iOS: trying 2 fixes in gui2::execute_timer() and gui2::timer_callback(): timer thread safety or tooltips.

timer callback can invoke whole stack of the windows. Don't lock the timers forever.

src/gui/core/event/distributor.cpp

@@ -344,6 +344,14 @@ void mouse_motion::mouse_leave()
 void mouse_motion::start_hover_timer(widget* widget, const point& coordinate)
 {
 	assert(widget);
+
+#ifdef __IPHONEOS__
+	// Guessing a crash location in a nasty stack in gui2::execute_timer.
+	// Either this or a long-touch menu.
+	// Remove this when the crash in gui2::execute_timer() and gui2::timer_callback() is gone and try again.
+	return;
+#endif
+
 	stop_hover_timer();
 
 	if(hover_shown_ || !widget->wants_mouse_hover()) {

src/gui/core/timer.cpp

@@ -20,6 +20,7 @@
 #include <SDL_timer.h>
 
 #include <map>
+#include <mutex>
 
 namespace gui2
 {
@@ -53,6 +54,8 @@ static std::map<std::size_t, timer>& get_timers()
 */
 static std::size_t executing_id = 0;
 
+std::mutex timers_mutex;
+
 /** Did somebody try to remove the timer during its execution? */
 static bool executing_id_removed = false;
 
@@ -93,11 +96,17 @@ extern "C" {
 static uint32_t timer_callback(uint32_t, void* id)
 {
 	DBG_GUI_E << "Pushing timer event in queue.\n";
+	// iTunes still reports a couple of crashes here. Cannot see a problem yet.
 
-	std::map<std::size_t, timer>::iterator itor
-			= get_timers().find(reinterpret_cast<std::size_t>(id));
-	if(itor == get_timers().end()) {
-		return 0;
+	Uint32 result;
+	{
+		std::lock_guard<std::mutex> lock(timers_mutex);
+
+		auto itor = get_timers().find(reinterpret_cast<std::size_t>(id));
+		if(itor == get_timers().end()) {
+			return 0;
+		}
+		result = itor->second.interval;
 	}
 
 	SDL_Event event;
@@ -109,7 +118,7 @@ static uint32_t timer_callback(uint32_t, void* id)
 
 	SDL_PushEvent(&event);
 
-	return itor->second.interval;
+	return result;
 }
 
 } // extern "C"
@@ -122,13 +131,18 @@ std::size_t add_timer(const uint32_t interval,
 
 	DBG_GUI_E << "Adding timer.\n";
 
-	do {
-		++next_timer_id;
-	} while(next_timer_id == 0 || get_timers().find(next_timer_id) != get_timers().end());
-
 	timer timer;
-	timer.sdl_id = SDL_AddTimer(
-			interval, timer_callback, reinterpret_cast<void*>(next_timer_id));
+	{
+		std::lock_guard<std::mutex> lock(timers_mutex);
+
+		do {
+			++next_timer_id;
+		} while(next_timer_id == 0 || get_timers().count(next_timer_id) > 0);
+
+		timer.sdl_id = SDL_AddTimer(
+				interval, timer_callback, reinterpret_cast<void*>(next_timer_id));
+	}
+
 	if(timer.sdl_id == 0) {
 		WRN_GUI_E << "Failed to create an sdl timer." << std::endl;
 		return 0;
@@ -140,7 +154,11 @@ std::size_t add_timer(const uint32_t interval,
 
 	timer.callback = callback;
 
-	get_timers().emplace(next_timer_id, timer);
+	{
+		std::lock_guard<std::mutex> lock(timers_mutex);
+
+		get_timers().emplace(next_timer_id, timer);
+	}
 
 	DBG_GUI_E << "Added timer " << next_timer_id << ".\n";
 	return next_timer_id;
@@ -150,7 +168,9 @@ bool remove_timer(const std::size_t id)
 {
 	DBG_GUI_E << "Removing timer " << id << ".\n";
 
-	std::map<std::size_t, timer>::iterator itor = get_timers().find(id);
+	std::lock_guard<std::mutex> lock(timers_mutex);
+
+	auto itor = get_timers().find(id);
 	if(itor == get_timers().end()) {
 		LOG_GUI_E << "Can't remove timer since it no longer exists.\n";
 		return false;
@@ -181,20 +201,25 @@ bool execute_timer(const std::size_t id)
 {
 	DBG_GUI_E << "Executing timer " << id << ".\n";
 
-	std::map<std::size_t, timer>::iterator itor = get_timers().find(id);
-	if(itor == get_timers().end()) {
-		LOG_GUI_E << "Can't execute timer since it no longer exists.\n";
-		return false;
-	}
-
+	std::function<void(size_t)> callback = nullptr;
 	{
-		executor executor(id);
-		itor->second.callback(id);
+		std::lock_guard<std::mutex> lock(timers_mutex);
+
+		std::map<size_t, timer>::iterator itor = get_timers().find(id);
+		if(itor == get_timers().end()) {
+			LOG_GUI_E << "Can't execute timer since it no longer exists.\n";
+			return false;
+		}
+
+		callback = itor->second.callback;
+
+		if(itor->second.interval == 0) {
+			get_timers().erase(itor);
+		}
 	}
 
-	if(!executing_id_removed && itor->second.interval == 0) {
-		get_timers().erase(itor);
-	}
+	callback(id);
+
 	return true;
 }