Deferred image decoding to support animated GIFs

Source/core/platform/graphics/chromium/LazyDecodingPixelRef.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 12 matching lines @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/platform/graphics/chromium/LazyDecodingPixelRef.h"
 
 #include "SkData.h"
 #include "core/platform/chromium/TraceEvent.h"
 #include "core/platform/graphics/chromium/ImageDecodingStore.h"
 #include "core/platform/graphics/chromium/ImageFrameGenerator.h"
-#include <wtf/MainThread.h>
 
 namespace WebCore {
 
-LazyDecodingPixelRef::LazyDecodingPixelRef(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkISize& scaledSize, const SkIRect& scaledSubset)
+LazyDecodingPixelRef::LazyDecodingPixelRef(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkISize& scaledSize, size_t index, const SkIRect& scaledSubset)
     : m_frameGenerator(frameGenerator)
+    , m_frameIndex(index)
     , m_scaledSize(scaledSize)
     , m_scaledSubset(scaledSubset)
     , m_lockedCachedImage(0)
 {
 }
 
 LazyDecodingPixelRef::~LazyDecodingPixelRef()
 {
 }
 
@@ skipping 20 matching lines @@
         SkData* skdata = SkData::NewWithCopy((void*)buffer->data(), buffer->size());
         return skdata;
     }
     return 0;
 }
 
 void* LazyDecodingPixelRef::onLockPixels(SkColorTable**)
 {
     TRACE_EVENT_ASYNC_BEGIN0("webkit", "LazyDecodingPixelRef::lockPixels", this);
 
-    m_mutex.lock();
     ASSERT(!m_lockedCachedImage);
 
-    if (!ImageDecodingStore::instance()->lockCache(m_frameGenerator.get(), m_scaledSize, 0, &m_lockedCachedImage))
+    if (!ImageDecodingStore::instance()->lockCache(m_frameGenerator.get(), m_scaledSize, m_frameIndex, &m_lockedCachedImage))
         m_lockedCachedImage = 0;
 
     // Use ImageFrameGenerator to generate the image. It will lock the cache
     // entry for us.
     if (!m_lockedCachedImage)
-        m_lockedCachedImage = m_frameGenerator->decodeAndScale(m_scaledSize);
+        m_lockedCachedImage = m_frameGenerator->decodeAndScale(m_scaledSize, m_frameIndex);
 
     if (!m_lockedCachedImage)
         return 0;
 
     ASSERT(!m_lockedCachedImage->bitmap().isNull());
     ASSERT(m_lockedCachedImage->scaledSize() == m_scaledSize);
     return m_lockedCachedImage->bitmap().getAddr(m_scaledSubset.x(), m_scaledSubset.y());
 }
 
 void LazyDecodingPixelRef::onUnlockPixels()
 {
     if (m_lockedCachedImage) {
         ImageDecodingStore::instance()->unlockCache(m_frameGenerator.get(), m_lockedCachedImage);
         m_lockedCachedImage = 0;
     }
-    m_mutex.unlock();
 
     TRACE_EVENT_ASYNC_END0("webkit", "LazyDecodingPixelRef::lockPixels", this);
 }
 
 bool LazyDecodingPixelRef::onLockPixelsAreWritable() const
 {
     return false;
 }
 
 bool LazyDecodingPixelRef::MaybeDecoded()
 {
-    return ImageDecodingStore::instance()->isCached(m_frameGenerator.get(), m_scaledSize, 0);
+    return ImageDecodingStore::instance()->isCached(m_frameGenerator.get(), m_scaledSize, m_frameIndex);
 }
 
 bool LazyDecodingPixelRef::PrepareToDecode(const LazyPixelRef::PrepareParams& params)
 {
-    // TODO: check if only a particular rect is available in image cache.
-    UNUSED_PARAM(params);
-    const ScaledImageFragment* cachedImage = 0;
-    bool cached = ImageDecodingStore::instance()->lockCache(m_frameGenerator.get(), m_scaledSize, 0, &cachedImage);
-    if (cached)
-        ImageDecodingStore::instance()->unlockCache(m_frameGenerator.get(), cachedImage);
-    return cached;
+    ASSERT(false);
+    return false;
 }
 
 void LazyDecodingPixelRef::Decode()
 {
     lockPixels();
     unlockPixels();
 }
 
 
 } // namespace WebKit