Handle generic-midi bindings per session.

This allows to special-cases session-specific control-surface state.
e.g. midi-learn.

Only restore midi-learned, session-specific, bindings when loading a
session with generic-midi enabled.

Also dis/re-enable generic-midi resets midi-learned, but no other
session-independent settings.

This also handles the edge case:
 1) load global config, generic-midi = ON, w/ bindings.
    state is remembered as cpi->state
 2) load session-condig, generic-midi = OFF, cpi->state is retained
 3) user enables the surface, cpi->state from (1) is applied.
 -> invalid bindings applied -> fail

4 files changed, 9 insertions, 4 deletions

diff --git a/libs/ardour/control_protocol_manager.cc b/libs/ardour/control_protocol_manager.cc
index c1c595ebb2..048ff3f7d5 100644
--- a/libs/ardour/control_protocol_manager.cc
+++ b/libs/ardour/control_protocol_manager.cc
@@ -452,7 +452,7 @@ ControlProtocolManager::cpi_by_name (string name)
 }
 
 int
-ControlProtocolManager::set_state (const XMLNode& node, int /*version*/)
+ControlProtocolManager::set_state (const XMLNode& node, int session_specific_state /* here: not version */)
 {
 	XMLNodeList clist;
 	XMLNodeConstIterator citer;
@@ -483,6 +483,7 @@ ControlProtocolManager::set_state (const XMLNode& node, int /*version*/)
 				if (active) {
 					delete cpi->state;
 					cpi->state = new XMLNode (**citer);
+					cpi->state->set_property (X_("session-state"), session_specific_state ? true : false);
 					if (_session) {
 						instantiate (*cpi);
 					} else {
@@ -492,6 +493,7 @@ ControlProtocolManager::set_state (const XMLNode& node, int /*version*/)
 					if (!cpi->state) {
 						cpi->state = new XMLNode (**citer);
 						cpi->state->set_property (X_("active"), false);
+						cpi->state->set_property (X_("session-state"), session_specific_state ? true : false);
 					}
 					cpi->requested = false;
 					if (_session) {
diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index fc17b3a5e9..eab0b93a41 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -599,7 +599,7 @@ ARDOUR::init_post_engine ()
 	XMLNode* node;
 
 	if ((node = Config->control_protocol_state()) != 0) {
-		ControlProtocolManager::instance().set_state (*node, Stateful::loading_state_version);
+		ControlProtocolManager::instance().set_state (*node, 0 /* here: global-config state */);
 	}
 
 	if ((node = Config->transport_master_state()) != 0) {
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 1335c554cb..0c974fcc84 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -1729,7 +1729,7 @@ Session::set_state (const XMLNode& node, int version)
 	}
 
 	if ((child = find_named_node (node, ControlProtocolManager::state_node_name)) != 0) {
-		ControlProtocolManager::instance().set_state (*child, version);
+		ControlProtocolManager::instance().set_state (*child, 1 /* here: session-specific state */);
 	}
 
 	if ((child = find_named_node (node, "Script"))) {
diff --git a/libs/surfaces/generic_midi/generic_midi_control_protocol.cc b/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
index 4d931b8fe0..214c9fede7 100644
--- a/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
+++ b/libs/surfaces/generic_midi/generic_midi_control_protocol.cc
@@ -669,7 +669,10 @@ GenericMidiControlProtocol::set_state (const XMLNode& node, int version)
 	 * <Controls><MidiControllable>...</MidiControllable><Controls> section
 	 */
 
-	{
+	bool load_dynamic_bindings = false;
+	node.get_property ("session-state", load_dynamic_bindings);
+
+	if (load_dynamic_bindings) {
 		Glib::Threads::Mutex::Lock lm2 (controllables_lock);
 		nlist = node.children(); // "Controls"