Add VideoPacket struct for video packets. Refactor Decode interface to use it.

remoting/base/decoder.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_BASE_DECODER_H_
 #define REMOTING_BASE_DECODER_H_
 
+#include <vector>
+
 #include "base/task.h"
 #include "base/scoped_ptr.h"
 #include "gfx/rect.h"
 #include "media/base/video_frame.h"
 #include "remoting/proto/video.pb.h"
 
 namespace remoting {
 
 typedef std::vector<gfx::Rect> UpdatedRects;
 
 // Interface for a decoder that takes a stream of bytes from the network and
 // outputs frames of data.
 //
 // TODO(ajwong): Beef up this documentation once the API stablizes.
 class Decoder {
  public:
+  // DecodeResult is returned from DecodePacket() and indicates current state
+  // of the decoder. DECODE_DONE means that last packet for the frame was
+  // processed, and the frame can be displayed now. DECODE_IN_PROGRESS
+  // indicates that the decoder must receive more data before the frame can be
+  // displayed. DECODE_ERROR is returned if there was an error in the stream.
+  enum DecodeResult {
+    DECODE_ERROR = -1,
+    DECODE_IN_PROGRESS,
+    DECODE_DONE,
+  };
+
   Decoder() {}
   virtual ~Decoder() {}
 
-  // TODO(ajwong): This API is incorrect in the face of a streaming decode
-  // protocol like VP8.  However, it breaks the layering abstraction by
-  // depending on the network packet protocol buffer type. I'm going to go
-  // forward with it as is, and then refactor again to support streaming
-  // decodes.
-
   // Initializes the decoder to draw into the given |frame|.  The |clip|
   // specifies the region to draw into.  The clip region must fit inside
-  // the dimensions of frame. Failure to do so will CHECK Fail.
-  //
-  // TODO(ajwong): Should this take the source pixel format?
-  // TODO(ajwong): Should the protocol be split into basic-types followed
-  //   by packet types?  Basic types might include the format enum below.
-  virtual void Initialize(scoped_refptr<media::VideoFrame> frame,
-                          const gfx::Rect& clip, int bytes_per_src_pixel) = 0;
+  // the dimensions of frame. Failure to do so will CHECK fail.
+  virtual void Initialize(scoped_refptr<media::VideoFrame> frame) = 0;
+
+  // Feeds more data into the decoder.
+  virtual DecodeResult DecodePacket(const VideoPacket* packet) = 0;
+
+  // Returns rects that were updated in the last frame. Can be called only
+  // after DecodePacket returned DECODE_DONE. Caller keeps ownership of
+  // |rects|. |rects| is kept empty if whole screen needs to be updated.
+  virtual void GetUpdatedRects(UpdatedRects* rects) = 0;
 
   // Reset the decoder to an uninitialized state. Release all references to
   // the initialized |frame|.  Initialize() must be called before the decoder
   // is used again.
   virtual void Reset() = 0;
 
-  // Feeds more data into the decoder.
-  virtual void DecodeBytes(const std::string& encoded_bytes) = 0;
-
-  // Returns true if decoder is ready to accept data via ProcessRectangleData.
+  // Returns true if decoder is ready to accept data via DecodePacket.
   virtual bool IsReadyForData() = 0;
 
   virtual VideoPacketFormat::Encoding Encoding() = 0;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_BASE_DECODER_H_