2 files changed, 54 insertions, 21 deletions

diff --git a/media/audio/audio_output_dispatcher.cc b/media/audio/audio_output_dispatcher.cc
index 3f9d848..c707069 100644
--- a/media/audio/audio_output_dispatcher.cc
+++ b/media/audio/audio_output_dispatcher.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -6,6 +6,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
+#include "base/time.h"
 #include "media/audio/audio_io.h"
 
 AudioOutputDispatcher::AudioOutputDispatcher(
@@ -14,6 +15,8 @@ AudioOutputDispatcher::AudioOutputDispatcher(
     : audio_manager_(audio_manager),
       message_loop_(audio_manager->GetMessageLoop()),
       params_(params),
+      pause_delay_milliseconds_(2 * params.samples_per_packet *
+          base::Time::kMillisecondsPerSecond / params.sample_rate),
       paused_proxies_(0),
       ALLOW_THIS_IN_INITIALIZER_LIST(close_timer_(
           base::TimeDelta::FromMilliseconds(close_delay_ms),
@@ -28,7 +31,7 @@ bool AudioOutputDispatcher::StreamOpened() {
   paused_proxies_++;
 
   // Ensure that there is at least one open stream.
-  if (streams_.empty() && !CreateAndOpenStream()) {
+  if (idle_streams_.empty() && !CreateAndOpenStream()) {
     return false;
   }
 
@@ -40,12 +43,12 @@ bool AudioOutputDispatcher::StreamOpened() {
 AudioOutputStream* AudioOutputDispatcher::StreamStarted() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
 
-  if (streams_.empty() && !CreateAndOpenStream()) {
+  if (idle_streams_.empty() && !CreateAndOpenStream()) {
     return NULL;
   }
 
-  AudioOutputStream* stream = streams_.back();
-  streams_.pop_back();
+  AudioOutputStream* stream = idle_streams_.back();
+  idle_streams_.pop_back();
 
   DCHECK_GT(paused_proxies_, 0u);
   paused_proxies_--;
@@ -61,20 +64,41 @@ AudioOutputStream* AudioOutputDispatcher::StreamStarted() {
 
 void AudioOutputDispatcher::StreamStopped(AudioOutputStream* stream) {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
+
   paused_proxies_++;
-  streams_.push_back(stream);
+
+  pausing_streams_.push_front(stream);
   close_timer_.Reset();
+
+  // Don't recycle stream until two buffers worth of time has elapsed.
+  message_loop_->PostDelayedTask(
+      FROM_HERE,
+      NewRunnableMethod(this, &AudioOutputDispatcher::StopStreamTask),
+      pause_delay_milliseconds_);
+}
+
+void AudioOutputDispatcher::StopStreamTask() {
+  if (pausing_streams_.empty())
+    return;
+  AudioOutputStream* stream = pausing_streams_.back();
+  pausing_streams_.pop_back();
+  idle_streams_.push_back(stream);
 }
 
 void AudioOutputDispatcher::StreamClosed() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
 
+  while (!pausing_streams_.empty()) {
+    idle_streams_.push_back(pausing_streams_.back());
+    pausing_streams_.pop_back();
+  }
+
   DCHECK_GT(paused_proxies_, 0u);
   paused_proxies_--;
 
-  while (streams_.size() > paused_proxies_) {
-    streams_.back()->Close();
-    streams_.pop_back();
+  while (idle_streams_.size() > paused_proxies_) {
+    idle_streams_.back()->Close();
+    idle_streams_.pop_back();
   }
 }
 
@@ -92,14 +116,15 @@ bool AudioOutputDispatcher::CreateAndOpenStream() {
     stream->Close();
     return false;
   }
-  streams_.push_back(stream);
+  idle_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()) {
+  if (paused_proxies_ > 0 && idle_streams_.empty() &&
+      pausing_streams_.empty()) {
     CreateAndOpenStream();
   }
 
@@ -108,8 +133,8 @@ void AudioOutputDispatcher::OpenTask() {
 
 // This method is called by |close_timer_|.
 void AudioOutputDispatcher::ClosePendingStreams() {
-  while (!streams_.empty()) {
-    streams_.back()->Close();
-    streams_.pop_back();
+  while (!idle_streams_.empty()) {
+    idle_streams_.back()->Close();
+    idle_streams_.pop_back();
   }
 }
diff --git a/media/audio/audio_output_dispatcher.h b/media/audio/audio_output_dispatcher.h
index 2289e89..18e1b28 100644
--- a/media/audio/audio_output_dispatcher.h
+++ b/media/audio/audio_output_dispatcher.h
@@ -22,6 +22,7 @@
 #define MEDIA_AUDIO_AUDIO_OUTPUT_DISPATCHER_H_
 
 #include <vector>
+#include <list>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
@@ -43,19 +44,20 @@ class AudioOutputDispatcher
   ~AudioOutputDispatcher();
 
   // Called by AudioOutputProxy when the stream is closed. Opens a new
-  // physical stream if there are no pending streams in |streams_|.
+  // physical stream if there are no pending streams in |idle_streams_|.
   // Returns false, if it fails to open it.
   bool StreamOpened();
 
   // Called by AudioOutputProxy when the stream is started. If there
-  // are pending streams in |streams_| then it returns one of them,
+  // are pending streams in |idle_streams_| then it returns one of them,
   // otherwise creates a new one. Returns a physical stream that must
   // be used, or NULL if it fails to open audio device. Ownership of
   // the result is passed to the caller.
   AudioOutputStream* StreamStarted();
 
-  // Called by AudioOutputProxy when the stream is stopped. Returns
-  // |stream| to the pool of pending streams (i.e. |streams_|).
+  // Called by AudioOutputProxy when the stream is stopped.  Holds the
+  // stream temporarily in |pausing_streams_| and then |stream| is
+  // added to the pool of pending streams (i.e. |idle_streams_|).
   // Ownership of the |stream| is passed to the dispatcher.
   void StreamStopped(AudioOutputStream* stream);
 
@@ -68,14 +70,18 @@ class AudioOutputDispatcher
   friend class AudioOutputProxyTest;
 
   // Creates a new physical output stream, opens it and pushes to
-  // |streams_|.  Returns false if the stream couldn't be created or
+  // |idle_streams_|.  Returns false if the stream couldn't be created or
   // opened.
   bool CreateAndOpenStream();
 
   // A task scheduled by StreamStarted(). Opens a new stream and puts
-  // it in |streams_|.
+  // it in |idle_streams_|.
   void OpenTask();
 
+  // Before a stream is reused, it should sit idle for a bit.  This task is
+  // called once that time has elapsed.
+  void StopStreamTask();
+
   // Called by |close_timer_|. Closes all pending stream.
   void ClosePendingStreams();
 
@@ -83,8 +89,10 @@ class AudioOutputDispatcher
   MessageLoop* message_loop_;
   AudioParameters params_;
 
+  int64 pause_delay_milliseconds_;
   size_t paused_proxies_;
-  std::vector<AudioOutputStream*> streams_;
+  std::vector<AudioOutputStream*> idle_streams_;
+  std::list<AudioOutputStream*> pausing_streams_;
   base::DelayTimer<AudioOutputDispatcher> close_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputDispatcher);