A few asio tweaks to avoid re-opening devices.

modules/juce_audio_devices/native/juce_win32_ASIO.cpp

@@ -323,10 +323,12 @@ public:
          optionalDllForDirectLoading (dllForDirectLoading),
          currentBitDepth (16),
          currentSampleRate (0),
+         currentCallback (nullptr),
          deviceIsOpen (false),
          isStarted (false),
          buffersCreated (false),
          postOutput (true),
+         needToReset (false),
          insideControlPanelModalLoop (false),
          shouldUsePreferredSize (false)
     {
@@ -336,8 +338,6 @@ public:
 
         jassert (currentASIODev [slotNumber] == nullptr);
         currentASIODev [slotNumber] = this;
-
-        openDevice();
     }
 
     ~ASIOAudioIODevice()
@@ -355,32 +355,37 @@ public:
     {
         // find a list of sample rates..
         const int possibleSampleRates[] = { 44100, 48000, 88200, 96000, 176400, 192000 };
-        sampleRates.clear();
+        Array<int> newRates;
 
         if (asioObject != nullptr)
         {
             for (int index = 0; index < numElementsInArray (possibleSampleRates); ++index)
-            {
-                const long err = asioObject->canSampleRate ((double) possibleSampleRates[index]);
-                JUCE_ASIO_LOG_ERROR ("canSampleRate " + String (possibleSampleRates[index]), err);
+                if (asioObject->canSampleRate ((double) possibleSampleRates[index]) == 0)
+                    newRates.add (possibleSampleRates[index]);
+        }
 
-                if (err == 0)
-                {
-                    sampleRates.add (possibleSampleRates[index]);
-                    JUCE_ASIO_LOG ("rate: " + String (possibleSampleRates[index]));
-                }
-            }
+        if (newRates.size() == 0)
+        {
+            double cr = 0;
+            const long err = asioObject->getSampleRate (&cr);
+            JUCE_ASIO_LOG ("No sample rates supported - current rate: " + String ((int) cr));
+            JUCE_ASIO_LOG_ERROR ("getSampleRate", err);
 
-            if (sampleRates.size() == 0)
-            {
-                double cr = 0;
-                const long err = asioObject->getSampleRate (&cr);
-                JUCE_ASIO_LOG ("No sample rates supported - current rate: " + String ((int) cr));
-                JUCE_ASIO_LOG_ERROR ("getSampleRate", err);
+            if (err == 0)
+                newRates.add ((int) cr);
+        }
 
-                if (err == 0)
-                    sampleRates.add ((int) cr);
-            }
+        if (sampleRates != newRates)
+        {
+            sampleRates.swapWithArray (newRates);
+
+           #if JUCE_ASIO_DEBUGGING
+            StringArray s;
+            for (int i = 0; i < sampleRates.size(); ++i)
+                s.add (String (sampleRates.getUnchecked(i)));
+
+            JUCE_ASIO_LOG ("Rates: " + s.joinIntoString (" "));
+           #endif
         }
     }
 
@@ -400,7 +405,7 @@ public:
                  int bufferSizeSamples)
     {
         close();
-        currentCallback = nullptr;
+        jassert (currentCallback == nullptr);
 
         if (bufferSizeSamples <= 0)
             shouldUsePreferredSize = true;
@@ -813,7 +818,6 @@ public:
         {
             stopTimer();
 
-            // used to cause a reset
             JUCE_ASIO_LOG ("restart request!");
 
             AudioIODeviceCallback* const oldCallback = currentCallback;
@@ -1090,7 +1094,7 @@ private:
                     if ((err = asioObject->getBufferSize (&minSize, &maxSize, &preferredSize, &granularity)) == 0)
                     {
                         // find a list of buffer sizes..
-                        JUCE_ASIO_LOG (String ((int) minSize) + " " + String ((int) maxSize) + " " + String ((int) preferredSize) + " " + String ((int) granularity));
+                        JUCE_ASIO_LOG (String ((int) minSize) + "->" + String ((int) maxSize) + ", " + String ((int) preferredSize) + ", " + String ((int) granularity));
 
                         if (granularity >= 0)
                         {
@@ -1216,7 +1220,7 @@ private:
                         // ignore an error here, as it might start later after setting other stuff up
                         JUCE_ASIO_LOG_ERROR ("start", err);
 
-                        Thread::sleep (100);
+                        Thread::sleep (80);
                         asioObject->stop();
                     }
                     else
@@ -1250,6 +1254,7 @@ private:
 
         deviceIsOpen = false;
         needToReset = false;
+        stopTimer();
         return error;
     }
 
@@ -1365,27 +1370,16 @@ private:
         switch (selector)
         {
         case kAsioSelectorSupported:
-            if (value == kAsioResetRequest
-                || value == kAsioEngineVersion
-                || value == kAsioResyncRequest
-                || value == kAsioLatenciesChanged
-                || value == kAsioSupportsInputMonitor)
+            if (value == kAsioResetRequest || value == kAsioEngineVersion || value == kAsioResyncRequest
+                 || value == kAsioLatenciesChanged || value == kAsioSupportsInputMonitor)
                 return 1;
             break;
 
-        case kAsioBufferSizeChange:
-        case kAsioResetRequest:
-        case kAsioResyncRequest:
-            if (currentASIODev[deviceIndex] != nullptr)
-                currentASIODev[deviceIndex]->resetRequest();
-
-            return 1;
-
-        case kAsioLatenciesChanged:
-            return 1;
-
-        case kAsioEngineVersion:
-            return 2;
+        case kAsioBufferSizeChange: JUCE_ASIO_LOG ("kAsioBufferSizeChange"); return sendResetRequest (deviceIndex);
+        case kAsioResetRequest:     JUCE_ASIO_LOG ("kAsioResetRequest");     return sendResetRequest (deviceIndex);
+        case kAsioResyncRequest:    JUCE_ASIO_LOG ("kAsioResyncRequest");    return sendResetRequest (deviceIndex);
+        case kAsioLatenciesChanged: JUCE_ASIO_LOG ("kAsioLatenciesChanged"); return 1;
+        case kAsioEngineVersion:    return 2;
 
         case kAsioSupportsTimeInfo:
         case kAsioSupportsTimeCode:
@@ -1395,6 +1389,14 @@ private:
         return 0;
     }
 
+    static long sendResetRequest (int deviceIndex)
+    {
+        if (currentASIODev[deviceIndex] != nullptr)
+            currentASIODev[deviceIndex]->resetRequest();
+
+        return 1;
+    }
+
     static void JUCE_ASIOCALLBACK sampleRateChangedCallback (ASIOSampleRate)
     {
     }