util: try to check for leaked userdata?!?

related to #27

Author: RaphaelIT7

source/lua.cpp

@@ -92,14 +92,24 @@ void Lua::Shutdown()
 
 void Lua::FinalShutdown()
 {
+	// g_Lua is bad at this point / the lua_State is already gone so we CAN'T allow any calls
 	g_Lua = NULL;
-	
+
+	for (auto& ref : g_pLuaUserData)
+	{
+		if (Util::holylib_debug_mainutil.GetBool())
+			Msg("holylib: Discarding of old userdata %p\n", ref);
+
+		// if g_Lua was not NULL it would attempt to free the references.
+		delete ref;
+	}
+	g_pLuaUserData.clear();
+
 	for (auto& ref : Util::g_pReference)
 	{
 		if (Util::holylib_debug_mainutil.GetBool())
 			Msg("holylib: Discarding of old reference %i\n", ref);
 	}
-
 	Util::g_pReference.clear();
 }
 

source/util.cpp

@@ -16,6 +16,7 @@ GarrysMod::Lua::ILuaInterface* g_Lua;
 IVEngineServer* engine;
 CGlobalEntityList* Util::entitylist = NULL;
 CUserMessages* Util::pUserMessages;
+std::unordered_set<LuaUserData*> g_pLuaUserData;
 
 std::unordered_set<int> Util::g_pReference;
 ConVar Util::holylib_debug_mainutil("holylib_debug_mainutil", "1");

source/util.h

@@ -220,14 +220,22 @@ namespace Util
 	ToDo: Implement a proper class like gmod has with CLuaCLass/CLuaLibrary & use thoes instead for everything.
 */
 
+struct LuaUserData;
+extern std::unordered_set<LuaUserData*> g_pLuaUserData;
 struct LuaUserData {
+	LuaUserData() {
+		g_pLuaUserData.insert(this);
+	}
+
 	~LuaUserData() {
 		if (!ThreadInMainThread())
 		{
 			Warning("holylib: Tried to delete usetdata from another thread!\n");
 			return;
 		}
 
+		g_pLuaUserData.erase(this);
+
 		if (iReference != -1)
 		{
 			if (g_Lua)