media/audio/audio_output_proxy.cc

   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 #include "media/audio/audio_output_proxy.h"
   6
   7 #include "base/logging.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "media/audio/audio_manager.h"
  10 #include "media/audio/audio_output_dispatcher.h"
  11
  12 namespace media {
  13
  14 AudioOutputProxy::AudioOutputProxy(AudioOutputDispatcher* dispatcher)
  15     : dispatcher_(dispatcher),
  16       state_(kCreated),
  17       volume_(1.0) {
  18 }
  19
  20 AudioOutputProxy::~AudioOutputProxy() {
  21   DCHECK(CalledOnValidThread());
  22   DCHECK(state_ == kCreated || state_ == kClosed) << "State is: " << state_;
  23 }
  24
  25 bool AudioOutputProxy::Open() {
  26   DCHECK(CalledOnValidThread());
  27   DCHECK_EQ(state_, kCreated);
  28
  29   if (!dispatcher_->OpenStream()) {
  30     state_ = kOpenError;
  31     return false;
  32   }
  33
  34   state_ = kOpened;
  35   return true;
  36 }
  37
  38 void AudioOutputProxy::Start(AudioSourceCallback* callback) {
  39   DCHECK(CalledOnValidThread());
  40
  41   // We need to support both states since the callback may not handle OnError()
  42   // immediately (or at all).  It's also possible for subsequent StartStream()
  43   // calls to succeed after failing, so we allow it to be called again.
  44   DCHECK(state_ == kOpened || state_ == kStartError);
  45
  46   if (!dispatcher_->StartStream(callback, this)) {
  47     state_ = kStartError;
  48     callback->OnError(this);
  49     return;
  50   }
  51   state_ = kPlaying;
  52 }
  53
  54 void AudioOutputProxy::Stop() {
  55   DCHECK(CalledOnValidThread());
  56   if (state_ != kPlaying)
  57     return;
  58
  59   dispatcher_->StopStream(this);
  60   state_ = kOpened;
  61 }
  62
  63 void AudioOutputProxy::SetVolume(double volume) {
  64   DCHECK(CalledOnValidThread());
  65   volume_ = volume;
  66   dispatcher_->StreamVolumeSet(this, volume);
  67 }
  68
  69 void AudioOutputProxy::GetVolume(double* volume) {
  70   DCHECK(CalledOnValidThread());
  71   *volume = volume_;
  72 }
  73
  74 void AudioOutputProxy::Close() {
  75   DCHECK(CalledOnValidThread());
  76   DCHECK(state_ == kCreated || state_ == kOpenError || state_ == kOpened ||
  77          state_ == kStartError);
  78
  79   // kStartError means OpenStream() succeeded and the stream must be closed
  80   // before destruction.
  81   if (state_ != kCreated && state_ != kOpenError)
  82     dispatcher_->CloseStream(this);
  83
  84   state_ = kClosed;
  85
  86   // Delete the object now like is done in the Close() implementation of
  87   // physical stream objects.  If we delete the object via DeleteSoon, we
  88   // unnecessarily complicate the Shutdown procedure of the
  89   // dispatcher+audio manager.
  90   delete this;
  91 }
  92
  93 }  // namespace media