Lua class system

include/core/lua-int.hpp

@@ -41,4 +41,162 @@ void get_numeric_argument(lua_State* LS, unsigned argindex, T& value, const char
 	value = static_cast<T>(lua_tonumber(LS, argindex));
 }
 
+
+template<typename T> struct lua_obj_pin
+{
+	lua_obj_pin(lua_State* LS, T* _object)
+	{
+		lua_pushlightuserdata(LS, this);
+		lua_pushvalue(LS, -2);
+		lua_rawset(LS, LUA_REGISTRYINDEX);
+		state = LS;
+		obj = _object;
+	}
+	~lua_obj_pin()
+	{
+		lua_pushlightuserdata(state, this);
+		lua_pushnil(state);
+		lua_rawset(state, LUA_REGISTRYINDEX);
+	}
+	T* object() { return obj; }
+private:
+	T* obj;
+	lua_State* state;
+	lua_obj_pin(const lua_obj_pin&);
+	lua_obj_pin& operator=(const lua_obj_pin&);
+};
+
+template<class T> class lua_class;
+
+template<class T> lua_class<T>& objclass();
+
+template<class T> class lua_class
+{
+public:
+	lua_class(const std::string& _name)
+	{
+		name = _name;
+	}
+
+	template<typename... U> T* _create(lua_State* LS, U... args)
+	{
+		void* obj = lua_newuserdata(LS, sizeof(T));
+		load_metatable(LS);
+		lua_setmetatable(LS, -2);
+		T* _obj = reinterpret_cast<T*>(obj);
+		new(_obj) T(args...);
+		return _obj;
+	}
+
+	template<typename... U> static T* create(lua_State* LS, U... args)
+	{
+		return objclass<T>()._create(LS, args...);
+	}
+
+	void bind(lua_State* LS)
+	{
+		load_metatable(LS);
+		lua_pushvalue(LS, -3);
+		lua_pushvalue(LS, -3);
+		lua_rawset(LS, -3);
+	}
+
+	void bind(lua_State* LS, const char* keyname)
+	{
+		load_metatable(LS);
+		lua_pushstring(LS, keyname);
+		lua_pushvalue(LS, -3);
+		lua_rawset(LS, -3);
+	}
+
+	T* _get(lua_State* LS, int arg, const char* fname, bool optional = false)
+	{
+		if(lua_type(LS, arg) == LUA_TNONE || lua_type(LS, arg) == LUA_TNIL) {
+			if(optional)
+				return NULL;
+			else
+				goto badtype;
+		}
+		load_metatable(LS);
+		if(!lua_getmetatable(LS, arg))
+			goto badtype;
+		if(!lua_rawequal(LS, -1, -2))
+			goto badtype;
+		lua_pop(LS, 2);
+		return reinterpret_cast<T*>(lua_touserdata(LS, arg));
+badtype:
+		char buffer[2048];
+		sprintf(buffer, "argument #%i to %s must be %s", arg, fname, name.c_str());
+		lua_pushstring(LS, buffer);
+		lua_error(LS);
+	}
+
+	static T* get(lua_State* LS, int arg, const char* fname, bool optional = false)
+	{
+		return objclass<T>()._get(LS, arg, fname, optional);
+	}
+
+	bool _is(lua_State* LS, int arg)
+	{
+		if(lua_type(LS, arg) != LUA_TUSERDATA)
+			return false;
+		load_metatable(LS);
+		if(!lua_getmetatable(LS, arg)) {
+			lua_pop(LS, 1);
+			return false;
+		}
+		bool ret = lua_rawequal(LS, -1, -2);
+		lua_pop(LS, 2);
+		return ret;
+	}
+
+	static bool is(lua_State* LS, int arg)
+	{
+		return objclass<T>()._is(LS, arg);
+	}
+
+	lua_obj_pin<T>* _pin(lua_State* LS, int arg, const char* fname)
+	{
+		T* obj = get(LS, arg, fname);
+		lua_pushvalue(LS, arg);
+		return new lua_obj_pin<T>(LS, obj);
+	}
+
+	static lua_obj_pin<T>* pin(lua_State* LS, int arg, const char* fname)
+	{
+		return objclass<T>()._pin(LS, arg, fname);
+	}
+private:
+	static int dogc(lua_State* LS)
+	{
+		T* obj = reinterpret_cast<T*>(lua_touserdata(LS, 1));
+		obj->~T();
+	}
+
+	void load_metatable(lua_State* LS)
+	{
+again:
+		lua_pushlightuserdata(LS, this);
+		lua_rawget(LS, LUA_REGISTRYINDEX);
+		if(lua_type(LS, -1) == LUA_TNIL) {
+			lua_pop(LS, 1);
+			lua_pushlightuserdata(LS, this);
+			lua_newtable(LS);
+			lua_pushstring(LS, "__gc");
+			lua_pushcfunction(LS, &lua_class<T>::dogc);
+			lua_rawset(LS, -3);
+			lua_rawset(LS, LUA_REGISTRYINDEX);
+			goto again;
+		}
+	}
+	std::string name;
+	lua_class(const lua_class<T>&);
+	lua_class& operator=(const lua_class<T>&);
+};
+
+#define DECLARE_LUACLASS(x, X) template<> lua_class< x >& objclass() { static lua_class< x > clazz( X ); \
+	return clazz; }
+
+
+
 #endif