debListParser: Avoid native arch lookup in ParseDepends

We called low-level ParseDepends without an architecture each time,
which means each call looked up the native architecture. Store the
native architecture in the class and use that when calling low-level
ParseDepends from the high-level ParseDepends().

This improves performance for a cache build from 2.7 to 2.5 seconds
for me.

Also avoid a call when stripping multiarch, as the native architecture
is passed in.

2 files changed, 4 insertions, 3 deletions

diff --git a/apt-pkg/deb/deblistparser.cc b/apt-pkg/deb/deblistparser.cc
index e8dff833d..80ca10e37 100644
--- a/apt-pkg/deb/deblistparser.cc
+++ b/apt-pkg/deb/deblistparser.cc
@@ -61,6 +61,7 @@ debListParser::debListParser(FileFd *File) :
    else
       forceEssential.emplace_back("apt");
    forceImportant = _config->FindVector("pkgCacheGen::ForceImportant");
+   myArch = _config->Find("APT::Architecture");
 }
 									/*}}}*/
 // ListParser::Package - Return the package name			/*{{{*/
@@ -621,12 +622,11 @@ const char *debListParser::ParseDepends(const char *Start,const char *Stop,
 
    // We don't want to confuse library users which can't handle MultiArch
    if (StripMultiArch == true) {
-      string const arch = _config->Find("APT::Architecture");
       size_t const found = Package.rfind(':');
       if (found != StringView::npos &&
 	  (Package.substr(found) == ":any" ||
 	   Package.substr(found) == ":native" ||
-	   Package.substr(found +1) == arch))
+	   Package.substr(found +1) == Arch))
 	 Package = Package.substr(0,found);
    }
 
@@ -848,7 +848,7 @@ bool debListParser::ParseDepends(pkgCache::VerIterator &Ver,
       StringView Version;
       unsigned int Op;
 
-      Start = ParseDepends(Start, Stop, Package, Version, Op, false, false, false);
+      Start = ParseDepends(Start, Stop, Package, Version, Op, false, false, false, myArch);
       if (Start == 0)
 	 return _error->Error("Problem parsing dependency %zu",static_cast<size_t>(Key)); // TODO
       size_t const found = Package.rfind(':');
diff --git a/apt-pkg/deb/deblistparser.h b/apt-pkg/deb/deblistparser.h
index 09b56665f..f02252d58 100644
--- a/apt-pkg/deb/deblistparser.h
+++ b/apt-pkg/deb/deblistparser.h
@@ -45,6 +45,7 @@ class APT_HIDDEN debListParser : public pkgCacheListParser
    std::vector<std::string> forceEssential;
    std::vector<std::string> forceImportant;
    std::string MD5Buffer;
+   std::string myArch;
 
    protected:
    pkgTagFile Tags;