media/filters/decrypting_demuxer_stream.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_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   virtual ~DecryptingDemuxerStream();
  35
  36   void Initialize(DemuxerStream* stream,
  37                   const PipelineStatusCB& status_cb);
  38
  39   // Cancels all pending operations and fires all pending callbacks. If in
  40   // kPendingDemuxerRead or kPendingDecrypt state, waits for the pending
  41   // operation to finish before satisfying |closure|. Sets the state to
  42   // kUninitialized if |this| hasn't been initialized, or to kIdle otherwise.
  43   void Reset(const base::Closure& closure);
  44
  45   // Cancels all pending operations immediately and fires all pending callbacks
  46   // and sets the state to kStopped. Does NOT wait for any pending operations.
  47   // Note: During the teardown process, media pipeline will be waiting on the
  48   // render main thread. If a Decryptor depends on the render main thread
  49   // (e.g. PpapiDecryptor), the pending DecryptCB would not be satisfied.
  50   void Stop(const base::Closure& closure);
  51
  52   // DemuxerStream implementation.
  53   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  54   virtual AudioDecoderConfig audio_decoder_config() OVERRIDE;
  55   virtual VideoDecoderConfig video_decoder_config() OVERRIDE;
  56   virtual Type type() OVERRIDE;
  57   virtual void EnableBitstreamConverter() OVERRIDE;
  58   virtual bool SupportsConfigChanges() OVERRIDE;
  59
  60  private:
  61   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  62   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  63   // stabilizes.
  64   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  65   enum State {
  66     kUninitialized = 0,
  67     kDecryptorRequested,
  68     kIdle,
  69     kPendingDemuxerRead,
  70     kPendingDecrypt,
  71     kWaitingForKey,
  72     kStopped
  73   };
  74
  75   // Callback for DecryptorHost::RequestDecryptor().
  76   void SetDecryptor(Decryptor* decryptor);
  77
  78   // Callback for DemuxerStream::Read().
  79   void DecryptBuffer(DemuxerStream::Status status,
  80                      const scoped_refptr<DecoderBuffer>& buffer);
  81
  82   void DecryptPendingBuffer();
  83
  84   // Callback for Decryptor::Decrypt().
  85   void DeliverBuffer(Decryptor::Status status,
  86                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  87
  88   // Callback for the |decryptor_| to notify this object that a new key has been
  89   // added.
  90   void OnKeyAdded();
  91
  92   // Resets decoder and calls |reset_cb_|.
  93   void DoReset();
  94
  95   // Returns Decryptor::StreamType converted from |stream_type_|.
  96   Decryptor::StreamType GetDecryptorStreamType() const;
  97
  98   // Creates and initializes either |audio_config_| or |video_config_| based on
  99   // |demuxer_stream_|.
 100   void InitializeDecoderConfig();
 101
 102   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 103
 104   State state_;
 105
 106   PipelineStatusCB init_cb_;
 107   ReadCB read_cb_;
 108   base::Closure reset_cb_;
 109
 110   // Pointer to the input demuxer stream that will feed us encrypted buffers.
 111   DemuxerStream* demuxer_stream_;
 112
 113   AudioDecoderConfig audio_config_;
 114   VideoDecoderConfig video_config_;
 115
 116   // Callback to request/cancel decryptor creation notification.
 117   SetDecryptorReadyCB set_decryptor_ready_cb_;
 118
 119   Decryptor* decryptor_;
 120
 121   // The buffer returned by the demuxer that needs to be decrypted.
 122   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 123
 124   // Indicates the situation where new key is added during pending decryption
 125   // (in other words, this variable can only be set in state kPendingDecrypt).
 126   // If this variable is true and kNoKey is returned then we need to try
 127   // decrypting again in case the newly added key is the correct decryption key.
 128   bool key_added_while_decrypt_pending_;
 129
 130   // NOTE: Weak pointers must be invalidated before all other member variables.
 131   base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
 132   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
 133
 134   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 135 };
 136
 137 }  // namespace media
 138
 139 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_