Implement AudioOutputProxy.

media/audio/audio_output_dispatcher.cc

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/audio/audio_output_dispatcher.h"
+
+#include "base/compiler_specific.h"
+#include "base/message_loop.h"
+#include "media/audio/audio_io.h"
+
+AudioOutputDispatcher::AudioOutputDispatcher(
+    AudioManager* audio_manager, const AudioParameters& params,
+    int close_delay_ms)
+    : audio_manager_(audio_manager),
+      message_loop_(audio_manager->GetMessageLoop()),
+      params_(params),
+      paused_proxies_(0),
+      ALLOW_THIS_IN_INITIALIZER_LIST(close_timer_(
+          base::TimeDelta::FromMilliseconds(close_delay_ms),
+          this, &AudioOutputDispatcher::ClosePendingStreams)) {
+}
+
+AudioOutputDispatcher::~AudioOutputDispatcher() {
+}
+
+bool AudioOutputDispatcher::StreamOpened() {
+  DCHECK_EQ(MessageLoop::current(), message_loop_);
+  paused_proxies_++;
+
+  // Ensure that there is at least one open stream.
+  if (streams_.empty() && !CreateAndOpenStream()) {
+    return false;
+  }
+
+  close_timer_.Reset();
+
+  return true;
+}
+
+AudioOutputStream* AudioOutputDispatcher::StreamStarted() {
+  DCHECK_EQ(MessageLoop::current(), message_loop_);
+
+  if (streams_.empty() && !CreateAndOpenStream()) {
+    return NULL;
+  }
+
+  AudioOutputStream* stream = streams_.back();
+  streams_.pop_back();
+
+  DCHECK_GT(paused_proxies_, 0u);
+  paused_proxies_--;
+
+  close_timer_.Reset();
+
+  // Schedule task to allocate streams for other proxies if we need to.
+  message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+      this, &AudioOutputDispatcher::OpenTask));
+
+  return stream;
+}
+
+void AudioOutputDispatcher::StreamStopped(AudioOutputStream* stream) {
+  DCHECK_EQ(MessageLoop::current(), message_loop_);
+  paused_proxies_++;
+  streams_.push_back(stream);
+  close_timer_.Reset();
+}
+
+void AudioOutputDispatcher::StreamClosed() {
+  DCHECK_EQ(MessageLoop::current(), message_loop_);
+
+  DCHECK_GT(paused_proxies_, 0u);
+  paused_proxies_--;
+
+  while (streams_.size() > paused_proxies_) {
+    streams_.back()->Close();
+    streams_.pop_back();
+  }
+}
+
+MessageLoop* AudioOutputDispatcher::message_loop() {
+  return message_loop_;
+}
+
+bool AudioOutputDispatcher::CreateAndOpenStream() {
+  AudioOutputStream* stream =
+      audio_manager_->MakeAudioOutputStream(params_);
+  if (!stream) {
+    return false;
+  }
+  if (!stream->Open()) {
+    stream->Close();
+    return false;
+  }
+  streams_.push_back(stream);
+  return true;
+}
+
+void AudioOutputDispatcher::OpenTask() {
+  // Make sure that we have at least one stream allocated if there
+  // are paused streams.
+  if (paused_proxies_ > 0 && streams_.empty()) {
+    CreateAndOpenStream();
+  }
+
+  close_timer_.Reset();
+}
+
+// This method is called by |close_timer_|.
+void AudioOutputDispatcher::ClosePendingStreams() {
+  while (!streams_.empty()) {
+    streams_.back()->Close();
+    streams_.pop_back();
+  }
+}