CoreAudio: Call AudioDeviceStop() on IO thread when stopping audio de…

…vices

When AudioDeviceStop() is called from a thread other than the IO thread there are no guarantees about the IOProc being called before the thread actually terminates. Moving this call to the audioCallback() method ensures that the device will be stopped immediately and we can remove a check that was taking a few seconds to close devices.

modules/juce_audio_devices/native/juce_mac_CoreAudio.cpp

@@ -671,6 +671,8 @@ class CoreAudioInternal  : private Timer
 
     bool start()
     {
+        const ScopedLock sl (callbackLock);
+
         if (! started)
         {
             callback = nullptr;
@@ -703,41 +705,27 @@ class CoreAudioInternal  : private Timer
 
     void stop (bool leaveInterruptRunning)
     {
-        {
-            const ScopedLock sl (callbackLock);
-            callback = nullptr;
-        }
+        const ScopedLock sl (callbackLock);
+
+        callback = nullptr;
 
         if (started && (deviceID != 0) && ! leaveInterruptRunning)
         {
-            OK (AudioDeviceStop (deviceID, audioProcID));
-            OK (AudioDeviceDestroyIOProcID (deviceID, audioProcID));
-            audioProcID = {};
-
-            started = false;
+            audioDeviceStopPending = true;
 
-            { const ScopedLock sl (callbackLock); }
-
-            // wait until it's definitely stopped calling back..
+            // wait until AudioDeviceStop() has been called on the IO thread
             for (int i = 40; --i >= 0;)
             {
-                Thread::sleep (50);
-
-                UInt32 running = 0;
-                UInt32 size = sizeof (running);
-
-                AudioObjectPropertyAddress pa;
-                pa.mSelector = kAudioDevicePropertyDeviceIsRunning;
-                pa.mScope = kAudioObjectPropertyScopeWildcard;
-                pa.mElement = juceAudioObjectPropertyElementMain;
-
-                OK (AudioObjectGetPropertyData (deviceID, &pa, 0, nullptr, &size, &running));
-
-                if (running == 0)
+                if (audioDeviceStopPending == false)
                     break;
+
+                const ScopedUnlock ul (callbackLock);
+                Thread::sleep (50);
             }
 
-            const ScopedLock sl (callbackLock);
+            OK (AudioDeviceDestroyIOProcID (deviceID, audioProcID));
+            audioProcID = {};
+            started = false;
         }
     }
 
@@ -749,6 +737,14 @@ class CoreAudioInternal  : private Timer
     {
         const ScopedLock sl (callbackLock);
 
+        if (audioDeviceStopPending)
+        {
+            if (OK (AudioDeviceStop (deviceID, audioProcID)))
+                audioDeviceStopPending = false;
+
+            return;
+        }
+
         if (callback != nullptr)
         {
             for (int i = numInputChans; --i >= 0;)
@@ -836,7 +832,7 @@ class CoreAudioInternal  : private Timer
 private:
     CriticalSection callbackLock;
     AudioDeviceID deviceID;
-    bool started = false;
+    bool started = false, audioDeviceStopPending = false;
     double sampleRate = 0;
     int bufferSize = 512;
     HeapBlock<float> audioBuffer;