Teach Skia to use discardable memory

Source/core/platform/graphics/DeferredImageDecoder.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
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/platform/graphics/DeferredImageDecoder.h"
 
+#include "core/platform/graphics/DecodingImageGenerator.h"
 #include "core/platform/graphics/ImageFrameGenerator.h"
 #include "core/platform/graphics/LazyDecodingPixelRef.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
+#include "third_party/skia/src/lazy/SkDiscardablePixelRef.h"
 #include "wtf/PassOwnPtr.h"
 
 namespace WebCore {
 
 namespace {
 
 // URI label for a lazily decoded SkPixelRef.
 const char labelLazyDecoded[] = "lazy";
 
 } // namespace
 
 bool DeferredImageDecoder::s_enabled = false;
+bool DeferredImageDecoder::s_enabledSkiaDiscardableMemory = false;
 
 DeferredImageDecoder::DeferredImageDecoder(PassOwnPtr<ImageDecoder> actualDecoder)
     : m_allDataReceived(false)
     , m_actualDecoder(actualDecoder)
     , m_orientation(DefaultImageOrientation)
     , m_repetitionCount(cAnimationNone)
 {
 }
 
 DeferredImageDecoder::~DeferredImageDecoder()
@@ skipping 16 matching lines @@
     return bitmap.pixelRef()
         && bitmap.pixelRef()->getURI()
         && !memcmp(bitmap.pixelRef()->getURI(), labelLazyDecoded, sizeof(labelLazyDecoded));
 }
 
 void DeferredImageDecoder::setEnabled(bool enabled)
 {
     s_enabled = enabled;
 }
 
+void DeferredImageDecoder::setEnabledSkiaDiscardableMemory(bool enabled)
+{
+    s_enabledSkiaDiscardableMemory = enabled;
+}
+
 String DeferredImageDecoder::filenameExtension() const
 {
     return m_actualDecoder ? m_actualDecoder->filenameExtension() : m_filenameExtension;
 }
 
 ImageFrame* DeferredImageDecoder::frameBufferAtIndex(size_t index)
 {
     prepareLazyDecodedFrames();
     if (index < m_lazyDecodedFrames.size()) {
         // ImageFrameGenerator has the latest known alpha state. There will
@@ skipping 112 matching lines @@
         || !m_actualDecoder->isSizeAvailable()
         || m_actualDecoder->filenameExtension() == "ico")
         return;
 
     activateLazyDecoding();
 
     const size_t previousSize = m_lazyDecodedFrames.size();
     m_lazyDecodedFrames.resize(m_actualDecoder->frameCount());
     for (size_t i = previousSize; i < m_lazyDecodedFrames.size(); ++i) {
         OwnPtr<ImageFrame> frame(adoptPtr(new ImageFrame()));
-        frame->setSkBitmap(createLazyDecodingBitmap(i));
+        frame->setSkBitmap(createBitmap(i));
         frame->setDuration(m_actualDecoder->frameDurationAtIndex(i));
         frame->setStatus(m_actualDecoder->frameIsCompleteAtIndex(i) ? ImageFrame::FrameComplete : ImageFrame::FramePartial);
         m_lazyDecodedFrames[i] = frame.release();
     }
 
     // The last lazy decoded frame created from previous call might be
     // incomplete so update its state.
     if (previousSize)
         m_lazyDecodedFrames[previousSize - 1]->setStatus(m_actualDecoder->frameIsCompleteAtIndex(previousSize - 1) ? ImageFrame::FrameComplete : ImageFrame::FramePartial);
 
     if (m_allDataReceived) {
         m_repetitionCount = m_actualDecoder->repetitionCount();
         m_actualDecoder.clear();
         m_data = nullptr;
     }
 }
 
+// Creates either a SkBitmap backed by SkDiscardablePixelRef or a SkBitmap using the
+// legacy LazyDecodingPixelRef.
+SkBitmap DeferredImageDecoder::createBitmap(size_t index)
+{
+    // This code is temporary until the transition to SkDiscardablePixelRef is complete.
+    if (s_enabledSkiaDiscardableMemory)
+        return createSkiaDiscardableBitmap(index);
+    return createLazyDecodingBitmap(index);
+}
+
+// Creates a SkBitmap that is backed by SkDiscardablePixelRef.
+SkBitmap DeferredImageDecoder::createSkiaDiscardableBitmap(size_t index)
+{
+    IntSize decodedSize = m_actualDecoder->decodedSize();
+    ASSERT(decodedSize.width() > 0);
+    ASSERT(decodedSize.height() > 0);
+
+    SkImageInfo info;
+    info.fWidth = decodedSize.width();
+    info.fHeight = decodedSize.height();
+    info.fColorType = kBGRA_8888_SkColorType;
+    info.fAlphaType = frameHasAlphaAtIndex(index) ? kPremul_SkAlphaType : kOpaque_SkAlphaType;
+
+    SkBitmap bitmap;
+    bool installed = SkDiscardablePixelRef::Install(new DecodingImageGenerator(m_frameGenerator, info, index), &bitmap);
+    ASSERT_UNUSED(installed, installed);
+    return bitmap;
+}
+
 SkBitmap DeferredImageDecoder::createLazyDecodingBitmap(size_t index)
 {
     IntSize decodedSize = m_actualDecoder->decodedSize();
     ASSERT(decodedSize.width() > 0);
     ASSERT(decodedSize.height() > 0);
 
     // Creates a lazily decoded SkPixelRef that references the entire image without scaling.
     SkBitmap bitmap;
     bitmap.setConfig(SkBitmap::kARGB_8888_Config, decodedSize.width(), decodedSize.height());
     bitmap.setPixelRef(new LazyDecodingPixelRef(m_frameGenerator, index))->unref();
 
     // Use the URI to identify this as a lazily decoded SkPixelRef of type LazyDecodingPixelRef.
     // FIXME: It would be more useful to give the actual image URI.
     bitmap.pixelRef()->setURI(labelLazyDecoded);
 
     // Inform the bitmap that we will never change the pixels. This is a performance hint
     // subsystems that may try to cache this bitmap (e.g. pictures, pipes, gpu, pdf, etc.)
     bitmap.setImmutable();
 
     return bitmap;
 }
 
 bool DeferredImageDecoder::hotSpot(IntPoint& hotSpot) const
 {
     // TODO: Implement.
     return m_actualDecoder ? m_actualDecoder->hotSpot(hotSpot) : false;
 }
 
 } // namespace WebCore