Game Events/Manager: added function to encapsulate iteration-by-id interface

This allows manager::iteration to be made private in order to restrict access to handler iterators
within the manager class and not outside it.

src/game_events/manager.cpp

@@ -204,6 +204,16 @@ void manager::write_events(config& cfg) const
 	wml_menu_items_.to_config(cfg);
 }
 
+void manager::execute_on_events(const std::string& event_id, manager::event_func_t func)
+{
+	iteration iter(event_id, *this);
+
+	while(handler_ptr hand = *iter) {
+		func(*this, hand);
+		++iter;
+	}
+}
+
 game_events::wml_event_pump& manager::pump()
 {
 	return *pump_;

src/game_events/manager.hpp

@@ -41,7 +41,7 @@ namespace game_events {
 	/// If a second manager object is created before destroying the previous
 	/// one, the game will crash with an assertion failure.
 	class manager {
-	public:
+	private:
 		/// This class is similar to an input iterator through event handlers,
 		/// except each instance knows its own end (determined when constructed).
 		/// Subsequent dereferences are not guaranteed to return the same element,
@@ -92,7 +92,6 @@ namespace game_events {
 			game_data * gamedata_;
 		};
 
-	private:
 		// Performs an assertion check to ensure these members are not null.
 		friend void event_handler::disable();
 
@@ -121,6 +120,9 @@ namespace game_events {
 		                const std::string& type = std::string());
 		void write_events(config& cfg) const;
 
+		using event_func_t = std::function<void(game_events::manager&, handler_ptr)>;
+		void execute_on_events(const std::string& event_id, event_func_t func);
+
 		game_events::wml_event_pump & pump();
 
 		game_events::wmi_manager& wml_menu_items()

src/game_events/menu_item.cpp

@@ -329,14 +329,13 @@ void wml_menu_item::update_command(const config& new_command)
 	// If there is an old command, remove it from the event handlers.
 	if(!command_.empty()) {
 		assert(resources::game_events);
-		manager::iteration iter(event_name_, *resources::game_events);
-		while(handler_ptr hand = *iter) {
-			if(hand->is_menu_item()) {
+
+		resources::game_events->execute_on_events(event_name_, [=](game_events::manager& man, handler_ptr ptr) {
+			if(ptr->is_menu_item()) {
 				LOG_NG << "Removing command for " << event_name_ << ".\n";
-				resources::game_events->remove_event_handler(command_["id"].str());
+				man.remove_event_handler(command_["id"].str());
 			}
-			++iter;
-		}
+		});
 	}
 
 	// Update our stored command.

src/game_events/pump.cpp

@@ -552,20 +552,16 @@ bool wml_event_pump::operator()()
 
 		if ( event_id.empty() ) {
 
-			// Initialize an iteration over event handlers matching this event.
-			manager::iteration handler_iter(event_name, *impl_->my_manager);
-
-			// While there is a potential handler for this event name.
-			while ( handler_ptr cur_handler = *handler_iter ) {
+			// Handle events of this name.
+			impl_->my_manager->execute_on_events(event_name, [=](game_events::manager&, handler_ptr ptr) {
 				DBG_EH << "processing event " << event_name << " with id="<<
-				cur_handler->get_config()["id"] << "\n";
+				ptr->get_config()["id"] << "\n";
+
 				// Let this handler process our event.
-				process_event(cur_handler, ev);
-				// NOTE: cur_handler may be null at this point!
-
-				++handler_iter;
-			}
+				process_event(ptr, ev);
 
+				// NOTE: ptr may be null at this point!
+			});
 		}
 		else {