[Summary] Added cleanup for GUI properties when route is removed.

[Details] This issue caused serious overhead when adding new routes after previous were removed. Also it resulted in garbage info saved in session file.
[Reviewed by] PDavis, YPozdnyakov

gtk2_ardour/automation_time_axis.cc

@@ -231,6 +231,7 @@ AutomationTimeAxisView::AutomationTimeAxisView (
 
 AutomationTimeAxisView::~AutomationTimeAxisView ()
 {
+    cleanup_gui_properties ();
 	delete _view;
 }
 

gtk2_ardour/axis_view.h

@@ -70,6 +70,14 @@ class AxisView : public virtual Selectable, public PBD::ScopedConnectionList, pu
 		property_hashtable.emplace(property_name, s.str());
 		gui_object_state().set_property<T> (state_id(), property_name, value);
 	}
+    
+    void cleanup_gui_properties ()
+    {
+        // remove related property node from the GUI state
+        gui_object_state().remove_node(state_id() );
+        property_hashtable.clear ();
+    }
+
 
 	bool marked_for_display () const;
 	virtual bool set_marked_for_display (bool);

gtk2_ardour/gui_object.cc

@@ -71,6 +71,46 @@ GUIObjectState::get_or_add_node (const string& id)
 	return get_or_add_node (&_state, id);
 }
 
+/** Remove property from the node with provided id.
+ *  If there is no properties except the node id - remove the node.
+ *  @param id property of Object node to look for.
+ *  @param prop_name name of the Object property to remove.
+ *  @return value of true if property is found, or false if not.
+ */
+
+bool
+GUIObjectState::remove_property (const std::string& id, const std::string& prop_name)
+{
+    XMLNode* child = get_node (&_state, id);
+    
+    if (!child) {
+        return false;
+    }
+    
+    XMLProperty* p = child->property (prop_name );
+    if (!p) {
+        return false;
+    }
+    
+    child->remove_property (prop_name );
+    
+    if (child->children().empty() && child->properties().size() == 1 && child->property (X_("id")) ) {
+        remove_node (id);
+    }
+    
+    return true;
+}
+
+/** Remove node with provided id.
+ *  @param id property of Object node to look for.
+*/
+
+void
+GUIObjectState::remove_node (const std::string& id)
+{
+    _state.remove_nodes_and_delete(X_("id"), id );
+}
+
 /** Get a string from our state.
  *  @param id property of Object node to look for.
  *  @param prop_name name of the Object property to return.

gtk2_ardour/gui_object.h

@@ -47,12 +47,16 @@ public:
 		s << val;
 		child->add_property (prop_name.c_str(), s.str());
 	}
-
+    
+    bool remove_property (const std::string& id, const std::string& prop_name);
+    
 	std::list<std::string> all_ids () const;
 
 	static XMLNode* get_node (const XMLNode *, const std::string &);
 	XMLNode* get_or_add_node (const std::string &);
 	static XMLNode* get_or_add_node (XMLNode *, const std::string &);
+    
+    void remove_node (const std::string& id);
 	
   private:
 	XMLNode _state;

gtk2_ardour/route_time_axis.cc

@@ -228,6 +228,9 @@ RouteTimeAxisView::set_route (boost::shared_ptr<Route> rt)
 
 RouteTimeAxisView::~RouteTimeAxisView ()
 {
+    // must be handled before CatchDeletion (this)
+    cleanup_gui_properties ();
+    
 	CatchDeletion (this);
 
 	for (list<ProcessorAutomationInfo*>::iterator i = processor_automation.begin(); i != processor_automation.end(); ++i) {

gtk2_ardour/route_ui.cc

@@ -102,9 +102,13 @@ RouteUI::RouteUI (ARDOUR::Session* sess, const std::string& layout_script_file)
 
 RouteUI::~RouteUI()
 {
+    // remove RouteUI property node from the GUI state
+    // must be handled before reseting _route
+    gui_object_state().remove_node(route_state_id() );
+    
 	_route.reset (); /* drop reference to route, so that it can be cleaned up */
 	route_connections.drop_connections ();
-
+    
 	delete solo_menu;
 	delete mute_menu;
 	delete sends_menu;