Notify resource caches when pixelref genID goes stale

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"
 
 #ifdef SK_BUILD_FOR_WIN32
     // We don't have SK_BASE_MUTEX_INIT on Windows.
 
     // must be a power-of-2. undef to just use 1 mutex
     #define PIXELREF_MUTEX_RING_COUNT       32
     static SkBaseMutex gPixelRefMutexRing[PIXELREF_MUTEX_RING_COUNT];
 
@@ skipping 189 matching lines @@
 
 void SkPixelRef::addGenIDChangeListener(GenIDChangeListener* listener) {
     if (NULL == listener || !fUniqueGenerationID) {
         // No point in tracking this if we're not going to call it.
         SkDELETE(listener);
         return;
     }
     *fGenIDChangeListeners.append() = listener;
 }
 
+// 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) {
         for (int i = 0; i < fGenIDChangeListeners.count(); i++) {
             fGenIDChangeListeners[i]->onChange();
         }
     }
     // Listeners get at most one shot, so whether these triggered or not, blow them away.
     fGenIDChangeListeners.deleteAll();
+
+    // if fGenerationID is 0, then perhaps we never had one, and we are in the destructor
+    if (fGenerationID) {
+        SkNotifyBitmapGenIDIsStale(fGenerationID);

[mtklein, 2015/02/24 16:43:39]

Just noticed.... this should probably go inside the if (fUniqueGenerationID) {
}, which implies and is stronger than an non-zero fGenerationID.  It's safe to
invalidate the gen ID where you're doing it (it's safe to do it anywhere), but
you may end up purging resources too early unless you're guarded by
fUniqueGenerationID.

[reed2, 2015/02/24 17:44:52]

Ah, thanks. I didn't really know what fUniqueGenerationID meant...

+    }
 }
 
 void SkPixelRef::notifyPixelsChanged() {
 #ifdef SK_DEBUG
     if (fIsImmutable) {
         SkDebugf("========== notifyPixelsChanged called on immutable pixelref");
     }
 #endif
     this->callGenIDChangeListeners();
     this->needsNewGenID();
@@ skipping 21 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;
 }