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 SingleThreadTaskRunner;
  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 |task_runner_| 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::SingleThreadTaskRunner>& task_runner,
  31       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  32   virtual ~DecryptingVideoDecoder();
  33
  34   // VideoDecoder implementation.
  35   virtual void Initialize(const VideoDecoderConfig& config,
  36                           bool low_delay,
  37                           const PipelineStatusCB& status_cb,
  38                           const OutputCB& output_cb) OVERRIDE;
  39   virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  40                       const DecodeCB& decode_cb) OVERRIDE;
  41   virtual void Reset(const base::Closure& closure) OVERRIDE;
  42
  43  private:
  44   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  45   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  46   // stabilizes.
  47   enum State {
  48     kUninitialized = 0,
  49     kDecryptorRequested,
  50     kPendingDecoderInit,
  51     kIdle,
  52     kPendingDecode,
  53     kWaitingForKey,
  54     kDecodeFinished,
  55     kError
  56   };
  57
  58   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  59   // called when the decryptor has been completely attached to the pipeline.
  60   void SetDecryptor(Decryptor* decryptor,
  61                     const DecryptorAttachedCB& decryptor_attached_cb);
  62
  63   // Callback for Decryptor::InitializeVideoDecoder() during initialization.
  64   void FinishInitialization(bool success);
  65
  66   void DecodePendingBuffer();
  67
  68   // Callback for Decryptor::DecryptAndDecodeVideo().
  69   void DeliverFrame(int buffer_size,
  70                     Decryptor::Status status,
  71                     const scoped_refptr<VideoFrame>& frame);
  72
  73   // Callback for the |decryptor_| to notify this object that a new key has been
  74   // added.
  75   void OnKeyAdded();
  76
  77   // Reset decoder and call |reset_cb_|.
  78   void DoReset();
  79
  80   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  81
  82   State state_;
  83
  84   PipelineStatusCB init_cb_;
  85   OutputCB output_cb_;
  86   DecodeCB decode_cb_;
  87   base::Closure reset_cb_;
  88
  89   VideoDecoderConfig config_;
  90
  91   // Callback to request/cancel decryptor creation notification.
  92   SetDecryptorReadyCB set_decryptor_ready_cb_;
  93
  94   Decryptor* decryptor_;
  95
  96   // The buffer that needs decrypting/decoding.
  97   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
  98
  99   // Indicates the situation where new key is added during pending decode
 100   // (in other words, this variable can only be set in state kPendingDecode).
 101   // If this variable is true and kNoKey is returned then we need to try
 102   // decrypting/decoding again in case the newly added key is the correct
 103   // decryption key.
 104   bool key_added_while_decode_pending_;
 105
 106   // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
 107   // matching DecryptCB call (in DoDeliverFrame()).
 108   uint32 trace_id_;
 109
 110   // NOTE: Weak pointers must be invalidated before all other member variables.
 111   base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
 112   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
 113
 114   DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
 115 };
 116
 117 }  // namespace media
 118
 119 #endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_