Wait for the DS thread when stopping

The previous code would return from Pa_StopStream() when the streaming
thread signals that it is done. This is racy, because the streaming
thread is technically still running code by that point. If, for example,
the PortAudio user decides to unload the entire PortAudio DLL as soon as
Pa_StopStream() returns, hilarity could ensue.

Instead we can simply wait on the thread handle itself, which is both
safer and simpler.

Fixes PortAudio#926

src/hostapi/dsound/pa_win_ds.c

@@ -318,7 +318,6 @@ typedef struct PaWinDsStream
 #endif
     HANDLE           processingThread;
     PA_THREAD_ID     processingThreadId;
-    HANDLE           processingThreadCompleted;
 #endif
 
 } PaWinDsStream;
@@ -2092,16 +2091,6 @@ static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi,
         }
 #endif
 
-#ifndef PA_WIN_DS_USE_WMME_TIMER
-        stream->processingThreadCompleted = CreateEvent( NULL, /* bManualReset = */ TRUE, /* bInitialState = */ FALSE, NULL );
-        if( stream->processingThreadCompleted == NULL )
-        {
-            result = paUnanticipatedHostError;
-            PA_DS_SET_LAST_DIRECTSOUND_ERROR( GetLastError() );
-            goto error;
-        }
-#endif
-
         /* set up i/o parameters */
 
         if( userRequestedHostInputBufferSizeFrames > 0 || userRequestedHostOutputBufferSizeFrames > 0 )
@@ -2294,11 +2283,6 @@ static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi,
             CloseHandle( stream->waitableTimer );
 #endif
 
-#ifndef PA_WIN_DS_USE_WMME_TIMER
-        if( stream->processingThreadCompleted != NULL )
-            CloseHandle( stream->processingThreadCompleted );
-#endif
-
         if( stream->pDirectSoundOutputBuffer )
         {
             IDirectSoundBuffer_Stop( stream->pDirectSoundOutputBuffer );
@@ -2785,8 +2769,6 @@ PA_THREAD_FUNC ProcessingThreadProc( void *pArg )
     }
 #endif /* PA_WIN_DS_USE_WAITABLE_TIMER_OBJECT */
 
-    SetEvent( stream->processingThreadCompleted );
-
     return 0;
 }
 
@@ -2808,10 +2790,6 @@ static PaError CloseStream( PaStream* s )
         CloseHandle( stream->waitableTimer );
 #endif
 
-#ifndef PA_WIN_DS_USE_WMME_TIMER
-    CloseHandle( stream->processingThreadCompleted );
-#endif
-
     // Cleanup the sound buffers
     if( stream->pDirectSoundOutputBuffer )
     {
@@ -2906,10 +2884,6 @@ static PaError StartStream( PaStream *s )
 
     ResetEvent( stream->processingCompleted );
 
-#ifndef PA_WIN_DS_USE_WMME_TIMER
-    ResetEvent( stream->processingThreadCompleted );
-#endif
-
     if( stream->bufferProcessor.inputChannelCount > 0 )
     {
         // Start the buffer capture
@@ -3087,7 +3061,7 @@ static PaError StopStream( PaStream *s )
 #else
     if( stream->processingThread )
     {
-        if( WaitForSingleObject( stream->processingThreadCompleted, 30*100 ) == WAIT_TIMEOUT )
+        if( WaitForSingleObject( stream->processingThread, 30*100 ) == WAIT_TIMEOUT )
             return paUnanticipatedHostError;
 
         CLOSE_THREAD_HANDLE( stream->processingThread ); /* Delete thread. */