only notify bitmaps that have been added to the cache

src/core/SkPixelRef.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapCache.h"
 #include "SkPixelRef.h"
 #include "SkThread.h"
@@ skipping 82 matching lines @@
     , fStableID(SkNextPixelRefGenerationID())
 #endif
 
 {
     this->setMutex(NULL);
     fRec.zero();
     fLockCount = 0;
     this->needsNewGenID();
     fIsImmutable = false;
     fPreLocked = false;
+    fAddedToCache.store(false);
 }
 
 
 SkPixelRef::SkPixelRef(const SkImageInfo& info, SkBaseMutex* mutex)
     : fInfo(validate_info(info))
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     , fStableID(SkNextPixelRefGenerationID())
 #endif
 {
     this->setMutex(mutex);
     fRec.zero();
     fLockCount = 0;
     this->needsNewGenID();
     fIsImmutable = false;
     fPreLocked = false;
+    fAddedToCache.store(false);
 }
 
 SkPixelRef::~SkPixelRef() {
     this->callGenIDChangeListeners();
 }
 
 void SkPixelRef::needsNewGenID() {
     fGenerationID.store(0);
     fUniqueGenerationID.store(false);
 }
@@ skipping 90 matching lines @@
 }
 
 // we need to be called *before* the genID gets changed or zerod
 void SkPixelRef::callGenIDChangeListeners() {
     // We don't invalidate ourselves if we think another SkPixelRef is sharing our genID.
     if (fUniqueGenerationID.load()) {
         for (int i = 0; i < fGenIDChangeListeners.count(); i++) {
             fGenIDChangeListeners[i]->onChange();
         }
 
-        // If we can flag the pixelref somehow whenever it was actually added to the cache,
-        // perhaps it would be nice to only call this notifier in that case. For now we always
-        // call it, since we don't know if it was cached or not.
-        SkNotifyBitmapGenIDIsStale(this->getGenerationID());
+        // TODO: SkAtomic could add "old_value = atomic.xchg(new_value)" to make this clearer.
+        if (fAddedToCache.load()) {
+            SkNotifyBitmapGenIDIsStale(this->getGenerationID());
+            fAddedToCache.store(false);
+        }
     }
     // Listeners get at most one shot, so whether these triggered or not, blow them away.
     fGenIDChangeListeners.deleteAll();
 }
 
 void SkPixelRef::notifyPixelsChanged() {
 #ifdef SK_DEBUG
     if (fIsImmutable) {
         SkDebugf("========== notifyPixelsChanged called on immutable pixelref");
     }
@@ skipping 24 matching lines @@
 
 bool SkPixelRef::onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
                                  SkYUVColorSpace* colorSpace) {
     return false;
 }
 
 size_t SkPixelRef::getAllocatedSizeInBytes() const {
     return 0;
 }