* merged pdiff support

Patches applied:

 * michael.vogt@canonical.com--2004/apt--bwlimit--0--base-0
   tag of apt@packages.debian.org/apt--main--0--patch-47

 * michael.vogt@canonical.com--2004/apt--bwlimit--0--patch-1
   * fist attempt for bwlimit

 * michael.vogt@canonical.com--2004/apt--bwlimit--0--patch-2
   * add a nanosleep, making it less cpu intensive

 * michael.vogt@canonical.com--2004/apt--bwlimit--0--patch-3
   * use SingleInstance when DlLimit is activated 

 * michael.vogt@canonical.com--2004/apt--bwlimit--0--patch-4
   * cleanups, no code changes

 * michael.vogt@ubuntu.com--2005/apt--bwlimit--0--base-0
   tag of apt@packages.debian.org/apt--main--0--patch-76

 * michael.vogt@ubuntu.com--2005/apt--bwlimit--0--patch-1
   * merged the apt--main with the 2004 bwlimit tree

 * michael.vogt@ubuntu.com--2005/apt--local-install--0--base-0
   tag of michael.vogt@ubuntu.com--2005/apt--bwlimit--0--patch-1

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--base-0
   tag of michael.vogt@ubuntu.com--2005/apt--local-install--0--base-0

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-1
   * first rewrite of the apt pdiff support patch finished

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-2
   * use "red" now, print meaningfull pdiff names, use IMS for the IndexDiff

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-3
   * merge with matt, search for the right patch next instead of applying them in order

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-4
   * fix a bug QueueNextDiff

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-5
   * another bug in QueueNextDiff fixed

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-6
   * merged with apt--main and apt--fixes

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-7
   * added methods/rred.cc (thanks to robertle)

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-8
   * use the new cool rred method for the patchting

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-9
   * merged with mainline

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-10
   * rred.cc: use the d'tor of FileFd to close the file-fd; acquuire-item.cc: make the QueueNextDiff() code more robust

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-11
   * bugfix/updates in the rred.cc code (big thanks for helping Robert!)

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-12
   * method/rred.cc cleanup (thanks to robertle)

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-13
   * debug support (Debug::pkgAcquire::RRed) for rred method added

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-14
   * split the diff acquire code in a bit that gets the index file and one that gets the patches. that make the code cleaner and the list-cleaner happy

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-15
   * fixed apt-pkg/acquire-item.h (looks like the last commit didn't include it?)

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-16
   * fix a missing StatDone if nothing needs to be fetched

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-17
   * be less verbose and call the Url-Remap: APT::URL-Remap

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-18
   * dont bump the soname, it doesn't break the abi!

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-19
   * merged with michael.vogt@ubuntu.com--2005/apt--mvo--0 to be in sync with debian

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-20
   * don't forget the final md5sum checking!

 * michael.vogt@ubuntu.com--2005/apt--pdiff--0--patch-21
   * removed the URL-Reamp hack (we have pdiff support in the main archive now), removed bw-limit support (NO idea how that got into this archive in the first place)

6 files changed, 740 insertions, 7 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index e0e0611f0..75a7faa2a 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -24,6 +24,8 @@
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/fileutl.h>
 #include <apt-pkg/md5.h>
+#include <apt-pkg/sha1.h>
+#include <apt-pkg/tagfile.h>
 
 #include <apti18n.h>
     
@@ -31,6 +33,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string>
+#include <sstream>
 #include <stdio.h>
 									/*}}}*/
 
@@ -131,14 +134,410 @@ void pkgAcquire::Item::Rename(string From,string To)
 }
 									/*}}}*/
 
+
+// AcqDiffIndex::AcqDiffIndex - Constructor			
+// ---------------------------------------------------------------------
+/* Get the DiffIndex file first and see if there are patches availabe 
+ * If so, create a pkgAcqIndexDiffs fetcher that will get and apply the
+ * patches. If anything goes wrong in that process, it will fall back to
+ * the original packages file
+ */
+pkgAcqDiffIndex::pkgAcqDiffIndex(pkgAcquire *Owner,
+				 string URI,string URIDesc,string ShortDesc,
+				 string ExpectedMD5)
+   : Item(Owner), RealURI(URI), ExpectedMD5(ExpectedMD5), Description(URIDesc)
+{
+   
+   Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
+
+   Desc.Description = URIDesc + "/DiffIndex";
+   Desc.Owner = this;
+   Desc.ShortDesc = ShortDesc;
+   Desc.URI = URI + ".diff/Index";
+
+   DestFile = _config->FindDir("Dir::State::lists") + "partial/";
+   DestFile += URItoFileName(URI) + string(".DiffIndex");
+
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex: " << Desc.URI << std::endl;
+
+   // look for the current package file
+   CurrentPackagesFile = _config->FindDir("Dir::State::lists");
+   CurrentPackagesFile += URItoFileName(RealURI);
+
+   if(!FileExists(CurrentPackagesFile) || 
+      !_config->FindB("Acquire::Diffs",true)) {
+      // we don't have a pkg file or we don't want to queue
+      if(Debug)
+	 std::clog << "No index file or canceld by user" << std::endl;
+      Failed("", NULL);
+      return;
+   }
+
+   if(Debug) {
+      std::clog << "pkgAcqIndexDiffs::pkgAcqIndexDiffs(): " 
+		<< CurrentPackagesFile << std::endl;
+   }
+
+   QueueURI(Desc);
+
+}
+
+// AcqIndex::Custom600Headers - Insert custom request headers		/*{{{*/
+// ---------------------------------------------------------------------
+/* The only header we use is the last-modified header. */
+string pkgAcqDiffIndex::Custom600Headers()
+{
+   string Final = _config->FindDir("Dir::State::lists");
+   Final += URItoFileName(RealURI) + string(".IndexDiff");
+   
+   if(Debug)
+      std::clog << "Custom600Header-IMS: " << Final << std::endl;
+
+   struct stat Buf;
+   if (stat(Final.c_str(),&Buf) != 0)
+      return "\nIndex-File: true";
+   
+   return "\nIndex-File: true\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
+}
+
+
+bool pkgAcqDiffIndex::ParseDiffIndex(string IndexDiffFile)
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs::ParseIndexDiff() " << IndexDiffFile 
+		<< std::endl;
+
+   pkgTagSection Tags;
+   string ServerSha1;
+   vector<DiffInfo> available_patches;
+   
+   FileFd Fd(IndexDiffFile,FileFd::ReadOnly);
+   pkgTagFile TF(&Fd);
+   if (_error->PendingError() == true)
+      return false;
+
+   if(TF.Step(Tags) == true)
+   {
+      string local_sha1;
+      bool found = false;
+      DiffInfo d;
+      string size;
+
+      string tmp = Tags.FindS("SHA1-Current");
+      std::stringstream ss(tmp);
+      ss >> ServerSha1;
+
+      FileFd fd(CurrentPackagesFile, FileFd::ReadOnly);
+      SHA1Summation SHA1;
+      SHA1.AddFD(fd.Fd(), fd.Size());
+      local_sha1 = string(SHA1.Result());
+
+      if(local_sha1 == ServerSha1) {
+	 if(Debug)
+	    std::clog << "Package file is up-to-date" << std::endl;
+	 // set found to true, this will queue a pkgAcqIndexDiffs with
+	 // a empty availabe_patches
+	 found = true;
+      } else {
+	 if(Debug)
+	    std::clog << "SHA1-Current: " << ServerSha1 << std::endl;
+
+	 // check the historie and see what patches we need
+	 string history = Tags.FindS("SHA1-History");     
+	 std::stringstream hist(history);
+	 while(hist >> d.sha1 >> size >> d.file) {
+	    d.size = atoi(size.c_str());
+	    // read until the first match is found
+	    if(d.sha1 == local_sha1) 
+	       found=true;
+	    // from that point on, we probably need all diffs
+	    if(found) {
+	       if(Debug)
+		  std::clog << "Need to get diff: " << d.file << std::endl;
+	       available_patches.push_back(d);
+	    }
+	 }
+      }
+
+      // no information how to get the patches, bail out
+      if(!found) {
+	 if(Debug)
+	    std::clog << "Can't find a patch in the index file" << std::endl;
+	 // Failed will queue a big package file
+	 Failed("", NULL);
+      } else {
+	 // queue the diffs
+	 new pkgAcqIndexDiffs(Owner, RealURI, Description, Desc.ShortDesc,
+			      ExpectedMD5, available_patches);
+	 Complete = false;
+	 Status = StatDone;
+	 Dequeue();
+	 return true;
+      }
+   }
+
+   return false;
+}
+
+void pkgAcqDiffIndex::Failed(string Message,pkgAcquire::MethodConfig *Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex failed: " << Desc.URI << std::endl
+		<< "Falling back to normal index file aquire" << std::endl;
+
+   new pkgAcqIndex(Owner, RealURI, Description, Desc.ShortDesc, 
+		   ExpectedMD5);
+
+   Complete = false;
+   Status = StatDone;
+   Dequeue();
+}
+
+void pkgAcqDiffIndex::Done(string Message,unsigned long Size,string Md5Hash,
+			   pkgAcquire::MethodConfig *Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqDiffIndex::Done(): " << Desc.URI << std::endl;
+
+   Item::Done(Message,Size,Md5Hash,Cnf);
+
+   string FinalFile;
+   FinalFile = _config->FindDir("Dir::State::lists")+URItoFileName(RealURI);
+
+   // sucess in downloading the index
+   // rename the index
+   FinalFile += string(".IndexDiff");
+   if(Debug)
+      std::clog << "Renaming: " << DestFile << " -> " << FinalFile 
+		<< std::endl;
+   Rename(DestFile,FinalFile);
+   chmod(FinalFile.c_str(),0644);
+   DestFile = FinalFile;
+
+   if(!ParseDiffIndex(DestFile))
+      return Failed("", NULL);
+
+   Complete = true;
+   Status = StatDone;
+   Dequeue();
+   return;
+}
+
+
+
+// AcqIndexDiffs::AcqIndexDiffs - Constructor			
+// ---------------------------------------------------------------------
+/* The package diff is added to the queue. one object is constructed
+ * for each diff and the index
+ */
+pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire *Owner,
+				   string URI,string URIDesc,string ShortDesc,
+				   string ExpectedMD5, vector<DiffInfo> diffs)
+   : Item(Owner), RealURI(URI), ExpectedMD5(ExpectedMD5), 
+     available_patches(diffs)
+{
+   
+   DestFile = _config->FindDir("Dir::State::lists") + "partial/";
+   DestFile += URItoFileName(URI);
+
+   Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
+
+   Desc.Description = URIDesc;
+   Desc.Owner = this;
+   Desc.ShortDesc = ShortDesc;
+
+   if(available_patches.size() == 0) {
+      // we are done (yeah!)
+      Finish(true);
+   } else {
+      // get the next diff
+      State = StateFetchDiff;
+      QueueNextDiff();
+   }
+}
+
+
+void pkgAcqIndexDiffs::Failed(string Message,pkgAcquire::MethodConfig *Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs failed: " << Desc.URI << std::endl
+		<< "Falling back to normal index file aquire" << std::endl;
+   new pkgAcqIndex(Owner, RealURI, Description,Desc.ShortDesc, 
+		   ExpectedMD5);
+   Finish();
+}
+
+
+// helper that cleans the item out of the fetcher queue
+void pkgAcqIndexDiffs::Finish(bool allDone)
+{
+   // we restore the original name, this is required, otherwise
+   // the file will be cleaned
+   if(allDone) {
+      DestFile = _config->FindDir("Dir::State::lists");
+      DestFile += URItoFileName(RealURI);
+
+      // do the final md5sum checking
+      MD5Summation sum;
+      FileFd Fd(DestFile, FileFd::ReadOnly);
+      sum.AddFD(Fd.Fd(), Fd.Size());
+      Fd.Close();
+      string MD5 = (string)sum.Result();
+
+      if (!ExpectedMD5.empty() && MD5 != ExpectedMD5)
+      {
+	 Status = StatAuthError;
+	 ErrorText = _("MD5Sum mismatch");
+	 Rename(DestFile,DestFile + ".FAILED");
+	 Dequeue();
+	 return;
+      }
+
+      // this is for the "real" finish
+      Complete = true;
+      Status = StatDone;
+      Dequeue();
+      if(Debug)
+	 std::clog << "\n\nallDone: " << DestFile << "\n" << std::endl;
+      return;
+   }
+
+   if(Debug)
+      std::clog << "Finishing: " << Desc.URI << std::endl;
+   Complete = false;
+   Status = StatDone;
+   Dequeue();
+   return;
+}
+
+
+
+bool pkgAcqIndexDiffs::QueueNextDiff()
+{
+
+   // calc sha1 of the just patched file
+   string FinalFile = _config->FindDir("Dir::State::lists");
+   FinalFile += URItoFileName(RealURI);
+
+   FileFd fd(FinalFile, FileFd::ReadOnly);
+   SHA1Summation SHA1;
+   SHA1.AddFD(fd.Fd(), fd.Size());
+   string local_sha1 = string(SHA1.Result());
+   if(Debug)
+      std::clog << "QueueNextDiff: " 
+		<< FinalFile << " (" << local_sha1 << ")"<<std::endl;
+
+   // remove all patches until the next matching patch is found
+   // this requires the Index file to be ordered
+   for(vector<DiffInfo>::iterator I=available_patches.begin();
+       available_patches.size() > 0 && I != available_patches.end() 
+	  && (*I).sha1 != local_sha1; 
+       I++) {
+      available_patches.erase(I);
+   }
+
+   // error checking and falling back if no patch was found
+   if(available_patches.size() == 0) { 
+      Failed("", NULL);
+      return false;
+   }
+
+   // queue the right diff
+   Desc.URI = string(RealURI) + ".diff/" + available_patches[0].file + ".gz";
+   Desc.Description = available_patches[0].file + string(".pdiff");
+
+   DestFile = _config->FindDir("Dir::State::lists") + "partial/";
+   DestFile += URItoFileName(RealURI + ".diff/" + available_patches[0].file);
+
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs::QueueNextDiff(): " << Desc.URI << std::endl;
+   
+   QueueURI(Desc);
+
+   return true;
+}
+
+
+
+void pkgAcqIndexDiffs::Done(string Message,unsigned long Size,string Md5Hash,
+			    pkgAcquire::MethodConfig *Cnf)
+{
+   if(Debug)
+      std::clog << "pkgAcqIndexDiffs::Done(): " << Desc.URI << std::endl;
+
+   Item::Done(Message,Size,Md5Hash,Cnf);
+
+   string FinalFile;
+   FinalFile = _config->FindDir("Dir::State::lists")+URItoFileName(RealURI);
+
+   // sucess in downloading a diff, enter ApplyDiff state
+   if(State == StateFetchDiff) 
+   {
+
+      if(Debug)
+	 std::clog << "Sending to gzip method: " << FinalFile << std::endl;
+
+      string FileName = LookupTag(Message,"Filename");
+      State = StateUnzipDiff;
+      Desc.URI = "gzip:" + FileName;
+      DestFile += ".decomp";
+      QueueURI(Desc);
+      Mode = "gzip";
+      return;
+   } 
+
+   // sucess in downloading a diff, enter ApplyDiff state
+   if(State == StateUnzipDiff) 
+   {
+
+      // rred excepts the patch as $FinalFile.ed
+      Rename(DestFile,FinalFile+".ed");
+
+      if(Debug)
+	 std::clog << "Sending to rred method: " << FinalFile << std::endl;
+
+      State = StateApplyDiff;
+      Desc.URI = "rred:" + FinalFile;
+      QueueURI(Desc);
+      Mode = "rred";
+      return;
+   } 
+
+
+   // success in download/apply a diff, queue next (if needed)
+   if(State == StateApplyDiff)
+   {
+      // remove the just applied patch
+      available_patches.erase(available_patches.begin());
+
+      // move into place
+      if(Debug) 
+      {
+	 std::clog << "Moving patched file in place: " << std::endl
+		   << DestFile << " -> " << FinalFile << std::endl;
+      }
+      Rename(DestFile,FinalFile);
+
+      // see if there is more to download
+      if(available_patches.size() > 0) {
+	 new pkgAcqIndexDiffs(Owner, RealURI, Description, Desc.ShortDesc,
+			      ExpectedMD5, available_patches);
+	 return Finish();
+      } else 
+	 return Finish(true);
+   }
+}
+
+
 // AcqIndex::AcqIndex - Constructor					/*{{{*/
 // ---------------------------------------------------------------------
 /* The package file is added to the queue and a second class is 
    instantiated to fetch the revision file */   
 pkgAcqIndex::pkgAcqIndex(pkgAcquire *Owner,
 			 string URI,string URIDesc,string ShortDesc,
-			 string ExpectedMD5, string comprExt) :
-   Item(Owner), RealURI(URI), ExpectedMD5(ExpectedMD5)
+			 string ExpectedMD5, string comprExt)
+   : Item(Owner), RealURI(URI), ExpectedMD5(ExpectedMD5)
 {
    Decompression = false;
    Erase = false;
@@ -636,8 +1035,8 @@ void pkgAcqMetaIndex::QueueIndexes(bool verify)
       }
       
       // Queue Packages file
-      new pkgAcqIndex(Owner, (*Target)->URI, (*Target)->Description,
-                      (*Target)->ShortDesc, ExpectedIndexMD5);
+      new pkgAcqDiffIndex(Owner, (*Target)->URI, (*Target)->Description,
+			  (*Target)->ShortDesc, ExpectedIndexMD5);
    }
 }
 
diff --git a/apt-pkg/acquire-item.h b/apt-pkg/acquire-item.h
index ae2fba4d5..34fcc2a76 100644
--- a/apt-pkg/acquire-item.h
+++ b/apt-pkg/acquire-item.h
@@ -82,6 +82,70 @@ class pkgAcquire::Item
    virtual ~Item();
 };
 
+// item for index diffs
+
+struct DiffInfo {
+   string file;
+   string sha1;
+   unsigned long size;
+};
+
+class pkgAcqDiffIndex : public pkgAcquire::Item
+{
+ protected:
+   bool Debug;
+   pkgAcquire::ItemDesc Desc;
+   string RealURI;
+   string ExpectedMD5;
+   string CurrentPackagesFile;
+   string Description;
+
+ public:
+   // Specialized action members
+   virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+   virtual void Done(string Message,unsigned long Size,string Md5Hash,
+		     pkgAcquire::MethodConfig *Cnf);
+   virtual string DescURI() {return RealURI + "Index";};
+   virtual string Custom600Headers();
+
+   // helpers
+   bool ParseDiffIndex(string IndexDiffFile);
+   
+   pkgAcqDiffIndex(pkgAcquire *Owner,string URI,string URIDesc,
+		   string ShortDesct, string ExpectedMD5);
+};
+
+class pkgAcqIndexDiffs : public pkgAcquire::Item
+{
+   protected:
+   bool Debug;
+   pkgAcquire::ItemDesc Desc;
+   string RealURI;
+   string ExpectedMD5;
+
+   // this is the SHA-1 sum we expect after the patching
+   string Description;
+   vector<DiffInfo> available_patches;
+   enum {StateFetchIndex,StateFetchDiff,StateUnzipDiff,StateApplyDiff} State;
+
+   public:
+   
+   // Specialized action members
+   virtual void Failed(string Message,pkgAcquire::MethodConfig *Cnf);
+   virtual void Done(string Message,unsigned long Size,string Md5Hash,
+		     pkgAcquire::MethodConfig *Cnf);
+   virtual string DescURI() {return RealURI + "Index";};
+
+   // various helpers
+   bool QueueNextDiff();
+   bool ApplyDiff(string PatchFile);
+   void Finish(bool allDone=false);
+
+   pkgAcqIndexDiffs(pkgAcquire *Owner,string URI,string URIDesc,
+		    string ShortDesct, string ExpectedMD5,
+		    vector<DiffInfo> diffs=vector<DiffInfo>());
+};
+
 // Item class for index files
 class pkgAcqIndex : public pkgAcquire::Item
 {
diff --git a/apt-pkg/init.h b/apt-pkg/init.h
index e21351797..8255b406a 100644
--- a/apt-pkg/init.h
+++ b/apt-pkg/init.h
@@ -18,7 +18,7 @@
 
 // See the makefile
 #define APT_PKG_MAJOR 3
-#define APT_PKG_MINOR 10
+#define APT_PKG_MINOR 11
 #define APT_PKG_RELEASE 0
     
 extern const char *pkgVersion;
diff --git a/methods/http.cc b/methods/http.cc
index ba86aa6b6..e2337a9ba 100644
--- a/methods/http.cc
+++ b/methods/http.cc
@@ -58,6 +58,7 @@ unsigned long PipelineDepth = 10;
 unsigned long TimeOut = 120;
 bool Debug = false;
 
+
 // CircleBuf::CircleBuf - Circular input buffer				/*{{{*/
 // ---------------------------------------------------------------------
 /* */
@@ -95,7 +96,7 @@ bool CircleBuf::Read(int Fd)
       // Woops, buffer is full
       if (InP - OutP == Size)
 	 return true;
-      
+
       // Write the buffer segment
       int Res;
       Res = read(Fd,Buf + (InP%Size),LeftRead());
diff --git a/methods/makefile b/methods/makefile
index 06fd2a6fc..d0b5a28c0 100644
--- a/methods/makefile
+++ b/methods/makefile
@@ -7,7 +7,7 @@ include ../buildlib/defaults.mak
 BIN := $(BIN)/methods
 
 # FIXME..
-LIB_APT_PKG_MAJOR = 3.10
+LIB_APT_PKG_MAJOR = 3.11
 APT_DOMAIN := libapt-pkg$(LIB_APT_PKG_MAJOR)
 
 # The file method
@@ -59,6 +59,13 @@ LIB_MAKES = apt-pkg/makefile
 SOURCE = ftp.cc rfc2553emu.cc connect.cc
 include $(PROGRAM_H)
 
+# The rred method
+PROGRAM=rred
+SLIBS = -lapt-pkg $(SOCKETLIBS)
+LIB_MAKES = apt-pkg/makefile
+SOURCE = rred.cc
+include $(PROGRAM_H)
+
 # The rsh method
 PROGRAM=rsh
 SLIBS = -lapt-pkg
diff --git a/methods/rred.cc b/methods/rred.cc
new file mode 100644
index 000000000..6fa57f3a6
--- /dev/null
+++ b/methods/rred.cc
@@ -0,0 +1,262 @@
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/acquire-method.h>
+#include <apt-pkg/strutl.h>
+#include <apt-pkg/hashes.h>
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <utime.h>
+#include <stdio.h>
+#include <errno.h>
+#include <apti18n.h>
+
+/* this method implements a patch functionality similar to "patch --ed" that is
+ * used by the "tiffany" incremental packages download stuff. it differs from 
+ * "ed" insofar that it is way more restricted (and therefore secure). in the
+ * moment only the "c", "a" and "d" commands of ed are implemented (diff 
+ * doesn't output any other). additionally the records must be reverse sorted 
+ * by line number and may not overlap (diff *seems* to produce this kind of 
+ * output). 
+ * */
+
+const char *Prog;
+
+class RredMethod : public pkgAcqMethod
+{
+   bool Debug;
+   // the size of this doesn't really matter (except for performance)    
+   const static int BUF_SIZE = 1024;
+   // the ed commands
+   enum Mode {MODE_CHANGED, MODE_DELETED, MODE_ADDED};
+   // return values
+   enum State {ED_OK, ED_ORDERING, ED_PARSER, ED_FAILURE};
+   // this applies a single hunk, it uses a tail recursion to 
+   // reverse the hunks in the file
+   int ed_rec(FILE *ed_cmds, FILE *in_file, FILE *out_file, int line, 
+      char *buffer, unsigned int bufsize, Hashes *hash);
+   // apply a patch file
+   int ed_file(FILE *ed_cmds, FILE *in_file, FILE *out_file, Hashes *hash);
+   // the methods main method
+   virtual bool Fetch(FetchItem *Itm);
+   
+   public:
+   
+   RredMethod() : pkgAcqMethod("1.1",SingleInstance | SendConfig) {};
+};
+
+int RredMethod::ed_rec(FILE *ed_cmds, FILE *in_file, FILE *out_file, int line, 
+      char *buffer, unsigned int bufsize, Hashes *hash) {
+   int pos;
+   int startline;
+   int stopline;
+   int mode;
+   int written;
+   char *idx;
+
+   /* get the current command and parse it*/
+   if (fgets(buffer, bufsize, ed_cmds) == NULL) {
+      return line;
+   }
+   startline = strtol(buffer, &idx, 10);
+   if (startline < line) {
+      return ED_ORDERING;
+   }
+   if (*idx == ',') {
+      idx++;
+      stopline = strtol(idx, &idx, 10);
+   }
+   else {
+      stopline = startline;
+   }
+   if (*idx == 'c') {
+      mode = MODE_CHANGED;
+	   if (Debug == true) {
+		   std::clog << "changing from line " << startline 
+			     << " to " << stopline << std::endl;
+	   }
+   }
+   else if (*idx == 'a') {
+      mode = MODE_ADDED;
+	   if (Debug == true) {
+		   std::clog << "adding after line " << startline << std::endl;
+	   }
+   }
+   else if (*idx == 'd') {
+      mode = MODE_DELETED;
+	   if (Debug == true) {
+		   std::clog << "deleting from line " << startline 
+			     <<  " to " << stopline << std::endl;
+	   }
+   }
+   else {
+      return ED_PARSER;
+   }
+   /* get the current position */
+   pos = ftell(ed_cmds);
+   /* if this is add or change then go to the next full stop */
+   if ((mode == MODE_CHANGED) || (mode == MODE_ADDED)) {
+      do {
+         fgets(buffer, bufsize, ed_cmds);
+         while ((strlen(buffer) == (bufsize - 1)) 
+               && (buffer[bufsize - 2] != '\n')) {
+            fgets(buffer, bufsize, ed_cmds);
+            buffer[0] = ' ';
+         }
+      } while (strncmp(buffer, ".", 1) != 0);
+   }
+   /* do the recursive call */
+   line = ed_rec(ed_cmds, in_file, out_file, line, buffer, bufsize, 
+         hash);
+   /* pass on errors */
+   if (line < 0) {
+      return line;
+   }
+   /* apply our hunk */
+   fseek(ed_cmds, pos, SEEK_SET); 
+   /* first wind to the current position */
+   if (mode != MODE_ADDED) {
+      startline -= 1;
+   }
+   while (line < startline) {
+      fgets(buffer, bufsize, in_file);
+      written = fwrite(buffer, 1, strlen(buffer), out_file);
+      hash->Add((unsigned char*)buffer, written);
+      while ((strlen(buffer) == (bufsize - 1)) 
+            && (buffer[bufsize - 2] != '\n')) {
+         fgets(buffer, bufsize, in_file);
+         written = fwrite(buffer, 1, strlen(buffer), out_file);
+         hash->Add((unsigned char*)buffer, written);
+      }
+      line++;
+   }
+   /* include from ed script */
+   if ((mode == MODE_ADDED) || (mode == MODE_CHANGED)) {
+      do {
+         fgets(buffer, bufsize, ed_cmds);
+         if (strncmp(buffer, ".", 1) != 0) {
+            written = fwrite(buffer, 1, strlen(buffer), out_file);
+            hash->Add((unsigned char*)buffer, written);
+            while ((strlen(buffer) == (bufsize - 1)) 
+                  && (buffer[bufsize - 2] != '\n')) {
+               fgets(buffer, bufsize, ed_cmds);
+               written = fwrite(buffer, 1, strlen(buffer), out_file);
+               hash->Add((unsigned char*)buffer, written);
+            }
+         }
+         else {
+            break;
+         }
+      } while (1);
+   }
+   /* ignore the corresponding number of lines from input */
+   if ((mode == MODE_DELETED) || (mode == MODE_CHANGED)) {
+      while (line < stopline) {
+         fgets(buffer, bufsize, in_file);
+         while ((strlen(buffer) == (bufsize - 1)) 
+               && (buffer[bufsize - 2] != '\n')) {
+            fgets(buffer, bufsize, in_file);
+         }
+         line++;
+      }
+   }
+   return line;
+}
+
+int RredMethod::ed_file(FILE *ed_cmds, FILE *in_file, FILE *out_file, 
+      Hashes *hash) {
+   char buffer[BUF_SIZE];
+   int result;
+   int written;
+   
+   /* we do a tail recursion to read the commands in the right order */
+   result = ed_rec(ed_cmds, in_file, out_file, 0, buffer, BUF_SIZE, 
+         hash);
+   
+   /* read the rest from infile */
+   if (result > 0) {
+      while (fgets(buffer, BUF_SIZE, in_file) != NULL) {
+         written = fwrite(buffer, 1, strlen(buffer), out_file);
+         hash->Add((unsigned char*)buffer, written);
+      }
+   }
+   else {
+      return ED_FAILURE;
+   }
+   return ED_OK;
+}
+
+
+bool RredMethod::Fetch(FetchItem *Itm)
+{
+   Debug = _config->FindB("Debug::pkgAcquire::RRed",false);
+   URI Get = Itm->Uri;
+   string Path = Get.Host + Get.Path; // To account for relative paths
+   // Path contains the filename to patch
+   FetchResult Res;
+   Res.Filename = Itm->DestFile;
+   URIStart(Res);
+   // Res.Filename the destination filename
+
+   if (Debug == true) 
+      std::clog << "Patching " << Path << " with " << Path 
+         << ".ed and putting result into " << Itm->DestFile << std::endl;
+   // Open the source and destination files (the d'tor of FileFd will do 
+   // the cleanup/closing of the fds)
+   FileFd From(Path,FileFd::ReadOnly);
+   FileFd Patch(Path+".ed",FileFd::ReadOnly);
+   FileFd To(Itm->DestFile,FileFd::WriteEmpty);   
+   To.EraseOnFailure();
+   if (_error->PendingError() == true)
+      return false;
+   
+   Hashes Hash;
+   FILE* fFrom = fdopen(From.Fd(), "r");
+   FILE* fPatch = fdopen(Patch.Fd(), "r");
+   FILE* fTo = fdopen(To.Fd(), "w");
+   // now do the actual patching
+   if (ed_file(fPatch, fFrom, fTo, &Hash) != ED_OK) {
+     _error->Errno("rred", _("Could not patch file"));  
+      return false;
+   }
+
+   // write out the result
+   fflush(fFrom);
+   fflush(fPatch);
+   fflush(fTo);
+   From.Close();
+   Patch.Close();
+   To.Close();
+
+   // Transfer the modification times
+   struct stat Buf;
+   if (stat(Path.c_str(),&Buf) != 0)
+      return _error->Errno("stat",_("Failed to stat"));
+
+   struct utimbuf TimeBuf;
+   TimeBuf.actime = Buf.st_atime;
+   TimeBuf.modtime = Buf.st_mtime;
+   if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
+      return _error->Errno("utime",_("Failed to set modification time"));
+
+   if (stat(Itm->DestFile.c_str(),&Buf) != 0)
+      return _error->Errno("stat",_("Failed to stat"));
+
+   // return done
+   Res.LastModified = Buf.st_mtime;
+   Res.Size = Buf.st_size;
+   Res.TakeHashes(Hash);
+   URIDone(Res);
+
+   return true;
+}
+
+int main(int argc, char *argv[])
+{
+   RredMethod Mth;
+
+   Prog = strrchr(argv[0],'/');
+   Prog++;
+   
+   return Mth.Run();
+}