WASAPI: Fix a potential deadlock with exclusive + duplex mode.

miniaudio.h

@@ -15254,13 +15254,6 @@ static ma_result ma_device_audio_thread__wasapi(ma_device* pDevice)
 
                 /* The process is to map the playback buffer and fill it as quickly as possible from input data. */
                 if (pMappedDeviceBufferPlayback == NULL) {
-                    /* WASAPI is weird with exclusive mode. You need to wait on the event _before_ querying the available frames. */
-                    if (pDevice->playback.shareMode == ma_share_mode_exclusive) {
-                        if (WaitForSingleObject(pDevice->wasapi.hEventPlayback, MA_WASAPI_WAIT_TIMEOUT_MILLISECONDS) != WAIT_OBJECT_0) {
-                            return MA_ERROR;   /* Wait failed. */
-                        }
-                    }
-
                     result = ma_device__get_available_frames__wasapi(pDevice, (ma_IAudioClient*)pDevice->wasapi.pAudioClientPlayback, &framesAvailablePlayback);
                     if (result != MA_SUCCESS) {
                         return result;
@@ -15276,18 +15269,6 @@ static ma_result ma_device_audio_thread__wasapi(ma_device* pDevice)
                         }
                     }
 
-                    /* If there's no frames available in the playback device we need to wait for more. */
-                    if (framesAvailablePlayback == 0) {
-                        /* In exclusive mode we waited at the top. */
-                        if (pDevice->playback.shareMode != ma_share_mode_exclusive) {
-                            if (WaitForSingleObject(pDevice->wasapi.hEventPlayback, MA_WASAPI_WAIT_TIMEOUT_MILLISECONDS) != WAIT_OBJECT_0) {
-                                return MA_ERROR;   /* Wait failed. */
-                            }
-                        }
-
-                        continue;
-                    }
-
                     /* We're ready to map the playback device's buffer. We don't release this until it's been entirely filled. */
                     hr = ma_IAudioRenderClient_GetBuffer((ma_IAudioRenderClient*)pDevice->wasapi.pRenderClient, framesAvailablePlayback, &pMappedDeviceBufferPlayback);
                     if (FAILED(hr)) {
@@ -15300,6 +15281,7 @@ static ma_result ma_device_audio_thread__wasapi(ma_device* pDevice)
                     mappedDeviceBufferFramesRemainingPlayback = framesAvailablePlayback;
                 }
 
+                if (mappedDeviceBufferFramesRemainingPlayback > 0) {
                     /* At this point we should have a buffer available for output. We need to keep writing input samples to it. */
                     for (;;) {
                         /* Try grabbing some captured data if we haven't already got a mapped buffer. */
@@ -15517,6 +15499,7 @@ static ma_result ma_device_audio_thread__wasapi(ma_device* pDevice)
                             break;
                         }
                     }
+                }
 
 
                 /* If at this point we've run out of data we need to release the buffer. */
@@ -15554,6 +15537,11 @@ static ma_result ma_device_audio_thread__wasapi(ma_device* pDevice)
                         c89atomic_exchange_8(&pDevice->wasapi.isStartedPlayback, MA_TRUE);
                     }
                 }
+
+                /* Make sure the device has started before waiting. */
+                if (WaitForSingleObject(pDevice->wasapi.hEventPlayback, MA_WASAPI_WAIT_TIMEOUT_MILLISECONDS) != WAIT_OBJECT_0) {
+                    return MA_ERROR;   /* Wait failed. */
+                }
             } break;