Adding upstream version 2.2.4.upstream/2.2.4upstream

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

1 files changed, 4057 insertions, 0 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
new file mode 100644
index 0000000..73d2b0c
--- /dev/null
+++ b/apt-pkg/acquire-item.cc
@@ -0,0 +1,4057 @@
+// -*- 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;
+
+   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", 0)), 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 decompresion 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() : "";
+}
+									/*}}}*/
+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: " + 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);
+	 TransactionManager->TransactionStageCopy(this, PartialRelease, FinalRelease);
+	 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->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: " + 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->QueueIndexes(GoodLoad);
+
+      TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, FinalRelease);
+   }
+   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");
+      std::string const tmp = Tags.FindS(tagname.c_str());
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash;
+      unsigned long long size;
+      std::stringstream ss(tmp);
+      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");
+      std::string const tmp = Tags.FindS(tagname.c_str());
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp);
+      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");
+      std::string const tmp = Tags.FindS(tagname.c_str());
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp);
+      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");
+      std::string const tmp = Tags.FindS(tagname.c_str());
+      if (tmp.empty() == true)
+	 continue;
+
+      string hash, filename;
+      unsigned long long size;
+      std::stringstream ss(tmp);
+      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
+      std::string const precedence = Tags.FindS("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)
+      {
+	 Init(TargetURI, Desc.Description, Desc.ShortDesc);
+	 Status = StatIdle;
+	 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-modfied-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 supposely 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->Warning("Repository is broken: %s (= %s) has no Size information",
+		      Version.ParentPkg().FullName(false).c_str(),
+		      Version.VerStr());
+   }
+
+   // 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)
+      {
+	 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";
+	 if (FileExists(debianname))
+	    return "copy://" + debianname;
+	 else if (FileExists(debianname + ".gz"))
+	    return "store://" + debianname + ".gz";
+	 else if (FileExists(basename))
+	    return "copy://" + basename;
+	 else if (FileExists(basename + ".gz"))
+	    return "store://" + basename + ".gz";
+      }
+   }
+
+   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() {}