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   };
  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,
  38                                int total_segments) = 0;
  39
  40   // Called when state of an audio stream has changed.
  41   virtual void OnStateChanged(State state) = 0;
  42
  43   // Called when the input stream volume has changed.
  44   virtual void OnVolume(double volume) = 0;
  45
  46   // Called when the AudioInputIPC object is going away and/or when the
  47   // IPC channel has been closed and no more IPC requests can be made.
  48   // Implementations should delete their owned AudioInputIPC instance
  49   // immediately.
  50   virtual void OnIPCClosed() = 0;
  51
  52  protected:
  53   virtual ~AudioInputIPCDelegate();
  54 };
  55
  56 // Provides IPC functionality for an AudioInputIPCDelegate (e.g., an
  57 // AudioInputDevice).  The implementation should asynchronously deliver the
  58 // messages to an AudioInputController object (or create one in the case of
  59 // CreateStream()), that may live in a separate process.
  60 class MEDIA_EXPORT AudioInputIPC {
  61  public:
  62   virtual ~AudioInputIPC();
  63
  64   // Sends a request to create an AudioInputController object in the peer
  65   // process, and configures it to use the specified audio |params|.  The
  66   // |total_segments| indidates number of equal-lengthed segments in the shared
  67   // memory buffer.  Once the stream has been created, the implementation will
  68   // notify |delegate| by calling OnStreamCreated().
  69   virtual void CreateStream(AudioInputIPCDelegate* delegate,
  70                             int session_id,
  71                             const AudioParameters& params,
  72                             bool automatic_gain_control,
  73                             uint32 total_segments) = 0;
  74
  75   // Corresponds to a call to AudioInputController::Record() on the server side.
  76   virtual void RecordStream() = 0;
  77
  78   // Sets the volume of the audio stream.
  79   virtual void SetVolume(double volume) = 0;
  80
  81   // Closes the audio stream, which should shut down the corresponding
  82   // AudioInputController in the peer process.
  83   virtual void CloseStream() = 0;
  84 };
  85
  86 }  // namespace media
  87
  88 #endif  // MEDIA_AUDIO_AUDIO_INPUT_IPC_H_