Adding upstream version 2.6.1.upstream/2.6.1upstream

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

34 files changed, 12603 insertions, 0 deletions

diff --git a/apt-pkg/contrib/arfile.cc b/apt-pkg/contrib/arfile.cc
new file mode 100644
index 0000000..6d4a1f1
--- /dev/null
+++ b/apt-pkg/contrib/arfile.cc
@@ -0,0 +1,179 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   AR File - Handle an 'AR' archive
+   
+   AR Archives have plain text headers at the start of each file
+   section. The headers are aligned on a 2 byte boundary.
+   
+   Information about the structure of AR files can be found in ar(5)
+   on a BSD system, or in the binutils source.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/arfile.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <string>
+#include <string.h>
+#include <sys/types.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+struct ARArchive::MemberHeader
+{
+   char Name[16];
+   char MTime[12];
+   char UID[6];
+   char GID[6];
+   char Mode[8];
+   char Size[10];
+   char Magic[2];
+};
+
+// ARArchive::ARArchive - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ARArchive::ARArchive(FileFd &File) : List(0), File(File)
+{
+   LoadHeaders();
+}
+									/*}}}*/
+// ARArchive::~ARArchive - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ARArchive::~ARArchive()
+{
+   while (List != 0)
+   {
+      Member *Tmp = List;
+      List = List->Next;
+      delete Tmp;
+   }   
+}
+									/*}}}*/
+// ARArchive::LoadHeaders - Load the headers from each file		/*{{{*/
+// ---------------------------------------------------------------------
+/* AR files are structured with a 8 byte magic string followed by a 60
+   byte plain text header then the file data, another header, data, etc */
+bool ARArchive::LoadHeaders()
+{
+   off_t Left = File.Size();
+   
+   // Check the magic byte
+   char Magic[8];
+   if (File.Read(Magic,sizeof(Magic)) == false)
+      return false;
+   if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
+      return _error->Error(_("Invalid archive signature"));
+   Left -= sizeof(Magic);
+   
+   // Read the member list
+   while (Left > 0)
+   {
+      MemberHeader Head;
+      if (File.Read(&Head,sizeof(Head)) == false)
+	 return _error->Error(_("Error reading archive member header"));
+      Left -= sizeof(Head);
+
+      // Convert all of the integer members
+      Member *Memb = new Member();
+      if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
+	  StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
+	  StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
+	  StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
+	  StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
+      {
+	 delete Memb;
+	 return _error->Error(_("Invalid archive member header"));
+      }
+
+      if (Left < 0 || Memb->Size > static_cast<unsigned long long>(Left))
+      {
+	 delete Memb;
+	 return _error->Error(_("Invalid archive member header"));
+      }
+      // Check for an extra long name string
+      if (memcmp(Head.Name,"#1/",3) == 0)
+      {
+	 char S[300];
+	 unsigned long Len;
+	 if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
+	     Len >= sizeof(S))
+	 {
+	    delete Memb;
+	    return _error->Error(_("Invalid archive member header"));
+	 }
+
+	 if (Len > Memb->Size)
+	 {
+	    delete Memb;
+	    return _error->Error(_("Invalid archive member header"));
+	 }
+
+	 if (File.Read(S,Len) == false)
+	 {
+	    delete Memb;
+	    return false;
+	 }
+	 S[Len] = 0;
+	 Memb->Name = S;
+	 Memb->Size -= Len;
+	 Left -= Len;
+      }
+      else
+      {
+	 unsigned int I = sizeof(Head.Name) - 1;
+	 for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--)
+	 {
+	    if (I == 0)
+	    {
+	       delete Memb;
+	       return _error->Error(_("Invalid archive member header"));
+	    }
+	 }
+	 Memb->Name = std::string(Head.Name,I+1);
+      }
+
+      // Account for the AR header alignment 
+      off_t Skip = Memb->Size % 2;
+      
+      // Add it to the list
+      Memb->Next = List;
+      List = Memb;
+      Memb->Start = File.Tell();
+      if (File.Skip(Memb->Size + Skip) == false)
+	 return false;
+      if (Left < (off_t)(Memb->Size + Skip))
+	 return _error->Error(_("Archive is too short"));
+      Left -= Memb->Size + Skip;
+   }   
+   if (Left != 0)
+      return _error->Error(_("Failed to read the archive headers"));
+   
+   return true;
+}
+									/*}}}*/
+// ARArchive::FindMember - Find a name in the member list		/*{{{*/
+// ---------------------------------------------------------------------
+/* Find a member with the given name */
+const ARArchive::Member *ARArchive::FindMember(const char *Name) const
+{
+   const Member *Res = List;
+   while (Res != 0)
+   {
+      if (Res->Name == Name)
+	 return Res;
+      Res = Res->Next;
+   }
+   
+   return 0;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/arfile.h b/apt-pkg/contrib/arfile.h
new file mode 100644
index 0000000..9b13ed9
--- /dev/null
+++ b/apt-pkg/contrib/arfile.h
@@ -0,0 +1,66 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   AR File - Handle an 'AR' archive
+   
+   This is a reader for the usual 4.4 BSD AR format. It allows raw
+   stream access to a single member at a time. Basically all this class
+   provides is header parsing and verification. It is up to the client
+   to correctly make use of the stream start/stop points.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ARFILE_H
+#define PKGLIB_ARFILE_H
+
+#include <apt-pkg/macros.h>
+#include <string>
+
+class FileFd;
+
+class APT_PUBLIC ARArchive
+{
+   struct MemberHeader;
+   public:
+   struct Member;
+   
+   protected:
+
+   // Linked list of members
+   Member *List;
+   
+   bool LoadHeaders();
+
+   public:
+   
+   // The stream file
+   FileFd &File;
+
+   // Locate a member by name
+   const Member *FindMember(const char *Name) const;
+   inline Member *Members() { return List; }
+   
+   APT_PUBLIC explicit ARArchive(FileFd &File);
+   APT_PUBLIC ~ARArchive();
+};
+
+// A member of the archive
+struct ARArchive::Member
+{
+   // Fields from the header
+   std::string Name;
+   unsigned long MTime;
+   unsigned long UID;
+   unsigned long GID;
+   unsigned long Mode;
+   unsigned long long Size;
+   
+   // Location of the data.
+   unsigned long long Start;
+   Member *Next;
+   
+   Member() : Start(0), Next(0) {};
+};
+
+#endif
diff --git a/apt-pkg/contrib/cdromutl.cc b/apt-pkg/contrib/cdromutl.cc
new file mode 100644
index 0000000..f402017
--- /dev/null
+++ b/apt-pkg/contrib/cdromutl.cc
@@ -0,0 +1,293 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   CDROM Utilities - Some functions to manipulate CDROM mounts.
+   
+   These are here for the cdrom method and apt-cdrom.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cdromutl.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/strutl.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using std::string;
+
+// IsMounted - Returns true if the mount point is mounted		/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a simple algorithm that should always work, we stat the mount point
+   and the '..' file in the mount point and see if they are on the same device.
+   By definition if they are the same then it is not mounted. This should 
+   account for symlinked mount points as well. */
+bool IsMounted(string &Path)
+{
+   if (Path.empty() == true)
+      return false;
+
+   // Need that trailing slash for directories
+   if (Path[Path.length() - 1] != '/')
+      Path += '/';
+
+   // if the path has a ".disk" directory we treat it as mounted
+   // this way even extracted copies of disks are recognized
+   if (DirectoryExists(Path + ".disk/") == true)
+      return true;
+
+   /* First we check if the path is actually mounted, we do this by
+      stating the path and the previous directory (careful of links!)
+      and comparing their device fields. */
+   struct stat Buf,Buf2;
+   if (stat(Path.c_str(),&Buf) != 0 || 
+       stat((Path + "../").c_str(),&Buf2) != 0)
+      return _error->Errno("stat",_("Unable to stat the mount point %s"),Path.c_str());
+
+   if (Buf.st_dev == Buf2.st_dev)
+      return false;
+   return true;
+}
+									/*}}}*/
+// UnmountCdrom - Unmount a cdrom					/*{{{*/
+// ---------------------------------------------------------------------
+/* Forking umount works much better than the umount syscall which can 
+   leave /etc/mtab inconsistent. We drop all messages this produces. */
+bool UnmountCdrom(string Path)
+{
+   // do not generate errors, even if the mountpoint does not exist
+   // the mountpoint might be auto-created by the mount command
+   // and a non-existing mountpoint is surely not mounted
+   _error->PushToStack();
+   bool const mounted = IsMounted(Path);
+   _error->RevertToStack();
+   if (mounted == false)
+      return true;
+
+   for (int i=0;i<3;i++)
+   {
+   
+      int Child = ExecFork();
+
+      // The child
+      if (Child == 0)
+      {
+	 // Make all the fds /dev/null
+	 int const null_fd = open("/dev/null",O_RDWR);
+	 for (int I = 0; I != 3; ++I)
+	    dup2(null_fd, I);
+
+	 if (_config->Exists("Acquire::cdrom::"+Path+"::UMount") == true)
+	 {
+	    if (system(_config->Find("Acquire::cdrom::"+Path+"::UMount").c_str()) != 0)
+	       _exit(100);
+	    _exit(0);	 	 
+	 }
+	 else
+	 {
+	    const char * const Args[] = {
+	       "umount",
+	       Path.c_str(),
+	       nullptr
+	    };
+	    execvp(Args[0], const_cast<char **>(Args));
+	    _exit(100);
+	 }
+      }
+
+      // if it can not be umounted, give it a bit more time
+      // this can happen when auto-mount magic or fs/cdrom prober attack
+      if (ExecWait(Child,"umount",true) == true)
+	 return true;
+      sleep(1);
+   }
+
+   return false;
+}
+									/*}}}*/
+// MountCdrom - Mount a cdrom						/*{{{*/
+// ---------------------------------------------------------------------
+/* We fork mount and drop all messages */
+bool MountCdrom(string Path, string DeviceName)
+{
+   // do not generate errors, even if the mountpoint does not exist
+   // the mountpoint might be auto-created by the mount command
+   _error->PushToStack();
+   bool const mounted = IsMounted(Path);
+   _error->RevertToStack();
+   if (mounted == true)
+      return true;
+
+   int Child = ExecFork();
+
+   // The child
+   if (Child == 0)
+   {
+      // Make all the fds /dev/null
+      int const null_fd = open("/dev/null",O_RDWR);
+      for (int I = 0; I != 3; ++I)
+	 dup2(null_fd, I);
+
+      if (_config->Exists("Acquire::cdrom::"+Path+"::Mount") == true)
+      {
+	 if (system(_config->Find("Acquire::cdrom::"+Path+"::Mount").c_str()) != 0)
+	    _exit(100);
+	 _exit(0);	 
+      }
+      else
+      {
+	 const char *Args[10];
+	 Args[0] = "mount";
+	 if (DeviceName == "") 
+	 {
+	    Args[1] = Path.c_str();
+	    Args[2] = 0;
+	 } else {
+	    Args[1] = DeviceName.c_str();
+	    Args[2] = Path.c_str();
+	    Args[3] = 0;
+	 }
+	 execvp(Args[0],(char **)Args);      
+	 _exit(100);
+      }      
+   }
+
+   // Wait for mount
+   return ExecWait(Child,"mount",true);
+}
+									/*}}}*/
+// IdentCdrom - Generate a unique string for this CD			/*{{{*/
+// ---------------------------------------------------------------------
+/* We convert everything we hash into a string, this prevents byte size/order
+   from effecting the outcome. */
+bool IdentCdrom(string CD,string &Res,unsigned int Version)
+{
+   Hashes Hash(Hashes::MD5SUM);
+   bool writable_media = false;
+
+   int dirfd = open(CD.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+   if (dirfd == -1)
+      return _error->Errno("open",_("Unable to read %s"),CD.c_str());
+
+   // if we are on a writable medium (like a usb-stick) that is just
+   // used like a cdrom don't use "." as it will constantly change,
+   // use .disk instead
+   if (faccessat(dirfd, ".", W_OK, 0) == 0)
+   {
+      int diskfd = openat(dirfd, "./.disk", O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0);
+      if (diskfd != -1)
+      {
+	 close(dirfd);
+	 dirfd = diskfd;
+	 writable_media = true;
+	 CD = CD.append("/.disk");
+	 if (_config->FindB("Debug::aptcdrom",false) == true)
+	    std::clog << "Found writable cdrom, using alternative path: " << CD
+	       << std::endl;
+      }
+   }
+
+   DIR * const D = fdopendir(dirfd);
+   if (D == nullptr)
+      return _error->Errno("opendir",_("Unable to read %s"),CD.c_str());
+
+   /* Run over the directory, we assume that the reader order will never
+      change as the media is read-only. In theory if the kernel did
+      some sort of wacked caching this might not be true.. */
+   for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+   {
+      // Skip some files..
+      if (strcmp(Dir->d_name,".") == 0 ||
+	  strcmp(Dir->d_name,"..") == 0)
+	 continue;
+
+      std::string S;
+      if (Version <= 1)
+	 S = std::to_string(Dir->d_ino);
+      else
+      {
+	 struct stat Buf;
+	 if (fstatat(dirfd, Dir->d_name, &Buf, 0) != 0)
+	    continue;
+	 S = std::to_string(Buf.st_mtime);
+      }
+
+      Hash.Add(S.c_str());
+      Hash.Add(Dir->d_name);
+   }
+
+   // Some stats from the fsys
+   std::string S;
+   if (_config->FindB("Debug::identcdrom",false) == false)
+   {
+      struct statvfs Buf;
+      if (fstatvfs(dirfd, &Buf) != 0)
+	 return _error->Errno("statfs",_("Failed to stat the cdrom"));
+
+      // We use a kilobyte block size to avoid overflow
+      S = std::to_string(Buf.f_blocks * (Buf.f_bsize / 1024));
+      if (writable_media == false)
+	 S.append(" ").append(std::to_string(Buf.f_bfree * (Buf.f_bsize / 1024)));
+      Hash.Add(S.c_str(), S.length());
+      strprintf(S, "-%u", Version);
+   }
+   else
+      strprintf(S, "-%u.debug", Version);
+
+   closedir(D);
+   Res = Hash.GetHashString(Hashes::MD5SUM).HashValue().append(std::move(S));
+   return true;
+}
+									/*}}}*/
+// FindMountPointForDevice - Find mountpoint for the given device	/*{{{*/
+string FindMountPointForDevice(const char *devnode)
+{
+   // this is the order that mount uses as well
+   std::vector<std::string> const mounts = _config->FindVector("Dir::state::MountPoints", "/etc/mtab,/proc/mount");
+
+   for (std::vector<std::string>::const_iterator m = mounts.begin(); m != mounts.end(); ++m)
+      if (FileExists(*m) == true)
+      {
+	 char * line = NULL;
+	 size_t line_len = 0;
+	 FILE * f = fopen(m->c_str(), "r");
+	 while(getline(&line, &line_len, f) != -1)
+	 {
+	    char * out[] = { NULL, NULL, NULL };
+	    TokSplitString(' ', line, out, 3);
+	    if (out[2] != NULL || out[1] == NULL || out[0] == NULL)
+	       continue;
+	    if (strcmp(out[0], devnode) != 0)
+	       continue;
+	    fclose(f);
+	    // unescape the \0XXX chars in the path
+	    string mount_point = out[1];
+	    free(line);
+	    return DeEscapeString(mount_point);
+	 }
+	 fclose(f);
+	 free(line);
+      }
+
+   return string();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/cdromutl.h b/apt-pkg/contrib/cdromutl.h
new file mode 100644
index 0000000..1384cea
--- /dev/null
+++ b/apt-pkg/contrib/cdromutl.h
@@ -0,0 +1,24 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   CDROM Utilities - Some functions to manipulate CDROM mounts.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CDROMUTL_H
+#define PKGLIB_CDROMUTL_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+
+
+// mount cdrom, DeviceName (e.g. /dev/sr0) is optional
+APT_PUBLIC bool MountCdrom(std::string Path, std::string DeviceName="");
+APT_PUBLIC bool UnmountCdrom(std::string Path);
+APT_PUBLIC bool IdentCdrom(std::string CD,std::string &Res,unsigned int Version = 2);
+APT_PUBLIC bool IsMounted(std::string &Path);
+APT_PUBLIC std::string FindMountPointForDevice(const char *device);
+
+#endif
diff --git a/apt-pkg/contrib/cmndline.cc b/apt-pkg/contrib/cmndline.cc
new file mode 100644
index 0000000..998af2f
--- /dev/null
+++ b/apt-pkg/contrib/cmndline.cc
@@ -0,0 +1,445 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Command Line Class - Sophisticated command line parser
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cmndline.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/strutl.h>
+
+#include <string>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+// CommandLine::CommandLine - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+CommandLine::CommandLine(Args *AList,Configuration *Conf) : ArgList(AList), 
+                                 Conf(Conf), FileList(0)
+{
+}
+CommandLine::CommandLine() : ArgList(NULL), Conf(NULL), FileList(0)
+{
+}
+									/*}}}*/
+// CommandLine::~CommandLine - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+CommandLine::~CommandLine()
+{
+   delete [] FileList;
+}
+									/*}}}*/
+// CommandLine::GetCommand - return the first non-option word		/*{{{*/
+char const * CommandLine::GetCommand(Dispatch const * const Map,
+      unsigned int const argc, char const * const * const argv)
+{
+   // if there is a -- on the line there must be the word we search for either
+   // before it (as -- marks the end of the options) or right after it (as we can't
+   // decide if the command is actually an option, given that in theory, you could
+   // have parameters named like commands)
+   for (size_t i = 1; i < argc; ++i)
+   {
+      if (strcmp(argv[i], "--") != 0)
+	 continue;
+      // check if command is before --
+      for (size_t k = 1; k < i; ++k)
+	 for (size_t j = 0; Map[j].Match != NULL; ++j)
+	    if (strcmp(argv[k], Map[j].Match) == 0)
+	       return Map[j].Match;
+      // see if the next token after -- is the command
+      ++i;
+      if (i < argc)
+	 for (size_t j = 0; Map[j].Match != NULL; ++j)
+	    if (strcmp(argv[i], Map[j].Match) == 0)
+	       return Map[j].Match;
+      // we found a --, but not a command
+      return NULL;
+   }
+   // no --, so search for the first word matching a command
+   // FIXME: How like is it that an option parameter will be also a valid Match ?
+   for (size_t i = 1; i < argc; ++i)
+   {
+      if (*(argv[i]) == '-')
+	 continue;
+      for (size_t j = 0; Map[j].Match != NULL; ++j)
+	 if (strcmp(argv[i], Map[j].Match) == 0)
+	    return Map[j].Match;
+   }
+   return NULL;
+}
+									/*}}}*/
+// CommandLine::Parse - Main action member				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool CommandLine::Parse(int argc,const char **argv)
+{
+   delete [] FileList;
+   FileList = new const char *[argc];
+   const char **Files = FileList;
+   int I;
+   for (I = 1; I != argc; I++)
+   {
+      const char *Opt = argv[I];
+      
+      // It is not an option
+      if (*Opt != '-')
+      {
+	 *Files++ = Opt;
+	 continue;
+      }
+      
+      Opt++;
+      
+      // Double dash signifies the end of option processing
+      if (*Opt == '-' && Opt[1] == 0)
+      {
+	 I++;
+	 break;
+      }
+      
+      // Single dash is a short option
+      if (*Opt != '-')
+      {
+	 // Iterate over each letter
+	 while (*Opt != 0)
+	 {	    
+	    // Search for the option
+	    Args *A;
+	    for (A = ArgList; A->end() == false && A->ShortOpt != *Opt; A++);
+	    if (A->end() == true)
+	       return _error->Error(_("Command line option '%c' [from %s] is not understood in combination with the other options."),*Opt,argv[I]);
+
+	    if (HandleOpt(I,argc,argv,Opt,A) == false)
+	       return false;
+	    if (*Opt != 0)
+	       Opt++;	       
+	 }
+	 continue;
+      }
+      
+      Opt++;
+
+      // Match up to a = against the list
+      Args *A;
+      const char *OptEnd = strchrnul(Opt, '=');
+      for (A = ArgList; A->end() == false &&
+	   (A->LongOpt == 0 || stringcasecmp(Opt,OptEnd,A->LongOpt) != 0);
+	   ++A);
+      
+      // Failed, look for a word after the first - (no-foo)
+      bool PreceedMatch = false;
+      if (A->end() == true)
+      {
+         Opt = (const char*) memchr(Opt, '-', OptEnd - Opt);
+	 if (Opt == NULL)
+	    return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+	 Opt++;
+	 
+	 for (A = ArgList; A->end() == false &&
+	      (A->LongOpt == 0 || stringcasecmp(Opt,OptEnd,A->LongOpt) != 0);
+	      ++A);
+
+	 // Failed again..
+	 if (A->end() == true && OptEnd - Opt != 1)
+	    return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+
+	 // The option could be a single letter option prefixed by a no-..
+	 if (A->end() == true)
+	 {
+	    for (A = ArgList; A->end() == false && A->ShortOpt != *Opt; A++);
+	    
+	    if (A->end() == true)
+	       return _error->Error(_("Command line option %s is not understood in combination with the other options"),argv[I]);
+	 }
+	 
+	 // The option is not boolean
+	 if (A->IsBoolean() == false)
+	    return _error->Error(_("Command line option %s is not boolean"),argv[I]);
+	 PreceedMatch = true;
+      }
+      
+      // Deal with it.
+      OptEnd--;
+      if (HandleOpt(I,argc,argv,OptEnd,A,PreceedMatch) == false)
+	 return false;
+   }
+   
+   // Copy any remaining file names over
+   for (; I != argc; I++)
+      *Files++ = argv[I];
+   *Files = 0;
+
+   SaveInConfig(argc, argv);
+
+   return true;
+}
+									/*}}}*/
+// CommandLine::HandleOpt - Handle a single option including all flags	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a helper function for parser, it looks at a given argument
+   and looks for specific patterns in the string, it gets tokanized
+   -ruffly- like -*[yes|true|enable]-(o|longopt)[=][ ][argument] */
+bool CommandLine::HandleOpt(int &I,int argc,const char *argv[],
+			    const char *&Opt,Args *A,bool PreceedMatch)
+{
+   const char *Argument = 0;
+   bool CertainArg = false;
+   int IncI = 0;
+
+   /* Determine the possible location of an option or 0 if their is
+      no option */
+   if (Opt[1] == 0)
+   {
+      if (I + 1 < argc && argv[I+1][0] != '-')
+	 Argument = argv[I+1];
+
+      IncI = 1;
+   }
+   else
+   {
+      if (Opt[1] == '=')
+      {
+	 CertainArg = true;
+	 Argument = Opt + 2;
+      }      
+      else
+	 Argument = Opt + 1;
+   }
+   
+   // Option is an argument set
+   if ((A->Flags & HasArg) == HasArg)
+   {
+      if (Argument == 0)
+	 return _error->Error(_("Option %s requires an argument."),argv[I]);
+      Opt += strlen(Opt);
+      I += IncI;
+      
+      // Parse a configuration file
+      if ((A->Flags & ConfigFile) == ConfigFile)
+	 return ReadConfigFile(*Conf,Argument);
+
+      // Arbitrary item specification
+      if ((A->Flags & ArbItem) == ArbItem)
+      {
+	 const char * const J = strchr(Argument, '=');
+	 if (J == nullptr)
+	    return _error->Error(_("Option %s: Configuration item specification must have an =<val>."),argv[I]);
+
+	 Conf->Set(string(Argument,J-Argument), J+1);
+	 return true;
+      }
+      
+      const char *I = strchrnul(A->ConfName, ' ');
+      if (*I == ' ')
+	 Conf->Set(string(A->ConfName,0,I-A->ConfName),string(I+1) + Argument);
+      else
+	 Conf->Set(A->ConfName,string(I) + Argument);
+	 
+      return true;
+   }
+   
+   // Option is an integer level
+   if ((A->Flags & IntLevel) == IntLevel)
+   {
+      // There might be an argument
+      if (Argument != 0)
+      {
+	 char *EndPtr;
+	 unsigned long Value = strtol(Argument,&EndPtr,10);
+	 
+	 // Conversion failed and the argument was specified with an =s
+	 if (EndPtr == Argument && CertainArg == true)
+	    return _error->Error(_("Option %s requires an integer argument, not '%s'"),argv[I],Argument);
+
+	 // Conversion was ok, set the value and return
+	 if (EndPtr != 0 && EndPtr != Argument && *EndPtr == 0)
+	 {
+	    Conf->Set(A->ConfName,Value);
+	    Opt += strlen(Opt);
+	    I += IncI;
+	    return true;
+	 }	 
+      }      
+      
+      // Increase the level
+      Conf->Set(A->ConfName,Conf->FindI(A->ConfName)+1);
+      return true;
+   }
+  
+   // Option is a boolean
+   int Sense = -1;  // -1 is unspecified, 0 is yes 1 is no
+
+   // Look for an argument.
+   while (1)
+   {
+      // Look at preceding text
+      char Buffer[300];
+      if (Argument == 0)
+      {
+	 if (PreceedMatch == false)
+	    break;
+	 
+	 if (strlen(argv[I]) >= sizeof(Buffer))
+	    return _error->Error(_("Option '%s' is too long"),argv[I]);
+
+	 // Skip the leading dash
+	 const char *J = argv[I];
+	 for (; *J == '-'; J++)
+	    ;
+
+	 const char *JEnd = strchr(J, '-');
+	 if (JEnd != NULL)
+	 {
+	    strncpy(Buffer,J,JEnd - J);
+	    Buffer[JEnd - J] = 0;
+	    Argument = Buffer;
+	    CertainArg = true;
+	 }	 
+	 else
+	    break;
+      }
+
+      // Check for boolean
+      Sense = StringToBool(Argument);
+      if (Sense >= 0)
+      {
+	 // Eat the argument	 
+	 if (Argument != Buffer)
+	 {
+	    Opt += strlen(Opt);
+	    I += IncI;
+	 }	 
+	 break;
+      }
+
+      if (CertainArg == true)
+	 return _error->Error(_("Sense %s is not understood, try true or false."),Argument);
+      
+      Argument = 0;
+   }
+      
+   // Indeterminate sense depends on the flag
+   if (Sense == -1)
+   {
+      if ((A->Flags & InvBoolean) == InvBoolean)
+	 Sense = 0;
+      else
+	 Sense = 1;
+   }
+   
+   Conf->Set(A->ConfName,Sense);
+   return true;
+}
+									/*}}}*/
+// CommandLine::FileSize - Count the number of filenames		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned int CommandLine::FileSize() const
+{
+   unsigned int Count = 0;
+   for (const char **I = FileList; I != 0 && *I != 0; I++)
+      Count++;
+   return Count;
+}
+									/*}}}*/
+// CommandLine::DispatchArg - Do something with the first arg		/*{{{*/
+bool CommandLine::DispatchArg(Dispatch const * const Map,bool NoMatch)
+{
+   int I;
+   for (I = 0; Map[I].Match != 0; I++)
+   {
+      if (strcmp(FileList[0],Map[I].Match) == 0)
+      {
+	 bool Res = Map[I].Handler(*this);
+	 if (Res == false && _error->PendingError() == false)
+	    _error->Error("Handler silently failed");
+	 return Res;
+      }
+   }
+   
+   // No matching name
+   if (Map[I].Match == 0)
+   {
+      if (NoMatch == true)
+	 _error->Error(_("Invalid operation %s"),FileList[0]);
+   }
+   
+   return false;
+}
+									/*}}}*/
+// CommandLine::SaveInConfig - for output later in a logfile or so	/*{{{*/
+// ---------------------------------------------------------------------
+/* We save the commandline here to have it around later for e.g. logging.
+   It feels a bit like a hack here and isn't bulletproof, but it is better
+   than nothing after all. */
+void CommandLine::SaveInConfig(unsigned int const &argc, char const * const * const argv)
+{
+   char cmdline[100 + argc * 50];
+   memset(cmdline, 0, sizeof(cmdline));
+   unsigned int length = 0;
+   bool lastWasOption = false;
+   bool closeQuote = false;
+   for (unsigned int i = 0; i < argc && length < sizeof(cmdline); ++i, ++length)
+   {
+      for (unsigned int j = 0; argv[i][j] != '\0' && length < sizeof(cmdline)-2; ++j)
+      {
+	 // we can't really sensibly deal with quoting so skip it
+	 if (strchr("\"\'\r\n", argv[i][j]) != nullptr)
+	    continue;
+	 cmdline[length++] = argv[i][j];
+	 if (lastWasOption == true && argv[i][j] == '=')
+	 {
+	    // That is possibly an option: Quote it if it includes spaces,
+	    // the benefit is that this will eliminate also most false positives
+	    const char* c = strchr(&argv[i][j+1], ' ');
+	    if (c == NULL) continue;
+	    cmdline[length++] = '\'';
+	    closeQuote = true;
+	 }
+      }
+      if (closeQuote == true)
+      {
+	 cmdline[length++] = '\'';
+	 closeQuote = false;
+      }
+      // Problem: detects also --hello
+      if (cmdline[length-1] == 'o')
+	 lastWasOption = true;
+      cmdline[length] = ' ';
+   }
+   cmdline[--length] = '\0';
+   _config->Set("CommandLine::AsString", cmdline);
+}
+									/*}}}*/
+CommandLine::Args CommandLine::MakeArgs(char ShortOpt, char const *LongOpt, char const *ConfName, unsigned long Flags)/*{{{*/
+{
+   /* In theory, this should be a constructor for CommandLine::Args instead,
+      but this breaks compatibility as gcc thinks this is a c++11 initializer_list */
+   CommandLine::Args arg;
+   arg.ShortOpt = ShortOpt;
+   arg.LongOpt = LongOpt;
+   arg.ConfName = ConfName;
+   arg.Flags = Flags;
+   return arg;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/cmndline.h b/apt-pkg/contrib/cmndline.h
new file mode 100644
index 0000000..40d384f
--- /dev/null
+++ b/apt-pkg/contrib/cmndline.h
@@ -0,0 +1,113 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Command Line Class - Sophisticated command line parser
+   
+   This class provides a unified command line parser/option handliner/
+   configuration mechanism. It allows the caller to specify the option
+   set and map the option set into the configuration class or other
+   special functioning.
+   
+   Filenames are stripped from the option stream and put into their
+   own array.
+   
+   The argument descriptor array can be initialized as:
+   
+ CommandLine::Args Args[] = 
+ {{'q',"quiet","apt::get::quiet",CommandLine::IntLevel},
+  {0,0,0,0}};
+   
+   The flags mean,
+     HasArg - Means the argument has a value
+     IntLevel - Means the argument is an integer level indication, the
+                following -qqqq (+3) -q5 (=5) -q=5 (=5) are valid
+     Boolean  - Means it is true/false or yes/no. 
+                -d (true) --no-d (false) --yes-d (true)
+                --long (true) --no-long (false) --yes-long (true)
+                -d=yes (true) -d=no (false) Words like enable, disable,
+                true false, yes no and on off are recognized in logical 
+                places.
+     InvBoolean - Same as boolean but the case with no specified sense
+                  (first case) is set to false.
+     ConfigFile - Means this flag should be interprited as the name of 
+                  a config file to read in at this point in option processing.
+                  Implies HasArg.
+     ArbItem    - Means the item is an arbitrary configuration string of
+                  the form item=value, where item is passed directly
+                  to the configuration class.
+   The default, if the flags are 0 is to use Boolean
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CMNDLINE_H
+#define PKGLIB_CMNDLINE_H
+
+#include <apt-pkg/macros.h>
+
+
+class Configuration;
+
+class APT_PUBLIC CommandLine
+{
+   public:
+   struct Args;
+   struct Dispatch;
+   struct DispatchWithHelp;
+   
+   protected:
+   
+   Args *ArgList;
+   Configuration *Conf;
+   bool HandleOpt(int &I,int argc,const char *argv[],
+		  const char *&Opt,Args *A,bool PreceedeMatch = false);
+   void static SaveInConfig(unsigned int const &argc, char const * const * const argv);
+
+   public:
+   
+   enum AFlags 
+   {
+      HasArg = (1 << 0),
+      IntLevel = (1 << 1),
+      Boolean = (1 << 2),
+      InvBoolean = (1 << 3),
+      ConfigFile = (1 << 4) | HasArg,
+      ArbItem = (1 << 5) | HasArg
+   };
+
+   const char **FileList;
+   
+   bool Parse(int argc,const char **argv);
+   void ShowHelp();
+   unsigned int FileSize() const APT_PURE;
+   bool DispatchArg(Dispatch const * const List,bool NoMatch = true);
+      
+   static char const * GetCommand(Dispatch const * const Map,
+	 unsigned int const argc, char const * const * const argv) APT_PURE;
+
+   static CommandLine::Args MakeArgs(char ShortOpt, char const *LongOpt,
+	 char const *ConfName, unsigned long Flags) APT_PURE;
+
+   CommandLine();
+   CommandLine(Args *AList,Configuration *Conf);
+   ~CommandLine();
+};
+
+struct CommandLine::Args
+{
+   char ShortOpt;
+   const char *LongOpt;
+   const char *ConfName;
+   unsigned long Flags;
+   
+   inline bool end() {return ShortOpt == 0 && LongOpt == 0;};
+   inline bool IsBoolean() {return Flags == 0 || (Flags & (Boolean|InvBoolean)) != 0;};
+};
+
+struct CommandLine::Dispatch
+{
+   const char *Match;
+   bool (*Handler)(CommandLine &);
+};
+
+#endif
diff --git a/apt-pkg/contrib/configuration.cc b/apt-pkg/contrib/configuration.cc
new file mode 100644
index 0000000..1134ed6
--- /dev/null
+++ b/apt-pkg/contrib/configuration.cc
@@ -0,0 +1,1194 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Configuration Class
+   
+   This class provides a configuration file and command line parser
+   for a tree-oriented configuration environment. All runtime configuration
+   is stored in here.
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+
+   ##################################################################### */
+									/*}}}*/
+// Include files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/string_view.h>
+
+#include <ctype.h>
+#include <regex.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <algorithm>
+#include <array>
+#include <fstream>
+#include <iterator>
+#include <numeric>
+#include <sstream>
+#include <stack>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include <apti18n.h>
+
+using namespace std;
+									/*}}}*/
+
+Configuration *_config = new Configuration;
+
+/* TODO: This config verification shouldn't be using a static variable
+   but a Cnf-member – but that would need ABI breaks and stuff and for now
+   that really is an apt-dev-only tool, so it isn't that bad that it is
+   unusable and allaround a bit strange */
+enum class APT_HIDDEN ConfigType { UNDEFINED, INT, BOOL, STRING, STRING_OR_BOOL, STRING_OR_LIST, FILE, DIR, LIST, PROGRAM_PATH = FILE };
+APT_HIDDEN std::unordered_map<std::string, ConfigType> apt_known_config {};
+static std::string getConfigTypeString(ConfigType const type)		/*{{{*/
+{
+   switch (type)
+   {
+      case ConfigType::UNDEFINED: return "UNDEFINED";
+      case ConfigType::INT: return "INT";
+      case ConfigType::BOOL: return "BOOL";
+      case ConfigType::STRING: return "STRING";
+      case ConfigType::STRING_OR_BOOL: return "STRING_OR_BOOL";
+      case ConfigType::FILE: return "FILE";
+      case ConfigType::DIR: return "DIR";
+      case ConfigType::LIST: return "LIST";
+      case ConfigType::STRING_OR_LIST: return "STRING_OR_LIST";
+   }
+   return "UNKNOWN";
+}
+									/*}}}*/
+static ConfigType getConfigType(std::string const &type)		/*{{{*/
+{
+   if (type == "<INT>")
+      return ConfigType::INT;
+   else if (type == "<BOOL>")
+      return ConfigType::BOOL;
+   else if (type == "<STRING>")
+      return ConfigType::STRING;
+   else if (type == "<STRING_OR_BOOL>")
+      return ConfigType::STRING_OR_BOOL;
+   else if (type == "<FILE>")
+      return ConfigType::FILE;
+   else if (type == "<DIR>")
+      return ConfigType::DIR;
+   else if (type == "<LIST>")
+      return ConfigType::LIST;
+   else if (type == "<STRING_OR_LIST>")
+      return ConfigType::STRING_OR_LIST;
+   else if (type == "<PROGRAM_PATH>")
+      return ConfigType::PROGRAM_PATH;
+   return ConfigType::UNDEFINED;
+}
+									/*}}}*/
+// checkFindConfigOptionType - workhorse of option checking		/*{{{*/
+static void checkFindConfigOptionTypeInternal(std::string name, ConfigType const type)
+{
+   std::transform(name.begin(), name.end(), name.begin(), ::tolower);
+   auto known = apt_known_config.find(name);
+   if (known == apt_known_config.cend())
+   {
+      auto const rcolon = name.rfind(':');
+      if (rcolon != std::string::npos)
+      {
+	 known = apt_known_config.find(name.substr(0, rcolon) + ":*");
+	 if (known == apt_known_config.cend())
+	 {
+	    auto const parts = StringSplit(name, "::");
+	    size_t psize = parts.size();
+	    if (psize > 1)
+	    {
+	       for (size_t max = psize; max != 1; --max)
+	       {
+		  std::ostringstream os;
+		  std::copy(parts.begin(), parts.begin() + max, std::ostream_iterator<std::string>(os, "::"));
+		  os << "**";
+		  known = apt_known_config.find(os.str());
+		  if (known != apt_known_config.cend() && known->second == ConfigType::UNDEFINED)
+		     return;
+	       }
+	       for (size_t max = psize - 1; max != 1; --max)
+	       {
+		  std::ostringstream os;
+		  std::copy(parts.begin(), parts.begin() + max - 1, std::ostream_iterator<std::string>(os, "::"));
+		  os << "*::";
+		  std::copy(parts.begin() + max + 1, parts.end() - 1, std::ostream_iterator<std::string>(os, "::"));
+		  os << *(parts.end() - 1);
+		  known = apt_known_config.find(os.str());
+		  if (known != apt_known_config.cend())
+		     break;
+	       }
+	    }
+	 }
+      }
+   }
+   if (known == apt_known_config.cend())
+      _error->Warning("Using unknown config option »%s« of type %s",
+	    name.c_str(), getConfigTypeString(type).c_str());
+   else if (known->second != type)
+   {
+      if (known->second == ConfigType::DIR && type == ConfigType::FILE)
+	 ; // implementation detail
+      else if (type == ConfigType::STRING && (known->second == ConfigType::FILE || known->second == ConfigType::DIR))
+	 ; // TODO: that might be an error or not, we will figure this out later
+      else if (known->second == ConfigType::STRING_OR_BOOL && (type == ConfigType::BOOL || type == ConfigType::STRING))
+	 ;
+      else if (known->second == ConfigType::STRING_OR_LIST && (type == ConfigType::LIST || type == ConfigType::STRING))
+	 ;
+      else
+	 _error->Warning("Using config option »%s« of type %s as a type %s",
+	       name.c_str(), getConfigTypeString(known->second).c_str(), getConfigTypeString(type).c_str());
+   }
+}
+static void checkFindConfigOptionType(char const * const name, ConfigType const type)
+{
+   if (apt_known_config.empty())
+      return;
+   checkFindConfigOptionTypeInternal(name, type);
+}
+									/*}}}*/
+static bool LoadConfigurationIndex(std::string const &filename)		/*{{{*/
+{
+   apt_known_config.clear();
+   if (filename.empty())
+      return true;
+   Configuration Idx;
+   if (ReadConfigFile(Idx, filename) == false)
+      return false;
+
+   Configuration::Item const * Top = Idx.Tree(nullptr);
+   if (unlikely(Top == nullptr))
+      return false;
+
+   do {
+      if (Top->Value.empty() == false)
+      {
+	 std::string fulltag = Top->FullTag();
+	 std::transform(fulltag.begin(), fulltag.end(), fulltag.begin(), ::tolower);
+	 apt_known_config.emplace(std::move(fulltag), getConfigType(Top->Value));
+      }
+
+      if (Top->Child != nullptr)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != nullptr && Top->Next == nullptr)
+	 Top = Top->Parent;
+      if (Top != nullptr)
+	 Top = Top->Next;
+   } while (Top != nullptr);
+
+   return true;
+}
+									/*}}}*/
+
+// Configuration::Configuration - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+Configuration::Configuration() : ToFree(true)
+{
+   Root = new Item;
+}
+Configuration::Configuration(const Item *Root) : Root((Item *)Root), ToFree(false)
+{
+}
+									/*}}}*/
+// Configuration::~Configuration - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+Configuration::~Configuration()
+{
+   if (ToFree == false)
+      return;
+   
+   Item *Top = Root;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+            
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Item *Parent = Top->Parent;
+	 delete Top;
+	 Top = Parent;
+      }      
+      if (Top != 0)
+      {
+	 Item *Next = Top->Next;
+	 delete Top;
+	 Top = Next;
+      }
+   }
+}
+									/*}}}*/
+// Configuration::Lookup - Lookup a single item				/*{{{*/
+// ---------------------------------------------------------------------
+/* This will lookup a single item by name below another item. It is a 
+   helper function for the main lookup function */
+Configuration::Item *Configuration::Lookup(Item *Head,const char *S,
+					   unsigned long const &Len,bool const &Create)
+{
+   int Res = 1;
+   Item *I = Head->Child;
+   Item **Last = &Head->Child;
+   
+   // Empty strings match nothing. They are used for lists.
+   if (Len != 0)
+   {
+      for (; I != 0; Last = &I->Next, I = I->Next)
+	 if (Len == I->Tag.length() && (Res = stringcasecmp(I->Tag,S,S + Len)) == 0)
+	    break;
+   }
+   else
+      for (; I != 0; Last = &I->Next, I = I->Next);
+      
+   if (Res == 0)
+      return I;
+   if (Create == false)
+      return 0;
+   
+   I = new Item;
+   I->Tag.assign(S,Len);
+   I->Next = *Last;
+   I->Parent = Head;
+   *Last = I;
+   return I;
+}
+									/*}}}*/
+// Configuration::Lookup - Lookup a fully scoped item			/*{{{*/
+// ---------------------------------------------------------------------
+/* This performs a fully scoped lookup of a given name, possibly creating
+   new items */
+Configuration::Item *Configuration::Lookup(const char *Name,bool const &Create)
+{
+   if (Name == 0)
+      return Root->Child;
+   
+   const char *Start = Name;
+   const char *End = Start + strlen(Name);
+   const char *TagEnd = Name;
+   Item *Itm = Root;
+   for (; End - TagEnd >= 2; TagEnd++)
+   {
+      if (TagEnd[0] == ':' && TagEnd[1] == ':')
+      {
+	 Itm = Lookup(Itm,Start,TagEnd - Start,Create);
+	 if (Itm == 0)
+	    return 0;
+	 TagEnd = Start = TagEnd + 2;	 
+      }
+   }   
+
+   // This must be a trailing ::, we create unique items in a list
+   if (End - Start == 0)
+   {
+      if (Create == false)
+	 return 0;
+   }
+   
+   Itm = Lookup(Itm,Start,End - Start,Create);
+   return Itm;
+}
+									/*}}}*/
+// Configuration::Find - Find a value					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string Configuration::Find(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::STRING);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+   {
+      if (Default == 0)
+	 return "";
+      else
+	 return Default;
+   }
+   
+   return Itm->Value;
+}
+									/*}}}*/
+// Configuration::FindFile - Find a Filename				/*{{{*/
+// ---------------------------------------------------------------------
+/* Directories are stored as the base dir in the Parent node and the
+   sub directory in sub nodes with the final node being the end filename
+ */
+string Configuration::FindFile(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::FILE);
+   const Item *RootItem = Lookup("RootDir");
+   std::string result =  (RootItem == 0) ? "" : RootItem->Value;
+   if(result.empty() == false && result[result.size() - 1] != '/')
+     result.push_back('/');
+
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+   {
+      if (Default != 0)
+	 result.append(Default);
+   }
+   else
+   {
+      string val = Itm->Value;
+      while (Itm->Parent != 0)
+      {
+	 if (Itm->Parent->Value.empty() == true)
+	 {
+	    Itm = Itm->Parent;
+	    continue;
+	 }
+
+	 // Absolute
+	 if (val.length() >= 1 && val[0] == '/')
+	 {
+	    if (val.compare(0, 9, "/dev/null") == 0)
+	       val.erase(9);
+	    break;
+	 }
+
+	 // ~/foo or ./foo
+	 if (val.length() >= 2 && (val[0] == '~' || val[0] == '.') && val[1] == '/')
+	    break;
+
+	 // ../foo
+	 if (val.length() >= 3 && val[0] == '.' && val[1] == '.' && val[2] == '/')
+	    break;
+
+	 if (Itm->Parent->Value.end()[-1] != '/')
+	    val.insert(0, "/");
+
+	 val.insert(0, Itm->Parent->Value);
+	 Itm = Itm->Parent;
+      }
+      result.append(val);
+   }
+   return flNormalize(result);
+}
+									/*}}}*/
+// Configuration::FindDir - Find a directory name			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is like findfile execept the result is terminated in a / */
+string Configuration::FindDir(const char *Name,const char *Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::DIR);
+   string Res = FindFile(Name,Default);
+   if (Res.end()[-1] != '/')
+   {
+      size_t const found = Res.rfind("/dev/null");
+      if (found != string::npos && found == Res.size() - 9)
+	 return Res; // /dev/null returning
+      return Res + '/';
+   }
+   return Res;
+}
+									/*}}}*/
+// Configuration::FindVector - Find a vector of values			/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns a vector of config values under the given item */
+vector<string> Configuration::FindVector(const char *Name, std::string const &Default, bool const Keys) const
+{
+   checkFindConfigOptionType(Name, ConfigType::LIST);
+   vector<string> Vec;
+   const Item *Top = Lookup(Name);
+   if (Top == NULL)
+      return VectorizeString(Default, ',');
+
+   if (Top->Value.empty() == false)
+      return VectorizeString(Top->Value, ',');
+
+   Item *I = Top->Child;
+   while(I != NULL)
+   {
+      Vec.push_back(Keys ? I->Tag : I->Value);
+      I = I->Next;
+   }
+   if (Vec.empty() == true)
+      return VectorizeString(Default, ',');
+
+   return Vec;
+}
+									/*}}}*/
+// Configuration::FindI - Find an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+int Configuration::FindI(const char *Name,int const &Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::INT);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+      return Default;
+   
+   char *End;
+   int Res = strtol(Itm->Value.c_str(),&End,0);
+   if (End == Itm->Value.c_str())
+      return Default;
+   
+   return Res;
+}
+									/*}}}*/
+// Configuration::FindB - Find a boolean type				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool Configuration::FindB(const char *Name,bool const &Default) const
+{
+   checkFindConfigOptionType(Name, ConfigType::BOOL);
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0 || Itm->Value.empty() == true)
+      return Default;
+   
+   return StringToBool(Itm->Value,Default);
+}
+									/*}}}*/
+// Configuration::FindAny - Find an arbitrary type			/*{{{*/
+// ---------------------------------------------------------------------
+/* a key suffix of /f, /d, /b or /i calls Find{File,Dir,B,I} */
+string Configuration::FindAny(const char *Name,const char *Default) const
+{
+   string key = Name;
+   char type = 0;
+
+   if (key.size() > 2 && key.end()[-2] == '/')
+   {
+      type = key.end()[-1];
+      key.resize(key.size() - 2);
+   }
+
+   switch (type)
+   {
+      // file
+      case 'f': 
+      return FindFile(key.c_str(), Default);
+      
+      // directory
+      case 'd': 
+      return FindDir(key.c_str(), Default);
+      
+      // bool
+      case 'b': 
+      return FindB(key, Default) ? "true" : "false";
+      
+      // int
+      case 'i': 
+      {
+	 char buf[16];
+	 snprintf(buf, sizeof(buf)-1, "%d", FindI(key, Default ? atoi(Default) : 0 ));
+	 return buf;
+      }
+   }
+
+   // fallback
+   return Find(Name, Default);
+}
+									/*}}}*/
+// Configuration::CndSet - Conditional Set a value			/*{{{*/
+// ---------------------------------------------------------------------
+/* This will not overwrite */
+void Configuration::CndSet(const char *Name,const string &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   if (Itm->Value.empty() == true)
+      Itm->Value = Value;
+}
+									/*}}}*/
+// Configuration::Set - Set an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::CndSet(const char *Name,int const Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0 || Itm->Value.empty() == false)
+      return;
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Itm->Value = S;
+}
+									/*}}}*/
+// Configuration::Set - Set a value					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Set(const char *Name,const string &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   Itm->Value = Value;
+}
+									/*}}}*/
+// Configuration::Set - Set an integer value				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Set(const char *Name,int const &Value)
+{
+   Item *Itm = Lookup(Name,true);
+   if (Itm == 0)
+      return;
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Itm->Value = S;
+}
+									/*}}}*/
+// Configuration::Clear - Clear an single value from a list	        /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name, int const &Value)
+{
+   char S[300];
+   snprintf(S,sizeof(S),"%i",Value);
+   Clear(Name, S);
+}
+									/*}}}*/
+// Configuration::Clear - Clear an single value from a list	        /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name, string const &Value)
+{
+   Item *Top = Lookup(Name.c_str(),false);
+   if (Top == 0 || Top->Child == 0)
+      return;
+
+   Item *Tmp, *Prev, *I;
+   Prev = I = Top->Child;
+
+   while(I != NULL)
+   {
+      if(I->Value == Value)
+      {
+	 Tmp = I;
+	 // was first element, point parent to new first element
+	 if(Top->Child == Tmp)
+	    Top->Child = I->Next;
+	 I = I->Next;
+	 Prev->Next = I;
+	 delete Tmp;
+      } else {
+	 Prev = I;
+	 I = I->Next;
+      }
+   }
+     
+}
+									/*}}}*/
+// Configuration::Clear - Clear everything				/*{{{*/
+// ---------------------------------------------------------------------
+void Configuration::Clear()
+{
+   const Configuration::Item *Top = Tree(0);
+   while( Top != 0 )
+   {
+      Clear(Top->FullTag());
+      Top = Top->Next;
+   }
+}
+									/*}}}*/
+// Configuration::Clear - Clear an entire tree				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void Configuration::Clear(string const &Name)
+{
+   Item *Top = Lookup(Name.c_str(),false);
+   if (Top == 0) 
+      return;
+
+   Top->Value.clear();
+   Item *Stop = Top;
+   Top = Top->Child;
+   Stop->Child = 0;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Item *Tmp = Top;
+	 Top = Top->Parent;
+	 delete Tmp;
+	 
+	 if (Top == Stop)
+	    return;
+      }
+      
+      Item *Tmp = Top;
+      if (Top != 0)
+	 Top = Top->Next;
+      delete Tmp;
+   }
+}
+									/*}}}*/
+void Configuration::MoveSubTree(char const * const OldRootName, char const * const NewRootName)/*{{{*/
+{
+   // prevent NewRoot being a subtree of OldRoot
+   if (OldRootName == nullptr)
+      return;
+   if (NewRootName != nullptr)
+   {
+      if (strcmp(OldRootName, NewRootName) == 0)
+	 return;
+      std::string const oldroot = std::string(OldRootName) + "::";
+      if (strcasestr(NewRootName, oldroot.c_str()) != NULL)
+	 return;
+   }
+
+   Item * Top;
+   Item const * const OldRoot = Top = Lookup(OldRootName, false);
+   if (Top == nullptr)
+      return;
+   std::string NewRoot;
+   if (NewRootName != nullptr)
+      NewRoot.append(NewRootName).append("::");
+
+   Top->Value.clear();
+   Item * const Stop = Top;
+   Top = Top->Child;
+   Stop->Child = 0;
+   for (; Top != 0;)
+   {
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+      {
+	 Set(NewRoot + Top->FullTag(OldRoot), Top->Value);
+	 Item const * const Tmp = Top;
+	 Top = Top->Parent;
+	 delete Tmp;
+
+	 if (Top == Stop)
+	    return;
+      }
+
+      Set(NewRoot + Top->FullTag(OldRoot), Top->Value);
+      Item const * const Tmp = Top;
+      if (Top != 0)
+	 Top = Top->Next;
+      delete Tmp;
+   }
+}
+									/*}}}*/
+// Configuration::Exists - Returns true if the Name exists		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool Configuration::Exists(const char *Name) const
+{
+   const Item *Itm = Lookup(Name);
+   if (Itm == 0)
+      return false;
+   return true;
+}
+									/*}}}*/
+// Configuration::ExistsAny - Returns true if the Name, possibly	/*{{{*/
+// ---------------------------------------------------------------------
+/* qualified by /[fdbi] exists */
+bool Configuration::ExistsAny(const char *Name) const
+{
+   string key = Name;
+
+   if (key.size() > 2 && key.end()[-2] == '/')
+   {
+      if (key.find_first_of("fdbi",key.size()-1) < key.size())
+      {
+         key.resize(key.size() - 2);
+         if (Exists(key.c_str()))
+            return true;
+      }
+      else
+      {
+         _error->Warning(_("Unrecognized type abbreviation: '%c'"), key.end()[-3]);
+      }
+   }
+   return Exists(Name);
+}
+									/*}}}*/
+// Configuration::Dump - Dump the config				/*{{{*/
+// ---------------------------------------------------------------------
+/* Dump the entire configuration space */
+void Configuration::Dump(ostream& str)
+{
+   Dump(str, NULL, "%F \"%v\";\n", true);
+}
+void Configuration::Dump(ostream& str, char const * const root,
+			 char const * const formatstr, bool const emptyValue)
+{
+   const Configuration::Item* Top = Tree(root);
+   if (Top == 0)
+      return;
+   const Configuration::Item* const Root = (root == NULL) ? NULL : Top;
+   std::vector<std::string> const format = VectorizeString(formatstr, '%');
+
+   /* Write out all of the configuration directives by walking the
+      configuration tree */
+   do {
+      if (emptyValue == true || Top->Value.empty() == emptyValue)
+      {
+	 std::vector<std::string>::const_iterator f = format.begin();
+	 str << *f;
+	 for (++f; f != format.end(); ++f)
+	 {
+	    if (f->empty() == true)
+	    {
+	       ++f;
+	       str << '%' << *f;
+	       continue;
+	    }
+	    char const type = (*f)[0];
+	    if (type == 'f')
+	       str << Top->FullTag();
+	    else if (type == 't')
+	       str << Top->Tag;
+	    else if (type == 'v')
+	       str << Top->Value;
+	    else if (type == 'F')
+	       str << QuoteString(Top->FullTag(), "=\"\n");
+	    else if (type == 'T')
+	       str << QuoteString(Top->Tag, "=\"\n");
+	    else if (type == 'V')
+	       str << QuoteString(Top->Value, "=\"\n");
+	    else if (type == 'n')
+	       str << "\n";
+	    else if (type == 'N')
+	       str << "\t";
+	    else
+	       str << '%' << type;
+	    str << f->c_str() + 1;
+	 }
+      }
+
+      if (Top->Child != 0)
+      {
+	 Top = Top->Child;
+	 continue;
+      }
+
+      while (Top != 0 && Top->Next == 0)
+	 Top = Top->Parent;
+      if (Top != 0)
+	 Top = Top->Next;
+
+      if (Root != NULL)
+      {
+	 const Configuration::Item* I = Top;
+	 while(I != 0)
+	 {
+	    if (I == Root)
+	       break;
+	    else
+	       I = I->Parent;
+	 }
+	 if (I == 0)
+	    break;
+      }
+   } while (Top != 0);
+}
+									/*}}}*/
+
+// Configuration::Item::FullTag - Return the fully scoped tag		/*{{{*/
+// ---------------------------------------------------------------------
+/* Stop sets an optional max recursion depth if this item is being viewed as
+   part of a sub tree. */
+string Configuration::Item::FullTag(const Item *Stop) const
+{
+   if (Parent == 0 || Parent->Parent == 0 || Parent == Stop)
+      return Tag;
+   return Parent->FullTag(Stop) + "::" + Tag;
+}
+									/*}}}*/
+
+// ReadConfigFile - Read a configuration file				/*{{{*/
+// ---------------------------------------------------------------------
+/* The configuration format is very much like the named.conf format
+   used in bind8, in fact this routine can parse most named.conf files. 
+   Sectional config files are like bind's named.conf where there are 
+   sections like 'zone "foo.org" { .. };' This causes each section to be
+   added in with a tag like "zone::foo.org" instead of being split 
+   tag/value. AsSectional enables Sectional parsing.*/
+static void leaveCurrentScope(std::stack<std::string> &Stack, std::string &ParentTag)
+{
+   if (Stack.empty())
+      ParentTag.clear();
+   else
+   {
+      ParentTag = Stack.top();
+      Stack.pop();
+   }
+}
+bool ReadConfigFile(Configuration &Conf,const string &FName,bool const &AsSectional,
+		    unsigned const &Depth)
+{
+   // Open the stream for reading
+   FileFd F;
+   if (OpenConfigurationFileFd(FName, F) == false)
+      return false;
+
+   string LineBuffer;
+   std::stack<std::string> Stack;
+
+   // Parser state
+   string ParentTag;
+
+   int CurLine = 0;
+   bool InComment = false;
+   while (F.Eof() == false)
+   {
+      // The raw input line.
+      std::string Input;
+      if (F.ReadLine(Input) == false)
+	 Input.clear();
+      // The input line with comments stripped.
+      std::string Fragment;
+
+      // Expand tabs in the input line and remove leading and trailing whitespace.
+      Input = APT::String::Strip(SubstVar(Input, "\t", "        "));
+      CurLine++;
+
+      // Now strip comments; if the whole line is contained in a
+      // comment, skip this line.
+      APT::StringView Line{Input.data(), Input.size()};
+
+      // continued Multi line comment
+      if (InComment)
+      {
+	 size_t end = Line.find("*/");
+	 if (end != APT::StringView::npos)
+	 {
+	    Line.remove_prefix(end + 2);
+	    InComment = false;
+	 }
+	 else
+	    continue;
+      }
+
+      // Discard single line comments
+      {
+	 size_t start = 0;
+	 while ((start = Line.find("//", start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0)
+	    {
+	       ++start;
+	       continue;
+	    }
+	    Line.remove_suffix(Line.length() - start);
+	    break;
+	 }
+	 using APT::operator""_sv;
+	 constexpr std::array<APT::StringView, 3> magicComments { "clear"_sv, "include"_sv, "x-apt-configure-index"_sv };
+	 start = 0;
+	 while ((start = Line.find('#', start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0 ||
+		std::any_of(magicComments.begin(), magicComments.end(), [&](auto const m) { return Line.compare(start+1, m.length(), m) == 0; }))
+	    {
+	       ++start;
+	       continue;
+	    }
+	    Line.remove_suffix(Line.length() - start);
+	    break;
+	 }
+      }
+
+      // Look for multi line comments and build up the
+      // fragment.
+      Fragment.reserve(Line.length());
+      {
+	 size_t start = 0;
+	 while ((start = Line.find("/*", start)) != APT::StringView::npos)
+	 {
+	    if (std::count(Line.begin(), Line.begin() + start, '"') % 2 != 0)
+	    {
+	       start += 2;
+	       continue;
+	    }
+	    Fragment.append(Line.data(), start);
+	    auto const end = Line.find("*/", start + 2);
+	    if (end == APT::StringView::npos)
+	    {
+	       Line.clear();
+	       InComment = true;
+	       break;
+	    }
+	    else
+	       Line.remove_prefix(end + 2);
+	    start = 0;
+	 }
+	 if (not Line.empty())
+	    Fragment.append(Line.data(), Line.length());
+      }
+
+      // Skip blank lines.
+      if (Fragment.empty())
+	 continue;
+
+      // The line has actual content; interpret what it means.
+      bool InQuote = false;
+      auto Start = Fragment.cbegin();
+      auto End = Fragment.cend();
+      for (std::string::const_iterator I = Start;
+	   I != End; ++I)
+      {
+	 if (*I == '"')
+	    InQuote = !InQuote;
+
+	 if (InQuote == false && (*I == '{' || *I == ';' || *I == '}'))
+	 {
+	    // Put the last fragment into the buffer
+	    std::string::const_iterator NonWhitespaceStart = Start;
+	    std::string::const_iterator NonWhitespaceStop = I;
+	    for (; NonWhitespaceStart != I && isspace(*NonWhitespaceStart) != 0; ++NonWhitespaceStart)
+	      ;
+	    for (; NonWhitespaceStop != NonWhitespaceStart && isspace(NonWhitespaceStop[-1]) != 0; --NonWhitespaceStop)
+	      ;
+	    if (LineBuffer.empty() == false && NonWhitespaceStop - NonWhitespaceStart != 0)
+	       LineBuffer += ' ';
+	    LineBuffer += string(NonWhitespaceStart, NonWhitespaceStop);
+
+	    // Drop this from the input string, saving the character
+	    // that terminated the construct we just closed. (i.e., a
+	    // brace or a semicolon)
+	    char TermChar = *I;
+	    Start = I + 1;
+
+	    // Syntax Error
+	    if (TermChar == '{' && LineBuffer.empty() == true)
+	       return _error->Error(_("Syntax error %s:%u: Block starts with no name."),FName.c_str(),CurLine);
+
+	    // No string on this line
+	    if (LineBuffer.empty() == true)
+	    {
+	       if (TermChar == '}')
+		  leaveCurrentScope(Stack, ParentTag);
+	       continue;
+	    }
+
+	    // Parse off the tag
+	    string Tag;
+	    const char *Pos = LineBuffer.c_str();
+	    if (ParseQuoteWord(Pos,Tag) == false)
+	       return _error->Error(_("Syntax error %s:%u: Malformed tag"),FName.c_str(),CurLine);
+
+	    // Parse off the word
+	    string Word;
+	    bool NoWord = false;
+	    if (ParseCWord(Pos,Word) == false &&
+		ParseQuoteWord(Pos,Word) == false)
+	    {
+	       if (TermChar != '{')
+	       {
+		  Word = Tag;
+		  Tag = "";
+	       }
+	       else
+		  NoWord = true;
+	    }
+	    if (strlen(Pos) != 0)
+	       return _error->Error(_("Syntax error %s:%u: Extra junk after value"),FName.c_str(),CurLine);
+
+	    // Go down a level
+	    if (TermChar == '{')
+	    {
+	       Stack.push(ParentTag);
+
+	       /* Make sectional tags incorporate the section into the
+	          tag string */
+	       if (AsSectional == true && Word.empty() == false)
+	       {
+		  Tag.append("::").append(Word);
+		  Word.clear();
+	       }
+
+	       if (ParentTag.empty() == true)
+		  ParentTag = Tag;
+	       else
+		  ParentTag.append("::").append(Tag);
+	       Tag.clear();
+	    }
+
+	    // Generate the item name
+	    string Item;
+	    if (ParentTag.empty() == true)
+	       Item = Tag;
+	    else
+	    {
+	       if (TermChar != '{' || Tag.empty() == false)
+		  Item = ParentTag + "::" + Tag;
+	       else
+		  Item = ParentTag;
+	    }
+
+	    // Specials
+	    if (Tag.length() >= 1 && Tag[0] == '#')
+	    {
+	       if (ParentTag.empty() == false)
+		  return _error->Error(_("Syntax error %s:%u: Directives can only be done at the top level"),FName.c_str(),CurLine);
+	       Tag.erase(Tag.begin());
+	       if (Tag == "clear")
+		  Conf.Clear(Word);
+	       else if (Tag == "include")
+	       {
+		  if (Depth > 10)
+		     return _error->Error(_("Syntax error %s:%u: Too many nested includes"),FName.c_str(),CurLine);
+		  if (Word.length() > 2 && Word.end()[-1] == '/')
+		  {
+		     if (ReadConfigDir(Conf,Word,AsSectional,Depth+1) == false)
+			return _error->Error(_("Syntax error %s:%u: Included from here"),FName.c_str(),CurLine);
+		  }
+		  else
+		  {
+		     if (ReadConfigFile(Conf,Word,AsSectional,Depth+1) == false)
+			return _error->Error(_("Syntax error %s:%u: Included from here"),FName.c_str(),CurLine);
+		  }
+	       }
+	       else if (Tag == "x-apt-configure-index")
+	       {
+		  if (LoadConfigurationIndex(Word) == false)
+		     return _error->Warning("Loading the configure index %s in file %s:%u failed!", Word.c_str(), FName.c_str(), CurLine);
+	       }
+	       else
+		  return _error->Error(_("Syntax error %s:%u: Unsupported directive '%s'"),FName.c_str(),CurLine,Tag.c_str());
+	    }
+	    else if (Tag.empty() == true && NoWord == false && Word == "#clear")
+	       return _error->Error(_("Syntax error %s:%u: clear directive requires an option tree as argument"),FName.c_str(),CurLine);
+	    else
+	    {
+	       // Set the item in the configuration class
+	       if (NoWord == false)
+		  Conf.Set(Item,Word);
+	    }
+
+	    // Empty the buffer
+	    LineBuffer.clear();
+
+	    // Move up a tag, but only if there is no bit to parse
+	    if (TermChar == '}')
+	       leaveCurrentScope(Stack, ParentTag);
+	 }
+      }
+
+      // Store the remaining text, if any, in the current line buffer.
+
+      // NB: could change this to use string-based operations; I'm
+      // using strstrip now to ensure backwards compatibility.
+      //   -- dburrows 2008-04-01
+      {
+	char *Buffer = new char[End - Start + 1];
+	try
+	  {
+	    std::copy(Start, End, Buffer);
+	    Buffer[End - Start] = '\0';
+
+	    const char *Stripd = _strstrip(Buffer);
+	    if (*Stripd != 0 && LineBuffer.empty() == false)
+	      LineBuffer += " ";
+	    LineBuffer += Stripd;
+	  }
+	catch(...)
+	  {
+	    delete[] Buffer;
+	    throw;
+	  }
+	delete[] Buffer;
+      }
+   }
+
+   if (LineBuffer.empty() == false)
+      return _error->Error(_("Syntax error %s:%u: Extra junk at end of file"),FName.c_str(),CurLine);
+   return true;
+}
+									/*}}}*/
+// ReadConfigDir - Read a directory of config files			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool ReadConfigDir(Configuration &Conf,const string &Dir,
+		   bool const &AsSectional, unsigned const &Depth)
+{
+   _error->PushToStack();
+   auto const files = GetListOfFilesInDir(Dir, "conf", true, true);
+   auto const successfulList = not _error->PendingError();
+   _error->MergeWithStack();
+   return std::accumulate(files.cbegin(), files.cend(), true, [&](bool good, auto const &file) {
+      return ReadConfigFile(Conf, file, AsSectional, Depth) && good;
+   }) && successfulList;
+}
+									/*}}}*/
+// MatchAgainstConfig Constructor					/*{{{*/
+Configuration::MatchAgainstConfig::MatchAgainstConfig(char const * Config)
+{
+   std::vector<std::string> const strings = _config->FindVector(Config);
+   for (std::vector<std::string>::const_iterator s = strings.begin();
+	s != strings.end(); ++s)
+   {
+      regex_t *p = new regex_t;
+      if (regcomp(p, s->c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB) == 0)
+	 patterns.push_back(p);
+      else
+      {
+	 regfree(p);
+	 delete p;
+	 _error->Warning("Invalid regular expression '%s' in configuration "
+                         "option '%s' will be ignored.",
+                         s->c_str(), Config);
+	 continue;
+      }
+   }
+   if (strings.empty() == true)
+      patterns.push_back(NULL);
+}
+									/*}}}*/
+// MatchAgainstConfig Destructor					/*{{{*/
+Configuration::MatchAgainstConfig::~MatchAgainstConfig()
+{
+   clearPatterns();
+}
+void Configuration::MatchAgainstConfig::clearPatterns()
+{
+   for(std::vector<regex_t *>::const_iterator p = patterns.begin();
+	p != patterns.end(); ++p)
+   {
+      if (*p == NULL) continue;
+      regfree(*p);
+      delete *p;
+   }
+   patterns.clear();
+}
+									/*}}}*/
+// MatchAgainstConfig::Match - returns true if a pattern matches	/*{{{*/
+bool Configuration::MatchAgainstConfig::Match(char const * str) const
+{
+   for(std::vector<regex_t *>::const_iterator p = patterns.begin();
+	p != patterns.end(); ++p)
+      if (*p != NULL && regexec(*p, str, 0, 0, 0) == 0)
+	 return true;
+
+   return false;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/configuration.h b/apt-pkg/contrib/configuration.h
new file mode 100644
index 0000000..6ebf28d
--- /dev/null
+++ b/apt-pkg/contrib/configuration.h
@@ -0,0 +1,152 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Configuration Class
+   
+   This class provides a configuration file and command line parser
+   for a tree-oriented configuration environment. All runtime configuration
+   is stored in here.
+   
+   Each configuration name is given as a fully scoped string such as
+     Foo::Bar
+   And has associated with it a text string. The Configuration class only
+   provides storage and lookup for this tree, other classes provide
+   configuration file formats (and parsers/emitters if needed).
+
+   Most things can get by quite happily with,
+     cout << _config->Find("Foo::Bar") << endl;
+
+   A special extension, support for ordered lists is provided by using the
+   special syntax, "block::list::" the trailing :: designates the 
+   item as a list. To access the list you must use the tree function on
+   "block::list".
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_CONFIGURATION_H
+#define PKGLIB_CONFIGURATION_H
+
+#include <regex.h>
+
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include <apt-pkg/macros.h>
+
+
+class APT_PUBLIC Configuration
+{
+   public:
+   
+   struct Item
+   {
+      std::string Value;
+      std::string Tag;
+      Item *Parent;
+      Item *Child;
+      Item *Next;
+      
+      std::string FullTag(const Item *Stop = 0) const;
+      
+      Item() : Parent(0), Child(0), Next(0) {};
+   };
+   
+   private:
+   
+   Item *Root;
+   bool ToFree;
+
+   Item *Lookup(Item *Head,const char *S,unsigned long const &Len,bool const &Create);
+   Item *Lookup(const char *Name,const bool &Create);
+   inline const Item *Lookup(const char *Name) const
+   {
+      return const_cast<Configuration *>(this)->Lookup(Name,false);
+   }  
+   
+   public:
+
+   std::string Find(const char *Name,const char *Default = 0) const;
+   std::string Find(std::string const &Name,const char *Default = 0) const {return Find(Name.c_str(),Default);};
+   std::string Find(std::string const &Name, std::string const &Default) const {return Find(Name.c_str(),Default.c_str());};
+   std::string FindFile(const char *Name,const char *Default = 0) const;
+   std::string FindDir(const char *Name,const char *Default = 0) const;
+   /** return a list of child options
+    *
+    * Options like Acquire::Languages are handled as lists which
+    * can be overridden and have a default. For the later two a comma
+    * separated list of values is supported.
+    *
+    * \param Name of the parent node
+    * \param Default list of values separated by commas */
+   std::vector<std::string> FindVector(const char *Name, std::string const &Default = "", bool const Keys = false) const;
+   std::vector<std::string> FindVector(std::string const &Name, std::string const &Default = "", bool const Keys = false) const { return FindVector(Name.c_str(), Default, Keys); };
+
+   int FindI(const char *Name,int const &Default = 0) const;
+   int FindI(std::string const &Name,int const &Default = 0) const {return FindI(Name.c_str(),Default);};
+   bool FindB(const char *Name,bool const &Default = false) const;
+   bool FindB(std::string const &Name,bool const &Default = false) const {return FindB(Name.c_str(),Default);};
+   std::string FindAny(const char *Name,const char *Default = 0) const;
+	      
+   inline void Set(const std::string &Name,const std::string &Value) {Set(Name.c_str(),Value);};
+   void CndSet(const char *Name,const std::string &Value);
+   void CndSet(const char *Name,const int Value);
+   void Set(const char *Name,const std::string &Value);
+   void Set(const char *Name,const int &Value);
+   
+   inline bool Exists(const std::string &Name) const {return Exists(Name.c_str());};
+   bool Exists(const char *Name) const;
+   bool ExistsAny(const char *Name) const;
+
+   void MoveSubTree(char const * const OldRoot, char const * const NewRoot);
+
+   // clear a whole tree
+   void Clear(const std::string &Name);
+   void Clear();
+
+   // remove a certain value from a list (e.g. the list of "APT::Keep-Fds")
+   void Clear(std::string const &List, std::string const &Value);
+   void Clear(std::string const &List, int const &Value);
+
+   inline const Item *Tree(const char *Name) const {return Lookup(Name);};
+
+   inline void Dump() { Dump(std::clog); };
+   void Dump(std::ostream& str);
+   void Dump(std::ostream& str, char const * const root,
+	     char const * const format, bool const emptyValue);
+
+   explicit Configuration(const Item *Root);
+   Configuration();
+   ~Configuration();
+
+   /** \brief match a string against a configurable list of patterns */
+   class MatchAgainstConfig
+   {
+     std::vector<regex_t *> patterns;
+     APT_HIDDEN void clearPatterns();
+
+   public:
+     explicit MatchAgainstConfig(char const * Config);
+     virtual ~MatchAgainstConfig();
+
+     /** \brief Returns \b true for a string matching one of the patterns */
+     bool Match(char const * str) const;
+     bool Match(std::string const &str) const { return Match(str.c_str()); };
+
+     /** \brief returns if the matcher setup was successful */
+     bool wasConstructedSuccessfully() const { return patterns.empty() == false; }
+   };
+};
+
+APT_PUBLIC extern Configuration *_config;
+
+APT_PUBLIC bool ReadConfigFile(Configuration &Conf,const std::string &FName,
+		    bool const &AsSectional = false,
+		    unsigned const &Depth = 0);
+
+APT_PUBLIC bool ReadConfigDir(Configuration &Conf,const std::string &Dir,
+		   bool const &AsSectional = false,
+		   unsigned const &Depth = 0);
+
+#endif
diff --git a/apt-pkg/contrib/error.cc b/apt-pkg/contrib/error.cc
new file mode 100644
index 0000000..dd28af1
--- /dev/null
+++ b/apt-pkg/contrib/error.cc
@@ -0,0 +1,336 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   Global Error Class - Global error mechanism
+
+   We use a simple STL vector to store each error record. A PendingFlag
+   is kept which indicates when the vector contains a Sever error.
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+#include <list>
+#include <string>
+#include <errno.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+									/*}}}*/
+
+// Global Error Object							/*{{{*/
+GlobalError *_GetErrorObj()
+{
+   static thread_local GlobalError Obj;
+   return &Obj;
+}
+									/*}}}*/
+// GlobalError::GlobalError - Constructor				/*{{{*/
+GlobalError::GlobalError() : PendingFlag(false) {}
+									/*}}}*/
+// GlobalError::FatalE, Errno, WarningE, NoticeE and DebugE - Add to the list/*{{{*/
+#define GEMessage(NAME, TYPE) \
+bool GlobalError::NAME (const char *Function, const char *Description,...) { \
+	va_list args; \
+	size_t msgSize = 400; \
+	int const errsv = errno; \
+	bool retry; \
+	do { \
+		va_start(args,Description); \
+		retry = InsertErrno(TYPE, Function, Description, args, errsv, msgSize); \
+		va_end(args); \
+	} while (retry); \
+	return false; \
+}
+GEMessage(FatalE, FATAL)
+GEMessage(Errno, ERROR)
+GEMessage(WarningE, WARNING)
+GEMessage(NoticeE, NOTICE)
+GEMessage(DebugE, DEBUG)
+#undef GEMessage
+									/*}}}*/
+// GlobalError::InsertErrno - Get part of the errortype string from errno/*{{{*/
+bool GlobalError::InsertErrno(MsgType const &type, const char *Function,
+				const char *Description,...) {
+	va_list args;
+	size_t msgSize = 400;
+	int const errsv = errno;
+	bool retry;
+	do {
+		va_start(args,Description);
+		retry = InsertErrno(type, Function, Description, args, errsv, msgSize);
+		va_end(args);
+	} while (retry);
+	return false;
+}
+									/*}}}*/
+// GlobalError::InsertErrno - formats an error message with the errno	/*{{{*/
+bool GlobalError::InsertErrno(MsgType type, const char* Function,
+			      const char* Description, va_list &args,
+			      int const errsv, size_t &msgSize) {
+	char* S = (char*) malloc(msgSize);
+	int const n = snprintf(S, msgSize, "%s - %s (%i: %s)", Description,
+			       Function, errsv, strerror(errsv));
+	if (n > -1 && ((unsigned int) n) < msgSize);
+	else {
+		if (n > -1)
+			msgSize = n + 1;
+		else
+			msgSize *= 2;
+		free(S);
+		return true;
+	}
+
+	bool const geins = Insert(type, S, args, msgSize);
+	free(S);
+	return geins;
+}
+									/*}}}*/
+// GlobalError::Fatal, Error, Warning, Notice and Debug - Add to the list/*{{{*/
+#define GEMessage(NAME, TYPE) \
+bool GlobalError::NAME (const char *Description,...) { \
+	va_list args; \
+	size_t msgSize = 400; \
+	bool retry; \
+	do { \
+		va_start(args,Description); \
+		retry = Insert(TYPE, Description, args, msgSize); \
+		va_end(args); \
+	} while (retry); \
+	return false; \
+}
+GEMessage(Fatal, FATAL)
+GEMessage(Error, ERROR)
+GEMessage(Warning, WARNING)
+GEMessage(Notice, NOTICE)
+GEMessage(Debug, DEBUG)
+#undef GEMessage
+									/*}}}*/
+// GlobalError::Insert - Add a errotype message to the list		/*{{{*/
+bool GlobalError::Insert(MsgType const &type, const char *Description,...)
+{
+	va_list args;
+	size_t msgSize = 400;
+	bool retry;
+	do {
+		va_start(args,Description);
+		retry = Insert(type, Description, args, msgSize);
+		va_end(args);
+	} while (retry);
+	return false;
+}
+									/*}}}*/
+// GlobalError::Insert - Insert a new item at the end			/*{{{*/
+bool GlobalError::Insert(MsgType type, const char* Description,
+			 va_list &args, size_t &msgSize) {
+	char* S = (char*) malloc(msgSize);
+	int const n = vsnprintf(S, msgSize, Description, args);
+	if (n > -1 && ((unsigned int) n) < msgSize);
+	else {
+		if (n > -1)
+			msgSize = n + 1;
+		else
+			msgSize *= 2;
+ 		free(S);
+		return true;
+	}
+
+	Item const m(S, type);
+	Messages.push_back(m);
+
+	if (type == ERROR || type == FATAL)
+		PendingFlag = true;
+
+	if (type == FATAL || type == DEBUG)
+		std::clog << m << std::endl;
+
+	free(S);
+	return false;
+}
+									/*}}}*/
+// GlobalError::PopMessage - Pulls a single message out			/*{{{*/
+bool GlobalError::PopMessage(std::string &Text) {
+	if (Messages.empty() == true)
+		return false;
+
+	Item const msg = Messages.front();
+	Messages.pop_front();
+
+	bool const Ret = (msg.Type == ERROR || msg.Type == FATAL);
+	Text = msg.Text;
+	if (PendingFlag == false || Ret == false)
+		return Ret;
+
+	// check if another error message is pending
+	for (std::list<Item>::const_iterator m = Messages.begin();
+	     m != Messages.end(); ++m)
+		if (m->Type == ERROR || m->Type == FATAL)
+			return Ret;
+
+	PendingFlag = false;
+	return Ret;
+}
+									/*}}}*/
+// GlobalError::DumpErrors - Dump all of the errors/warns to cerr	/*{{{*/
+void GlobalError::DumpErrors(std::ostream &out, MsgType const &threshold,
+			     bool const &mergeStack) {
+	if (mergeStack == true)
+		for (std::list<MsgStack>::const_reverse_iterator s = Stacks.rbegin();
+		     s != Stacks.rend(); ++s)
+			std::copy(s->Messages.begin(), s->Messages.end(), std::front_inserter(Messages));
+
+	std::for_each(Messages.begin(), Messages.end(), [&threshold, &out](Item const &m) {
+		if (m.Type >= threshold)
+			out << m << std::endl;
+	});
+
+	Discard();
+}
+									/*}}}*/
+// GlobalError::Discard - Discard					/*{{{*/
+void GlobalError::Discard() {
+	Messages.clear();
+	PendingFlag = false;
+}
+									/*}}}*/
+// GlobalError::empty - does our error list include anything?		/*{{{*/
+bool GlobalError::empty(MsgType const &threshold) const {
+	if (PendingFlag == true)
+		return false;
+
+	if (Messages.empty() == true)
+		return true;
+
+	return std::find_if(Messages.begin(), Messages.end(), [&threshold](Item const &m) {
+		return m.Type >= threshold;
+	}) == Messages.end();
+}
+									/*}}}*/
+// GlobalError::PushToStack						/*{{{*/
+void GlobalError::PushToStack() {
+	Stacks.emplace_back(Messages, PendingFlag);
+	Discard();
+}
+									/*}}}*/
+// GlobalError::RevertToStack						/*{{{*/
+void GlobalError::RevertToStack() {
+	Discard();
+	MsgStack pack = Stacks.back();
+	Messages = pack.Messages;
+	PendingFlag = pack.PendingFlag;
+	Stacks.pop_back();
+}
+									/*}}}*/
+// GlobalError::MergeWithStack						/*{{{*/
+void GlobalError::MergeWithStack() {
+	MsgStack pack = Stacks.back();
+	Messages.splice(Messages.begin(), pack.Messages);
+	PendingFlag = PendingFlag || pack.PendingFlag;
+	Stacks.pop_back();
+}
+									/*}}}*/
+
+// GlobalError::Item::operator<<						/*{{{*/
+APT_HIDDEN std::ostream &operator<<(std::ostream &out, GlobalError::Item i)
+{
+   static constexpr auto COLOR_RESET = "\033[0m";
+   static constexpr auto COLOR_NOTICE = "\033[33m";  // normal yellow
+   static constexpr auto COLOR_WARN = "\033[1;33m";  // bold yellow
+   static constexpr auto COLOR_ERROR = "\033[1;31m"; // bold red
+
+   bool use_color = _config->FindB("APT::Color", false);
+
+   if (use_color)
+   {
+      switch (i.Type)
+      {
+      case GlobalError::FATAL:
+      case GlobalError::ERROR:
+	 out << COLOR_ERROR;
+	 break;
+      case GlobalError::WARNING:
+	 out << COLOR_WARN;
+	 break;
+      case GlobalError::NOTICE:
+	 out << COLOR_NOTICE;
+	 break;
+      default:
+	 break;
+      }
+   }
+
+   switch (i.Type)
+   {
+   case GlobalError::FATAL:
+   case GlobalError::ERROR:
+      out << 'E';
+      break;
+   case GlobalError::WARNING:
+      out << 'W';
+      break;
+   case GlobalError::NOTICE:
+      out << 'N';
+      break;
+   case GlobalError::DEBUG:
+      out << 'D';
+      break;
+   }
+   out << ": ";
+
+   if (use_color)
+   {
+      switch (i.Type)
+      {
+      case GlobalError::FATAL:
+      case GlobalError::ERROR:
+      case GlobalError::WARNING:
+      case GlobalError::NOTICE:
+	 out << COLOR_RESET;
+	 break;
+      default:
+	 break;
+      }
+   }
+
+   std::string::size_type line_start = 0;
+   std::string::size_type line_end;
+   while ((line_end = i.Text.find_first_of("\n\r", line_start)) != std::string::npos)
+   {
+      if (line_start != 0)
+	 out << std::endl
+	     << "   ";
+      out << i.Text.substr(line_start, line_end - line_start);
+      line_start = i.Text.find_first_not_of("\n\r", line_end + 1);
+      if (line_start == std::string::npos)
+	 break;
+   }
+   if (line_start == 0)
+      out << i.Text;
+   else if (line_start != std::string::npos)
+      out << std::endl
+	  << "   " << i.Text.substr(line_start);
+
+   if (use_color)
+      out << COLOR_RESET;
+
+   return out;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/error.h b/apt-pkg/contrib/error.h
new file mode 100644
index 0000000..dd50b9c
--- /dev/null
+++ b/apt-pkg/contrib/error.h
@@ -0,0 +1,349 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Global Error Class - Global error mechanism
+
+   This class has a single global instance. When a function needs to 
+   generate an error condition, such as a read error, it calls a member
+   in this class to add the error to a stack of errors. 
+   
+   By using a stack the problem with a scheme like errno is removed and
+   it allows a very detailed account of what went wrong to be transmitted
+   to the UI for display. (Errno has problems because each function sets
+   errno to 0 if it didn't have an error thus eraseing erno in the process
+   of cleanup)
+   
+   Several predefined error generators are provided to handle common 
+   things like errno. The general idea is that all methods return a bool.
+   If the bool is true then things are OK, if it is false then things 
+   should start being undone and the stack should unwind under program
+   control.
+   
+   A Warning should not force the return of false. Things did not fail, but
+   they might have had unexpected problems. Errors are stored in a FIFO
+   so Pop will return the first item..
+   
+   I have some thoughts about extending this into a more general UI<-> 
+   Engine interface, ie allowing the Engine to say 'The disk is full' in 
+   a dialog that says 'Panic' and 'Retry'.. The error generator functions
+   like errno, Warning and Error return false always so this is normal:
+     if (open(..))
+        return _error->Errno(..);
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_ERROR_H
+#define PKGLIB_ERROR_H
+
+#include <apt-pkg/macros.h>
+
+#include <iostream>
+#include <list>
+#include <string>
+
+#include <stdarg.h>
+#include <stddef.h>
+
+class APT_PUBLIC GlobalError						/*{{{*/
+{
+public:									/*{{{*/
+	/** \brief a message can have one of following severity */
+	enum MsgType {
+		/** \brief Message will be printed instantly as it is likely that
+			this error will lead to a complete crash */
+		FATAL = 40,
+		/** \brief An error does hinder the correct execution and should be corrected */
+		ERROR = 30,
+		/** \brief indicates problem that can lead to errors later on */
+		WARNING = 20,
+		/** \brief deprecation warnings, old fallback behavior, … */
+		NOTICE = 10,
+		/** \brief for developers only in areas it is hard to print something directly */
+		DEBUG = 0
+	};
+
+	/** \brief add a fatal error message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool FatalE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add an Error message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool Errno(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a warning message with errno to the list
+	 *
+	 *  A warning should be considered less severe than an error and
+	 *  may be ignored by the client.
+	 *
+	 *  \param Function Name of the function generates the warning.
+	 *  \param Description Format string for the warning message.
+	 *
+	 *  \return \b false
+	 */
+	bool WarningE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a notice message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool NoticeE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief add a debug message with errno to the list
+	 *
+	 *  \param Function name of the function generating the error
+	 *  \param Description format string for the error message
+	 *
+	 *  \return \b false
+	 */
+	bool DebugE(const char *Function,const char *Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief adds an errno message with the given type
+	 *
+	 * \param type of the error message
+	 * \param Function which failed
+	 * \param Description of the error
+	 */
+	bool InsertErrno(MsgType const &type, const char* Function,
+			 const char* Description,...) APT_PRINTF(4) APT_COLD;
+
+	/** \brief adds an errno message with the given type
+	 *
+	 * args needs to be initialized with va_start and terminated
+	 * with va_end by the caller. msgSize is also an out-parameter
+	 * in case the msgSize was not enough to store the complete message.
+	 *
+	 * \param type of the error message
+	 * \param Function which failed
+	 * \param Description is the format string for args
+	 * \param args list from a printf-like function
+	 * \param errsv is the errno the error is for
+	 * \param msgSize is the size of the char[] used to store message
+	 * \return true if the message was added, false if not - the caller
+	 * should call this method again in that case
+	 */
+	bool InsertErrno(MsgType type, const char* Function,
+			 const char* Description, va_list &args,
+			 int const errsv, size_t &msgSize) APT_COLD;
+
+	/** \brief add an fatal error message to the list
+	 *
+	 *  Most of the stuff we consider as "error" is also "fatal" for
+	 *  the user as the application will not have the expected result,
+	 *  but a fatal message here means that it gets printed directly
+	 *  to stderr in addition to adding it to the list as the error
+	 *  leads sometimes to crashes and a maybe duplicated message
+	 *  is better than "Segfault" as the only displayed text
+	 *
+	 *  \param Description Format string for the fatal error message.
+	 *
+	 *  \return \b false
+	 */
+	bool Fatal(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add an Error message to the list
+	 *
+	 *  \param Description Format string for the error message.
+	 *
+	 *  \return \b false
+	 */
+	bool Error(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a warning message to the list
+	 *
+	 *  A warning should be considered less severe than an error and
+	 *  may be ignored by the client.
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Warning(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a notice message to the list
+	 *
+	 *  A notice should be considered less severe than an error or a
+	 *  warning and can be ignored by the client without further problems
+	 *  for some times, but he should consider fixing the problem.
+	 *  This error type can be used for e.g. deprecation warnings of options.
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Notice(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief add a debug message to the list
+	 *
+	 *  \param Description Format string for the message
+	 *
+	 *  \return \b false
+	 */
+	bool Debug(const char *Description,...) APT_PRINTF(2) APT_COLD;
+
+	/** \brief adds an error message with the given type
+	 *
+	 * \param type of the error message
+	 * \param Description of the error
+	 */
+	bool Insert(MsgType const &type, const char* Description,...) APT_PRINTF(3) APT_COLD;
+
+	/** \brief adds an error message with the given type
+	 *
+	 * args needs to be initialized with va_start and terminated
+	 * with va_end by the caller. msgSize is also an out-parameter
+	 * in case the msgSize was not enough to store the complete message.
+	 *
+	 * \param type of the error message
+	 * \param Description is the format string for args
+	 * \param args list from a printf-like function
+	 * \param msgSize is the size of the char[] used to store message
+	 * \return true if the message was added, false if not - the caller
+	 * should call this method again in that case
+	 */
+	bool Insert(MsgType type, const char* Description,
+			 va_list &args, size_t &msgSize) APT_COLD;
+
+	/** \brief is an error in the list?
+	 *
+	 *  \return \b true if an error is included in the list, \b false otherwise
+	 */
+	inline bool PendingError() const APT_PURE {return PendingFlag;};
+
+	/** \brief is the list empty?
+	 *
+	 *  Can be used to check if the current stack level doesn't include
+	 *  anything equal or more severe than a given threshold, defaulting
+	 *  to warning level for historic reasons.
+	 *
+	 *  \param threshold minimum level considered
+	 *
+	 *  \return \b true if the list is empty, \b false otherwise
+	 */
+	bool empty(MsgType const &threshold = WARNING) const APT_PURE;
+
+	/** \brief returns and removes the first (or last) message in the list
+	 *
+	 *  \param[out] Text message of the first/last item
+	 *
+	 *  \return \b true if the message was an error, \b false otherwise
+	 */
+	bool PopMessage(std::string &Text);
+
+	/** \brief clears the list of messages */
+	void Discard();
+
+	/** \brief outputs the list of messages to the given stream
+	 *
+	 *  Note that all messages are discarded, even undisplayed ones.
+	 *
+	 *  \param[out] out output stream to write the messages in
+	 *  \param threshold minimum level considered
+	 *  \param mergeStack if true recursively dumps the entire stack
+	 */
+	void DumpErrors(std::ostream &out, MsgType const &threshold = WARNING,
+			bool const &mergeStack = true);
+
+	/** \brief dumps the list of messages to std::cerr
+	 *
+	 *  Note that all messages are discarded, also the notices
+	 *  displayed or not.
+	 *
+	 *  \param threshold minimum level printed
+	 */
+	void inline DumpErrors(MsgType const &threshold) {
+		DumpErrors(std::cerr, threshold);
+	}
+
+        // mvo: we do this instead of using a default parameter in the
+        //      previous declaration to avoid a (subtle) API break for
+        //      e.g. sigc++ and mem_fun0
+	/** \brief dumps the messages of type WARNING or higher to std::cerr
+	 *
+	 *  Note that all messages are discarded, displayed or not.
+	 *
+	 */
+	void inline DumpErrors() {
+                DumpErrors(WARNING);
+	}
+
+	/** \brief put the current Messages into the stack
+	 *
+	 *  All "old" messages will be pushed into a stack to
+	 *  them later back, but for now the Message query will be
+	 *  empty and performs as no messages were present before.
+	 *
+	 * The stack can be as deep as you want - all stack operations
+	 * will only operate on the last element in the stack.
+	 */
+	void PushToStack();
+
+	/** \brief throw away all current messages */
+	void RevertToStack();
+
+	/** \brief merge current and stack together */
+	void MergeWithStack();
+
+	/** \brief return the deep of the stack */
+	size_t StackCount() const APT_PURE {
+		return Stacks.size();
+	}
+
+	GlobalError();
+									/*}}}*/
+private:								/*{{{*/
+	struct Item {
+		std::string Text;
+		MsgType Type;
+
+		Item(char const *Text, MsgType const &Type) :
+			Text(Text), Type(Type) {};
+
+		APT_HIDDEN friend std::ostream &operator<<(std::ostream &out, Item i);
+	};
+
+	APT_HIDDEN friend std::ostream &operator<<(std::ostream &out, Item i);
+
+	std::list<Item> Messages;
+	bool PendingFlag;
+
+	struct MsgStack {
+		std::list<Item> Messages;
+		bool const PendingFlag;
+
+		MsgStack(std::list<Item> const &Messages, bool const &Pending) :
+			 Messages(Messages), PendingFlag(Pending) {};
+	};
+
+	std::list<MsgStack> Stacks;
+									/*}}}*/
+};
+									/*}}}*/
+
+// The 'extra-ansi' syntax is used to help with collisions. 
+APT_PUBLIC GlobalError *_GetErrorObj();
+static struct {
+	inline GlobalError* operator ->() { return _GetErrorObj(); }
+} _error APT_UNUSED;
+
+#endif
diff --git a/apt-pkg/contrib/extracttar.cc b/apt-pkg/contrib/extracttar.cc
new file mode 100644
index 0000000..dc24375
--- /dev/null
+++ b/apt-pkg/contrib/extracttar.cc
@@ -0,0 +1,325 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Extract a Tar - Tar Extractor
+
+   Some performance measurements showed that zlib performed quite poorly
+   in comparison to a forked gzip process. This tar extractor makes use
+   of the fact that dup'd file descriptors have the same seek pointer
+   and that gzip will not read past the end of a compressed stream, 
+   even if there is more data. We use the dup property to track extraction
+   progress and the gzip feature to just feed gzip a fd in the middle
+   of an AR file. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/extracttar.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <fcntl.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+    
+// The on disk header for a tar file.
+struct ExtractTar::TarHeader
+{
+   char Name[100];
+   char Mode[8];
+   char UserID[8];
+   char GroupID[8];
+   char Size[12];
+   char MTime[12];
+   char Checksum[8];
+   char LinkFlag;
+   char LinkName[100];
+   char MagicNumber[8];
+   char UserName[32];
+   char GroupName[32];
+   char Major[8];
+   char Minor[8];      
+};
+
+// We need to read long names (names and link targets) into memory, so let's
+// have a limit (shamelessly stolen from libarchive) to avoid people OOMing
+// us with large streams.
+static const unsigned long long APT_LONGNAME_LIMIT = 1048576llu;
+
+// A file size limit that we allow extracting. Currently, that's 128 GB.
+// We also should leave some wiggle room for code adding files to it, and
+// possibly conversion for signed, so this should not be larger than like 2**62.
+static const unsigned long long APT_FILESIZE_LIMIT = 1llu << 37;
+
+// ExtractTar::ExtractTar - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::ExtractTar(FileFd &Fd,unsigned long long Max,string DecompressionProgram)
+	: File(Fd), MaxInSize(Max), DecompressProg(DecompressionProgram)
+{
+   GZPid = -1;
+   Eof = false;
+}
+									/*}}}*/
+// ExtractTar::ExtractTar - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::~ExtractTar()
+{
+   // Error close
+   Done();
+}
+									/*}}}*/
+// ExtractTar::Done - Reap the gzip sub process				/*{{{*/
+bool ExtractTar::Done()
+{
+   return InFd.Close();
+}
+									/*}}}*/
+// ExtractTar::StartGzip - Startup gzip					/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a gzip sub process that has its input as the file itself.
+   If this tar file is embedded into something like an ar file then 
+   gzip will efficiently ignore the extra bits. */
+bool ExtractTar::StartGzip()
+{
+   if (DecompressProg.empty())
+   {
+      InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, FileFd::None, false);
+      return true;
+   }
+
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   for (; compressor != compressors.end(); ++compressor) {
+      if (compressor->Name == DecompressProg) {
+	 return InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, *compressor, false);
+      }
+   }
+
+   return _error->Error(_("Cannot find a configured compressor for '%s'"),
+			DecompressProg.c_str());
+
+}
+									/*}}}*/
+// ExtractTar::Go - Perform extraction					/*{{{*/
+// ---------------------------------------------------------------------
+/* This reads each 512 byte block from the archive and extracts the header
+   information into the Item structure. Then it resolves the UID/GID and
+   invokes the correct processing function. */
+bool ExtractTar::Go(pkgDirStream &Stream)
+{   
+   if (StartGzip() == false)
+      return false;
+   
+   // Loop over all blocks
+   string LastLongLink, ItemLink;
+   string LastLongName, ItemName;
+   while (1)
+   {
+      bool BadRecord = false;      
+      unsigned char Block[512];      
+      if (InFd.Read(Block,sizeof(Block),true) == false)
+	 return false;
+      
+      if (InFd.Eof() == true)
+	 break;
+
+      // Get the checksum
+      TarHeader *Tar = (TarHeader *)Block;
+      unsigned long CheckSum;
+      if (StrToNum(Tar->Checksum,CheckSum,sizeof(Tar->Checksum),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+      
+      /* Compute the checksum field. The actual checksum is blanked out
+         with spaces so it is not included in the computation */
+      unsigned long NewSum = 0;
+      memset(Tar->Checksum,' ',sizeof(Tar->Checksum));
+      for (int I = 0; I != sizeof(Block); I++)
+	 NewSum += Block[I];
+      
+      /* Check for a block of nulls - in this case we kill gzip, GNU tar
+       	 does this.. */
+      if (NewSum == ' '*sizeof(Tar->Checksum))
+	 return Done();
+      
+      if (NewSum != CheckSum)
+	 return _error->Error(_("Tar checksum failed, archive corrupted"));
+   
+      // Decode all of the fields
+      pkgDirStream::Item Itm;
+      if (StrToNum(Tar->Mode,Itm.Mode,sizeof(Tar->Mode),8) == false ||
+          (Base256ToNum(Tar->UserID,Itm.UID,8) == false &&
+	     StrToNum(Tar->UserID,Itm.UID,sizeof(Tar->UserID),8) == false) ||
+          (Base256ToNum(Tar->GroupID,Itm.GID,8) == false &&
+	     StrToNum(Tar->GroupID,Itm.GID,sizeof(Tar->GroupID),8) == false) ||
+          (Base256ToNum(Tar->Size,Itm.Size,12) == false &&
+	     StrToNum(Tar->Size,Itm.Size,sizeof(Tar->Size),8) == false) ||
+          (Base256ToNum(Tar->MTime,Itm.MTime,12) == false &&
+	     StrToNum(Tar->MTime,Itm.MTime,sizeof(Tar->MTime),8) == false) ||
+	  StrToNum(Tar->Major,Itm.Major,sizeof(Tar->Major),8) == false ||
+	  StrToNum(Tar->Minor,Itm.Minor,sizeof(Tar->Minor),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+
+      // Security check. Prevents overflows below the code when rounding up in skip/copy code,
+      // and provides modest protection against decompression bombs.
+      if (Itm.Size > APT_FILESIZE_LIMIT)
+	 return _error->Error("Tar member too large: %llu > %llu bytes", Itm.Size, APT_FILESIZE_LIMIT);
+
+      // Grab the filename and link target: use last long name if one was
+      // set, otherwise use the header value as-is, but remember that it may
+      // fill the entire 100-byte block and needs to be zero-terminated.
+      // See Debian Bug #689582.
+      if (LastLongName.empty() == false)
+	 Itm.Name = (char *)LastLongName.c_str();
+      else
+	 Itm.Name = (char *)ItemName.assign(Tar->Name, sizeof(Tar->Name)).c_str();
+      if (Itm.Name[0] == '.' && Itm.Name[1] == '/' && Itm.Name[2] != 0)
+	 Itm.Name += 2;
+
+      if (LastLongLink.empty() == false)
+	 Itm.LinkTarget = (char *)LastLongLink.c_str();
+      else
+	 Itm.LinkTarget = (char *)ItemLink.assign(Tar->LinkName, sizeof(Tar->LinkName)).c_str();
+
+      // Convert the type over
+      switch (Tar->LinkFlag)
+      {
+	 case NormalFile0:
+	 case NormalFile:
+	 Itm.Type = pkgDirStream::Item::File;
+	 break;
+	 
+	 case HardLink:
+	 Itm.Type = pkgDirStream::Item::HardLink;
+	 break;
+	 
+	 case SymbolicLink:
+	 Itm.Type = pkgDirStream::Item::SymbolicLink;
+	 break;
+	 
+	 case CharacterDevice:
+	 Itm.Type = pkgDirStream::Item::CharDevice;
+	 break;
+	    
+	 case BlockDevice:
+	 Itm.Type = pkgDirStream::Item::BlockDevice;
+	 break;
+	 
+	 case Directory:
+	 Itm.Type = pkgDirStream::Item::Directory;
+	 break;
+	 
+	 case FIFO:
+	 Itm.Type = pkgDirStream::Item::FIFO;
+	 break;
+
+	 case GNU_LongLink:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length <= sizeof(Block))
+	       {
+		  LastLongLink.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongLink.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 case GNU_LongName:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length < sizeof(Block))
+	       {
+		  LastLongName.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongName.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 default:
+	 BadRecord = true;
+	 _error->Warning(_("Unknown TAR header type %u"), (unsigned)Tar->LinkFlag);
+	 break;
+      }
+
+      int Fd = -1;
+      if (not BadRecord && not Stream.DoItem(Itm, Fd))
+	 return false;
+
+      if (Fd == -1 || Fd < -2 || BadRecord)
+      {
+	 if (Itm.Size > 0 && not InFd.Skip(((Itm.Size + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	    return false;
+      }
+      else if (Itm.Size != 0)
+      {
+	 // Copy the file over the FD
+	 auto Size = Itm.Size;
+	 unsigned char Junk[32*1024];
+	 do
+	 {
+	    auto const Read = std::min<unsigned long long>(Size, sizeof(Junk));
+	    if (not InFd.Read(Junk, ((Read + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	       return false;
+
+	    if (Fd > 0)
+	    {
+	       if (not FileFd::Write(Fd, Junk, Read))
+		  return Stream.Fail(Itm, Fd);
+	    }
+	    // An Fd of -2 means to send to a special processing function
+	    else if (Fd == -2)
+	    {
+	       if (not Stream.Process(Itm, Junk, Read, Itm.Size - Size))
+		  return Stream.Fail(Itm, Fd);
+	    }
+
+	    Size -= Read;
+	 } while (Size != 0);
+      }
+
+      // And finish up
+      if (not BadRecord && not Stream.FinishedFile(Itm, Fd))
+	 return false;
+      LastLongName.erase();
+      LastLongLink.erase();
+   }
+
+   return Done();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/extracttar.h b/apt-pkg/contrib/extracttar.h
new file mode 100644
index 0000000..a3c862a
--- /dev/null
+++ b/apt-pkg/contrib/extracttar.h
@@ -0,0 +1,55 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Extract a Tar - Tar Extractor
+   
+   The tar extractor takes an ordinary gzip compressed tar stream from 
+   the given file and explodes it, passing the individual items to the
+   given Directory Stream for processing.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_EXTRACTTAR_H
+#define PKGLIB_EXTRACTTAR_H
+
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+
+#include <string>
+
+
+class pkgDirStream;
+
+class APT_PUBLIC ExtractTar
+{
+   protected:
+   
+   struct TarHeader;
+   
+   // The varios types items can be
+   enum ItemType {NormalFile0 = '\0',NormalFile = '0',HardLink = '1',
+                  SymbolicLink = '2',CharacterDevice = '3',
+                  BlockDevice = '4',Directory = '5',FIFO = '6',
+                  GNU_LongLink = 'K',GNU_LongName = 'L'};
+
+   FileFd &File;
+   unsigned long long MaxInSize;
+   int GZPid;
+   FileFd InFd;
+   bool Eof;
+   std::string DecompressProg;
+   
+   // Fork and reap gzip
+   bool StartGzip();
+   bool Done();
+
+   public:
+
+   bool Go(pkgDirStream &Stream);
+
+   ExtractTar(FileFd &Fd,unsigned long long Max,std::string DecompressionProgram);
+   virtual ~ExtractTar();
+};
+
+#endif
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
new file mode 100644
index 0000000..fad51de
--- /dev/null
+++ b/apt-pkg/contrib/fileutl.cc
@@ -0,0 +1,3483 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   File Utilities
+   
+   CopyFile - Buffered copy of a single file
+   GetLock - dpkg compatible lock file manipulation (fcntl)
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Most of this source is placed in the Public Domain, do with it what 
+   you will
+   It was originally written by Jason Gunthorpe <jgg@debian.org>.
+   FileFd gzip support added by Martin Pitt <martin.pitt@canonical.com>
+   
+   The exception is RunScripts() it is under the GPLv2
+
+   We believe that this reference to GPLv2 was not meant to exclude later
+   versions as that would have changed the overall project license from GPL-2+
+   to GPL-2.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/pkgsystem.h>
+#include <apt-pkg/strutl.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <vector>
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <glob.h>
+#include <grp.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <memory>
+#include <set>
+
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+#endif
+#ifdef HAVE_BZ2
+#include <bzlib.h>
+#endif
+#ifdef HAVE_LZMA
+#include <lzma.h>
+#endif
+#ifdef HAVE_LZ4
+#include <lz4frame.h>
+#endif
+#ifdef HAVE_ZSTD
+#include <zstd.h>
+#endif
+#ifdef HAVE_SYSTEMD
+#include <systemd/sd-bus.h>
+#endif
+#include <endian.h>
+#include <stdint.h>
+
+#if __gnu_linux__
+#include <sys/prctl.h>
+#endif
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// RunScripts - Run a set of scripts from a configuration subtree	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RunScripts(const char *Cnf)
+{
+   Configuration::Item const *Opts = _config->Tree(Cnf);
+   if (Opts == 0 || Opts->Child == 0)
+      return true;
+   Opts = Opts->Child;
+
+   // Fork for running the system calls
+   pid_t Child = ExecFork();
+   
+   // This is the child
+   if (Child == 0)
+   {
+      if (_system != nullptr && _system->IsLocked() == true && (stringcasecmp(Cnf, "dpkg::post-invoke") == 0 || stringcasecmp(Cnf, "dpkg::pre-invoke") == 0))
+	 setenv("DPKG_FRONTEND_LOCKED", "true", 1);
+      if (_config->FindDir("DPkg::Chroot-Directory","/") != "/") 
+      {
+         std::cerr << "Chrooting into " 
+                   << _config->FindDir("DPkg::Chroot-Directory") 
+                   << std::endl;
+         if (chroot(_config->FindDir("DPkg::Chroot-Directory","/").c_str()) != 0)
+            _exit(100);
+      }
+
+      if (chdir("/tmp/") != 0)
+	 _exit(100);
+	 
+      unsigned int Count = 1;
+      for (; Opts != 0; Opts = Opts->Next, Count++)
+      {
+	 if (Opts->Value.empty() == true)
+	    continue;
+
+         if(_config->FindB("Debug::RunScripts", false) == true)
+            std::clog << "Running external script: '"
+                      << Opts->Value << "'" << std::endl;
+
+	 if (system(Opts->Value.c_str()) != 0)
+	    _exit(100+Count);
+      }
+      _exit(0);
+   }      
+
+   // Wait for the child
+   int Status = 0;
+   while (waitpid(Child,&Status,0) != Child)
+   {
+      if (errno == EINTR)
+	 continue;
+      return _error->Errno("waitpid","Couldn't wait for subprocess");
+   }
+
+   // Check for an error code.
+   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
+   {
+      unsigned int Count = WEXITSTATUS(Status);
+      if (Count > 100)
+      {
+	 Count -= 100;
+	 for (; Opts != 0 && Count != 1; Opts = Opts->Next, Count--);
+	 _error->Error("Problem executing scripts %s '%s'",Cnf,Opts->Value.c_str());
+      }
+      
+      return _error->Error("Sub-process returned an error code");
+   }
+   
+   return true;
+}
+									/*}}}*/
+
+// CopyFile - Buffered copy of a file					/*{{{*/
+// ---------------------------------------------------------------------
+/* The caller is expected to set things so that failure causes erasure */
+bool CopyFile(FileFd &From,FileFd &To)
+{
+   if (From.IsOpen() == false || To.IsOpen() == false ||
+	 From.Failed() == true || To.Failed() == true)
+      return false;
+
+   // Buffered copy between fds
+   constexpr size_t BufSize = APT_BUFFER_SIZE;
+   std::unique_ptr<unsigned char[]> Buf(new unsigned char[BufSize]);
+   unsigned long long ToRead = 0;
+   do {
+      if (From.Read(Buf.get(),BufSize, &ToRead) == false ||
+	  To.Write(Buf.get(),ToRead) == false)
+	 return false;
+   } while (ToRead != 0);
+
+   return true;
+}
+									/*}}}*/
+bool RemoveFileAt(char const * const Function, int const dirfd, std::string const &FileName)/*{{{*/
+{
+   if (FileName == "/dev/null")
+      return true;
+   errno = 0;
+   if (unlinkat(dirfd, FileName.c_str(), 0) != 0)
+   {
+      if (errno == ENOENT)
+	 return true;
+
+      return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+bool RemoveFile(char const * const Function, std::string const &FileName)/*{{{*/
+{
+   if (FileName == "/dev/null")
+      return true;
+   errno = 0;
+   if (unlink(FileName.c_str()) != 0)
+   {
+      if (errno == ENOENT)
+	 return true;
+
+      return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// GetLock - Gets a lock file						/*{{{*/
+// ---------------------------------------------------------------------
+/* This will create an empty file of the given name and lock it. Once this
+   is done all other calls to GetLock in any other process will fail with
+   -1. The return result is the fd of the file, the call should call
+   close at some time. */
+
+static std::string GetProcessName(int pid)
+{
+   struct HideError
+   {
+      int err;
+      HideError() : err(errno) { _error->PushToStack(); }
+      ~HideError()
+      {
+	 errno = err;
+	 _error->RevertToStack();
+      }
+   } hideError;
+   std::string path;
+   strprintf(path, "/proc/%d/status", pid);
+   FileFd status(path, FileFd::ReadOnly);
+   std::string line;
+   while (status.ReadLine(line))
+   {
+      if (line.substr(0, 5) == "Name:")
+	 return line.substr(6);
+   }
+   return "";
+}
+int GetLock(string File,bool Errors)
+{
+   // GetLock() is used in aptitude on directories with public-write access
+   // Use O_NOFOLLOW here to prevent symlink traversal attacks
+   int FD = open(File.c_str(),O_RDWR | O_CREAT | O_NOFOLLOW,0640);
+   if (FD < 0)
+   {
+      // Read only .. can't have locking problems there.
+      if (errno == EROFS)
+      {
+	 _error->Warning(_("Not using locking for read only lock file %s"),File.c_str());
+	 return dup(0);       // Need something for the caller to close
+      }
+      
+      if (Errors == true)
+	 _error->Errno("open",_("Could not open lock file %s"),File.c_str());
+
+      // Feh.. We do this to distinguish the lock vs open case..
+      errno = EPERM;
+      return -1;
+   }
+   SetCloseExec(FD,true);
+      
+   // Acquire a write lock
+   struct flock fl;
+   fl.l_type = F_WRLCK;
+   fl.l_whence = SEEK_SET;
+   fl.l_start = 0;
+   fl.l_len = 0;
+   if (fcntl(FD,F_SETLK,&fl) == -1)
+   {
+      // always close to not leak resources
+      int Tmp = errno;
+
+      if ((errno == EACCES || errno == EAGAIN))
+      {
+	 fl.l_type = F_WRLCK;
+	 fl.l_whence = SEEK_SET;
+	 fl.l_start = 0;
+	 fl.l_len = 0;
+	 fl.l_pid = -1;
+	 fcntl(FD, F_GETLK, &fl);
+      }
+      else
+      {
+	 fl.l_pid = -1;
+      }
+      close(FD);
+      errno = Tmp;
+
+      if (errno == ENOLCK)
+      {
+	 _error->Warning(_("Not using locking for nfs mounted lock file %s"),File.c_str());
+	 return dup(0);       // Need something for the caller to close	 
+      }
+  
+      if (Errors == true)
+      {
+	 // We only do the lookup in the if ((errno == EACCES || errno == EAGAIN))
+	 // case, so we do not need to show the errno strerrr here...
+	 if (fl.l_pid != -1)
+	 {
+	    auto name = GetProcessName(fl.l_pid);
+	    if (name.empty())
+	       _error->Error(_("Could not get lock %s. It is held by process %d"), File.c_str(), fl.l_pid);
+	    else
+	       _error->Error(_("Could not get lock %s. It is held by process %d (%s)"), File.c_str(), fl.l_pid, name.c_str());
+	 }
+	 else
+	    _error->Errno("open", _("Could not get lock %s"), File.c_str());
+
+	 _error->Notice(_("Be aware that removing the lock file is not a solution and may break your system."));
+      }
+
+      return -1;
+   }
+
+   return FD;
+}
+									/*}}}*/
+// FileExists - Check if a file exists					/*{{{*/
+// ---------------------------------------------------------------------
+/* Beware: Directories are also files! */
+bool FileExists(string File)
+{
+   struct stat Buf;
+   if (stat(File.c_str(),&Buf) != 0)
+      return false;
+   return true;
+}
+									/*}}}*/
+// RealFileExists - Check if a file exists and if it is really a file	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RealFileExists(string File)
+{
+   struct stat Buf;
+   if (stat(File.c_str(),&Buf) != 0)
+      return false;
+   return ((Buf.st_mode & S_IFREG) != 0);
+}
+									/*}}}*/
+// DirectoryExists - Check if a directory exists and is really one	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool DirectoryExists(string const &Path)
+{
+   struct stat Buf;
+   if (stat(Path.c_str(),&Buf) != 0)
+      return false;
+   return ((Buf.st_mode & S_IFDIR) != 0);
+}
+									/*}}}*/
+// CreateDirectory - poor man's mkdir -p guarded by a parent directory	/*{{{*/
+// ---------------------------------------------------------------------
+/* This method will create all directories needed for path in good old
+   mkdir -p style but refuses to do this if Parent is not a prefix of
+   this Path. Example: /var/cache/ and /var/cache/apt/archives are given,
+   so it will create apt/archives if /var/cache exists - on the other
+   hand if the parent is /var/lib the creation will fail as this path
+   is not a parent of the path to be generated. */
+bool CreateDirectory(string const &Parent, string const &Path)
+{
+   if (Parent.empty() == true || Path.empty() == true)
+      return false;
+
+   if (DirectoryExists(Path) == true)
+      return true;
+
+   if (DirectoryExists(Parent) == false)
+      return false;
+
+   // we are not going to create directories "into the blue"
+   if (Path.compare(0, Parent.length(), Parent) != 0)
+      return false;
+
+   vector<string> const dirs = VectorizeString(Path.substr(Parent.size()), '/');
+   string progress = Parent;
+   for (vector<string>::const_iterator d = dirs.begin(); d != dirs.end(); ++d)
+   {
+      if (d->empty() == true)
+	 continue;
+
+      progress.append("/").append(*d);
+      if (DirectoryExists(progress) == true)
+	 continue;
+
+      if (mkdir(progress.c_str(), 0755) != 0)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+// CreateAPTDirectoryIfNeeded - ensure that the given directory exists		/*{{{*/
+// ---------------------------------------------------------------------
+/* a small wrapper around CreateDirectory to check if it exists and to
+   remove the trailing "/apt/" from the parent directory if needed */
+bool CreateAPTDirectoryIfNeeded(string const &Parent, string const &Path)
+{
+   if (DirectoryExists(Path) == true)
+      return true;
+
+   size_t const len = Parent.size();
+   if (len > 5 && Parent.find("/apt/", len - 6, 5) == len - 5)
+   {
+      if (CreateDirectory(Parent.substr(0,len-5), Path) == true)
+	 return true;
+   }
+   else if (CreateDirectory(Parent, Path) == true)
+      return true;
+
+   return false;
+}
+									/*}}}*/
+// GetListOfFilesInDir - returns a vector of files in the given dir	/*{{{*/
+// ---------------------------------------------------------------------
+/* If an extension is given only files with this extension are included
+   in the returned vector, otherwise every "normal" file is included. */
+std::vector<string> GetListOfFilesInDir(string const &Dir, string const &Ext,
+					bool const &SortList, bool const &AllowNoExt)
+{
+   std::vector<string> ext;
+   ext.reserve(2);
+   if (Ext.empty() == false)
+      ext.push_back(Ext);
+   if (AllowNoExt == true && ext.empty() == false)
+      ext.push_back("");
+   return GetListOfFilesInDir(Dir, ext, SortList);
+}
+std::vector<string> GetListOfFilesInDir(string const &Dir, std::vector<string> const &Ext,
+					bool const &SortList)
+{
+   // Attention debuggers: need to be set with the environment config file!
+   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
+   if (Debug == true)
+   {
+      std::clog << "Accept in " << Dir << " only files with the following " << Ext.size() << " extensions:" << std::endl;
+      if (Ext.empty() == true)
+	 std::clog << "\tNO extension" << std::endl;
+      else
+	 for (std::vector<string>::const_iterator e = Ext.begin();
+	      e != Ext.end(); ++e)
+	    std::clog << '\t' << (e->empty() == true ? "NO" : *e) << " extension" << std::endl;
+   }
+
+   std::vector<string> List;
+
+   if (DirectoryExists(Dir) == false)
+   {
+      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
+      return List;
+   }
+
+   Configuration::MatchAgainstConfig SilentIgnore("Dir::Ignore-Files-Silently");
+   DIR *D = opendir(Dir.c_str());
+   if (D == 0) 
+   {
+      if (errno == EACCES)
+	 _error->WarningE("opendir", _("Unable to read %s"), Dir.c_str());
+      else
+	 _error->Errno("opendir", _("Unable to read %s"), Dir.c_str());
+      return List;
+   }
+
+   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
+   {
+      // skip "hidden" files
+      if (Ent->d_name[0] == '.')
+	 continue;
+
+      // Make sure it is a file and not something else
+      string const File = flCombine(Dir,Ent->d_name);
+#ifdef _DIRENT_HAVE_D_TYPE
+      if (Ent->d_type != DT_REG)
+#endif
+      {
+	 if (RealFileExists(File) == false)
+	 {
+	    // do not show ignoration warnings for directories
+	    if (
+#ifdef _DIRENT_HAVE_D_TYPE
+		Ent->d_type == DT_DIR ||
+#endif
+		DirectoryExists(File) == true)
+	       continue;
+	    if (SilentIgnore.Match(Ent->d_name) == false)
+	       _error->Notice(_("Ignoring '%s' in directory '%s' as it is not a regular file"), Ent->d_name, Dir.c_str());
+	    continue;
+	 }
+      }
+
+      // check for accepted extension:
+      // no extension given -> periods are bad as hell!
+      // extensions given -> "" extension allows no extension
+      if (Ext.empty() == false)
+      {
+	 string d_ext = flExtension(Ent->d_name);
+	 if (d_ext == Ent->d_name) // no extension
+	 {
+	    if (std::find(Ext.begin(), Ext.end(), "") == Ext.end())
+	    {
+	       if (Debug == true)
+		  std::clog << "Bad file: " << Ent->d_name << " → no extension" << std::endl;
+	       if (SilentIgnore.Match(Ent->d_name) == false)
+		  _error->Notice(_("Ignoring file '%s' in directory '%s' as it has no filename extension"), Ent->d_name, Dir.c_str());
+	       continue;
+	    }
+	 }
+	 else if (std::find(Ext.begin(), Ext.end(), d_ext) == Ext.end())
+	 {
+	    if (Debug == true)
+	       std::clog << "Bad file: " << Ent->d_name << " → bad extension »" << flExtension(Ent->d_name) << "«" << std::endl;
+	    if (SilentIgnore.Match(Ent->d_name) == false)
+	       _error->Notice(_("Ignoring file '%s' in directory '%s' as it has an invalid filename extension"), Ent->d_name, Dir.c_str());
+	    continue;
+	 }
+      }
+
+      // Skip bad filenames ala run-parts
+      const char *C = Ent->d_name;
+      for (; *C != 0; ++C)
+	 if (isalpha(*C) == 0 && isdigit(*C) == 0
+	     && *C != '_' && *C != '-' && *C != ':') {
+	    // no required extension -> dot is a bad character
+	    if (*C == '.' && Ext.empty() == false)
+	       continue;
+	    break;
+	 }
+
+      // we don't reach the end of the name -> bad character included
+      if (*C != 0)
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → bad character »"
+	       << *C << "« in filename (period allowed: " << (Ext.empty() ? "no" : "yes") << ")" << std::endl;
+	 continue;
+      }
+
+      // skip filenames which end with a period. These are never valid
+      if (*(C - 1) == '.')
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
+	 continue;
+      }
+
+      if (Debug == true)
+	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
+      List.push_back(File);
+   }
+   closedir(D);
+
+   if (SortList == true)
+      std::sort(List.begin(),List.end());
+   return List;
+}
+std::vector<string> GetListOfFilesInDir(string const &Dir, bool SortList)
+{
+   bool const Debug = _config->FindB("Debug::GetListOfFilesInDir", false);
+   if (Debug == true)
+      std::clog << "Accept in " << Dir << " all regular files" << std::endl;
+
+   std::vector<string> List;
+
+   if (DirectoryExists(Dir) == false)
+   {
+      _error->Error(_("List of files can't be created as '%s' is not a directory"), Dir.c_str());
+      return List;
+   }
+
+   DIR *D = opendir(Dir.c_str());
+   if (D == 0)
+   {
+      _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
+      return List;
+   }
+
+   for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) 
+   {
+      // skip "hidden" files
+      if (Ent->d_name[0] == '.')
+	 continue;
+
+      // Make sure it is a file and not something else
+      string const File = flCombine(Dir,Ent->d_name);
+#ifdef _DIRENT_HAVE_D_TYPE
+      if (Ent->d_type != DT_REG)
+#endif
+      {
+	 if (RealFileExists(File) == false)
+	 {
+	    if (Debug == true)
+	       std::clog << "Bad file: " << Ent->d_name << " → it is not a real file" << std::endl;
+	    continue;
+	 }
+      }
+
+      // Skip bad filenames ala run-parts
+      const char *C = Ent->d_name;
+      for (; *C != 0; ++C)
+	 if (isalpha(*C) == 0 && isdigit(*C) == 0
+	     && *C != '_' && *C != '-' && *C != '.')
+	    break;
+
+      // we don't reach the end of the name -> bad character included
+      if (*C != 0)
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → bad character »" << *C << "« in filename" << std::endl;
+	 continue;
+      }
+
+      // skip filenames which end with a period. These are never valid
+      if (*(C - 1) == '.')
+      {
+	 if (Debug == true)
+	    std::clog << "Bad file: " << Ent->d_name << " → Period as last character" << std::endl;
+	 continue;
+      }
+
+      if (Debug == true)
+	 std::clog << "Accept file: " << Ent->d_name << " in " << Dir << std::endl;
+      List.push_back(File);
+   }
+   closedir(D);
+
+   if (SortList == true)
+      std::sort(List.begin(),List.end());
+   return List;
+}
+									/*}}}*/
+// SafeGetCWD - This is a safer getcwd that returns a dynamic string	/*{{{*/
+// ---------------------------------------------------------------------
+/* We return / on failure. */
+string SafeGetCWD()
+{
+   // Stash the current dir.
+   char S[300];
+   S[0] = 0;
+   if (getcwd(S,sizeof(S)-2) == 0)
+      return "/";
+   unsigned int Len = strlen(S);
+   S[Len] = '/';
+   S[Len+1] = 0;
+   return S;
+}
+									/*}}}*/
+// GetModificationTime - Get the mtime of the given file or -1 on error /*{{{*/
+// ---------------------------------------------------------------------
+/* We return / on failure. */
+time_t GetModificationTime(string const &Path)
+{
+   struct stat St;
+   if (stat(Path.c_str(), &St) < 0)
+      return -1;
+   return  St.st_mtime;
+}
+									/*}}}*/
+// flNotDir - Strip the directory from the filename			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flNotDir(string File)
+{
+   string::size_type Res = File.rfind('/');
+   if (Res == string::npos)
+      return File;
+   Res++;
+   return string(File,Res,Res - File.length());
+}
+									/*}}}*/
+// flNotFile - Strip the file from the directory name			/*{{{*/
+// ---------------------------------------------------------------------
+/* Result ends in a / */
+string flNotFile(string File)
+{
+   string::size_type Res = File.rfind('/');
+   if (Res == string::npos)
+      return "./";
+   Res++;
+   return string(File,0,Res);
+}
+									/*}}}*/
+// flExtension - Return the extension for the file			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flExtension(string File)
+{
+   string::size_type Res = File.rfind('.');
+   if (Res == string::npos)
+      return File;
+   Res++;
+   return string(File,Res);
+}
+									/*}}}*/
+// flNoLink - If file is a symlink then deref it			/*{{{*/
+// ---------------------------------------------------------------------
+/* If the name is not a link then the returned path is the input. */
+string flNoLink(string File)
+{
+   struct stat St;
+   if (lstat(File.c_str(),&St) != 0 || S_ISLNK(St.st_mode) == 0)
+      return File;
+   if (stat(File.c_str(),&St) != 0)
+      return File;
+   
+   /* Loop resolving the link. There is no need to limit the number of 
+      loops because the stat call above ensures that the symlink is not 
+      circular */
+   char Buffer[1024];
+   string NFile = File;
+   while (1)
+   {
+      // Read the link
+      ssize_t Res;
+      if ((Res = readlink(NFile.c_str(),Buffer,sizeof(Buffer))) <= 0 || 
+	  (size_t)Res >= sizeof(Buffer))
+	  return File;
+      
+      // Append or replace the previous path
+      Buffer[Res] = 0;
+      if (Buffer[0] == '/')
+	 NFile = Buffer;
+      else
+	 NFile = flNotFile(NFile) + Buffer;
+      
+      // See if we are done
+      if (lstat(NFile.c_str(),&St) != 0)
+	 return File;
+      if (S_ISLNK(St.st_mode) == 0)
+	 return NFile;      
+   }   
+}
+									/*}}}*/
+// flCombine - Combine a file and a directory				/*{{{*/
+// ---------------------------------------------------------------------
+/* If the file is an absolute path then it is just returned, otherwise
+   the directory is pre-pended to it. */
+string flCombine(string Dir,string File)
+{
+   if (File.empty() == true)
+      return string();
+   
+   if (File[0] == '/' || Dir.empty() == true)
+      return File;
+   if (File.length() >= 2 && File[0] == '.' && File[1] == '/')
+      return File;
+   if (Dir[Dir.length()-1] == '/')
+      return Dir + File;
+   return Dir + '/' + File;
+}
+									/*}}}*/
+// flAbsPath - Return the absolute path of the filename			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string flAbsPath(string File)
+{
+   char *p = realpath(File.c_str(), NULL);
+   if (p == NULL)
+   {
+      _error->Errno("realpath", "flAbsPath on %s failed", File.c_str());
+      return "";
+   }
+   std::string AbsPath(p);
+   free(p);
+   return AbsPath;
+}
+									/*}}}*/
+std::string flNormalize(std::string file)				/*{{{*/
+{
+   if (file.empty())
+      return file;
+   // do some normalisation by removing // and /./ from the path
+   size_t found = string::npos;
+   while ((found = file.find("/./")) != string::npos)
+      file.replace(found, 3, "/");
+   while ((found = file.find("//")) != string::npos)
+      file.replace(found, 2, "/");
+
+   if (APT::String::Startswith(file, "/dev/null"))
+   {
+      file.erase(strlen("/dev/null"));
+      return file;
+   }
+   return file;
+}
+									/*}}}*/
+// SetCloseExec - Set the close on exec flag				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void SetCloseExec(int Fd,bool Close)
+{   
+   if (fcntl(Fd,F_SETFD,(Close == false)?0:FD_CLOEXEC) != 0)
+   {
+      cerr << "FATAL -> Could not set close on exec " << strerror(errno) << endl;
+      exit(100);
+   }
+}
+									/*}}}*/
+// SetNonBlock - Set the nonblocking flag				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void SetNonBlock(int Fd,bool Block)
+{   
+   int Flags = fcntl(Fd,F_GETFL) & (~O_NONBLOCK);
+   if (fcntl(Fd,F_SETFL,Flags | ((Block == false)?0:O_NONBLOCK)) != 0)
+   {
+      cerr << "FATAL -> Could not set non-blocking flag " << strerror(errno) << endl;
+      exit(100);
+   }
+}
+									/*}}}*/
+// WaitFd - Wait for a FD to become readable				/*{{{*/
+// ---------------------------------------------------------------------
+/* This waits for a FD to become readable using select. It is useful for
+   applications making use of non-blocking sockets. The timeout is 
+   in seconds. */
+bool WaitFd(int Fd,bool write,unsigned long timeout)
+{
+   fd_set Set;
+   struct timeval tv;
+   FD_ZERO(&Set);
+   FD_SET(Fd,&Set);
+   tv.tv_sec = timeout;
+   tv.tv_usec = 0;
+   if (write == true) 
+   {      
+      int Res;
+      do
+      {
+	 Res = select(Fd+1,0,&Set,0,(timeout != 0?&tv:0));
+      }
+      while (Res < 0 && errno == EINTR);
+      
+      if (Res <= 0)
+	 return false;
+   } 
+   else 
+   {
+      int Res;
+      do
+      {
+	 Res = select(Fd+1,&Set,0,0,(timeout != 0?&tv:0));
+      }
+      while (Res < 0 && errno == EINTR);
+      
+      if (Res <= 0)
+	 return false;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// MergeKeepFdsFromConfiguration - Merge APT::Keep-Fds configuration	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to merge the APT::Keep-Fds with the provided KeepFDs
+ * set.
+ */
+void MergeKeepFdsFromConfiguration(std::set<int> &KeepFDs)
+{
+      Configuration::Item const *Opts = _config->Tree("APT::Keep-Fds");
+      if (Opts != 0 && Opts->Child != 0)
+      {
+	 Opts = Opts->Child;
+	 for (; Opts != 0; Opts = Opts->Next)
+	 {
+	    if (Opts->Value.empty() == true)
+	       continue;
+	    int fd = atoi(Opts->Value.c_str());
+	    KeepFDs.insert(fd);
+	 }
+      }
+}
+									/*}}}*/
+// ExecFork - Magical fork that sanitizes the context before execing	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used if you want to cleanse the environment for the forked 
+   child, it fixes up the important signals and nukes all of the fds,
+   otherwise acts like normal fork. */
+pid_t ExecFork()
+{
+      set<int> KeepFDs;
+      // we need to merge the Keep-Fds as external tools like 
+      // debconf-apt-progress use it
+      MergeKeepFdsFromConfiguration(KeepFDs);
+      return ExecFork(KeepFDs);
+}
+
+pid_t ExecFork(std::set<int> KeepFDs)
+{
+   // Fork off the process
+   pid_t Process = fork();
+   if (Process < 0)
+   {
+      cerr << "FATAL -> Failed to fork." << endl;
+      exit(100);
+   }
+
+   // Spawn the subprocess
+   if (Process == 0)
+   {
+      // Setup the signals
+      signal(SIGPIPE,SIG_DFL);
+      signal(SIGQUIT,SIG_DFL);
+      signal(SIGINT,SIG_DFL);
+      signal(SIGWINCH,SIG_DFL);
+      signal(SIGCONT,SIG_DFL);
+      signal(SIGTSTP,SIG_DFL);
+
+      DIR *dir = opendir("/proc/self/fd");
+      if (dir != NULL)
+      {
+	 struct dirent *ent;
+	 while ((ent = readdir(dir)))
+	 {
+	    int fd = atoi(ent->d_name);
+	    // If fd > 0, it was a fd number and not . or ..
+	    if (fd >= 3 && KeepFDs.find(fd) == KeepFDs.end())
+	       fcntl(fd,F_SETFD,FD_CLOEXEC);
+	 }
+	 closedir(dir);
+      } else {
+	 long ScOpenMax = sysconf(_SC_OPEN_MAX);
+	 // Close all of our FDs - just in case
+	 for (int K = 3; K != ScOpenMax; K++)
+	 {
+	    if(KeepFDs.find(K) == KeepFDs.end())
+	       fcntl(K,F_SETFD,FD_CLOEXEC);
+	 }
+      }
+   }
+   
+   return Process;
+}
+									/*}}}*/
+// ExecWait - Fancy waitpid						/*{{{*/
+// ---------------------------------------------------------------------
+/* Waits for the given sub process. If Reap is set then no errors are 
+   generated. Otherwise a failed subprocess will generate a proper descriptive
+   message */
+bool ExecWait(pid_t Pid,const char *Name,bool Reap)
+{
+   if (Pid <= 1)
+      return true;
+   
+   // Wait and collect the error code
+   int Status;
+   while (waitpid(Pid,&Status,0) != Pid)
+   {
+      if (errno == EINTR)
+	 continue;
+
+      if (Reap == true)
+	 return false;
+      
+      return _error->Error(_("Waited for %s but it wasn't there"),Name);
+   }
+
+   
+   // Check for an error code.
+   if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
+   {
+      if (Reap == true)
+	 return false;
+      if (WIFSIGNALED(Status) != 0)
+      {
+	 if( WTERMSIG(Status) == SIGSEGV)
+	    return _error->Error(_("Sub-process %s received a segmentation fault."),Name);
+	 else 
+	    return _error->Error(_("Sub-process %s received signal %u."),Name, WTERMSIG(Status));
+      }
+
+      if (WIFEXITED(Status) != 0)
+	 return _error->Error(_("Sub-process %s returned an error code (%u)"),Name,WEXITSTATUS(Status));
+      
+      return _error->Error(_("Sub-process %s exited unexpectedly"),Name);
+   }      
+   
+   return true;
+}
+									/*}}}*/
+// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned	/*{{{*/
+bool StartsWithGPGClearTextSignature(string const &FileName)
+{
+   FILE* gpg = fopen(FileName.c_str(), "r");
+   if (gpg == nullptr)
+      return false;
+
+   char * lineptr = nullptr;
+   size_t n = 0;
+   errno = 0;
+   ssize_t const result = getline(&lineptr, &n, gpg);
+   if (errno != 0)
+   {
+      _error->Errno("getline", "Could not read from %s", FileName.c_str());
+      fclose(gpg);
+      free(lineptr);
+      return false;
+   }
+   fclose(gpg);
+
+   _strrstrip(lineptr);
+   static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----";
+   if (result == -1 || strcmp(lineptr, SIGMSG) != 0)
+   {
+      free(lineptr);
+      return false;
+   }
+   free(lineptr);
+   return true;
+}
+									/*}}}*/
+// ChangeOwnerAndPermissionOfFile - set file attributes to requested values /*{{{*/
+bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode)
+{
+   if (strcmp(file, "/dev/null") == 0)
+      return true;
+   bool Res = true;
+   if (getuid() == 0 && strlen(user) != 0 && strlen(group) != 0) // if we aren't root, we can't chown, so don't try it
+   {
+      // ensure the file is owned by root and has good permissions
+      struct passwd const * const pw = getpwnam(user);
+      struct group const * const gr = getgrnam(group);
+      if (pw != NULL && gr != NULL && lchown(file, pw->pw_uid, gr->gr_gid) != 0)
+	 Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file);
+   }
+   struct stat Buf;
+   if (lstat(file, &Buf) != 0 || S_ISLNK(Buf.st_mode))
+      return Res;
+   if (chmod(file, mode) != 0)
+      Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file);
+   return Res;
+}
+									/*}}}*/
+
+struct APT_HIDDEN simple_buffer {							/*{{{*/
+   size_t buffersize_max = 0;
+   unsigned long long bufferstart = 0;
+   unsigned long long bufferend = 0;
+   char *buffer = nullptr;
+
+   simple_buffer() {
+      reset(4096);
+   }
+   ~simple_buffer() {
+      delete[] buffer;
+   }
+
+   const char *get() const { return buffer + bufferstart; }
+   char *get() { return buffer + bufferstart; }
+   const char *getend() const { return buffer + bufferend; }
+   char *getend() { return buffer + bufferend; }
+   bool empty() const { return bufferend <= bufferstart; }
+   bool full() const { return bufferend == buffersize_max; }
+   unsigned long long free() const { return buffersize_max - bufferend; }
+   unsigned long long size() const { return bufferend-bufferstart; }
+   void reset(size_t size)
+   {
+      if (size > buffersize_max) {
+	 delete[] buffer;
+	 buffersize_max = size;
+	 buffer = new char[size];
+      }
+      reset();
+   }
+   void reset() { bufferend = bufferstart = 0; }
+   ssize_t read(void *to, unsigned long long requested_size) APT_MUSTCHECK
+   {
+      if (size() < requested_size)
+	 requested_size = size();
+      memcpy(to, buffer + bufferstart, requested_size);
+      bufferstart += requested_size;
+      if (bufferstart == bufferend)
+	 bufferstart = bufferend = 0;
+      return requested_size;
+   }
+   ssize_t write(const void *from, unsigned long long requested_size) APT_MUSTCHECK
+   {
+      if (free() < requested_size)
+	 requested_size = free();
+      memcpy(getend(), from, requested_size);
+      bufferend += requested_size;
+      if (bufferstart == bufferend)
+	 bufferstart = bufferend = 0;
+      return requested_size;
+   }
+};
+									/*}}}*/
+
+class APT_HIDDEN FileFdPrivate {							/*{{{*/
+   friend class BufferedWriteFileFdPrivate;
+protected:
+   FileFd * const filefd;
+   simple_buffer buffer;
+   int compressed_fd;
+   pid_t compressor_pid;
+   bool is_pipe;
+   APT::Configuration::Compressor compressor;
+   unsigned int openmode;
+   unsigned long long seekpos;
+public:
+
+   explicit FileFdPrivate(FileFd * const pfilefd) : filefd(pfilefd),
+      compressed_fd(-1), compressor_pid(-1), is_pipe(false),
+      openmode(0), seekpos(0) {};
+   virtual APT::Configuration::Compressor get_compressor() const
+   {
+      return compressor;
+   }
+   virtual void set_compressor(APT::Configuration::Compressor const &compressor)
+   {
+      this->compressor = compressor;
+   }
+   virtual unsigned int get_openmode() const
+   {
+      return openmode;
+   }
+   virtual void set_openmode(unsigned int openmode)
+   {
+      this->openmode = openmode;
+   }
+   virtual bool get_is_pipe() const
+   {
+      return is_pipe;
+   }
+   virtual void set_is_pipe(bool is_pipe)
+   {
+      this->is_pipe = is_pipe;
+   }
+   virtual unsigned long long get_seekpos() const
+   {
+      return seekpos;
+   }
+   virtual void set_seekpos(unsigned long long seekpos)
+   {
+      this->seekpos = seekpos;
+   }
+
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) = 0;
+   ssize_t InternalRead(void * To, unsigned long long Size)
+   {
+      // Drain the buffer if needed.
+      if (buffer.empty() == false)
+      {
+	 return buffer.read(To, Size);
+      }
+      return InternalUnbufferedRead(To, Size);
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) = 0;
+   virtual bool InternalReadError() { return filefd->FileFdErrno("read",_("Read error")); }
+   virtual char * InternalReadLine(char * To, unsigned long long Size)
+   {
+      if (unlikely(Size == 0))
+	 return nullptr;
+      // Read one byte less than buffer size to have space for trailing 0.
+      --Size;
+
+      char * const InitialTo = To;
+
+      while (Size > 0) {
+	 if (buffer.empty() == true)
+	 {
+	    buffer.reset();
+	    unsigned long long actualread = 0;
+	    if (filefd->Read(buffer.getend(), buffer.free(), &actualread) == false)
+	       return nullptr;
+	    buffer.bufferend = actualread;
+	    if (buffer.size() == 0)
+	    {
+	       if (To == InitialTo)
+		  return nullptr;
+	       break;
+	    }
+	    filefd->Flags &= ~FileFd::HitEof;
+	 }
+
+	 unsigned long long const OutputSize = std::min(Size, buffer.size());
+	 char const * const newline = static_cast<char const *>(memchr(buffer.get(), '\n', OutputSize));
+	 // Read until end of line or up to Size bytes from the buffer.
+	 unsigned long long actualread = buffer.read(To,
+						     (newline != nullptr)
+						     ? (newline - buffer.get()) + 1
+						     : OutputSize);
+	 To += actualread;
+	 Size -= actualread;
+	 if (newline != nullptr)
+	    break;
+      }
+      *To = '\0';
+      return InitialTo;
+   }
+   virtual bool InternalFlush()
+   {
+      return true;
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) = 0;
+   virtual bool InternalWriteError() { return filefd->FileFdErrno("write",_("Write error")); }
+   virtual bool InternalSeek(unsigned long long const To)
+   {
+      // Our poor man seeking is costly, so try to avoid it
+      unsigned long long const iseekpos = filefd->Tell();
+      if (iseekpos == To)
+	 return true;
+      else if (iseekpos < To)
+	 return filefd->Skip(To - iseekpos);
+
+      if ((openmode & FileFd::ReadOnly) != FileFd::ReadOnly)
+	 return filefd->FileFdError("Reopen is only implemented for read-only files!");
+      InternalClose(filefd->FileName);
+      if (filefd->iFd != -1)
+	 close(filefd->iFd);
+      filefd->iFd = -1;
+      if (filefd->TemporaryFileName.empty() == false)
+	 filefd->iFd = open(filefd->TemporaryFileName.c_str(), O_RDONLY);
+      else if (filefd->FileName.empty() == false)
+	 filefd->iFd = open(filefd->FileName.c_str(), O_RDONLY);
+      else
+      {
+	 if (compressed_fd > 0)
+	    if (lseek(compressed_fd, 0, SEEK_SET) != 0)
+	       filefd->iFd = compressed_fd;
+	 if (filefd->iFd < 0)
+	    return filefd->FileFdError("Reopen is not implemented for pipes opened with FileFd::OpenDescriptor()!");
+      }
+
+      if (filefd->OpenInternDescriptor(openmode, compressor) == false)
+	 return filefd->FileFdError("Seek on file %s because it couldn't be reopened", filefd->FileName.c_str());
+
+      buffer.reset();
+      set_seekpos(0);
+      if (To != 0)
+	 return filefd->Skip(To);
+
+      seekpos = To;
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over)
+   {
+      unsigned long long constexpr buffersize = 1024;
+      char buffer[buffersize];
+      while (Over != 0)
+      {
+	 unsigned long long toread = std::min(buffersize, Over);
+	 if (filefd->Read(buffer, toread) == false)
+	    return filefd->FileFdError("Unable to seek ahead %llu",Over);
+	 Over -= toread;
+      }
+      return true;
+   }
+   virtual bool InternalTruncate(unsigned long long const)
+   {
+      return filefd->FileFdError("Truncating compressed files is not implemented (%s)", filefd->FileName.c_str());
+   }
+   virtual unsigned long long InternalTell()
+   {
+      // In theory, we could just return seekpos here always instead of
+      // seeking around, but not all users of FileFd use always Seek() and co
+      // so d->seekpos isn't always true and we can just use it as a hint if
+      // we have nothing else, but not always as an authority…
+      return seekpos - buffer.size();
+   }
+   virtual unsigned long long InternalSize()
+   {
+      unsigned long long size = 0;
+      unsigned long long const oldSeek = filefd->Tell();
+      unsigned long long constexpr ignoresize = 1024;
+      char ignore[ignoresize];
+      unsigned long long read = 0;
+      do {
+	 if (filefd->Read(ignore, ignoresize, &read) == false)
+	 {
+	    filefd->Seek(oldSeek);
+	    return 0;
+	 }
+      } while(read != 0);
+      size = filefd->Tell();
+      filefd->Seek(oldSeek);
+      return size;
+   }
+   virtual bool InternalClose(std::string const &FileName) = 0;
+   virtual bool InternalStream() const { return false; }
+   virtual bool InternalAlwaysAutoClose() const { return true; }
+
+   virtual ~FileFdPrivate() {}
+};
+									/*}}}*/
+class APT_HIDDEN BufferedWriteFileFdPrivate : public FileFdPrivate {	/*{{{*/
+protected:
+   FileFdPrivate *wrapped;
+   simple_buffer writebuffer;
+
+public:
+
+   explicit BufferedWriteFileFdPrivate(FileFdPrivate *Priv) :
+      FileFdPrivate(Priv->filefd), wrapped(Priv) {};
+
+   virtual APT::Configuration::Compressor get_compressor() const APT_OVERRIDE
+   {
+      return wrapped->get_compressor();
+   }
+   virtual void set_compressor(APT::Configuration::Compressor const &compressor)  APT_OVERRIDE
+   {
+      return wrapped->set_compressor(compressor);
+   }
+   virtual unsigned int get_openmode() const  APT_OVERRIDE
+   {
+      return wrapped->get_openmode();
+   }
+   virtual void set_openmode(unsigned int openmode)  APT_OVERRIDE
+   {
+      return wrapped->set_openmode(openmode);
+   }
+   virtual bool get_is_pipe() const  APT_OVERRIDE
+   {
+      return wrapped->get_is_pipe();
+   }
+   virtual void set_is_pipe(bool is_pipe) APT_OVERRIDE
+   {
+      FileFdPrivate::set_is_pipe(is_pipe);
+      wrapped->set_is_pipe(is_pipe);
+   }
+   virtual unsigned long long get_seekpos() const APT_OVERRIDE
+   {
+      return wrapped->get_seekpos();
+   }
+   virtual void set_seekpos(unsigned long long seekpos) APT_OVERRIDE
+   {
+      return wrapped->set_seekpos(seekpos);
+   }
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalOpen(iFd, Mode);
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalUnbufferedRead(To, Size);
+
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      return wrapped->InternalReadError();
+   }
+   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return nullptr;
+      return wrapped->InternalReadLine(To, Size);
+   }
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      while (writebuffer.empty() == false) {
+	 auto written = wrapped->InternalWrite(writebuffer.get(),
+					       writebuffer.size());
+	 // Ignore interrupted syscalls
+	 if (written < 0 && errno == EINTR)
+	    continue;
+	 if (written < 0)
+	    return wrapped->InternalWriteError();
+
+	 writebuffer.bufferstart += written;
+      }
+      writebuffer.reset();
+      return wrapped->InternalFlush();
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // Optimisation: If the buffer is empty and we have more to write than
+      // would fit in the buffer (or equal number of bytes), write directly.
+      if (writebuffer.empty() == true && Size >= writebuffer.free())
+	 return wrapped->InternalWrite(From, Size);
+
+      // Write as much into the buffer as possible and then flush if needed
+      auto written = writebuffer.write(From, Size);
+
+      if (writebuffer.full() && InternalFlush() == false)
+	 return -1;
+
+      return written;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      return wrapped->InternalWriteError();
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalSeek(To);
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalSkip(Over);
+   }
+   virtual bool InternalTruncate(unsigned long long const Size) APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return false;
+      return wrapped->InternalTruncate(Size);
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalTell();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      if (InternalFlush() == false)
+	 return -1;
+      return wrapped->InternalSize();
+   }
+   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
+   {
+      return wrapped->InternalClose(FileName);
+   }
+   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE
+   {
+      return wrapped->InternalAlwaysAutoClose();
+   }
+   virtual ~BufferedWriteFileFdPrivate()
+   {
+      delete wrapped;
+   }
+};
+									/*}}}*/
+class APT_HIDDEN GzipFileFdPrivate: public FileFdPrivate {				/*{{{*/
+#ifdef HAVE_ZLIB
+public:
+   gzFile gz;
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 gz = gzdopen(iFd, "r+");
+      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 gz = gzdopen(iFd, "w");
+      else
+	 gz = gzdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      return gz != nullptr;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return gzread(gz, To, Size);
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = gzerror(gz, &err);
+      if (err != Z_ERRNO)
+	 return filefd->FileFdError("gzread: %s (%d: %s)", _("Read error"), err, errmsg);
+      return FileFdPrivate::InternalReadError();
+   }
+   virtual char * InternalReadLine(char * To, unsigned long long Size) APT_OVERRIDE
+   {
+      return gzgets(gz, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return gzwrite(gz,From,Size);
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = gzerror(gz, &err);
+      if (err != Z_ERRNO)
+	 return filefd->FileFdError("gzwrite: %s (%d: %s)", _("Write error"), err, errmsg);
+      return FileFdPrivate::InternalWriteError();
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      off_t const res = gzseek(gz, To, SEEK_SET);
+      if (res != (off_t)To)
+	 return filefd->FileFdError("Unable to seek to %llu", To);
+      seekpos = To;
+      buffer.reset();
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (Over >= buffer.size())
+      {
+	 Over -= buffer.size();
+	 buffer.reset();
+      }
+      else
+      {
+	 buffer.bufferstart += Over;
+	 return true;
+      }
+      if (Over == 0)
+	 return true;
+      off_t const res = gzseek(gz, Over, SEEK_CUR);
+      if (res < 0)
+	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
+      seekpos = res;
+      return true;
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      return gztell(gz) - buffer.size();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      unsigned long long filesize = FileFdPrivate::InternalSize();
+      // only check gzsize if we are actually a gzip file, just checking for
+      // "gz" is not sufficient as uncompressed files could be opened with
+      // gzopen in "direct" mode as well
+      if (filesize == 0 || gzdirect(gz))
+	 return filesize;
+
+      off_t const oldPos = lseek(filefd->iFd, 0, SEEK_CUR);
+      /* unfortunately zlib.h doesn't provide a gzsize(), so we have to do
+       * this ourselves; the original (uncompressed) file size is the last 32
+       * bits of the file */
+      // FIXME: Size for gz-files is limited by 32bit… no largefile support
+      if (lseek(filefd->iFd, -4, SEEK_END) < 0)
+      {
+	 filefd->FileFdErrno("lseek","Unable to seek to end of gzipped file");
+	 return 0;
+      }
+      uint32_t size = 0;
+      if (read(filefd->iFd, &size, 4) != 4)
+      {
+	 filefd->FileFdErrno("read","Unable to read original size of gzipped file");
+	 return 0;
+      }
+      size = le32toh(size);
+
+      if (lseek(filefd->iFd, oldPos, SEEK_SET) < 0)
+      {
+	 filefd->FileFdErrno("lseek","Unable to seek in gzipped file");
+	 return 0;
+      }
+      return size;
+   }
+   virtual bool InternalClose(std::string const &FileName) APT_OVERRIDE
+   {
+      if (gz == nullptr)
+	 return true;
+      int const e = gzclose(gz);
+      gz = nullptr;
+      // gzdclose() on empty files always fails with "buffer error" here, ignore that
+      if (e != 0 && e != Z_BUF_ERROR)
+	 return _error->Errno("close",_("Problem closing the gzip file %s"), FileName.c_str());
+      return true;
+   }
+
+   explicit GzipFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), gz(nullptr) {}
+   virtual ~GzipFileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN Bz2FileFdPrivate: public FileFdPrivate {				/*{{{*/
+#ifdef HAVE_BZ2
+   BZFILE* bz2;
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 bz2 = BZ2_bzdopen(iFd, "r+");
+      else if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 bz2 = BZ2_bzdopen(iFd, "w");
+      else
+	 bz2 = BZ2_bzdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      return bz2 != nullptr;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return BZ2_bzread(bz2, To, Size);
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = BZ2_bzerror(bz2, &err);
+      if (err != BZ_IO_ERROR)
+	 return filefd->FileFdError("BZ2_bzread: %s %s (%d: %s)", filefd->FileName.c_str(), _("Read error"), err, errmsg);
+      return FileFdPrivate::InternalReadError();
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return BZ2_bzwrite(bz2, (void*)From, Size);
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      int err;
+      char const * const errmsg = BZ2_bzerror(bz2, &err);
+      if (err != BZ_IO_ERROR)
+	 return filefd->FileFdError("BZ2_bzwrite: %s %s (%d: %s)", filefd->FileName.c_str(), _("Write error"), err, errmsg);
+      return FileFdPrivate::InternalWriteError();
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      if (bz2 == nullptr)
+	 return true;
+      BZ2_bzclose(bz2);
+      bz2 = nullptr;
+      return true;
+   }
+
+   explicit Bz2FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), bz2(nullptr) {}
+   virtual ~Bz2FileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN Lz4FileFdPrivate: public FileFdPrivate {				/*{{{*/
+   static constexpr unsigned long long LZ4_HEADER_SIZE = 19;
+   static constexpr unsigned long long LZ4_FOOTER_SIZE = 4;
+#ifdef HAVE_LZ4
+   LZ4F_decompressionContext_t dctx;
+   LZ4F_compressionContext_t cctx;
+   LZ4F_errorCode_t res;
+   FileFd backend;
+   simple_buffer lz4_buffer;
+   // Count of bytes that the decompressor expects to read next, or buffer size.
+   size_t next_to_load = APT_BUFFER_SIZE;
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return _error->Error("lz4 only supports write or read mode");
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly) {
+	 res = LZ4F_createCompressionContext(&cctx, LZ4F_VERSION);
+	 lz4_buffer.reset(LZ4F_compressBound(APT_BUFFER_SIZE, nullptr)
+			  + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE);
+      } else {
+	 res = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);
+	 lz4_buffer.reset(APT_BUFFER_SIZE);
+      }
+
+      filefd->Flags |= FileFd::Compressed;
+
+      if (LZ4F_isError(res))
+	 return false;
+
+      unsigned int flags = (Mode & (FileFd::WriteOnly|FileFd::ReadOnly));
+      if (backend.OpenDescriptor(iFd, flags, FileFd::None, true) == false)
+	 return false;
+
+      // Write the file header
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 res = LZ4F_compressBegin(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
+	 if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	    return false;
+      }
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      /* Keep reading as long as the compressor still wants to read */
+      while (next_to_load) {
+	 // Fill compressed buffer;
+	 if (lz4_buffer.empty()) {
+	    unsigned long long read;
+	    /* Reset - if LZ4 decompressor wants to read more, allocate more */
+	    lz4_buffer.reset(next_to_load);
+	    if (backend.Read(lz4_buffer.getend(), lz4_buffer.free(), &read) == false)
+	       return -1;
+	    lz4_buffer.bufferend += read;
+
+	    /* Expected EOF */
+	    if (read == 0) {
+	       res = -1;
+	       return filefd->FileFdError("LZ4F: %s %s",
+					  filefd->FileName.c_str(),
+					  _("Unexpected end of file")), -1;
+	    }
+	 }
+	 // Drain compressed buffer as far as possible.
+	 size_t in = lz4_buffer.size();
+	 size_t out = Size;
+
+	 res = LZ4F_decompress(dctx, To, &out, lz4_buffer.get(), &in, nullptr);
+	 if (LZ4F_isError(res))
+	       return -1;
+
+	 next_to_load = res;
+	 lz4_buffer.bufferstart += in;
+
+	 if (out != 0)
+	    return out;
+      }
+
+      return 0;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      char const * const errmsg = LZ4F_getErrorName(res);
+
+      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Read error"), res, errmsg);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      unsigned long long const towrite = std::min(APT_BUFFER_SIZE, Size);
+
+      res = LZ4F_compressUpdate(cctx,
+				lz4_buffer.buffer, lz4_buffer.buffersize_max,
+				From, towrite, nullptr);
+
+      if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	 return -1;
+
+      return towrite;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      char const * const errmsg = LZ4F_getErrorName(res);
+
+      return filefd->FileFdError("LZ4F: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Write error"), res, errmsg);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      return backend.Flush();
+   }
+
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      /* Reset variables */
+      res = 0;
+      next_to_load = APT_BUFFER_SIZE;
+
+      if (cctx != nullptr)
+      {
+	 if (filefd->Failed() == false)
+	 {
+	    res = LZ4F_compressEnd(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, nullptr);
+	    if (LZ4F_isError(res) || backend.Write(lz4_buffer.buffer, res) == false)
+	       return false;
+	    if (!backend.Flush())
+	       return false;
+	 }
+	 if (!backend.Close())
+	    return false;
+
+	 res = LZ4F_freeCompressionContext(cctx);
+	 cctx = nullptr;
+      }
+
+      if (dctx != nullptr)
+      {
+	 res = LZ4F_freeDecompressionContext(dctx);
+	 dctx = nullptr;
+      }
+      if (backend.IsOpen())
+      {
+	 backend.Close();
+	 filefd->iFd = -1;
+      }
+
+      return LZ4F_isError(res) == false;
+   }
+
+   explicit Lz4FileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), dctx(nullptr), cctx(nullptr) {}
+   virtual ~Lz4FileFdPrivate() {
+      InternalClose("");
+   }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN ZstdFileFdPrivate : public FileFdPrivate		/*{{{*/
+{
+#ifdef HAVE_ZSTD
+   ZSTD_DStream *dctx;
+   ZSTD_CStream *cctx;
+   size_t res = 0;
+   FileFd backend;
+   simple_buffer zstd_buffer;
+   // Count of bytes that the decompressor expects to read next, or buffer size.
+   size_t next_to_load = APT_BUFFER_SIZE;
+
+   public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return _error->Error("zstd only supports write or read mode");
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 cctx = ZSTD_createCStream();
+	 res = ZSTD_initCStream(cctx, findLevel(compressor.CompressArgs));
+	 zstd_buffer.reset(APT_BUFFER_SIZE);
+      }
+      else
+      {
+	 dctx = ZSTD_createDStream();
+	 res = ZSTD_initDStream(dctx);
+	 zstd_buffer.reset(APT_BUFFER_SIZE);
+      }
+
+      filefd->Flags |= FileFd::Compressed;
+
+      if (ZSTD_isError(res))
+	 return false;
+
+      unsigned int flags = (Mode & (FileFd::WriteOnly | FileFd::ReadOnly));
+      if (backend.OpenDescriptor(iFd, flags, FileFd::None, true) == false)
+	 return false;
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void *const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      /* Keep reading as long as the compressor still wants to read */
+      while (true)
+      {
+	 // Fill compressed buffer;
+	 if (zstd_buffer.empty())
+	 {
+	    unsigned long long read;
+	    /* Reset - if LZ4 decompressor wants to read more, allocate more */
+	    zstd_buffer.reset(next_to_load);
+	    if (backend.Read(zstd_buffer.getend(), zstd_buffer.free(), &read) == false)
+	       return -1;
+	    zstd_buffer.bufferend += read;
+
+	    if (read == 0)
+	    {
+	       /* Expected EOF */
+	       if (next_to_load == 0)
+		  return 0;
+
+	       res = -1;
+	       return filefd->FileFdError("ZSTD: %s %s",
+					  filefd->FileName.c_str(),
+					  _("Unexpected end of file")),
+		      -1;
+	    }
+	 }
+	 // Drain compressed buffer as far as possible.
+	 ZSTD_inBuffer in = {
+	    .src = zstd_buffer.get(),
+	    .size = zstd_buffer.size(),
+	    .pos = 0,
+	 };
+	 ZSTD_outBuffer out = {
+	    .dst = To,
+	    .size = Size,
+	    .pos = 0,
+	 };
+
+	 next_to_load = res = ZSTD_decompressStream(dctx, &out, &in);
+
+	 if (res == 0)
+	 {
+	    res = ZSTD_initDStream(dctx);
+	 }
+
+	 if (ZSTD_isError(res))
+	    return -1;
+
+	 zstd_buffer.bufferstart += in.pos;
+
+	 if (out.pos != 0)
+	    return out.pos;
+      }
+
+      return 0;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      char const *const errmsg = ZSTD_getErrorName(res);
+
+      return filefd->FileFdError("ZSTD: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Read error"), res, errmsg);
+   }
+   virtual ssize_t InternalWrite(void const *const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // Drain compressed buffer as far as possible.
+      ZSTD_outBuffer out = {
+	 .dst = zstd_buffer.buffer,
+	 .size = zstd_buffer.buffersize_max,
+	 .pos = 0,
+      };
+      ZSTD_inBuffer in = {
+	 .src = From,
+	 .size = Size,
+	 .pos = 0,
+      };
+
+      res = ZSTD_compressStream(cctx, &out, &in);
+
+      if (ZSTD_isError(res) || backend.Write(zstd_buffer.buffer, out.pos) == false)
+	 return -1;
+
+      return in.pos;
+   }
+
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      char const *const errmsg = ZSTD_getErrorName(res);
+
+      return filefd->FileFdError("ZSTD: %s %s (%zu: %s)", filefd->FileName.c_str(), _("Write error"), res, errmsg);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+
+   virtual bool InternalFlush() APT_OVERRIDE
+   {
+      return backend.Flush();
+   }
+
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      /* Reset variables */
+      res = 0;
+      next_to_load = APT_BUFFER_SIZE;
+
+      if (cctx != nullptr)
+      {
+	 if (filefd->Failed() == false)
+	 {
+	    do
+	    {
+	       ZSTD_outBuffer out = {
+		  .dst = zstd_buffer.buffer,
+		  .size = zstd_buffer.buffersize_max,
+		  .pos = 0,
+	       };
+	       res = ZSTD_endStream(cctx, &out);
+	       if (ZSTD_isError(res) || backend.Write(zstd_buffer.buffer, out.pos) == false)
+		  return false;
+	    } while (res > 0);
+
+	    if (!backend.Flush())
+	       return false;
+	 }
+	 if (!backend.Close())
+	    return false;
+
+	 res = ZSTD_freeCStream(cctx);
+	 cctx = nullptr;
+      }
+
+      if (dctx != nullptr)
+      {
+	 res = ZSTD_freeDStream(dctx);
+	 dctx = nullptr;
+      }
+      if (backend.IsOpen())
+      {
+	 backend.Close();
+	 filefd->iFd = -1;
+      }
+
+      return ZSTD_isError(res) == false;
+   }
+
+   static uint32_t findLevel(std::vector<std::string> const &Args)
+   {
+      for (auto a = Args.rbegin(); a != Args.rend(); ++a)
+      {
+	 if (a->size() >= 2 && (*a)[0] == '-' && (*a)[1] != '-')
+	 {
+	    auto const level = a->substr(1);
+	    auto const notANumber = level.find_first_not_of("0123456789");
+	    if (notANumber != std::string::npos)
+	       continue;
+
+	    return (uint32_t)stoi(level);
+	 }
+      }
+      return 19;
+   }
+
+   explicit ZstdFileFdPrivate(FileFd *const filefd) : FileFdPrivate(filefd), dctx(nullptr), cctx(nullptr) {}
+   virtual ~ZstdFileFdPrivate()
+   {
+      InternalClose("");
+   }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN LzmaFileFdPrivate: public FileFdPrivate {		/*{{{*/
+#ifdef HAVE_LZMA
+   struct LZMAFILE {
+      FILE* file;
+      FileFd * const filefd;
+      uint8_t buffer[4096];
+      lzma_stream stream;
+      lzma_ret err;
+      bool eof;
+      bool compressing;
+
+      explicit LZMAFILE(FileFd * const fd) : file(nullptr), filefd(fd), eof(false), compressing(false) { buffer[0] = '\0'; }
+      ~LZMAFILE()
+      {
+	 if (compressing == true && filefd->Failed() == false)
+	 {
+	    size_t constexpr buffersize = sizeof(buffer)/sizeof(buffer[0]);
+	    while(true)
+	    {
+	       stream.avail_out = buffersize;
+	       stream.next_out = buffer;
+	       err = lzma_code(&stream, LZMA_FINISH);
+	       if (err != LZMA_OK && err != LZMA_STREAM_END)
+	       {
+		  _error->Error("~LZMAFILE: Compress finalisation failed");
+		  break;
+	       }
+	       size_t const n =  buffersize - stream.avail_out;
+	       if (n && fwrite(buffer, 1, n, file) != n)
+	       {
+		  _error->Errno("~LZMAFILE",_("Write error"));
+		  break;
+	       }
+	       if (err == LZMA_STREAM_END)
+		  break;
+	    }
+	 }
+	 lzma_end(&stream);
+	 fclose(file);
+      }
+   };
+   LZMAFILE* lzma;
+   static uint32_t findXZlevel(std::vector<std::string> const &Args)
+   {
+      for (auto a = Args.rbegin(); a != Args.rend(); ++a)
+	 if (a->empty() == false && (*a)[0] == '-' && (*a)[1] != '-')
+	 {
+	    auto const number = a->find_last_of("0123456789");
+	    if (number == std::string::npos)
+	       continue;
+	    auto const extreme = a->find("e", number);
+	    uint32_t level = (extreme != std::string::npos) ? LZMA_PRESET_EXTREME : 0;
+	    switch ((*a)[number])
+	    {
+	       case '0': return level | 0;
+	       case '1': return level | 1;
+	       case '2': return level | 2;
+	       case '3': return level | 3;
+	       case '4': return level | 4;
+	       case '5': return level | 5;
+	       case '6': return level | 6;
+	       case '7': return level | 7;
+	       case '8': return level | 8;
+	       case '9': return level | 9;
+	    }
+	 }
+      return 6;
+   }
+public:
+   virtual bool InternalOpen(int const iFd, unsigned int const Mode) APT_OVERRIDE
+   {
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return filefd->FileFdError("ReadWrite mode is not supported for lzma/xz files %s", filefd->FileName.c_str());
+
+      if (lzma == nullptr)
+	 lzma = new LzmaFileFdPrivate::LZMAFILE(filefd);
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+	 lzma->file = fdopen(iFd, "w");
+      else
+	 lzma->file = fdopen(iFd, "r");
+      filefd->Flags |= FileFd::Compressed;
+      if (lzma->file == nullptr)
+	 return false;
+
+      lzma_stream tmp_stream = LZMA_STREAM_INIT;
+      lzma->stream = tmp_stream;
+
+      if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly)
+      {
+	 uint32_t const xzlevel = findXZlevel(compressor.CompressArgs);
+	 if (compressor.Name == "xz")
+	 {
+	    if (lzma_easy_encoder(&lzma->stream, xzlevel, LZMA_CHECK_CRC64) != LZMA_OK)
+	       return false;
+	 }
+	 else
+	 {
+	    lzma_options_lzma options;
+	    lzma_lzma_preset(&options, xzlevel);
+	    if (lzma_alone_encoder(&lzma->stream, &options) != LZMA_OK)
+	       return false;
+	 }
+	 lzma->compressing = true;
+      }
+      else
+      {
+	 uint64_t constexpr memlimit = 1024 * 1024 * 500;
+	 if (lzma_auto_decoder(&lzma->stream, memlimit, 0) != LZMA_OK)
+	    return false;
+	 lzma->compressing = false;
+      }
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      ssize_t Res;
+      if (lzma->eof == true)
+	 return 0;
+
+      lzma->stream.next_out = (uint8_t *) To;
+      lzma->stream.avail_out = Size;
+      if (lzma->stream.avail_in == 0)
+      {
+	 lzma->stream.next_in = lzma->buffer;
+	 lzma->stream.avail_in = fread(lzma->buffer, 1, sizeof(lzma->buffer)/sizeof(lzma->buffer[0]), lzma->file);
+      }
+      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
+      if (lzma->err == LZMA_STREAM_END)
+      {
+	 lzma->eof = true;
+	 Res = Size - lzma->stream.avail_out;
+      }
+      else if (lzma->err != LZMA_OK)
+      {
+	 Res = -1;
+	 errno = 0;
+      }
+      else
+      {
+	 Res = Size - lzma->stream.avail_out;
+	 if (Res == 0)
+	 {
+	    // lzma run was okay, but produced no output…
+	    Res = -1;
+	    errno = EINTR;
+	 }
+      }
+      return Res;
+   }
+   virtual bool InternalReadError() APT_OVERRIDE
+   {
+      return filefd->FileFdError("lzma_read: %s (%d)", _("Read error"), lzma->err);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      ssize_t Res;
+      lzma->stream.next_in = (uint8_t *)From;
+      lzma->stream.avail_in = Size;
+      lzma->stream.next_out = lzma->buffer;
+      lzma->stream.avail_out = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]);
+      lzma->err = lzma_code(&lzma->stream, LZMA_RUN);
+      if (lzma->err != LZMA_OK)
+	 return -1;
+      size_t const n = sizeof(lzma->buffer)/sizeof(lzma->buffer[0]) - lzma->stream.avail_out;
+      size_t const m = (n == 0) ? 0 : fwrite(lzma->buffer, 1, n, lzma->file);
+      if (m != n)
+      {
+	 Res = -1;
+	 errno = 0;
+      }
+      else
+      {
+	 Res = Size - lzma->stream.avail_in;
+	 if (Res == 0)
+	 {
+	    // lzma run was okay, but produced no output…
+	    Res = -1;
+	    errno = EINTR;
+	 }
+      }
+      return Res;
+   }
+   virtual bool InternalWriteError() APT_OVERRIDE
+   {
+      return filefd->FileFdError("lzma_write: %s (%d)", _("Write error"), lzma->err);
+   }
+   virtual bool InternalStream() const APT_OVERRIDE { return true; }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      delete lzma;
+      lzma = nullptr;
+      return true;
+   }
+
+   explicit LzmaFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd), lzma(nullptr) {}
+   virtual ~LzmaFileFdPrivate() { InternalClose(""); }
+#endif
+};
+									/*}}}*/
+class APT_HIDDEN PipedFileFdPrivate: public FileFdPrivate				/*{{{*/
+/* if we don't have a specific class dealing with library calls, we (un)compress
+   by executing a specified binary and pipe in/out what we need */
+{
+public:
+   virtual bool InternalOpen(int const, unsigned int const Mode) APT_OVERRIDE
+   {
+      // collect zombies here in case we reopen
+      if (compressor_pid > 0)
+	 ExecWait(compressor_pid, "FileFdCompressor", true);
+
+      if ((Mode & FileFd::ReadWrite) == FileFd::ReadWrite)
+	 return filefd->FileFdError("ReadWrite mode is not supported for file %s", filefd->FileName.c_str());
+      if (compressor.Binary == "false")
+	 return filefd->FileFdError("libapt has inbuilt support for the %s compression,"
+	       " but was forced to ignore it in favor of an external binary – which isn't installed.", compressor.Name.c_str());
+
+      bool const Comp = (Mode & FileFd::WriteOnly) == FileFd::WriteOnly;
+      if (Comp == false && filefd->iFd != -1)
+      {
+	 // Handle 'decompression' of empty files
+	 struct stat Buf;
+	 if (fstat(filefd->iFd, &Buf) != 0)
+	    return filefd->FileFdErrno("fstat", "Could not stat fd %d for file %s", filefd->iFd, filefd->FileName.c_str());
+	 if (Buf.st_size == 0 && S_ISFIFO(Buf.st_mode) == false)
+	    return true;
+
+	 // We don't need the file open - instead let the compressor open it
+	 // as he properly knows better how to efficiently read from 'his' file
+	 if (filefd->FileName.empty() == false)
+	 {
+	    close(filefd->iFd);
+	    filefd->iFd = -1;
+	 }
+      }
+
+      // Create a data pipe
+      int Pipe[2] = {-1,-1};
+      if (pipe(Pipe) != 0)
+	 return filefd->FileFdErrno("pipe",_("Failed to create subprocess IPC"));
+      for (int J = 0; J != 2; J++)
+	 SetCloseExec(Pipe[J],true);
+
+      compressed_fd = filefd->iFd;
+      set_is_pipe(true);
+
+      if (Comp == true)
+	 filefd->iFd = Pipe[1];
+      else
+	 filefd->iFd = Pipe[0];
+
+      // The child..
+      compressor_pid = ExecFork();
+      if (compressor_pid == 0)
+      {
+	 if (Comp == true)
+	 {
+	    dup2(compressed_fd,STDOUT_FILENO);
+	    dup2(Pipe[0],STDIN_FILENO);
+	 }
+	 else
+	 {
+	    if (compressed_fd != -1)
+	       dup2(compressed_fd,STDIN_FILENO);
+	    dup2(Pipe[1],STDOUT_FILENO);
+	 }
+	 int const nullfd = open("/dev/null", O_WRONLY);
+	 if (nullfd != -1)
+	 {
+	    dup2(nullfd,STDERR_FILENO);
+	    close(nullfd);
+	 }
+
+	 SetCloseExec(STDOUT_FILENO,false);
+	 SetCloseExec(STDIN_FILENO,false);
+
+	 std::vector<char const*> Args;
+	 Args.push_back(compressor.Binary.c_str());
+	 std::vector<std::string> const * const addArgs =
+	    (Comp == true) ? &(compressor.CompressArgs) : &(compressor.UncompressArgs);
+	 for (std::vector<std::string>::const_iterator a = addArgs->begin();
+	       a != addArgs->end(); ++a)
+	    Args.push_back(a->c_str());
+	 if (Comp == false && filefd->FileName.empty() == false)
+	 {
+	    // commands not needing arguments, do not need to be told about using standard output
+	    // in reality, only testcases with tools like cat, rev, rot13, … are able to trigger this
+	    if (compressor.CompressArgs.empty() == false && compressor.UncompressArgs.empty() == false)
+	       Args.push_back("--stdout");
+	    if (filefd->TemporaryFileName.empty() == false)
+	       Args.push_back(filefd->TemporaryFileName.c_str());
+	    else
+	       Args.push_back(filefd->FileName.c_str());
+	 }
+	 Args.push_back(NULL);
+
+	 execvp(Args[0],(char **)&Args[0]);
+	 cerr << _("Failed to exec compressor ") << Args[0] << endl;
+	 _exit(100);
+      }
+      if (Comp == true)
+	 close(Pipe[0]);
+      else
+	 close(Pipe[1]);
+
+      return true;
+   }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return read(filefd->iFd, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      return write(filefd->iFd, From, Size);
+   }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE
+   {
+      bool Ret = true;
+      if (filefd->iFd != -1)
+      {
+	 close(filefd->iFd);
+	 filefd->iFd = -1;
+      }
+      if (compressor_pid > 0)
+	 Ret &= ExecWait(compressor_pid, "FileFdCompressor", true);
+      compressor_pid = -1;
+      return Ret;
+   }
+   explicit PipedFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
+   virtual ~PipedFileFdPrivate() { InternalClose(""); }
+};
+									/*}}}*/
+class APT_HIDDEN DirectFileFdPrivate: public FileFdPrivate				/*{{{*/
+{
+public:
+   virtual bool InternalOpen(int const, unsigned int const) APT_OVERRIDE { return true; }
+   virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) APT_OVERRIDE
+   {
+      return read(filefd->iFd, To, Size);
+   }
+   virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) APT_OVERRIDE
+   {
+      // files opened read+write are strange and only really "supported" for direct files
+      if (buffer.size() != 0)
+      {
+	 lseek(filefd->iFd, -buffer.size(), SEEK_CUR);
+	 buffer.reset();
+      }
+      return write(filefd->iFd, From, Size);
+   }
+   virtual bool InternalSeek(unsigned long long const To) APT_OVERRIDE
+   {
+      off_t const res = lseek(filefd->iFd, To, SEEK_SET);
+      if (res != (off_t)To)
+	 return filefd->FileFdError("Unable to seek to %llu", To);
+      seekpos = To;
+      buffer.reset();
+      return true;
+   }
+   virtual bool InternalSkip(unsigned long long Over) APT_OVERRIDE
+   {
+      if (Over >= buffer.size())
+      {
+	 Over -= buffer.size();
+	 buffer.reset();
+      }
+      else
+      {
+	 buffer.bufferstart += Over;
+	 return true;
+      }
+      if (Over == 0)
+	 return true;
+      off_t const res = lseek(filefd->iFd, Over, SEEK_CUR);
+      if (res < 0)
+	 return filefd->FileFdError("Unable to seek ahead %llu",Over);
+      seekpos = res;
+      return true;
+   }
+   virtual bool InternalTruncate(unsigned long long const To) APT_OVERRIDE
+   {
+      if (buffer.size() != 0)
+      {
+	 unsigned long long const seekpos = lseek(filefd->iFd, 0, SEEK_CUR);
+	 if ((seekpos - buffer.size()) >= To)
+	    buffer.reset();
+	 else if (seekpos >= To)
+	    buffer.bufferend = (To - seekpos) + buffer.bufferstart;
+	 else
+	    buffer.reset();
+      }
+      if (ftruncate(filefd->iFd, To) != 0)
+	 return filefd->FileFdError("Unable to truncate to %llu",To);
+      return true;
+   }
+   virtual unsigned long long InternalTell() APT_OVERRIDE
+   {
+      return lseek(filefd->iFd,0,SEEK_CUR) - buffer.size();
+   }
+   virtual unsigned long long InternalSize() APT_OVERRIDE
+   {
+      return filefd->FileSize();
+   }
+   virtual bool InternalClose(std::string const &) APT_OVERRIDE { return true; }
+   virtual bool InternalAlwaysAutoClose() const APT_OVERRIDE { return false; }
+
+   explicit DirectFileFdPrivate(FileFd * const filefd) : FileFdPrivate(filefd) {}
+   virtual ~DirectFileFdPrivate() { InternalClose(""); }
+};
+									/*}}}*/
+// FileFd Constructors							/*{{{*/
+FileFd::FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
+{
+   Open(FileName,Mode, None, AccessMode);
+}
+FileFd::FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL)
+{
+   Open(FileName,Mode, Compress, AccessMode);
+}
+FileFd::FileFd() : iFd(-1), Flags(AutoClose), d(NULL) {}
+FileFd::FileFd(int const Fd, unsigned int const Mode, CompressMode Compress) : iFd(-1), Flags(0), d(NULL)
+{
+   OpenDescriptor(Fd, Mode, Compress);
+}
+FileFd::FileFd(int const Fd, bool const AutoClose) : iFd(-1), Flags(0), d(NULL)
+{
+   OpenDescriptor(Fd, ReadWrite, None, AutoClose);
+}
+									/*}}}*/
+// FileFd::Open - Open a file						/*{{{*/
+// ---------------------------------------------------------------------
+/* The most commonly used open mode combinations are given with Mode */
+bool FileFd::Open(string FileName,unsigned int const Mode,CompressMode Compress, unsigned long const AccessMode)
+{
+   if (Mode == ReadOnlyGzip)
+      return Open(FileName, ReadOnly, Gzip, AccessMode);
+
+   if (Compress == Auto && (Mode & WriteOnly) == WriteOnly)
+      return FileFdError("Autodetection on %s only works in ReadOnly openmode!", FileName.c_str());
+
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   if (Compress == Auto)
+   {
+      for (; compressor != compressors.end(); ++compressor)
+      {
+	 std::string file = FileName + compressor->Extension;
+	 if (FileExists(file) == false)
+	    continue;
+	 FileName = file;
+	 break;
+      }
+   }
+   else if (Compress == Extension)
+   {
+      std::string::size_type const found = FileName.find_last_of('.');
+      std::string ext;
+      if (found != std::string::npos)
+      {
+	 ext = FileName.substr(found);
+	 if (ext == ".new" || ext == ".bak")
+	 {
+	    std::string::size_type const found2 = FileName.find_last_of('.', found - 1);
+	    if (found2 != std::string::npos)
+	       ext = FileName.substr(found2, found - found2);
+	    else
+	       ext.clear();
+	 }
+      }
+      for (; compressor != compressors.end(); ++compressor)
+	 if (ext == compressor->Extension)
+	    break;
+      // no matching extension - assume uncompressed (imagine files like 'example.org_Packages')
+      if (compressor == compressors.end())
+	 for (compressor = compressors.begin(); compressor != compressors.end(); ++compressor)
+	    if (compressor->Name == ".")
+	       break;
+   }
+   else
+   {
+      std::string name;
+      switch (Compress)
+      {
+      case None: name = "."; break;
+      case Gzip: name = "gzip"; break;
+      case Bzip2: name = "bzip2"; break;
+      case Lzma: name = "lzma"; break;
+      case Xz: name = "xz"; break;
+      case Lz4: name = "lz4"; break;
+      case Zstd: name = "zstd"; break;
+      case Auto:
+      case Extension:
+	 // Unreachable
+	 return FileFdError("Opening File %s in None, Auto or Extension should be already handled?!?", FileName.c_str());
+      }
+      for (; compressor != compressors.end(); ++compressor)
+	 if (compressor->Name == name)
+	    break;
+      if (compressor == compressors.end())
+	 return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
+   }
+
+   if (compressor == compressors.end())
+      return FileFdError("Can't find a match for specified compressor mode for file %s", FileName.c_str());
+   return Open(FileName, Mode, *compressor, AccessMode);
+}
+bool FileFd::Open(string FileName,unsigned int const Mode,APT::Configuration::Compressor const &compressor, unsigned long const AccessMode)
+{
+   Close();
+   Flags = AutoClose;
+
+   if ((Mode & WriteOnly) != WriteOnly && (Mode & (Atomic | Create | Empty | Exclusive)) != 0)
+      return FileFdError("ReadOnly mode for %s doesn't accept additional flags!", FileName.c_str());
+   if ((Mode & ReadWrite) == 0)
+      return FileFdError("No openmode provided in FileFd::Open for %s", FileName.c_str());
+
+   unsigned int OpenMode = Mode;
+   if (FileName == "/dev/null")
+      OpenMode = OpenMode & ~(Atomic | Exclusive | Create | Empty);
+
+   if ((OpenMode & Atomic) == Atomic)
+   {
+      Flags |= Replace;
+   }
+   else if ((OpenMode & (Exclusive | Create)) == (Exclusive | Create))
+   {
+      // for atomic, this will be done by rename in Close()
+      RemoveFile("FileFd::Open", FileName);
+   }
+   if ((OpenMode & Empty) == Empty)
+   {
+      struct stat Buf;
+      if (lstat(FileName.c_str(),&Buf) == 0 && S_ISLNK(Buf.st_mode))
+	 RemoveFile("FileFd::Open", FileName);
+   }
+
+   int fileflags = 0;
+   #define if_FLAGGED_SET(FLAG, MODE) if ((OpenMode & FLAG) == FLAG) fileflags |= MODE
+   if_FLAGGED_SET(ReadWrite, O_RDWR);
+   else if_FLAGGED_SET(ReadOnly, O_RDONLY);
+   else if_FLAGGED_SET(WriteOnly, O_WRONLY);
+
+   if_FLAGGED_SET(Create, O_CREAT);
+   if_FLAGGED_SET(Empty, O_TRUNC);
+   if_FLAGGED_SET(Exclusive, O_EXCL);
+   #undef if_FLAGGED_SET
+
+   if ((OpenMode & Atomic) == Atomic)
+   {
+      char *name = strdup((FileName + ".XXXXXX").c_str());
+
+      if((iFd = mkstemp(name)) == -1)
+      {
+          free(name);
+          return FileFdErrno("mkstemp", "Could not create temporary file for %s", FileName.c_str());
+      }
+
+      TemporaryFileName = string(name);
+      free(name);
+
+      // umask() will always set the umask and return the previous value, so
+      // we first set the umask and then reset it to the old value
+      mode_t const CurrentUmask = umask(0);
+      umask(CurrentUmask);
+      // calculate the actual file permissions (just like open/creat)
+      mode_t const FilePermissions = (AccessMode & ~CurrentUmask);
+
+      if(fchmod(iFd, FilePermissions) == -1)
+          return FileFdErrno("fchmod", "Could not change permissions for temporary file %s", TemporaryFileName.c_str());
+   }
+   else
+      iFd = open(FileName.c_str(), fileflags, AccessMode);
+
+   this->FileName = FileName;
+   if (iFd == -1 || OpenInternDescriptor(OpenMode, compressor) == false)
+   {
+      if (iFd != -1)
+      {
+	 close (iFd);
+	 iFd = -1;
+      }
+      return FileFdErrno("open",_("Could not open file %s"), FileName.c_str());
+   }
+
+   SetCloseExec(iFd,true);
+   return true;
+}
+									/*}}}*/
+// FileFd::OpenDescriptor - Open a filedescriptor			/*{{{*/
+bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, CompressMode Compress, bool AutoClose)
+{
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   std::string name;
+
+   // compat with the old API
+   if (Mode == ReadOnlyGzip && Compress == None)
+      Compress = Gzip;
+
+   switch (Compress)
+   {
+   case None: name = "."; break;
+   case Gzip: name = "gzip"; break;
+   case Bzip2: name = "bzip2"; break;
+   case Lzma: name = "lzma"; break;
+   case Xz: name = "xz"; break;
+   case Lz4: name = "lz4"; break;
+   case Zstd: name = "zstd"; break;
+   case Auto:
+   case Extension:
+      if (AutoClose == true && Fd != -1)
+	 close(Fd);
+      return FileFdError("Opening Fd %d in Auto or Extension compression mode is not supported", Fd);
+   }
+   for (; compressor != compressors.end(); ++compressor)
+      if (compressor->Name == name)
+	 break;
+   if (compressor == compressors.end())
+   {
+      if (AutoClose == true && Fd != -1)
+	 close(Fd);
+      return FileFdError("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
+   }
+   return OpenDescriptor(Fd, Mode, *compressor, AutoClose);
+}
+bool FileFd::OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration::Compressor const &compressor, bool AutoClose)
+{
+   Close();
+   Flags = (AutoClose) ? FileFd::AutoClose : 0;
+   iFd = Fd;
+   this->FileName = "";
+   if (OpenInternDescriptor(Mode, compressor) == false)
+   {
+      if (iFd != -1 && (
+	(Flags & Compressed) == Compressed ||
+	AutoClose == true))
+      {
+	 close (iFd);
+	 iFd = -1;
+      }
+      return FileFdError(_("Could not open file descriptor %d"), Fd);
+   }
+   return true;
+}
+bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor)
+{
+   if (iFd == -1)
+      return false;
+
+   if (d != nullptr)
+      d->InternalClose(FileName);
+
+   if (d == nullptr)
+   {
+      if (false)
+	 /* dummy so that the rest can be 'else if's */;
+#define APT_COMPRESS_INIT(NAME, CONSTRUCTOR) \
+      else if (compressor.Name == NAME) \
+	 d = new CONSTRUCTOR(this)
+#ifdef HAVE_ZLIB
+      APT_COMPRESS_INIT("gzip", GzipFileFdPrivate);
+#endif
+#ifdef HAVE_BZ2
+      APT_COMPRESS_INIT("bzip2", Bz2FileFdPrivate);
+#endif
+#ifdef HAVE_LZMA
+      APT_COMPRESS_INIT("xz", LzmaFileFdPrivate);
+      APT_COMPRESS_INIT("lzma", LzmaFileFdPrivate);
+#endif
+#ifdef HAVE_LZ4
+      APT_COMPRESS_INIT("lz4", Lz4FileFdPrivate);
+#endif
+#ifdef HAVE_ZSTD
+      APT_COMPRESS_INIT("zstd", ZstdFileFdPrivate);
+#endif
+#undef APT_COMPRESS_INIT
+      else if (compressor.Name == "." || compressor.Binary.empty() == true)
+	 d = new DirectFileFdPrivate(this);
+      else
+	 d = new PipedFileFdPrivate(this);
+
+      if (Mode & BufferedWrite)
+	 d = new BufferedWriteFileFdPrivate(d);
+
+      d->set_openmode(Mode);
+      d->set_compressor(compressor);
+      if ((Flags & AutoClose) != AutoClose && d->InternalAlwaysAutoClose())
+      {
+	 // Need to duplicate fd here or gz/bz2 close for cleanup will close the fd as well
+	 int const internFd = dup(iFd);
+	 if (internFd == -1)
+	    return FileFdErrno("OpenInternDescriptor", _("Could not open file descriptor %d"), iFd);
+	 iFd = internFd;
+      }
+   }
+   return d->InternalOpen(iFd, Mode);
+}
+									/*}}}*/
+// FileFd::~File - Closes the file					/*{{{*/
+// ---------------------------------------------------------------------
+/* If the proper modes are selected then we close the Fd and possibly
+   unlink the file on error. */
+FileFd::~FileFd()
+{
+   Close();
+   if (d != NULL)
+      d->InternalClose(FileName);
+   delete d;
+   d = NULL;
+}
+									/*}}}*/
+// FileFd::Read - Read a bit of the file				/*{{{*/
+// ---------------------------------------------------------------------
+/* We are careful to handle interruption by a signal while reading
+   gracefully. */
+bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
+{
+   if (d == nullptr || Failed())
+      return false;
+   ssize_t Res = 1;
+   errno = 0;
+   if (Actual != 0)
+      *Actual = 0;
+   *((char *)To) = '\0';
+   while (Res > 0 && Size > 0)
+   {
+      Res = d->InternalRead(To, Size);
+
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    // trick the while-loop into running again
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return d->InternalReadError();
+      }
+      
+      To = (char *)To + Res;
+      Size -= Res;
+      if (d != NULL)
+	 d->set_seekpos(d->get_seekpos() + Res);
+      if (Actual != 0)
+	 *Actual += Res;
+   }
+   
+   if (Size == 0)
+      return true;
+   
+   // Eof handling
+   if (Actual != 0)
+   {
+      Flags |= HitEof;
+      return true;
+   }
+
+   return FileFdError(_("read, still have %llu to read but none left"), Size);
+}
+bool FileFd::Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual)
+{
+   ssize_t Res = 1;
+   errno = 0;
+   if (Actual != nullptr)
+      *Actual = 0;
+   *static_cast<char *>(To) = '\0';
+   while (Res > 0 && Size > 0)
+   {
+      Res = read(Fd, To, Size);
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return _error->Errno("read", _("Read error"));
+      }
+      To = static_cast<char *>(To) + Res;
+      Size -= Res;
+      if (Actual != 0)
+	 *Actual += Res;
+   }
+   if (Size == 0)
+      return true;
+   if (Actual != nullptr)
+      return true;
+   return _error->Error(_("read, still have %llu to read but none left"), Size);
+}
+									/*}}}*/
+// FileFd::ReadLine - Read a complete line from the file		/*{{{*/
+char* FileFd::ReadLine(char *To, unsigned long long const Size)
+{
+   *To = '\0';
+   if (d == nullptr || Failed())
+      return nullptr;
+   return d->InternalReadLine(To, Size);
+}
+bool FileFd::ReadLine(std::string &To)
+{
+   To.clear();
+   if (d == nullptr || Failed())
+      return false;
+   constexpr size_t buflen = 4096;
+   char buffer[buflen];
+   size_t len;
+   do
+   {
+      if (d->InternalReadLine(buffer, buflen) == nullptr)
+	 return false;
+      len = strlen(buffer);
+      To.append(buffer, len);
+   } while (len == buflen - 1 && buffer[len - 2] != '\n');
+   // remove the newline at the end
+   auto const i = To.find_last_not_of("\r\n");
+   if (i == std::string::npos)
+      To.clear();
+   else
+      To.erase(i + 1);
+   return true;
+}
+									/*}}}*/
+// FileFd::Flush - Flush the file  					/*{{{*/
+bool FileFd::Flush()
+{
+   if (Failed())
+      return false;
+   if (d == nullptr)
+      return true;
+
+   return d->InternalFlush();
+}
+									/*}}}*/
+// FileFd::Write - Write to the file					/*{{{*/
+bool FileFd::Write(const void *From,unsigned long long Size)
+{
+   if (d == nullptr || Failed())
+      return false;
+   ssize_t Res = 1;
+   errno = 0;
+   while (Res > 0 && Size > 0)
+   {
+      Res = d->InternalWrite(From, Size);
+
+      if (Res < 0)
+      {
+	 if (errno == EINTR)
+	 {
+	    // trick the while-loop into running again
+	    Res = 1;
+	    errno = 0;
+	    continue;
+	 }
+	 return d->InternalWriteError();
+      }
+
+      From = (char const *)From + Res;
+      Size -= Res;
+      if (d != NULL)
+	 d->set_seekpos(d->get_seekpos() + Res);
+   }
+
+   if (Size == 0)
+      return true;
+
+   return FileFdError(_("write, still have %llu to write but couldn't"), Size);
+}
+bool FileFd::Write(int Fd, const void *From, unsigned long long Size)
+{
+   ssize_t Res = 1;
+   errno = 0;
+   while (Res > 0 && Size > 0)
+   {
+      Res = write(Fd,From,Size);
+      if (Res < 0 && errno == EINTR)
+	 continue;
+      if (Res < 0)
+	 return _error->Errno("write",_("Write error"));
+
+      From = (char const *)From + Res;
+      Size -= Res;
+   }
+
+   if (Size == 0)
+      return true;
+
+   return _error->Error(_("write, still have %llu to write but couldn't"), Size);
+}
+									/*}}}*/
+// FileFd::Seek - Seek in the file					/*{{{*/
+bool FileFd::Seek(unsigned long long To)
+{
+   if (d == nullptr || Failed())
+      return false;
+   Flags &= ~HitEof;
+   return d->InternalSeek(To);
+}
+									/*}}}*/
+// FileFd::Skip - Skip over data in the file				/*{{{*/
+bool FileFd::Skip(unsigned long long Over)
+{
+   if (d == nullptr || Failed())
+      return false;
+   return d->InternalSkip(Over);
+}
+									/*}}}*/
+// FileFd::Truncate - Truncate the file					/*{{{*/
+bool FileFd::Truncate(unsigned long long To)
+{
+   if (d == nullptr || Failed())
+      return false;
+   // truncating /dev/null is always successful - as we get an error otherwise
+   if (To == 0 && FileName == "/dev/null")
+      return true;
+   return d->InternalTruncate(To);
+}
+									/*}}}*/
+// FileFd::Tell - Current seek position					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned long long FileFd::Tell()
+{
+   if (d == nullptr || Failed())
+      return false;
+   off_t const Res = d->InternalTell();
+   if (Res == (off_t)-1)
+      FileFdErrno("lseek","Failed to determine the current file position");
+   d->set_seekpos(Res);
+   return Res;
+}
+									/*}}}*/
+static bool StatFileFd(char const * const msg, int const iFd, std::string const &FileName, struct stat &Buf, FileFdPrivate * const d) /*{{{*/
+{
+   bool ispipe = (d != NULL && d->get_is_pipe() == true);
+   if (ispipe == false)
+   {
+      if (fstat(iFd,&Buf) != 0)
+	 // higher-level code will generate more meaningful messages,
+	 // even translated this would be meaningless for users
+	 return _error->Errno("fstat", "Unable to determine %s for fd %i", msg, iFd);
+      if (FileName.empty() == false)
+	 ispipe = S_ISFIFO(Buf.st_mode);
+   }
+
+   // for compressor pipes st_size is undefined and at 'best' zero
+   if (ispipe == true)
+   {
+      // we set it here, too, as we get the info here for free
+      // in theory the Open-methods should take care of it already
+      if (d != NULL)
+	 d->set_is_pipe(true);
+      if (stat(FileName.c_str(), &Buf) != 0)
+	 return _error->Errno("fstat", "Unable to determine %s for file %s", msg, FileName.c_str());
+   }
+   return true;
+}
+									/*}}}*/
+// FileFd::FileSize - Return the size of the file			/*{{{*/
+unsigned long long FileFd::FileSize()
+{
+   struct stat Buf;
+   if (StatFileFd("file size", iFd, FileName, Buf, d) == false)
+   {
+      Flags |= Fail;
+      return 0;
+   }
+   return Buf.st_size;
+}
+									/*}}}*/
+// FileFd::ModificationTime - Return the time of last touch		/*{{{*/
+time_t FileFd::ModificationTime()
+{
+   struct stat Buf;
+   if (StatFileFd("modification time", iFd, FileName, Buf, d) == false)
+   {
+      Flags |= Fail;
+      return 0;
+   }
+   return Buf.st_mtime;
+}
+									/*}}}*/
+// FileFd::Size - Return the size of the content in the file		/*{{{*/
+unsigned long long FileFd::Size()
+{
+   if (d == nullptr)
+      return 0;
+   return d->InternalSize();
+}
+									/*}}}*/
+// FileFd::Close - Close the file if the close flag is set		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FileFd::Close()
+{
+   if (Failed() == false && Flush() == false)
+      return false;
+   if (iFd == -1)
+      return true;
+
+   bool Res = true;
+   if ((Flags & AutoClose) == AutoClose)
+   {
+      if ((Flags & Compressed) != Compressed && iFd > 0 && close(iFd) != 0)
+	 Res &= _error->Errno("close",_("Problem closing the file %s"), FileName.c_str());
+   }
+
+   if (d != NULL)
+   {
+      Res &= d->InternalClose(FileName);
+      delete d;
+      d = NULL;
+   }
+
+   if ((Flags & Replace) == Replace) {
+      if (Failed() == false && rename(TemporaryFileName.c_str(), FileName.c_str()) != 0)
+	 Res &= _error->Errno("rename",_("Problem renaming the file %s to %s"), TemporaryFileName.c_str(), FileName.c_str());
+
+      FileName = TemporaryFileName; // for the unlink() below.
+      TemporaryFileName.clear();
+   }
+
+   iFd = -1;
+
+   if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
+       FileName.empty() == false)
+      Res &= RemoveFile("FileFd::Close", FileName);
+
+   if (Res == false)
+      Flags |= Fail;
+   return Res;
+}
+									/*}}}*/
+// FileFd::Sync - Sync the file						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FileFd::Sync()
+{
+   if (fsync(iFd) != 0)
+      return FileFdErrno("sync",_("Problem syncing the file"));
+   return true;
+}
+									/*}}}*/
+// FileFd::FileFdErrno - set Fail and call _error->Errno		*{{{*/
+bool FileFd::FileFdErrno(const char *Function, const char *Description,...)
+{
+   Flags |= Fail;
+   va_list args;
+   size_t msgSize = 400;
+   int const errsv = errno;
+   bool retry;
+   do {
+      va_start(args,Description);
+      retry = _error->InsertErrno(GlobalError::ERROR, Function, Description, args, errsv, msgSize);
+      va_end(args);
+   } while (retry);
+   return false;
+}
+									/*}}}*/
+// FileFd::FileFdError - set Fail and call _error->Error		*{{{*/
+bool FileFd::FileFdError(const char *Description,...) {
+   Flags |= Fail;
+   va_list args;
+   size_t msgSize = 400;
+   bool retry;
+   do {
+      va_start(args,Description);
+      retry = _error->Insert(GlobalError::ERROR, Description, args, msgSize);
+      va_end(args);
+   } while (retry);
+   return false;
+}
+									/*}}}*/
+// Glob - wrapper around "glob()"					/*{{{*/
+std::vector<std::string> Glob(std::string const &pattern, int flags)
+{
+   std::vector<std::string> result;
+   glob_t globbuf;
+   int glob_res;
+   unsigned int i;
+
+   glob_res = glob(pattern.c_str(),  flags, NULL, &globbuf);
+
+   if (glob_res != 0)
+   {
+      if(glob_res != GLOB_NOMATCH) {
+         _error->Errno("glob", "Problem with glob");
+         return result;
+      }
+   }
+
+   // append results
+   for(i=0;i<globbuf.gl_pathc;i++)
+      result.push_back(string(globbuf.gl_pathv[i]));
+
+   globfree(&globbuf);
+   return result;
+}
+									/*}}}*/
+static std::string APT_NONNULL(1) GetTempDirEnv(char const * const env)	/*{{{*/
+{
+   const char *tmpdir = getenv(env);
+
+#ifdef P_tmpdir
+   if (!tmpdir)
+      tmpdir = P_tmpdir;
+#endif
+
+   struct stat st;
+   if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set
+	 stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0) // exists and is directory
+      tmpdir = "/tmp";
+   else if (geteuid() != 0 && // root can do everything anyway
+	 faccessat(AT_FDCWD, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS) != 0) // current user has rwx access to directory
+      tmpdir = "/tmp";
+
+   return string(tmpdir);
+}
+									/*}}}*/
+std::string GetTempDir()						/*{{{*/
+{
+   return GetTempDirEnv("TMPDIR");
+}
+std::string GetTempDir(std::string const &User)
+{
+   // no need/possibility to drop privs
+   if(getuid() != 0 || User.empty() || User == "root")
+      return GetTempDir();
+
+   struct passwd const * const pw = getpwnam(User.c_str());
+   if (pw == NULL)
+      return GetTempDir();
+
+   gid_t const old_euid = geteuid();
+   gid_t const old_egid = getegid();
+   if (setegid(pw->pw_gid) != 0)
+      _error->Errno("setegid", "setegid %u failed", pw->pw_gid);
+   if (seteuid(pw->pw_uid) != 0)
+      _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid);
+
+   std::string const tmp = GetTempDir();
+
+   if (seteuid(old_euid) != 0)
+      _error->Errno("seteuid", "seteuid %u failed", old_euid);
+   if (setegid(old_egid) != 0)
+      _error->Errno("setegid", "setegid %u failed", old_egid);
+
+   return tmp;
+}
+									/*}}}*/
+FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd)	/*{{{*/
+{
+   return GetTempFile(Prefix, ImmediateUnlink, TmpFd, false);
+}
+FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd, bool Buffered)
+{
+   std::string fn;
+   std::string const tempdir = GetTempDir();
+   int fd = -1;
+#ifdef O_TMPFILE
+   if (ImmediateUnlink)
+      fd = open(tempdir.c_str(), O_RDWR|O_TMPFILE|O_EXCL|O_CLOEXEC, 0600);
+   if (fd < 0)
+#endif
+   {
+      auto const suffix = Prefix.find(".XXXXXX.");
+      std::vector<char> buffer(tempdir.length() + 1 + Prefix.length() + (suffix == std::string::npos ? 7 : 0) + 1, '\0');
+      if (suffix != std::string::npos)
+      {
+	 if (snprintf(buffer.data(), buffer.size(), "%s/%s", tempdir.c_str(), Prefix.c_str()) > 0)
+	 {
+	    ssize_t const suffixlen = (buffer.size() - 1) - (tempdir.length() + 1 + suffix + 7);
+	    if (likely(suffixlen > 0))
+	       fd = mkstemps(buffer.data(), suffixlen);
+	 }
+      }
+      else
+      {
+	 if (snprintf(buffer.data(), buffer.size(), "%s/%s.XXXXXX", tempdir.c_str(), Prefix.c_str()) > 0)
+	    fd = mkstemp(buffer.data());
+      }
+      fn.assign(buffer.data(), buffer.size() - 1);
+      if (ImmediateUnlink && fd != -1)
+	 unlink(fn.c_str());
+   }
+   if (fd < 0)
+   {
+      _error->Errno("GetTempFile",_("Unable to mkstemp %s"), fn.c_str());
+      return nullptr;
+   }
+   FileFd * const Fd = TmpFd == nullptr ? new FileFd() : TmpFd;
+   if (not Fd->OpenDescriptor(fd, FileFd::ReadWrite | (Buffered ? FileFd::BufferedWrite : 0), FileFd::None, true))
+   {
+      _error->Errno("GetTempFile",_("Unable to write to %s"),fn.c_str());
+      if (TmpFd == nullptr)
+	 delete Fd;
+      return nullptr;
+   }
+   if (not ImmediateUnlink)
+      Fd->SetFileName(fn);
+   return Fd;
+}
+									/*}}}*/
+bool Rename(std::string From, std::string To)				/*{{{*/
+{
+   if (rename(From.c_str(),To.c_str()) != 0)
+   {
+      _error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
+                    From.c_str(),To.c_str());
+      return false;
+   }
+   return true;
+}
+									/*}}}*/
+bool Popen(const char *Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode, bool CaptureStderr, bool Sandbox) /*{{{*/
+{
+   int fd;
+   if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)
+      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
+
+   int Pipe[2] = {-1, -1};
+   if(pipe(Pipe) != 0)
+      return _error->Errno("pipe", _("Failed to create subprocess IPC"));
+
+   std::set<int> keep_fds;
+   keep_fds.insert(Pipe[0]);
+   keep_fds.insert(Pipe[1]);
+   Child = ExecFork(keep_fds);
+   if(Child < 0)
+      return _error->Errno("fork", "Failed to fork");
+   if(Child == 0)
+   {
+      if (Sandbox && (getuid() == 0 || geteuid() == 0) && !DropPrivileges())
+      {
+	 _error->DumpErrors();
+	 _exit(1);
+      }
+      if(Mode == FileFd::ReadOnly)
+      {
+         close(Pipe[0]);
+         fd = Pipe[1];
+      }
+      else if(Mode == FileFd::WriteOnly)
+      {
+         close(Pipe[1]);
+         fd = Pipe[0];
+      }
+
+      if(Mode == FileFd::ReadOnly)
+      {
+         dup2(fd, 1);
+	 if (CaptureStderr == true)
+	    dup2(fd, 2);
+      } else if(Mode == FileFd::WriteOnly)
+         dup2(fd, 0);
+
+      execv(Args[0], (char**)Args);
+      _exit(100);
+   }
+   if(Mode == FileFd::ReadOnly)
+   {
+      close(Pipe[1]);
+      fd = Pipe[0];
+   }
+   else if(Mode == FileFd::WriteOnly)
+   {
+      close(Pipe[0]);
+      fd = Pipe[1];
+   }
+   else
+      return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
+   Fd.OpenDescriptor(fd, Mode, FileFd::None, true);
+
+   return true;
+}
+									/*}}}*/
+bool DropPrivileges()							/*{{{*/
+{
+   if(_config->FindB("Debug::NoDropPrivs", false) == true)
+      return true;
+
+#if __gnu_linux__
+#if defined(PR_SET_NO_NEW_PRIVS) && ( PR_SET_NO_NEW_PRIVS != 38 )
+#error "PR_SET_NO_NEW_PRIVS is defined, but with a different value than expected!"
+#endif
+   // see prctl(2), needs linux3.5 at runtime - magic constant to avoid it at buildtime
+   int ret = prctl(38, 1, 0, 0, 0);
+   // ignore EINVAL - kernel is too old to understand the option
+   if(ret < 0 && errno != EINVAL)
+      _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret);
+#endif
+
+   // empty setting disables privilege dropping - this also ensures
+   // backward compatibility, see bug #764506
+   const std::string toUser = _config->Find("APT::Sandbox::User");
+   if (toUser.empty() || toUser == "root")
+      return true;
+
+   // a lot can go wrong trying to drop privileges completely,
+   // so ideally we would like to verify that we have done it –
+   // but the verify asks for too much in case of fakeroot (and alike)
+   // [Specific checks can be overridden with dedicated options]
+   bool const VerifySandboxing = _config->FindB("APT::Sandbox::Verify", false);
+
+   // uid will be 0 in the end, but gid might be different anyway
+   uid_t const old_uid = getuid();
+   gid_t const old_gid = getgid();
+
+   if (old_uid != 0)
+      return true;
+
+   struct passwd *pw = getpwnam(toUser.c_str());
+   if (pw == NULL)
+      return _error->Error("No user %s, can not drop rights", toUser.c_str());
+
+   // Do not change the order here, it might break things
+   // Get rid of all our supplementary groups first
+   if (setgroups(1, &pw->pw_gid))
+      return _error->Errno("setgroups", "Failed to setgroups");
+
+   // Now change the group ids to the new user
+#ifdef HAVE_SETRESGID
+   if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
+      return _error->Errno("setresgid", "Failed to set new group ids");
+#else
+   if (setegid(pw->pw_gid) != 0)
+      return _error->Errno("setegid", "Failed to setegid");
+
+   if (setgid(pw->pw_gid) != 0)
+      return _error->Errno("setgid", "Failed to setgid");
+#endif
+
+   // Change the user ids to the new user
+#ifdef HAVE_SETRESUID
+   if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
+      return _error->Errno("setresuid", "Failed to set new user ids");
+#else
+   if (setuid(pw->pw_uid) != 0)
+      return _error->Errno("setuid", "Failed to setuid");
+   if (seteuid(pw->pw_uid) != 0)
+      return _error->Errno("seteuid", "Failed to seteuid");
+#endif
+
+   // disabled by default as fakeroot doesn't implement getgroups currently (#806521)
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Groups", false) == true)
+   {
+      // Verify that the user isn't still in any supplementary groups
+      long const ngroups_max = sysconf(_SC_NGROUPS_MAX);
+      std::unique_ptr<gid_t[]> gidlist(new gid_t[ngroups_max]);
+      if (unlikely(gidlist == NULL))
+	 return _error->Error("Allocation of a list of size %lu for getgroups failed", ngroups_max);
+      ssize_t gidlist_nr;
+      if ((gidlist_nr = getgroups(ngroups_max, gidlist.get())) < 0)
+	 return _error->Errno("getgroups", "Could not get new groups (%lu)", ngroups_max);
+      for (ssize_t i = 0; i < gidlist_nr; ++i)
+	 if (gidlist[i] != pw->pw_gid)
+	    return _error->Error("Could not switch group, user %s is still in group %d", toUser.c_str(), gidlist[i]);
+   }
+
+   // enabled by default as all fakeroot-lookalikes should fake that accordingly
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::IDs", true) == true)
+   {
+      // Verify that gid, egid, uid, and euid changed
+      if (getgid() != pw->pw_gid)
+	 return _error->Error("Could not switch group");
+      if (getegid() != pw->pw_gid)
+	 return _error->Error("Could not switch effective group");
+      if (getuid() != pw->pw_uid)
+	 return _error->Error("Could not switch user");
+      if (geteuid() != pw->pw_uid)
+	 return _error->Error("Could not switch effective user");
+
+#ifdef HAVE_GETRESUID
+      // verify that the saved set-user-id was changed as well
+      uid_t ruid = 0;
+      uid_t euid = 0;
+      uid_t suid = 0;
+      if (getresuid(&ruid, &euid, &suid))
+	 return _error->Errno("getresuid", "Could not get saved set-user-ID");
+      if (suid != pw->pw_uid)
+	 return _error->Error("Could not switch saved set-user-ID");
+#endif
+
+#ifdef HAVE_GETRESGID
+      // verify that the saved set-group-id was changed as well
+      gid_t rgid = 0;
+      gid_t egid = 0;
+      gid_t sgid = 0;
+      if (getresgid(&rgid, &egid, &sgid))
+	 return _error->Errno("getresuid", "Could not get saved set-group-ID");
+      if (sgid != pw->pw_gid)
+	 return _error->Error("Could not switch saved set-group-ID");
+#endif
+   }
+
+   // disabled as fakeroot doesn't forbid (by design) (re)gaining root from unprivileged
+   if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Regain", false) == true)
+   {
+      // Check that uid and gid changes do not work anymore
+      if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1))
+	 return _error->Error("Could restore a gid to root, privilege dropping did not work");
+
+      if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1))
+	 return _error->Error("Could restore a uid to root, privilege dropping did not work");
+   }
+
+   if (_config->FindB("APT::Sandbox::ResetEnvironment", true))
+   {
+      setenv("HOME", pw->pw_dir, 1);
+      setenv("USER", pw->pw_name, 1);
+      setenv("USERNAME", pw->pw_name, 1);
+      setenv("LOGNAME", pw->pw_name, 1);
+      auto const shell = flNotDir(pw->pw_shell);
+      if (shell == "false" || shell == "nologin")
+	 setenv("SHELL", "/bin/sh", 1);
+      else
+	 setenv("SHELL", pw->pw_shell, 1);
+      auto const apt_setenv_tmp = [](char const * const env) {
+	 auto const tmpdir = getenv(env);
+	 if (tmpdir != nullptr)
+	 {
+	    auto const ourtmpdir = GetTempDirEnv(env);
+	    if (ourtmpdir != tmpdir)
+	       setenv(env, ourtmpdir.c_str(), 1);
+	 }
+      };
+      apt_setenv_tmp("TMPDIR");
+      apt_setenv_tmp("TEMPDIR");
+      apt_setenv_tmp("TMP");
+      apt_setenv_tmp("TEMP");
+   }
+
+   return true;
+}
+									/*}}}*/
+bool OpenConfigurationFileFd(std::string const &File, FileFd &Fd) /*{{{*/
+{
+   int const fd = open(File.c_str(), O_RDONLY | O_CLOEXEC | O_NOCTTY);
+   if (fd == -1)
+      return _error->WarningE("open", _("Unable to read %s"), File.c_str());
+   APT::Configuration::Compressor none(".", "", "", nullptr, nullptr, 0);
+   if (Fd.OpenDescriptor(fd, FileFd::ReadOnly, none, true) == false)
+      return false;
+   Fd.SetFileName(File);
+   return true;
+}
+									/*}}}*/
+int Inhibit(const char *what, const char *who, const char *why, const char *mode) /*{{{*/
+{
+#ifdef HAVE_SYSTEMD
+   sd_bus_error error = SD_BUS_ERROR_NULL;
+   sd_bus_message *m = NULL;
+   sd_bus *bus = NULL;
+   int fd;
+   int r;
+
+   r = sd_bus_open_system(&bus);
+   if (r < 0)
+      goto out;
+
+   r = sd_bus_call_method(bus,
+			  "org.freedesktop.login1",
+			  "/org/freedesktop/login1",
+			  "org.freedesktop.login1.Manager",
+			  "Inhibit",
+			  &error,
+			  &m,
+			  "ssss",
+			  what,
+			  who,
+			  why,
+			  mode);
+   if (r < 0)
+      goto out;
+
+   r = sd_bus_message_read(m, "h", &fd);
+   if (r < 0)
+      goto out;
+
+   // We received a file descriptor, return it - systemd will close the read fd
+   // on free, so let's duplicate it here.
+   r = dup(fd);
+out:
+   sd_bus_error_free(&error);
+   sd_bus_message_unref(m);
+   sd_bus_unref(bus);
+   return r;
+#else
+   return -ENOTSUP;
+#endif
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/fileutl.h b/apt-pkg/contrib/fileutl.h
new file mode 100644
index 0000000..970b118
--- /dev/null
+++ b/apt-pkg/contrib/fileutl.h
@@ -0,0 +1,287 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   File Utilities
+   
+   CopyFile - Buffered copy of a single file
+   GetLock - dpkg compatible lock file manipulation (fcntl)
+   FileExists - Returns true if the file exists
+   SafeGetCWD - Returns the CWD in a string with overrun protection 
+   
+   The file class is a handy abstraction for various functions+classes
+   that need to accept filenames.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_FILEUTL_H
+#define PKGLIB_FILEUTL_H
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/macros.h>
+
+#include <set>
+#include <string>
+#include <vector>
+#include <sys/stat.h>
+#include <time.h>
+
+/* Define this for python-apt */
+#define APT_HAS_GZIP 1
+
+class FileFdPrivate;
+class APT_PUBLIC FileFd
+{
+   friend class FileFdPrivate;
+   friend class GzipFileFdPrivate;
+   friend class Bz2FileFdPrivate;
+   friend class LzmaFileFdPrivate;
+   friend class Lz4FileFdPrivate;
+   friend class ZstdFileFdPrivate;
+   friend class DirectFileFdPrivate;
+   friend class PipedFileFdPrivate;
+   protected:
+   int iFd;
+ 
+   enum LocalFlags {AutoClose = (1<<0),Fail = (1<<1),DelOnFail = (1<<2),
+                    HitEof = (1<<3), Replace = (1<<4), Compressed = (1<<5) };
+   unsigned long Flags;
+   std::string FileName;
+   std::string TemporaryFileName;
+
+   public:
+   enum OpenMode {
+	ReadOnly = (1 << 0),
+	WriteOnly = (1 << 1),
+	ReadWrite = ReadOnly | WriteOnly,
+
+	Create = (1 << 2),
+	Exclusive = (1 << 3),
+	Atomic = Exclusive | (1 << 4),
+	Empty = (1 << 5),
+	BufferedWrite = (1 << 6),
+
+	WriteEmpty = ReadWrite | Create | Empty,
+	WriteExists = ReadWrite,
+	WriteAny = ReadWrite | Create,
+	WriteTemp = ReadWrite | Create | Exclusive,
+	ReadOnlyGzip,
+	WriteAtomic = ReadWrite | Create | Atomic
+   };
+   enum CompressMode
+   {
+      Auto = 'A',
+      None = 'N',
+      Extension = 'E',
+      Gzip = 'G',
+      Bzip2 = 'B',
+      Lzma = 'L',
+      Xz = 'X',
+      Lz4 = '4',
+      Zstd = 'Z'
+   };
+
+   inline bool Read(void *To,unsigned long long Size,bool AllowEof)
+   {
+      unsigned long long Jnk;
+      if (AllowEof)
+	 return Read(To,Size,&Jnk);
+      return Read(To,Size);
+   }   
+   bool Read(void *To,unsigned long long Size,unsigned long long *Actual = 0);
+   bool static Read(int const Fd, void *To, unsigned long long Size, unsigned long long * const Actual = 0);
+   /** read a complete line or until buffer is full
+    *
+    * The buffer will always be \\0 terminated, so at most Size-1 characters are read.
+    * If the buffer holds a complete line the last character (before \\0) will be
+    * the newline character \\n otherwise the line was longer than the buffer.
+    *
+    * @param To buffer which will hold the line
+    * @param Size of the buffer to fill
+    * @param \b nullptr is returned in error cases, otherwise
+    * the parameter \b To now filled with the line.
+    */
+   char* ReadLine(char *To, unsigned long long const Size);
+   /** read a complete line from the file
+    *
+    *  Similar to std::getline() the string does \b not include
+    *  the newline, but just the content of the line as the newline
+    *  is not needed to distinguish cases as for the other #ReadLine method.
+    *
+    *  @param To string which will hold the line
+    *  @return \b true if successful, otherwise \b false
+    */
+   bool ReadLine(std::string &To);
+   bool Flush();
+   bool Write(const void *From,unsigned long long Size);
+   bool static Write(int Fd, const void *From, unsigned long long Size);
+   bool Seek(unsigned long long To);
+   bool Skip(unsigned long long To);
+   bool Truncate(unsigned long long To);
+   unsigned long long Tell();
+   // the size of the file content (compressed files will be uncompressed first)
+   unsigned long long Size();
+   // the size of the file itself
+   unsigned long long FileSize();
+   time_t ModificationTime();
+
+   bool Open(std::string FileName,unsigned int const Mode,CompressMode Compress,unsigned long const AccessMode = 0666);
+   bool Open(std::string FileName,unsigned int const Mode,APT::Configuration::Compressor const &compressor,unsigned long const AccessMode = 0666);
+   inline bool Open(std::string const &FileName,unsigned int const Mode, unsigned long const AccessMode = 0666) {
+      return Open(FileName, Mode, None, AccessMode);
+   };
+   bool OpenDescriptor(int Fd, unsigned int const Mode, CompressMode Compress, bool AutoClose=false);
+   bool OpenDescriptor(int Fd, unsigned int const Mode, APT::Configuration::Compressor const &compressor, bool AutoClose=false);
+   inline bool OpenDescriptor(int Fd, unsigned int const Mode, bool AutoClose=false) {
+      return OpenDescriptor(Fd, Mode, None, AutoClose);
+   };
+   bool Close();
+   bool Sync();
+   
+   // Simple manipulators
+   inline int Fd() {return iFd;};
+   inline void Fd(int fd) { OpenDescriptor(fd, ReadWrite);};
+
+   inline bool IsOpen() {return iFd >= 0;};
+   inline bool Failed() {return (Flags & Fail) == Fail;};
+   inline void EraseOnFailure() {Flags |= DelOnFail;};
+   inline void OpFail() {Flags |= Fail;};
+   inline bool Eof() {return (Flags & HitEof) == HitEof;};
+   inline bool IsCompressed() {return (Flags & Compressed) == Compressed;};
+   inline std::string &Name() {return FileName;};
+   inline void SetFileName(std::string const &name) { FileName = name; };
+
+   FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode = 0666);
+   FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode = 0666);
+   FileFd();
+   FileFd(int const Fd, unsigned int const Mode = ReadWrite, CompressMode Compress = None);
+   FileFd(int const Fd, bool const AutoClose);
+   virtual ~FileFd();
+
+   private:
+   FileFdPrivate * d;
+   APT_HIDDEN FileFd(const FileFd &);
+   APT_HIDDEN FileFd & operator=(const FileFd &);
+   APT_HIDDEN bool OpenInternDescriptor(unsigned int const Mode, APT::Configuration::Compressor const &compressor);
+
+   // private helpers to set Fail flag and call _error->Error
+   APT_HIDDEN bool FileFdErrno(const char* Function, const char* Description,...) APT_PRINTF(3) APT_COLD;
+   APT_HIDDEN bool FileFdError(const char* Description,...) APT_PRINTF(2) APT_COLD;
+};
+
+APT_PUBLIC bool RunScripts(const char *Cnf);
+APT_PUBLIC bool CopyFile(FileFd &From,FileFd &To);
+APT_PUBLIC bool RemoveFile(char const * const Function, std::string const &FileName);
+APT_PUBLIC bool RemoveFileAt(char const * const Function, int const dirfd, std::string const &FileName);
+APT_PUBLIC int GetLock(std::string File,bool Errors = true);
+APT_PUBLIC bool FileExists(std::string File);
+APT_PUBLIC bool RealFileExists(std::string File);
+APT_PUBLIC bool DirectoryExists(std::string const &Path);
+APT_PUBLIC bool CreateDirectory(std::string const &Parent, std::string const &Path);
+APT_PUBLIC time_t GetModificationTime(std::string const &Path);
+APT_PUBLIC bool Rename(std::string From, std::string To);
+
+APT_PUBLIC std::string GetTempDir();
+APT_PUBLIC std::string GetTempDir(std::string const &User);
+APT_PUBLIC FileFd* GetTempFile(std::string const &Prefix = "",
+                    bool ImmediateUnlink = true,
+		    FileFd * const TmpFd = NULL);
+
+// FIXME: GetTempFile should always return a buffered file
+APT_HIDDEN FileFd* GetTempFile(std::string const &Prefix,
+                    bool ImmediateUnlink ,
+		    FileFd * const TmpFd,
+          bool Buffered);
+
+/** \brief Ensure the existence of the given Path
+ *
+ *  \param Parent directory of the Path directory - a trailing
+ *  /apt/ will be removed before CreateDirectory call.
+ *  \param Path which should exist after (successful) call
+ */
+APT_PUBLIC bool CreateAPTDirectoryIfNeeded(std::string const &Parent, std::string const &Path);
+
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, std::string const &Ext,
+					bool const &SortList, bool const &AllowNoExt=false);
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, std::vector<std::string> const &Ext,
+					bool const &SortList);
+APT_PUBLIC std::vector<std::string> GetListOfFilesInDir(std::string const &Dir, bool SortList);
+APT_PUBLIC std::string SafeGetCWD();
+APT_PUBLIC void SetCloseExec(int Fd,bool Close);
+APT_PUBLIC void SetNonBlock(int Fd,bool Block);
+APT_PUBLIC bool WaitFd(int Fd,bool write = false,unsigned long timeout = 0);
+APT_PUBLIC pid_t ExecFork();
+APT_PUBLIC pid_t ExecFork(std::set<int> keep_fds);
+APT_PUBLIC void MergeKeepFdsFromConfiguration(std::set<int> &keep_fds);
+APT_PUBLIC bool ExecWait(pid_t Pid,const char *Name,bool Reap = false);
+
+// check if the given file starts with a PGP cleartext signature
+APT_PUBLIC bool StartsWithGPGClearTextSignature(std::string const &FileName);
+
+/** change file attributes to requested known good values
+ *
+ * The method skips the user:group setting if not root.
+ *
+ * @param requester is printed as functionname in error cases
+ * @param file is the file to be modified
+ * @param user is the (new) owner of the file, e.g. _apt
+ * @param group is the (new) group owning the file, e.g. root
+ * @param mode is the access mode of the file, e.g. 0644
+ */
+APT_PUBLIC bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode);
+
+/**
+ * \brief Drop privileges
+ *
+ * Drop the privileges to the user _apt (or the one specified in
+ * APT::Sandbox::User). This does not set the supplementary group
+ * ids up correctly, it only uses the default group. Also prevent
+ * the process from gaining any new privileges afterwards, at least
+ * on Linux.
+ *
+ * \return true on success, false on failure with _error set
+ */
+APT_PUBLIC bool DropPrivileges();
+
+// File string manipulators
+APT_PUBLIC std::string flNotDir(std::string File);
+APT_PUBLIC std::string flNotFile(std::string File);
+APT_PUBLIC std::string flNoLink(std::string File);
+APT_PUBLIC std::string flExtension(std::string File);
+APT_PUBLIC std::string flCombine(std::string Dir,std::string File);
+
+/** \brief Takes a file path and returns the absolute path
+ */
+APT_PUBLIC std::string flAbsPath(std::string File);
+/** \brief removes superfluous /./ and // from path */
+APT_HIDDEN std::string flNormalize(std::string file);
+
+// simple c++ glob
+APT_PUBLIC std::vector<std::string> Glob(std::string const &pattern, int flags=0);
+
+/** \brief Popen() implementation that execv() instead of using a shell
+ *
+ * \param Args the execv style command to run
+ * \param FileFd is a reference to the FileFd to use for input or output
+ * \param Child a reference to the integer that stores the child pid
+ *        Note that you must call ExecWait() or similar to cleanup
+ * \param Mode is either FileFd::ReadOnly or FileFd::WriteOnly
+ * \param CaptureStderr True if we should capture stderr in addition to stdout.
+ *                      (default: True).
+ * \param Sandbox True if this should run sandboxed
+ * \return true on success, false on failure with _error set
+ */
+APT_PUBLIC bool Popen(const char *Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode, bool CaptureStderr = true, bool Sandbox = false);
+
+APT_HIDDEN bool OpenConfigurationFileFd(std::string const &File, FileFd &Fd);
+
+APT_HIDDEN int Inhibit(const char *what, const char *who, const char *why, const char *mode);
+
+#endif
diff --git a/apt-pkg/contrib/gpgv.cc b/apt-pkg/contrib/gpgv.cc
new file mode 100644
index 0000000..3368ece
--- /dev/null
+++ b/apt-pkg/contrib/gpgv.cc
@@ -0,0 +1,568 @@
+// -*- mode: cpp; mode: fold -*-
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/strutl.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// syntactic sugar to wrap a raw pointer with a custom deleter in a std::unique_ptr
+static std::unique_ptr<char, decltype(&free)> make_unique_char(void *const str = nullptr)
+{
+   return {static_cast<char *>(str), &free};
+}
+static std::unique_ptr<FILE, decltype(&fclose)> make_unique_FILE(std::string const &filename, char const *const mode)
+{
+   return {fopen(filename.c_str(), mode), &fclose};
+}
+
+class LineBuffer							/*{{{*/
+{
+   char *buffer = nullptr;
+   size_t buffer_size = 0;
+   int line_length = 0;
+   // a "normal" find_last_not_of returns npos if not found
+   int find_last_not_of_length(APT::StringView const bad) const
+   {
+      for (int result = line_length - 1; result >= 0; --result)
+	 if (bad.find(buffer[result]) == APT::StringView::npos)
+	    return result + 1;
+      return 0;
+   }
+
+   public:
+   bool empty() const noexcept { return view().empty(); }
+   APT::StringView view() const noexcept { return {buffer, static_cast<size_t>(line_length)}; }
+   bool starts_with(APT::StringView const start) const { return view().substr(0, start.size()) == start; }
+
+   bool writeTo(FileFd *const to, size_t offset = 0) const
+   {
+      if (to == nullptr)
+	 return true;
+      return to->Write(buffer + offset, line_length - offset);
+   }
+   bool writeLineTo(FileFd *const to) const
+    {
+       if (to == nullptr)
+         return true;
+       buffer[line_length] = '\n';
+       bool const result = to->Write(buffer, line_length + 1);
+       buffer[line_length] = '\0';
+       return result;
+    }
+   bool writeNewLineIf(FileFd *const to, bool const condition) const
+   {
+      if (not condition || to == nullptr)
+	 return true;
+      return to->Write("\n", 1);
+   }
+
+   bool readFrom(FILE *stream, std::string const &InFile, bool acceptEoF = false)
+   {
+      errno = 0;
+      line_length = getline(&buffer, &buffer_size, stream);
+      if (errno != 0)
+	 return _error->Errno("getline", "Could not read from %s", InFile.c_str());
+      if (line_length == -1)
+      {
+	 if (acceptEoF)
+	    return false;
+	 return _error->Error("Splitting of clearsigned file %s failed as it doesn't contain all expected parts", InFile.c_str());
+      }
+      // a) remove newline characters, so we can work consistently with lines
+      line_length = find_last_not_of_length("\n\r");
+      // b) remove trailing whitespaces as defined by rfc4880 §7.1
+      line_length = find_last_not_of_length(" \t");
+      buffer[line_length] = '\0';
+      return true;
+   }
+
+   ~LineBuffer() { free(buffer); }
+};
+static bool operator==(LineBuffer const &buf, APT::StringView const exp) noexcept
+{
+   return buf.view() == exp;
+}
+static bool operator!=(LineBuffer const &buf, APT::StringView const exp) noexcept
+{
+   return buf.view() != exp;
+}
+									/*}}}*/
+// ExecGPGV - returns the command needed for verify			/*{{{*/
+// ---------------------------------------------------------------------
+/* Generating the commandline for calling gpg is somehow complicated as
+   we need to add multiple keyrings and user supplied options.
+   Also, as gpg has no options to enforce a certain reduced style of
+   clear-signed files (=the complete content of the file is signed and
+   the content isn't encoded) we do a divide and conquer approach here
+   and split up the clear-signed file in message and signature for gpg.
+   And as a cherry on the cake, we use our apt-key wrapper to do part
+   of the lifting in regards to merging keyrings. Fun for the whole family.
+*/
+static void APT_PRINTF(4) apt_error(std::ostream &outterm, int const statusfd, int fd[2], const char *format, ...)
+{
+   std::ostringstream outstr;
+   std::ostream &out = (statusfd == -1) ? outterm : outstr;
+   va_list args;
+   ssize_t size = 400;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(out, format, args, size);
+      va_end(args);
+      if (ret)
+	 break;
+   }
+   if (statusfd != -1)
+   {
+      auto const errtag = "[APTKEY:] ERROR ";
+      outstr << '\n';
+      auto const errtext = outstr.str();
+      if (not FileFd::Write(fd[1], errtag, strlen(errtag)) ||
+	    not FileFd::Write(fd[1], errtext.data(), errtext.size()))
+	 outterm << errtext << std::flush;
+   }
+}
+void ExecGPGV(std::string const &File, std::string const &FileGPG,
+             int const &statusfd, int fd[2], std::string const &key)
+{
+   #define EINTERNAL 111
+   std::string const aptkey = _config->Find("Dir::Bin::apt-key", CMAKE_INSTALL_FULL_BINDIR "/apt-key");
+
+   bool const Debug = _config->FindB("Debug::Acquire::gpgv", false);
+   struct exiter {
+      std::vector<const char *> files;
+      void operator ()(int code) APT_NORETURN {
+	 std::for_each(files.begin(), files.end(), unlink);
+	 exit(code);
+      }
+   } local_exit;
+
+
+   std::vector<const char *> Args;
+   Args.reserve(10);
+
+   Args.push_back(aptkey.c_str());
+   Args.push_back("--quiet");
+   Args.push_back("--readonly");
+   auto const keysFileFpr = VectorizeString(key, ',');
+   for (auto const &k: keysFileFpr)
+   {
+      if (unlikely(k.empty()))
+	 continue;
+      if (k[0] == '/')
+      {
+	 Args.push_back("--keyring");
+	 Args.push_back(k.c_str());
+      }
+      else
+      {
+	 Args.push_back("--keyid");
+	 Args.push_back(k.c_str());
+      }
+   }
+   Args.push_back("verify");
+
+   char statusfdstr[10];
+   if (statusfd != -1)
+   {
+      Args.push_back("--status-fd");
+      snprintf(statusfdstr, sizeof(statusfdstr), "%i", statusfd);
+      Args.push_back(statusfdstr);
+   }
+
+   Configuration::Item const *Opts;
+   Opts = _config->Tree("Acquire::gpgv::Options");
+   if (Opts != 0)
+   {
+      Opts = Opts->Child;
+      for (; Opts != 0; Opts = Opts->Next)
+      {
+	 if (Opts->Value.empty())
+	    continue;
+	 Args.push_back(Opts->Value.c_str());
+      }
+   }
+
+   enum  { DETACHED, CLEARSIGNED } releaseSignature = (FileGPG != File) ? DETACHED : CLEARSIGNED;
+   auto sig = make_unique_char();
+   auto data = make_unique_char();
+   auto conf = make_unique_char();
+
+   // Dump the configuration so apt-key picks up the correct Dir values
+   {
+      {
+	 std::string tmpfile;
+	 strprintf(tmpfile, "%s/apt.conf.XXXXXX", GetTempDir().c_str());
+	 conf.reset(strdup(tmpfile.c_str()));
+      }
+      if (conf == nullptr) {
+	 apt_error(std::cerr, statusfd, fd, "Couldn't create tempfile names for passing config to apt-key");
+	 local_exit(EINTERNAL);
+      }
+      int confFd = mkstemp(conf.get());
+      if (confFd == -1) {
+	 apt_error(std::cerr, statusfd, fd, "Couldn't create temporary file %s for passing config to apt-key", conf.get());
+	 local_exit(EINTERNAL);
+      }
+      local_exit.files.push_back(conf.get());
+
+      std::ofstream confStream(conf.get());
+      close(confFd);
+      _config->Dump(confStream);
+      confStream.close();
+      setenv("APT_CONFIG", conf.get(), 1);
+   }
+
+   // Tell apt-key not to emit warnings
+   setenv("APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE", "1", 1);
+
+   if (releaseSignature == DETACHED)
+   {
+      auto detached = make_unique_FILE(FileGPG, "r");
+      if (detached.get() == nullptr)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' could not be opened", FileGPG.c_str());
+	 local_exit(EINTERNAL);
+      }
+      LineBuffer buf;
+      bool open_signature = false;
+      bool found_badcontent = false;
+      size_t found_signatures = 0;
+      while (buf.readFrom(detached.get(), FileGPG, true))
+      {
+	 if (open_signature)
+	 {
+	    if (buf == "-----END PGP SIGNATURE-----")
+	       open_signature = false;
+	    else if (buf.starts_with("-"))
+	    {
+	       // the used Radix-64 is not using dash for any value, so a valid line can't
+	       // start with one. Header keys could, but no existent one does and seems unlikely.
+	       // Instead it smells a lot like a header the parser didn't recognize.
+	       apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains unexpected line starting with a dash", FileGPG.c_str());
+	       local_exit(112);
+	    }
+	 }
+	 else //if (not open_signature)
+	 {
+	    if (buf == "-----BEGIN PGP SIGNATURE-----")
+	    {
+	       open_signature = true;
+	       ++found_signatures;
+	       if (found_badcontent)
+		  break;
+	    }
+	    else
+	    {
+	       found_badcontent = true;
+	       if (found_signatures != 0)
+		  break;
+	    }
+	 }
+      }
+      if (found_signatures == 0 && statusfd != -1)
+      {
+	 auto const errtag = "[GNUPG:] NODATA\n";
+	 FileFd::Write(fd[1], errtag, strlen(errtag));
+	 // guess if this is a binary signature, we never officially supported them,
+	 // but silently accepted them via passing them unchecked to gpgv
+	 if (found_badcontent)
+	 {
+	    rewind(detached.get());
+	    auto ptag = fgetc(detached.get());
+	    // §4.2 says that the first bit is always set and gpg seems to generate
+	    // only old format which is indicated by the second bit not set
+	    if (ptag != EOF && (ptag & 0x80) != 0 && (ptag & 0x40) == 0)
+	    {
+	       apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' is in unsupported binary format", FileGPG.c_str());
+	       local_exit(112);
+	    }
+	 }
+	 // This is not an attack attempt but a file even gpgv would complain about
+	 // likely the result of a paywall which is covered by the gpgv method
+	 local_exit(113);
+      }
+      else if (found_badcontent)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains lines not belonging to a signature", FileGPG.c_str());
+	 local_exit(112);
+      }
+      if (open_signature)
+      {
+	 apt_error(std::cerr, statusfd, fd, "Detached signature file '%s' contains unclosed signatures", FileGPG.c_str());
+	 local_exit(112);
+      }
+
+      Args.push_back(FileGPG.c_str());
+      Args.push_back(File.c_str());
+   }
+   else // clear-signed file
+   {
+      FileFd signature;
+      if (GetTempFile("apt.sig", false, &signature) == nullptr)
+	 local_exit(EINTERNAL);
+      sig.reset(strdup(signature.Name().c_str()));
+      local_exit.files.push_back(sig.get());
+      FileFd message;
+      if (GetTempFile("apt.data", false, &message) == nullptr)
+	 local_exit(EINTERNAL);
+      data.reset(strdup(message.Name().c_str()));
+      local_exit.files.push_back(data.get());
+
+      if (signature.Failed() || message.Failed() ||
+	  not SplitClearSignedFile(File, &message, nullptr, &signature))
+      {
+	 apt_error(std::cerr, statusfd, fd, "Splitting up %s into data and signature failed", File.c_str());
+	 local_exit(112);
+      }
+      Args.push_back(sig.get());
+      Args.push_back(data.get());
+   }
+
+   Args.push_back(NULL);
+
+   if (Debug)
+   {
+      std::clog << "Preparing to exec: ";
+      for (std::vector<const char *>::const_iterator a = Args.begin(); *a != NULL; ++a)
+	 std::clog << " " << *a;
+      std::clog << std::endl;
+   }
+
+   if (statusfd != -1)
+   {
+      int const nullfd = open("/dev/null", O_WRONLY);
+      close(fd[0]);
+      // Redirect output to /dev/null; we read from the status fd
+      if (statusfd != STDOUT_FILENO)
+	 dup2(nullfd, STDOUT_FILENO);
+      if (statusfd != STDERR_FILENO)
+	 dup2(nullfd, STDERR_FILENO);
+      // Redirect the pipe to the status fd (3)
+      dup2(fd[1], statusfd);
+
+      putenv((char *)"LANG=");
+      putenv((char *)"LC_ALL=");
+      putenv((char *)"LC_MESSAGES=");
+   }
+
+
+   // We have created tempfiles we have to clean up
+   // and we do an additional check, so fork yet another time …
+   pid_t pid = ExecFork();
+   if(pid < 0) {
+      apt_error(std::cerr, statusfd, fd, "Fork failed for %s to check %s", Args[0], File.c_str());
+      local_exit(EINTERNAL);
+   }
+   if(pid == 0)
+   {
+      if (statusfd != -1)
+	 dup2(fd[1], statusfd);
+      execvp(Args[0], (char **) &Args[0]);
+      apt_error(std::cerr, statusfd, fd, "Couldn't execute %s to check %s", Args[0], File.c_str());
+      local_exit(EINTERNAL);
+   }
+
+   // Wait and collect the error code - taken from WaitPid as we need the exact Status
+   int Status;
+   while (waitpid(pid,&Status,0) != pid)
+   {
+      if (errno == EINTR)
+	 continue;
+      apt_error(std::cerr, statusfd, fd, _("Waited for %s but it wasn't there"), "apt-key");
+      local_exit(EINTERNAL);
+   }
+
+   // check if it exit'ed normally …
+   if (not WIFEXITED(Status))
+   {
+      apt_error(std::cerr, statusfd, fd, _("Sub-process %s exited unexpectedly"), "apt-key");
+      local_exit(EINTERNAL);
+   }
+
+   // … and with a good exit code
+   if (WEXITSTATUS(Status) != 0)
+   {
+      // we forward the statuscode, so don't generate a message on the fd in this case
+      apt_error(std::cerr, -1, fd, _("Sub-process %s returned an error code (%u)"), "apt-key", WEXITSTATUS(Status));
+      local_exit(WEXITSTATUS(Status));
+   }
+
+   // everything fine
+   local_exit(0);
+}
+									/*}}}*/
+// SplitClearSignedFile - split message into data/signature		/*{{{*/
+bool SplitClearSignedFile(std::string const &InFile, FileFd * const ContentFile,
+      std::vector<std::string> * const ContentHeader, FileFd * const SignatureFile)
+{
+   auto in = make_unique_FILE(InFile, "r");
+   if (in.get() == nullptr)
+      return _error->Errno("fopen", "can not open %s", InFile.c_str());
+
+   struct ScopedErrors
+   {
+      ScopedErrors() { _error->PushToStack(); }
+      ~ScopedErrors() { _error->MergeWithStack(); }
+   } scoped;
+   LineBuffer buf;
+
+   // start of the message
+   if (not buf.readFrom(in.get(), InFile))
+      return false; // empty or read error
+   if (buf != "-----BEGIN PGP SIGNED MESSAGE-----")
+   {
+      // this might be an unsigned file we don't want to report errors for,
+      // but still finish unsuccessful none the less.
+      while (buf.readFrom(in.get(), InFile, true))
+	 if (buf == "-----BEGIN PGP SIGNED MESSAGE-----")
+	    return _error->Error("Clearsigned file '%s' does not start with a signed message block.", InFile.c_str());
+
+      return false;
+   }
+
+   // save "Hash" Armor Headers
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile))
+	 return false;
+      if (buf.empty())
+	 break; // empty line ends the Armor Headers
+      if (buf.starts_with("-"))
+	 // § 6.2 says unknown keys should be reported to the user. We don't go that far,
+	 // but we assume that there will never be a header key starting with a dash
+	 return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "armor");
+      if (ContentHeader != nullptr && buf.starts_with("Hash: "))
+	 ContentHeader->push_back(buf.view().to_string());
+   }
+
+   // the message itself
+   bool first_line = true;
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile))
+	 return false;
+
+      if (buf.starts_with("-"))
+      {
+	 if (buf == "-----BEGIN PGP SIGNATURE-----")
+	 {
+	    if (not buf.writeLineTo(SignatureFile))
+	       return false;
+	    break;
+	 }
+	 else if (buf.starts_with("- "))
+	 {
+	    // we don't have any fields which need to be dash-escaped,
+	    // but implementations are free to escape all lines …
+	    if (not buf.writeNewLineIf(ContentFile, not first_line) || not buf.writeTo(ContentFile, 2))
+	       return false;
+	 }
+	 else
+	    // § 7.1 says a client should warn, but we don't really work with files which
+	    // should contain lines starting with a dash, so it is a lot more likely that
+	    // this is an attempt to trick our parser vs. gpgv parser into ignoring a header
+	    return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "msg");
+      }
+      else if (not buf.writeNewLineIf(ContentFile, not first_line) || not buf.writeTo(ContentFile))
+	 return false;
+      first_line = false;
+   }
+
+   // collect all signatures
+   bool open_signature = true;
+   while (true)
+   {
+      if (not buf.readFrom(in.get(), InFile, true))
+	 break;
+
+      if (open_signature)
+      {
+	 if (buf == "-----END PGP SIGNATURE-----")
+	    open_signature = false;
+	 else if (buf.starts_with("-"))
+	    // the used Radix-64 is not using dash for any value, so a valid line can't
+	    // start with one. Header keys could, but no existent one does and seems unlikely.
+	    // Instead it smells a lot like a header the parser didn't recognize.
+	    return _error->Error("Clearsigned file '%s' contains unexpected line starting with a dash (%s)", InFile.c_str(), "sig");
+      }
+      else //if (not open_signature)
+      {
+	 if (buf == "-----BEGIN PGP SIGNATURE-----")
+	    open_signature = true;
+	 else
+	    return _error->Error("Clearsigned file '%s' contains unsigned lines.", InFile.c_str());
+      }
+
+      if (not buf.writeLineTo(SignatureFile))
+	 return false;
+   }
+   if (open_signature)
+      return _error->Error("Signature in file %s wasn't closed", InFile.c_str());
+
+   // Flush the files
+   if (SignatureFile != nullptr)
+      SignatureFile->Flush();
+   if (ContentFile != nullptr)
+      ContentFile->Flush();
+
+   // Catch-all for "unhandled" read/sync errors
+   if (_error->PendingError())
+      return false;
+   return true;
+}
+									/*}}}*/
+bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile) /*{{{*/
+{
+   // Buffered file
+   if (GetTempFile("clearsigned.message", true, &MessageFile, true) == nullptr)
+      return false;
+   if (MessageFile.Failed())
+      return _error->Error("Couldn't open temporary file to work with %s", ClearSignedFileName.c_str());
+
+   _error->PushToStack();
+   bool const splitDone = SplitClearSignedFile(ClearSignedFileName, &MessageFile, NULL, NULL);
+   bool const errorDone = _error->PendingError();
+   _error->MergeWithStack();
+   if (not splitDone)
+   {
+      MessageFile.Close();
+
+      if (errorDone)
+	 return false;
+
+      // we deal with an unsigned file
+      MessageFile.Open(ClearSignedFileName, FileFd::ReadOnly);
+   }
+   else // clear-signed
+   {
+      if (not MessageFile.Seek(0))
+	 return _error->Errno("lseek", "Unable to seek back in message for file %s", ClearSignedFileName.c_str());
+   }
+
+   return not MessageFile.Failed();
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/gpgv.h b/apt-pkg/contrib/gpgv.h
new file mode 100644
index 0000000..1cabed4
--- /dev/null
+++ b/apt-pkg/contrib/gpgv.h
@@ -0,0 +1,89 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Helpers to deal with gpgv better and more easily
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef CONTRIB_GPGV_H
+#define CONTRIB_GPGV_H
+
+#include <apt-pkg/macros.h>
+
+#include <string>
+#include <vector>
+
+
+class FileFd;
+
+/** \brief generates and run the command to verify a file with gpgv
+ *
+ * If File and FileSig specify the same file it is assumed that we
+ * deal with a clear-signed message. Note that the method will accept
+ * and validate files which include additional (unsigned) messages
+ * without complaining. Do NOT open files accepted by this method
+ * for reading. Use #OpenMaybeClearSignedFile to access the message
+ * instead to ensure you are only reading signed data.
+ *
+ * The method does not return, but has some notable exit-codes:
+ * 111 signals an internal error like the inability to execute gpgv,
+ * 112 indicates a clear-signed file which doesn't include a message,
+ *  which can happen if APT is run while on a network requiring
+ *  authentication before usage (e.g. in hotels)
+ * All other exit-codes are passed-through from gpgv.
+ *
+ * @param File is the message (unsigned or clear-signed)
+ * @param FileSig is the signature (detached or clear-signed)
+ * @param statusfd is the fd given to gpgv as --status-fd
+ * @param fd is used as a pipe for the standard output of gpgv
+ * @param key is the specific one to be used instead of using all
+ */
+APT_PUBLIC void ExecGPGV(std::string const &File, std::string const &FileSig,
+      int const &statusfd, int fd[2], std::string const &Key = "") APT_NORETURN;
+inline APT_NORETURN void ExecGPGV(std::string const &File, std::string const &FileSig,
+      int const &statusfd = -1) {
+   int fd[2];
+   ExecGPGV(File, FileSig, statusfd, fd);
+}
+
+/** \brief Split an inline signature into message and signature
+ *
+ *  Takes a clear-signed message and puts the first signed message
+ *  in the content file and all signatures following it into the
+ *  second. Unsigned messages, additional messages as well as
+ *  whitespaces are discarded. The resulting files are suitable to
+ *  be checked with gpgv.
+ *
+ *  If a FileFd pointers is NULL it will not be used and the content
+ *  which would have been written to it is silently discarded.
+ *
+ *  The content of the split files is undefined if the splitting was
+ *  unsuccessful.
+ *
+ *  Note that trying to split an unsigned file will fail, but
+ *  not generate an error message.
+ *
+ *  @param InFile is the clear-signed file
+ *  @param ContentFile is the FileFd the message will be written to
+ *  @param ContentHeader is a list of all required Amored Headers for the message
+ *  @param SignatureFile is the FileFd all signatures will be written to
+ *  @return true if the splitting was successful, false otherwise
+ */
+APT_PUBLIC bool SplitClearSignedFile(std::string const &InFile, FileFd * const ContentFile,
+      std::vector<std::string> * const ContentHeader, FileFd * const SignatureFile);
+
+/** \brief open a file which might be clear-signed
+ *
+ * This method tries to extract the (signed) message of a file.
+ * If the file isn't signed it will just open the given filename.
+ * Otherwise the message is extracted to a temporary file which
+ * will be opened instead.
+ *
+ * @param ClearSignedFileName is the name of the file to open
+ * @param[out] MessageFile is the FileFd in which the file will be opened
+ * @return true if opening was successful, otherwise false
+ */
+APT_PUBLIC bool OpenMaybeClearSignedFile(std::string const &ClearSignedFileName, FileFd &MessageFile);
+
+#endif
diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
new file mode 100644
index 0000000..313b1d3
--- /dev/null
+++ b/apt-pkg/contrib/hashes.cc
@@ -0,0 +1,464 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Hashes - Simple wrapper around the hash functions
+   
+   This is just used to make building the methods simpler, this is the
+   only interface required..
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <gcrypt.h>
+									/*}}}*/
+
+static const constexpr struct HashAlgo
+{
+   const char *name;
+   int gcryAlgo;
+   Hashes::SupportedHashes ourAlgo;
+} Algorithms[] = {
+   {"MD5Sum", GCRY_MD_MD5, Hashes::MD5SUM},
+   {"SHA1", GCRY_MD_SHA1, Hashes::SHA1SUM},
+   {"SHA256", GCRY_MD_SHA256, Hashes::SHA256SUM},
+   {"SHA512", GCRY_MD_SHA512, Hashes::SHA512SUM},
+};
+
+const char * HashString::_SupportedHashes[] =
+{
+   "SHA512", "SHA256", "SHA1", "MD5Sum", "Checksum-FileSize", NULL
+};
+std::vector<HashString::HashSupportInfo> HashString::SupportedHashesInfo()
+{
+   return {{
+      { "SHA512",  pkgTagSection::Key::SHA512,"Checksums-Sha512", pkgTagSection::Key::Checksums_Sha512},
+      { "SHA256", pkgTagSection::Key::SHA256, "Checksums-Sha256", pkgTagSection::Key::Checksums_Sha256},
+      { "SHA1", pkgTagSection::Key::SHA1, "Checksums-Sha1", pkgTagSection::Key::Checksums_Sha1 },
+      { "MD5Sum", pkgTagSection::Key::MD5sum, "Files", pkgTagSection::Key::Files },
+   }};
+}
+
+HashString::HashString()
+{
+}
+
+HashString::HashString(std::string Type, std::string Hash) : Type(Type), Hash(Hash)
+{
+}
+
+HashString::HashString(std::string StringedHash)			/*{{{*/
+{
+   if (StringedHash.find(":") == std::string::npos)
+   {
+      // legacy: md5sum without "MD5Sum:" prefix
+      if (StringedHash.size() == 32)
+      {
+	 Type = "MD5Sum";
+	 Hash = StringedHash;
+      }
+      if(_config->FindB("Debug::Hashes",false) == true)
+	 std::clog << "HashString(string): invalid StringedHash " << StringedHash << std::endl;
+      return;
+   }
+   std::string::size_type pos = StringedHash.find(":");
+   Type = StringedHash.substr(0,pos);
+   Hash = StringedHash.substr(pos+1, StringedHash.size() - pos);
+
+   if(_config->FindB("Debug::Hashes",false) == true)
+      std::clog << "HashString(string): " << Type << " : " << Hash << std::endl;
+}
+									/*}}}*/
+bool HashString::VerifyFile(std::string filename) const			/*{{{*/
+{
+   std::string fileHash = GetHashForFile(filename);
+
+   if(_config->FindB("Debug::Hashes",false) == true)
+      std::clog << "HashString::VerifyFile: got: " << fileHash << " expected: " << toStr() << std::endl;
+
+   return (fileHash == Hash);
+}
+									/*}}}*/
+bool HashString::FromFile(std::string filename)          		/*{{{*/
+{
+   // pick the strongest hash
+   if (Type == "")
+      Type = _SupportedHashes[0];
+
+   Hash = GetHashForFile(filename);
+   return true;
+}
+									/*}}}*/
+std::string HashString::GetHashForFile(std::string filename) const      /*{{{*/
+{
+   std::string fileHash;
+
+   FileFd Fd(filename, FileFd::ReadOnly);
+   if(strcasecmp(Type.c_str(), "MD5Sum") == 0)
+   {
+      Hashes MD5(Hashes::MD5SUM);
+      MD5.AddFD(Fd);
+      fileHash = MD5.GetHashString(Hashes::MD5SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA1") == 0)
+   {
+      Hashes SHA1(Hashes::SHA1SUM);
+      SHA1.AddFD(Fd);
+      fileHash = SHA1.GetHashString(Hashes::SHA1SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA256") == 0)
+   {
+      Hashes SHA256(Hashes::SHA256SUM);
+      SHA256.AddFD(Fd);
+      fileHash = SHA256.GetHashString(Hashes::SHA256SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "SHA512") == 0)
+   {
+      Hashes SHA512(Hashes::SHA512SUM);
+      SHA512.AddFD(Fd);
+      fileHash = SHA512.GetHashString(Hashes::SHA512SUM).Hash;
+   }
+   else if (strcasecmp(Type.c_str(), "Checksum-FileSize") == 0)
+      strprintf(fileHash, "%llu", Fd.FileSize());
+   Fd.Close();
+
+   return fileHash;
+}
+									/*}}}*/
+const char** HashString::SupportedHashes()				/*{{{*/
+{
+   return _SupportedHashes;
+}
+									/*}}}*/
+APT_PURE bool HashString::empty() const					/*{{{*/
+{
+   return (Type.empty() || Hash.empty());
+}
+									/*}}}*/
+
+APT_PURE static bool IsConfigured(const char *name, const char *what)
+{
+   std::string option;
+   strprintf(option, "APT::Hashes::%s::%s", name, what);
+   return _config->FindB(option, false);
+}
+
+APT_PURE bool HashString::usable() const				/*{{{*/
+{
+   return (
+      (Type != "Checksum-FileSize") &&
+      (Type != "MD5Sum") &&
+      (Type != "SHA1") &&
+      !IsConfigured(Type.c_str(), "Untrusted")
+   );
+}
+									/*}}}*/
+std::string HashString::toStr() const					/*{{{*/
+{
+   return Type + ":" + Hash;
+}
+									/*}}}*/
+APT_PURE bool HashString::operator==(HashString const &other) const	/*{{{*/
+{
+   return (strcasecmp(Type.c_str(), other.Type.c_str()) == 0 && Hash == other.Hash);
+}
+APT_PURE bool HashString::operator!=(HashString const &other) const
+{
+   return !(*this == other);
+}
+									/*}}}*/
+
+bool HashStringList::usable() const					/*{{{*/
+{
+   if (empty() == true)
+      return false;
+   std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+   if (forcedType.empty() == true)
+   {
+      // See if there is at least one usable hash
+      return std::any_of(list.begin(), list.end(), [](auto const &hs) { return hs.usable(); });
+   }
+   return find(forcedType) != NULL;
+}
+									/*}}}*/
+HashString const * HashStringList::find(char const * const type) const /*{{{*/
+{
+   if (type == NULL || type[0] == '\0')
+   {
+      std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+      if (forcedType.empty() == false)
+	 return find(forcedType.c_str());
+      for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t)
+	 for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs)
+	    if (strcasecmp(hs->HashType().c_str(), *t) == 0)
+	       return &*hs;
+      return NULL;
+   }
+   for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs)
+      if (strcasecmp(hs->HashType().c_str(), type) == 0)
+	 return &*hs;
+   return NULL;
+}
+									/*}}}*/
+unsigned long long HashStringList::FileSize() const			/*{{{*/
+{
+   HashString const * const hsf = find("Checksum-FileSize");
+   if (hsf == NULL)
+      return 0;
+   std::string const hv = hsf->HashValue();
+   return strtoull(hv.c_str(), NULL, 10);
+}
+									/*}}}*/
+bool HashStringList::FileSize(unsigned long long const Size)		/*{{{*/
+{
+   return push_back(HashString("Checksum-FileSize", std::to_string(Size)));
+}
+									/*}}}*/
+bool HashStringList::supported(char const * const type)			/*{{{*/
+{
+   for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t)
+      if (strcasecmp(*t, type) == 0)
+	 return true;
+   return false;
+}
+									/*}}}*/
+bool HashStringList::push_back(const HashString &hashString)		/*{{{*/
+{
+   if (hashString.HashType().empty() == true ||
+	 hashString.HashValue().empty() == true ||
+	 supported(hashString.HashType().c_str()) == false)
+      return false;
+
+   // ensure that each type is added only once
+   HashString const * const hs = find(hashString.HashType().c_str());
+   if (hs != NULL)
+      return *hs == hashString;
+
+   list.push_back(hashString);
+   return true;
+}
+									/*}}}*/
+bool HashStringList::VerifyFile(std::string filename) const		/*{{{*/
+{
+   if (usable() == false)
+      return false;
+
+   Hashes hashes(*this);
+   FileFd file(filename, FileFd::ReadOnly);
+   HashString const * const hsf = find("Checksum-FileSize");
+   if (hsf != NULL)
+   {
+      std::string fileSize;
+      strprintf(fileSize, "%llu", file.FileSize());
+      if (hsf->HashValue() != fileSize)
+	 return false;
+   }
+   hashes.AddFD(file);
+   HashStringList const hsl = hashes.GetHashStringList();
+   return hsl == *this;
+}
+									/*}}}*/
+bool HashStringList::operator==(HashStringList const &other) const	/*{{{*/
+{
+   std::string const forcedType = _config->Find("Acquire::ForceHash", "");
+   if (forcedType.empty() == false)
+   {
+      HashString const * const hs = find(forcedType);
+      HashString const * const ohs = other.find(forcedType);
+      if (hs == NULL || ohs == NULL)
+	 return false;
+      return *hs == *ohs;
+   }
+   short matches = 0;
+   for (const_iterator hs = begin(); hs != end(); ++hs)
+   {
+      HashString const * const ohs = other.find(hs->HashType());
+      if (ohs == NULL)
+	 continue;
+      if (*hs != *ohs)
+	 return false;
+      ++matches;
+   }
+   if (matches == 0)
+      return false;
+   return true;
+}
+bool HashStringList::operator!=(HashStringList const &other) const
+{
+   return !(*this == other);
+}
+									/*}}}*/
+
+// PrivateHashes							/*{{{*/
+class PrivateHashes {
+public:
+   unsigned long long FileSize;
+   gcry_md_hd_t hd;
+
+   void maybeInit()
+   {
+
+      // Yikes, we got to initialize libgcrypt, or we get warnings. But we
+      // abstract away libgcrypt in Hashes from our users - they are not
+      // supposed to know what the hashing backend is, so we can't force
+      // them to init themselves as libgcrypt folks want us to. So this
+      // only leaves us with this option...
+      if (!gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
+      {
+	 if (!gcry_check_version(nullptr))
+	 {
+	    fprintf(stderr, "libgcrypt is too old (need %s, have %s)\n",
+		    "nullptr", gcry_check_version(NULL));
+	    exit(2);
+	 }
+
+	 gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+      }
+   }
+
+   explicit PrivateHashes(unsigned int const CalcHashes) : FileSize(0)
+   {
+      maybeInit();
+      gcry_md_open(&hd, 0, 0);
+      for (auto & Algo : Algorithms)
+      {
+	 if ((CalcHashes & Algo.ourAlgo) == Algo.ourAlgo)
+	    gcry_md_enable(hd, Algo.gcryAlgo);
+      }
+   }
+
+   explicit PrivateHashes(HashStringList const &Hashes) : FileSize(0) {
+      maybeInit();
+      gcry_md_open(&hd, 0, 0);
+      for (auto & Algo : Algorithms)
+      {
+	 if (not Hashes.usable() || Hashes.find(Algo.name) != NULL)
+	    gcry_md_enable(hd, Algo.gcryAlgo);
+      }
+   }
+   ~PrivateHashes()
+   {
+      gcry_md_close(hd);
+   }
+};
+									/*}}}*/
+// Hashes::Add* - Add the contents of data or FD			/*{{{*/
+bool Hashes::Add(const unsigned char * const Data, unsigned long long const Size)
+{
+   if (Size != 0)
+   {
+      gcry_md_write(d->hd, Data, Size);
+      d->FileSize += Size;
+   }
+   return true;
+}
+bool Hashes::AddFD(int const Fd,unsigned long long Size)
+{
+   unsigned char Buf[APT_BUFFER_SIZE];
+   bool const ToEOF = (Size == UntilEOF);
+   while (Size != 0 || ToEOF)
+   {
+      decltype(Size) n = sizeof(Buf);
+      if (!ToEOF) n = std::min(Size, n);
+      ssize_t const Res = read(Fd,Buf,n);
+      if (Res < 0 || (!ToEOF && Res != (ssize_t) n)) // error, or short read
+	 return false;
+      if (ToEOF && Res == 0) // EOF
+	 break;
+      Size -= Res;
+      if (Add(Buf, Res) == false)
+	 return false;
+   }
+   return true;
+}
+bool Hashes::AddFD(FileFd &Fd,unsigned long long Size)
+{
+   unsigned char Buf[APT_BUFFER_SIZE];
+   bool const ToEOF = (Size == 0);
+   while (Size != 0 || ToEOF)
+   {
+      decltype(Size) n = sizeof(Buf);
+      if (!ToEOF) n = std::min(Size, n);
+      decltype(Size) a = 0;
+      if (Fd.Read(Buf, n, &a) == false) // error
+	 return false;
+      if (ToEOF == false)
+      {
+	 if (a != n) // short read
+	    return false;
+      }
+      else if (a == 0) // EOF
+	 break;
+      Size -= a;
+      if (Add(Buf, a) == false)
+	 return false;
+   }
+   return true;
+}
+									/*}}}*/
+
+static APT_PURE std::string HexDigest(gcry_md_hd_t hd, int algo)
+{
+   char Conv[16] =
+      {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b',
+       'c', 'd', 'e', 'f'};
+
+   auto Size = gcry_md_get_algo_dlen(algo);
+   assert(Size <= 512/8);
+   char Result[((Size)*2) + 1];
+   Result[(Size)*2] = 0;
+
+   auto Sum = gcry_md_read(hd, algo);
+
+   // Convert each char into two letters
+   size_t J = 0;
+   size_t I = 0;
+   for (; I != (Size)*2; J++, I += 2)
+   {
+      Result[I] = Conv[Sum[J] >> 4];
+      Result[I + 1] = Conv[Sum[J] & 0xF];
+   }
+   return std::string(Result);
+};
+
+HashStringList Hashes::GetHashStringList()
+{
+   HashStringList hashes;
+   for (auto & Algo : Algorithms)
+      if (gcry_md_is_enabled(d->hd, Algo.gcryAlgo))
+	 hashes.push_back(HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo)));
+   hashes.FileSize(d->FileSize);
+
+   return hashes;
+}
+
+HashString Hashes::GetHashString(SupportedHashes hash)
+{
+   for (auto & Algo : Algorithms)
+      if (hash == Algo.ourAlgo)
+	 return HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo));
+
+   abort();
+}
+Hashes::Hashes() : d(new PrivateHashes(~0)) { }
+Hashes::Hashes(unsigned int const Hashes) : d(new PrivateHashes(Hashes)) {}
+Hashes::Hashes(HashStringList const &Hashes) : d(new PrivateHashes(Hashes)) {}
+Hashes::~Hashes() { delete d; }
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
new file mode 100644
index 0000000..e259b4e
--- /dev/null
+++ b/apt-pkg/contrib/hashes.h
@@ -0,0 +1,222 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Hashes - Simple wrapper around the hash functions
+   
+   This is just used to make building the methods simpler, this is the
+   only interface required..
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef APTPKG_HASHES_H
+#define APTPKG_HASHES_H
+
+#include <apt-pkg/macros.h>
+
+#ifdef APT_COMPILING_APT
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/tagfile-keys.h>
+#endif
+
+#include <cstring>
+#include <string>
+#include <vector>
+
+
+
+class FileFd;
+
+// helper class that contains hash function name
+// and hash
+class APT_PUBLIC HashString
+{
+ protected:
+   std::string Type;
+   std::string Hash;
+   static const char * _SupportedHashes[10];
+
+   // internal helper
+   std::string GetHashForFile(std::string filename) const;
+
+ public:
+   HashString(std::string Type, std::string Hash);
+   explicit HashString(std::string StringedHashString);  // init from str as "type:hash"
+   HashString();
+
+   // get hash type used
+   std::string HashType() const { return Type; };
+   std::string HashValue() const { return Hash; };
+
+   // verify the given filename against the currently loaded hash
+   bool VerifyFile(std::string filename) const;
+
+   // generate a hash string from the given filename
+   bool FromFile(std::string filename);
+
+
+   // helper
+   std::string toStr() const;                    // convert to str as "type:hash"
+   bool empty() const;
+   bool usable() const;
+   bool operator==(HashString const &other) const;
+   bool operator!=(HashString const &other) const;
+
+   // return the list of hashes we support
+   static APT_PURE const char** SupportedHashes();
+#ifdef APT_COMPILING_APT
+   struct APT_HIDDEN HashSupportInfo {
+      APT::StringView name;
+      pkgTagSection::Key namekey;
+      APT::StringView chksumsname;
+      pkgTagSection::Key chksumskey;
+   };
+   APT_HIDDEN static std::vector<HashSupportInfo> SupportedHashesInfo();
+#endif
+};
+
+class APT_PUBLIC HashStringList
+{
+   public:
+   /** find best hash if no specific one is requested
+    *
+    * @param type of the checksum to return, can be \b NULL
+    * @return If type is \b NULL (or the empty string) it will
+    *  return the 'best' hash; otherwise the hash which was
+    *  specifically requested. If no hash is found \b NULL will be returned.
+    */
+   HashString const * find(char const * const type) const;
+   HashString const * find(std::string const &type) const { return find(type.c_str()); }
+
+   /** finds the filesize hash and returns it as number
+    *
+    * @return beware: if the size isn't known we return \b 0 here,
+    * just like we would do for an empty file. If that is a problem
+    * for you have to get the size manually out of the list.
+    */
+   unsigned long long FileSize() const;
+
+   /** sets the filesize hash
+    *
+    * @param Size of the file
+    * @return @see #push_back
+    */
+   bool FileSize(unsigned long long const Size);
+
+   /** check if the given hash type is supported
+    *
+    * @param type to check
+    * @return true if supported, otherwise false
+    */
+   static APT_PURE bool supported(char const * const type);
+   /** add the given #HashString to the list
+    *
+    * @param hashString to add
+    * @return true if the hash is added because it is supported and
+    *  not already a different hash of the same type included, otherwise false
+    */
+   bool push_back(const HashString &hashString);
+   /** @return size of the list of HashStrings */
+   size_t size() const { return list.size(); }
+
+   /** verify file against all hashes in the list
+    *
+    * @param filename to verify
+    * @return true if the file matches the hashsum, otherwise false
+    */
+   bool VerifyFile(std::string filename) const;
+
+   /** is the list empty ?
+    *
+    * @return \b true if the list is empty, otherwise \b false
+    */
+   bool empty() const { return list.empty(); }
+
+   /** has the list at least one good entry
+    *
+    * similar to #empty, but handles forced hashes.
+    *
+    * @return if no hash is forced, same result as #empty,
+    * if one is forced \b true if this has is available, \b false otherwise
+    */
+   bool usable() const;
+
+   typedef std::vector<HashString>::const_iterator const_iterator;
+
+   /** iterator to the first element */
+   const_iterator begin() const { return list.begin(); }
+
+   /** iterator to the end element */
+   const_iterator end() const { return list.end(); }
+
+   /** start fresh with a clear list */
+   void clear() { list.clear(); }
+
+   /** compare two HashStringList for similarity.
+    *
+    * Two lists are similar if at least one hashtype is in both lists
+    * and the hashsum matches. All hashes are checked by default,
+    * if one doesn't match false is returned regardless of how many
+    * matched before. If a hash is forced, only this hash is compared,
+    * all others are ignored.
+    */
+   bool operator==(HashStringList const &other) const;
+   bool operator!=(HashStringList const &other) const;
+
+   HashStringList() {}
+
+   // simplifying API-compatibility constructors
+   explicit HashStringList(std::string const &hash) {
+      if (hash.empty() == false)
+	 list.push_back(HashString(hash));
+   }
+   explicit HashStringList(char const * const hash) {
+      if (hash != NULL && hash[0] != '\0')
+	 list.push_back(HashString(hash));
+   }
+
+   private:
+   std::vector<HashString> list;
+};
+
+class PrivateHashes;
+class APT_PUBLIC Hashes
+{
+   PrivateHashes * const d;
+   public:
+   static const int UntilEOF = 0;
+
+   bool Add(const unsigned char * const Data, unsigned long long const Size) APT_NONNULL(2);
+   inline bool Add(const char * const Data) APT_NONNULL(2)
+   {return Add(reinterpret_cast<unsigned char const *>(Data),strlen(Data));};
+   inline bool Add(const char *const Data, unsigned long long const Size) APT_NONNULL(2)
+   {
+      return Add(reinterpret_cast<unsigned char const *>(Data), Size);
+   };
+   inline bool Add(const unsigned char * const Beg,const unsigned char * const End) APT_NONNULL(2,3)
+   {return Add(Beg,End-Beg);};
+
+   enum SupportedHashes { MD5SUM = (1 << 0), SHA1SUM = (1 << 1), SHA256SUM = (1 << 2),
+      SHA512SUM = (1 << 3) };
+   bool AddFD(int const Fd,unsigned long long Size = 0);
+   bool AddFD(FileFd &Fd,unsigned long long Size = 0);
+
+   HashStringList GetHashStringList();
+
+   /** Get a specific hash. It is an error to use a hash that was not hashes */
+   HashString GetHashString(SupportedHashes hash);
+
+   /** create a Hashes object to calculate all supported hashes
+    *
+    * If ALL is too much, you can limit which Hashes are calculated
+    * with the following other constructors which mention explicitly
+    * which hashes to generate. */
+   Hashes();
+   /** @param Hashes bitflag composed of #SupportedHashes */
+   explicit Hashes(unsigned int const Hashes);
+   /** @param Hashes is a list of hashes */
+   explicit Hashes(HashStringList const &Hashes);
+   virtual ~Hashes();
+};
+
+#endif
diff --git a/apt-pkg/contrib/header-is-private.h b/apt-pkg/contrib/header-is-private.h
new file mode 100644
index 0000000..201a40c
--- /dev/null
+++ b/apt-pkg/contrib/header-is-private.h
@@ -0,0 +1,3 @@
+#ifndef APT_COMPILING_APT
+#error Internal header without ABI stability. Should only be used by apt itself!
+#endif
diff --git a/apt-pkg/contrib/macros.h b/apt-pkg/contrib/macros.h
new file mode 100644
index 0000000..c08cd24
--- /dev/null
+++ b/apt-pkg/contrib/macros.h
@@ -0,0 +1,131 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Macros Header - Various useful macro definitions
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Brian C. White.
+   
+   ##################################################################### */
+									/*}}}*/
+// Private header
+#ifndef MACROS_H
+#define MACROS_H
+
+/* Useful count macro, use on an array of things and it will return the
+   number of items in the array */
+#define APT_ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+// Flag Macros
+#define	FLAG(f)			(1L << (f))
+#define	SETFLAG(v,f)	((v) |= FLAG(f))
+#define CLRFLAG(v,f)	((v) &=~FLAG(f))
+#define	CHKFLAG(v,f)	((v) &  FLAG(f) ? true : false)
+
+#ifdef __GNUC__
+#define APT_GCC_VERSION (__GNUC__ << 8 | __GNUC_MINOR__)
+#else
+#define APT_GCC_VERSION 0
+#endif
+
+#ifdef APT_COMPILING_APT
+/* likely() and unlikely() can be used to mark boolean expressions
+   as (not) likely true which will help the compiler to optimise */
+#if APT_GCC_VERSION >= 0x0300
+	#define likely(x)	__builtin_expect (!!(x), 1)
+	#define unlikely(x)	__builtin_expect (!!(x), 0)
+#else
+	#define likely(x)	(x)
+	#define unlikely(x)	(x)
+#endif
+#endif
+
+#if APT_GCC_VERSION >= 0x0300
+	#define APT_DEPRECATED	__attribute__ ((deprecated))
+	#define APT_DEPRECATED_MSG(X)	__attribute__ ((deprecated(X)))
+	// __attribute__((const)) is too dangerous for us, we end up using it wrongly
+	#define APT_PURE	__attribute__((pure))
+	#define APT_NORETURN	__attribute__((noreturn))
+	#define APT_PRINTF(n)	__attribute__((format(printf, n, n + 1)))
+	#define APT_WEAK        __attribute__((weak));
+	#define APT_UNUSED      __attribute__((unused))
+#else
+	#define APT_DEPRECATED
+	#define APT_DEPRECATED_MSG
+	#define APT_PURE
+	#define APT_NORETURN
+	#define APT_PRINTF(n)
+	#define APT_WEAK
+	#define APT_UNUSED
+#endif
+
+#if APT_GCC_VERSION > 0x0302
+	#define APT_NONNULL(...)	__attribute__((nonnull(__VA_ARGS__)))
+	#define APT_MUSTCHECK		__attribute__((warn_unused_result))
+#else
+	#define APT_NONNULL(...)
+	#define APT_MUSTCHECK
+#endif
+
+#if APT_GCC_VERSION >= 0x0400
+	#define APT_SENTINEL	__attribute__((sentinel))
+	#define APT_PUBLIC __attribute__ ((visibility ("default")))
+	#define APT_HIDDEN __attribute__ ((visibility ("hidden")))
+#else
+	#define APT_SENTINEL
+	#define APT_PUBLIC
+	#define APT_HIDDEN
+#endif
+
+// cold functions are unlikely() to be called
+#if APT_GCC_VERSION >= 0x0403
+	#define APT_COLD	__attribute__ ((__cold__))
+	#define APT_HOT		__attribute__ ((__hot__))
+#else
+	#define APT_COLD
+	#define APT_HOT
+#endif
+
+
+#if __GNUC__ >= 4
+	#define APT_IGNORE_DEPRECATED_PUSH \
+		_Pragma("GCC diagnostic push") \
+		_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+	#define APT_IGNORE_DEPRECATED_POP \
+		_Pragma("GCC diagnostic pop")
+	/* gcc has various problems with this shortcut, so prefer the long form */
+	#define APT_IGNORE_DEPRECATED(XXX) \
+		APT_IGNORE_DEPRECATED_PUSH \
+		XXX \
+		APT_IGNORE_DEPRECATED_POP
+#else
+	#define APT_IGNORE_DEPRECATED_PUSH
+	#define APT_IGNORE_DEPRECATED_POP
+	#define APT_IGNORE_DEPRECATED(XXX) XXX
+#endif
+
+#if __cplusplus >= 201103L
+	#define APT_OVERRIDE override
+#else
+	#define APT_OVERRIDE /* no c++11 standard */
+#endif
+
+// These lines are extracted by the makefiles and the buildsystem
+// Increasing MAJOR or MINOR results in the need of recompiling all
+// reverse-dependencies of libapt-pkg against the new SONAME.
+// Non-ABI-Breaks should only increase RELEASE number.
+// See also buildlib/libversion.mak
+#define APT_PKG_MAJOR 6
+#define APT_PKG_MINOR 0
+#define APT_PKG_RELEASE 0
+#define APT_PKG_ABI ((APT_PKG_MAJOR * 100) + APT_PKG_MINOR)
+
+/* Should be a multiple of the common page size (4096) */
+static constexpr unsigned long long APT_BUFFER_SIZE = 64 * 1024;
+
+#endif
diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc
new file mode 100644
index 0000000..0568e1c
--- /dev/null
+++ b/apt-pkg/contrib/mmap.cc
@@ -0,0 +1,504 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   MMap Class - Provides 'real' mmap or a faked mmap using read().
+
+   MMap cover class.
+
+   Some broken versions of glibc2 (libc6) have a broken definition
+   of mmap that accepts a char * -- all other systems (and libc5) use
+   void *. We can't safely do anything here that would be portable, so
+   libc6 generates warnings -- which should be errors, g++ isn't properly
+   strict.
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#define _DEFAULT_SOURCE
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/macros.h>
+#include <apt-pkg/mmap.h>
+
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+// MMap::MMap - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::MMap(FileFd &F,unsigned long Flags) : Flags(Flags), iSize(0),
+                     Base(nullptr), SyncToFd(nullptr)
+{
+   if ((Flags & NoImmMap) != NoImmMap)
+      Map(F);
+}
+									/*}}}*/
+// MMap::MMap - Constructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::MMap(unsigned long Flags) : Flags(Flags), iSize(0),
+                     Base(nullptr), SyncToFd(nullptr)
+{
+}
+									/*}}}*/
+// MMap::~MMap - Destructor						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+MMap::~MMap()
+{
+   Close();
+}
+									/*}}}*/
+// MMap::Map - Perform the mapping					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Map(FileFd &Fd)
+{
+   iSize = Fd.Size();
+
+   // Set the permissions.
+   int Prot = PROT_READ;
+   int Map = MAP_SHARED;
+   if ((Flags & ReadOnly) != ReadOnly)
+      Prot |= PROT_WRITE;
+   if ((Flags & Public) != Public)
+      Map = MAP_PRIVATE;
+   
+   if (iSize == 0)
+      return _error->Error(_("Can't mmap an empty file"));
+
+   // We can't mmap compressed fd's directly, so we need to read it completely
+   if (Fd.IsCompressed() == true)
+   {
+      if ((Flags & ReadOnly) != ReadOnly)
+	 return _error->Error("Compressed file %s can only be mapped readonly", Fd.Name().c_str());
+      Base = malloc(iSize);
+      if (unlikely(Base == nullptr))
+	 return _error->Errno("MMap-compressed-malloc", _("Couldn't make mmap of %llu bytes"), iSize);
+      SyncToFd = new FileFd();
+      if (Fd.Seek(0L) == false || Fd.Read(Base, iSize) == false)
+	 return _error->Error("Compressed file %s can't be read into mmap", Fd.Name().c_str());
+      return true;
+   }
+
+   // Map it.
+   Base = (Flags & Fallback) ? MAP_FAILED : mmap(0,iSize,Prot,Map,Fd.Fd(),0);
+   if (Base == MAP_FAILED)
+   {
+      if (errno == ENODEV || errno == EINVAL || (Flags & Fallback))
+      {
+	 // The filesystem doesn't support this particular kind of mmap.
+	 // So we allocate a buffer and read the whole file into it.
+	 if ((Flags & ReadOnly) == ReadOnly)
+	 {
+	    // for readonly, we don't need sync, so make it simple
+	    Base = malloc(iSize);
+	    if (unlikely(Base == nullptr))
+	       return _error->Errno("MMap-malloc", _("Couldn't make mmap of %llu bytes"), iSize);
+	    SyncToFd = new FileFd();
+	    return Fd.Read(Base, iSize);
+	 }
+	 // FIXME: Writing to compressed fd's ?
+	 int const dupped_fd = dup(Fd.Fd());
+	 if (dupped_fd == -1)
+	    return _error->Errno("mmap", _("Couldn't duplicate file descriptor %i"), Fd.Fd());
+
+	 Base = calloc(iSize, 1);
+	 if (unlikely(Base == nullptr))
+	    return _error->Errno("MMap-calloc", _("Couldn't make mmap of %llu bytes"), iSize);
+	 SyncToFd = new FileFd (dupped_fd);
+	 if (!SyncToFd->Seek(0L) || !SyncToFd->Read(Base, iSize))
+	    return false;
+      }
+      else
+	 return _error->Errno("MMap-mmap", _("Couldn't make mmap of %llu bytes"), iSize);
+     }
+
+   return true;
+}
+									/*}}}*/
+// MMap::Close - Close the map						/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Close(bool DoSync)
+{
+   if ((Flags & UnMapped) == UnMapped || validData() == false || iSize == 0)
+      return true;
+   
+   if (DoSync == true)
+      Sync();
+
+   if (SyncToFd != NULL)
+   {
+      free(Base);
+      delete SyncToFd;
+      SyncToFd = NULL;
+   }
+   else
+   {
+      if (munmap((char *)Base, iSize) != 0)
+	 _error->WarningE("mmap", _("Unable to close mmap"));
+   }
+
+   iSize = 0;
+   Base = 0;
+   return true;
+}
+									/*}}}*/
+// MMap::Sync - Synchronize the map with the disk			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is done in synchronous mode - the docs indicate that this will 
+   not return till all IO is complete */
+bool MMap::Sync()
+{
+   if ((Flags & UnMapped) == UnMapped)
+      return true;
+
+   if ((Flags & ReadOnly) != ReadOnly)
+   {
+      if (SyncToFd != NULL)
+      {
+	 if (!SyncToFd->Seek(0) || !SyncToFd->Write(Base, iSize))
+	    return false;
+      }
+      else
+      {
+#ifdef _POSIX_SYNCHRONIZED_IO
+	 if (msync((char *)Base, iSize, MS_SYNC) < 0)
+	    return _error->Errno("msync", _("Unable to synchronize mmap"));
+#endif
+      }
+   }
+   return true;
+}
+									/*}}}*/
+// MMap::Sync - Synchronize a section of the file to disk		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool MMap::Sync(unsigned long Start,unsigned long Stop)
+{
+   if ((Flags & UnMapped) == UnMapped)
+      return true;
+
+   if ((Flags & ReadOnly) != ReadOnly)
+   {
+      if (SyncToFd != 0)
+      {
+	 if (!SyncToFd->Seek(0) ||
+	     !SyncToFd->Write (((char *)Base)+Start, Stop-Start))
+	    return false;
+      }
+      else
+      {
+#ifdef _POSIX_SYNCHRONIZED_IO
+	 unsigned long long const PSize = sysconf(_SC_PAGESIZE);
+	 if (msync((char *)Base+(Start/PSize)*PSize, Stop - Start, MS_SYNC) < 0)
+	    return _error->Errno("msync", _("Unable to synchronize mmap"));
+#endif
+      }
+   }
+   return true;
+}
+									/*}}}*/
+
+// DynamicMMap::DynamicMMap - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+DynamicMMap::DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &Workspace,
+			 unsigned long const &Grow, unsigned long const &Limit) :
+		MMap(F,Flags | NoImmMap), Fd(&F), WorkSpace(Workspace),
+		GrowFactor(Grow), Limit(Limit)
+{
+   // disable Moveable if we don't grow
+   if (Grow == 0)
+      this->Flags &= ~Moveable;
+
+#ifndef __linux__
+   // kfreebsd doesn't have mremap, so we use the fallback
+   if ((this->Flags & Moveable) == Moveable)
+      this->Flags |= Fallback;
+#endif
+
+   unsigned long long EndOfFile = Fd->Size();
+   if (EndOfFile > WorkSpace)
+      WorkSpace = EndOfFile;
+   else if(WorkSpace > 0)
+   {
+      Fd->Seek(WorkSpace - 1);
+      char C = 0;
+      Fd->Write(&C,sizeof(C));
+   }
+   
+   Map(F);
+   iSize = EndOfFile;
+}
+									/*}}}*/
+// DynamicMMap::DynamicMMap - Constructor for a non-file backed map	/*{{{*/
+// ---------------------------------------------------------------------
+/* We try here to use mmap to reserve some space - this is much more
+   cooler than the fallback solution to simply allocate a char array
+   and could come in handy later than we are able to grow such an mmap */
+DynamicMMap::DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace,
+			 unsigned long const &Grow, unsigned long const &Limit) :
+		MMap(Flags | NoImmMap | UnMapped), Fd(0), WorkSpace(WorkSpace),
+		GrowFactor(Grow), Limit(Limit)
+{
+	// disable Moveable if we don't grow
+	if (Grow == 0)
+		this->Flags &= ~Moveable;
+
+#ifndef __linux__
+	// kfreebsd doesn't have mremap, so we use the fallback
+	if ((this->Flags & Moveable) == Moveable)
+		this->Flags |= Fallback;
+#endif
+
+#ifdef _POSIX_MAPPED_FILES
+	if ((this->Flags & Fallback) != Fallback) {
+		// Set the permissions.
+		int Prot = PROT_READ;
+#ifdef MAP_ANONYMOUS
+		int Map = MAP_PRIVATE | MAP_ANONYMOUS;
+#else
+		int Map = MAP_PRIVATE | MAP_ANON;
+#endif
+		if ((this->Flags & ReadOnly) != ReadOnly)
+			Prot |= PROT_WRITE;
+		if ((this->Flags & Public) == Public)
+#ifdef MAP_ANONYMOUS
+			Map = MAP_SHARED | MAP_ANONYMOUS;
+#else
+			Map = MAP_SHARED | MAP_ANON;
+#endif
+
+		// use anonymous mmap() to get the memory
+		Base = (unsigned char*) mmap(0, WorkSpace, Prot, Map, -1, 0);
+
+		if(Base == MAP_FAILED)
+			_error->Errno("DynamicMMap",_("Couldn't make mmap of %lu bytes"),WorkSpace);
+
+		iSize = 0;
+		return;
+	}
+#endif
+	// fallback to a static allocated space
+	Base = calloc(WorkSpace, 1);
+	iSize = 0;
+}
+									/*}}}*/
+// DynamicMMap::~DynamicMMap - Destructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* We truncate the file to the size of the memory data set */
+DynamicMMap::~DynamicMMap()
+{
+   if (Fd == 0)
+   {
+      if (validData() == false)
+	 return;
+#ifdef _POSIX_MAPPED_FILES
+      munmap(Base, WorkSpace);
+#else
+      free(Base);
+#endif
+      return;
+   }
+   
+   unsigned long long EndOfFile = iSize;
+   iSize = WorkSpace;
+   Close(false);
+   if(ftruncate(Fd->Fd(),EndOfFile) < 0)
+      _error->Errno("ftruncate", _("Failed to truncate file"));
+}  
+									/*}}}*/
+// DynamicMMap::RawAllocate - Allocate a raw chunk of unaligned space	/*{{{*/
+// ---------------------------------------------------------------------
+/* This allocates a block of memory aligned to the given size */
+unsigned long DynamicMMap::RawAllocate(unsigned long long Size,unsigned long Aln)
+{
+   unsigned long long Result = iSize;
+   if (Aln != 0)
+      Result += Aln - (iSize%Aln);
+
+   iSize = Result + Size;
+
+   // try to grow the buffer
+   while(Result + Size > WorkSpace)
+   {
+      if(!Grow())
+      {
+	 _error->Fatal(_("Dynamic MMap ran out of room. Please increase the size "
+			 "of APT::Cache-Start. Current value: %lu. (man 5 apt.conf)"), WorkSpace);
+	 return 0;
+      }
+   }
+   return Result;
+}
+									/*}}}*/
+// DynamicMMap::Allocate - Pooled aligned allocation			/*{{{*/
+// ---------------------------------------------------------------------
+/* This allocates an Item of size ItemSize so that it is aligned to its
+   size in the file. */
+unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
+{
+   if (unlikely(ItemSize == 0))
+   {
+      _error->Fatal("Can't allocate an item of size zero");
+      return 0;
+   }
+
+   // Look for a matching pool entry
+   Pool *I;
+   for (I = Pools; I != Pools + PoolCount; ++I)
+   {
+      if (I->ItemSize == ItemSize)
+	 break;
+   }
+   // No pool is allocated, use an unallocated one.
+   if (unlikely(I == Pools + PoolCount))
+   {
+      for (I = Pools; I != Pools + PoolCount; ++I)
+      {
+	 if (I->ItemSize == 0)
+	    break;
+      }
+      // Woops, we ran out, the calling code should allocate more.
+      if (I == Pools + PoolCount)
+      {
+	 _error->Error("Ran out of allocation pools");
+	 return 0;
+      }
+
+      I->ItemSize = ItemSize;
+      I->Count = 0;
+   }
+
+   unsigned long Result = 0;
+   // Out of space, allocate some more
+   if (I->Count == 0)
+   {
+      const unsigned long size = 20*1024;
+      I->Count = size/ItemSize;
+      Pool* oldPools = Pools;
+      _error->PushToStack();
+      Result = RawAllocate(size,ItemSize);
+      bool const newError = _error->PendingError();
+      _error->MergeWithStack();
+      if (Pools != oldPools)
+	 I = Pools + (I - oldPools);
+
+      // Does the allocation failed ?
+      if (Result == 0 && newError)
+	 return 0;
+      I->Start = Result;
+   }
+   else
+      Result = I->Start;
+
+   I->Count--;
+   I->Start += ItemSize;
+   return Result/ItemSize;
+}
+									/*}}}*/
+// DynamicMMap::WriteString - Write a string to the file		/*{{{*/
+// ---------------------------------------------------------------------
+/* Strings are aligned to 16 bytes */
+unsigned long DynamicMMap::WriteString(const char *String,
+				       unsigned long Len)
+{
+   if (Len == std::numeric_limits<unsigned long>::max())
+      Len = strlen(String);
+
+   _error->PushToStack();
+   unsigned long Result = RawAllocate(Len+1+sizeof(uint16_t),sizeof(uint16_t));
+   bool const newError = _error->PendingError();
+   _error->MergeWithStack();
+
+   if (Base == NULL || (Result == 0 && newError))
+      return 0;
+
+   if (Len >= std::numeric_limits<uint16_t>::max())
+      abort();
+
+   uint16_t LenToWrite = Len;
+   memcpy((char *)Base + Result, &LenToWrite, sizeof(LenToWrite));
+   Result += + sizeof(LenToWrite);
+
+   memcpy((char *)Base + Result,String,Len);
+   ((char *)Base)[Result + Len] = 0;
+   return Result;
+}
+									/*}}}*/
+// DynamicMMap::Grow - Grow the mmap					/*{{{*/
+// ---------------------------------------------------------------------
+/* This method is a wrapper around different methods to (try to) grow
+   a mmap (or our char[]-fallback). Encounterable environments:
+   1. Moveable + !Fallback + linux -> mremap with MREMAP_MAYMOVE
+   2. Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+   3. Moveable + Fallback -> realloc
+   4. !Moveable + !Fallback + linux -> mremap alone - which will fail in 99,9%
+   5. !Moveable + !Fallback + !linux -> not possible (forbidden by constructor)
+   6. !Moveable + Fallback -> not possible
+   [ While Moveable and Fallback stands for the equally named flags and
+     "linux" indicates a linux kernel instead of a freebsd kernel. ]
+   So what you can see here is, that a MMAP which want to be growable need
+   to be moveable to have a real chance but that this method will at least try
+   the nearly impossible 4 to grow it before it finally give up: Never say never. */
+bool DynamicMMap::Grow() {
+	if (Limit != 0 && WorkSpace >= Limit)
+		return _error->Error(_("Unable to increase the size of the MMap as the "
+		                       "limit of %lu bytes is already reached."), Limit);
+	if (GrowFactor <= 0)
+		return _error->Error(_("Unable to increase size of the MMap as automatic growing is disabled by user."));
+
+	unsigned long long const newSize = WorkSpace + GrowFactor;
+
+	if(Fd != 0) {
+		Fd->Seek(newSize - 1);
+		char C = 0;
+		Fd->Write(&C,sizeof(C));
+	}
+
+	unsigned long const poolOffset = Pools - ((Pool*) Base);
+
+	if ((Flags & Fallback) != Fallback) {
+#if defined(_POSIX_MAPPED_FILES) && defined(__linux__)
+   #ifdef MREMAP_MAYMOVE
+
+		if ((Flags & Moveable) == Moveable)
+			Base = mremap(Base, WorkSpace, newSize, MREMAP_MAYMOVE);
+		else
+   #endif
+			Base = mremap(Base, WorkSpace, newSize, 0);
+
+		if(Base == MAP_FAILED)
+			return false;
+#else
+		return false;
+#endif
+	} else {
+		if ((Flags & Moveable) != Moveable)
+			return false;
+
+		Base = realloc(Base, newSize);
+		if (Base == NULL)
+			return false;
+		else
+			/* Set new memory to 0 */
+			memset((char*)Base + WorkSpace, 0, newSize - WorkSpace);
+	}
+
+	Pools =(Pool*) Base + poolOffset;
+	WorkSpace = newSize;
+	return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/mmap.h b/apt-pkg/contrib/mmap.h
new file mode 100644
index 0000000..fe834d5
--- /dev/null
+++ b/apt-pkg/contrib/mmap.h
@@ -0,0 +1,120 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+   
+   MMap Class - Provides 'real' mmap or a faked mmap using read().
+
+   The purpose of this code is to provide a generic way for clients to
+   access the mmap function. In environments that do not support mmap
+   from file fd's this function will use read and normal allocated 
+   memory.
+   
+   Writing to a public mmap will always fully commit all changes when the
+   class is deleted. Ie it will rewrite the file, unless it is readonly
+
+   The DynamicMMap class is used to help the on-disk data structure 
+   generators. It provides a large allocated workspace and members
+   to allocate space from the workspace in an efficient fashion.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_MMAP_H
+#define PKGLIB_MMAP_H
+
+#include <string>
+#include <limits>
+
+#include <sys/mman.h>
+
+
+class FileFd;
+
+/* This should be a 32 bit type, larger types use too much ram and smaller
+   types are too small. Where ever possible 'unsigned long' should be used
+   instead of this internal type */
+typedef unsigned int map_ptrloc;
+
+class MMap
+{
+   protected:
+   
+   unsigned long Flags;
+   unsigned long long iSize;
+   void *Base;
+
+   // In case mmap can not be used, we keep a dup of the file
+   // descriptor that should have been mmaped so that we can write to
+   // the file in Sync().
+   FileFd *SyncToFd;
+
+   bool Map(FileFd &Fd);
+   bool Close(bool DoSync = true);
+   
+   public:
+
+   enum OpenFlags {NoImmMap = (1<<0),Public = (1<<1),ReadOnly = (1<<2),
+                   UnMapped = (1<<3), Moveable = (1<<4), Fallback = (1 << 5)};
+      
+   // Simple accessors
+   inline operator void *() {return Base;};
+   inline void *Data() {return Base;}; 
+   inline unsigned long long Size() {return iSize;};
+   inline void AddSize(unsigned long long const size) {iSize += size;};
+   inline bool validData() const { return Base != MAP_FAILED && Base != 0; };
+   
+   // File manipulators
+   bool Sync();
+   bool Sync(unsigned long Start,unsigned long Stop);
+   
+   MMap(FileFd &F,unsigned long Flags);
+   explicit MMap(unsigned long Flags);
+   virtual ~MMap();
+};
+
+class DynamicMMap : public MMap
+{
+   public:
+   
+   // This is the allocation pool structure
+   struct Pool
+   {
+      unsigned long ItemSize;
+      unsigned long Start;
+      unsigned long Count;
+   };
+   
+   protected:
+   
+   FileFd *Fd;
+   unsigned long WorkSpace;
+   unsigned long const GrowFactor;
+   unsigned long const Limit;
+   Pool *Pools;
+   unsigned int PoolCount;
+
+   bool Grow();
+   
+   public:
+
+   // Allocation
+   unsigned long RawAllocate(unsigned long long Size,unsigned long Aln = 0);
+   unsigned long Allocate(unsigned long ItemSize);
+   unsigned long WriteString(const char *String,unsigned long Len = std::numeric_limits<unsigned long>::max());
+   inline unsigned long WriteString(const std::string &S) {return WriteString(S.c_str(),S.length());};
+   void UsePools(Pool &P,unsigned int Count) {Pools = &P; PoolCount = Count;};
+   
+   DynamicMMap(FileFd &F,unsigned long Flags,unsigned long const &WorkSpace = 2*1024*1024,
+	       unsigned long const &Grow = 1024*1024, unsigned long const &Limit = 0);
+   DynamicMMap(unsigned long Flags,unsigned long const &WorkSpace = 2*1024*1024,
+	       unsigned long const &Grow = 1024*1024, unsigned long const &Limit = 0);
+   virtual ~DynamicMMap();
+};
+
+#endif
diff --git a/apt-pkg/contrib/netrc.cc b/apt-pkg/contrib/netrc.cc
new file mode 100644
index 0000000..ec694da
--- /dev/null
+++ b/apt-pkg/contrib/netrc.cc
@@ -0,0 +1,173 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   netrc file parser - returns the login and password of a give host in
+                       a specified netrc-type file
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Originally written by Daniel Stenberg, <daniel@haxx.se>, et al. and
+   placed into the Public Domain, do with it what you will.
+
+   ##################################################################### */
+									/*}}}*/
+#include <config.h>
+#include <apti18n.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <iostream>
+
+#include "netrc.h"
+
+/* Get user and password from .netrc when given a machine name */
+bool MaybeAddAuth(FileFd &NetRCFile, URI &Uri)
+{
+   if (Uri.User.empty() == false || Uri.Password.empty() == false)
+      return true;
+   if (NetRCFile.IsOpen() == false || NetRCFile.Failed())
+      return false;
+   auto const Debug = _config->FindB("Debug::Acquire::netrc", false);
+
+   std::string lookfor;
+   if (Uri.Port != 0)
+      strprintf(lookfor, "%s:%i%s", Uri.Host.c_str(), Uri.Port, Uri.Path.c_str());
+   else
+      lookfor.append(Uri.Host).append(Uri.Path);
+
+   enum
+   {
+      NO,
+      MACHINE,
+      GOOD_MACHINE,
+      LOGIN,
+      PASSWORD
+   } active_token = NO;
+   std::string line;
+   while (NetRCFile.Eof() == false || line.empty() == false)
+   {
+      bool protocolSpecified = false;
+
+      if (line.empty())
+      {
+	 if (NetRCFile.ReadLine(line) == false)
+	    break;
+	 else if (line.empty())
+	    continue;
+      }
+      auto tokenend = line.find_first_of("\t ");
+      std::string token;
+      if (tokenend != std::string::npos)
+      {
+	 token = line.substr(0, tokenend);
+	 line.erase(0, tokenend + 1);
+      }
+      else
+	 std::swap(line, token);
+      if (token.empty())
+	 continue;
+      switch (active_token)
+      {
+      case NO:
+	 if (token == "machine")
+	    active_token = MACHINE;
+	 break;
+      case MACHINE:
+	 // If token contains a protocol: Check it first, and strip it away if
+	 // it matches. If it does not match, ignore this stanza.
+	 // If there is no protocol, only allow https protocols.
+	 protocolSpecified = token.find("://") != std::string::npos;
+	 if (protocolSpecified)
+	 {
+	    if (not APT::String::Startswith(token, Uri.Access + "://"))
+	    {
+	       active_token = NO;
+	       break;
+	    }
+	    token.erase(0, Uri.Access.length() + 3);
+	 }
+
+	 if (token.find('/') == std::string::npos)
+	 {
+	    if (Uri.Port != 0 && Uri.Host == token)
+	       active_token = GOOD_MACHINE;
+	    else if (lookfor.compare(0, lookfor.length() - Uri.Path.length(), token) == 0)
+	       active_token = GOOD_MACHINE;
+	    else
+	       active_token = NO;
+	 }
+	 else
+	 {
+	    if (APT::String::Startswith(lookfor, token))
+	       active_token = GOOD_MACHINE;
+	    else
+	       active_token = NO;
+	 }
+
+	 if (active_token == GOOD_MACHINE && not protocolSpecified)
+	 {
+	    if (Uri.Access != "https" && Uri.Access != "tor+https")
+	    {
+	       _error->Warning(_("%s: Credentials for %s match, but the protocol is not encrypted. Annotate with %s:// to use."), NetRCFile.Name().c_str(), token.c_str(), Uri.Access.c_str());
+	       active_token = NO;
+	    }
+	 }
+	 break;
+      case GOOD_MACHINE:
+	 if (token == "login")
+	    active_token = LOGIN;
+	 else if (token == "password")
+	    active_token = PASSWORD;
+	 else if (token == "machine")
+	 {
+	    if (Debug)
+	       std::clog << "MaybeAddAuth: Found matching host adding '" << Uri.User << "' and '" << Uri.Password << "' for "
+			 << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+	    return true;
+	 }
+	 break;
+      case LOGIN:
+	 std::swap(Uri.User, token);
+	 active_token = GOOD_MACHINE;
+	 break;
+      case PASSWORD:
+	 std::swap(Uri.Password, token);
+	 active_token = GOOD_MACHINE;
+	 break;
+      }
+   }
+   if (active_token == GOOD_MACHINE)
+   {
+      if (Debug)
+	 std::clog << "MaybeAddAuth: Found matching host adding '" << Uri.User << "' and '" << Uri.Password << "' for "
+		   << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+      return true;
+   }
+   else if (active_token == NO)
+   {
+      if (Debug)
+	 std::clog << "MaybeAddAuth: Found no matching host for "
+		   << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+      return true;
+   }
+   else if (Debug)
+   {
+      std::clog << "MaybeAddAuth: Found no matching host (syntax error: token:";
+      switch (active_token)
+      {
+	 case NO: std::clog << "NO"; break;
+	 case MACHINE: std::clog << "MACHINE"; break;
+	 case GOOD_MACHINE: std::clog << "GOOD_MACHINE"; break;
+	 case LOGIN: std::clog << "LOGIN"; break;
+	 case PASSWORD: std::clog << "PASSWORD"; break;
+      }
+      std::clog << ") for " << (std::string)Uri << " from " << NetRCFile.Name() << std::endl;
+   }
+   return false;
+}
diff --git a/apt-pkg/contrib/netrc.h b/apt-pkg/contrib/netrc.h
new file mode 100644
index 0000000..2d202d1
--- /dev/null
+++ b/apt-pkg/contrib/netrc.h
@@ -0,0 +1,30 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   netrc file parser - returns the login and password of a give host in
+                       a specified netrc-type file
+
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   Originally written by Daniel Stenberg, <daniel@haxx.se>, et al. and
+   placed into the Public Domain, do with it what you will.
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef NETRC_H
+#define NETRC_H
+
+#include <string>
+
+#include <apt-pkg/macros.h>
+
+
+
+class URI;
+class FileFd;
+
+APT_PUBLIC bool MaybeAddAuth(FileFd &NetRCFile, URI &Uri);
+#endif
diff --git a/apt-pkg/contrib/progress.cc b/apt-pkg/contrib/progress.cc
new file mode 100644
index 0000000..eb688b9
--- /dev/null
+++ b/apt-pkg/contrib/progress.cc
@@ -0,0 +1,229 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   OpProgress - Operation Progress
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/progress.h>
+
+#include <cmath>
+#include <chrono>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <stdio.h>
+#include <sys/time.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+
+// OpProgress::OpProgress - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+OpProgress::OpProgress() : Current(0), Total(0), Size(0), SubTotal(1), 
+                           LastPercent(0), Percent(0)
+{
+   memset(&LastTime,0,sizeof(LastTime));
+}
+									/*}}}*/
+// OpProgress::Progress - Sub progress with no state change		/*{{{*/
+// ---------------------------------------------------------------------
+/* Current is the Base Overall progress in units of Total. Cur is the sub
+   progress in units of SubTotal. Size is a scaling factor that says what
+   percent of Total SubTotal is. */
+void OpProgress::Progress(unsigned long long Cur)
+{
+   if (Total == 0 || Size == 0 || SubTotal == 0)
+      Percent = 0;
+   else
+      Percent = (Current + Cur/((double)SubTotal)*Size)*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::OverallProgress - Set the overall progress		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpProgress::OverallProgress(unsigned long long Current, unsigned long long Total,
+	  			 unsigned long long Size,const string &Op)
+{
+   this->Current = Current;
+   this->Total = Total;
+   this->Size = Size;
+   this->Op = Op;
+   SubOp = string();
+   if (Total == 0)
+      Percent = 0;
+   else
+      Percent = Current*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::SubProgress - Set the sub progress state			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpProgress::SubProgress(unsigned long long SubTotal,const string &Op,
+			     float const Percent)
+{
+   this->SubTotal = SubTotal;
+   if (Op.empty() == false)
+      SubOp = Op;
+   if (Total == 0 || Percent == 0)
+      this->Percent = 0;
+   else if (Percent != -1)
+      this->Percent = this->Current += (Size*Percent)/SubTotal;
+   else
+      this->Percent = Current*100.0/Total;
+   Update();
+}
+									/*}}}*/
+// OpProgress::CheckChange - See if the display should be updated	/*{{{*/
+// ---------------------------------------------------------------------
+/* Progress calls are made so frequently that if every one resulted in 
+   an update the display would be swamped and the system much slower.
+   This provides an upper bound on the update rate. */
+bool OpProgress::CheckChange(float Interval)
+{
+   // For absolute progress, we assume every call is relevant.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      return true;
+   // New major progress indication
+   if (Op != LastOp)
+   {
+      MajorChange = true;
+      LastOp = Op;
+      return true;
+   }
+   MajorChange = false;
+
+   if (SubOp != LastSubOp)
+   {
+      LastSubOp = SubOp;
+      return true;
+   }
+   
+   if (std::lround(LastPercent) == std::lround(Percent))
+      return false;
+
+   LastPercent = Percent;
+   
+   if (Interval == 0)
+      return false;
+   
+   // Check time delta
+   auto const Now = std::chrono::steady_clock::now().time_since_epoch();
+   auto const Now_sec = std::chrono::duration_cast<std::chrono::seconds>(Now);
+   auto const Now_usec = std::chrono::duration_cast<std::chrono::microseconds>(Now - Now_sec);
+   struct timeval NowTime = { static_cast<time_t>(Now_sec.count()), static_cast<suseconds_t>(Now_usec.count()) };
+
+   std::chrono::duration<decltype(Interval)> Delta =
+      std::chrono::seconds(NowTime.tv_sec - LastTime.tv_sec) +
+      std::chrono::microseconds(NowTime.tv_usec - LastTime.tv_usec);
+
+   if (Delta.count() < Interval)
+      return false;
+   LastTime = NowTime;
+   return true;
+}
+									/*}}}*/
+// OpTextProgress::OpTextProgress - Constructor				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+OpTextProgress::OpTextProgress(Configuration &Config) :
+                               NoUpdate(false), NoDisplay(false), LastLen(0)
+{
+   if (Config.FindI("quiet",0) >= 1 || Config.FindB("quiet::NoUpdate", false) == true)
+      NoUpdate = true;
+   if (Config.FindI("quiet",0) >= 2 || Config.FindB("quiet::NoProgress", false) == true)
+      NoDisplay = true;
+}
+									/*}}}*/
+// OpTextProgress::Done - Clean up the display				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpTextProgress::Done()
+{
+   if (NoUpdate == false && OldOp.empty() == false)
+   {
+      char S[300];
+      if (_error->PendingError() == true)
+	 snprintf(S,sizeof(S),_("%c%s... Error!"),'\r',OldOp.c_str());
+      else
+	 snprintf(S,sizeof(S),_("%c%s... Done"),'\r',OldOp.c_str());
+      Write(S);
+      cout << endl;
+      OldOp = string();
+   }
+
+   if (NoUpdate == true && NoDisplay == false && OldOp.empty() == false)
+   {
+      OldOp = string();
+      cout << endl;
+   }
+}
+									/*}}}*/
+// OpTextProgress::Update - Simple text spinner				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void OpTextProgress::Update()
+{
+   if (CheckChange((NoUpdate == true?0:0.7)) == false)
+      return;
+   
+   // No percent spinner
+   if (NoUpdate == true)
+   {
+      if (MajorChange == false)
+	 return;
+      if (NoDisplay == false)
+      {
+	 if (OldOp.empty() == false)
+	    cout << endl;
+	 OldOp = "a";
+	 cout << Op << _("...") << flush;
+      }
+      
+      return;
+   }
+
+   // Erase the old text and 'log' the event
+   char S[300];
+   if (MajorChange == true && OldOp.empty() == false)
+   {
+      snprintf(S,sizeof(S),"\r%s",OldOp.c_str());
+      Write(S);
+      cout << endl;
+   }
+
+   // Print the spinner. Absolute progress shows us a time progress.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false) && Total != -1llu)
+      snprintf(S, sizeof(S), _("%c%s... %llu/%llus"), '\r', Op.c_str(), Current, Total);
+   else if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      snprintf(S, sizeof(S), _("%c%s... %llus"), '\r', Op.c_str(), Current);
+   else
+      snprintf(S, sizeof(S), _("%c%s... %u%%"), '\r', Op.c_str(), (unsigned int)Percent);
+   Write(S);
+
+   OldOp = Op;
+}
+									/*}}}*/
+// OpTextProgress::Write - Write the progress string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This space fills the end to overwrite the previous text */
+void OpTextProgress::Write(const char *S)
+{
+   cout << S;
+   for (unsigned int I = strlen(S); I < LastLen; I++)
+      cout << ' ';
+   cout << '\r' << flush;
+   LastLen = strlen(S);
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/progress.h b/apt-pkg/contrib/progress.h
new file mode 100644
index 0000000..d6a698a
--- /dev/null
+++ b/apt-pkg/contrib/progress.h
@@ -0,0 +1,87 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   OpProgress - Operation Progress
+   
+   This class allows lengthy operations to communicate their progress 
+   to the GUI. The progress model is simple and is not designed to handle
+   the complex case of the multi-activity acquire class.
+   
+   The model is based on the concept of an overall operation consisting
+   of a series of small sub operations. Each sub operation has it's own
+   completion status and the overall operation has it's completion status.
+   The units of the two are not mixed and are completely independent.
+   
+   The UI is expected to subclass this to provide the visuals to the user.
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PROGRESS_H
+#define PKGLIB_PROGRESS_H
+
+#include <apt-pkg/macros.h>
+#include <string>
+#include <sys/time.h>
+
+
+class Configuration;
+class APT_PUBLIC OpProgress
+{
+   friend class OpTextProgress;
+   unsigned long long Current;
+   unsigned long long Total;
+   unsigned long long Size;
+   unsigned long long SubTotal;
+   float LastPercent;
+   
+   // Change reduction code
+   struct timeval LastTime;
+   std::string LastOp;
+   std::string LastSubOp;
+   
+   protected:
+   
+   std::string Op;
+   std::string SubOp;
+   float Percent;
+   
+   bool MajorChange;
+   
+   bool CheckChange(float Interval = 0.7);		    
+   virtual void Update() {};
+   
+   public:
+   
+   void Progress(unsigned long long Current);
+   void SubProgress(unsigned long long SubTotal, const std::string &Op = "", float const Percent = -1);
+   void OverallProgress(unsigned long long Current,unsigned long long Total,
+			unsigned long long Size,const std::string &Op);
+   virtual void Done() {};
+   
+   OpProgress();
+   virtual ~OpProgress() {};
+};
+
+class APT_PUBLIC OpTextProgress : public OpProgress
+{
+   protected:
+
+   std::string OldOp;
+   bool NoUpdate;
+   bool NoDisplay;
+   unsigned long LastLen;
+   virtual void Update() APT_OVERRIDE;
+   void Write(const char *S);
+   
+   public:
+
+   virtual void Done() APT_OVERRIDE;
+   
+   explicit OpTextProgress(bool NoUpdate = false) : NoUpdate(NoUpdate),
+                NoDisplay(false), LastLen(0) {};
+   explicit OpTextProgress(Configuration &Config);
+   virtual ~OpTextProgress() {Done();};
+};
+
+#endif
diff --git a/apt-pkg/contrib/proxy.cc b/apt-pkg/contrib/proxy.cc
new file mode 100644
index 0000000..a99f44f
--- /dev/null
+++ b/apt-pkg/contrib/proxy.cc
@@ -0,0 +1,99 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Proxy - Proxy related functions
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "proxy.h"
+									/*}}}*/
+
+// AutoDetectProxy - auto detect proxy					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+static std::vector<std::string> CompatibleProxies(URI const &URL)
+{
+   if (URL.Access == "http" || URL.Access == "https")
+      return {"http", "https", "socks5h"};
+   return {URL.Access};
+}
+
+bool AutoDetectProxy(URI &URL)
+{
+   // we support both http/https debug options
+   bool Debug = _config->FindB("Debug::Acquire::"+URL.Access,false);
+
+   // the user already explicitly set a proxy for this host
+   if(_config->Find("Acquire::"+URL.Access+"::proxy::"+URL.Host, "") != "")
+      return true;
+
+   // option is "Acquire::http::Proxy-Auto-Detect" but we allow the old
+   // name without the dash ("-")
+   std::string AutoDetectProxyCmd = _config->Find("Acquire::"+URL.Access+"::Proxy-Auto-Detect",
+                                      _config->Find("Acquire::"+URL.Access+"::ProxyAutoDetect"));
+
+   if (AutoDetectProxyCmd.empty())
+      return true;
+
+   if (Debug)
+      std::clog << "Using auto proxy detect command: " << AutoDetectProxyCmd << std::endl;
+
+   if (faccessat(AT_FDCWD, AutoDetectProxyCmd.c_str(), R_OK | X_OK, AT_EACCESS) != 0)
+      return _error->Errno("access", "ProxyAutoDetect command '%s' can not be executed!", AutoDetectProxyCmd.c_str());
+
+   std::string const urlstring = URL;
+   std::vector<const char *> Args;
+   Args.push_back(AutoDetectProxyCmd.c_str());
+   Args.push_back(urlstring.c_str());
+   Args.push_back(nullptr);
+   FileFd PipeFd;
+   pid_t Child;
+   if (Popen(&Args[0], PipeFd, Child, FileFd::ReadOnly, false, true) == false)
+      return _error->Error("ProxyAutoDetect command '%s' failed!", AutoDetectProxyCmd.c_str());
+   char buf[512];
+   bool const goodread = PipeFd.ReadLine(buf, sizeof(buf)) != nullptr;
+   PipeFd.Close();
+   if (ExecWait(Child, "ProxyAutoDetect") == false)
+      return false;
+   // no output means the detector has no idea which proxy to use
+   // and apt will use the generic proxy settings
+   if (goodread == false)
+      return true;
+   auto const cleanedbuf = _strstrip(buf);
+   // We warn about this as the implementor probably meant to use DIRECT instead
+   if (cleanedbuf[0] == '\0')
+   {
+      _error->Warning("ProxyAutoDetect command returned an empty line");
+      return true;
+   }
+
+   if (Debug)
+      std::clog << "auto detect command returned: '" << cleanedbuf << "'" << std::endl;
+
+   auto compatibleTypes = CompatibleProxies(URL);
+   bool compatible = strcmp(cleanedbuf, "DIRECT") == 0 ||
+		     compatibleTypes.end() != std::find_if(compatibleTypes.begin(),
+							   compatibleTypes.end(), [cleanedbuf](std::string &compat) {
+							      return strstr(cleanedbuf, compat.c_str()) == cleanedbuf;
+							   });
+
+   if (compatible)
+      _config->Set("Acquire::"+URL.Access+"::proxy::"+URL.Host, cleanedbuf);
+
+   return true;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/proxy.h b/apt-pkg/contrib/proxy.h
new file mode 100644
index 0000000..f6d70ea
--- /dev/null
+++ b/apt-pkg/contrib/proxy.h
@@ -0,0 +1,16 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+   
+   Proxy - Proxy operations
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef PKGLIB_PROXY_H
+#define PKGLIB_PROXY_H
+
+class URI;
+APT_PUBLIC bool AutoDetectProxy(URI &URL);
+
+
+#endif
diff --git a/apt-pkg/contrib/srvrec.cc b/apt-pkg/contrib/srvrec.cc
new file mode 100644
index 0000000..3eb5f1d
--- /dev/null
+++ b/apt-pkg/contrib/srvrec.cc
@@ -0,0 +1,211 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   SRV record support
+
+   ##################################################################### */
+									/*}}}*/
+#include <config.h>
+
+#include <netdb.h>
+
+#include <arpa/nameser.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <resolv.h>
+#include <time.h>
+
+#include <algorithm>
+#include <memory>
+#include <tuple>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/strutl.h>
+
+#include "srvrec.h"
+
+bool SrvRec::operator==(SrvRec const &other) const
+{
+   return (std::tie(target, priority, weight, port) ==
+           std::tie(other.target, other.priority, other.weight, other.port));
+}
+
+bool GetSrvRecords(std::string host, int port, std::vector<SrvRec> &Result)
+{
+   // try SRV only for hostnames, not for IP addresses
+   {
+      struct in_addr addr4;
+      struct in6_addr addr6;
+      if (inet_pton(AF_INET, host.c_str(), &addr4) == 1 ||
+	  inet_pton(AF_INET6, host.c_str(), &addr6) == 1)
+	 return true;
+   }
+
+   std::string target;
+   int res;
+   struct servent s_ent_buf;
+   struct servent *s_ent = nullptr;
+   std::vector<char> buf(1024);
+
+   res = getservbyport_r(htons(port), "tcp", &s_ent_buf, buf.data(), buf.size(), &s_ent);
+   if (res != 0 || s_ent == nullptr)
+      return false;
+
+   strprintf(target, "_%s._tcp.%s", s_ent->s_name, host.c_str());
+   return GetSrvRecords(target, Result);
+}
+
+bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result)
+{
+   unsigned char answer[PACKETSZ];
+   int answer_len, compressed_name_len;
+   int answer_count;
+#if __RES >= 19991006
+   struct __res_state res;
+
+   if (res_ninit(&res) != 0)
+      return _error->Errno("res_init", "Failed to init resolver");
+
+   // Close on return
+   std::shared_ptr<void> guard(&res, res_nclose);
+
+   answer_len = res_nquery(&res, name.c_str(), C_IN, T_SRV, answer, sizeof(answer));
+#else
+   if (res_init() != 0)
+      return _error->Errno("res_init", "Failed to init resolver");
+
+   answer_len = res_query(name.c_str(), C_IN, T_SRV, answer, sizeof(answer));
+#endif //__RES >= 19991006
+   if (answer_len == -1)
+      return false;
+   if (answer_len < (int)sizeof(HEADER))
+      return _error->Warning("Not enough data from res_query (%i)", answer_len);
+
+   // check the header
+   HEADER *header = (HEADER*)answer;
+   if (header->rcode != NOERROR)
+      return _error->Warning("res_query returned rcode %i", header->rcode);
+   answer_count = ntohs(header->ancount);
+   if (answer_count <= 0)
+      return _error->Warning("res_query returned no answers (%i) ", answer_count);
+
+   // skip the header
+   compressed_name_len = dn_skipname(answer+sizeof(HEADER), answer+answer_len);
+   if(compressed_name_len < 0)
+      return _error->Warning("dn_skipname failed %i", compressed_name_len);
+
+   // pt points to the first answer record, go over all of them now
+   unsigned char *pt = answer+sizeof(HEADER)+compressed_name_len+QFIXEDSZ;
+   while ((int)Result.size() < answer_count && pt < answer+answer_len)
+   {
+      u_int16_t type, klass, priority, weight, port, dlen;
+      char buf[MAXDNAME];
+
+      compressed_name_len = dn_skipname(pt, answer+answer_len);
+      if (compressed_name_len < 0)
+         return _error->Warning("dn_skipname failed (2): %i",
+                                compressed_name_len);
+      pt += compressed_name_len;
+      if (((answer+answer_len) - pt) < 16)
+         return _error->Warning("packet too short");
+
+      // extract the data out of the result buffer
+      #define extract_u16(target, p) target = *p++ << 8; target |= *p++;
+
+      extract_u16(type, pt);
+      if(type != T_SRV)
+         return _error->Warning("Unexpected type excepted %x != %x",
+                                T_SRV, type);
+      extract_u16(klass, pt);
+      if(klass != C_IN)
+         return _error->Warning("Unexpected class excepted %x != %x",
+                                C_IN, klass);
+      pt += 4;  // ttl
+      extract_u16(dlen, pt);
+      extract_u16(priority, pt);
+      extract_u16(weight, pt);
+      extract_u16(port, pt);
+
+      #undef extract_u16
+
+      compressed_name_len = dn_expand(answer, answer+answer_len, pt, buf, sizeof(buf));
+      if(compressed_name_len < 0)
+         return _error->Warning("dn_expand failed %i", compressed_name_len);
+      pt += compressed_name_len;
+
+      // add it to our class
+      Result.emplace_back(buf, priority, weight, port);
+   }
+
+   // implement load balancing as specified in RFC-2782
+
+   // sort them by priority
+   std::stable_sort(Result.begin(), Result.end());
+
+   if (_config->FindB("Debug::Acquire::SrvRecs", false))
+      for(auto const &R : Result)
+	 std::cerr << "SrvRecs: got " << R.target
+		   << " prio: " << R.priority
+		   << " weight: " << R.weight
+		   << '\n';
+
+   return true;
+}
+
+SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs)
+{
+   // FIXME: instead of the simplistic shuffle below use the algorithm
+   //        described in rfc2782 (with weights)
+   //        and figure out how the weights need to be adjusted if
+   //        a host refuses connections
+
+#if 0  // all code below is only needed for the weight adjusted selection 
+   // assign random number ranges
+   int prev_weight = 0;
+   int prev_priority = 0;
+   for(std::vector<SrvRec>::iterator I = Result.begin();
+      I != Result.end(); ++I)
+   {
+      if(prev_priority != I->priority)
+         prev_weight = 0;
+      I->random_number_range_start = prev_weight;
+      I->random_number_range_end = prev_weight + I->weight;
+      prev_weight = I->random_number_range_end;
+      prev_priority = I->priority;
+
+      if (_config->FindB("Debug::Acquire::SrvRecs", false) == true)
+         std::cerr << "SrvRecs: got " << I->target
+                   << " prio: " << I->priority
+                   << " weight: " << I->weight
+                   << std::endl;
+   }
+
+   // go over the code in reverse order and note the max random range
+   int max = 0;
+   prev_priority = 0;
+   for(std::vector<SrvRec>::iterator I = Result.end();
+      I != Result.begin(); --I)
+   {
+      if(prev_priority != I->priority)
+         max = I->random_number_range_end;
+      I->random_number_range_max = max;
+   }
+#endif
+
+   // shuffle in a very simplistic way for now (equal weights)
+   std::vector<SrvRec>::iterator I = Recs.begin();
+   std::vector<SrvRec>::iterator const J = std::find_if(Recs.begin(), Recs.end(),
+	 [&I](SrvRec const &J) { return I->priority != J.priority; });
+
+   // clock seems random enough.
+   I += std::max(static_cast<clock_t>(0), clock()) % std::distance(I, J);
+   SrvRec const selected = std::move(*I);
+   Recs.erase(I);
+
+   if (_config->FindB("Debug::Acquire::SrvRecs", false) == true)
+      std::cerr << "PopFromSrvRecs: selecting " << selected.target << std::endl;
+
+   return selected;
+}
diff --git a/apt-pkg/contrib/srvrec.h b/apt-pkg/contrib/srvrec.h
new file mode 100644
index 0000000..1e981d3
--- /dev/null
+++ b/apt-pkg/contrib/srvrec.h
@@ -0,0 +1,57 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   SRV record support
+
+   ##################################################################### */
+									/*}}}*/
+#ifndef SRVREC_H
+#define SRVREC_H
+
+#include <string>
+#include <vector>
+#include <arpa/nameser.h>
+#include <sys/types.h>
+
+#include <apt-pkg/macros.h>
+
+class APT_PUBLIC SrvRec
+{
+ public:
+   std::string target;
+   u_int16_t priority;
+   u_int16_t weight;
+   u_int16_t port;
+
+   // each server is assigned a interval [start, end] in the space of [0, max]
+   int random_number_range_start;
+   int random_number_range_end;
+   int random_number_range_max;
+
+   bool operator<(SrvRec const &other) const {
+      return this->priority < other.priority;
+   }
+   bool operator==(SrvRec const &other) const;
+
+   SrvRec(std::string const Target, u_int16_t const Priority,
+	 u_int16_t const Weight, u_int16_t const Port) :
+      target(Target), priority(Priority), weight(Weight), port(Port),
+      random_number_range_start(0), random_number_range_end(0),
+      random_number_range_max(0) {}
+};
+
+/** \brief Get SRV records from host/port (builds the query string internally) 
+ */
+APT_PUBLIC bool GetSrvRecords(std::string name, std::vector<SrvRec> &Result);
+
+/** \brief Get SRV records for query string like: _http._tcp.example.com
+ */
+APT_PUBLIC bool GetSrvRecords(std::string host, int port, std::vector<SrvRec> &Result);
+
+/** \brief Pop a single SRV record from the vector of SrvRec taking
+ *         priority and weight into account
+ */
+APT_PUBLIC SrvRec PopFromSrvRecs(std::vector<SrvRec> &Recs);
+
+#endif
diff --git a/apt-pkg/contrib/string_view.h b/apt-pkg/contrib/string_view.h
new file mode 100644
index 0000000..04f6ff1
--- /dev/null
+++ b/apt-pkg/contrib/string_view.h
@@ -0,0 +1,163 @@
+/*
+ * Basic implementation of string_view
+ *
+ * (C) 2015 Julian Andres Klode <jak@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#if !defined(APT_STRINGVIEW_H)
+#define APT_STRINGVIEW_H
+#include <apt-pkg/macros.h>
+#include <string>
+#include <string.h>
+
+namespace APT {
+
+/**
+ * \brief Simple subset of std::string_view from C++17
+ *
+ * This is an internal implementation of the subset of std::string_view
+ * used by APT. It is not meant to be used in programs, only inside the
+ * library for performance critical paths.
+ */
+class StringView {
+    const char *data_;
+    size_t size_;
+
+public:
+    static constexpr size_t npos = static_cast<size_t>(-1);
+    static_assert(APT::StringView::npos == std::string::npos, "npos values are different");
+
+    /* Constructors */
+    constexpr StringView() : data_(""), size_(0) {}
+    constexpr StringView(const char *data, size_t size) : data_(data), size_(size) {}
+
+    StringView(const char *data) : data_(data), size_(strlen(data)) {}
+    StringView(std::string const & str): data_(str.data()), size_(str.size()) {}
+
+    /* Modifiers */
+    void remove_prefix(size_t n) { data_ += n; size_ -= n; }
+    void remove_suffix(size_t n) { size_ -= n; }
+    void clear() { size_ = 0; }
+
+    /* Viewers */
+    constexpr StringView substr(size_t pos, size_t n = npos) const {
+        return StringView(data_ + pos, n > (size_ - pos) ? (size_ - pos) : n);
+    }
+
+    size_t find(int c, size_t pos) const {
+       if (pos == 0)
+	  return find(c);
+       size_t const found = substr(pos).find(c);
+       if (found == npos)
+	  return npos;
+       return pos + found;
+    }
+    size_t find(int c) const {
+        const char *found = static_cast<const char*>(memchr(data_, c, size_));
+
+        if (found == NULL)
+            return npos;
+
+        return found - data_;
+    }
+
+    size_t rfind(int c, size_t pos) const {
+       if (pos == npos)
+	  return rfind(c);
+       return APT::StringView(data_, pos).rfind(c);
+    }
+    size_t rfind(int c) const {
+        const char *found = static_cast<const char*>(memrchr(data_, c, size_));
+
+        if (found == NULL)
+            return npos;
+
+        return found - data_;
+    }
+
+    size_t find(APT::StringView const needle) const {
+       if (needle.empty())
+	  return npos;
+       if (needle.length() == 1)
+	  return find(*needle.data());
+       size_t found = 0;
+       while ((found = find(*needle.data(), found)) != npos) {
+	  if (compare(found, needle.length(), needle) == 0)
+	     return found;
+	  ++found;
+       }
+       return found;
+    }
+    size_t find(APT::StringView const needle, size_t pos) const {
+       if (pos == 0)
+	  return find(needle);
+       size_t const found = substr(pos).find(needle);
+       if (found == npos)
+	  return npos;
+       return pos + found;
+    }
+
+    /* Conversions */
+    std::string to_string() const {
+        return std::string(data_, size_);
+    }
+
+    /* Comparisons */
+    int compare(size_t pos, size_t n, StringView other) const {
+        return substr(pos, n).compare(other);
+    }
+
+    int compare(StringView other) const {
+        int res;
+
+        res = memcmp(data_, other.data_, std::min(size_, other.size_));
+        if (res != 0)
+            return res;
+        if (size_ == other.size_)
+            return res;
+
+        return (size_ > other.size_) ? 1 : -1;
+    }
+
+    /* Optimization: If size not equal, string cannot be equal */
+    bool operator ==(StringView other) const { return size_ == other.size_ && compare(other) == 0; }
+    bool operator !=(StringView other) const { return !(*this == other); }
+
+    /* Accessors */
+    constexpr bool empty() const { return size_ == 0; }
+    constexpr const char* data() const { return data_; }
+    constexpr const char* begin() const { return data_; }
+    constexpr const char* end() const { return data_ + size_; }
+    constexpr char operator [](size_t i) const { return data_[i]; }
+    constexpr size_t size() const { return size_; }
+    constexpr size_t length() const { return size_; }
+};
+
+/**
+ * \brief Faster comparison for string views (compare size before data)
+ *
+ * Still stable, but faster than the normal ordering. */
+static inline int StringViewCompareFast(StringView a, StringView b) {
+    if (a.size() != b.size())
+        return a.size() - b.size();
+
+    return memcmp(a.data(), b.data(), a.size());
+}
+
+static constexpr inline APT::StringView operator""_sv(const char *data, size_t size)
+{
+   return APT::StringView(data, size);
+}
+}
+
+inline bool operator ==(const char *other, APT::StringView that);
+inline bool operator ==(const char *other, APT::StringView that) { return that.operator==(other); }
+inline bool operator ==(std::string const &other, APT::StringView that);
+inline bool operator ==(std::string const &other, APT::StringView that) { return that.operator==(other); }
+
+#endif
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
new file mode 100644
index 0000000..67100f1
--- /dev/null
+++ b/apt-pkg/contrib/strutl.cc
@@ -0,0 +1,1820 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   String Util - Some useful string functions.
+
+   These have been collected from here and there to do all sorts of useful
+   things to strings. They are useful in file parsers, URI handlers and
+   especially in APT methods.   
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@gpu.srv.ualberta.ca>
+   
+   ##################################################################### */
+									/*}}}*/
+// Includes								/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <array>
+#include <iomanip>
+#include <limits>
+#include <locale>
+#include <sstream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include <ctype.h>
+#include <errno.h>
+#include <iconv.h>
+#include <regex.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+// Strip - Remove white space from the front and back of a string       /*{{{*/
+// ---------------------------------------------------------------------
+namespace APT {
+   namespace String {
+std::string Strip(const std::string &str)
+{
+   // ensure we have at least one character
+   if (str.empty() == true)
+      return str;
+
+   char const * const s = str.c_str();
+   size_t start = 0;
+   for (; isspace(s[start]) != 0; ++start)
+      ; // find the first not-space
+
+   // string contains only whitespaces
+   if (s[start] == '\0')
+      return "";
+
+   size_t end = str.length() - 1;
+   for (; isspace(s[end]) != 0; --end)
+      ; // find the last not-space
+
+   return str.substr(start, end - start + 1);
+}
+
+bool Endswith(const std::string &s, const std::string &end)
+{
+   if (end.size() > s.size())
+      return false;
+   return (s.compare(s.size() - end.size(), end.size(), end) == 0);
+}
+
+bool Startswith(const std::string &s, const std::string &start)
+{
+   if (start.size() > s.size())
+      return false;
+   return (s.compare(0, start.size(), start) == 0);
+}
+
+std::string Join(std::vector<std::string> list, const std::string &sep)
+{
+   std::ostringstream oss;
+   for (auto it = list.begin(); it != list.end(); it++)
+   {
+      if (it != list.begin()) oss << sep;
+      oss << *it;
+   }
+   return oss.str();
+}
+
+// Returns string display length honoring multi-byte characters
+size_t DisplayLength(StringView str)
+{
+   size_t len = 0;
+
+   const char *p = str.data();
+   const char *const end = str.end();
+
+   mbstate_t state{};
+   while (p < end)
+   {
+      wchar_t wch;
+      size_t res = mbrtowc(&wch, p, end - p, &state);
+      switch (res)
+      {
+      case 0:
+         // Null wide character (i.e. L'\0') - stop
+         p = end;
+         break;
+
+      case static_cast<size_t>(-1):
+         // Byte sequence is invalid. Assume that it's
+         // a single-byte single-width character.
+         len += 1;
+         p += 1;
+
+         // state is undefined in this case - reset it
+         state = {};
+
+         break;
+
+      case static_cast<size_t>(-2):
+         // Byte sequence is too short. Assume that it's
+         // an incomplete single-width character and stop.
+         len += 1;
+         p = end;
+         break;
+
+      default:
+         len += wcwidth(wch);
+         p += res;
+      }
+   }
+
+   return len;
+}
+
+}
+}
+									/*}}}*/
+// UTF8ToCodeset - Convert some UTF-8 string for some codeset   	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is handy to use before display some information for enduser  */
+bool UTF8ToCodeset(const char *codeset, const string &orig, string *dest)
+{
+  iconv_t cd;
+  const char *inbuf;
+  char *inptr, *outbuf;
+  size_t insize, bufsize;
+  dest->clear();
+
+  cd = iconv_open(codeset, "UTF-8");
+  if (cd == (iconv_t)(-1)) {
+     // Something went wrong
+     if (errno == EINVAL)
+	_error->Error("conversion from 'UTF-8' to '%s' not available",
+               codeset);
+     else
+	perror("iconv_open");
+     
+     return false;
+  }
+
+  insize = bufsize = orig.size();
+  inbuf = orig.data();
+  inptr = (char *)inbuf;
+  outbuf = new char[bufsize];
+  size_t lastError = -1;
+
+  while (insize != 0)
+  {
+     char *outptr = outbuf;
+     size_t outsize = bufsize;
+     size_t const err = iconv(cd, &inptr, &insize, &outptr, &outsize);
+     dest->append(outbuf, outptr - outbuf);
+     if (err == (size_t)(-1))
+     {
+	switch (errno)
+	{
+	case EILSEQ:
+	   insize--;
+	   inptr++;
+	   // replace a series of unknown multibytes with a single "?"
+	   if (lastError != insize) {
+	      lastError = insize - 1;
+	      dest->append("?");
+	   }
+	   break;
+	case EINVAL:
+	   insize = 0;
+	   break;
+	case E2BIG:
+	   if (outptr == outbuf)
+	   {
+	      bufsize *= 2;
+	      delete[] outbuf;
+	      outbuf = new char[bufsize];
+	   }
+	   break;
+	}
+     }
+  }
+
+  delete[] outbuf;
+  
+  iconv_close(cd);
+
+  return true;
+}
+									/*}}}*/
+// strstrip - Remove white space from the front and back of a string	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is handy to use when parsing a file. It also removes \n's left 
+   over from fgets and company */
+char *_strstrip(char *String)
+{
+   for (;*String != 0 && (*String == ' ' || *String == '\t'); String++);
+
+   if (*String == 0)
+      return String;
+   return _strrstrip(String);
+}
+									/*}}}*/
+// strrstrip - Remove white space from the back of a string	/*{{{*/
+// ---------------------------------------------------------------------
+char *_strrstrip(char *String)
+{
+   char *End = String + strlen(String) - 1;
+   for (;End != String - 1 && (*End == ' ' || *End == '\t' || *End == '\n' ||
+			       *End == '\r'); End--);
+   End++;
+   *End = 0;
+   return String;
+}
+									/*}}}*/
+// strtabexpand - Converts tabs into 8 spaces				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+char *_strtabexpand(char *String,size_t Len)
+{
+   for (char *I = String; I != I + Len && *I != 0; I++)
+   {
+      if (*I != '\t')
+	 continue;
+      if (I + 8 > String + Len)
+      {
+	 *I = 0;
+	 return String;
+      }
+
+      /* Assume the start of the string is 0 and find the next 8 char
+         division */
+      int Len;
+      if (String == I)
+	 Len = 1;
+      else
+	 Len = 8 - ((String - I) % 8);
+      Len -= 2;
+      if (Len <= 0)
+      {
+	 *I = ' ';
+	 continue;
+      }
+      
+      memmove(I + Len,I + 1,strlen(I) + 1);
+      for (char *J = I; J + Len != I; *I = ' ', I++);
+   }
+   return String;
+}
+									/*}}}*/
+// ParseQuoteWord - Parse a single word out of a string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This grabs a single word, converts any % escaped characters to their
+   proper values and advances the pointer. Double quotes are understood
+   and striped out as well. This is for URI/URL parsing. It also can 
+   understand [] brackets.*/
+bool ParseQuoteWord(const char *&String,string &Res)
+{
+   // Skip leading whitespace
+   const char *C = String;
+   for (; *C == ' '; C++)
+      ;
+   if (*C == 0)
+      return false;
+   
+   // Jump to the next word
+   for (;*C != 0 && isspace(*C) == 0; C++)
+   {
+      if (*C == '"')
+      {
+	 C = strchr(C + 1, '"');
+	 if (C == NULL)
+	    return false;
+      }
+      if (*C == '[')
+      {
+	 C = strchr(C + 1, ']');
+	 if (C == NULL)
+	    return false;
+      }
+   }
+
+   // Now de-quote characters
+   Res.clear();
+   Res.reserve(C - String);
+   char Tmp[3];
+   const char *Start = String;
+   while (Start != C)
+   {
+      if (*Start == '%' && Start + 2 < C &&
+	  isxdigit(Start[1]) && isxdigit(Start[2]))
+      {
+	 Tmp[0] = Start[1];
+	 Tmp[1] = Start[2];
+	 Tmp[2] = 0;
+	 Res.push_back(static_cast<char>(strtol(Tmp, 0, 16)));
+	 Start += 3;
+	 continue;
+      }
+      if (*Start != '"')
+	 Res.push_back(*Start);
+      ++Start;
+   }
+
+   // Skip ending white space
+   for (; isspace(*C) != 0; C++)
+      ;
+   String = C;
+   return true;
+}
+									/*}}}*/
+// ParseCWord - Parses a string like a C "" expression			/*{{{*/
+// ---------------------------------------------------------------------
+/* This expects a series of space separated strings enclosed in ""'s. 
+   It concatenates the ""'s into a single string. */
+bool ParseCWord(const char *&String,string &Res)
+{
+   // Skip leading whitespace
+   const char *C = String;
+   for (; *C == ' '; C++)
+      ;
+   if (*C == 0)
+      return false;
+
+   Res.clear();
+   Res.reserve(strlen(String));
+   for (; *C != 0; ++C)
+   {
+      if (*C == '"')
+      {
+	 for (C++; *C != 0 && *C != '"'; C++)
+	    Res.push_back(*C);
+
+	 if (*C == 0)
+	    return false;
+
+	 continue;
+      }
+
+      if (C != String && isspace(*C) != 0 && isspace(C[-1]) != 0)
+	 continue;
+      if (isspace(*C) == 0)
+	 return false;
+      Res.push_back(' ');
+   }
+   String = C;
+   return true;
+}
+									/*}}}*/
+// QuoteString - Convert a string into quoted from			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string QuoteString(const string &Str, const char *Bad)
+{
+   std::stringstream Res;
+   for (string::const_iterator I = Str.begin(); I != Str.end(); ++I)
+   {
+      if (strchr(Bad,*I) != 0 || isprint(*I) == 0 ||
+	  *I == 0x25 || // percent '%' char
+	  *I <= 0x20 || *I >= 0x7F) // control chars
+      {
+	 ioprintf(Res, "%%%02hhx", *I);
+      }
+      else
+	 Res << *I;
+   }
+   return Res.str();
+}
+									/*}}}*/
+// DeQuoteString - Convert a string from quoted from                    /*{{{*/
+// ---------------------------------------------------------------------
+/* This undoes QuoteString */
+string DeQuoteString(const string &Str)
+{
+   return DeQuoteString(Str.begin(),Str.end());
+}
+string DeQuoteString(string::const_iterator const &begin,
+			string::const_iterator const &end)
+{
+   string Res;
+   for (string::const_iterator I = begin; I != end; ++I)
+   {
+      if (*I == '%' && I + 2 < end &&
+	  isxdigit(I[1]) && isxdigit(I[2]))
+      {
+	 char Tmp[3];
+	 Tmp[0] = I[1];
+	 Tmp[1] = I[2];
+	 Tmp[2] = 0;
+	 Res += (char)strtol(Tmp,0,16);
+	 I += 2;
+	 continue;
+      }
+      else
+	 Res += *I;
+   }
+   return Res;   
+}
+
+                                                                        /*}}}*/
+// SizeToStr - Convert a long into a human readable size		/*{{{*/
+// ---------------------------------------------------------------------
+/* A max of 4 digits are shown before conversion to the next highest unit. 
+   The max length of the string will be 5 chars unless the size is > 10
+   YottaBytes (E24) */
+string SizeToStr(double Size)
+{
+   double ASize;
+   if (Size >= 0)
+      ASize = Size;
+   else
+      ASize = -1*Size;
+
+   /* bytes, KiloBytes, MegaBytes, GigaBytes, TeraBytes, PetaBytes, 
+      ExaBytes, ZettaBytes, YottaBytes */
+   char Ext[] = {'\0','k','M','G','T','P','E','Z','Y'};
+   int I = 0;
+   while (I <= 8)
+   {
+      if (ASize < 100 && I != 0)
+      {
+	 std::string S;
+	 strprintf(S, "%'.1f %c", ASize, Ext[I]);
+	 return S;
+      }
+
+      if (ASize < 10000)
+      {
+	 std::string S;
+	 strprintf(S, "%'.0f %c", ASize, Ext[I]);
+	 return S;
+      }
+      ASize /= 1000.0;
+      I++;
+   }
+   return "";
+}
+									/*}}}*/
+// TimeToStr - Convert the time into a string				/*{{{*/
+// ---------------------------------------------------------------------
+/* Converts a number of seconds to a hms format */
+string TimeToStr(unsigned long Sec)
+{
+   std::string S;
+   if (Sec > 60*60*24)
+   {
+      //TRANSLATOR: d means days, h means hours, min means minutes, s means seconds
+      strprintf(S,_("%lid %lih %limin %lis"),Sec/60/60/24,(Sec/60/60) % 24,(Sec/60) % 60,Sec % 60);
+   }
+   else if (Sec > 60*60)
+   {
+      //TRANSLATOR: h means hours, min means minutes, s means seconds
+      strprintf(S,_("%lih %limin %lis"),Sec/60/60,(Sec/60) % 60,Sec % 60);
+   }
+   else if (Sec > 60)
+   {
+      //TRANSLATOR: min means minutes, s means seconds
+      strprintf(S,_("%limin %lis"),Sec/60,Sec % 60);
+   }
+   else
+   {
+      //TRANSLATOR: s means seconds
+      strprintf(S,_("%lis"),Sec);
+   }
+   return S;
+}
+									/*}}}*/
+// SubstVar - Substitute a string for another string			/*{{{*/
+// ---------------------------------------------------------------------
+/* This replaces all occurrences of Subst with Contents in Str. */
+string SubstVar(const string &Str,const string &Subst,const string &Contents)
+{
+   if (Subst.empty() == true)
+      return Str;
+
+   string::size_type Pos = 0;
+   string::size_type OldPos = 0;
+   string Temp;
+
+   while (OldPos < Str.length() &&
+	  (Pos = Str.find(Subst,OldPos)) != string::npos)
+   {
+      if (OldPos != Pos)
+	 Temp.append(Str, OldPos, Pos - OldPos);
+      if (Contents.empty() == false)
+	 Temp.append(Contents);
+      OldPos = Pos + Subst.length();
+   }
+
+   if (OldPos == 0)
+      return Str;
+
+   if (OldPos >= Str.length())
+      return Temp;
+
+   Temp.append(Str, OldPos, string::npos);
+   return Temp;
+}
+string SubstVar(string Str,const struct SubstVar *Vars)
+{
+   for (; Vars->Subst != 0; Vars++)
+      Str = SubstVar(Str,Vars->Subst,*Vars->Contents);
+   return Str;
+}
+									/*}}}*/
+// OutputInDepth - return a string with separator multiplied with depth /*{{{*/
+// ---------------------------------------------------------------------
+/* Returns a string with the supplied separator depth + 1 times in it */
+std::string OutputInDepth(const unsigned long Depth, const char* Separator)
+{
+   std::string output = "";
+   for(unsigned long d=Depth+1; d > 0; d--)
+      output.append(Separator);
+   return output;
+}
+									/*}}}*/
+// URItoFileName - Convert the uri into a unique file name		/*{{{*/
+// ---------------------------------------------------------------------
+/* This converts a URI into a safe filename. It quotes all unsafe characters
+   and converts / to _ and removes the scheme identifier. The resulting
+   file name should be unique and never occur again for a different file */
+string URItoFileName(const string &URI)
+{
+   // Nuke 'sensitive' items
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   U.Access.clear();
+   
+   // "\x00-\x20{}|\\\\^\\[\\]<>\"\x7F-\xFF";
+   string NewURI = QuoteString(U,"\\|{}[]<>\"^~_=!@#$%^&*");
+   replace(NewURI.begin(),NewURI.end(),'/','_');
+   return NewURI;
+}
+									/*}}}*/
+// Base64Encode - Base64 Encoding routine for short strings		/*{{{*/
+// ---------------------------------------------------------------------
+/* This routine performs a base64 transformation on a string. It was ripped
+   from wget and then patched and bug fixed.
+ 
+   This spec can be found in rfc2045 */
+string Base64Encode(const string &S)
+{
+   // Conversion table.
+   static char tbl[64] = {'A','B','C','D','E','F','G','H',
+   			  'I','J','K','L','M','N','O','P',
+                          'Q','R','S','T','U','V','W','X',
+                          'Y','Z','a','b','c','d','e','f',
+                          'g','h','i','j','k','l','m','n',
+                          'o','p','q','r','s','t','u','v',
+                          'w','x','y','z','0','1','2','3',
+                          '4','5','6','7','8','9','+','/'};
+   
+   // Pre-allocate some space
+   string Final;
+   Final.reserve((4*S.length() + 2)/3 + 2);
+
+   /* Transform the 3x8 bits to 4x6 bits, as required by
+      base64.  */
+   for (string::const_iterator I = S.begin(); I < S.end(); I += 3)
+   {
+      uint8_t Bits[3] = {0,0,0};
+      Bits[0] = I[0];
+      if (I + 1 < S.end())
+	 Bits[1] = I[1];
+      if (I + 2 < S.end())
+	 Bits[2] = I[2];
+
+      Final += tbl[Bits[0] >> 2];
+      Final += tbl[((Bits[0] & 3) << 4) + (Bits[1] >> 4)];
+      
+      if (I + 1 >= S.end())
+	 break;
+      
+      Final += tbl[((Bits[1] & 0xf) << 2) + (Bits[2] >> 6)];
+      
+      if (I + 2 >= S.end())
+	 break;
+      
+      Final += tbl[Bits[2] & 0x3f];
+   }
+
+   /* Apply the padding elements, this tells how many bytes the remote
+      end should discard */
+   if (S.length() % 3 == 2)
+      Final += '=';
+   if (S.length() % 3 == 1)
+      Final += "==";
+   
+   return Final;
+}
+									/*}}}*/
+// stringcmp - Arbitrary string compare					/*{{{*/
+// ---------------------------------------------------------------------
+/* This safely compares two non-null terminated strings of arbitrary 
+   length */
+int stringcmp(const char *A,const char *AEnd,const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+
+#if __GNUC__ >= 3
+int stringcmp(string::const_iterator A,string::const_iterator AEnd,
+	      const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+int stringcmp(string::const_iterator A,string::const_iterator AEnd,
+	      string::const_iterator B,string::const_iterator BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (*A != *B)
+	 break;
+   
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (*A < *B)
+      return -1;
+   return 1;
+}
+#endif
+									/*}}}*/
+// stringcasecmp - Arbitrary case insensitive string compare		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+int stringcasecmp(const char *A,const char *AEnd,const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+#if __GNUC__ >= 3
+int stringcasecmp(string::const_iterator A,string::const_iterator AEnd,
+		  const char *B,const char *BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+int stringcasecmp(string::const_iterator A,string::const_iterator AEnd,
+		  string::const_iterator B,string::const_iterator BEnd)
+{
+   for (; A != AEnd && B != BEnd; A++, B++)
+      if (tolower_ascii(*A) != tolower_ascii(*B))
+	 break;
+
+   if (A == AEnd && B == BEnd)
+      return 0;
+   if (A == AEnd)
+      return 1;
+   if (B == BEnd)
+      return -1;
+   if (tolower_ascii(*A) < tolower_ascii(*B))
+      return -1;
+   return 1;
+}
+#endif
+									/*}}}*/
+// LookupTag - Lookup the value of a tag in a tagged string		/*{{{*/
+// ---------------------------------------------------------------------
+/* The format is like those used in package files and the method
+   communication system */
+std::string LookupTag(const std::string &Message, const char *TagC, const char *Default)
+{
+   std::string tag = std::string("\n") + TagC + ":";
+   if (Default == nullptr)
+      Default = "";
+   if (Message.length() < tag.length())
+      return Default;
+   std::transform(tag.begin(), tag.end(), tag.begin(), tolower_ascii);
+   auto valuestart = Message.cbegin();
+   // maybe the message starts directly with tag
+   if (Message[tag.length() - 2] == ':')
+   {
+      std::string lowstart = std::string("\n") + Message.substr(0, tag.length() - 1);
+      std::transform(lowstart.begin(), lowstart.end(), lowstart.begin(), tolower_ascii);
+      if (lowstart == tag)
+	 valuestart = std::next(valuestart, tag.length() - 1);
+   }
+   // the tag is somewhere in the message
+   if (valuestart == Message.cbegin())
+   {
+      auto const tagbegin = std::search(Message.cbegin(), Message.cend(), tag.cbegin(), tag.cend(),
+					[](char const a, char const b) { return tolower_ascii(a) == b; });
+      if (tagbegin == Message.cend())
+	 return Default;
+      valuestart = std::next(tagbegin, tag.length());
+   }
+   auto const is_whitespace = [](char const c) { return isspace_ascii(c) != 0 && c != '\n'; };
+   auto const is_newline = [](char const c) { return c == '\n'; };
+   std::string result;
+   valuestart = std::find_if_not(valuestart, Message.cend(), is_whitespace);
+   // is the first line of the value empty?
+   if (valuestart != Message.cend() && *valuestart == '\n')
+   {
+      valuestart = std::next(valuestart);
+      if (valuestart != Message.cend() && *valuestart == ' ')
+	 valuestart = std::next(valuestart);
+   }
+   // extract the value over multiple lines removing trailing whitespace
+   while (valuestart < Message.cend())
+   {
+      auto const linebreak = std::find_if(valuestart, Message.cend(), is_newline);
+      auto valueend = std::prev(linebreak);
+      // skip spaces at the end of the line
+      while (valueend > valuestart && is_whitespace(*valueend))
+	 valueend = std::prev(valueend);
+      // append found line to result
+      {
+	 std::string tmp(valuestart, std::next(valueend));
+	 if (tmp != ".")
+	 {
+	    if (result.empty())
+	       result.assign(std::move(tmp));
+	    else
+	       result.append(tmp);
+	 }
+      }
+      // see if the value is multiline
+      if (linebreak == Message.cend())
+	 break;
+      valuestart = std::next(linebreak);
+      if (valuestart == Message.cend() || *valuestart != ' ')
+	 break;
+      result.append("\n");
+      // skip the space leading a multiline (Keep all other whitespaces in the value)
+      valuestart = std::next(valuestart);
+   }
+   auto const valueend = result.find_last_not_of("\n");
+   if (valueend == std::string::npos)
+      result.clear();
+   else
+      result.erase(valueend + 1);
+   return result;
+}
+									/*}}}*/
+// StringToBool - Converts a string into a boolean			/*{{{*/
+// ---------------------------------------------------------------------
+/* This inspects the string to see if it is true or if it is false and
+   then returns the result. Several variants on true/false are checked. */
+int StringToBool(const string &Text,int Default)
+{
+   char *ParseEnd;
+   int Res = strtol(Text.c_str(),&ParseEnd,0);
+   // ensure that the entire string was converted by strtol to avoid
+   // failures on "apt-cache show -a 0ad" where the "0" is converted
+   const char *TextEnd = Text.c_str()+Text.size();
+   if (ParseEnd == TextEnd && Res >= 0 && Res <= 1)
+      return Res;
+   
+   // Check for positives
+   if (strcasecmp(Text.c_str(),"no") == 0 ||
+       strcasecmp(Text.c_str(),"false") == 0 ||
+       strcasecmp(Text.c_str(),"without") == 0 ||
+       strcasecmp(Text.c_str(),"off") == 0 ||
+       strcasecmp(Text.c_str(),"disable") == 0)
+      return 0;
+   
+   // Check for negatives
+   if (strcasecmp(Text.c_str(),"yes") == 0 ||
+       strcasecmp(Text.c_str(),"true") == 0 ||
+       strcasecmp(Text.c_str(),"with") == 0 ||
+       strcasecmp(Text.c_str(),"on") == 0 ||
+       strcasecmp(Text.c_str(),"enable") == 0)
+      return 1;
+   
+   return Default;
+}
+									/*}}}*/
+// TimeRFC1123 - Convert a time_t into RFC1123 format			/*{{{*/
+// ---------------------------------------------------------------------
+/* This converts a time_t into a string time representation that is
+   year 2000 compliant and timezone neutral */
+string TimeRFC1123(time_t Date, bool const NumericTimezone)
+{
+   struct tm Conv;
+   if (gmtime_r(&Date, &Conv) == NULL)
+      return "";
+
+   auto const posix = std::locale::classic();
+   std::ostringstream datestr;
+   datestr.imbue(posix);
+   APT::StringView const fmt("%a, %d %b %Y %H:%M:%S");
+   std::use_facet<std::time_put<char>>(posix).put(
+                    std::ostreambuf_iterator<char>(datestr),
+                    datestr, ' ', &Conv, fmt.data(), fmt.data() + fmt.size());
+   if (NumericTimezone)
+      datestr << " +0000";
+   else
+      datestr << " GMT";
+   return datestr.str();
+}
+									/*}}}*/
+// ReadMessages - Read messages from the FD				/*{{{*/
+// ---------------------------------------------------------------------
+/* This pulls full messages from the input FD into the message buffer. 
+   It assumes that messages will not pause during transit so no
+   fancy buffering is used.
+
+   In particular: this reads blocks from the input until it believes
+   that it's run out of input text.  Each block is terminated by a
+   double newline ('\n' followed by '\n').
+ */
+bool ReadMessages(int Fd, vector<string> &List)
+{
+   char Buffer[64000];
+   // Represents any left-over from the previous iteration of the
+   // parse loop.  (i.e., if a message is split across the end
+   // of the buffer, it goes here)
+   string PartialMessage;
+
+   do {
+      int const Res = read(Fd, Buffer, sizeof(Buffer));
+      if (Res < 0 && errno == EINTR)
+	 continue;
+
+      // process we read from has died
+      if (Res == 0)
+	 return false;
+
+      // No data
+#if EAGAIN != EWOULDBLOCK
+      if (Res < 0 && (errno == EAGAIN || errno == EWOULDBLOCK))
+#else
+      if (Res < 0 && errno == EAGAIN)
+#endif
+	 return true;
+      if (Res < 0)
+	 return false;
+
+      // extract the message(s) from the buffer
+      char const *Start = Buffer;
+      char const * const End = Buffer + Res;
+
+      char const * NL = (char const *) memchr(Start, '\n', End - Start);
+      if (NL == NULL)
+      {
+	 // end of buffer: store what we have so far and read new data in
+	 PartialMessage.append(Start, End - Start);
+	 Start = End;
+      }
+      else
+	 ++NL;
+
+      if (PartialMessage.empty() == false && Start < End)
+      {
+	 // if we start with a new line, see if the partial message we have ended with one
+	 // so that we properly detect records ending between two read() runs
+	 // cases are: \n|\n  ,  \r\n|\r\n  and  \r\n\r|\n
+	 // the case \r|\n\r\n is handled by the usual double-newline handling
+	 if ((NL - Start) == 1 || ((NL - Start) == 2 && *Start == '\r'))
+	 {
+	    if (APT::String::Endswith(PartialMessage, "\n") || APT::String::Endswith(PartialMessage, "\r\n\r"))
+	    {
+	       PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+	       List.push_back(PartialMessage);
+	       PartialMessage.clear();
+	       while (NL < End && (*NL == '\n' || *NL == '\r')) ++NL;
+	       Start = NL;
+	    }
+	 }
+      }
+
+      while (Start < End) {
+	 char const * NL2 = (char const *) memchr(NL, '\n', End - NL);
+	 if (NL2 == NULL)
+	 {
+	    // end of buffer: store what we have so far and read new data in
+	    PartialMessage.append(Start, End - Start);
+	    break;
+	 }
+	 ++NL2;
+
+	 // did we find a double newline?
+	 if ((NL2 - NL) == 1 || ((NL2 - NL) == 2 && *NL == '\r'))
+	 {
+	    PartialMessage.append(Start, NL2 - Start);
+	    PartialMessage.erase(PartialMessage.find_last_not_of("\r\n") + 1);
+	    List.push_back(PartialMessage);
+	    PartialMessage.clear();
+	    while (NL2 < End && (*NL2 == '\n' || *NL2 == '\r')) ++NL2;
+	    Start = NL2;
+	 }
+	 NL = NL2;
+      }
+
+      // we have read at least one complete message and nothing left
+      if (PartialMessage.empty() == true)
+	 return true;
+
+      if (WaitFd(Fd) == false)
+	 return false;
+   } while (true);
+}
+									/*}}}*/
+// MonthConv - Converts a month string into a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This was lifted from the boa webserver which lifted it from 'wn-v1.07'
+   Made it a bit more robust with a few tolower_ascii though. */
+static int MonthConv(char const * const Month)
+{
+   switch (tolower_ascii(*Month)) 
+   {
+      case 'a':
+      return tolower_ascii(Month[1]) == 'p'?3:7;
+      case 'd':
+      return 11;
+      case 'f':
+      return 1;
+      case 'j':
+      if (tolower_ascii(Month[1]) == 'a')
+	 return 0;
+      return tolower_ascii(Month[2]) == 'n'?5:6;
+      case 'm':
+      return tolower_ascii(Month[2]) == 'r'?2:4;
+      case 'n':
+      return 10;
+      case 'o':
+      return 9;
+      case 's':
+      return 8;
+
+      // Pretend it is January..
+      default:
+      return 0;
+   }   
+}
+									/*}}}*/
+// timegm - Internal timegm if the gnu version is not available		/*{{{*/
+// ---------------------------------------------------------------------
+/* Converts struct tm to time_t, assuming the data in tm is UTC rather
+   than local timezone (mktime assumes the latter).
+
+   This function is a nonstandard GNU extension that is also present on
+   the BSDs and maybe other systems. For others we follow the advice of
+   the manpage of timegm and use his portable replacement. */
+#ifndef HAVE_TIMEGM
+static time_t timegm(struct tm *t)
+{
+   char *tz = getenv("TZ");
+   setenv("TZ", "", 1);
+   tzset();
+   time_t ret = mktime(t);
+   if (tz)
+      setenv("TZ", tz, 1);
+   else
+      unsetenv("TZ");
+   tzset();
+   return ret;
+}
+#endif
+									/*}}}*/
+// RFC1123StrToTime - Converts an HTTP1.1 full date strings into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* tries to parses a full date as specified in RFC7231 §7.1.1.1
+   with one exception: HTTP/1.1 valid dates need to have GMT as timezone.
+   As we encounter dates from UTC or with a numeric timezone in other places,
+   we allow them here to to be able to reuse the method. Either way, a date
+   must be in UTC or parsing will fail. Previous implementations of this
+   method used to ignore the timezone and assume always UTC. */
+bool RFC1123StrToTime(std::string const &str,time_t &time)
+{
+   unsigned short day = 0;
+   signed int year = 0; // yes, Y23K problem – we going to worry then…
+   std::string weekday, month, datespec, timespec, zone;
+   std::istringstream ss(str);
+   auto const &posix = std::locale::classic();
+   ss.imbue(posix);
+   ss >> weekday;
+   // we only superficially check weekday, mostly to avoid accepting localized
+   // weekdays here and take only its length to decide which datetime format we
+   // encounter here. The date isn't stored.
+   std::transform(weekday.begin(), weekday.end(), weekday.begin(), ::tolower);
+   std::array<char const * const, 7> c_weekdays = {{ "sun", "mon", "tue", "wed", "thu", "fri", "sat" }};
+   if (std::find(c_weekdays.begin(), c_weekdays.end(), weekday.substr(0,3)) == c_weekdays.end())
+      return false;
+
+   switch (weekday.length())
+   {
+   case 4:
+      // Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
+      if (weekday[3] != ',')
+	 return false;
+      ss >> day >> month >> year >> timespec >> zone;
+      break;
+   case 3:
+      // Sun Nov  6 08:49:37 1994 ; ANSI C's asctime() format
+      ss >> month >> day >> timespec >> year;
+      zone = "UTC";
+      break;
+   case 0:
+   case 1:
+   case 2:
+      return false;
+   default:
+      // Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
+      if (weekday[weekday.length() - 1] != ',')
+	 return false;
+      ss >> datespec >> timespec >> zone;
+      auto const expldate = VectorizeString(datespec, '-');
+      if (expldate.size() != 3)
+	 return false;
+      try {
+	 size_t pos;
+	 day = std::stoi(expldate[0], &pos);
+	 if (pos != expldate[0].length())
+	    return false;
+	 year = 1900 + std::stoi(expldate[2], &pos);
+	 if (pos != expldate[2].length())
+	    return false;
+	 strprintf(datespec, "%.4d-%.2d-%.2d", year, MonthConv(expldate[1].c_str()) + 1, day);
+      } catch (...) {
+         return false;
+      }
+      break;
+   }
+
+   if (ss.fail() || ss.bad() || !ss.eof())
+      return false;
+
+   if (zone != "GMT" && zone != "UTC" && zone != "Z") // RFC 822
+   {
+      // numeric timezones as a should of RFC 1123 and generally preferred
+      try {
+	 size_t pos;
+	 auto const z = std::stoi(zone, &pos);
+	 if (z != 0 || pos != zone.length())
+	    return false;
+      } catch (...) {
+	 return false;
+      }
+   }
+
+   if (datespec.empty())
+   {
+      if (month.empty())
+	 return false;
+      strprintf(datespec, "%.4d-%.2d-%.2d", year, MonthConv(month.c_str()) + 1, day);
+   }
+
+   std::string const datetime = datespec + ' ' + timespec;
+   struct tm Tm;
+   if (strptime(datetime.c_str(), "%Y-%m-%d %H:%M:%S", &Tm) == nullptr)
+      return false;
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
+// FTPMDTMStrToTime - Converts a ftp modification date into a time_t	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool FTPMDTMStrToTime(const char* const str,time_t &time)
+{
+   struct tm Tm;
+   // MDTM includes no whitespaces but recommend and ignored by strptime
+   if (strptime(str, "%Y %m %d %H %M %S", &Tm) == NULL)
+      return false;
+
+   time = timegm(&Tm);
+   return true;
+}
+									/*}}}*/
+// StrToNum - Convert a fixed length string to a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the crazy fixed length string headers in
+   tar and ar files. */
+bool StrToNum(const char *Str,unsigned long &Res,unsigned Len,unsigned Base)
+{
+   unsigned long long BigRes;
+   if (not StrToNum(Str, BigRes, Len, Base))
+      return false;
+
+   if (std::numeric_limits<unsigned long>::max() < BigRes)
+      return false;
+
+   Res = BigRes;
+   return true;
+}
+									/*}}}*/
+// StrToNum - Convert a fixed length string to a number			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the crazy fixed length string headers in
+   tar and ar files. */
+bool StrToNum(const char *Str,unsigned long long &Res,unsigned Len,unsigned Base)
+{
+   char S[30];
+   if (Len >= sizeof(S))
+      return false;
+   memcpy(S,Str,Len);
+   S[Len] = 0;
+
+   // All spaces is a zero
+   Res = 0;
+   unsigned I;
+   for (I = 0; S[I] == ' '; ++I);
+   if (S[I] == 0)
+      return true;
+   if (S[I] == '-')
+      return false;
+
+   char *End;
+   errno = 0;
+   Res = strtoull(S,&End,Base);
+   return not (End == S || errno != 0);
+}
+									/*}}}*/
+
+// Base256ToNum - Convert a fixed length binary to a number             /*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the 256bit encoded fixed length fields in
+   tar files */
+bool Base256ToNum(const char *Str,unsigned long long &Res,unsigned int Len)
+{
+   if ((Str[0] & 0x80) == 0)
+      return false;
+   else
+   {
+      Res = Str[0] & 0x7F;
+      for(unsigned int i = 1; i < Len; ++i)
+         Res = (Res<<8) + Str[i];
+      return true;
+   }
+}
+									/*}}}*/
+// Base256ToNum - Convert a fixed length binary to a number             /*{{{*/
+// ---------------------------------------------------------------------
+/* This is used in decoding the 256bit encoded fixed length fields in
+   tar files */
+bool Base256ToNum(const char *Str,unsigned long &Res,unsigned int Len)
+{
+   unsigned long long Num = 0;
+   bool rc;
+
+   rc = Base256ToNum(Str, Num, Len);
+   // rudimentary check for overflow (Res = ulong, Num = ulonglong)
+   Res = Num;
+   if (Res != Num)
+      return false;
+
+   return rc;
+}
+									/*}}}*/
+// HexDigit - Convert a hex character into an integer			/*{{{*/
+// ---------------------------------------------------------------------
+/* Helper for Hex2Num */
+static int HexDigit(int c)
+{   
+   if (c >= '0' && c <= '9')
+      return c - '0';
+   if (c >= 'a' && c <= 'f')
+      return c - 'a' + 10;
+   if (c >= 'A' && c <= 'F')
+      return c - 'A' + 10;
+   return -1;
+}
+									/*}}}*/
+// Hex2Num - Convert a long hex number into a buffer			/*{{{*/
+// ---------------------------------------------------------------------
+/* The length of the buffer must be exactly 1/2 the length of the string. */
+bool Hex2Num(const APT::StringView Str,unsigned char *Num,unsigned int Length)
+{
+   if (Str.length() != Length*2)
+      return false;
+   
+   // Convert each digit. We store it in the same order as the string
+   int J = 0;
+   for (auto I = Str.begin(); I != Str.end();J++, I += 2)
+   {
+      int first_half = HexDigit(I[0]);
+      int second_half;
+      if (first_half < 0)
+	 return false;
+      
+      second_half = HexDigit(I[1]);
+      if (second_half < 0)
+	 return false;
+      Num[J] = first_half << 4;
+      Num[J] += second_half;
+   }
+   
+   return true;
+}
+									/*}}}*/
+// TokSplitString - Split a string up by a given token			/*{{{*/
+// ---------------------------------------------------------------------
+/* This is intended to be a faster splitter, it does not use dynamic
+   memories. Input is changed to insert nulls at each token location. */
+bool TokSplitString(char Tok,char *Input,char **List,
+		    unsigned long ListMax)
+{
+   // Strip any leading spaces
+   char *Start = Input;
+   char *Stop = Start + strlen(Start);
+   for (; *Start != 0 && isspace(*Start) != 0; Start++);
+
+   unsigned long Count = 0;
+   char *Pos = Start;
+   while (Pos != Stop)
+   {
+      // Skip to the next Token
+      for (; Pos != Stop && *Pos != Tok; Pos++);
+      
+      // Back remove spaces
+      char *End = Pos;
+      for (; End > Start && (End[-1] == Tok || isspace(End[-1]) != 0); End--);
+      *End = 0;
+      
+      List[Count++] = Start;
+      if (Count >= ListMax)
+      {
+	 List[Count-1] = 0;
+	 return false;
+      }
+      
+      // Advance pos
+      for (; Pos != Stop && (*Pos == Tok || isspace(*Pos) != 0 || *Pos == 0); Pos++);
+      Start = Pos;
+   }
+   
+   List[Count] = 0;
+   return true;
+}
+									/*}}}*/
+// VectorizeString - Split a string up into a vector of strings		/*{{{*/
+// ---------------------------------------------------------------------
+/* This can be used to split a given string up into a vector, so the
+   propose is the same as in the method above and this one is a bit slower
+   also, but the advantage is that we have an iteratable vector */
+vector<string> VectorizeString(string const &haystack, char const &split)
+{
+   vector<string> exploded;
+   if (haystack.empty() == true)
+      return exploded;
+   string::const_iterator start = haystack.begin();
+   string::const_iterator end = start;
+   do {
+      for (; end != haystack.end() && *end != split; ++end);
+      exploded.push_back(string(start, end));
+      start = end + 1;
+   } while (end != haystack.end() && (++end) != haystack.end());
+   return exploded;
+}
+									/*}}}*/
+// StringSplit - split a string into a string vector by token		/*{{{*/
+// ---------------------------------------------------------------------
+/* See header for details.
+ */
+vector<string> StringSplit(std::string const &s, std::string const &sep,
+                           unsigned int maxsplit)
+{
+   vector<string> split;
+   size_t start, pos;
+
+   // no separator given, this is bogus
+   if(sep.size() == 0)
+      return split;
+
+   start = pos = 0;
+   while (pos != string::npos)
+   {
+      pos = s.find(sep, start);
+      split.push_back(s.substr(start, pos-start));
+      
+      // if maxsplit is reached, the remaining string is the last item
+      if(split.size() >= maxsplit)
+      {
+         split[split.size()-1] = s.substr(start);
+         break;
+      }
+      start = pos+sep.size();
+   }
+   return split;
+}
+									/*}}}*/
+// RegexChoice - Simple regex list/list matcher				/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+unsigned long RegexChoice(RxChoiceList *Rxs,const char **ListBegin,
+		      const char **ListEnd)
+{
+   for (RxChoiceList *R = Rxs; R->Str != 0; R++)
+      R->Hit = false;
+
+   unsigned long Hits = 0;
+   for (; ListBegin < ListEnd; ++ListBegin)
+   {
+      // Check if the name is a regex
+      const char *I;
+      bool Regex = true;
+      for (I = *ListBegin; *I != 0; I++)
+	 if (*I == '.' || *I == '?' || *I == '*' || *I == '|')
+	    break;
+      if (*I == 0)
+	 Regex = false;
+	 
+      // Compile the regex pattern
+      regex_t Pattern;
+      if (Regex == true)
+	 if (regcomp(&Pattern,*ListBegin,REG_EXTENDED | REG_ICASE |
+		     REG_NOSUB) != 0)
+	    Regex = false;
+	 
+      // Search the list
+      bool Done = false;
+      for (RxChoiceList *R = Rxs; R->Str != 0; R++)
+      {
+	 if (R->Str[0] == 0)
+	    continue;
+	 
+	 if (strcasecmp(R->Str,*ListBegin) != 0)
+	 {
+	    if (Regex == false)
+	       continue;
+	    if (regexec(&Pattern,R->Str,0,0,0) != 0)
+	       continue;
+	 }
+	 Done = true;
+	 
+	 if (R->Hit == false)
+	    Hits++;
+	 
+	 R->Hit = true;
+      }
+      
+      if (Regex == true)
+	 regfree(&Pattern);
+      
+      if (Done == false)
+	 _error->Warning(_("Selection %s not found"),*ListBegin);
+   }
+   
+   return Hits;
+}
+									/*}}}*/
+// {str,io}printf - C format string outputter to C++ strings/iostreams	/*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to make the internationalization strings easier to translate
+   and to allow reordering of parameters */
+bool iovprintf(std::ostream &out, const char *format,
+		      va_list &args, ssize_t &size) {
+   auto S = std::unique_ptr<char,decltype(&free)>{static_cast<char*>(malloc(size)), &free};
+   ssize_t const n = vsnprintf(S.get(), size, format, args);
+   if (n > -1 && n < size) {
+      out << S.get();
+      return true;
+   } else {
+      if (n > -1)
+	 size = n + 1;
+      else
+	 size *= 2;
+   }
+   return false;
+}
+void ioprintf(ostream &out,const char *format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(out, format, args, size);
+      va_end(args);
+      if (ret == true)
+	 return;
+   }
+}
+void strprintf(string &out,const char *format,...)
+{
+   va_list args;
+   ssize_t size = 400;
+   std::ostringstream outstr;
+   while (true) {
+      bool ret;
+      va_start(args,format);
+      ret = iovprintf(outstr, format, args, size);
+      va_end(args);
+      if (ret == true)
+	 break;
+   }
+   out = outstr.str();
+}
+									/*}}}*/
+// safe_snprintf - Safer snprintf					/*{{{*/
+// ---------------------------------------------------------------------
+/* This is a snprintf that will never (ever) go past 'End' and returns a
+   pointer to the end of the new string. The returned string is always null
+   terminated unless Buffer == end. This is a better alterantive to using
+   consecutive snprintfs. */
+char *safe_snprintf(char *Buffer,char *End,const char *Format,...)
+{
+   va_list args;
+   int Did;
+
+   if (End <= Buffer)
+      return End;
+   va_start(args,Format);
+   Did = vsnprintf(Buffer,End - Buffer,Format,args);
+   va_end(args);
+
+   if (Did < 0 || Buffer + Did > End)
+      return End;
+   return Buffer + Did;
+}
+									/*}}}*/
+// StripEpoch - Remove the version "epoch" from a version string	/*{{{*/
+// ---------------------------------------------------------------------
+string StripEpoch(const string &VerStr)
+{
+   size_t i = VerStr.find(":");
+   if (i == string::npos)
+      return VerStr;
+   return VerStr.substr(i+1);
+}
+									/*}}}*/
+
+// tolower_ascii - tolower() function that ignores the locale		/*{{{*/
+// ---------------------------------------------------------------------
+/* This little function is the most called method we have and tries
+   therefore to do the absolute minimum - and is notable faster than
+   standard tolower/toupper and as a bonus avoids problems with different
+   locales - we only operate on ascii chars anyway. */
+#undef tolower_ascii
+int tolower_ascii(int const c) APT_PURE APT_COLD;
+int tolower_ascii(int const c)
+{
+   return tolower_ascii_inline(c);
+}
+									/*}}}*/
+
+// isspace_ascii - isspace() function that ignores the locale		/*{{{*/
+// ---------------------------------------------------------------------
+/* This little function is one of the most called methods we have and tries
+   therefore to do the absolute minimum - and is notable faster than
+   standard isspace() and as a bonus avoids problems with different
+   locales - we only operate on ascii chars anyway. */
+#undef isspace_ascii
+int isspace_ascii(int const c) APT_PURE APT_COLD;
+int isspace_ascii(int const c)
+{
+   return isspace_ascii_inline(c);
+}
+									/*}}}*/
+
+// CheckDomainList - See if Host is in a , separate list		/*{{{*/
+// ---------------------------------------------------------------------
+/* The domain list is a comma separate list of domains that are suffix
+   matched against the argument */
+bool CheckDomainList(const string &Host,const string &List)
+{
+   string::const_iterator Start = List.begin();
+   for (string::const_iterator Cur = List.begin(); Cur <= List.end(); ++Cur)
+   {
+      if (Cur < List.end() && *Cur != ',')
+	 continue;
+      
+      // Match the end of the string..
+      if ((Host.size() >= (unsigned)(Cur - Start)) &&
+	  Cur - Start != 0 &&
+	  stringcasecmp(Host.end() - (Cur - Start),Host.end(),Start,Cur) == 0)
+	 return true;
+      
+      Start = Cur + 1;
+   }
+   return false;
+}
+									/*}}}*/
+// strv_length - Return the length of a NULL-terminated string array	/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+size_t strv_length(const char **str_array)
+{
+   size_t i;
+   for (i=0; str_array[i] != NULL; i++)
+      /* nothing */
+      ;
+   return i;
+}
+									/*}}}*/
+// DeEscapeString - unescape (\0XX and \xXX) from a string		/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+string DeEscapeString(const string &input)
+{
+   char tmp[3];
+   string::const_iterator it;
+   string output;
+   for (it = input.begin(); it != input.end(); ++it)
+   {
+      // just copy non-escape chars
+      if (*it != '\\')
+      {
+         output += *it;
+         continue;
+      }
+
+      // deal with double escape
+      if (*it == '\\' && 
+          (it + 1 < input.end()) &&  it[1] == '\\')
+      {
+         // copy
+         output += *it;
+         // advance iterator one step further
+         ++it;
+         continue;
+      }
+        
+      // ensure we have a char to read
+      if (it + 1 == input.end())
+         continue;
+
+      // read it
+      ++it;
+      switch (*it)
+      {
+         case '0':
+            if (it + 2 < input.end()) {
+               tmp[0] = it[1];
+               tmp[1] = it[2];
+               tmp[2] = 0;
+               output += (char)strtol(tmp, 0, 8);
+               it += 2;
+            } else {
+	       // FIXME: raise exception here?
+	    }
+            break;
+         case 'x':
+            if (it + 2 < input.end()) {
+               tmp[0] = it[1];
+               tmp[1] = it[2];
+               tmp[2] = 0;
+               output += (char)strtol(tmp, 0, 16);
+               it += 2;
+            } else {
+	       // FIXME: raise exception here?
+	    }
+            break;
+         default:
+            // FIXME: raise exception here?
+            break;
+      }
+   }
+   return output;
+}
+									/*}}}*/
+// URI::CopyFrom - Copy from an object					/*{{{*/
+// ---------------------------------------------------------------------
+/* This parses the URI into all of its components */
+void URI::CopyFrom(const string &U)
+{
+   string::const_iterator I = U.begin();
+
+   // Locate the first colon, this separates the scheme
+   for (; I < U.end() && *I != ':' ; ++I);
+   string::const_iterator FirstColon = I;
+
+   /* Determine if this is a host type URI with a leading double //
+      and then search for the first single / */
+   string::const_iterator SingleSlash = I;
+   if (I + 3 < U.end() && I[1] == '/' && I[2] == '/')
+      SingleSlash += 3;
+   
+   /* Find the / indicating the end of the hostname, ignoring /'s in the
+      square brackets */
+   bool InBracket = false;
+   for (; SingleSlash < U.end() && (*SingleSlash != '/' || InBracket == true); ++SingleSlash)
+   {
+      if (*SingleSlash == '[')
+	 InBracket = true;
+      if (InBracket == true && *SingleSlash == ']')
+	 InBracket = false;
+   }
+   
+   if (SingleSlash > U.end())
+      SingleSlash = U.end();
+
+   // We can now write the access and path specifiers
+   Access.assign(U.begin(),FirstColon);
+   if (SingleSlash != U.end())
+      Path.assign(SingleSlash,U.end());
+   if (Path.empty() == true)
+      Path = "/";
+
+   // Now we attempt to locate a user:pass@host fragment
+   if (FirstColon + 2 <= U.end() && FirstColon[1] == '/' && FirstColon[2] == '/')
+      FirstColon += 3;
+   else
+      FirstColon += 1;
+   if (FirstColon >= U.end())
+      return;
+   
+   if (FirstColon > SingleSlash)
+      FirstColon = SingleSlash;
+   
+   // Find the colon...
+   I = FirstColon + 1;
+   if (I > SingleSlash)
+      I = SingleSlash;
+
+   // Search for the @ separating user:pass from host
+   auto const RevAt = std::find(
+	 std::string::const_reverse_iterator(SingleSlash),
+	 std::string::const_reverse_iterator(I), '@');
+   string::const_iterator const At = RevAt.base() == I ? SingleSlash : std::prev(RevAt.base());
+   // and then look for the colon between user and pass
+   string::const_iterator const SecondColon = std::find(I, At, ':');
+
+   // Now write the host and user/pass
+   if (At == SingleSlash)
+   {
+      if (FirstColon < SingleSlash)
+	 Host.assign(FirstColon,SingleSlash);
+   }
+   else
+   {
+      Host.assign(At+1,SingleSlash);
+      // username and password must be encoded (RFC 3986)
+      User.assign(DeQuoteString(FirstColon,SecondColon));
+      if (SecondColon < At)
+	 Password.assign(DeQuoteString(SecondColon+1,At));
+   }   
+   
+   // Now we parse the RFC 2732 [] hostnames.
+   unsigned long PortEnd = 0;
+   InBracket = false;
+   for (unsigned I = 0; I != Host.length();)
+   {
+      if (Host[I] == '[')
+      {
+	 InBracket = true;
+	 Host.erase(I,1);
+	 continue;
+      }
+      
+      if (InBracket == true && Host[I] == ']')
+      {
+	 InBracket = false;
+	 Host.erase(I,1);
+	 PortEnd = I;
+	 continue;
+      }
+      I++;
+   }
+   
+   // Tsk, weird.
+   if (InBracket == true)
+   {
+      Host.clear();
+      return;
+   }
+   
+   // Now we parse off a port number from the hostname
+   Port = 0;
+   string::size_type Pos = Host.rfind(':');
+   if (Pos == string::npos || Pos < PortEnd)
+      return;
+   
+   Port = atoi(string(Host,Pos+1).c_str());
+   Host.assign(Host,0,Pos);
+}
+									/*}}}*/
+// URI::operator string - Convert the URI to a string			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+URI::operator string()
+{
+   std::stringstream Res;
+
+   if (Access.empty() == false)
+      Res << Access << ':';
+
+   if (Host.empty() == false)
+   {
+      if (Access.empty() == false)
+	 Res << "//";
+
+      if (User.empty() == false)
+      {
+	 // FIXME: Technically userinfo is permitted even less
+	 // characters than these, but this is not conveniently
+	 // expressed with a denylist.
+	 Res << QuoteString(User, ":/?#[]@");
+	 if (Password.empty() == false)
+	    Res << ":" << QuoteString(Password, ":/?#[]@");
+	 Res << "@";
+      }
+
+      // Add RFC 2732 escaping characters
+      if (Access.empty() == false && Host.find_first_of("/:") != string::npos)
+	 Res << '[' << Host << ']';
+      else
+	 Res << Host;
+
+      if (Port != 0)
+	 Res << ':' << std::to_string(Port);
+   }
+
+   if (Path.empty() == false)
+   {
+      if (Path[0] != '/')
+	 Res << "/" << Path;
+      else
+	 Res << Path;
+   }
+
+   return Res.str();
+}
+									/*}}}*/
+// URI::SiteOnly - Return the schema and site for the URI		/*{{{*/
+string URI::SiteOnly(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   U.Path.clear();
+   return U;
+}
+									/*}}}*/
+// URI::ArchiveOnly - Return the schema, site and cleaned path for the URI /*{{{*/
+string URI::ArchiveOnly(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   if (U.Path.empty() == false && U.Path[U.Path.length() - 1] == '/')
+      U.Path.erase(U.Path.length() - 1);
+   return U;
+}
+									/*}}}*/
+// URI::NoUserPassword - Return the schema, site and path for the URI	/*{{{*/
+string URI::NoUserPassword(const string &URI)
+{
+   ::URI U(URI);
+   U.User.clear();
+   U.Password.clear();
+   return U;
+}
+									/*}}}*/
diff --git a/apt-pkg/contrib/strutl.h b/apt-pkg/contrib/strutl.h
new file mode 100644
index 0000000..1fdc8dc
--- /dev/null
+++ b/apt-pkg/contrib/strutl.h
@@ -0,0 +1,252 @@
+// -*- mode: cpp; mode: fold -*-
+// SPDX-License-Identifier: GPL-2.0+
+// Description								/*{{{*/
+/* ######################################################################
+
+   String Util - These are some useful string functions
+   
+   _strstrip is a function to remove whitespace from the front and end
+   of a string.
+   
+   This file had this historic note, but now includes further changes
+   under the GPL-2.0+:
+
+   This source is placed in the Public Domain, do with it what you will
+   It was originally written by Jason Gunthorpe <jgg@gpu.srv.ualberta.ca>   
+   
+   ##################################################################### */
+									/*}}}*/
+#ifndef STRUTL_H
+#define STRUTL_H
+
+#include <cstring>
+#include <iostream>
+#include <limits>
+#include <string>
+#include <vector>
+#include <apt-pkg/string_view.h>
+#include <stddef.h>
+#include <time.h>
+
+#include "macros.h"
+
+
+namespace APT {
+   namespace String {
+      APT_PUBLIC std::string Strip(const std::string &s);
+      APT_PUBLIC bool Endswith(const std::string &s, const std::string &ending);
+      APT_PUBLIC bool Startswith(const std::string &s, const std::string &starting);
+      APT_PUBLIC std::string Join(std::vector<std::string> list, const std::string &sep);
+      // Returns string display length honoring multi-byte characters
+      APT_PUBLIC size_t DisplayLength(StringView str);
+   }
+}
+
+
+APT_PUBLIC bool UTF8ToCodeset(const char *codeset, const std::string &orig, std::string *dest);
+APT_PUBLIC char *_strstrip(char *String);
+APT_PUBLIC char *_strrstrip(char *String); // right strip only
+APT_DEPRECATED_MSG("Use SubstVar to avoid memory headaches") APT_PUBLIC char *_strtabexpand(char *String,size_t Len);
+APT_PUBLIC bool ParseQuoteWord(const char *&String,std::string &Res);
+APT_PUBLIC bool ParseCWord(const char *&String,std::string &Res);
+APT_PUBLIC std::string QuoteString(const std::string &Str,const char *Bad);
+APT_PUBLIC std::string DeQuoteString(const std::string &Str);
+APT_PUBLIC std::string DeQuoteString(std::string::const_iterator const &begin, std::string::const_iterator const &end);
+
+// unescape (\0XX and \xXX) from a string
+APT_PUBLIC std::string DeEscapeString(const std::string &input);
+
+APT_PUBLIC std::string SizeToStr(double Bytes);
+APT_PUBLIC std::string TimeToStr(unsigned long Sec);
+APT_PUBLIC std::string Base64Encode(const std::string &Str);
+APT_PUBLIC std::string OutputInDepth(const unsigned long Depth, const char* Separator="  ");
+APT_PUBLIC std::string URItoFileName(const std::string &URI);
+/** returns a datetime string as needed by HTTP/1.1 and Debian files.
+ *
+ * Note: The date will always be represented in a UTC timezone
+ *
+ * @param Date to be represented as a string
+ * @param NumericTimezone is preferred in general, but HTTP/1.1 requires the use
+ *    of GMT as timezone instead. \b true means that the timezone should be denoted
+ *    as "+0000" while \b false uses "GMT".
+ */
+APT_PUBLIC std::string TimeRFC1123(time_t Date, bool const NumericTimezone);
+/** parses time as needed by HTTP/1.1 and Debian files.
+ *
+ * HTTP/1.1 prefers dates in RFC1123 format (but the other two obsolete date formats
+ * are supported to) and e.g. Release files use the same format in Date & Valid-Until
+ * fields.
+ *
+ * Note: datetime strings need to be in UTC timezones (GMT, UTC, Z, +/-0000) to be
+ * parsed. Other timezones will be rejected as invalid. Previous implementations
+ * accepted other timezones, but treated them as UTC.
+ *
+ * @param str is the datetime string to parse
+ * @param[out] time will be the seconds since epoch of the given datetime if
+ *    parsing is successful, undefined otherwise.
+ * @return \b true if parsing was successful, otherwise \b false.
+ */
+APT_PUBLIC bool RFC1123StrToTime(const std::string &str,time_t &time) APT_MUSTCHECK;
+APT_PUBLIC bool FTPMDTMStrToTime(const char* const str,time_t &time) APT_MUSTCHECK;
+APT_PUBLIC std::string LookupTag(const std::string &Message,const char *Tag,const char *Default = 0);
+APT_PUBLIC int StringToBool(const std::string &Text,int Default = -1);
+APT_PUBLIC bool ReadMessages(int Fd, std::vector<std::string> &List);
+APT_PUBLIC bool StrToNum(const char *Str,unsigned long &Res,unsigned Len,unsigned Base = 0);
+APT_PUBLIC bool StrToNum(const char *Str,unsigned long long &Res,unsigned Len,unsigned Base = 0);
+APT_PUBLIC bool Base256ToNum(const char *Str,unsigned long &Res,unsigned int Len);
+APT_PUBLIC bool Base256ToNum(const char *Str,unsigned long long &Res,unsigned int Len);
+APT_PUBLIC bool Hex2Num(const APT::StringView Str,unsigned char *Num,unsigned int Length);
+// input changing string split
+APT_PUBLIC bool TokSplitString(char Tok,char *Input,char **List,
+		    unsigned long ListMax);
+
+// split a given string by a char
+APT_PUBLIC std::vector<std::string> VectorizeString(std::string const &haystack, char const &split) APT_PURE;
+
+/* \brief Return a vector of strings from string "input" where "sep"
+ * is used as the delimiter string.
+ *
+ * \param input The input string.
+ *
+ * \param sep The separator to use.
+ *
+ * \param maxsplit (optional) The maximum amount of splitting that
+ * should be done .
+ * 
+ * The optional "maxsplit" argument can be used to limit the splitting,
+ * if used the string is only split on maxsplit places and the last
+ * item in the vector contains the remainder string.
+ */
+APT_PUBLIC std::vector<std::string> StringSplit(std::string const &input,
+                                     std::string const &sep, 
+                                     unsigned int maxsplit=std::numeric_limits<unsigned int>::max()) APT_PURE;
+
+
+APT_HIDDEN bool iovprintf(std::ostream &out, const char *format, va_list &args, ssize_t &size);
+APT_PUBLIC void ioprintf(std::ostream &out,const char *format,...) APT_PRINTF(2);
+APT_PUBLIC void strprintf(std::string &out,const char *format,...) APT_PRINTF(2);
+APT_PUBLIC char *safe_snprintf(char *Buffer,char *End,const char *Format,...) APT_PRINTF(3);
+APT_PUBLIC bool CheckDomainList(const std::string &Host, const std::string &List);
+
+/* Do some compat mumbo jumbo */
+#define tolower_ascii  tolower_ascii_inline
+#define isspace_ascii  isspace_ascii_inline
+
+APT_PURE APT_HOT
+static inline int tolower_ascii_unsafe(int const c)
+{
+   return c | 0x20;
+}
+APT_PURE APT_HOT
+static inline int tolower_ascii_inline(int const c)
+{
+   return (c >= 'A' && c <= 'Z') ? c + 32 : c;
+}
+APT_PURE APT_HOT
+static inline int isspace_ascii_inline(int const c)
+{
+   // 9='\t',10='\n',11='\v',12='\f',13='\r',32=' '
+   return (c >= 9 && c <= 13) || c == ' ';
+}
+APT_PURE APT_HOT
+static inline int islower_ascii(int const c)
+{
+   return c >= 'a' && c <= 'z';
+}
+APT_PURE APT_HOT
+static inline int isupper_ascii(int const c)
+{
+   return c >= 'A' && c <= 'Z';
+}
+APT_PURE APT_HOT
+static inline int isalpha_ascii(int const c)
+{
+   return isupper_ascii(c) || islower_ascii(c);
+}
+
+APT_PUBLIC std::string StripEpoch(const std::string &VerStr);
+
+#define APT_MKSTRCMP(name,func) \
+inline APT_PURE int name(const char *A,const char *B) {return func(A,A+strlen(A),B,B+strlen(B));} \
+inline APT_PURE int name(const char *A,const char *AEnd,const char *B) {return func(A,AEnd,B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const char *B) {return func(A.c_str(),A.c_str()+A.length(),B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const std::string& B) {return func(A.c_str(),A.c_str()+A.length(),B.c_str(),B.c_str()+B.length());} \
+inline APT_PURE int name(const std::string& A,const char *B,const char *BEnd) {return func(A.c_str(),A.c_str()+A.length(),B,BEnd);}
+
+#define APT_MKSTRCMP2(name,func) \
+inline APT_PURE int name(const char *A,const char *AEnd,const char *B) {return func(A,AEnd,B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const char *B) {return func(A.begin(),A.end(),B,B+strlen(B));} \
+inline APT_PURE int name(const std::string& A,const std::string& B) {return func(A.begin(),A.end(),B.begin(),B.end());} \
+inline APT_PURE int name(const std::string& A,const char *B,const char *BEnd) {return func(A.begin(),A.end(),B,BEnd);}
+
+APT_PUBLIC int APT_PURE stringcmp(const char *A,const char *AEnd,const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(const char *A,const char *AEnd,const char *B,const char *BEnd);
+
+/* We assume that GCC 3 indicates that libstdc++3 is in use too. In that
+   case the definition of string::const_iterator is not the same as
+   const char * and we need these extra functions */
+#if __GNUC__ >= 3
+APT_PUBLIC int APT_PURE stringcmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+	      const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+	      std::string::const_iterator B,std::string::const_iterator BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+		  const char *B,const char *BEnd);
+APT_PUBLIC int APT_PURE stringcasecmp(std::string::const_iterator A,std::string::const_iterator AEnd,
+                  std::string::const_iterator B,std::string::const_iterator BEnd);
+
+inline APT_PURE int stringcmp(std::string::const_iterator A,std::string::const_iterator Aend,const char *B) {return stringcmp(A,Aend,B,B+strlen(B));}
+inline APT_PURE int stringcasecmp(std::string::const_iterator A,std::string::const_iterator Aend,const char *B) {return stringcasecmp(A,Aend,B,B+strlen(B));}
+#endif
+
+APT_MKSTRCMP2(stringcmp,stringcmp)
+APT_MKSTRCMP2(stringcasecmp,stringcasecmp)
+
+// Return the length of a NULL-terminated string array
+APT_PUBLIC size_t APT_PURE strv_length(const char **str_array);
+
+
+inline const char *DeNull(const char *s) {return (s == 0?"(null)":s);}
+
+class APT_PUBLIC URI
+{
+   void CopyFrom(const std::string &From);
+
+   public:
+
+   std::string Access;
+   std::string User;
+   std::string Password;
+   std::string Host;
+   std::string Path;
+   unsigned int Port;
+   
+   operator std::string();
+   inline void operator =(const std::string &From) {CopyFrom(From);}
+   inline bool empty() {return Access.empty();};
+   static std::string SiteOnly(const std::string &URI);
+   static std::string ArchiveOnly(const std::string &URI);
+   static std::string NoUserPassword(const std::string &URI);
+
+   explicit URI(std::string Path) { CopyFrom(Path); }
+   URI() : Port(0) {}
+};
+
+struct SubstVar
+{
+   const char *Subst;
+   const std::string *Contents;
+};
+APT_PUBLIC std::string SubstVar(std::string Str,const struct SubstVar *Vars);
+APT_PUBLIC std::string SubstVar(const std::string &Str,const std::string &Subst,const std::string &Contents);
+
+struct RxChoiceList
+{
+   void *UserData;
+   const char *Str;
+   bool Hit;
+};
+APT_PUBLIC unsigned long RegexChoice(RxChoiceList *Rxs,const char **ListBegin,
+		      const char **ListEnd);
+
+#endif
diff --git a/apt-pkg/contrib/weakptr.h b/apt-pkg/contrib/weakptr.h
new file mode 100644
index 0000000..8de727d
--- /dev/null
+++ b/apt-pkg/contrib/weakptr.h
@@ -0,0 +1,64 @@
+/* weakptr.h - An object which supports weak pointers.
+ *
+ * Copyright (C) 2010 Julian Andres Klode <jak@debian.org>
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#ifndef WEAK_POINTER_H
+#define WEAK_POINTER_H
+
+#include <set>
+#include <stddef.h>
+
+/**
+ * Class for objects providing support for weak pointers.
+ *
+ * This class allows for the registration of certain pointers as weak,
+ * which will cause them to be set to NULL when the destructor of the
+ * object is called.
+ */
+class WeakPointable {
+private:
+    std::set<WeakPointable**> pointers;
+
+public:
+
+    /**
+     * Add a new weak pointer.
+     */
+    inline void AddWeakPointer(WeakPointable** weakptr) {
+       pointers.insert(weakptr);
+    }
+
+    /**
+     * Remove the weak pointer from the list of weak pointers.
+     */
+    inline void RemoveWeakPointer(WeakPointable **weakptr) {
+       pointers.erase(weakptr);
+    }
+
+    /**
+     * Deconstruct the object, set all weak pointers to NULL.
+     */
+    ~WeakPointable() {
+        std::set<WeakPointable**>::iterator iter = pointers.begin();
+        while (iter != pointers.end())
+            **(iter++) = NULL;
+    }
+};
+
+#endif // WEAK_POINTER_H