Ports Portaudio WMME device timeout system to MacOsX CoreAudio in order to

avoid deadlock when a device is unplugged.
Vincent Lucas committed on Jan 10, 2013
2a20693 from https://github.com/jitsi/libsrc/commits/master/portaudio.zip

src/hostapi/coreaudio/pa_mac_core.c

@@ -2460,15 +2460,32 @@ static PaError StartStream( PaStream *s )
 
 // it's not clear from appl's docs that this really waits
 // until all data is flushed.
-static ComponentResult BlockWhileAudioUnitIsRunning( AudioUnit audioUnit, AudioUnitElement element )
+static ComponentResult BlockWhileAudioUnitIsRunning(
+        AudioUnit audioUnit,
+        AudioUnitElement element)
 {
+    long waitTime = 100;
+    // If PaUtil_GetRingBufferWriteAvailable starts repetitively and
+    // consecutively returning that there is no data available, do eventually
+    // give up in order to allow the caller to handle such cases. 
+    long totalTimeout = 0;
     Boolean isRunning = 1;
     while( isRunning ) {
        UInt32 s = sizeof( isRunning );
        ComponentResult err = AudioUnitGetProperty( audioUnit, kAudioOutputUnitProperty_IsRunning, kAudioUnitScope_Global, element,  &isRunning, &s );
        if( err )
           return err;
-       Pa_Sleep( 100 );
+       Pa_Sleep( waitTime );
+
+       // If a timeout is encountered, continue.  However, testing has
+       // shown that it is possible to unplug a device and to wait here
+       // forever. In order to allow the caller to handle such cases of
+       // repeated timeouts, do eventually given up. 
+       totalTimeout += waitTime; 
+       if( PA_COREAUDIO_MIN_TIMEOUT_MSEC_ <= totalTimeout) 
+       {
+           return paTimedOut;
+       } 
     }
     return noErr;
 }
@@ -2481,7 +2498,7 @@ static PaError StopStream( PaStream *s )
     VVDBUG(("StopStream()\n"));
 
     VDBUG( ("Waiting for BLIO.\n") );
-    waitUntilBlioWriteBufferIsFlushed( &stream->blio );
+    waitUntilBlioWriteBufferIsFlushed( &stream->blio);
     VDBUG( ( "Stopping stream.\n" ) );
 
     stream->state = STOPPING;
@@ -2507,7 +2524,7 @@ static PaError StopStream( PaStream *s )
        if( stream->outputUnit )
        {
           ERR_WRAP(AudioOutputUnitStop(stream->outputUnit));
-          ERR_WRAP( BlockWhileAudioUnitIsRunning(stream->outputUnit,0) );
+          ERR_WRAP( BlockWhileAudioUnitIsRunning(stream->outputUnit,0));
           ERR_WRAP(AudioUnitReset(stream->outputUnit,kAudioUnitScope_Global,0));
        }
     }

src/hostapi/coreaudio/pa_mac_core_blocking.c

@@ -415,6 +415,10 @@ PaError ReadStream( PaStream* stream,
     while( frames > 0 ) {
        long avail;
        long toRead;
+       // If PaUtil_GetRingBufferReadAvailable starts repetitively and
+       // consecutively returning that there is no data available, do eventually
+       // give up in order to allow the caller to handle such cases. 
+       long totalTimeout = 0;
        do {
           avail = PaUtil_GetRingBufferReadAvailable( &blio->inputRingBuffer );
 /*
@@ -438,6 +442,16 @@ PaError ReadStream( PaStream* stream,
                 return ret;
 #else
              Pa_Sleep( PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL );
+
+             // If a timeout is encountered, continue.  However, testing has
+             // shown that it is possible to unplug a device and to wait here
+             // forever. In order to allow the caller to handle such cases of
+             // repeated timeouts, do eventually given up. 
+             totalTimeout += PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL; 
+             if( PA_COREAUDIO_MAX_TIMEOUT_MSEC_ <= totalTimeout) 
+             {
+                 return paTimedOut;
+             } 
 #endif
           }
        } while( avail == 0 );
@@ -491,6 +505,10 @@ PaError WriteStream( PaStream* stream,
     while( frames > 0 ) {
        long avail = 0;
        long toWrite;
+       // If PaUtil_GetRingBufferWriteAvailable starts repetitively and
+       // consecutively returning that there is no data available, do eventually
+       // give up in order to allow the caller to handle such cases. 
+       long totalTimeout = 0;
 
        do {
           avail = PaUtil_GetRingBufferWriteAvailable( &blio->outputRingBuffer );
@@ -515,6 +533,16 @@ PaError WriteStream( PaStream* stream,
                 return ret;
 #else
              Pa_Sleep( PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL );
+
+             // If a timeout is encountered, continue.  However, testing has
+             // shown that it is possible to unplug a device and to wait here
+             // forever. In order to allow the caller to handle such cases of
+             // repeated timeouts, do eventually given up. 
+             totalTimeout += PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL; 
+             if( PA_COREAUDIO_MAX_TIMEOUT_MSEC_ <= totalTimeout) 
+             {
+                 return paTimedOut;
+             } 
 #endif
           }
        } while( avail == 0 );
@@ -561,13 +589,30 @@ PaError WriteStream( PaStream* stream,
 void waitUntilBlioWriteBufferIsFlushed( PaMacBlio *blio )
 {
     if( blio->outputRingBuffer.buffer ) {
+       // If PaUtil_GetRingBufferWriteAvailable starts repetitively and
+       // consecutively returning that there is no data available, do eventually
+       // give up in order to allow the caller to handle such cases. 
+       long totalTimeout = 0;
        long avail = PaUtil_GetRingBufferWriteAvailable( &blio->outputRingBuffer );
        while( avail != blio->outputRingBuffer.bufferSize ) {
           if( avail == 0 )
+          {
              Pa_Sleep( PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL );
+
+             // If a timeout is encountered, continue.  However, testing has
+             // shown that it is possible to unplug a device and to wait here
+             // forever. In order to allow the caller to handle such cases of
+             // repeated timeouts, do eventually given up. 
+             totalTimeout += PA_MAC_BLIO_BUSY_WAIT_SLEEP_INTERVAL; 
+             if( PA_COREAUDIO_MIN_TIMEOUT_MSEC_ <= totalTimeout) 
+             {
+                 return paTimedOut;
+             } 
+          }
           avail = PaUtil_GetRingBufferWriteAvailable( &blio->outputRingBuffer );
        }
     }
+    return paNoError;
 }
 
 

src/hostapi/coreaudio/pa_mac_core_blocking.h

@@ -76,6 +76,9 @@
 #define PA_MAC_BLIO_MUTEX
 */
 
+#define PA_COREAUDIO_MIN_TIMEOUT_MSEC_ (1000)
+#define PA_COREAUDIO_MAX_TIMEOUT_MSEC_ (2000)
+
 typedef struct {
     PaUtilRingBuffer inputRingBuffer;
     PaUtilRingBuffer outputRingBuffer;