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      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_DEMUXER_STREAM_H_
      6 #define MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_
      7 
      8 #include "base/callback.h"
      9 #include "base/memory/ref_counted.h"
     10 #include "base/memory/weak_ptr.h"
     11 #include "media/base/audio_decoder_config.h"
     12 #include "media/base/decryptor.h"
     13 #include "media/base/demuxer_stream.h"
     14 #include "media/base/pipeline_status.h"
     15 #include "media/base/video_decoder_config.h"
     16 
     17 namespace base {
     18 class SingleThreadTaskRunner;
     19 }
     20 
     21 namespace media {
     22 
     23 class DecoderBuffer;
     24 
     25 // Decryptor-based DemuxerStream implementation that converts a potentially
     26 // encrypted demuxer stream to a clear demuxer stream.
     27 // All public APIs and callbacks are trampolined to the |task_runner_| so
     28 // that no locks are required for thread safety.
     29 class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
     30  public:
     31   DecryptingDemuxerStream(
     32       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     33       const SetDecryptorReadyCB& set_decryptor_ready_cb);
     34 
     35   // Cancels all pending operations immediately and fires all pending callbacks.
     36   virtual ~DecryptingDemuxerStream();
     37 
     38   void Initialize(DemuxerStream* stream,
     39                   const PipelineStatusCB& status_cb);
     40 
     41   // Cancels all pending operations and fires all pending callbacks. If in
     42   // kPendingDemuxerRead or kPendingDecrypt state, waits for the pending
     43   // operation to finish before satisfying |closure|. Sets the state to
     44   // kUninitialized if |this| hasn't been initialized, or to kIdle otherwise.
     45   void Reset(const base::Closure& closure);
     46 
     47   // DemuxerStream implementation.
     48   virtual void Read(const ReadCB& read_cb) OVERRIDE;
     49   virtual AudioDecoderConfig audio_decoder_config() OVERRIDE;
     50   virtual VideoDecoderConfig video_decoder_config() OVERRIDE;
     51   virtual Type type() OVERRIDE;
     52   virtual void EnableBitstreamConverter() OVERRIDE;
     53   virtual bool SupportsConfigChanges() OVERRIDE;
     54   virtual VideoRotation video_rotation() OVERRIDE;
     55 
     56  private:
     57   // For a detailed state diagram please see this link: http://goo.gl/8jAok
     58   // TODO(xhwang): Add a ASCII state diagram in this file after this class
     59   // stabilizes.
     60   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
     61   enum State {
     62     kUninitialized = 0,
     63     kDecryptorRequested,
     64     kIdle,
     65     kPendingDemuxerRead,
     66     kPendingDecrypt,
     67     kWaitingForKey
     68   };
     69 
     70   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
     71   // called when the decryptor has been completely attached to the pipeline.
     72   void SetDecryptor(Decryptor* decryptor,
     73                     const DecryptorAttachedCB& decryptor_attached_cb);
     74 
     75   // Callback for DemuxerStream::Read().
     76   void DecryptBuffer(DemuxerStream::Status status,
     77                      const scoped_refptr<DecoderBuffer>& buffer);
     78 
     79   void DecryptPendingBuffer();
     80 
     81   // Callback for Decryptor::Decrypt().
     82   void DeliverBuffer(Decryptor::Status status,
     83                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
     84 
     85   // Callback for the |decryptor_| to notify this object that a new key has been
     86   // added.
     87   void OnKeyAdded();
     88 
     89   // Resets decoder and calls |reset_cb_|.
     90   void DoReset();
     91 
     92   // Returns Decryptor::StreamType converted from |stream_type_|.
     93   Decryptor::StreamType GetDecryptorStreamType() const;
     94 
     95   // Creates and initializes either |audio_config_| or |video_config_| based on
     96   // |demuxer_stream_|.
     97   void InitializeDecoderConfig();
     98 
     99   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
    100 
    101   State state_;
    102 
    103   PipelineStatusCB init_cb_;
    104   ReadCB read_cb_;
    105   base::Closure reset_cb_;
    106 
    107   // Pointer to the input demuxer stream that will feed us encrypted buffers.
    108   DemuxerStream* demuxer_stream_;
    109 
    110   AudioDecoderConfig audio_config_;
    111   VideoDecoderConfig video_config_;
    112 
    113   // Callback to request/cancel decryptor creation notification.
    114   SetDecryptorReadyCB set_decryptor_ready_cb_;
    115 
    116   Decryptor* decryptor_;
    117 
    118   // The buffer returned by the demuxer that needs to be decrypted.
    119   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
    120 
    121   // Indicates the situation where new key is added during pending decryption
    122   // (in other words, this variable can only be set in state kPendingDecrypt).
    123   // If this variable is true and kNoKey is returned then we need to try
    124   // decrypting again in case the newly added key is the correct decryption key.
    125   bool key_added_while_decrypt_pending_;
    126 
    127   // NOTE: Weak pointers must be invalidated before all other member variables.
    128   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
    129   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
    130 
    131   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
    132 };
    133 
    134 }  // namespace media
    135 
    136 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_
    137