media/filters/decrypting_video_decoder.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
   6 #define MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "media/base/decryptor.h"
  11 #include "media/base/video_decoder.h"
  12 #include "media/base/video_decoder_config.h"
  13
  14 namespace base {
  15 class MessageLoopProxy;
  16 }
  17
  18 namespace media {
  19
  20 class DecoderBuffer;
  21 class Decryptor;
  22
  23 // Decryptor-based VideoDecoder implementation that can decrypt and decode
  24 // encrypted video buffers and return decrypted and decompressed video frames.
  25 // All public APIs and callbacks are trampolined to the |message_loop_| so
  26 // that no locks are required for thread safety.
  27 class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
  28  public:
  29   DecryptingVideoDecoder(
  30       const scoped_refptr<base::MessageLoopProxy>& message_loop,
  31       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  32   virtual ~DecryptingVideoDecoder();
  33
  34   // VideoDecoder implementation.
  35   virtual void Initialize(const VideoDecoderConfig& config,
  36                           const PipelineStatusCB& status_cb) OVERRIDE;
  37   virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  38                       const DecodeCB& decode_cb) OVERRIDE;
  39   virtual void Reset(const base::Closure& closure) OVERRIDE;
  40   virtual void Stop(const base::Closure& closure) OVERRIDE;
  41
  42  private:
  43   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  44   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  45   // stabilizes.
  46   enum State {
  47     kUninitialized = 0,
  48     kDecryptorRequested,
  49     kPendingDecoderInit,
  50     kIdle,
  51     kPendingDecode,
  52     kWaitingForKey,
  53     kDecodeFinished,
  54     kStopped,
  55     kError
  56   };
  57
  58   // Callback for DecryptorHost::RequestDecryptor().
  59   void SetDecryptor(Decryptor* decryptor);
  60
  61   // Callback for Decryptor::InitializeVideoDecoder() during initialization.
  62   void FinishInitialization(bool success);
  63
  64   void DecodePendingBuffer();
  65
  66   // Callback for Decryptor::DecryptAndDecodeVideo().
  67   void DeliverFrame(int buffer_size,
  68                     Decryptor::Status status,
  69                     const scoped_refptr<VideoFrame>& frame);
  70
  71   // Callback for the |decryptor_| to notify this object that a new key has been
  72   // added.
  73   void OnKeyAdded();
  74
  75   // Reset decoder and call |reset_cb_|.
  76   void DoReset();
  77
  78   // Free decoder resources and call |stop_cb_|.
  79   void DoStop();
  80
  81   scoped_refptr<base::MessageLoopProxy> message_loop_;
  82   base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
  83   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
  84
  85   State state_;
  86
  87   PipelineStatusCB init_cb_;
  88   DecodeCB decode_cb_;
  89   base::Closure reset_cb_;
  90
  91   VideoDecoderConfig config_;
  92
  93   // Callback to request/cancel decryptor creation notification.
  94   SetDecryptorReadyCB set_decryptor_ready_cb_;
  95
  96   Decryptor* decryptor_;
  97
  98   // The buffer that needs decrypting/decoding.
  99   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
 100
 101   // Indicates the situation where new key is added during pending decode
 102   // (in other words, this variable can only be set in state kPendingDecode).
 103   // If this variable is true and kNoKey is returned then we need to try
 104   // decrypting/decoding again in case the newly added key is the correct
 105   // decryption key.
 106   bool key_added_while_decode_pending_;
 107
 108   // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
 109   // matching DecryptCB call (in DoDeliverFrame()).
 110   uint32 trace_id_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
 113 };
 114
 115 }  // namespace media
 116
 117 #endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_