store Release files data in the Cache

We used to read the Release file for each Packages file and store the
data in the PackageFile struct even through potentially many Packages
(and Translation-*) files could use the same data. The point of the
exercise isn't the duplicated data through. Having the Release files as
first-class citizens in the Cache allows us to properly track their
state as well as allows us to use the information also for files which
aren't in the cache, but where we know to which Release file they
belong (Sources are an example for this).

This modifies the pkgCache structs, especially the PackagesFile struct
which depending on how libapt users access the data in these structs can
mean huge breakage or no visible change. As a single data point:
aptitude seems to be fine with this. Even if there is breakage it is
trivial to fix in a backportable way while avoiding breakage for
everyone would be a huge pain for us.

Note that not all PackageFile structs have a corresponding ReleaseFile.
In particular the dpkg/status file as well as *.deb files have not. As
these have only a Archive property need, the Component property takes
over this duty and the ReleaseFile remains zero. This is also the reason
why it isn't needed nor particularily recommended to change from
PackagesFile to ReleaseFile blindly. Sticking with the earlier is
usually the better option.

1 files changed, 122 insertions, 2 deletions

diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
index 8e4c2be2d..994b95849 100644
--- a/apt-pkg/deb/debmetaindex.cc
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -1,5 +1,6 @@
 #include <config.h>
 
+#include <apt-pkg/error.h>
 #include <apt-pkg/debmetaindex.h>
 #include <apt-pkg/debindexfile.h>
 #include <apt-pkg/strutl.h>
@@ -10,10 +11,12 @@
 #include <apt-pkg/indexrecords.h>
 #include <apt-pkg/sourcelist.h>
 #include <apt-pkg/hashes.h>
-#include <apt-pkg/macros.h>
 #include <apt-pkg/metaindex.h>
+#include <apt-pkg/pkgcachegen.h>
+#include <apt-pkg/tagfile.h>
+#include <apt-pkg/gpgv.h>
+#include <apt-pkg/macros.h>
 
-#include <string.h>
 #include <map>
 #include <string>
 #include <utility>
@@ -21,6 +24,11 @@
 #include <set>
 #include <algorithm>
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+
 using namespace std;
 
 string debReleaseIndex::MetaIndexInfo(const char *Type) const
@@ -37,6 +45,10 @@ string debReleaseIndex::MetaIndexInfo(const char *Type) const
    Info += Type;
    return Info;
 }
+std::string debReleaseIndex::Describe() const
+{
+   return MetaIndexInfo("Release");
+}
 
 string debReleaseIndex::MetaIndexFile(const char *Type) const
 {
@@ -339,6 +351,114 @@ debReleaseIndex::debSectionEntry::debSectionEntry (string const &Section,
 		bool const &IsSrc): Section(Section), IsSrc(IsSrc)
 {}
 
+static bool ReleaseFileName(debReleaseIndex const * const That, std::string &ReleaseFile)
+{
+   ReleaseFile = That->MetaIndexFile("InRelease");
+   bool releaseExists = false;
+   if (FileExists(ReleaseFile) == true)
+      releaseExists = true;
+   else
+   {
+      ReleaseFile = That->MetaIndexFile("Release");
+      if (FileExists(ReleaseFile))
+	 releaseExists = true;
+   }
+   return releaseExists;
+}
+
+bool debReleaseIndex::Merge(pkgCacheGenerator &Gen,OpProgress * /*Prog*/) const/*{{{*/
+{
+   std::string ReleaseFile;
+   bool const releaseExists = ReleaseFileName(this, ReleaseFile);
+
+   ::URI Tmp(URI);
+   if (Gen.SelectReleaseFile(ReleaseFile, Tmp.Host) == false)
+      return _error->Error("Problem with SelectReleaseFile %s", ReleaseFile.c_str());
+
+   if (releaseExists == false)
+      return true;
+
+   FileFd Rel;
+   // Beware: The 'Release' file might be clearsigned in case the
+   // signature for an 'InRelease' file couldn't be checked
+   if (OpenMaybeClearSignedFile(ReleaseFile, Rel) == false)
+      return false;
+   if (_error->PendingError() == true)
+      return false;
+
+   // Store the IMS information
+   pkgCache::RlsFileIterator File = Gen.GetCurRlsFile();
+   pkgCacheGenerator::Dynamic<pkgCache::RlsFileIterator> DynFile(File);
+   // Rel can't be used as this is potentially a temporary file
+   struct stat Buf;
+   if (stat(ReleaseFile.c_str(), &Buf) != 0)
+      return _error->Errno("fstat", "Unable to stat file %s", ReleaseFile.c_str());
+   File->Size = Buf.st_size;
+   File->mtime = Buf.st_mtime;
+
+   pkgTagFile TagFile(&Rel, Rel.Size());
+   pkgTagSection Section;
+   if (_error->PendingError() == true || TagFile.Step(Section) == false)
+      return false;
+
+   std::string data;
+   #define APT_INRELEASE(TYPE, TAG, STORE) \
+   data = Section.FindS(TAG); \
+   if (data.empty() == false) \
+   { \
+      map_stringitem_t const storage = Gen.StoreString(pkgCacheGenerator::TYPE, data); \
+      STORE = storage; \
+   }
+   APT_INRELEASE(MIXED, "Suite", File->Archive)
+   APT_INRELEASE(VERSIONNUMBER, "Version", File->Version)
+   APT_INRELEASE(MIXED, "Origin", File->Origin)
+   APT_INRELEASE(MIXED, "Codename", File->Codename)
+   APT_INRELEASE(MIXED, "Label", File->Label)
+   #undef APT_INRELEASE
+   Section.FindFlag("NotAutomatic", File->Flags, pkgCache::Flag::NotAutomatic);
+   Section.FindFlag("ButAutomaticUpgrades", File->Flags, pkgCache::Flag::ButAutomaticUpgrades);
+
+   return !_error->PendingError();
+}
+									/*}}}*/
+// ReleaseIndex::FindInCache - Find this index				/*{{{*/
+pkgCache::RlsFileIterator debReleaseIndex::FindInCache(pkgCache &Cache) const
+{
+   std::string ReleaseFile;
+   bool const releaseExists = ReleaseFileName(this, ReleaseFile);
+
+   pkgCache::RlsFileIterator File = Cache.RlsFileBegin();
+   for (; File.end() == false; ++File)
+   {
+       if (File->FileName == 0 || ReleaseFile != File.FileName())
+	 continue;
+
+       // empty means the file does not exist by "design"
+       if (releaseExists == false && File->Size == 0)
+	  return File;
+
+      struct stat St;
+      if (stat(File.FileName(),&St) != 0)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "ReleaseIndex::FindInCache - stat failed on " << File.FileName() << std::endl;
+	 return pkgCache::RlsFileIterator(Cache);
+      }
+      if ((unsigned)St.st_size != File->Size || St.st_mtime != File->mtime)
+      {
+         if (_config->FindB("Debug::pkgCacheGen", false))
+	    std::clog << "ReleaseIndex::FindInCache - size (" << St.st_size << " <> " << File->Size
+			<< ") or mtime (" << St.st_mtime << " <> " << File->mtime
+			<< ") doesn't match for " << File.FileName() << std::endl;
+	 return pkgCache::RlsFileIterator(Cache);
+      }
+      return File;
+   }
+
+   return File;
+}
+									/*}}}*/
+
 class APT_HIDDEN debSLTypeDebian : public pkgSourceList::Type
 {
    protected: