add MIDITrack specific ::monitoring_state() method

git-svn-id: svn://localhost/ardour2/branches/3.0@11207 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/ardour/midi_track.h

@@ -108,6 +108,7 @@ public:
 	boost::shared_ptr<MidiBuffer> get_gui_feed_buffer () const;
 
 	void set_monitoring (MonitorChoice);
+	MonitorState monitoring_state () const;
 
 	void set_input_active (bool);
 	bool input_active () const;

libs/ardour/midi_track.cc

@@ -748,3 +748,29 @@ MidiTrack::set_monitoring (MonitorChoice mc)
 		md->reset_tracker ();
 	}
 }
+
+MonitorState
+MidiTrack::monitoring_state () const
+{
+	/* Explicit requests */
+	
+	if (_monitoring & MonitorInput) {
+		return MonitoringInput;
+	}
+		
+	if (_monitoring & MonitorDisk) {
+		return MonitoringDisk;
+	}
+
+	if (_session.transport_rolling()) {
+		return MonitoringDisk;
+	} 
+
+	/* the return value here doesn't mean that we're actually monitoring
+	 * input, let alone input *audio*. but it means that we are NOT 
+	 * monitoring silence. this allows us to still hear any audio generated
+	 * by using internal generation techniques
+	 */
+
+	return MonitoringInput;
+}