audio_input_ipc.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
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/shared_memory.h"
9#include "base/sync_socket.h"
10#include "media/audio/audio_parameters.h"
11#include "media/base/media_export.h"
12
13namespace 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.
18class MEDIA_EXPORT AudioInputIPCDelegate {
19 public:
20  // Valid states for the input stream.
21  enum State {
22    kRecording,
23    kStopped,
24    kError
25  };
26
27  // Called when an AudioInputController has been created.
28  // The shared memory |handle| points to a memory section that's used to
29  // transfer data between the AudioInputDevice and AudioInputController
30  // objects.  The implementation of OnStreamCreated takes ownership.
31  // The |socket_handle| is used by the AudioInputController to signal
32  // notifications that more data is available and can optionally provide
33  // parameter changes back.  The AudioInputDevice must read from this socket
34  // and process the shared memory whenever data is read from the socket.
35  virtual void OnStreamCreated(base::SharedMemoryHandle handle,
36                               base::SyncSocket::Handle socket_handle,
37                               int length) = 0;
38
39  // Called when state of an audio stream has changed.
40  virtual void OnStateChanged(State state) = 0;
41
42  // Called when the input stream volume has changed.
43  virtual void OnVolume(double volume) = 0;
44
45  // Called when a device has been started on the server side.
46  // If the device could not be started, |device_id| will be empty.
47  virtual void OnDeviceReady(const std::string& device_id) = 0;
48
49  // Called when the AudioInputIPC object is going away and/or when the
50  // IPC channel has been closed and no more IPC requests can be made.
51  // Implementations must clear any references to the AudioInputIPC object
52  // at this point.
53  virtual void OnIPCClosed() = 0;
54
55 protected:
56  virtual ~AudioInputIPCDelegate();
57};
58
59// Provides IPC functionality for an AudioInputDevice.  The implementation
60// should asynchronously deliver the messages to an AudioInputController object
61// (or create one in the case of CreateStream()), that may live in a separate
62// process.
63class MEDIA_EXPORT AudioInputIPC {
64 public:
65  // Registers an AudioInputIPCDelegate and returns a |stream_id| that
66  // must be used with all other IPC functions in this interface.
67  virtual int AddDelegate(AudioInputIPCDelegate* delegate) = 0;
68
69  // Unregisters a delegate that was previously registered via a call to
70  // AddDelegate().  The audio stream should be in a closed state prior to
71  // calling this function.
72  virtual void RemoveDelegate(int stream_id) = 0;
73
74  // Sends a request to create an AudioInputController object in the peer
75  // process, identify it by |stream_id| and configure it to use the specified
76  // audio |params|.  Once the stream has been created, the implementation must
77  // generate a notification to the AudioInputIPCDelegate and call
78  // OnStreamCreated().
79  virtual void CreateStream(int stream_id, const AudioParameters& params,
80      const std::string& device_id, bool automatic_gain_control) = 0;
81
82  // Starts the device on the server side.  Once the device has started,
83  // or failed to start, a callback to
84  // AudioInputIPCDelegate::OnDeviceReady() must be made.
85  virtual void StartDevice(int stream_id, int session_id) = 0;
86
87  // Corresponds to a call to AudioInputController::Record() on the server side.
88  virtual void RecordStream(int stream_id) = 0;
89
90  // Sets the volume of the audio stream.
91  virtual void SetVolume(int stream_id, double volume) = 0;
92
93  // Closes the audio stream and deletes the matching AudioInputController
94  // instance.  Prior to deleting the AudioInputController object, a call to
95  // AudioInputController::Close must be made.
96  virtual void CloseStream(int stream_id) = 0;
97
98 protected:
99  virtual ~AudioInputIPC();
100};
101
102}  // namespace media
103
104#endif  // MEDIA_AUDIO_AUDIO_INPUT_IPC_H_
105