get pdiff files from the same mirror as the index

In ad9416611ab83f7799f2dcb4bf7f3ef30e9fe6f8 we fall back to asking the
original mirror (e.g. a redirector) if we do not get the expected
result. This works for the indexes, but patches are a different beast
and much simpler. Adding this fallback code here seems like overkill as
they are usually right along their Index file, so actually forward the
relevant settings to the patch items which fixes pdiff support combined
with a redirector and partial mirrors as in such a situation the pdiff
patches would be 404 and the complete index would be downloaded.

(cherry picked from commit 5832913a49d4f7c75527264a935cc0ce00627f1d)

1 files changed, 38 insertions, 14 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index 9c6f85093..b9d9a0af3 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -1018,9 +1018,7 @@ bool pkgAcquire::Item::IsRedirectionLoop(std::string const &NewURI)	/*{{{*/
    return false;
 }
 									/*}}}*/
-
-																		/*}}}*/
-int pkgAcquire::Item::Priority() 				/*{{{*/
+int pkgAcquire::Item::Priority()					/*{{{*/
 {
    // Stage 1: Meta indices and diff indices
    // - those need to be fetched first to have progress reporting working
@@ -2057,7 +2055,7 @@ void pkgAcqDiffIndex::QueueOnIMSHit() const				/*{{{*/
 {
    // list cleanup needs to know that this file as well as the already
    // present index is ours, so we create an empty diff to save it for us
-   new pkgAcqIndexDiffs(Owner, TransactionManager, Target);
+   new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, Target.URI);
 }
 									/*}}}*/
 static bool RemoveFileForBootstrapLinking(bool const Debug, std::string const &For, std::string const &Boot)/*{{{*/
@@ -2433,14 +2431,26 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)	/*{{{*/
       }
    }
 
+   std::string indexURI = Desc.URI;
+   auto const byhashidx = indexURI.find("/by-hash/");
+   if (byhashidx != std::string::npos)
+      indexURI = indexURI.substr(0, byhashidx - strlen(".diff"));
+   else
+   {
+      auto end = indexURI.length() - strlen(".diff/Index");
+      if (CurrentCompressionExtension != "uncompressed")
+	 end -= (1 + CurrentCompressionExtension.length());
+      indexURI = indexURI.substr(0, end);
+   }
+
    if (pdiff_merge == false)
-      new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+      new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, indexURI, available_patches);
    else
    {
       diffs = new std::vector<pkgAcqIndexMergeDiffs*>(available_patches.size());
       for(size_t i = 0; i < available_patches.size(); ++i)
 	 (*diffs)[i] = new pkgAcqIndexMergeDiffs(Owner, TransactionManager,
-               Target,
+               Target, UsedMirror, indexURI,
 	       available_patches[i],
 	       diffs);
    }
@@ -2510,8 +2520,9 @@ pkgAcqDiffIndex::~pkgAcqDiffIndex()
 pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire * const Owner,
                                    pkgAcqMetaClearSig * const TransactionManager,
                                    IndexTarget const &Target,
+				   std::string const &indexUsedMirror, std::string const &indexURI,
 				   vector<DiffInfo> const &diffs)
-   : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL),
+   : pkgAcqBaseIndex(Owner, TransactionManager, Target), indexURI(indexURI),
      available_patches(diffs)
 {
    DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
@@ -2522,6 +2533,12 @@ pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire * const Owner,
    Description = Target.Description;
    Desc.ShortDesc = Target.ShortDesc;
 
+   UsedMirror = indexUsedMirror;
+   if (UsedMirror == "DIRECT")
+      UsedMirror.clear();
+   else if (UsedMirror.empty() == false && Description.find(" ") != string::npos)
+      Description.replace(0, Description.find(" "), UsedMirror);
+
    if(available_patches.empty() == true)
    {
       // we are done (yeah!), check hashes against the final file
@@ -2636,7 +2653,7 @@ bool pkgAcqIndexDiffs::QueueNextDiff()					/*{{{*/
    }
 
    // queue the right diff
-   Desc.URI = Target.URI + ".diff/" + available_patches[0].file + ".gz";
+   Desc.URI = indexURI + ".diff/" + available_patches[0].file + ".gz";
    Desc.Description = Description + " " + available_patches[0].file + string(".pdiff");
    DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI + ".diff/" + available_patches[0].file), Target);
 
@@ -2689,7 +2706,7 @@ void pkgAcqIndexDiffs::Done(string const &Message, HashStringList const &Hashes,
 	 // see if there is more to download
 	 if(available_patches.empty() == false)
 	 {
-	    new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+	    new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, indexURI, available_patches);
 	    Finish();
 	 } else {
 	    DestFile = PatchedFile;
@@ -2718,19 +2735,26 @@ pkgAcqIndexDiffs::~pkgAcqIndexDiffs() {}
 pkgAcqIndexMergeDiffs::pkgAcqIndexMergeDiffs(pkgAcquire * const Owner,
                                              pkgAcqMetaClearSig * const TransactionManager,
                                              IndexTarget const &Target,
+					     std::string const &indexUsedMirror, std::string const &indexURI,
                                              DiffInfo const &patch,
                                              std::vector<pkgAcqIndexMergeDiffs*> const * const allPatches)
-  : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL),
-     patch(patch), allPatches(allPatches), State(StateFetchDiff)
+  : pkgAcqBaseIndex(Owner, TransactionManager, Target), indexURI(indexURI),
+    patch(patch), allPatches(allPatches), State(StateFetchDiff)
 {
    Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
 
-   Desc.Owner = this;
    Description = Target.Description;
+   UsedMirror = indexUsedMirror;
+   if (UsedMirror == "DIRECT")
+      UsedMirror.clear();
+   else if (UsedMirror.empty() == false && Description.find(" ") != string::npos)
+      Description.replace(0, Description.find(" "), UsedMirror);
+
+   Desc.Owner = this;
    Desc.ShortDesc = Target.ShortDesc;
-   Desc.URI = Target.URI + ".diff/" + patch.file + ".gz";
+   Desc.URI = indexURI + ".diff/" + patch.file + ".gz";
    Desc.Description = Description + " " + patch.file + ".pdiff";
-   DestFile = GetPartialFileNameFromURI(Desc.URI);
+   DestFile = GetPartialFileNameFromURI(Target.URI + ".diff/" + patch.file + ".gz");
 
    if(Debug)
       std::clog << "pkgAcqIndexMergeDiffs: " << Desc.URI << std::endl;