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 "media/base/decryptor.h"
  11 #include "media/base/demuxer_stream.h"
  12
  13 namespace base {
  14 class MessageLoopProxy;
  15 }
  16
  17 namespace media {
  18
  19 class DecoderBuffer;
  20
  21 // Decryptor-based DemuxerStream implementation that converts a potentially
  22 // encrypted demuxer stream to a clear demuxer stream.
  23 // All public APIs and callbacks are trampolined to the |message_loop_| so
  24 // that no locks are required for thread safety.
  25 class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
  26  public:
  27   DecryptingDemuxerStream(
  28       const scoped_refptr<base::MessageLoopProxy>& message_loop,
  29       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  30
  31   void Initialize(const scoped_refptr<DemuxerStream>& stream,
  32                   const PipelineStatusCB& status_cb);
  33   void Reset(const base::Closure& closure);
  34
  35   // DemuxerStream implementation.
  36   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  37   virtual const AudioDecoderConfig& audio_decoder_config() OVERRIDE;
  38   virtual const VideoDecoderConfig& video_decoder_config() OVERRIDE;
  39   virtual Type type() OVERRIDE;
  40   virtual void EnableBitstreamConverter() OVERRIDE;
  41
  42  protected:
  43   virtual ~DecryptingDemuxerStream();
  44
  45  private:
  46   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  47   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  48   // stabilizes.
  49   // TODO(xhwang): Update this diagram for DecryptingDemuxerStream.
  50   enum State {
  51     kUninitialized = 0,
  52     kDecryptorRequested,
  53     kIdle,
  54     kPendingDemuxerRead,
  55     kPendingDecrypt,
  56     kWaitingForKey,
  57   };
  58
  59   // Carries out the initialization operation scheduled by Initialize().
  60   void DoInitialize(const scoped_refptr<DemuxerStream>& stream,
  61                     const PipelineStatusCB& status_cb);
  62
  63   // Callback for DecryptorHost::RequestDecryptor().
  64   void SetDecryptor(Decryptor* decryptor);
  65
  66   // Callback for DemuxerStream::Read().
  67   void DecryptBuffer(DemuxerStream::Status status,
  68                      const scoped_refptr<DecoderBuffer>& buffer);
  69
  70   // Carries out the buffer decryption operation scheduled by DecryptBuffer().
  71   void DoDecryptBuffer(DemuxerStream::Status status,
  72                        const scoped_refptr<DecoderBuffer>& buffer);
  73
  74   void DecryptPendingBuffer();
  75
  76   // Callback for Decryptor::Decrypt().
  77   void DeliverBuffer(Decryptor::Status status,
  78                      const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  79
  80   // Carries out the frame delivery operation scheduled by DeliverBuffer().
  81   void DoDeliverBuffer(Decryptor::Status status,
  82                        const scoped_refptr<DecoderBuffer>& decrypted_buffer);
  83
  84   // Callback for the |decryptor_| to notify this object that a new key has been
  85   // added.
  86   void OnKeyAdded();
  87
  88   // Resets decoder and calls |reset_cb_|.
  89   void DoReset();
  90
  91   // Returns Decryptor::StreamType converted from |stream_type_|.
  92   Decryptor::StreamType GetDecryptorStreamType() const;
  93
  94   // Sets |{audio|video}_config_| from |stream|.
  95   void SetDecoderConfig(const scoped_refptr<DemuxerStream>& stream);
  96
  97   scoped_refptr<base::MessageLoopProxy> message_loop_;
  98
  99   State state_;
 100
 101   PipelineStatusCB init_cb_;
 102   ReadCB read_cb_;
 103   base::Closure reset_cb_;
 104
 105   // Pointer to the input demuxer stream that will feed us encrypted buffers.
 106   scoped_refptr<DemuxerStream> demuxer_stream_;
 107
 108   Type stream_type_;
 109   scoped_ptr<AudioDecoderConfig> audio_config_;
 110   scoped_ptr<VideoDecoderConfig> video_config_;
 111
 112   // Callback to request/cancel decryptor creation notification.
 113   SetDecryptorReadyCB set_decryptor_ready_cb_;
 114
 115   Decryptor* decryptor_;
 116
 117   // The buffer returned by the demuxer that needs to be decrypted.
 118   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decrypt_;
 119
 120   // Indicates the situation where new key is added during pending decryption
 121   // (in other words, this variable can only be set in state kPendingDecrypt).
 122   // If this variable is true and kNoKey is returned then we need to try
 123   // decrypting again in case the newly added key is the correct decryption key.
 124   bool key_added_while_decrypt_pending_;
 125
 126   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 127 };
 128
 129 }  // namespace media
 130
 131 #endif  // MEDIA_FILTERS_DECRYPTING_DEMUXER_STREAM_H_