edsp: Add functionality to only write relevant packages

Add a variant of WriteLimitedScenario that does not take a pkgset,
but creates one on the fly based on the transitive closure of installed
packages, to be installed packages, and their dependencies and provides.

This includes more packages than strictly necessary, i.e. we do not
really need to include foo just because a package we want to install
Conflicts with it, but oh well, this is easy to read.

Trying to extend the filtering is hard as the dependencies being written
are also filtered...

1 files changed, 30 insertions, 0 deletions

diff --git a/apt-pkg/edsp.cc b/apt-pkg/edsp.cc
index 88569d3c4..2e6ef6271 100644
--- a/apt-pkg/edsp.cc
+++ b/apt-pkg/edsp.cc
@@ -327,6 +327,36 @@ bool EDSP::WriteLimitedScenario(pkgDepCache &Cache, FileFd &output,
       Progress->Done();
    return Okay;
 }
+
+static void MarkPackage(std::vector<bool> &pkgset, pkgCache::PkgIterator pkg)
+{
+   if (pkgset[pkg->ID])
+      return;
+   pkgset[pkg->ID] = true;
+   for (auto ver = pkg.VersionList(); not ver.end(); ++ver)
+   {
+      for (auto P = ver.ProvidesList(); not P.end(); ++P)
+	 MarkPackage(pkgset, P.ParentPkg());
+      for (auto D = ver.DependsList(); not D.end(); ++D)
+      {
+	 std::unique_ptr<pkgCache::Version *[]> targets(D.AllTargets());
+	 for (size_t i = 0; targets[i] != 0; ++i)
+	    MarkPackage(pkgset, pkgCache::VerIterator(*ver.Cache(), targets[i]).ParentPkg());
+
+	 MarkPackage(pkgset, D.TargetPkg());
+      }
+   }
+}
+
+bool EDSP::WriteLimitedScenario(pkgDepCache &Cache, FileFd &output,
+				OpProgress *Progress)
+{
+   std::vector<bool> pkgset(Cache.Head().PackageCount);
+   for (auto Pkg = Cache.PkgBegin(); not Pkg.end(); ++Pkg)
+      if (Cache[Pkg].Install() || Pkg->CurrentVer)
+	 MarkPackage(pkgset, Pkg);
+   return WriteLimitedScenario(Cache, output, pkgset, Progress);
+}
 									/*}}}*/
 // EDSP::WriteRequest - to the given file descriptor			/*{{{*/
 bool EDSP::WriteRequest(pkgDepCache &Cache, FileFd &output,