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
14namespace base {
15class SingleThreadTaskRunner;
16}
17
18namespace media {
19
20class DecoderBuffer;
21class 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.
27class 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 std::string GetDisplayName() const OVERRIDE;
36  virtual void Initialize(const VideoDecoderConfig& config,
37                          bool low_delay,
38                          const PipelineStatusCB& status_cb,
39                          const OutputCB& output_cb) OVERRIDE;
40  virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
41                      const DecodeCB& decode_cb) OVERRIDE;
42  virtual void Reset(const base::Closure& closure) OVERRIDE;
43
44 private:
45  // For a detailed state diagram please see this link: http://goo.gl/8jAok
46  // TODO(xhwang): Add a ASCII state diagram in this file after this class
47  // stabilizes.
48  enum State {
49    kUninitialized = 0,
50    kDecryptorRequested,
51    kPendingDecoderInit,
52    kIdle,
53    kPendingDecode,
54    kWaitingForKey,
55    kDecodeFinished,
56    kError
57  };
58
59  // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
60  // called when the decryptor has been completely attached to the pipeline.
61  void SetDecryptor(Decryptor* decryptor,
62                    const DecryptorAttachedCB& decryptor_attached_cb);
63
64  // Callback for Decryptor::InitializeVideoDecoder() during initialization.
65  void FinishInitialization(bool success);
66
67  void DecodePendingBuffer();
68
69  // Callback for Decryptor::DecryptAndDecodeVideo().
70  void DeliverFrame(int buffer_size,
71                    Decryptor::Status status,
72                    const scoped_refptr<VideoFrame>& frame);
73
74  // Callback for the |decryptor_| to notify this object that a new key has been
75  // added.
76  void OnKeyAdded();
77
78  // Reset decoder and call |reset_cb_|.
79  void DoReset();
80
81  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
82
83  State state_;
84
85  PipelineStatusCB init_cb_;
86  OutputCB output_cb_;
87  DecodeCB decode_cb_;
88  base::Closure reset_cb_;
89
90  VideoDecoderConfig config_;
91
92  // Callback to request/cancel decryptor creation notification.
93  SetDecryptorReadyCB set_decryptor_ready_cb_;
94
95  Decryptor* decryptor_;
96
97  // The buffer that needs decrypting/decoding.
98  scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
99
100  // Indicates the situation where new key is added during pending decode
101  // (in other words, this variable can only be set in state kPendingDecode).
102  // If this variable is true and kNoKey is returned then we need to try
103  // decrypting/decoding again in case the newly added key is the correct
104  // decryption key.
105  bool key_added_while_decode_pending_;
106
107  // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
108  // matching DecryptCB call (in DoDeliverFrame()).
109  uint32 trace_id_;
110
111  // NOTE: Weak pointers must be invalidated before all other member variables.
112  base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
113  base::WeakPtr<DecryptingVideoDecoder> weak_this_;
114
115  DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
116};
117
118}  // namespace media
119
120#endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
121