CPM: Implement automatic ctrl-surface activision

libs/ardour/ardour/control_protocol_manager.h

@@ -74,6 +74,7 @@ class LIBARDOUR_API ControlProtocolManager : public PBD::Stateful, public ARDOUR
 	void foreach_known_protocol (boost::function<void(const ControlProtocolInfo*)>);
 	void midi_connectivity_established ();
 	void drop_protocols ();
+	void probe_midi_control_protocols ();
 
 	int activate (ControlProtocolInfo&);
         int deactivate (ControlProtocolInfo&);

libs/ardour/ardour/rc_configuration_vars.h

@@ -89,6 +89,7 @@ CONFIG_VARIABLE (float, ltc_output_volume, "ltc-output-volume", 0.125893)
 
 CONFIG_VARIABLE (uint32_t, feedback_interval_ms,  "feedback-interval-ms", 100)
 CONFIG_VARIABLE (bool, use_tranzport,  "use-tranzport", false)
+CONFIG_VARIABLE (bool, auto_enable_surfaces, "auto-enable-surfaces", true)
 
 /* disk operations */
 

libs/ardour/ardour/session.h

@@ -2323,6 +2323,9 @@ private:
 	void setup_click_state (const XMLNode*);
 	void setup_bundles ();
 
+	void port_registry_changed ();
+	void probe_ctrl_surfaces ();
+
 	void save_as_bring_callback (uint32_t, uint32_t, std::string);
 
 	static const uint32_t session_end_shift;

libs/ardour/control_protocol_manager.cc

@@ -382,6 +382,7 @@ ControlProtocolManager::control_protocol_discover (string path)
 			cpi->path = path;
 			cpi->protocol = 0;
 			cpi->requested = false;
+			cpi->automatic = false;
 			cpi->state = 0;
 
 			control_protocol_info.push_back (cpi);
@@ -512,7 +513,7 @@ ControlProtocolManager::get_state () const
 
 		if ((*i)->protocol) {
 			XMLNode& child_state ((*i)->protocol->get_state());
-			child_state.set_property (X_("active"), true);
+			child_state.set_property (X_("active"), !(*i)->automatic);
 			delete ((*i)->state);
 			(*i)->state = new XMLNode (child_state);
 			root->add_child_nocopy (child_state);
@@ -553,6 +554,38 @@ ControlProtocolManager::midi_connectivity_established ()
 	}
 }
 
+void
+ControlProtocolManager::probe_midi_control_protocols ()
+{
+	if (!Config->get_auto_enable_surfaces ()) {
+		return;
+	}
+	for (auto const& cpi : control_protocol_info) {
+		/* Note: manual teardown deletes the descriptor */
+		if (!cpi->descriptor) {
+			cpi->automatic = false;
+			continue;
+		}
+		if (!cpi->descriptor->probe_port) {
+			continue;
+		}
+		bool active = 0 != cpi->protocol;
+		bool found = cpi->descriptor->probe_port ();
+
+		if (!active && found) {
+			cpi->automatic = true;
+			activate (*cpi);
+		} else if (active && cpi->automatic && !found) {
+			cpi->automatic = false;
+			deactivate (*cpi);
+			/* allow to auto-enable again */
+			if (!cpi->descriptor) {
+				cpi->descriptor = get_descriptor (cpi->path);
+			}
+		}
+	}
+}
+
 void
 ControlProtocolManager::stripable_selection_changed (StripableNotificationListPtr sp)
 {

libs/ardour/session.cc

@@ -597,7 +597,7 @@ Session::immediately_post_engine ()
 
 	/* TODO, connect in different thread. (PortRegisteredOrUnregistered may be in RT context)
 	 * can we do that? */
-	 _engine.PortRegisteredOrUnregistered.connect_same_thread (*this, boost::bind (&Session::setup_bundles, this));
+	 _engine.PortRegisteredOrUnregistered.connect_same_thread (*this, boost::bind (&Session::port_registry_changed, this));
 	 _engine.PortPrettyNameChanged.connect_same_thread (*this, boost::bind (&Session::setup_bundles, this));
 
 	// set samplerate for plugins added early
@@ -871,6 +871,21 @@ Session::destroy ()
 	BOOST_SHOW_POINTERS ();
 }
 
+void
+Session::port_registry_changed()
+{
+	setup_bundles ();
+	_butler->delegate (boost::bind (&Session::probe_ctrl_surfaces, this));
+}
+
+void
+Session::probe_ctrl_surfaces()
+{
+	if (!_engine.running() || deletion_in_progress ()) {
+		return;
+	}
+	ControlProtocolManager::instance ().probe_midi_control_protocols ();
+}
 
 void
 Session::block_processing()