVersion> void forAllInterestingVersions(pkgDepCache &Cache, pkgCache::PkgIterator const &Pkg, forVersion const &func)
+{
+   if (Pkg->CurrentState == pkgCache::State::NotInstalled)
+   {
+      auto P = Cache[Pkg];
+      if (P.Install() == false)
+	 return;
+      func(Pkg, P.InstVerIter(Cache));
+   }
+   else
+   {
+      if (Pkg->CurrentVer != 0)
+	 func(Pkg, Pkg.CurrentVer());
+      auto P = Cache[Pkg];
+      auto const V = P.InstVerIter(Cache);
+      if (P.Delete() == false && Pkg.CurrentVer() != V)
+	 func(Pkg, V);
+   }
+}
+
+bool EIPP::WriteScenario(pkgDepCache &Cache, FileFd &output, OpProgress * const Progress)
+{
+   if (Progress != NULL)
+      Progress->SubProgress(Cache.Head().PackageCount, _("Send scenario to planner"));
+   decltype(Cache.Head().PackageCount) p = 0;
+   bool Okay = output.Failed() == false;
+   std::vector<bool> pkgset(Cache.Head().PackageCount, false);
+   auto const MarkVersion = [&](pkgCache::PkgIterator const &Pkg, pkgCache::VerIterator const &Ver) {
+      pkgset[Pkg->ID] = true;
+      for (auto D = Ver.DependsList(); D.end() == false; ++D)
+      {
+	 if (D.IsCritical() == false)
+	    continue;
+	 auto const P = D.TargetPkg();
+	 for (auto Prv = P.ProvidesList(); Prv.end() == false; ++Prv)
+	 {
+	    auto const V = Prv.OwnerVer();
+	    auto const PV = V.ParentPkg();
+	    if (V == PV.CurrentVer() || V == Cache[PV].InstVerIter(Cache))
+	       pkgset[PV->ID] = true;
+	 }
+	 pkgset[P->ID] = true;
+	 if (strcmp(P.Arch(), "any") == 0)
+	 {
+	    APT::StringView const pkgname(P.Name());
+	    auto const idxColon = pkgname.find(':');
+	    if (idxColon != APT::StringView::npos)
+	    {
+	       pkgCache::PkgIterator PA;
+	       if (pkgname.substr(idxColon + 1) == "any")
+	       {
+		  auto const GA = Cache.FindGrp(pkgname.substr(0, idxColon).to_string());
+		  for (auto PA = GA.PackageList(); PA.end() == false; PA = GA.NextPkg(PA))
+		  {
+		     pkgset[PA->ID] = true;
+		  }
+	       }
+	       else
+	       {
+		  auto const PA = Cache.FindPkg(pkgname.to_string());
+		  if (PA.end() == false)
+		     pkgset[PA->ID] = true;
+	       }
+	    }
+	 }
+	 else
+	 {
+	    auto const PA = Cache.FindPkg(P.FullName(false), "any");
+	    if (PA.end() == false)
+	       pkgset[PA->ID] = true;
+	 }
+      }
+   };
+   for (pkgCache::PkgIterator Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+      forAllInterestingVersions(Cache, Pkg, MarkVersion);
+   auto const WriteVersion = [&](pkgCache::PkgIterator const &Pkg, pkgCache::VerIterator const &Ver) {
+      Okay &= WriteScenarioVersion(output, Pkg, Ver);
+      Okay &= WriteScenarioEIPPVersion(Cache, output, Pkg, Ver);
+      Okay &= WriteScenarioLimitedDependency(output, Ver, pkgset, true);
+      WriteOkay(Okay, output, "\n");
+      if (Progress != NULL && p % 100 == 0)
+	 Progress->Progress(p);
+   };
+   for (pkgCache::PkgIterator Pkg = Cache.PkgBegin(); Pkg.end() == false && likely(Okay); ++Pkg, ++p)
+   {
+      if (pkgset[Pkg->ID] == false || Pkg->VersionList == 0)
+	 continue;
+      forAllInterestingVersions(Cache, Pkg, WriteVersion);
+   }
+   return Okay;
+}
+									/*}}}*/
+// EIPP::ReadResponse - from the given file descriptor			/*{{{*/
+bool EIPP::ReadResponse(int const input, pkgPackageManager * const PM, OpProgress *Progress) {
+   /* We build an map id to mmap offset here
+      In theory we could use the offset as ID, but then VersionCount
+      couldn't be used to create other versionmappings anymore and it
+      would be too easy for a (buggy) solver to segfault APT… */
+   auto VersionCount = PM->Cache.Head().VersionCount;
+   decltype(VersionCount) VerIdx[VersionCount];
+   for (pkgCache::PkgIterator P = PM->Cache.PkgBegin(); P.end() == false; ++P) {
+      for (pkgCache::VerIterator V = P.VersionList(); V.end() == false; ++V)
+	 VerIdx[V->ID] = V.Index();
+   }
+
+   FileFd in;
+   in.OpenDescriptor(input, FileFd::ReadOnly);
+   pkgTagFile response(&in, 100);
+   pkgTagSection section;
+
+   while (response.Step(section) == true) {
+      char const * type = nullptr;
+      if (section.Exists("Progress") == true) {
+	 if (Progress != NULL) {
+	    string msg = section.FindS("Message");
+	    if (msg.empty() == true)
+	       msg = _("Prepare for receiving solution");
+	    Progress->SubProgress(100, msg, section.FindI("Percentage", 0));
+	 }
+	 continue;
+      } else if (section.Exists("Error") == true) {
+	 if (_error->PendingError()) {
+	    if (Progress != nullptr)
+	       Progress->Done();
+	    Progress = nullptr;
+	    _error->DumpErrors(std::cerr, GlobalError::DEBUG, false);
+	 }
+	 std::string msg = SubstVar(SubstVar(section.FindS("Message"), "\n .\n", "\n\n"), "\n ", "\n");
+	 if (msg.empty() == true) {
+	    msg = _("External planner failed without a proper error message");
+	    _error->Error("%s", msg.c_str());
+	 } else
+	    _error->Error("External planner failed with: %s", msg.substr(0,msg.find('\n')).c_str());
+	 if (Progress != nullptr)
+	    Progress->Done();
+	 std::cerr << "The planner encountered an error of type: " << section.FindS("Error") << std::endl;
+	 std::cerr << "The following information might help you to understand what is wrong:" << std::endl;
+	 std::cerr << msg << std::endl << std::endl;
+	 return false;
+      } else if (section.Exists("Unpack") == true)
+	 type = "Unpack";
+      else if (section.Exists("Configure") == true)
+	 type = "Configure";
+      else if (section.Exists("Remove") == true)
+	 type = "Remove";
+      else {
+	 char const *Start, *End;
+	 section.GetSection(Start, End);
+	 _error->Warning("Encountered an unexpected section with %d fields: %s", section.Count(), std::string(Start, End).c_str());
+	 continue;
+      }
+
+      if (type == nullptr)
+	 continue;
+      decltype(VersionCount) const id = section.FindULL(type, VersionCount);
+      if (id == VersionCount) {
+	 _error->Warning("Unable to parse %s request with id value '%s'!", type, section.FindS(type).c_str());
+	 continue;
+      } else if (id > VersionCount) {
+	 _error->Warning("ID value '%s' in %s request stanza is to high to refer to a known version!", section.FindS(type).c_str(), type);
+	 continue;
+      }
+
+      pkgCache::VerIterator Ver(PM->Cache.GetCache(), PM->Cache.GetCache().VerP + VerIdx[id]);
+      auto const Pkg = Ver.ParentPkg();
+      if (strcmp(type, "Unpack") == 0)
+	 PM->Install(Pkg, PM->FileNames[Pkg->ID]);
+      else if (strcmp(type, "Configure") == 0)
+	 PM->Configure(Pkg);
+      else if (strcmp(type, "Remove") == 0)
+	 PM->Remove(Pkg, PM->Cache[Pkg].Purge());
+   }
+   return in.Failed() == false;
+}
+									/*}}}*/
+bool EIPP::ReadRequest(int const input, std::list<std::pair<std::string,PKG_ACTION>> &actions,/*{{{*/
+      unsigned int &flags)
+{
+   actions.clear();
+   flags = 0;
+   std::string line;
+   while (ReadLine(input, line) == true)
+   {
+      // Skip empty lines before request
+      if (line.empty() == true)
+	 continue;
+      // The first Tag must be a request, so search for it
+      if (line.compare(0, 8, "Request:") != 0)
+	 continue;
+
+      while (ReadLine(input, line) == true)
+      {
+	 // empty lines are the end of the request
+	 if (line.empty() == true)
+	    return true;
+
+	 PKG_ACTION pkgact = PKG_ACTION::NOOP;
+	 if (LineStartsWithAndStrip(line, "Install:"))
+	    pkgact = PKG_ACTION::INSTALL;
+	 else if (LineStartsWithAndStrip(line, "ReInstall:"))
+	    pkgact = PKG_ACTION::REINSTALL;
+	 else if (LineStartsWithAndStrip(line, "Remove:"))
+	    pkgact = PKG_ACTION::REMOVE;
+	 else if (LineStartsWithAndStrip(line, "Architecture:"))
+	    _config->Set("APT::Architecture", line);
+	 else if (LineStartsWithAndStrip(line, "Architectures:"))
+	    _config->Set("APT::Architectures", SubstVar(line, " ", ","));
+	 else if (LineStartsWithAndStrip(line, "Planner:"))
+	    ; // purely informational line
+	 else if (LineStartsWithAndStrip(line, "Immediate-Configuration:"))
+	 {
+	    if (localStringToBool(line, true))
+	       flags |= Request::IMMEDIATE_CONFIGURATION_ALL;
+	    else
+	       flags |= Request::NO_IMMEDIATE_CONFIGURATION;
+	 }
+	 else if (ReadFlag(flags, line, "Allow-Temporary-Remove-of-Essentials:", Request::ALLOW_TEMPORARY_REMOVE_OF_ESSENTIALS))
+	    ;
+	 else
+	    _error->Warning("Unknown line in EIPP Request stanza: %s", line.c_str());
+
+	 if (pkgact == PKG_ACTION::NOOP)
+	    continue;
+	 for (auto && p: VectorizeString(line, ' '))
+	    actions.emplace_back(std::move(p), pkgact);
+      }
+   }
+   return false;
+}
+									/*}}}*/
+bool EIPP::ApplyRequest(std::list<std::pair<std::string,PKG_ACTION>> &actions,/*{{{*/
+	 pkgDepCache &Cache)
+{
+   for (auto Pkg = Cache.PkgBegin(); Pkg.end() == false; ++Pkg)
+   {
+      short versions = 0;
+      for (auto Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
+      {
+	 ++versions;
+	 if (Pkg.CurrentVer() == Ver)
+	    continue;
+	 Cache.SetCandidateVersion(Ver);
+      }
+      if (unlikely(versions > 2))
+	 _error->Warning("Package %s has %d versions, but should have at most 2!", Pkg.FullName().c_str(), versions);
+   }
+   for (auto && a: actions)
+   {
+      pkgCache::PkgIterator P = Cache.FindPkg(a.first);
+      if (P.end() == true)
+      {
+	 _error->Warning("Package %s is not known, so can't be acted on", a.first.c_str());
+	 continue;
+      }
+      switch (a.second)
+      {
+	 case PKG_ACTION::NOOP:
+	    _error->Warning("Package %s has NOOP as action?!?", a.first.c_str());
+	    break;
+	 case PKG_ACTION::INSTALL:
+	    Cache.MarkInstall(P, false);
+	    break;
+	 case PKG_ACTION::REINSTALL:
+	    Cache.MarkInstall(P, false);
+	    Cache.SetReInstall(P, true);
+	    break;
+	 case PKG_ACTION::REMOVE:
+	    Cache.MarkDelete(P);
+	    break;
+      }
+   }
+   return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/edsp.h b/apt-pkg/edsp.h
new file mode 100644
index 0000000..434010d
--- /dev/null
+++ b/apt-pkg/edsp.h
@@ -0,0 +1,252 @@
+// -*- mode: cpp; mode: fold -*-
+/** Description \file edsp.h						{{{
+   ######################################################################
+   Set of methods to help writing and reading everything needed for EDSP
+   with the notable exception of reading a scenario for conversion into
+   a Cache as this is handled by edsp interface for listparser and friends
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EDSP_H
+#define PKGLIB_EDSP_H
+
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <stdio.h>
+
+#include <list>
+#include <string>
+#include <vector>
+
+
+class pkgDepCache;
+class OpProgress;
+
+namespace EDSP								/*{{{*/
+{
+	namespace Request
+	{
+	   enum Flags
+	   {
+	      AUTOREMOVE = (1 << 0), /*!< removal of unneeded packages should be performed */
+	      UPGRADE_ALL = (1 << 1), /*!< upgrade all installed packages, like 'apt-get full-upgrade' without forbid flags */
+	      FORBID_NEW_INSTALL = (1 << 2), /*!< forbid the resolver to install new packages */
+	      FORBID_REMOVE = (1 << 3), /*!< forbid the resolver to remove packages */
+	   };
+	}
+	/** \brief creates the EDSP request stanza
+	 *
+	 *  In the EDSP protocol the first thing send to the resolver is a stanza
+	 *  encoding the request. This method will write this stanza by looking at
+	 *  the given Cache and requests the installation of all packages which were
+	 *  marked for installation in it (equally for remove).
+	 *
+	 *  \param Cache in which the request is encoded
+	 *  \param output is written to this "file"
+	 *  \param flags effecting the request documented in #EDSP::Request::Flags
+	 *  \param Progress is an instance to report progress to
+	 *
+	 *  \return true if request was composed successfully, otherwise false
+	 */
+	APT_PUBLIC bool WriteRequest(pkgDepCache &Cache, FileFd &output,
+				 unsigned int const flags = 0,
+				OpProgress *Progress = NULL);
+
+	/** \brief creates the scenario representing the package universe
+	 *
+	 *  After the request all known information about a package are send
+	 *  to the solver. The output looks similar to a Packages or status file
+	 *
+	 *  All packages and version included in this Cache are send, even if
+	 *  it doesn't make sense from an APT resolver point of view like versions
+	 *  with a negative pin to enable the solver to propose even that as a
+	 *  solution or at least to be able to give a hint what can be done to
+	 *  satisfy a request.
+	 *
+	 *  \param Cache is the known package universe
+	 *  \param output is written to this "file"
+	 *  \param Progress is an instance to report progress to
+	 *
+	 *  \return true if universe was composed successfully, otherwise false
+	 */
+	APT_PUBLIC bool WriteScenario(pkgDepCache &Cache, FileFd &output, OpProgress *Progress = NULL);
+
+	/** \brief creates a limited scenario representing the package universe
+	 *
+	 *  This method works similar to #WriteScenario as it works in the same
+	 *  way but doesn't send the complete universe to the solver but only
+	 *  packages included in the pkgset which will have only dependencies
+	 *  on packages which are in the given set. All other dependencies will
+	 *  be removed, so that this method can be used to create testcases
+	 *
+	 *  \param Cache is the known package universe
+	 *  \param output is written to this "file"
+	 *  \param pkgset is a set of packages the universe should be limited to
+	 *  \param Progress is an instance to report progress to
+	 *
+	 *  \return true if universe was composed successfully, otherwise false
+	 */
+	APT_PUBLIC bool WriteLimitedScenario(pkgDepCache &Cache, FileFd &output,
+					 std::vector<bool> const &pkgset,
+					 OpProgress *Progress = NULL);
+
+	/** \brief waits and acts on the information returned from the solver
+	 *
+	 *  This method takes care of interpreting whatever the solver sends
+	 *  through the standard output like a solution, progress or an error.
+	 *  The main thread should hand his control over to this method to
+	 *  wait for the solver to finish the given task. The file descriptor
+	 *  used as input is completely consumed and closed by the method.
+	 *
+	 *  \param input file descriptor with the response from the solver
+	 *  \param Cache the solution should be applied on if any
+	 *  \param Progress is an instance to report progress to
+	 *
+	 *  \return true if a solution is found and applied correctly, otherwise false
+	 */
+	APT_PUBLIC bool ReadResponse(int const input, pkgDepCache &Cache, OpProgress *Progress = NULL);
+
+	/** \brief search and read the request stanza for action later
+	 *
+	 *  This method while ignore the input up to the point it finds the
+	 *  Request: line as an indicator for the Request stanza.
+	 *  The request is stored in the parameters install and remove then,
+	 *  as the cache isn't build yet as the scenario follows the request.
+	 *
+	 *  \param input file descriptor with the edsp input for the solver
+	 *  \param[out] install is a list which gets populated with requested installs
+	 *  \param[out] remove is a list which gets populated with requested removals
+	 *  \param[out] upgrade is true if it is a request like apt-get upgrade
+	 *  \param[out] distUpgrade is true if it is a request like apt-get dist-upgrade
+	 *  \param[out] autoRemove is true if removal of unneeded packages should be performed
+	 *
+	 *  \return true if the request could be found and worked on, otherwise false
+	 */
+	APT_PUBLIC bool ReadRequest(int const input, std::list<std::string> &install,
+			std::list<std::string> &remove, unsigned int &flags);
+
+	/** \brief takes the request lists and applies it on the cache
+	 *
+	 *  The lists as created by #ReadRequest will be used to find the
+	 *  packages in question and mark them for install/remove.
+	 *  No solving is done and no auto-install/-remove.
+	 *
+	 *  \param install is a list of packages to mark for installation
+	 *  \param remove is a list of packages to mark for removal
+	 *  \param Cache is there the markers should be set
+	 *
+	 *  \return false if the request couldn't be applied, true otherwise
+	 */
+	APT_PUBLIC bool ApplyRequest(std::list<std::string> const &install,
+				 std::list<std::string> const &remove,
+				 pkgDepCache &Cache);
+
+	/** \brief formats a solution stanza for the given version
+	 *
+	 *  EDSP uses a simple format for reporting solutions:
+	 *  A single required field name with an ID as value.
+	 *  Additional fields might appear as debug aids.
+	 *
+	 *  \param output to write the stanza forming the solution to
+	 *  \param Type of the stanza, used as field name
+	 *  \param Ver this stanza applies to
+	 *
+	 *  \return true if stanza could be written, otherwise false
+	 */
+	APT_PUBLIC bool WriteSolutionStanza(FileFd &output, char const * const Type, pkgCache::VerIterator const &Ver);
+
+	/** \brief sends a progress report
+	 *
+	 *  \param percent of the solving completed
+	 *  \param message the solver wants the user to see
+	 *  \param output the front-end listens for progress report
+	 */
+	APT_PUBLIC bool WriteProgress(unsigned short const percent, const char* const message, FileFd &output);
+
+	/** \brief sends an error report
+	 *
+	 *  Solvers are expected to execute successfully even if
+	 *  they were unable to calculate a solution for a given task.
+	 *  Obviously they can't send a solution through, so this
+	 *  methods deals with formatting an error message correctly
+	 *  so that the front-ends can receive and display it.
+	 *
+	 *  The first line of the message should be a short description
+	 *  of the error so it can be used for dialog titles or alike
+	 *
+	 *  \param uuid of this error message
+	 *  \param message is free form text to describe the error
+	 *  \param output the front-end listens for error messages
+	 */
+	APT_PUBLIC bool WriteError(char const * const uuid, std::string const &message, FileFd &output);
+
+
+	/** \brief executes the given solver and returns the pipe ends
+	 *
+	 *  The given solver is executed if it can be found in one of the
+	 *  configured directories and setup for it is performed.
+	 *
+	 *  \param solver to execute
+	 *  \param[out] solver_in will be the stdin of the solver
+	 *  \param[out] solver_out will be the stdout of the solver
+	 *
+	 *  \return PID of the started solver or 0 if failure occurred
+	 */
+	APT_PUBLIC pid_t ExecuteSolver(const char* const solver, int * const solver_in, int * const solver_out, bool /*overload*/);
+
+	/** \brief call an external resolver to handle the request
+	 *
+	 *  This method wraps all the methods above to call an external solver
+	 *
+	 *  \param solver to execute
+	 *  \param Cache with the problem and as universe to work in
+	 *  \param flags effecting the request documented in #EDSP::Request::Flags
+	 *  \param Progress is an instance to report progress to
+	 *
+	 *  \return true if the solver has successfully solved the problem,
+	 *  otherwise false
+	 */
+	APT_PUBLIC bool ResolveExternal(const char* const solver, pkgDepCache &Cache,
+				    unsigned int const flags = 0,
+				    OpProgress *Progress = NULL);
+}
+									/*}}}*/
+class pkgPackageManager;
+namespace EIPP								/*{{{*/
+{
+   namespace Request
+   {
+      enum Flags
+      {
+	 IMMEDIATE_CONFIGURATION_ALL = (1 << 0), /*!< try to keep the least amount of packages unconfigured as possible at all times */
+	 NO_IMMEDIATE_CONFIGURATION = (1 << 1), /*!< do not perform immediate configuration at all */
+	 ALLOW_TEMPORARY_REMOVE_OF_ESSENTIALS = (1 << 2), /*!< just as the name suggests, very special case and dangerous! */
+      };
+   }
+
+   APT_HIDDEN bool WriteRequest(pkgDepCache &Cache, FileFd &output,
+	 unsigned int const flags, OpProgress * const Progress);
+   APT_HIDDEN bool WriteScenario(pkgDepCache &Cache, FileFd &output,
+	 OpProgress * const Progress);
+
+   APT_HIDDEN bool OrderInstall(char const * const planner, pkgPackageManager * const PM,
+	 unsigned int const version, OpProgress * const Progress);
+   APT_HIDDEN bool ReadResponse(int const input, pkgPackageManager * const PM,
+	 OpProgress * const Progress);
+
+   enum class PKG_ACTION
+   {
+      NOOP,
+      INSTALL,
+      REINSTALL,
+      REMOVE
+   };
+   APT_PUBLIC bool ReadRequest(int const input,
+	 std::list<std::pair<std::string,PKG_ACTION>> &actions,
+	 unsigned int &flags);
+   APT_PUBLIC bool ApplyRequest(std::list<std::pair<std::string,PKG_ACTION>> &actions,
+	 pkgDepCache &Cache);
+}
+									/*}}}*/
+#endif
diff --git a/apt-pkg/edsp/edspindexfile.cc b/apt-pkg/edsp/edspindexfile.cc
new file mode 100644
index 0000000..faade6e
--- /dev/null
+++ b/apt-pkg/edsp/edspindexfile.cc
@@ -0,0 +1,129 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   The scenario file is designed to work as an intermediate file between
+   APT and the resolver. Its on propose very similar to a dpkg status file
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/edspindexfile.h>
+#include <apt-pkg/edsplistparser.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+
+#include <memory>
+#include <string>
+#include <stddef.h>
+#include <unistd.h>
+									/*}}}*/
+
+// EDSP-like Index							/*{{{*/
+edspLikeIndex::edspLikeIndex(std::string const &File) : pkgDebianIndexRealFile(File, true)
+{
+}
+std::string edspLikeIndex::GetArchitecture() const
+{
+   return std::string();
+}
+bool edspLikeIndex::HasPackages() const
+{
+   return true;
+}
+bool edspLikeIndex::Exists() const
+{
+   return true;
+}
+uint8_t edspLikeIndex::GetIndexFlags() const
+{
+   return 0;
+}
+bool edspLikeIndex::OpenListFile(FileFd &Pkg, std::string const &FileName)
+{
+   if (FileName.empty() == false && FileName != "/nonexistent/stdin")
+      return pkgDebianIndexRealFile::OpenListFile(Pkg, FileName);
+   if (Pkg.OpenDescriptor(STDIN_FILENO, FileFd::ReadOnly) == false)
+      return _error->Error("Problem opening %s",FileName.c_str());
+   return true;
+}
+									/*}}}*/
+// EDSP Index								/*{{{*/
+edspIndex::edspIndex(std::string const &File) : edspLikeIndex(File)
+{
+}
+std::string edspIndex::GetComponent() const
+{
+   return "edsp";
+}
+pkgCacheListParser * edspIndex::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new edspListParser(&Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+									/*}}}*/
+// EIPP Index								/*{{{*/
+eippIndex::eippIndex(std::string const &File) : edspLikeIndex(File)
+{
+}
+std::string eippIndex::GetComponent() const
+{
+   return "eipp";
+}
+pkgCacheListParser * eippIndex::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new eippListParser(&Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+									/*}}}*/
+
+// Index File types for APT						/*{{{*/
+class APT_HIDDEN edspIFType: public pkgIndexFile::Type
+{
+   public:
+   virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &) const APT_OVERRIDE
+   {
+      // we don't have a record parser for this type as the file is not persistent
+      return NULL;
+   };
+   edspIFType() {Label = "EDSP scenario file";};
+};
+APT_HIDDEN edspIFType _apt_Edsp;
+const pkgIndexFile::Type *edspIndex::GetType() const
+{
+   return &_apt_Edsp;
+}
+
+class APT_HIDDEN eippIFType: public pkgIndexFile::Type
+{
+   public:
+   virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &) const APT_OVERRIDE
+   {
+      // we don't have a record parser for this type as the file is not persistent
+      return NULL;
+   };
+   eippIFType() {Label = "EIPP scenario file";};
+};
+APT_HIDDEN eippIFType _apt_Eipp;
+const pkgIndexFile::Type *eippIndex::GetType() const
+{
+   return &_apt_Eipp;
+}
+									/*}}}*/
+
+edspLikeIndex::~edspLikeIndex() {}
+edspIndex::~edspIndex() {}
+eippIndex::~eippIndex() {}
diff --git a/apt-pkg/edsp/edspindexfile.h b/apt-pkg/edsp/edspindexfile.h
new file mode 100644
index 0000000..42ef3fe
--- /dev/null
+++ b/apt-pkg/edsp/edspindexfile.h
@@ -0,0 +1,59 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   The scenario file is designed to work as an intermediate file between
+   APT and the resolver. Its on propose very similar to a dpkg status file
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EDSPINDEXFILE_H
+#define PKGLIB_EDSPINDEXFILE_H
+
+#include <apt-pkg/debindexfile.h>
+#include <string>
+
+
+class OpProgress;
+class pkgCacheGenerator;
+
+class APT_HIDDEN edspLikeIndex : public pkgDebianIndexRealFile
+{
+protected:
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &File) APT_OVERRIDE;
+   virtual uint8_t GetIndexFlags() const APT_OVERRIDE;
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+
+public:
+   virtual bool Exists() const APT_OVERRIDE;
+   virtual bool HasPackages() const APT_OVERRIDE;
+
+   explicit edspLikeIndex(std::string const &File);
+   virtual ~edspLikeIndex();
+};
+
+class APT_HIDDEN edspIndex : public edspLikeIndex
+{
+protected:
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+   virtual std::string GetComponent() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   explicit edspIndex(std::string const &File);
+   virtual ~edspIndex();
+};
+
+class APT_HIDDEN eippIndex : public edspLikeIndex
+{
+protected:
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg) APT_OVERRIDE;
+   virtual std::string GetComponent() const APT_OVERRIDE;
+
+public:
+   virtual const Type *GetType() const APT_OVERRIDE APT_PURE;
+
+   explicit eippIndex(std::string const &File);
+   virtual ~eippIndex();
+};
+
+#endif
diff --git a/apt-pkg/edsp/edsplistparser.cc b/apt-pkg/edsp/edsplistparser.cc
new file mode 100644
index 0000000..5419069
--- /dev/null
+++ b/apt-pkg/edsp/edsplistparser.cc
@@ -0,0 +1,177 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Package Cache Generator - Generator for the cache structure.
+
+   This builds the cache structure from the abstract package list parser.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/edsplistparser.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <array>
+
+									/*}}}*/
+
+// ListParser::edspListParser - Constructor				/*{{{*/
+edspLikeListParser::edspLikeListParser(FileFd * const File) : debListParser(File)
+{
+}
+edspListParser::edspListParser(FileFd * const File) : edspLikeListParser(File)
+{
+   std::string const states = _config->FindFile("Dir::State::extended_states");
+   RemoveFile("edspListParserPrivate", states);
+   extendedstates.Open(states, FileFd::WriteOnly | FileFd::Create | FileFd::Exclusive, 0600);
+   std::string const prefs = _config->FindFile("Dir::Etc::preferences");
+   RemoveFile("edspListParserPrivate", prefs);
+   preferences.Open(prefs, FileFd::WriteOnly | FileFd::Create | FileFd::Exclusive, 0600);
+}
+									/*}}}*/
+// ListParser::NewVersion - Fill in the version structure		/*{{{*/
+bool edspLikeListParser::NewVersion(pkgCache::VerIterator &Ver)
+{
+   _system->SetVersionMapping(Ver->ID, Section.FindI("APT-ID", Ver->ID));
+   return debListParser::NewVersion(Ver);
+}
+									/*}}}*/
+// ListParser::Description - Return the description string		/*{{{*/
+// ---------------------------------------------------------------------
+/* Sorry, no description for the resolvers… */
+std::vector<std::string> edspLikeListParser::AvailableDescriptionLanguages()
+{
+   return {};
+}
+APT::StringView edspLikeListParser::Description_md5()
+{
+   return APT::StringView();
+}
+									/*}}}*/
+// ListParser::VersionHash - Compute a unique hash for this version	/*{{{*/
+uint32_t edspLikeListParser::VersionHash()
+{
+   if (Section.Exists("APT-ID") == true)
+      return Section.FindI("APT-ID");
+   return 0;
+}
+									/*}}}*/
+// ListParser::ParseStatus - Parse the status field			/*{{{*/
+// ---------------------------------------------------------------------
+/* The Status: line here is not a normal dpkg one but just one which tells
+   use if the package is installed or not, where missing means not. */
+bool edspListParser::ParseStatus(pkgCache::PkgIterator &Pkg,
+				pkgCache::VerIterator &Ver)
+{
+   unsigned long state = 0;
+   if (Section.FindFlag("Hold",state,pkgCache::State::Hold) == false)
+      return false;
+   if (state != 0)
+      Pkg->SelectedState = pkgCache::State::Hold;
+
+   state = 0;
+   if (Section.FindFlag("Installed",state,pkgCache::State::Installed) == false)
+      return false;
+   if (state != 0)
+   {
+      Pkg->CurrentState = pkgCache::State::Installed;
+      Pkg->CurrentVer = Ver.MapPointer();
+   }
+
+   if (Section.FindB("APT-Automatic", false))
+   {
+      std::string out;
+      strprintf(out, "Package: %s\nArchitecture: %s\nAuto-Installed: 1\n\n", Pkg.Name(), Pkg.Arch());
+      if (extendedstates.Write(out.c_str(), out.length()) == false)
+	 return false;
+   }
+
+   // FIXME: Using an overriding pin is wrong.
+   if (Section.FindB("APT-Candidate", false))
+   {
+      std::string out;
+      strprintf(out, "Package: %s\nPin: version %s\nPin-Priority: 9999\n\n", Pkg.FullName().c_str(), Ver.VerStr());
+      if (preferences.Write(out.c_str(), out.length()) == false)
+	 return false;
+   }
+
+   signed short const pinvalue = Section.FindI("APT-Pin", 500);
+   if (pinvalue != 500)
+   {
+      std::string out;
+      strprintf(out, "Package: %s\nPin: version %s\nPin-Priority: %d\n\n", Pkg.FullName().c_str(), Ver.VerStr(), pinvalue);
+      if (preferences.Write(out.c_str(), out.length()) == false)
+	 return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+
+// ListParser::eippListParser - Constructor				/*{{{*/
+eippListParser::eippListParser(FileFd *File) : edspLikeListParser(File)
+{
+}
+									/*}}}*/
+// ListParser::ParseStatus - Parse the status field			/*{{{*/
+// ---------------------------------------------------------------------
+/* The Status: line here is not a normal dpkg one but just one which tells
+   use if the package is installed or not, where missing means not. */
+bool eippListParser::ParseStatus(pkgCache::PkgIterator &Pkg,
+				pkgCache::VerIterator &Ver)
+{
+   // Process the flag field
+   static std::array<WordList, 8> const statusvalues = {{
+      {"not-installed",pkgCache::State::NotInstalled},
+      {"config-files",pkgCache::State::ConfigFiles},
+      {"half-installed",pkgCache::State::HalfInstalled},
+      {"unpacked",pkgCache::State::UnPacked},
+      {"half-configured",pkgCache::State::HalfConfigured},
+      {"triggers-awaited",pkgCache::State::TriggersAwaited},
+      {"triggers-pending",pkgCache::State::TriggersPending},
+      {"installed",pkgCache::State::Installed},
+   }};
+   auto const status = Section.Find(pkgTagSection::Key::Status);
+   if (not status.empty())
+   {
+      for (auto && sv: statusvalues)
+      {
+	 if (status != sv.Str)
+	    continue;
+	 Pkg->CurrentState = sv.Val;
+	 switch (Pkg->CurrentState)
+	 {
+	    case pkgCache::State::NotInstalled:
+	    case pkgCache::State::ConfigFiles:
+	       break;
+	    case pkgCache::State::HalfInstalled:
+	    case pkgCache::State::UnPacked:
+	    case pkgCache::State::HalfConfigured:
+	    case pkgCache::State::TriggersAwaited:
+	    case pkgCache::State::TriggersPending:
+	    case pkgCache::State::Installed:
+	       Pkg->CurrentVer = Ver.MapPointer();
+	       break;
+	 }
+	 break;
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+
+edspLikeListParser::~edspLikeListParser() {}
+edspListParser::~edspListParser() {}
+eippListParser::~eippListParser() {}
diff --git a/apt-pkg/edsp/edsplistparser.h b/apt-pkg/edsp/edsplistparser.h
new file mode 100644
index 0000000..41bfd1f
--- /dev/null
+++ b/apt-pkg/edsp/edsplistparser.h
@@ -0,0 +1,58 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   EDSP Package List Parser - This implements the abstract parser
+   interface for the APT specific intermediate format which is passed
+   to external resolvers
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EDSPLISTPARSER_H
+#define PKGLIB_EDSPLISTPARSER_H
+
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <string>
+
+
+namespace APT {
+   class StringView;
+}
+class APT_HIDDEN edspLikeListParser : public debListParser
+{
+   public:
+   virtual bool NewVersion(pkgCache::VerIterator &Ver) APT_OVERRIDE;
+   virtual std::vector<std::string> AvailableDescriptionLanguages() APT_OVERRIDE;
+   virtual APT::StringView Description_md5() APT_OVERRIDE;
+   virtual uint32_t VersionHash() APT_OVERRIDE;
+
+   explicit edspLikeListParser(FileFd *File);
+   virtual ~edspLikeListParser();
+};
+
+class APT_HIDDEN edspListParser : public edspLikeListParser
+{
+   FileFd extendedstates;
+   FileFd preferences;
+
+protected:
+   virtual bool ParseStatus(pkgCache::PkgIterator &Pkg,pkgCache::VerIterator &Ver) APT_OVERRIDE;
+
+public:
+   explicit edspListParser(FileFd *File);
+   virtual ~edspListParser();
+};
+
+class APT_HIDDEN eippListParser : public edspLikeListParser
+{
+protected:
+   virtual bool ParseStatus(pkgCache::PkgIterator &Pkg,pkgCache::VerIterator &Ver) APT_OVERRIDE;
+
+public:
+   explicit eippListParser(FileFd *File);
+   virtual ~eippListParser();
+};
+#endif
diff --git a/apt-pkg/edsp/edspsystem.cc b/apt-pkg/edsp/edspsystem.cc
new file mode 100644
index 0000000..c86f1ed
--- /dev/null
+++ b/apt-pkg/edsp/edspsystem.cc
@@ -0,0 +1,166 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   This system provides the abstraction to use the scenario file as the
+   only source of package information to be able to feed the created file
+   back to APT for its own consumption (eat your own dogfood).
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debversion.h>
+#include <apt-pkg/edspindexfile.h>
+#include <apt-pkg/edspsystem.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+									/*}}}*/
+
+// System::System - Constructor						/*{{{*/
+edspLikeSystem::edspLikeSystem(char const * const Label) : pkgSystem(Label, &debVS)
+{
+}
+edspSystem::edspSystem() : edspLikeSystem("Debian APT solver interface")
+{
+}
+eippSystem::eippSystem() : edspLikeSystem("Debian APT planner interface")
+{
+}
+									/*}}}*/
+// System::Lock - Get the lock						/*{{{*/
+bool edspLikeSystem::Lock(OpProgress *)
+{
+   return true;
+}
+									/*}}}*/
+// System::UnLock - Drop a lock						/*{{{*/
+bool edspLikeSystem::UnLock(bool /*NoErrors*/)
+{
+   return true;
+}
+									/*}}}*/
+// System::CreatePM - Create the underlying package manager		/*{{{*/
+// ---------------------------------------------------------------------
+/* we can't use edsp input as input for real installations - just a
+   simulation can work, but everything else will fail bigtime */
+pkgPackageManager *edspLikeSystem::CreatePM(pkgDepCache * /*Cache*/) const
+{
+   return nullptr;
+}
+									/*}}}*/
+// System::Initialize - Setup the configuration space..			/*{{{*/
+bool edspLikeSystem::Initialize(Configuration &Cnf)
+{
+   Cnf.Set("Dir::Log", "/dev/null");
+   // state is included completely in the input files
+   Cnf.Set("Dir::Etc::preferences", "/dev/null");
+   Cnf.Set("Dir::Etc::preferencesparts", "/dev/null");
+   Cnf.Set("Dir::State::status","/dev/null");
+   Cnf.Set("Dir::State::extended_states","/dev/null");
+   Cnf.Set("Dir::State::lists","/dev/null");
+   // do not store an mmap cache
+   Cnf.Set("Dir::Cache::pkgcache", "");
+   Cnf.Set("Dir::Cache::srcpkgcache", "");
+   // the protocols only propose actions, not do them
+   Cnf.Set("Debug::NoLocking", "true");
+   Cnf.Set("APT::Get::Simulate", "true");
+
+   StatusFile.reset(nullptr);
+   return true;
+}
+bool edspSystem::Initialize(Configuration &Cnf)
+{
+   if (edspLikeSystem::Initialize(Cnf) == false)
+      return false;
+   std::string const tmp = GetTempDir();
+   char tmpname[300];
+   snprintf(tmpname, sizeof(tmpname), "%s/apt-edsp-solver-XXXXXX", tmp.c_str());
+   if (nullptr == mkdtemp(tmpname))
+      return false;
+   tempDir = tmpname;
+   tempStatesFile = flCombine(tempDir, "extended_states");
+   Cnf.Set("Dir::State::extended_states", tempStatesFile);
+   tempPrefsFile = flCombine(tempDir, "apt_preferences");
+   Cnf.Set("Dir::Etc::preferences", tempPrefsFile);
+   return true;
+}
+									/*}}}*/
+// System::ArchiveSupported - Is a file format supported		/*{{{*/
+bool edspLikeSystem::ArchiveSupported(const char * /*Type*/)
+{
+   return false;
+}
+									/*}}}*/
+// System::Score - Never use the EDSP system automatically		/*{{{*/
+signed edspLikeSystem::Score(Configuration const &)
+{
+   return -1000;
+}
+									/*}}}*/
+// System::FindIndex - Get an index file for status files		/*{{{*/
+bool edspLikeSystem::FindIndex(pkgCache::PkgFileIterator File,
+			  pkgIndexFile *&Found) const
+{
+   if (StatusFile == 0)
+      return false;
+   if (StatusFile->FindInCache(*File.Cache()) == File)
+   {
+      Found = StatusFile.get();
+      return true;
+   }
+
+   return false;
+}
+									/*}}}*/
+bool edspSystem::AddStatusFiles(std::vector<pkgIndexFile *> &List)	/*{{{*/
+{
+   if (StatusFile == nullptr)
+   {
+      if (_config->Find("edsp::scenario", "") == "/nonexistent/stdin")
+	 StatusFile.reset(new edspIndex("/nonexistent/stdin"));
+      else
+	 StatusFile.reset(new edspIndex(_config->FindFile("edsp::scenario")));
+   }
+   List.push_back(StatusFile.get());
+   return true;
+}
+									/*}}}*/
+bool eippSystem::AddStatusFiles(std::vector<pkgIndexFile *> &List)	/*{{{*/
+{
+   if (StatusFile == nullptr)
+   {
+      if (_config->Find("eipp::scenario", "") == "/nonexistent/stdin")
+	 StatusFile.reset(new eippIndex("/nonexistent/stdin"));
+      else
+	 StatusFile.reset(new eippIndex(_config->FindFile("eipp::scenario")));
+   }
+   List.push_back(StatusFile.get());
+   return true;
+}
+									/*}}}*/
+
+edspLikeSystem::~edspLikeSystem() {}
+edspSystem::~edspSystem()
+{
+   if (tempDir.empty())
+      return;
+
+   RemoveFile("~edspSystem", tempStatesFile);
+   RemoveFile("~edspSystem", tempPrefsFile);
+   rmdir(tempDir.c_str());
+}
+eippSystem::~eippSystem() {}
+
+APT_HIDDEN edspSystem edspSys;
+APT_HIDDEN eippSystem eippSys;
diff --git a/apt-pkg/edsp/edspsystem.h b/apt-pkg/edsp/edspsystem.h
new file mode 100644
index 0000000..97c2d66
--- /dev/null
+++ b/apt-pkg/edsp/edspsystem.h
@@ -0,0 +1,75 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   System - Debian version of the  System Class
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EDSPSYSTEM_H
+#define PKGLIB_EDSPSYSTEM_H
+
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/error.h>
+
+#include <memory>
+#include <vector>
+
+#include <apt-pkg/macros.h>
+
+class Configuration;
+class pkgDepCache;
+class pkgIndexFile;
+class pkgPackageManager;
+
+class APT_HIDDEN edspLikeSystem : public pkgSystem
+{
+protected:
+   std::unique_ptr<pkgIndexFile> StatusFile;
+
+public:
+   virtual bool Lock(OpProgress * const Progress) APT_OVERRIDE APT_PURE;
+   virtual bool UnLock(bool NoErrors = false) APT_OVERRIDE APT_PURE;
+   virtual pkgPackageManager *CreatePM(pkgDepCache *Cache) const APT_OVERRIDE APT_PURE;
+   virtual bool Initialize(Configuration &Cnf) APT_OVERRIDE;
+   virtual bool ArchiveSupported(const char *Type) APT_OVERRIDE APT_PURE;
+   virtual signed Score(Configuration const &Cnf) APT_OVERRIDE;
+   virtual bool FindIndex(pkgCache::PkgFileIterator File,
+			  pkgIndexFile *&Found) const APT_OVERRIDE;
+
+   bool MultiArchSupported() const override { return true; }
+   std::vector<std::string> ArchitecturesSupported() const override { return {}; };
+
+   bool LockInner(OpProgress * const, int) override { return _error->Error("LockInner is not implemented"); };
+   bool UnLockInner(bool) override { return _error->Error("UnLockInner is not implemented"); };
+   bool IsLocked() override { return true; };
+
+   explicit edspLikeSystem(char const * const Label);
+   virtual ~edspLikeSystem();
+};
+
+class APT_HIDDEN edspSystem : public edspLikeSystem
+{
+   std::string tempDir;
+   std::string tempStatesFile;
+   std::string tempPrefsFile;
+
+public:
+   virtual bool Initialize(Configuration &Cnf) APT_OVERRIDE;
+   virtual bool AddStatusFiles(std::vector<pkgIndexFile *> &List) APT_OVERRIDE;
+
+   edspSystem();
+   virtual ~edspSystem();
+};
+
+class APT_HIDDEN eippSystem : public edspLikeSystem
+{
+   public:
+   virtual bool AddStatusFiles(std::vector<pkgIndexFile *> &List) APT_OVERRIDE;
+
+   eippSystem();
+   virtual ~eippSystem();
+};
+
+#endif
diff --git a/apt-pkg/indexcopy.cc b/apt-pkg/indexcopy.cc
new file mode 100644
index 0000000..0d56926
--- /dev/null
+++ b/apt-pkg/indexcopy.cc
@@ -0,0 +1,775 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Index Copying - Aid for copying and verifying the index files
+   
+   This class helps apt-cache reconstruct a damaged index files. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cdrom.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debmetaindex.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <iostream>
+#include <sstream>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "indexcopy.h"
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// IndexCopy::CopyPackages - Copy the package files from the CD		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool IndexCopy::CopyPackages(string CDROM,string Name,vector<string> &List,
+			     pkgCdromStatus *log)
+{
+   OpProgress *Progress = NULL;
+   if (List.empty() == true)
+      return true;
+   
+   if(log) 
+      Progress = log->GetOpProgress();
+   
+   bool NoStat = _config->FindB("APT::CDROM::Fast",false);
+   bool Debug = _config->FindB("Debug::aptcdrom",false);
+   
+   // Prepare the progress indicator
+   off_t TotalSize = 0;
+   std::vector<APT::Configuration::Compressor> const compressor = APT::Configuration::getCompressors();
+   for (auto const &F : List)
+   {
+      struct stat Buf;
+      bool found = false;
+      auto const file = F + GetFileName();
+      for (auto const &c : compressor)
+      {
+	 if (stat((file + c.Extension).c_str(), &Buf) != 0)
+	    continue;
+	 found = true;
+	 break;
+      }
+
+      if (found == false)
+	 return _error->Errno("stat", "Stat failed for %s", file.c_str());
+      TotalSize += Buf.st_size;
+   }
+
+   off_t CurrentSize = 0;
+   unsigned int NotFound = 0;
+   unsigned int WrongSize = 0;
+   unsigned int Packages = 0;
+   for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      std::string OrigPath(*I,CDROM.length());
+
+      // Open the package file
+      FileFd Pkg(*I + GetFileName(), FileFd::ReadOnly, FileFd::Auto);
+      off_t const FileSize = Pkg.Size();
+
+      pkgTagFile Parser(&Pkg);
+      if (Pkg.IsOpen() == false || Pkg.Failed())
+	 return false;
+      
+      // Open the output file
+      char S[400];
+      snprintf(S,sizeof(S),"cdrom:[%s]/%s%s",Name.c_str(),
+	       (*I).c_str() + CDROM.length(),GetFileName());
+      string TargetF = _config->FindDir("Dir::State::lists") + "partial/";
+      TargetF += URItoFileName(S);
+      FileFd Target;
+      if (_config->FindB("APT::CDROM::NoAct",false) == true)
+      {
+	 TargetF = "/dev/null";
+         Target.Open(TargetF,FileFd::WriteExists);
+      } else {
+         Target.Open(TargetF,FileFd::WriteAtomic);
+      }
+      if (Target.IsOpen() == false || Target.Failed())
+	 return false;
+
+      // Setup the progress meter
+      if(Progress)
+	 Progress->OverallProgress(CurrentSize,TotalSize,FileSize,
+				   string("Reading ") + Type() + " Indexes");
+
+      // Parse
+      if(Progress)
+	 Progress->SubProgress(Pkg.Size());
+      pkgTagSection Section;
+      this->Section = &Section;
+      string Prefix;
+      unsigned long Hits = 0;
+      unsigned long Chop = 0;
+      while (Parser.Step(Section) == true)
+      {
+	 if(Progress)
+	    Progress->Progress(Parser.Offset());
+	 string File;
+	 unsigned long long Size;
+	 if (GetFile(File,Size) == false)
+	    return false;
+
+	 if (Chop != 0)
+	    File = OrigPath + ChopDirs(File,Chop);
+
+	 // See if the file exists
+	 if (NoStat == false || Hits < 10)
+	 {
+	    // Attempt to fix broken structure
+	    if (Hits == 0)
+	    {
+	       if (ReconstructPrefix(Prefix,OrigPath,CDROM,File) == false &&
+		   ReconstructChop(Chop,*I,File) == false)
+	       {
+		  if (Debug == true)
+		     clog << "Missed: " << File << endl;
+		  NotFound++;
+		  continue;
+	       }
+	       if (Chop != 0)
+		  File = OrigPath + ChopDirs(File,Chop);
+	    }
+
+	    // Get the size
+	    struct stat Buf;
+	    if (stat((CDROM + Prefix + File).c_str(),&Buf) != 0 ||
+		Buf.st_size == 0)
+	    {
+	       bool Mangled = false;
+	       // Attempt to fix busted symlink support for one instance
+	       string OrigFile = File;
+	       string::size_type Start = File.find("binary-");
+	       string::size_type End = File.find("/",Start+3);
+	       if (Start != string::npos && End != string::npos)
+	       {
+		  File.replace(Start,End-Start,"binary-all");
+		  Mangled = true;
+	       }
+
+	       if (Mangled == false ||
+		   stat((CDROM + Prefix + File).c_str(),&Buf) != 0)
+	       {
+		  if (Debug == true)
+		     clog << "Missed(2): " << OrigFile << endl;
+		  NotFound++;
+		  continue;
+	       }
+	    }
+
+	    // Size match
+	    if ((unsigned long long)Buf.st_size != Size)
+	    {
+	       if (Debug == true)
+		  clog << "Wrong Size: " << File << endl;
+	       WrongSize++;
+	       continue;
+	    }
+	 }
+
+	 Packages++;
+	 Hits++;
+
+	 if (RewriteEntry(Target, File) == false)
+	    return false;
+      }
+
+      if (Debug == true)
+	 cout << " Processed by using Prefix '" << Prefix << "' and chop " << Chop << endl;
+
+      if (_config->FindB("APT::CDROM::NoAct",false) == false)
+      {
+	 // Move out of the partial directory
+	 Target.Close();
+	 string FinalF = _config->FindDir("Dir::State::lists");
+	 FinalF += URItoFileName(S);
+	 if (rename(TargetF.c_str(),FinalF.c_str()) != 0)
+	    return _error->Errno("rename","Failed to rename");
+	 ChangeOwnerAndPermissionOfFile("CopyPackages", FinalF.c_str(), "root", ROOT_GROUP, 0644);
+      }
+
+      /* Mangle the source to be in the proper notation with
+	 prefix dist [component] */
+      *I = string(*I,Prefix.length());
+      ConvertToSourceList(CDROM,*I);
+      *I = Prefix + ' ' + *I;
+
+      CurrentSize += FileSize;
+   }
+   if(Progress)
+      Progress->Done();
+
+   // Some stats
+   if(log) {
+      stringstream msg;
+      if(NotFound == 0 && WrongSize == 0)
+	 ioprintf(msg, _("Wrote %i records.\n"), Packages);
+      else if (NotFound != 0 && WrongSize == 0)
+	 ioprintf(msg, _("Wrote %i records with %i missing files.\n"),
+		  Packages, NotFound);
+      else if (NotFound == 0 && WrongSize != 0)
+	 ioprintf(msg, _("Wrote %i records with %i mismatched files\n"),
+		  Packages, WrongSize);
+      if (NotFound != 0 && WrongSize != 0)
+	 ioprintf(msg, _("Wrote %i records with %i missing files and %i mismatched files\n"), Packages, NotFound, WrongSize);
+   }
+
+   if (Packages == 0)
+      _error->Warning("No valid records were found.");
+
+   if (NotFound + WrongSize > 10)
+      _error->Warning("A lot of entries were discarded, something may be wrong.\n");
+
+   return true;
+}
+									/*}}}*/
+// IndexCopy::ChopDirs - Chop off the leading directory components	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string IndexCopy::ChopDirs(string Path,unsigned int Depth)
+{
+   string::size_type I = 0;
+   do
+   {
+      I = Path.find('/',I+1);
+      Depth--;
+   }
+   while (I != string::npos && Depth != 0);
+
+   if (I == string::npos)
+      return string();
+
+   return string(Path,I+1);
+}
+									/*}}}*/
+// IndexCopy::ReconstructPrefix - Fix strange prefixing			/*{{{*/
+// ---------------------------------------------------------------------
+/* This prepends dir components from the path to the package files to
+   the path to the deb until it is found */
+bool IndexCopy::ReconstructPrefix(string &Prefix,string OrigPath,string CD,
+				  string File)
+{
+   bool Debug = _config->FindB("Debug::aptcdrom",false);
+   unsigned int Depth = 1;
+   string MyPrefix = Prefix;
+   while (1)
+   {
+      struct stat Buf;
+      if (stat((CD + MyPrefix + File).c_str(),&Buf) != 0)
+      {
+	 if (Debug == true)
+	    cout << "Failed, " << CD + MyPrefix + File << endl;
+	 if (GrabFirst(OrigPath,MyPrefix,Depth++) == true)
+	    continue;
+	 
+	 return false;
+      }
+      else
+      {
+	 Prefix = MyPrefix;
+	 return true;
+      }      
+   }
+   return false;
+}
+									/*}}}*/
+// IndexCopy::ReconstructChop - Fixes bad source paths			/*{{{*/
+// ---------------------------------------------------------------------
+/* This removes path components from the filename and prepends the location
+   of the package files until a file is found */
+bool IndexCopy::ReconstructChop(unsigned long &Chop,string Dir,string File)
+{
+   // Attempt to reconstruct the filename
+   unsigned long Depth = 0;
+   while (1)
+   {
+      struct stat Buf;
+      if (stat((Dir + File).c_str(),&Buf) != 0)
+      {
+	 File = ChopDirs(File,1);
+	 Depth++;
+	 if (File.empty() == false)
+	    continue;
+	 return false;
+      }
+      else
+      {
+	 Chop = Depth;
+	 return true;
+      }
+   }
+   return false;
+}
+									/*}}}*/
+// IndexCopy::ConvertToSourceList - Convert a Path to a sourcelist 	/*{{{*/
+// ---------------------------------------------------------------------
+/* We look for things in dists/ notation and convert them to 
+   <dist> <component> form otherwise it is left alone. This also strips
+   the CD path. 
+ 
+   This implements a regex sort of like: 
+    (.*)/dists/([^/]*)/(.*)/binary-* 
+     ^          ^      ^- Component
+     |          |-------- Distribution
+     |------------------- Path
+   
+   It was deciced to use only a single word for dist (rather than say
+   unstable/non-us) to increase the chance that each CD gets a single
+   line in sources.list.
+ */
+void IndexCopy::ConvertToSourceList(string CD,string &Path)
+{
+   // Strip the cdrom base path
+   Path = string(Path,CD.length());
+   if (Path.empty() == true)
+      Path = "/";
+   
+   // Too short to be a dists/ type
+   if (Path.length() < strlen("dists/"))
+      return;
+   
+   // Not a dists type.
+   if (stringcmp(Path.c_str(),Path.c_str()+strlen("dists/"),"dists/") != 0)
+      return;
+      
+   // Isolate the dist
+   string::size_type Slash = strlen("dists/");
+   string::size_type Slash2 = Path.find('/',Slash + 1);
+   if (Slash2 == string::npos || Slash2 + 2 >= Path.length())
+      return;
+   string Dist = string(Path,Slash,Slash2 - Slash);
+   
+   // Isolate the component
+   Slash = Slash2;
+   for (unsigned I = 0; I != 10; I++)
+   {
+      Slash = Path.find('/',Slash+1);
+      if (Slash == string::npos || Slash + 2 >= Path.length())
+	 return;
+      string Comp = string(Path,Slash2+1,Slash - Slash2-1);
+	 
+      // Verify the trailing binary- bit
+      string::size_type BinSlash = Path.find('/',Slash + 1);
+      if (Slash == string::npos)
+	 return;
+      string Binary = string(Path,Slash+1,BinSlash - Slash-1);
+      
+      if (strncmp(Binary.c_str(), "binary-", strlen("binary-")) == 0)
+      {
+	 Binary.erase(0, strlen("binary-"));
+	 if (APT::Configuration::checkArchitecture(Binary) == false)
+	    continue;
+      }
+      else if (Binary != "source")
+	 continue;
+
+      Path = Dist + ' ' + Comp;
+      return;
+   }   
+}
+									/*}}}*/
+// IndexCopy::GrabFirst - Return the first Depth path components	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool IndexCopy::GrabFirst(string Path,string &To,unsigned int Depth)
+{
+   string::size_type I = 0;
+   do
+   {
+      I = Path.find('/',I+1);
+      Depth--;
+   }
+   while (I != string::npos && Depth != 0);
+   
+   if (I == string::npos)
+      return false;
+
+   To = string(Path,0,I+1);
+   return true;
+}
+									/*}}}*/
+// PackageCopy::GetFile - Get the file information from the section	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool PackageCopy::GetFile(string &File,unsigned long long &Size)
+{
+   File = Section->Find(pkgTagSection::Key::Filename).to_string();
+   Size = Section->FindULL(pkgTagSection::Key::Size);
+   if (File.empty() || Size == 0)
+      return _error->Error("Cannot find filename or size tag");
+   return true;
+}
+									/*}}}*/
+// PackageCopy::RewriteEntry - Rewrite the entry with a new filename	/*{{{*/
+bool PackageCopy::RewriteEntry(FileFd &Target,string const &File)
+{
+   std::vector<pkgTagSection::Tag> Changes;
+   Changes.push_back(pkgTagSection::Tag::Rewrite("Filename", File));
+
+   if (Section->Write(Target, TFRewritePackageOrder, Changes) == false)
+      return false;
+   return Target.Write("\n", 1);
+}
+									/*}}}*/
+// SourceCopy::GetFile - Get the file information from the section	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool SourceCopy::GetFile(string &File,unsigned long long &Size)
+{
+   std::string Files;
+   for (auto hashinfo : HashString::SupportedHashesInfo())
+   {
+      Files = Section->Find(hashinfo.chksumskey).to_string();
+      if (not Files.empty())
+	 break;
+   }
+   if (Files.empty())
+      return false;
+
+   // Read the first file triplet
+   const char *C = Files.c_str();
+   string sSize;
+   string MD5Hash;
+   
+   // Parse each of the elements
+   if (ParseQuoteWord(C,MD5Hash) == false ||
+       ParseQuoteWord(C,sSize) == false ||
+       ParseQuoteWord(C,File) == false)
+      return _error->Error("Error parsing file record");
+   
+   // Parse the size and append the directory
+   Size = strtoull(sSize.c_str(), NULL, 10);
+   auto const Base = Section->Find(pkgTagSection::Key::Directory);
+   File = flCombine(Base.to_string(), File);
+   return true;
+}
+									/*}}}*/
+// SourceCopy::RewriteEntry - Rewrite the entry with a new filename	/*{{{*/
+bool SourceCopy::RewriteEntry(FileFd &Target, std::string const &File)
+{
+   string const Dir(File,0,File.rfind('/'));
+   std::vector<pkgTagSection::Tag> Changes;
+   Changes.push_back(pkgTagSection::Tag::Rewrite("Directory", Dir));
+
+   if (Section->Write(Target, TFRewriteSourceOrder, Changes) == false)
+      return false;
+   return Target.Write("\n", 1);
+}
+									/*}}}*/
+// SigVerify::Verify - Verify a files md5sum against its metaindex	/*{{{*/
+bool SigVerify::Verify(string prefix, string file, metaIndex *MetaIndex)
+{
+   const metaIndex::checkSum *Record = MetaIndex->Lookup(file);
+   bool const Debug = _config->FindB("Debug::aptcdrom",false);
+
+   // we skip non-existing files in the verifcation of the Release file
+   // as non-existing files do not harm, but a warning scares people and
+   // makes it hard to strip unneeded files from an ISO like uncompressed
+   // indexes as it is done on the mirrors (see also LP: #255545 )
+   if(!RealFileExists(prefix+file))
+   {
+      if (Debug == true)
+	 cout << "Skipping nonexistent in " << prefix << " file " << file << std::endl;
+      return true;
+   }
+
+   if (!Record)
+   {
+      _error->Warning(_("Can't find authentication record for: %s"), file.c_str());
+      return false;
+   }
+
+   if (!Record->Hashes.VerifyFile(prefix+file))
+   {
+      _error->Warning(_("Hash mismatch for: %s"),file.c_str());
+      return false;
+   }
+
+   if(Debug == true)
+   {
+      cout << "File: " << prefix+file << endl
+	 << "Expected Hash " << endl;
+      for (HashStringList::const_iterator hs = Record->Hashes.begin(); hs != Record->Hashes.end(); ++hs)
+	 std::cout <<  "\t- " << hs->toStr() << std::endl;
+   }
+
+   return true;
+}
+									/*}}}*/
+bool SigVerify::CopyMetaIndex(string CDROM, string CDName,		/*{{{*/
+			      string prefix, string file)
+{
+      char S[400];
+      snprintf(S,sizeof(S),"cdrom:[%s]/%s%s",CDName.c_str(),
+	       (prefix).c_str() + CDROM.length(),file.c_str());
+      string TargetF = _config->FindDir("Dir::State::lists");
+      TargetF += URItoFileName(S);
+
+      FileFd Target;
+      FileFd Rel;
+      Target.Open(TargetF,FileFd::WriteAtomic);
+      Rel.Open(prefix + file,FileFd::ReadOnly);
+      if (CopyFile(Rel,Target) == false || Target.Close() == false)
+	 return _error->Error("Copying of '%s' for '%s' from '%s' failed", file.c_str(), CDName.c_str(), prefix.c_str());
+      ChangeOwnerAndPermissionOfFile("CopyPackages", TargetF.c_str(), "root", ROOT_GROUP, 0644);
+
+      return true;
+}
+									/*}}}*/
+bool SigVerify::CopyAndVerify(string CDROM,string Name,vector<string> &SigList,	/*{{{*/
+			      vector<string> /*PkgList*/,vector<string> /*SrcList*/)
+{
+   if (SigList.empty() == true)
+      return true;
+
+   bool Debug = _config->FindB("Debug::aptcdrom",false);
+
+   // Read all Release files
+   for (vector<string>::iterator I = SigList.begin(); I != SigList.end(); ++I)
+   {
+      if(Debug)
+	 cout << "Signature verify for: " << *I << endl;
+
+      metaIndex *MetaIndex = new debReleaseIndex("","", {});
+      string prefix = *I; 
+
+      string const releasegpg = *I+"Release.gpg";
+      string const release = *I+"Release";
+      string const inrelease = *I+"InRelease";
+      bool useInRelease = true;
+
+      // a Release.gpg without a Release should never happen
+      if (RealFileExists(inrelease) == true)
+	 ;
+      else if(RealFileExists(release) == false || RealFileExists(releasegpg) == false)
+      {
+	 delete MetaIndex;
+	 continue;
+      }
+      else
+	 useInRelease = false;
+
+      pid_t pid = ExecFork();
+      if(pid < 0) {
+	 _error->Error("Fork failed");
+	 return false;
+      }
+      if(pid == 0)
+      {
+	 if (useInRelease == true)
+	    ExecGPGV(inrelease, inrelease);
+	 else
+	    ExecGPGV(release, releasegpg);
+      }
+
+      if(!ExecWait(pid, "gpgv")) {
+	 _error->Warning("Signature verification failed for: %s",
+			 (useInRelease ? inrelease.c_str() : releasegpg.c_str()));
+	 // something went wrong, don't copy the Release.gpg
+	 // FIXME: delete any existing gpg file?
+	 delete MetaIndex;
+	 continue;
+      }
+
+      // Open the Release file and add it to the MetaIndex
+      std::string ErrorText;
+      if(MetaIndex->Load(release, &ErrorText) == false)
+      {
+	 _error->Error("%s", ErrorText.c_str());
+	 return false;
+      }
+
+      // go over the Indexfiles and see if they verify
+      // if so, remove them from our copy of the lists
+      vector<string> keys = MetaIndex->MetaKeys();
+      for (vector<string>::iterator I = keys.begin(); I != keys.end(); ++I)
+      { 
+	 if(!Verify(prefix,*I, MetaIndex)) {
+	    // something went wrong, don't copy the Release.gpg
+	    // FIXME: delete any existing gpg file?
+	    _error->Discard();
+	    continue;	 
+	 }
+      }
+
+      // we need a fresh one for the Release.gpg
+      delete MetaIndex;
+   
+      // everything was fine, copy the Release and Release.gpg file
+      if (useInRelease == true)
+	 CopyMetaIndex(CDROM, Name, prefix, "InRelease");
+      else
+      {
+	 CopyMetaIndex(CDROM, Name, prefix, "Release");
+	 CopyMetaIndex(CDROM, Name, prefix, "Release.gpg");
+      }
+   }   
+
+   return true;
+}
+									/*}}}*/
+bool TranslationsCopy::CopyTranslations(string CDROM,string Name,	/*{{{*/
+				vector<string> &List, pkgCdromStatus *log)
+{
+   OpProgress *Progress = NULL;
+   if (List.empty() == true)
+      return true;
+   
+   if(log) 
+      Progress = log->GetOpProgress();
+   
+   bool Debug = _config->FindB("Debug::aptcdrom",false);
+   
+   // Prepare the progress indicator
+   off_t TotalSize = 0;
+   std::vector<APT::Configuration::Compressor> const compressor = APT::Configuration::getCompressors();
+   for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      struct stat Buf;
+      bool found = false;
+      std::string file = *I;
+      for (std::vector<APT::Configuration::Compressor>::const_iterator c = compressor.begin();
+	   c != compressor.end(); ++c)
+      {
+	 if (stat((file + c->Extension).c_str(), &Buf) != 0)
+	    continue;
+	 found = true;
+	 break;
+      }
+
+      if (found == false)
+	 return _error->Errno("stat", "Stat failed for %s", file.c_str());
+      TotalSize += Buf.st_size;
+   }
+
+   off_t CurrentSize = 0;
+   unsigned int NotFound = 0;
+   unsigned int WrongSize = 0;
+   unsigned int Packages = 0;
+   for (vector<string>::iterator I = List.begin(); I != List.end(); ++I)
+   {
+      // Open the package file
+      FileFd Pkg(*I, FileFd::ReadOnly, FileFd::Auto);
+      off_t const FileSize = Pkg.Size();
+
+      pkgTagFile Parser(&Pkg);
+      if (Pkg.IsOpen() == false || Pkg.Failed())
+	 return false;
+
+      // Open the output file
+      char S[400];
+      snprintf(S,sizeof(S),"cdrom:[%s]/%s",Name.c_str(),
+	       (*I).c_str() + CDROM.length());
+      string TargetF = _config->FindDir("Dir::State::lists") + "partial/";
+      TargetF += URItoFileName(S);
+      FileFd Target;
+      if (_config->FindB("APT::CDROM::NoAct",false) == true)
+      {
+	 TargetF = "/dev/null";
+	 Target.Open(TargetF,FileFd::WriteExists);
+      } else {
+	 Target.Open(TargetF,FileFd::WriteAtomic);
+      }
+      if (Pkg.IsOpen() == false || Pkg.Failed())
+	 return false;
+
+      // Setup the progress meter
+      if(Progress)
+	 Progress->OverallProgress(CurrentSize,TotalSize,FileSize,
+				   string("Reading Translation Indexes"));
+
+      // Parse
+      if(Progress)
+	 Progress->SubProgress(Pkg.Size());
+      pkgTagSection Section;
+      this->Section = &Section;
+      string Prefix;
+      unsigned long Hits = 0;
+      while (Parser.Step(Section) == true)
+      {
+	 if(Progress)
+	    Progress->Progress(Parser.Offset());
+
+	 if (Section.Write(Target) == false || Target.Write("\n", 1) == false)
+	    return false;
+
+	 Packages++;
+	 Hits++;
+      }
+
+      if (Debug == true)
+	 cout << " Processed by using Prefix '" << Prefix << "' and chop " << endl;
+
+      if (_config->FindB("APT::CDROM::NoAct",false) == false)
+      {
+	 // Move out of the partial directory
+	 Target.Close();
+	 string FinalF = _config->FindDir("Dir::State::lists");
+	 FinalF += URItoFileName(S);
+	 if (rename(TargetF.c_str(),FinalF.c_str()) != 0)
+	    return _error->Errno("rename","Failed to rename");
+	 ChangeOwnerAndPermissionOfFile("CopyTranslations", FinalF.c_str(), "root", ROOT_GROUP, 0644);
+      }
+
+      CurrentSize += FileSize;
+   }
+   if(Progress)
+      Progress->Done();
+
+   // Some stats
+   if(log) {
+      stringstream msg;
+      if(NotFound == 0 && WrongSize == 0)
+	 ioprintf(msg, _("Wrote %i records.\n"), Packages);
+      else if (NotFound != 0 && WrongSize == 0)
+	 ioprintf(msg, _("Wrote %i records with %i missing files.\n"),
+		  Packages, NotFound);
+      else if (NotFound == 0 && WrongSize != 0)
+	 ioprintf(msg, _("Wrote %i records with %i mismatched files\n"),
+		  Packages, WrongSize);
+      if (NotFound != 0 && WrongSize != 0)
+	 ioprintf(msg, _("Wrote %i records with %i missing files and %i mismatched files\n"), Packages, NotFound, WrongSize);
+   }
+
+   if (Packages == 0)
+      _error->Warning("No valid records were found.");
+
+   if (NotFound + WrongSize > 10)
+      _error->Warning("A lot of entries were discarded, something may be wrong.\n");
+
+   return true;
+}
+									/*}}}*/
+
+IndexCopy::IndexCopy() : d(nullptr), Section(nullptr) {}
+IndexCopy::~IndexCopy() {}
+
+PackageCopy::PackageCopy() : IndexCopy(), d(NULL) {}
+PackageCopy::~PackageCopy() {}
+SourceCopy::SourceCopy() : IndexCopy(), d(NULL) {}
+SourceCopy::~SourceCopy() {}
+TranslationsCopy::TranslationsCopy() : d(nullptr), Section(nullptr) {}
+TranslationsCopy::~TranslationsCopy() {}
+SigVerify::SigVerify() : d(NULL) {}
+SigVerify::~SigVerify() {}
diff --git a/apt-pkg/indexcopy.h b/apt-pkg/indexcopy.h
new file mode 100644
index 0000000..41be154
--- /dev/null
+++ b/apt-pkg/indexcopy.h
@@ -0,0 +1,116 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Index Copying - Aid for copying and verifying the index files
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef INDEXCOPY_H
+#define INDEXCOPY_H
+
+#include <vector>
+#ifndef APT_11_CLEAN_HEADERS
+#include <string>
+#include <stdio.h>
+#endif
+
+#include <apt-pkg/macros.h>
+
+
+class pkgTagSection;
+class pkgCdromStatus;
+class FileFd;
+class metaIndex;
+
+class APT_PUBLIC IndexCopy								/*{{{*/
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   protected:
+   
+   pkgTagSection *Section;
+   
+   std::string ChopDirs(std::string Path,unsigned int Depth);
+   bool ReconstructPrefix(std::string &Prefix,std::string OrigPath,std::string CD,
+			  std::string File);
+   bool ReconstructChop(unsigned long &Chop,std::string Dir,std::string File);
+   void ConvertToSourceList(std::string CD,std::string &Path);
+   bool GrabFirst(std::string Path,std::string &To,unsigned int Depth);
+   virtual bool GetFile(std::string &Filename,unsigned long long &Size) = 0;
+   virtual bool RewriteEntry(FileFd &Target, std::string const &File) = 0;
+   virtual const char *GetFileName() = 0;
+   virtual const char *Type() = 0;
+   
+   public:
+
+   bool CopyPackages(std::string CDROM,std::string Name,std::vector<std::string> &List,
+		     pkgCdromStatus *log);
+   IndexCopy();
+   virtual ~IndexCopy();
+};
+									/*}}}*/
+class APT_PUBLIC PackageCopy : public IndexCopy					/*{{{*/
+{
+   void * const d;
+   protected:
+
+   virtual bool GetFile(std::string &Filename,unsigned long long &Size) APT_OVERRIDE;
+   virtual bool RewriteEntry(FileFd &Target, std::string const &File) APT_OVERRIDE;
+   virtual const char *GetFileName() APT_OVERRIDE {return "Packages";};
+   virtual const char *Type() APT_OVERRIDE {return "Package";};
+
+   public:
+   PackageCopy();
+   virtual ~PackageCopy();
+};
+									/*}}}*/
+class APT_PUBLIC SourceCopy : public IndexCopy					/*{{{*/
+{
+   void * const d;
+   protected:
+   
+   virtual bool GetFile(std::string &Filename,unsigned long long &Size) APT_OVERRIDE;
+   virtual bool RewriteEntry(FileFd &Target, std::string const &File) APT_OVERRIDE;
+   virtual const char *GetFileName() APT_OVERRIDE {return "Sources";};
+   virtual const char *Type() APT_OVERRIDE {return "Source";};
+
+   public:
+   SourceCopy();
+   virtual ~SourceCopy();
+};
+									/*}}}*/
+class APT_PUBLIC  TranslationsCopy							/*{{{*/
+{
+   void * const d;
+   protected:
+   pkgTagSection *Section;
+
+   public:
+   bool CopyTranslations(std::string CDROM,std::string Name,std::vector<std::string> &List,
+			 pkgCdromStatus *log);
+
+   TranslationsCopy();
+   virtual ~TranslationsCopy();
+};
+									/*}}}*/
+class APT_PUBLIC SigVerify								/*{{{*/
+{
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+
+   APT_HIDDEN bool Verify(std::string prefix,std::string file, metaIndex *records);
+   APT_HIDDEN bool CopyMetaIndex(std::string CDROM, std::string CDName,
+		      std::string prefix, std::string file);
+
+ public:
+   bool CopyAndVerify(std::string CDROM,std::string Name,std::vector<std::string> &SigList,
+		      std::vector<std::string> PkgList,std::vector<std::string> SrcList);
+
+   SigVerify();
+   virtual ~SigVerify();
+};
+									/*}}}*/
+
+#endif
diff --git a/apt-pkg/indexfile.cc b/apt-pkg/indexfile.cc
new file mode 100644
index 0000000..f13b529
--- /dev/null
+++ b/apt-pkg/indexfile.cc
@@ -0,0 +1,384 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Index File - Abstraction for an index of archive/source file.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/deblistparser.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/srcrecords.h>
+#include <apt-pkg/strutl.h>
+
+#include <apt-pkg/debindexfile.h>
+
+#include <sys/stat.h>
+
+#include <clocale>
+#include <cstring>
+#include <memory>
+#include <string>
+#include <vector>
+									/*}}}*/
+
+// Global list of Item supported
+static  pkgIndexFile::Type *ItmList[10];
+pkgIndexFile::Type **pkgIndexFile::Type::GlobalList = ItmList;
+unsigned long pkgIndexFile::Type::GlobalListLen = 0;
+
+// Type::Type - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgIndexFile::Type::Type()
+{
+   ItmList[GlobalListLen] = this;
+   GlobalListLen++;
+   Label = NULL;
+}
+									/*}}}*/
+// Type::GetType - Locate the type by name				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgIndexFile::Type *pkgIndexFile::Type::GetType(const char *Type)
+{
+   for (unsigned I = 0; I != GlobalListLen; I++)
+      if (strcmp(GlobalList[I]->Label,Type) == 0)
+	 return GlobalList[I];
+   return 0;
+}
+									/*}}}*/
+pkgIndexFile::pkgIndexFile(bool const Trusted) :			/*{{{*/
+   d(NULL), Trusted(Trusted)
+{
+}
+									/*}}}*/
+// IndexFile::ArchiveInfo - Stub					/*{{{*/
+std::string pkgIndexFile::ArchiveInfo(pkgCache::VerIterator const &) const
+{
+   return std::string();
+}
+									/*}}}*/
+// IndexFile::FindInCache - Stub					/*{{{*/
+pkgCache::PkgFileIterator pkgIndexFile::FindInCache(pkgCache &Cache) const
+{
+   return pkgCache::PkgFileIterator(Cache);
+}
+									/*}}}*/
+// IndexFile::SourceIndex - Stub					/*{{{*/
+std::string pkgIndexFile::SourceInfo(pkgSrcRecords::Parser const &/*Record*/,
+				pkgSrcRecords::File const &/*File*/) const
+{
+   return std::string();
+}
+									/*}}}*/
+
+// IndexTarget - Constructor						/*{{{*/
+IndexTarget::IndexTarget(std::string const &MetaKey, std::string const &ShortDesc,
+      std::string const &LongDesc, std::string const &URI, bool const IsOptional,
+      bool const KeepCompressed, std::map<std::string, std::string> const &Options) :
+   URI(URI), Description(LongDesc), ShortDesc(ShortDesc), MetaKey(MetaKey),
+   IsOptional(IsOptional), KeepCompressed(KeepCompressed), Options(Options)
+{
+}
+									/*}}}*/
+std::string IndexTarget::Option(OptionKeys const EnumKey) const		/*{{{*/
+{
+   std::string Key;
+   switch (EnumKey)
+   {
+#define APT_CASE(X) case X: Key = #X; break
+      APT_CASE(SITE);
+      APT_CASE(RELEASE);
+      APT_CASE(COMPONENT);
+      APT_CASE(LANGUAGE);
+      APT_CASE(ARCHITECTURE);
+      APT_CASE(BASE_URI);
+      APT_CASE(REPO_URI);
+      APT_CASE(IDENTIFIER);
+      APT_CASE(TARGET_OF);
+      APT_CASE(CREATED_BY);
+      APT_CASE(FALLBACK_OF);
+      APT_CASE(PDIFFS);
+      APT_CASE(DEFAULTENABLED);
+      APT_CASE(COMPRESSIONTYPES);
+      APT_CASE(SOURCESENTRY);
+      APT_CASE(BY_HASH);
+      APT_CASE(KEEPCOMPRESSEDAS);
+      APT_CASE(ALLOW_INSECURE);
+      APT_CASE(ALLOW_WEAK);
+      APT_CASE(ALLOW_DOWNGRADE_TO_INSECURE);
+      APT_CASE(INRELEASE_PATH);
+#undef APT_CASE
+      case FILENAME:
+      {
+	 auto const M = Options.find("FILENAME");
+	 if (M == Options.end())
+	    return _config->FindDir("Dir::State::lists") + URItoFileName(URI);
+	 return M->second;
+      }
+      case EXISTING_FILENAME:
+	 std::string const filename = Option(FILENAME);
+	 std::vector<std::string> const types = VectorizeString(Option(COMPRESSIONTYPES), ' ');
+	 for (std::vector<std::string>::const_iterator t = types.begin(); t != types.end(); ++t)
+	 {
+	    if (t->empty())
+	       continue;
+	    std::string const file = (*t == "uncompressed") ? filename : (filename + "." + *t);
+	    if (FileExists(file))
+	       return file;
+	 }
+	 return "";
+   }
+   std::map<std::string,std::string>::const_iterator const M = Options.find(Key);
+   if (M == Options.end())
+      return "";
+   return M->second;
+}
+									/*}}}*/
+bool IndexTarget::OptionBool(OptionKeys const EnumKey) const		/*{{{*/
+{
+   return StringToBool(Option(EnumKey), false);
+}
+									/*}}}*/
+std::string IndexTarget::Format(std::string format) const		/*{{{*/
+{
+   for (std::map<std::string, std::string>::const_iterator O = Options.begin(); O != Options.end(); ++O)
+   {
+      format = SubstVar(format, std::string("$(") + O->first + ")", O->second);
+   }
+   format = SubstVar(format, "$(METAKEY)", MetaKey);
+   format = SubstVar(format, "$(SHORTDESC)", ShortDesc);
+   format = SubstVar(format, "$(DESCRIPTION)", Description);
+   format = SubstVar(format, "$(URI)", URI);
+   format = SubstVar(format, "$(FILENAME)", Option(IndexTarget::FILENAME));
+   return format;
+}
+									/*}}}*/
+
+pkgDebianIndexTargetFile::pkgDebianIndexTargetFile(IndexTarget const &Target, bool const Trusted) :/*{{{*/
+   pkgDebianIndexFile(Trusted), d(NULL), Target(Target)
+{
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::ArchiveURI(std::string const &File) const/*{{{*/
+{
+   return Target.Option(IndexTarget::REPO_URI) + pkgAcquire::URIEncode(File);
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::Describe(bool const Short) const	/*{{{*/
+{
+   if (Short)
+      return Target.Description;
+   return Target.Description + " (" + IndexFileName() + ")";
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::IndexFileName() const			/*{{{*/
+{
+   std::string const s = Target.Option(IndexTarget::FILENAME);
+   if (FileExists(s))
+      return s;
+
+   std::vector<std::string> const types = VectorizeString(Target.Option(IndexTarget::COMPRESSIONTYPES), ' ');
+   for (std::vector<std::string>::const_iterator t = types.begin(); t != types.end(); ++t)
+   {
+      std::string p = s + '.' + *t;
+      if (FileExists(p))
+         return p;
+   }
+   return s;
+}
+									/*}}}*/
+unsigned long pkgDebianIndexTargetFile::Size() const				/*{{{*/
+{
+   unsigned long size = 0;
+
+   /* we need to ignore errors here; if the lists are absent, just return 0 */
+   _error->PushToStack();
+
+   FileFd f(IndexFileName(), FileFd::ReadOnly, FileFd::Extension);
+   if (!f.Failed())
+      size = f.Size();
+
+   if (_error->PendingError() == true)
+       size = 0;
+   _error->RevertToStack();
+
+   return size;
+}
+									/*}}}*/
+bool pkgDebianIndexTargetFile::Exists() const					/*{{{*/
+{
+   return FileExists(IndexFileName());
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::GetArchitecture() const			/*{{{*/
+{
+   return Target.Option(IndexTarget::ARCHITECTURE);
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::GetComponent() const			/*{{{*/
+{
+   return Target.Option(IndexTarget::COMPONENT);
+}
+									/*}}}*/
+bool pkgDebianIndexTargetFile::OpenListFile(FileFd &Pkg, std::string const &FileName)/*{{{*/
+{
+   if (Pkg.Open(FileName, FileFd::ReadOnly, FileFd::Extension) == false)
+      return _error->Error("Problem opening %s",FileName.c_str());
+   return true;
+}
+									/*}}}*/
+std::string pkgDebianIndexTargetFile::GetProgressDescription() const
+{
+   return Target.Description;
+}
+IndexTarget pkgDebianIndexTargetFile::GetIndexTarget() const
+{
+   return Target;
+}
+
+pkgDebianIndexRealFile::pkgDebianIndexRealFile(std::string const &pFile, bool const Trusted) :/*{{{*/
+   pkgDebianIndexFile(Trusted), d(NULL)
+{
+   if (pFile.empty())
+      ;
+   else if (pFile == "/nonexistent/stdin")
+      File = pFile;
+   else
+      File = flAbsPath(pFile);
+}
+									/*}}}*/
+// IndexRealFile::Size - Return the size of the index			/*{{{*/
+unsigned long pkgDebianIndexRealFile::Size() const
+{
+   struct stat S;
+   if (stat(File.c_str(),&S) != 0)
+      return 0;
+   return S.st_size;
+}
+									/*}}}*/
+bool pkgDebianIndexRealFile::Exists() const					/*{{{*/
+{
+   return FileExists(File);
+}
+									/*}}}*/
+std::string pkgDebianIndexRealFile::Describe(bool const /*Short*/) const/*{{{*/
+{
+   return File;
+}
+									/*}}}*/
+std::string pkgDebianIndexRealFile::ArchiveURI(std::string const &/*File*/) const/*{{{*/
+{
+   return "file:" + pkgAcquire::URIEncode(File);
+}
+									/*}}}*/
+std::string pkgDebianIndexRealFile::IndexFileName() const			/*{{{*/
+{
+   return File;
+}
+									/*}}}*/
+std::string pkgDebianIndexRealFile::GetProgressDescription() const
+{
+   return File;
+}
+bool pkgDebianIndexRealFile::OpenListFile(FileFd &Pkg, std::string const &FileName)/*{{{*/
+{
+   if (Pkg.Open(FileName, FileFd::ReadOnly, FileFd::Extension) == false)
+      return _error->Error("Problem opening %s",FileName.c_str());
+   return true;
+}
+									/*}}}*/
+
+pkgDebianIndexFile::pkgDebianIndexFile(bool const Trusted) : pkgIndexFile(Trusted)
+{
+}
+pkgDebianIndexFile::~pkgDebianIndexFile()
+{
+}
+pkgCacheListParser * pkgDebianIndexFile::CreateListParser(FileFd &Pkg)
+{
+   if (Pkg.IsOpen() == false)
+      return nullptr;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(new debListParser(&Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   return newError ? nullptr : Parser.release();
+}
+bool pkgDebianIndexFile::Merge(pkgCacheGenerator &Gen,OpProgress * const Prog)
+{
+   std::string const PackageFile = IndexFileName();
+   FileFd Pkg;
+   if (OpenListFile(Pkg, PackageFile) == false)
+      return false;
+   _error->PushToStack();
+   std::unique_ptr<pkgCacheListParser> Parser(CreateListParser(Pkg));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   if (newError == false && Parser == nullptr)
+      return true;
+   if (Parser == NULL)
+      return false;
+
+   if (Prog != NULL)
+      Prog->SubProgress(0, GetProgressDescription());
+
+   if (Gen.SelectFile(PackageFile, *this, GetArchitecture(), GetComponent(), GetIndexFlags()) == false)
+      return _error->Error("Problem with SelectFile %s",PackageFile.c_str());
+
+   // Store the IMS information
+   pkgCache::PkgFileIterator File = Gen.GetCurFile();
+   pkgCacheGenerator::Dynamic<pkgCache::PkgFileIterator> DynFile(File);
+   File->Size = Pkg.FileSize();
+   File->mtime = Pkg.ModificationTime();
+
+   if (Gen.MergeList(*Parser) == false)
+      return _error->Error("Problem with MergeList %s",PackageFile.c_str());
+   return true;
+}
+pkgCache::PkgFileIterator pkgDebianIndexFile::FindInCache(pkgCache &Cache) const
+{
+   std::string const FileName = IndexFileName();
+   pkgCache::PkgFileIterator File = Cache.FileBegin();
+   for (; File.end() == false; ++File)
+   {
+       if (File.FileName() == NULL || FileName != File.FileName())
+	 continue;
+
+      struct stat St;
+      if (stat(File.FileName(),&St) != 0)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "DebianIndexFile::FindInCache - stat failed on " << File.FileName() << std::endl;
+	 return pkgCache::PkgFileIterator(Cache);
+      }
+      if ((map_filesize_t)St.st_size != File->Size || St.st_mtime != File->mtime)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "DebianIndexFile::FindInCache - size (" << St.st_size << " <> " << File->Size
+			<< ") or mtime (" << St.st_mtime << " <> " << File->mtime
+			<< ") doesn't match for " << File.FileName() << std::endl;
+	 return pkgCache::PkgFileIterator(Cache);
+      }
+      return File;
+   }
+
+   return File;
+}
+
+pkgIndexFile::~pkgIndexFile() {}
+pkgDebianIndexTargetFile::~pkgDebianIndexTargetFile() {}
+pkgDebianIndexRealFile::~pkgDebianIndexRealFile() {}
diff --git a/apt-pkg/indexfile.h b/apt-pkg/indexfile.h
new file mode 100644
index 0000000..d0b045a
--- /dev/null
+++ b/apt-pkg/indexfile.h
@@ -0,0 +1,214 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Index File - Abstraction for an index of archive/source file.
+   
+   There are 4 primary sorts of index files, all represented by this 
+   class:
+   
+   Binary index files 
+   Binary translation files 
+   Binary index files describing the local system
+   Source index files
+   
+   They are all bundled together here, and the interfaces for 
+   sources.list, acquire, cache gen and record parsing all use this class
+   to access the underlying representation.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_INDEXFILE_H
+#define PKGLIB_INDEXFILE_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+#include <apt-pkg/srcrecords.h>
+
+#include <map>
+#include <string>
+
+
+class pkgCacheGenerator;
+class pkgCacheListParser;
+class OpProgress;
+
+class APT_PUBLIC IndexTarget							/*{{{*/
+/** \brief Information about an index file. */
+{
+   public:
+   /** \brief A URI from which the index file can be downloaded. */
+   std::string URI;
+
+   /** \brief A description of the index file. */
+   std::string Description;
+
+   /** \brief A shorter description of the index file. */
+   std::string ShortDesc;
+
+   /** \brief The key by which this index file should be
+       looked up within the meta index file. */
+   std::string MetaKey;
+
+   /** \brief Is it okay if the file isn't found in the meta index */
+   bool IsOptional;
+
+   /** \brief If the file is downloaded compressed, do not unpack it */
+   bool KeepCompressed;
+
+   /** \brief options with which this target was created
+       Prefer the usage of #Option if at all possible.
+       Beware: Not all of these options are intended for public use */
+   std::map<std::string, std::string> Options;
+
+   IndexTarget(std::string const &MetaKey, std::string const &ShortDesc,
+	 std::string const &LongDesc, std::string const &URI, bool const IsOptional,
+	 bool const KeepCompressed, std::map<std::string, std::string> const &Options);
+
+   enum OptionKeys
+   {
+      SITE,
+      RELEASE,
+      COMPONENT,
+      LANGUAGE,
+      ARCHITECTURE,
+      BASE_URI,
+      REPO_URI,
+      CREATED_BY,
+      TARGET_OF,
+      FILENAME,
+      EXISTING_FILENAME,
+      PDIFFS,
+      COMPRESSIONTYPES,
+      DEFAULTENABLED,
+      SOURCESENTRY,
+      BY_HASH,
+      KEEPCOMPRESSEDAS,
+      FALLBACK_OF,
+      IDENTIFIER,
+      ALLOW_INSECURE,
+      ALLOW_WEAK,
+      ALLOW_DOWNGRADE_TO_INSECURE,
+      INRELEASE_PATH,
+   };
+   std::string Option(OptionKeys const Key) const;
+   bool OptionBool(OptionKeys const Key) const;
+   std::string Format(std::string format) const;
+};
+									/*}}}*/
+
+class APT_PUBLIC pkgIndexFile
+{
+   void * const d;
+   protected:
+   bool Trusted;
+
+   public:
+
+   class APT_PUBLIC Type
+   {
+      public:
+
+      // Global list of Items supported
+      static Type **GlobalList;
+      static unsigned long GlobalListLen;
+      static Type *GetType(const char * const Type) APT_PURE;
+
+      const char *Label;
+
+      virtual pkgRecords::Parser *CreatePkgParser(pkgCache::PkgFileIterator const &/*File*/) const {return 0;};
+      virtual pkgSrcRecords::Parser *CreateSrcPkgParser(std::string const &/*File*/) const {return 0;};
+      Type();
+      virtual ~Type() {};
+   };
+
+   virtual const Type *GetType() const = 0;
+   
+   // Return descriptive strings of various sorts
+   virtual std::string ArchiveInfo(pkgCache::VerIterator const &Ver) const;
+   virtual std::string SourceInfo(pkgSrcRecords::Parser const &Record,
+			     pkgSrcRecords::File const &File) const;
+   virtual std::string Describe(bool const Short = false) const = 0;
+
+   // Interface for acquire
+   virtual std::string ArchiveURI(std::string const &/*File*/) const {return std::string();};
+
+   // Interface for the record parsers
+   virtual pkgSrcRecords::Parser *CreateSrcParser() const {return 0;};
+   
+   // Interface for the Cache Generator
+   virtual bool Exists() const = 0;
+   virtual bool HasPackages() const = 0;
+   virtual unsigned long Size() const = 0;
+   virtual bool Merge(pkgCacheGenerator &/*Gen*/, OpProgress* const /*Prog*/) { return true; };
+   virtual pkgCache::PkgFileIterator FindInCache(pkgCache &Cache) const;
+
+   bool IsTrusted() const { return Trusted; };
+
+   explicit pkgIndexFile(bool const Trusted);
+   virtual ~pkgIndexFile();
+};
+
+class APT_PUBLIC pkgDebianIndexFile : public pkgIndexFile
+{
+protected:
+   virtual std::string IndexFileName() const = 0;
+   virtual std::string GetComponent() const = 0;
+   virtual std::string GetArchitecture() const = 0;
+   virtual std::string GetProgressDescription() const = 0;
+   virtual uint8_t GetIndexFlags() const = 0;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) = 0;
+   APT_HIDDEN virtual pkgCacheListParser * CreateListParser(FileFd &Pkg);
+
+public:
+   virtual bool Merge(pkgCacheGenerator &Gen, OpProgress* const Prog) APT_OVERRIDE;
+   virtual pkgCache::PkgFileIterator FindInCache(pkgCache &Cache) const APT_OVERRIDE;
+
+   explicit pkgDebianIndexFile(bool const Trusted);
+   virtual ~pkgDebianIndexFile();
+};
+
+class APT_PUBLIC pkgDebianIndexTargetFile : public pkgDebianIndexFile
+{
+   void * const d;
+protected:
+   IndexTarget const Target;
+
+   virtual std::string IndexFileName() const APT_OVERRIDE;
+   virtual std::string GetComponent() const APT_OVERRIDE;
+   virtual std::string GetArchitecture() const APT_OVERRIDE;
+   virtual std::string GetProgressDescription() const APT_OVERRIDE;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) APT_OVERRIDE;
+
+public:
+   virtual std::string ArchiveURI(std::string const &File) const APT_OVERRIDE;
+   virtual std::string Describe(bool const Short = false) const APT_OVERRIDE;
+   virtual bool Exists() const APT_OVERRIDE;
+   virtual unsigned long Size() const APT_OVERRIDE;
+   IndexTarget GetIndexTarget() const APT_HIDDEN;
+
+   pkgDebianIndexTargetFile(IndexTarget const &Target, bool const Trusted);
+   virtual ~pkgDebianIndexTargetFile();
+};
+
+class APT_PUBLIC pkgDebianIndexRealFile : public pkgDebianIndexFile
+{
+   void * const d;
+protected:
+   std::string File;
+
+   virtual std::string IndexFileName() const APT_OVERRIDE;
+   virtual std::string GetProgressDescription() const APT_OVERRIDE;
+   virtual bool OpenListFile(FileFd &Pkg, std::string const &FileName) APT_OVERRIDE;
+public:
+   virtual std::string Describe(bool const /*Short*/ = false) const APT_OVERRIDE;
+   virtual bool Exists() const APT_OVERRIDE;
+   virtual unsigned long Size() const APT_OVERRIDE;
+   virtual std::string ArchiveURI(std::string const &/*File*/) const APT_OVERRIDE;
+
+   pkgDebianIndexRealFile(std::string const &File, bool const Trusted);
+   virtual ~pkgDebianIndexRealFile();
+};
+
+#endif
diff --git a/apt-pkg/init.cc b/apt-pkg/init.cc
new file mode 100644
index 0000000..b9d9b15
--- /dev/null
+++ b/apt-pkg/init.cc
@@ -0,0 +1,289 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Init - Initialize the package library
+   
+   ##################################################################### */
+									/*}}}*/
+// Include files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/init.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/strutl.h>
+
+#include <cstdlib>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <unordered_map>
+#include <vector>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+#define Stringfy_(x) # x
+#define Stringfy(x)  Stringfy_(x)
+const char *pkgVersion = PACKAGE_VERSION;
+const char *pkgLibVersion = Stringfy(APT_PKG_MAJOR) "."
+                            Stringfy(APT_PKG_MINOR) "." 
+                            Stringfy(APT_PKG_RELEASE);
+namespace APT {
+   APT_HIDDEN extern std::unordered_map<std::string, std::vector<std::string>> ArchToTupleMap;
+}
+
+// Splits by whitespace. There may be continuous spans of whitespace - they
+// will be considered as one.
+static std::vector<std::string> split(std::string const & s)
+{
+   std::vector<std::string> vec;
+   std::istringstream iss(s);
+   iss.imbue(std::locale::classic());
+   for(std::string current_s; iss >> current_s; )
+      vec.push_back(current_s);
+   return vec;
+}
+
+
+// pkgInitArchTupleMap - Initialize the architecture tuple map				/*{{{*/
+// ---------------------------------------------------------------------
+/* This initializes */
+static bool pkgInitArchTupleMap()
+{
+   auto tuplepath = _config->FindFile("Dir::dpkg::tupletable", DPKG_DATADIR "/tupletable");
+   auto tripletpath = _config->FindFile("Dir::dpkg::triplettable", DPKG_DATADIR "/triplettable");
+   auto cpupath = _config->FindFile("Dir::dpkg::cputable", DPKG_DATADIR "/cputable");
+
+   // Load a list of CPUs
+   std::vector<std::string> cpus;
+   std::ifstream cputable(cpupath);
+   for (std::string cpuline; std::getline(cputable, cpuline); )
+   {
+      if (cpuline[0] == '#' || cpuline[0] == '\0')
+         continue;
+      auto cpurow = split(cpuline);
+      auto cpu = APT::String::Strip(cpurow.at(0));
+
+      cpus.push_back(cpu);
+   }
+   if (!cputable.eof())
+      return _error->Error("Error reading the CPU table");
+
+   // Load the architecture tuple
+   std::ifstream tupletable;
+   if (FileExists(tuplepath))
+      tupletable.open(tuplepath);
+   else if (FileExists(tripletpath))
+      tupletable.open(tripletpath);
+   else
+      return _error->Error("Cannot find dpkg tuplet or triplet table");
+
+   APT::ArchToTupleMap.clear();
+   for (std::string tupleline; std::getline(tupletable, tupleline); )
+   {
+      if (tupleline[0] == '#' || tupleline[0] == '\0')
+         continue;
+
+      std::vector<std::string> tuplerow = split(tupleline);
+
+      auto tuple = APT::String::Strip(tuplerow.at(0));
+      auto arch = APT::String::Strip(tuplerow.at(1));
+
+      if (tuple.find("<cpu>") == tuple.npos && arch.find("<cpu>") == arch.npos)
+      {
+         APT::ArchToTupleMap.insert({arch, VectorizeString(tuple, '-')});
+      }
+      else
+      {
+         for (auto && cpu : cpus)
+         {
+            auto mytuple = SubstVar(tuple, std::string("<cpu>"), cpu);
+            auto myarch = SubstVar(arch, std::string("<cpu>"), cpu);
+
+            APT::ArchToTupleMap.insert({myarch, VectorizeString(mytuple, '-')});
+         }
+      }
+   }
+   if (!tupletable.eof())
+      return _error->Error("Error reading the Tuple table");
+
+   return true;
+}
+									/*}}}*/
+
+    
+// pkgInitConfig - Initialize the configuration class			/*{{{*/
+// ---------------------------------------------------------------------
+/* Directories are specified in such a way that the FindDir function will
+   understand them. That is, if they don't start with a / then their parent
+   is prepended, this allows a fair degree of flexibility. */
+bool pkgInitConfig(Configuration &Cnf)
+{
+   // General APT things
+   Cnf.CndSet("APT::Architecture", COMMON_ARCH);
+   if (Cnf.Exists("APT::Build-Essential") == false)
+      Cnf.Set("APT::Build-Essential::", "build-essential");
+   Cnf.CndSet("APT::Install-Recommends", true);
+   Cnf.CndSet("APT::Install-Suggests", false);
+   Cnf.CndSet("Dir","/");
+   
+   // State
+   Cnf.CndSet("Dir::State", &STATE_DIR[1]);
+   Cnf.CndSet("Dir::State::lists","lists/");
+   Cnf.CndSet("Dir::State::cdroms","cdroms.list");
+
+   // Cache
+   Cnf.CndSet("Dir::Cache", &CACHE_DIR[1]);
+   Cnf.CndSet("Dir::Cache::archives","archives/");
+   Cnf.CndSet("Dir::Cache::srcpkgcache","srcpkgcache.bin");
+   Cnf.CndSet("Dir::Cache::pkgcache","pkgcache.bin");
+
+   // Configuration
+   Cnf.CndSet("Dir::Etc", &CONF_DIR[1]);
+   Cnf.CndSet("Dir::Etc::sourcelist","sources.list");
+   Cnf.CndSet("Dir::Etc::sourceparts","sources.list.d");
+   Cnf.CndSet("Dir::Etc::main","apt.conf");
+   Cnf.CndSet("Dir::Etc::netrc", "auth.conf");
+   Cnf.CndSet("Dir::Etc::netrcparts", "auth.conf.d");
+   Cnf.CndSet("Dir::Etc::parts","apt.conf.d");
+   Cnf.CndSet("Dir::Etc::preferences","preferences");
+   Cnf.CndSet("Dir::Etc::preferencesparts","preferences.d");
+   Cnf.CndSet("Dir::Etc::trusted", "trusted.gpg");
+   Cnf.CndSet("Dir::Etc::trustedparts","trusted.gpg.d");
+   Cnf.CndSet("Dir::Bin::methods", LIBEXEC_DIR "/methods");
+   Cnf.CndSet("Dir::Bin::solvers::",LIBEXEC_DIR  "/solvers");
+   Cnf.CndSet("Dir::Bin::planners::",LIBEXEC_DIR  "/planners");
+   Cnf.CndSet("Dir::Media::MountPath","/media/apt");
+
+   // State
+   Cnf.CndSet("Dir::Log", &LOG_DIR[1]);
+   Cnf.CndSet("Dir::Log::Terminal","term.log");
+   Cnf.CndSet("Dir::Log::History","history.log");
+   Cnf.CndSet("Dir::Log::Planner","eipp.log.xz");
+
+   Cnf.Set("Dir::Ignore-Files-Silently::", "~$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.disabled$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.bak$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.dpkg-[a-z]+$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.ucf-[a-z]+$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.save$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.orig$");
+   Cnf.Set("Dir::Ignore-Files-Silently::", "\\.distUpgrade$");
+
+   // Repository security
+   Cnf.CndSet("Acquire::AllowInsecureRepositories", false);
+   Cnf.CndSet("Acquire::AllowWeakRepositories", false);
+   Cnf.CndSet("Acquire::AllowDowngradeToInsecureRepositories", false);
+
+   // Default cdrom mount point
+   Cnf.CndSet("Acquire::cdrom::mount", "/media/cdrom/");
+
+   // The default user we drop to in the methods
+   Cnf.CndSet("APT::Sandbox::User", "_apt");
+
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::MetaKey", "$(COMPONENT)/binary-$(ARCHITECTURE)/Packages");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::flatMetaKey", "Packages");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::ShortDescription", "Packages");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::Description", "$(RELEASE)/$(COMPONENT) $(ARCHITECTURE) Packages");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::flatDescription", "$(RELEASE) Packages");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Packages::Optional", false);
+   Cnf.CndSet("Acquire::IndexTargets::deb::Translations::MetaKey", "$(COMPONENT)/i18n/Translation-$(LANGUAGE)");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Translations::flatMetaKey", "$(LANGUAGE)");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Translations::ShortDescription", "Translation-$(LANGUAGE)");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Translations::Description", "$(RELEASE)/$(COMPONENT) Translation-$(LANGUAGE)");
+   Cnf.CndSet("Acquire::IndexTargets::deb::Translations::flatDescription", "$(RELEASE) Translation-$(LANGUAGE)");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::MetaKey", "$(COMPONENT)/source/Sources");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::flatMetaKey", "Sources");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::ShortDescription", "Sources");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::Description", "$(RELEASE)/$(COMPONENT) Sources");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::flatDescription", "$(RELEASE) Sources");
+   Cnf.CndSet("Acquire::IndexTargets::deb-src::Sources::Optional", false);
+
+   Cnf.CndSet("Acquire::Changelogs::URI::Origin::Debian", "https://metadata.ftp-master.debian.org/changelogs/@CHANGEPATH@_changelog");
+   Cnf.CndSet("Acquire::Changelogs::URI::Origin::Ubuntu", "https://changelogs.ubuntu.com/changelogs/pool/@CHANGEPATH@/changelog");
+   Cnf.CndSet("Acquire::Changelogs::AlwaysOnline::Origin::Ubuntu", true);
+
+
+   Cnf.CndSet("DPkg::Path", "/usr/sbin:/usr/bin:/sbin:/bin");
+
+   // Read an alternate config file
+   _error->PushToStack();
+   const char *Cfg = getenv("APT_CONFIG");
+   if (Cfg != 0 && strlen(Cfg) != 0)
+   {
+      if (RealFileExists(Cfg) == true)
+	 ReadConfigFile(Cnf, Cfg);
+      else
+	 _error->WarningE("RealFileExists",_("Unable to read %s"),Cfg);
+   }
+
+   // Read the configuration parts dir
+   std::string const Parts = Cnf.FindDir("Dir::Etc::parts", "/dev/null");
+   if (DirectoryExists(Parts) == true)
+      ReadConfigDir(Cnf, Parts);
+   else if (APT::String::Endswith(Parts, "/dev/null") == false)
+      _error->WarningE("DirectoryExists",_("Unable to read %s"),Parts.c_str());
+
+   // Read the main config file
+   std::string const FName = Cnf.FindFile("Dir::Etc::main", "/dev/null");
+   if (RealFileExists(FName) == true)
+      ReadConfigFile(Cnf, FName);
+
+   if (Cnf.FindB("Debug::pkgInitConfig",false) == true)
+      Cnf.Dump();
+
+#ifdef APT_DOMAIN
+   if (Cnf.Exists("Dir::Locale"))
+   {
+      bindtextdomain(APT_DOMAIN,Cnf.FindDir("Dir::Locale").c_str());
+      bindtextdomain(textdomain(0),Cnf.FindDir("Dir::Locale").c_str());
+   }
+#endif
+
+   auto const good = _error->PendingError() == false;
+   _error->MergeWithStack();
+   return good;
+}
+									/*}}}*/
+// pkgInitSystem - Initialize the _system class				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgInitSystem(Configuration &Cnf,pkgSystem *&Sys)
+{
+   Sys = 0;
+   std::string Label = Cnf.Find("Apt::System","");
+   if (Label.empty() == false)
+   {
+      Sys = pkgSystem::GetSystem(Label.c_str());
+      if (Sys == 0)
+	 return _error->Error(_("Packaging system '%s' is not supported"),Label.c_str());
+   }
+   else
+   {
+      signed MaxScore = 0;
+      for (unsigned I = 0; I != pkgSystem::GlobalListLen; I++)
+      {
+	 signed Score = pkgSystem::GlobalList[I]->Score(Cnf);
+	 if (Score > MaxScore)
+	 {
+	    MaxScore = Score;
+	    Sys = pkgSystem::GlobalList[I];
+	 }
+      }
+      
+      if (Sys == 0)
+	 return _error->Error(_("Unable to determine a suitable packaging system type"));
+   }
+
+   if (pkgInitArchTupleMap() == false)
+      return false;
+   
+   return Sys->Initialize(Cnf);
+}
+									/*}}}*/
diff --git a/apt-pkg/init.h b/apt-pkg/init.h
new file mode 100644
index 0000000..431e8a5
--- /dev/null
+++ b/apt-pkg/init.h
@@ -0,0 +1,26 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Init - Initialize the package library
+
+   This function must be called to configure the config class before
+   calling many APT library functions.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_INIT_H
+#define PKGLIB_INIT_H
+
+#include <apt-pkg/macros.h>
+
+class pkgSystem;
+class Configuration;
+
+APT_PUBLIC extern const char *pkgVersion;
+APT_PUBLIC extern const char *pkgLibVersion;
+
+APT_PUBLIC bool pkgInitConfig(Configuration &Cnf);
+APT_PUBLIC bool pkgInitSystem(Configuration &Cnf,pkgSystem *&Sys);
+
+#endif
diff --git a/apt-pkg/install-progress.cc b/apt-pkg/install-progress.cc
new file mode 100644
index 0000000..c7f7573
--- /dev/null
+++ b/apt-pkg/install-progress.cc
@@ -0,0 +1,443 @@
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/install-progress.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <cmath>
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+
+namespace APT {
+namespace Progress {
+
+PackageManager::PackageManager() : d(NULL), percentage(0.0), last_reported_progress(-1) {}
+PackageManager::~PackageManager() {}
+
+/* Return a APT::Progress::PackageManager based on the global
+ * apt configuration (i.e. APT::Status-Fd and APT::Status-deb822-Fd)
+ */
+PackageManager* PackageManagerProgressFactory()
+{
+   // select the right progress
+   int status_fd = _config->FindI("APT::Status-Fd", -1);
+   int status_deb822_fd = _config->FindI("APT::Status-deb822-Fd", -1);
+
+   APT::Progress::PackageManager *progress = NULL;
+   if (status_deb822_fd > 0)
+      progress = new APT::Progress::PackageManagerProgressDeb822Fd(
+         status_deb822_fd);
+   else if (status_fd > 0)
+      progress = new APT::Progress::PackageManagerProgressFd(status_fd);
+   else if(_config->FindB("Dpkg::Progress-Fancy", false) == true)
+      progress = new APT::Progress::PackageManagerFancy();
+   else if (_config->FindB("Dpkg::Progress", 
+                           _config->FindB("DpkgPM::Progress", false)) == true)
+      progress = new APT::Progress::PackageManagerText();
+   else
+      progress = new APT::Progress::PackageManager();
+   return progress;
+}
+
+bool PackageManager::StatusChanged(std::string /*PackageName*/,
+                                   unsigned int StepsDone,
+                                   unsigned int TotalSteps,
+                                   std::string /*HumanReadableAction*/)
+{
+   int reporting_steps = _config->FindI("DpkgPM::Reporting-Steps", 1);
+   percentage = StepsDone/(double)TotalSteps * 100.0;
+   strprintf(progress_str, _("Progress: [%3li%%]"), std::lround(percentage));
+
+   if(percentage < (last_reported_progress + reporting_steps))
+      return false;
+
+   return true;
+}
+
+PackageManagerProgressFd::PackageManagerProgressFd(int progress_fd)
+   : d(NULL), StepsDone(0), StepsTotal(1)
+{
+   OutStatusFd = progress_fd;
+}
+PackageManagerProgressFd::~PackageManagerProgressFd() {}
+
+void PackageManagerProgressFd::WriteToStatusFd(std::string s)
+{
+   if(OutStatusFd <= 0)
+      return;
+   FileFd::Write(OutStatusFd, s.c_str(), s.size());   
+}
+
+static std::string GetProgressFdString(char const * const status,
+      char const * const pkg, unsigned long long Done,
+      unsigned long long Total, char const * const msg)
+{
+   float const progress{Done / static_cast<float>(Total) * 100};
+   std::ostringstream str;
+   str.imbue(std::locale::classic());
+   str.precision(4);
+   str << status << ':' << pkg << ':' << std::fixed << progress << ':' << msg << '\n';
+   return str.str();
+}
+
+void PackageManagerProgressFd::StartDpkg()
+{
+   if(OutStatusFd <= 0)
+      return;
+
+   // FIXME: use SetCloseExec here once it taught about throwing
+   //        exceptions instead of doing _exit(100) on failure
+   fcntl(OutStatusFd,F_SETFD,FD_CLOEXEC); 
+
+   // send status information that we are about to fork dpkg
+   WriteToStatusFd(GetProgressFdString("pmstatus", "dpkg-exec", StepsDone, StepsTotal, _("Running dpkg")));
+}
+
+void PackageManagerProgressFd::Stop()
+{
+}
+
+void PackageManagerProgressFd::Error(std::string PackageName,
+                                     unsigned int StepsDone,
+                                     unsigned int TotalSteps,
+                                     std::string ErrorMessage)
+{
+   WriteToStatusFd(GetProgressFdString("pmerror", PackageName.c_str(),
+	    StepsDone, TotalSteps, ErrorMessage.c_str()));
+}
+
+void PackageManagerProgressFd::ConffilePrompt(std::string PackageName,
+                                              unsigned int StepsDone,
+                                              unsigned int TotalSteps,
+                                              std::string ConfMessage)
+{
+   WriteToStatusFd(GetProgressFdString("pmconffile", PackageName.c_str(),
+	    StepsDone, TotalSteps, ConfMessage.c_str()));
+}
+
+
+bool PackageManagerProgressFd::StatusChanged(std::string PackageName, 
+                                             unsigned int xStepsDone,
+                                             unsigned int xTotalSteps,
+                                             std::string pkg_action)
+{
+   StepsDone = xStepsDone;
+   StepsTotal = xTotalSteps;
+
+   WriteToStatusFd(GetProgressFdString("pmstatus", StringSplit(PackageName, ":")[0].c_str(),
+	    StepsDone, StepsTotal, pkg_action.c_str()));
+
+   if(_config->FindB("Debug::APT::Progress::PackageManagerFd", false) == true)
+      std::cerr << "progress: " << PackageName << " " << xStepsDone
+                << " " << xTotalSteps << " " << pkg_action
+                << std::endl;
+
+
+   return true;
+}
+
+
+PackageManagerProgressDeb822Fd::PackageManagerProgressDeb822Fd(int progress_fd)
+   : d(NULL), StepsDone(0), StepsTotal(1)
+{
+   OutStatusFd = progress_fd;
+}
+PackageManagerProgressDeb822Fd::~PackageManagerProgressDeb822Fd() {}
+
+void PackageManagerProgressDeb822Fd::WriteToStatusFd(std::string s)
+{
+   FileFd::Write(OutStatusFd, s.c_str(), s.size());   
+}
+
+static std::string GetProgressDeb822String(char const * const status,
+      char const * const pkg, unsigned long long Done,
+      unsigned long long Total, char const * const msg)
+{
+   float const progress{Done / static_cast<float>(Total) * 100};
+   std::ostringstream str;
+   str.imbue(std::locale::classic());
+   str.precision(4);
+   str << "Status: " << status << '\n';
+   if (pkg != nullptr)
+      str << "Package: " << pkg << '\n';
+   str << "Percent: " << std::fixed << progress << '\n'
+      << "Message: " << msg << "\n\n";
+   return str.str();
+}
+
+void PackageManagerProgressDeb822Fd::StartDpkg()
+{
+   // FIXME: use SetCloseExec here once it taught about throwing
+   //        exceptions instead of doing _exit(100) on failure
+   fcntl(OutStatusFd,F_SETFD,FD_CLOEXEC); 
+
+   WriteToStatusFd(GetProgressDeb822String("progress", nullptr, StepsDone, StepsTotal, _("Running dpkg")));
+}
+
+void PackageManagerProgressDeb822Fd::Stop()
+{
+}
+
+void PackageManagerProgressDeb822Fd::Error(std::string PackageName,
+                                     unsigned int StepsDone,
+                                     unsigned int TotalSteps,
+                                     std::string ErrorMessage)
+{
+   WriteToStatusFd(GetProgressDeb822String("Error", PackageName.c_str(), StepsDone, TotalSteps, ErrorMessage.c_str()));
+}
+
+void PackageManagerProgressDeb822Fd::ConffilePrompt(std::string PackageName,
+                                              unsigned int StepsDone,
+                                              unsigned int TotalSteps,
+                                              std::string ConfMessage)
+{
+   WriteToStatusFd(GetProgressDeb822String("ConfFile", PackageName.c_str(), StepsDone, TotalSteps, ConfMessage.c_str()));
+}
+
+
+bool PackageManagerProgressDeb822Fd::StatusChanged(std::string PackageName, 
+                                             unsigned int xStepsDone,
+                                             unsigned int xTotalSteps,
+                                             std::string message)
+{
+   StepsDone = xStepsDone;
+   StepsTotal = xTotalSteps;
+
+   WriteToStatusFd(GetProgressDeb822String("progress", PackageName.c_str(), StepsDone, StepsTotal, message.c_str()));
+   return true;
+}
+
+
+PackageManagerFancy::PackageManagerFancy()
+   : d(NULL), child_pty(-1)
+{
+   // setup terminal size
+   if (instances.empty())
+      SIGWINCH_orig = signal(SIGWINCH, PackageManagerFancy::staticSIGWINCH);
+   instances.push_back(this);
+}
+std::vector<PackageManagerFancy*> PackageManagerFancy::instances;
+sighandler_t PackageManagerFancy::SIGWINCH_orig;
+volatile sig_atomic_t PackageManagerFancy::SIGWINCH_flag = 0;
+
+PackageManagerFancy::~PackageManagerFancy()
+{
+   instances.erase(find(instances.begin(), instances.end(), this));
+   if (instances.empty())
+      signal(SIGWINCH, SIGWINCH_orig);
+}
+
+void PackageManagerFancy::staticSIGWINCH(int /*signum*/)
+{
+   SIGWINCH_flag = 1;
+}
+
+void PackageManagerFancy::CheckSIGWINCH()
+{
+   if (SIGWINCH_flag)
+   {
+      SIGWINCH_flag = 0;
+      int errsv = errno;
+      int const nr_terminal_rows = GetTerminalSize().rows;
+      SetupTerminalScrollArea(nr_terminal_rows);
+      DrawStatusLine();
+      errno = errsv;
+   }
+}
+
+void PackageManagerFancy::Pulse()
+{
+   CheckSIGWINCH();
+}
+
+PackageManagerFancy::TermSize
+PackageManagerFancy::GetTerminalSize()
+{
+   struct winsize win;
+   PackageManagerFancy::TermSize s = { 0, 0 };
+
+   // FIXME: get from "child_pty" instead?
+   if(ioctl(STDOUT_FILENO, TIOCGWINSZ, (char *)&win) != 0)
+      return s;
+
+   if(_config->FindB("Debug::InstallProgress::Fancy", false) == true)
+      std::cerr << "GetTerminalSize: " << win.ws_row << " x " << win.ws_col << std::endl;
+
+   s.rows = win.ws_row;
+   s.columns = win.ws_col;
+   return s;
+}
+
+void PackageManagerFancy::SetupTerminalScrollArea(int nr_rows)
+{
+     if(_config->FindB("Debug::InstallProgress::Fancy", false) == true)
+        std::cerr << "SetupTerminalScrollArea: " << nr_rows << std::endl;
+
+     if (unlikely(nr_rows <= 1))
+	return;
+
+     // scroll down a bit to avoid visual glitch when the screen
+     // area shrinks by one row
+     std::cout << "\n";
+         
+     // save cursor
+     std::cout << "\0337";
+         
+     // set scroll region (this will place the cursor in the top left)
+     std::cout << "\033[0;" << std::to_string(nr_rows - 1) << "r";
+            
+     // restore cursor but ensure its inside the scrolling area
+     std::cout << "\0338";
+     static const char *move_cursor_up = "\033[1A";
+     std::cout << move_cursor_up;
+
+     // ensure its flushed
+     std::flush(std::cout);
+
+     // setup tty size to ensure xterm/linux console are working properly too
+     // see bug #731738
+     struct winsize win;
+     if (ioctl(child_pty, TIOCGWINSZ, (char *)&win) != -1)
+     {
+	win.ws_row = nr_rows - 1;
+	ioctl(child_pty, TIOCSWINSZ, (char *)&win);
+     }
+}
+
+void PackageManagerFancy::HandleSIGWINCH(int)
+{
+   // for abi compatibility, do not use
+}
+
+void PackageManagerFancy::Start(int a_child_pty)
+{
+   child_pty = a_child_pty;
+   int const nr_terminal_rows = GetTerminalSize().rows;
+   SetupTerminalScrollArea(nr_terminal_rows);
+}
+
+void PackageManagerFancy::Stop()
+{
+   int const nr_terminal_rows = GetTerminalSize().rows;
+   if (nr_terminal_rows > 0)
+   {
+      SetupTerminalScrollArea(nr_terminal_rows + 1);
+
+      // override the progress line (sledgehammer)
+      static const char* clear_screen_below_cursor = "\033[J";
+      std::cout << clear_screen_below_cursor;
+      std::flush(std::cout);
+   }
+   child_pty = -1;
+}
+
+std::string 
+PackageManagerFancy::GetTextProgressStr(float Percent, int OutputSize)
+{
+   std::string output;
+   if (unlikely(OutputSize < 3))
+      return output;
+
+   int const BarSize = OutputSize - 2; // bar without the leading "[" and trailing "]"
+   int const BarDone = std::max(0, std::min(BarSize, static_cast<int>(std::floor(Percent * BarSize))));
+   output.append("[");
+   std::fill_n(std::fill_n(std::back_inserter(output), BarDone, '#'), BarSize - BarDone, '.');
+   output.append("]");
+   return output;
+}
+
+bool PackageManagerFancy::StatusChanged(std::string PackageName, 
+                                        unsigned int StepsDone,
+                                        unsigned int TotalSteps,
+                                        std::string HumanReadableAction)
+{
+   if (!PackageManager::StatusChanged(PackageName, StepsDone, TotalSteps,
+          HumanReadableAction))
+      return false;
+
+   return DrawStatusLine();
+}
+bool PackageManagerFancy::DrawStatusLine()
+{
+   PackageManagerFancy::TermSize const size = GetTerminalSize();
+   if (unlikely(size.rows < 1 || size.columns < 1))
+      return false;
+
+   static std::string save_cursor = "\0337";
+   static std::string restore_cursor = "\0338";
+
+   // green
+   static std::string set_bg_color = DeQuoteString(
+      _config->Find("Dpkg::Progress-Fancy::Progress-fg", "%1b[42m"));
+   // black
+   static std::string set_fg_color = DeQuoteString(
+      _config->Find("Dpkg::Progress-Fancy::Progress-bg", "%1b[30m"));
+
+   static std::string restore_bg =  "\033[49m";
+   static std::string restore_fg = "\033[39m";
+
+   std::cout << save_cursor
+      // move cursor position to last row
+             << "\033[" << std::to_string(size.rows) << ";0f"
+             << set_bg_color
+             << set_fg_color
+             << progress_str
+             << restore_bg
+             << restore_fg;
+   std::flush(std::cout);
+
+   // draw text progress bar
+   if (_config->FindB("Dpkg::Progress-Fancy::Progress-Bar", true))
+   {
+      int padding = 4;
+      auto const progressbar_size = size.columns - padding - String::DisplayLength(progress_str);
+      auto const current_percent = percentage / 100.0f;
+      std::cout << " " 
+                << GetTextProgressStr(current_percent, progressbar_size)
+                << " ";
+      std::flush(std::cout);
+   }
+
+   // restore
+   std::cout << restore_cursor;
+   std::flush(std::cout);
+
+   last_reported_progress = percentage;
+
+   return true;
+}
+
+bool PackageManagerText::StatusChanged(std::string PackageName, 
+                                       unsigned int StepsDone,
+                                       unsigned int TotalSteps,
+                                       std::string HumanReadableAction)
+{
+   if (!PackageManager::StatusChanged(PackageName, StepsDone, TotalSteps, HumanReadableAction))
+      return false;
+
+   std::cout << progress_str << "\r\n";
+   std::flush(std::cout);
+                   
+   last_reported_progress = percentage;
+
+   return true;
+}
+
+PackageManagerText::PackageManagerText() : PackageManager(), d(NULL) {}
+PackageManagerText::~PackageManagerText() {}
+
+
+
+
+} // namespace progress
+} // namespace apt
diff --git a/apt-pkg/install-progress.h b/apt-pkg/install-progress.h
new file mode 100644
index 0000000..617ce2a
--- /dev/null
+++ b/apt-pkg/install-progress.h
@@ -0,0 +1,180 @@
+#ifndef PKGLIB_IPROGRESS_H
+#define PKGLIB_IPROGRESS_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+#include <vector>
+#include <signal.h>
+#include <unistd.h>
+
+namespace APT {
+namespace Progress {
+
+ class PackageManager;
+ APT_PUBLIC PackageManager* PackageManagerProgressFactory();
+
+ class APT_PUBLIC PackageManager
+ {
+ private:
+    /** \brief dpointer placeholder */
+    void * const d;
+
+ protected:
+    std::string progress_str;
+    float percentage;
+    int last_reported_progress;
+
+ public:
+    PackageManager();
+    virtual ~PackageManager();
+
+    /* Global Start/Stop */
+    virtual void Start(int /*child_pty*/=-1) {};
+    virtual void Stop() {};
+
+    /* When dpkg is invoked (may happen multiple times for each
+     * install/remove block
+    */
+    virtual void StartDpkg() {};
+
+    virtual pid_t fork() {return ::fork(); };
+
+    virtual void Pulse() {};
+    virtual long GetPulseInterval() {
+         return 50000000;
+    };
+
+    virtual bool StatusChanged(std::string PackageName,
+                               unsigned int StepsDone,
+                               unsigned int TotalSteps,
+                               std::string HumanReadableAction);
+    virtual void Error(std::string /*PackageName*/,
+                       unsigned int /*StepsDone*/,
+                       unsigned int /*TotalSteps*/,
+                       std::string /*ErrorMessage*/) {}
+    virtual void ConffilePrompt(std::string /*PackageName*/,
+                                unsigned int /*StepsDone*/,
+                                unsigned int /*TotalSteps*/,
+                                std::string /*ConfMessage*/) {}
+ };
+
+ class APT_PUBLIC PackageManagerProgressFd : public PackageManager
+ {
+    void * const d;
+ protected:
+    int OutStatusFd;
+    int StepsDone;
+    int StepsTotal;
+    void WriteToStatusFd(std::string msg);
+
+ public:
+    explicit PackageManagerProgressFd(int progress_fd);
+    virtual ~PackageManagerProgressFd();
+
+    virtual void StartDpkg() APT_OVERRIDE;
+    virtual void Stop() APT_OVERRIDE;
+
+    virtual bool StatusChanged(std::string PackageName,
+                               unsigned int StepsDone,
+                               unsigned int TotalSteps,
+                               std::string HumanReadableAction) APT_OVERRIDE;
+    virtual void Error(std::string PackageName,
+                       unsigned int StepsDone,
+                       unsigned int TotalSteps,
+                          std::string ErrorMessage) APT_OVERRIDE;
+    virtual void ConffilePrompt(std::string PackageName,
+                                unsigned int StepsDone,
+                                unsigned int TotalSteps,
+                                   std::string ConfMessage) APT_OVERRIDE;
+
+ };
+
+ class APT_PUBLIC PackageManagerProgressDeb822Fd : public PackageManager
+ {
+    void * const d;
+ protected:
+    int OutStatusFd;
+    int StepsDone;
+    int StepsTotal;
+    void WriteToStatusFd(std::string msg);
+
+ public:
+    explicit PackageManagerProgressDeb822Fd(int progress_fd);
+    virtual ~PackageManagerProgressDeb822Fd();
+
+    virtual void StartDpkg() APT_OVERRIDE;
+    virtual void Stop() APT_OVERRIDE;
+
+    virtual bool StatusChanged(std::string PackageName,
+                               unsigned int StepsDone,
+                               unsigned int TotalSteps,
+                               std::string HumanReadableAction) APT_OVERRIDE;
+    virtual void Error(std::string PackageName,
+                       unsigned int StepsDone,
+                       unsigned int TotalSteps,
+                          std::string ErrorMessage) APT_OVERRIDE;
+    virtual void ConffilePrompt(std::string PackageName,
+                                unsigned int StepsDone,
+                                unsigned int TotalSteps,
+                                   std::string ConfMessage) APT_OVERRIDE;
+ };
+
+ class APT_PUBLIC PackageManagerFancy : public PackageManager
+ {
+    void * const d;
+ private:
+    APT_HIDDEN static void staticSIGWINCH(int);
+    static std::vector<PackageManagerFancy*> instances;
+    static sighandler_t SIGWINCH_orig;
+    static volatile sig_atomic_t SIGWINCH_flag;
+    APT_HIDDEN void CheckSIGWINCH();
+    APT_HIDDEN bool DrawStatusLine();
+
+ protected:
+    void SetupTerminalScrollArea(int nr_rows);
+    void HandleSIGWINCH(int); // for abi compatibility, do not use
+
+    typedef struct {
+       int rows;
+       int columns;
+    } TermSize;
+    TermSize GetTerminalSize();
+
+    sighandler_t old_SIGWINCH; // for abi compatibility, do not use
+    int child_pty;
+
+ public:
+    PackageManagerFancy();
+    virtual ~PackageManagerFancy();
+    virtual void Pulse() APT_OVERRIDE;
+    virtual void Start(int child_pty=-1) APT_OVERRIDE;
+    virtual void Stop() APT_OVERRIDE;
+    virtual bool StatusChanged(std::string PackageName,
+                               unsigned int StepsDone,
+                               unsigned int TotalSteps,
+                               std::string HumanReadableAction) APT_OVERRIDE;
+
+    // return a progress bar of the given size for the given progress 
+    // percent between 0.0 and 1.0 in the form "[####...]"
+    static std::string GetTextProgressStr(float percent, int OutputSize);
+ };
+
+ class APT_PUBLIC PackageManagerText : public PackageManager
+ {
+    void * const d;
+ public:
+    virtual bool StatusChanged(std::string PackageName,
+                               unsigned int StepsDone,
+                               unsigned int TotalSteps,
+                               std::string HumanReadableAction) APT_OVERRIDE;
+
+    PackageManagerText();
+    virtual ~PackageManagerText();
+ };
+
+
+} // namespace Progress
+} // namespace APT
+
+#endif
diff --git a/apt-pkg/metaindex.cc b/apt-pkg/metaindex.cc
new file mode 100644
index 0000000..97996b3
--- /dev/null
+++ b/apt-pkg/metaindex.cc
@@ -0,0 +1,150 @@
+// Include Files                                                       /*{{{*/
+#include <config.h>
+
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/pkgcachegen.h>
+
+#include <apt-pkg/debmetaindex.h>
+
+#include <string>
+#include <vector>
+									/*}}}*/
+
+class metaIndexPrivate							/*{{{*/
+{
+};
+									/*}}}*/
+
+std::string metaIndex::Describe() const
+{
+   return "Release";
+}
+
+pkgCache::RlsFileIterator metaIndex::FindInCache(pkgCache &Cache, bool const) const
+{
+   return pkgCache::RlsFileIterator(Cache);
+}
+
+bool metaIndex::Merge(pkgCacheGenerator &Gen,OpProgress *) const
+{
+   return Gen.SelectReleaseFile("", "");
+}
+
+metaIndex::metaIndex(std::string const &URI, std::string const &Dist,
+      char const * const Type)
+: d(new metaIndexPrivate()), Indexes(NULL), Type(Type), URI(URI), Dist(Dist), Trusted(TRI_UNSET),
+   Date(0), ValidUntil(0), SupportsAcquireByHash(false), LoadedSuccessfully(TRI_UNSET)
+{
+   /* nothing */
+}
+
+metaIndex::~metaIndex()
+{
+   if (Indexes != 0)
+   {
+      for (std::vector<pkgIndexFile *>::iterator I = (*Indexes).begin();
+	    I != (*Indexes).end(); ++I)
+	 delete *I;
+      delete Indexes;
+   }
+   for (auto const &E: Entries)
+      delete E.second;
+   delete d;
+}
+
+// one line Getters for public fields					/*{{{*/
+APT_PURE std::string metaIndex::GetURI() const { return URI; }
+APT_PURE std::string metaIndex::GetDist() const { return Dist; }
+APT_PURE const char* metaIndex::GetType() const { return Type; }
+APT_PURE metaIndex::TriState metaIndex::GetTrusted() const { return Trusted; }
+APT_PURE std::string metaIndex::GetSignedBy() const { return SignedBy; }
+APT_PURE std::string metaIndex::GetOrigin() const { return Origin; }
+APT_PURE std::string metaIndex::GetLabel() const { return Label; }
+APT_PURE std::string metaIndex::GetVersion() const { return Version; }
+APT_PURE std::string metaIndex::GetCodename() const { return Codename; }
+APT_PURE std::string metaIndex::GetSuite() const { return Suite; }
+APT_PURE std::string metaIndex::GetReleaseNotes() const { return ReleaseNotes; }
+APT_PURE signed short metaIndex::GetDefaultPin() const { return DefaultPin; }
+APT_PURE bool metaIndex::GetSupportsAcquireByHash() const { return SupportsAcquireByHash; }
+APT_PURE time_t metaIndex::GetValidUntil() const { return ValidUntil; }
+APT_PURE time_t metaIndex::GetDate() const { return this->Date; }
+APT_PURE metaIndex::TriState metaIndex::GetLoadedSuccessfully() const { return LoadedSuccessfully; }
+APT_PURE std::string metaIndex::GetExpectedDist() const { return Dist; }
+									/*}}}*/
+bool metaIndex::CheckDist(std::string const &MaybeDist) const		/*{{{*/
+{
+   if (MaybeDist.empty() || this->Codename == MaybeDist || this->Suite == MaybeDist)
+      return true;
+
+   std::string Transformed = MaybeDist;
+   if (Transformed == "../project/experimental")
+      Transformed = "experimental";
+
+   auto const pos = Transformed.rfind('/');
+   if (pos != std::string::npos)
+      Transformed = Transformed.substr(0, pos);
+
+   if (Transformed == ".")
+      Transformed.clear();
+
+   return Transformed.empty() || this->Codename == Transformed || this->Suite == Transformed;
+}
+									/*}}}*/
+APT_PURE metaIndex::checkSum *metaIndex::Lookup(std::string const &MetaKey) const /*{{{*/
+{
+   std::map<std::string, metaIndex::checkSum* >::const_iterator sum = Entries.find(MetaKey);
+   if (sum == Entries.end())
+      return NULL;
+   return sum->second;
+}
+									/*}}}*/
+APT_PURE bool metaIndex::Exists(std::string const &MetaKey) const		/*{{{*/
+{
+   return Entries.find(MetaKey) != Entries.end();
+}
+									/*}}}*/
+std::vector<std::string> metaIndex::MetaKeys() const			/*{{{*/
+{
+   std::vector<std::string> keys;
+   std::map<std::string, checkSum *>::const_iterator I = Entries.begin();
+   while(I != Entries.end()) {
+      keys.push_back((*I).first);
+      ++I;
+   }
+   return keys;
+}
+									/*}}}*/
+void metaIndex::swapLoad(metaIndex * const OldMetaIndex)		/*{{{*/
+{
+   std::swap(SignedBy, OldMetaIndex->SignedBy);
+   std::swap(Suite, OldMetaIndex->Suite);
+   std::swap(Codename, OldMetaIndex->Codename);
+   std::swap(Date, OldMetaIndex->Date);
+   std::swap(ValidUntil, OldMetaIndex->ValidUntil);
+   std::swap(SupportsAcquireByHash, OldMetaIndex->SupportsAcquireByHash);
+   std::swap(Entries, OldMetaIndex->Entries);
+   std::swap(LoadedSuccessfully, OldMetaIndex->LoadedSuccessfully);
+
+   OldMetaIndex->Origin = Origin;
+   OldMetaIndex->Label = Label;
+   OldMetaIndex->Version =Version;
+   OldMetaIndex->DefaultPin = DefaultPin;
+}
+									/*}}}*/
+
+bool metaIndex::IsArchitectureSupported(std::string const &) const	/*{{{*/
+{
+   return true;
+}
+									/*}}}*/
+bool metaIndex::IsArchitectureAllSupportedFor(IndexTarget const &) const/*{{{*/
+{
+   return true;
+}
+									/*}}}*/
+bool metaIndex::HasSupportForComponent(std::string const &) const/*{{{*/
+{
+   return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/metaindex.h b/apt-pkg/metaindex.h
new file mode 100644
index 0000000..b8db217
--- /dev/null
+++ b/apt-pkg/metaindex.h
@@ -0,0 +1,115 @@
+#ifndef PKGLIB_METAINDEX_H
+#define PKGLIB_METAINDEX_H
+
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/init.h>
+
+#include <stddef.h>
+
+#include <string>
+#include <vector>
+
+
+class pkgAcquire;
+class IndexTarget;
+class pkgCacheGenerator;
+class OpProgress;
+
+class metaIndexPrivate;
+
+class APT_PUBLIC metaIndex
+{
+public:
+   struct checkSum
+   {
+      std::string MetaKeyFilename;
+      HashStringList Hashes;
+      unsigned long long Size;
+   };
+
+   enum APT_HIDDEN TriState {
+      TRI_YES, TRI_DONTCARE, TRI_NO, TRI_UNSET
+   };
+private:
+   metaIndexPrivate * const d;
+protected:
+   std::vector <pkgIndexFile *> *Indexes;
+   // parsed from the sources.list
+   const char *Type;
+   std::string URI;
+   std::string Dist;
+   TriState Trusted;
+   std::string SignedBy;
+
+   // parsed from a file
+   std::string Suite;
+   std::string Codename;
+   std::string Origin;
+   std::string Label;
+   std::string Version;
+   signed short DefaultPin;
+   std::string ReleaseNotes;
+   time_t Date;
+   time_t ValidUntil;
+   bool SupportsAcquireByHash;
+   std::map<std::string, checkSum *> Entries;
+   TriState LoadedSuccessfully;
+
+public:
+   // Various accessors
+   std::string GetURI() const;
+   std::string GetDist() const;
+   const char* GetType() const;
+   TriState GetTrusted() const;
+   std::string GetSignedBy() const;
+
+   std::string GetOrigin() const;
+   std::string GetLabel() const;
+   std::string GetVersion() const;
+   std::string GetCodename() const;
+   std::string GetSuite() const;
+   std::string GetReleaseNotes() const;
+   signed short GetDefaultPin() const;
+   bool GetSupportsAcquireByHash() const;
+   time_t GetValidUntil() const;
+   time_t GetDate() const;
+   virtual time_t GetNotBefore() const = 0;
+
+   std::string GetExpectedDist() const;
+   bool CheckDist(std::string const &MaybeDist) const;
+
+   // Interface for acquire
+   virtual std::string Describe() const;
+   virtual std::string ArchiveURI(std::string const& File) const = 0;
+   virtual bool GetIndexes(pkgAcquire *Owner, bool const &GetAll=false) = 0;
+   virtual std::vector<IndexTarget> GetIndexTargets() const = 0;
+   virtual std::vector<pkgIndexFile *> *GetIndexFiles() = 0;
+   virtual bool IsTrusted() const = 0;
+   virtual bool Load(std::string const &Filename, std::string * const ErrorText) = 0;
+   /** @return a new metaIndex object based on this one, but without information from #Load */
+   virtual metaIndex * UnloadedClone() const = 0;
+   // the given metaIndex is potentially invalid after this call and should be deleted
+   void swapLoad(metaIndex * const OldMetaIndex);
+
+   // Lookup functions for parsed Hashes
+   checkSum *Lookup(std::string const &MetaKey) const;
+   /** \brief tests if a checksum for this file is available */
+   bool Exists(std::string const &MetaKey) const;
+   std::vector<std::string> MetaKeys() const;
+   TriState GetLoadedSuccessfully() const;
+
+   // Interfaces for pkgCacheGen
+   virtual pkgCache::RlsFileIterator FindInCache(pkgCache &Cache, bool const ModifyCheck) const;
+   virtual bool Merge(pkgCacheGenerator &Gen,OpProgress *Prog) const;
+
+
+   metaIndex(std::string const &URI, std::string const &Dist,
+             char const * const Type);
+   virtual ~metaIndex();
+
+   virtual bool IsArchitectureSupported(std::string const &arch) const;
+   virtual bool IsArchitectureAllSupportedFor(IndexTarget const &target) const;
+   virtual bool HasSupportForComponent(std::string const &component) const;
+};
+
+#endif
diff --git a/apt-pkg/orderlist.cc b/apt-pkg/orderlist.cc
new file mode 100644
index 0000000..49a3126
--- /dev/null
+++ b/apt-pkg/orderlist.cc
@@ -0,0 +1,1138 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Order List - Represents and Manipulates an ordered list of packages.
+   
+   A list of packages can be ordered by a number of conflicting criteria
+   each given a specific priority. Each package also has a set of flags
+   indicating some useful things about it that are derived in the 
+   course of sorting. The pkgPackageManager class uses this class for
+   all of it's installation ordering needs.
+
+   This is a modified version of Manoj's Routine B. It consists of four
+   independent ordering algorithms that can be applied at for different
+   points in the ordering. By applying progressively fewer ordering
+   operations it is possible to give each consideration it's own
+   priority and create an order that satisfies the lowest applicable
+   consideration.
+   
+   The rules for unpacking ordering are:
+    1) Unpacking ignores Depends: on all packages
+    2) Unpacking requires Conflicts: on -ALL- packages to be satisfied
+    3) Unpacking requires PreDepends: on this package only to be satisfied
+    4) Removing requires that no packages depend on the package to be
+       removed.
+   
+   And the rule for configuration ordering is:
+    1) Configuring requires that the Depends: of the package be satisfied
+       Conflicts+PreDepends are ignored because unpacking says they are 
+       already correct [exageration, it does check but we need not be 
+       concerned]
+
+   And some features that are valuable for unpacking ordering.
+     f1) Unpacking a new package should advoid breaking dependencies of
+         configured packages
+     f2) Removal should not require a force, corrolory of f1
+     f3) Unpacking should order by depends rather than fall back to random
+         ordering.  
+   
+   Each of the features can be enabled in the sorting routine at an 
+   arbitrary priority to give quite abit of control over the final unpacking
+   order.
+
+   The rules listed above may never be violated and are called Critical.
+   When a critical rule is violated then a loop condition is recorded
+   and will have to be delt with in the caller.
+
+   The ordering keeps two lists, the main list and the 'After List'. The
+   purpose of the after list is to allow packages to be delayed. This is done
+   by setting the after flag on the package. Any package which requires this
+   package to be ordered before will inherit the after flag and so on. This
+   is used for CD swap ordering where all packages on a second CD have the 
+   after flag set. This forces them and all their dependents to be ordered
+   toward the end.
+   
+   There are complications in this algorithm when presented with cycles.
+   For all known practical cases it works, all cases where it doesn't work
+   is fixable by tweaking the package descriptions. However, it should be
+   possible to improve this further to make some better choices when 
+   presented with cycles. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/orderlist.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <algorithm>
+#include <iostream>
+#include <stdlib.h>
+#include <string.h>
+									/*}}}*/
+
+using namespace std;
+
+// OrderList::pkgOrderList - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgOrderList::pkgOrderList(pkgDepCache *pCache) : d(NULL), Cache(*pCache),
+						  Primary(NULL), Secondary(NULL),
+						  RevDepends(NULL), Remove(NULL),
+						  AfterEnd(NULL), FileList(NULL),
+						  LoopCount(-1), Depth(0)
+{
+   Debug = _config->FindB("Debug::pkgOrderList",false);
+
+   /* Construct the arrays, egcs 1.0.1 bug requires the package count
+      hack */
+   auto const Size = Cache.Head().PackageCount;
+   Flags = new unsigned short[Size];
+   End = List = new Package *[Size];
+   memset(Flags,0,sizeof(*Flags)*Size);
+}
+									/*}}}*/
+// OrderList::~pkgOrderList - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgOrderList::~pkgOrderList()
+{
+   delete [] List;
+   delete [] Flags;
+}
+									/*}}}*/
+// OrderList::IsMissing - Check if a file is missing			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgOrderList::IsMissing(PkgIterator Pkg) 
+{
+   // Skip packages to erase
+   if (Cache[Pkg].Delete() == true)
+      return false;
+
+   // Skip Packages that need configure only.
+   if ((Pkg.State() == pkgCache::PkgIterator::NeedsConfigure ||
+        Pkg.State() == pkgCache::PkgIterator::NeedsNothing) &&
+       Cache[Pkg].Keep() == true)
+      return false;
+
+   if (FileList == 0)
+      return false;
+   
+   if (FileList[Pkg->ID].empty() == false)
+      return false;
+
+   return true;
+}
+									/*}}}*/
+// OrderList::DoRun - Does an order run					/*{{{*/
+// ---------------------------------------------------------------------
+/* The caller is expected to have setup the desired probe state */
+bool pkgOrderList::DoRun()
+{   
+   // Temp list
+   unsigned long Size = Cache.Head().PackageCount;
+   std::unique_ptr<Package *[]> NList(new Package *[Size]);
+   std::unique_ptr<Package *[]> AfterList(new Package *[Size]);
+   AfterEnd = AfterList.get();
+   
+   Depth = 0;
+   WipeFlags(Added | AddPending | Loop | InList);
+
+   for (iterator I = List; I != End; ++I)
+      Flag(*I,InList);
+
+   // Rebuild the main list into the temp list.
+   iterator OldEnd = End;
+   End = NList.get();
+   for (iterator I = List; I != OldEnd; ++I)
+      if (VisitNode(PkgIterator(Cache,*I), "DoRun") == false)
+      {
+	 End = OldEnd;
+	 return false;
+      }
+   
+   // Copy the after list to the end of the main list
+   for (Package **I = AfterList.get(); I != AfterEnd; I++)
+      *End++ = *I;
+   
+   // Swap the main list to the new list
+   delete [] List;
+   List = NList.release();
+   return true;
+}
+									/*}}}*/
+// OrderList::OrderCritical - Perform critical unpacking ordering	/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs predepends and immediate configuration ordering only. 
+   This is termed critical unpacking ordering. Any loops that form are
+   fatal and indicate that the packages cannot be installed. */
+bool pkgOrderList::OrderCritical()
+{
+   FileList = 0;
+
+   Primary = &pkgOrderList::DepUnPackPreD;
+   Secondary = 0;
+   RevDepends = 0;
+   Remove = 0;
+   LoopCount = 0;
+
+   // Sort
+   std::sort(List,End, [this](Package *a, Package *b) { return OrderCompareB(a, b) < 0; } );
+
+   if (DoRun() == false)
+      return false;
+
+   if (LoopCount != 0)
+      return _error->Error("Fatal, predepends looping detected");
+
+   if (Debug == true)
+   {
+      clog << "** Critical Unpack ordering done" << endl;
+
+      for (iterator I = List; I != End; ++I)
+      {
+	 PkgIterator P(Cache,*I);
+	 if (IsNow(P) == true)
+	    clog << "  " << P.FullName() << ' ' << IsMissing(P) << ',' << IsFlag(P,After) << endl;
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+// OrderList::OrderUnpack - Perform complete unpacking ordering		/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs complete unpacking ordering and creates an order that is
+   suitable for unpacking */
+bool pkgOrderList::OrderUnpack(string *FileList)
+{
+   this->FileList = FileList;
+
+   // Setup the after flags
+   if (FileList != 0)
+   {
+      WipeFlags(After);
+
+      // Set the inlist flag
+      for (iterator I = List; I != End; ++I)
+      {
+	 PkgIterator P(Cache,*I);
+	 if (IsMissing(P) == true && IsNow(P) == true)
+	     Flag(*I,After);
+      }
+   }
+
+   Primary = &pkgOrderList::DepUnPackCrit;
+   Secondary = &pkgOrderList::DepConfigure;
+   RevDepends = &pkgOrderList::DepUnPackDep;
+   Remove = &pkgOrderList::DepRemove;
+   LoopCount = -1;
+
+   // Sort
+   std::sort(List,End, [this](Package *a, Package *b) { return OrderCompareA(a, b) < 0; });
+
+   if (Debug == true)
+      clog << "** Pass A" << endl;
+   if (DoRun() == false)
+      return false;
+
+   if (Debug == true)
+      clog << "** Pass B" << endl;
+   Secondary = 0;
+   if (DoRun() == false)
+      return false;
+
+   if (Debug == true)
+      clog << "** Pass C" << endl;
+   LoopCount = 0;
+   RevDepends = 0;
+   Remove = 0;             // Otherwise the libreadline remove problem occurs
+   if (DoRun() == false)
+      return false;
+
+   if (Debug == true)
+      clog << "** Pass D" << endl;
+   LoopCount = 0;
+   Primary = &pkgOrderList::DepUnPackPre;
+   if (DoRun() == false)
+      return false;
+
+   if (Debug == true)
+   {
+      clog << "** Unpack ordering done" << endl;
+
+      for (iterator I = List; I != End; ++I)
+      {
+	 PkgIterator P(Cache,*I);
+	 if (IsNow(P) == true)
+	    clog << "  " << P.FullName() << ' ' << IsMissing(P) << ',' << IsFlag(P,After) << endl;
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+// OrderList::OrderConfigure - Perform configuration ordering		/*{{{*/
+// ---------------------------------------------------------------------
+/* This orders by depends only and produces an order which is suitable
+   for configuration */
+bool pkgOrderList::OrderConfigure()
+{
+   FileList = 0;
+   Primary = &pkgOrderList::DepConfigure;
+   Secondary = 0;
+   RevDepends = 0;
+   Remove = 0;
+   LoopCount = -1;
+   return DoRun();
+}
+									/*}}}*/
+// OrderList::Score - Score the package for sorting			/*{{{*/
+// ---------------------------------------------------------------------
+/* Higher scores order earlier */
+int pkgOrderList::Score(PkgIterator Pkg)
+{
+   // Removals should be done after we dealt with essentials
+   static int const ScoreDelete = _config->FindI("OrderList::Score::Delete", 100);
+   if (Cache[Pkg].Delete() == true)
+      return ScoreDelete;
+
+   // This should never happen..
+   if (Cache[Pkg].InstVerIter(Cache).end() == true)
+      return -1;
+
+   static int const ScoreEssential = _config->FindI("OrderList::Score::Essential", 200);
+   static int const ScoreImmediate = _config->FindI("OrderList::Score::Immediate", 10);
+   static int const ScorePreDepends = _config->FindI("OrderList::Score::PreDepends", 50);
+
+   int Score = 0;
+   if ((Pkg->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+      Score += ScoreEssential;
+
+   if (IsFlag(Pkg,Immediate) == true)
+      Score += ScoreImmediate;
+
+   for (DepIterator D = Cache[Pkg].InstVerIter(Cache).DependsList();
+	D.end() == false; ++D)
+      if (D->Type == pkgCache::Dep::PreDepends)
+      {
+	 Score += ScorePreDepends;
+	 break;
+      }
+
+   // Required Important Standard Optional Extra
+   if (Cache[Pkg].InstVerIter(Cache)->Priority <= 5)
+   {
+      signed short PrioMap[] = {0,5,4,3,1,0};
+      Score += PrioMap[Cache[Pkg].InstVerIter(Cache)->Priority];
+   }
+   return Score;
+}
+									/*}}}*/
+// OrderList::FileCmp - Compare by package file				/*{{{*/
+// ---------------------------------------------------------------------
+/* This compares by the package file that the install version is in. */
+int pkgOrderList::FileCmp(PkgIterator A,PkgIterator B)
+{
+   if (Cache[A].Delete() == true && Cache[B].Delete() == true)
+      return 0;
+   if (Cache[A].Delete() == true)
+      return -1;
+   if (Cache[B].Delete() == true)
+      return 1;
+   
+   if (Cache[A].InstVerIter(Cache).FileList().end() == true)
+      return -1;
+   if (Cache[B].InstVerIter(Cache).FileList().end() == true)
+      return 1;
+   
+   pkgCache::PackageFile *FA = Cache[A].InstVerIter(Cache).FileList().File();
+   pkgCache::PackageFile *FB = Cache[B].InstVerIter(Cache).FileList().File();
+   if (FA < FB)
+      return -1;
+   if (FA > FB)
+      return 1;
+   return 0;
+}
+									/*}}}*/
+// BoolCompare - Comparison function for two booleans			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+static int BoolCompare(bool A,bool B)
+{
+   if (A == B)
+      return 0;
+   if (A == false)
+      return -1;
+   return 1;
+}
+									/*}}}*/
+// OrderList::OrderCompareA - Order the installation by op		/*{{{*/
+// ---------------------------------------------------------------------
+/* This provides a first-pass sort of the list and gives a decent starting
+    point for further complete ordering. It is used by OrderUnpack only */
+int pkgOrderList::OrderCompareA(Package *a, Package *b)
+{
+   PkgIterator A(Cache,a);
+   PkgIterator B(Cache,b);
+
+   // We order packages with a set state toward the front
+   int Res;
+   if ((Res = BoolCompare(IsNow(A),IsNow(B))) != 0)
+      return -1*Res;
+   
+   // We order missing files to toward the end
+/*   if (FileList != 0)
+   {
+      if ((Res = BoolCompare(IsMissing(A),
+			     IsMissing(B))) != 0)
+	 return Res;
+   }*/
+   
+   if (A.State() != pkgCache::PkgIterator::NeedsNothing && 
+       B.State() == pkgCache::PkgIterator::NeedsNothing)
+      return -1;
+
+   if (A.State() == pkgCache::PkgIterator::NeedsNothing && 
+       B.State() != pkgCache::PkgIterator::NeedsNothing)
+      return 1;
+   
+   int ScoreA = Score(A);
+   int ScoreB = Score(B);
+
+   if (ScoreA > ScoreB)
+      return -1;
+   
+   if (ScoreA < ScoreB)
+      return 1;
+
+   return strcmp(A.Name(),B.Name());
+}
+									/*}}}*/
+// OrderList::OrderCompareB - Order the installation by source		/*{{{*/
+// ---------------------------------------------------------------------
+/* This orders by installation source. This is useful to handle
+   inter-source breaks */
+int pkgOrderList::OrderCompareB(Package *a, Package *b)
+{
+   PkgIterator A(Cache,a);
+   PkgIterator B(Cache,b);
+
+   if (A.State() != pkgCache::PkgIterator::NeedsNothing && 
+       B.State() == pkgCache::PkgIterator::NeedsNothing)
+      return -1;
+
+   if (A.State() == pkgCache::PkgIterator::NeedsNothing && 
+       B.State() != pkgCache::PkgIterator::NeedsNothing)
+      return 1;
+   
+   int F = FileCmp(A,B);
+   if (F != 0)
+   {
+      if (F > 0)
+	 return -1;
+      return 1;
+   }
+   
+   int ScoreA = Score(A);
+   int ScoreB = Score(B);
+
+   if (ScoreA > ScoreB)
+      return -1;
+   
+   if (ScoreA < ScoreB)
+      return 1;
+
+   return strcmp(A.Name(),B.Name());
+}
+									/*}}}*/
+// OrderList::VisitDeps - Visit forward install dependencies		/*{{{*/
+// ---------------------------------------------------------------------
+/* This calls the dependency function for the normal forwards dependencies
+   of the package */
+bool pkgOrderList::VisitDeps(DepFunc F,PkgIterator Pkg)
+{
+   if (F == 0 || Pkg.end() == true || Cache[Pkg].InstallVer == 0)
+      return true;
+   
+   return (this->*F)(Cache[Pkg].InstVerIter(Cache).DependsList());
+}
+									/*}}}*/
+// OrderList::VisitRDeps - Visit reverse dependencies			/*{{{*/
+// ---------------------------------------------------------------------
+/* This calls the dependency function for all of the normal reverse depends
+   of the package */
+bool pkgOrderList::VisitRDeps(DepFunc F,PkgIterator Pkg)
+{
+   if (F == 0 || Pkg.end() == true)
+      return true;
+   
+   return (this->*F)(Pkg.RevDependsList());
+}
+									/*}}}*/
+// OrderList::VisitRProvides - Visit provides reverse dependencies	/*{{{*/
+// ---------------------------------------------------------------------
+/* This calls the dependency function for all reverse dependencies
+   generated by the provides line on the package. */
+bool pkgOrderList::VisitRProvides(DepFunc F,VerIterator Ver)
+{
+   if (F == 0 || Ver.end() == true)
+      return true;
+   
+   bool Res = true;
+   for (PrvIterator P = Ver.ProvidesList(); P.end() == false; ++P)
+      Res &= (this->*F)(P.ParentPkg().RevDependsList());
+   return Res;
+}
+									/*}}}*/
+// OrderList::VisitProvides - Visit all of the providing packages	/*{{{*/
+// ---------------------------------------------------------------------
+/* This routine calls visit on all providing packages.
+
+   If the dependency is negative it first visits packages which are
+   intended to be removed and after that all other packages.
+   It does so to avoid situations in which this package is used to
+   satisfy a (or-group/provides) dependency of another package which
+   could have been satisfied also by upgrading another package -
+   otherwise we have more broken packages dpkg needs to auto-
+   deconfigure and in very complicated situations it even decides
+   against it! */
+bool pkgOrderList::VisitProvides(DepIterator D,bool Critical)
+{
+   std::unique_ptr<Version *[]> List(D.AllTargets());
+   for (Version **I = List.get(); *I != 0; ++I)
+   {
+      VerIterator Ver(Cache,*I);
+      PkgIterator Pkg = Ver.ParentPkg();
+
+      if (D.IsNegative() == true && Cache[Pkg].Delete() == false)
+	 continue;
+
+      if (Cache[Pkg].Keep() == true && Pkg.State() == PkgIterator::NeedsNothing)
+	 continue;
+
+      if (D.IsNegative() == false &&
+	  Cache[Pkg].InstallVer != *I)
+	 continue;
+
+      if (D.IsNegative() == true &&
+	  (Version *)Pkg.CurrentVer() != *I)
+	 continue;
+
+      // Skip over missing files
+      if (Critical == false && IsMissing(D.ParentPkg()) == true)
+	 continue;
+
+      if (VisitNode(Pkg, "Provides-1") == false)
+	 return false;
+   }
+   if (D.IsNegative() == false)
+      return true;
+   for (Version **I = List.get(); *I != 0; ++I)
+   {
+      VerIterator Ver(Cache,*I);
+      PkgIterator Pkg = Ver.ParentPkg();
+
+      if (Cache[Pkg].Delete() == true)
+	 continue;
+
+      if (Cache[Pkg].Keep() == true && Pkg.State() == PkgIterator::NeedsNothing)
+	 continue;
+
+      if ((Version *)Pkg.CurrentVer() != *I)
+	 continue;
+
+      // Skip over missing files
+      if (Critical == false && IsMissing(D.ParentPkg()) == true)
+	 continue;
+
+      if (VisitNode(Pkg, "Provides-2") == false)
+	 return false;
+   }
+
+   return true;
+}
+									/*}}}*/
+// OrderList::VisitNode - Recursive ordering director			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is the core ordering routine. It calls the set dependency
+   consideration functions which then potentially call this again. Finite
+   depth is achieved through the colouring mechanism. */
+bool pkgOrderList::VisitNode(PkgIterator Pkg, char const* from)
+{
+   // Looping or irrelevant.
+   // This should probably trancend not installed packages
+   if (Pkg.end() == true || IsFlag(Pkg,Added) == true || 
+       IsFlag(Pkg,AddPending) == true || IsFlag(Pkg,InList) == false)
+      return true;
+
+   if (Debug == true)
+   {
+      for (int j = 0; j != Depth; j++) clog << ' ';
+      clog << "Visit " << Pkg.FullName() << " from " << from << endl;
+   }
+   
+   Depth++;
+   
+   // Color grey
+   Flag(Pkg,AddPending);
+
+   DepFunc Old = Primary;
+   
+   // Perform immediate configuration of the package if so flagged.
+   if (IsFlag(Pkg,Immediate) == true && Primary != &pkgOrderList::DepUnPackPre)
+      Primary = &pkgOrderList::DepUnPackPreD;
+
+   if (IsNow(Pkg) == true)
+   {
+      bool Res = true;
+      if (Cache[Pkg].Delete() == false)
+      {
+	 // Primary
+	 Res &= Res && VisitDeps(Primary,Pkg);
+	 Res &= Res && VisitRDeps(Primary,Pkg);
+	 Res &= Res && VisitRProvides(Primary,Pkg.CurrentVer());
+	 Res &= Res && VisitRProvides(Primary,Cache[Pkg].InstVerIter(Cache));
+	 
+	 // RevDep
+	 Res &= Res && VisitRDeps(RevDepends,Pkg);
+	 Res &= Res && VisitRProvides(RevDepends,Pkg.CurrentVer());
+	 Res &= Res && VisitRProvides(RevDepends,Cache[Pkg].InstVerIter(Cache));
+	 
+	 // Secondary
+	 Res &= Res && VisitDeps(Secondary,Pkg);
+	 Res &= Res && VisitRDeps(Secondary,Pkg);
+	 Res &= Res && VisitRProvides(Secondary,Pkg.CurrentVer());
+	 Res &= Res && VisitRProvides(Secondary,Cache[Pkg].InstVerIter(Cache));
+      }
+      else
+      { 
+	 // RevDep
+	 Res &= Res && VisitRDeps(Remove,Pkg);
+	 Res &= Res && VisitRProvides(Remove,Pkg.CurrentVer());
+      }
+   }
+   
+   if (IsFlag(Pkg,Added) == false)
+   {
+      Flag(Pkg,Added,Added | AddPending);
+      if (IsFlag(Pkg,After) == true)
+	 *AfterEnd++ = Pkg;
+      else
+	 *End++ = Pkg;
+   }
+   
+   Primary = Old;
+   Depth--;
+
+   if (Debug == true)
+   {
+      for (int j = 0; j != Depth; j++) clog << ' ';
+      clog << "Leave " << Pkg.FullName() << ' ' << IsFlag(Pkg,Added) << ',' << IsFlag(Pkg,AddPending) << endl;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// OrderList::DepUnPackCrit - Critical UnPacking ordering		/*{{{*/
+// ---------------------------------------------------------------------
+/* Critical unpacking ordering strives to satisfy Conflicts: and 
+   PreDepends: only. When a prdepends is encountered the Primary 
+   DepFunc is changed to be DepUnPackPreD. 
+
+   Loops are preprocessed and logged. */
+bool pkgOrderList::DepUnPackCrit(DepIterator D)
+{
+   for (; D.end() == false; ++D)
+   {
+      if (D.Reverse() == true)
+      {
+	 /* Reverse depenanices are only interested in conflicts,
+	    predepend breakage is ignored here */
+	 if (D->Type != pkgCache::Dep::Conflicts && 
+	     D->Type != pkgCache::Dep::Obsoletes)
+	    continue;
+
+	 // Duplication elimination, consider only the current version
+	 if (D.ParentPkg().CurrentVer() != D.ParentVer())
+	    continue;
+	 
+	 /* For reverse dependencies we wish to check if the
+	    dependency is satisfied in the install state. The
+	    target package (caller) is going to be in the installed
+	    state. */
+	 if (CheckDep(D) == true)
+	    continue;
+
+	 if (VisitNode(D.ParentPkg(), "UnPackCrit") == false)
+	    return false;
+      }
+      else
+      {
+	 /* Forward critical dependencies MUST be correct before the 
+	    package can be unpacked. */
+	 if (D.IsNegative() == false &&
+	     D->Type != pkgCache::Dep::PreDepends)
+	    continue;
+	 	 	 	 
+	 /* We wish to check if the dep is okay in the now state of the
+	    target package against the install state of this package. */
+	 if (CheckDep(D) == true)
+	 {
+	    /* We want to catch predepends loops with the code below.
+	       Conflicts loops that are Dep OK are ignored */
+	    if (IsFlag(D.TargetPkg(),AddPending) == false ||
+		D->Type != pkgCache::Dep::PreDepends)
+	       continue;
+	 }
+
+	 // This is the loop detection
+	 if (IsFlag(D.TargetPkg(),Added) == true || 
+	     IsFlag(D.TargetPkg(),AddPending) == true)
+	 {
+	    if (IsFlag(D.TargetPkg(),AddPending) == true)
+	       AddLoop(D);
+	    continue;
+	 }
+
+	 /* Predepends require a special ordering stage, they must have
+	    all dependents installed as well */
+	 DepFunc Old = Primary;
+	 bool Res = false;
+	 if (D->Type == pkgCache::Dep::PreDepends)
+	    Primary = &pkgOrderList::DepUnPackPreD;
+	 Res = VisitProvides(D,true);
+	 Primary = Old;
+	 if (Res == false)
+	    return false;
+      }	 
+   }   
+   return true;
+}
+									/*}}}*/
+// OrderList::DepUnPackPreD - Critical UnPacking ordering with depends	/*{{{*/
+// ---------------------------------------------------------------------
+/* Critical PreDepends (also configure immediate and essential) strives to
+   ensure not only that all conflicts+predepends are met but that this
+   package will be immediately configurable when it is unpacked.
+   Loops are preprocessed and logged. */
+bool pkgOrderList::DepUnPackPreD(DepIterator D)
+{
+   if (D.Reverse() == true)
+      return DepUnPackCrit(D);
+   
+   for (; D.end() == false; ++D)
+   {
+      if (D.IsCritical() == false)
+	 continue;
+
+      /* We wish to check if the dep is okay in the now state of the
+         target package against the install state of this package. */
+      if (CheckDep(D) == true)
+      {
+	 /* We want to catch predepends loops with the code below.
+	    Conflicts loops that are Dep OK are ignored */
+	 if (IsFlag(D.TargetPkg(),AddPending) == false ||
+	     D->Type != pkgCache::Dep::PreDepends)
+	    continue;
+      }
+      
+      // This is the loop detection
+      if (IsFlag(D.TargetPkg(),Added) == true || 
+	  IsFlag(D.TargetPkg(),AddPending) == true)
+      {
+	 if (IsFlag(D.TargetPkg(),AddPending) == true)
+	    AddLoop(D);
+	 continue;
+      }
+      
+      if (VisitProvides(D,true) == false)
+	 return false;
+   }   
+   return true;
+}
+									/*}}}*/
+// OrderList::DepUnPackPre - Critical Predepends ordering		/*{{{*/
+// ---------------------------------------------------------------------
+/* Critical PreDepends (also configure immediate and essential) strives to
+   ensure not only that all conflicts+predepends are met but that this
+   package will be immediately configurable when it is unpacked. 
+
+   Loops are preprocessed and logged. All loops will be fatal. */
+bool pkgOrderList::DepUnPackPre(DepIterator D)
+{
+   if (D.Reverse() == true)
+      return true;
+   
+   for (; D.end() == false; ++D)
+   {
+      /* Only consider the PreDepends or Depends. Depends are only
+       	 considered at the lowest depth or in the case of immediate
+       	 configure */
+      if (D->Type != pkgCache::Dep::PreDepends)
+      {
+	 if (D->Type == pkgCache::Dep::Depends)
+	 {
+	    if (Depth == 1 && IsFlag(D.ParentPkg(),Immediate) == false)
+	       continue;
+	 }
+	 else
+	    continue;
+      }
+      
+      /* We wish to check if the dep is okay in the now state of the
+         target package against the install state of this package. */
+      if (CheckDep(D) == true)
+      {
+	 /* We want to catch predepends loops with the code below.
+	    Conflicts loops that are Dep OK are ignored */
+	 if (IsFlag(D.TargetPkg(),AddPending) == false)
+	    continue;
+      }
+
+      // This is the loop detection
+      if (IsFlag(D.TargetPkg(),Added) == true || 
+	  IsFlag(D.TargetPkg(),AddPending) == true)
+      {
+	 if (IsFlag(D.TargetPkg(),AddPending) == true)
+	    AddLoop(D);
+	 continue;
+      }
+      
+      if (VisitProvides(D,true) == false)
+	 return false;
+   }   
+   return true;
+}
+									/*}}}*/
+// OrderList::DepUnPackDep - Reverse dependency considerations		/*{{{*/
+// ---------------------------------------------------------------------
+/* Reverse dependencies are considered to determine if unpacking this
+   package will break any existing dependencies. If so then those
+   packages are ordered before this one so that they are in the
+   UnPacked state. 
+ 
+   The forwards depends loop is designed to bring the packages dependents
+   close to the package. This helps reduce deconfigure time. 
+   
+   Loops are irrelevant to this. */
+bool pkgOrderList::DepUnPackDep(DepIterator D)
+{
+   
+   for (; D.end() == false; ++D)
+      if (D.IsCritical() == true)
+      {
+	 if (D.Reverse() == true)
+	 {
+	    /* Duplication prevention. We consider rev deps only on
+	       the current version, a not installed package
+	       cannot break */
+	    if (D.ParentPkg()->CurrentVer == 0 ||
+		D.ParentPkg().CurrentVer() != D.ParentVer())
+	       continue;
+
+	    // The dep will not break so it is irrelevant.
+	    if (CheckDep(D) == true)
+	       continue;
+	    
+	    // Skip over missing files
+	    if (IsMissing(D.ParentPkg()) == true)
+	       continue;
+	    
+	    if (VisitNode(D.ParentPkg(), "UnPackDep-Parent") == false)
+	       return false;
+	 }
+	 else
+	 {
+	    if (D->Type == pkgCache::Dep::Depends)
+	       if (VisitProvides(D,false) == false)
+		  return false;
+
+	    if (D->Type == pkgCache::Dep::DpkgBreaks)
+	    {
+	       if (CheckDep(D) == true)
+		 continue;
+
+	       if (VisitNode(D.TargetPkg(), "UnPackDep-Target") == false)
+		 return false;
+	    }
+	 }
+      }
+   return true;
+}
+									/*}}}*/
+// OrderList::DepConfigure - Configuration ordering			/*{{{*/
+// ---------------------------------------------------------------------
+/* Configuration only ordering orders by the Depends: line only. It
+   orders configuration so that when a package comes to be configured it's
+   dependents are configured. 
+ 
+   Loops are ignored. Depends loop entry points are chaotic. */
+bool pkgOrderList::DepConfigure(DepIterator D)
+{
+   // Never consider reverse configuration dependencies.
+   if (D.Reverse() == true)
+      return true;
+   
+   for (; D.end() == false; ++D)
+      if (D->Type == pkgCache::Dep::Depends)
+	 if (VisitProvides(D,false) == false)
+	    return false;
+   return true;
+}
+									/*}}}*/
+// OrderList::DepRemove - Removal ordering				/*{{{*/
+// ---------------------------------------------------------------------
+/* Checks all given dependencies if they are broken by the removal of a
+   package and if so fix it by visiting another provider or or-group
+   member to ensure that the dependee keeps working which is especially
+   important for Immediate packages like e.g. those depending on an
+   awk implementation. If the dependency can't be fixed with another
+   package this means an upgrade of the package will solve the problem. */
+bool pkgOrderList::DepRemove(DepIterator Broken)
+{
+   if (Broken.Reverse() == false)
+      return true;
+
+   for (; Broken.end() == false; ++Broken)
+   {
+      if (Broken->Type != pkgCache::Dep::Depends &&
+	    Broken->Type != pkgCache::Dep::PreDepends)
+	 continue;
+
+      PkgIterator BrokenPkg = Broken.ParentPkg();
+      // uninstalled packages can't break via a remove
+      if (BrokenPkg->CurrentVer == 0)
+	 continue;
+
+      // if its already added, we can't do anything useful
+      if (IsFlag(BrokenPkg, AddPending) == true || IsFlag(BrokenPkg, Added) == true)
+	 continue;
+
+      // if the dependee is going to be removed, visit it now
+      if (Cache[BrokenPkg].Delete() == true)
+	 return VisitNode(BrokenPkg, "Remove-Dependee");
+
+      // The package stays around, so find out how this is possible
+      for (DepIterator D = BrokenPkg.CurrentVer().DependsList(); D.end() == false;)
+      {
+	 // only important or-groups need fixing
+	 if (D->Type != pkgCache::Dep::Depends &&
+	       D->Type != pkgCache::Dep::PreDepends)
+	 {
+	    ++D;
+	    continue;
+	 }
+
+	 // Start is the beginning of the or-group, D is the first one after or
+	 DepIterator Start = D;
+	 bool foundBroken = false;
+	 for (bool LastOR = true; D.end() == false && LastOR == true; ++D)
+	 {
+	    LastOR = (D->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or;
+	    if (D == Broken)
+	       foundBroken = true;
+	 }
+
+	 // this or-group isn't the broken one: keep searching
+	 if (foundBroken == false)
+	    continue;
+
+	 // iterate over all members of the or-group searching for a ready replacement
+	 bool readyReplacement = false;
+	 for (DepIterator OrMember = Start; OrMember != D && readyReplacement == false; ++OrMember)
+	 {
+	    Version ** Replacements = OrMember.AllTargets();
+	    for (Version **R = Replacements; *R != 0; ++R)
+	    {
+	       VerIterator Ver(Cache,*R);
+	       // only currently installed packages can be a replacement
+	       PkgIterator RPkg = Ver.ParentPkg();
+	       if (RPkg.CurrentVer() != Ver)
+		  continue;
+
+	       // packages going to be removed can't be a replacement
+	       if (Cache[RPkg].Delete() == true)
+		  continue;
+
+	       readyReplacement = true;
+	       break;
+	    }
+	    delete[] Replacements;
+	 }
+
+	 // something else is ready to take over, do nothing
+	 if (readyReplacement == true)
+	    continue;
+
+	 // see if we can visit a replacement
+	 bool visitReplacement = false;
+	 for (DepIterator OrMember = Start; OrMember != D && visitReplacement == false; ++OrMember)
+	 {
+	    Version ** Replacements = OrMember.AllTargets();
+	    for (Version **R = Replacements; *R != 0; ++R)
+	    {
+	       VerIterator Ver(Cache,*R);
+	       // consider only versions we plan to install
+	       PkgIterator RPkg = Ver.ParentPkg();
+	       if (Cache[RPkg].Install() == false || Cache[RPkg].InstallVer != Ver)
+		  continue;
+
+	       // loops are not going to help us, so don't create them
+	       if (IsFlag(RPkg, AddPending) == true)
+		  continue;
+
+	       if (IsMissing(RPkg) == true)
+		  continue;
+
+	       visitReplacement = true;
+	       if (IsFlag(BrokenPkg, Immediate) == false)
+	       {
+		  if (VisitNode(RPkg, "Remove-Rep") == true)
+		     break;
+	       }
+	       else
+	       {
+		  Flag(RPkg, Immediate);
+		  if (VisitNode(RPkg, "Remove-ImmRep") == true)
+		     break;
+	       }
+	       visitReplacement = false;
+	    }
+	    delete[] Replacements;
+	 }
+	 if (visitReplacement == true)
+	    continue;
+
+	 // the broken package in current version can't be fixed, so install new version
+	 if (IsMissing(BrokenPkg) == true)
+	    break;
+
+	 if (VisitNode(BrokenPkg, "Remove-Upgrade") == false)
+	    return false;
+      }
+   }
+
+   return true;
+}
+									/*}}}*/
+// OrderList::AddLoop - Add a loop to the loop list			/*{{{*/
+// ---------------------------------------------------------------------
+/* We record the loops. This is a relic since loop breaking is done 
+   genericaly as part of the safety routines. */
+bool pkgOrderList::AddLoop(DepIterator D)
+{
+   if (LoopCount < 0 || LoopCount >= 20)
+      return false;  
+   
+   // Skip dups
+   if (LoopCount != 0)
+   {
+      if (Loops[LoopCount - 1].ParentPkg() == D.ParentPkg() ||
+	  Loops[LoopCount - 1].TargetPkg() == D.ParentPkg())
+	 return true;
+   }
+   
+   Loops[LoopCount++] = D;
+   
+   // Mark the packages as being part of a loop.
+   //Flag(D.TargetPkg(),Loop);
+   //Flag(D.ParentPkg(),Loop);
+   /* This is currently disabled because the Loop flag is being used for
+      loop management in the package manager. Check the orderlist.h file for more info */
+   return true;
+}
+									/*}}}*/
+// OrderList::WipeFlags - Unset the given flags from all packages	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgOrderList::WipeFlags(unsigned long F)
+{
+   auto Size = Cache.Head().PackageCount;
+   for (decltype(Size) I = 0; I != Size; ++I)
+      Flags[I] &= ~F;
+}
+									/*}}}*/
+// OrderList::CheckDep - Check a dependency for truth			/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs a complete analysis of the dependency wrt to the
+   current add list. It returns true if after all events are
+   performed it is still true. This sort of routine can be approximated
+   by examining the DepCache, however in convoluted cases of provides
+   this fails to produce a suitable result. */
+bool pkgOrderList::CheckDep(DepIterator D)
+{
+   std::unique_ptr<Version *[]> List(D.AllTargets());
+   bool Hit = false;
+   for (Version **I = List.get(); *I != 0; I++)
+   {
+      VerIterator Ver(Cache,*I);
+      PkgIterator Pkg = Ver.ParentPkg();
+      
+      /* The meaning of Added and AddPending is subtle. AddPending is
+       	 an indication that the package is looping. Because of the
+       	 way ordering works Added means the package will be unpacked
+       	 before this one and AddPending means after. It is therefore
+       	 correct to ignore AddPending in all cases, but that exposes
+       	 reverse-ordering loops which should be ignored. */
+      if (IsFlag(Pkg,Added) == true ||
+	  (IsFlag(Pkg,AddPending) == true && D.Reverse() == true))
+      {
+	 if (Cache[Pkg].InstallVer != *I)
+	    continue;
+      }
+      else
+	 if ((Version *)Pkg.CurrentVer() != *I || 
+	     Pkg.State() != PkgIterator::NeedsNothing)
+	    continue;
+      
+      /* Conflicts requires that all versions are not present, depends
+         just needs one */
+      if (D.IsNegative() == false)
+      {
+      	 // ignore provides by older versions of this package
+	 if (((D.Reverse() == false && Pkg == D.ParentPkg()) ||
+	      (D.Reverse() == true && Pkg == D.TargetPkg())) &&
+	     Cache[Pkg].InstallVer != *I)
+	    continue;
+
+	 /* Try to find something that does not have the after flag set
+	    if at all possible */
+	 if (IsFlag(Pkg,After) == true)
+	 {
+	    Hit = true;
+	    continue;
+	 }
+      
+	 return true;
+      }
+      else
+      {
+	 if (IsFlag(Pkg,After) == true)
+	    Flag(D.ParentPkg(),After);
+	 
+	 return false;
+      }      
+   }
+
+   // We found a hit, but it had the after flag set
+   if (Hit == true && D->Type == pkgCache::Dep::PreDepends)
+   {
+      Flag(D.ParentPkg(),After);
+      return true;
+   }
+   
+   /* Conflicts requires that all versions are not present, depends
+      just needs one */
+   if (D->Type == pkgCache::Dep::Conflicts ||
+       D->Type == pkgCache::Dep::Obsoletes)
+      return true;
+   return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/orderlist.h b/apt-pkg/orderlist.h
new file mode 100644
index 0000000..559bf98
--- /dev/null
+++ b/apt-pkg/orderlist.h
@@ -0,0 +1,126 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Order List - Represents and Manipulates an ordered list of packages.
+   
+   A list of packages can be ordered by a number of conflicting criteria
+   each given a specific priority. Each package also has a set of flags
+   indicating some useful things about it that are derived in the 
+   course of sorting. The pkgPackageManager class uses this class for
+   all of it's installation ordering needs.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ORDERLIST_H
+#define PKGLIB_ORDERLIST_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <string>
+
+class pkgDepCache;
+class APT_PUBLIC pkgOrderList : protected pkgCache::Namespace
+{
+   void * const d;
+   protected:
+
+   pkgDepCache &Cache;   
+   typedef bool (pkgOrderList::*DepFunc)(DepIterator D);
+
+   // These are the currently selected ordering functions
+   DepFunc Primary;
+   DepFunc Secondary;
+   DepFunc RevDepends;
+   DepFunc Remove;
+
+   // State
+   Package **End;
+   Package **List;
+   Package **AfterEnd;
+   std::string *FileList;
+   DepIterator Loops[20];
+   int LoopCount;
+   int Depth;
+   unsigned short *Flags;
+   bool Debug;
+   
+   // Main visit function
+   bool VisitNode(PkgIterator Pkg, char const* from);
+   bool VisitDeps(DepFunc F,PkgIterator Pkg);
+   bool VisitRDeps(DepFunc F,PkgIterator Pkg);
+   bool VisitRProvides(DepFunc F,VerIterator Ver);
+   bool VisitProvides(DepIterator Pkg,bool Critical);
+   
+   // Dependency checking functions.
+   bool DepUnPackCrit(DepIterator D);
+   bool DepUnPackPreD(DepIterator D);
+   bool DepUnPackPre(DepIterator D);
+   bool DepUnPackDep(DepIterator D);
+   bool DepConfigure(DepIterator D);
+   bool DepRemove(DepIterator D);
+   
+   // Analysis helpers
+   bool AddLoop(DepIterator D);
+   bool CheckDep(DepIterator D);
+   bool DoRun();
+   
+   // For pre sorting
+   int OrderCompareA(Package *a, Package *b) APT_PURE;
+   int OrderCompareB(Package *a, Package *b) APT_PURE;
+   int FileCmp(PkgIterator A,PkgIterator B) APT_PURE;
+   
+   public:
+
+   typedef Package **iterator;
+   
+   /* State flags
+      The Loop flag can be set on a package that is currently being processed by either SmartConfigure or
+      SmartUnPack. This allows the package manager to tell when a loop has been formed as it will try to 
+      SmartUnPack or SmartConfigure a package with the Loop flag set. It will then either stop (as it knows
+      that the operation is unnecessary as its already in process), or in the case of the conflicts resolution
+      in SmartUnPack, use EarlyRemove to resolve the situation.  */
+   enum Flags {Added = (1 << 0), AddPending = (1 << 1),
+               Immediate = (1 << 2), Loop = (1 << 3),
+               UnPacked = (1 << 4), Configured = (1 << 5),
+               Removed = (1 << 6),        // Early Remove
+               InList = (1 << 7),
+               After = (1 << 8),
+               States = (UnPacked | Configured | Removed)};
+
+   // Flag manipulators
+   inline bool IsFlag(PkgIterator Pkg,unsigned long F) {return (Flags[Pkg->ID] & F) == F;};
+   inline bool IsFlag(Package *Pkg,unsigned long F) {return (Flags[Pkg->ID] & F) == F;};
+   void Flag(PkgIterator Pkg,unsigned long State, unsigned long F) {Flags[Pkg->ID] = (Flags[Pkg->ID] & (~F)) | State;};
+   inline void Flag(PkgIterator Pkg,unsigned long F) {Flags[Pkg->ID] |= F;};
+   inline void Flag(Package *Pkg,unsigned long F) {Flags[Pkg->ID] |= F;};
+   // RmFlag removes a flag from a package 
+   inline void RmFlag(Package *Pkg,unsigned long F) {Flags[Pkg->ID] &= ~F;};
+   // IsNow will return true if the Pkg has been not been either configured or unpacked
+   inline bool IsNow(PkgIterator Pkg) {return (Flags[Pkg->ID] & (States & (~Removed))) == 0;};
+   bool IsMissing(PkgIterator Pkg) APT_PURE;
+   void WipeFlags(unsigned long F);
+   void SetFileList(std::string *FileList) {this->FileList = FileList;};
+
+   // Accessors
+   inline iterator begin() {return List;};
+   inline iterator end() {return End;};
+   inline void push_back(Package *Pkg) {*(End++) = Pkg;};
+   inline void push_back(PkgIterator Pkg) {*(End++) = Pkg;};
+   inline void pop_back() {End--;};
+   inline bool empty() {return End == List;};
+   inline unsigned int size() {return End - List;};
+   
+   // Ordering modes
+   bool OrderCritical();
+   bool OrderUnpack(std::string *FileList = 0);
+   bool OrderConfigure();
+
+   int Score(PkgIterator Pkg);
+
+   explicit pkgOrderList(pkgDepCache *Cache);
+   virtual ~pkgOrderList();
+};
+
+#endif
diff --git a/apt-pkg/packagemanager.cc b/apt-pkg/packagemanager.cc
new file mode 100644
index 0000000..48dd03f
--- /dev/null
+++ b/apt-pkg/packagemanager.cc
@@ -0,0 +1,1172 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Package Manager - Abstracts the package manager
+
+   More work is needed in the area of transitioning provides, ie exim
+   replacing smail. This can cause interesting side effects.
+
+   Other cases involving conflicts+replaces should be tested. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/edsp.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/install-progress.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/orderlist.h>
+#include <apt-pkg/packagemanager.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/prettyprinters.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/version.h>
+
+#include <iostream>
+#include <list>
+#include <string>
+#include <stddef.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+bool pkgPackageManager::SigINTStop = false;
+
+// PM::PackageManager - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgPackageManager::pkgPackageManager(pkgDepCache *pCache) : Cache(*pCache),
+							    List(NULL), Res(Incomplete), d(NULL)
+{
+   FileNames = new string[Cache.Head().PackageCount];
+   Debug = _config->FindB("Debug::pkgPackageManager",false);
+   NoImmConfigure = !_config->FindB("APT::Immediate-Configure",true);
+   ImmConfigureAll = _config->FindB("APT::Immediate-Configure-All",false);
+}
+									/*}}}*/
+// PM::PackageManager - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgPackageManager::~pkgPackageManager()
+{
+   delete List;
+   delete [] FileNames;
+}
+									/*}}}*/
+// PM::GetArchives - Queue the archives for download			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgPackageManager::GetArchives(pkgAcquire *Owner,pkgSourceList *Sources,
+				    pkgRecords *Recs)
+{
+   if (CreateOrderList() == false)
+      return false;
+   
+   bool const ordering =
+	_config->FindB("PackageManager::UnpackAll",true) ?
+		List->OrderUnpack() : List->OrderCritical();
+   if (ordering == false)
+      return _error->Error("Internal ordering error");
+
+   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
+   {
+      PkgIterator Pkg(Cache,*I);
+      FileNames[Pkg->ID] = string();
+      
+      // Skip packages to erase
+      if (Cache[Pkg].Delete() == true)
+	 continue;
+
+      // Skip Packages that need configure only.
+      if (Pkg.State() == pkgCache::PkgIterator::NeedsConfigure && 
+	  Cache[Pkg].Keep() == true)
+	 continue;
+
+      // Skip already processed packages
+      if (List->IsNow(Pkg) == false)
+	 continue;
+
+      new pkgAcqArchive(Owner,Sources,Recs,Cache[Pkg].InstVerIter(Cache),
+			FileNames[Pkg->ID]);
+   }
+
+   return true;
+}
+									/*}}}*/
+// PM::FixMissing - Keep all missing packages				/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called to correct the installation when packages could not
+   be downloaded. */
+bool pkgPackageManager::FixMissing()
+{   
+   pkgDepCache::ActionGroup group(Cache);
+   pkgProblemResolver Resolve(&Cache);
+   List->SetFileList(FileNames);
+
+   bool Bad = false;
+   for (PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (List->IsMissing(I) == false)
+	 continue;
+   
+      // Okay, this file is missing and we need it. Mark it for keep 
+      Bad = true;
+      Cache.MarkKeep(I, false, false);
+   }
+ 
+   // We have to empty the list otherwise it will not have the new changes
+   delete List;
+   List = 0;
+   
+   if (Bad == false)
+      return true;
+   
+   // Now downgrade everything that is broken
+   return Resolve.ResolveByKeep() == true && Cache.BrokenCount() == 0;   
+}
+									/*}}}*/
+// PM::ImmediateAdd - Add the immediate flag recursively		/*{{{*/
+// ---------------------------------------------------------------------
+/* This adds the immediate flag to the pkg and recursively to the
+   dependencies
+ */
+void pkgPackageManager::ImmediateAdd(PkgIterator I, bool UseInstallVer, unsigned const int &Depth)
+{
+   DepIterator D;
+   
+   if(UseInstallVer)
+   {
+      if(Cache[I].InstallVer == 0)
+	 return;
+      D = Cache[I].InstVerIter(Cache).DependsList(); 
+   } else {
+      if (I->CurrentVer == 0)
+	 return;
+      D = I.CurrentVer().DependsList(); 
+   }
+
+   for ( /* nothing */  ; D.end() == false; ++D)
+      if (D->Type == pkgCache::Dep::Depends || D->Type == pkgCache::Dep::PreDepends)
+      {
+	 if(!List->IsFlag(D.TargetPkg(), pkgOrderList::Immediate))
+	 {
+	    if(Debug)
+	       clog << OutputInDepth(Depth) << "ImmediateAdd(): Adding Immediate flag to " << APT::PrettyPkg(&Cache, D.TargetPkg()) << " cause of " << D.DepType() << " " << I.FullName() << endl;
+	    List->Flag(D.TargetPkg(),pkgOrderList::Immediate);
+	    ImmediateAdd(D.TargetPkg(), UseInstallVer, Depth + 1);
+	 }
+      }
+   return;
+}
+									/*}}}*/
+// PM::CreateOrderList - Create the ordering class			/*{{{*/
+// ---------------------------------------------------------------------
+/* This populates the ordering list with all the packages that are
+   going to change. */
+bool pkgPackageManager::CreateOrderList()
+{
+   if (List != 0)
+      return true;
+   
+   delete List;
+   List = new pkgOrderList(&Cache);
+
+   if (Debug && ImmConfigureAll) 
+      clog << "CreateOrderList(): Adding Immediate flag for all packages because of APT::Immediate-Configure-All" << endl;
+   
+   // Generate the list of affected packages and sort it
+   for (PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      // Ignore no-version packages
+      if (I->VersionList == 0)
+	 continue;
+      
+      // Mark the package and its dependents for immediate configuration
+      if ((((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential) &&
+	  NoImmConfigure == false) || ImmConfigureAll)
+      {
+	 if(Debug && !ImmConfigureAll)
+	    clog << "CreateOrderList(): Adding Immediate flag for " << I.FullName() << endl;
+	 List->Flag(I,pkgOrderList::Immediate);
+	 
+	 if (!ImmConfigureAll) {
+	    // Look for other install packages to make immediate configurea
+	    ImmediateAdd(I, true);
+	  
+	    // And again with the current version.
+	    ImmediateAdd(I, false);
+	 }
+      }
+      
+      // Not interesting
+      if ((Cache[I].Keep() == true || 
+	  Cache[I].InstVerIter(Cache) == I.CurrentVer()) && 
+	  I.State() == pkgCache::PkgIterator::NeedsNothing &&
+	  (Cache[I].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall &&
+	  (I.Purge() != false || Cache[I].Mode != pkgDepCache::ModeDelete ||
+	   (Cache[I].iFlags & pkgDepCache::Purge) != pkgDepCache::Purge))
+	 continue;
+      
+      // Append it to the list
+      List->push_back(I);      
+   }
+   
+   return true;
+}
+									/*}}}*/
+// PM::DepAlwaysTrue - Returns true if this dep is irrelevant		/*{{{*/
+// ---------------------------------------------------------------------
+/* The restriction on provides is to eliminate the case when provides
+   are transitioning between valid states [ie exim to smail] */
+bool pkgPackageManager::DepAlwaysTrue(DepIterator D)
+{
+   if (D.TargetPkg()->ProvidesList != 0)
+      return false;
+   
+   if ((Cache[D] & pkgDepCache::DepInstall) != 0 &&
+       (Cache[D] & pkgDepCache::DepNow) != 0)
+      return true;
+   return false;
+}
+									/*}}}*/
+// PM::CheckRConflicts - Look for reverse conflicts			/*{{{*/
+// ---------------------------------------------------------------------
+/* This looks over the reverses for a conflicts line that needs early
+   removal. */
+bool pkgPackageManager::CheckRConflicts(PkgIterator Pkg,DepIterator D,
+					const char *Ver)
+{
+   for (;D.end() == false; ++D)
+   {
+      if (D->Type != pkgCache::Dep::Conflicts &&
+	  D->Type != pkgCache::Dep::Obsoletes)
+	 continue;
+
+      // The package hasn't been changed
+      if (List->IsNow(Pkg) == false)
+	 continue;
+      
+      // Ignore self conflicts, ignore conflicts from irrelevant versions
+      if (D.IsIgnorable(Pkg) || D.ParentVer() != D.ParentPkg().CurrentVer())
+	 continue;
+      
+      if (Cache.VS().CheckDep(Ver,D->CompareOp,D.TargetVer()) == false)
+	 continue;
+
+      if (EarlyRemove(D.ParentPkg(), &D) == false)
+	 return _error->Error("Reverse conflicts early remove for package '%s' failed",
+			      Pkg.FullName().c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// PM::CheckRBreaks - Look for reverse breaks				/*{{{*/
+bool pkgPackageManager::CheckRBreaks(PkgIterator const &Pkg, DepIterator D,
+				     const char * const Ver)
+{
+   for (;D.end() == false; ++D)
+   {
+      if (D->Type != pkgCache::Dep::DpkgBreaks)
+	 continue;
+
+      PkgIterator const DP = D.ParentPkg();
+      if (Cache[DP].Delete() == false)
+	 continue;
+
+      // Ignore self conflicts, ignore conflicts from irrelevant versions
+      if (D.IsIgnorable(Pkg) || D.ParentVer() != DP.CurrentVer())
+	 continue;
+
+      if (Cache.VS().CheckDep(Ver, D->CompareOp, D.TargetVer()) == false)
+	 continue;
+
+      // no earlyremove() here as user has already agreed to the permanent removal
+      if (SmartRemove(DP) == false)
+	 return _error->Error("Internal Error, Could not early remove %s (%d)",DP.FullName().c_str(), 4);
+   }
+   return true;
+}
+									/*}}}*/
+// PM::ConfigureAll - Run the all out configuration			/*{{{*/
+// ---------------------------------------------------------------------
+/* This configures every package. It is assumed they are all unpacked and
+   that the final configuration is valid. This is also used to catch packages
+   that have not been configured when using ImmConfigureAll */
+bool pkgPackageManager::ConfigureAll()
+{
+   pkgOrderList OList(&Cache);
+   
+   // Populate the order list
+   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
+      if (List->IsFlag(pkgCache::PkgIterator(Cache,*I),
+		       pkgOrderList::UnPacked) == true)
+	 OList.push_back(*I);
+   
+   if (OList.OrderConfigure() == false)
+      return false;
+
+   std::string const conf = _config->Find("PackageManager::Configure", "smart");
+   bool const ConfigurePkgs = (ImmConfigureAll || conf == "all");
+
+   // Perform the configuring
+   for (pkgOrderList::iterator I = OList.begin(); I != OList.end(); ++I)
+   {
+      PkgIterator Pkg(Cache,*I);
+      
+      /* Check if the package has been configured, this can happen if SmartConfigure
+         calls its self */ 
+      if (List->IsFlag(Pkg,pkgOrderList::Configured)) continue;
+
+      if (ConfigurePkgs == true && SmartConfigure(Pkg, 0) == false) {
+         if (ImmConfigureAll)
+            _error->Error(_("Could not perform immediate configuration on '%s'. "
+			"Please see man 5 apt.conf under APT::Immediate-Configure for details. (%d)"),Pkg.FullName().c_str(),1);
+         else
+            _error->Error("Internal error, packages left unconfigured. %s",Pkg.FullName().c_str());
+	 return false;
+      }
+      
+      List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);
+   }
+   
+   return true;
+}
+									/*}}}*/
+// PM::NonLoopingSmart - helper to avoid loops while calling Smart methods /*{{{*/
+// -----------------------------------------------------------------------
+/* ensures that a loop of the form A depends B, B depends A (and similar)
+   is not leading us down into infinite recursion segfault land */
+bool pkgPackageManager::NonLoopingSmart(SmartAction const action, pkgCache::PkgIterator &Pkg,
+      pkgCache::PkgIterator DepPkg, int const Depth, bool const PkgLoop,
+      bool * const Bad, bool * const Changed)
+{
+   if (PkgLoop == false)
+      List->Flag(Pkg,pkgOrderList::Loop);
+   bool success = false;
+   switch(action)
+   {
+      case UNPACK_IMMEDIATE: success = SmartUnPack(DepPkg, true, Depth + 1); break;
+      case UNPACK: success = SmartUnPack(DepPkg, false, Depth + 1); break;
+      case CONFIGURE: success = SmartConfigure(DepPkg, Depth + 1); break;
+   }
+   if (PkgLoop == false)
+      List->RmFlag(Pkg,pkgOrderList::Loop);
+
+   if (success == false)
+      return false;
+
+   if (Bad != NULL)
+      *Bad = false;
+   if (Changed != NULL && List->IsFlag(DepPkg,pkgOrderList::Loop) == false)
+      *Changed = true;
+   return true;
+}
+									/*}}}*/
+// PM::SmartConfigure - Perform immediate configuration of the pkg	/*{{{*/
+// ---------------------------------------------------------------------
+/* This function tries to put the system in a state where Pkg can be configured.
+   This involves checking each of Pkg's dependencies and unpacking and
+   configuring packages where needed. */
+bool pkgPackageManager::SmartConfigure(PkgIterator Pkg, int const Depth)
+{
+   // If this is true, only check and correct and dependencies without the Loop flag
+   bool const PkgLoop = List->IsFlag(Pkg,pkgOrderList::Loop);
+
+   if (Debug) {
+      VerIterator InstallVer = VerIterator(Cache,Cache[Pkg].InstallVer);
+      clog << OutputInDepth(Depth) << "SmartConfigure " << Pkg.FullName() << " (" << InstallVer.VerStr() << ")";
+      if (PkgLoop)
+        clog << " (Only Correct Dependencies)";
+      clog << endl;
+   }
+
+   VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);
+
+   /* Because of the ordered list, most dependencies should be unpacked,
+      however if there is a loop (A depends on B, B depends on A) this will not
+      be the case, so check for dependencies before configuring. */
+   bool Bad = false, Changed = false;
+   const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 5000);
+   unsigned int i=0;
+   std::list<DepIterator> needConfigure;
+   do
+   {
+      // Check each dependency and see if anything needs to be done
+      // so that it can be configured
+      Changed = false;
+      for (DepIterator D = instVer.DependsList(); D.end() == false; )
+      {
+	 // Compute a single dependency element (glob or)
+	 pkgCache::DepIterator Start, End;
+	 D.GlobOr(Start,End);
+
+	 if (End->Type != pkgCache::Dep::Depends && End->Type != pkgCache::Dep::PreDepends)
+	    continue;
+	 Bad = true;
+
+         // the first pass checks if we its all good, i.e. if we have
+         // to do anything at all
+	 for (DepIterator Cur = Start; true; ++Cur)
+	 {
+	    std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+
+	    for (Version **I = VList.get(); *I != 0; ++I)
+	    {
+	       VerIterator Ver(Cache,*I);
+	       PkgIterator DepPkg = Ver.ParentPkg();
+
+	       // Check if the current version of the package is available and will satisfy this dependency
+	       if (DepPkg.CurrentVer() == Ver && List->IsNow(DepPkg) == true &&
+		   List->IsFlag(DepPkg,pkgOrderList::Removed) == false &&
+		   DepPkg.State() == PkgIterator::NeedsNothing &&
+		   (Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+	       {
+		  Bad = false;
+		  break;
+	       }
+
+	       // Check if the version that is going to be installed will satisfy the dependency
+	       if (Cache[DepPkg].InstallVer != *I || List->IsNow(DepPkg) == false)
+		  continue;
+
+	       if (PkgLoop == true)
+	       {
+		  if (Debug)
+		     std::clog << OutputInDepth(Depth) << "Package " << APT::PrettyPkg(&Cache, Pkg) << " loops in SmartConfigure";
+		  if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
+		     Bad = false;
+		  else if (Debug)
+		     std::clog << ", but it isn't unpacked yet";
+		  if (Debug)
+		     std::clog << std::endl;
+	       }
+	    }
+
+            if (Cur == End || Bad == false)
+	       break;
+         }
+
+         // this dependency is in a good state, so we can stop
+         if (Bad == false)
+         {
+            if (Debug)
+               std::clog << OutputInDepth(Depth) << "Found ok dep " << APT::PrettyPkg(&Cache, Start.TargetPkg()) << std::endl;
+            continue;
+         }
+
+	 // Check for dependencies that have not been unpacked, 
+         // probably due to loops.
+	 for (DepIterator Cur = Start; true; ++Cur)
+	 {
+	    std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+
+	    for (Version **I = VList.get(); *I != 0; ++I)
+	    {
+	       VerIterator Ver(Cache,*I);
+	       PkgIterator DepPkg = Ver.ParentPkg();
+
+	       // Check if the current version of the package is available and will satisfy this dependency
+	       if (DepPkg.CurrentVer() == Ver && List->IsNow(DepPkg) == true &&
+		   List->IsFlag(DepPkg,pkgOrderList::Removed) == false &&
+		   DepPkg.State() == PkgIterator::NeedsNothing &&
+		   (Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+                  continue;
+
+	       // Check if the version that is going to be installed will satisfy the dependency
+	       if (Cache[DepPkg].InstallVer != *I || List->IsNow(DepPkg) == false)
+		  continue;
+
+	       if (PkgLoop == true)
+	       {
+		  if (Debug)
+		     std::clog << OutputInDepth(Depth) << "Package " << APT::PrettyPkg(&Cache, Pkg) << " loops in SmartConfigure";
+		  if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
+		     Bad = false;
+		  else if (Debug)
+		     std::clog << ", but it isn't unpacked yet";
+		  if (Debug)
+		     std::clog << std::endl;
+	       }
+	       else
+	       {
+		  if (Debug)
+		     clog << OutputInDepth(Depth) << "Unpacking " << DepPkg.FullName() << " to avoid loop " << APT::PrettyDep(&Cache, Cur) << endl;
+		  if (NonLoopingSmart(UNPACK_IMMEDIATE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+		     return false;
+	       }
+               // at this point we either unpacked a Dep or we are in a loop,
+               // no need to unpack a second one
+	       break;
+	    }
+
+	    if (Cur == End || Bad == false)
+	       break;
+	 }
+
+	 if (Bad == false)
+	    continue;
+
+	 needConfigure.push_back(Start);
+      }
+      if (i++ > max_loops)
+         return _error->Error("Internal error: MaxLoopCount reached in SmartUnPack (1) for %s, aborting", Pkg.FullName().c_str());
+   } while (Changed == true);
+
+   // now go over anything that needs configuring
+   Bad = false, Changed = false, i = 0;
+   do
+   {
+      Changed = false;
+      for (std::list<DepIterator>::const_iterator D = needConfigure.begin(); D != needConfigure.end(); ++D)
+      {
+	 // Compute a single dependency element (glob or) without modifying D
+	 pkgCache::DepIterator Start, End;
+	 {
+	    pkgCache::DepIterator Discard = *D;
+	    Discard.GlobOr(Start,End);
+	 }
+
+	 if (End->Type != pkgCache::Dep::Depends && End->Type != pkgCache::Dep::PreDepends)
+	    continue;
+	 Bad = true;
+
+	 // Search for dependencies which are unpacked but aren't configured yet (maybe loops)
+	 for (DepIterator Cur = Start; true; ++Cur)
+	 {
+	    std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+
+	    for (Version **I = VList.get(); *I != 0; ++I)
+	    {
+	       VerIterator Ver(Cache,*I);
+	       PkgIterator DepPkg = Ver.ParentPkg();
+
+	       // Check if the version that is going to be installed will satisfy the dependency
+	       if (Cache[DepPkg].InstallVer != *I)
+		  continue;
+
+	       if (List->IsFlag(DepPkg,pkgOrderList::UnPacked))
+	       {
+		  if (List->IsFlag(DepPkg,pkgOrderList::Loop) && PkgLoop)
+		  {
+		    // This dependency has already been dealt with by another SmartConfigure on Pkg
+		    Bad = false;
+		    break;
+		  }
+		  if (Debug)
+		     std::clog << OutputInDepth(Depth) << "Configure already unpacked " << APT::PrettyPkg(&Cache, DepPkg) << std::endl;
+		  if (NonLoopingSmart(CONFIGURE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+		     return false;
+		  break;
+
+	       }
+	       else if (List->IsFlag(DepPkg,pkgOrderList::Configured))
+	       {
+		  Bad = false;
+		  break;
+	       }
+	    }
+	    if (Cur == End || Bad == false)
+	       break;
+         }
+
+
+	 if (Bad == true && Changed == false && Debug == true)
+	    std::clog << OutputInDepth(Depth) << "Could not satisfy " << APT::PrettyDep(&Cache, *D) << std::endl;
+      }
+      if (i++ > max_loops)
+         return _error->Error("Internal error: MaxLoopCount reached in SmartUnPack (2) for %s, aborting", Pkg.FullName().c_str());
+   } while (Changed == true);
+
+   if (Bad == true)
+      return _error->Error(_("Could not configure '%s'. "),Pkg.FullName().c_str());
+
+   // Check for reverse conflicts.
+   if (CheckRBreaks(Pkg,Pkg.RevDependsList(), instVer.VerStr()) == false)
+      return false;
+
+   for (PrvIterator P = instVer.ProvidesList(); P.end() == false; ++P)
+      if (Pkg->Group != P.OwnerPkg()->Group)
+	 CheckRBreaks(Pkg,P.ParentPkg().RevDependsList(),P.ProvideVersion());
+
+   if (PkgLoop) return true;
+
+   static std::string const conf = _config->Find("PackageManager::Configure", "smart");
+   static bool const ConfigurePkgs = (conf == "all" || conf == "smart");
+
+   if (List->IsFlag(Pkg,pkgOrderList::Configured))
+      return _error->Error("Internal configure error on '%s'.", Pkg.FullName().c_str());
+
+   if (ConfigurePkgs == true && Configure(Pkg) == false)
+      return false;
+
+   List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);
+
+   if ((Cache[Pkg].InstVerIter(Cache)->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same &&
+       not List->IsFlag(Pkg, pkgOrderList::Immediate))
+      for (PkgIterator P = Pkg.Group().PackageList();
+	   P.end() == false; P = Pkg.Group().NextPkg(P))
+      {
+	 if (Pkg == P || List->IsFlag(P,pkgOrderList::Configured) == true ||
+	     List->IsFlag(P,pkgOrderList::UnPacked) == false ||
+	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
+	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
+	    continue;
+	 if (SmartConfigure(P, (Depth +1)) == false)
+	    return false;
+      }
+
+   // Sanity Check
+   if (List->IsFlag(Pkg,pkgOrderList::Configured) == false)
+      return _error->Error(_("Could not configure '%s'. "),Pkg.FullName().c_str());
+
+   return true;
+}
+									/*}}}*/
+// PM::EarlyRemove - Perform removal of packages before their time	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is called to deal with conflicts arising from unpacking */
+bool pkgPackageManager::EarlyRemove(PkgIterator Pkg, DepIterator const * const Dep)
+{
+   if (List->IsNow(Pkg) == false)
+      return true;
+
+   // Already removed it
+   if (List->IsFlag(Pkg,pkgOrderList::Removed) == true)
+      return true;
+
+   // Woops, it will not be re-installed!
+   if (List->IsFlag(Pkg,pkgOrderList::InList) == false)
+      return false;
+
+   // these breaks on M-A:same packages can be dealt with. They 'loop' by design
+   if (Dep != NULL && (*Dep)->Type == pkgCache::Dep::DpkgBreaks && Dep->IsMultiArchImplicit() == true)
+      return true;
+
+   // Essential packages get special treatment
+   bool IsEssential = false;
+   if ((Pkg->Flags & pkgCache::Flag::Essential) != 0)
+      IsEssential = true;
+   bool IsProtected = false;
+   if ((Pkg->Flags & pkgCache::Flag::Important) != 0)
+      IsProtected = true;
+
+   /* Check for packages that are the dependents of essential packages and
+      promote them too */
+   if (Pkg->CurrentVer != 0)
+   {
+      for (pkgCache::DepIterator D = Pkg.RevDependsList(); D.end() == false &&
+	   IsEssential == false; ++D)
+	 if (D->Type == pkgCache::Dep::Depends || D->Type == pkgCache::Dep::PreDepends) {
+	    if ((D.ParentPkg()->Flags & pkgCache::Flag::Essential) != 0)
+	       IsEssential = true;
+	    if ((D.ParentPkg()->Flags & pkgCache::Flag::Important) != 0)
+	       IsProtected = true;
+	 }
+   }
+
+   // dpkg will auto-deconfigure it, no need for the big remove hammer
+   if (Dep != NULL && (*Dep)->Type == pkgCache::Dep::DpkgBreaks)
+      return true;
+   else if (IsEssential == true)
+   {
+      // FIXME: Unify messaging with Protected below.
+      if (_config->FindB("APT::Force-LoopBreak",false) == false)
+	 return _error->Error(_("This installation run will require temporarily "
+				"removing the essential package %s due to a "
+				"Conflicts/Pre-Depends loop. This is often bad, "
+				"but if you really want to do it, activate the "
+				"APT::Force-LoopBreak option."),Pkg.FullName().c_str());
+   }
+   else if (IsProtected == true)
+   {
+      // FIXME: Message should talk about Protected, not Essential, and unified.
+      if (_config->FindB("APT::Force-LoopBreak",false) == false)
+	 return _error->Error(_("This installation run will require temporarily "
+				"removing the essential package %s due to a "
+				"Conflicts/Pre-Depends loop. This is often bad, "
+				"but if you really want to do it, activate the "
+				"APT::Force-LoopBreak option."),Pkg.FullName().c_str());
+   }
+
+   bool Res = SmartRemove(Pkg);
+   if (Cache[Pkg].Delete() == false)
+      List->Flag(Pkg,pkgOrderList::Removed,pkgOrderList::States);
+
+   return Res;
+}
+									/*}}}*/
+// PM::SmartRemove - Removal Helper					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgPackageManager::SmartRemove(PkgIterator Pkg)
+{
+   if (List->IsNow(Pkg) == false)
+      return true;
+
+   List->Flag(Pkg,pkgOrderList::Configured,pkgOrderList::States);
+
+   return Remove(Pkg,(Cache[Pkg].iFlags & pkgDepCache::Purge) == pkgDepCache::Purge);
+}
+									/*}}}*/
+// PM::SmartUnPack - Install helper					/*{{{*/
+// ---------------------------------------------------------------------
+/* This puts the system in a state where it can Unpack Pkg, if Pkg is already
+   unpacked, or when it has been unpacked, if Immediate==true it configures it. */
+bool pkgPackageManager::SmartUnPack(PkgIterator Pkg, bool const Immediate, int const Depth)
+{
+   bool PkgLoop = List->IsFlag(Pkg,pkgOrderList::Loop);
+
+   if (Debug) {
+      clog << OutputInDepth(Depth) << "SmartUnPack " << Pkg.FullName();
+      VerIterator InstallVer = VerIterator(Cache,Cache[Pkg].InstallVer);
+      if (Pkg.CurrentVer() == 0)
+        clog << " (install version " << InstallVer.VerStr() << ")";
+      else
+        clog << " (replace version " << Pkg.CurrentVer().VerStr() << " with " << InstallVer.VerStr() << ")";
+      if (PkgLoop)
+        clog << " (Only Perform PreUnpack Checks)";
+      if (Immediate)
+	 clog << " immediately";
+      clog << endl;
+   }
+
+   VerIterator const instVer = Cache[Pkg].InstVerIter(Cache);
+
+   /* PreUnpack Checks: This loop checks and attempts to rectify any problems that would prevent the package being unpacked.
+      It addresses: PreDepends, Conflicts, Obsoletes and Breaks (DpkgBreaks). Any resolutions that do not require it should
+      avoid configuration (calling SmartUnpack with Immediate=true), this is because when unpacking some packages with
+      complex dependency structures, trying to configure some packages while breaking the loops can complicate things.
+      This will be either dealt with if the package is configured as a dependency of Pkg (if and when Pkg is configured),
+      or by the ConfigureAll call at the end of the for loop in OrderInstall. */
+   bool SomethingBad = false, Changed = false;
+   bool couldBeTemporaryRemoved = Depth != 0 && List->IsFlag(Pkg,pkgOrderList::Removed) == false;
+   const unsigned int max_loops = _config->FindI("APT::pkgPackageManager::MaxLoopCount", 5000);
+   unsigned int i = 0;
+   do 
+   {
+      Changed = false;
+      for (DepIterator D = instVer.DependsList(); D.end() == false; )
+      {
+	 // Compute a single dependency element (glob or)
+	 pkgCache::DepIterator Start, End;
+	 D.GlobOr(Start,End);
+
+	 if (End->Type == pkgCache::Dep::PreDepends)
+         {
+	    bool Bad = true;
+	    if (Debug)
+	       clog << OutputInDepth(Depth) << "PreDepends order for " << Pkg.FullName() << std::endl;
+
+	    // Look for easy targets: packages that are already okay
+	    for (DepIterator Cur = Start; Bad == true; ++Cur)
+	    {
+	       std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+	       for (Version **I = VList.get(); *I != 0; ++I)
+	       {
+		  VerIterator Ver(Cache,*I);
+		  PkgIterator Pkg = Ver.ParentPkg();
+
+		  // See if the current version is ok
+		  if (Pkg.CurrentVer() == Ver && List->IsNow(Pkg) == true &&
+		      Pkg.State() == PkgIterator::NeedsNothing &&
+		      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+		  {
+		     Bad = false;
+		     if (Debug)
+			clog << OutputInDepth(Depth) << "Found ok package " << Pkg.FullName() << endl;
+		     break;
+		  }
+	       }
+	       if (Cur == End)
+		  break;
+	    }
+
+	    // Look for something that could be configured.
+	    for (DepIterator Cur = Start; Bad == true && Cur.end() == false; ++Cur)
+	    {
+	       std::unique_ptr<Version *[]> VList(Cur.AllTargets());
+	       for (Version **I = VList.get(); *I != 0; ++I)
+	       {
+		  VerIterator Ver(Cache,*I);
+		  PkgIterator DepPkg = Ver.ParentPkg();
+
+		  // Not the install version
+		  if (Cache[DepPkg].InstallVer != *I)
+		     continue;
+
+		  if (Cache[DepPkg].Keep() == true && DepPkg.State() == PkgIterator::NeedsNothing &&
+			(Cache[DepPkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+		     continue;
+
+		  if (List->IsFlag(DepPkg,pkgOrderList::Configured))
+		  {
+		     Bad = false;
+		     break;
+		  }
+
+		  // check if it needs unpack or if configure is enough
+		  if (List->IsFlag(DepPkg,pkgOrderList::UnPacked) == false)
+		  {
+		     // two packages pre-depending on each other can't be handled sanely
+		     if (List->IsFlag(DepPkg,pkgOrderList::Loop) && PkgLoop)
+		     {
+			// this isn't an error as there is potential for something else to satisfy it
+			// (like a provides or an or-group member)
+			if (Debug)
+			   clog << OutputInDepth(Depth) << "Unpack loop detected between " << DepPkg.FullName() << " and " << Pkg.FullName() << endl;
+			continue;
+		     }
+
+		     if (Debug)
+			clog << OutputInDepth(Depth) << "Trying to SmartUnpack " << DepPkg.FullName() << endl;
+		     if (NonLoopingSmart(UNPACK_IMMEDIATE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+			return false;
+		  }
+		  else
+		  {
+		     if (Debug)
+			clog << OutputInDepth(Depth) << "Trying to SmartConfigure " << DepPkg.FullName() << endl;
+		     if (NonLoopingSmart(CONFIGURE, Pkg, DepPkg, Depth, PkgLoop, &Bad, &Changed) == false)
+			return false;
+		  }
+		  break;
+	       }
+	    }
+
+	    if (Bad == true)
+	       SomethingBad = true;
+	 }
+	 else if (End->Type == pkgCache::Dep::Conflicts ||
+		  End->Type == pkgCache::Dep::Obsoletes ||
+		  End->Type == pkgCache::Dep::DpkgBreaks)
+	 {
+	    std::unique_ptr<Version *[]> VList(End.AllTargets());
+	    for (Version **I = VList.get(); *I != 0; ++I)
+	    {
+	       VerIterator Ver(Cache,*I);
+	       PkgIterator ConflictPkg = Ver.ParentPkg();
+	       if (ConflictPkg.CurrentVer() != Ver)
+	       {
+		  if (Debug)
+		     std::clog << OutputInDepth(Depth) << "Ignore not-installed version " << Ver.VerStr() << " of " << ConflictPkg.FullName() << " for " << APT::PrettyDep(&Cache, End) << std::endl;
+		  continue;
+	       }
+
+	       if (List->IsNow(ConflictPkg) == false)
+	       {
+		  if (Debug)
+		     std::clog << OutputInDepth(Depth) << "Ignore already dealt-with version " << Ver.VerStr() << " of " << ConflictPkg.FullName() << " for " << APT::PrettyDep(&Cache, End) << std::endl;
+		  continue;
+	       }
+
+	       if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == true)
+	       {
+		  if (Debug)
+		     clog << OutputInDepth(Depth) << "Ignoring " << APT::PrettyDep(&Cache, End) << " as " << ConflictPkg.FullName() << "was temporarily removed" << endl;
+		  continue;
+	       }
+
+	       if (List->IsFlag(ConflictPkg,pkgOrderList::Loop) && PkgLoop)
+	       {
+		  if (End->Type == pkgCache::Dep::DpkgBreaks && End.IsMultiArchImplicit() == true)
+		  {
+		     if (Debug)
+			clog << OutputInDepth(Depth) << "Because dependency is MultiArchImplicit we ignored looping on: " << APT::PrettyPkg(&Cache, ConflictPkg) << endl;
+		     continue;
+		  }
+		  if (Debug)
+		  {
+		     if (End->Type == pkgCache::Dep::DpkgBreaks)
+			clog << OutputInDepth(Depth) << "Because of breaks knot, deconfigure " << ConflictPkg.FullName() << " temporarily" << endl;
+		     else
+			clog << OutputInDepth(Depth) << "Because of conflict knot, removing " << ConflictPkg.FullName() << " temporarily" << endl;
+		  }
+		  if (EarlyRemove(ConflictPkg, &End) == false)
+		     return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 3);
+		  SomethingBad = true;
+		  continue;
+	       }
+
+	       if (Cache[ConflictPkg].Delete() == false)
+	       {
+		  if (Debug)
+		  {
+		     clog << OutputInDepth(Depth) << "Unpacking " << ConflictPkg.FullName() << " to avoid " << APT::PrettyDep(&Cache, End);
+		     if (PkgLoop == true)
+			clog << " (Looping)";
+		     clog << std::endl;
+		  }
+		  // we would like to avoid temporary removals and all that at best via a simple unpack
+		  _error->PushToStack();
+		  if (NonLoopingSmart(UNPACK, Pkg, ConflictPkg, Depth, PkgLoop, NULL, &Changed) == false)
+		  {
+		     // but if it fails ignore this failure and look for alternative ways of solving
+		     if (Debug)
+		     {
+			clog << OutputInDepth(Depth) << "Avoidance unpack of " << ConflictPkg.FullName() << " failed for " << APT::PrettyDep(&Cache, End) << " ignoring:" << std::endl;
+			_error->DumpErrors(std::clog, GlobalError::DEBUG, false);
+		     }
+		     _error->RevertToStack();
+		     // ignorance can only happen if a) one of the offenders is already gone
+		     if (List->IsFlag(ConflictPkg,pkgOrderList::Removed) == true)
+		     {
+			if (Debug)
+			   clog << OutputInDepth(Depth) << "But " << ConflictPkg.FullName() << " was temporarily removed in the meantime to satisfy " << APT::PrettyDep(&Cache, End) << endl;
+		     }
+		     else if (List->IsFlag(Pkg,pkgOrderList::Removed) == true)
+		     {
+			if (Debug)
+			   clog << OutputInDepth(Depth) << "But " << Pkg.FullName() << " was temporarily removed in the meantime to satisfy " <<  APT::PrettyDep(&Cache, End) << endl;
+		     }
+		     // or b) we can make one go (removal or dpkg auto-deconfigure)
+		     else
+		     {
+			if (Debug)
+			   clog << OutputInDepth(Depth) << "So temporary remove/deconfigure " << ConflictPkg.FullName() << " to satisfy " <<  APT::PrettyDep(&Cache, End) << endl;
+			if (EarlyRemove(ConflictPkg, &End) == false)
+			   return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 2);
+		     }
+		  }
+		  else
+		     _error->MergeWithStack();
+	       }
+	       else
+	       {
+		  if (Debug)
+		     clog << OutputInDepth(Depth) << "Removing " << ConflictPkg.FullName() << " now to avoid " << APT::PrettyDep(&Cache, End) << endl;
+		  // no earlyremove() here as user has already agreed to the permanent removal
+		  if (SmartRemove(ConflictPkg) == false)
+		     return _error->Error("Internal Error, Could not early remove %s (%d)",ConflictPkg.FullName().c_str(), 1);
+	       }
+	    }
+	 }
+      }
+      if (i++ > max_loops)
+         return _error->Error("Internal error: APT::pkgPackageManager::MaxLoopCount reached in SmartConfigure for %s, aborting", Pkg.FullName().c_str());
+   } while (Changed == true);
+
+   if (SomethingBad == true)
+      return _error->Error("Couldn't configure %s, probably a dependency cycle.", Pkg.FullName().c_str());
+
+   if (couldBeTemporaryRemoved == true && List->IsFlag(Pkg,pkgOrderList::Removed) == true)
+   {
+      if (Debug)
+	 std::clog << OutputInDepth(Depth) << "Prevent unpack as " << APT::PrettyPkg(&Cache, Pkg) << " is currently temporarily removed" << std::endl;
+      return true;
+   }
+
+   // Check for reverse conflicts.
+   if (CheckRConflicts(Pkg,Pkg.RevDependsList(),
+		   instVer.VerStr()) == false)
+		          return false;
+   
+   for (PrvIterator P = instVer.ProvidesList();
+	P.end() == false; ++P)
+      if (Pkg->Group != P.OwnerPkg()->Group)
+	 CheckRConflicts(Pkg,P.ParentPkg().RevDependsList(),P.ProvideVersion());
+
+   if (PkgLoop)
+      return true;
+
+   List->Flag(Pkg,pkgOrderList::UnPacked,pkgOrderList::States);
+
+   if (Immediate == true && (instVer->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+   {
+      /* Do lockstep M-A:same unpacking in two phases:
+	 First unpack all installed architectures, then the not installed.
+	 This way we avoid that M-A: enabled packages are installed before
+	 their older non-M-A enabled packages are replaced by newer versions */
+      bool const installed = Pkg->CurrentVer != 0;
+      if (installed == true &&
+	  (instVer != Pkg.CurrentVer() ||
+	   ((Cache[Pkg].iFlags & pkgDepCache::ReInstall) == pkgDepCache::ReInstall)) &&
+	  Install(Pkg,FileNames[Pkg->ID]) == false)
+	 return false;
+      for (PkgIterator P = Pkg.Group().PackageList();
+	   P.end() == false; P = Pkg.Group().NextPkg(P))
+      {
+	 if (P->CurrentVer == 0 || P == Pkg || List->IsFlag(P,pkgOrderList::UnPacked) == true ||
+	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
+	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
+	    continue;
+	 if (SmartUnPack(P, false, Depth + 1) == false)
+	    return false;
+      }
+      if (installed == false && Install(Pkg,FileNames[Pkg->ID]) == false)
+	 return false;
+      for (PkgIterator P = Pkg.Group().PackageList();
+	   P.end() == false; P = Pkg.Group().NextPkg(P))
+      {
+	 if (P->CurrentVer != 0 || P == Pkg || List->IsFlag(P,pkgOrderList::UnPacked) == true ||
+	     List->IsFlag(P,pkgOrderList::Configured) == true ||
+	     Cache[P].InstallVer == 0 || (P.CurrentVer() == Cache[P].InstallVer &&
+	      (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall))
+	    continue;
+	 if (SmartUnPack(P, false, Depth + 1) == false)
+	    return false;
+      }
+   }
+   // packages which are already unpacked don't need to be unpacked again
+   else if ((instVer != Pkg.CurrentVer() ||
+	     ((Cache[Pkg].iFlags & pkgDepCache::ReInstall) == pkgDepCache::ReInstall)) &&
+	    Install(Pkg,FileNames[Pkg->ID]) == false)
+      return false;
+
+   if (Immediate == true) {
+      // Perform immediate configuration of the package.
+      _error->PushToStack();
+      bool configured = SmartConfigure(Pkg, Depth + 1);
+      _error->RevertToStack();
+
+      if (not configured && Debug) {
+	 clog << OutputInDepth(Depth);
+	 ioprintf(clog, _("Could not perform immediate configuration on '%s'. "
+			   "Please see man 5 apt.conf under APT::Immediate-Configure for details. (%d)"),
+			 Pkg.FullName().c_str(), 2);
+	 clog << endl;
+      }
+   }
+   
+   return true;
+}
+									/*}}}*/
+// PM::OrderInstall - Installation ordering routine			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgPackageManager::OrderResult pkgPackageManager::OrderInstall()
+{
+   if (CreateOrderList() == false)
+      return Failed;
+
+   Reset();
+
+   if (Debug == true)
+      clog << "Beginning to order" << endl;
+
+   std::string const planner = _config->Find("APT::Planner", "internal");
+   unsigned int flags = 0;
+   if (_config->FindB("APT::Immediate-Configure", true) == false)
+      flags |= EIPP::Request::NO_IMMEDIATE_CONFIGURATION;
+   else if (_config->FindB("APT::Immediate-Configure-All", false))
+      flags |= EIPP::Request::IMMEDIATE_CONFIGURATION_ALL;
+   else if (_config->FindB("APT::Force-LoopBreak", false))
+      flags |= EIPP::Request::ALLOW_TEMPORARY_REMOVE_OF_ESSENTIALS;
+   auto const ret = EIPP::OrderInstall(planner.c_str(), this, flags, nullptr);
+   if (planner != "internal")
+      return ret ? Completed : Failed;
+
+   bool const ordering =
+	_config->FindB("PackageManager::UnpackAll",true) ?
+		List->OrderUnpack(FileNames) : List->OrderCritical();
+   if (ordering == false)
+   {
+      _error->Error("Internal ordering error");
+      return Failed;
+   }
+
+   if (Debug == true)
+      clog << "Done ordering" << endl;
+
+   bool DoneSomething = false;
+   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
+   {
+      PkgIterator Pkg(Cache,*I);
+
+      if (List->IsNow(Pkg) == false)
+      {
+	 if (Debug == true)
+	    clog << "Skipping already done " << Pkg.FullName() << endl;
+	 continue;
+      }
+
+      if (List->IsMissing(Pkg) == true)
+      {
+	 if (Debug == true)
+	    clog << "Sequence completed at " << Pkg.FullName() << endl;
+	 if (DoneSomething == false)
+	 {
+	    _error->Error("Internal Error, ordering was unable to handle the media swap");
+	    return Failed;
+	 }	 
+	 return Incomplete;
+      }
+      
+      // Sanity check
+      if (Cache[Pkg].Keep() == true && 
+	  Pkg.State() == pkgCache::PkgIterator::NeedsNothing &&
+	  (Cache[Pkg].iFlags & pkgDepCache::ReInstall) != pkgDepCache::ReInstall)
+      {
+	 _error->Error("Internal Error, trying to manipulate a kept package (%s)",Pkg.FullName().c_str());
+	 return Failed;
+      }
+      
+      // Perform a delete or an install
+      if (Cache[Pkg].Delete() == true)
+      {
+	 if (SmartRemove(Pkg) == false)
+	    return Failed;
+      }
+      else
+	 if (SmartUnPack(Pkg,List->IsFlag(Pkg,pkgOrderList::Immediate),0) == false)
+	    return Failed;
+      DoneSomething = true;
+      
+      if (ImmConfigureAll) {
+         /* ConfigureAll here to pick up and packages left unconfigured because they were unpacked in the
+            "PreUnpack Checks" section */
+         if (!ConfigureAll())
+            return Failed; 
+      }
+   }
+
+   // Final run through the configure phase
+   if (ConfigureAll() == false)
+      return Failed;
+
+   // Sanity check
+   for (pkgOrderList::iterator I = List->begin(); I != List->end(); ++I)
+   {
+      if (List->IsFlag(*I,pkgOrderList::Configured) == false)
+      {
+	 _error->Error("Internal error, packages left unconfigured. %s",
+		       PkgIterator(Cache,*I).FullName().c_str());
+	 return Failed;
+      }
+   }
+	 
+   return Completed;
+}
+// PM::DoInstallPostFork - Does install part that happens after the fork /*{{{*/
+// ---------------------------------------------------------------------
+pkgPackageManager::OrderResult 
+pkgPackageManager::DoInstallPostFork(APT::Progress::PackageManager *progress)
+{
+   bool goResult;
+   goResult = Go(progress);
+   if(goResult == false) 
+      return Failed;
+   
+   return Res;
+}
+									/*}}}*/	
+// PM::DoInstall - Does the installation				/*{{{*/
+// ---------------------------------------------------------------------
+/* This uses the filenames in FileNames and the information in the
+   DepCache to perform the installation of packages.*/
+pkgPackageManager::OrderResult 
+pkgPackageManager::DoInstall(APT::Progress::PackageManager *progress)
+{
+   if(DoInstallPreFork() == Failed)
+      return Failed;
+   
+   return DoInstallPostFork(progress);
+}
+									/*}}}*/	      
diff --git a/apt-pkg/packagemanager.h b/apt-pkg/packagemanager.h
new file mode 100644
index 0000000..d4cc3c6
--- /dev/null
+++ b/apt-pkg/packagemanager.h
@@ -0,0 +1,138 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Package Manager - Abstracts the package manager
+
+   Three steps are 
+     - Aquiration of archives (stores the list of final file names)
+     - Sorting of operations
+     - Invocation of package manager
+   
+   This is the final stage when the package cache entities get converted
+   into file names and the state stored in a DepCache is transformed
+   into a series of operations.
+
+   In the final scheme of things this may serve as a director class to
+   access the actual install methods based on the file type being
+   installed.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PACKAGEMANAGER_H
+#define PKGLIB_PACKAGEMANAGER_H
+
+#include <apt-pkg/edsp.h>
+#include <apt-pkg/init.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <set>
+#include <string>
+
+
+class pkgAcquire;
+class pkgDepCache;
+class pkgSourceList;
+class pkgOrderList;
+class pkgRecords;
+class OpProgress;
+class pkgPackageManager;
+namespace APT {
+   namespace Progress {
+      class PackageManager;
+   }
+}
+
+class APT_PUBLIC pkgPackageManager : protected pkgCache::Namespace
+{
+   public:
+   
+   enum OrderResult {Completed,Failed,Incomplete};
+   static bool SigINTStop;
+   
+   protected:
+   std::string *FileNames;
+   pkgDepCache &Cache;
+   pkgOrderList *List;
+   bool Debug;
+   bool NoImmConfigure;
+   bool ImmConfigureAll;
+
+   /** \brief saves packages dpkg let disappear
+
+       This way APT can retreat from trying to configure these
+       packages later on and a front-end can choose to display a
+       notice to inform the user about these disappears.
+   */
+   std::set<std::string> disappearedPkgs;
+
+   void ImmediateAdd(PkgIterator P, bool UseInstallVer, unsigned const int &Depth = 0);
+   virtual OrderResult OrderInstall();
+   bool CheckRConflicts(PkgIterator Pkg,DepIterator Dep,const char *Ver);
+   bool CheckRBreaks(PkgIterator const &Pkg,DepIterator Dep,const char * const Ver);
+   bool CreateOrderList();
+   
+   // Analysis helpers
+   bool DepAlwaysTrue(DepIterator D) APT_PURE;
+   
+   // Install helpers
+   bool ConfigureAll();
+   bool SmartConfigure(PkgIterator Pkg, int const Depth) APT_MUSTCHECK;
+   bool SmartUnPack(PkgIterator Pkg, bool const Immediate = true, int const Depth = 0) APT_MUSTCHECK;
+   bool SmartRemove(PkgIterator Pkg) APT_MUSTCHECK;
+   bool EarlyRemove(PkgIterator Pkg, DepIterator const * const Dep) APT_MUSTCHECK;
+
+   // The Actual installation implementation
+   virtual bool Install(PkgIterator /*Pkg*/,std::string /*File*/) {return false;};
+   virtual bool Configure(PkgIterator /*Pkg*/) {return false;};
+   virtual bool Remove(PkgIterator /*Pkg*/,bool /*Purge*/=false) {return false;};
+   virtual bool Go(APT::Progress::PackageManager * /*progress*/) {return true;};
+
+   virtual void Reset() {};
+
+   // the result of the operation
+   OrderResult Res;
+
+   public:
+      
+   // Main action members
+   bool GetArchives(pkgAcquire *Owner,pkgSourceList *Sources,
+		    pkgRecords *Recs);
+
+   // Do the installation
+   OrderResult DoInstall(APT::Progress::PackageManager *progress);
+
+   friend bool EIPP::OrderInstall(char const * const planner, pkgPackageManager * const PM,
+	 unsigned int const version, OpProgress * const Progress);
+   friend bool EIPP::ReadResponse(int const input, pkgPackageManager * const PM,
+	 OpProgress * const Progress);
+
+   // stuff that needs to be done before the fork() of a library that
+   // uses apt
+   OrderResult DoInstallPreFork() {
+      Res = OrderInstall();
+      return Res;
+   };
+   // stuff that needs to be done after the fork
+   OrderResult DoInstallPostFork(APT::Progress::PackageManager *progress);
+   // compat
+
+   // ?
+   bool FixMissing();
+
+   /** \brief returns all packages dpkg let disappear */
+   inline std::set<std::string> GetDisappearedPackages() { return disappearedPkgs; };
+
+   explicit pkgPackageManager(pkgDepCache *Cache);
+   virtual ~pkgPackageManager();
+
+   private:
+   void * const d;
+   enum APT_HIDDEN SmartAction { UNPACK_IMMEDIATE, UNPACK, CONFIGURE };
+   APT_HIDDEN bool NonLoopingSmart(SmartAction const action, pkgCache::PkgIterator &Pkg,
+      pkgCache::PkgIterator DepPkg, int const Depth, bool const PkgLoop,
+      bool * const Bad, bool * const Changed) APT_MUSTCHECK;
+};
+
+#endif
diff --git a/apt-pkg/pkgcache.cc b/apt-pkg/pkgcache.cc
new file mode 100644
index 0000000..0d18c6c
--- /dev/null
+++ b/apt-pkg/pkgcache.cc
@@ -0,0 +1,1011 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Cache - Accessor code for the cache
+   
+   Please see doc/apt-pkg/cache.sgml for a more detailed description of 
+   this format. Also be sure to keep that file up-to-date!!
+   
+   This is the general utility functions for cache management. They provide
+   a complete set of accessor functions for the cache. The cacheiterators
+   header contains the STL-like iterators that can be used to easially
+   navigate the cache as well as seamlessly dereference the mmap'd
+   indexes. Use these always.
+   
+   The main class provides for ways to get package indexes and some
+   general lookup functions to start the iterators.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/mmap.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/policy.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/version.h>
+
+#include <algorithm>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <stddef.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <xxhash.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+using APT::StringView;
+
+
+// Cache::Header::Header - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* Simply initialize the header */
+pkgCache::Header::Header()
+{
+#define APT_HEADER_SET(X,Y) X = Y; static_assert(std::numeric_limits<decltype(X)>::max() > Y, "Size violation detected in pkgCache::Header")
+   APT_HEADER_SET(Signature, 0x98FE76DC);
+
+   /* Whenever the structures change the major version should be bumped,
+      whenever the generator changes the minor version should be bumped. */
+   APT_HEADER_SET(MajorVersion, 16);
+   APT_HEADER_SET(MinorVersion, 0);
+   APT_HEADER_SET(Dirty, false);
+
+   APT_HEADER_SET(HeaderSz, sizeof(pkgCache::Header));
+   APT_HEADER_SET(GroupSz, sizeof(pkgCache::Group));
+   APT_HEADER_SET(PackageSz, sizeof(pkgCache::Package));
+   APT_HEADER_SET(ReleaseFileSz, sizeof(pkgCache::ReleaseFile));
+   APT_HEADER_SET(PackageFileSz, sizeof(pkgCache::PackageFile));
+   APT_HEADER_SET(VersionSz, sizeof(pkgCache::Version));
+   APT_HEADER_SET(DescriptionSz, sizeof(pkgCache::Description));
+   APT_HEADER_SET(DependencySz, sizeof(pkgCache::Dependency));
+   APT_HEADER_SET(DependencyDataSz, sizeof(pkgCache::DependencyData));
+   APT_HEADER_SET(ProvidesSz, sizeof(pkgCache::Provides));
+   APT_HEADER_SET(VerFileSz, sizeof(pkgCache::VerFile));
+   APT_HEADER_SET(DescFileSz, sizeof(pkgCache::DescFile));
+#undef APT_HEADER_SET
+
+   GroupCount = 0;
+   PackageCount = 0;
+   VersionCount = 0;
+   DescriptionCount = 0;
+   DependsCount = 0;
+   DependsDataCount = 0;
+   ReleaseFileCount = 0;
+   PackageFileCount = 0;
+   VerFileCount = 0;
+   DescFileCount = 0;
+   ProvidesCount = 0;
+   MaxVerFileSize = 0;
+   MaxDescFileSize = 0;
+
+   FileList = 0;
+   RlsFileList = 0;
+   VerSysName = 0;
+   Architecture = 0;
+   SetArchitectures(0);
+   SetHashTableSize(_config->FindI("APT::Cache-HashTableSize", 196613));
+   memset(Pools,0,sizeof(Pools));
+
+   CacheFileSize = 0;
+}
+									/*}}}*/
+// Cache::Header::CheckSizes - Check if the two headers have same *sz	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCache::Header::CheckSizes(Header &Against) const
+{
+   if (HeaderSz == Against.HeaderSz &&
+       GroupSz == Against.GroupSz &&
+       PackageSz == Against.PackageSz &&
+       ReleaseFileSz == Against.ReleaseFileSz &&
+       PackageFileSz == Against.PackageFileSz &&
+       VersionSz == Against.VersionSz &&
+       DescriptionSz == Against.DescriptionSz &&
+       DependencySz == Against.DependencySz &&
+       DependencyDataSz == Against.DependencyDataSz &&
+       VerFileSz == Against.VerFileSz &&
+       DescFileSz == Against.DescFileSz &&
+       ProvidesSz == Against.ProvidesSz)
+      return true;
+   return false;
+}
+									/*}}}*/
+
+// Cache::pkgCache - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgCache::pkgCache(MMap *Map, bool DoMap) : Map(*Map), VS(nullptr), d(NULL)
+{
+   // call getArchitectures() with cached=false to ensure that the 
+   // architectures cache is re-evaluated. this is needed in cases
+   // when the APT::Architecture field changes between two cache creations
+   APT::Configuration::getArchitectures(false);
+   MultiArchEnabled = true;
+   if (DoMap == true)
+      ReMap();
+}
+									/*}}}*/
+// Cache::ReMap - Reopen the cache file					/*{{{*/
+// ---------------------------------------------------------------------
+/* If the file is already closed then this will open it open it. */
+bool pkgCache::ReMap(bool const &Errorchecks)
+{
+   // Apply the typecasts.
+   HeaderP = (Header *)Map.Data();
+   GrpP = (Group *)Map.Data();
+   PkgP = (Package *)Map.Data();
+   VerFileP = (VerFile *)Map.Data();
+   DescFileP = (DescFile *)Map.Data();
+   RlsFileP = (ReleaseFile *)Map.Data();
+   PkgFileP = (PackageFile *)Map.Data();
+   VerP = (Version *)Map.Data();
+   DescP = (Description *)Map.Data();
+   ProvideP = (Provides *)Map.Data();
+   DepP = (Dependency *)Map.Data();
+   DepDataP = (DependencyData *)Map.Data();
+   StrP = (char *)Map.Data();
+
+   if (Errorchecks == false)
+      return true;
+
+   if (Map.Size() == 0 || HeaderP == 0)
+      return _error->Error(_("Empty package cache"));
+   
+   // Check the header
+   Header DefHeader;
+   if (HeaderP->Signature != DefHeader.Signature ||
+       HeaderP->Dirty == true)
+      return _error->Error(_("The package cache file is corrupted"));
+   
+   if (HeaderP->MajorVersion != DefHeader.MajorVersion ||
+       HeaderP->MinorVersion != DefHeader.MinorVersion ||
+       HeaderP->CheckSizes(DefHeader) == false)
+      return _error->Error(_("The package cache file is an incompatible version"));
+
+   if (HeaderP->VerSysName == 0 || HeaderP->Architecture == 0 || HeaderP->GetArchitectures() == 0)
+      return _error->Error(_("The package cache file is corrupted"));
+
+   // Locate our VS..
+   if ((VS = pkgVersioningSystem::GetVS(StrP + HeaderP->VerSysName)) == 0)
+      return _error->Error(_("This APT does not support the versioning system '%s'"),StrP + HeaderP->VerSysName);
+
+   // Check the architecture
+   std::vector<std::string> archs = APT::Configuration::getArchitectures();
+   std::string list = "";
+   for (auto const & arch : archs) {
+      if (!list.empty())
+         list.append(",");
+      list.append(arch);
+   }
+   if (_config->Find("APT::Architecture") != StrP + HeaderP->Architecture ||
+	 list != StrP + HeaderP->GetArchitectures())
+      return _error->Error(_("The package cache was built for different architectures: %s vs %s"), StrP + HeaderP->GetArchitectures(), list.c_str());
+
+
+   auto hash = CacheHash();
+   if (_config->FindB("Debug::pkgCacheGen", false))
+      std::clog << "Opened cache with hash " << hash << ", expecting " <<  HeaderP->CacheFileSize << "\n";
+   if (hash != HeaderP->CacheFileSize)
+      return _error->Error(_("The package cache file is corrupted, it has the wrong hash"));
+
+   return true;
+}
+									/*}}}*/
+// Cache::Hash - Hash a string						/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to generate the hash entries for the HashTable. With my
+   package list from bo this function gets 94% table usage on a 512 item
+   table (480 used items) */
+map_id_t pkgCache::sHash(StringView Str) const
+{
+   uint32_t Hash = 5381;
+   auto I = Str.begin();
+   auto End = Str.end();
+   for (; I + 7 < End; I += 8)
+   {
+      Hash = (33u * 33u * 33u * 33u * 33u * 33u * 33u * 33u * Hash +
+	      33u * 33u * 33u * 33u * 33u * 33u * 33u * tolower_ascii_unsafe(I[0]) +
+	      33u * 33u * 33u * 33u * 33u * 33u * tolower_ascii_unsafe(I[1]) +
+	      33u * 33u * 33u * 33u * 33u * tolower_ascii_unsafe(I[2]) +
+	      33u * 33u * 33u * 33u * tolower_ascii_unsafe(I[3]) +
+	      33u * 33u * 33u * tolower_ascii_unsafe(I[4]) +
+	      33u * 33u * tolower_ascii_unsafe(I[5]) +
+	      33u * tolower_ascii_unsafe(I[6]) +
+	      tolower_ascii_unsafe(I[7]));
+   }
+   for (; I != End; ++I)
+      Hash = 33u * Hash + tolower_ascii_unsafe(*I);
+   return Hash % HeaderP->GetHashTableSize();
+}
+uint32_t pkgCache::CacheHash()
+{
+   pkgCache::Header header = {};
+   XXH3_state_t *state = XXH3_createState();
+
+   if (Map.Size() < sizeof(header))
+      return 0;
+
+   XXH3_64bits_reset(state);
+   memcpy(&header, GetMap().Data(), sizeof(header));
+
+   header.Dirty = false;
+   header.CacheFileSize = 0;
+
+   XXH3_64bits_update(state,
+		      reinterpret_cast<const unsigned char *>(PACKAGE_VERSION),
+		      APT_ARRAY_SIZE(PACKAGE_VERSION));
+
+   XXH3_64bits_update(state,
+		      reinterpret_cast<const unsigned char *>(&header),
+		      sizeof(header));
+
+   if (Map.Size() > sizeof(header)) {
+      XXH3_64bits_update(state,
+			 static_cast<const unsigned char *>(GetMap().Data()) + sizeof(header),
+			 GetMap().Size() - sizeof(header));
+   }
+
+   auto const digest = XXH3_64bits_digest(state);
+   XXH3_freeState(state);
+   return digest & 0xFFFFFFFF;
+}
+									/*}}}*/
+// Cache::FindPkg - Locate a package by name				/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns 0 on error, pointer to the package otherwise */
+pkgCache::PkgIterator pkgCache::FindPkg(StringView Name) {
+	auto const found = Name.rfind(':');
+	if (found == string::npos)
+	   return FindPkg(Name, "native");
+	auto const Arch = Name.substr(found+1);
+	/* Beware: This is specialcased to handle pkg:any in dependencies
+	   as these are linked to virtual pkg:any named packages.
+	   If you want any arch from a pkg, use FindPkg(pkg,"any") */
+	if (Arch == "any")
+		return FindPkg(Name, "any");
+	return FindPkg(Name.substr(0, found), Arch);
+}
+									/*}}}*/
+// Cache::FindPkg - Locate a package by name				/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns 0 on error, pointer to the package otherwise */
+pkgCache::PkgIterator pkgCache::FindPkg(StringView Name, StringView Arch) {
+	/* We make a detour via the GrpIterator here as
+	   on a multi-arch environment a group is easier to
+	   find than a package (less entries in the buckets) */
+	pkgCache::GrpIterator Grp = FindGrp(Name);
+	if (Grp.end() == true)
+		return PkgIterator(*this,0);
+
+	return Grp.FindPkg(Arch);
+}
+									/*}}}*/
+// Cache::FindGrp - Locate a group by name				/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns End-Pointer on error, pointer to the group otherwise */
+pkgCache::GrpIterator pkgCache::FindGrp(StringView Name) {
+	if (unlikely(Name.empty() == true))
+		return GrpIterator(*this,0);
+
+	// Look at the hash bucket for the group
+	Group *Grp = GrpP + HeaderP->GrpHashTableP()[sHash(Name)];
+	for (; Grp != GrpP; Grp = GrpP + Grp->Next) {
+		int const cmp = StringViewCompareFast(Name, ViewString(Grp->Name));
+		if (cmp == 0)
+			return GrpIterator(*this, Grp);
+		else if (cmp < 0)
+			break;
+	}
+
+	return GrpIterator(*this,0);
+}
+									/*}}}*/
+// Cache::CompTypeDeb - Return a string describing the compare type	/*{{{*/
+// ---------------------------------------------------------------------
+/* This returns a string representation of the dependency compare 
+   type in the weird debian style.. */
+const char *pkgCache::CompTypeDeb(unsigned char Comp)
+{
+   const char * const Ops[] = {"","<=",">=","<<",">>","=","!="};
+   if (unlikely((unsigned)(Comp & 0xF) >= sizeof(Ops)/sizeof(Ops[0])))
+      return "";
+   return Ops[Comp & 0xF];
+}
+									/*}}}*/
+// Cache::CompType - Return a string describing the compare type	/*{{{*/
+// ---------------------------------------------------------------------
+/* This returns a string representation of the dependency compare
+   type */
+const char *pkgCache::CompType(unsigned char Comp)
+{
+   const char * const Ops[] = {"","<=",">=","<",">","=","!="};
+   if (unlikely((unsigned)(Comp & 0xF) >= sizeof(Ops)/sizeof(Ops[0])))
+      return "";
+   return Ops[Comp & 0xF];
+}
+									/*}}}*/
+// Cache::DepType - Return a string describing the dep type		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+const char *pkgCache::DepType(unsigned char Type)
+{
+   const char *Types[] = {"",_("Depends"),_("PreDepends"),_("Suggests"),
+                          _("Recommends"),_("Conflicts"),_("Replaces"),
+                          _("Obsoletes"),_("Breaks"), _("Enhances")};
+   if (Type < sizeof(Types)/sizeof(*Types))
+      return Types[Type];
+   return "";
+}
+									/*}}}*/
+// Cache::Priority - Convert a priority value to a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+const char *pkgCache::Priority(unsigned char Prio)
+{
+   const char *Mapping[] = {0,_("required"),_("important"),_("standard"),
+                            _("optional"),_("extra")};
+   if (Prio < APT_ARRAY_SIZE(Mapping))
+      return Mapping[Prio];
+   return 0;
+}
+									/*}}}*/
+// GrpIterator::FindPkg - Locate a package by arch			/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns an End-Pointer on error, pointer to the package otherwise */
+pkgCache::PkgIterator pkgCache::GrpIterator::FindPkg(StringView Arch) const {
+	if (unlikely(IsGood() == false || S->FirstPackage == 0))
+		return PkgIterator(*Owner, 0);
+
+	/* If we accept any package we simply return the "first"
+	   package in this group */
+	if (Arch == "any")
+		return PkgIterator(*Owner, Owner->PkgP + S->FirstPackage);
+	if (Arch == "native" || Arch == "all")
+               Arch = Owner->NativeArch();
+
+	// Iterate over the list to find the matching arch
+	for (pkgCache::Package *Pkg = PackageList(); Pkg != Owner->PkgP;
+	     Pkg = Owner->PkgP + Pkg->NextPackage) {
+		if (Arch == Owner->ViewString(Pkg->Arch))
+			return PkgIterator(*Owner, Pkg);
+		if ((Owner->PkgP + S->LastPackage) == Pkg)
+			break;
+	}
+
+	return PkgIterator(*Owner, 0);
+}
+									/*}}}*/
+// GrpIterator::FindPreferredPkg - Locate the "best" package		/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns an End-Pointer on error, pointer to the package otherwise */
+pkgCache::PkgIterator pkgCache::GrpIterator::FindPreferredPkg(bool const &PreferNonVirtual) const {
+	pkgCache::PkgIterator Pkg = FindPkg(StringView("native", 6));
+	if (Pkg.end() == false && (PreferNonVirtual == false || Pkg->VersionList != 0))
+		return Pkg;
+
+	std::vector<std::string> const archs = APT::Configuration::getArchitectures();
+	for (std::vector<std::string>::const_iterator a = archs.begin();
+	     a != archs.end(); ++a) {
+		Pkg = FindPkg(*a);
+		if (Pkg.end() == false && (PreferNonVirtual == false || Pkg->VersionList != 0))
+			return Pkg;
+	}
+	// packages without an architecture
+	Pkg = FindPkg(StringView("none", 4));
+	if (Pkg.end() == false && (PreferNonVirtual == false || Pkg->VersionList != 0))
+		return Pkg;
+
+	if (PreferNonVirtual == true)
+		return FindPreferredPkg(false);
+	return PkgIterator(*Owner, 0);
+}
+									/*}}}*/
+// GrpIterator::NextPkg - Locate the next package in the group		/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns an End-Pointer on error, pointer to the package otherwise.
+   We can't simply ++ to the next as the next package of the last will
+   be from a different group (with the same hash value) */
+pkgCache::PkgIterator pkgCache::GrpIterator::NextPkg(pkgCache::PkgIterator const &LastPkg) const {
+	if (unlikely(IsGood() == false || S->FirstPackage == 0 ||
+	    LastPkg.end() == true))
+		return PkgIterator(*Owner, 0);
+
+	if (S->LastPackage == LastPkg.MapPointer())
+		return PkgIterator(*Owner, 0);
+
+	return PkgIterator(*Owner, Owner->PkgP + LastPkg->NextPackage);
+}
+									/*}}}*/
+// GrpIterator::operator++ - Prefix incr				/*{{{*/
+// ---------------------------------------------------------------------
+/* This will advance to the next logical group in the hash table. */
+pkgCache::GrpIterator& pkgCache::GrpIterator::operator++()
+{
+   // Follow the current links
+   if (S != Owner->GrpP)
+      S = Owner->GrpP + S->Next;
+
+   // Follow the hash table
+   while (S == Owner->GrpP && (HashIndex+1) < (signed)Owner->HeaderP->GetHashTableSize())
+   {
+      ++HashIndex;
+      S = Owner->GrpP + Owner->HeaderP->GrpHashTableP()[HashIndex];
+   }
+   return *this;
+}
+									/*}}}*/
+// PkgIterator::operator++ - Prefix incr				/*{{{*/
+// ---------------------------------------------------------------------
+/* This will advance to the next logical package in the hash table. */
+pkgCache::PkgIterator& pkgCache::PkgIterator::operator++()
+{
+   // Follow the current links
+   if (S != Owner->PkgP)
+      S = Owner->PkgP + S->NextPackage;
+
+   // Follow the hash table
+   while (S == Owner->PkgP && (HashIndex+1) < (signed)Owner->HeaderP->GetHashTableSize())
+   {
+      ++HashIndex;
+      S = Owner->PkgP + Owner->HeaderP->PkgHashTableP()[HashIndex];
+   }
+   return *this;
+}
+									/*}}}*/
+pkgCache::DepIterator& pkgCache::DepIterator::operator++()		/*{{{*/
+{
+   if (S == Owner->DepP)
+      return *this;
+   S = Owner->DepP + (Type == DepVer ? S->NextDepends : S->NextRevDepends);
+   if (S == Owner->DepP)
+      S2 = Owner->DepDataP;
+   else
+      S2 = Owner->DepDataP + S->DependencyData;
+   return *this;
+}
+									/*}}}*/
+// PkgIterator::State - Check the State of the package			/*{{{*/
+// ---------------------------------------------------------------------
+/* By this we mean if it is either cleanly installed or cleanly removed. */
+pkgCache::PkgIterator::OkState pkgCache::PkgIterator::State() const
+{  
+   if (S->InstState == pkgCache::State::ReInstReq ||
+       S->InstState == pkgCache::State::HoldReInstReq)
+      return NeedsUnpack;
+   
+   if (S->CurrentState == pkgCache::State::UnPacked ||
+       S->CurrentState == pkgCache::State::HalfConfigured)
+      // we leave triggers alone completely. dpkg deals with
+      // them in a hard-to-predict manner and if they get 
+      // resolved by dpkg before apt run dpkg --configure on 
+      // the TriggersPending package dpkg returns a error
+      //Pkg->CurrentState == pkgCache::State::TriggersAwaited
+      //Pkg->CurrentState == pkgCache::State::TriggersPending)
+      return NeedsConfigure;
+   
+   if (S->CurrentState == pkgCache::State::HalfInstalled ||
+       S->InstState != pkgCache::State::Ok)
+      return NeedsUnpack;
+      
+   return NeedsNothing;
+}
+									/*}}}*/
+// PkgIterator::CurVersion - Returns the current version string		/*{{{*/
+// ---------------------------------------------------------------------
+/* Return string representing of the current version. */
+const char *
+pkgCache::PkgIterator::CurVersion() const
+{
+  VerIterator version = CurrentVer();
+  if (version.IsGood())
+    return CurrentVer().VerStr();
+  return 0;
+}
+									/*}}}*/
+// ostream operator to handle string representation of a package	/*{{{*/
+// ---------------------------------------------------------------------
+/* Output name < cur.rent.version -> candid.ate.version | new.est.version > (section)
+   Note that the characters <|>() are all literal above. Versions will be omitted
+   if they provide no new information (e.g. there is no newer version than candidate)
+   If no version and/or section can be found "none" is used. */
+std::ostream& 
+operator<<(std::ostream& out, pkgCache::PkgIterator Pkg) 
+{
+   if (Pkg.end() == true)
+      return out << "invalid package";
+
+   string current = string(Pkg.CurVersion() == 0 ? "none" : Pkg.CurVersion());
+   string newest = string(Pkg.VersionList().end() ? "none" : Pkg.VersionList().VerStr());
+
+   out << Pkg.Name() << " [ " << Pkg.Arch() << " ] < " << current;
+   if ( newest != "none")
+      out << " | " << newest;
+   if (Pkg->VersionList == 0)
+      out << " > ( none )";
+   else
+      out << " > ( " << string(Pkg.VersionList().Section()==0?"unknown":Pkg.VersionList().Section()) << " )";
+   return out;
+}
+									/*}}}*/
+// PkgIterator::FullName - Returns Name and (maybe) Architecture	/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns a name:arch string */
+std::string pkgCache::PkgIterator::FullName(bool const &Pretty) const
+{
+   string fullname = Name();
+   if (Pretty == false ||
+       (strcmp(Arch(), "all") != 0 && strcmp(Arch(), "any") != 0 &&
+	strcmp(Owner->NativeArch(), Arch()) != 0))
+      return fullname.append(":").append(Arch());
+   return fullname;
+}
+									/*}}}*/
+// DepIterator::IsCritical - Returns true if the dep is important	/*{{{*/
+// ---------------------------------------------------------------------
+/* Currently critical deps are defined as depends, predepends and
+   conflicts (including dpkg's Breaks fields). */
+bool pkgCache::DepIterator::IsCritical() const
+{
+   if (IsNegative() == true ||
+       S2->Type == pkgCache::Dep::Depends ||
+       S2->Type == pkgCache::Dep::PreDepends)
+      return true;
+   return false;
+}
+									/*}}}*/
+// DepIterator::IsNegative - Returns true if the dep is a negative one	/*{{{*/
+// ---------------------------------------------------------------------
+/* Some dependencies are positive like Depends and Recommends, others
+   are negative like Conflicts which can and should be handled differently */
+bool pkgCache::DepIterator::IsNegative() const
+{
+   return S2->Type == Dep::DpkgBreaks ||
+	  S2->Type == Dep::Conflicts ||
+	  S2->Type == Dep::Obsoletes;
+}
+									/*}}}*/
+// DepIterator::SmartTargetPkg - Resolve dep target pointers w/provides	/*{{{*/
+// ---------------------------------------------------------------------
+/* This intellegently looks at dep target packages and tries to figure
+   out which package should be used. This is needed to nicely handle
+   provide mapping. If the target package has no other providing packages
+   then it returned. Otherwise the providing list is looked at to
+   see if there is one unique providing package if so it is returned.
+   Otherwise true is returned and the target package is set. The return
+   result indicates whether the node should be expandable 
+ 
+   In Conjunction with the DepCache the value of Result may not be 
+   super-good since the policy may have made it uninstallable. Using
+   AllTargets is better in this case. */
+bool pkgCache::DepIterator::SmartTargetPkg(PkgIterator &Result) const
+{
+   Result = TargetPkg();
+   
+   // No provides at all
+   if (Result->ProvidesList == 0)
+      return false;
+   
+   // There is the Base package and the providing ones which is at least 2
+   if (Result->VersionList != 0)
+      return true;
+      
+   /* We have to skip over indirect provisions of the package that
+      owns the dependency. For instance, if libc5-dev depends on the
+      virtual package libc-dev which is provided by libc5-dev and libc6-dev
+      we must ignore libc5-dev when considering the provides list. */ 
+   PrvIterator PStart = Result.ProvidesList();
+   for (; PStart.end() != true && PStart.OwnerPkg() == ParentPkg(); ++PStart);
+
+   // Nothing but indirect self provides
+   if (PStart.end() == true)
+      return false;
+   
+   // Check for single packages in the provides list
+   PrvIterator P = PStart;
+   for (; P.end() != true; ++P)
+   {
+      // Skip over self provides
+      if (P.OwnerPkg() == ParentPkg())
+	 continue;
+      if (PStart.OwnerPkg() != P.OwnerPkg())
+	 break;
+   }
+
+   Result = PStart.OwnerPkg();
+   
+   // Check for non dups
+   if (P.end() != true)
+      return true;
+   
+   return false;
+}
+									/*}}}*/
+// DepIterator::AllTargets - Returns the set of all possible targets	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a more useful version of TargetPkg() that follows versioned
+   provides. It includes every possible package-version that could satisfy
+   the dependency. The last item in the list has a 0. The resulting pointer
+   must be delete [] 'd */
+pkgCache::Version **pkgCache::DepIterator::AllTargets() const
+{
+   Version **Res = 0;
+   unsigned long Size =0;
+   while (1)
+   {
+      Version **End = Res;
+      PkgIterator DPkg = TargetPkg();
+
+      // Walk along the actual package providing versions
+      for (VerIterator I = DPkg.VersionList(); I.end() == false; ++I)
+      {
+	 if (IsIgnorable(I.ParentPkg()) == true)
+	    continue;
+	 if (IsSatisfied(I) == false)
+	    continue;
+
+	 Size++;
+	 if (Res != 0)
+	    *End++ = I;
+      }
+      
+      // Follow all provides
+      for (PrvIterator I = DPkg.ProvidesList(); I.end() == false; ++I)
+      {
+	 if (IsIgnorable(I) == true)
+	    continue;
+	 if (IsSatisfied(I) == false)
+	    continue;
+
+	 Size++;
+	 if (Res != 0)
+	    *End++ = I.OwnerVer();
+      }
+      
+      // Do it again and write it into the array
+      if (Res == 0)
+      {
+	 Res = new Version *[Size+1];
+	 Size = 0;
+      }
+      else
+      {
+	 *End = 0;
+	 break;
+      }      
+   }
+   
+   return Res;
+}
+									/*}}}*/
+// DepIterator::GlobOr - Compute an OR group				/*{{{*/
+// ---------------------------------------------------------------------
+/* This Takes an iterator, iterates past the current dependency grouping
+   and returns Start and End so that so End is the final element
+   in the group, if End == Start then D is End++ and End is the
+   dependency D was pointing to. Use in loops to iterate sensibly. */
+void pkgCache::DepIterator::GlobOr(DepIterator &Start,DepIterator &End)
+{
+   // Compute a single dependency element (glob or)
+   Start = *this;
+   End = *this;
+   for (bool LastOR = true; end() == false && LastOR == true;)
+   {
+      LastOR = (S2->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or;
+      ++(*this);
+      if (LastOR == true)
+	 End = (*this);
+   }
+}
+									/*}}}*/
+// DepIterator::IsIgnorable - should this packag/providr be ignored?	/*{{{*/
+// ---------------------------------------------------------------------
+/* Deps like self-conflicts should be ignored as well as implicit conflicts
+   on virtual packages. */
+bool pkgCache::DepIterator::IsIgnorable(PkgIterator const &PT) const
+{
+   if (IsNegative() == false)
+      return false;
+
+   pkgCache::PkgIterator const PP = ParentPkg();
+   if (PP->Group != PT->Group)
+      return false;
+   // self-conflict
+   if (PP == PT)
+      return true;
+   pkgCache::VerIterator const PV = ParentVer();
+   // ignore group-conflict on a M-A:same package - but not our implicit dependencies
+   // so that we can have M-A:same packages conflicting with their own real name
+   if ((PV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+      return IsMultiArchImplicit() == false;
+
+   return false;
+}
+bool pkgCache::DepIterator::IsIgnorable(PrvIterator const &Prv) const
+{
+   if (IsNegative() == false)
+      return false;
+
+   PkgIterator const Pkg = ParentPkg();
+   /* Provides may never be applied against the same package (or group)
+      if it is a conflicts. See the comment above. */
+   if (Prv.OwnerPkg()->Group == Pkg->Group)
+      return true;
+   // Implicit group-conflicts should not be applied on providers of other groups
+   if (IsMultiArchImplicit() && Prv.OwnerPkg()->Group != Pkg->Group)
+      return true;
+
+   return false;
+}
+									/*}}}*/
+// DepIterator::IsSatisfied - check if a version satisfied the dependency /*{{{*/
+bool pkgCache::DepIterator::IsSatisfied(VerIterator const &Ver) const
+{
+   return Owner->VS->CheckDep(Ver.VerStr(),S2->CompareOp,TargetVer());
+}
+bool pkgCache::DepIterator::IsSatisfied(PrvIterator const &Prv) const
+{
+   return Owner->VS->CheckDep(Prv.ProvideVersion(),S2->CompareOp,TargetVer());
+}
+									/*}}}*/
+// DepIterator::IsImplicit - added by the cache generation		/*{{{*/
+bool pkgCache::DepIterator::IsImplicit() const
+{
+   if (IsMultiArchImplicit() == true)
+      return true;
+   if (IsNegative() || S2->Type == pkgCache::Dep::Replaces)
+   {
+      if ((S2->CompareOp & pkgCache::Dep::ArchSpecific) != pkgCache::Dep::ArchSpecific &&
+	    strcmp(ParentPkg().Arch(), TargetPkg().Arch()) != 0)
+	 return true;
+   }
+   return false;
+}
+									/*}}}*/
+// ostream operator to handle string representation of a dependency	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+std::ostream& operator<<(std::ostream& out, pkgCache::DepIterator D)
+{
+   if (D.end() == true)
+      return out << "invalid dependency";
+
+   pkgCache::PkgIterator P = D.ParentPkg();
+   pkgCache::PkgIterator T = D.TargetPkg();
+
+   out << (P.end() ? "invalid pkg" : P.FullName(false)) << " " << D.DepType()
+	<< " on ";
+APT_IGNORE_DEPRECATED_PUSH
+   if (T.end() == true)
+      out << "invalid pkg";
+   else
+      out << T;
+APT_IGNORE_DEPRECATED_POP
+
+   if (D->Version != 0)
+      out << " (" << D.CompType() << " " << D.TargetVer() << ")";
+
+   return out;
+}
+									/*}}}*/
+// VerIterator::CompareVer - Fast version compare for same pkgs		/*{{{*/
+// ---------------------------------------------------------------------
+/* This just looks over the version list to see if B is listed before A. In
+   most cases this will return in under 4 checks, ver lists are short. */
+int pkgCache::VerIterator::CompareVer(const VerIterator &B) const
+{
+   // Check if they are equal
+   if (*this == B)
+      return 0;
+   if (end() == true)
+      return -1;
+   if (B.end() == true)
+      return 1;
+       
+   /* Start at A and look for B. If B is found then A > B otherwise
+      B was before A so A < B */
+   VerIterator I = *this;
+   for (;I.end() == false; ++I)
+      if (I == B)
+	 return 1;
+   return -1;
+}
+									/*}}}*/
+// VerIterator::Downloadable - Checks if the version is downloadable	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+APT_PURE bool pkgCache::VerIterator::Downloadable() const
+{
+   VerFileIterator Files = FileList();
+   for (; Files.end() == false; ++Files)
+      if (Files.File().Flagged(pkgCache::Flag::NotSource) == false)
+	 return true;
+   return false;
+}
+									/*}}}*/
+// VerIterator::Automatic - Check if this version is 'automatic'	/*{{{*/
+// ---------------------------------------------------------------------
+/* This checks to see if any of the versions files are not NotAutomatic. 
+   True if this version is selectable for automatic installation. */
+APT_PURE bool pkgCache::VerIterator::Automatic() const
+{
+   VerFileIterator Files = FileList();
+   for (; Files.end() == false; ++Files)
+      // Do not check ButAutomaticUpgrades here as it is kind of automatic…
+      if (Files.File().Flagged(pkgCache::Flag::NotAutomatic) == false)
+	 return true;
+   return false;
+}
+									/*}}}*/
+// VerIterator::NewestFile - Return the newest file version relation	/*{{{*/
+// ---------------------------------------------------------------------
+/* This looks at the version numbers associated with all of the sources
+   this version is in and returns the highest.*/
+pkgCache::VerFileIterator pkgCache::VerIterator::NewestFile() const
+{
+   VerFileIterator Files = FileList();
+   VerFileIterator Highest = Files;
+   for (; Files.end() == false; ++Files)
+   {
+      if (Owner->VS->CmpReleaseVer(Files.File().Version(),Highest.File().Version()) > 0)
+	 Highest = Files;
+   }
+   
+   return Highest;
+}
+									/*}}}*/
+// VerIterator::RelStr - Release description string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This describes the version from a release-centric manner. The output is a 
+   list of Label:Version/Archive */
+static std::string PkgFileIteratorToRelString(pkgCache::PkgFileIterator const &File)
+{
+   std::string Res;
+   if (File.Label() != 0)
+      Res = Res + File.Label() + ':';
+
+   if (File.Archive() != 0)
+   {
+      if (File.Version() == 0)
+	 Res += File.Archive();
+      else
+	 Res = Res + File.Version() + '/' +  File.Archive();
+   }
+   else
+   {
+      // No release file, print the host name that this came from
+      if (File.Site() == 0 || File.Site()[0] == 0)
+	 Res += "localhost";
+      else
+	 Res += File.Site();
+   }
+   return Res;
+}
+string pkgCache::VerIterator::RelStr() const
+{
+   std::vector<std::string> RelStrs;
+   for (pkgCache::VerFileIterator I = this->FileList(); I.end() == false; ++I)
+   {
+      // Do not print 'not source' entries'
+      pkgCache::PkgFileIterator const File = I.File();
+      if (File.Flagged(pkgCache::Flag::NotSource))
+	 continue;
+
+      std::string const RS = PkgFileIteratorToRelString(File);
+      if (std::find(RelStrs.begin(), RelStrs.end(), RS) != RelStrs.end())
+	 continue;
+
+      RelStrs.push_back(RS);
+   }
+   std::ostringstream os;
+   if (likely(RelStrs.empty() == false))
+   {
+      std::copy(RelStrs.begin(), RelStrs.end()-1, std::ostream_iterator<std::string>(os, ", "));
+      os << *RelStrs.rbegin();
+   }
+   if (S->ParentPkg != 0)
+      os << " [" << Arch() << "]";
+   return os.str();
+}
+									/*}}}*/
+// VerIterator::MultiArchType - string representing MultiArch flag	/*{{{*/
+const char * pkgCache::VerIterator::MultiArchType() const
+{
+   if ((S->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
+      return "same";
+   else if ((S->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign)
+      return "foreign";
+   else if ((S->MultiArch & pkgCache::Version::Allowed) == pkgCache::Version::Allowed)
+      return "allowed";
+   return "none";
+}
+									/*}}}*/
+// RlsFileIterator::RelStr - Return the release string			/*{{{*/
+string pkgCache::RlsFileIterator::RelStr()
+{
+   string Res;
+   if (Version() != 0)
+      Res = Res + (Res.empty() == true?"v=":",v=") + Version();
+   if (Origin() != 0)
+      Res = Res + (Res.empty() == true?"o=":",o=")  + Origin();
+   if (Archive() != 0)
+      Res = Res + (Res.empty() == true?"a=":",a=")  + Archive();
+   if (Codename() != 0)
+      Res = Res + (Res.empty() == true?"n=":",n=")  + Codename();
+   if (Label() != 0)
+      Res = Res + (Res.empty() == true?"l=":",l=")  + Label();
+   return Res;
+}
+									/*}}}*/
+string pkgCache::PkgFileIterator::RelStr()				/*{{{*/
+{
+   std::string Res;
+   if (ReleaseFile() == 0)
+   {
+      if (Component() != 0)
+	 Res = Res + (Res.empty() == true?"a=":",a=")  + Component();
+   }
+   else
+   {
+      Res = ReleaseFile().RelStr();
+      if (Component() != 0)
+	 Res = Res + (Res.empty() == true?"c=":",c=")  + Component();
+   }
+   if (Architecture() != 0)
+      Res = Res + (Res.empty() == true?"b=":",b=")  + Architecture();
+   return Res;
+}
+									/*}}}*/
+// VerIterator::TranslatedDescriptionForLanguage - Return a DescIter for language/*{{{*/
+// ---------------------------------------------------------------------
+/* return a DescIter for the specified language
+ */
+pkgCache::DescIterator pkgCache::VerIterator::TranslatedDescriptionForLanguage(StringView lang) const
+{
+   for (pkgCache::DescIterator Desc = DescriptionList(); Desc.end() == false; ++Desc)
+      if (lang == Desc.LanguageCode())
+         return Desc;
+
+   if (lang == "en")
+      return TranslatedDescriptionForLanguage("");
+
+   return DescIterator();
+}
+
+									/*}}}*/
+// VerIterator::TranslatedDescription - Return the a DescIter for locale/*{{{*/
+// ---------------------------------------------------------------------
+/* return a DescIter for the current locale or the default if none is
+ * found
+ */
+pkgCache::DescIterator pkgCache::VerIterator::TranslatedDescription() const
+{
+   std::vector<string> const lang = APT::Configuration::getLanguages();
+   for (std::vector<string>::const_iterator l = lang.begin();
+	l != lang.end(); ++l)
+   {
+      pkgCache::DescIterator Desc = TranslatedDescriptionForLanguage(*l);
+      if (Desc.IsGood())
+         return Desc;
+   }
+
+   pkgCache::DescIterator Desc = TranslatedDescriptionForLanguage("");
+   if (Desc.IsGood())
+      return Desc;
+
+   return DescriptionList();
+}
+
+									/*}}}*/
+
+pkgCache::~pkgCache() {}
diff --git a/apt-pkg/pkgcache.h b/apt-pkg/pkgcache.h
new file mode 100644
index 0000000..55baa3c
--- /dev/null
+++ b/apt-pkg/pkgcache.h
@@ -0,0 +1,846 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/**\file pkgcache.h
+   \brief pkgCache - Structure definitions for the cache file
+
+   The goal of the cache file is two fold:
+   Firstly to speed loading and processing of the package file array and
+   secondly to reduce memory consumption of the package file array.
+
+   The implementation is aimed at an environment with many primary package
+   files, for instance someone that has a Package file for their CD-ROM, a
+   Package file for the latest version of the distribution on the CD-ROM and a
+   package file for the development version. Always present is the information
+   contained in the status file which might be considered a separate package
+   file.
+
+   Please understand, this is designed as a <b>Cache file</b> it is not meant to be
+   used on any system other than the one it was created for. It is not meant to
+   be authoritative either, i.e. if a system crash or software failure occurs it
+   must be perfectly acceptable for the cache file to be in an inconsistent
+   state. Furthermore at any time the cache file may be erased without losing
+   any information.
+
+   Also the structures and storage layout is optimized for use by the APT
+   and may not be suitable for all purposes. However it should be possible
+   to extend it with associate cache files that contain other information.
+
+   To keep memory use down the cache file only contains often used fields and
+   fields that are inexpensive to store, the Package file has a full list of
+   fields. Also the client may assume that all items are perfectly valid and
+   need not perform checks against their correctness. Removal of information
+   from the cache is possible, but blanks will be left in the file, and
+   unused strings will also be present. The recommended implementation is to
+   simply rebuild the cache each time any of the data files change. It is
+   possible to add a new package file to the cache without any negative side
+   effects.
+
+   <b>Note on Pointer access</b>
+   Clients should always use the CacheIterators classes for access to the
+   cache and the data in it. They also provide a simple STL-like method for
+   traversing the links of the datastructure.
+
+   Every item in every structure is stored as the index to that structure.
+   What this means is that once the files is mmaped every data access has to
+   go through a fix up stage to get a real memory pointer. This is done
+   by taking the index, multiplying it by the type size and then adding
+   it to the start address of the memory block. This sounds complex, but
+   in C it is a single array dereference. Because all items are aligned to
+   their size and indexes are stored as multiples of the size of the structure
+   the format is immediately portable to all possible architectures - BUT the
+   generated files are -NOT-.
+
+   This scheme allows code like this to be written:
+   <example>
+     void *Map = mmap(...);
+     Package *PkgList = (Package *)Map;
+     Header *Head = (Header *)Map;
+     char *Strings = (char *)Map;
+     cout << (Strings + PkgList[Head->HashTable[0]]->Name) << endl;
+   </example>
+   Notice the lack of casting or multiplication. The net result is to return
+   the name of the first package in the first hash bucket, without error
+   checks.
+
+   The generator uses allocation pools to group similarly sized structures in
+   large blocks to eliminate any alignment overhead. The generator also
+   assures that no structures overlap and all indexes are unique. Although
+   at first glance it may seem like there is the potential for two structures
+   to exist at the same point the generator never allows this to happen.
+   (See the discussion of free space pools)
+
+   See \ref pkgcachegen.h for more information about generating cache structures. */
+									/*}}}*/
+#ifndef PKGLIB_PKGCACHE_H
+#define PKGLIB_PKGCACHE_H
+#define __PKGLIB_IN_PKGCACHE_H
+#include <apt-pkg/macros.h>
+#include <apt-pkg/mmap.h>
+
+#include <cstddef>       // required for nullptr_t
+#include <string>
+#include <stdint.h>
+#include <time.h>
+
+#include <apt-pkg/string_view.h>
+
+
+// size of (potentially big) files like debs or the install size of them
+typedef uint64_t map_filesize_t;
+// storing file sizes of indexes, which are way below 4 GB for now
+typedef uint32_t map_filesize_small_t;
+// each package/group/dependency gets an id
+typedef uint32_t map_id_t;
+// some files get an id, too, but in far less absolute numbers
+typedef uint16_t map_fileid_t;
+
+// relative pointer from cache start
+template <typename T> class map_pointer {
+   uint32_t val;
+public:
+   map_pointer() noexcept : val(0) {}
+   map_pointer(std::nullptr_t) noexcept : val(0) {}
+   explicit map_pointer(uint32_t n) noexcept : val(n) {}
+   explicit operator uint32_t() noexcept { return val; }
+   explicit operator bool() noexcept { return val != 0; }
+};
+
+template<typename T> inline T *operator +(T *p, map_pointer<T> m) { return p + uint32_t(m); }
+template<typename T> inline bool operator ==(map_pointer<T> u, map_pointer<T> m) { return uint32_t(u) == uint32_t(m); }
+template<typename T> inline bool operator !=(map_pointer<T> u, map_pointer<T> m) { return uint32_t(u) != uint32_t(m); }
+template<typename T> inline bool operator <(map_pointer<T> u, map_pointer<T> m) { return uint32_t(u) < uint32_t(m); }
+template<typename T> inline bool operator >(map_pointer<T> u, map_pointer<T> m) { return uint32_t(u) > uint32_t(m); }
+template<typename T> inline uint32_t operator -(map_pointer<T> u, map_pointer<T> m) { return uint32_t(u) - uint32_t(m); }
+template<typename T> bool operator ==(map_pointer<T> m, std::nullptr_t) { return uint32_t(m) == 0; }
+template<typename T> bool operator !=(map_pointer<T> m, std::nullptr_t) { return uint32_t(m) != 0; }
+
+// same as the previous, but documented to be to a string item
+typedef map_pointer<char> map_stringitem_t;
+
+// we have only a small amount of flags for each item
+typedef uint8_t map_flags_t;
+typedef uint8_t map_number_t;
+
+class pkgVersioningSystem;
+class APT_PUBLIC pkgCache								/*{{{*/
+{
+   public:
+   // Cache element predeclarations
+   struct Header;
+   struct Group;
+   struct Package;
+   struct ReleaseFile;
+   struct PackageFile;
+   struct Version;
+   struct Description;
+   struct Provides;
+   struct Dependency;
+   struct DependencyData;
+   struct StringItem;
+   struct VerFile;
+   struct DescFile;
+   
+   // Iterators
+   template<typename Str, typename Itr> class Iterator;
+   class GrpIterator;
+   class PkgIterator;
+   class VerIterator;
+   class DescIterator;
+   class DepIterator;
+   class PrvIterator;
+   class RlsFileIterator;
+   class PkgFileIterator;
+   class VerFileIterator;
+   class DescFileIterator;
+   
+   class Namespace;
+   
+   // These are all the constants used in the cache structures
+
+   // WARNING - if you change these lists you must also edit
+   // the stringification in pkgcache.cc and also consider whether
+   // the cache file will become incompatible.
+   struct Dep
+   {
+      enum DepType {Depends=1,PreDepends=2,Suggests=3,Recommends=4,
+	 Conflicts=5,Replaces=6,Obsoletes=7,DpkgBreaks=8,Enhances=9};
+      /** \brief available compare operators
+
+          The lower 4 bits are used to indicate what operator is being specified and
+          the upper 4 bits are flags. OR indicates that the next package is
+          or'd with the current package. */
+      enum DepCompareOp {NoOp=0,LessEq=0x1,GreaterEq=0x2,Less=0x3,
+	 Greater=0x4,Equals=0x5,NotEquals=0x6,
+	 Or=0x10, /*!< or'ed with the next dependency */
+	 MultiArchImplicit=0x20, /*!< generated internally, not spelled out in the index */
+	 ArchSpecific=0x40 /*!< was decorated with an explicit architecture in index */
+      };
+   };
+   
+   struct State
+   {
+      /** \brief priority of a package version
+
+          Zero is used for unparsable or absent Priority fields. */
+      enum VerPriority {Required=1,Important=2,Standard=3,Optional=4,Extra=5};
+      enum PkgSelectedState {Unknown=0,Install=1,Hold=2,DeInstall=3,Purge=4};
+      enum PkgInstState {Ok=0,ReInstReq=1,HoldInst=2,HoldReInstReq=3};
+      enum PkgCurrentState {NotInstalled=0,UnPacked=1,HalfConfigured=2,
+	   HalfInstalled=4,ConfigFiles=5,Installed=6,
+           TriggersAwaited=7,TriggersPending=8};
+   };
+   
+   struct Flag
+   {
+      enum PkgFlags {Auto=(1<<0),Essential=(1<<3),Important=(1<<4)};
+      enum PkgFFlags {
+	 NotSource=(1<<0), /*!< packages can't be fetched from here, e.g. dpkg/status file */
+	 LocalSource=(1<<1), /*!< local sources can't and will not be verified by hashes */
+	 NoPackages=(1<<2), /*!< the file includes no package records itself, but additions like Translations */
+      };
+      enum ReleaseFileFlags {
+	 NotAutomatic=(1<<0), /*!< archive has a default pin of 1 */
+	 ButAutomaticUpgrades=(1<<1), /*!< (together with the previous) archive has a default pin of 100 */
+      };
+      enum ProvidesFlags {
+	 MultiArchImplicit=pkgCache::Dep::MultiArchImplicit, /*!< generated internally, not spelled out in the index */
+	 ArchSpecific=pkgCache::Dep::ArchSpecific /*!< was decorated with an explicit architecture in index */
+      };
+   };
+   
+   protected:
+   
+   // Memory mapped cache file
+   std::string CacheFile;
+   MMap &Map;
+   map_id_t sHash(APT::StringView S) const APT_PURE;
+   
+   public:
+   
+   // Pointers to the arrays of items
+   Header *HeaderP;
+   Group *GrpP;
+   Package *PkgP;
+   VerFile *VerFileP;
+   DescFile *DescFileP;
+   ReleaseFile *RlsFileP;
+   PackageFile *PkgFileP;
+   Version *VerP;
+   Description *DescP;
+   Provides *ProvideP;
+   Dependency *DepP;
+   DependencyData *DepDataP;
+   char *StrP;
+   void *reserved[12];
+
+   virtual bool ReMap(bool const &Errorchecks = true);
+   inline bool Sync() {return Map.Sync();}
+   inline MMap &GetMap() {return Map;}
+   inline void *DataEnd() {return ((unsigned char *)Map.Data()) + Map.Size();}
+      
+   // String hashing function (512 range)
+   inline map_id_t Hash(APT::StringView S) const {return sHash(S);}
+
+   APT_HIDDEN uint32_t CacheHash();
+
+   // Useful transformation things
+   static const char *Priority(unsigned char Priority);
+   
+   // Accessors
+   GrpIterator FindGrp(APT::StringView Name);
+   PkgIterator FindPkg(APT::StringView Name);
+   PkgIterator FindPkg(APT::StringView Name, APT::StringView Arch);
+
+   APT::StringView ViewString(map_stringitem_t idx) const
+   {
+      char *name = StrP + idx;
+      uint16_t len = *reinterpret_cast<const uint16_t*>(name - sizeof(uint16_t));
+      return APT::StringView(name, len);
+   }
+
+   Header &Head() {return *HeaderP;}
+   inline GrpIterator GrpBegin();
+   inline GrpIterator GrpEnd();
+   inline PkgIterator PkgBegin();
+   inline PkgIterator PkgEnd();
+   inline PkgFileIterator FileBegin();
+   inline PkgFileIterator FileEnd();
+   inline RlsFileIterator RlsFileBegin();
+   inline RlsFileIterator RlsFileEnd();
+
+   inline bool MultiArchCache() const { return MultiArchEnabled; }
+   inline char const * NativeArch();
+
+   // Make me a function
+   pkgVersioningSystem *VS;
+   
+   // Converters
+   static const char *CompTypeDeb(unsigned char Comp) APT_PURE;
+   static const char *CompType(unsigned char Comp) APT_PURE;
+   static const char *DepType(unsigned char Dep);
+
+   pkgCache(MMap *Map,bool DoMap = true);
+   virtual ~pkgCache();
+
+private:
+   void * const d;
+   bool MultiArchEnabled;
+};
+									/*}}}*/
+// Header structure							/*{{{*/
+struct pkgCache::Header
+{
+   /** \brief Signature information
+
+       This must contain the hex value 0x98FE76DC which is designed to
+       verify that the system loading the image has the same byte order
+       and byte size as the system saving the image */
+   uint32_t Signature;
+   /** These contain the version of the cache file */
+   map_number_t MajorVersion;
+   map_number_t MinorVersion;
+   /** \brief indicates if the cache should be erased
+
+       Dirty is true if the cache file was opened for reading, the client
+       expects to have written things to it and have not fully synced it.
+       The file should be erased and rebuilt if it is true. */
+   bool Dirty;
+
+   /** \brief Size of structure values
+
+       All *Sz variables contains the sizeof() that particular structure.
+       It is used as an extra consistency check on the structure of the file.
+
+       If any of the size values do not exactly match what the client expects
+       then the client should refuse the load the file. */
+   uint16_t HeaderSz;
+   map_number_t GroupSz;
+   map_number_t PackageSz;
+   map_number_t ReleaseFileSz;
+   map_number_t PackageFileSz;
+   map_number_t VersionSz;
+   map_number_t DescriptionSz;
+   map_number_t DependencySz;
+   map_number_t DependencyDataSz;
+   map_number_t ProvidesSz;
+   map_number_t VerFileSz;
+   map_number_t DescFileSz;
+
+   /** \brief Structure counts
+
+       These indicate the number of each structure contained in the cache.
+       PackageCount is especially useful for generating user state structures.
+       See Package::Id for more info. */
+   map_id_t GroupCount;
+   map_id_t PackageCount;
+   map_id_t VersionCount;
+   map_id_t DescriptionCount;
+   map_id_t DependsCount;
+   map_id_t DependsDataCount;
+   map_fileid_t ReleaseFileCount;
+   map_fileid_t PackageFileCount;
+   map_fileid_t VerFileCount;
+   map_fileid_t DescFileCount;
+   map_id_t ProvidesCount;
+
+   /** \brief index of the first PackageFile structure
+
+       The PackageFile structures are singly linked lists that represent
+       all package files that have been merged into the cache. */
+   map_pointer<PackageFile> FileList;
+   /** \brief index of the first ReleaseFile structure */
+   map_pointer<ReleaseFile> RlsFileList;
+
+   /** \brief String representing the version system used */
+   map_stringitem_t VerSysName;
+   /** \brief native architecture the cache was built against */
+   map_stringitem_t Architecture;
+   /** \brief all architectures the cache was built against */
+   map_stringitem_t Architectures;
+   /** \brief The maximum size of a raw entry from the original Package file */
+   map_filesize_t MaxVerFileSize;
+   /** \brief The maximum size of a raw entry from the original Translation file */
+   map_filesize_t MaxDescFileSize;
+
+   /** \brief The Pool structures manage the allocation pools that the generator uses
+
+       Start indicates the first byte of the pool, Count is the number of objects
+       remaining in the pool and ItemSize is the structure size (alignment factor)
+       of the pool. An ItemSize of 0 indicates the pool is empty. There should be
+       twice the number of pools as there are non-private structure types. The generator
+       stores this information so future additions can make use of any unused pool
+       blocks. */
+   DynamicMMap::Pool Pools[2 * 12];
+
+   /** \brief hash tables providing rapid group/package name lookup
+
+       Each group/package name is inserted into a hash table using pkgCache::Hash(const &string)
+       By iterating over each entry in the hash table it is possible to iterate over
+       the entire list of packages. Hash Collisions are handled with a singly linked
+       list of packages based at the hash item. The linked list contains only
+       packages that match the hashing function.
+       In the PkgHashTable is it possible that multiple packages have the same name -
+       these packages are stored as a sequence in the list.
+       The size of both tables is the same. */
+   uint32_t HashTableSize;
+   uint32_t GetHashTableSize() const { return HashTableSize; }
+   void SetHashTableSize(unsigned int const sz) { HashTableSize = sz; }
+   map_stringitem_t GetArchitectures() const { return Architectures; }
+   void SetArchitectures(map_stringitem_t const idx) { Architectures = idx; }
+
+#ifdef APT_COMPILING_APT
+   map_pointer<Group> * GrpHashTableP() const { return (map_pointer<Group>*) (this + 1); }
+   map_pointer<Package> * PkgHashTableP() const { return reinterpret_cast<map_pointer<Package> *>(GrpHashTableP() + GetHashTableSize()); }
+#endif
+
+   /** \brief Hash of the file (TODO: Rename) */
+   map_filesize_small_t CacheFileSize;
+
+   bool CheckSizes(Header &Against) const APT_PURE;
+   Header();
+};
+									/*}}}*/
+// Group structure							/*{{{*/
+/** \brief groups architecture depending packages together
+
+    On or more packages with the same name form a group, so we have
+    a simple way to access a package built for different architectures
+    Group exists in a singly linked list of group records starting at
+    the hash index of the name in the pkgCache::Header::GrpHashTable
+
+    They also act as a representation of source packages, allowing you to
+    iterate over all binaries produced by a source package.
+    */
+struct pkgCache::Group
+{
+   /** \brief Name of the group */
+   map_stringitem_t Name;
+
+   // Linked List
+   /** \brief Link to the first package which belongs to the group */
+   map_pointer<Package> FirstPackage;
+   /** \brief Link to the last package which belongs to the group */
+   map_pointer<Package> LastPackage;
+
+   /** \brief Link to the next Group */
+   map_pointer<Group> Next;
+   /** \brief unique sequel ID */
+   map_id_t ID;
+
+   /** \brief List of binary produces by source package with this name. */
+   map_pointer<Version> VersionsInSource;
+
+   /** \brief Private pointer */
+   map_pointer<void> d;
+};
+									/*}}}*/
+// Package structure							/*{{{*/
+/** \brief contains information for a single unique package
+
+    There can be any number of versions of a given package.
+    Package exists in a singly linked list of package records starting at
+    the hash index of the name in the pkgCache::Header::PkgHashTable
+
+    A package can be created for every architecture so package names are
+    not unique, but it is guaranteed that packages with the same name
+    are sequencel ordered in the list. Packages with the same name can be
+    accessed with the Group.
+*/
+struct pkgCache::Package
+{
+   /** \brief Architecture of the package */
+   map_stringitem_t Arch;
+   /** \brief Base of a singly linked list of versions
+
+       Each structure represents a unique version of the package.
+       The version structures contain links into PackageFile and the
+       original text file as well as detailed information about the size
+       and dependencies of the specific package. In this way multiple
+       versions of a package can be cleanly handled by the system.
+       Furthermore, this linked list is guaranteed to be sorted
+       from Highest version to lowest version with no duplicate entries. */
+   map_pointer<Version> VersionList;
+   /** \brief index to the installed version */
+   map_pointer<Version> CurrentVer;
+   /** \brief index of the group this package belongs to */
+   map_pointer<pkgCache::Group> Group;
+
+   // Linked list
+   /** \brief Link to the next package in the same bucket */
+   map_pointer<Package> NextPackage;
+   /** \brief List of all dependencies on this package */
+   map_pointer<Dependency> RevDepends;
+   /** \brief List of all "packages" this package provide */
+   map_pointer<Provides> ProvidesList;
+
+   // Install/Remove/Purge etc
+   /** \brief state that the user wishes the package to be in */
+   map_number_t SelectedState;     // What
+   /** \brief installation state of the package
+
+       This should be "ok" but in case the installation failed
+       it will be different.
+   */
+   map_number_t InstState;         // Flags
+   /** \brief indicates if the package is installed */
+   map_number_t CurrentState;      // State
+
+   /** \brief unique sequel ID
+
+       ID is a unique value from 0 to Header->PackageCount assigned by the generator.
+       This allows clients to create an array of size PackageCount and use it to store
+       state information for the package map. For instance the status file emitter uses
+       this to track which packages have been emitted already. */
+   map_id_t ID;
+   /** \brief some useful indicators of the package's state */
+   map_flags_t Flags;
+
+   /** \brief Private pointer */
+   map_pointer<void> d;
+};
+									/*}}}*/
+// Release File structure						/*{{{*/
+/** \brief stores information about the release files used to generate the cache
+
+    PackageFiles reference ReleaseFiles as we need to keep record of which
+    version belongs to which release e.g. for pinning. */
+struct pkgCache::ReleaseFile
+{
+   /** \brief physical disk file that this ReleaseFile represents */
+   map_stringitem_t FileName;
+   /** \brief the release information
+
+       Please see the files document for a description of what the
+       release information means. */
+   map_stringitem_t Archive;
+   map_stringitem_t Codename;
+   map_stringitem_t Version;
+   map_stringitem_t Origin;
+   map_stringitem_t Label;
+   /** \brief The site the index file was fetched from */
+   map_stringitem_t Site;
+
+   /** \brief Size of the file
+
+       Used together with the modification time as a
+       simple check to ensure that the Packages
+       file has not been altered since Cache generation. */
+   map_filesize_t Size;
+   /** \brief Modification time for the file */
+   time_t mtime;
+
+   /** @TODO document PackageFile::Flags */
+   map_flags_t Flags;
+
+   // Linked list
+   /** \brief Link to the next ReleaseFile in the Cache */
+   map_pointer<ReleaseFile> NextFile;
+   /** \brief unique sequel ID */
+   map_fileid_t ID;
+
+   /** \brief Private pointer */
+   map_pointer<void> d;
+};
+									/*}}}*/
+// Package File structure						/*{{{*/
+/** \brief stores information about the files used to generate the cache
+
+    Package files are referenced by Version structures to be able to know
+    after the generation still from which Packages file includes this Version
+    as we need this information later on e.g. for pinning. */
+struct pkgCache::PackageFile
+{
+   /** \brief physical disk file that this PackageFile represents */
+   map_stringitem_t FileName;
+   /** \brief the release information */
+   map_pointer<ReleaseFile> Release;
+
+   map_stringitem_t Component;
+   map_stringitem_t Architecture;
+
+   /** \brief indicates what sort of index file this is
+
+       @TODO enumerate at least the possible indexes */
+   map_stringitem_t IndexType;
+   /** \brief Size of the file
+
+       Used together with the modification time as a
+       simple check to ensure that the Packages
+       file has not been altered since Cache generation. */
+   map_filesize_t Size;
+   /** \brief Modification time for the file */
+   time_t mtime;
+
+   /** @TODO document PackageFile::Flags */
+   map_flags_t Flags;
+
+   // Linked list
+   /** \brief Link to the next PackageFile in the Cache */
+   map_pointer<PackageFile> NextFile;
+   /** \brief unique sequel ID */
+   map_fileid_t ID;
+
+   /** \brief Private pointer */
+   map_pointer<void> d;
+};
+									/*}}}*/
+// VerFile structure							/*{{{*/
+/** \brief associates a version with a PackageFile
+
+    This allows a full description of all Versions in all files
+    (and hence all sources) under consideration. */
+struct pkgCache::VerFile
+{
+   /** \brief index of the package file that this version was found in */
+   map_pointer<PackageFile> File;
+   /** \brief next step in the linked list */
+   map_pointer<VerFile> NextFile;
+   /** \brief position in the package file */
+   map_filesize_t Offset;         // File offset
+   /** @TODO document pkgCache::VerFile::Size */
+   map_filesize_t Size;
+};
+									/*}}}*/
+// DescFile structure							/*{{{*/
+/** \brief associates a description with a Translation file */
+struct pkgCache::DescFile
+{
+   /** \brief index of the file that this description was found in */
+   map_pointer<PackageFile> File;
+   /** \brief next step in the linked list */
+   map_pointer<DescFile> NextFile;
+   /** \brief position in the file */
+   map_filesize_t Offset;         // File offset
+   /** @TODO document pkgCache::DescFile::Size */
+   map_filesize_t Size;
+};
+									/*}}}*/
+// Version structure							/*{{{*/
+/** \brief information for a single version of a package
+
+    The version list is always sorted from highest version to lowest
+    version by the generator. Equal version numbers are either merged
+    or handled as separate versions based on the Hash value. */
+struct pkgCache::Version
+{
+   struct Extra;
+
+   /** \brief complete version string */
+   map_stringitem_t VerStr;
+   /** \brief section this version is filled in */
+   map_stringitem_t Section;
+   /** \brief source package name this version comes from
+      Always contains the name, even if it is the same as the binary name */
+   map_stringitem_t SourcePkgName;
+   /** \brief source version this version comes from
+      Always contains the version string, even if it is the same as the binary version */
+   map_stringitem_t SourceVerStr;
+
+   /** \brief Multi-Arch capabilities of a package version */
+   enum VerMultiArch { No = 0, /*!< is the default and doesn't trigger special behaviour */
+		       All = (1<<0), /*!< will cause that Ver.Arch() will report "all" */
+		       Foreign = (1<<1), /*!< can satisfy dependencies in another architecture */
+		       Same = (1<<2), /*!< can be co-installed with itself from other architectures */
+		       Allowed = (1<<3), /*!< other packages are allowed to depend on thispkg:any */
+		       AllForeign = All | Foreign,
+		       AllAllowed = All | Allowed };
+
+   /** \brief stores the MultiArch capabilities of this version
+
+       Flags used are defined in pkgCache::Version::VerMultiArch
+   */
+   map_number_t MultiArch;
+
+   /** \brief references all the PackageFile's that this version came from
+
+       FileList can be used to determine what distribution(s) the Version
+       applies to. If FileList is 0 then this is a blank version.
+       The structure should also have a 0 in all other fields excluding
+       pkgCache::Version::VerStr and Possibly pkgCache::Version::NextVer. */
+   map_pointer<VerFile> FileList;
+   /** \brief next (lower or equal) version in the linked list */
+   map_pointer<Version> NextVer;
+   /** \brief next description in the linked list */
+   map_pointer<Description> DescriptionList;
+   /** \brief base of the dependency list */
+   map_pointer<Dependency> DependsList;
+   /** \brief links to the owning package
+
+       This allows reverse dependencies to determine the package */
+   map_pointer<Package> ParentPkg;
+   /** \brief list of pkgCache::Provides */
+   map_pointer<Provides> ProvidesList;
+
+   /** \brief archive size for this version
+
+       For Debian this is the size of the .deb file. */
+   map_filesize_t Size; // These are the .deb size
+   /** \brief uncompressed size for this version */
+   map_filesize_t InstalledSize;
+   /** \brief characteristic value representing this version
+
+       No two packages in existence should have the same VerStr
+       and Hash with different contents. */
+   uint32_t Hash;
+   /** \brief unique sequel ID */
+   map_id_t ID;
+   /** \brief parsed priority value */
+   map_number_t Priority;
+   /** \brief next version in the source package (might be different binary) */
+   map_pointer<Version> NextInSource;
+
+   /** \brief Private pointer */
+   map_pointer<Extra> d;
+};
+
+#ifdef APT_COMPILING_APT
+/// \brief Extra information for packages. APT-internal use only.
+struct pkgCache::Version::Extra
+{
+   uint8_t PhasedUpdatePercentage;
+};
+#endif
+									/*}}}*/
+// Description structure						/*{{{*/
+/** \brief datamember of a linked list of available description for a version */
+struct pkgCache::Description
+{
+   /** \brief Language code of this description (translation)
+
+       If the value has a 0 length then this is read using the Package
+       file else the Translation-CODE file is used. */
+   map_stringitem_t language_code;
+   /** \brief MD5sum of the original description
+
+       Used to map Translations of a description to a version
+       and to check that the Translation is up-to-date. */
+   map_stringitem_t md5sum;
+
+   /** @TODO document pkgCache::Description::FileList */
+   map_pointer<DescFile> FileList;
+   /** \brief next translation for this description */
+   map_pointer<Description> NextDesc;
+   /** \brief the text is a description of this package */
+   map_pointer<Package> ParentPkg;
+
+   /** \brief unique sequel ID */
+   map_id_t ID;
+};
+									/*}}}*/
+// Dependency structure							/*{{{*/
+/** \brief information for a single dependency record
+
+    The records are split up like this to ease processing by the client.
+    The base of the linked list is pkgCache::Version::DependsList.
+    All forms of dependencies are recorded here including Depends,
+    Recommends, Suggests, Enhances, Conflicts, Replaces and Breaks. */
+struct pkgCache::DependencyData
+{
+   /** \brief string of the version the dependency is applied against */
+   map_stringitem_t Version;
+   /** \brief index of the package this depends applies to
+
+       The generator will - if the package does not already exist -
+       create a blank (no version records) package. */
+   map_pointer<pkgCache::Package> Package;
+
+   /** \brief Dependency type - Depends, Recommends, Conflicts, etc */
+   map_number_t Type;
+   /** \brief comparison operator specified on the depends line
+
+       If the high bit is set then it is a logical OR with the previous record. */
+   map_flags_t CompareOp;
+
+   map_pointer<DependencyData> NextData;
+};
+struct pkgCache::Dependency
+{
+   map_pointer<pkgCache::DependencyData> DependencyData;
+   /** \brief version of the package which has the depends */
+   map_pointer<Version> ParentVer;
+   /** \brief next reverse dependency of this package */
+   map_pointer<Dependency> NextRevDepends;
+   /** \brief next dependency of this version */
+   map_pointer<Dependency> NextDepends;
+
+   /** \brief unique sequel ID */
+   map_id_t ID;
+};
+									/*}}}*/
+// Provides structure							/*{{{*/
+/** \brief handles virtual packages
+
+    When a Provides: line is encountered a new provides record is added
+    associating the package with a virtual package name.
+    The provides structures are linked off the package structures.
+    This simplifies the analysis of dependencies and other aspects A provides
+    refers to a specific version of a specific package, not all versions need to
+    provide that provides.*/
+struct pkgCache::Provides
+{
+   /** \brief index of the package providing this */
+   map_pointer<Package> ParentPkg;
+   /** \brief index of the version this provide line applies to */
+   map_pointer<pkgCache::Version> Version;
+   /** \brief version in the provides line (if any)
+
+       This version allows dependencies to depend on specific versions of a
+       Provides, as well as allowing Provides to override existing packages. */
+   map_stringitem_t ProvideVersion;
+   map_flags_t Flags;
+   /** \brief next provides (based of package) */
+   map_pointer<Provides> NextProvides;
+   /** \brief next provides (based of version) */
+   map_pointer<Provides> NextPkgProv;
+};
+									/*}}}*/
+
+inline char const * pkgCache::NativeArch()
+	{ return StrP + HeaderP->Architecture; }
+
+#include <apt-pkg/cacheiterators.h>
+
+	inline pkgCache::GrpIterator pkgCache::GrpBegin()
+	{
+	   return GrpIterator(*this);
+	}
+	inline pkgCache::GrpIterator pkgCache::GrpEnd()
+	{
+	   return GrpIterator(*this, GrpP);}
+inline pkgCache::PkgIterator pkgCache::PkgBegin()
+       {return PkgIterator(*this);}
+inline pkgCache::PkgIterator pkgCache::PkgEnd()
+       {return PkgIterator(*this,PkgP);}
+inline pkgCache::PkgFileIterator pkgCache::FileBegin()
+       {return PkgFileIterator(*this,PkgFileP + HeaderP->FileList);}
+inline pkgCache::PkgFileIterator pkgCache::FileEnd()
+       {return PkgFileIterator(*this,PkgFileP);}
+inline pkgCache::RlsFileIterator pkgCache::RlsFileBegin()
+       {return RlsFileIterator(*this,RlsFileP + HeaderP->RlsFileList);}
+inline pkgCache::RlsFileIterator pkgCache::RlsFileEnd()
+       {return RlsFileIterator(*this,RlsFileP);}
+
+
+// Oh I wish for Real Name Space Support
+class pkgCache::Namespace						/*{{{*/
+{
+   public:
+   typedef pkgCache::GrpIterator GrpIterator;
+   typedef pkgCache::PkgIterator PkgIterator;
+   typedef pkgCache::VerIterator VerIterator;
+   typedef pkgCache::DescIterator DescIterator;
+   typedef pkgCache::DepIterator DepIterator;
+   typedef pkgCache::PrvIterator PrvIterator;
+   typedef pkgCache::RlsFileIterator RlsFileIterator;
+   typedef pkgCache::PkgFileIterator PkgFileIterator;
+   typedef pkgCache::VerFileIterator VerFileIterator;
+   typedef pkgCache::Version Version;
+   typedef pkgCache::Description Description;
+   typedef pkgCache::Package Package;
+   typedef pkgCache::Header Header;
+   typedef pkgCache::Dep Dep;
+   typedef pkgCache::Flag Flag;
+};
+									/*}}}*/
+#undef __PKGLIB_IN_PKGCACHE_H
+#endif
diff --git a/apt-pkg/pkgcachegen.cc b/apt-pkg/pkgcachegen.cc
new file mode 100644
index 0000000..807f3bf
--- /dev/null
+++ b/apt-pkg/pkgcachegen.cc
@@ -0,0 +1,1863 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Cache Generator - Generator for the cache structure.
+   
+   This builds the cache structure from the abstract package list parser. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/mmap.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/version.h>
+
+#include <algorithm>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <vector>
+#include <stddef.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+constexpr auto APT_CACHE_START_DEFAULT = 24 * 1024 * 1024;
+
+template<class T> using Dynamic = pkgCacheGenerator::Dynamic<T>;
+typedef std::vector<pkgIndexFile *>::iterator FileIterator;
+template <typename Iter> std::vector<Iter*> pkgCacheGenerator::Dynamic<Iter>::toReMap;
+
+static bool IsDuplicateDescription(pkgCache &Cache, pkgCache::DescIterator Desc,
+			    APT::StringView CurMd5, std::string const &CurLang);
+
+using std::string;
+using APT::StringView;
+
+// Convert an offset returned from e.g. DynamicMMap or ptr difference to
+// an uint32_t location without data loss.
+template <typename T>
+static inline uint32_t NarrowOffset(T ptr)
+{
+   uint32_t res = static_cast<uint32_t>(ptr);
+   if (unlikely(ptr < 0))
+      abort();
+   if (unlikely(static_cast<T>(res) != ptr))
+      abort();
+   return res;
+}
+
+// CacheGenerator::pkgCacheGenerator - Constructor			/*{{{*/
+// ---------------------------------------------------------------------
+/* We set the dirty flag and make sure that is written to the disk */
+pkgCacheGenerator::pkgCacheGenerator(DynamicMMap *pMap,OpProgress *Prog) :
+		    Map(*pMap), Cache(pMap,false), Progress(Prog),
+		     CurrentRlsFile(nullptr), CurrentFile(nullptr), d(nullptr)
+{
+}
+bool pkgCacheGenerator::Start()
+{
+   if (Map.Size() == 0)
+   {
+      // Setup the map interface..
+      Cache.HeaderP = (pkgCache::Header *)Map.Data();
+      _error->PushToStack();
+      Map.RawAllocate(sizeof(pkgCache::Header));
+      bool const newError = _error->PendingError();
+      _error->MergeWithStack();
+      if (newError)
+	 return false;
+      if (Map.Size() <= 0)
+	 return false;
+
+      Map.UsePools(*Cache.HeaderP->Pools,sizeof(Cache.HeaderP->Pools)/sizeof(Cache.HeaderP->Pools[0]));
+
+      // Starting header
+      *Cache.HeaderP = pkgCache::Header();
+
+      // make room for the hashtables for packages and groups
+      if (Map.RawAllocate(2 * (Cache.HeaderP->GetHashTableSize() * sizeof(map_pointer<void>))) == 0)
+	 return false;
+
+      map_stringitem_t const idxVerSysName = WriteStringInMap(_system->VS->Label);
+      if (unlikely(idxVerSysName == 0))
+	 return false;
+      map_stringitem_t const idxArchitecture = StoreString(MIXED, _config->Find("APT::Architecture"));
+      if (unlikely(idxArchitecture == 0))
+	 return false;
+      map_stringitem_t idxArchitectures;
+
+      std::vector<std::string> archs = APT::Configuration::getArchitectures();
+      if (archs.size() > 1)
+      {
+	 std::vector<std::string>::const_iterator a = archs.begin();
+	 std::string list = *a;
+	 for (++a; a != archs.end(); ++a)
+	    list.append(",").append(*a);
+	 idxArchitectures = WriteStringInMap(list);
+	 if (unlikely(idxArchitectures == 0))
+	    return false;
+      }
+      else
+	 idxArchitectures = idxArchitecture;
+
+      Cache.HeaderP = (pkgCache::Header *)Map.Data();
+      Cache.HeaderP->VerSysName = idxVerSysName;
+      Cache.HeaderP->Architecture = idxArchitecture;
+      Cache.HeaderP->SetArchitectures(idxArchitectures);
+
+      // Calculate the hash for the empty map, so ReMap does not fail
+      Cache.HeaderP->CacheFileSize = Cache.CacheHash();
+      Cache.ReMap();
+   }
+   else
+   {
+      // Map directly from the existing file
+      Cache.ReMap(); 
+      Map.UsePools(*Cache.HeaderP->Pools,sizeof(Cache.HeaderP->Pools)/sizeof(Cache.HeaderP->Pools[0]));
+      if (Cache.VS != _system->VS)
+	 return _error->Error(_("Cache has an incompatible versioning system"));
+   }
+
+   Cache.HeaderP->Dirty = true;
+   Map.Sync(0,sizeof(pkgCache::Header));
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::~pkgCacheGenerator - Destructor 			/*{{{*/
+// ---------------------------------------------------------------------
+/* We sync the data then unset the dirty flag in two steps so as to
+   advoid a problem during a crash */
+pkgCacheGenerator::~pkgCacheGenerator()
+{
+   if (_error->PendingError() == true || Map.validData() == false)
+      return;
+   if (Map.Sync() == false)
+      return;
+   
+   Cache.HeaderP->Dirty = false;
+   Cache.HeaderP->CacheFileSize = Cache.CacheHash();
+
+   if (_config->FindB("Debug::pkgCacheGen", false))
+      std::clog << "Produced cache with hash " << Cache.HeaderP->CacheFileSize << std::endl;
+   Map.Sync(0,sizeof(pkgCache::Header));
+}
+									/*}}}*/
+void pkgCacheGenerator::ReMap(void const * const oldMap, void * const newMap, size_t oldSize) {/*{{{*/
+   if (oldMap == newMap)
+      return;
+
+   // Prevent multiple remaps of the same iterator. If seen.insert(iterator)
+   // returns (something, true) the iterator was not yet seen and we can
+   // remap it.
+   std::unordered_set<void *> seen;
+
+   if (_config->FindB("Debug::pkgCacheGen", false))
+      std::clog << "Remapping from " << oldMap << " to " << newMap << std::endl;
+
+   Cache.ReMap(false);
+
+   if (CurrentFile != nullptr)
+      CurrentFile = static_cast<pkgCache::PackageFile *>(newMap) + (CurrentFile - static_cast<pkgCache::PackageFile const *>(oldMap));
+   if (CurrentRlsFile != nullptr)
+      CurrentRlsFile = static_cast<pkgCache::ReleaseFile *>(newMap) + (CurrentRlsFile - static_cast<pkgCache::ReleaseFile const *>(oldMap));
+
+#define APT_REMAP(TYPE) \
+   for (auto * const i : Dynamic<TYPE>::toReMap) \
+      if (seen.insert(i).second) \
+	 i->ReMap(oldMap, newMap)
+   APT_REMAP(pkgCache::GrpIterator);
+   APT_REMAP(pkgCache::PkgIterator);
+   APT_REMAP(pkgCache::VerIterator);
+   APT_REMAP(pkgCache::DepIterator);
+   APT_REMAP(pkgCache::DescIterator);
+   APT_REMAP(pkgCache::PrvIterator);
+   APT_REMAP(pkgCache::PkgFileIterator);
+   APT_REMAP(pkgCache::RlsFileIterator);
+#undef APT_REMAP
+
+   for (APT::StringView* ViewP : Dynamic<APT::StringView>::toReMap) {
+      if (std::get<1>(seen.insert(ViewP)) == false)
+	 continue;
+      // Ignore views outside of the cache.
+      if (ViewP->data() < static_cast<const char*>(oldMap)
+	 || ViewP->data() > static_cast<const char*>(oldMap) + oldSize)
+	 continue;
+      const char *data = ViewP->data() + (static_cast<const char*>(newMap) - static_cast<const char*>(oldMap));
+      *ViewP = StringView(data , ViewP->size());
+   }
+}									/*}}}*/
+// CacheGenerator::WriteStringInMap					/*{{{*/
+map_stringitem_t pkgCacheGenerator::WriteStringInMap(const char *String,
+					const unsigned long &Len) {
+   size_t oldSize = Map.Size();
+   void const * const oldMap = Map.Data();
+   map_stringitem_t const index{NarrowOffset(Map.WriteString(String, Len))};
+   if (index != 0)
+      ReMap(oldMap, Map.Data(), oldSize);
+   return index;
+}
+									/*}}}*/
+// CacheGenerator::WriteStringInMap					/*{{{*/
+map_stringitem_t pkgCacheGenerator::WriteStringInMap(const char *String) {
+   size_t oldSize = Map.Size();
+   void const * const oldMap = Map.Data();
+   map_stringitem_t const index{NarrowOffset(Map.WriteString(String))};
+   if (index != 0)
+      ReMap(oldMap, Map.Data(), oldSize);
+   return index;
+}
+									/*}}}*/
+uint32_t pkgCacheGenerator::AllocateInMap(const unsigned long &size) {/*{{{*/
+   size_t oldSize = Map.Size();
+   void const * const oldMap = Map.Data();
+   auto index = Map.Allocate(size);
+   if (index != 0)
+      ReMap(oldMap, Map.Data(), oldSize);
+   if (index != static_cast<uint32_t>(index))
+      abort();					// Internal error
+   return static_cast<uint32_t>(index);
+}
+									/*}}}*/
+// CacheGenerator::MergeList - Merge the package list			/*{{{*/
+// ---------------------------------------------------------------------
+/* This provides the generation of the entries in the cache. Each loop
+   goes through a single package record from the underlying parse engine. */
+bool pkgCacheGenerator::MergeList(ListParser &List,
+				  pkgCache::VerIterator *OutVer)
+{
+   List.Owner = this;
+
+   unsigned int Counter = 0;
+   while (List.Step() == true)
+   {
+      string const PackageName = List.Package();
+      if (PackageName.empty() == true)
+	 return false;
+
+      Counter++;
+      if (Counter % 100 == 0 && Progress != 0)
+	 Progress->Progress(List.Offset());
+
+      APT::StringView Arch = List.Architecture();
+      Dynamic<APT::StringView> DynArch(Arch);
+      APT::StringView Version = List.Version();
+      Dynamic<APT::StringView> DynVersion(Version);
+      if (Version.empty() == true && Arch.empty() == true)
+      {
+	 // package descriptions
+	 if (MergeListGroup(List, PackageName) == false)
+	    return false;
+	 continue;
+      }
+
+      // Get a pointer to the package structure
+      pkgCache::PkgIterator Pkg;
+      Dynamic<pkgCache::PkgIterator> DynPkg(Pkg);
+      if (NewPackage(Pkg, PackageName, Arch) == false)
+	 // TRANSLATOR: The first placeholder is a package name,
+	 // the other two should be copied verbatim as they include debug info
+	 return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			      PackageName.c_str(), "NewPackage", 1);
+
+
+      if (Version.empty() == true)
+      {
+	 if (MergeListPackage(List, Pkg) == false)
+	    return false;
+      }
+      else
+      {
+	 if (MergeListVersion(List, Pkg, Version, OutVer) == false)
+	    return false;
+      }
+
+      if (OutVer != 0)
+	 return true;
+   }
+
+   if (Cache.HeaderP->PackageCount >= std::numeric_limits<map_id_t>::max())
+      return _error->Error(_("Wow, you exceeded the number of package "
+			     "names this APT is capable of."));
+   if (Cache.HeaderP->VersionCount >= std::numeric_limits<map_id_t>::max())
+      return _error->Error(_("Wow, you exceeded the number of versions "
+			     "this APT is capable of."));
+   if (Cache.HeaderP->DescriptionCount >= std::numeric_limits<map_id_t>::max())
+      return _error->Error(_("Wow, you exceeded the number of descriptions "
+			     "this APT is capable of."));
+   if (Cache.HeaderP->DependsCount >= std::numeric_limits<map_id_t>::max())
+      return _error->Error(_("Wow, you exceeded the number of dependencies "
+			     "this APT is capable of."));
+
+   return true;
+}
+// CacheGenerator::MergeListGroup					/*{{{*/
+bool pkgCacheGenerator::MergeListGroup(ListParser &List, std::string const &GrpName)
+{
+   pkgCache::GrpIterator Grp = Cache.FindGrp(GrpName);
+   // a group has no data on it's own, only packages have it but these
+   // stanzas like this come from Translation- files to add descriptions,
+   // but without a version we don't need a description for it…
+   if (Grp.end() == true)
+      return true;
+   Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+
+   pkgCache::PkgIterator Pkg;
+   Dynamic<pkgCache::PkgIterator> DynPkg(Pkg);
+   for (Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
+      if (MergeListPackage(List, Pkg) == false)
+	 return false;
+
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::MergeListPackage					/*{{{*/
+bool pkgCacheGenerator::MergeListPackage(ListParser &List, pkgCache::PkgIterator &Pkg)
+{
+   // we first process the package, then the descriptions
+   // (for deb this package processing is in fact a no-op)
+   pkgCache::VerIterator Ver(Cache);
+   Dynamic<pkgCache::VerIterator> DynVer(Ver);
+   if (List.UsePackage(Pkg, Ver) == false)
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "UsePackage", 1);
+
+   // Find the right version to write the description
+   StringView CurMd5 = List.Description_md5();
+   std::vector<std::string> availDesc = List.AvailableDescriptionLanguages();
+   for (Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
+   {
+      pkgCache::DescIterator VerDesc = Ver.DescriptionList();
+
+      // a version can only have one md5 describing it
+      if (VerDesc.end() == true || Cache.ViewString(VerDesc->md5sum) != CurMd5)
+	 continue;
+
+      map_stringitem_t md5idx = VerDesc->md5sum;
+      for (std::vector<std::string>::const_iterator CurLang = availDesc.begin(); CurLang != availDesc.end(); ++CurLang)
+      {
+	 // don't add a new description if we have one for the given
+	 // md5 && language
+	 if (IsDuplicateDescription(Cache, VerDesc, CurMd5, *CurLang) == true)
+	    continue;
+
+	 AddNewDescription(List, Ver, *CurLang, CurMd5, md5idx);
+      }
+
+      // we can stop here as all "same" versions will share the description
+      break;
+   }
+
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::MergeListVersion					/*{{{*/
+bool pkgCacheGenerator::MergeListVersion(ListParser &List, pkgCache::PkgIterator &Pkg,
+					 APT::StringView const &Version, pkgCache::VerIterator* &OutVer)
+{
+   pkgCache::VerIterator Ver = Pkg.VersionList();
+   Dynamic<pkgCache::VerIterator> DynVer(Ver);
+   map_pointer<pkgCache::Version> *LastVer = &Pkg->VersionList;
+   void const * oldMap = Map.Data();
+
+   auto Hash = List.VersionHash();
+   if (Ver.end() == false)
+   {
+      /* We know the list is sorted so we use that fact in the search.
+         Insertion of new versions is done with correct sorting */
+      int Res = 1;
+      for (; Ver.end() == false; LastVer = &Ver->NextVer, ++Ver)
+      {
+	 char const * const VerStr = Ver.VerStr();
+	 Res = Cache.VS->DoCmpVersion(Version.data(), Version.data() + Version.length(),
+	       VerStr, VerStr + strlen(VerStr));
+	 // Version is higher as current version - insert here
+	 if (Res > 0)
+	    break;
+	 // Versionstrings are equal - is hash also equal?
+	 if (Res == 0)
+	 {
+	    if (List.SameVersion(Hash, Ver) == true)
+	       break;
+	    // sort (volatile) sources above not-sources like the status file
+	    if (CurrentFile == nullptr || (CurrentFile->Flags & pkgCache::Flag::NotSource) == 0)
+	    {
+	       auto VF = Ver.FileList();
+	       for (; VF.end() == false; ++VF)
+		  if (VF.File().Flagged(pkgCache::Flag::NotSource) == false)
+		     break;
+	       if (VF.end() == true)
+		  break;
+	    }
+	 }
+	 // proceed with the next till we have either the right
+	 // or we found another version (which will be lower)
+      }
+
+      /* We already have a version for this item, record that we saw it */
+      if (Res == 0 && Ver.end() == false && Ver->Hash == Hash)
+      {
+	 if (List.UsePackage(Pkg,Ver) == false)
+	    return _error->Error(_("Error occurred while processing %s (%s%d)"),
+				 Pkg.Name(), "UsePackage", 2);
+
+	 if (NewFileVer(Ver,List) == false)
+	    return _error->Error(_("Error occurred while processing %s (%s%d)"),
+				 Pkg.Name(), "NewFileVer", 1);
+
+	 // Read only a single record and return
+	 if (OutVer != 0)
+	 {
+	    *OutVer = Ver;
+	    return true;
+	 }
+
+	 return true;
+      }
+   }
+
+   // Add a new version
+   map_pointer<pkgCache::Version> const verindex = NewVersion(Ver, Version, Pkg.MapPointer(), Hash, *LastVer);
+   if (unlikely(verindex == 0))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "NewVersion", 1);
+
+   if (oldMap != Map.Data())
+	 LastVer = static_cast<map_pointer<pkgCache::Version> *>(Map.Data()) + (LastVer - static_cast<map_pointer<pkgCache::Version> const *>(oldMap));
+   *LastVer = verindex;
+
+   if (unlikely(List.NewVersion(Ver) == false))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "NewVersion", 2);
+
+   if (unlikely(List.UsePackage(Pkg,Ver) == false))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "UsePackage", 3);
+
+   if (unlikely(NewFileVer(Ver,List) == false))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "NewFileVer", 2);
+
+   pkgCache::GrpIterator Grp = Pkg.Group();
+   Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+
+   /* If it is the first version of this package we need to add implicit
+      Multi-Arch dependencies to all other package versions in the group now -
+      otherwise we just add them for this new version */
+   if (Pkg.VersionList()->NextVer == 0)
+   {
+      pkgCache::PkgIterator P = Grp.PackageList();
+      Dynamic<pkgCache::PkgIterator> DynP(P);
+      for (; P.end() != true; P = Grp.NextPkg(P))
+      {
+	 if (P->ID == Pkg->ID)
+	    continue;
+	 pkgCache::VerIterator V = P.VersionList();
+	 Dynamic<pkgCache::VerIterator> DynV(V);
+	 for (; V.end() != true; ++V)
+	    if (unlikely(AddImplicitDepends(V, Pkg) == false))
+	       return _error->Error(_("Error occurred while processing %s (%s%d)"),
+				    Pkg.Name(), "AddImplicitDepends", 1);
+      }
+   }
+   if (unlikely(AddImplicitDepends(Grp, Pkg, Ver) == false))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+			   Pkg.Name(), "AddImplicitDepends", 2);
+
+   // Read only a single record and return
+   if (OutVer != 0)
+   {
+      *OutVer = Ver;
+      return true;
+   }
+
+   /* Record the Description(s) based on their master md5sum */
+   StringView CurMd5 = List.Description_md5();
+
+   /* Before we add a new description we first search in the group for
+      a version with a description of the same MD5 - if so we reuse this
+      description group instead of creating our own for this version */
+   for (pkgCache::PkgIterator P = Grp.PackageList();
+	P.end() == false; P = Grp.NextPkg(P))
+   {
+      for (pkgCache::VerIterator V = P.VersionList();
+	   V.end() == false; ++V)
+      {
+	 if (V->DescriptionList == 0 || Cache.ViewString(V.DescriptionList()->md5sum) != CurMd5)
+	    continue;
+	 Ver->DescriptionList = V->DescriptionList;
+      }
+   }
+
+   // We haven't found reusable descriptions, so add the first description(s)
+   map_stringitem_t md5idx = Ver->DescriptionList == 0 ? 0 : Ver.DescriptionList()->md5sum;
+   std::vector<std::string> availDesc = List.AvailableDescriptionLanguages();
+   for (std::vector<std::string>::const_iterator CurLang = availDesc.begin(); CurLang != availDesc.end(); ++CurLang)
+      if (AddNewDescription(List, Ver, *CurLang, CurMd5, md5idx) == false)
+	 return false;
+   return true;
+}
+									/*}}}*/
+bool pkgCacheGenerator::AddNewDescription(ListParser &List, pkgCache::VerIterator &Ver, std::string const &lang, APT::StringView CurMd5, map_stringitem_t &md5idx) /*{{{*/
+{
+   pkgCache::DescIterator Desc;
+   Dynamic<pkgCache::DescIterator> DynDesc(Desc);
+
+   map_pointer<pkgCache::Description> const descindex = NewDescription(Desc, lang, CurMd5, md5idx);
+   if (unlikely(descindex == 0))
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+	    Ver.ParentPkg().Name(), "NewDescription", 1);
+
+   md5idx = Desc->md5sum;
+   Desc->ParentPkg = Ver.ParentPkg().MapPointer();
+
+   // we add at the end, so that the start is constant as we need
+   // that to be able to efficiently share these lists
+   pkgCache::DescIterator VerDesc = Ver.DescriptionList(); // old value might be invalid after ReMap
+   for (;VerDesc.end() == false && VerDesc->NextDesc != 0; ++VerDesc);
+   map_pointer<pkgCache::Description> * const LastNextDesc = (VerDesc.end() == true) ? &Ver->DescriptionList : &VerDesc->NextDesc;
+   *LastNextDesc = descindex;
+
+   if (NewFileDesc(Desc,List) == false)
+      return _error->Error(_("Error occurred while processing %s (%s%d)"),
+	    Ver.ParentPkg().Name(), "NewFileDesc", 1);
+
+   return true;
+}
+									/*}}}*/
+									/*}}}*/
+// CacheGenerator::NewGroup - Add a new group				/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a new group structure and adds it to the hash table */
+bool pkgCacheGenerator::NewGroup(pkgCache::GrpIterator &Grp, StringView Name)
+{
+   Dynamic<StringView> DName(Name);
+   Grp = Cache.FindGrp(Name);
+   if (Grp.end() == false)
+      return true;
+
+   // Get a structure
+   auto const Group = AllocateInMap<pkgCache::Group>();
+   if (unlikely(Group == 0))
+      return false;
+
+   map_stringitem_t const idxName = WriteStringInMap(Name);
+   if (unlikely(idxName == 0))
+      return false;
+
+   Grp = pkgCache::GrpIterator(Cache, Cache.GrpP + Group);
+   Grp->Name = idxName;
+
+   // Insert it into the hash table
+   unsigned long const Hash = Cache.Hash(Name);
+   map_pointer<pkgCache::Group> *insertAt = &Cache.HeaderP->GrpHashTableP()[Hash];
+
+   while (*insertAt != 0 && StringViewCompareFast(Name, Cache.ViewString((Cache.GrpP + *insertAt)->Name)) > 0)
+      insertAt = &(Cache.GrpP + *insertAt)->Next;
+   Grp->Next = *insertAt;
+   *insertAt = Group;
+
+   Grp->ID = Cache.HeaderP->GroupCount++;
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::NewPackage - Add a new package			/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a new package structure and adds it to the hash table */
+bool pkgCacheGenerator::NewPackage(pkgCache::PkgIterator &Pkg, StringView Name,
+					StringView Arch) {
+   pkgCache::GrpIterator Grp;
+   Dynamic<StringView> DName(Name);
+   Dynamic<StringView> DArch(Arch);
+   Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+   if (unlikely(NewGroup(Grp, Name) == false))
+      return false;
+
+   Pkg = Grp.FindPkg(Arch);
+      if (Pkg.end() == false)
+	 return true;
+
+   // Get a structure
+   auto const Package = AllocateInMap<pkgCache::Package>();
+   if (unlikely(Package == 0))
+      return false;
+   Pkg = pkgCache::PkgIterator(Cache,Cache.PkgP + Package);
+
+   // Set the name, arch and the ID
+   Pkg->Group = Grp.MapPointer();
+   // all is mapped to the native architecture
+   map_stringitem_t const idxArch = (Arch == "all") ? Cache.HeaderP->Architecture : StoreString(MIXED, Arch);
+   if (unlikely(idxArch == 0))
+      return false;
+   Pkg->Arch = idxArch;
+   Pkg->ID = Cache.HeaderP->PackageCount++;
+
+   // Insert the package into our package list
+   if (Grp->FirstPackage == 0) // the group is new
+   {
+      Grp->FirstPackage = Package;
+      // Insert it into the hash table
+      map_id_t const Hash = Cache.Hash(Name);
+      map_pointer<pkgCache::Package> *insertAt = &Cache.HeaderP->PkgHashTableP()[Hash];
+      while (*insertAt != 0 && StringViewCompareFast(Name, Cache.ViewString((Cache.GrpP + (Cache.PkgP + *insertAt)->Group)->Name)) > 0)
+	 insertAt = &(Cache.PkgP + *insertAt)->NextPackage;
+      Pkg->NextPackage = *insertAt;
+      *insertAt = Package;
+   }
+   else // Group the Packages together
+   {
+      // if sibling is provided by another package, this one is too
+      {
+	 pkgCache::PkgIterator const M = Grp.FindPreferredPkg(false); // native or any foreign pkg will do
+	 if (M.end() == false) {
+	    pkgCache::PrvIterator Prv;
+	    pkgCache::VerIterator Ver;
+	    Dynamic<pkgCache::PrvIterator> DynPrv(Prv);
+	    Dynamic<pkgCache::VerIterator> DynVer(Ver);
+	    for (Prv = M.ProvidesList(); Prv.end() == false; ++Prv)
+	    {
+	       if ((Prv->Flags & pkgCache::Flag::ArchSpecific) != 0)
+		  continue;
+	       Ver = Prv.OwnerVer();
+	       if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign &&
+		   (Prv->Flags & pkgCache::Flag::MultiArchImplicit) == 0)
+	       {
+		  if (APT::Configuration::checkArchitecture(Ver.ParentPkg().Arch()) == false)
+		     continue;
+		  if (NewProvides(Ver, Pkg, Prv->ProvideVersion, Prv->Flags) == false)
+		     return false;
+	       }
+	    }
+	 }
+      }
+      // let M-A:foreign package siblings provide this package
+      {
+	 pkgCache::PkgIterator P;
+	 pkgCache::VerIterator Ver;
+	 Dynamic<pkgCache::PkgIterator> DynP(P);
+	 Dynamic<pkgCache::VerIterator> DynVer(Ver);
+
+	 for (P = Grp.PackageList(); P.end() == false;  P = Grp.NextPkg(P))
+	 {
+	    if (APT::Configuration::checkArchitecture(P.Arch()) == false)
+	       continue;
+	    for (Ver = P.VersionList(); Ver.end() == false; ++Ver)
+	       if ((Ver->MultiArch & pkgCache::Version::Foreign) == pkgCache::Version::Foreign)
+		  if (NewProvides(Ver, Pkg, Ver->VerStr, pkgCache::Flag::MultiArchImplicit) == false)
+		     return false;
+	 }
+      }
+      // and negative dependencies, don't forget negative dependencies
+      {
+	 pkgCache::PkgIterator const M = Grp.FindPreferredPkg(false);
+	 if (M.end() == false) {
+	    pkgCache::DepIterator Dep;
+	    Dynamic<pkgCache::DepIterator> DynDep(Dep);
+	    for (Dep = M.RevDependsList(); Dep.end() == false; ++Dep)
+	    {
+	       if ((Dep->CompareOp & (pkgCache::Dep::ArchSpecific | pkgCache::Dep::MultiArchImplicit)) != 0)
+		  continue;
+	       if (Dep->Type != pkgCache::Dep::DpkgBreaks && Dep->Type != pkgCache::Dep::Conflicts &&
+		     Dep->Type != pkgCache::Dep::Replaces)
+		  continue;
+	       pkgCache::VerIterator Ver = Dep.ParentVer();
+	       Dynamic<pkgCache::VerIterator> DynVer(Ver);
+	       map_pointer<pkgCache::Dependency> * unused = NULL;
+	       if (NewDepends(Pkg, Ver, Dep->Version, Dep->CompareOp, Dep->Type, unused) == false)
+		  return false;
+	    }
+	 }
+      }
+
+      // this package is the new last package
+      pkgCache::PkgIterator LastPkg(Cache, Cache.PkgP + Grp->LastPackage);
+      Pkg->NextPackage = LastPkg->NextPackage;
+      LastPkg->NextPackage = Package;
+   }
+   Grp->LastPackage = Package;
+
+   // lazy-create foo (of amd64) provides foo:amd64 at the time we first need it
+   if (Arch == "any")
+   {
+      size_t const found = Name.rfind(':');
+      StringView ArchA = Name.substr(found + 1);
+      if (ArchA != "any")
+      {
+	 // ArchA is used inside the loop which might remap (NameA is not used)
+	 Dynamic<StringView> DynArchA(ArchA);
+	 StringView NameA = Name.substr(0, found);
+	 pkgCache::PkgIterator PkgA = Cache.FindPkg(NameA, ArchA);
+	 Dynamic<pkgCache::PkgIterator> DynPkgA(PkgA);
+	 if (PkgA.end())
+	 {
+	    Dynamic<StringView> DynNameA(NameA);
+	    if (NewPackage(PkgA, NameA, ArchA) == false)
+	       return false;
+	 }
+	 if (unlikely(PkgA.end()))
+	    return _error->Fatal("NewPackage was successful for %s:%s,"
+		  "but the package doesn't exist anyhow!",
+		  NameA.to_string().c_str(), ArchA.to_string().c_str());
+	 else
+	 {
+	    pkgCache::PrvIterator Prv = PkgA.ProvidesList();
+	    for (; Prv.end() == false; ++Prv)
+	    {
+	       if (Prv.IsMultiArchImplicit())
+		  continue;
+	       pkgCache::VerIterator V = Prv.OwnerVer();
+	       if (ArchA != V.ParentPkg().Arch())
+		  continue;
+	       if (NewProvides(V, Pkg, V->VerStr, pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific) == false)
+		  return false;
+	    }
+	    pkgCache::VerIterator V = PkgA.VersionList();
+	    Dynamic<pkgCache::VerIterator> DynV(V);
+	    for (; V.end() == false; ++V)
+	    {
+	       if (NewProvides(V, Pkg, V->VerStr, pkgCache::Flag::MultiArchImplicit | pkgCache::Flag::ArchSpecific) == false)
+		  return false;
+	    }
+	 }
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::AddImplicitDepends					/*{{{*/
+bool pkgCacheGenerator::AddImplicitDepends(pkgCache::GrpIterator &G,
+					   pkgCache::PkgIterator &P,
+					   pkgCache::VerIterator &V)
+{
+   APT::StringView Arch = P.Arch() == NULL ? "" : P.Arch();
+   Dynamic<APT::StringView> DynArch(Arch);
+   map_pointer<pkgCache::Dependency> *OldDepLast = NULL;
+   /* MultiArch handling introduces a lot of implicit Dependencies:
+      - MultiArch: same → Co-Installable if they have the same version
+      - All others conflict with all other group members */
+   bool const coInstall = ((V->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same);
+   pkgCache::PkgIterator D = G.PackageList();
+   Dynamic<pkgCache::PkgIterator> DynD(D);
+   map_stringitem_t const VerStrIdx = V->VerStr;
+   for (; D.end() != true; D = G.NextPkg(D))
+   {
+      if (Arch == D.Arch() || D->VersionList == 0)
+	 continue;
+      /* We allow only one installed arch at the time
+	 per group, therefore each group member conflicts
+	 with all other group members */
+      if (coInstall == true)
+      {
+	 // Replaces: ${self}:other ( << ${binary:Version})
+	 NewDepends(D, V, VerStrIdx,
+		    pkgCache::Dep::Less | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::Replaces,
+		    OldDepLast);
+	 // Breaks: ${self}:other (!= ${binary:Version})
+	 NewDepends(D, V, VerStrIdx,
+		    pkgCache::Dep::NotEquals | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::DpkgBreaks,
+		    OldDepLast);
+      } else {
+	 // Conflicts: ${self}:other
+	 NewDepends(D, V, 0,
+		    pkgCache::Dep::NoOp | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::Conflicts,
+		    OldDepLast);
+      }
+   }
+   return true;
+}
+bool pkgCacheGenerator::AddImplicitDepends(pkgCache::VerIterator &V,
+					   pkgCache::PkgIterator &D)
+{
+   /* MultiArch handling introduces a lot of implicit Dependencies:
+      - MultiArch: same → Co-Installable if they have the same version
+      - All others conflict with all other group members */
+   map_pointer<pkgCache::Dependency> *OldDepLast = NULL;
+   bool const coInstall = ((V->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same);
+   if (coInstall == true)
+   {
+      map_stringitem_t const VerStrIdx = V->VerStr;
+      // Replaces: ${self}:other ( << ${binary:Version})
+      NewDepends(D, V, VerStrIdx,
+		 pkgCache::Dep::Less | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::Replaces,
+		 OldDepLast);
+      // Breaks: ${self}:other (!= ${binary:Version})
+      NewDepends(D, V, VerStrIdx,
+		 pkgCache::Dep::NotEquals | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::DpkgBreaks,
+		 OldDepLast);
+   } else {
+      // Conflicts: ${self}:other
+      NewDepends(D, V, 0,
+		 pkgCache::Dep::NoOp | pkgCache::Dep::MultiArchImplicit, pkgCache::Dep::Conflicts,
+		 OldDepLast);
+   }
+   return true;
+}
+
+									/*}}}*/
+// CacheGenerator::NewFileVer - Create a new File<->Version association	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheGenerator::NewFileVer(pkgCache::VerIterator &Ver,
+				   ListParser &List)
+{
+   if (CurrentFile == nullptr)
+      return true;
+   
+   // Get a structure
+   auto const VerFile = AllocateInMap<pkgCache::VerFile>();
+   if (VerFile == 0)
+      return false;
+   
+   pkgCache::VerFileIterator VF(Cache,Cache.VerFileP + VerFile);
+   VF->File = map_pointer<pkgCache::PackageFile>{NarrowOffset(CurrentFile - Cache.PkgFileP)};
+   
+   // Link it to the end of the list
+   map_pointer<pkgCache::VerFile> *Last = &Ver->FileList;
+   for (pkgCache::VerFileIterator V = Ver.FileList(); V.end() == false; ++V)
+      Last = &V->NextFile;
+   VF->NextFile = *Last;
+   *Last = VF.MapPointer();
+   
+   VF->Offset = List.Offset();
+   VF->Size = List.Size();
+   if (Cache.HeaderP->MaxVerFileSize < VF->Size)
+      Cache.HeaderP->MaxVerFileSize = VF->Size;
+   Cache.HeaderP->VerFileCount++;
+   
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::NewVersion - Create a new Version 			/*{{{*/
+// ---------------------------------------------------------------------
+/* This puts a version structure in the linked list */
+map_pointer<pkgCache::Version> pkgCacheGenerator::NewVersion(pkgCache::VerIterator &Ver,
+					    APT::StringView const &VerStr,
+					    map_pointer<pkgCache::Package> const ParentPkg,
+					    uint32_t Hash,
+					    map_pointer<pkgCache::Version> const Next)
+{
+   // Get a structure
+   auto const Version = AllocateInMap<pkgCache::Version>();
+   if (Version == 0)
+      return 0;
+   
+   // Fill it in
+   Ver = pkgCache::VerIterator(Cache,Cache.VerP + Version);
+   auto d = AllocateInMap<pkgCache::Version::Extra>(); // sequence point so Ver can be moved if needed
+   Ver->d = d;
+   if (not Ver.PhasedUpdatePercentage(100))
+      abort();
+
+   //Dynamic<pkgCache::VerIterator> DynV(Ver); // caller MergeListVersion already takes care of it
+   Ver->NextVer = Next;
+   Ver->ParentPkg = ParentPkg;
+   Ver->Hash = Hash;
+   Ver->ID = Cache.HeaderP->VersionCount++;
+
+   // try to find the version string in the group for reuse
+   pkgCache::PkgIterator Pkg = Ver.ParentPkg();
+   pkgCache::GrpIterator Grp = Pkg.Group();
+   if (Pkg.end() == false && Grp.end() == false)
+   {
+      for (pkgCache::PkgIterator P = Grp.PackageList(); P.end() == false; P = Grp.NextPkg(P))
+      {
+	 if (Pkg == P)
+	    continue;
+	 for (pkgCache::VerIterator V = P.VersionList(); V.end() == false; ++V)
+	 {
+	    int const cmp = strncmp(V.VerStr(), VerStr.data(), VerStr.length());
+	    if (cmp == 0 && V.VerStr()[VerStr.length()] == '\0')
+	    {
+	       Ver->VerStr = V->VerStr;
+	       return Version;
+	    }
+	    else if (cmp < 0)
+	       break;
+	 }
+      }
+   }
+   // haven't found the version string, so create
+   map_stringitem_t const idxVerStr = StoreString(VERSIONNUMBER, VerStr);
+   if (unlikely(idxVerStr == 0))
+      return 0;
+   Ver->VerStr = idxVerStr;
+   return Version;
+}
+									/*}}}*/
+// CacheGenerator::NewFileDesc - Create a new File<->Desc association	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgCacheGenerator::NewFileDesc(pkgCache::DescIterator &Desc,
+				   ListParser &List)
+{
+   if (CurrentFile == nullptr)
+      return true;
+   
+   // Get a structure
+   auto const DescFile = AllocateInMap<pkgCache::DescFile>();
+   if (DescFile == 0)
+      return false;
+
+   pkgCache::DescFileIterator DF(Cache,Cache.DescFileP + DescFile);
+   DF->File = map_pointer<pkgCache::PackageFile>{NarrowOffset(CurrentFile - Cache.PkgFileP)};
+
+   // Link it to the end of the list
+   map_pointer<pkgCache::DescFile> *Last = &Desc->FileList;
+   for (pkgCache::DescFileIterator D = Desc.FileList(); D.end() == false; ++D)
+      Last = &D->NextFile;
+
+   DF->NextFile = *Last;
+   *Last = DF.MapPointer();
+   
+   DF->Offset = List.Offset();
+   DF->Size = List.Size();
+   if (Cache.HeaderP->MaxDescFileSize < DF->Size)
+      Cache.HeaderP->MaxDescFileSize = DF->Size;
+   Cache.HeaderP->DescFileCount++;
+   
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::NewDescription - Create a new Description		/*{{{*/
+// ---------------------------------------------------------------------
+/* This puts a description structure in the linked list */
+map_pointer<pkgCache::Description> pkgCacheGenerator::NewDescription(pkgCache::DescIterator &Desc,
+					    const string &Lang,
+					    APT::StringView md5sum,
+					    map_stringitem_t const idxmd5str)
+{
+   // Get a structure
+   auto const Description = AllocateInMap<pkgCache::Description>();
+   if (Description == 0)
+      return 0;
+
+   // Fill it in
+   Desc = pkgCache::DescIterator(Cache,Cache.DescP + Description);
+   Desc->ID = Cache.HeaderP->DescriptionCount++;
+   map_stringitem_t const idxlanguage_code = StoreString(MIXED, Lang);
+   if (unlikely(idxlanguage_code == 0))
+      return 0;
+   Desc->language_code = idxlanguage_code;
+
+   if (idxmd5str != 0)
+      Desc->md5sum = idxmd5str;
+   else
+   {
+      map_stringitem_t const idxmd5sum = WriteStringInMap(md5sum);
+      if (unlikely(idxmd5sum == 0))
+	 return 0;
+      Desc->md5sum = idxmd5sum;
+   }
+
+   return Description;
+}
+									/*}}}*/
+// CacheGenerator::NewDepends - Create a dependency element		/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a dependency element in the tree. It is linked to the
+   version and to the package that it is pointing to. */
+bool pkgCacheGenerator::NewDepends(pkgCache::PkgIterator &Pkg,
+				   pkgCache::VerIterator &Ver,
+				   map_stringitem_t const Version,
+				   uint8_t const Op,
+				   uint8_t const Type,
+				   map_pointer<pkgCache::Dependency> * &OldDepLast)
+{
+   void const * const oldMap = Map.Data();
+   // Get a structure
+   auto const Dependency = AllocateInMap<pkgCache::Dependency>();
+   if (unlikely(Dependency == 0))
+      return false;
+
+   bool isDuplicate = false;
+   map_pointer<pkgCache::DependencyData> DependencyData = 0;
+   map_pointer<pkgCache::DependencyData> PreviousData = 0;
+   if (Pkg->RevDepends != 0)
+   {
+      pkgCache::Dependency const * const L = Cache.DepP + Pkg->RevDepends;
+      DependencyData = L->DependencyData;
+      do {
+	 pkgCache::DependencyData const * const D = Cache.DepDataP + DependencyData;
+	 if (Version > D->Version)
+	    break;
+	 if (D->Version == Version && D->Type == Type && D->CompareOp == Op)
+	 {
+	    isDuplicate = true;
+	    break;
+	 }
+	 PreviousData = DependencyData;
+	 DependencyData = D->NextData;
+      } while (DependencyData != 0);
+   }
+
+   if (isDuplicate == false)
+   {
+      DependencyData = AllocateInMap<pkgCache::DependencyData>();
+      if (unlikely(DependencyData == 0))
+        return false;
+   }
+
+   pkgCache::Dependency * Link = Cache.DepP + Dependency;
+   Link->ParentVer = Ver.MapPointer();
+   Link->DependencyData = DependencyData;
+   Link->ID = Cache.HeaderP->DependsCount++;
+
+   pkgCache::DepIterator Dep(Cache, Link);
+   if (isDuplicate == false)
+   {
+      Dep->Type = Type;
+      Dep->CompareOp = Op;
+      Dep->Version = Version;
+      Dep->Package = Pkg.MapPointer();
+      ++Cache.HeaderP->DependsDataCount;
+      if (PreviousData != 0)
+      {
+	 pkgCache::DependencyData * const D = Cache.DepDataP + PreviousData;
+	 Dep->NextData = D->NextData;
+	 D->NextData = DependencyData;
+      }
+      else if (Pkg->RevDepends != 0)
+      {
+	 pkgCache::Dependency const * const D = Cache.DepP + Pkg->RevDepends;
+	 Dep->NextData = D->DependencyData;
+      }
+   }
+
+   if (isDuplicate == true || PreviousData != 0)
+   {
+      pkgCache::Dependency * const L = Cache.DepP + Pkg->RevDepends;
+      Link->NextRevDepends = L->NextRevDepends;
+      L->NextRevDepends = Dependency;
+   }
+   else
+   {
+      Link->NextRevDepends = Pkg->RevDepends;
+      Pkg->RevDepends = Dependency;
+   }
+
+
+   // Do we know where to link the Dependency to?
+   if (OldDepLast == NULL)
+   {
+      OldDepLast = &Ver->DependsList;
+      for (pkgCache::DepIterator D = Ver.DependsList(); D.end() == false; ++D)
+	 OldDepLast = &D->NextDepends;
+   } else if (oldMap != Map.Data())
+      OldDepLast = static_cast<map_pointer<pkgCache::Dependency> *>(Map.Data()) + (OldDepLast - static_cast<map_pointer<pkgCache::Dependency> const *>(oldMap));
+
+   Dep->NextDepends = *OldDepLast;
+   *OldDepLast = Dependency;
+   OldDepLast = &Dep->NextDepends;
+   return true;
+}
+									/*}}}*/
+// ListParser::NewDepends - Create the environment for a new dependency	/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a Group and the Package to link this dependency to if
+   needed and handles also the caching of the old endpoint */
+bool pkgCacheListParser::NewDepends(pkgCache::VerIterator &Ver,
+					       StringView PackageName,
+					       StringView Arch,
+					       StringView Version,
+					       uint8_t const Op,
+					       uint8_t const Type)
+{
+   pkgCache::GrpIterator Grp;
+   Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+   Dynamic<StringView> DynPackageName(PackageName);
+   Dynamic<StringView> DynArch(Arch);
+   Dynamic<StringView> DynVersion(Version);
+   if (unlikely(Owner->NewGroup(Grp, PackageName) == false))
+      return false;
+
+   map_stringitem_t idxVersion = 0;
+   if (Version.empty() == false)
+   {
+      int const CmpOp = Op & 0x0F;
+      // =-deps are used (79:1) for lockstep on same-source packages (e.g. data-packages)
+      if (CmpOp == pkgCache::Dep::Equals && Version == Ver.VerStr())
+	 idxVersion = Ver->VerStr;
+
+      if (idxVersion == 0)
+      {
+	 idxVersion = StoreString(pkgCacheGenerator::VERSIONNUMBER, Version);
+	 if (unlikely(idxVersion == 0))
+	    return false;
+      }
+   }
+
+   bool const isNegative = (Type == pkgCache::Dep::DpkgBreaks ||
+	 Type == pkgCache::Dep::Conflicts ||
+	 Type == pkgCache::Dep::Replaces);
+
+   pkgCache::PkgIterator Pkg;
+   Dynamic<pkgCache::PkgIterator> DynPkg(Pkg);
+   if (isNegative == false || (Op & pkgCache::Dep::ArchSpecific) == pkgCache::Dep::ArchSpecific || Grp->FirstPackage == 0)
+   {
+      // Locate the target package
+      Pkg = Grp.FindPkg(Arch);
+      if (Pkg.end() == true) {
+	 if (unlikely(Owner->NewPackage(Pkg, PackageName, Arch) == false))
+	    return false;
+      }
+
+      /* Caching the old end point speeds up generation substantially */
+      if (OldDepVer != Ver) {
+	 OldDepLast = NULL;
+	 OldDepVer = Ver;
+      }
+
+      return Owner->NewDepends(Pkg, Ver, idxVersion, Op, Type, OldDepLast);
+   }
+   else
+   {
+      /* Caching the old end point speeds up generation substantially */
+      if (OldDepVer != Ver) {
+	 OldDepLast = NULL;
+	 OldDepVer = Ver;
+      }
+
+      for (Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
+      {
+	 if (Owner->NewDepends(Pkg, Ver, idxVersion, Op, Type, OldDepLast) == false)
+	       return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// ListParser::NewProvides - Create a Provides element			/*{{{*/
+bool pkgCacheListParser::NewProvides(pkgCache::VerIterator &Ver,
+						StringView PkgName,
+						StringView PkgArch,
+						StringView Version,
+						uint8_t const Flags)
+{
+   pkgCache const &Cache = Owner->Cache;
+   Dynamic<StringView> DynPkgName(PkgName);
+   Dynamic<StringView> DynArch(PkgArch);
+   Dynamic<StringView> DynVersion(Version);
+
+   // We do not add self referencing provides
+   if (Ver.ParentPkg().Name() == PkgName && (PkgArch == Ver.ParentPkg().Arch() ||
+	(PkgArch == "all" && strcmp((Cache.StrP + Cache.HeaderP->Architecture), Ver.ParentPkg().Arch()) == 0)) &&
+	 (Version.empty() || Version == Ver.VerStr()))
+      return true;
+
+   // Locate the target package
+   pkgCache::PkgIterator Pkg;
+   Dynamic<pkgCache::PkgIterator> DynPkg(Pkg);
+   if (unlikely(Owner->NewPackage(Pkg,PkgName, PkgArch) == false))
+      return false;
+
+   map_stringitem_t idxProvideVersion = 0;
+   if (Version.empty() == false) {
+      idxProvideVersion = StoreString(pkgCacheGenerator::VERSIONNUMBER, Version);
+      if (unlikely(idxProvideVersion == 0))
+	 return false;
+   }
+   return Owner->NewProvides(Ver, Pkg, idxProvideVersion, Flags);
+}
+bool pkgCacheGenerator::NewProvides(pkgCache::VerIterator &Ver,
+				    pkgCache::PkgIterator &Pkg,
+				    map_stringitem_t const ProvideVersion,
+				    uint8_t const Flags)
+{
+   // Get a structure
+   auto const Provides = AllocateInMap<pkgCache::Provides>();
+   if (unlikely(Provides == 0))
+      return false;
+   ++Cache.HeaderP->ProvidesCount;
+
+   // Fill it in
+   pkgCache::PrvIterator Prv(Cache,Cache.ProvideP + Provides,Cache.PkgP);
+   Prv->Version = Ver.MapPointer();
+   Prv->ProvideVersion = ProvideVersion;
+   Prv->Flags = Flags;
+   Prv->NextPkgProv = Ver->ProvidesList;
+   Ver->ProvidesList = Prv.MapPointer();
+
+   // Link it to the package
+   Prv->ParentPkg = Pkg.MapPointer();
+   Prv->NextProvides = Pkg->ProvidesList;
+   Pkg->ProvidesList = Prv.MapPointer();
+   return true;
+}
+									/*}}}*/
+// ListParser::NewProvidesAllArch - add provides for all architectures	/*{{{*/
+bool pkgCacheListParser::NewProvidesAllArch(pkgCache::VerIterator &Ver, StringView Package,
+				StringView Version, uint8_t const Flags) {
+   pkgCache &Cache = Owner->Cache;
+   pkgCache::GrpIterator Grp = Cache.FindGrp(Package);
+   Dynamic<pkgCache::GrpIterator> DynGrp(Grp);
+   Dynamic<StringView> DynPackage(Package);
+   Dynamic<StringView> DynVersion(Version);
+
+   if (Grp.end() == true || Grp->FirstPackage == 0)
+      return NewProvides(Ver, Package, Cache.NativeArch(), Version, Flags);
+   else
+   {
+      map_stringitem_t idxProvideVersion = 0;
+      if (Version.empty() == false) {
+	 idxProvideVersion = StoreString(pkgCacheGenerator::VERSIONNUMBER, Version);
+	 if (unlikely(idxProvideVersion == 0))
+	    return false;
+      }
+
+      bool const isImplicit = (Flags & pkgCache::Flag::MultiArchImplicit) == pkgCache::Flag::MultiArchImplicit;
+      bool const isArchSpecific = (Flags & pkgCache::Flag::ArchSpecific) == pkgCache::Flag::ArchSpecific;
+      pkgCache::PkgIterator OwnerPkg = Ver.ParentPkg();
+      Dynamic<pkgCache::PkgIterator> DynOwnerPkg(OwnerPkg);
+      pkgCache::PkgIterator Pkg;
+      Dynamic<pkgCache::PkgIterator> DynPkg(Pkg);
+      for (Pkg = Grp.PackageList(); Pkg.end() == false; Pkg = Grp.NextPkg(Pkg))
+      {
+	 if (isImplicit && OwnerPkg == Pkg)
+	    continue;
+	 if (isArchSpecific == false && APT::Configuration::checkArchitecture(OwnerPkg.Arch()) == false)
+	    continue;
+	 if (Owner->NewProvides(Ver, Pkg, idxProvideVersion, Flags) == false)
+	    return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+bool pkgCacheListParser::SameVersion(uint32_t Hash,		/*{{{*/
+      pkgCache::VerIterator const &Ver)
+{
+   return Hash == Ver->Hash;
+}
+									/*}}}*/
+// CacheGenerator::SelectReleaseFile - Select the current release file the indexes belong to	/*{{{*/
+bool pkgCacheGenerator::SelectReleaseFile(const string &File,const string &Site,
+				   unsigned long Flags)
+{
+   CurrentRlsFile = nullptr;
+   if (File.empty() && Site.empty())
+      return true;
+
+   // Get some space for the structure
+   auto const idxFile = AllocateInMap<pkgCache::ReleaseFile>();
+   if (unlikely(idxFile == 0))
+      return false;
+   CurrentRlsFile = Cache.RlsFileP + idxFile;
+
+   // Fill it in
+   map_stringitem_t const idxFileName = WriteStringInMap(File);
+   map_stringitem_t const idxSite = StoreString(MIXED, Site);
+   if (unlikely(idxFileName == 0 || idxSite == 0))
+      return false;
+   CurrentRlsFile->FileName = idxFileName;
+   CurrentRlsFile->Site = idxSite;
+   CurrentRlsFile->NextFile = Cache.HeaderP->RlsFileList;
+   CurrentRlsFile->Flags = Flags;
+   CurrentRlsFile->ID = Cache.HeaderP->ReleaseFileCount;
+   RlsFileName = File;
+   Cache.HeaderP->RlsFileList = map_pointer<pkgCache::ReleaseFile>{NarrowOffset(CurrentRlsFile - Cache.RlsFileP)};
+   Cache.HeaderP->ReleaseFileCount++;
+
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::SelectFile - Select the current file being parsed	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to select which file is to be associated with all newly
+   added versions. The caller is responsible for setting the IMS fields. */
+bool pkgCacheGenerator::SelectFile(std::string const &File,
+				   pkgIndexFile const &Index,
+				   std::string const &Architecture,
+				   std::string const &Component,
+				   unsigned long const Flags)
+{
+   CurrentFile = nullptr;
+   // Get some space for the structure
+   auto const idxFile = AllocateInMap<pkgCache::PackageFile>();
+   if (unlikely(idxFile == 0))
+      return false;
+   CurrentFile = Cache.PkgFileP + idxFile;
+
+   // Fill it in
+   map_stringitem_t const idxFileName = WriteStringInMap(File);
+   if (unlikely(idxFileName == 0))
+      return false;
+   CurrentFile->FileName = idxFileName;
+   CurrentFile->NextFile = Cache.HeaderP->FileList;
+   CurrentFile->ID = Cache.HeaderP->PackageFileCount;
+   map_stringitem_t const idxIndexType = StoreString(MIXED, Index.GetType()->Label);
+   if (unlikely(idxIndexType == 0))
+      return false;
+   CurrentFile->IndexType = idxIndexType;
+   if (Architecture.empty())
+      CurrentFile->Architecture = 0;
+   else
+   {
+      map_stringitem_t const arch = StoreString(pkgCacheGenerator::MIXED, Architecture);
+      if (unlikely(arch == 0))
+	 return false;
+      CurrentFile->Architecture = arch;
+   }
+   map_stringitem_t const component = StoreString(pkgCacheGenerator::MIXED, Component);
+   if (unlikely(component == 0))
+      return false;
+   CurrentFile->Component = component;
+   CurrentFile->Flags = Flags;
+   if (CurrentRlsFile != nullptr)
+      CurrentFile->Release = map_pointer<pkgCache::ReleaseFile>{NarrowOffset(CurrentRlsFile - Cache.RlsFileP)};
+   else
+      CurrentFile->Release = 0;
+   PkgFileName = File;
+   Cache.HeaderP->FileList = map_pointer<pkgCache::PackageFile>{NarrowOffset(CurrentFile - Cache.PkgFileP)};
+   Cache.HeaderP->PackageFileCount++;
+
+   if (Progress != 0)
+      Progress->SubProgress(Index.Size());
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::WriteUniqueString - Insert a unique string		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to create handles to strings. Given the same text it
+   always returns the same number */
+map_stringitem_t pkgCacheGenerator::StoreString(enum StringType const type, const char *S,
+						 unsigned int Size)
+{
+   auto strings = &strMixed;
+   switch(type) {
+      case MIXED: strings = &strMixed; break;
+      case VERSIONNUMBER: strings = &strVersions; break;
+      case SECTION: strings = &strSections; break;
+      default: _error->Fatal("Unknown enum type used for string storage of '%.*s'", Size, S); return 0;
+   }
+
+   auto const item = strings->find({S, Size, nullptr, 0});
+   if (item != strings->end())
+      return item->item;
+
+   map_stringitem_t const idxString = WriteStringInMap(S,Size);
+   strings->insert({nullptr, Size, this, idxString});
+   return idxString;
+}
+									/*}}}*/
+// CheckValidity - Check that a cache is up-to-date			/*{{{*/
+// ---------------------------------------------------------------------
+/* This just verifies that each file in the list of index files exists,
+   has matching attributes with the cache and the cache does not have
+   any extra files. */
+class APT_HIDDEN ScopedErrorRevert {
+public:
+   ScopedErrorRevert() { _error->PushToStack(); }
+   ~ScopedErrorRevert() { _error->RevertToStack(); }
+};
+
+static bool CheckValidity(FileFd &CacheFile, std::string const &CacheFileName,
+                          pkgSourceList &List,
+                          FileIterator const Start,
+                          FileIterator const End,
+                          MMap **OutMap = 0,
+			  pkgCache **OutCache = 0)
+{
+   if (CacheFileName.empty())
+      return false;
+   ScopedErrorRevert ser;
+
+   bool const Debug = _config->FindB("Debug::pkgCacheGen", false);
+   // No file, certainly invalid
+   if (CacheFile.Open(CacheFileName, FileFd::ReadOnly, FileFd::None) == false)
+   {
+      if (Debug == true)
+	 std::clog << "CacheFile " << CacheFileName << " doesn't exist" << std::endl;
+      return false;
+   }
+
+   if (_config->FindI("APT::Cache-Start", 0) == 0)
+   {
+      auto const size = CacheFile.FileSize();
+      if (std::numeric_limits<int>::max() >= size && size > APT_CACHE_START_DEFAULT)
+	 _config->Set("APT::Cache-Start", size);
+   }
+
+   if (List.GetLastModifiedTime() > CacheFile.ModificationTime())
+   {
+      if (Debug == true)
+	 std::clog << "sources.list is newer than the cache" << std::endl;
+      return false;
+   }
+
+   // Map it
+   std::unique_ptr<MMap> Map(new MMap(CacheFile,0));
+   if (unlikely(Map->validData()) == false)
+      return false;
+   std::unique_ptr<pkgCache> CacheP(new pkgCache(Map.get()));
+   pkgCache &Cache = *CacheP.get();
+   if (_error->PendingError() || Map->Size() == 0)
+   {
+      if (Debug == true)
+	 std::clog << "Errors are pending or Map is empty() for " << CacheFileName << std::endl;
+      return false;
+   }
+
+   std::unique_ptr<bool[]> RlsVisited(new bool[Cache.HeaderP->ReleaseFileCount]);
+   memset(RlsVisited.get(),0,sizeof(RlsVisited[0])*Cache.HeaderP->ReleaseFileCount);
+   std::vector<pkgIndexFile *> Files;
+   for (pkgSourceList::const_iterator i = List.begin(); i != List.end(); ++i)
+   {
+      if (Debug == true)
+	 std::clog << "Checking RlsFile " << (*i)->Describe() << ": ";
+      pkgCache::RlsFileIterator const RlsFile = (*i)->FindInCache(Cache, true);
+      if (RlsFile.end() == true)
+      {
+	 if (Debug == true)
+	    std::clog << "FindInCache returned end-Pointer" << std::endl;
+	 return false;
+      }
+
+      RlsVisited[RlsFile->ID] = true;
+      if (Debug == true)
+	 std::clog << "with ID " << RlsFile->ID << " is valid" << std::endl;
+
+      std::vector <pkgIndexFile *> const * const Indexes = (*i)->GetIndexFiles();
+      std::copy_if(Indexes->begin(), Indexes->end(), std::back_inserter(Files),
+	    [](pkgIndexFile const * const I) { return I->HasPackages(); });
+   }
+   for (unsigned I = 0; I != Cache.HeaderP->ReleaseFileCount; ++I)
+      if (RlsVisited[I] == false)
+      {
+	 if (Debug == true)
+	    std::clog << "RlsFile with ID" << I << " wasn't visited" << std::endl;
+	 return false;
+      }
+
+   std::copy(Start, End, std::back_inserter(Files));
+
+   /* Now we check every index file, see if it is in the cache,
+      verify the IMS data and check that it is on the disk too.. */
+   std::unique_ptr<bool[]> Visited(new bool[Cache.HeaderP->PackageFileCount]);
+   memset(Visited.get(),0,sizeof(Visited[0])*Cache.HeaderP->PackageFileCount);
+   for (std::vector<pkgIndexFile *>::const_reverse_iterator PkgFile = Files.rbegin(); PkgFile != Files.rend(); ++PkgFile)
+   {
+      if (Debug == true)
+	 std::clog << "Checking PkgFile " << (*PkgFile)->Describe() << ": ";
+      if ((*PkgFile)->Exists() == false)
+      {
+         if (Debug == true)
+	    std::clog << "file doesn't exist" << std::endl;
+	 continue;
+      }
+
+      // FindInCache is also expected to do an IMS check.
+      pkgCache::PkgFileIterator File = (*PkgFile)->FindInCache(Cache);
+      if (File.end() == true)
+      {
+	 if (Debug == true)
+	    std::clog << "FindInCache returned end-Pointer" << std::endl;
+	 return false;
+      }
+
+      Visited[File->ID] = true;
+      if (Debug == true)
+	 std::clog << "with ID " << File->ID << " is valid" << std::endl;
+   }
+
+   for (unsigned I = 0; I != Cache.HeaderP->PackageFileCount; I++)
+      if (Visited[I] == false)
+      {
+	 if (Debug == true)
+	    std::clog << "PkgFile with ID" << I << " wasn't visited" << std::endl;
+	 return false;
+      }
+
+   if (_error->PendingError() == true)
+   {
+      if (Debug == true)
+      {
+	 std::clog << "Validity failed because of pending errors:" << std::endl;
+	 _error->DumpErrors(std::clog, GlobalError::DEBUG, false);
+      }
+      return false;
+   }
+
+   if (OutMap != 0)
+      *OutMap = Map.release();
+   if (OutCache != 0)
+      *OutCache = CacheP.release();
+   return true;
+}
+									/*}}}*/
+// ComputeSize - Compute the total size of a bunch of files		/*{{{*/
+// ---------------------------------------------------------------------
+/* Size is kind of an abstract notion that is only used for the progress
+   meter */
+static map_filesize_t ComputeSize(pkgSourceList const * const List, FileIterator Start,FileIterator End)
+{
+   map_filesize_t TotalSize = 0;
+   if (List !=  NULL)
+   {
+      for (pkgSourceList::const_iterator i = List->begin(); i != List->end(); ++i)
+      {
+	 std::vector <pkgIndexFile *> *Indexes = (*i)->GetIndexFiles();
+	 for (std::vector<pkgIndexFile *>::const_iterator j = Indexes->begin(); j != Indexes->end(); ++j)
+	    if ((*j)->HasPackages() == true)
+	       TotalSize += (*j)->Size();
+      }
+   }
+
+   for (; Start < End; ++Start)
+   {
+      if ((*Start)->HasPackages() == false)
+	 continue;
+      TotalSize += (*Start)->Size();
+   }
+   return TotalSize;
+}
+									/*}}}*/
+// BuildCache - Merge the list of index files into the cache		/*{{{*/
+static bool BuildCache(pkgCacheGenerator &Gen,
+		       OpProgress * const Progress,
+		       map_filesize_t &CurrentSize,map_filesize_t TotalSize,
+		       pkgSourceList const * const List,
+		       FileIterator const Start, FileIterator const End)
+{
+   bool mergeFailure = false;
+
+   auto const indexFileMerge = [&](pkgIndexFile * const I) {
+      if (I->HasPackages() == false || mergeFailure)
+	 return;
+
+      if (I->Exists() == false)
+	 return;
+
+      if (I->FindInCache(Gen.GetCache()).end() == false)
+      {
+	 _error->Warning("Duplicate sources.list entry %s",
+	       I->Describe().c_str());
+	 return;
+      }
+
+      map_filesize_t const Size = I->Size();
+      if (Progress != NULL)
+	 Progress->OverallProgress(CurrentSize, TotalSize, Size, _("Reading package lists"));
+      CurrentSize += Size;
+
+      if (I->Merge(Gen,Progress) == false)
+	 mergeFailure = true;
+   };
+
+   if (List !=  NULL)
+   {
+      for (pkgSourceList::const_iterator i = List->begin(); i != List->end(); ++i)
+      {
+	 if ((*i)->FindInCache(Gen.GetCache(), false).end() == false)
+	 {
+	    _error->Warning("Duplicate sources.list entry %s",
+		  (*i)->Describe().c_str());
+	    continue;
+	 }
+
+	 if ((*i)->Merge(Gen, Progress) == false)
+	    return false;
+
+	 std::vector <pkgIndexFile *> *Indexes = (*i)->GetIndexFiles();
+	 if (Indexes != NULL)
+	    std::for_each(Indexes->begin(), Indexes->end(), indexFileMerge);
+	 if (mergeFailure)
+	    return false;
+      }
+   }
+
+   if (Start != End)
+   {
+      Gen.SelectReleaseFile("", "");
+      std::for_each(Start, End, indexFileMerge);
+      if (mergeFailure)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::MakeStatusCache - Construct the status cache		/*{{{*/
+// ---------------------------------------------------------------------
+/* This makes sure that the status cache (the cache that has all 
+   index files from the sources list and all local ones) is ready
+   to be mmaped. If OutMap is not zero then a MMap object representing
+   the cache will be stored there. This is pretty much mandatory if you
+   are using AllowMem. AllowMem lets the function be run as non-root
+   where it builds the cache 'fast' into a memory buffer. */
+static DynamicMMap* CreateDynamicMMap(FileFd * const CacheF, unsigned long Flags)
+{
+   map_filesize_t const MapStart = _config->FindI("APT::Cache-Start", APT_CACHE_START_DEFAULT);
+   map_filesize_t const MapGrow = _config->FindI("APT::Cache-Grow", 1*1024*1024);
+   map_filesize_t const MapLimit = _config->FindI("APT::Cache-Limit", 0);
+   Flags |= MMap::Moveable;
+   if (_config->FindB("APT::Cache-Fallback", false) == true)
+      Flags |= MMap::Fallback;
+   if (CacheF != NULL)
+      return new DynamicMMap(*CacheF, Flags, MapStart, MapGrow, MapLimit);
+   else
+      return new DynamicMMap(Flags, MapStart, MapGrow, MapLimit);
+}
+static bool writeBackMMapToFile(pkgCacheGenerator * const Gen, DynamicMMap * const Map,
+      std::string const &FileName)
+{
+   FileFd SCacheF(FileName, FileFd::WriteAtomic);
+   if (SCacheF.IsOpen() == false || SCacheF.Failed())
+      return false;
+
+   fchmod(SCacheF.Fd(),0644);
+
+   // Write out the main data
+   if (SCacheF.Write(Map->Data(),Map->Size()) == false)
+      return _error->Error(_("IO Error saving source cache"));
+
+   // Write out the proper header
+   Gen->GetCache().HeaderP->Dirty = false;
+   Gen->GetCache().HeaderP->CacheFileSize = Gen->GetCache().CacheHash();
+   if (SCacheF.Seek(0) == false ||
+	 SCacheF.Write(Map->Data(),sizeof(*Gen->GetCache().HeaderP)) == false)
+      return _error->Error(_("IO Error saving source cache"));
+   Gen->GetCache().HeaderP->Dirty = true;
+   return true;
+}
+static bool loadBackMMapFromFile(std::unique_ptr<pkgCacheGenerator> &Gen,
+      std::unique_ptr<DynamicMMap> &Map, OpProgress * const Progress, FileFd &CacheF)
+{
+   Map.reset(CreateDynamicMMap(NULL, 0));
+   if (unlikely(Map->validData()) == false)
+      return false;
+   if (CacheF.IsOpen() == false || CacheF.Seek(0) == false || CacheF.Failed())
+      return false;
+   _error->PushToStack();
+   uint32_t const alloc = Map->RawAllocate(CacheF.Size());
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+   if (alloc == 0 && newError)
+      return false;
+   if (CacheF.Read((unsigned char *)Map->Data() + alloc, CacheF.Size()) == false)
+      return false;
+   Gen.reset(new pkgCacheGenerator(Map.get(),Progress));
+   return Gen->Start();
+}
+bool pkgCacheGenerator::MakeStatusCache(pkgSourceList &List,OpProgress *Progress,
+			MMap **OutMap,bool)
+{
+   return pkgCacheGenerator::MakeStatusCache(List, Progress, OutMap, nullptr, true);
+}
+bool pkgCacheGenerator::MakeStatusCache(pkgSourceList &List,OpProgress *Progress,
+			MMap **OutMap,pkgCache **OutCache, bool)
+{
+   // FIXME: deprecate the ignored AllowMem parameter
+   bool const Debug = _config->FindB("Debug::pkgCacheGen", false);
+
+   std::vector<pkgIndexFile *> Files;
+   if (_system->AddStatusFiles(Files) == false)
+      return false;
+
+   // Decide if we can write to the files..
+   string const CacheFileName = _config->FindFile("Dir::Cache::pkgcache");
+   string const SrcCacheFileName = _config->FindFile("Dir::Cache::srcpkgcache");
+
+   // ensure the cache directory exists
+   if (CacheFileName.empty() == false || SrcCacheFileName.empty() == false)
+   {
+      string dir = _config->FindDir("Dir::Cache");
+      size_t const len = dir.size();
+      if (len > 5 && dir.find("/apt/", len - 6, 5) == len - 5)
+	 dir = dir.substr(0, len - 5);
+      if (CacheFileName.empty() == false)
+	 CreateDirectory(dir, flNotFile(CacheFileName));
+      if (SrcCacheFileName.empty() == false)
+	 CreateDirectory(dir, flNotFile(SrcCacheFileName));
+   }
+
+   if (Progress != NULL)
+      Progress->OverallProgress(0,1,1,_("Reading package lists"));
+
+   bool pkgcache_fine = false;
+   bool srcpkgcache_fine = false;
+   bool volatile_fine = List.GetVolatileFiles().empty();
+   FileFd CacheFile;
+   if (CheckValidity(CacheFile, CacheFileName, List, Files.begin(), Files.end(), volatile_fine ? OutMap : NULL,
+		     volatile_fine ? OutCache : NULL) == true)
+   {
+      if (Debug == true)
+	 std::clog << "pkgcache.bin is valid - no need to build any cache" << std::endl;
+      pkgcache_fine = true;
+      srcpkgcache_fine = true;
+   }
+
+   FileFd SrcCacheFile;
+   if (pkgcache_fine == false)
+   {
+      if (CheckValidity(SrcCacheFile, SrcCacheFileName, List, Files.end(), Files.end()) == true)
+      {
+	 if (Debug == true)
+	    std::clog << "srcpkgcache.bin is valid - it can be reused" << std::endl;
+	 srcpkgcache_fine = true;
+      }
+   }
+
+   if (volatile_fine == true && srcpkgcache_fine == true && pkgcache_fine == true)
+   {
+      if (Progress != NULL)
+	 Progress->OverallProgress(1,1,1,_("Reading package lists"));
+      return true;
+   }
+
+   bool Writeable = false;
+   if (srcpkgcache_fine == false || pkgcache_fine == false)
+   {
+      if (CacheFileName.empty() == false)
+	 Writeable = access(flNotFile(CacheFileName).c_str(),W_OK) == 0;
+      else if (SrcCacheFileName.empty() == false)
+	 Writeable = access(flNotFile(SrcCacheFileName).c_str(),W_OK) == 0;
+
+      if (Debug == true)
+	 std::clog << "Do we have write-access to the cache files? " << (Writeable ? "YES" : "NO") << std::endl;
+   }
+
+   // At this point we know we need to construct something, so get storage ready
+   std::unique_ptr<DynamicMMap> Map(CreateDynamicMMap(NULL, 0));
+   if (unlikely(Map->validData()) == false)
+      return false;
+   if (Debug == true)
+      std::clog << "Open memory Map (not filebased)" << std::endl;
+
+   std::unique_ptr<pkgCacheGenerator> Gen{nullptr};
+   map_filesize_t CurrentSize = 0;
+   std::vector<pkgIndexFile*> VolatileFiles = List.GetVolatileFiles();
+   map_filesize_t TotalSize = ComputeSize(NULL, VolatileFiles.begin(), VolatileFiles.end());
+   if (srcpkgcache_fine == true && pkgcache_fine == false)
+   {
+      if (Debug == true)
+	 std::clog << "srcpkgcache.bin was valid - populate MMap with it" << std::endl;
+      if (loadBackMMapFromFile(Gen, Map, Progress, SrcCacheFile) == false)
+	 return false;
+      srcpkgcache_fine = true;
+      TotalSize += ComputeSize(NULL, Files.begin(), Files.end());
+   }
+   else if (srcpkgcache_fine == false)
+   {
+      if (Debug == true)
+	 std::clog << "srcpkgcache.bin is NOT valid - rebuild" << std::endl;
+      Gen.reset(new pkgCacheGenerator(Map.get(),Progress));
+      if (Gen->Start() == false)
+	 return false;
+
+      TotalSize += ComputeSize(&List, Files.begin(),Files.end());
+      if (BuildCache(*Gen, Progress, CurrentSize, TotalSize, &List,
+	       Files.end(),Files.end()) == false)
+	 return false;
+
+      if (Writeable == true && SrcCacheFileName.empty() == false)
+	 if (writeBackMMapToFile(Gen.get(), Map.get(), SrcCacheFileName) == false)
+	    return false;
+   }
+
+   if (pkgcache_fine == false)
+   {
+      if (Debug == true)
+	 std::clog << "Building status cache in pkgcache.bin now" << std::endl;
+      if (BuildCache(*Gen, Progress, CurrentSize, TotalSize, NULL,
+	       Files.begin(), Files.end()) == false)
+	 return false;
+
+      if (Writeable == true && CacheFileName.empty() == false)
+	 if (writeBackMMapToFile(Gen.get(), Map.get(), CacheFileName) == false)
+	    return false;
+   }
+
+   if (Debug == true)
+      std::clog << "Caches done. " << (volatile_fine ? "No volatile files, so we are done here." : "Now bring in the volatile files") << std::endl;
+
+   if (volatile_fine == false)
+   {
+      if (Gen == nullptr)
+      {
+	 if (Debug == true)
+	    std::clog << "Populate new MMap with cachefile contents" << std::endl;
+	 if (loadBackMMapFromFile(Gen, Map, Progress, CacheFile) == false)
+	    return false;
+      }
+
+      Files = List.GetVolatileFiles();
+      if (BuildCache(*Gen, Progress, CurrentSize, TotalSize, NULL,
+	       Files.begin(), Files.end()) == false)
+	 return false;
+   }
+
+   if (OutMap != nullptr)
+      *OutMap = Map.release();
+
+   if (Debug == true)
+      std::clog << "Everything is ready for shipping" << std::endl;
+   return true;
+}
+									/*}}}*/
+// CacheGenerator::MakeOnlyStatusCache - Build only a status files cache/*{{{*/
+class APT_HIDDEN ScopedErrorMerge {
+public:
+   ScopedErrorMerge() { _error->PushToStack(); }
+   ~ScopedErrorMerge() { _error->MergeWithStack(); }
+};
+bool pkgCacheGenerator::MakeOnlyStatusCache(OpProgress *Progress,DynamicMMap **OutMap)
+{
+   std::vector<pkgIndexFile *> Files;
+   if (_system->AddStatusFiles(Files) == false)
+      return false;
+
+   ScopedErrorMerge sem;
+   std::unique_ptr<DynamicMMap> Map(CreateDynamicMMap(NULL, 0));
+   if (unlikely(Map->validData()) == false)
+      return false;
+   map_filesize_t CurrentSize = 0;
+   map_filesize_t TotalSize = 0;
+   TotalSize = ComputeSize(NULL, Files.begin(), Files.end());
+
+   // Build the status cache
+   if (Progress != NULL)
+      Progress->OverallProgress(0,1,1,_("Reading package lists"));
+   pkgCacheGenerator Gen(Map.get(),Progress);
+   if (Gen.Start() == false || _error->PendingError() == true)
+      return false;
+   if (BuildCache(Gen,Progress,CurrentSize,TotalSize, NULL,
+		  Files.begin(), Files.end()) == false)
+      return false;
+
+   if (_error->PendingError() == true)
+      return false;
+   *OutMap = Map.release();
+   
+   return true;
+}
+									/*}}}*/
+// IsDuplicateDescription						/*{{{*/
+static bool IsDuplicateDescription(pkgCache &Cache, pkgCache::DescIterator Desc,
+			    APT::StringView CurMd5, std::string const &CurLang)
+{
+   // Descriptions in the same link-list have all the same md5
+   if (Desc.end() == true || Cache.ViewString(Desc->md5sum) != CurMd5)
+      return false;
+   for (; Desc.end() == false; ++Desc)
+      if (Desc.LanguageCode() == CurLang)
+	 return true;
+   return false;
+}
+									/*}}}*/
+
+pkgCacheListParser::pkgCacheListParser() : Owner(NULL), OldDepLast(NULL), d(NULL) {}
+pkgCacheListParser::~pkgCacheListParser() {}
diff --git a/apt-pkg/pkgcachegen.h b/apt-pkg/pkgcachegen.h
new file mode 100644
index 0000000..f4781d7
--- /dev/null
+++ b/apt-pkg/pkgcachegen.h
@@ -0,0 +1,229 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Cache Generator - Generator for the cache structure.
+   
+   This builds the cache structure from the abstract package list parser. 
+   Each archive source has it's own list parser that is instantiated by
+   the caller to provide data for the generator. 
+   
+   Parts of the cache are created by this generator class while other
+   parts are created by the list parser. The list parser is responsible
+   for creating version, depends and provides structures, and some of
+   their contents
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PKGCACHEGEN_H
+#define PKGLIB_PKGCACHEGEN_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/mmap.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <string>
+#include <vector>
+#if __cplusplus >= 201103L
+#include <unordered_set>
+#endif
+#include <apt-pkg/string_view.h>
+
+#ifdef APT_COMPILING_APT
+#include <xxhash.h>
+#endif
+
+class FileFd;
+class pkgSourceList;
+class OpProgress;
+class pkgIndexFile;
+class pkgCacheListParser;
+
+class APT_HIDDEN pkgCacheGenerator					/*{{{*/
+{
+   APT_HIDDEN map_stringitem_t WriteStringInMap(APT::StringView String) { return WriteStringInMap(String.data(), String.size()); };
+   APT_HIDDEN map_stringitem_t WriteStringInMap(const char *String);
+   APT_HIDDEN map_stringitem_t WriteStringInMap(const char *String, const unsigned long &Len);
+   APT_HIDDEN uint32_t AllocateInMap(const unsigned long &size);
+   template<typename T> map_pointer<T> AllocateInMap() {
+      return map_pointer<T>{AllocateInMap(sizeof(T))};
+   }
+
+   // Dirty hack for public users that do not use C++11 yet
+#if __cplusplus >= 201103L && defined(APT_COMPILING_APT)
+   struct string_pointer {
+      const char *data_;
+      size_t size;
+      pkgCacheGenerator *generator;
+      map_stringitem_t item;
+
+      const char *data() const {
+	 return data_ != nullptr ? data_ : static_cast<char*>(generator->Map.Data()) + item;
+      }
+
+      bool operator ==(string_pointer const &other) const {
+	 return size == other.size && memcmp(data(), other.data(), size) == 0;
+      }
+   };
+   struct hash {
+      uint32_t operator()(string_pointer const &that) const {
+	 return XXH3_64bits(that.data(), that.size) & 0xFFFFFFFF;
+      }
+   };
+
+   std::unordered_set<string_pointer, hash> strMixed;
+   std::unordered_set<string_pointer, hash> strVersions;
+   std::unordered_set<string_pointer, hash> strSections;
+#endif
+
+   friend class pkgCacheListParser;
+   typedef pkgCacheListParser ListParser;
+
+   public:
+
+   template<typename Iter> class Dynamic {
+      public:
+      static std::vector<Iter*> toReMap;
+      explicit Dynamic(Iter &I) {
+	 toReMap.push_back(&I);
+      }
+
+      ~Dynamic() {
+	 toReMap.pop_back();
+      }
+
+#if __cplusplus >= 201103L
+      Dynamic(const Dynamic&) = delete;
+      void operator=(const Dynamic&) = delete;
+#endif
+   };
+
+   protected:
+
+   DynamicMMap &Map;
+   pkgCache Cache;
+   OpProgress *Progress;
+
+   std::string RlsFileName;
+   pkgCache::ReleaseFile *CurrentRlsFile;
+   std::string PkgFileName;
+   pkgCache::PackageFile *CurrentFile;
+
+   bool NewGroup(pkgCache::GrpIterator &Grp, APT::StringView Name);
+   bool NewPackage(pkgCache::PkgIterator &Pkg, APT::StringView Name, APT::StringView Arch);
+   map_pointer<pkgCache::Version> NewVersion(pkgCache::VerIterator &Ver, APT::StringView const &VerStr,
+			    map_pointer<pkgCache::Package> const ParentPkg, uint32_t Hash,
+			    map_pointer<pkgCache::Version> const Next);
+   map_pointer<pkgCache::Description> NewDescription(pkgCache::DescIterator &Desc,const std::string &Lang, APT::StringView md5sum,map_stringitem_t const idxmd5str);
+   bool NewFileVer(pkgCache::VerIterator &Ver,ListParser &List);
+   bool NewFileDesc(pkgCache::DescIterator &Desc,ListParser &List);
+   bool NewDepends(pkgCache::PkgIterator &Pkg, pkgCache::VerIterator &Ver,
+		   map_stringitem_t const Version, uint8_t const Op,
+		   uint8_t const Type, map_pointer<pkgCache::Dependency>* &OldDepLast);
+   bool NewProvides(pkgCache::VerIterator &Ver, pkgCache::PkgIterator &Pkg,
+		    map_stringitem_t const ProvidesVersion, uint8_t const Flags);
+
+   public:
+
+   enum StringType { MIXED, VERSIONNUMBER, SECTION };
+   map_stringitem_t StoreString(StringType const type, const char * S, unsigned int const Size);
+
+   inline map_stringitem_t StoreString(enum StringType const type, APT::StringView S) {return StoreString(type, S.data(),S.length());};
+
+   void DropProgress() {Progress = 0;};
+   bool SelectFile(const std::string &File,pkgIndexFile const &Index, std::string const &Architecture, std::string const &Component, unsigned long Flags = 0);
+   bool SelectReleaseFile(const std::string &File, const std::string &Site, unsigned long Flags = 0);
+   bool MergeList(ListParser &List,pkgCache::VerIterator *Ver = 0);
+   inline pkgCache &GetCache() {return Cache;};
+   inline pkgCache::PkgFileIterator GetCurFile()
+         {return pkgCache::PkgFileIterator(Cache,CurrentFile);};
+   inline pkgCache::RlsFileIterator GetCurRlsFile()
+         {return pkgCache::RlsFileIterator(Cache,CurrentRlsFile);};
+
+   APT_PUBLIC static bool MakeStatusCache(pkgSourceList &List,OpProgress *Progress,
+			MMap **OutMap = 0,bool AllowMem = false);
+   APT_HIDDEN static bool MakeStatusCache(pkgSourceList &List,OpProgress *Progress,
+			MMap **OutMap,pkgCache **OutCache, bool AllowMem = false);
+   APT_PUBLIC static bool MakeOnlyStatusCache(OpProgress *Progress,DynamicMMap **OutMap);
+
+   void ReMap(void const * const oldMap, void * const newMap, size_t oldSize);
+   bool Start();
+
+   pkgCacheGenerator(DynamicMMap *Map,OpProgress *Progress);
+   virtual ~pkgCacheGenerator();
+
+   private:
+   void * const d;
+   APT_HIDDEN bool MergeListGroup(ListParser &List, std::string const &GrpName);
+   APT_HIDDEN bool MergeListPackage(ListParser &List, pkgCache::PkgIterator &Pkg);
+   APT_HIDDEN bool MergeListVersion(ListParser &List, pkgCache::PkgIterator &Pkg,
+			 APT::StringView const &Version, pkgCache::VerIterator* &OutVer);
+
+   APT_HIDDEN bool AddImplicitDepends(pkgCache::GrpIterator &G, pkgCache::PkgIterator &P,
+			   pkgCache::VerIterator &V);
+   APT_HIDDEN bool AddImplicitDepends(pkgCache::VerIterator &V, pkgCache::PkgIterator &D);
+
+   APT_HIDDEN bool AddNewDescription(ListParser &List, pkgCache::VerIterator &Ver,
+	 std::string const &lang, APT::StringView CurMd5, map_stringitem_t &md5idx);
+};
+									/*}}}*/
+// This is the abstract package list parser class.			/*{{{*/
+class APT_HIDDEN pkgCacheListParser
+{
+   pkgCacheGenerator *Owner;
+   friend class pkgCacheGenerator;
+
+   // Some cache items
+   pkgCache::VerIterator OldDepVer;
+   map_pointer<pkgCache::Dependency> *OldDepLast;
+
+   void * const d;
+
+   protected:
+   inline bool NewGroup(pkgCache::GrpIterator &Grp, APT::StringView Name) { return Owner->NewGroup(Grp, Name); }
+   inline map_stringitem_t StoreString(pkgCacheGenerator::StringType const type, const char *S,unsigned int Size) {return Owner->StoreString(type, S, Size);};
+   inline map_stringitem_t StoreString(pkgCacheGenerator::StringType const type, APT::StringView S) {return Owner->StoreString(type, S);};
+   inline map_stringitem_t WriteString(APT::StringView S) {return Owner->WriteStringInMap(S.data(), S.size());};
+
+   inline map_stringitem_t WriteString(const char *S,unsigned int Size) {return Owner->WriteStringInMap(S,Size);};
+   bool NewDepends(pkgCache::VerIterator &Ver,APT::StringView Package, APT::StringView Arch,
+		   APT::StringView Version,uint8_t const Op,
+		   uint8_t const Type);
+   bool NewProvides(pkgCache::VerIterator &Ver,APT::StringView PkgName,
+		    APT::StringView PkgArch, APT::StringView Version,
+		    uint8_t const Flags);
+   bool NewProvidesAllArch(pkgCache::VerIterator &Ver, APT::StringView Package,
+			   APT::StringView Version, uint8_t const Flags);
+   public:
+   
+   // These all operate against the current section
+   virtual std::string Package() = 0;
+   virtual bool ArchitectureAll() = 0;
+   virtual APT::StringView Architecture() = 0;
+   virtual APT::StringView Version() = 0;
+   virtual bool NewVersion(pkgCache::VerIterator &Ver) = 0;
+   virtual std::vector<std::string> AvailableDescriptionLanguages() = 0;
+   virtual APT::StringView Description_md5() = 0;
+   virtual uint32_t VersionHash() = 0;
+   /** compare currently parsed version with given version
+    *
+    * \param Hash of the currently parsed version
+    * \param Ver to compare with
+    */
+   virtual bool SameVersion(uint32_t Hash, pkgCache::VerIterator const &Ver);
+   virtual bool UsePackage(pkgCache::PkgIterator &Pkg,
+			   pkgCache::VerIterator &Ver) = 0;
+   virtual map_filesize_t Offset() = 0;
+   virtual map_filesize_t Size() = 0;
+   
+   virtual bool Step() = 0;
+   
+   virtual bool CollectFileProvides(pkgCache &/*Cache*/,
+				    pkgCache::VerIterator &/*Ver*/) {return true;};
+
+   pkgCacheListParser();
+   virtual ~pkgCacheListParser();
+};
+									/*}}}*/
+
+#endif
diff --git a/apt-pkg/pkgrecords.cc b/apt-pkg/pkgrecords.cc
new file mode 100644
index 0000000..77aa8ce
--- /dev/null
+++ b/apt-pkg/pkgrecords.cc
@@ -0,0 +1,79 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Records - Allows access to complete package description records
+                     directly from the file.
+     
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/pkgrecords.h>
+
+#include <vector>
+#include <stddef.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// Records::pkgRecords - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* This will create the necessary structures to access the status files */
+pkgRecords::pkgRecords(pkgCache &aCache) : d(NULL), Cache(aCache),
+  Files(Cache.HeaderP->PackageFileCount)
+{
+   for (pkgCache::PkgFileIterator I = Cache.FileBegin();
+        I.end() == false; ++I)
+   {
+      const pkgIndexFile::Type *Type = pkgIndexFile::Type::GetType(I.IndexType());
+      if (Type == 0)
+      {
+         _error->Error(_("Index file type '%s' is not supported"),I.IndexType());
+         return;
+      }
+
+      Files[I->ID] = Type->CreatePkgParser(I);
+      if (Files[I->ID] == 0)
+         return;
+   }
+}
+									/*}}}*/
+// Records::~pkgRecords - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgRecords::~pkgRecords()
+{
+   for ( std::vector<Parser*>::iterator it = Files.begin();
+     it != Files.end();
+     ++it)
+   {
+      delete *it;
+   }
+}
+									/*}}}*/
+// Records::Lookup - Get a parser for the package version file		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgRecords::Parser &pkgRecords::Lookup(pkgCache::VerFileIterator const &Ver)
+{
+   Files[Ver.File()->ID]->Jump(Ver);
+   return *Files[Ver.File()->ID];
+}
+									/*}}}*/
+// Records::Lookup - Get a parser for the package description file	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgRecords::Parser &pkgRecords::Lookup(pkgCache::DescFileIterator const &Desc)
+{
+   Files[Desc.File()->ID]->Jump(Desc);
+   return *Files[Desc.File()->ID];
+}
+									/*}}}*/
+
+pkgRecords::Parser::Parser() : d(NULL) {}
+pkgRecords::Parser::~Parser() {}
diff --git a/apt-pkg/pkgrecords.h b/apt-pkg/pkgrecords.h
new file mode 100644
index 0000000..09c0b5f
--- /dev/null
+++ b/apt-pkg/pkgrecords.h
@@ -0,0 +1,111 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Package Records - Allows access to complete package description records
+                     directly from the file.
+   
+   The package record system abstracts the actual parsing of the 
+   package files. This is different than the generators parser in that
+   it is used to access information not generate information. No 
+   information touched by the generator should be parable from here as
+   it can always be retrieved directly from the cache.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PKGRECORDS_H
+#define PKGLIB_PKGRECORDS_H
+
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <string>
+#include <vector>
+
+class APT_PUBLIC pkgRecords							/*{{{*/
+{
+   public:
+   class Parser;
+   
+   private:
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+   
+   pkgCache &Cache;
+   std::vector<Parser *>Files;
+
+    public:
+   // Lookup function
+   Parser &Lookup(pkgCache::VerFileIterator const &Ver);
+   Parser &Lookup(pkgCache::DescFileIterator const &Desc);
+
+   // Construct destruct
+   explicit pkgRecords(pkgCache &Cache);
+   virtual ~pkgRecords();
+};
+									/*}}}*/
+class APT_PUBLIC pkgRecords::Parser						/*{{{*/
+{
+   protected:
+   
+   virtual bool Jump(pkgCache::VerFileIterator const &Ver) = 0;
+   virtual bool Jump(pkgCache::DescFileIterator const &Desc) = 0;
+   
+   public:
+   friend class pkgRecords;
+   
+   // These refer to the archive file for the Version
+   virtual std::string FileName() {return std::string();};
+   virtual std::string SourcePkg() {return std::string();};
+   virtual std::string SourceVer() {return std::string();};
+
+   /** return all known hashes in this record.
+    *
+    * For authentication proposes packages come with hashsums which
+    * this method is supposed to parse and return so that clients can
+    * choose the hash to be used.
+    */
+   virtual HashStringList Hashes() const { return HashStringList(); };
+
+   // These are some general stats about the package
+   virtual std::string Maintainer() {return std::string();};
+   /** return short description in language from record.
+    *
+    * @see #LongDesc
+    */
+   virtual std::string ShortDesc(std::string const &/*lang*/) {return std::string();};
+   /** return long description in language from record.
+    *
+    * If \b lang is empty the "best" available language will be
+    * returned as determined by the APT::Languages configuration.
+    * If a (requested) language can't be found in this record an empty
+    * string will be returned.
+    */
+   virtual std::string LongDesc(std::string const &/*lang*/) {return std::string();};
+   std::string ShortDesc() {return ShortDesc("");};
+   std::string LongDesc() {return LongDesc("");};
+
+   virtual std::string Name() {return std::string();};
+   virtual std::string Homepage() {return std::string();}
+
+   // An arbitrary custom field
+   virtual std::string RecordField(const char * /*fieldName*/) { return std::string();};
+
+   // The record in binary form
+   virtual void GetRec(const char *&Start,const char *&Stop) {Start = Stop = 0;};
+
+   Parser();
+   virtual ~Parser();
+
+   private:
+   void * const d;
+   APT_HIDDEN std::string GetHashFromHashes(char const * const type) const
+   {
+      HashStringList const hashes = Hashes();
+      HashString const * const hs = hashes.find(type);
+      return hs != NULL ? hs->HashValue() : "";
+   };
+};
+									/*}}}*/
+#endif
diff --git a/apt-pkg/pkgsystem.cc b/apt-pkg/pkgsystem.cc
new file mode 100644
index 0000000..7e48a68
--- /dev/null
+++ b/apt-pkg/pkgsystem.cc
@@ -0,0 +1,72 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   System - Abstraction for running on different systems.
+
+   Basic general structure..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/debsystem.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgsystem.h>
+
+#include <cassert>
+#include <cstring>
+#include <map>
+									/*}}}*/
+
+pkgSystem *_system = 0;
+static pkgSystem *SysList[10];
+pkgSystem **pkgSystem::GlobalList = SysList;
+unsigned long pkgSystem::GlobalListLen = 0;
+
+class APT_HIDDEN pkgSystemPrivate					/*{{{*/
+{
+public:
+   typedef decltype(pkgCache::Version::ID) idtype;
+   std::map<idtype,idtype> idmap;
+   pkgSystemPrivate() {}
+};
+									/*}}}*/
+// System::pkgSystem - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* Add it to the global list.. */
+pkgSystem::pkgSystem(char const * const label, pkgVersioningSystem * const vs) :
+   Label(label), VS(vs), d(new pkgSystemPrivate())
+{
+   assert(GlobalListLen < sizeof(SysList)/sizeof(*SysList));
+   SysList[GlobalListLen] = this;
+   ++GlobalListLen;
+}
+									/*}}}*/
+// System::GetSystem - Get the named system				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+APT_PURE pkgSystem *pkgSystem::GetSystem(const char *Label)
+{
+   for (unsigned I = 0; I != GlobalListLen; I++)
+      if (strcmp(SysList[I]->Label,Label) == 0)
+	 return SysList[I];
+   return 0;   
+}
+									/*}}}*/
+// pkgSystem::Set/GetVersionMapping - for internal/external communication/*{{{*/
+void pkgSystem::SetVersionMapping(map_id_t const in, map_id_t const out)
+{
+   if (in == out)
+      return;
+   d->idmap.emplace(in, out);
+}
+map_id_t pkgSystem::GetVersionMapping(map_id_t const in) const
+{
+   auto const o = d->idmap.find(in);
+   return (o == d->idmap.end()) ? in : o->second;
+}
+									/*}}}*/
+pkgSystem::~pkgSystem() {}
diff --git a/apt-pkg/pkgsystem.h b/apt-pkg/pkgsystem.h
new file mode 100644
index 0000000..10065d0
--- /dev/null
+++ b/apt-pkg/pkgsystem.h
@@ -0,0 +1,139 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   System - Abstraction for running on different systems.
+   
+   Instances of this class can be thought of as factories or meta-classes
+   for a variety of more specialized classes. Together this class and 
+   it's specialized offspring completely define the environment and how
+   to access resources for a specific system. There are several sub
+   areas that are all orthogonal - each system has a unique combination of
+   these sub areas:
+       - Versioning. Different systems have different ideas on versions.
+         Within a system all sub classes must follow the same versioning 
+         rules.
+       - Local tool locking to prevent multiple tools from accessing the
+         same database.
+       - Candidate Version selection policy - this is probably almost always
+         managed using a standard APT class
+       - Actual Package installation 
+         * Indication of what kind of binary formats are supported
+       - Selection of local 'status' indexes that make up the pkgCache.
+      
+   It is important to note that the handling of index files is not a 
+   function of the system. Index files are handled through a separate
+   abstraction - the only requirement is that the index files have the
+   same idea of versioning as the target system.
+   
+   Upon startup each supported system instantiates an instance of the
+   pkgSystem class (using a global constructor) which will make itself
+   available to the main APT init routine. That routine will select the
+   proper system and make it the global default.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PKGSYSTEM_H
+#define PKGLIB_PKGSYSTEM_H
+
+#include <apt-pkg/pkgcache.h>
+
+#include <vector>
+
+
+class pkgDepCache;
+class pkgPackageManager;
+class pkgVersioningSystem;
+class Configuration;
+class pkgIndexFile;
+class OpProgress;
+
+class pkgSystemPrivate;
+class APT_PUBLIC pkgSystem
+{
+   public:
+
+   // Global list of supported systems
+   static pkgSystem **GlobalList;
+   static unsigned long GlobalListLen;
+   static pkgSystem *GetSystem(const char *Label);
+   
+   const char * const Label;
+   pkgVersioningSystem * const VS;
+   
+   /* Prevent other programs from touching shared data not covered by
+      other locks (cache or state locks) */
+   virtual bool Lock(OpProgress *const Progress = nullptr) = 0;
+   virtual bool UnLock(bool NoErrors = false) = 0;
+   
+   /* Various helper classes to interface with specific bits of this
+      environment */
+   virtual pkgPackageManager *CreatePM(pkgDepCache *Cache) const = 0;
+
+   /* Load environment specific configuration and perform any other setup
+      necessary */
+   virtual bool Initialize(Configuration &/*Cnf*/) {return true;};
+   
+   /* Type is some kind of Globally Unique way of differentiating
+      archive file types.. */
+   virtual bool ArchiveSupported(const char *Type) = 0;
+
+   // Return a list of system index files..
+   virtual bool AddStatusFiles(std::vector<pkgIndexFile *> &List) = 0;
+
+   virtual bool FindIndex(pkgCache::PkgFileIterator File,
+			  pkgIndexFile *&Found) const = 0;
+
+   /* Evaluate how 'right' we are for this system based on the filesystem
+      etc.. */
+   virtual signed Score(Configuration const &/*Cnf*/) {
+      return 0;
+   };
+
+   //FIXME: these methods should be virtual
+   /** does this system has support for MultiArch?
+    *
+    * Systems supporting only single arch (not systems which are single arch)
+    * are considered legacy systems and support for it will likely degrade over
+    * time.
+    *
+    * The default implementation returns always \b true.
+    *
+    * @return \b true if the system supports MultiArch, \b false if not.
+    */
+   virtual bool MultiArchSupported() const = 0;
+   /** architectures supported by this system
+    *
+    * A MultiArch capable system might be configured to use
+    * this capability.
+    *
+    * @return a list of all architectures (native + foreign) configured
+    * for on this system (aka: which can be installed without force)
+    */
+   virtual std::vector<std::string> ArchitecturesSupported() const  = 0;
+
+   APT_HIDDEN void SetVersionMapping(map_id_t const in, map_id_t const out);
+   APT_HIDDEN map_id_t GetVersionMapping(map_id_t const in) const;
+
+   pkgSystem(char const * const Label, pkgVersioningSystem * const VS);
+   virtual ~pkgSystem();
+
+
+   /* companions to Lock()/UnLock
+    *
+    * These functions can be called prior to calling dpkg to release an inner
+    * lock without releasing the overall outer lock, so that dpkg can run
+    * correctly but no other APT instance can acquire the system lock.
+    */
+   virtual bool LockInner(OpProgress *const Progress = 0, int timeOutSec = 0) = 0;
+   virtual bool UnLockInner(bool NoErrors = false)  = 0;
+   /// checks if the system is currently locked
+   virtual bool IsLocked() = 0;
+   private:
+   pkgSystemPrivate * const d;
+};
+
+// The environment we are operating in.
+APT_PUBLIC extern pkgSystem *_system;
+
+#endif
diff --git a/apt-pkg/policy.cc b/apt-pkg/policy.cc
new file mode 100644
index 0000000..68b3f5e
--- /dev/null
+++ b/apt-pkg/policy.cc
@@ -0,0 +1,510 @@
+   // -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Package Version Policy implementation
+
+   This is just a really simple wrapper around pkgVersionMatch with
+   some added goodies to manage the list of things..
+
+   See man apt_preferences for what value means what.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/cachefilter.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/policy.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+#include <apt-pkg/version.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <iostream>
+#include <random>
+#include <sstream>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+constexpr short NEVER_PIN = std::numeric_limits<short>::min();
+
+struct pkgPolicy::Private
+{
+   std::string machineID;
+};
+
+// Policy::Init - Startup and bind to a cache				/*{{{*/
+// ---------------------------------------------------------------------
+/* Set the defaults for operation. The default mode with no loaded policy
+   file matches the V0 policy engine. */
+pkgPolicy::pkgPolicy(pkgCache *Owner) : VerPins(nullptr),
+					PFPriority(nullptr), Cache(Owner), d(new Private)
+{
+   if (Owner == 0)
+      return;
+   PFPriority = new signed short[Owner->Head().PackageFileCount];
+   VerPins = new Pin[Owner->Head().VersionCount];
+
+   auto VersionCount = Owner->Head().VersionCount;
+   for (decltype(VersionCount) I = 0; I != VersionCount; ++I)
+      VerPins[I].Type = pkgVersionMatch::None;
+
+   // The config file has a master override.
+   string DefRel = _config->Find("APT::Default-Release");
+   if (DefRel.empty() == false)
+   {
+      bool found = false;
+      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
+      {
+	 if (pkgVersionMatch::ExpressionMatches(DefRel, F.Archive()) ||
+	     pkgVersionMatch::ExpressionMatches(DefRel, F.Codename()) ||
+	     pkgVersionMatch::ExpressionMatches(DefRel, F.Version()) ||
+	     (DefRel.length() > 2 && DefRel[1] == '='))
+	    found = true;
+      }
+      // "now" is our internal archive name for the status file,
+      // which we should accept even if we have no status file at the moment
+      if (not found && pkgVersionMatch::ExpressionMatches(DefRel, "now"))
+	 found = true;
+      if (not found)
+	 _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
+      else
+	 CreatePin(pkgVersionMatch::Release,"",DefRel,990);
+   }
+   InitDefaults();
+
+   d->machineID = APT::Configuration::getMachineID();
+}
+									/*}}}*/
+// Policy::InitDefaults - Compute the default selections		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgPolicy::InitDefaults()
+{
+   // Initialize the priorities based on the status of the package file
+   for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
+   {
+      PFPriority[I->ID] = 500;
+      if (I.Flagged(pkgCache::Flag::NotSource))
+	 PFPriority[I->ID] = 100;
+      else if (I.Flagged(pkgCache::Flag::ButAutomaticUpgrades))
+	 PFPriority[I->ID] = 100;
+      else if (I.Flagged(pkgCache::Flag::NotAutomatic))
+	 PFPriority[I->ID] = 1;
+   }
+
+   // Apply the defaults..
+   std::unique_ptr<bool[]> Fixed(new bool[Cache->HeaderP->PackageFileCount]);
+   memset(Fixed.get(),0,sizeof(Fixed[0])*Cache->HeaderP->PackageFileCount);
+   StatusOverride = false;
+   for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
+   {
+      pkgVersionMatch Match(I->Data,I->Type);
+      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
+      {
+	 if ((Fixed[F->ID] == false || I->Priority == NEVER_PIN) && PFPriority[F->ID] != NEVER_PIN && Match.FileMatch(F) == true)
+	 {
+	    PFPriority[F->ID] = I->Priority;
+
+	    if (PFPriority[F->ID] >= 1000)
+	       StatusOverride = true;
+
+	    Fixed[F->ID] = true;
+	 }
+      }
+   }
+
+   if (_config->FindB("Debug::pkgPolicy",false) == true)
+      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
+	 std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
+
+   return true;
+}
+									/*}}}*/
+// Policy::GetCandidateVer - Get the candidate install version		/*{{{*/
+// ---------------------------------------------------------------------
+/* Evaluate the package pins and the default list to determine what the
+   best package is. */
+pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
+{
+   pkgCache::VerIterator cand;
+   pkgCache::VerIterator cur = Pkg.CurrentVer();
+   int candPriority = -1;
+   pkgVersioningSystem *vs = Cache->VS;
+
+   for (pkgCache::VerIterator ver = Pkg.VersionList(); ver.end() == false; ++ver) {
+      int priority = GetPriority(ver, true);
+
+      if (priority == 0 || priority <= candPriority)
+	 continue;
+
+      // TODO: Maybe optimize to not compare versions
+      if (!cur.end() && priority < 1000
+	  && (vs->CmpVersion(ver.VerStr(), cur.VerStr()) < 0))
+	 continue;
+
+      candPriority = priority;
+      cand = ver;
+   }
+
+   return cand;
+}
+									/*}}}*/
+// Policy::CreatePin - Create an entry in the pin table..		/*{{{*/
+// ---------------------------------------------------------------------
+/* For performance we have 3 tables, the default table, the main cache
+   table (hashed to the cache). A blank package name indicates the pin
+   belongs to the default table. Order of insertion matters here, the
+   earlier defaults override later ones. */
+void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
+			  string Data,signed short Priority)
+{
+   if (Name.empty() == true)
+   {
+      Pin *P = &*Defaults.insert(Defaults.end(),Pin());
+      P->Type = Type;
+      P->Priority = Priority;
+      P->Data = Data;
+      return;
+   }
+
+   bool IsSourcePin = APT::String::Startswith(Name, "src:");
+   if (IsSourcePin) {
+      Name = Name.substr(sizeof("src:") - 1);
+   }
+
+   size_t found = Name.rfind(':');
+   string Arch;
+   if (found != string::npos) {
+      Arch = Name.substr(found+1);
+      Name.erase(found);
+   }
+
+   // Allow pinning by wildcards - beware of package names looking like wildcards!
+   // TODO: Maybe we should always prefer specific pins over non-specific ones.
+   if ((Name[0] == '/' && Name[Name.length() - 1] == '/') || Name.find_first_of("*[?") != string::npos)
+   {
+      pkgVersionMatch match(Data, Type);
+      for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
+	 if (Name != G.Name() && match.ExpressionMatches(Name, G.Name()))
+	 {
+	    auto NameToPinFor = IsSourcePin ? string("src:").append(G.Name()) : string(G.Name());
+	    if (Arch.empty() == false)
+	       CreatePin(Type, NameToPinFor.append(":").append(Arch), Data, Priority);
+	    else
+	       CreatePin(Type, NameToPinFor, Data, Priority);
+	 }
+      return;
+   }
+
+   // find the package (group) this pin applies to
+   pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
+   bool matched = false;
+   if (Grp.end() == false)
+   {
+      std::string MatchingArch;
+      if (Arch.empty() == true)
+	 MatchingArch = Cache->NativeArch();
+      else
+	 MatchingArch = Arch;
+      APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
+
+      if (IsSourcePin) {
+	 for (pkgCache::VerIterator Ver = Grp.VersionsInSource(); not Ver.end(); Ver = Ver.NextInSource())
+	 {
+	    if (pams(Ver.ParentPkg().Arch()) == false)
+	       continue;
+
+	    PkgPin P(Ver.ParentPkg().FullName());
+	    P.Type = Type;
+	    P.Priority = Priority;
+	    P.Data = Data;
+	    // Find matching version(s) and copy the pin into it
+	    pkgVersionMatch Match(P.Data,P.Type);
+	    if (Match.VersionMatches(Ver)) {
+	       Pin *VP = VerPins + Ver->ID;
+	       if (VP->Type == pkgVersionMatch::None) {
+		  *VP = P;
+		   matched = true;
+	       }
+	    }
+	 }
+      } else {
+	 for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
+	 {
+	    if (pams(Pkg.Arch()) == false)
+	       continue;
+
+	    PkgPin P(Pkg.FullName());
+	    P.Type = Type;
+	    P.Priority = Priority;
+	    P.Data = Data;
+
+	    // Find matching version(s) and copy the pin into it
+	    pkgVersionMatch Match(P.Data,P.Type);
+	    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() != true; ++Ver)
+	    {
+	       if (Match.VersionMatches(Ver)) {
+		  Pin *VP = VerPins + Ver->ID;
+		  if (VP->Type == pkgVersionMatch::None) {
+		     *VP = P;
+		      matched = true;
+		  }
+	       }
+	    }
+	 }
+      }
+   }
+
+   if (matched == false)
+   {
+      PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
+      if (Arch.empty() == false)
+	 P->Pkg.append(":").append(Arch);
+      P->Type = Type;
+      P->Priority = Priority;
+      P->Data = Data;
+      return;
+   }
+}
+									/*}}}*/
+// Policy::GetPriority - Get the priority of the package pin		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+// Returns true if this update is excluded by phasing.
+static inline bool ExcludePhased(std::string machineID, pkgCache::VerIterator const &Ver)
+{
+   if (Ver.PhasedUpdatePercentage() == 100)
+      return false;
+
+   // FIXME: We have migrated to a legacy implementation until LP: #1929082 is fixed
+   if (not _config->FindB("APT::Get::Phase-Policy", false))
+      return false;
+
+   // The order and fallbacks for the always/never checks come from update-manager and exist
+   // to preserve compatibility.
+   if (_config->FindB("APT::Get::Always-Include-Phased-Updates",
+		      _config->FindB("Update-Manager::Always-Include-Phased-Updates", false)))
+      return false;
+
+   if (_config->FindB("APT::Get::Never-Include-Phased-Updates",
+		      _config->FindB("Update-Manager::Never-Include-Phased-Updates", false)))
+      return true;
+
+   if (machineID.empty()			 // no machine-id
+       || getenv("SOURCE_DATE_EPOCH") != nullptr // reproducible build - always include
+       || APT::Configuration::isChroot())
+      return false;
+
+   std::string seedStr = std::string(Ver.SourcePkgName()) + "-" + Ver.SourceVerStr() + "-" + machineID;
+   std::seed_seq seed(seedStr.begin(), seedStr.end());
+   std::minstd_rand rand(seed);
+   std::uniform_int_distribution<unsigned int> dist(0, 100);
+
+   return dist(rand) > Ver.PhasedUpdatePercentage();
+}
+APT_PURE signed short pkgPolicy::GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles)
+{
+   auto ceiling = std::numeric_limits<signed int>::max();
+   if (ExcludePhased(d->machineID, Ver))
+      ceiling = 1;
+   if (VerPins[Ver->ID].Type != pkgVersionMatch::None)
+   {
+      // If all sources are never pins, the never pin wins.
+      if (VerPins[Ver->ID].Priority == NEVER_PIN)
+	 return NEVER_PIN;
+      for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
+	 if (GetPriority(file.File()) != NEVER_PIN)
+	    return std::min((int)VerPins[Ver->ID].Priority, ceiling);
+   }
+   if (!ConsiderFiles)
+      return std::min(0, ceiling);
+
+   // priorities are short ints, but we want to pick a value outside the valid range here
+   auto priority = std::numeric_limits<signed int>::min();
+   for (pkgCache::VerFileIterator file = Ver.FileList(); file.end() == false; file++)
+   {
+      /* If this is the status file, and the current version is not the
+         version in the status file (ie it is not installed, or somesuch)
+         then it is not a candidate for installation, ever. This weeds
+         out bogus entries that may be due to config-file states, or
+         other. */
+      if (file.File().Flagged(pkgCache::Flag::NotSource) && Ver.ParentPkg().CurrentVer() != Ver)
+	 priority = std::max<decltype(priority)>(priority, -1);
+      else
+	 priority = std::max<decltype(priority)>(priority, GetPriority(file.File()));
+   }
+
+   return std::min(priority == std::numeric_limits<decltype(priority)>::min() ? 0 : priority, ceiling);
+}
+APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
+{
+   return PFPriority[File->ID];
+}
+									/*}}}*/
+// SetPriority - Directly set priority					/*{{{*/
+// ---------------------------------------------------------------------
+void pkgPolicy::SetPriority(pkgCache::VerIterator const &Ver, signed short Priority)
+{
+   Pin pin;
+   pin.Data = "pkgPolicy::SetPriority";
+   pin.Priority = Priority;
+   VerPins[Ver->ID] = pin;
+}
+void pkgPolicy::SetPriority(pkgCache::PkgFileIterator const &File, signed short Priority)
+{
+   PFPriority[File->ID] = Priority;
+}
+
+									/*}}}*/
+// ReadPinDir - Load the pin files from this dir into a Policy		/*{{{*/
+// ---------------------------------------------------------------------
+/* This will load each pin file in the given dir into a Policy. If the
+   given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
+   Note also that this method will issue a warning if the dir does not
+   exists but it will return true in this case! */
+bool ReadPinDir(pkgPolicy &Plcy,string Dir)
+{
+   if (Dir.empty() == true)
+      Dir = _config->FindDir("Dir::Etc::PreferencesParts", "/dev/null");
+
+   if (DirectoryExists(Dir) == false)
+   {
+      if (APT::String::Endswith(Dir, "/dev/null") == false)
+	 _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
+      return true;
+   }
+
+   _error->PushToStack();
+   vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
+   bool const PendingErrors = _error->PendingError();
+   _error->MergeWithStack();
+   if (PendingErrors)
+      return false;
+
+   // Read the files
+   bool good = true;
+   for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
+      good = ReadPinFile(Plcy, *I) && good;
+   return good;
+}
+									/*}}}*/
+// ReadPinFile - Load the pin file into a Policy			/*{{{*/
+// ---------------------------------------------------------------------
+/* I'd like to see the preferences file store more than just pin information
+   but right now that is the only stuff I have to store. Later there will
+   have to be some kind of combined super parser to get the data into all
+   the right classes.. */
+bool ReadPinFile(pkgPolicy &Plcy,string File)
+{
+   if (File.empty() == true)
+      File = _config->FindFile("Dir::Etc::Preferences");
+
+   if (RealFileExists(File) == false)
+      return true;
+
+   FileFd Fd;
+   if (OpenConfigurationFileFd(File, Fd) == false)
+      return false;
+
+   pkgTagFile TF(&Fd, pkgTagFile::SUPPORT_COMMENTS);
+   if (Fd.IsOpen() == false || Fd.Failed())
+      return false;
+
+   pkgTagSection Tags;
+   while (TF.Step(Tags) == true)
+   {
+      // can happen when there are only comments in a record
+      if (Tags.Count() == 0)
+         continue;
+
+      auto Name = Tags.Find(pkgTagSection::Key::Package);
+      if (Name.empty())
+	 return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
+      if (Name == "*")
+	 Name = APT::StringView{};
+
+      const char *Start;
+      const char *End;
+      if (Tags.Find("Pin",Start,End) == false)
+	 continue;
+	 
+      const char *Word = Start;
+      for (; Word != End && isspace(*Word) == 0; Word++);
+
+      // Parse the type..
+      pkgVersionMatch::MatchType Type;
+      if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
+	 Type = pkgVersionMatch::Version;
+      else if (stringcasecmp(Start,Word,"release") == 0)
+	 Type = pkgVersionMatch::Release;
+      else if (stringcasecmp(Start,Word,"origin") == 0)
+	 Type = pkgVersionMatch::Origin;
+      else
+      {
+	 _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
+	 continue;
+      }
+      for (; Word != End && isspace(*Word) != 0; Word++);
+
+      _error->PushToStack();
+      std::string sPriority = Tags.FindS("Pin-Priority");
+      int priority = sPriority == "never" ? NEVER_PIN : Tags.FindI("Pin-Priority", 0);
+      bool const newError = _error->PendingError();
+      _error->MergeWithStack();
+
+      if (sPriority == "never" && not Name.empty())
+	 return _error->Error(_("%s: The special 'Pin-Priority: %s' can only be used for 'Package: *' records"), File.c_str(), "never");
+
+      // Silently clamp the never pin to never pin + 1
+      if (priority == NEVER_PIN && sPriority != "never")
+	 priority = NEVER_PIN + 1;
+      if (priority < std::numeric_limits<short>::min() ||
+          priority > std::numeric_limits<short>::max() ||
+	  newError) {
+	 return _error->Error(_("%s: Value %s is outside the range of valid pin priorities (%d to %d)"),
+			      File.c_str(), Tags.FindS("Pin-Priority").c_str(),
+			      std::numeric_limits<short>::min(),
+			      std::numeric_limits<short>::max());
+      }
+      if (priority == 0)
+      {
+         return _error->Error(_("No priority (or zero) specified for pin"));
+      }
+
+      std::istringstream s(Name.to_string());
+      string pkg;
+      while(!s.eof())
+      {
+	 s >> pkg;
+         Plcy.CreatePin(Type, pkg, string(Word,End),priority);
+      };
+   }
+
+   Plcy.InitDefaults();
+   return true;
+}
+									/*}}}*/
+
+pkgPolicy::~pkgPolicy()
+{
+   delete[] PFPriority;
+   delete[] VerPins;
+   delete d;
+}
diff --git a/apt-pkg/policy.h b/apt-pkg/policy.h
new file mode 100644
index 0000000..589cebc
--- /dev/null
+++ b/apt-pkg/policy.h
@@ -0,0 +1,93 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Package Version Policy implementation
+
+   This implements the more advanced 'Version 4' APT policy engine. The
+   standard 'Version 0' engine is included inside the DepCache which is
+   it's historical location.
+   
+   The V4 engine allows the user to completely control all aspects of
+   version selection. There are three primary means to choose a version
+    * Selection by version match
+    * Selection by Release file match
+    * Selection by origin server
+   
+   Each package may be 'pinned' with a single criteria, which will ultimately
+   result in the selection of a single version, or no version, for each
+   package.
+   
+   Furthermore, the default selection can be influenced by specifying
+   the ordering of package files. The order is derived by reading the
+   package file preferences and assigning a priority to each package 
+   file.
+   
+   A special flag may be set to indicate if no version should be returned
+   if no matching versions are found, otherwise the default matching
+   rules are used to locate a hit.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_POLICY_H
+#define PKGLIB_POLICY_H
+
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <string>
+#include <vector>
+
+
+class APT_PUBLIC pkgPolicy : public pkgDepCache::Policy
+{
+   protected:
+
+   struct Pin
+   {
+      pkgVersionMatch::MatchType Type;
+      std::string Data;
+      signed short Priority;
+      Pin() : Type(pkgVersionMatch::None), Priority(0) {};
+   };
+
+   struct PkgPin : Pin
+   {
+      std::string Pkg;
+      explicit PkgPin(std::string const &Pkg) : Pin(), Pkg(Pkg) {};
+   };
+
+   Pin *VerPins;
+   signed short *PFPriority;
+   std::vector<Pin> Defaults;
+   std::vector<PkgPin> Unmatched;
+   pkgCache *Cache;
+   bool StatusOverride;
+   
+   public:
+
+   // Things for manipulating pins
+   void CreatePin(pkgVersionMatch::MatchType Type,std::string Pkg,
+		  std::string Data,signed short Priority);
+
+   // Things for the cache interface.
+   virtual pkgCache::VerIterator GetCandidateVer(pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
+   virtual signed short GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles = true) APT_OVERRIDE;
+   virtual signed short GetPriority(pkgCache::PkgFileIterator const &File) APT_OVERRIDE;
+
+   void SetPriority(pkgCache::VerIterator const &Ver, signed short Priority);
+   void SetPriority(pkgCache::PkgFileIterator const &File, signed short Priority);
+   bool InitDefaults();
+   
+   explicit pkgPolicy(pkgCache *Owner);
+   virtual ~pkgPolicy();
+   private:
+   struct Private;
+   Private *const d;
+};
+
+APT_PUBLIC bool ReadPinFile(pkgPolicy &Plcy, std::string File = "");
+APT_PUBLIC bool ReadPinDir(pkgPolicy &Plcy, std::string Dir = "");
+
+#endif
diff --git a/apt-pkg/prettyprinters.cc b/apt-pkg/prettyprinters.cc
new file mode 100644
index 0000000..87e78bb
--- /dev/null
+++ b/apt-pkg/prettyprinters.cc
@@ -0,0 +1,123 @@
+// Description								/*{{{*/
+/* ######################################################################
+
+   Provide pretty printers for pkgCache structs like PkgIterator
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/prettyprinters.h>
+
+#include <ostream>
+#include <string>
+
+									/*}}}*/
+
+std::ostream& operator<<(std::ostream& os, const APT::PrettyPkg& pp)	/*{{{*/
+{
+   if (pp.Pkg.end() == true)
+      return os << "invalid package";
+
+   auto state = (*pp.DepCache)[pp.Pkg];
+   std::string const current = (pp.Pkg.CurVersion() == 0 ? "none" : pp.Pkg.CurVersion());
+   std::string candidate = state.CandVersion;
+   if (candidate.empty())
+      candidate = "none";
+   std::string install = "none";
+   if (state.InstallVer != nullptr)
+      install = state.InstVerIter(*pp.DepCache).VerStr();
+
+   os << pp.Pkg.FullName(false) << " < " << current;
+   if (current != install && install != "none")
+      os << " -> " << install;
+   if (install != candidate && current != candidate)
+      os << " | " << candidate;
+   os << " @";
+   switch (pp.Pkg->SelectedState)
+   {
+      case pkgCache::State::Unknown: os << 'u'; break;
+      case pkgCache::State::Install: os << 'i'; break;
+      case pkgCache::State::Hold: os << 'h'; break;
+      case pkgCache::State::DeInstall: os << 'r'; break;
+      case pkgCache::State::Purge: os << 'p'; break;
+      default: os << 'X';
+   }
+   switch (pp.Pkg->InstState)
+   {
+      case pkgCache::State::Ok: break;
+      case pkgCache::State::ReInstReq: os << 'R'; break;
+      case pkgCache::State::HoldInst: os << 'H'; break;
+      case pkgCache::State::HoldReInstReq: os << "HR"; break;
+      default: os << 'X';
+   }
+   switch (pp.Pkg->CurrentState)
+   {
+      case pkgCache::State::NotInstalled: os << 'n'; break;
+      case pkgCache::State::ConfigFiles: os << 'c'; break;
+      case pkgCache::State::HalfInstalled: os << 'H'; break;
+      case pkgCache::State::UnPacked: os << 'U'; break;
+      case pkgCache::State::HalfConfigured: os << 'F'; break;
+      case pkgCache::State::TriggersAwaited: os << 'W'; break;
+      case pkgCache::State::TriggersPending: os << 'T'; break;
+      case pkgCache::State::Installed: os << 'i'; break;
+      default: os << 'X';
+   }
+   os << ' ';
+   if (state.Protect())
+      os << "p";
+   if (state.ReInstall())
+      os << "r";
+   if (state.Upgradable())
+      os << "u";
+   if (state.Marked)
+      os << "m";
+   if (state.Garbage)
+      os << "g";
+   if (state.NewInstall())
+      os << "N";
+   else if (state.Upgrade())
+      os << "U";
+   else if (state.Downgrade())
+      os << "D";
+   else if (state.Install())
+      os << "I";
+   else if (state.Purge())
+      os << "P";
+   else if (state.Delete())
+      os << "R";
+   else if (state.Held())
+      os << "H";
+   else if (state.Keep())
+      os << "K";
+   if (state.NowBroken())
+      os << " Nb";
+   else if (state.NowPolicyBroken())
+      os << " NPb";
+   if (state.InstBroken())
+      os << " Ib";
+   else if (state.InstPolicyBroken())
+      os << " IPb";
+   os << " >";
+   return os;
+}
+									/*}}}*/
+std::ostream& operator<<(std::ostream& os, const APT::PrettyDep& pd)	/*{{{*/
+{
+   if (unlikely(pd.Dep.end() == true))
+      return os << "invalid dependency";
+
+   pkgCache::PkgIterator P = pd.Dep.ParentPkg();
+   pkgCache::PkgIterator T = pd.Dep.TargetPkg();
+
+   os << (P.end() ? "invalid pkg" : P.FullName(false)) << " " << pd.Dep.DepType()
+	<< " on " << APT::PrettyPkg(pd.DepCache, T);
+
+   if (pd.Dep->Version != 0)
+      os << " (" << pd.Dep.CompType() << " " << pd.Dep.TargetVer() << ")";
+
+   return os;
+}
+									/*}}}*/
diff --git a/apt-pkg/prettyprinters.h b/apt-pkg/prettyprinters.h
new file mode 100644
index 0000000..80b7729
--- /dev/null
+++ b/apt-pkg/prettyprinters.h
@@ -0,0 +1,37 @@
+#ifndef APT_PRETTYPRINTERS_H
+#define APT_PRETTYPRINTERS_H
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+class pkgDepCache;
+
+namespace APT {
+
+/** helper to format PkgIterator for easier printing in debug messages.
+ *
+ * The actual text generated is subject to change without prior notice
+ * and should NOT be used as part of a general user interface.
+ */
+struct PrettyPkg
+{
+   pkgDepCache * const DepCache;
+   pkgCache::PkgIterator const Pkg;
+   PrettyPkg(pkgDepCache * const depcache, pkgCache::PkgIterator const &pkg) APT_NONNULL(2) : DepCache(depcache), Pkg(pkg) {}
+};
+/** helper to format DepIterator for easier printing in debug messages.
+ *
+ * The actual text generated is subject to change without prior notice
+ * and should NOT be used as part of a general user interface.
+ */
+struct PrettyDep
+{
+   pkgDepCache * const DepCache;
+   pkgCache::DepIterator const Dep;
+   PrettyDep(pkgDepCache * const depcache, pkgCache::DepIterator const &dep) APT_NONNULL(2) : DepCache(depcache), Dep(dep) {}
+};
+
+}
+APT_PUBLIC std::ostream& operator<<(std::ostream& os, const APT::PrettyPkg& pp);
+APT_PUBLIC std::ostream& operator<<(std::ostream& os, const APT::PrettyDep& pd);
+
+#endif
diff --git a/apt-pkg/sourcelist.cc b/apt-pkg/sourcelist.cc
new file mode 100644
index 0000000..0ac59fc
--- /dev/null
+++ b/apt-pkg/sourcelist.cc
@@ -0,0 +1,626 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   List of Sources
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cmndline.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debindexfile.h>
+#include <apt-pkg/debsrcrecords.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <cstring>
+#include <fstream>
+#include <map>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <stddef.h>
+#include <time.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// Global list of Items supported
+static pkgSourceList::Type *ItmList[10];
+pkgSourceList::Type **pkgSourceList::Type::GlobalList = ItmList;
+unsigned long pkgSourceList::Type::GlobalListLen = 0;
+
+static std::vector<std::string> FindMultiValue(pkgTagSection &Tags, char const *const Field) /*{{{*/
+{
+   auto values = Tags.FindS(Field);
+   // we ignore duplicate spaces by removing empty values
+   std::replace_if(values.begin(), values.end(), isspace_ascii, ' ');
+   auto vect = VectorizeString(values, ' ');
+   vect.erase(std::remove_if(vect.begin(), vect.end(), [](std::string const &s) { return s.empty(); }), vect.end());
+   return vect;
+}
+									/*}}}*/
+
+// Type::Type - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* Link this to the global list of items*/
+pkgSourceList::Type::Type(char const * const pName, char const * const pLabel) : Name(pName), Label(pLabel)
+{
+   ItmList[GlobalListLen] = this;
+   ++GlobalListLen;
+}
+pkgSourceList::Type::~Type() {}
+									/*}}}*/
+// Type::GetType - Get a specific meta for a given type			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgSourceList::Type *pkgSourceList::Type::GetType(const char *Type)
+{
+   for (unsigned I = 0; I != GlobalListLen; ++I)
+      if (strcmp(GlobalList[I]->Name,Type) == 0)
+	 return GlobalList[I];
+   return 0;
+}
+									/*}}}*/
+// Type::FixupURI - Normalize the URI and check it..			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::Type::FixupURI(string &URI) const
+{
+   if (URI.empty() == true)
+      return false;
+
+   if (URI.find(':') == string::npos)
+      return false;
+
+   URI = ::URI{SubstVar(URI, "$(ARCH)", _config->Find("APT::Architecture"))};
+
+   // Make sure that the URI is / postfixed
+   if (URI.back() != '/')
+      URI.push_back('/');
+
+   return true;
+}
+									/*}}}*/
+bool pkgSourceList::Type::ParseStanza(vector<metaIndex *> &List,	/*{{{*/
+                                      pkgTagSection &Tags,
+                                      unsigned int const i,
+                                      FileFd &Fd)
+{
+   map<string, string> Options;
+
+   string Enabled = Tags.FindS("Enabled");
+   if (Enabled.empty() == false && StringToBool(Enabled) == false)
+      return true;
+
+   std::map<char const * const, std::pair<char const * const, bool> > mapping;
+#define APT_PLUSMINUS(X, Y) \
+   mapping.insert(std::make_pair(X, std::make_pair(Y, true))); \
+   mapping.insert(std::make_pair(X "-Add", std::make_pair(Y "+", true))); \
+   mapping.insert(std::make_pair(X "-Remove", std::make_pair(Y "-", true)))
+   APT_PLUSMINUS("Architectures", "arch");
+   APT_PLUSMINUS("Languages", "lang");
+   APT_PLUSMINUS("Targets", "target");
+#undef APT_PLUSMINUS
+   mapping.insert(std::make_pair("Trusted", std::make_pair("trusted", false)));
+   mapping.insert(std::make_pair("Check-Valid-Until", std::make_pair("check-valid-until", false)));
+   mapping.insert(std::make_pair("Valid-Until-Min", std::make_pair("valid-until-min", false)));
+   mapping.insert(std::make_pair("Valid-Until-Max", std::make_pair("valid-until-max", false)));
+   mapping.insert(std::make_pair("Check-Date", std::make_pair("check-date", false)));
+   mapping.insert(std::make_pair("Date-Max-Future", std::make_pair("date-max-future", false)));
+   mapping.insert(std::make_pair("Signed-By", std::make_pair("signed-by", false)));
+   mapping.insert(std::make_pair("PDiffs", std::make_pair("pdiffs", false)));
+   mapping.insert(std::make_pair("By-Hash", std::make_pair("by-hash", false)));
+
+   for (std::map<char const * const, std::pair<char const * const, bool> >::const_iterator m = mapping.begin(); m != mapping.end(); ++m)
+      if (Tags.Exists(m->first))
+      {
+	 if (m->second.second)
+	 {
+	    auto const values = FindMultiValue(Tags, m->first);
+	    Options[m->second.first] = APT::String::Join(values, ",");
+	 }
+	 else
+	    Options[m->second.first] = Tags.FindS(m->first);
+      }
+
+   {
+      std::string entry;
+      strprintf(entry, "%s:%i", Fd.Name().c_str(), i);
+      Options["sourceslist-entry"] = entry;
+   }
+
+   // now create one item per suite/section
+   auto const list_uris = FindMultiValue(Tags, "URIs");
+   auto const list_comp = FindMultiValue(Tags, "Components");
+   auto list_suite = FindMultiValue(Tags, "Suites");
+   {
+      auto const nativeArch = _config->Find("APT::Architecture");
+      std::transform(list_suite.begin(), list_suite.end(), list_suite.begin(),
+		     [&](std::string const &suite) { return SubstVar(suite, "$(ARCH)", nativeArch); });
+   }
+
+   if (list_uris.empty())
+      // TRANSLATOR: %u is a line number, the first %s is a filename of a file with the extension "second %s" and the third %s is a unique identifier for bugreports
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), i, "sources", Fd.Name().c_str(), "URI");
+
+   if (list_suite.empty())
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), i, "sources", Fd.Name().c_str(), "Suite");
+
+   for (auto URI : list_uris)
+   {
+      if (FixupURI(URI) == false)
+	 return _error->Error(_("Malformed entry %u in %s file %s (%s)"), i, "sources", Fd.Name().c_str(), "URI parse");
+
+      for (auto const &S : list_suite)
+      {
+	 if (likely(S.empty() == false) && S[S.size() - 1] == '/')
+	 {
+	    if (list_comp.empty() == false)
+	       return _error->Error(_("Malformed entry %u in %s file %s (%s)"), i, "sources", Fd.Name().c_str(), "absolute Suite Component");
+	    if (CreateItem(List, URI, S, "", Options) == false)
+	       return false;
+	 }
+	 else
+	 {
+	    if (list_comp.empty())
+	       return _error->Error(_("Malformed entry %u in %s file %s (%s)"), i, "sources", Fd.Name().c_str(), "Component");
+
+	    for (auto const &C : list_comp)
+	       if (CreateItem(List, URI, S, C, Options) == false)
+		  return false;
+	 }
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// Type::ParseLine - Parse a single line				/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a generic one that is the 'usual' format for sources.list
+   Weird types may override this. */
+bool pkgSourceList::Type::ParseLine(vector<metaIndex *> &List,
+				    const char *Buffer,
+				    unsigned int const CurLine,
+				    string const &File) const
+{
+   for (;Buffer != 0 && isspace(*Buffer); ++Buffer); // Skip whitespaces
+
+   // Parse option field if it exists
+   // e.g.: [ option1=value1 option2=value2 ]
+   map<string, string> Options;
+   {
+      std::string entry;
+      strprintf(entry, "%s:%i", File.c_str(), CurLine);
+      Options["sourceslist-entry"] = entry;
+   }
+   if (Buffer != 0 && Buffer[0] == '[')
+   {
+      ++Buffer; // ignore the [
+      for (;Buffer != 0 && isspace(*Buffer); ++Buffer); // Skip whitespaces
+      while (*Buffer != ']')
+      {
+	 // get one option, e.g. option1=value1
+	 string option;
+	 if (ParseQuoteWord(Buffer,option) == false)
+	    return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "[option] unparsable");
+
+	 if (option.length() < 3)
+	    return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "[option] too short");
+
+	 // accept options even if the last has no space before the ]-end marker
+	 if (option.at(option.length()-1) == ']')
+	 {
+	    for (; *Buffer != ']'; --Buffer);
+	    option.resize(option.length()-1);
+	 }
+
+	 size_t const needle = option.find('=');
+	 if (needle == string::npos)
+	    return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "[option] not assignment");
+
+	 string const key = string(option, 0, needle);
+	 string const value = string(option, needle + 1, option.length());
+
+	 if (key.empty() == true)
+	    return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "[option] no key");
+
+	 if (value.empty() == true)
+	    return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "[option] no value");
+
+	 Options[key] = value;
+      }
+      ++Buffer; // ignore the ]
+      for (;Buffer != 0 && isspace(*Buffer); ++Buffer); // Skip whitespaces
+   }
+
+   string URI;
+   string Dist;
+   string Section;
+
+   if (ParseQuoteWord(Buffer,URI) == false)
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "URI");
+   if (ParseQuoteWord(Buffer,Dist) == false)
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "Suite");
+
+   if (FixupURI(URI) == false)
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "URI parse");
+
+   // Check for an absolute dists specification.
+   if (Dist.empty() == false && Dist[Dist.size() - 1] == '/')
+   {
+      if (ParseQuoteWord(Buffer,Section) == true)
+	 return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "absolute Suite Component");
+      Dist = SubstVar(Dist,"$(ARCH)",_config->Find("APT::Architecture"));
+      return CreateItem(List, URI, Dist, Section, Options);
+   }
+
+   // Grab the rest of the dists
+   if (ParseQuoteWord(Buffer,Section) == false)
+      return _error->Error(_("Malformed entry %u in %s file %s (%s)"), CurLine, "list", File.c_str(), "Component");
+
+   do
+   {
+      if (CreateItem(List, URI, Dist, Section, Options) == false)
+	 return false;
+   }
+   while (ParseQuoteWord(Buffer,Section) == true);
+
+   return true;
+}
+									/*}}}*/
+// SourceList::pkgSourceList - Constructors				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgSourceList::pkgSourceList() : d(NULL)
+{
+}
+									/*}}}*/
+// SourceList::~pkgSourceList - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgSourceList::~pkgSourceList()
+{
+   for (const_iterator I = SrcList.begin(); I != SrcList.end(); ++I)
+      delete *I;
+   SrcList.clear();
+   for (auto  F = VolatileFiles.begin(); F != VolatileFiles.end(); ++F)
+      delete (*F);
+   VolatileFiles.clear();
+}
+									/*}}}*/
+// SourceList::ReadMainList - Read the main source list from etc	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::ReadMainList()
+{
+   Reset();
+   // CNC:2003-11-28 - Entries in sources.list have priority over
+   //                  entries in sources.list.d.
+   string Main = _config->FindFile("Dir::Etc::sourcelist", "/dev/null");
+   string Parts = _config->FindDir("Dir::Etc::sourceparts", "/dev/null");
+
+   _error->PushToStack();
+   if (RealFileExists(Main) == true)
+      ReadAppend(Main);
+   else if (DirectoryExists(Parts) == false && APT::String::Endswith(Parts, "/dev/null") == false)
+      // Only warn if there are no sources.list.d.
+      _error->WarningE("DirectoryExists", _("Unable to read %s"), Parts.c_str());
+
+   if (DirectoryExists(Parts) == true)
+      ReadSourceDir(Parts);
+   else if (Main.empty() == false && RealFileExists(Main) == false &&
+	 APT::String::Endswith(Parts, "/dev/null") == false)
+      // Only warn if there is no sources.list file.
+      _error->WarningE("RealFileExists", _("Unable to read %s"), Main.c_str());
+
+   for (auto && file: _config->FindVector("APT::Sources::With"))
+      AddVolatileFile(file, nullptr);
+
+   auto good = _error->PendingError() == false;
+   _error->MergeWithStack();
+   return good;
+}
+									/*}}}*/
+// SourceList::Reset - Clear the sourcelist contents			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void pkgSourceList::Reset()
+{
+   for (const_iterator I = SrcList.begin(); I != SrcList.end(); ++I)
+      delete *I;
+   SrcList.clear();
+}
+									/*}}}*/
+// SourceList::Read - Parse the sourcelist file				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::Read(string const &File)
+{
+   Reset();
+   return ReadAppend(File);
+}
+									/*}}}*/
+// SourceList::ReadAppend - Parse a sourcelist file			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::ReadAppend(string const &File)
+{
+   if (flExtension(File) == "sources")
+      return ParseFileDeb822(File);
+   else
+      return ParseFileOldStyle(File);
+}
+									/*}}}*/
+// SourceList::ReadFileOldStyle - Read Traditional style sources.list 	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::ParseFileOldStyle(std::string const &File)
+{
+   FileFd Fd;
+   if (OpenConfigurationFileFd(File, Fd) == false)
+      return false;
+
+   std::string Buffer;
+   for (unsigned int CurLine = 1; Fd.ReadLine(Buffer); ++CurLine)
+   {
+      // remove comments
+      size_t curpos = 0;
+      while ((curpos = Buffer.find('#', curpos)) != std::string::npos)
+      {
+	 size_t const openbrackets = std::count(Buffer.begin(), Buffer.begin() + curpos, '[');
+	 size_t const closedbrackets = std::count(Buffer.begin(), Buffer.begin() + curpos, ']');
+	 if (openbrackets > closedbrackets)
+	 {
+	    // a # in an option, unlikely, but oh well, it was supported so stick to it
+	    ++curpos;
+	    continue;
+	 }
+	 Buffer.erase(curpos);
+	 break;
+      }
+      // remove spaces before/after
+      curpos = Buffer.find_first_not_of(" \t\r");
+      if (curpos != 0)
+	 Buffer.erase(0, curpos);
+      curpos = Buffer.find_last_not_of(" \t\r");
+      if (curpos != std::string::npos)
+	 Buffer.erase(curpos + 1);
+
+      if (Buffer.empty())
+	 continue;
+
+      // Grok it
+      std::string const LineType = Buffer.substr(0, Buffer.find_first_of(" \t\v"));
+      if (LineType.empty() || LineType == Buffer)
+	 return _error->Error(_("Malformed line %u in source list %s (type)"),CurLine,File.c_str());
+
+      Type *Parse = Type::GetType(LineType.c_str());
+      if (Parse == 0)
+	 return _error->Error(_("Type '%s' is not known on line %u in source list %s"),LineType.c_str(),CurLine,File.c_str());
+
+      if (Parse->ParseLine(SrcList, Buffer.c_str() + LineType.length(), CurLine, File) == false)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+// SourceList::ParseFileDeb822 - Parse deb822 style sources.list 	/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns: the number of stanzas parsed*/
+bool pkgSourceList::ParseFileDeb822(string const &File)
+{
+   // see if we can read the file
+   FileFd Fd;
+   if (OpenConfigurationFileFd(File, Fd) == false)
+      return false;
+   pkgTagFile Sources(&Fd, pkgTagFile::SUPPORT_COMMENTS);
+   if (Fd.IsOpen() == false || Fd.Failed())
+      return _error->Error(_("Malformed stanza %u in source list %s (type)"),0,File.c_str());
+
+   // read step by step
+   pkgTagSection Tags;
+   unsigned int i = 0;
+   while (Sources.Step(Tags) == true)
+   {
+      ++i;
+      if(Tags.Exists("Types") == false)
+	 return _error->Error(_("Malformed stanza %u in source list %s (type)"),i,File.c_str());
+
+      for (auto const &type : FindMultiValue(Tags, "Types"))
+      {
+	 Type *Parse = Type::GetType(type.c_str());
+	 if (Parse == 0)
+	 {
+	    _error->Error(_("Type '%s' is not known on stanza %u in source list %s"), type.c_str(), i, Fd.Name().c_str());
+	    return false;
+	 }
+
+	 if (!Parse->ParseStanza(SrcList, Tags, i, Fd))
+	    return false;
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// SourceList::FindIndex - Get the index associated with a file		/*{{{*/
+static bool FindInIndexFileContainer(std::vector<pkgIndexFile *> const &Cont, pkgCache::PkgFileIterator const &File, pkgIndexFile *&Found)
+{
+   auto const J = std::find_if(Cont.begin(), Cont.end(), [&File](pkgIndexFile const * const J) {
+	 return J->FindInCache(*File.Cache()) == File;
+   });
+   if (J != Cont.end())
+   {
+      Found = (*J);
+      return true;
+   }
+   return false;
+}
+bool pkgSourceList::FindIndex(pkgCache::PkgFileIterator File,
+			      pkgIndexFile *&Found) const
+{
+   for (const_iterator I = SrcList.begin(); I != SrcList.end(); ++I)
+      if (FindInIndexFileContainer(*(*I)->GetIndexFiles(), File, Found))
+	 return true;
+
+   return FindInIndexFileContainer(VolatileFiles, File, Found);
+}
+									/*}}}*/
+// SourceList::GetIndexes - Load the index files into the downloader	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::GetIndexes(pkgAcquire *Owner, bool GetAll) const
+{
+   for (const_iterator I = SrcList.begin(); I != SrcList.end(); ++I)
+      if ((*I)->GetIndexes(Owner,GetAll) == false)
+	 return false;
+   return true;
+}
+									/*}}}*/
+// CNC:2003-03-03 - By Anton V. Denisov <avd@altlinux.org>.
+// SourceList::ReadSourceDir - Read a directory with sources files
+// Based on ReadConfigDir()						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgSourceList::ReadSourceDir(string const &Dir)
+{
+   std::vector<std::string> const ext = {"list", "sources"};
+   // Read the files
+   bool good = true;
+   for (auto const &I : GetListOfFilesInDir(Dir, ext, true))
+      good = ReadAppend(I) && good;
+   return good;
+}
+									/*}}}*/
+// GetLastModified()						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+time_t pkgSourceList::GetLastModifiedTime()
+{
+   vector<string> List;
+
+   string Main = _config->FindFile("Dir::Etc::sourcelist");
+   string Parts = _config->FindDir("Dir::Etc::sourceparts");
+
+   // go over the parts
+   if (DirectoryExists(Parts) == true)
+      List = GetListOfFilesInDir(Parts, "list", true);
+
+   // calculate the time
+   std::vector<time_t> modtimes;
+   modtimes.reserve(1 + List.size());
+   modtimes.push_back(GetModificationTime(Main));
+   std::transform(List.begin(), List.end(), std::back_inserter(modtimes), GetModificationTime);
+   auto const maxmtime = std::max_element(modtimes.begin(), modtimes.end());
+   return *maxmtime;
+}
+									/*}}}*/
+std::vector<pkgIndexFile*> pkgSourceList::GetVolatileFiles() const	/*{{{*/
+{
+   return VolatileFiles;
+}
+									/*}}}*/
+void pkgSourceList::AddVolatileFile(pkgIndexFile * const File)		/*{{{*/
+{
+   if (File != nullptr)
+      VolatileFiles.push_back(File);
+}
+									/*}}}*/
+static bool fileNameMatches(std::string const &filename, std::string const &idxtype)/*{{{*/
+{
+   for (auto && type: APT::Configuration::getCompressionTypes())
+   {
+      if (type == "uncompressed")
+      {
+	 if (filename == idxtype || APT::String::Endswith(filename, '_' + idxtype))
+	    return true;
+      }
+      else if (filename == idxtype + '.' + type ||
+	    APT::String::Endswith(filename, '_' + idxtype + '.' + type))
+	 return true;
+   }
+   return false;
+}
+									/*}}}*/
+bool pkgSourceList::AddVolatileFile(std::string const &File, std::vector<std::string> * const VolatileCmdL)/*{{{*/
+{
+   // Note: FileExists matches directories and links, too!
+   if (File.empty() || FileExists(File) == false)
+      return false;
+
+   std::string const ext = flExtension(File);
+   // udeb is not included as installing it is usually a mistake rather than intended
+   if (ext == "deb" || ext == "ddeb")
+      AddVolatileFile(new debDebPkgFileIndex(File));
+   else if (ext == "dsc")
+      AddVolatileFile(new debDscFileIndex(File));
+   else if (FileExists(flCombine(File, "debian/control")))
+      AddVolatileFile(new debDscFileIndex(flCombine(File, "debian/control")));
+   else if (ext == "changes")
+   {
+      debDscRecordParser changes(File, nullptr);
+      std::vector<pkgSrcRecords::File> fileslst;
+      if (changes.Files(fileslst) == false || fileslst.empty())
+	 return false;
+      auto const basedir = flNotFile(File);
+      for (auto && file: fileslst)
+      {
+	 auto const name = flCombine(basedir, file.Path);
+	 AddVolatileFile(name, VolatileCmdL);
+	 if (file.Hashes.VerifyFile(name) == false)
+	    return _error->Error("The file %s does not match with the hashes in the %s file!", name.c_str(), File.c_str());
+      }
+      return true;
+   }
+   else
+   {
+      auto const filename = flNotDir(File);
+      auto const Target = IndexTarget(File, filename, File, "file:" + File, false, true, {
+	 { "FILENAME", File },
+	 { "REPO_URI", "file:" + flAbsPath(flNotFile(File)) + '/' },
+	 { "COMPONENT", "volatile-packages-file" },
+      });
+      if (fileNameMatches(filename, "Packages"))
+	 AddVolatileFile(new debPackagesIndex(Target, true));
+      else if (fileNameMatches(filename, "Sources"))
+	 AddVolatileFile(new debSourcesIndex(Target, true));
+      else
+	 return false;
+   }
+
+   if (VolatileCmdL != nullptr)
+      VolatileCmdL->push_back(File);
+   return true;
+}
+bool pkgSourceList::AddVolatileFile(std::string const &File)
+{
+   return AddVolatileFile(File, nullptr);
+}
+									/*}}}*/
+void pkgSourceList::AddVolatileFiles(CommandLine &CmdL, std::vector<std::string> * const VolatileCmdL)/*{{{*/
+{
+   std::remove_if(CmdL.FileList + 1, CmdL.FileList + 1 + CmdL.FileSize(), [&](char const * const I) {
+      if (I != nullptr && (I[0] == '/' || (I[0] == '.' && (I[1] == '\0' || (I[1] == '.' && (I[2] == '\0' || I[2] == '/')) || I[1] == '/'))))
+      {
+	 if (AddVolatileFile(I, VolatileCmdL))
+	    ;
+	 else
+	    _error->Error(_("Unsupported file %s given on commandline"), I);
+	 return true;
+      }
+      return false;
+   });
+}
+									/*}}}*/
diff --git a/apt-pkg/sourcelist.h b/apt-pkg/sourcelist.h
new file mode 100644
index 0000000..4541803
--- /dev/null
+++ b/apt-pkg/sourcelist.h
@@ -0,0 +1,135 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   SourceList - Manage a list of sources
+   
+   The Source List class provides access to a list of sources. It 
+   can read them from a file and generate a list of all the distinct
+   sources.
+   
+   All sources have a type associated with them that defines the layout
+   of the archive. The exact format of the file is documented in
+   files.sgml.
+
+   The types are mapped through a list of type definitions which handle
+   the actual construction of the back end type. After loading a source 
+   list all you have is a list of package index files that have the ability
+   to be Acquired.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_SOURCELIST_H
+#define PKGLIB_SOURCELIST_H
+
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <time.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+
+class FileFd;
+class pkgTagSection;
+class pkgAcquire;
+class pkgIndexFile;
+class metaIndex;
+class CommandLine;
+
+class APT_PUBLIC pkgSourceList
+{
+   void * const d;
+   std::vector<pkgIndexFile*> VolatileFiles;
+   public:
+
+   // List of supported source list types
+   class Type
+   {
+      public:
+
+      // Global list of Items supported
+      static Type **GlobalList;
+      static unsigned long GlobalListLen;
+      static Type *GetType(const char *Type) APT_PURE;
+
+      char const * const Name;
+      char const * const Label;
+
+      bool FixupURI(std::string &URI) const;
+      virtual bool ParseStanza(std::vector<metaIndex *> &List,
+                               pkgTagSection &Tags,
+                               unsigned int const stanza_n,
+                               FileFd &Fd);
+      virtual bool ParseLine(std::vector<metaIndex *> &List,
+			     const char *Buffer,
+			     unsigned int const CurLine,std::string const &File) const;
+      virtual bool CreateItem(std::vector<metaIndex *> &List,std::string const &URI,
+			      std::string const &Dist,std::string const &Section,
+			      std::map<std::string, std::string> const &Options) const = 0;
+      Type(char const * const Name, char const * const Label);
+      virtual ~Type();
+   };
+
+   typedef std::vector<metaIndex *>::const_iterator const_iterator;
+
+   protected:
+
+   std::vector<metaIndex *> SrcList;
+
+   private:
+   APT_HIDDEN bool ParseFileDeb822(std::string const &File);
+   APT_HIDDEN bool ParseFileOldStyle(std::string const &File);
+
+   public:
+
+   bool ReadMainList();
+   bool Read(std::string const &File);
+
+   // CNC:2003-03-03
+   void Reset();
+   bool ReadAppend(std::string const &File);
+   bool ReadSourceDir(std::string const &Dir);
+   
+   // List accessors
+   inline const_iterator begin() const {return SrcList.begin();};
+   inline const_iterator end() const {return SrcList.end();};
+   inline unsigned int size() const {return SrcList.size();};
+   inline bool empty() const {return SrcList.empty();};
+
+   bool FindIndex(pkgCache::PkgFileIterator File,
+		  pkgIndexFile *&Found) const;
+   bool GetIndexes(pkgAcquire *Owner, bool GetAll=false) const;
+   
+   // query last-modified time
+   time_t GetLastModifiedTime();
+
+   /** \brief add file for parsing, but not to the cache
+    *
+    *  pkgIndexFiles originating from pkgSourcesList are included in
+    *  srcpkgcache, the status files added via #AddStatusFiles are
+    *  included in pkgcache, but these files here are not included in
+    *  any cache to have the possibility of having a file included just
+    *  for a single run like a local .deb/.dsc file.
+    *
+    *  The volatile files do not count as "normal" sourceslist entries,
+    *  can't be iterated over with #begin and #end and can't be
+    *  downloaded, but they can be found via #FindIndex.
+    *
+    *  @param File is an index file; pointer-ownership is transferred
+    */
+   void AddVolatileFile(pkgIndexFile * const File);
+   bool AddVolatileFile(std::string const &File);
+   bool AddVolatileFile(std::string const &File, std::vector<std::string> * const VolatileCmdL);
+   void AddVolatileFiles(CommandLine &CmdL, std::vector<std::string> * const VolatileCmdL);
+
+   /** @return list of files registered with #AddVolatileFile */
+   std::vector<pkgIndexFile*> GetVolatileFiles() const;
+
+   pkgSourceList();
+   virtual ~pkgSourceList();
+};
+
+#endif
diff --git a/apt-pkg/srcrecords.cc b/apt-pkg/srcrecords.cc
new file mode 100644
index 0000000..03bda75
--- /dev/null
+++ b/apt-pkg/srcrecords.cc
@@ -0,0 +1,152 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Source Package Records - Allows access to source package records
+   
+   Parses and allows access to the list of source records and searching by
+   source name on that list.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/debsrcrecords.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/indexfile.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/metaindex.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/srcrecords.h>
+
+#include <string>
+#include <vector>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// SrcRecords::pkgSrcRecords - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* Open all the source index files */
+pkgSrcRecords::pkgSrcRecords(pkgSourceList &List) : d(NULL), Files(0)
+{
+   for (pkgSourceList::const_iterator I = List.begin(); I != List.end(); ++I)
+   {
+      std::vector<pkgIndexFile *> *Indexes = (*I)->GetIndexFiles();
+      for (std::vector<pkgIndexFile *>::const_iterator J = Indexes->begin();
+	   J != Indexes->end(); ++J)
+      {
+	 _error->PushToStack();
+	 Parser* P = (*J)->CreateSrcParser();
+	 bool const newError = _error->PendingError();
+	 _error->MergeWithStack();
+	 if (newError)
+	    return;
+	 if (P != 0)
+	    Files.push_back(P);
+      }
+   }
+   
+   // Doesn't work without any source index files
+   if (Files.empty() == true)
+   {
+      _error->Error(_("You must put some 'deb-src' URIs"
+		    " in your sources.list"));
+      return;
+   }   
+
+   Restart();
+}
+									/*}}}*/
+// SrcRecords::~pkgSrcRecords - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgSrcRecords::~pkgSrcRecords()
+{
+   // Blow away all the parser objects
+   for(std::vector<Parser*>::iterator I = Files.begin(); I != Files.end(); ++I)
+      delete *I;
+}
+									/*}}}*/
+// SrcRecords::Restart - Restart the search				/*{{{*/
+// ---------------------------------------------------------------------
+/* Return all of the parsers to their starting position */
+bool pkgSrcRecords::Restart()
+{
+   Current = Files.begin();
+   for (std::vector<Parser*>::iterator I = Files.begin();
+        I != Files.end(); ++I)
+      if ((*I)->Offset() != 0)
+	 (*I)->Restart();
+
+   return true;
+}
+									/*}}}*/
+// SrcRecords::Step - Step to the next Source Record			/*{{{*/
+// ---------------------------------------------------------------------
+/* Step to the next source package record */
+const pkgSrcRecords::Parser* pkgSrcRecords::Step()
+{
+   if (Current == Files.end())
+      return 0;
+
+   // Step to the next record, possibly switching files
+   while ((*Current)->Step() == false)
+   {
+      ++Current;
+      if (Current == Files.end())
+         return 0;
+   }
+
+   return *Current;
+}
+									/*}}}*/
+// SrcRecords::Find - Find the first source package with the given name	/*{{{*/
+// ---------------------------------------------------------------------
+/* This searches on both source package names and output binary names and
+   returns the first found. A 'cursor' like system is used to allow this
+   function to be called multiple times to get successive entries */
+pkgSrcRecords::Parser *pkgSrcRecords::Find(const char *Package,bool const &SrcOnly)
+{
+   while (true)
+   {
+      if(Step() == 0)
+         return 0;
+
+      // Source name hit
+      if ((*Current)->Package() == Package)
+	 return *Current;
+      
+      if (SrcOnly == true)
+	 continue;
+      
+      // Check for a binary hit
+      const char **I = (*Current)->Binaries();
+      for (; I != 0 && *I != 0; ++I)
+	 if (strcmp(Package,*I) == 0)
+	    return *Current;
+   }
+}
+									/*}}}*/
+// Parser::BuildDepType - Convert a build dep to a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+const char *pkgSrcRecords::Parser::BuildDepType(unsigned char const &Type)
+{
+   const char *fields[] = {"Build-Depends",
+			   "Build-Depends-Indep",
+			   "Build-Conflicts",
+			   "Build-Conflicts-Indep",
+			   "Build-Depends-Arch",
+			   "Build-Conflicts-Arch"};
+   if (unlikely(Type >= sizeof(fields)/sizeof(fields[0])))
+      return "";
+   return fields[Type];
+}
+									/*}}}*/
+
+
+pkgSrcRecords::Parser::Parser(const pkgIndexFile *Index) : d(NULL), iIndex(Index) {}
+pkgSrcRecords::Parser::~Parser() {}
diff --git a/apt-pkg/srcrecords.h b/apt-pkg/srcrecords.h
new file mode 100644
index 0000000..b9014a5
--- /dev/null
+++ b/apt-pkg/srcrecords.h
@@ -0,0 +1,108 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Source Package Records - Allows access to source package records
+   
+   Parses and allows access to the list of source records and searching by
+   source name on that list.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_SRCRECORDS_H
+#define PKGLIB_SRCRECORDS_H
+
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+
+#include <string>
+#include <vector>
+
+
+class pkgSourceList;
+class pkgIndexFile;
+class APT_PUBLIC pkgSrcRecords
+{
+   public:
+
+   // Describes a single file
+   struct File
+   {
+      std::string Path;
+      std::string Type;
+      unsigned long long FileSize;
+      HashStringList Hashes;
+   };
+
+   // Abstract parser for each source record
+   class Parser
+   {
+      void * const d;
+      protected:
+      
+      const pkgIndexFile *iIndex;
+      
+      public:
+
+      enum BuildDep {BuildDepend=0x0,BuildDependIndep=0x1,
+	             BuildConflict=0x2,BuildConflictIndep=0x3,
+	             BuildDependArch=0x4,BuildConflictArch=0x5};
+
+      struct BuildDepRec 
+      {
+	 std::string Package;
+	 std::string Version;
+	 unsigned int Op;
+	 unsigned char Type;
+      };
+	
+      inline const pkgIndexFile &Index() const {return *iIndex;};
+      
+      virtual bool Restart() = 0;
+      virtual bool Step() = 0;
+      virtual bool Jump(unsigned long const &Off) = 0;
+      virtual unsigned long Offset() = 0;
+      virtual std::string AsStr() = 0;
+      
+      virtual std::string Package() const = 0;
+      virtual std::string Version() const = 0;
+      virtual std::string Maintainer() const = 0;
+      virtual std::string Section() const = 0;
+      virtual const char **Binaries() = 0;   // Ownership does not transfer
+
+      //FIXME: Add a parameter to specify which architecture to use for [wildcard] matching
+      virtual bool BuildDepends(std::vector<BuildDepRec> &BuildDeps, bool const &ArchOnly, bool const &StripMultiArch = true) = 0;
+      static const char *BuildDepType(unsigned char const &Type) APT_PURE;
+
+      virtual bool Files(std::vector<pkgSrcRecords::File> &F) = 0;
+
+      explicit Parser(const pkgIndexFile *Index);
+      virtual ~Parser();
+   };
+   
+   private:
+   /** \brief dpointer placeholder (for later in case we need it) */
+   void * const d;
+   
+   // The list of files and the current parser pointer
+   std::vector<Parser*> Files;
+   std::vector<Parser *>::iterator Current;
+   
+   public:
+
+   // Reset the search
+   bool Restart();
+
+   // Step to the next SourcePackage and return pointer to the 
+   // next SourceRecord. The pointer is owned by libapt.
+   const Parser* Step();
+
+   // Locate a package by name and return pointer to the Parser.
+   // The pointer is owned by libapt.
+   Parser* Find(const char *Package,bool const &SrcOnly = false);
+
+   explicit pkgSrcRecords(pkgSourceList &List);
+   virtual ~pkgSrcRecords();
+};
+
+#endif
diff --git a/apt-pkg/statechanges.cc b/apt-pkg/statechanges.cc
new file mode 100644
index 0000000..bbcde71
--- /dev/null
+++ b/apt-pkg/statechanges.cc
@@ -0,0 +1,231 @@
+#include <config.h>
+
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/debsystem.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/prettyprinters.h>
+#include <apt-pkg/statechanges.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <memory>
+
+namespace APT
+{
+
+class StateChanges::Private
+{
+public:
+   APT::VersionVector hold;
+   APT::VersionVector unhold;
+   APT::VersionVector install;
+   APT::VersionVector deinstall;
+   APT::VersionVector purge;
+   APT::VersionVector error;
+};
+
+#define APT_GETTERSETTER(Name, Container) \
+void StateChanges::Name(pkgCache::VerIterator const &Ver) \
+{ \
+   if (Ver.end() == false) \
+      Container.push_back(Ver); \
+}\
+APT::VersionVector& StateChanges::Name() \
+{ \
+   return Container; \
+}
+APT_GETTERSETTER(Hold, d->hold)
+APT_GETTERSETTER(Unhold, d->unhold)
+APT_GETTERSETTER(Install, d->install)
+APT_GETTERSETTER(Remove, d->deinstall)
+APT_GETTERSETTER(Purge, d->purge)
+#undef APT_GETTERSETTER
+APT::VersionVector& StateChanges::Error()
+{
+   return d->error;
+}
+
+void StateChanges::clear()
+{
+   d->hold.clear();
+   d->unhold.clear();
+   d->install.clear();
+   d->deinstall.clear();
+   d->purge.clear();
+   d->error.clear();
+}
+
+bool StateChanges::empty() const
+{
+   return d->hold.empty() &&
+      d->unhold.empty() &&
+      d->install.empty() &&
+      d->deinstall.empty() &&
+      d->purge.empty() &&
+      d->error.empty();
+}
+
+bool StateChanges::Save(bool const DiscardOutput)
+{
+   bool const Debug = _config->FindB("Debug::pkgDpkgPm", false);
+   d->error.clear();
+   if (d->hold.empty() && d->unhold.empty() && d->install.empty() && d->deinstall.empty() && d->purge.empty())
+      return true;
+
+   std::vector<std::string> Args = debSystem::GetDpkgBaseCommand();
+   // ensure dpkg knows about the package so that it keeps the status we set
+   if (d->hold.empty() == false || d->install.empty() == false)
+   {
+      APT::VersionVector makeDpkgAvailable;
+      auto const notInstalled = [](pkgCache::VerIterator const &V) { return V.ParentPkg()->CurrentVer == 0; };
+      std::copy_if(d->hold.begin(), d->hold.end(), std::back_inserter(makeDpkgAvailable), notInstalled);
+      std::copy_if(d->install.begin(), d->install.end(), std::back_inserter(makeDpkgAvailable), notInstalled);
+
+      if (makeDpkgAvailable.empty() == false)
+      {
+	 auto const BaseArgs = Args.size();
+	 Args.push_back("--merge-avail");
+	 // FIXME: supported only since 1.17.7 in dpkg
+	 Args.push_back("-");
+	 int dummyAvail = -1;
+	 if (Debug)
+	 {
+	    for (auto const &V: makeDpkgAvailable)
+	    {
+	       std::clog << "echo 'Dummy record for " << V.ParentPkg().FullName(false) << "' | ";
+	       std::copy(Args.begin(), Args.end(), std::ostream_iterator<std::string>(std::clog, " "));
+	       std::clog << std::endl;
+	    }
+	 }
+	 else
+	 {
+	    pid_t const dpkgMergeAvail = debSystem::ExecDpkg(Args, &dummyAvail, nullptr, true);
+
+	    FILE* dpkg = fdopen(dummyAvail, "w");
+	    for (auto const &V: makeDpkgAvailable)
+	       fprintf(dpkg, "Package: %s\nVersion: 0~\nArchitecture: %s\nMaintainer: Dummy Example <dummy@example.org>\n"
+		     "Description: dummy package record\n A record is needed to put a package on hold, so here it is.\n\n", V.ParentPkg().Name(), V.Arch());
+	    fclose(dpkg);
+
+	    ExecWait(dpkgMergeAvail, "dpkg --merge-avail", true);
+	 }
+	 Args.erase(Args.begin() + BaseArgs, Args.end());
+      }
+   }
+   bool const dpkgMultiArch = _system->MultiArchSupported();
+
+   Args.push_back("--set-selections");
+   if (Debug)
+   {
+      std::string state;
+      auto const dpkgName = [&](pkgCache::VerIterator const &V) {
+	 pkgCache::PkgIterator P = V.ParentPkg();
+	 if (strcmp(V.Arch(), "none") == 0)
+	    ioprintf(std::clog, "echo '%s %s' | ", P.Name(), state.c_str());
+	 else if (dpkgMultiArch == false)
+	    ioprintf(std::clog, "echo '%s %s' | ", P.FullName(true).c_str(), state.c_str());
+	 else
+	    ioprintf(std::clog, "echo '%s:%s %s' | ", P.Name(), V.Arch(), state.c_str());
+	 std::copy(Args.begin(), Args.end(), std::ostream_iterator<std::string>(std::clog, " "));
+	 std::clog << std::endl;
+      };
+      for (auto const &V: d->unhold)
+      {
+	 if (V.ParentPkg()->CurrentVer != 0)
+	    state = "install";
+	 else
+	    state = "deinstall";
+	 dpkgName(V);
+      }
+      if (d->purge.empty() == false)
+      {
+	 state = "purge";
+	 std::for_each(d->purge.begin(), d->purge.end(), dpkgName);
+      }
+      if (d->deinstall.empty() == false)
+      {
+	 state = "deinstall";
+	 std::for_each(d->deinstall.begin(), d->deinstall.end(), dpkgName);
+      }
+      if (d->hold.empty() == false)
+      {
+	 state = "hold";
+	 std::for_each(d->hold.begin(), d->hold.end(), dpkgName);
+      }
+      if (d->install.empty() == false)
+      {
+	 state = "install";
+	 std::for_each(d->install.begin(), d->install.end(), dpkgName);
+      }
+   }
+   else
+   {
+      int selections = -1;
+      pid_t const dpkgSelections = debSystem::ExecDpkg(Args, &selections, nullptr, DiscardOutput);
+
+      FILE* dpkg = fdopen(selections, "w");
+      std::string state;
+      auto const dpkgName = [&](pkgCache::VerIterator const &V) {
+	 pkgCache::PkgIterator P = V.ParentPkg();
+	 if (strcmp(V.Arch(), "none") == 0)
+	    fprintf(dpkg, "%s %s\n", P.Name(), state.c_str());
+	 else if (dpkgMultiArch == false)
+	    fprintf(dpkg, "%s %s\n", P.FullName(true).c_str(), state.c_str());
+	 else
+	    fprintf(dpkg, "%s:%s %s\n", P.Name(), V.Arch(), state.c_str());
+      };
+      for (auto const &V: d->unhold)
+      {
+	 if (V.ParentPkg()->CurrentVer != 0)
+	    state = "install";
+	 else
+	    state = "deinstall";
+	 dpkgName(V);
+      }
+      if (d->purge.empty() == false)
+      {
+	 state = "purge";
+	 std::for_each(d->purge.begin(), d->purge.end(), dpkgName);
+      }
+      if (d->deinstall.empty() == false)
+      {
+	 state = "deinstall";
+	 std::for_each(d->deinstall.begin(), d->deinstall.end(), dpkgName);
+      }
+      if (d->hold.empty() == false)
+      {
+	 state = "hold";
+	 std::for_each(d->hold.begin(), d->hold.end(), dpkgName);
+      }
+      if (d->install.empty() == false)
+      {
+	 state = "install";
+	 std::for_each(d->install.begin(), d->install.end(), dpkgName);
+      }
+      fclose(dpkg);
+
+      if (ExecWait(dpkgSelections, "dpkg --set-selections") == false)
+      {
+	 std::move(d->purge.begin(), d->purge.end(), std::back_inserter(d->error));
+	 d->purge.clear();
+	 std::move(d->deinstall.begin(), d->deinstall.end(), std::back_inserter(d->error));
+	 d->deinstall.clear();
+	 std::move(d->hold.begin(), d->hold.end(), std::back_inserter(d->error));
+	 d->hold.clear();
+	 std::move(d->unhold.begin(), d->unhold.end(), std::back_inserter(d->error));
+	 d->unhold.clear();
+	 std::move(d->install.begin(), d->install.end(), std::back_inserter(d->error));
+	 d->install.clear();
+      }
+   }
+   return d->error.empty();
+}
+
+StateChanges::StateChanges() : d(new StateChanges::Private()) {}
+StateChanges::StateChanges(StateChanges&&) = default;
+StateChanges& StateChanges::operator=(StateChanges&&) = default;
+StateChanges::~StateChanges() = default;
+
+}
diff --git a/apt-pkg/statechanges.h b/apt-pkg/statechanges.h
new file mode 100644
index 0000000..2f63d51
--- /dev/null
+++ b/apt-pkg/statechanges.h
@@ -0,0 +1,58 @@
+#include <apt-pkg/cacheset.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgcache.h>
+
+#include <memory>
+
+namespace APT
+{
+
+/** Simple wrapper class to abstract away the differences in storing different
+ *  states in different places potentially in different versions.
+ */
+class APT_PUBLIC StateChanges
+{
+public:
+   // getter/setter for the different states
+#define APT_GETTERSETTER(Name) \
+   APT::VersionVector& Name(); \
+   void Name(pkgCache::VerIterator const &Ver)
+   APT_GETTERSETTER(Hold);
+   APT_GETTERSETTER(Unhold);
+   APT_GETTERSETTER(Install);
+   APT_GETTERSETTER(Remove);
+   APT_GETTERSETTER(Purge);
+   APT::VersionVector& Error();
+#undef APT_GETTERSETTER
+
+   // operate on all containers at once
+   void clear();
+   bool empty() const;
+
+   /** commit the staged changes to the database(s).
+    *
+    * Makes the needed calls to store the requested states.
+    * After this call the state containers will hold only versions
+    * for which the storing operation succeeded. Versions where the
+    * storing operation failed are collected in #Error(). Note that
+    * error is an upper bound as states are changed in batches so it
+    * isn't always clear which version triggered the failure exactly.
+    *
+    * @param DiscardOutput controls if stdout/stderr should be used
+    *   by subprocesses for (detailed) error reporting if needed.
+    * @return \b false if storing failed, true otherwise.
+    *   Note that some states might be applied even if the whole operation failed.
+    */
+   bool Save(bool const DiscardOutput = false);
+
+   StateChanges();
+   StateChanges(StateChanges&&);
+   StateChanges& operator=(StateChanges&&);
+   ~StateChanges();
+
+private:
+   class APT_HIDDEN Private;
+   std::unique_ptr<Private> d;
+};
+
+}
diff --git a/apt-pkg/tagfile-keys.list b/apt-pkg/tagfile-keys.list
new file mode 100644
index 0000000..4b57e46
--- /dev/null
+++ b/apt-pkg/tagfile-keys.list
@@ -0,0 +1,82 @@
+# This file is input for triehash(1) (after stripping comments)
+#
+# The fields listed here are accessible via pkgTagSection::Key::FIELD
+# Do *NOT* edit, remove or insert new fields in the sorted section here
+# as the file forms part of the ABI of the libapt library and is used
+# by our apt tools. External clients are forbidden though, so if really needed
+# we can use libapt Breaks: apt, but always prefer appending only.
+#
+# For Fields used in Packages, Sources and status files, see also tagfile-order.c
+Architecture
+Auto-Built-Package
+Binary
+Breaks
+Build-Conflicts
+Build-Conflicts-Arch
+Build-Conflicts-Indep
+Build-Depends
+Build-Depends-Arch
+Build-Depends-Indep
+Build-Essential
+Built-For-Profiles
+Built-Using
+Checksums-Md5
+Checksums-Sha1
+Checksums-Sha256
+Checksums-Sha512
+Conffiles
+Config-Version
+Conflicts
+Depends
+Description
+Description-md5
+Directory
+Enhances
+Essential
+Filename
+Files
+Format
+Homepage
+Important
+Installed-Size
+Maintainer
+MD5sum
+Multi-Arch
+Origin
+Original-Maintainer
+Package
+Package-List
+Package-Type
+Phased-Update-Percentage
+Pre-Depends
+Priority
+Protected
+Provides
+Recommends
+Replaces
+Section
+SHA1
+SHA256
+SHA512
+Size
+Source
+Standards-Version
+Static-Built-Using
+Status
+Suggests
+Tag
+Task
+Testsuite
+Testsuite-Triggers
+Uploaders
+Vcs-Arch
+Vcs-Browser
+Vcs-Bzr
+Vcs-Cvs
+Vcs-Darcs
+Vcs-Git
+Vcs-Hg
+Vcs-Mtn
+Vcs-Svn
+Version
+### APPEND BELOW, sort in with next ABI break ###
diff --git a/apt-pkg/tagfile-order.c b/apt-pkg/tagfile-order.c
new file mode 100644
index 0000000..7cf188c
--- /dev/null
+++ b/apt-pkg/tagfile-order.c
@@ -0,0 +1,118 @@
+/* In this file is the order defined in which e.g. apt-ftparchive will write stanzas in.
+   Other commands might or might not use this. 'apt-cache show' e.g. does NOT!
+
+   The order we chose here is inspired by both dpkg and dak.
+   The testcase test/integration/test-apt-tagfile-fields-order intends to ensure that
+   this file isn't lacking (too far) behind dpkg over time. */
+
+static const char *iTFRewritePackageOrder[] = {
+   "Package",
+   "Package-Type",
+   "Architecture",
+   "Subarchitecture", // NO_KEY: Used only by d-i
+   "Version",
+// "Revision",         // Obsolete (warning in dpkg)
+// "Package-Revision", // Obsolete (warning in dpkg)
+// "Package_Revision", // Obsolete (warning in dpkg)
+   "Kernel-Version",   // NO_KEY: Used only by d-i
+   "Built-Using",
+   "Static-Built-Using",
+   "Built-For-Profiles",
+   "Auto-Built-Package",
+   "Multi-Arch",
+   "Status",
+   "Priority",
+// "Class", // Obsolete alias for Priority, warning by dpkg
+   "Build-Essential",
+   "Protected",
+   "Important", // old name of Protected
+   "Essential",
+   "Installer-Menu-Item", // NO_KEY: Used only by d-i
+   "Section",
+   "Source",
+   "Origin",
+   "Phased-Update-Percentage",
+   "Maintainer",
+   "Original-Maintainer", // unknown in dpkg order
+   "Bugs", // NO_KEY: very uncommon encounter
+   "Config-Version", // Internal of dpkg
+   "Conffiles",
+   "Triggers-Awaited", // NO_KEY: Internal of dpkg
+   "Triggers-Pending", // NO_KEY: Internal of dpkg
+   "Installed-Size",
+   "Provides",
+   "Pre-Depends",
+   "Depends",
+   "Recommends",
+// "Recommended", // Obsolete alias for Recommends, warning by dpkg
+   "Suggests",
+// "Optional", // Obsolete alias for Suggests, warning by dpkg
+   "Conflicts",
+   "Breaks",
+   "Replaces",
+   "Enhances",
+   "Filename",
+   "MSDOS-Filename", // NO_KEY: Obsolete (used by dselect)
+   "Size",
+   "MD5sum",
+   "SHA1",
+   "SHA256",
+   "SHA512",
+   "Homepage",
+   "Description",
+   "Description-md5",
+   "Tag",
+   "Task",
+   0,
+};
+static const char *iTFRewriteSourceOrder[] = {
+   "Package",
+   "Source", // dsc file, renamed to Package in Sources
+   "Format",
+   "Binary",
+   "Architecture",
+   "Version",
+   "Priority",
+// "Class", // Obsolete alias for Priority, warning by dpkg
+   "Section",
+   "Origin",
+   "Maintainer",
+   "Original-Maintainer", // unknown in dpkg order
+   "Uploaders",
+   "Dm-Upload-Allowed", // NO_KEY: Obsolete (ignored by dak)
+   "Standards-Version",
+   "Build-Depends",
+   "Build-Depends-Arch",
+   "Build-Depends-Indep",
+   "Build-Conflicts",
+   "Build-Conflicts-Arch",
+   "Build-Conflicts-Indep",
+   "Testsuite",
+   "Testsuite-Triggers",
+   "Homepage",
+   "Description",
+   "Vcs-Browser",
+   "Vcs-Browse", // NO_KEY: dak only (nickname?)
+   "Vcs-Arch",
+   "Vcs-Bzr",
+   "Vcs-Cvs",
+   "Vcs-Darcs",
+   "Vcs-Git",
+   "Vcs-Hg",
+   "Vcs-Mtn",
+   "Vcs-Svn",
+   "Directory",
+   "Package-List",
+   "Files",
+   "Checksums-Md5",
+   "Checksums-Sha1",
+   "Checksums-Sha256",
+   "Checksums-Sha512",
+   0,
+};
+
+/* Two levels of initialization are used because gcc will set the symbol
+   size of an array to the length of the array, causing dynamic relinking
+   errors. Doing this makes the symbol size constant */
+const char **TFRewritePackageOrder = iTFRewritePackageOrder;
+const char **TFRewriteSourceOrder = iTFRewriteSourceOrder;
diff --git a/apt-pkg/tagfile.cc b/apt-pkg/tagfile.cc
new file mode 100644
index 0000000..047f889
--- /dev/null
+++ b/apt-pkg/tagfile.cc
@@ -0,0 +1,1083 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Fast scanner for RFC-822 type header information
+   
+   This uses a rotating buffer to load the package information into.
+   The scanner runs over it and isolates and indexes a single section.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <list>
+
+#include <string>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+using APT::StringView;
+
+class APT_HIDDEN pkgTagFilePrivate					/*{{{*/
+{
+public:
+   void Reset(FileFd * const pFd, unsigned long long const pSize, pkgTagFile::Flags const pFlags)
+   {
+      if (Buffer != NULL)
+	 free(Buffer);
+      Buffer = NULL;
+      Fd = pFd;
+      Flags = pFlags;
+      Start = NULL;
+      End = NULL;
+      Done = false;
+      iOffset = 0;
+      Size = pSize;
+      isCommentedLine = false;
+      chunks.clear();
+   }
+
+   pkgTagFilePrivate(FileFd * const pFd, unsigned long long const Size, pkgTagFile::Flags const pFlags) : Buffer(NULL)
+   {
+      Reset(pFd, Size, pFlags);
+   }
+   FileFd * Fd;
+   pkgTagFile::Flags Flags;
+   char *Buffer;
+   char *Start;
+   char *End;
+   bool Done;
+   unsigned long long iOffset;
+   unsigned long long Size;
+   bool isCommentedLine;
+   struct FileChunk
+   {
+      bool const good;
+      size_t length;
+      FileChunk(bool const pgood, size_t const plength) noexcept : good(pgood), length(plength) {}
+   };
+   std::list<FileChunk> chunks;
+
+   ~pkgTagFilePrivate()
+   {
+      if (Buffer != NULL)
+	 free(Buffer);
+   }
+};
+									/*}}}*/
+class APT_HIDDEN pkgTagSectionPrivate					/*{{{*/
+{
+public:
+   pkgTagSectionPrivate()
+   {
+   }
+   struct TagData {
+      unsigned int StartTag;
+      unsigned int EndTag;
+      unsigned int StartValue;
+      unsigned int NextInBucket;
+
+      explicit TagData(unsigned int const StartTag) : StartTag(StartTag), EndTag(0), StartValue(0), NextInBucket(0) {}
+   };
+   std::vector<TagData> Tags;
+};
+									/*}}}*/
+
+static unsigned long BetaHash(const char *Text, size_t Length)		/*{{{*/
+{
+   /* This very simple hash function for the last 8 letters gives
+      very good performance on the debian package files */
+   if (Length > 8)
+   {
+    Text += (Length - 8);
+    Length = 8;
+   }
+   unsigned long Res = 0;
+   for (size_t i = 0; i < Length; ++i)
+      Res = ((unsigned long)(Text[i]) & 0xDF) ^ (Res << 1);
+   return Res & 0x7F;
+}
+									/*}}}*/
+
+// TagFile::pkgTagFile - Constructor					/*{{{*/
+pkgTagFile::pkgTagFile(FileFd * const pFd,pkgTagFile::Flags const pFlags, unsigned long long const Size)
+   : d(new pkgTagFilePrivate(pFd, Size + 4, pFlags))
+{
+   Init(pFd, pFlags, Size);
+}
+pkgTagFile::pkgTagFile(FileFd * const pFd,unsigned long long const Size)
+   : pkgTagFile(pFd, pkgTagFile::STRICT, Size)
+{
+}
+void pkgTagFile::Init(FileFd * const pFd, pkgTagFile::Flags const pFlags, unsigned long long Size)
+{
+   /* The size is increased by 4 because if we start with the Size of the
+      filename we need to try to read 1 char more to see an EOF faster, 1
+      char the end-pointer can be on and maybe 2 newlines need to be added
+      to the end of the file -> 4 extra chars */
+   Size += 4;
+   d->Reset(pFd, Size, pFlags);
+
+   if (d->Fd->IsOpen() == false)
+      d->Start = d->End = d->Buffer = 0;
+   else
+      d->Buffer = (char*)malloc(sizeof(char) * Size);
+
+   if (d->Buffer == NULL)
+      d->Done = true;
+   else
+      d->Done = false;
+
+   d->Start = d->End = d->Buffer;
+   d->iOffset = 0;
+   if (d->Done == false)
+      Fill();
+}
+void pkgTagFile::Init(FileFd * const pFd,unsigned long long Size)
+{
+   Init(pFd, pkgTagFile::STRICT, Size);
+}
+									/*}}}*/
+// TagFile::~pkgTagFile - Destructor					/*{{{*/
+pkgTagFile::~pkgTagFile()
+{
+   delete d;
+}
+									/*}}}*/
+// TagFile::Offset - Return the current offset in the buffer		/*{{{*/
+APT_PURE unsigned long pkgTagFile::Offset()
+{
+   return d->iOffset;
+}
+									/*}}}*/
+// TagFile::Resize - Resize the internal buffer				/*{{{*/
+// ---------------------------------------------------------------------
+/* Resize the internal buffer (double it in size). Fail if a maximum size
+ * size is reached.
+ */
+bool pkgTagFile::Resize()
+{
+   // fail is the buffer grows too big
+   if(d->Size > 1024*1024+1)
+      return false;
+
+   return Resize(d->Size * 2);
+}
+bool pkgTagFile::Resize(unsigned long long const newSize)
+{
+   unsigned long long const EndSize = d->End - d->Start;
+
+   // get new buffer and use it
+   char* const newBuffer = static_cast<char*>(realloc(d->Buffer, sizeof(char) * newSize));
+   if (newBuffer == NULL)
+      return false;
+   d->Buffer = newBuffer;
+   d->Size = newSize;
+
+   // update the start/end pointers to the new buffer
+   d->Start = d->Buffer;
+   d->End = d->Start + EndSize;
+   return true;
+}
+									/*}}}*/
+// TagFile::Step - Advance to the next section				/*{{{*/
+// ---------------------------------------------------------------------
+/* If the Section Scanner fails we refill the buffer and try again. 
+ * If that fails too, double the buffer size and try again until a
+ * maximum buffer is reached.
+ */
+bool pkgTagFile::Step(pkgTagSection &Tag)
+{
+   if(Tag.Scan(d->Start,d->End - d->Start) == false)
+   {
+      do
+      {
+	 if (Fill() == false)
+	    return false;
+
+	 if(Tag.Scan(d->Start,d->End - d->Start, false))
+	    break;
+
+	 if (Resize() == false)
+	    return _error->Error(_("Unable to parse package file %s (%d)"),
+		  d->Fd->Name().c_str(), 1);
+
+      } while (Tag.Scan(d->Start,d->End - d->Start, false) == false);
+   }
+
+   size_t tagSize = Tag.size();
+   d->Start += tagSize;
+
+   if ((d->Flags & pkgTagFile::SUPPORT_COMMENTS) == 0)
+      d->iOffset += tagSize;
+   else
+   {
+      auto first = d->chunks.begin();
+      for (; first != d->chunks.end(); ++first)
+      {
+	 if (first->good == false)
+	    d->iOffset += first->length;
+	 else
+	 {
+	    if (tagSize < first->length)
+	    {
+	       first->length -= tagSize;
+	       d->iOffset += tagSize;
+	       break;
+	    }
+	    else
+	    {
+	       tagSize -= first->length;
+	       d->iOffset += first->length;
+	    }
+	 }
+      }
+      d->chunks.erase(d->chunks.begin(), first);
+   }
+
+   if ((d->Flags & pkgTagFile::SUPPORT_COMMENTS) == 0 || Tag.Count() != 0)
+   {
+      Tag.Trim();
+      return true;
+   }
+   return Step(Tag);
+}
+									/*}}}*/
+// TagFile::Fill - Top up the buffer					/*{{{*/
+// ---------------------------------------------------------------------
+/* This takes the bit at the end of the buffer and puts it at the start
+   then fills the rest from the file */
+static bool FillBuffer(pkgTagFilePrivate * const d)
+{
+   unsigned long long Actual = 0;
+   // See if only a bit of the file is left
+   unsigned long long const dataSize = d->Size - ((d->End - d->Buffer) + 1);
+   if (d->Fd->Read(d->End, dataSize, &Actual) == false)
+      return false;
+   if (Actual != dataSize)
+      d->Done = true;
+   d->End += Actual;
+   return true;
+}
+static void RemoveCommentsFromBuffer(pkgTagFilePrivate * const d)
+{
+   // look for valid comments in the buffer
+   char * good_start = nullptr, * bad_start = nullptr;
+   char * current = d->Start;
+   if (d->isCommentedLine == false)
+   {
+      if (d->Start == d->Buffer)
+      {
+	 // the start of the buffer is a newline as a record can't start
+	 // in the middle of a line by definition.
+	 if (*d->Start == '#')
+	 {
+	    d->isCommentedLine = true;
+	    ++current;
+	    if (current > d->End)
+	       d->chunks.emplace_back(false, 1);
+	 }
+      }
+      if (d->isCommentedLine == false)
+	 good_start = d->Start;
+      else
+	 bad_start = d->Start;
+   }
+   else
+      bad_start = d->Start;
+
+   std::vector<std::pair<char*, size_t>> good_parts;
+   while (current <= d->End)
+   {
+      size_t const restLength = (d->End - current);
+      if (d->isCommentedLine == false)
+      {
+	 current = static_cast<char*>(memchr(current, '#', restLength));
+	 if (current == nullptr)
+	 {
+	    size_t const goodLength = d->End - good_start;
+	    d->chunks.emplace_back(true, goodLength);
+	    if (good_start != d->Start)
+	       good_parts.push_back(std::make_pair(good_start, goodLength));
+	    break;
+	 }
+	 bad_start = current;
+	 --current;
+	 // ensure that this is really a comment and not a '#' in the middle of a line
+	 if (*current == '\n')
+	 {
+	    size_t const goodLength = (current - good_start) + 1;
+	    d->chunks.emplace_back(true, goodLength);
+	    good_parts.push_back(std::make_pair(good_start, goodLength));
+	    good_start = nullptr;
+	    d->isCommentedLine = true;
+	 }
+	 current += 2;
+      }
+      else // the current line is a comment
+      {
+	 current = static_cast<char*>(memchr(current, '\n', restLength));
+	 if (current == nullptr)
+	 {
+	    d->chunks.emplace_back(false, (d->End - bad_start));
+	    break;
+	 }
+	 ++current;
+	 // is the next line a comment, too?
+	 if (current >= d->End || *current != '#')
+	 {
+	    d->chunks.emplace_back(false, (current - bad_start));
+	    good_start = current;
+	    bad_start = nullptr;
+	    d->isCommentedLine = false;
+	 }
+	 ++current;
+      }
+   }
+
+   if (good_parts.empty() == false)
+   {
+      // we found comments, so move later parts over them
+      current = d->Start;
+      for (auto const &good: good_parts)
+      {
+	 memmove(current, good.first, good.second);
+	 current += good.second;
+      }
+      d->End = current;
+   }
+
+   if (d->isCommentedLine == true)
+   {
+      // deal with a buffer containing only comments
+      // or an (unfinished) comment at the end
+      if (good_parts.empty() == true)
+	 d->End = d->Start;
+      else
+	 d->Start = d->End;
+   }
+   else
+   {
+      // the buffer was all comment, but ended with the buffer
+      if (good_parts.empty() == true && good_start >= d->End)
+	 d->End = d->Start;
+      else
+	 d->Start = d->End;
+   }
+}
+bool pkgTagFile::Fill()
+{
+   unsigned long long const EndSize = d->End - d->Start;
+   if (EndSize != 0)
+   {
+      memmove(d->Buffer,d->Start,EndSize);
+      d->Start = d->End = d->Buffer + EndSize;
+   }
+   else
+      d->Start = d->End = d->Buffer;
+
+   unsigned long long Actual = 0;
+   while (d->Done == false && d->Size > (Actual + 1))
+   {
+      if (FillBuffer(d) == false)
+	 return false;
+      if ((d->Flags & pkgTagFile::SUPPORT_COMMENTS) != 0)
+	 RemoveCommentsFromBuffer(d);
+      Actual = d->End - d->Buffer;
+   }
+   d->Start = d->Buffer;
+
+   if (d->Done == true)
+   {
+      if (EndSize <= 3 && Actual == 0)
+	 return false;
+      if (d->Size - (d->End - d->Buffer) < 4)
+	 return true;
+
+      // Append a double new line if one does not exist
+      unsigned int LineCount = 0;
+      for (const char *E = d->End - 1; E - d->End < 6 && (*E == '\n' || *E == '\r'); E--)
+	 if (*E == '\n')
+	    ++LineCount;
+      if (LineCount < 2)
+      {
+	 if (static_cast<unsigned long long>(d->End - d->Buffer) >= d->Size)
+	    Resize(d->Size + 3);
+	 for (; LineCount < 2; ++LineCount)
+	    *d->End++ = '\n';
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// TagFile::Jump - Jump to a pre-recorded location in the file		/*{{{*/
+// ---------------------------------------------------------------------
+/* This jumps to a pre-recorded file location and reads the record
+   that is there */
+bool pkgTagFile::Jump(pkgTagSection &Tag,unsigned long long Offset)
+{
+   if ((d->Flags & pkgTagFile::SUPPORT_COMMENTS) == 0 &&
+   // We are within a buffer space of the next hit..
+	 Offset >= d->iOffset && d->iOffset + (d->End - d->Start) > Offset)
+   {
+      unsigned long long Dist = Offset - d->iOffset;
+      d->Start += Dist;
+      d->iOffset += Dist;
+      // if we have seen the end, don't ask for more
+      if (d->Done == true)
+	 return Tag.Scan(d->Start, d->End - d->Start);
+      else
+	 return Step(Tag);
+   }
+
+   // Reposition and reload..
+   d->iOffset = Offset;
+   d->Done = false;
+   if (d->Fd->Seek(Offset) == false)
+      return false;
+   d->End = d->Start = d->Buffer;
+   d->isCommentedLine = false;
+   d->chunks.clear();
+
+   if (Fill() == false)
+      return false;
+
+   if (Tag.Scan(d->Start, d->End - d->Start) == true)
+      return true;
+   
+   // This appends a double new line (for the real eof handling)
+   if (Fill() == false)
+      return false;
+   
+   if (Tag.Scan(d->Start, d->End - d->Start, false) == false)
+      return _error->Error(_("Unable to parse package file %s (%d)"),d->Fd->Name().c_str(), 2);
+   
+   return true;
+}
+									/*}}}*/
+// pkgTagSection::pkgTagSection - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgTagSection::pkgTagSection()
+   : Section(0), d(new pkgTagSectionPrivate()), Stop(0)
+{
+   memset(&AlphaIndexes, 0, sizeof(AlphaIndexes));
+   memset(&BetaIndexes, 0, sizeof(BetaIndexes));
+}
+									/*}}}*/
+// TagSection::Scan - Scan for the end of the header information	/*{{{*/
+bool pkgTagSection::Scan(const char *Start,unsigned long MaxLength, bool const Restart)
+{
+   Section = Start;
+   const char *End = Start + MaxLength;
+
+   if (Restart == false && d->Tags.empty() == false)
+   {
+      Stop = Section + d->Tags.back().StartTag;
+      if (End <= Stop)
+	 return false;
+      Stop = (const char *)memchr(Stop,'\n',End - Stop);
+      if (Stop == NULL)
+	 return false;
+      ++Stop;
+   }
+   else
+   {
+      Stop = Section;
+      if (d->Tags.empty() == false)
+      {
+	 memset(&AlphaIndexes, 0, sizeof(AlphaIndexes));
+	 memset(&BetaIndexes, 0, sizeof(BetaIndexes));
+	 d->Tags.clear();
+      }
+      d->Tags.reserve(0x100);
+   }
+   unsigned int TagCount = d->Tags.size();
+
+   if (Stop == 0)
+      return false;
+
+   pkgTagSectionPrivate::TagData lastTagData(0);
+   Key lastTagKey = Key::Unknown;
+   unsigned int lastTagHash = 0;
+   while (Stop < End)
+   {
+      TrimRecord(true,End);
+
+      // this can happen when TrimRecord trims away the entire Record
+      // (e.g. because it just contains comments)
+      if(Stop == End)
+         return true;
+
+      // Start a new index and add it to the hash
+      if (isspace_ascii(Stop[0]) == 0)
+      {
+	 // store the last found tag
+	 if (lastTagData.StartValue != 0)
+	 {
+	    if (lastTagKey != Key::Unknown) {
+	       AlphaIndexes[static_cast<size_t>(lastTagKey)] = TagCount;
+	    } else {
+	       if (BetaIndexes[lastTagHash] != 0)
+		  lastTagData.NextInBucket = BetaIndexes[lastTagHash];
+	       BetaIndexes[lastTagHash] = TagCount;
+	    }
+	    d->Tags.push_back(lastTagData);
+	 }
+
+	 ++TagCount;
+	 lastTagData = pkgTagSectionPrivate::TagData(Stop - Section);
+	 // find the colon separating tag and value
+	 char const * Colon = (char const *) memchr(Stop, ':', End - Stop);
+	 if (Colon == NULL)
+	    return false;
+	 // find the end of the tag (which might or might not be the colon)
+	 char const * EndTag = Colon;
+	 --EndTag;
+	 for (; EndTag > Stop && isspace_ascii(*EndTag) != 0; --EndTag)
+	    ;
+	 ++EndTag;
+	 lastTagData.EndTag = EndTag - Section;
+	 lastTagKey = pkgTagHash(Stop, EndTag - Stop);
+	 if (lastTagKey == Key::Unknown)
+	    lastTagHash = BetaHash(Stop, EndTag - Stop);
+	 // find the beginning of the value
+	 Stop = Colon + 1;
+	 for (; Stop < End && isspace_ascii(*Stop) != 0; ++Stop)
+	    if (*Stop == '\n' && Stop[1] != ' ')
+	       break;
+	 if (Stop >= End)
+	    return false;
+	 lastTagData.StartValue = Stop - Section;
+      }
+
+      Stop = (const char *)memchr(Stop,'\n',End - Stop);
+
+      if (Stop == 0)
+	 return false;
+
+      for (; Stop+1 < End && Stop[1] == '\r'; Stop++)
+         /* nothing */
+         ;
+
+      // Double newline marks the end of the record
+      if (Stop+1 < End && Stop[1] == '\n')
+      {
+	 if (lastTagData.StartValue != 0)
+	 {
+	    if (lastTagKey != Key::Unknown) {
+	       AlphaIndexes[static_cast<size_t>(lastTagKey)] = TagCount;
+	    } else {
+	       if (BetaIndexes[lastTagHash] != 0)
+		  lastTagData.NextInBucket = BetaIndexes[lastTagHash];
+	       BetaIndexes[lastTagHash] = TagCount;
+	    }
+	    d->Tags.push_back(lastTagData);
+	 }
+
+	 pkgTagSectionPrivate::TagData const td(Stop - Section);
+	 d->Tags.push_back(td);
+	 TrimRecord(false,End);
+	 return true;
+      }
+      
+      Stop++;
+   }
+
+   return false;
+}
+									/*}}}*/
+// TagSection::TrimRecord - Trim off any garbage before/after a record	/*{{{*/
+// ---------------------------------------------------------------------
+/* There should be exactly 2 newline at the end of the record, no more. */
+void pkgTagSection::TrimRecord(bool BeforeRecord, const char*& End)
+{
+   if (BeforeRecord == true)
+      return;
+   for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r'); Stop++);
+}
+									/*}}}*/
+// TagSection::Trim - Trim off any trailing garbage			/*{{{*/
+// ---------------------------------------------------------------------
+/* There should be exactly 1 newline at the end of the buffer, no more. */
+void pkgTagSection::Trim()
+{
+   for (; Stop > Section + 2 && (Stop[-2] == '\n' || Stop[-2] == '\r'); Stop--);
+}
+									/*}}}*/
+// TagSection::Exists - return True if a tag exists			/*{{{*/
+bool pkgTagSection::Exists(StringView Tag) const
+{
+   unsigned int tmp;
+   return Find(Tag, tmp);
+}
+bool pkgTagSection::Exists(Key key) const
+{
+   unsigned int tmp;
+   return Find(key, tmp);
+}
+									/*}}}*/
+// TagSection::Find - Locate a tag					/*{{{*/
+// ---------------------------------------------------------------------
+/* This searches the section for a tag that matches the given string. */
+bool pkgTagSection::Find(Key key,unsigned int &Pos) const
+{
+   auto Bucket = AlphaIndexes[static_cast<size_t>(key)];
+   Pos = Bucket - 1;
+   return Bucket != 0;
+}
+bool pkgTagSection::Find(StringView TagView,unsigned int &Pos) const
+{
+   const char * const Tag = TagView.data();
+   size_t const Length = TagView.length();
+   auto key = pkgTagHash(Tag, Length);
+   if (key != Key::Unknown)
+      return Find(key, Pos);
+
+   unsigned int Bucket = BetaIndexes[BetaHash(Tag, Length)];
+   if (Bucket == 0)
+      return false;
+
+   for (; Bucket != 0; Bucket = d->Tags[Bucket - 1].NextInBucket)
+   {
+      if ((d->Tags[Bucket - 1].EndTag - d->Tags[Bucket - 1].StartTag) != Length)
+	 continue;
+
+      char const * const St = Section + d->Tags[Bucket - 1].StartTag;
+      if (strncasecmp(Tag,St,Length) != 0)
+	 continue;
+
+      Pos = Bucket - 1;
+      return true;
+   }
+
+   Pos = 0;
+   return false;
+}
+
+bool pkgTagSection::FindInternal(unsigned int Pos, const char *&Start,
+		         const char *&End) const
+{
+   if (unlikely(Pos + 1 >= d->Tags.size() || Pos >= d->Tags.size()))
+      return _error->Error("Internal parsing error");
+
+   Start = Section + d->Tags[Pos].StartValue;
+   // Strip off the gunk from the end
+   End = Section + d->Tags[Pos + 1].StartTag;
+   if (unlikely(Start > End))
+      return _error->Error("Internal parsing error");
+
+   for (; isspace_ascii(End[-1]) != 0 && End > Start; --End);
+
+   return true;
+}
+bool pkgTagSection::Find(StringView Tag,const char *&Start,
+		         const char *&End) const
+{
+   unsigned int Pos;
+   return Find(Tag, Pos) && FindInternal(Pos, Start, End);
+}
+bool pkgTagSection::Find(Key key,const char *&Start,
+		         const char *&End) const
+{
+   unsigned int Pos;
+   return Find(key, Pos) && FindInternal(Pos, Start, End);
+}
+									/*}}}*/
+// TagSection::FindS - Find a string					/*{{{*/
+StringView pkgTagSection::Find(StringView Tag) const
+{
+   const char *Start;
+   const char *End;
+   if (Find(Tag,Start,End) == false)
+      return StringView();
+   return StringView(Start, End - Start);
+}
+StringView pkgTagSection::Find(Key key) const
+{
+   const char *Start;
+   const char *End;
+   if (Find(key,Start,End) == false)
+      return StringView();
+   return StringView(Start, End - Start);
+}
+									/*}}}*/
+// TagSection::FindRawS - Find a string					/*{{{*/
+StringView pkgTagSection::FindRawInternal(unsigned int Pos) const
+{
+   if (unlikely(Pos + 1 >= d->Tags.size() || Pos >= d->Tags.size()))
+      return _error->Error("Internal parsing error"), "";
+
+   char const *Start = (char const *) memchr(Section + d->Tags[Pos].EndTag, ':', d->Tags[Pos].StartValue - d->Tags[Pos].EndTag);
+   char const *End = Section + d->Tags[Pos + 1].StartTag;
+
+   if (Start == nullptr)
+      return "";
+
+   ++Start;
+
+   if (unlikely(Start > End))
+      return "";
+
+   for (; isspace_ascii(End[-1]) != 0 && End > Start; --End);
+
+   return StringView(Start, End - Start);
+}
+StringView pkgTagSection::FindRaw(StringView Tag) const
+{
+   unsigned int Pos;
+   return Find(Tag, Pos) ? FindRawInternal(Pos) : "";
+}
+StringView pkgTagSection::FindRaw(Key key) const
+{
+   unsigned int Pos;
+   return Find(key, Pos) ? FindRawInternal(Pos) : "";
+}
+									/*}}}*/
+// TagSection::FindI - Find an integer					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+signed int pkgTagSection::FindIInternal(unsigned int Pos,signed long Default) const
+{
+   const char *Start;
+   const char *Stop;
+   if (FindInternal(Pos,Start,Stop) == false)
+      return Default;
+
+   // Copy it into a temp buffer so we can use strtol
+   char S[300];
+   if ((unsigned)(Stop - Start) >= sizeof(S))
+      return Default;
+   strncpy(S,Start,Stop-Start);
+   S[Stop - Start] = 0;
+
+   errno = 0;
+   char *End;
+   signed long Result = strtol(S,&End,10);
+   if (errno == ERANGE ||
+       Result < std::numeric_limits<int>::min() || Result > std::numeric_limits<int>::max()) {
+      errno = ERANGE;
+      _error->Error(_("Cannot convert %s to integer: out of range"), S);
+   }
+   if (S == End)
+      return Default;
+   return Result;
+}
+signed int pkgTagSection::FindI(Key key,signed long Default) const
+{
+   unsigned int Pos;
+
+   return Find(key, Pos) ? FindIInternal(Pos) : Default;
+}
+signed int pkgTagSection::FindI(StringView Tag,signed long Default) const
+{
+   unsigned int Pos;
+
+   return Find(Tag, Pos) ? FindIInternal(Pos, Default) : Default;
+}
+									/*}}}*/
+// TagSection::FindULL - Find an unsigned long long integer		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned long long pkgTagSection::FindULLInternal(unsigned int Pos, unsigned long long const &Default) const
+{
+   const char *Start;
+   const char *Stop;
+   if (FindInternal(Pos,Start,Stop) == false)
+      return Default;
+
+   // Copy it into a temp buffer so we can use strtoull
+   char S[100];
+   if ((unsigned)(Stop - Start) >= sizeof(S))
+      return Default;
+   strncpy(S,Start,Stop-Start);
+   S[Stop - Start] = 0;
+   
+   char *End;
+   unsigned long long Result = strtoull(S,&End,10);
+   if (S == End)
+      return Default;
+   return Result;
+}
+unsigned long long pkgTagSection::FindULL(Key key, unsigned long long const &Default) const
+{
+   unsigned int Pos;
+
+   return Find(key, Pos) ? FindULLInternal(Pos, Default) : Default;
+}
+unsigned long long pkgTagSection::FindULL(StringView Tag, unsigned long long const &Default) const
+{
+   unsigned int Pos;
+
+   return Find(Tag, Pos) ? FindULLInternal(Pos, Default) : Default;
+}
+									/*}}}*/
+// TagSection::FindB - Find boolean value                		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgTagSection::FindBInternal(unsigned int Pos, bool Default) const
+{
+   const char *Start, *Stop;
+   if (FindInternal(Pos, Start, Stop) == false)
+      return Default;
+   return StringToBool(string(Start, Stop));
+}
+bool pkgTagSection::FindB(Key key, bool Default) const
+{
+   unsigned int Pos;
+   return Find(key, Pos) ? FindBInternal(Pos, Default): Default;
+}
+bool pkgTagSection::FindB(StringView Tag, bool Default) const
+{
+   unsigned int Pos;
+   return Find(Tag, Pos) ? FindBInternal(Pos, Default) : Default;
+}
+									/*}}}*/
+// TagSection::FindFlag - Locate a yes/no type flag			/*{{{*/
+// ---------------------------------------------------------------------
+/* The bits marked in Flag are masked on/off in Flags */
+bool pkgTagSection::FindFlagInternal(unsigned int Pos, uint8_t &Flags,
+			     uint8_t const Flag) const
+{
+   const char *Start;
+   const char *Stop;
+   if (FindInternal(Pos,Start,Stop) == false)
+      return true;
+   return FindFlag(Flags, Flag, Start, Stop);
+}
+bool pkgTagSection::FindFlag(Key key, uint8_t &Flags,
+			     uint8_t const Flag) const
+{
+   unsigned int Pos;
+   if (Find(key,Pos) == false)
+      return true;
+   return FindFlagInternal(Pos, Flags, Flag);
+}
+bool pkgTagSection::FindFlag(StringView Tag, uint8_t &Flags,
+			     uint8_t const Flag) const
+{
+   unsigned int Pos;
+   if (Find(Tag,Pos) == false)
+      return true;
+   return FindFlagInternal(Pos, Flags, Flag);
+}
+bool pkgTagSection::FindFlag(uint8_t &Flags, uint8_t const Flag,
+					char const* const Start, char const* const Stop)
+{
+   switch (StringToBool(string(Start, Stop)))
+   {
+      case 0:
+      Flags &= ~Flag;
+      return true;
+
+      case 1:
+      Flags |= Flag;
+      return true;
+
+      default:
+      _error->Warning("Unknown flag value: %s",string(Start,Stop).c_str());
+      return true;
+   }
+   return true;
+}
+bool pkgTagSection::FindFlagInternal(unsigned int Pos,unsigned long &Flags,
+			     unsigned long Flag) const
+{
+   const char *Start;
+   const char *Stop;
+   if (FindInternal(Pos,Start,Stop) == false)
+      return true;
+   return FindFlag(Flags, Flag, Start, Stop);
+}
+bool pkgTagSection::FindFlag(Key key,unsigned long &Flags,
+			     unsigned long Flag) const
+{
+   unsigned int Pos;
+   return Find(key, Pos) ? FindFlagInternal(Pos, Flags, Flag) : true;
+}
+bool pkgTagSection::FindFlag(StringView Tag,unsigned long &Flags,
+			     unsigned long Flag) const
+{
+   unsigned int Pos;
+   return Find(Tag, Pos) ? FindFlagInternal(Pos, Flags, Flag) : true;
+}
+bool pkgTagSection::FindFlag(unsigned long &Flags, unsigned long Flag,
+					char const* Start, char const* Stop)
+{
+   switch (StringToBool(string(Start, Stop)))
+   {
+      case 0:
+      Flags &= ~Flag;
+      return true;
+
+      case 1:
+      Flags |= Flag;
+      return true;
+
+      default:
+      _error->Warning("Unknown flag value: %s",string(Start,Stop).c_str());
+      return true;
+   }
+   return true;
+}
+									/*}}}*/
+void pkgTagSection::Get(const char *&Start,const char *&Stop,unsigned int I) const/*{{{*/
+{
+   if (unlikely(I + 1 >= d->Tags.size() || I >= d->Tags.size()))
+      abort();
+   Start = Section + d->Tags[I].StartTag;
+   Stop = Section + d->Tags[I+1].StartTag;
+}
+									/*}}}*/
+APT_PURE unsigned int pkgTagSection::Count() const {			/*{{{*/
+   if (d->Tags.empty() == true)
+      return 0;
+   // the last element is just marking the end and isn't a real one
+   return d->Tags.size() - 1;
+}
+									/*}}}*/
+// TagSection::Write - Ordered (re)writing of fields			/*{{{*/
+pkgTagSection::Tag pkgTagSection::Tag::Remove(std::string const &Name)
+{
+   return Tag(REMOVE, Name, "");
+}
+pkgTagSection::Tag pkgTagSection::Tag::Rename(std::string const &OldName, std::string const &NewName)
+{
+   return Tag(RENAME, OldName, NewName);
+}
+pkgTagSection::Tag pkgTagSection::Tag::Rewrite(std::string const &Name, std::string const &Data)
+{
+   if (Data.empty() == true)
+      return Tag(REMOVE, Name, "");
+   else
+      return Tag(REWRITE, Name, Data);
+}
+static bool WriteTag(FileFd &File, std::string Tag, StringView Value)
+{
+   if (Value.empty() || isspace_ascii(Value[0]) != 0)
+      Tag.append(":");
+   else
+      Tag.append(": ");
+   Tag.append(Value.data(), Value.length());
+   Tag.append("\n");
+   return File.Write(Tag.c_str(), Tag.length());
+}
+static bool RewriteTags(FileFd &File, pkgTagSection const * const This, char const * const Tag,
+      std::vector<pkgTagSection::Tag>::const_iterator &R,
+      std::vector<pkgTagSection::Tag>::const_iterator const &REnd)
+{
+   size_t const TagLen = strlen(Tag);
+   for (; R != REnd; ++R)
+   {
+      std::string data;
+      if (R->Name.length() == TagLen && strncasecmp(R->Name.c_str(), Tag, R->Name.length()) == 0)
+      {
+	 if (R->Action != pkgTagSection::Tag::REWRITE)
+	    break;
+	 data = R->Data;
+      }
+      else if(R->Action == pkgTagSection::Tag::RENAME && R->Data.length() == TagLen &&
+	    strncasecmp(R->Data.c_str(), Tag, R->Data.length()) == 0)
+	 data = This->FindRaw(R->Name.c_str()).to_string();
+      else
+	 continue;
+
+      return WriteTag(File, Tag, data);
+   }
+   return true;
+}
+bool pkgTagSection::Write(FileFd &File, char const * const * const Order, std::vector<Tag> const &Rewrite) const
+{
+   // first pass: Write everything we have an order for
+   if (Order != NULL)
+   {
+      for (unsigned int I = 0; Order[I] != 0; ++I)
+      {
+	 std::vector<Tag>::const_iterator R = Rewrite.begin();
+	 if (RewriteTags(File, this, Order[I], R, Rewrite.end()) == false)
+	    return false;
+	 if (R != Rewrite.end())
+	    continue;
+
+	 if (Exists(Order[I]) == false)
+	    continue;
+
+	 if (WriteTag(File, Order[I], FindRaw(Order[I])) == false)
+	    return false;
+      }
+   }
+   // second pass: See if we have tags which aren't ordered
+   if (d->Tags.empty() == false)
+   {
+      for (std::vector<pkgTagSectionPrivate::TagData>::const_iterator T = d->Tags.begin(); T != d->Tags.end() - 1; ++T)
+      {
+	 char const * const fieldname = Section + T->StartTag;
+	 size_t fieldnamelen = T->EndTag - T->StartTag;
+	 if (Order != NULL)
+	 {
+	    unsigned int I = 0;
+	    for (; Order[I] != 0; ++I)
+	    {
+	       if (fieldnamelen == strlen(Order[I]) && strncasecmp(fieldname, Order[I], fieldnamelen) == 0)
+		  break;
+	    }
+	    if (Order[I] != 0)
+	       continue;
+	 }
+
+	 std::string const name(fieldname, fieldnamelen);
+	 std::vector<Tag>::const_iterator R = Rewrite.begin();
+	 if (RewriteTags(File, this, name.c_str(), R, Rewrite.end()) == false)
+	    return false;
+	 if (R != Rewrite.end())
+	    continue;
+
+	 if (WriteTag(File, name, FindRaw(name)) == false)
+	    return false;
+      }
+   }
+   // last pass: see if there are any rewrites remaining we haven't done yet
+   for (std::vector<Tag>::const_iterator R = Rewrite.begin(); R != Rewrite.end(); ++R)
+   {
+      if (R->Action == Tag::REMOVE)
+	 continue;
+      auto const name = ((R->Action == Tag::RENAME) ? R->Data : R->Name);
+      if (Exists(name))
+	 continue;
+      if (Order != NULL)
+      {
+	 unsigned int I = 0;
+	 for (; Order[I] != 0; ++I)
+	 {
+	    if (strncasecmp(name.c_str(), Order[I], name.length()) == 0 && name.length() == strlen(Order[I]))
+	       break;
+	 }
+	 if (Order[I] != 0)
+	    continue;
+      }
+
+      if (WriteTag(File, name, ((R->Action == Tag::RENAME) ? FindRaw(R->Name) : R->Data)) == false)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+
+#include "tagfile-order.c"
+
+pkgTagSection::~pkgTagSection() { delete d; }
diff --git a/apt-pkg/tagfile.h b/apt-pkg/tagfile.h
new file mode 100644
index 0000000..a9f5814
--- /dev/null
+++ b/apt-pkg/tagfile.h
@@ -0,0 +1,207 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Fast scanner for RFC-822 type header information
+   
+   This parser handles Debian package files (and others). Their form is
+   RFC-822 type header fields in groups separated by a blank line.
+   
+   The parser reads the file and provides methods to step linearly
+   over it or to jump to a pre-recorded start point and read that record.
+   
+   A second class is used to perform pre-parsing of the record. It works
+   by indexing the start of each header field and providing lookup 
+   functions for header fields.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_TAGFILE_H
+#define PKGLIB_TAGFILE_H
+
+#include <apt-pkg/macros.h>
+
+#include <stdint.h>
+#include <stdio.h>
+
+#include <list>
+#include <string>
+#include <vector>
+#include <apt-pkg/string_view.h>
+
+
+class FileFd;
+class pkgTagSectionPrivate;
+class pkgTagFilePrivate;
+
+/** \class pkgTagSection parses a single deb822 stanza and provides various Find methods
+ * to extract the included values. It can also be used to modify and write a
+ * valid deb822 stanza optionally (re)ordering the fields inside the stanza.
+ *
+ * Beware: This class does \b NOT support (#-)comments in in- or output!
+ * If the input contains comments they have to be stripped first like pkgTagFile
+ * does with SUPPORT_COMMENTS flag set. */
+class APT_PUBLIC pkgTagSection
+{
+   const char *Section;
+   unsigned int AlphaIndexes[128];
+   unsigned int BetaIndexes[128];
+
+   pkgTagSectionPrivate * const d;
+
+   APT_HIDDEN bool FindInternal(unsigned int Pos,const char *&Start, const char *&End) const;
+   APT_HIDDEN APT::StringView FindInternal(unsigned int Pos) const;
+   APT_HIDDEN APT::StringView FindRawInternal(unsigned int Pos) const;
+   APT_HIDDEN signed int FindIInternal(unsigned int Pos,signed long Default = 0) const;
+   APT_HIDDEN bool FindBInternal(unsigned int Pos, bool Default = false) const;
+   APT_HIDDEN unsigned long long FindULLInternal(unsigned int Pos, unsigned long long const &Default = 0) const;
+   APT_HIDDEN bool FindFlagInternal(unsigned int Pos,uint8_t &Flags, uint8_t const Flag) const;
+   APT_HIDDEN bool FindFlagInternal(unsigned int Pos,unsigned long &Flags, unsigned long Flag) const;
+
+   protected:
+   const char *Stop;
+
+   public:
+
+   inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
+   inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
+
+   // TODO: Remove internally
+   std::string FindS(APT::StringView sv) const { return Find(sv).to_string(); }
+   std::string FindRawS(APT::StringView sv) const { return FindRaw(sv).to_string(); };
+
+   // Functions for lookup with a perfect hash function
+   enum class Key;
+#ifdef APT_COMPILING_APT
+   bool Find(Key key,const char *&Start, const char *&End) const;
+   bool Find(Key key,unsigned int &Pos) const;
+   signed int FindI(Key key,signed long Default = 0) const;
+   bool FindB(Key key, bool Default = false) const;
+   unsigned long long FindULL(Key key, unsigned long long const &Default = 0) const;
+   bool FindFlag(Key key,uint8_t &Flags, uint8_t const Flag) const;
+   bool FindFlag(Key key,unsigned long &Flags, unsigned long Flag) const;
+   bool Exists(Key key) const;
+   APT::StringView Find(Key key) const;
+   APT::StringView FindRaw(Key key) const;
+#endif
+
+   bool Find(APT::StringView Tag,const char *&Start, const char *&End) const;
+   bool Find(APT::StringView Tag,unsigned int &Pos) const;
+   APT::StringView Find(APT::StringView Tag) const;
+   APT::StringView FindRaw(APT::StringView Tag) const;
+   signed int FindI(APT::StringView Tag,signed long Default = 0) const;
+   bool FindB(APT::StringView, bool Default = false) const;
+   unsigned long long FindULL(APT::StringView Tag, unsigned long long const &Default = 0) const;
+
+   bool FindFlag(APT::StringView Tag,uint8_t &Flags,
+		 uint8_t const Flag) const;
+   bool FindFlag(APT::StringView Tag,unsigned long &Flags,
+		 unsigned long Flag) const;
+   bool Exists(APT::StringView Tag) const;
+
+   bool static FindFlag(uint8_t &Flags, uint8_t const Flag,
+				const char* const Start, const char* const Stop);
+   bool static FindFlag(unsigned long &Flags, unsigned long Flag,
+				const char* Start, const char* Stop);
+
+   /** \brief searches the boundaries of the current section
+    *
+    * While parameter Start marks the beginning of the section, this method
+    * will search for the first double newline in the data stream which marks
+    * the end of the section. It also does a first pass over the content of
+    * the section parsing it as encountered for processing later on by Find
+    *
+    * @param Start is the beginning of the section
+    * @param MaxLength is the size of valid data in the stream pointed to by Start
+    * @param Restart if enabled internal state will be cleared, otherwise it is
+    *  assumed that now more data is available in the stream and the parsing will
+    *  start were it encountered insufficient data the last time.
+    *
+    * @return \b true if section end was found, \b false otherwise.
+    *  Beware that internal state will be inconsistent if \b false is returned!
+    */
+   APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart = true);
+
+   inline unsigned long size() const {return Stop - Section;};
+   void Trim();
+   virtual void TrimRecord(bool BeforeRecord, const char* &End);
+
+   /** \brief amount of Tags in the current section
+    *
+    * Note: if a Tag is mentioned repeatedly it will be counted multiple
+    * times, but only the last occurrence is available via Find methods.
+    */
+   unsigned int Count() const;
+
+   void Get(const char *&Start,const char *&Stop,unsigned int I) const;
+
+   inline void GetSection(const char *&Start,const char *&Stop) const
+   {
+      Start = Section;
+      Stop = this->Stop;
+   };
+
+   pkgTagSection();
+   virtual ~pkgTagSection();
+
+   struct Tag
+   {
+      enum ActionType { REMOVE, RENAME, REWRITE } Action;
+      std::string Name;
+      std::string Data;
+
+      static Tag Remove(std::string const &Name);
+      static Tag Rename(std::string const &OldName, std::string const &NewName);
+      static Tag Rewrite(std::string const &Name, std::string const &Data);
+      private:
+      Tag(ActionType const Action, std::string const &Name, std::string const &Data) :
+	 Action(Action), Name(Name), Data(Data) {}
+   };
+
+   /** Write this section (with optional rewrites) to a file
+    *
+    * @param File to write the section to
+    * @param Order in which tags should appear in the file
+    * @param Rewrite is a set of tags to be renamed, rewritten and/or removed
+    * @return \b true if successful, otherwise \b false
+    */
+   bool Write(FileFd &File, char const * const * const Order = NULL, std::vector<Tag> const &Rewrite = std::vector<Tag>()) const;
+};
+
+
+/** \class pkgTagFile reads and prepares a deb822 formatted file for parsing
+ * via #pkgTagSection. The default mode tries to be as fast as possible and
+ * assumes perfectly valid (machine generated) files like Packages. Support
+ * for comments e.g. needs to be enabled explicitly. */
+class APT_PUBLIC pkgTagFile
+{
+   pkgTagFilePrivate * const d;
+
+   APT_HIDDEN bool Fill();
+   APT_HIDDEN bool Resize();
+   APT_HIDDEN bool Resize(unsigned long long const newSize);
+
+public:
+
+   bool Step(pkgTagSection &Section);
+   unsigned long Offset();
+   bool Jump(pkgTagSection &Tag,unsigned long long Offset);
+
+   enum Flags
+   {
+      STRICT = 0,
+      SUPPORT_COMMENTS = 1 << 0,
+   };
+
+   void Init(FileFd * const F, pkgTagFile::Flags const Flags, unsigned long long Size = 32*1024);
+   void Init(FileFd * const F,unsigned long long const Size = 32*1024);
+
+   pkgTagFile(FileFd * const F, pkgTagFile::Flags const Flags, unsigned long long Size = 32*1024);
+   pkgTagFile(FileFd * const F,unsigned long long Size = 32*1024);
+   virtual ~pkgTagFile();
+};
+
+APT_PUBLIC extern const char **TFRewritePackageOrder;
+APT_PUBLIC extern const char **TFRewriteSourceOrder;
+
+#endif
diff --git a/apt-pkg/update.cc b/apt-pkg/update.cc
new file mode 100644
index 0000000..1bf818a
--- /dev/null
+++ b/apt-pkg/update.cc
@@ -0,0 +1,152 @@
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/acquire-item.h>
+#include <apt-pkg/acquire.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/sourcelist.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/update.h>
+
+#include <string>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// ListUpdate - construct Fetcher and update the cache files		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a simple wrapper to update the cache. it will fetch stuff
+ * from the network (or any other sources defined in sources.list)
+ */
+bool ListUpdate(pkgAcquireStatus &Stat, 
+		pkgSourceList &List, 
+		int PulseInterval)
+{
+   pkgAcquire Fetcher(&Stat);
+   if (Fetcher.GetLock(_config->FindDir("Dir::State::Lists")) == false)
+      return false;
+
+   // Populate it with the source selection
+   if (List.GetIndexes(&Fetcher) == false)
+	 return false;
+
+   return AcquireUpdate(Fetcher, PulseInterval, true);
+}
+									/*}}}*/
+// AcquireUpdate - take Fetcher and update the cache files		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a simple wrapper to update the cache with a provided acquire
+ * If you only need control over Status and the used SourcesList use
+ * ListUpdate method instead.
+ */
+bool AcquireUpdate(pkgAcquire &Fetcher, int const PulseInterval,
+		   bool const RunUpdateScripts, bool const ListCleanup)
+{
+   enum class ErrorMode
+   {
+      Persistent,
+      Any
+   };
+   std::string errorModeS = _config->Find("APT::Update::Error-Mode", "persistent");
+   ErrorMode errorMode = ErrorMode::Persistent;
+   if (errorModeS == "persistent")
+      errorMode = ErrorMode::Persistent;
+   else if (errorModeS == "any")
+      errorMode = ErrorMode::Any;
+   else
+      return _error->Error("Unknown update error mode %s", errorModeS.c_str());
+
+   // Run scripts
+   if (RunUpdateScripts == true)
+      RunScripts("APT::Update::Pre-Invoke");
+
+   pkgAcquire::RunResult res;
+   if(PulseInterval > 0)
+      res = Fetcher.Run(PulseInterval);
+   else
+      res = Fetcher.Run();
+
+   bool const errorsWereReported = (res == pkgAcquire::Failed);
+   bool Failed = errorsWereReported;
+   bool TransientNetworkFailure = false;
+   bool AllFailed = true;
+   for (pkgAcquire::ItemIterator I = Fetcher.ItemsBegin(); 
+	I != Fetcher.ItemsEnd(); ++I)
+   {
+      switch ((*I)->Status)
+      {
+	 case pkgAcquire::Item::StatDone:
+	    AllFailed = false;
+	    continue;
+	 case pkgAcquire::Item::StatTransientNetworkError:
+	    if (errorMode == ErrorMode::Any)
+	       Failed = true;
+	    else
+	       TransientNetworkFailure = true;
+	    break;
+	 case pkgAcquire::Item::StatIdle:
+	 case pkgAcquire::Item::StatFetching:
+	 case pkgAcquire::Item::StatError:
+	 case pkgAcquire::Item::StatAuthError:
+	    Failed = true;
+	    break;
+      }
+
+      (*I)->Finished();
+
+      if (errorsWereReported)
+	 continue;
+
+      ::URI uri((*I)->DescURI());
+      uri.User.clear();
+      uri.Password.clear();
+      if ((*I)->Local)
+	 uri.Path = DeQuoteString(uri.Path);
+      std::string const descUri = std::string(uri);
+      // Show an error for non-transient failures, otherwise only warn
+      if ((*I)->Status == pkgAcquire::Item::StatTransientNetworkError && errorMode != ErrorMode::Any)
+	 _error->Warning(_("Failed to fetch %s  %s"), descUri.c_str(),
+			(*I)->ErrorText.c_str());
+      else
+	 _error->Error(_("Failed to fetch %s  %s"), descUri.c_str(),
+	       (*I)->ErrorText.c_str());
+   }
+
+   // Clean out any old list files
+   // Keep "APT::Get::List-Cleanup" name for compatibility, but
+   // this is really a global option for the APT library now
+   if (!TransientNetworkFailure && !Failed && ListCleanup == true &&
+       (_config->FindB("APT::Get::List-Cleanup",true) == true &&
+	_config->FindB("APT::List-Cleanup",true) == true))
+   {
+      if (Fetcher.Clean(_config->FindDir("Dir::State::lists")) == false ||
+	  Fetcher.Clean(_config->FindDir("Dir::State::lists") + "partial/") == false)
+	 // something went wrong with the clean
+	 return false;
+   }
+
+   bool Res = true;
+
+   if (errorsWereReported == true)
+      Res = false;
+   else if (TransientNetworkFailure == true)
+      Res = _error->Warning(_("Some index files failed to download. They have been ignored, or old ones used instead."));
+   else if (Failed == true)
+      Res = _error->Error(_("Some index files failed to download. They have been ignored, or old ones used instead."));
+
+   // Run the success scripts if all was fine
+   if (RunUpdateScripts == true)
+   {
+      if(AllFailed == false)
+	 RunScripts("APT::Update::Post-Invoke-Success");
+
+      // Run the other scripts
+      RunScripts("APT::Update::Post-Invoke");
+   }
+   return Res;
+}
+									/*}}}*/
diff --git a/apt-pkg/update.h b/apt-pkg/update.h
new file mode 100644
index 0000000..dce5cbc
--- /dev/null
+++ b/apt-pkg/update.h
@@ -0,0 +1,22 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Update - ListUpdate related code
+
+   ##################################################################### */
+									/*}}}*/
+
+#ifndef PKGLIB_UPDATE_H
+#define PKGLIB_UPDATE_H
+
+class pkgAcquireStatus;
+class pkgSourceList;
+class pkgAcquire;
+
+APT_PUBLIC bool ListUpdate(pkgAcquireStatus &progress, pkgSourceList &List, int PulseInterval=0);
+APT_PUBLIC bool AcquireUpdate(pkgAcquire &Fetcher, int const PulseInterval = 0,
+		   bool const RunUpdateScripts = true, bool const ListCleanup = true);
+
+
+#endif
diff --git a/apt-pkg/upgrade.cc b/apt-pkg/upgrade.cc
new file mode 100644
index 0000000..e3e98e5
--- /dev/null
+++ b/apt-pkg/upgrade.cc
@@ -0,0 +1,393 @@
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/algorithms.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/depcache.h>
+#include <apt-pkg/edsp.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/progress.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/upgrade.h>
+
+#include <random>
+#include <string>
+
+#include <apti18n.h>
+									/*}}}*/
+
+struct PhasedUpgrader
+{
+   std::string machineID;
+   bool isChroot;
+
+   PhasedUpgrader()
+   {
+      machineID = APT::Configuration::getMachineID();
+   }
+
+   // See if this version is a security update. This also checks, for installed packages,
+   // if any of the previous versions is a security update
+   bool IsSecurityUpdate(pkgCache::VerIterator const &Ver)
+   {
+      auto Pkg = Ver.ParentPkg();
+      auto Installed = Pkg.CurrentVer();
+
+      auto OtherVer = Pkg.VersionList();
+
+      // Advance to first version < our version
+      while (OtherVer->ID != Ver->ID)
+	 ++OtherVer;
+      ++OtherVer;
+
+      // Iterate over all versions < our version
+      for (; !OtherVer.end() && (Installed.end() || OtherVer->ID != Installed->ID); OtherVer++)
+      {
+	 for (auto PF = OtherVer.FileList(); !PF.end(); PF++)
+	    if (PF.File() && PF.File().Archive() != nullptr && APT::String::Endswith(PF.File().Archive(), "-security"))
+	       return true;
+      }
+      return false;
+   }
+
+   // Check if this version is a phased update that should be ignored
+   bool IsIgnoredPhasedUpdate(pkgCache::VerIterator const &Ver)
+   {
+      if (_config->FindB("APT::Get::Phase-Policy", false))
+	 return false;
+
+      // The order and fallbacks for the always/never checks come from update-manager and exist
+      // to preserve compatibility.
+      if (_config->FindB("APT::Get::Always-Include-Phased-Updates",
+			 _config->FindB("Update-Manager::Always-Include-Phased-Updates", false)))
+	 return false;
+
+      if (_config->FindB("APT::Get::Never-Include-Phased-Updates",
+			 _config->FindB("Update-Manager::Never-Include-Phased-Updates", false)))
+	 return true;
+
+      if (machineID.empty()			    // no machine-id
+	  || getenv("SOURCE_DATE_EPOCH") != nullptr // reproducible build - always include
+	  || APT::Configuration::isChroot())
+	 return false;
+
+      std::string seedStr = std::string(Ver.SourcePkgName()) + "-" + Ver.SourceVerStr() + "-" + machineID;
+      std::seed_seq seed(seedStr.begin(), seedStr.end());
+      std::minstd_rand rand(seed);
+      std::uniform_int_distribution<unsigned int> dist(0, 100);
+
+      return dist(rand) > Ver.PhasedUpdatePercentage();
+   }
+
+   bool ShouldKeep(pkgDepCache &Cache, pkgCache::PkgIterator Pkg)
+   {
+      if (Pkg->CurrentVer == 0)
+	 return false;
+      if (Cache[Pkg].InstallVer == 0)
+	 return false;
+      if (Cache[Pkg].InstVerIter(Cache).PhasedUpdatePercentage() == 100)
+	 return false;
+      if (IsSecurityUpdate(Cache[Pkg].InstVerIter(Cache)))
+	 return false;
+      if (!IsIgnoredPhasedUpdate(Cache[Pkg].InstVerIter(Cache)))
+	 return false;
+
+      return true;
+   }
+
+   // Hold back upgrades to phased versions of already installed packages, unless
+   // they are security updates
+   void HoldBackIgnoredPhasedUpdates(pkgDepCache &Cache, pkgProblemResolver *Fix)
+   {
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      {
+	 if (not ShouldKeep(Cache, I))
+	    continue;
+
+	 Cache.MarkKeep(I, false, false);
+	 Cache.MarkProtected(I);
+	 if (Fix != nullptr)
+	    Fix->Protect(I);
+      }
+   }
+};
+
+// DistUpgrade - Distribution upgrade					/*{{{*/
+// ---------------------------------------------------------------------
+/* This autoinstalls every package and then force installs every 
+   pre-existing package. This creates the initial set of conditions which 
+   most likely contain problems because too many things were installed.
+   
+   The problem resolver is used to resolve the problems.
+ */
+static bool pkgDistUpgrade(pkgDepCache &Cache, OpProgress * const Progress)
+{
+   std::string const solver = _config->Find("APT::Solver", "internal");
+   auto const ret = EDSP::ResolveExternal(solver.c_str(), Cache, EDSP::Request::UPGRADE_ALL, Progress);
+   if (solver != "internal")
+      return ret;
+
+   if (Progress != NULL)
+      Progress->OverallProgress(0, 100, 1, _("Calculating upgrade"));
+
+   pkgDepCache::ActionGroup group(Cache);
+
+   PhasedUpgrader().HoldBackIgnoredPhasedUpdates(Cache, nullptr);
+
+   /* Upgrade all installed packages first without autoinst to help the resolver
+      in versioned or-groups to upgrade the old solver instead of installing
+      a new one (if the old solver is not the first one [anymore]) */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (I->CurrentVer != 0)
+	 Cache.MarkInstall(I, false, 0, false);
+
+   if (Progress != NULL)
+      Progress->Progress(10);
+
+   /* Auto upgrade all installed packages, this provides the basis 
+      for the installation */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (I->CurrentVer != 0)
+	 Cache.MarkInstall(I, true, 0, false);
+
+   if (Progress != NULL)
+      Progress->Progress(50);
+
+   /* Now, install each essential package which is not installed
+      (and not provided by another package in the same name group) */
+   std::string essential = _config->Find("pkgCacheGen::Essential", "all");
+   if (essential == "all")
+   {
+      for (pkgCache::GrpIterator G = Cache.GrpBegin(); G.end() == false; ++G)
+      {
+	 bool isEssential = false;
+	 bool instEssential = false;
+	 for (pkgCache::PkgIterator P = G.PackageList(); P.end() == false; P = G.NextPkg(P))
+	 {
+	    if ((P->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential)
+	       continue;
+	    isEssential = true;
+	    if (Cache[P].Install() == true)
+	    {
+	       instEssential = true;
+	       break;
+	    }
+	 }
+	 if (isEssential == false || instEssential == true)
+	    continue;
+	 pkgCache::PkgIterator P = G.FindPreferredPkg();
+	 Cache.MarkInstall(P, true, 0, false);
+      }
+   }
+   else if (essential != "none")
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+	 if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
+	    Cache.MarkInstall(I, true, 0, false);
+
+   if (Progress != NULL)
+      Progress->Progress(55);
+
+   /* We do it again over all previously installed packages to force 
+      conflict resolution on them all. */
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (I->CurrentVer != 0)
+	 Cache.MarkInstall(I, false, 0, false);
+
+   if (Progress != NULL)
+      Progress->Progress(65);
+
+   pkgProblemResolver Fix(&Cache);
+
+   if (Progress != NULL)
+      Progress->Progress(95);
+
+   // Hold back held packages.
+   if (_config->FindB("APT::Ignore-Hold",false) == false)
+   {
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      {
+	 if (I->SelectedState == pkgCache::State::Hold)
+	 {
+	    Fix.Protect(I);
+	    Cache.MarkKeep(I, false, false);
+	 }
+      }
+   }
+
+   PhasedUpgrader().HoldBackIgnoredPhasedUpdates(Cache, &Fix);
+
+   bool const success = Fix.ResolveInternal(false);
+   if (Progress != NULL)
+      Progress->Done();
+   return success;
+}									/*}}}*/
+// AllUpgradeNoNewPackages - Upgrade but no removals or new pkgs        /*{{{*/
+static bool pkgAllUpgradeNoNewPackages(pkgDepCache &Cache, OpProgress * const Progress)
+{
+   std::string const solver = _config->Find("APT::Solver", "internal");
+   constexpr auto flags = EDSP::Request::UPGRADE_ALL | EDSP::Request::FORBID_NEW_INSTALL | EDSP::Request::FORBID_REMOVE;
+   auto const ret = EDSP::ResolveExternal(solver.c_str(), Cache, flags, Progress);
+   if (solver != "internal")
+      return ret;
+
+   if (Progress != NULL)
+      Progress->OverallProgress(0, 100, 1, _("Calculating upgrade"));
+
+   pkgDepCache::ActionGroup group(Cache);
+   pkgProblemResolver Fix(&Cache);
+   PhasedUpgrader phasedUpgrader;
+   // Upgrade all installed packages
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (Cache[I].Install() == true)
+	 Fix.Protect(I);
+	  
+      if (_config->FindB("APT::Ignore-Hold",false) == false)
+	 if (I->SelectedState == pkgCache::State::Hold)
+	    continue;
+
+      if (phasedUpgrader.ShouldKeep(Cache, I))
+	 continue;
+
+      if (I->CurrentVer != 0 && Cache[I].InstallVer != 0)
+	 Cache.MarkInstall(I, false, 0, false);
+   }
+
+   if (Progress != NULL)
+      Progress->Progress(50);
+
+   phasedUpgrader.HoldBackIgnoredPhasedUpdates(Cache, &Fix);
+
+   // resolve remaining issues via keep
+   bool const success = Fix.ResolveByKeepInternal();
+   if (Progress != NULL)
+      Progress->Done();
+   return success;
+}
+									/*}}}*/
+// AllUpgradeWithNewInstalls - Upgrade + install new packages as needed /*{{{*/
+// ---------------------------------------------------------------------
+/* Right now the system must be consistent before this can be called.
+ * Upgrade as much as possible without deleting anything (useful for
+ * stable systems)
+ */
+static bool pkgAllUpgradeWithNewPackages(pkgDepCache &Cache, OpProgress * const Progress)
+{
+   std::string const solver = _config->Find("APT::Solver", "internal");
+   constexpr auto flags = EDSP::Request::UPGRADE_ALL | EDSP::Request::FORBID_REMOVE;
+   auto const ret = EDSP::ResolveExternal(solver.c_str(), Cache, flags, Progress);
+   if (solver != "internal")
+      return ret;
+
+   if (Progress != NULL)
+      Progress->OverallProgress(0, 100, 1, _("Calculating upgrade"));
+
+   pkgDepCache::ActionGroup group(Cache);
+   pkgProblemResolver Fix(&Cache);
+   PhasedUpgrader phasedUpgrader;
+
+   // provide the initial set of stuff we want to upgrade by marking
+   // all upgradable packages for upgrade
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+   {
+      if (I->CurrentVer != 0 && Cache[I].InstallVer != 0)
+      {
+         if (_config->FindB("APT::Ignore-Hold",false) == false)
+            if (I->SelectedState == pkgCache::State::Hold)
+               continue;
+	 if (phasedUpgrader.ShouldKeep(Cache, I))
+	    continue;
+
+	 Cache.MarkInstall(I, false, 0, false);
+      }
+   }
+
+   if (Progress != NULL)
+      Progress->Progress(10);
+
+   // then let auto-install loose
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (Cache[I].Install())
+	 Cache.MarkInstall(I, true, 0, false);
+
+   if (Progress != NULL)
+      Progress->Progress(50);
+
+   // ... but it may remove stuff, we need to clean up afterwards again
+   for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      if (Cache[I].Delete() == true)
+	 Cache.MarkKeep(I, false, false);
+
+   if (Progress != NULL)
+      Progress->Progress(60);
+
+   phasedUpgrader.HoldBackIgnoredPhasedUpdates(Cache, &Fix);
+
+   // resolve remaining issues via keep
+   bool const success = Fix.ResolveByKeepInternal();
+   if (Progress != NULL)
+      Progress->Done();
+   return success;
+}
+									/*}}}*/
+// MinimizeUpgrade - Minimizes the set of packages to be upgraded	/*{{{*/
+// ---------------------------------------------------------------------
+/* This simply goes over the entire set of packages and tries to keep 
+   each package marked for upgrade. If a conflict is generated then 
+   the package is restored. */
+bool pkgMinimizeUpgrade(pkgDepCache &Cache)
+{   
+   pkgDepCache::ActionGroup group(Cache);
+
+   if (Cache.BrokenCount() != 0)
+      return false;
+   
+   // We loop for 10 tries to get the minimal set size.
+   bool Change = false;
+   unsigned int Count = 0;
+   do
+   {
+      Change = false;
+      for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
+      {
+	 // Not interesting
+	 if (Cache[I].Upgrade() == false || Cache[I].NewInstall() == true)
+	    continue;
+
+	 // Keep it and see if that is OK
+	 Cache.MarkKeep(I, false, false);
+	 if (Cache.BrokenCount() != 0)
+	    Cache.MarkInstall(I, false, 0, false);
+	 else
+	 {
+	    // If keep didn't actually do anything then there was no change..
+	    if (Cache[I].Upgrade() == false)
+	       Change = true;
+	 }	 
+      }      
+      ++Count;
+   }
+   while (Change == true && Count < 10);
+
+   if (Cache.BrokenCount() != 0)
+      return _error->Error("Internal Error in pkgMinimizeUpgrade");
+   
+   return true;
+}
+									/*}}}*/
+// APT::Upgrade::Upgrade - Upgrade using a specific strategy		/*{{{*/
+bool APT::Upgrade::Upgrade(pkgDepCache &Cache, int mode, OpProgress * const Progress)
+{
+   if (mode == ALLOW_EVERYTHING)
+      return pkgDistUpgrade(Cache, Progress);
+   else if ((mode & ~FORBID_REMOVE_PACKAGES) == 0)
+      return pkgAllUpgradeWithNewPackages(Cache, Progress);
+   else if ((mode & ~(FORBID_REMOVE_PACKAGES|FORBID_INSTALL_NEW_PACKAGES)) == 0)
+      return pkgAllUpgradeNoNewPackages(Cache, Progress);
+   else
+      _error->Error("pkgAllUpgrade called with unsupported mode %i", mode);
+   return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/upgrade.h b/apt-pkg/upgrade.h
new file mode 100644
index 0000000..8e89601
--- /dev/null
+++ b/apt-pkg/upgrade.h
@@ -0,0 +1,32 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Upgrade - Upgrade/DistUpgrade related code
+
+   ##################################################################### */
+									/*}}}*/
+
+#ifndef PKGLIB_UPGRADE_H
+#define PKGLIB_UPGRADE_H
+
+#include <apt-pkg/macros.h>
+#include <stddef.h>
+
+class pkgDepCache;
+class OpProgress;
+
+namespace APT {
+   namespace Upgrade {
+      // FIXME: make this "enum class UpgradeMode {" once we enable c++11
+      enum UpgradeMode {
+         FORBID_REMOVE_PACKAGES = 1,
+         FORBID_INSTALL_NEW_PACKAGES = 2,
+	 ALLOW_EVERYTHING = 0
+      };
+      APT_PUBLIC bool Upgrade(pkgDepCache &Cache, int UpgradeMode, OpProgress * const Progress = NULL);
+   }
+}
+
+APT_PUBLIC bool pkgMinimizeUpgrade(pkgDepCache &Cache);
+#endif
diff --git a/apt-pkg/version.cc b/apt-pkg/version.cc
new file mode 100644
index 0000000..e0b83e0
--- /dev/null
+++ b/apt-pkg/version.cc
@@ -0,0 +1,44 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Version - Versioning system..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/version.h>
+
+#include <stdlib.h>
+#include <string.h>
+									/*}}}*/
+    
+static pkgVersioningSystem *VSList[10];
+pkgVersioningSystem **pkgVersioningSystem::GlobalList = VSList;
+unsigned long pkgVersioningSystem::GlobalListLen = 0;
+
+// pkgVS::pkgVersioningSystem - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* Link to the global list of versioning systems supported */
+pkgVersioningSystem::pkgVersioningSystem() : Label(NULL)
+{
+   VSList[GlobalListLen] = this;
+   ++GlobalListLen;
+}
+									/*}}}*/
+// pkgVS::GetVS - Find a VS by name					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgVersioningSystem *pkgVersioningSystem::GetVS(const char *Label)
+{
+   for (unsigned I = 0; I != GlobalListLen; I++)
+      if (strcmp(VSList[I]->Label,Label) == 0)
+	 return VSList[I];
+   return 0;
+}
+									/*}}}*/
+
+
+pkgVersioningSystem::~pkgVersioningSystem() {}
diff --git a/apt-pkg/version.h b/apt-pkg/version.h
new file mode 100644
index 0000000..eaf667c
--- /dev/null
+++ b/apt-pkg/version.h
@@ -0,0 +1,57 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Version - Versioning system..
+
+   The versioning system represents how versions are compared, represented
+   and how dependencies are evaluated. As a general rule versioning
+   systems are not compatible unless specifically allowed by the 
+   TestCompatibility query.
+   
+   The versions are stored in a global list of versions, but that is just
+   so that they can be queried when someone does 'apt-get -v'. 
+   pkgSystem provides the proper means to access the VS for the active
+   system.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_VERSION_H
+#define PKGLIB_VERSION_H
+
+#include <apt-pkg/strutl.h>
+#include <string>
+
+
+class APT_PUBLIC pkgVersioningSystem
+{
+   public:
+   // Global list of VS's
+   static pkgVersioningSystem **GlobalList;
+   static unsigned long GlobalListLen;
+   static pkgVersioningSystem *GetVS(const char *Label) APT_PURE;
+   
+   const char *Label;
+   
+   // Compare versions..
+   virtual int DoCmpVersion(const char *A,const char *Aend,
+			  const char *B,const char *Bend) = 0;   
+
+   virtual bool CheckDep(const char *PkgVer,int Op,const char *DepVer) = 0;
+   virtual int DoCmpReleaseVer(const char *A,const char *Aend,
+			       const char *B,const char *Bend) = 0;
+   virtual std::string UpstreamVersion(const char *A) = 0;
+   
+   // See if the given VS is compatible with this one.. 
+   virtual bool TestCompatibility(pkgVersioningSystem const &Against) 
+                {return this == &Against;};
+
+   // Shortcuts
+   APT_MKSTRCMP(CmpVersion,DoCmpVersion);
+   APT_MKSTRCMP(CmpReleaseVer,DoCmpReleaseVer);
+   
+   pkgVersioningSystem();
+   virtual ~pkgVersioningSystem();
+};
+
+#endif
diff --git a/apt-pkg/versionmatch.cc b/apt-pkg/versionmatch.cc
new file mode 100644
index 0000000..83a969c
--- /dev/null
+++ b/apt-pkg/versionmatch.cc
@@ -0,0 +1,307 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Version Matching 
+   
+   This module takes a matching string and a type and locates the version
+   record that satisfies the constraint described by the matching string.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/versionmatch.h>
+
+#include <string>
+#include <ctype.h>
+#include <fnmatch.h>
+#include <regex.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+									/*}}}*/
+
+using std::string;
+
+// VersionMatch::pkgVersionMatch - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* Break up the data string according to the selected type */
+pkgVersionMatch::pkgVersionMatch(string Data,MatchType Type) : Type(Type)
+{
+   MatchAll = false;
+   VerPrefixMatch = false;
+   RelVerPrefixMatch = false;
+   
+   if (Type == None || Data.length() < 1)
+      return;
+   
+   // Cut up the version representation
+   if (Type == Version)
+   {
+      if (Data.end()[-1] == '*')
+      {
+	 VerPrefixMatch = true;
+	 VerStr = string(Data,0,Data.length()-1);
+      }
+      else
+	 VerStr = Data;
+      return;
+   }   
+   
+   if (Type == Release)
+   {
+      // All empty = match all
+      if (Data == "*")
+      {
+	 MatchAll = true;
+	 return;
+      }
+      
+      // Are we a simple specification?
+      string::const_iterator I = Data.begin();
+      for (; I != Data.end() && *I != '='; ++I);
+      if (I == Data.end())
+      {
+	 // Temporary
+	 if (isdigit(Data[0]))
+	    RelVerStr = Data;
+	 else
+	    RelRelease = Data;
+
+	 if (RelVerStr.length() > 0 && RelVerStr.end()[-1] == '*')
+	 {
+	    RelVerPrefixMatch = true;
+	    RelVerStr = string(RelVerStr.begin(),RelVerStr.end()-1);
+	 }	 
+	 return;
+      }
+            
+      char Spec[300];
+      char *Fragments[20];
+      snprintf(Spec,sizeof(Spec),"%s",Data.c_str());
+      if (TokSplitString(',',Spec,Fragments,
+			 sizeof(Fragments)/sizeof(Fragments[0])) == false)
+      {
+	 Type = None;
+	 return;
+      }
+      
+      for (unsigned J = 0; Fragments[J] != 0; J++)
+      {
+	 if (strlen(Fragments[J]) < 3)
+	    continue;
+
+	 if (stringcasecmp(Fragments[J],Fragments[J]+2,"v=") == 0)
+	    RelVerStr = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"o=") == 0)
+	    RelOrigin = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"a=") == 0)
+	    RelArchive = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"n=") == 0)
+	    RelCodename = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"l=") == 0)
+	    RelLabel = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"c=") == 0)
+	    RelComponent = Fragments[J]+2;
+	 else if (stringcasecmp(Fragments[J],Fragments[J]+2,"b=") == 0)
+	    RelArchitecture = Fragments[J]+2;
+      }
+
+      if (RelVerStr.end()[-1] == '*')
+      {
+	 RelVerPrefixMatch = true;
+	 RelVerStr = string(RelVerStr.begin(),RelVerStr.end()-1);
+      }	 
+      return;
+   }
+   
+   if (Type == Origin)
+   {
+      if (Data[0] == '"' && Data.length() >= 2 && Data.end()[-1] == '"')
+	 OrSite = Data.substr(1, Data.length() - 2);
+      else
+	 OrSite = Data;
+      return;
+   }   
+}
+									/*}}}*/
+// VersionMatch::MatchVer - Match a version string with prefixing	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgVersionMatch::MatchVer(const char *A,string B,bool Prefix)
+{
+   if (A == NULL)
+      return false;
+
+   const char *Ab = A;
+   const char *Ae = Ab + strlen(A);
+   
+   // Strings are not a compatible size.
+   if (((unsigned)(Ae - Ab) != B.length() && Prefix == false) ||
+       (unsigned)(Ae - Ab) < B.length())
+      return false;
+   
+   // Match (leading?)
+   if (stringcasecmp(B,Ab,Ab + B.length()) == 0)
+      return true;
+   
+   return false;
+}
+									/*}}}*/
+// VersionMatch::Find - Locate the best match for the select type	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+pkgCache::VerIterator pkgVersionMatch::Find(pkgCache::PkgIterator Pkg)
+{
+   for (auto Ver = Pkg.VersionList(); not Ver.end(); ++Ver)
+      if (VersionMatches(Ver))
+	 return Ver;
+   // check if the package provides itself in a matching version
+   for (auto Prov = Pkg.ProvidesList(); not Prov.end(); ++Prov)
+      if (Prov->ProvideVersion != 0 && Prov.OwnerPkg() == Prov.ParentPkg())
+	 if (MatchVer(Prov.ProvideVersion(), VerStr, VerPrefixMatch) ||
+	     ExpressionMatches(VerStr, Prov.ProvideVersion()))
+	    return Prov.OwnerVer();
+   return pkgCache::VerIterator{};
+}
+									/*}}}*/
+
+// VersionMatch::Find - Locate the best match for the select type	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgVersionMatch::VersionMatches(pkgCache::VerIterator Ver)
+{
+   if (Type == Version)
+   {
+      if (MatchVer(Ver.VerStr(),VerStr,VerPrefixMatch) == true)
+	 return true;
+      if (ExpressionMatches(VerStr, Ver.VerStr()) == true)
+	 return true;
+      return false;
+   }
+
+   for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
+      if (FileMatch(VF.File()) == true)
+	 return true;
+
+   return false;
+}
+									/*}}}*/
+
+#ifndef FNM_CASEFOLD
+#define FNM_CASEFOLD 0
+#endif
+
+bool pkgVersionMatch::ExpressionMatches(const char *pattern, const char *string)/*{{{*/
+{
+   if (pattern == NULL || string == NULL)
+      return false;
+   if (pattern[0] == '/') {
+      size_t length = strlen(pattern);
+      if (pattern[length - 1] == '/') {
+	 bool res = false;
+	 regex_t preg;
+	 char *regex = strdup(pattern + 1);
+	 regex[length - 2] = '\0';
+	 if (regcomp(&preg, regex, REG_EXTENDED | REG_ICASE) != 0) {
+	    _error->Warning("Invalid regular expression: %s", regex);
+	 } else if (regexec(&preg, string, 0, NULL, 0) == 0) {
+	    res = true;
+	 }
+	 free(regex);
+	 regfree(&preg);
+	 return res;
+      }
+   }
+   return fnmatch(pattern, string, FNM_CASEFOLD) == 0;
+}
+bool pkgVersionMatch::ExpressionMatches(const std::string& pattern, const char *string)
+{
+    return ExpressionMatches(pattern.c_str(), string);
+}
+									/*}}}*/
+// VersionMatch::FileMatch - Match against an index file		/*{{{*/
+// ---------------------------------------------------------------------
+/* This matcher checks against the release file and the origin location
+   to see if the constraints are met. */
+bool pkgVersionMatch::FileMatch(pkgCache::RlsFileIterator const &File)
+{
+   if (Type == Release)
+   {
+      if (MatchAll)
+	 return true;
+
+      if (RelVerStr.empty() && RelOrigin.empty() &&
+	  RelArchive.empty() && RelLabel.empty() &&
+	  RelRelease.empty() && RelCodename.empty() &&
+	  RelComponent.empty() && RelArchitecture.empty())
+	 return false;
+
+      if (not RelVerStr.empty() && not MatchVer(File.Version(), RelVerStr, RelVerPrefixMatch) &&
+	  not ExpressionMatches(RelVerStr, File.Version()))
+	 return false;
+      if (not RelOrigin.empty() && not ExpressionMatches(RelOrigin, File.Origin()))
+	 return false;
+      if (not RelArchive.empty() && not ExpressionMatches(RelArchive, File.Archive()))
+	 return false;
+      if (not RelCodename.empty() && not ExpressionMatches(RelCodename, File.Codename()))
+	 return false;
+      if (not RelRelease.empty() && not ExpressionMatches(RelRelease, File.Archive()) &&
+	  not ExpressionMatches(RelRelease, File.Codename()))
+	 return false;
+      if (not RelLabel.empty() && not ExpressionMatches(RelLabel, File.Label()))
+	 return false;
+      return true;
+   }
+
+   if (Type == Origin)
+   {
+      if (not OrSite.empty() && File.Site() == nullptr)
+	 return false;
+      return ExpressionMatches(OrSite, File.Site()); /* both strings match */
+   }
+
+   return false;
+}
+bool pkgVersionMatch::FileMatch(pkgCache::PkgFileIterator File)
+{
+   if (auto const RlsFile = File.ReleaseFile(); not RlsFile.end())
+   {
+      if (not FileMatch(RlsFile))
+	 return false;
+   }
+   else if (Type == Release)
+   {
+      // only 'bad' files like dpkg.status file have no release file
+      // those reuse the Component of te PkgFile to store the Archive "now".
+      if (not RelArchive.empty() && not ExpressionMatches(RelArchive, File.Component()))
+	 return false;
+      if (not RelRelease.empty() && not ExpressionMatches(RelRelease, File.Component()))
+	 return false;
+      if (not RelOrigin.empty() || not RelLabel.empty() ||
+	  not RelVerStr.empty() || not RelCodename.empty())
+	 return false;
+   }
+   else
+      return false;
+
+   if (Type == Release)
+   {
+      if (MatchAll)
+	 return true;
+
+      if (not RelComponent.empty() && not ExpressionMatches(RelComponent, File.Component()))
+	 return false;
+      if (not RelArchitecture.empty() && not ExpressionMatches(RelArchitecture, File.Architecture()))
+	 return false;
+   }
+
+   return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/versionmatch.h b/apt-pkg/versionmatch.h
new file mode 100644
index 0000000..faf1fd4
--- /dev/null
+++ b/apt-pkg/versionmatch.h
@@ -0,0 +1,78 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Version Matching
+
+   This module takes a matching string and a type and locates the version
+   record that satisfies the constraint described by the matching string.
+
+     Version: 1.2*
+     Release: o=Debian,v=2.1*,c=main
+     Release: v=2.1*
+     Release: a=testing
+     Release: n=squeeze
+     Release: *
+     Origin: ftp.debian.org
+
+   Release may be a complex type that can specify matches for any of:
+      Version (v= with prefix)
+      Origin (o=)
+      Archive (a=) eg, unstable, testing, stable
+      Codename (n=) e.g. etch, lenny, squeeze, sid
+      Label (l=)
+      Component (c=)
+      Binary Architecture (b=)
+   If there are no equals signs in the string then it is scanned in short
+   form - if it starts with a number it is Version otherwise it is an
+   Archive or a Codename.
+
+   Release may be a '*' to match all releases.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_VERSIONMATCH_H
+#define PKGLIB_VERSIONMATCH_H
+
+#include <apt-pkg/pkgcache.h>
+
+#include <string>
+
+
+class APT_PUBLIC pkgVersionMatch
+{
+   // Version Matching
+   std::string VerStr;
+   bool VerPrefixMatch;
+
+   // Release Matching
+   std::string RelVerStr;
+   bool RelVerPrefixMatch;
+   std::string RelOrigin;
+   std::string RelRelease;
+   std::string RelCodename;
+   std::string RelArchive;
+   std::string RelLabel;
+   std::string RelComponent;
+   std::string RelArchitecture;
+   bool MatchAll;
+
+   // Origin Matching
+   std::string OrSite;
+
+   public:
+
+   enum MatchType {None = 0,Version,Release,Origin} Type;
+
+   bool MatchVer(const char *A,std::string B,bool Prefix) APT_PURE;
+   static bool ExpressionMatches(const char *pattern, const char *string);
+   static bool ExpressionMatches(const std::string& pattern, const char *string);
+   bool FileMatch(pkgCache::PkgFileIterator File);
+   bool FileMatch(pkgCache::RlsFileIterator const &File);
+   pkgCache::VerIterator Find(pkgCache::PkgIterator Pkg);
+   bool VersionMatches(pkgCache::VerIterator Ver);
+
+   pkgVersionMatch(std::string Data,MatchType Type);
+};
+
+#endif