Create a utility for audio initialization.

The audio initialization on ios can happen on both UI and IO threads. Creating an audio session utility that prevents a potential race condition.

R=scherkus@chromium.org

BUG=None


Review URL: https://chromiumcodereview.appspot.com/11505005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@173816 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 61 insertions, 30 deletions

diff --git a/media/audio/ios/audio_manager_ios.h b/media/audio/ios/audio_manager_ios.h
index 55cbe6e..34a85fc 100644
--- a/media/audio/ios/audio_manager_ios.h
+++ b/media/audio/ios/audio_manager_ios.h
@@ -42,11 +42,6 @@ class MEDIA_EXPORT AudioManagerIOS : public AudioManagerBase {
   virtual ~AudioManagerIOS();
 
  private:
-  // Initializes the audio session if necessary. Safe to call multiple times.
-  // Returns a bool indicating whether the audio session has been successfully
-  // initialized (either in the current call or in a previous call).
-  bool InitAudioSession();
-
   DISALLOW_COPY_AND_ASSIGN(AudioManagerIOS);
 };
 
diff --git a/media/audio/ios/audio_manager_ios.mm b/media/audio/ios/audio_manager_ios.mm
index a4ffff5..8949b1c 100644
--- a/media/audio/ios/audio_manager_ios.mm
+++ b/media/audio/ios/audio_manager_ios.mm
@@ -9,6 +9,7 @@
 
 #include "base/sys_info.h"
 #include "media/audio/fake_audio_input_stream.h"
+#include "media/audio/ios/audio_session_util_ios.h"
 #include "media/audio/mac/audio_input_mac.h"
 #include "media/base/limits.h"
 
@@ -16,21 +17,6 @@ namespace media {
 
 enum { kMaxInputChannels = 2 };
 
-// Initializes the audio session, returning a bool indicating whether
-// initialization was successful. Should only be called once.
-static bool InitAudioSessionInternal() {
-  OSStatus error = AudioSessionInitialize(NULL, NULL, NULL, NULL);
-  DCHECK(error != kAudioSessionAlreadyInitialized);
-  AVAudioSession* audioSession = [AVAudioSession sharedInstance];
-  BOOL result = [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord
-                                    error:nil];
-  DCHECK(result);
-  UInt32 allowMixing = true;
-  AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers,
-                          sizeof(allowMixing), &allowMixing);
-  return error == kAudioSessionNoError;
-}
-
 AudioManagerIOS::AudioManagerIOS() {
 }
 
@@ -43,7 +29,7 @@ bool AudioManagerIOS::HasAudioOutputDevices() {
 }
 
 bool AudioManagerIOS::HasAudioInputDevices() {
-  if (!InitAudioSession())
+  if (!InitAudioSessionIOS())
     return false;
   // Note that the |kAudioSessionProperty_AudioInputAvailable| property is a
   // 32-bit integer, not a boolean.
@@ -114,11 +100,6 @@ void AudioManagerIOS::ReleaseInputStream(AudioInputStream* stream) {
   delete stream;
 }
 
-bool AudioManagerIOS::InitAudioSession() {
-  static const bool kSessionInitialized = InitAudioSessionInternal();
-  return kSessionInitialized;
-}
-
 // static
 AudioManager* CreateAudioManager() {
   return new AudioManagerIOS();
diff --git a/media/audio/ios/audio_session_util_ios.h b/media/audio/ios/audio_session_util_ios.h
new file mode 100644
index 0000000..175db91
--- /dev/null
+++ b/media/audio/ios/audio_session_util_ios.h
@@ -0,0 +1,17 @@
+// Copyright 2012 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.
+
+#ifndef MEDIA_AUDIO_IOS_AUDIO_SESSION_UTIL_IOS_H_
+#define MEDIA_AUDIO_IOS_AUDIO_SESSION_UTIL_IOS_H_
+
+namespace media {
+
+// Initializes and configures the audio session, returning a bool indicating
+// whether initialization was successful. Can be called multiple times.
+// Safe to call from any thread.
+bool InitAudioSessionIOS();
+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_IOS_AUDIO_SESSION_UTIL_IOS_H_
diff --git a/media/audio/ios/audio_session_util_ios.mm b/media/audio/ios/audio_session_util_ios.mm
new file mode 100644
index 0000000..3d75546a
--- /dev/null
+++ b/media/audio/ios/audio_session_util_ios.mm
@@ -0,0 +1,35 @@
+// Copyright 2012 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/ios/audio_session_util_ios.h"
+
+#include <AVFoundation/AVFoundation.h>
+
+#include "base/logging.h"
+
+namespace media {
+
+bool InitAudioSessionIOS() {
+  static bool kSessionInitialized = false;
+  static dispatch_once_t once = 0;
+  dispatch_once(&once, ^{
+      OSStatus error = AudioSessionInitialize(NULL, NULL, NULL, NULL);
+      if (error != kAudioSessionNoError)
+        DLOG(ERROR) << "AudioSessionInitialize OSStatus error: " << error;
+      BOOL result = [[AVAudioSession sharedInstance]
+          setCategory:AVAudioSessionCategoryPlayAndRecord
+                error:nil];
+      if (!result)
+        DLOG(ERROR) << "AVAudioSession setCategory failed";
+      UInt32 allowMixing = true;
+      AudioSessionSetProperty(
+          kAudioSessionProperty_OverrideCategoryMixWithOthers,
+          sizeof(allowMixing), &allowMixing);
+      // Speech input cannot be used if either of these two conditions fail.
+      kSessionInitialized = (error == kAudioSessionNoError) && result;
+  });
+  return kSessionInitialized;
+}
+
+}  // namespace media
diff --git a/media/media.gyp b/media/media.gyp
index 59d48ec..6d20998 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -95,6 +95,8 @@
         'audio/fake_audio_output_stream.h',
         'audio/ios/audio_manager_ios.h',
         'audio/ios/audio_manager_ios.mm',
+        'audio/ios/audio_session_util_ios.h',
+        'audio/ios/audio_session_util_ios.mm',
         'audio/linux/alsa_input.cc',
         'audio/linux/alsa_input.h',
         'audio/linux/alsa_output.cc',
@@ -425,20 +427,21 @@
             '<@(shared_memory_support_sources)',
           ],
           'sources/': [
+            # Exclude everything but iOS-specific files.
+            ['exclude', '\\.(cc|mm)$'],
+            ['include', '_ios\\.(cc|mm)$'],
+            ['include', '(^|/)ios/'],
+            # Re-include specific pieces.
             # iOS support is limited to audio input only.
-            ['exclude', '.*'],
             ['include', '^audio/audio_buffers_state\\.'],
             ['include', '^audio/audio_input_controller\\.'],
-            ['include', '^audio/audio_io\\.h$'],
             ['include', '^audio/audio_manager\\.'],
             ['include', '^audio/audio_manager_base\\.'],
             ['include', '^audio/audio_parameters\\.'],
             ['include', '^audio/fake_audio_input_stream\\.'],
             ['include', '^audio/fake_audio_output_stream\\.'],
-            ['include', '^audio/ios/audio_manager_ios\\.'],
             ['include', '^base/audio_bus\\.'],
             ['include', '^base/channel_layout\\.'],
-            ['include', '^base/media\\.h$'],
             ['include', '^base/media_stub\\.cc$'],
           ],
           'link_settings': {