media/audio/audio_input_ipc.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_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_