Fixed a bug where the AU/AUv3 wrapper would create a spurious input bus when no inputs where specified in the Projucer's legacy channel configuration field

modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm

@@ -117,7 +117,9 @@ class JuceAU   : public AudioProcessorHolder,
 public:
     JuceAU (AudioUnit component)
         : AudioProcessorHolder(activePlugins.size() + activeUIs.size() == 0),
-          MusicDeviceBase (component, (UInt32) juceFilter->getBusCount (true), (UInt32) juceFilter->getBusCount (false)),
+          MusicDeviceBase (component,
+                           (UInt32) AudioUnitHelpers::getBusCount (juceFilter, true),
+                           (UInt32) AudioUnitHelpers::getBusCount (juceFilter, false)),
           isBypassed (false),
           mapper (*juceFilter)
     {
@@ -189,7 +191,7 @@ public:
             return err;
 
         mapper.alloc();
-        pulledSucceeded.calloc (static_cast<size_t> (juceFilter->getBusCount (true)));
+        pulledSucceeded.calloc (static_cast<size_t> (AudioUnitHelpers::getBusCount (juceFilter, true)));
 
         prepareToPlay();
 
@@ -263,6 +265,11 @@ public:
     //==============================================================================
     bool BusCountWritable (AudioUnitScope scope) override
     {
+       #ifdef JucePlugin_PreferredChannelConfigurations
+        ignoreUnused (scope);
+
+        return false;
+       #else
         bool isInput;
 
         if (scopeToDirection (scope, isInput) != noErr)
@@ -274,8 +281,9 @@ public:
         if (isInput) return false;
        #endif
 
-        const int busCount = juceFilter->getBusCount (isInput);
+        const int busCount = AudioUnitHelpers::getBusCount (juceFilter, isInput);
         return (juceFilter->canAddBus (isInput) || (busCount > 0 && juceFilter->canRemoveBus (isInput)));
+       #endif
     }
 
     OSStatus SetBusCount (AudioUnitScope scope, UInt32 count) override
@@ -286,9 +294,12 @@ public:
         if ((err = scopeToDirection (scope, isInput)) != noErr)
             return err;
 
-        if (count != (UInt32) juceFilter->getBusCount (isInput))
+        if (count != (UInt32) AudioUnitHelpers::getBusCount (juceFilter, isInput))
         {
-            const int busCount = juceFilter->getBusCount (isInput);
+           #ifdef JucePlugin_PreferredChannelConfigurations
+            return kAudioUnitErr_PropertyNotWritable;
+           #else
+            const int busCount = AudioUnitHelpers::getBusCount (juceFilter, isInput);
 
             if  ((! juceFilter->canAddBus (isInput)) && ((busCount == 0) || (! juceFilter->canRemoveBus (isInput))))
                 return kAudioUnitErr_PropertyNotWritable;
@@ -328,7 +339,7 @@ public:
             if (err != noErr)
             {
                 // restore bus state
-                const int newBusCount = juceFilter->getBusCount (isInput);
+                const int newBusCount = AudioUnitHelpers::getBusCount (juceFilter, isInput);
                 for (int i = newBusCount; i != busCount; i += (busCount > newBusCount ? 1 : -1))
                 {
                     if (busCount > newBusCount)
@@ -346,6 +357,7 @@ public:
 
             if (err != noErr)
                 return err;
+           #endif
         }
 
         return noErr;
@@ -862,7 +874,7 @@ public:
     ComponentResult Version() override                   { return JucePlugin_VersionCode; }
     bool SupportsTail() override                         { return true; }
     Float64 GetTailTime() override                       { return juceFilter->getTailLengthSeconds(); }
-    double getSampleRate()                               { return juceFilter->getBusCount (false) > 0 ? GetOutput(0)->GetStreamFormat().mSampleRate : 44100.0; }
+    double getSampleRate()                               { return AudioUnitHelpers::getBusCount (juceFilter, false) > 0 ? GetOutput(0)->GetStreamFormat().mSampleRate : 44100.0; }
 
     Float64 GetLatency() override
     {
@@ -1652,7 +1664,7 @@ private:
         busIdx = static_cast<int> (element);
 
         if ((err = scopeToDirection (scope, isInput)) != noErr) return err;
-        if (isPositiveAndBelow (busIdx, juceFilter->getBusCount (isInput))) return noErr;
+        if (isPositiveAndBelow (busIdx, AudioUnitHelpers::getBusCount (juceFilter, isInput))) return noErr;
 
         return kAudioUnitErr_InvalidElement;
     }
@@ -1736,8 +1748,8 @@ private:
     OSStatus syncAudioUnitWithProcessor()
     {
         OSStatus err = noErr;
-        const int enabledInputs  = juceFilter->getBusCount (true);
-        const int enabledOutputs = juceFilter->getBusCount (false);
+        const int enabledInputs  = AudioUnitHelpers::getBusCount (juceFilter, true);
+        const int enabledOutputs = AudioUnitHelpers::getBusCount (juceFilter, false);
 
         if ((err =  MusicDeviceBase::SetBusCount (kAudioUnitScope_Input,  static_cast<UInt32> (enabledInputs))) != noErr)
             return err;
@@ -1758,8 +1770,8 @@ private:
 
     OSStatus syncProcessorWithAudioUnit()
     {
-        const int numInputBuses  = juceFilter->getBusCount (true);
-        const int numOutputBuses = juceFilter->getBusCount (false);
+        const int numInputBuses  = AudioUnitHelpers::getBusCount (juceFilter, true);
+        const int numOutputBuses = AudioUnitHelpers::getBusCount (juceFilter, false);
 
         const int numInputElements  = static_cast<int> (GetScope(kAudioUnitScope_Input). GetNumberOfElements());
         const int numOutputElements = static_cast<int> (GetScope(kAudioUnitScope_Output).GetNumberOfElements());
@@ -1794,7 +1806,7 @@ private:
             return kAudioUnitErr_FormatNotSupported;
        #endif
 
-        if (! juceFilter->setBusesLayout (requestedLayouts))
+        if (! AudioUnitHelpers::setBusesLayout (juceFilter, requestedLayouts))
             return kAudioUnitErr_FormatNotSupported;
 
         // update total channel count
@@ -1898,7 +1910,7 @@ private:
         Array<Array<AudioChannelLayoutTag> >& layouts = isInput ? supportedInputLayouts : supportedOutputLayouts;
         layouts.clear();
 
-        const int numBuses = juceFilter->getBusCount (isInput);
+        const int numBuses = AudioUnitHelpers::getBusCount (juceFilter, isInput);
         for (int busNr = 0; busNr < numBuses; ++busNr)
         {
             Array<AudioChannelLayoutTag> busLayouts;
@@ -1912,8 +1924,8 @@ private:
     {
         currentInputLayout.clear(); currentOutputLayout.clear();
 
-        currentInputLayout. resize (juceFilter->getBusCount (true));
-        currentOutputLayout.resize (juceFilter->getBusCount (false));
+        currentInputLayout. resize (AudioUnitHelpers::getBusCount (juceFilter, true));
+        currentOutputLayout.resize (AudioUnitHelpers::getBusCount (juceFilter, false));
 
         addSupportedLayoutTagsForDirection (true);
         addSupportedLayoutTagsForDirection (false);

modules/juce_audio_plugin_client/AU/juce_AUv3_Wrapper.mm

@@ -542,7 +542,7 @@ public:
         for (int dir = 0; dir < 2; ++dir)
         {
             const bool isInput = (dir == 0);
-            const int n = processor.getBusCount (isInput);
+            const int n = AudioUnitHelpers::getBusCount (&processor, isInput);
             Array<AudioChannelSet>& channelSets = (isInput ? layouts.inputBuses : layouts.outputBuses);
 
             AUAudioUnitBusArray* auBuses = (isInput ? [getAudioUnit() inputBusses] : [getAudioUnit() outputBusses]);
@@ -578,7 +578,7 @@ public:
         }
        #endif
 
-        if (! processor.setBusesLayout (layouts))
+        if (! AudioUnitHelpers::setBusesLayout (&getAudioProcessor(), layouts))
         {
             if (outError != nullptr)
                 *outError = [NSError errorWithDomain:NSOSStatusErrorDomain code:kAudioUnitErr_FormatNotSupported userInfo:nullptr];
@@ -596,7 +596,7 @@ public:
 
         audioBuffer.prepare (totalInChannels, totalOutChannels, static_cast<int> (maxFrames));
 
-        double sampleRate = (jmax (processor.getBusCount (true), processor.getBusCount (false)) > 0 ?
+        double sampleRate = (jmax (AudioUnitHelpers::getBusCount (&processor, true), AudioUnitHelpers::getBusCount (&processor, false)) > 0 ?
                              [[[([inputBusses count] > 0 ? inputBusses : outputBusses) objectAtIndexedSubscript: 0] format] sampleRate] : 44100.0);
 
         processor.setRateAndBufferSizeDetails (sampleRate, static_cast<int> (maxFrames));
@@ -869,7 +869,7 @@ private:
     {
         ScopedPointer<NSMutableArray<AUAudioUnitBus*> > array = [[NSMutableArray<AUAudioUnitBus*> alloc] init];
         AudioProcessor& processor = getAudioProcessor();
-        const int n = processor.getBusCount (isInput);
+        const int n = AudioUnitHelpers::getBusCount (&processor, isInput);
 
         for (int i = 0; i < n; ++i)
         {
@@ -996,7 +996,7 @@ private:
         OwnedArray<BusBuffer>& busBuffers = isInput ? inBusBuffers : outBusBuffers;
         busBuffers.clear();
 
-        const int n = getAudioProcessor().getBusCount (isInput);
+        const int n = AudioUnitHelpers::getBusCount (&getAudioProcessor(), isInput);
         const AUAudioFrameCount maxFrames = [getAudioUnit() maximumFramesToRender];
 
         for (int busIdx = 0; busIdx < n; ++busIdx)

modules/juce_audio_processors/format_types/juce_AU_Shared.h

@@ -324,8 +324,8 @@ struct AudioUnitHelpers
 
         void alloc()
         {
-            const int numInputBuses  = processor.getBusCount (true);
-            const int numOutputBuses = processor.getBusCount (false);
+            const int numInputBuses  = AudioUnitHelpers::getBusCount (&processor, true);
+            const int numOutputBuses = AudioUnitHelpers::getBusCount (&processor, false);
 
             initializeChannelMapArray (true, numInputBuses);
             initializeChannelMapArray (false, numOutputBuses);
@@ -611,10 +611,10 @@ struct AudioUnitHelpers
     {
         Array<AUChannelInfo> channelInfo;
 
-        const bool hasMainInputBus  = (processor.getBusCount (true)  > 0);
-        const bool hasMainOutputBus = (processor.getBusCount (false) > 0);
+        const bool hasMainInputBus  = (AudioUnitHelpers::getBusCount (&processor, true)  > 0);
+        const bool hasMainOutputBus = (AudioUnitHelpers::getBusCount (&processor, false) > 0);
 
-        if ((! hasMainInputBus)  && (! hasMainOutputBus))
+        if ((! hasMainInputBus) && (! hasMainOutputBus))
         {
             // midi effect plug-in: no audio
             AUChannelInfo info;
@@ -743,6 +743,73 @@ struct AudioUnitHelpers
 
         return channelInfo;
     }
+
+    //==============================================================================
+    static int getBusCount (const AudioProcessor* juceFilter, bool isInput)
+    {
+        int busCount = juceFilter->getBusCount (isInput);
+
+       #ifdef JucePlugin_PreferredChannelConfigurations
+        short configs[][2] = {JucePlugin_PreferredChannelConfigurations};
+        const int numConfigs = sizeof (configs) / sizeof (short[2]);
+
+        bool hasOnlyZeroChannels = true;
+
+        for (int i = 0; i < numConfigs && hasOnlyZeroChannels == true; ++i)
+            if (configs[i][isInput ? 0 : 1] != 0)
+                hasOnlyZeroChannels = false;
+
+        busCount = jmin (busCount, hasOnlyZeroChannels ? 0 : 1);
+       #endif
+
+        return busCount;
+    }
+
+    static bool setBusesLayout (AudioProcessor* juceFilter, const AudioProcessor::BusesLayout& requestedLayouts)
+    {
+       #ifdef JucePlugin_PreferredChannelConfigurations
+        AudioProcessor::BusesLayout copy (requestedLayouts);
+
+        for (int dir = 0; dir < 2; ++dir)
+        {
+            const bool isInput = (dir == 0);
+
+            const int actualBuses = juceFilter->getBusCount (isInput);
+            const int auNumBuses  = getBusCount (juceFilter, isInput);
+            Array<AudioChannelSet>& buses = (isInput ? copy.inputBuses : copy.outputBuses);
+
+            for (int i = auNumBuses; i < actualBuses; ++i)
+                buses.add (AudioChannelSet::disabled());
+        }
+
+        return juceFilter->setBusesLayout (copy);
+       #else
+        return juceFilter->setBusesLayout (requestedLayouts);
+       #endif
+    }
+
+    static AudioProcessor::BusesLayout getBusesLayout (const AudioProcessor* juceFilter)
+    {
+       #ifdef JucePlugin_PreferredChannelConfigurations
+        AudioProcessor::BusesLayout layout = juceFilter->getBusesLayout();
+
+        for (int dir = 0; dir < 2; ++dir)
+        {
+            const bool isInput = (dir == 0);
+
+            const int actualBuses = juceFilter->getBusCount (isInput);
+            const int auNumBuses  = getBusCount (juceFilter, isInput);
+            Array<AudioChannelSet>& buses = (isInput ? layout.inputBuses : layout.outputBuses);
+
+            for (int i = auNumBuses; i < actualBuses; ++i)
+                buses.removeLast();
+        }
+
+        return layout;
+       #else
+        return juceFilter->getBusesLayout();
+       #endif
+    }
 };
 
 AudioUnitHelpers::AUChannelStreamOrder AudioUnitHelpers::StreamOrder::auChannelStreamOrder[] =