Remove duplication of encoded image data

third_party/WebKit/Source/platform/graphics/Image.h

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006 Apple Computer, 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 10 matching lines @@
  * 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.
  */
 
 #ifndef Image_h
 #define Image_h
 
 #include "platform/PlatformExport.h"
+#include "platform/SharedBuffer.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/Color.h"
 #include "platform/graphics/GraphicsTypes.h"
 #include "platform/graphics/ImageAnimationPolicy.h"
 #include "platform/graphics/ImageObserver.h"
 #include "platform/graphics/ImageOrientation.h"
 #include "wtf/Assertions.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 #include "wtf/text/WTFString.h"
 
 class SkBitmap;
 class SkCanvas;
 class SkImage;
 class SkMatrix;
 class SkPaint;
 
 namespace blink {
 
 class FloatPoint;
 class FloatRect;
 class FloatSize;
 class GraphicsContext;
 class Length;
-class SharedBuffer;
 class Image;
 
 class PLATFORM_EXPORT Image : public RefCounted<Image> {
     friend class GeneratedImage;
     friend class CrossfadeGeneratedImage;
     friend class GradientGeneratedImage;
     friend class GraphicsContext;
     WTF_MAKE_NONCOPYABLE(Image);
 
 public:
@@ skipping 33 matching lines @@
     int height() const { return size().height(); }
     virtual bool getHotSpot(IntPoint&) const { return false; }
 
     bool setData(PassRefPtr<SharedBuffer> data, bool allDataReceived);
     virtual bool dataChanged(bool /*allDataReceived*/) { return false; }
 
     virtual String filenameExtension() const { return String(); } // null string if unknown
 
     virtual void destroyDecodedData() = 0;
 
-    SharedBuffer* data() { return m_encodedImageData.get(); }
+    virtual PassRefPtr<SharedBuffer> data() { return m_encodedImageData; }

[haraken, 2016/06/23 01:26:41]

Is ScriptStreamer the only reason you want to change the return type to
PassRefPtr? If so, I'd prefer just keeping the old code as is, because it is
important to make sure that Image is the *only* owner of m_encodedImageData. If
the ownership is passed to other callers, we may not be able to release the
underlying SharedBuffer when resetEncodedImageData gets called.

[hajimehoshi, 2016/06/23 09:23:13]

This change is needed since the child class BitmapImage requires this change:
After this CL, a BitmapImage might return a SharedBuffer which is not owned by a
BitmapImage.

 
     // Animation begins whenever someone draws the image, so startAnimation() is not normally called.
     // It will automatically pause once all observers no longer want to render the image anywhere.
     enum CatchUpAnimation { DoNotCatchUp, CatchUp };
     virtual void startAnimation(CatchUpAnimation = CatchUp) { }
     virtual void resetAnimation() {}
 
     // True if this image can potentially animate.
     virtual bool maybeAnimated() { return false; }
 
@@ skipping 42 matching lines @@
     static FloatRect computeSubsetForTile(const FloatRect& tile, const FloatRect& dest,
         const FloatSize& imageSize);
 
 protected:
     Image(ImageObserver* = 0);
 
     void drawTiled(GraphicsContext&, const FloatRect& dstRect, const FloatPoint& srcPoint, const FloatSize& tileSize,
         SkXfermode::Mode, const FloatSize& repeatSpacing);
     void drawTiled(GraphicsContext&, const FloatRect& dstRect, const FloatRect& srcRect, const FloatSize& tileScaleFactor, TileRule hRule, TileRule vRule, SkXfermode::Mode);
 
+    // Releases m_encodedImageData when the subclass can have encoded image data
+    // in another way.
+    void resetEncodedImageData() { m_encodedImageData.release(); }
+
 private:
     RefPtr<SharedBuffer> m_encodedImageData;
     // TODO(Oilpan): consider having Image on the Oilpan heap and
     // turn this into a Member<>.
     //
     // The observer (an ImageResource) is an untraced member, with the ImageResource
     // being responsible of clearing itself out.
     UntracedMember<ImageObserver> m_imageObserver;
     bool m_imageObserverDisabled;
 };
 
 #define DEFINE_IMAGE_TYPE_CASTS(typeName) \
     DEFINE_TYPE_CASTS(typeName, Image, image, image->is##typeName(), image.is##typeName())
 
 } // namespace blink
 
 #endif