Allow multiple concurrent Decode() requests in VideoDecoder interface.

media/filters/fake_video_decoder.h

 // Copyright 2013 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 MEDIA_FILTERS_FAKE_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_FAKE_VIDEO_DECODER_H_
 
 #include <list>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/memory/weak_ptr.h"
+#include "base/threading/thread_checker.h"
 #include "media/base/callback_holder.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/video_decoder.h"
 #include "media/base/video_decoder_config.h"
 #include "media/base/video_frame.h"
 #include "ui/gfx/size.h"
 
 using base::ResetAndReturn;
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 
 class FakeVideoDecoder : public VideoDecoder {
  public:
   // Constructs an object with a decoding delay of |decoding_delay| frames.
-  FakeVideoDecoder(int decoding_delay, bool supports_get_decode_output);
+  FakeVideoDecoder(int decoding_delay,
+                   bool supports_get_decode_output,
+                   int max_parallel_decoding_requests);
   virtual ~FakeVideoDecoder();
 
   // VideoDecoder implementation.
   virtual void Initialize(const VideoDecoderConfig& config,
                           const PipelineStatusCB& status_cb) OVERRIDE;
   virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
                       const DecodeCB& decode_cb) OVERRIDE;
   virtual void Reset(const base::Closure& closure) OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual scoped_refptr<VideoFrame> GetDecodeOutput() OVERRIDE;
+  virtual int GetMaxDecodeRequests() const OVERRIDE;
 
   // Holds the next init/decode/reset callback from firing.
   void HoldNextInit();
-  void HoldNextDecode();
+  void HoldDecode();
   void HoldNextReset();
 
   // Satisfies the pending init/decode/reset callback, which must be ready to
   // fire when these methods are called.
   void SatisfyInit();
   void SatisfyDecode();
   void SatisfyReset();
 
+  // Satisfies single  decode request.
+  void SatisfySingleDecode();
+
+  void SimulateError();
+
   int total_bytes_decoded() const { return total_bytes_decoded_; }
 
  private:
   enum State {
     UNINITIALIZED,
-    NORMAL
+    NORMAL,
+    END_OF_STREAM,
+    ERROR,
   };
 
   // Callback for updating |total_bytes_decoded_|.
   void OnFrameDecoded(int buffer_size,
                       const DecodeCB& decode_cb,
                       Status status,
                       const scoped_refptr<VideoFrame>& video_frame);
 
+  // Runs |decode_cb| or puts it to |held_decode_callbacks_| depending on
+  // current value of |hold_decode_|.
+  void RunOrHoldDecode(const DecodeCB& decode_cb);
+
+  // Runs |decode_cb| with a frame from |decoded_frames_|.
+  void RunDecodeCallback(const DecodeCB& decode_cb);
+
   void DoReset();
 
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  base::ThreadChecker thread_checker_;
 
   const int decoding_delay_;
-
-  bool supports_get_decode_output_;
+  const bool supports_get_decode_output_;
+  const int max_parallel_decoding_requests_;
 
   State state_;
 
   CallbackHolder<PipelineStatusCB> init_cb_;
-  CallbackHolder<DecodeCB> decode_cb_;
   CallbackHolder<base::Closure> reset_cb_;
 
+  bool hold_decode_;
+  std::list<DecodeCB> held_decode_callbacks_;
+
   VideoDecoderConfig current_config_;
 
   std::list<scoped_refptr<VideoFrame> > decoded_frames_;
 
   int total_bytes_decoded_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FakeVideoDecoder> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FAKE_VIDEO_DECODER_H_