Revert "put [resource] before other content; fixes #3345"

This reverts commit 7067402209.

The commit used the `pos` iterator after invalidating
it (passing an iterator to `config::add_child_at()`
invalidates it), resulting in undefined behavior.

src/config.cpp

@@ -542,42 +542,6 @@ config& config::add_child_at(config_key_type key, const config& val, unsigned in
 	return *v[index];
 }
 
-config& config::add_child_at(config_key_type key, const config &val, const const_all_children_iterator& pos)
-{
-	if(pos == ordered_end()) {
-		//optimisation
-		config::add_child(key, val);
-	}
-
-	auto end = ordered_children.end();
-	assert(pos.i_ <= end);
-
-	auto pos_it = ordered_children.begin() + (pos.i_ - ordered_children.begin()); //'const cast'.
-	auto next = std::find_if(pos_it, end,[&](const child_pos& p){ return p.pos->first == key; });
-	
-	if(next == end) {
-		config& res = config::add_child(key, val);
-		std::rotate( pos_it, ordered_children.end(), ordered_children.end());
-		return res;
-	}
-
-	auto pl = next->pos;
-	child_list& l = pl->second;
-	unsigned int index = next->index;
-	config& res = **(l.emplace(l.begin() + index, new config(val)));
-	
-	for(auto ord = next; ord != end; ++ord) {
-		//this changes next->index and all later refernces to that tag.
-		if(ord->pos == pl) {
-			++ord->index;
-		}
-	}
-
-	//finally insert our new child in ordered_children.
-	ordered_children.insert(pos.i_, { pl, index });
-	return res;
-}
-
 namespace
 {
 struct remove_ordered

src/config.hpp

@@ -624,7 +624,7 @@ public:
 		typedef std::vector<child_pos>::const_iterator Itor;
 		typedef const_all_children_iterator this_type;
 		explicit const_all_children_iterator(const Itor &i): i_(i) {}
-		const_all_children_iterator(const all_children_iterator& i): i_(i.i_) {}
+		const_all_children_iterator(all_children_iterator& i): i_(i.i_) {}
 
 		const_all_children_iterator &operator++() { ++i_; return *this; }
 		const_all_children_iterator operator++(int) { return const_all_children_iterator(i_++); }
@@ -659,8 +659,6 @@ public:
 		friend class config;
 	};
 
-	config& add_child_at(config_key_type key, const config &val, const const_all_children_iterator& pos);
-
 	typedef boost::iterator_range<all_children_iterator> all_children_itors;
 	typedef boost::iterator_range<const_all_children_iterator> const_all_children_itors;
 

src/saved_game.cpp

@@ -298,7 +298,7 @@ struct modevents_entry
 
 } // end anon namespace
 
-void saved_game::load_mod(const std::string& type, const std::string& id, config::all_children_iterator pos)
+void saved_game::load_mod(const std::string& type, const std::string& id)
 {
 	if(const config& cfg = game_config_manager::get()->game_config().find_child(type, "id", id)) {
 		// Note the addon_id if this mod is required to play the game in mp.
@@ -323,18 +323,18 @@ void saved_game::load_mod(const std::string& type, const std::string& id, config
 			if(modevent["enable_if"].empty()
 				|| variable_to_bool(carryover_.child_or_empty("variables"), modevent["enable_if"])
 			) {
-				this->starting_point_.add_child_at("event", modevent, pos++);
+				this->starting_point_.add_child("event", modevent);
 			}
 		}
 
 		// Copy lua
 		for(const config& modlua : cfg.child_range("lua")) {
-			this->starting_point_.add_child_at("lua", modlua, pos++);
+			this->starting_point_.add_child("lua", modlua);
 		}
 
 		// Copy load_resource
 		for(const config& load_resource : cfg.child_range("load_resource")) {
-			this->starting_point_.add_child_at("load_resource", load_resource, pos++);
+			this->starting_point_.add_child("load_resource", load_resource);
 		}
 	} else {
 		// TODO: A user message instead?
@@ -367,24 +367,25 @@ void saved_game::expand_mp_events()
 			mods.emplace_back("campaign", classification_.campaign);
 		}
 
-		for(modevents_entry& mod : mods) {
-			load_mod(mod.type, mod.id, this->starting_point_.ordered_end());
-		}
-		mods.clear();
-
-		while(starting_point_.has_child("load_resource")) {
-			//todo: this looks like too much exposure of configs internals.
-			auto pos = std::find_if(starting_point_.ordered_begin(), starting_point_.ordered_end(), [&](const config::any_child& can){ return can.key == "load_resource"; });
-			assert(pos != starting_point_.ordered_end());
-			//assert(pos->index == 0);
-			std::string id = pos->cfg["id"];
-			starting_point_.remove_child("load_resource", 0);
-			//pos is still valid because starting_point_.ordered_begin() is a vector iterator.
-			if(loaded_resources.find(id) == loaded_resources.end()) {
-				loaded_resources.insert(id);
-				load_mod("resource", id, pos);
+		// In the first iteration mod contains no [resource]s in all other iterations, mods contains only [resource]s.
+		do {
+			for(modevents_entry& mod : mods) {
+				load_mod(mod.type, mod.id);
 			}
-		}
+
+			mods.clear();
+
+			for(const config& cfg : starting_point_.child_range("load_resource")) {
+				if(loaded_resources.find(cfg["id"].str()) == loaded_resources.end()) {
+					mods.emplace_back("resource", cfg["id"].str());
+
+					loaded_resources.insert(cfg["id"].str());
+				}
+			}
+
+			starting_point_.clear_children("load_resource");
+		} while(!mods.empty());
+
 		this->starting_point_["has_mod_events"] = true;
 	}
 }

src/saved_game.hpp

@@ -72,7 +72,7 @@ public:
 	/// should be called after expand_scenario() but before expand_carryover()
 	void expand_mp_events();
 	/// helper for expand_mp_events();
-	void load_mod(const std::string& type, const std::string& id, config::all_children_iterator pos);
+	void load_mod(const std::string& type, const std::string& id);
 	/// adds values of [option]s into [carryover_sides_start][variables] so that they are applied in the next level.
 	/// Note that since [variabels] are persistent we only use this once at the beginning
 	/// of a campaign but calling it multiple times is no harm eigher