From a8352c2859a6f84b36fa5cd0af89231cb656b1ce Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Mon, 12 Feb 2024 14:48:48 +0100
Subject: Add public phased update API

This moves the functions of the PhasedUpgrader class into
various other classes so they can be publicly exposed.

This introduces three new functions:

pkgDepCache::PhasingApplied() tells you whether phasing should
be applied to the package.

pkgProblemResolver::KeepPhasedUpdates() keeps back updates that
have phasing applied.

pkgCache::VerIterator::IsSecurityUpdate() determines whether this
version contains security fixes.
---
 apt-pkg/depcache.cc | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 53 insertions(+), 2 deletions(-)

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

diff --git a/apt-pkg/depcache.cc b/apt-pkg/depcache.cc
index 322bf1bbe..c965781a4 100644
--- a/apt-pkg/depcache.cc
+++ b/apt-pkg/depcache.cc
@@ -30,11 +30,12 @@
 
 #include <algorithm>
 #include <iostream>
-#include <memory>
-#include <sstream>
 #include <iterator>
 #include <list>
+#include <memory>
+#include <random>
 #include <set>
+#include <sstream>
 #include <string>
 #include <unordered_map>
 #include <utility>
@@ -141,6 +142,7 @@ struct pkgDepCache::Private
 {
    std::unique_ptr<InRootSetFunc> inRootSetFunc;
    std::unique_ptr<APT::CacheFilter::Matcher> IsAVersionedKernelPackage, IsProtectedKernelPackage;
+   std::string machineID;
 };
 pkgDepCache::pkgDepCache(pkgCache *const pCache, Policy *const Plcy) : group_level(0), Cache(pCache), PkgState(0), DepState(0),
 								       iUsrSize(0), iDownloadSize(0), iInstCount(0), iDelCount(0), iKeepCount(0),
@@ -148,6 +150,7 @@ pkgDepCache::pkgDepCache(pkgCache *const pCache, Policy *const Plcy) : group_lev
 {
    DebugMarker = _config->FindB("Debug::pkgDepCache::Marker", false);
    DebugAutoInstall = _config->FindB("Debug::pkgDepCache::AutoInstall", false);
+   d->machineID = APT::Configuration::getMachineID();
    delLocalPolicy = 0;
    LocalPolicy = Plcy;
    if (LocalPolicy == 0)
@@ -2562,3 +2565,51 @@ bool pkgDepCache::MarkAndSweep()
       return false;
 }
 									/*}}}*/
+
+// DepCache::PhasingApplied					/*{{{*/
+// Check if this version is a phased update that should be ignored, not considering whether
+// it is a security update.
+static bool IsIgnoredPhasedUpdate(std::string machineID, pkgCache::VerIterator const &Ver)
+{
+   if (_config->FindB("APT::Get::Phase-Policy", false))
+      return false;
+
+   // The order and fallbacks for the always/never checks come from update-manager and exist
+   // to preserve compatibility.
+   if (_config->FindB("APT::Get::Always-Include-Phased-Updates",
+		      _config->FindB("Update-Manager::Always-Include-Phased-Updates", false)))
+      return false;
+
+   if (_config->FindB("APT::Get::Never-Include-Phased-Updates",
+		      _config->FindB("Update-Manager::Never-Include-Phased-Updates", false)))
+      return true;
+
+   if (machineID.empty()			 // no machine-id
+       || getenv("SOURCE_DATE_EPOCH") != nullptr // reproducible build - always include
+       || APT::Configuration::isChroot())
+      return false;
+
+   std::string seedStr = std::string(Ver.SourcePkgName()) + "-" + Ver.SourceVerStr() + "-" + machineID;
+   std::seed_seq seed(seedStr.begin(), seedStr.end());
+   std::minstd_rand rand(seed);
+   std::uniform_int_distribution<unsigned int> dist(0, 100);
+
+   return dist(rand) > Ver.PhasedUpdatePercentage();
+}
+
+bool pkgDepCache::PhasingApplied(pkgCache::PkgIterator Pkg) const
+{
+   if (Pkg->CurrentVer == 0)
+      return false;
+   if ((*this)[Pkg].CandidateVer == 0)
+      return false;
+   if ((*this)[Pkg].CandidateVerIter(*Cache).PhasedUpdatePercentage() == 100)
+      return false;
+   if ((*this)[Pkg].CandidateVerIter(*Cache).IsSecurityUpdate())
+      return false;
+   if (!IsIgnoredPhasedUpdate(d->machineID, (*this)[Pkg].CandidateVerIter(*Cache)))
+      return false;
+
+   return true;
+}
+									/*}}}*/
-- 
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