Eliminate copies of encoded image data

third_party/WebKit/Source/platform/graphics/DecodingImageGenerator.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 "platform/graphics/DecodingImageGenerator.h"
 
 #include "platform/PlatformInstrumentation.h"
 #include "platform/SharedBuffer.h"
 #include "platform/TraceEvent.h"
 #include "platform/graphics/ImageFrameGenerator.h"
 #include "platform/image-decoders/ImageDecoder.h"
+#include "platform/image-decoders/SegmentReader.h"
 #include "third_party/skia/include/core/SkData.h"
 
 namespace blink {
 
-DecodingImageGenerator::DecodingImageGenerator(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkImageInfo& info, size_t index)
+DecodingImageGenerator::DecodingImageGenerator(PassRefPtr<ImageFrameGenerator> frameGenerator, const SkImageInfo& info, PassRefPtr<SegmentReader> data, bool allDataReceived, size_t index)
     : SkImageGenerator(info)
     , m_frameGenerator(frameGenerator)
+    , m_data(data)
+    , m_allDataReceived(allDataReceived)
     , m_frameIndex(index)
     , m_generationId(0)
     , m_canYUVDecode(false)
 {
 }
 
 DecodingImageGenerator::~DecodingImageGenerator()
 {
 }
 
 SkData* DecodingImageGenerator::onRefEncodedData()
 {
     TRACE_EVENT0("blink", "DecodingImageGenerator::refEncodedData");
 
-    return m_frameGenerator->refEncodedData();
+    if (!m_allDataReceived)
+        return nullptr;
+
+    return m_data->getAsSkData().leakRef();

[Peter Kasting, 2016/03/25 06:24:36]

Nit: Shorter:

    return m_allDataReceived ? m_data->getAsSkData().leakRef() : nullptr;

[scroggo, 2016/03/25 15:49:52]

Done.

 }
 
 bool DecodingImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, SkPMColor table[], int* tableCount)
 {
     TRACE_EVENT1("blink", "DecodingImageGenerator::getPixels", "frame index", static_cast<int>(m_frameIndex));
 
     // Implementation doesn't support scaling yet so make sure we're not given a different size.
     if (info.width() != getInfo().width() || info.height() != getInfo().height())
         return false;
 
     if (info.colorType() != getInfo().colorType()) {
         // blink::ImageFrame may have changed the owning SkBitmap to kOpaque_SkAlphaType after fully decoding the image frame,
         // so if we see a request for opaque, that is ok even if our initial alpha type was not opaque.
         return false;
     }
 
     PlatformInstrumentation::willDecodeLazyPixelRef(m_generationId);
-    bool decoded = m_frameGenerator->decodeAndScale(m_frameIndex, getInfo(), pixels, rowBytes);
+    bool decoded = m_frameGenerator->decodeAndScale(m_data.get(), m_allDataReceived, m_frameIndex, getInfo(), pixels, rowBytes);
     PlatformInstrumentation::didDecodeLazyPixelRef();
 
     return decoded;
 }
 
 bool DecodingImageGenerator::onQueryYUV8(SkYUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const
 {
-    if (!m_canYUVDecode)
+    // YUV decoding does not currently support progressive decoding. See comment in ImageFrameGenerator.h

[Peter Kasting, 2016/03/25 06:24:36]

Nit: Trailing period (2 places)

[scroggo, 2016/03/25 15:49:52]

Done.

+    if (!m_canYUVDecode || !m_allDataReceived)
         return false;
 
     TRACE_EVENT1("blink", "DecodingImageGenerator::queryYUV8", "sizes", static_cast<int>(m_frameIndex));
 
     if (colorSpace)
         *colorSpace = kJPEG_SkYUVColorSpace;
 
-    return m_frameGenerator->getYUVComponentSizes(sizeInfo);
+    return m_frameGenerator->getYUVComponentSizes(m_data.get(), sizeInfo);
 }
 
 bool DecodingImageGenerator::onGetYUV8Planes(const SkYUVSizeInfo& sizeInfo, void* planes[3])
 {
-    ASSERT(m_canYUVDecode);
+    // YUV decoding does not currently support progressive decoding. See comment in ImageFrameGenerator.h
+    ASSERT(m_canYUVDecode && m_allDataReceived);
 
     TRACE_EVENT1("blink", "DecodingImageGenerator::getYUV8Planes", "frame index", static_cast<int>(m_frameIndex));
 
     PlatformInstrumentation::willDecodeLazyPixelRef(m_generationId);
-    bool decoded = m_frameGenerator->decodeToYUV(m_frameIndex, sizeInfo.fSizes, planes, sizeInfo.fWidthBytes);
+    bool decoded = m_frameGenerator->decodeToYUV(m_data.get(), m_frameIndex, sizeInfo.fSizes, planes, sizeInfo.fWidthBytes);
     PlatformInstrumentation::didDecodeLazyPixelRef();
 
     return decoded;
 }
 
 SkImageGenerator* DecodingImageGenerator::create(SkData* data)
 {
-    RefPtr<SharedBuffer> buffer = SharedBuffer::create(data->bytes(), data->size());
-
     // We just need the size of the image, so we have to temporarily create an ImageDecoder. Since
     // we only need the size, it doesn't really matter about premul or not, or gamma settings.
-    OwnPtr<ImageDecoder> decoder = ImageDecoder::create(*buffer.get(), ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileApplied);
+    OwnPtr<ImageDecoder> decoder = ImageDecoder::create(static_cast<const char*>(data->data()), data->size(),
+        ImageDecoder::AlphaPremultiplied, ImageDecoder::GammaAndColorProfileApplied);
     if (!decoder)
         return 0;
 
-    decoder->setData(buffer.get(), true);
+    RefPtr<SegmentReader> segmentReader = SegmentReader::createFromSkData(data);
+    decoder->setData(segmentReader.get(), true);
     if (!decoder->isSizeAvailable())
         return 0;
 
     const IntSize size = decoder->size();
     const SkImageInfo info = SkImageInfo::MakeN32Premul(size.width(), size.height());
 
-    RefPtr<ImageFrameGenerator> frame = ImageFrameGenerator::create(SkISize::Make(size.width(), size.height()), buffer, true, false);
+    RefPtr<ImageFrameGenerator> frame = ImageFrameGenerator::create(SkISize::Make(size.width(), size.height()), false);
     if (!frame)
         return 0;
 
-    return new DecodingImageGenerator(frame, info, 0);
+    return new DecodingImageGenerator(frame, info, segmentReader.release(), true, 0);
 }
 
 } // namespace blink