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The Tor Browser
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nsWebPDecoder.h (3090B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
      2 *
      3 * This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef mozilla_image_decoders_nsWebPDecoder_h
      8 #define mozilla_image_decoders_nsWebPDecoder_h
      9 
     10 #include "Decoder.h"
     11 #include "webp/demux.h"
     12 #include "StreamingLexer.h"
     13 #include "SurfacePipe.h"
     14 
     15 namespace mozilla {
     16 namespace image {
     17 class RasterImage;
     18 
     19 class nsWebPDecoder final : public Decoder {
     20 public:
     21  virtual ~nsWebPDecoder();
     22 
     23  DecoderType GetType() const override { return DecoderType::WEBP; }
     24 
     25 protected:
     26  LexerResult DoDecode(SourceBufferIterator& aIterator,
     27                       IResumable* aOnResume) override;
     28  Maybe<glean::impl::MemoryDistributionMetric> SpeedMetric() const override;
     29 
     30 private:
     31  friend class DecoderFactory;
     32 
     33  // Decoders should only be instantiated via DecoderFactory.
     34  explicit nsWebPDecoder(RasterImage* aImage);
     35 
     36  void ApplyColorProfile(const char* aProfile, size_t aLength);
     37 
     38  LexerResult UpdateBuffer(SourceBufferIterator& aIterator,
     39                           SourceBufferIterator::State aState);
     40  LexerResult ReadData();
     41  LexerResult ReadHeader(WebPDemuxer* aDemuxer, bool aIsComplete);
     42  LexerResult ReadPayload(WebPDemuxer* aDemuxer, bool aIsComplete);
     43 
     44  nsresult CreateFrame(const OrientedIntRect& aFrameRect);
     45  void EndFrame();
     46 
     47  LexerResult ReadSingle(const uint8_t* aData, size_t aLength,
     48                         const OrientedIntRect& aFrameRect);
     49 
     50  LexerResult ReadMultiple(WebPDemuxer* aDemuxer, bool aIsComplete);
     51 
     52  /// The SurfacePipe used to write to the output surface.
     53  SurfacePipe mPipe;
     54 
     55  /// The buffer used to accumulate data until the complete WebP header is
     56  /// received, if and only if the iterator is discontiguous.
     57  Vector<uint8_t> mBufferedData;
     58 
     59  /// The libwebp output buffer descriptor pointing to the decoded data.
     60  WebPDecBuffer mBuffer;
     61 
     62  /// The libwebp incremental decoder descriptor, wraps mBuffer.
     63  WebPIDecoder* mDecoder;
     64 
     65  /// Blend method for the current frame.
     66  BlendMethod mBlend;
     67 
     68  /// Disposal method for the current frame.
     69  DisposalMethod mDisposal;
     70 
     71  /// Frame timeout for the current frame;
     72  FrameTimeout mTimeout;
     73 
     74  /// Surface format for the current frame.
     75  gfx::SurfaceFormat mFormat;
     76 
     77  /// Frame rect for the current frame.
     78  OrientedIntRect mFrameRect;
     79 
     80  /// The last row of decoded pixels written to mPipe.
     81  int mLastRow;
     82 
     83  /// Number of decoded frames.
     84  uint32_t mCurrentFrame;
     85 
     86  /// Pointer to the start of the contiguous encoded image data.
     87  const uint8_t* mData;
     88 
     89  /// Length of data pointed to by mData.
     90  size_t mLength;
     91 
     92  /// True if the iterator has reached its end.
     93  bool mIteratorComplete;
     94 
     95  /// True if this decoding pass requires a WebPDemuxer.
     96  bool mNeedDemuxer;
     97 
     98  /// True if we have setup the color profile for the image.
     99  bool mGotColorProfile;
    100 };
    101 
    102 }  // namespace image
    103 }  // namespace mozilla
    104 
    105 #endif  // mozilla_image_decoders_nsWebPDecoder_h