notify resource caches when pixelref genID goes stale

src/core/SkResourceCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChecksum.h"
 #include "SkResourceCache.h"
 #include "SkMipMap.h"
@@ skipping 276 matching lines @@
         if (!forcePurge && fTotalBytesUsed < byteLimit && fCount < countLimit) {
             break;
         }
 
         Rec* prev = rec->fPrev;
         this->remove(rec);
         rec = prev;
     }
 }
 
+void SkResourceCache::purgeVisitor(const void* nameSpace, VisitorProc proc, void* context) {
+    // go backwards, just like purgeAsNeeded, just to make the code similar.
+    // could iterate either direction and still be correct.
+    Rec* rec = fTail;
+    while (rec) {
+        Rec* prev = rec->fPrev;
+        if (rec->getKey().getNamespace() == nameSpace && !proc(*rec, context)) {
+            this->remove(rec);
+        }
+        rec = prev;
+    }
+}
+
 size_t SkResourceCache::setTotalByteLimit(size_t newLimit) {
     size_t prevLimit = fTotalByteLimit;
     fTotalByteLimit = newLimit;
     if (newLimit < prevLimit) {
         this->purgeAsNeeded();
     }
     return prevLimit;
 }
 
 SkCachedData* SkResourceCache::newCachedData(size_t bytes) {
@@ skipping 197 matching lines @@
 size_t SkResourceCache::SetSingleAllocationByteLimit(size_t size) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->setSingleAllocationByteLimit(size);
 }
 
 size_t SkResourceCache::GetSingleAllocationByteLimit() {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->getSingleAllocationByteLimit();
 }
 
+void SkResourceCache::PurgeVisitor(const void* nameSpace, VisitorProc proc, void* context) {
+    SkAutoMutexAcquire am(gMutex);
+    return get_cache()->purgeVisitor(nameSpace, proc, context);
+}
+
 void SkResourceCache::PurgeAll() {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->purgeAll();
 }
 
 bool SkResourceCache::Find(const Key& key, VisitorProc visitor, void* context) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->find(key, visitor, context);
 }
 
@@ skipping 23 matching lines @@
 }
 
 size_t SkGraphics::SetResourceCacheSingleAllocationByteLimit(size_t newLimit) {
     return SkResourceCache::SetSingleAllocationByteLimit(newLimit);
 }
 
 void SkGraphics::PurgeResourceCache() {
     return SkResourceCache::PurgeAll();
 }