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, 56 insertions, 21 deletions

diff --git a/apt-pkg/pkgcache.cc b/apt-pkg/pkgcache.cc
index 864ae0f60..9fe382108 100644
--- a/apt-pkg/pkgcache.cc
+++ b/apt-pkg/pkgcache.cc
@@ -61,6 +61,7 @@ pkgCache::Header::Header()
    HeaderSz = sizeof(pkgCache::Header);
    GroupSz = sizeof(pkgCache::Group);
    PackageSz = sizeof(pkgCache::Package);
+   ReleaseFileSz = sizeof(pkgCache::ReleaseFile);
    PackageFileSz = sizeof(pkgCache::PackageFile);
    VersionSz = sizeof(pkgCache::Version);
    DescriptionSz = sizeof(pkgCache::Description);
@@ -74,6 +75,7 @@ pkgCache::Header::Header()
    VersionCount = 0;
    DescriptionCount = 0;
    DependsCount = 0;
+   ReleaseFileCount = 0;
    PackageFileCount = 0;
    VerFileCount = 0;
    DescFileCount = 0;
@@ -82,6 +84,7 @@ pkgCache::Header::Header()
    MaxDescFileSize = 0;
    
    FileList = 0;
+   RlsFileList = 0;
 #if APT_PKG_ABI < 413
    APT_IGNORE_DEPRECATED(StringList = 0;)
 #endif
@@ -102,6 +105,7 @@ bool pkgCache::Header::CheckSizes(Header &Against) const
    if (HeaderSz == Against.HeaderSz &&
        GroupSz == Against.GroupSz &&
        PackageSz == Against.PackageSz &&
+       ReleaseFileSz == Against.ReleaseFileSz &&
        PackageFileSz == Against.PackageFileSz &&
        VersionSz == Against.VersionSz &&
        DescriptionSz == Against.DescriptionSz &&
@@ -140,6 +144,7 @@ bool pkgCache::ReMap(bool const &Errorchecks)
    PkgP = (Package *)Map.Data();
    VerFileP = (VerFile *)Map.Data();
    DescFileP = (DescFile *)Map.Data();
+   RlsFileP = (ReleaseFile *)Map.Data();
    PkgFileP = (PackageFile *)Map.Data();
    VerP = (Version *)Map.Data();
    DescP = (Description *)Map.Data();
@@ -814,7 +819,7 @@ APT_PURE bool pkgCache::VerIterator::Downloadable() const
 {
    VerFileIterator Files = FileList();
    for (; Files.end() == false; ++Files)
-      if ((Files.File()->Flags & pkgCache::Flag::NotSource) != pkgCache::Flag::NotSource)
+      if (Files.File().Flagged(pkgCache::Flag::NotSource) == false)
 	 return true;
    return false;
 }
@@ -828,7 +833,7 @@ APT_PURE bool pkgCache::VerIterator::Automatic() const
    VerFileIterator Files = FileList();
    for (; Files.end() == false; ++Files)
       // Do not check ButAutomaticUpgrades here as it is kind of automatic…
-      if ((Files.File()->Flags & pkgCache::Flag::NotAutomatic) != pkgCache::Flag::NotAutomatic)
+      if (Files.File().Flagged(pkgCache::Flag::NotAutomatic) == false)
 	 return true;
    return false;
 }
@@ -861,27 +866,27 @@ string pkgCache::VerIterator::RelStr() const
    for (pkgCache::VerFileIterator I = this->FileList(); I.end() == false; ++I)
    {
       // Do not print 'not source' entries'
-      pkgCache::PkgFileIterator File = I.File();
-      if ((File->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
+      pkgCache::PkgFileIterator const File = I.File();
+      if (File.Flagged(pkgCache::Flag::NotSource))
 	 continue;
 
       // See if we have already printed this out..
       bool Seen = false;
       for (pkgCache::VerFileIterator J = this->FileList(); I != J; ++J)
       {
-	 pkgCache::PkgFileIterator File2 = J.File();
-	 if (File2->Label == 0 || File->Label == 0)
+	 pkgCache::PkgFileIterator const File2 = J.File();
+	 if (File2.Label() == 0 || File.Label() == 0)
 	    continue;
 
 	 if (strcmp(File.Label(),File2.Label()) != 0)
 	    continue;
 	 
-	 if (File2->Version == File->Version)
+	 if (File2.Version() == File.Version())
 	 {
 	    Seen = true;
 	    break;
 	 }
-	 if (File2->Version == 0 || File->Version == 0)
+	 if (File2.Version() == 0 || File.Version() == 0)
 	    break;
 	 if (strcmp(File.Version(),File2.Version()) == 0)
 	    Seen = true;
@@ -895,12 +900,12 @@ string pkgCache::VerIterator::RelStr() const
       else
 	 First = false;
       
-      if (File->Label != 0)
+      if (File.Label() != 0)
 	 Res = Res + File.Label() + ':';
 
-      if (File->Archive != 0)
+      if (File.Archive() != 0)
       {
-	 if (File->Version == 0)
+	 if (File.Version() == 0)
 	    Res += File.Archive();
 	 else
 	    Res = Res + File.Version() + '/' +  File.Archive();
@@ -908,7 +913,7 @@ string pkgCache::VerIterator::RelStr() const
       else
       {
 	 // No release file, print the host name that this came from
-	 if (File->Site == 0 || File.Site()[0] == 0)
+	 if (File.Site() == 0 || File.Site()[0] == 0)
 	    Res += "localhost";
 	 else
 	    Res += File.Site();
@@ -931,12 +936,12 @@ const char * pkgCache::VerIterator::MultiArchType() const
    return "none";
 }
 									/*}}}*/
-// PkgFileIterator::IsOk - Checks if the cache is in sync with the file	/*{{{*/
+// RlsFileIterator::IsOk - Checks if the cache is in sync with the file	/*{{{*/
 // ---------------------------------------------------------------------
 /* This stats the file and compares its stats with the ones that were
-   stored during generation. Date checks should probably also be 
+   stored during generation. Date checks should probably also be
    included here. */
-bool pkgCache::PkgFileIterator::IsOk()
+bool pkgCache::RlsFileIterator::IsOk()
 {
    struct stat Buf;
    if (stat(FileName(),&Buf) != 0)
@@ -948,10 +953,8 @@ bool pkgCache::PkgFileIterator::IsOk()
    return true;
 }
 									/*}}}*/
-// PkgFileIterator::RelStr - Return the release string			/*{{{*/
-// ---------------------------------------------------------------------
-/* */
-string pkgCache::PkgFileIterator::RelStr()
+// RlsFileIterator::RelStr - Return the release string			/*{{{*/
+string pkgCache::RlsFileIterator::RelStr()
 {
    string Res;
    if (Version() != 0)
@@ -964,8 +967,40 @@ string pkgCache::PkgFileIterator::RelStr()
       Res = Res + (Res.empty() == true?"n=":",n=")  + Codename();
    if (Label() != 0)
       Res = Res + (Res.empty() == true?"l=":",l=")  + Label();
-   if (Component() != 0)
-      Res = Res + (Res.empty() == true?"c=":",c=")  + Component();
+   return Res;
+}
+									/*}}}*/
+// PkgFileIterator::IsOk - Checks if the cache is in sync with the file	/*{{{*/
+// ---------------------------------------------------------------------
+/* This stats the file and compares its stats with the ones that were
+   stored during generation. Date checks should probably also be
+   included here. */
+bool pkgCache::PkgFileIterator::IsOk()
+{
+   struct stat Buf;
+   if (stat(FileName(),&Buf) != 0)
+      return false;
+
+   if (Buf.st_size != (signed)S->Size || Buf.st_mtime != S->mtime)
+      return false;
+
+   return true;
+}
+									/*}}}*/
+string pkgCache::PkgFileIterator::RelStr()				/*{{{*/
+{
+   std::string Res;
+   if (ReleaseFile() == 0)
+   {
+      if (Component() != 0)
+	 Res = Res + (Res.empty() == true?"a=":",a=")  + Component();
+   }
+   else
+   {
+      Res = ReleaseFile().RelStr();
+      if (Component() != 0)
+	 Res = Res + (Res.empty() == true?"c=":",c=")  + Component();
+   }
    if (Architecture() != 0)
       Res = Res + (Res.empty() == true?"b=":",b=")  + Architecture();
    return Res;