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.
  *
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  * 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.
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  *    notice, this list of conditions and the following disclaimer in the
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  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 #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 {
   // 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();

[scroggo_chromium, 2016/12/19 14:28:54]

It looks like you removed a line that says

  CHECK(m_codec);

Is it no longer the case that we're guaranteed to have an m_codec? If not, we
need to check for null.

(Same for other cases)

[cblume, 2016/12/20 21:59:00]

Done.

+  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();
+  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];
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+  if (frameInfos.size() <= index) {
+    return 0;
+  }
+
+  return frameInfos[index].fDuration;
+}
+
+void GIFImageDecoder::decodeSize() {
+  SkImageInfo imageInfo = m_codec->getInfo();
+  setSize(imageInfo.width(), imageInfo.height());
+}
+
+size_t GIFImageDecoder::decodeFrameCount() {
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+  return frameInfos.size();
+}
+
+void GIFImageDecoder::initializeNewFrame(size_t index) {
+  ImageFrame& frame = m_frameBufferCache[index];
+  std::vector<SkCodec::FrameInfo> frameInfos = m_codec->getFrameInfo();
+
+  IntSize frameSize = size();

[scroggo_chromium, 2016/12/19 14:28:54]

Maybe a FIXME here that we need to verify that we either do not need this
information, or SkCodec needs to give it to us?

[cblume, 2016/12/20 21:59:00]

Done.

+  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_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);
+
+  SkCodec::Options options;
+  options.fFrameIndex = index;
+  options.fHasPriorFrame = false;
+
+  ImageFrame& frame = m_frameBufferCache[index];
+  if (frame.getStatus() == ImageFrame::FrameEmpty) {
+    size_t requiredPreviousFrameIndex = frame.requiredPreviousFrameIndex();
+    if (requiredPreviousFrameIndex != WTF::kNotFound) {
+      options.fHasPriorFrame = true;
+    }
+
+    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];
+
+      if (canReusePreviousFrameBuffer(index)) {
+        if (!frame.takeBitmapDataIfWritable(&requiredPreviousFrame)) {
+          setFailed();

[scroggo_chromium, 2016/12/19 14:28:54]

This isn't quite right. Look at where these methods are currently called [1]. If
we cannot takeBitmapDataData, we need to copy it.

[1]
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/image...

[cblume, 2016/12/20 21:59:00]

Done.

+          return;
+        }
       } else {
-        *currentAddress = 0;
-        m_currentBufferSawAlpha = true;
+        if (!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())
+  }
+
+  if (!postDecodeProcessing(index)) {
     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());
+  // TODO Without knowing the disposal method of a frame (which you see copied
+  // below from the old GIFImageDecoder), I would need to rebuild frame
+  // dependencies.
+  //
+  // One option after we loop once and determine if a frame is referenced by a
+  // later frame. The goal here is to not reuse a buffer that will be needed
+  // again later.

[cblume, 2016/12/19 08:04:03]

Ideally, we would only take (reuse) the bitmap on the last frame that references
that particular required frame.
But I only know that after making the first loop through the animation.

I can build up this information, but I want to confirm this is the behavior we
want.

We cannot reuse a bitmap on the first animation loop. And on the second loop,
1.) we will have already allocated all the bitmaps, or
2.) we were purging as we went anyway (current behavior)

[scroggo_chromium, 2016/12/19 14:28:54]

No, I do not think that's the behavior that we want. We can check the next
frame's fRequiredFrame if it has been (partially) received. If it is a
common/problematic case where the next frame has not been partially received, we
should update SkCodec's API to give more info.

That said, if we do not know whether there is another frame after this one
(which is the case if we haven't read its header) we also do not know whether
any frames depend on this one.

   return m_frameBufferCache[frameIndex].getDisposalMethod() !=
          ImageFrame::DisposeOverwritePrevious;
 }
 
 }  // namespace blink