WASAPI Driver: don't crash (or rather hang) when starting client fails

We were waiting infinitely for the WASAPI_Client_Started event, but when there was an error while starting the client, that event would never be signaled. So MuseScore would be stuck infinitely on launch.

src/framework/audio/internal/platform/win/wasapiaudioclient.cpp

@@ -29,8 +29,9 @@ using namespace winrt::Windows::Foundation;
 using namespace winrt::Windows::Media::Devices;
 using namespace winrt::Windows::Devices::Enumeration;
 
-WasapiAudioClient::WasapiAudioClient(HANDLE clientStartedEvent, HANDLE clientStoppedEvent)
-    : m_clientStartedEvent(clientStartedEvent), m_clientStoppedEvent(clientStoppedEvent)
+WasapiAudioClient::WasapiAudioClient(HANDLE clientStartedEvent, HANDLE clientFailedToStartEvent, HANDLE clientStoppedEvent)
+    : m_clientStartedEvent(clientStartedEvent), m_clientFailedToStartEvent(clientFailedToStartEvent), m_clientStoppedEvent(
+        clientStoppedEvent)
 {
     check_hresult(MFStartup(MF_VERSION, MFSTARTUP_LITE));
 }
@@ -218,6 +219,8 @@ HRESULT WasapiAudioClient::ActivateCompleted(IActivateAudioInterfaceAsyncOperati
         m_audioRenderClient = nullptr;
         m_sampleReadyAsyncResult = nullptr;
 
+        SetEvent(m_clientFailedToStartEvent);
+
         // Must return S_OK even on failure.
         return S_OK;
     }
@@ -370,6 +373,8 @@ void WasapiAudioClient::startPlayback() noexcept
     } catch (...) {
         hresult error = to_hresult();
         setStateAndNotify(DeviceState::Error, error);
+
+        SetEvent(m_clientFailedToStartEvent);
     }
 }
 
@@ -398,6 +403,9 @@ HRESULT WasapiAudioClient::onStartPlayback(IMFAsyncResult*) noexcept
         return S_OK;
     } catch (...) {
         setStateAndNotify(DeviceState::Error, to_hresult());
+
+        SetEvent(m_clientFailedToStartEvent);
+
         // Must return S_OK.
         return S_OK;
     }

src/framework/audio/internal/platform/win/wasapiaudioclient.h

@@ -29,7 +29,7 @@ namespace winrt {
 struct WasapiAudioClient : implements<WasapiAudioClient, IActivateAudioInterfaceCompletionHandler>
 {
 public:
-    WasapiAudioClient(HANDLE clientStartedEvent, HANDLE clientStoppedEvent);
+    WasapiAudioClient(HANDLE clientStartedEvent, HANDLE clientFailedToStartEvent, HANDLE clientStoppedEvent);
     ~WasapiAudioClient();
 
     void setHardWareOffload(bool value);
@@ -99,6 +99,7 @@ struct WasapiAudioClient : implements<WasapiAudioClient, IActivateAudioInterface
     DeviceState m_deviceState = DeviceState::Uninitialized;
     SampleRequestCallback m_sampleRequestCallback;
     HANDLE m_clientStartedEvent;
+    HANDLE m_clientFailedToStartEvent;
     HANDLE m_clientStoppedEvent;
 };
 }

src/framework/audio/internal/platform/win/wasapiaudiodriver.cpp

@@ -44,6 +44,7 @@ inline REFERENCE_TIME samplesToRefTime(int numSamples, double sampleRate) noexce
 
 struct WasapiData {
     HANDLE clientStartedEvent;
+    HANDLE clientFailedToStartEvent;
     HANDLE clientStoppedEvent;
 
     winrt::com_ptr<winrt::WasapiAudioClient> wasapiClient;
@@ -54,6 +55,7 @@ static WasapiData s_data;
 WasapiAudioDriver::WasapiAudioDriver()
 {
     s_data.clientStartedEvent = CreateEvent(NULL, FALSE, FALSE, L"WASAPI_Client_Started");
+    s_data.clientFailedToStartEvent = CreateEvent(NULL, FALSE, FALSE, L"WASAPI_Client_Failed_To_Start");
     s_data.clientStoppedEvent = CreateEvent(NULL, FALSE, FALSE, L"WASAPI_Client_Stopped");
 
     m_devicesListener.startWithCallback([this]() {
@@ -77,7 +79,8 @@ std::string WasapiAudioDriver::name() const
 bool WasapiAudioDriver::open(const Spec& spec, Spec* activeSpec)
 {
     if (!s_data.wasapiClient.get()) {
-        s_data.wasapiClient = make_self<WasapiAudioClient>(s_data.clientStartedEvent, s_data.clientStoppedEvent);
+        s_data.wasapiClient
+            = make_self<WasapiAudioClient>(s_data.clientStartedEvent, s_data.clientFailedToStartEvent, s_data.clientStoppedEvent);
     }
 
     m_desiredSpec = spec;
@@ -102,7 +105,15 @@ bool WasapiAudioDriver::open(const Spec& spec, Spec* activeSpec)
 
     s_data.wasapiClient->asyncInitializeAudioDevice(deviceId);
 
-    WaitForSingleObject(s_data.clientStartedEvent, INFINITE);
+    static constexpr DWORD handleCount = 2;
+    const HANDLE handles[handleCount] = { s_data.clientStartedEvent, s_data.clientFailedToStartEvent };
+
+    DWORD waitResult = WaitForMultipleObjects(handleCount, handles, false, INFINITE);
+    if (waitResult != WAIT_OBJECT_0) {
+        // Either the event was the second event (namely s_data.clientFailedToStartEvent)
+        // Or some wait error occurred
+        return false;
+    }
 
     m_activeSpec = m_desiredSpec;
     m_activeSpec.sampleRate = s_data.wasapiClient->sampleRate();