drop stored StringItems in favor of in-memory mappings

Strings like Section names or architectures are needed vary often.
Instead of writing them each time we need them, we deploy sharing for
these special strings. Until now, this was done with a linked list of
strings in which we would search, which was stored in the cache.
It turns out we can do this just as well in memory as well with a bunch
of std::map's.

In memory means here that it isn't available anymore if we have a partly
invalid cache, but that isn't much of a problem in practice as the
status file is compared to the other files we parse very small and includes
mostly duplicates, so the space we would gain by storing is more or less
equal to the size of the stored linked list…

3 files changed, 20 insertions, 28 deletions

diff --git a/apt-pkg/deb/debindexfile.cc b/apt-pkg/deb/debindexfile.cc
index feda8d0d8..c35a89ade 100644
--- a/apt-pkg/deb/debindexfile.cc
+++ b/apt-pkg/deb/debindexfile.cc
@@ -619,7 +619,7 @@ bool debStatusIndex::Merge(pkgCacheGenerator &Gen,OpProgress *Prog) const
    pkgCache::PkgFileIterator CFile = Gen.GetCurFile();
    CFile->Size = Pkg.FileSize();
    CFile->mtime = Pkg.ModificationTime();
-   map_stringitem_t const storage = Gen.WriteUniqString("now");
+   map_stringitem_t const storage = Gen.StoreString(pkgCacheGenerator::MIXED, "now");
    CFile->Archive = storage;
    
    if (Gen.MergeList(Parser) == false)
diff --git a/apt-pkg/deb/deblistparser.cc b/apt-pkg/deb/deblistparser.cc
index 3e0d3a791..9919d2036 100644
--- a/apt-pkg/deb/deblistparser.cc
+++ b/apt-pkg/deb/deblistparser.cc
@@ -58,18 +58,6 @@ debListParser::debListParser(FileFd *File, string const &Arch) : Tags(File),
    MultiArchEnabled = Architectures.size() > 1;
 }
 									/*}}}*/
-// ListParser::UniqFindTagWrite - Find the tag and write a unq string	/*{{{*/
-// ---------------------------------------------------------------------
-/* */
-map_stringitem_t debListParser::UniqFindTagWrite(const char *Tag)
-{
-   const char *Start;
-   const char *Stop;
-   if (Section.Find(Tag,Start,Stop) == false)
-      return 0;
-   return WriteUniqString(Start,Stop - Start);
-}
-									/*}}}*/
 // ListParser::Package - Return the package name			/*{{{*/
 // ---------------------------------------------------------------------
 /* This is to return the name of the package this section describes */
@@ -144,9 +132,16 @@ unsigned char debListParser::ParseMultiArch(bool const showErrors)	/*{{{*/
 /* */
 bool debListParser::NewVersion(pkgCache::VerIterator &Ver)
 {
+   const char *Start;
+   const char *Stop;
+
    // Parse the section
-   unsigned long const idxSection = UniqFindTagWrite("Section");
-   Ver->Section = idxSection;
+   if (Section.Find("Section",Start,Stop) == true)
+   {
+      map_stringitem_t const idx = StoreString(pkgCacheGenerator::SECTION, Start, Stop - Start);
+      Ver->Section = idx;
+   }
+
    Ver->MultiArch = ParseMultiArch(true);
    // Archive Size
    Ver->Size = Section.FindULL("Size");
@@ -155,10 +150,8 @@ bool debListParser::NewVersion(pkgCache::VerIterator &Ver)
    Ver->InstalledSize *= 1024;
 
    // Priority
-   const char *Start;
-   const char *Stop;
    if (Section.Find("Priority",Start,Stop) == true)
-   {      
+   {
       if (GrabWord(string(Start,Stop-Start),PrioList,Ver->Priority) == false)
 	 Ver->Priority = pkgCache::State::Extra;
    }
@@ -891,7 +884,7 @@ bool debListParser::LoadReleaseInfo(pkgCache::PkgFileIterator &FileI,
 {
    // apt-secure does no longer download individual (per-section) Release
    // file. to provide Component pinning we use the section name now
-   map_stringitem_t const storage = WriteUniqString(component);
+   map_stringitem_t const storage = StoreString(pkgCacheGenerator::MIXED, component);
    FileI->Component = storage;
 
    pkgTagFile TagFile(&File, File.Size());
@@ -900,19 +893,19 @@ bool debListParser::LoadReleaseInfo(pkgCache::PkgFileIterator &FileI,
       return false;
 
    std::string data;
-   #define APT_INRELEASE(TAG, STORE) \
+   #define APT_INRELEASE(TYPE, TAG, STORE) \
    data = Section.FindS(TAG); \
    if (data.empty() == false) \
    { \
-      map_stringitem_t const storage = WriteUniqString(data); \
+      map_stringitem_t const storage = StoreString(pkgCacheGenerator::TYPE, data); \
       STORE = storage; \
    }
-   APT_INRELEASE("Suite", FileI->Archive)
-   APT_INRELEASE("Component", FileI->Component)
-   APT_INRELEASE("Version", FileI->Version)
-   APT_INRELEASE("Origin", FileI->Origin)
-   APT_INRELEASE("Codename", FileI->Codename)
-   APT_INRELEASE("Label", FileI->Label)
+   APT_INRELEASE(MIXED, "Suite", FileI->Archive)
+   APT_INRELEASE(MIXED, "Component", FileI->Component)
+   APT_INRELEASE(VERSION, "Version", FileI->Version)
+   APT_INRELEASE(MIXED, "Origin", FileI->Origin)
+   APT_INRELEASE(MIXED, "Codename", FileI->Codename)
+   APT_INRELEASE(MIXED, "Label", FileI->Label)
    #undef APT_INRELEASE
    Section.FindFlag("NotAutomatic", FileI->Flags, pkgCache::Flag::NotAutomatic);
    Section.FindFlag("ButAutomaticUpgrades", FileI->Flags, pkgCache::Flag::ButAutomaticUpgrades);
diff --git a/apt-pkg/deb/deblistparser.h b/apt-pkg/deb/deblistparser.h
index f5ac47e1e..b55e57d41 100644
--- a/apt-pkg/deb/deblistparser.h
+++ b/apt-pkg/deb/deblistparser.h
@@ -49,7 +49,6 @@ class debListParser : public pkgCacheGenerator::ListParser
    std::vector<std::string> Architectures;
    bool MultiArchEnabled;
 
-   map_stringitem_t UniqFindTagWrite(const char *Tag);
    virtual bool ParseStatus(pkgCache::PkgIterator &Pkg,pkgCache::VerIterator &Ver);
    bool ParseDepends(pkgCache::VerIterator &Ver,const char *Tag,
 		     unsigned int Type);