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       const base::Closure& waiting_for_decryption_key_cb);
  33   ~DecryptingVideoDecoder() override;
  34
  35   // VideoDecoder implementation.
  36   std::string GetDisplayName() const override;
  37   void Initialize(const VideoDecoderConfig& config,
  38                   bool low_delay,
  39                   const PipelineStatusCB& status_cb,
  40                   const OutputCB& output_cb) override;
  41   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  42               const DecodeCB& decode_cb) override;
  43   void Reset(const base::Closure& closure) override;
  44
  45   static const char kDecoderName[];
  46
  47  private:
  48   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  49   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  50   // stabilizes.
  51   enum State {
  52     kUninitialized = 0,
  53     kDecryptorRequested,
  54     kPendingDecoderInit,
  55     kIdle,
  56     kPendingDecode,
  57     kWaitingForKey,
  58     kDecodeFinished,
  59     kError
  60   };
  61
  62   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  63   // called when the decryptor has been completely attached to the pipeline.
  64   void SetDecryptor(Decryptor* decryptor,
  65                     const DecryptorAttachedCB& decryptor_attached_cb);
  66
  67   // Callback for Decryptor::InitializeVideoDecoder() during initialization.
  68   void FinishInitialization(bool success);
  69
  70   void DecodePendingBuffer();
  71
  72   // Callback for Decryptor::DecryptAndDecodeVideo().
  73   void DeliverFrame(int buffer_size,
  74                     Decryptor::Status status,
  75                     const scoped_refptr<VideoFrame>& frame);
  76
  77   // Callback for the |decryptor_| to notify this object that a new key has been
  78   // added.
  79   void OnKeyAdded();
  80
  81   // Reset decoder and call |reset_cb_|.
  82   void DoReset();
  83
  84   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  85
  86   State state_;
  87
  88   PipelineStatusCB init_cb_;
  89   OutputCB output_cb_;
  90   DecodeCB decode_cb_;
  91   base::Closure reset_cb_;
  92   base::Closure waiting_for_decryption_key_cb_;
  93
  94   VideoDecoderConfig config_;
  95
  96   // Callback to request/cancel decryptor creation notification.
  97   SetDecryptorReadyCB set_decryptor_ready_cb_;
  98
  99   Decryptor* decryptor_;
 100
 101   // The buffer that needs decrypting/decoding.
 102   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
 103
 104   // Indicates the situation where new key is added during pending decode
 105   // (in other words, this variable can only be set in state kPendingDecode).
 106   // If this variable is true and kNoKey is returned then we need to try
 107   // decrypting/decoding again in case the newly added key is the correct
 108   // decryption key.
 109   bool key_added_while_decode_pending_;
 110
 111   // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
 112   // matching DecryptCB call (in DoDeliverFrame()).
 113   uint32 trace_id_;
 114
 115   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
 116   base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
 117
 118   DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
 119 };
 120
 121 }  // namespace media
 122
 123 #endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_