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 <limits>
+#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),
+      m_frameInfos() {}
+
+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 (!data) {
+    if (m_segmentStream)
+      m_segmentStream->setReader(nullptr, false);
+    return;
+  }
+
+  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) {
+    SkCodec* codec = SkCodec::NewFromStream(m_segmentStream);
+    if (codec) {
+      m_codec.reset(codec);
+    } else {
+      // 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;
+      return;
+    }
+
+    // SkCodec::NewFromStream will read enough of the image to get the image
+    // size.
+    SkImageInfo imageInfo = m_codec->getInfo();
+    setSize(imageInfo.width(), imageInfo.height());
+  }
 }
 
 int GIFImageDecoder::repetitionCount() const {
+  if (!m_codec)
+    return cAnimationLoopOnce;
+
   // 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.
+
+  if (isAllDataReceived() && m_frameInfos.size() == 1)
+    return cAnimationNone;
+  if (failed())
+    return cAnimationLoopOnce;
+
+  int repetitionCount = m_codec->getRepetitionCount();
+  switch (repetitionCount) {
+    case 0:
+      return cAnimationLoopOnce;
+    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;
+
+  if (m_frameInfos.size() <= index)
+    return false;
+
+  return m_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 (index < m_frameBufferCache.size())
+    return m_frameBufferCache[index].duration();
+  return 0;
+}
+
+size_t GIFImageDecoder::decodeFrameCount() {
+  if (!m_codec)
+    return 0;
+
+  if (!failed() && !(m_segmentStream && m_segmentStream->isCleared()))
+    m_frameInfos = m_codec->getFrameInfo();
+
+  return m_frameInfos.size();
+}
+
+void GIFImageDecoder::initializeNewFrame(size_t index) {
+  DCHECK(m_codec);
+
+  ImageFrame& frame = m_frameBufferCache[index];
+  // SkCodec does not inform us if only a portion of the image was updated
+  // in the current frame. Because of this, rather than correctly filling in
+  // the frame rect, we set the frame rect to be the image's full size.
+  IntSize fullImageSize = size();
+  frame.setOriginalFrameRect(IntRect(IntPoint(), fullImageSize));
+  frame.setDuration(m_frameInfos[index].fDuration);
+  size_t requiredPreviousFrameIndex = m_frameInfos[index].fRequiredFrame;
+  if (requiredPreviousFrameIndex == SkCodec::kNone)
+    requiredPreviousFrameIndex = WTF::kNotFound;
+  frame.setRequiredPreviousFrameIndex(requiredPreviousFrameIndex);
+  // 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);
+}
+
+void GIFImageDecoder::decode(size_t index) {
+  if (failed())
+    return;
+
+  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);
+
+  SkCodec::Options options;
+  options.fFrameIndex = index;
+  options.fHasPriorFrame = false;
+  options.fZeroInitialized = true;
+
+  ImageFrame& frame = m_frameBufferCache[index];
+  if (frame.getStatus() == ImageFrame::FrameEmpty) {
+    size_t requiredPreviousFrameIndex = frame.requiredPreviousFrameIndex();
+    if (requiredPreviousFrameIndex == WTF::kNotFound) {
+      frame.allocatePixelData(size().width(), size().height(),
+                              colorSpaceForSkImages());
+      frame.zeroFillPixelData();

[cblume, 2017/03/25 07:54:39]

I added the zero initialization here.


Previously, I wasn't setting options.fZeroInitialized. Nor was I zeroing the
pixel data (after landing a patch that no longer calls zeroFillPixelData()
inside allocatePixelData() ).

This caused errors. But I'm surprised by that.
The default should be for SkCodec to zero fill. So even if I didn't zero-fill,
SkCodec should have. Right? But the errors feel like that wasn't happening.


Additionally, I may want to lie about the zero initialization. If I claim it was
zero filled then SkCodec won't zero fill. When I learn how many rows were
decoded, I zero-fill the rest. Right? So I think I want to lie here (and include
a comment explaining that)

[scroggo_chromium, 2017/04/05 18:06:14]

Right.
If that is the case, it is a bug in SkCodec.
No, that would cause a problem.

Setting it to kYes_ZeroInitialized means that SkCodec can skip zeroing the
memory. If an image frame is subset (and independent), SkCodec won't zero it,
but then will draw the frame on top of it. So you would need to follow up by
zeroing the pixels that were not touched by the frame.

What you really want is for SkCodec to not zero the rows that it didn't decode.
It does not, even if you use kNo_ZeroInitialized. That allows you to follow up
and zero-fill the rest. (There are a couple exceptions (e.g. subset frame) where
SkCodec goes ahead and fills the entire image rectangle, and then reports via
rowsDecoded that all were initialized.)

[cblume, 2017/04/08 01:19:20]

This was a false alarm on my part. The errors were separate I believe.
Oh. Perfect. So this is actually working exactly like we want right now. Goodie
:D

+    } else {
+      ImageFrame& requiredPreviousFrame =
+          m_frameBufferCache[requiredPreviousFrameIndex];
+
+      if (requiredPreviousFrame.getStatus() != ImageFrame::FrameComplete)
+        decode(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;
       }
+
+      options.fHasPriorFrame = true;
     }
-  } else {
-    for (; rowBegin != rowEnd; ++rowBegin, ++currentAddress) {
-      const size_t sourceValue = *rowBegin;
-      if ((sourceValue != transparentPixel) &&
-          (sourceValue < colorTable.size()))
-        *currentAddress = colorTableIter[sourceValue];
-      else
-        m_currentBufferSawAlpha = 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;
     }
-  }
-
-  // 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 setFailed();
-
-  if (!m_currentBufferSawAlpha)
-    correctAlphaWhenFrameBufferSawNoAlpha(frameIndex);
-
-  m_frameBufferCache[frameIndex].setStatus(ImageFrame::FrameComplete);
-
-  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)) {
+    frame.setStatus(ImageFrame::FramePartial);
+  }
+
+  int rowsDecoded = 0;
+  SkCodec::Result incrementalDecodeResult =
+      m_codec->incrementalDecode(&rowsDecoded);
+  switch (incrementalDecodeResult) {
+    case SkCodec::kSuccess:
+      frame.setPixelsChanged(true);
+      frame.setStatus(ImageFrame::FrameComplete);
+      postDecodeProcessing(index);
+      break;
+    case SkCodec::kIncompleteInput:
+      if (frameIsCompleteAtIndex(index) || isAllDataReceived()) {
+        setFailed();
+        return;
+      }
+
+      {
+        IntRect remainingRect = frame.originalFrameRect();
+        remainingRect.setY(rowsDecoded);
+        remainingRect.setHeight(remainingRect.height() - rowsDecoded);
+        frame.zeroFillFrameRect(remainingRect);
+      }
+
+      frame.setPixelsChanged(true);
+      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;
+  }
+}
+
+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