notify resource caches when pixelref genID goes stale

src/core/SkBitmapCache.cpp

Index: src/core/SkBitmapCache.cpp
diff --git a/src/core/SkBitmapCache.cpp b/src/core/SkBitmapCache.cpp
index 3af582232ba9b8eb0b0014874c015d7eaa2d0c96..4ce7e898f2c935e158905808f6684e68480996e4 100644
--- a/src/core/SkBitmapCache.cpp
+++ b/src/core/SkBitmapCache.cpp
@@ -33,11 +33,11 @@ static unsigned gBitmapKeyNamespaceLabel;
 
 struct BitmapKey : public SkResourceCache::Key {
 public:
-    BitmapKey(uint32_t genID, SkScalar scaleX, SkScalar scaleY, const SkIRect& bounds)
-    : fGenID(genID)
-    , fScaleX(scaleX)
-    , fScaleY(scaleY)
-    , fBounds(bounds)
+    BitmapKey(uint32_t genID, SkScalar sx, SkScalar sy, const SkIRect& bounds)
+        : fGenID(genID)
+        , fScaleX(sx)
+        , fScaleY(sy)
+        , fBounds(bounds)
     {
         this->init(&gBitmapKeyNamespaceLabel,
                    sizeof(fGenID) + sizeof(fScaleX) + sizeof(fScaleY) + sizeof(fBounds));
@@ -49,8 +49,6 @@ public:
     SkIRect     fBounds;
 };
 
-//////////////////////////////////////////////////////////////////////////////////////////
-
 struct BitmapRec : public SkResourceCache::Rec {
     BitmapRec(uint32_t genID, SkScalar scaleX, SkScalar scaleY, const SkIRect& bounds,
               const SkBitmap& result)
@@ -58,9 +56,6 @@ struct BitmapRec : public SkResourceCache::Rec {
         , fBitmap(result)
     {}
 
-    BitmapKey   fKey;
-    SkBitmap    fBitmap;
-
     const Key& getKey() const SK_OVERRIDE { return fKey; }
     size_t bytesUsed() const SK_OVERRIDE { return sizeof(fKey) + fBitmap.getSize(); }
 
@@ -72,6 +67,21 @@ struct BitmapRec : public SkResourceCache::Rec {
         result->lockPixels();
         return SkToBool(result->getPixels());
     }
+
+    static SkResourceCache::PurgeVisitorResult PurgeGenID(const SkResourceCache::Rec& baseRec,
+                                                          void* contextGenID) {
+        const BitmapRec& rec = static_cast<const BitmapRec&>(baseRec);
+        uintptr_t genID = (uintptr_t)contextGenID;
+        if (rec.fKey.fGenID == genID) {
+            return SkResourceCache::kPurgeAndContinue_PurgeVisitorResult;
+        } else {
+            return SkResourceCache::kRetainAndContinue_PurgeVisitorResult;
+        }
+    }
+
+private:
+    BitmapKey   fKey;
+    SkBitmap    fBitmap;
 };
 } // namespace
 
@@ -125,11 +135,31 @@ bool SkBitmapCache::Add(uint32_t genID, const SkIRect& subset, const SkBitmap& r
         return true;
     }
 }
+
+void SkBitmapCache::NotifyGenIDStale(uint32_t genID) {
+    SkResourceCache::Purge(&gBitmapKeyNamespaceLabel, BitmapRec::PurgeGenID,
+                           (void*)((uintptr_t)genID));
+}
+
 //////////////////////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////////////////
+
+namespace {
+static unsigned gMipMapKeyNamespaceLabel;
+
+struct MipMapKey : public SkResourceCache::Key {
+public:
+    MipMapKey(uint32_t genID, const SkIRect& bounds) : fGenID(genID), fBounds(bounds) {
+        this->init(&gMipMapKeyNamespaceLabel, sizeof(fGenID) + sizeof(fBounds));
+    }
+
+    uint32_t    fGenID;
+    SkIRect     fBounds;
+};
 
 struct MipMapRec : public SkResourceCache::Rec {
     MipMapRec(const SkBitmap& src, const SkMipMap* result)
-        : fKey(src.getGenerationID(), 0, 0, get_bounds_from_bitmap(src))
+        : fKey(src.getGenerationID(), get_bounds_from_bitmap(src))
         , fMipMap(result)
     {
         fMipMap->attachToCacheAndRef();
@@ -156,14 +186,26 @@ struct MipMapRec : public SkResourceCache::Rec {
         return true;
     }
 
+    static SkResourceCache::PurgeVisitorResult PurgeGenID(const SkResourceCache::Rec& baseRec,
+                                                          void* contextGenID) {
+        const MipMapRec& rec = static_cast<const MipMapRec&>(baseRec);
+        uintptr_t genID = (uintptr_t)contextGenID;
+        if (rec.fKey.fGenID == genID) {
+            return SkResourceCache::kPurgeAndContinue_PurgeVisitorResult;
+        } else {
+            return SkResourceCache::kRetainAndContinue_PurgeVisitorResult;
+        }
+    }
+
 private:
-    BitmapKey       fKey;
+    MipMapKey       fKey;
     const SkMipMap* fMipMap;
 };
+}
 
 const SkMipMap* SkMipMapCache::FindAndRef(const SkBitmap& src, SkResourceCache* localCache) {
     BitmapKey key(src.getGenerationID(), 0, 0, get_bounds_from_bitmap(src));
-    const SkMipMap* result;
+    const SkMipMap* result = NULL;  // if we never get called, we want to see a NULL.
 
     if (!CHECK_LOCAL(localCache, find, Find, key, MipMapRec::Visitor, &result)) {
         result = NULL;
@@ -185,3 +227,7 @@ const SkMipMap* SkMipMapCache::AddAndRef(const SkBitmap& src, SkResourceCache* l
     return mipmap;
 }
 
+void SkMipMapCache::NotifyGenIDStale(uint32_t genID) {
+    SkResourceCache::Purge(&gMipMapKeyNamespaceLabel, MipMapRec::PurgeGenID,
+                           (void*)((uintptr_t)genID));
+}