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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_AUDIO_AUDIO_INPUT_IPC_H_
6 #define MEDIA_AUDIO_AUDIO_INPUT_IPC_H_
7 
8 #include "base/memory/shared_memory.h"
9 #include "base/sync_socket.h"
10 #include "media/audio/audio_parameters.h"
11 #include "media/base/media_export.h"
12 
13 namespace media {
14 
15 // Contains IPC notifications for the state of the server side
16 // (AudioInputController) audio state changes and when an AudioInputController
17 // has been created.  Implemented by AudioInputDevice.
18 class MEDIA_EXPORT AudioInputIPCDelegate {
19  public:
20   // Valid states for the input stream.
21   enum State {
22     kRecording,
23     kStopped,
24     kError,
25     kStateLast = kError
26   };
27 
28   // Called when an AudioInputController has been created.
29   // The shared memory |handle| points to a memory section that's used to
30   // transfer data between the AudioInputDevice and AudioInputController
31   // objects.  The implementation of OnStreamCreated takes ownership.
32   // The |socket_handle| is used by the AudioInputController to signal
33   // notifications that more data is available and can optionally provide
34   // parameter changes back.  The AudioInputDevice must read from this socket
35   // and process the shared memory whenever data is read from the socket.
36   virtual void OnStreamCreated(base::SharedMemoryHandle handle,
37                                base::SyncSocket::Handle socket_handle,
38                                int length,
39                                int total_segments) = 0;
40 
41   // Called when state of an audio stream has changed.
42   virtual void OnStateChanged(State state) = 0;
43 
44   // Called when the input stream volume has changed.
45   virtual void OnVolume(double volume) = 0;
46 
47   // Called when the AudioInputIPC object is going away and/or when the
48   // IPC channel has been closed and no more IPC requests can be made.
49   // Implementations should delete their owned AudioInputIPC instance
50   // immediately.
51   virtual void OnIPCClosed() = 0;
52 
53  protected:
54   virtual ~AudioInputIPCDelegate();
55 };
56 
57 // Provides IPC functionality for an AudioInputIPCDelegate (e.g., an
58 // AudioInputDevice).  The implementation should asynchronously deliver the
59 // messages to an AudioInputController object (or create one in the case of
60 // CreateStream()), that may live in a separate process.
61 class MEDIA_EXPORT AudioInputIPC {
62  public:
63   virtual ~AudioInputIPC();
64 
65   // Sends a request to create an AudioInputController object in the peer
66   // process, and configures it to use the specified audio |params|.  The
67   // |total_segments| indidates number of equal-lengthed segments in the shared
68   // memory buffer.  Once the stream has been created, the implementation will
69   // notify |delegate| by calling OnStreamCreated().
70   virtual void CreateStream(AudioInputIPCDelegate* delegate,
71                             int session_id,
72                             const AudioParameters& params,
73                             bool automatic_gain_control,
74                             uint32 total_segments) = 0;
75 
76   // Corresponds to a call to AudioInputController::Record() on the server side.
77   virtual void RecordStream() = 0;
78 
79   // Sets the volume of the audio stream.
80   virtual void SetVolume(double volume) = 0;
81 
82   // Closes the audio stream, which should shut down the corresponding
83   // AudioInputController in the peer process.
84   virtual void CloseStream() = 0;
85 };
86 
87 }  // namespace media
88 
89 #endif  // MEDIA_AUDIO_AUDIO_INPUT_IPC_H_
90