From a249b3e6fd798935a02b769149c9791a6fa6ef16 Mon Sep 17 00:00:00 2001
From: David Kalnischkies <david@kalnischkies.de>
Date: Thu, 21 Jan 2016 23:22:00 +0100
Subject: reimplement build-dep via apts normal resolver
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build-dep was implemented by parsing the build-dependencies of a package
and figuring out which packages to install/remove based on this. That
means that for the first level of dependencies build-dep was
implementing its very own resolver with all the benefits (aka: bugs)
this gives us for not using the existing resolver for all levels.

Making this work involves generating a dummy binary package with fitting
Depends and Conflicts and as we can't create them out of thin air the
cache generation needs to be involved so we end up writing a Packages
file which we want to parse – after we have parsed the other Packages
files already. With .dsc/.deb files we could add them before we started
parsing anything.

With a bit of care we can avoid generating too much data we have to
throw away again (as many parts assume that e.g. the count of packages
doesn't change midair), so that on a speed front there shouldn't be
much of a difference, but output can be slightly confusing as if we have
a completely valid cache on disk the "Reading package lists... Done" is
printed two times – but apt is pretty quick about it in that case.

Closes: #137560, #444930, #489911, #583914, #728317, #812173
---
 apt-pkg/deb/debindexfile.cc | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'apt-pkg/deb/debindexfile.cc')

diff --git a/apt-pkg/deb/debindexfile.cc b/apt-pkg/deb/debindexfile.cc
index c11efd0ae..84dabc06b 100644
--- a/apt-pkg/deb/debindexfile.cc
+++ b/apt-pkg/deb/debindexfile.cc
@@ -297,6 +297,39 @@ std::string debDebianSourceDirIndex::GetComponent() const
    return "local-control";
 }
 									/*}}}*/
+// String Package Index - a string of Packages file content		/*{{{*/
+std::string debStringPackageIndex::GetArchitecture() const
+{
+   return std::string();
+}
+std::string debStringPackageIndex::GetComponent() const
+{
+   return "apt-tmp-index";
+}
+uint8_t debStringPackageIndex::GetIndexFlags() const
+{
+   return pkgCache::Flag::NotSource;
+}
+const pkgIndexFile::Type *debStringPackageIndex::GetType() const
+{
+   return pkgIndexFile::Type::GetType("Debian Package Index");
+}
+debStringPackageIndex::debStringPackageIndex(std::string const &content) :
+   pkgDebianIndexRealFile("", false), d(NULL)
+{
+   char fn[1024];
+   std::string const tempdir = GetTempDir();
+   snprintf(fn, sizeof(fn), "%s/%s.XXXXXX", tempdir.c_str(), "apt-tmp-index");
+   int const fd = mkstemp(fn);
+   File = fn;
+   FileFd::Write(fd, content.data(), content.length());
+   close(fd);
+}
+debStringPackageIndex::~debStringPackageIndex()
+{
+   RemoveFile("~debStringPackageIndex", File);
+}
+									/*}}}*/
 
 // Index File types for Debian						/*{{{*/
 class APT_HIDDEN debIFTypeSrc : public pkgIndexFile::Type
-- 
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