Bug 1126739 - Add locking to SurfaceCache entry points that bypass the public API. r=tn CLOSED TREE a=KWierso

--HG--
extra : rebase_source : 88cf49ab4ccf6949a11b78d2a3c8518a55fa852d

image/src/SurfaceCache.cpp

@@ -362,7 +362,7 @@ public:
   SurfaceCacheImpl(uint32_t aSurfaceCacheExpirationTimeMS,
                    uint32_t aSurfaceCacheDiscardFactor,
                    uint32_t aSurfaceCacheSize)
-    : mExpirationTracker(this, aSurfaceCacheExpirationTimeMS)
+    : mExpirationTracker(aSurfaceCacheExpirationTimeMS)
     , mMemoryPressureObserver(new MemoryPressureObserver)
     , mMutex("SurfaceCache")
     , mDiscardFactor(aSurfaceCacheDiscardFactor)
@@ -742,6 +742,8 @@ public:
                  nsISupports*             aData,
                  bool                     aAnonymize) MOZ_OVERRIDE
   {
+    MutexAutoLock lock(mMutex);
+
     // We have explicit memory reporting for the surface cache which is more
     // accurate than the cost metrics we report here, but these metrics are
     // still useful to report, since they control the cache's behavior.
@@ -809,21 +811,18 @@ private:
 
   struct SurfaceTracker : public nsExpirationTracker<CachedSurface, 2>
   {
-    SurfaceTracker(SurfaceCacheImpl* aCache, uint32_t aSurfaceCacheExpirationTimeMS)
+    SurfaceTracker(uint32_t aSurfaceCacheExpirationTimeMS)
       : nsExpirationTracker<CachedSurface, 2>(aSurfaceCacheExpirationTimeMS)
-      , mCache(aCache)
     { }
 
   protected:
     virtual void NotifyExpired(CachedSurface* aSurface) MOZ_OVERRIDE
     {
-      if (mCache) {
-        mCache->Remove(aSurface);
+      if (sInstance) {
+        MutexAutoLock lock(sInstance->GetMutex());
+        sInstance->Remove(aSurface);
       }
     }
-
-  private:
-    SurfaceCacheImpl* const mCache;  // Weak pointer to owner.
   };
 
   struct MemoryPressureObserver : public nsIObserver
@@ -835,6 +834,7 @@ private:
                        const char16_t*) MOZ_OVERRIDE
     {
       if (sInstance && strcmp(aTopic, "memory-pressure") == 0) {
+        MutexAutoLock lock(sInstance->GetMutex());
         sInstance->DiscardForMemoryPressure();
       }
       return NS_OK;