Track uuid->type mapping for ecs components and throw an exception when the same uuid is used for different components

libs/ecs/include/psemek/ecs/detail/component_registry.hpp

@@ -4,16 +4,50 @@
 #include <psemek/util/uuid.hpp>
 #include <psemek/util/hash_table.hpp>
 #include <psemek/util/function.hpp>
+#include <psemek/util/exception.hpp>
+#include <psemek/util/to_string.hpp>
 
 namespace psemek::ecs::detail
 {
 
+	struct duplicate_uuid_exception
+		: util::exception
+	{
+		duplicate_uuid_exception(util::uuid const & uuid, std::type_info const & type1, std::type_info const & type2, boost::stacktrace::stacktrace stacktrace = {})
+			: util::exception(util::to_string("Found duplicate UUID ", uuid, " for components ", util::type_name(type1), " and ", util::type_name(type2)), std::move(stacktrace))
+			, uuid_(uuid)
+			, type1_(type1)
+			, type2_(type2)
+		{}
+
+		util::uuid const & uuid() const { return uuid_; }
+		std::type_info const & type1() const { return type1_; }
+		std::type_info const & type2() const { return type2_; }
+
+	private:
+		util::uuid uuid_;
+		std::type_info const & type1_;
+		std::type_info const & type2_;
+	};
+
 	struct component_registry
 	{
 		template <typename Component>
 		void register_component()
 		{
-			column_factories_.insert({Component::uuid(), []{
+			auto const & uuid = Component::uuid();
+
+			if (auto it = types_.find(uuid); it != types_.end())
+			{
+				if (it->second != &typeid(Component))
+					throw duplicate_uuid_exception(uuid, *(it->second), typeid(Component));
+				else
+					return;
+			}
+
+			types_.insert({uuid, &typeid(Component)});
+
+			column_factories_.insert({uuid, []{
 				return std::make_unique<column_impl<Component>>();
 			}});
 		}
@@ -26,6 +60,7 @@ namespace psemek::ecs::detail
 		}
 
 	private:
+		util::hash_map<util::uuid, std::type_info const *> types_;
 		util::hash_map<util::uuid, util::function<std::unique_ptr<column>()>> column_factories_;
 	};