Bug 1045018 - Implement a thread safe singleton to allow setting kAudioHardwarePropertyRunLoop property to NULL only once. r=gcp

content/media/systemservices/OSXRunLoopSingleton.cpp

@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OSXRunLoopSingleton.h"
+#include <mozilla/StaticMutex.h>
+#include <mozilla/NullPtr.h>
+
+#include <AudioUnit/AudioUnit.h>
+#include <CoreAudio/AudioHardware.h>
+#include <CoreAudio/HostTime.h>
+#include <CoreFoundation/CoreFoundation.h>
+
+static bool gRunLoopSet = false;
+static mozilla::StaticMutex gMutex;
+
+void mozilla_set_coreaudio_notification_runloop_if_needed()
+{
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  if (gRunLoopSet) {
+    return;
+  }
+
+  /* This is needed so that AudioUnit listeners get called on this thread, and
+   * not the main thread. If we don't do that, they are not called, or a crash
+   * occur, depending on the OSX version. */
+  AudioObjectPropertyAddress runloop_address = {
+    kAudioHardwarePropertyRunLoop,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+  };
+
+  CFRunLoopRef run_loop = nullptr;
+
+  OSStatus r;
+  r = AudioObjectSetPropertyData(kAudioObjectSystemObject,
+                                 &runloop_address,
+                                 0, NULL, sizeof(CFRunLoopRef), &run_loop);
+  if (r != noErr) {
+    NS_WARNING("Could not make global CoreAudio notifications use their own thread.");
+  }
+
+  gRunLoopSet = true;
+}

content/media/systemservices/OSXRunLoopSingleton.h

@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OSXRUNLOOPSINGLETON_H_
+#define OSXRUNLOOPSINGLETON_H_
+
+#include <mozilla/Types.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/* This function tells CoreAudio to use its own thread for device change
+ * notifications, and can be called from any thread without external
+ * synchronization. */
+void MOZ_EXPORT
+mozilla_set_coreaudio_notification_runloop_if_needed();
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // OSXRUNLOOPSINGLETON_H_

content/media/systemservices/moz.build

@@ -25,6 +25,10 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('android', 'gonk'):
         'OpenSLESProvider.cpp',
     ]
 
+if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
+  UNIFIED_SOURCES += ['OSXRunLoopSingleton.cpp']
+  EXPORTS += ['OSXRunLoopSingleton.h']
+
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk':
     CXXFLAGS += [
         '-I%s/%s' % (CONFIG['ANDROID_SOURCE'], d) for d in [