Add xrun counter to device manager

modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp

@@ -731,6 +731,9 @@ void AudioDeviceManager::audioDeviceIOCallbackInt (const float** inputChannelDat
         const double msTaken = Time::getMillisecondCounterHiRes() - callbackStartTime;
         const double filterAmount = 0.2;
         cpuUsageMs += filterAmount * (msTaken - cpuUsageMs);
+
+        if (msTaken > msPerBlock)
+            xruns++;
     }
     else
     {
@@ -756,13 +759,14 @@ void AudioDeviceManager::audioDeviceIOCallbackInt (const float** inputChannelDat
 void AudioDeviceManager::audioDeviceAboutToStartInt (AudioIODevice* const device)
 {
     cpuUsageMs = 0;
+    xruns = 0;
 
     const double sampleRate = device->getCurrentSampleRate();
     const int blockSize = device->getCurrentBufferSizeSamples();
 
     if (sampleRate > 0.0 && blockSize > 0)
     {
-        const double msPerBlock = 1000.0 * blockSize / sampleRate;
+        msPerBlock = 1000.0 * blockSize / sampleRate;
         timeToCpuScale = (msPerBlock > 0.0) ? (1.0 / msPerBlock) : 0.0;
     }
 
@@ -779,6 +783,7 @@ void AudioDeviceManager::audioDeviceStoppedInt()
 {
     cpuUsageMs = 0;
     timeToCpuScale = 0;
+    xruns = 0;
     sendChangeMessage();
 
     const ScopedLock sl (audioCallbackLock);
@@ -998,6 +1003,12 @@ void AudioDeviceManager::playTestSound()
     }
 }
 
+int AudioDeviceManager::getXRunCount() const noexcept
+{
+    auto deviceXRuns = (currentAudioDevice != nullptr ? currentAudioDevice->getXRunCount() : -1);
+    return (deviceXRuns >= 0 ? deviceXRuns : xruns);
+}
+
 double AudioDeviceManager::getCurrentInputLevel() const noexcept    { return inputLevelMeter.getCurrentLevel(); }
 double AudioDeviceManager::getCurrentOutputLevel() const noexcept   { return outputLevelMeter.getCurrentLevel(); }
 

modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.h

@@ -436,6 +436,15 @@ public:
     */
     CriticalSection& getMidiCallbackLock() noexcept         { return midiCallbackLock; }
 
+    //==============================================================================
+    /** Returns the number of under- or over runs reported.
+
+        This method will use the underlying device's native getXRunCount if it supports
+        it. Otherwise it will estimate the number of under-/overruns by measuring the
+        time it spent in the audio callback.
+    */
+    int getXRunCount() const noexcept;
+
 private:
     //==============================================================================
     OwnedArray<AudioIODeviceType> availableDeviceTypes;
@@ -468,7 +477,8 @@ private:
     ScopedPointer<AudioSampleBuffer> testSound;
     int testSoundPosition;
 
-    double cpuUsageMs, timeToCpuScale;
+    double cpuUsageMs, timeToCpuScale, msPerBlock;
+    int xruns;
 
     struct LevelMeter
     {