add late/lazy binding between generic MIDI bindings and controllable elements in the session. this allows you to load a binding map that refers to elements that have not yet been created in the session, and when they are created, the binding will work

git-svn-id: svn://localhost/ardour2/branches/3.0@12921 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/surfaces/generic_midi/generic_midi_control_protocol.cc

@@ -773,22 +773,27 @@ GenericMidiControlProtocol::reset_controllables ()
 
 			/* its entirely possible that the session doesn't have
 			 * the specified controllable (e.g. it has too few
-			 * tracks). if we find this to be the case, drop any
+			 * tracks). if we find this to be the case, we just leave
-			 * bindings that would be left without controllables.
+			 * the binding around, unbound, and it will do "late
+			 * binding" (or "lazy binding") if/when any data arrives.
 			 */
 
 			boost::shared_ptr<Controllable> c = session->controllable_by_descriptor (desc);
 			if (c) {
 				existingBinding->set_controllable (c.get());
-			} else {
+			} 
-				controllables.erase (iter);
-			}
 		}
 
 		iter = next;
 	}
 }
 
+boost::shared_ptr<Controllable>
+GenericMidiControlProtocol::lookup_controllable (const ControllableDescriptor& desc) const
+{
+	return session->controllable_by_descriptor (desc);
+}
+
 MIDIFunction*
 GenericMidiControlProtocol::create_function (const XMLNode& node)
 {

libs/surfaces/generic_midi/generic_midi_control_protocol.h

@@ -32,6 +32,7 @@ namespace MIDI {
 
 namespace PBD {
 	class Controllable;
+	class ControllableDescriptor;
 }	
 
 namespace ARDOUR {
@@ -57,6 +58,8 @@ class GenericMidiControlProtocol : public ARDOUR::ControlProtocol {
 	int set_feedback (bool yn);
 	bool get_feedback () const;
 
+        boost::shared_ptr<PBD::Controllable> lookup_controllable (const PBD::ControllableDescriptor&) const;
+
 	XMLNode& get_state ();
 	int set_state (const XMLNode&, int version);
 

libs/surfaces/generic_midi/midicontrollable.cc

@@ -184,11 +184,31 @@ MIDIControllable::midi_sense_note_off (Parser &p, EventTwoBytes *tb)
 	midi_sense_note (p, tb, false);
 }
 
+int
+MIDIControllable::lookup_controllable()
+{
+	if (!_descriptor) {
+		return -1;
+	}
+
+	boost::shared_ptr<Controllable> c = _surface->lookup_controllable (*_descriptor);
+
+	if (!c) {
+		return -1;
+	}
+
+	controllable = c.get();
+
+	return 0;
+}
+
 void
 MIDIControllable::midi_sense_note (Parser &, EventTwoBytes *msg, bool /*is_on*/)
 {
 	if (!controllable) { 
-		return;
+		if (lookup_controllable()) {
+			return;
+		}
 	}
 
 	if (!controllable->is_toggle()) {
@@ -206,7 +226,9 @@ void
 MIDIControllable::midi_sense_controller (Parser &, EventTwoBytes *msg)
 {
 	if (!controllable) { 
-		return;
+		if (lookup_controllable ()) {
+			return;
+		}
 	}
 
 	if (controllable->touching()) {
@@ -254,7 +276,9 @@ void
 MIDIControllable::midi_sense_program_change (Parser &, byte msg)
 {
 	if (!controllable) { 
-		return;
+		if (lookup_controllable ()) {
+			return;
+		}
 	}
 
 	if (!controllable->is_toggle()) {
@@ -270,7 +294,9 @@ void
 MIDIControllable::midi_sense_pitchbend (Parser &, pitchbend_t pb)
 {
 	if (!controllable) { 
-		return;
+		if (lookup_controllable ()) {
+			return;
+		}
 	}
 
 	if (!controllable->is_toggle()) {
@@ -299,7 +325,9 @@ MIDIControllable::midi_receiver (Parser &, byte *msg, size_t /*len*/)
 
 	bind_midi ((channel_t) (msg[0] & 0xf), eventType (msg[0] & 0xF0), msg[1]);
 
-	controllable->LearningFinished ();
+	if (controllable) {
+		controllable->LearningFinished ();
+	}
 }
 
 void

libs/surfaces/generic_midi/midicontrollable.h

@@ -116,6 +116,8 @@ class MIDIControllable : public PBD::Stateful
 	uint32_t        _rid;
 	std::string     _what;
 	bool            _bank_relative;
+
+        int lookup_controllable();
 	
 	void midi_receiver (MIDI::Parser &p, MIDI::byte *, size_t);
 	void midi_sense_note (MIDI::Parser &, MIDI::EventTwoBytes *, bool is_on);