implement POC client-side merging of pdiffs via apt-file

[apt.git] / methods / rred.cc

diff --git a/methods/rred.cc b/methods/rred.cc
index 27d95bdde0a0051ae568a07616921d40748b7711..bea8ed263c100931eda64494f38d125448b3bb35 100644 (file)
--- a/methods/rred.cc
+++ b/methods/rred.cc
@@ -1,262 +1,635 @@
+// Includes                                                                    /*{{{*/
+#include <config.h>
+

 #include <apt-pkg/fileutl.h>
 #include <apt-pkg/fileutl.h>

+#include <apt-pkg/mmap.h>

 #include <apt-pkg/error.h>
 #include <apt-pkg/acquire-method.h>
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/error.h>
 #include <apt-pkg/acquire-method.h>
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/hashes.h>

+#include <apt-pkg/configuration.h>

 
 #include <sys/stat.h>
 
 #include <sys/stat.h>

+#include <sys/uio.h>
+#include <sys/types.h>
+#include <fcntl.h>

 #include <unistd.h>
 #include <utime.h>
 #include <stdio.h>
 #include <errno.h>
 #include <apti18n.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). 
+                                                                               /*}}}*/
+/** \brief RredMethod - ed-style incremential patch method                     {{{
+ *
+ *  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).
+ *  The currently supported ed commands are "<em>c</em>hange", "<em>a</em>dd" and
+ *  "<em>d</em>elete" (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).

  * */
  * */

+class RredMethod : public pkgAcqMethod {
+       bool Debug;
+       // the size of this doesn't really matter (except for performance)
+       const static int BUF_SIZE = 1024;
+       // the supported ed commands
+       enum Mode {MODE_CHANGED='c', MODE_DELETED='d', MODE_ADDED='a'};
+       // return values
+       enum State {ED_OK, ED_ORDERING, ED_PARSER, ED_FAILURE, MMAP_FAILED};

 
 

-const char *Prog;
+       State applyFile(FileFd &ed_cmds, FileFd &in_file, FileFd &out_file,
+                    unsigned long &line, char *buffer, Hashes *hash) const;
+       void ignoreLineInFile(FileFd &fin, char *buffer) const;
+       void copyLinesFromFileToFile(FileFd &fin, FileFd &fout, unsigned int lines,
+                                   Hashes *hash, char *buffer) const;

 
 

-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) {};
+       State patchFile(FileFd &Patch, FileFd &From, FileFd &out_file, Hashes *hash) const;
+       State patchMMap(FileFd &Patch, FileFd &From, FileFd &out_file, Hashes *hash) const;
+
+protected:
+       // the methods main method
+       virtual bool Fetch(FetchItem *Itm);
+
+public:
+       RredMethod() : pkgAcqMethod("1.1",SingleInstance | SendConfig), Debug(false) {};

 };
 };

+                                                                               /*}}}*/
+/** \brief applyFile - in reverse order with a tail recursion                  {{{
+ *
+ *  As it is expected that the commands are in reversed order in the patch file
+ *  we check in the first half if the command is valid, but doesn't execute it
+ *  and move a step deeper. After reaching the end of the file we apply the
+ *  patches in the correct order: last found command first.
+ *
+ *  \param ed_cmds patch file to apply
+ *  \param in_file base file we want to patch
+ *  \param out_file file to write the patched result to
+ *  \param line of command operation
+ *  \param buffer internal used read/write buffer
+ *  \param hash the created file for correctness
+ *  \return the success State of the ed command executor
+ */
+RredMethod::State RredMethod::applyFile(FileFd &ed_cmds, FileFd &in_file, FileFd &out_file,
+                       unsigned long &line, char *buffer, Hashes *hash) const {
+       // get the current command and parse it
+       if (ed_cmds.ReadLine(buffer, BUF_SIZE) == NULL) {
+               if (Debug == true)
+                       std::clog << "rred: encounter end of file - we can start patching now." << std::endl;
+               line = 0;
+               return ED_OK;
+       }

 
 

-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;
-}
+       // parse in the effected linenumbers
+       char* idx;
+       errno=0;
+       unsigned long const startline = strtol(buffer, &idx, 10);
+       if (errno == ERANGE || errno == EINVAL) {
+               _error->Errno("rred", "startline is an invalid number");
+               return ED_PARSER;
+       }
+       if (startline > line) {
+               _error->Error("rred: The start line (%lu) of the next command is higher than the last line (%lu). This is not allowed.", startline, line);
+               return ED_ORDERING;
+       }
+       unsigned long stopline;
+       if (*idx == ',') {
+               idx++;
+               errno=0;
+               stopline = strtol(idx, &idx, 10);
+               if (errno == ERANGE || errno == EINVAL) {
+                       _error->Errno("rred", "stopline is an invalid number");
+                       return ED_PARSER;
+               }
+       }
+       else {
+               stopline = startline;
+       }
+       line = startline;

 
 

-int RredMethod::ed_file(FILE *ed_cmds, FILE *in_file, FILE *out_file, 
-      Hashes *hash) {
+       // which command to execute on this line(s)?
+       switch (*idx) {
+               case MODE_CHANGED:
+                       if (Debug == true)
+                               std::clog << "Change from line " << startline << " to " << stopline << std::endl;
+                       break;
+               case MODE_ADDED:
+                       if (Debug == true)
+                               std::clog << "Insert after line " << startline << std::endl;
+                       break;
+               case MODE_DELETED:
+                       if (Debug == true)
+                               std::clog << "Delete from line " << startline << " to " << stopline << std::endl;
+                       break;
+               default:
+                       _error->Error("rred: Unknown ed command '%c'. Abort.", *idx);
+                       return ED_PARSER;
+       }
+       unsigned char mode = *idx;
+
+       // save the current position
+       unsigned const long long pos = ed_cmds.Tell();
+
+       // if this is add or change then go to the next full stop
+       unsigned int data_length = 0;
+       if (mode == MODE_CHANGED || mode == MODE_ADDED) {
+               do {
+                       ignoreLineInFile(ed_cmds, buffer);
+                       data_length++;
+               }
+               while (strncmp(buffer, ".", 1) != 0);
+               data_length--; // the dot should not be copied
+       }
+
+       // do the recursive call - the last command is the one we need to execute at first
+       const State child = applyFile(ed_cmds, in_file, out_file, line, buffer, hash);
+       if (child != ED_OK) {
+               return child;
+       }
+
+       // change and delete are working on "line" - add is done after "line"
+       if (mode != MODE_ADDED)
+               line++;
+
+       // first wind to the current position and copy over all unchanged lines
+       if (line < startline) {
+               copyLinesFromFileToFile(in_file, out_file, (startline - line), hash, buffer);
+               line = startline;
+       }
+
+       if (mode != MODE_ADDED)
+               line--;
+
+       // include data from ed script
+       if (mode == MODE_CHANGED || mode == MODE_ADDED) {
+               ed_cmds.Seek(pos);
+               copyLinesFromFileToFile(ed_cmds, out_file, data_length, hash, buffer);
+       }
+
+       // ignore the corresponding number of lines from input
+       if (mode == MODE_CHANGED || mode == MODE_DELETED) {
+               while (line < stopline) {
+                       ignoreLineInFile(in_file, buffer);
+                       line++;
+               }
+       }
+       return ED_OK;
+}
+                                                                               /*}}}*/
+void RredMethod::copyLinesFromFileToFile(FileFd &fin, FileFd &fout, unsigned int lines,/*{{{*/
+                                       Hashes *hash, char *buffer) const {
+       while (0 < lines--) {
+               do {
+                       fin.ReadLine(buffer, BUF_SIZE);
+                       unsigned long long const towrite = strlen(buffer);
+                       fout.Write(buffer, towrite);
+                       hash->Add((unsigned char*)buffer, towrite);
+               } while (strlen(buffer) == (BUF_SIZE - 1) &&
+                      buffer[BUF_SIZE - 2] != '\n');
+       }
+}
+                                                                               /*}}}*/
+void RredMethod::ignoreLineInFile(FileFd &fin, char *buffer) const {           /*{{{*/
+       fin.ReadLine(buffer, BUF_SIZE);
+       while (strlen(buffer) == (BUF_SIZE - 1) &&
+              buffer[BUF_SIZE - 2] != '\n') {
+               fin.ReadLine(buffer, BUF_SIZE);
+               buffer[0] = ' ';
+       }
+}
+                                                                               /*}}}*/
+RredMethod::State RredMethod::patchFile(FileFd &Patch, FileFd &From,           /*{{{*/
+                                       FileFd &out_file, Hashes *hash) const {

    char buffer[BUF_SIZE];
    char buffer[BUF_SIZE];

-   int result;
-   int written;
-   
+

    /* we do a tail recursion to read the commands in the right order */
    /* 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);
+   unsigned long line = -1; // assign highest possible value
+   State const result = applyFile(Patch, From, out_file, line, buffer, hash);

    
    /* read the rest from infile */
    
    /* 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);
+   if (result == ED_OK) {
+      while (From.ReadLine(buffer, BUF_SIZE) != NULL) {
+        unsigned long long const towrite = strlen(buffer);
+        out_file.Write(buffer, towrite);
+        hash->Add((unsigned char*)buffer, towrite);

       }
    }
       }
    }

-   else {
-      return ED_FAILURE;
-   }
-   return ED_OK;
+   return result;
+}
+                                                                               /*}}}*/
+/* struct EdCommand                                                            {{{*/
+#ifdef _POSIX_MAPPED_FILES
+struct EdCommand {
+  size_t data_start;
+  size_t data_end;
+  size_t data_lines;
+  size_t first_line;
+  size_t last_line;
+  char type;
+};
+#define IOV_COUNT 1024 /* Don't really want IOV_MAX since it can be arbitrarily large */
+static ssize_t retry_writev(int fd, const struct iovec *iov, int iovcnt) {
+       ssize_t Res;
+       errno = 0;
+       ssize_t i = 0;
+       do {
+               Res = writev(fd, iov + i, iovcnt);
+               if (Res < 0 && errno == EINTR)
+                       continue;
+               if (Res < 0)
+                       return _error->Errno("writev",_("Write error"));
+               iovcnt -= Res;
+               i += Res;
+       } while (Res > 0 && iovcnt > 0);
+       return i;

 }
 }

+#endif
+                                                                               /*}}}*/
+RredMethod::State RredMethod::patchMMap(FileFd &Patch, FileFd &From,           /*{{{*/
+                                       FileFd &out_file, Hashes *hash) const {
+#ifdef _POSIX_MAPPED_FILES
+       MMap ed_cmds(Patch, MMap::ReadOnly);
+       MMap in_file(From, MMap::ReadOnly);
+
+       unsigned long long const ed_size = ed_cmds.Size();
+       unsigned long long const in_size = in_file.Size();
+       if (ed_size == 0 || in_size == 0)
+               return MMAP_FAILED;
+
+       EdCommand* commands = 0;
+       size_t command_count = 0;
+       size_t command_alloc = 0;
+
+       const char* begin = (char*) ed_cmds.Data();
+       const char* end = begin;
+       const char* ed_end = (char*) ed_cmds.Data() + ed_size;
+
+       const char* input = (char*) in_file.Data();
+       const char* input_end = (char*) in_file.Data() + in_size;
+
+       size_t i;
+
+       /* 1. Parse entire script.  It is executed in reverse order, so we cather it
+        *    in the `commands' buffer first
+        */
+
+       for(;;) {
+               EdCommand cmd;
+               cmd.data_start = 0;
+               cmd.data_end = 0;

 
 

+               while(begin != ed_end && *begin == '\n')
+                       ++begin;
+               while(end != ed_end && *end != '\n')
+                       ++end;
+               if(end == ed_end && begin == end)
+                       break;

 
 

-bool RredMethod::Fetch(FetchItem *Itm)
+               /* Determine command range */
+               const char* tmp = begin;
+
+               for(;;) {
+                       /* atoll is safe despite lacking NUL-termination; we know there's an
+                        * alphabetic character at end[-1]
+                        */
+                       if(tmp == end) {
+                               cmd.first_line = atol(begin);
+                               cmd.last_line = cmd.first_line;
+                               break;
+                       }
+                       if(*tmp == ',') {
+                               cmd.first_line = atol(begin);
+                               cmd.last_line = atol(tmp + 1);
+                               break;
+                       }
+                       ++tmp;
+               }
+
+               // which command to execute on this line(s)?
+               switch (end[-1]) {
+                       case MODE_CHANGED:
+                               if (Debug == true)
+                                       std::clog << "Change from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
+                               break;
+                       case MODE_ADDED:
+                               if (Debug == true)
+                                       std::clog << "Insert after line " << cmd.first_line << std::endl;
+                               break;
+                       case MODE_DELETED:
+                               if (Debug == true)
+                                       std::clog << "Delete from line " << cmd.first_line << " to " << cmd.last_line << std::endl;
+                               break;
+                       default:
+                               _error->Error("rred: Unknown ed command '%c'. Abort.", end[-1]);
+                               free(commands);
+                               return ED_PARSER;
+               }
+               cmd.type = end[-1];
+
+               /* Determine the size of the inserted text, so we don't have to scan this
+                * text again later.
+                */
+               begin = end + 1;
+               end = begin;
+               cmd.data_lines = 0;
+
+               if(cmd.type == MODE_ADDED || cmd.type == MODE_CHANGED) {
+                       cmd.data_start = begin - (char*) ed_cmds.Data();
+                       while(end != ed_end) {
+                               if(*end == '\n') {
+                                       if(end[-1] == '.' && end[-2] == '\n')
+                                               break;
+                                       ++cmd.data_lines;
+                               }
+                               ++end;
+                       }
+                       cmd.data_end = end - (char*) ed_cmds.Data() - 1;
+                       begin = end + 1;
+                       end = begin;
+               }
+               if(command_count == command_alloc) {
+                       command_alloc = (command_alloc + 64) * 3 / 2;
+                       EdCommand* newCommands = (EdCommand*) realloc(commands, command_alloc * sizeof(EdCommand));
+                       if (newCommands == NULL) {
+                               free(commands);
+                               return MMAP_FAILED;
+                       }
+                       commands = newCommands;
+               }
+               commands[command_count++] = cmd;
+       }
+
+       struct iovec* iov = new struct iovec[IOV_COUNT];
+       size_t iov_size = 0;
+
+       size_t amount, remaining;
+       size_t line = 1;
+       EdCommand* cmd;
+
+       /* 2. Execute script.  We gather writes in a `struct iov' array, and flush
+        *    using writev to minimize the number of system calls.  Data is read
+        *    directly from the memory mappings of the input file and the script.
+        */
+
+       for(i = command_count; i-- > 0; ) {
+               cmd = &commands[i];
+               if(cmd->type == MODE_ADDED)
+                       amount = cmd->first_line + 1;
+               else
+                       amount = cmd->first_line;
+
+               if(line < amount) {
+                       begin = input;
+                       while(line != amount) {
+                               input = (const char*) memchr(input, '\n', input_end - input);
+                               if(!input)
+                                       break;
+                               ++line;
+                               ++input;
+                       }
+
+                       iov[iov_size].iov_base = (void*) begin;
+                       iov[iov_size].iov_len = input - begin;
+                       hash->Add((const unsigned char*) begin, input - begin);
+
+                       if(++iov_size == IOV_COUNT) {
+                               retry_writev(out_file.Fd(), iov, IOV_COUNT);
+                               iov_size = 0;
+                       }
+               }
+
+               if(cmd->type == MODE_DELETED || cmd->type == MODE_CHANGED) {
+                       remaining = (cmd->last_line - cmd->first_line) + 1;
+                       line += remaining;
+                       while(remaining) {
+                               input = (const char*) memchr(input, '\n', input_end - input);
+                               if(!input)
+                                       break;
+                               --remaining;
+                               ++input;
+                       }
+               }
+
+               if(cmd->type == MODE_CHANGED || cmd->type == MODE_ADDED) {
+                       if(cmd->data_end != cmd->data_start) {
+                               iov[iov_size].iov_base = (void*) ((char*)ed_cmds.Data() + cmd->data_start);
+                               iov[iov_size].iov_len = cmd->data_end - cmd->data_start;
+                               hash->Add((const unsigned char*) ((char*)ed_cmds.Data() + cmd->data_start),
+                               iov[iov_size].iov_len);
+
+                               if(++iov_size == IOV_COUNT) {
+                                       retry_writev(out_file.Fd(), iov, IOV_COUNT);
+                                       iov_size = 0;
+                               }
+                       }
+               }
+       }
+
+       if(input != input_end) {
+               iov[iov_size].iov_base = (void*) input;
+               iov[iov_size].iov_len = input_end - input;
+               hash->Add((const unsigned char*) input, input_end - input);
+               ++iov_size;
+       }
+
+       if(iov_size) {
+               retry_writev(out_file.Fd(), iov, iov_size);
+               iov_size = 0;
+       }
+
+       for(i = 0; i < iov_size; i += IOV_COUNT) {
+               if(iov_size - i < IOV_COUNT)
+                       retry_writev(out_file.Fd(), iov + i, iov_size - i);
+               else
+                       retry_writev(out_file.Fd(), iov + i, IOV_COUNT);
+       }
+
+       delete [] iov;
+       free(commands);
+
+       return ED_OK;
+#else
+       return MMAP_FAILED;
+#endif
+}
+                                                                               /*}}}*/
+bool RredMethod::Fetch(FetchItem *Itm)                                         /*{{{*/

 {
 {

-   Debug = _config->FindB("Debug::pkgAcquire::RRed",false);
+   Debug = _config->FindB("Debug::pkgAcquire::RRed", false);

    URI Get = Itm->Uri;
    URI Get = Itm->Uri;

-   string Path = Get.Host + Get.Path; // To account for relative paths
-   // Path contains the filename to patch
+   std::string Path = Get.Host + Get.Path; // To account for relative paths
+

    FetchResult Res;
    Res.Filename = Itm->DestFile;
    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;
-   
+   if (Itm->Uri.empty() == true) {
+      Path = Itm->DestFile;
+      Itm->DestFile.append(".result");
+   } else
+      URIStart(Res);
+
+   std::string lastPatchName;

    Hashes Hash;
    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;
+
+   // check for a single ed file
+   if (FileExists(Path+".ed") == true)
+   {
+      if (Debug == true)
+        std::clog << "Patching " << Path << " with " << Path
+           << ".ed and putting result into " << Itm->DestFile << std::endl;
+
+      // Open the source and destination files
+      lastPatchName = Path + ".ed";
+      FileFd From(Path,FileFd::ReadOnly);
+      FileFd To(Itm->DestFile,FileFd::WriteAtomic);
+      To.EraseOnFailure();
+      FileFd Patch(lastPatchName, FileFd::ReadOnly, FileFd::Gzip);
+      if (_error->PendingError() == true)
+        return false;
+
+      // now do the actual patching
+      State const result = patchMMap(Patch, From, To, &Hash);
+      if (result == MMAP_FAILED) {
+        // retry with patchFile
+        Patch.Seek(0);
+        From.Seek(0);
+        To.Open(Itm->DestFile,FileFd::WriteAtomic);
+        if (_error->PendingError() == true)
+           return false;
+        if (patchFile(Patch, From, To, &Hash) != ED_OK) {
+           return _error->WarningE("rred", _("Could not patch %s with mmap and with file operation usage - the patch seems to be corrupt."), Path.c_str());
+        } else if (Debug == true) {
+           std::clog << "rred: finished file patching of " << Path  << " after mmap failed." << std::endl;
+        }
+      } else if (result != ED_OK) {
+        return _error->Errno("rred", _("Could not patch %s with mmap (but no mmap specific fail) - the patch seems to be corrupt."), Path.c_str());
+      } else if (Debug == true) {
+        std::clog << "rred: finished mmap patching of " << Path << std::endl;
+      }
+
+      // write out the result
+      From.Close();
+      Patch.Close();
+      To.Close();

    }
    }

+   else
+   {
+      if (Debug == true)
+        std::clog << "Patching " << Path << " with all " << Path << ".ed.*.gz files and "
+           << "putting result into " << Itm->DestFile << std::endl;
+
+      int From = open(Path.c_str(), O_RDONLY);
+      unlink(Itm->DestFile.c_str());
+      int To = open(Itm->DestFile.c_str(), O_WRONLY | O_CREAT | O_EXCL, 0644);
+      SetCloseExec(From, false);
+      SetCloseExec(To, 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)
+      _error->PushToStack();
+      std::vector<std::string> patches = GetListOfFilesInDir(flNotFile(Path), "gz", true, false);
+      _error->RevertToStack();
+
+      std::string externalrred = _config->Find("Dir::Bin::rred", "/usr/bin/diffindex-rred");
+      std::vector<const char *> Args;
+      Args.reserve(22);
+      Args.push_back(externalrred.c_str());
+
+      std::string const baseName = Path + ".ed.";
+      for (std::vector<std::string>::const_iterator p = patches.begin();
+           p != patches.end(); ++p)
+        if (p->compare(0, baseName.length(), baseName) == 0)
+           Args.push_back(p->c_str());
+
+      Args.push_back(NULL);
+
+      pid_t Patcher = ExecFork();
+      if (Patcher == 0) {
+        dup2(From, STDIN_FILENO);
+        dup2(To, STDOUT_FILENO);
+
+        execvp(Args[0], (char **) &Args[0]);
+        std::cerr << "Failed to execute patcher " << Args[0] << "!" << std::endl;
+        _exit(100);
+      }
+      // last is NULL, so the one before is the last patch
+      lastPatchName = Args[Args.size() - 2];
+
+      if (ExecWait(Patcher, "rred") == false)
+        return _error->Errno("rred", "Patching via external rred failed");
+
+      close(From);
+      close(To);
+
+      struct stat Buf;
+      if (stat(Itm->DestFile.c_str(), &Buf) != 0)
+        return _error->Errno("stat",_("Failed to stat"));
+
+      To = open(Path.c_str(), O_RDONLY);
+      Hash.AddFD(To, Buf.st_size);
+      close(To);
+   }
+
+   /* Transfer the modification times from the patch file
+      to be able to see in which state the file should be
+      and use the access time from the "old" file */
+   struct stat BufBase, BufPatch;
+   if (stat(Path.c_str(),&BufBase) != 0 ||
+        stat(lastPatchName.c_str(), &BufPatch) != 0)

       return _error->Errno("stat",_("Failed to stat"));
 
    struct utimbuf TimeBuf;
       return _error->Errno("stat",_("Failed to stat"));
 
    struct utimbuf TimeBuf;

-   TimeBuf.actime = Buf.st_atime;
-   TimeBuf.modtime = Buf.st_mtime;
+   TimeBuf.actime = BufBase.st_atime;
+   TimeBuf.modtime = BufPatch.st_mtime;

    if (utime(Itm->DestFile.c_str(),&TimeBuf) != 0)
       return _error->Errno("utime",_("Failed to set modification time"));
 
    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)
+   if (stat(Itm->DestFile.c_str(),&BufBase) != 0)

       return _error->Errno("stat",_("Failed to stat"));
 
    // return done
       return _error->Errno("stat",_("Failed to stat"));
 
    // return done

-   Res.LastModified = Buf.st_mtime;
-   Res.Size = Buf.st_size;
+   Res.LastModified = BufBase.st_mtime;
+   Res.Size = BufBase.st_size;

    Res.TakeHashes(Hash);
    URIDone(Res);
 
    return true;
 }
    Res.TakeHashes(Hash);
    URIDone(Res);
 
    return true;
 }

-
-int main(int argc, char *argv[])
-{
-   RredMethod Mth;
-
-   Prog = strrchr(argv[0],'/');
-   Prog++;
-   
-   return Mth.Run();
+                                                                               /*}}}*/
+/** \brief Wrapper class for testing rred */                                   /*{{{*/
+class TestRredMethod : public RredMethod {
+public:
+       /** \brief Run rred in debug test mode
+        *
+        *  This method can be used to run the rred method outside
+        *  of the "normal" acquire environment for easier testing.
+        *
+        *  \param base basename of all files involved in this rred test
+        */
+       bool Run(char const *base) {
+               _config->CndSet("Debug::pkgAcquire::RRed", "true");
+               FetchItem *test = new FetchItem;
+               test->DestFile = base;
+               return Fetch(test);
+       }
+};
+                                                                               /*}}}*/
+/** \brief Starter for the rred method (or its test method)                    {{{
+ *
+ *  Used without parameters is the normal behavior for methods for
+ *  the APT acquire system. While this works great for the acquire system
+ *  it is very hard to test the method and therefore the method also
+ *  accepts one parameter which will switch it directly to debug test mode:
+ *  The test mode expects that if "Testfile" is given as parameter
+ *  the file "Testfile" should be ed-style patched with "Testfile.ed"
+ *  and will write the result to "Testfile.result".
+ */
+int main(int argc, char *argv[]) {
+       if (argc <= 1) {
+               RredMethod Mth;
+               return Mth.Run();
+       } else {
+               TestRredMethod Mth;
+               bool result = Mth.Run(argv[1]);
+               _error->DumpErrors();
+               return result;
+       }

 }
 }

+                                                                               /*}}}*/