revamped the way event handlers join event contexts

(to eliminate some ugly widget construct/destruct situations)

minor: typo fix in south guard

minor: wassert clarification

data/campaigns/The_South_Guard/scenarios/7a.Into_The_Depths.cfg

@@ -475,7 +475,7 @@
 	
 	[message]
 		speaker=M'Brin
-		message= _ "Petty mortals, bow down and cower in fear before me, and I may make your passing swift. For I once one such as you, full of doubt and weakness,but now I have passed over and become more than you could possibly imagine."
+		message= _ "Petty mortals, bow down and cower in fear before me, and I may make your passing swift. For I was once one such as you, full of doubt and weakness, but now I have passed over and become more than you could possibly imagine."
 	[/message]
 	[message]
 		speaker=Deoran

doc/doxygen/doxygen.cpp

@@ -78,9 +78,10 @@ The program maintains a stack of event_context objects,
 the top of the stack being the active event_context.
 
 When an object of a type inheriting from handler is
-instantiated, it will be associated with the active event_context.
-As long as its event_context remains active, and only then, it will recieve
-all system events.
+instantiated, it will be associated with the active event_context
+(unless auto_join has been set false, in which case it can manually
+be instructed to join a later context). As long as its event_context
+remains active, and only then, it will recieve all system events.
 
 \note Multiple handler objects will recieve the same events, including key events.
 

src/dialogs.cpp

@@ -97,7 +97,6 @@ void advance_unit(const game_data& info,
 		res = rand()%lang_options.size();
 	} else if(lang_options.size() > 1) {
 
-		const events::event_context dialog_events_context;
 		unit_preview_pane unit_preview(gui,&map,sample_units);
 		std::vector<gui::preview_pane*> preview_panes;
 		preview_panes.push_back(&unit_preview);
@@ -517,8 +516,6 @@ std::string load_game_dialog(display& disp, const config& game_config, const gam
 		}
 	}
 
-	const events::event_context context;
-
 	if(generate_summaries) {
 		gui::progress_bar bar(disp.video());
 		const SDL_Rect bar_area = {disp.x()/2 - 100, disp.y()/2 - 20, 200, 40};

src/events.cpp

@@ -145,39 +145,49 @@ std::deque<context> event_contexts;
 
 } //end anon namespace
 
-event_context::event_context(bool create) : create_(create)
+event_context::event_context()
 {
-	if(create_) {
-		event_contexts.push_back(context());
-	}
+	event_contexts.push_back(context());
 }
 
 event_context::~event_context()
 {
-	if(create_) {
-		wassert(event_contexts.empty() == false);
-
-		event_contexts.pop_back();
-	}
+	wassert(event_contexts.empty() == false);
+	event_contexts.pop_back();
 }
 
-handler::handler() : unicode_(SDL_EnableUNICODE(1))
+handler::handler(bool auto_join) : unicode_(SDL_EnableUNICODE(1)), has_joined_(false)
 {
 	SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY,SDL_DEFAULT_REPEAT_INTERVAL);
-	event_contexts.back().add_handler(this);
+	if(auto_join) {
+		join();
+	}
 }
 
 handler::~handler()
 {
-	wassert(event_contexts.empty() == false);
+	leave();
+	SDL_EnableUNICODE(unicode_);
+}
 
+void handler::join()
+{
+	if(has_joined_) {
+		leave(); // should not be in multiple event contexts
+	}
+	event_contexts.back().add_handler(this);
+	has_joined_ = true;
+}
+
+void handler::leave()
+{
+	wassert(event_contexts.empty() == false);
 	for(std::deque<context>::reverse_iterator i = event_contexts.rbegin(); i != event_contexts.rend(); ++i) {
 		if(i->remove_handler(this)) {
 			break;
 		}
 	}
-
-	SDL_EnableUNICODE(unicode_);
+	//has_joined_ = false;
 }
 
 void focus_handler(const handler* ptr)

src/events.hpp

@@ -50,12 +50,17 @@ public:
 
 	virtual void process_help_string(int /*mousex*/, int /*mousey*/) {}
 
+	virtual void join(); /*joins the current event context*/
+
 protected:
-	handler();
+	handler(bool auto_join=true);
 	virtual ~handler();
 
 private:
+	void leave(); /*leave the event context*/
+
 	int unicode_;
+	bool has_joined_;
 };
 
 void focus_handler(const handler* ptr);
@@ -74,11 +79,8 @@ bool has_focus(const handler* ptr);
 //before their context is destroyed
 struct event_context
 {
-	event_context(bool create=true);
+	event_context();
 	~event_context();
-
-private:
-	bool create_;
 };
 
 //causes events to be dispatched to all handler objects.

src/menu_events.cpp

@@ -276,7 +276,6 @@ namespace events{
 		int selected = 0;
 
 		{
-			const events::event_context dialog_events_context;
 			dialogs::unit_preview_pane unit_preview(*gui_, &map_, units_list);
 			std::vector<gui::preview_pane*> preview_panes;
 			preview_panes.push_back(&unit_preview);
@@ -570,7 +569,6 @@ namespace events{
 		int recruit_res = 0;
 
 		{
-			const events::event_context dialog_events_context;
 			dialogs::unit_preview_pane unit_preview(*gui_,&map_,sample_units);
 			std::vector<gui::preview_pane*> preview_panes;
 			preview_panes.push_back(&unit_preview);
@@ -713,7 +711,6 @@ namespace events{
 			int res = 0;
 
 			{
-				const events::event_context dialog_events_context;
 				dialogs::unit_preview_pane unit_preview(*gui_,&map_,recall_list);
 				std::vector<gui::preview_pane*> preview_panes;
 				preview_panes.push_back(&unit_preview);
@@ -1155,7 +1152,6 @@ namespace events{
 		int choice = 0;
 
 		{
-			const events::event_context dialog_events_context;
 			dialogs::unit_preview_pane unit_preview(*gui_,&map_,unit_choices);
 			std::vector<gui::preview_pane*> preview_panes;
 			preview_panes.push_back(&unit_preview);

src/mouse_events.cpp

@@ -641,7 +641,6 @@ namespace{
 			const size_t index = size_t(selection);
 
 			if(index < bc_vector_.size()) {
-				const events::event_context dialog_event_context;
 				battle_prediction_pane battle_pane(disp_, bc_vector_[index], map_, teams_, units_, status_,
 												   gamedata_, attacker_loc_, defender_loc_);
 				std::vector<gui::preview_pane*> preview_panes;
@@ -1235,7 +1234,6 @@ bool mouse_handler::attack_enemy(unit_map::iterator attacker, unit_map::iterator
 	int res = 0;
 
 	{
-		const events::event_context dialog_events_context;
 		dialogs::unit_preview_pane attacker_preview(*gui_,&map_,attacker->second,dialogs::unit_preview_pane::SHOW_BASIC,true);
 		dialogs::unit_preview_pane defender_preview(*gui_,&map_,defender->second,dialogs::unit_preview_pane::SHOW_BASIC,false);
 		std::vector<gui::preview_pane*> preview_panes;

src/multiplayer_connect.cpp

@@ -313,7 +313,7 @@ void connect::side::hide_ai_algorithm_combo(bool invis)
 
 void connect::side::init_ai_algorithm_combo()
 {
-	wassert(!parent_->ai_algorithms_.empty());
+	wassert(parent_->ai_algorithms_.empty() == false);
 
 	int sel = 0;
 	std::vector<std::string> ais = parent_->ai_algorithms_;

src/multiplayer_wait.cpp

@@ -205,8 +205,6 @@ void wait::join_game(bool observe)
 		size_t faction_choice = 0;
 
 		if(allow_changes) {
-			events::event_context context;
-
 			const config* era = level_.child("era");
 			if(era == NULL)
 				throw network::error(_("Era not available"));

src/preferences_display.cpp

@@ -181,6 +181,8 @@ public:
 		TYPE type;
 	};
 
+	void join();
+
 private:
 
 	void process_event();
@@ -327,6 +329,45 @@ preferences_dialog::preferences_dialog(display& disp, const config& game_cfg)
 	set_advanced_menu();
 }
 
+void preferences_dialog::join()
+{
+	//join the current event_context
+	widget::join();
+
+	//instruct all member widgets to join the current event_context
+	music_slider_.join();
+	sound_slider_.join();
+	scroll_slider_.join();
+	gamma_slider_.join();
+	chat_lines_slider_.join();
+	fullscreen_button_.join();
+	turbo_button_.join();
+	show_ai_moves_button_.join();
+	show_grid_button_.join();
+	show_lobby_joins_button_.join();
+	show_floating_labels_button_.join();
+	turn_dialog_button_.join();
+	turn_bell_button_.join();
+	show_team_colours_button_.join();
+	show_colour_cursors_button_.join();
+	show_haloing_button_.join();
+	video_mode_button_.join();
+	theme_button_.join();
+	hotkeys_button_.join();
+	gamma_button_.join();
+	flip_time_button_.join();
+	advanced_button_.join();
+	sound_button_.join();
+	music_button_.join();
+	chat_timestamp_button_.join();
+	music_label_.join();
+	sound_label_.join();
+	scroll_label_.join();
+	gamma_label_.join();
+	chat_lines_label_.join();		
+	advanced_.join();
+}
+
 void preferences_dialog::update_location(SDL_Rect const &rect)
 {
 	bg_register(rect);
@@ -600,8 +641,8 @@ void show_preferences_dialog(display& disp, const config& game_cfg)
 
 	for(;;) {
 		try {
-			const events::event_context dialog_events_context;
-
+			//shield the current context from preference dialog members
+			const events::event_context shield_context;
 			preferences_dialog dialog(disp,game_cfg);
 			std::vector<gui::preview_pane*> panes;
 			panes.push_back(&dialog);

src/show_dialog.cpp

@@ -330,10 +330,8 @@ int show_dialog(display& disp, surface image,
 
 	LOG_DP << "showing dialog '" << caption << "' '" << msg << "'\n";
 
-	//create the event context, but only activate it if we don't have preview panes.
-	//the presence of preview panes indicates that the caller will create the context,
-	//so that their preview panes may fall inside it.
-	const events::event_context dialog_events_context(preview_panes == NULL);
+	//create the event context, remember to instruct any passed-in widgets to join it
+	const events::event_context dialog_events_context();
 	const dialog_manager manager;
 
 	const events::resize_lock prevent_resizing;
@@ -487,6 +485,7 @@ int show_dialog(display& disp, surface image,
 	size_t preview_pane_height = 0, left_preview_pane_width = 0, right_preview_pane_width = 0;
 	if(preview_panes != NULL) {
 		for(std::vector<preview_pane*>::const_iterator i = preview_panes->begin(); i != preview_panes->end(); ++i) {
+			(**i).join(); //join the event context now, since it was created outside this scope
 			const SDL_Rect& rect = (**i).location();
 
 			if((**i).show_above() == false) {

src/show_dialog.hpp

@@ -112,7 +112,7 @@ struct check_item {
 //by 'show_dialog' and shows information about the selection.
 class preview_pane : public widget {
 public:
-	preview_pane(CVideo &video) : widget(video) {}
+	preview_pane(CVideo &video) : widget(video, false) {}
 	virtual ~preview_pane() { tooltips::clear_tooltips(location()); }
 
 	virtual bool show_above() const { return false; }

src/widgets/widget.cpp

@@ -30,8 +30,8 @@ widget::widget(const widget &o)
 {
 }
 
-widget::widget(CVideo& video)
-	: video_(&video), rect_(EmptyRect), focus_(true), needs_restore_(false),
+widget::widget(CVideo& video, bool auto_join)
+	: handler(auto_join), video_(&video), rect_(EmptyRect), focus_(true), needs_restore_(false),
 	  state_(UNINIT), clip_(false), volatile_(false), help_string_(0), align_(RIGHT_ALIGN)
 {
 }

src/widgets/widget.hpp

@@ -70,7 +70,7 @@ public:
 
 protected:
 	widget(widget const &o);
-	widget(CVideo& video);
+	widget(CVideo& video, bool auto_join=true);
 	virtual ~widget();
 
 	// During each relocation, this function should be called to register