Bug 757347; Add a cache for image containers. r=roc

layout/base/MaskLayerImageCache.cpp

@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MaskLayerImageCache.h"
+
+using namespace mozilla::layers;
+
+namespace mozilla {
+
+/* static */ PLDHashOperator
+MaskLayerImageCache::SweepFunc(MaskLayerImageEntry* aEntry,
+                               void* aUserArg)
+{
+  const MaskLayerImageCache::MaskLayerImageKey* key = aEntry->mKey;
+
+  if (key->mLayerCount == 0) {
+    return PL_DHASH_REMOVE;
+  }
+
+  return PL_DHASH_NEXT;
+}
+
+void
+MaskLayerImageCache::Sweep() 
+{
+  mMaskImageContainers.EnumerateEntries(SweepFunc, nsnull);
+}
+
+ImageContainer*
+MaskLayerImageCache::FindImageFor(const MaskLayerImageKey** aKey)
+{
+  if (MaskLayerImageEntry* entry = mMaskImageContainers.GetEntry(**aKey)) {
+    *aKey = entry->mKey.get();
+    return entry->mContainer;
+  }
+
+  return nsnull;
+}
+
+void
+MaskLayerImageCache::PutImage(const MaskLayerImageKey* aKey, ImageContainer* aContainer)
+{
+  MaskLayerImageEntry* entry = mMaskImageContainers.PutEntry(*aKey);
+  entry->mContainer = aContainer;
+}
+
+}