Implement WebP image decoder.

1 files changed, 91 insertions, 0 deletions

diff --git a/image/decoders/nsWebPDecoder.h b/image/decoders/nsWebPDecoder.h
new file mode 100644
index 000000000..5b3951cfc
--- /dev/null
+++ b/image/decoders/nsWebPDecoder.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_image_decoders_nsWebPDecoder_h
+#define mozilla_image_decoders_nsWebPDecoder_h
+
+#include "Decoder.h"
+#include "webp/demux.h"
+#include "StreamingLexer.h"
+#include "SurfacePipe.h"
+
+namespace mozilla {
+namespace image {
+class RasterImage;
+
+class nsWebPDecoder : public Decoder
+{
+public:
+  virtual ~nsWebPDecoder();
+
+protected:
+  LexerResult DoDecode(SourceBufferIterator& aIterator,
+                       IResumable* aOnResume) override;
+
+private:
+  friend class DecoderFactory;
+
+  // Decoders should only be instantiated via DecoderFactory.
+  explicit nsWebPDecoder(RasterImage* aImage);
+
+  enum class State
+  {
+    WEBP_DATA,
+    FINISHED_WEBP_DATA
+  };
+
+  LexerTransition<State> ReadHeader(const char* aData, size_t aLength);
+  LexerTransition<State> ReadPayload(const char* aData, size_t aLength);
+  LexerTransition<State> FinishedData();
+
+  nsresult CreateFrame(const nsIntRect& aFrameRect);
+  void EndFrame();
+
+  nsresult GetDataBuffer(const uint8_t*& aData, size_t& aLength);
+  nsresult SaveDataBuffer(const uint8_t* aData, size_t aLength);
+
+  LexerTransition<State> ReadSingle(const uint8_t* aData, size_t aLength,
+                                    bool aAppend, const IntRect& aFrameRect);
+
+  LexerTransition<State> ReadMultiple(const uint8_t* aData, size_t aLength);
+
+  StreamingLexer<State> mLexer;
+
+  /// The SurfacePipe used to write to the output surface.
+  SurfacePipe mPipe;
+
+  /// The buffer used to accumulate data until the complete WebP header is received.
+  Vector<uint8_t> mData;
+
+  /// The libwebp output buffer descriptor pointing to the decoded data.
+  WebPDecBuffer mBuffer;
+
+  /// The libwebp incremental decoder descriptor, wraps mBuffer.
+  WebPIDecoder* mDecoder;
+
+  /// Blend method for the current frame.
+  BlendMethod mBlend;
+
+  /// Disposal method for the current frame.
+  DisposalMethod mDisposal;
+
+  /// Frame timeout for the current frame;
+  FrameTimeout mTimeout;
+
+  /// Surface format for the current frame.
+  gfx::SurfaceFormat mFormat;
+
+  /// The last row of decoded pixels written to mPipe.
+  int mLastRow;
+
+  /// Number of decoded frames.
+  uint32_t mCurrentFrame;
+};
+
+} // namespace image
+} // namespace mozilla
+
+#endif // mozilla_image_decoders_nsWebPDecoder_h