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 <limits>
-#include "platform/image-decoders/gif/GIFImageReader.h"
 #include "platform/wtf/NotFound.h"
 #include "platform/wtf/PtrUtil.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
 
 namespace blink {
 
 GIFImageDecoder::GIFImageDecoder(AlphaOption alpha_option,
                                  const ColorBehavior& color_behavior,
                                  size_t max_decoded_bytes)
     : ImageDecoder(alpha_option, color_behavior, max_decoded_bytes),
-      repetition_count_(kAnimationLoopOnce) {}
-
-GIFImageDecoder::~GIFImageDecoder() {}
+      codec_(),
+      segment_stream_(nullptr) {}
+
+GIFImageDecoder::~GIFImageDecoder() {
+  if (!codec_) {
+    // if we did not create |codec_| and thus did not pass ownership to it
+    if (segment_stream_)
+      delete segment_stream_;
+  }
+}
 
 void GIFImageDecoder::OnSetData(SegmentReader* data) {
-  if (reader_)
-    reader_->SetData(data);
+  if (!data) {
+    if (segment_stream_)
+      segment_stream_->SetReader(nullptr);
+    return;
+  }
+
+  if (!segment_stream_)
+    segment_stream_ = new SegmentStream();
+
+  segment_stream_->SetReader(PassRefPtr<SegmentReader>(data));
+
+  if (!codec_) {
+    codec_.reset(SkCodec::NewFromStream(segment_stream_, nullptr));
+    if (!codec_) {
+      // |segment_stream_|'s ownership is passed into NewFromStream.
+      // It is deleted if NewFromStream fails.
+      // If NewFromStream fails, we set |segment_stream_| to null so
+      // we aren't pointing to reclaimed memory.
+      segment_stream_ = nullptr;
+      return;
+    }
+
+    // SkCodec::NewFromStream will read enough of the image to get the image
+    // size.
+    SkImageInfo image_info = codec_->getInfo();
+    SetSize(image_info.width(), image_info.height());
+  }
 }
 
 int GIFImageDecoder::RepetitionCount() const {
+  if (!codec_)
+    return kAnimationLoopOnce;
+
+  DCHECK(!Failed());
+
   // 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 kCLoopCountNotSeen, in which case we
-  // should default to looping once (the initial value for
-  // |repetition_count_|).
+  // 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 kCLoopCountNotSeen, 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
-  // |repetition_count_| 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() && reader_->ImagesCount() == 1)
-    repetition_count_ = kAnimationNone;
-  else if (Failed() || (reader_ && (!reader_->ImagesCount())))
-    repetition_count_ = kAnimationLoopOnce;
-  else if (reader_ && reader_->LoopCount() != kCLoopCountNotSeen)
-    repetition_count_ = reader_->LoopCount();
-  return repetition_count_;
+  // SkCodec will parse forward in the file if the repetition count has not been
+  // seen yet.
+  int repetition_count = codec_->getRepetitionCount();
+
+  switch (repetition_count) {
+    case 0: {
+      size_t frame_count = codec_->getFrameCount();
+      if (IsAllDataReceived() && frame_count == 1)
+        return kAnimationNone;
+
+      return kAnimationLoopOnce;
+    }
+    case SkCodec::kRepetitionCountInfinite:
+      return kAnimationLoopInfinite;
+    default:
+      return repetition_count;
+  }
 }
 
 bool GIFImageDecoder::FrameIsCompleteAtIndex(size_t index) const {
-  return reader_ && (index < reader_->ImagesCount()) &&
-         reader_->FrameContext(index)->IsComplete();
+  if (!codec_)
+    return false;
+
+  if (static_cast<size_t>(codec_->getFrameCount()) <= index)
+    return false;
+
+  SkCodec::FrameInfo frame_info;
+  codec_->getFrameInfo(index, &frame_info);
+  return frame_info.fFullyReceived;
 }
 
 float GIFImageDecoder::FrameDurationAtIndex(size_t index) const {
-  return (reader_ && (index < reader_->ImagesCount()) &&
-          reader_->FrameContext(index)->IsHeaderDefined())
-             ? reader_->FrameContext(index)->DelayTime()
-             : 0;
+  if (index < frame_buffer_cache_.size())
+    return frame_buffer_cache_[index].Duration();
+  return 0;
 }
 
 bool GIFImageDecoder::SetFailed() {
-  reader_.reset();
+  DCHECK(codec_);
+
+  segment_stream_ = nullptr;
+  codec_ = nullptr;
   return ImageDecoder::SetFailed();
 }
 
-bool GIFImageDecoder::HaveDecodedRow(size_t frame_index,
-                                     GIFRow::const_iterator row_begin,
-                                     size_t width,
-                                     size_t row_number,
-                                     unsigned repeat_count,
-                                     bool write_transparent_pixels) {
-  const GIFFrameContext* frame_context = reader_->FrameContext(frame_index);
-  // The pixel data and coordinates supplied to us are relative to the frame's
-  // origin within the entire image size, i.e.
-  // (frameC_context->xOffset, frame_context->yOffset). There is no guarantee
-  // that width == (size().width() - frame_context->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 x_begin = frame_context->XOffset();
-  const int y_begin = frame_context->YOffset() + row_number;
-  const int x_end = std::min(static_cast<int>(frame_context->XOffset() + width),
-                             Size().Width());
-  const int y_end = std::min(
-      static_cast<int>(frame_context->YOffset() + row_number + repeat_count),
-      Size().Height());
-  if (!width || (x_begin < 0) || (y_begin < 0) || (x_end <= x_begin) ||
-      (y_end <= y_begin))
-    return true;
-
-  const GIFColorMap::Table& color_table =
-      frame_context->LocalColorMap().IsDefined()
-          ? frame_context->LocalColorMap().GetTable()
-          : reader_->GlobalColorMap().GetTable();
-
-  if (color_table.IsEmpty())
-    return true;
-
-  GIFColorMap::Table::const_iterator color_table_iter = color_table.begin();
-
-  // Initialize the frame if necessary.
-  ImageFrame& buffer = frame_buffer_cache_[frame_index];
-  if (!InitFrameBuffer(frame_index))
-    return false;
-
-  const size_t transparent_pixel = frame_context->TransparentPixel();
-  GIFRow::const_iterator row_end = row_begin + (x_end - x_begin);
-  ImageFrame::PixelData* current_address = buffer.GetAddr(x_begin, y_begin);
-
-  // 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 |write_transparent_pixels|.
-  // 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 (write_transparent_pixels) {
-    for (; row_begin != row_end; ++row_begin, ++current_address) {
-      const size_t source_value = *row_begin;
-      if ((source_value != transparent_pixel) &&
-          (source_value < color_table.size())) {
-        *current_address = color_table_iter[source_value];
-      } else {
-        *current_address = 0;
-        current_buffer_saw_alpha_ = true;
-      }
-    }
+size_t GIFImageDecoder::DecodeFrameCount() {
+  if (!codec_)
+    return 0;
+
+  if (Failed() || segment_stream_->IsCleared())
+    return 0;
+
+  return codec_->getFrameCount();
+}
+
+void GIFImageDecoder::InitializeNewFrame(size_t index) {
+  DCHECK(codec_);
+
+  ImageFrame& frame = frame_buffer_cache_[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.
+  // The original frame rect is not used, anyway.
+  IntSize full_image_size = Size();
+  frame.SetOriginalFrameRect(IntRect(IntPoint(), full_image_size));
+
+  SkCodec::FrameInfo frame_info;
+  codec_->getFrameInfo(index, &frame_info);
+  frame.SetDuration(frame_info.fDuration);
+  frame.SetHasAlpha(!SkAlphaTypeIsOpaque(frame_info.fAlphaType));
+  size_t required_previous_frame_index;
+  if (frame_info.fRequiredFrame == SkCodec::kNone) {
+    required_previous_frame_index = WTF::kNotFound;
   } else {
-    for (; row_begin != row_end; ++row_begin, ++current_address) {
-      const size_t source_value = *row_begin;
-      if ((source_value != transparent_pixel) &&
-          (source_value < color_table.size()))
-        *current_address = color_table_iter[source_value];
-      else
-        current_buffer_saw_alpha_ = true;
-    }
-  }
-
-  // Tell the frame to copy the row data if need be.
-  if (repeat_count > 1)
-    buffer.CopyRowNTimes(x_begin, x_end, y_begin, y_end);
-
-  buffer.SetPixelsChanged(true);
-  return true;
-}
-
-bool GIFImageDecoder::ParseCompleted() const {
-  return reader_ && reader_->ParseCompleted();
-}
-
-bool GIFImageDecoder::FrameComplete(size_t frame_index) {
-  // Initialize the frame if necessary.  Some GIFs insert do-nothing frames,
-  // in which case we never reach HaveDecodedRow() before getting here.
-  if (!InitFrameBuffer(frame_index))
-    return SetFailed();
-
-  if (!current_buffer_saw_alpha_)
-    CorrectAlphaWhenFrameBufferSawNoAlpha(frame_index);
-
-  frame_buffer_cache_[frame_index].SetStatus(ImageFrame::kFrameComplete);
-
-  return true;
-}
-
-void GIFImageDecoder::ClearFrameBuffer(size_t frame_index) {
-  if (reader_ && frame_buffer_cache_[frame_index].GetStatus() ==
-                     ImageFrame::kFramePartial) {
-    // Reset the state of the partial frame in the reader so that the frame
-    // can be decoded again when requested.
-    reader_->ClearDecodeState(frame_index);
-  }
-  ImageDecoder::ClearFrameBuffer(frame_index);
-}
-
-size_t GIFImageDecoder::DecodeFrameCount() {
-  Parse(kGIFFrameCountQuery);
-  // If decoding fails, |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() ? frame_buffer_cache_.size() : reader_->ImagesCount();
-}
-
-void GIFImageDecoder::InitializeNewFrame(size_t index) {
-  ImageFrame* buffer = &frame_buffer_cache_[index];
-  const GIFFrameContext* frame_context = reader_->FrameContext(index);
-  buffer->SetOriginalFrameRect(
-      Intersection(frame_context->FrameRect(), IntRect(IntPoint(), Size())));
-  buffer->SetDuration(frame_context->DelayTime());
-  buffer->SetDisposalMethod(frame_context->GetDisposalMethod());
-  buffer->SetRequiredPreviousFrameIndex(
-      FindRequiredPreviousFrame(index, false));
+    required_previous_frame_index =
+        static_cast<size_t>(frame_info.fRequiredFrame);
+  }
+  frame.SetRequiredPreviousFrameIndex(required_previous_frame_index);
+
+  ImageFrame::DisposalMethod disposal_method = ImageFrame::kDisposeNotSpecified;
+  switch (frame_info.fDisposalMethod) {
+    case SkCodecAnimation::DisposalMethod::kKeep:
+      disposal_method = ImageFrame::kDisposeKeep;
+      break;
+    case SkCodecAnimation::DisposalMethod::kRestoreBGColor:
+      disposal_method = ImageFrame::kDisposeOverwriteBgcolor;
+      break;
+    case SkCodecAnimation::DisposalMethod::kRestorePrevious:
+      disposal_method = ImageFrame::kDisposeOverwritePrevious;
+      break;
+  }
+  frame.SetDisposalMethod(disposal_method);
 }
 
 void GIFImageDecoder::Decode(size_t index) {
-  Parse(kGIFFrameCountQuery);
-
-  if (Failed())
+  if (!codec_)
     return;
 
+  DCHECK(!Failed());
+
+  DCHECK_LT(index, frame_buffer_cache_.size());
+
+  if (segment_stream_->IsCleared())
+    return;
+
   UpdateAggressivePurging(index);
-
-  Vector<size_t> frames_to_decode = FindFramesToDecode(index);
-  for (auto i = frames_to_decode.rbegin(); i != frames_to_decode.rend(); ++i) {
-    if (!reader_->Decode(*i)) {
+  SkImageInfo image_info = codec_->getInfo()
+                               .makeColorType(kN32_SkColorType)
+                               .makeColorSpace(ColorSpaceForSkImages());
+
+  SkCodec::Options options;
+  options.fFrameIndex = index;
+  options.fPriorFrame = SkCodec::kNone;
+  options.fZeroInitialized = SkCodec::kNo_ZeroInitialized;
+
+  ImageFrame& frame = frame_buffer_cache_[index];
+  if (frame.GetStatus() == ImageFrame::kFrameEmpty) {
+    size_t required_previous_frame_index = frame.RequiredPreviousFrameIndex();
+    if (required_previous_frame_index == WTF::kNotFound) {
+      frame.AllocatePixelData(Size().Width(), Size().Height(),
+                              ColorSpaceForSkImages());
+    } else {
+      // Any frame in the range [required_previous_frame_index, index) which
+      // has a disposal method other than kRestorePrevious can be provided as
+      // the prior frame to SkCodec.
+      //
+      // This is because SkCodec sets SkCodec::FrameInfo::fRequiredFrame to the
+      // earliest frame which can be used. This might come up when several
+      // frames update the same subregion. If that same subregion is about to be
+      // overwritten, it doesn't matter which frame in that chain is provided.
+      size_t previous_frame_index = required_previous_frame_index;
+      for (size_t i = required_previous_frame_index; i < index; i++) {

[scroggo_chromium, 2017/07/10 17:45:57]

Should we search backwards, given that we most likely decoded the prior frame
before this one?

[cblume, 2017/07/11 00:23:37]

I was thinking about exactly this, actually. And I'm quite torn on a number of
reasons (when we fix the caching, thing will change...and with contiguous memory
& linear searches & prefetching & a small list, it is unlikely our measurement
tools will even detect anything).

Since I am torn, I'm happy to search backwards.

But the frame we keep in Blink isn't the previous frame. It is the frame marked
as the required frame. SkCodec marks the earliest frame, which means a forward
search is most likely to hit it first.

[scroggo_chromium, 2017/07/11 17:41:28]

Ah, good point.

+        ImageFrame& previous_frame = frame_buffer_cache_[i];
+
+        if (previous_frame.GetDisposalMethod() ==
+            ImageFrame::kDisposeOverwritePrevious)
+          break;

[scroggo_chromium, 2017/07/10 17:45:57]

I think you want this to be continue, so that we'll skip over this one. It
cannot be used as the prior frame, but another one could.

[cblume, 2017/07/11 00:23:37]

Done.

+
+        if (previous_frame.GetStatus() == ImageFrame::kFrameComplete) {
+          previous_frame_index = i;
+          break;
+        }
+      }
+
+      ImageFrame& previous_frame = frame_buffer_cache_[previous_frame_index];
+      if (previous_frame.GetStatus() != ImageFrame::kFrameComplete)
+        Decode(previous_frame_index);
+
+      // We try to reuse |previous_frame| as starting state to avoid copying.
+      // If CanReusePreviousFrameBuffer returns false, we must copy the data
+      // since |previous_frame| is necessary to decode this or later frames.
+      // In that case copy the data instead.
+      if ((!CanReusePreviousFrameBuffer(index) ||
+           !frame.TakeBitmapDataIfWritable(&previous_frame)) &&
+          !frame.CopyBitmapData(previous_frame)) {
+        SetFailed();
+        return;
+      }
+      options.fPriorFrame = previous_frame_index;
+    }
+  }
+
+  if (frame.GetStatus() == ImageFrame::kFrameAllocated) {
+    SkCodec::Result start_incremental_decode_result =
+        codec_->startIncrementalDecode(image_info, frame.Bitmap().getPixels(),
+                                       frame.Bitmap().rowBytes(), &options,
+                                       nullptr, nullptr);
+    switch (start_incremental_decode_result) {
+      case SkCodec::kSuccess:
+        break;
+      case SkCodec::kIncompleteInput:
+        return;
+      case SkCodec::kErrorInInput:
+        frame.ZeroFillPixelData();
+        frame.SetPixelsChanged(true);
+      // Fall through
+      default:
+        SetFailed();
+        return;
+    }
+    frame.SetStatus(ImageFrame::kFramePartial);
+  }
+  int rows_decoded = 0;
+  bool error_in_input = false;
+  SkCodec::Result incremental_decode_result =
+      codec_->incrementalDecode(&rows_decoded);
+  switch (incremental_decode_result) {
+    case SkCodec::kSuccess:
+      frame.SetPixelsChanged(true);
+      frame.SetStatus(ImageFrame::kFrameComplete);
+      PostDecodeProcessing(index);
+      break;
+    case SkCodec::kErrorInInput:
+      error_in_input = true;
+    // Fall through
+    case SkCodec::kIncompleteInput:
+      if (!index) {
+        bool oldAlpha = frame.HasAlpha();
+
+        IntRect remaining_rect = IntRect(IntPoint(), Size());
+        remaining_rect.SetY(rows_decoded);
+        remaining_rect.SetHeight(remaining_rect.Height() - rows_decoded);
+        frame.ZeroFillFrameRect(remaining_rect);
+        // ZeroFillFrameRect() resets the alpha to true.
+        // We want to preserve the alpha. So we need to set it back.
+        frame.SetHasAlpha(oldAlpha);
+      }
+
+      frame.SetPixelsChanged(true);
+
+      if (FrameIsCompleteAtIndex(index) || IsAllDataReceived() ||
+          error_in_input) {
+        SetFailed();
+        return;
+      }
+
+      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 >= frame_buffer_cache_.size() - 1 && IsAllDataReceived() &&
-      reader_ && !reader_->ParseCompleted())
-    SetFailed();
-}
-
-void GIFImageDecoder::Parse(GIFParseQuery query) {
-  if (Failed())
-    return;
-
-  if (!reader_) {
-    reader_ = WTF::MakeUnique<GIFImageReader>(this);
-    reader_->SetData(data_);
-  }
-
-  if (!reader_->Parse(query))
-    SetFailed();
-}
-
-void GIFImageDecoder::OnInitFrameBuffer(size_t frame_index) {
-  current_buffer_saw_alpha_ = false;
-}
-
-bool GIFImageDecoder::CanReusePreviousFrameBuffer(size_t frame_index) const {
-  DCHECK(frame_index < frame_buffer_cache_.size());
-  return frame_buffer_cache_[frame_index].GetDisposalMethod() !=
+  }
+}
+
+bool GIFImageDecoder::CanReusePreviousFrameBuffer(size_t index) const {
+  DCHECK(index < frame_buffer_cache_.size());
+  return frame_buffer_cache_[index].GetDisposalMethod() !=
          ImageFrame::kDisposeOverwritePrevious;
 }
 
 }  // namespace blink