Move gif image decoder to SkCodec

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoder.cpp

 /*
  * Copyright (C) 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
  *    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 "platform/image-decoders/gif/GIFImageDecoder.h"
 
-#include "platform/image-decoders/gif/GIFImageReader.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
 #include "wtf/NotFound.h"
 #include "wtf/PtrUtil.h"
 #include <limits>
 
 namespace blink {
 
 GIFImageDecoder::GIFImageDecoder(AlphaOption alphaOption,
                                  const ColorBehavior& colorBehavior,
                                  size_t maxDecodedBytes)
     : ImageDecoder(alphaOption, colorBehavior, maxDecodedBytes),
-      m_repetitionCount(cAnimationLoopOnce) {}
-
-GIFImageDecoder::~GIFImageDecoder() {}
+      m_codec(),
+      m_segmentStream(nullptr) {}
+
+GIFImageDecoder::~GIFImageDecoder() {
+  if (!m_codec) {
+    // if we did not create m_codec and thus did not pass ownership to it
+    if (m_segmentStream) {
+      delete m_segmentStream;
+    }
+  }
+}
 
 void GIFImageDecoder::onSetData(SegmentReader* data) {
-  if (m_reader)
-    m_reader->setData(data);
+  if (!m_segmentStream) {
+    m_segmentStream = new SegmentStream();
+  }
+
+  m_segmentStream->setReader(data, isAllDataReceived());
+
+  // If we don't have a SkCodec yet, create one from the stream
+  if (!m_codec) {
+    m_codec.reset(SkCodec::NewFromStream(m_segmentStream));
+    if (!m_codec) {
+      // m_segmentStream's ownership is passed. It is deleted if SkCodec
+      // creation fails. In this case, release our reference so we can create a
+      // new SegmentStream later.
+      m_segmentStream = nullptr;
+    }
+  }
 }
 
 int GIFImageDecoder::repetitionCount() const {
+  if (!m_codec) {
+    return 0;
+  }
+
   // This value can arrive at any point in the image data stream.  Most GIFs
   // in the wild declare it near the beginning of the file, so it usually is
   // set by the time we've decoded the size, but (depending on the GIF and the
-  // packets sent back by the webserver) not always.  If the reader hasn't
-  // seen a loop count yet, it will return cLoopCountNotSeen, in which case we
-  // should default to looping once (the initial value for
-  // |m_repetitionCount|).
+  // packets sent back by the webserver) not always.
   //
-  // There are some additional wrinkles here. First, ImageSource::clear()
-  // may destroy the reader, making the result from the reader _less_
-  // authoritative on future calls if the recreated reader hasn't seen the
-  // loop count.  We don't need to special-case this because in this case the
-  // new reader will once again return cLoopCountNotSeen, and we won't
-  // overwrite the cached correct value.
-  //
-  // Second, a GIF might never set a loop count at all, in which case we
-  // should continue to treat it as a "loop once" animation.  We don't need
-  // special code here either, because in this case we'll never change
-  // |m_repetitionCount| from its default value.
-  //
-  // Third, we use the same GIFImageReader for counting frames and we might
-  // see the loop count and then encounter a decoding error which happens
-  // later in the stream. It is also possible that no frames are in the
-  // stream. In these cases we should just loop once.
-  if (isAllDataReceived() && parseCompleted() && m_reader->imagesCount() == 1)
-    m_repetitionCount = cAnimationNone;
-  else if (failed() || (m_reader && (!m_reader->imagesCount())))
-    m_repetitionCount = cAnimationLoopOnce;
-  else if (m_reader && m_reader->loopCount() != cLoopCountNotSeen)
-    m_repetitionCount = m_reader->loopCount();
-  return m_repetitionCount;
+  // SkCodec will parse forward in the file if the repetition count has not been
+  // seen yet.
+
+  int repetitionCount = m_codec->getRepetitionCount();
+  switch (repetitionCount) {
+    case 0:
+      return cAnimationNone;
+    case SkCodec::kRepetitionCountInfinite:
+      return cAnimationLoopInfinite;
+    default:
+      return repetitionCount;
+  }
 }
 
 bool GIFImageDecoder::frameIsCompleteAtIndex(size_t index) const {
-  return m_reader && (index < m_reader->imagesCount()) &&
-         m_reader->frameContext(index)->isComplete();
+  if (!m_codec) {
+    return false;
+  }
+
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+  if (frameInfos.size() <= index) {
+    return false;
+  }
+
+  return frameInfos[index].fFullyReceived;
 }
 
 float GIFImageDecoder::frameDurationAtIndex(size_t index) const {
-  return (m_reader && (index < m_reader->imagesCount()) &&
-          m_reader->frameContext(index)->isHeaderDefined())
-             ? m_reader->frameContext(index)->delayTime()
-             : 0;
-}
-
-bool GIFImageDecoder::setFailed() {
-  m_reader.reset();
-  return ImageDecoder::setFailed();
-}
-
-bool GIFImageDecoder::haveDecodedRow(size_t frameIndex,
-                                     GIFRow::const_iterator rowBegin,
-                                     size_t width,
-                                     size_t rowNumber,
-                                     unsigned repeatCount,
-                                     bool writeTransparentPixels) {
-  const GIFFrameContext* frameContext = m_reader->frameContext(frameIndex);
-  // The pixel data and coordinates supplied to us are relative to the frame's
-  // origin within the entire image size, i.e.
-  // (frameContext->xOffset, frameContext->yOffset). There is no guarantee
-  // that width == (size().width() - frameContext->xOffset), so
-  // we must ensure we don't run off the end of either the source data or the
-  // row's X-coordinates.
-  const int xBegin = frameContext->xOffset();
-  const int yBegin = frameContext->yOffset() + rowNumber;
-  const int xEnd = std::min(static_cast<int>(frameContext->xOffset() + width),
-                            size().width());
-  const int yEnd = std::min(
-      static_cast<int>(frameContext->yOffset() + rowNumber + repeatCount),
-      size().height());
-  if (!width || (xBegin < 0) || (yBegin < 0) || (xEnd <= xBegin) ||
-      (yEnd <= yBegin))
-    return true;
-
-  const GIFColorMap::Table& colorTable =
-      frameContext->localColorMap().isDefined()
-          ? frameContext->localColorMap().getTable()
-          : m_reader->globalColorMap().getTable();
-
-  if (colorTable.isEmpty())
-    return true;
-
-  GIFColorMap::Table::const_iterator colorTableIter = colorTable.begin();
-
-  // Initialize the frame if necessary.
-  ImageFrame& buffer = m_frameBufferCache[frameIndex];
-  if (!initFrameBuffer(frameIndex))
-    return false;
-
-  const size_t transparentPixel = frameContext->transparentPixel();
-  GIFRow::const_iterator rowEnd = rowBegin + (xEnd - xBegin);
-  ImageFrame::PixelData* currentAddress = buffer.getAddr(xBegin, yBegin);
-
-  // We may or may not need to write transparent pixels to the buffer.
-  // If we're compositing against a previous image, it's wrong, and if
-  // we're writing atop a cleared, fully transparent buffer, it's
-  // unnecessary; but if we're decoding an interlaced gif and
-  // displaying it "Haeberli"-style, we must write these for passes
-  // beyond the first, or the initial passes will "show through" the
-  // later ones.
-  //
-  // The loops below are almost identical. One writes a transparent pixel
-  // and one doesn't based on the value of |writeTransparentPixels|.
-  // The condition check is taken out of the loop to enhance performance.
-  // This optimization reduces decoding time by about 15% for a 3MB image.
-  if (writeTransparentPixels) {
-    for (; rowBegin != rowEnd; ++rowBegin, ++currentAddress) {
-      const size_t sourceValue = *rowBegin;
-      if ((sourceValue != transparentPixel) &&
-          (sourceValue < colorTable.size())) {
-        *currentAddress = colorTableIter[sourceValue];
-      } else {
-        *currentAddress = 0;
-        m_currentBufferSawAlpha = true;
+  if (!m_codec) {
+    return 0;
+  }
+
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();

[Noel Gordon, 2016/12/21 06:16:56]

Drive by: std:: container types not allowed in platform unless we changed that
requirement.  m_codec->getFrameInfo() seems to force you to use it.

Is there and m_codec-> API to grab info for a particular frame?  Seems
suboptimal to me to have to copy the info for all frames each time we want info
about a particular frame.

[cblume, 2016/12/21 08:18:19]

Having to copy the vector each time definitely isn't ideal.
After seeing it spelled out like this, I believe Leon and I both thought it
might be better for SkCodec to keep a cached copy of the vector and just give us
a reference when we need it.
Perhaps going one step further would be to instead just give us the frame info
and size, which avoids std:: here.

[scroggo_chromium, 2016/12/21 21:25:15]

I do not currently see anything in the blink style guide [1], the Chromium style
guide [2], or the Google style guide [3]. But it must have been desirable to
avoid STL at some point, or we wouldn't have needed WTF. (A search of
third_party/WebKit shows that there are other users [4], although I have not
investigated those.)

To support an API like this (more on that in response to your next comments),
std:: seemed like the only way to go, since we've hidden our array classes in
Skia and Skia cannot depend on WTF.
No. Originally, I proposed an API on SkCodec that looked a little more like
ImageDecoder (e.g. getFrameCount(), getFrameDuration(index))[5], but we thought
it made sense to provide all the data up front, rather than having several
queries.
Agreed [7].


[1] https://www.chromium.org/blink/coding-style
[2]
https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md
[3] https://google.github.io/styleguide/cppguide.html
[4]
https://cs.chromium.org/search/?q=std::vector+file:third_party/WebKit&sq=pack...
[5] https://codereview.chromium.org/2045293002/#ps20001
[6] https://codereview.chromium.org/2045293002/#msg16
[7]
https://codereview.chromium.org/2565323003/diff/1/third_party/WebKit/Source/p...

[scroggo_chromium, 2016/12/22 16:21:31]

Thanks for the pointer - I had not seen that doc.
I've realized something I should have noticed before - we do not need to call
getFrameInfo so often. We should be able to call it once inside
decodeFrameCount.

+  if (frameInfos.size() <= index) {
+    return 0;
+  }
+
+  return frameInfos[index].fDuration;
+}
+
+void GIFImageDecoder::decodeSize() {
+  CHECK(m_codec);
+
+  SkImageInfo imageInfo = m_codec->getInfo();
+  setSize(imageInfo.width(), imageInfo.height());
+}
+
+size_t GIFImageDecoder::decodeFrameCount() {
+  CHECK(m_codec);
+
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+  return frameInfos.size();
+}
+
+void GIFImageDecoder::initializeNewFrame(size_t index) {
+  if (!m_codec) {
+    return;
+  }
+
+  ImageFrame& frame = m_frameBufferCache[index];
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+
+  // FIXME We may not need to fill in all this frame information.
+  // SkCodec doesn't need it. Check if Blink uses it at all.
+  // If Blink does use it, maybe SkCodec can provide it to us.
+  IntSize frameSize = size();
+  frame.setOriginalFrameRect(IntRect(IntPoint(), frameSize));
+  frame.setSizeAndColorSpace(frameSize.width(), frameSize.height(),
+                             colorSpaceForSkImages());
+  frame.setDuration(frameInfos[index].fDuration);
+  // The disposal method is not required any more, but is left in place
+  // for the other image decoders that do not yet rely on SkCodec.
+  // For now, fill it with DisposeKeep.
+  frame.setDisposalMethod(ImageFrame::DisposeKeep);
+  size_t requiredPreviousFrame = frameInfos[index].fRequiredFrame;
+  if (requiredPreviousFrame == SkCodec::kNone) {
+    requiredPreviousFrame = WTF::kNotFound;
+  }
+  frame.setRequiredPreviousFrameIndex(requiredPreviousFrame);
+}
+
+void GIFImageDecoder::decode(size_t index) {
+  if (!m_codec) {
+    return;
+  }
+
+  if (m_frameBufferCache.size() <= index) {
+    // It is a fatal error if all data is received and we have decoded all
+    // frames available but the file is truncated.
+    if (isAllDataReceived()) {
+      setFailed();
+    }
+
+    return;
+  }
+
+  updateAggressivePurging(index);
+
+  SkImageInfo imageInfo = m_codec->getInfo().makeColorType(kN32_SkColorType);
+
+  ImageFrame& frame = m_frameBufferCache[index];
+  size_t requiredPreviousFrameIndex = frame.requiredPreviousFrameIndex();
+
+  SkCodec::Options options;
+  options.fFrameIndex = index;
+  options.fHasPriorFrame = false;
+  if (requiredPreviousFrameIndex != WTF::kNotFound) {
+    options.fHasPriorFrame = true;
+  }
+
+  if (frame.getStatus() == ImageFrame::FrameEmpty) {
+    SkCodec::Result startIncrementalDecodeResult =
+        m_codec->startIncrementalDecode(imageInfo, frame.bitmap().getPixels(),
+                                        frame.bitmap().rowBytes(), &options,
+                                        nullptr, nullptr);
+    switch (startIncrementalDecodeResult) {
+      case SkCodec::kSuccess:
+        break;
+      case SkCodec::kIncompleteInput:
+        return;
+      default:
+        setFailed();
+        return;
+    }
+
+    if (requiredPreviousFrameIndex != WTF::kNotFound) {
+      ImageFrame& requiredPreviousFrame =
+          m_frameBufferCache[requiredPreviousFrameIndex];
+
+      // We try to reuse |requiredPreviousFrame| as starting state to avoid
+      // copying. If canReusePreviousFrameBuffer returns false, we must copy
+      // the data since |requiredPreviousFrame| is necessary to decode this
+      // or later frames. In that case copy the data instead.
+      if ((!canReusePreviousFrameBuffer(index) ||
+           !frame.takeBitmapDataIfWritable(&requiredPreviousFrame)) &&
+          !frame.copyBitmapData(requiredPreviousFrame)) {
+        setFailed();
+        return;
       }
     }
-  } else {
-    for (; rowBegin != rowEnd; ++rowBegin, ++currentAddress) {
-      const size_t sourceValue = *rowBegin;
-      if ((sourceValue != transparentPixel) &&
-          (sourceValue < colorTable.size()))
-        *currentAddress = colorTableIter[sourceValue];
-      else
-        m_currentBufferSawAlpha = true;
-    }
-  }
-
-  // Tell the frame to copy the row data if need be.
-  if (repeatCount > 1)
-    buffer.copyRowNTimes(xBegin, xEnd, yBegin, yEnd);
-
-  buffer.setPixelsChanged(true);
-  return true;
-}
-
-bool GIFImageDecoder::parseCompleted() const {
-  return m_reader && m_reader->parseCompleted();
-}
-
-bool GIFImageDecoder::frameComplete(size_t frameIndex) {
-  // Initialize the frame if necessary.  Some GIFs insert do-nothing frames,
-  // in which case we never reach haveDecodedRow() before getting here.
-  if (!initFrameBuffer(frameIndex))
-    return false;  // initFrameBuffer() has already called setFailed().
-
-  m_frameBufferCache[frameIndex].setStatus(ImageFrame::FrameComplete);
-  if (!m_currentBufferSawAlpha)
-    correctAlphaWhenFrameBufferSawNoAlpha(frameIndex);
-
-  return true;
-}
-
-void GIFImageDecoder::clearFrameBuffer(size_t frameIndex) {
-  if (m_reader &&
-      m_frameBufferCache[frameIndex].getStatus() == ImageFrame::FramePartial) {
-    // Reset the state of the partial frame in the reader so that the frame
-    // can be decoded again when requested.
-    m_reader->clearDecodeState(frameIndex);
-  }
-  ImageDecoder::clearFrameBuffer(frameIndex);
-}
-
-size_t GIFImageDecoder::decodeFrameCount() {
-  parse(GIFFrameCountQuery);
-  // If decoding fails, |m_reader| will have been destroyed.  Instead of
-  // returning 0 in this case, return the existing number of frames.  This way
-  // if we get halfway through the image before decoding fails, we won't
-  // suddenly start reporting that the image has zero frames.
-  return failed() ? m_frameBufferCache.size() : m_reader->imagesCount();
-}
-
-void GIFImageDecoder::initializeNewFrame(size_t index) {
-  ImageFrame* buffer = &m_frameBufferCache[index];
-  const GIFFrameContext* frameContext = m_reader->frameContext(index);
-  buffer->setOriginalFrameRect(
-      intersection(frameContext->frameRect(), IntRect(IntPoint(), size())));
-  buffer->setDuration(frameContext->delayTime());
-  buffer->setDisposalMethod(frameContext->getDisposalMethod());
-  buffer->setRequiredPreviousFrameIndex(
-      findRequiredPreviousFrame(index, false));
-}
-
-void GIFImageDecoder::decode(size_t index) {
-  parse(GIFFrameCountQuery);
-
-  if (failed())
-    return;
-
-  updateAggressivePurging(index);
-
-  Vector<size_t> framesToDecode = findFramesToDecode(index);
-  for (auto i = framesToDecode.rbegin(); i != framesToDecode.rend(); ++i) {
-    if (!m_reader->decode(*i)) {
+  }
+
+  int rowsDecoded = 0;
+  SkCodec::Result incrementalDecodeResult =
+      m_codec->incrementalDecode(&rowsDecoded);
+  switch (incrementalDecodeResult) {
+    case SkCodec::kSuccess:
+      frame.setStatus(ImageFrame::FrameComplete);
+      break;
+    case SkCodec::kIncompleteInput:
+      if (frame.getStatus() == ImageFrame::FrameEmpty && index == 0) {
+        // We want to display the bit of the frame we have decoded only if it is
+        // the first frame of an animation. That means we need to fill the rest
+        // of the image with transparent.
+        IntRect remainingRect = frame.originalFrameRect();
+        remainingRect.setHeight(remainingRect.height() - rowsDecoded);
+        frame.zeroFillFrameRect(remainingRect);
+      }
+
+      frame.setStatus(ImageFrame::FramePartial);
+      break;
+    default:
       setFailed();
       return;
-    }
-
-    // If this returns false, we need more data to continue decoding.
-    if (!postDecodeProcessing(*i))
-      break;
-  }
-
-  // It is also a fatal error if all data is received and we have decoded all
-  // frames available but the file is truncated.
-  if (index >= m_frameBufferCache.size() - 1 && isAllDataReceived() &&
-      m_reader && !m_reader->parseCompleted())
-    setFailed();
-}
-
-void GIFImageDecoder::parse(GIFParseQuery query) {
-  if (failed())
-    return;
-
-  if (!m_reader) {
-    m_reader = WTF::makeUnique<GIFImageReader>(this);
-    m_reader->setData(m_data);
-  }
-
-  if (!m_reader->parse(query))
-    setFailed();
-}
-
-void GIFImageDecoder::onInitFrameBuffer(size_t frameIndex) {
-  m_currentBufferSawAlpha = false;
-}
-
-bool GIFImageDecoder::canReusePreviousFrameBuffer(size_t frameIndex) const {
-  DCHECK(frameIndex < m_frameBufferCache.size());
-  return m_frameBufferCache[frameIndex].getDisposalMethod() !=
-         ImageFrame::DisposeOverwritePrevious;
+  }
+
+  if (!postDecodeProcessing(index)) {
+    return;
+  }
+}
+
+bool GIFImageDecoder::canReusePreviousFrameBuffer(size_t index) const {
+  DCHECK(index < m_frameBufferCache.size());
+
+  // If the current frame and the next frame depend on the same frame, we cannot
+  // reuse the old frame. We must preserve it for the next frame.
+  //
+  // However, if the current and next frame depend on different frames then we
+  // know the current frame is the last one to use the frame it depends on. That
+  // means the current frame can reuse the previous frame buffer.
+  //
+  // If we do not have information about the next frame yet, we cannot assume it
+  // is safe to reuse the previous frame buffer.
+
+  if (index + 1 >= m_frameBufferCache.size()) {
+    return false;
+  }
+
+  const ImageFrame& frame = m_frameBufferCache[index];
+  size_t requiredFrameIndex = frame.requiredPreviousFrameIndex();
+
+  const ImageFrame& nextFrame = m_frameBufferCache[index + 1];
+  size_t nextRequiredFrameIndex = nextFrame.requiredPreviousFrameIndex();
+
+  return requiredFrameIndex != nextRequiredFrameIndex;
 }
 
 }  // namespace blink