1 files changed, 80 insertions, 2 deletions
diff --git a/libs/appleutility/CAAudioUnit.cpp b/libs/appleutility/CAAudioUnit.cpp
index aaf57f233d..0e2cdbfe49 100644
--- a/libs/appleutility/CAAudioUnit.cpp
+++ b/libs/appleutility/CAAudioUnit.cpp
@@ -223,24 +223,102 @@ CAAudioUnit::CAAudioUnit (const AudioUnit& inUnit)
 }
 
 CAAudioUnit::CAAudioUnit (const CAComponent& inComp)
-	: mComp (inComp), mDataPtr (0)
+	: mComp (inComp), mDataPtr (0), mPropertyCallback (0)
 {
 	mDataPtr = new AUState (mComp.Comp());
 }
 
 CAAudioUnit::CAAudioUnit (const AUNode &inNode, const AudioUnit& inUnit)
-	: mComp (inUnit), mDataPtr(new AUState (inNode, inUnit)) 
+	: mComp (inUnit), mDataPtr(new AUState (inNode, inUnit)), mPropertyCallback (0)
 {
 }
 
 CAAudioUnit::~CAAudioUnit ()
 {
+	dropPropertyListens ();
+
 	if (mDataPtr) {
 		mDataPtr->release();
 		mDataPtr = NULL;
 	}
 }
 
+void
+CAAudioUnit::addPropertyListen (AudioUnitPropertyID id)
+{
+	if (mPropertyCallback == 0) {
+		return;
+	}
+
+	if (mWatching.find (id) != mWatching.end()) {
+		return;
+	}
+
+	if (AudioUnitAddPropertyListener (AU(), id, PropertyCallback, this) == noErr) {
+		mWatching.insert (id);
+	}
+}
+
+void
+CAAudioUnit::removePropertyListen (AudioUnitPropertyID id)
+{
+	if (!mPropertyCallback) {
+		return;
+	}
+	std::set<AudioUnitPropertyID>::iterator i = mWatching.find (id);
+	if (i != mWatching.end()) {
+		mWatching.erase (i);
+	}
+	/* this is for 10.6 and above ...
+	   AudioUnitRemovePropertyListenerWithUserData (AU(), id, PropertyCallback, this);
+	*/
+	AudioUnitRemovePropertyListener (AU(), id, PropertyCallback);
+}
+
+void
+CAAudioUnit::dropPropertyListens ()
+{
+	for (std::set<AudioUnitPropertyID>::iterator i = mWatching.begin(); i != mWatching.end(); ++i) {
+		/* this is for 10.6 and above ...
+		AudioUnitRemovePropertyListenerWithUserData (AU(), *i, PropertyCallback, this);
+		*/
+		AudioUnitRemovePropertyListener (AU(), *i, PropertyCallback);
+	}
+	mWatching.clear ();
+}
+
+void
+CAAudioUnit::SetPropertyCallback (void (*prop_callback)(void*, int32_t, float, void*), void* arg)
+{
+	dropPropertyListens ();
+	mPropertyCallback = prop_callback;
+	mPropertyCallbackArg = arg;
+}
+
+void
+CAAudioUnit::PropertyCallback (void                *inRefCon,
+			       AudioUnit            inUnit,
+			       AudioUnitPropertyID  inID,
+			       AudioUnitScope       inScope,
+			       AudioUnitElement     inElement)
+{
+	static_cast<CAAudioUnit*>(inRefCon)->
+		DoPropertyCallback (inUnit, inID, inScope, inElement);
+}
+
+void
+CAAudioUnit::DoPropertyCallback (AudioUnit            inUnit,
+				 AudioUnitPropertyID  inID,
+				 AudioUnitScope       inScope,
+				 AudioUnitElement     inElement)
+{
+	if (mPropertyCallback) {
+		float value;
+		AudioUnitGetParameter (inUnit, inID, inScope, inElement, &value);
+		mPropertyCallback (this, inID, value, mPropertyCallbackArg);
+	}
+}
+
 CAAudioUnit&	CAAudioUnit::operator= (const CAAudioUnit &a)
 {
 	if (mDataPtr != a.mDataPtr) {