Teach Skia to use discardable memory

Source/core/platform/graphics/DecodingImageGenerator.cpp

Index: Source/core/platform/graphics/DecodingImageGenerator.cpp
diff --git a/Source/core/platform/graphics/DecodingImageGenerator.cpp b/Source/core/platform/graphics/DecodingImageGenerator.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..6b10731bdabafac52b2e08af20072e1c42fb0074
--- /dev/null
+++ b/Source/core/platform/graphics/DecodingImageGenerator.cpp
@@ -0,0 +1,82 @@
+/*
+ * 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 AND ITS CONTRIBUTORS "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 OR ITS 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/DecodingImageGenerator.h"
+
+#include "SkData.h"
+#include "SkImageInfo.h"
+#include "core/platform/graphics/ImageFrameGenerator.h"
+#include "platform/SharedBuffer.h"
+#include "platform/TraceEvent.h"
+
+namespace WebCore {
+
+DecodingImageGenerator::DecodingImageGenerator(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkImageInfo& info, size_t index)
+    : m_frameGenerator(frameGenerator)
+    , m_imageInfo(info)
+    , m_frameIndex(index)
+{
+}
+
+DecodingImageGenerator::~DecodingImageGenerator()
+{
+}
+
+SkData* DecodingImageGenerator::refEncodedData()
+{
+    // FIXME: If the image has been clipped or scaled, do not return the original
+    // encoded data, since on playback it will not be known how the clipping/scaling
+    // was done.
+    RefPtr<SharedBuffer> buffer = 0;
+    bool allDataReceived = false;
+    m_frameGenerator->copyData(&buffer, &allDataReceived);
+    if (buffer && allDataReceived) {
+        SkData* skdata = SkData::NewWithCopy(buffer->data(), buffer->size());

[Stephen White, 2013/12/05 21:52:14]

Nit: no need for the temporary; could just be

return SkData::NewWithCopy(buffer->data(), buffer->size());

[Alpha Left Google, 2013/12/08 00:30:11]

Done.

+        return skdata;
+    }
+    return 0;
+}
+
+bool DecodingImageGenerator::getInfo(SkImageInfo* info)
+{
+    *info = m_imageInfo;
+    return true;
+}
+
+bool DecodingImageGenerator::getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes)
+{
+    TRACE_EVENT1("webkit", "DecodingImageGenerator::getPixels", "index", static_cast<int>(m_frameIndex));
+
+    // Implementation doesn't support scaling yet so make sure we're not given
+    // a different size.
+    ASSERT(info.fWidth == m_imageInfo.fWidth);
+    ASSERT(info.fHeight == m_imageInfo.fHeight);
+    ASSERT(info.fColorType == m_imageInfo.fColorType);
+    ASSERT(info.fAlphaType == m_imageInfo.fAlphaType);
+    return m_frameGenerator->decodeAndScale(m_imageInfo, m_frameIndex, pixels, rowBytes);
+}
+
+} // namespace blink