From 11917fa559c6c9bc5b0993b435f295de06bd161c Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Thu, 13 Mar 2025 15:15:58 +0100
Subject: 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...
---
 apt-pkg/edsp.cc | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'apt-pkg/edsp.cc')

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,
-- 
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