Eliminate copies of encoded image data

third_party/WebKit/Source/platform/exported/WebImage.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * 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 "public/platform/WebImage.h"
 
 #include "platform/SharedBuffer.h"
 #include "platform/graphics/Image.h"
 #include "platform/image-decoders/ImageDecoder.h"
+#include "platform/image-decoders/SharedBufferSegmentReader.h"
 #include "public/platform/WebData.h"
 #include "public/platform/WebSize.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/Vector.h"
 #include <algorithm>
 
 namespace blink {
 
 WebImage WebImage::fromData(const WebData& data, const WebSize& desiredSize)
 {
     RefPtr<SharedBuffer> buffer = PassRefPtr<SharedBuffer>(data);
-    OwnPtr<ImageDecoder> decoder(ImageDecoder::create(*buffer.get(), ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored));
+    RefPtr<SharedBufferSegmentReader> segmentReader = adoptRef(new SharedBufferSegmentReader(buffer));
+    OwnPtr<ImageDecoder> decoder(ImageDecoder::create(*segmentReader.get(), ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored));
     if (!decoder)
         return WebImage();
 
-    decoder->setData(buffer.get(), true);
+    decoder->setData(segmentReader.get(), true);
     if (!decoder->isSizeAvailable())
         return WebImage();
 
     // Frames are arranged by decreasing size, then decreasing bit depth.
     // Pick the frame closest to |desiredSize|'s area without being smaller,
     // which has the highest bit depth.
     const size_t frameCount = decoder->frameCount();
     size_t index = 0; // Default to first frame if none are large enough.
     int frameAreaAtIndex = 0;
     for (size_t i = 0; i < frameCount; ++i) {
@@ skipping 19 matching lines @@
 
     return WebImage(frame->bitmap());
 }
 
 WebVector<WebImage> WebImage::framesFromData(const WebData& data)
 {
     // This is to protect from malicious images. It should be big enough that it's never hit in pracice.
     const size_t maxFrameCount = 8;
 
     RefPtr<SharedBuffer> buffer = PassRefPtr<SharedBuffer>(data);
-    OwnPtr<ImageDecoder> decoder(ImageDecoder::create(*buffer.get(), ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored));
+    RefPtr<SharedBufferSegmentReader> segmentReader = adoptRef(new SharedBufferSegmentReader(buffer));
+    OwnPtr<ImageDecoder> decoder(ImageDecoder::create(*segmentReader.get(), ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileIgnored));
     if (!decoder)
         return WebVector<WebImage>();
 
-    decoder->setData(buffer.get(), true);
+    decoder->setData(segmentReader.get(), true);
     if (!decoder->isSizeAvailable())
         return WebVector<WebImage>();
 
     // Frames are arranged by decreasing size, then decreasing bit depth.
     // Keep the first frame at every size, has the highest bit depth.
     const size_t frameCount = decoder->frameCount();
     IntSize lastSize;
 
     Vector<WebImage> frames;
     for (size_t i = 0; i < std::min(frameCount, maxFrameCount); ++i) {
@@ skipping 37 matching lines @@
 WebImage::WebImage(const PassRefPtr<Image>& image)
 {
     if (!image)
         return;
 
     if (RefPtr<SkImage> skImage = image->imageForCurrentFrame())
         skImage->asLegacyBitmap(&m_bitmap, SkImage::kRO_LegacyBitmapMode);
 }
 
 } // namespace blink