From e1374217a66d1324f3482f6567448f0bc7ef2946 Mon Sep 17 00:00:00 2001
From: spiff <spiff@xbmc.org>
Date: Thu, 21 Mar 2013 14:40:52 +0100
Subject: [PATCH] fixed: prevent infinite loop in add-on dependency checks

---
 xbmc/addons/AddonInstaller.cpp | 21 ++++++++++++++-------
 xbmc/addons/AddonInstaller.h   | 10 ++++++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/xbmc/addons/AddonInstaller.cpp b/xbmc/addons/AddonInstaller.cpp
index b5ba7a0088404..3e655bb8297d7 100644
--- a/xbmc/addons/AddonInstaller.cpp
+++ b/xbmc/addons/AddonInstaller.cpp
@@ -312,6 +312,14 @@ void CAddonInstaller::InstallFromXBMCRepo(const set<CStdString> &addonIDs)
 }
 
 bool CAddonInstaller::CheckDependencies(const AddonPtr &addon)
+{
+  std::vector<std::string> preDeps;
+  preDeps.push_back(addon->ID());
+  return CheckDependencies(addon, preDeps);
+}
+
+bool CAddonInstaller::CheckDependencies(const AddonPtr &addon,
+                                        std::vector<std::string>& preDeps)
 {
   if (!addon.get())
     return true; // a NULL addon has no dependencies
@@ -333,16 +341,15 @@ bool CAddonInstaller::CheckDependencies(const AddonPtr &addon)
         return false;
       }
     }
-    // prevent infinite loops
-    if (dep && dep->ID() == addon->ID())
-    {
-      CLog::Log(LOGERROR, "Addon %s depends on itself, ignoring", addon->ID().c_str());
-      return false;
-    }
     // at this point we have our dep, or the dep is optional (and we don't have it) so check that it's OK as well
     // TODO: should we assume that installed deps are OK?
-    if (dep && !CheckDependencies(dep))
+    if (dep && 
+       std::find(preDeps.begin(), preDeps.end(), dep->ID()) == preDeps.end() &&
+       !CheckDependencies(dep, preDeps))
+    {
       return false;
+    }
+    preDeps.push_back(dep->ID());
   }
   return true;
 }
diff --git a/xbmc/addons/AddonInstaller.h b/xbmc/addons/AddonInstaller.h
index b0ff2bd8ad324..5df69fbad8550 100644
--- a/xbmc/addons/AddonInstaller.h
+++ b/xbmc/addons/AddonInstaller.h
@@ -122,6 +122,16 @@ class CAddonInstaller : public IJobCallback
    */
   bool DoInstall(const ADDON::AddonPtr &addon, const CStdString &hash = "", bool update = false, const CStdString &referer = "", bool background = true);
 
+  /*! \brief Check whether dependencies of an addon exist or are installable.
+   Iterates through the addon's dependencies, checking they're installed or installable.
+   Each dependency must also satisfies CheckDependencies in turn.
+   \param addon the addon to check
+   \param preDeps previous dependencies encountered during recursion. aids in avoiding infinite recursion
+   \return true if dependencies are available, false otherwise.
+   */
+  bool CheckDependencies(const ADDON::AddonPtr &addon,
+                         std::vector<std::string>& preDeps);
+
   void PrunePackageCache();
   int64_t EnumeratePackageFolder(std::map<CStdString,CFileItemList*>& result);