WASAPI: Suspend processing when AudioSessionStateInactive session event is received and restart on AudioSessionStateActive

modules/juce_audio_devices/native/juce_win32_WASAPI.cpp

@@ -352,8 +352,8 @@ void copyWavFormat (WAVEFORMATEXTENSIBLE& dest, const WAVEFORMATEX* src) noexcep
 class WASAPIDeviceBase
 {
 public:
-    WASAPIDeviceBase (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode, std::function<void()>&& cb)
-        : device (d), useExclusiveMode (exclusiveMode), reopenCallback (cb)
+    WASAPIDeviceBase (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode)
+        : device (d), useExclusiveMode (exclusiveMode)
     {
         clientEvent = CreateEvent (nullptr, false, false, nullptr);
 
@@ -429,7 +429,8 @@ public:
              && tryInitialisingWithBufferSize (bufferSizeSamples))
         {
             sampleRateHasChanged = false;
-            shouldClose = false;
+            shouldShutdown = false;
+
             channelMaps.clear();
 
             for (int i = 0; i <= channels.getHighestBit(); ++i)
@@ -468,9 +469,19 @@ public:
         sampleRateHasChanged = true;
     }
 
-    void deviceBecameInactive()
+    void deviceSessionBecameInactive()
     {
-        shouldClose = true;
+        isActive = false;
+    }
+
+    void deviceSessionExpired()
+    {
+        shouldShutdown = true;
+    }
+
+    void deviceSessionBecameActive()
+    {
+        isActive = true;
     }
 
     //==============================================================================
@@ -487,8 +498,7 @@ public:
     Array<int> channelMaps;
     UINT32 actualBufferSize = 0;
     int bytesPerSample = 0, bytesPerFrame = 0;
-    bool sampleRateHasChanged = false, shouldClose = false;
-    std::function<void()> reopenCallback;
+    std::atomic<bool> sampleRateHasChanged { false }, shouldShutdown { false }, isActive { true };
 
     virtual void updateFormat (bool isFloat) = 0;
 
@@ -504,13 +514,20 @@ private:
         JUCE_COMRESULT OnChannelVolumeChanged (DWORD, float*, DWORD, LPCGUID)  { return S_OK; }
         JUCE_COMRESULT OnGroupingParamChanged (LPCGUID, LPCGUID)               { return S_OK; }
 
-        JUCE_COMRESULT OnStateChanged(AudioSessionState state)
+        JUCE_COMRESULT OnStateChanged (AudioSessionState state)
         {
-            if (state == AudioSessionStateActive)
-                owner.reopenCallback();
-
-            if (state == AudioSessionStateInactive || state == AudioSessionStateExpired)
-                owner.deviceBecameInactive();
+            switch (state)
+            {
+            case AudioSessionStateInactive:
+                owner.deviceSessionBecameInactive();
+                break;
+            case AudioSessionStateExpired:
+                owner.deviceSessionExpired();
+                break;
+            case AudioSessionStateActive:
+                owner.deviceSessionBecameActive();
+                break;
+            }
 
             return S_OK;
         }
@@ -692,8 +709,8 @@ private:
 class WASAPIInputDevice  : public WASAPIDeviceBase
 {
 public:
-    WASAPIInputDevice (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode, std::function<void()>&& reopenCallback)
-        : WASAPIDeviceBase (d, exclusiveMode, std::move (reopenCallback))
+    WASAPIInputDevice (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode)
+        : WASAPIDeviceBase (d, exclusiveMode)
     {
     }
 
@@ -746,6 +763,8 @@ public:
             return false;
 
         purgeInputBuffers();
+        isActive = true;
+
         return true;
     }
 
@@ -853,8 +872,8 @@ private:
 class WASAPIOutputDevice  : public WASAPIDeviceBase
 {
 public:
-    WASAPIOutputDevice (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode, std::function<void()>&& reopenCallback)
-        : WASAPIDeviceBase (d, exclusiveMode, std::move (reopenCallback))
+    WASAPIOutputDevice (const ComSmartPtr<IMMDevice>& d, bool exclusiveMode)
+        : WASAPIDeviceBase (d, exclusiveMode)
     {
     }
 
@@ -899,7 +918,12 @@ public:
         if (check (renderClient->GetBuffer (samplesToDo, &outputData)))
             renderClient->ReleaseBuffer (samplesToDo, AUDCLNT_BUFFERFLAGS_SILENT);
 
-        return check (client->Start());
+        if (! check (client->Start()))
+            return false;
+
+        isActive = true;
+
+        return true;
     }
 
     int getNumSamplesAvailableToCopy() const
@@ -1124,7 +1148,8 @@ public:
         if (inputDevice != nullptr)   ResetEvent (inputDevice->clientEvent);
         if (outputDevice != nullptr)  ResetEvent (outputDevice->clientEvent);
 
-        deviceBecameInactive = false;
+        shouldShutdown = false;
+        deviceSampleRateChanged = false;
 
         startThread (8);
         Thread::sleep (5);
@@ -1233,7 +1258,6 @@ public:
         auto bufferSize        = currentBufferSizeSamples;
         auto numInputBuffers   = getActiveInputChannels().countNumberOfSetBits();
         auto numOutputBuffers  = getActiveOutputChannels().countNumberOfSetBits();
-        bool sampleRateHasChanged = false;
 
         AudioBuffer<float> ins  (jmax (1, numInputBuffers),  bufferSize + 32);
         AudioBuffer<float> outs (jmax (1, numOutputBuffers), bufferSize + 32);
@@ -1244,13 +1268,22 @@ public:
 
         while (! threadShouldExit())
         {
-            if ((outputDevice != nullptr && outputDevice->shouldClose)
-                || (inputDevice != nullptr && inputDevice->shouldClose))
+            if ((outputDevice != nullptr && outputDevice->shouldShutdown)
+                || (inputDevice != nullptr && inputDevice->shouldShutdown))
             {
-                deviceBecameInactive = true;
+                shouldShutdown = true;
+                triggerAsyncUpdate();
+
+                break;
             }
 
-            if (inputDevice != nullptr && ! deviceBecameInactive)
+            auto inputDeviceActive = (inputDevice != nullptr && inputDevice->isActive);
+            auto outputDeviceActive = (outputDevice != nullptr && outputDevice->isActive);
+
+            if (! inputDeviceActive && ! outputDeviceActive)
+                continue;
+
+            if (inputDeviceActive)
             {
                 if (outputDevice == nullptr)
                 {
@@ -1272,12 +1305,13 @@ public:
 
                 if (inputDevice->sampleRateHasChanged)
                 {
-                    sampleRateHasChanged = true;
-                    sampleRateChangedByOutput = false;
+                    deviceSampleRateChanged = true;
+                    triggerAsyncUpdate();
+
+                    break;
                 }
             }
 
-            if (! deviceBecameInactive)
             {
                 const ScopedTryLock sl (startStopLock);
 
@@ -1288,7 +1322,7 @@ public:
                     outs.clear();
             }
 
-            if (outputDevice != nullptr && ! deviceBecameInactive)
+            if (outputDeviceActive)
             {
                 // Note that this function is handed the input device so it can check for the event and make sure
                 // the input reservoir is filled up correctly even when bufferSize > device actualBufferSize
@@ -1296,15 +1330,11 @@ public:
 
                 if (outputDevice->sampleRateHasChanged)
                 {
-                    sampleRateHasChanged = true;
-                    sampleRateChangedByOutput = true;
-                }
-            }
+                    deviceSampleRateChanged = true;
+                    triggerAsyncUpdate();
 
-            if (sampleRateHasChanged || deviceBecameInactive)
-            {
-                triggerAsyncUpdate();
-                break; // Quit the thread... will restart it later!
+                    break;
+                }
             }
         }
     }
@@ -1332,7 +1362,7 @@ private:
     AudioIODeviceCallback* callback = {};
     CriticalSection startStopLock;
 
-    bool sampleRateChangedByOutput = false, deviceBecameInactive = false;
+    std::atomic<bool> shouldShutdown { false }, deviceSampleRateChanged { false };
 
     BigInteger lastKnownInputChannels, lastKnownOutputChannels;
 
@@ -1368,60 +1398,54 @@ private:
 
             auto flow = getDataFlow (device);
 
-            auto deviceReopenCallback = [this]
-            {
-                if (deviceBecameInactive)
-                {
-                    MessageManager::callAsync ([this]
-                    {
-                        close();
-                        reopenDevices();
-                    });
-                }
-            };
-
             if (deviceId == inputDeviceId && flow == eCapture)
-                inputDevice.reset (new WASAPIInputDevice (device, useExclusiveMode, deviceReopenCallback));
+                inputDevice.reset (new WASAPIInputDevice (device, useExclusiveMode));
             else if (deviceId == outputDeviceId && flow == eRender)
-                outputDevice.reset (new WASAPIOutputDevice (device, useExclusiveMode, deviceReopenCallback));
+                outputDevice.reset (new WASAPIOutputDevice (device, useExclusiveMode));
         }
 
         return (outputDeviceId.isEmpty() || (outputDevice != nullptr && outputDevice->isOk()))
              && (inputDeviceId.isEmpty() || (inputDevice != nullptr && inputDevice->isOk()));
     }
 
-    void reopenDevices()
-    {
-        outputDevice = nullptr;
-        inputDevice = nullptr;
-
-        initialise();
-
-        open (lastKnownInputChannels, lastKnownOutputChannels,
-              getChangedSampleRate(), currentBufferSizeSamples);
-
-        start (callback);
-    }
-
     //==============================================================================
     void handleAsyncUpdate() override
     {
-        stop();
+        auto closeDevices = [this]
+        {
+            close();
 
-        // sample rate change
-        if (! deviceBecameInactive)
-            reopenDevices();
-    }
+            outputDevice = nullptr;
+            inputDevice = nullptr;
+        };
 
-    double getChangedSampleRate() const
-    {
-        if (outputDevice != nullptr && sampleRateChangedByOutput)
-            return outputDevice->defaultSampleRate;
+        if (shouldShutdown)
+        {
+            closeDevices();
+        }
+        else if (deviceSampleRateChanged)
+        {
+            auto sampleRateChangedByInput = (inputDevice != nullptr && inputDevice->sampleRateHasChanged);
 
-        if (inputDevice != nullptr && ! sampleRateChangedByOutput)
-            return inputDevice->defaultSampleRate;
+            closeDevices();
+            initialise();
 
-        return 0.0;
+            auto changedSampleRate = [this, sampleRateChangedByInput] ()
+            {
+                if (inputDevice != nullptr && sampleRateChangedByInput)
+                    return inputDevice->defaultSampleRate;
+
+                if (outputDevice != nullptr && ! sampleRateChangedByInput)
+                    return outputDevice->defaultSampleRate;
+
+                return 0.0;
+            }();
+
+            open (lastKnownInputChannels, lastKnownOutputChannels,
+                  changedSampleRate, currentBufferSizeSamples);
+
+            start (callback);
+        }
     }
 
     //==============================================================================
@@ -1542,7 +1566,7 @@ private:
         HRESULT notify()
         {
             if (device != nullptr)
-            device->triggerAsyncDeviceChangeCallback();
+                device->triggerAsyncDeviceChangeCallback();
 
             return S_OK;
         }