Refactor render and capture buffer notification flows to avoid more deadlocks

Author: mdias

RS_ASIO/RSAsioAudioCaptureClient.cpp

@@ -24,21 +24,23 @@ HRESULT STDMETHODCALLTYPE RSAsioAudioCaptureClient::GetBuffer(BYTE **ppData, UIN
 	// put the newest input data on the backbuffer
 	m_AsioAudioClient.SwapBuffers();
 
-	std::vector<BYTE>& buffer = m_AsioAudioClient.GetBackBuffer();
+	bool isDiscontinuity = true;
+	UINT64 backbufferTimestamp = 0;
+	BYTE* backbuffer = GetBackbufferIfPending(true, &backbufferTimestamp, &isDiscontinuity);
 
-	*ppData = buffer.data();
-	*pNumFramesToRead = m_NewBufferWaiting ? m_AsioAudioClient.GetBufferNumFrames() : 0;
+	*ppData = backbuffer;
+	*pNumFramesToRead = backbuffer ? m_AsioAudioClient.GetBufferNumFrames() : 0;
 
 	DWORD dwOutFlags = 0;
-	if (m_NewBufferPerfCounter == 0)
+	if (backbufferTimestamp == 0)
 	{
 		dwOutFlags |= AUDCLNT_BUFFERFLAGS_TIMESTAMP_ERROR;
 	}
-	if (!m_NewBufferWaiting)
+	if (!backbuffer)
 	{
 		dwOutFlags |= AUDCLNT_BUFFERFLAGS_SILENT;
 	}
-	if (m_DataDiscontinuityFlag)
+	if (isDiscontinuity)
 	{
 		dwOutFlags |= AUDCLNT_BUFFERFLAGS_DATA_DISCONTINUITY;
 	}
@@ -52,11 +54,10 @@ HRESULT STDMETHODCALLTYPE RSAsioAudioCaptureClient::GetBuffer(BYTE **ppData, UIN
 
 	if (pu64QPCPosition)
 	{
-		*pu64QPCPosition = m_NewBufferPerfCounter;
+		*pu64QPCPosition = backbufferTimestamp;
 	}
 
 	m_WaitingForBufferRelease = true;
-	m_NewBufferWaiting = false;
 
 	return S_OK;
 }
@@ -69,7 +70,6 @@ HRESULT STDMETHODCALLTYPE RSAsioAudioCaptureClient::ReleaseBuffer(UINT32 NumFram
 		return AUDCLNT_E_OUT_OF_ORDER;
 
 	m_WaitingForBufferRelease = false;
-	m_DataDiscontinuityFlag = false;
 
 	return S_OK;
 }

RS_ASIO/RSAsioAudioCaptureClient.h

@@ -15,4 +15,6 @@ class RSAsioAudioCaptureClient : public RSAsioAudioClientServiceBase<IAudioCaptu
 
 private:
 	bool m_WaitingForBufferRelease = false;
+
+	std::mutex m_mutex;
 };

RS_ASIO/RSAsioAudioClientServiceBase.cpp

@@ -20,7 +20,7 @@ RSAsioAudioClientServiceBase<TBaseClientService>::~RSAsioAudioClientServiceBase(
 template<typename TBaseClientService>
 void RSAsioAudioClientServiceBase<TBaseClientService>::NotifyNewBuffer()
 {
-	std::lock_guard<std::mutex> g(m_mutex);
+	std::lock_guard<std::mutex> g(m_bufferMutex);
 
 	LARGE_INTEGER li;
 
@@ -66,11 +66,46 @@ void RSAsioAudioClientServiceBase<TBaseClientService>::NotifyNewBuffer()
 template<typename TBaseClientService>
 bool RSAsioAudioClientServiceBase<TBaseClientService>::HasNewBufferWaiting() const
 {
-	std::lock_guard<std::mutex> g(m_mutex);
+	std::lock_guard<std::mutex> g(m_bufferMutex);
 
 	return m_NewBufferWaiting;
 }
 
+template<typename TBaseClientService>
+BYTE* RSAsioAudioClientServiceBase<TBaseClientService>::GetBackbufferIfPending(bool resetPendingFlag, UINT64* outOptionalPerfCounter, bool* outOptionalIsDiscontinuity)
+{
+	std::lock_guard<std::mutex> g(m_bufferMutex);
+	if (!m_NewBufferWaiting)
+	{
+		if (outOptionalPerfCounter)
+		{
+			*outOptionalPerfCounter = 0;
+		}
+		if (outOptionalIsDiscontinuity)
+		{
+			*outOptionalIsDiscontinuity = true;
+		}
+
+		return nullptr;
+	}
+
+	std::vector<BYTE>& buffer = m_AsioAudioClient.GetBackBuffer();
+	if (outOptionalPerfCounter)
+	{
+		*outOptionalPerfCounter = m_NewBufferPerfCounter;
+	}
+	if (outOptionalIsDiscontinuity)
+	{
+		*outOptionalIsDiscontinuity = m_DataDiscontinuityFlag;
+	}
+	if (resetPendingFlag)
+	{
+		m_NewBufferWaiting = false;
+		m_DataDiscontinuityFlag = false;
+	}
+	return buffer.data();
+}
+
 
 
 template class RSAsioAudioClientServiceBase<IAudioCaptureClient>;

RS_ASIO/RSAsioAudioClientServiceBase.h

@@ -18,13 +18,17 @@ class RSAsioAudioClientServiceBase : public ComBaseUnknown<TBaseClientService>
 
 protected:
 	RSAsioAudioClient& m_AsioAudioClient;
+
+	BYTE* GetBackbufferIfPending(bool resetPendingFlag, UINT64* outOptionalPerfCounter, bool* outOptionalIsDiscontinuity);
+
+private:
+	mutable std::mutex m_bufferMutex;
+
 	bool m_NewBufferWaiting; // set in ctor
 	UINT64 m_NewBufferPerfCounter = 0;
 
 	bool m_DataDiscontinuityFlag = false;
 
 	unsigned m_NumSequentialDiscontinuities = 0;
 	unsigned m_IgnoreDiscontinuityLoggingCountdown = 0;
-
-	mutable std::mutex m_mutex;
 };

RS_ASIO/RSAsioAudioRenderClient.cpp

@@ -21,19 +21,21 @@ HRESULT STDMETHODCALLTYPE RSAsioAudioRenderClient::GetBuffer(UINT32 NumFramesReq
 	if (m_WaitingForBufferRelease)
 		return AUDCLNT_E_OUT_OF_ORDER;
 
-	if (!m_NewBufferWaiting)
+	if (NumFramesRequested != m_AsioAudioClient.GetBufferNumFrames())
+		return AUDCLNT_E_BUFFER_SIZE_ERROR;
+
+	bool isDiscontinuity = true;
+	UINT64 backbufferTimestamp = 0;
+	BYTE* backbuffer = GetBackbufferIfPending(true, &backbufferTimestamp, &isDiscontinuity);
+
+	if (!backbuffer)
 	{
 		*ppData = nullptr;
 		return AUDCLNT_E_BUFFER_ERROR;
 	}
 
-	std::vector<BYTE>& buffer = m_AsioAudioClient.GetBackBuffer();
-	if (NumFramesRequested != m_AsioAudioClient.GetBufferNumFrames())
-		return AUDCLNT_E_BUFFER_SIZE_ERROR;
-
-	*ppData = buffer.data();
+	*ppData = backbuffer;
 	m_WaitingForBufferRelease = true;
-	m_NewBufferWaiting = false;
 
 	return S_OK;
 }
@@ -56,7 +58,6 @@ HRESULT STDMETHODCALLTYPE RSAsioAudioRenderClient::ReleaseBuffer(UINT32 NumFrame
 		return AUDCLNT_E_BUFFER_SIZE_ERROR;
 
 	m_WaitingForBufferRelease = false;
-	m_DataDiscontinuityFlag = false;
 
 	// move the data we've put in the backbuffer to the frontbuffer for output
 	m_AsioAudioClient.SwapBuffers();

RS_ASIO/RSAsioAudioRenderClient.h

@@ -14,4 +14,6 @@ class RSAsioAudioRenderClient : public RSAsioAudioClientServiceBase<IAudioRender
 
 private:
 	bool m_WaitingForBufferRelease = false;
+
+	std::mutex m_mutex;
 };