Fix Lua reference leaks (fixes #638)

src/graphics/Renderer.cpp

@@ -18,6 +18,7 @@
 #ifdef LUACONSOLE
 #include "lua/LuaScriptInterface.h"
 #include "lua/LuaScriptHelper.h"
+#include "lua/LuaSmartRef.h"
 #endif
 #include "hmap.h"
 #ifdef OGLR

src/gui/interface/Window.cpp

@@ -80,6 +80,7 @@ void Window::RemoveComponent(Component* c)
 			Components.erase(Components.begin() + i);
 
 			// we're done
+			c->SetParentWindow(NULL);
 			return;
 		}
 	}

src/lua/LegacyLuaAPI.cpp

@@ -8,6 +8,7 @@
 #include "Format.h"
 #include "LuaScriptInterface.h"
 #include "LuaScriptHelper.h"
+#include "LuaSmartRef.h"
 #include "Platform.h"
 #include "PowderToy.h"
 
@@ -136,7 +137,7 @@ int luacon_partsread(lua_State* l)
 	if (i < 0 || i >= NPART)
 		return luaL_error(l, "array index out of bounds");
 
-	lua_rawgeti(l, LUA_REGISTRYINDEX, tptPart);
+	lua_rawgeti(l, LUA_REGISTRYINDEX, *tptPart);
 	cIndex = i;
 	return 1;
 }
@@ -317,12 +318,9 @@ int luatpt_element_func(lua_State *l)
 	{
 		int element = luaL_optint(l, 2, 0);
 		int replace = luaL_optint(l, 3, 0);
-		int function;
-		lua_pushvalue(l, 1);
-		function = luaL_ref(l, LUA_REGISTRYINDEX);
 		if(element > 0 && element < PT_NUM)
 		{
-			lua_el_func[element] = function;
+			lua_el_func[element].Assign(1);
 			if (replace == 2)
 				lua_el_mode[element] = 3; //update before
 			else if (replace)
@@ -341,7 +339,7 @@ int luatpt_element_func(lua_State *l)
 		int element = luaL_optint(l, 2, 0);
 		if(element > 0 && element < PT_NUM)
 		{
-			lua_el_func[element] = 0;
+			lua_el_func[element].Clear();
 			lua_el_mode[element] = 0;
 		}
 		else
@@ -390,12 +388,9 @@ int luatpt_graphics_func(lua_State *l)
 	if(lua_isfunction(l, 1))
 	{
 		int element = luaL_optint(l, 2, 0);
-		int function;
-		lua_pushvalue(l, 1);
-		function = luaL_ref(l, LUA_REGISTRYINDEX);
 		if (element > 0 && element < PT_NUM)
 		{
-			lua_gr_func[element] = function;
+			lua_gr_func[element].Assign(1);
 			luacon_ren->graphicscache[element].isready = 0;
 			return 0;
 		}
@@ -409,7 +404,7 @@ int luatpt_graphics_func(lua_State *l)
 		int element = luaL_optint(l, 2, 0);
 		if (element > 0 && element < PT_NUM)
 		{
-			lua_gr_func[element] = 0;
+			lua_gr_func[element].Clear();
 			luacon_ren->graphicscache[element].isready = 0;
 			return 0;
 		}

src/lua/LuaButton.cpp

@@ -20,7 +20,7 @@ Luna<LuaButton>::RegType LuaButton::methods[] = {
 
 LuaButton::LuaButton(lua_State * l) :
 	LuaComponent(l),
-	actionFunction(0)
+	actionFunction(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);
@@ -62,17 +62,7 @@ int LuaButton::enabled(lua_State * l)
 
 int LuaButton::action(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return actionFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		actionFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		actionFunction = 0;
-	}
-	return 0;
 }
 
 int LuaButton::text(lua_State * l)
@@ -96,7 +86,7 @@ void LuaButton::triggerAction()
 	if(actionFunction)
 	{
 		lua_rawgeti(l, LUA_REGISTRYINDEX, actionFunction);
-		lua_rawgeti(l, LUA_REGISTRYINDEX, UserData);
+		lua_rawgeti(l, LUA_REGISTRYINDEX, owner_ref);
 		if (lua_pcall(l, 1, 0, 0))
 		{
 			ci->Log(CommandInterface::LogError, ByteString(lua_tostring(l, -1)).FromUtf8());

src/lua/LuaButton.h

@@ -13,7 +13,7 @@ class LuaScriptInterface;
 class LuaButton: public LuaComponent
 {
 	ui::Button * button;
-	int actionFunction;
+	LuaComponentCallback actionFunction;
 	void triggerAction();
 	int action(lua_State * l);
 	int text(lua_State * l);

src/lua/LuaCheckbox.cpp

@@ -20,7 +20,7 @@ Luna<LuaCheckbox>::RegType LuaCheckbox::methods[] = {
 
 LuaCheckbox::LuaCheckbox(lua_State * l) :
 	LuaComponent(l),
-	actionFunction(0)
+	actionFunction(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);
@@ -60,17 +60,7 @@ int LuaCheckbox::checked(lua_State * l)
 
 int LuaCheckbox::action(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return actionFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		actionFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		actionFunction = 0;
-	}
-	return 0;
 }
 
 int LuaCheckbox::text(lua_State * l)
@@ -93,7 +83,7 @@ void LuaCheckbox::triggerAction()
 	if(actionFunction)
 	{
 		lua_rawgeti(l, LUA_REGISTRYINDEX, actionFunction);
-		lua_rawgeti(l, LUA_REGISTRYINDEX, UserData);
+		lua_rawgeti(l, LUA_REGISTRYINDEX, owner_ref);
 		lua_pushboolean(l, checkbox->GetChecked());
 		if (lua_pcall(l, 2, 0, 0))
 		{

src/lua/LuaCheckbox.h

@@ -13,7 +13,7 @@ class LuaScriptInterface;
 class LuaCheckbox: public LuaComponent
 {
 	ui::Checkbox * checkbox;
-	int actionFunction;
+	LuaComponentCallback actionFunction;
 	void triggerAction();
 	int action(lua_State * l);
 	int checked(lua_State * l);

src/lua/LuaComponent.cpp

@@ -5,8 +5,17 @@
 #include "LuaScriptInterface.h"
 #include "gui/interface/Component.h"
 
+int LuaComponentCallback::CheckAndAssignArg1()
+{
+	if (lua_type(l, 1) != LUA_TNIL)
+	{
+		luaL_checktype(l, 1, LUA_TFUNCTION);
+	}
+	LuaSmartRef::Assign(1);
+	return 0;
+}
 
-LuaComponent::LuaComponent(lua_State * l)
+LuaComponent::LuaComponent(lua_State * l) : owner_ref(LUA_REFNIL)
 {
 	this->l = l;
 

src/lua/LuaComponent.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "LuaLuna.h"
+#include "LuaSmartRef.h"
 
 namespace ui
 {
@@ -9,6 +10,13 @@ namespace ui
 
 class LuaScriptInterface;
 
+class LuaComponentCallback : public LuaSmartRef
+{
+public:
+	using LuaSmartRef::LuaSmartRef;
+	int CheckAndAssignArg1();
+};
+
 class LuaComponent
 {
 protected:
@@ -19,7 +27,7 @@ protected:
 	int visible(lua_State * l);
 public:
 	LuaScriptInterface * ci;
-	int UserData;
+	int owner_ref;
 
 	ui::Component * GetComponent() { return component; }
 	LuaComponent(lua_State * l);

src/lua/LuaLuna.h

@@ -133,9 +133,6 @@ private:
 		userdataType *ud = static_cast<userdataType*>(lua_newuserdata(L, sizeof(userdataType)));
 		ud->pT = obj;  // store pointer to object in userdata
 
-		obj->UserData = luaL_ref(L, LUA_REGISTRYINDEX);
-		lua_rawgeti(L, LUA_REGISTRYINDEX, obj->UserData);
-
 		luaL_getmetatable(L, T::className);  // lookup metatable in Lua registry
 		lua_setmetatable(L, -2);
 		return 1;  // userdata containing pointer to T object

src/lua/LuaScriptHelper.h

@@ -11,13 +11,16 @@ extern Renderer * luacon_ren;
 extern bool *luacon_currentCommand;
 extern String *luacon_lastError;
 
-extern int *lua_el_func, *lua_el_mode, *lua_gr_func;
+class LuaSmartRef;
+extern int *lua_el_mode;
+extern LuaSmartRef *lua_el_func, *lua_gr_func;
 
 extern int getPartIndex_curIdx;
 extern int tptProperties; //Table for some TPT properties
 extern int tptPropertiesVersion;
 extern int tptElements; //Table for TPT element names
-extern int tptParts, tptPartsMeta, tptElementTransitions, tptPartsCData, tptPartMeta, tptPart, cIndex;
+extern int tptParts, tptPartsMeta, tptElementTransitions, tptPartsCData, tptPartMeta, cIndex;
+extern LuaSmartRef *tptPart;
 
 void luaopen_eventcompat(lua_State *l);
 void luacon_hook(lua_State *L, lua_Debug *ar);

src/lua/LuaScriptInterface.cpp

@@ -62,13 +62,15 @@ bool *luacon_currentCommand;
 String *luacon_lastError;
 String lastCode;
 
-int *lua_el_func, *lua_el_mode, *lua_gr_func;
+int *lua_el_mode;
+LuaSmartRef *lua_el_func, *lua_gr_func;
 
 int getPartIndex_curIdx;
 int tptProperties; //Table for some TPT properties
 int tptPropertiesVersion;
 int tptElements; //Table for TPT element names
-int tptParts, tptPartsMeta, tptElementTransitions, tptPartsCData, tptPartMeta, tptPart, cIndex;
+int tptParts, tptPartsMeta, tptElementTransitions, tptPartsCData, tptPartMeta, cIndex;
+LuaSmartRef *tptPart = nullptr;
 
 int atPanic(lua_State *l)
 {
@@ -261,16 +263,20 @@ tpt.partsdata = nil");
 	lua_setfield(l, tptProperties, "parts");
 
 	lua_newtable(l);
-	tptPart = lua_gettop(l);
+	{
-	lua_newtable(l);
+		int top = lua_gettop(l);
-	tptPartMeta = lua_gettop(l);
+		lua_newtable(l);
-	lua_pushcfunction(l, luacon_partwrite);
+		tptPartMeta = lua_gettop(l);
-	lua_setfield(l, tptPartMeta, "__newindex");
+		lua_pushcfunction(l, luacon_partwrite);
-	lua_pushcfunction(l, luacon_partread);
+		lua_setfield(l, tptPartMeta, "__newindex");
-	lua_setfield(l, tptPartMeta, "__index");
+		lua_pushcfunction(l, luacon_partread);
-	lua_setmetatable(l, tptPart);
+		lua_setfield(l, tptPartMeta, "__index");
+		lua_setmetatable(l, top);
+	}
 
-	tptPart = luaL_ref(l, LUA_REGISTRYINDEX);
+	tptPart = new LuaSmartRef(l);
+	tptPart->Assign(-1);
+	lua_pop(l, 1);
 #endif
 
 	lua_newtable(l);
@@ -314,14 +320,12 @@ tpt.partsdata = nil");
 	}
 	lua_setfield(l, tptProperties, "eltransition");
 
-	lua_el_func = (int*)calloc(PT_NUM, sizeof(int));
+	lua_gr_func_v = std::vector<LuaSmartRef>(PT_NUM, l);
-	lua_el_mode = (int*)calloc(PT_NUM, sizeof(int));
+	lua_gr_func = &lua_gr_func_v[0];
-	lua_gr_func = (int*)calloc(PT_NUM, sizeof(int));
+	lua_el_func_v = std::vector<LuaSmartRef>(PT_NUM, l);
-	for (int i = 0; i < PT_NUM; i++)
+	lua_el_func = &lua_el_func_v[0];
-	{
+	lua_el_mode = new int[PT_NUM];
-		lua_el_mode[i] = 0;
+	std::fill(lua_el_mode, lua_el_mode + PT_NUM, 0);
-		lua_gr_func[i] = 0;
-	}
 
 	//make tpt.* a metatable
 	lua_newtable(l);
@@ -459,47 +463,66 @@ void LuaScriptInterface::initInterfaceAPI()
 
 int LuaScriptInterface::interface_addComponent(lua_State * l)
 {
-	void * luaComponent = NULL;
+	void *opaque = nullptr;
-	ui::Component * component = NULL;
+	LuaComponent *luaComponent = nullptr;
-	if ((luaComponent = Luna<LuaButton>::tryGet(l, 1)))
+	if ((opaque = Luna<LuaButton>::tryGet(l, 1)))
-		component = Luna<LuaButton>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaButton>::get(opaque);
-	else if ((luaComponent = Luna<LuaLabel>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaLabel>::tryGet(l, 1)))
-		component = Luna<LuaLabel>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaLabel>::get(opaque);
-	else if ((luaComponent = Luna<LuaTextbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaTextbox>::tryGet(l, 1)))
-		component = Luna<LuaTextbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaTextbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaCheckbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaCheckbox>::tryGet(l, 1)))
-		component = Luna<LuaCheckbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaCheckbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaSlider>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaSlider>::tryGet(l, 1)))
-		component = Luna<LuaSlider>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaSlider>::get(opaque);
-	else if ((luaComponent = Luna<LuaProgressBar>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaProgressBar>::tryGet(l, 1)))
-		component = Luna<LuaProgressBar>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaProgressBar>::get(opaque);
 	else
 		luaL_typerror(l, 1, "Component");
-	if (luacon_ci->Window && component)
+	if (luacon_ci->Window && luaComponent)
-		luacon_ci->Window->AddComponent(component);
+	{
+		auto ok = luacon_ci->grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef(l)));
+		if (ok.second)
+		{
+			auto it = ok.first;
+			it->second.Assign(1);
+			it->first->owner_ref = it->second;
+		}
+		luacon_ci->Window->AddComponent(luaComponent->GetComponent());
+	}
 	return 0;
 }
 
 int LuaScriptInterface::interface_removeComponent(lua_State * l)
 {
-	void * luaComponent = NULL;
+	void *opaque = nullptr;
-	ui::Component * component = NULL;
+	LuaComponent *luaComponent = nullptr;
-	if ((luaComponent = Luna<LuaButton>::tryGet(l, 1)))
+	if ((opaque = Luna<LuaButton>::tryGet(l, 1)))
-		component = Luna<LuaButton>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaButton>::get(opaque);
-	else if ((luaComponent = Luna<LuaLabel>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaLabel>::tryGet(l, 1)))
-		component = Luna<LuaLabel>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaLabel>::get(opaque);
-	else if ((luaComponent = Luna<LuaTextbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaTextbox>::tryGet(l, 1)))
-		component = Luna<LuaTextbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaTextbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaCheckbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaCheckbox>::tryGet(l, 1)))
-		component = Luna<LuaCheckbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaCheckbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaSlider>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaSlider>::tryGet(l, 1)))
-		component = Luna<LuaSlider>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaSlider>::get(opaque);
-	else if ((luaComponent = Luna<LuaProgressBar>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaProgressBar>::tryGet(l, 1)))
-		component = Luna<LuaProgressBar>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaProgressBar>::get(opaque);
 	else
 		luaL_typerror(l, 1, "Component");
-	if(luacon_ci->Window && component)
+	if(luacon_ci->Window && luaComponent)
+	{
+		ui::Component *component = luaComponent->GetComponent();
 		luacon_ci->Window->RemoveComponent(component);
+		auto it = luacon_ci->grabbed_components.find(luaComponent);
+		if (it != luacon_ci->grabbed_components.end())
+		{
+			it->second.Clear();
+			it->first->owner_ref = it->second;
+			luacon_ci->grabbed_components.erase(it);
+		}
+	}
 	return 0;
 }
 
@@ -2672,12 +2695,14 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "Update");
 		if(lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			lua_el_func[id] = luaL_ref(l, LUA_REGISTRYINDEX);
+			lua_el_func[id].Assign(-1);
+			lua_pop(l, 1);
 			lua_el_mode[id] = 1;
 		}
 		else if(lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
 		{
-			lua_el_func[id] = 0;
+			lua_el_func[id].Clear();
+			lua_pop(l, 1);
 			lua_el_mode[id] = 0;
 			luacon_sim->elements[id].Update = NULL;
 		}
@@ -2687,11 +2712,13 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "Graphics");
 		if(lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			lua_gr_func[id] = luaL_ref(l, LUA_REGISTRYINDEX);
+			lua_gr_func[id].Assign(-1);
+			lua_pop(l, 1);
 		}
 		else if(lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
 		{
-			lua_gr_func[id] = 0;
+			lua_gr_func[id].Clear();
+			lua_pop(l, 1);
 			luacon_sim->elements[id].Graphics = NULL;
 		}
 		else
@@ -2781,12 +2808,11 @@ int LuaScriptInterface::elements_property(lua_State * l)
 				}
 				else
 					lua_el_mode[id] = 1;
-				lua_pushvalue(l, 3);
+				lua_el_func[id].Assign(3);
-				lua_el_func[id] = luaL_ref(l, LUA_REGISTRYINDEX);
 			}
 			else if(lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
 			{
-				lua_el_func[id] = 0;
+				lua_el_func[id].Clear();
 				lua_el_mode[id] = 0;
 				luacon_sim->elements[id].Update = NULL;
 			}
@@ -2795,12 +2821,11 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if(lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				lua_pushvalue(l, 3);
+				lua_gr_func[id].Assign(3);
-				lua_gr_func[id] = luaL_ref(l, LUA_REGISTRYINDEX);
 			}
 			else if(lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
 			{
-				lua_gr_func[id] = 0;
+				lua_gr_func[id].Clear();
 				luacon_sim->elements[id].Graphics = NULL;
 			}
 			luacon_ren->graphicscache[id].isready = 0;
@@ -3709,6 +3734,16 @@ String LuaScriptInterface::FormatCommand(String command)
 }
 
 LuaScriptInterface::~LuaScriptInterface() {
+	delete tptPart;
+	for (auto &component_and_ref : grabbed_components)
+	{
+		luacon_ci->Window->RemoveComponent(component_and_ref.first->GetComponent());
+		component_and_ref.second.Clear();
+		component_and_ref.first->owner_ref = component_and_ref.second;
+	}
+	delete[] lua_el_mode;
+	lua_el_func_v.clear();
+	lua_gr_func_v.clear();
 	lua_close(l);
 	delete legacy;
 }

src/lua/LuaScriptInterface.h

@@ -2,11 +2,14 @@
 #define LUASCRIPTINTERFACE_H_
 
 #include "LuaCompat.h"
+#include "LuaSmartRef.h"
 
 #include "CommandInterface.h"
 #include "lua/LuaEvents.h"
 #include "simulation/Simulation.h"
 
+#include <map>
+
 namespace ui
 {
 	class Window;
@@ -35,6 +38,7 @@ class Tool;
 	lua_setfield(L, -2, #NAME)
 
 class TPTScriptInterface;
+class LuaComponent;
 
 class LuaScriptInterface: public CommandInterface
 {
@@ -177,6 +181,8 @@ class LuaScriptInterface: public CommandInterface
 	static int event_unregister(lua_State * l);
 	static int event_getmodifiers(lua_State * l);
 
+	std::vector<LuaSmartRef> lua_el_func_v, lua_gr_func_v;
+
 public:
 	int tpt_index(lua_State *l);
 	int tpt_newIndex(lua_State *l);
@@ -186,6 +192,7 @@ public:
 
 	ui::Window * Window;
 	lua_State *l;
+	std::map<LuaComponent *, LuaSmartRef> grabbed_components;
 	LuaScriptInterface(GameController * c, GameModel * m);
 
 	void OnTick() override;

src/lua/LuaSlider.cpp

@@ -20,7 +20,7 @@ Luna<LuaSlider>::RegType LuaSlider::methods[] = {
 
 LuaSlider::LuaSlider(lua_State * l) :
 	LuaComponent(l),
-	onValueChangedFunction(0)
+	onValueChangedFunction(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);
@@ -60,17 +60,7 @@ int LuaSlider::steps(lua_State * l)
 
 int LuaSlider::onValueChanged(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onValueChangedFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onValueChangedFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onValueChangedFunction = 0;
-	}
-	return 0;
 }
 
 int LuaSlider::value(lua_State * l)
@@ -93,7 +83,7 @@ void LuaSlider::triggerOnValueChanged()
 	if(onValueChangedFunction)
 	{
 		lua_rawgeti(l, LUA_REGISTRYINDEX, onValueChangedFunction);
-		lua_rawgeti(l, LUA_REGISTRYINDEX, UserData);
+		lua_rawgeti(l, LUA_REGISTRYINDEX, owner_ref);
 		lua_pushinteger(l, slider->GetValue());
 		if (lua_pcall(l, 2, 0, 0))
 		{

src/lua/LuaSlider.h

@@ -13,7 +13,7 @@ class LuaScriptInterface;
 class LuaSlider: public LuaComponent
 {
 	ui::Slider * slider;
-	int onValueChangedFunction;
+	LuaComponentCallback onValueChangedFunction;
 	void triggerOnValueChanged();
 	int onValueChanged(lua_State * l);
 	int steps(lua_State * l);

src/lua/LuaSmartRef.cpp

@@ -0,0 +1,36 @@
+#include "LuaSmartRef.h"
+
+void LuaSmartRef::Clear()
+{
+	luaL_unref(l, LUA_REGISTRYINDEX, ref);
+	ref = LUA_REFNIL;
+}
+
+LuaSmartRef::LuaSmartRef(lua_State *state) :
+	ref(LUA_REFNIL),
+	l(state)
+{
+}
+
+LuaSmartRef::~LuaSmartRef()
+{
+	Clear();
+}
+
+void LuaSmartRef::Assign(int index)
+{
+	Clear();
+	lua_pushvalue(l, index);
+	ref = luaL_ref(l, LUA_REGISTRYINDEX);
+}
+
+LuaSmartRef::operator int() const
+{
+	return ref;
+}
+
+LuaSmartRef::operator bool() const
+{
+	return ref != LUA_REFNIL;
+}
+

src/lua/LuaSmartRef.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "LuaCompat.h"
+
+class LuaSmartRef
+{
+	int ref;
+
+protected:
+	lua_State *l;
+
+public:
+	LuaSmartRef(lua_State *l);
+	~LuaSmartRef();
+	void Assign(int index); // Copies the value before getting reference, stack unchanged.
+	void Clear();
+	operator int() const;
+	operator bool() const;
+};
+

src/lua/LuaTextbox.cpp

@@ -20,7 +20,7 @@ Luna<LuaTextbox>::RegType LuaTextbox::methods[] = {
 
 LuaTextbox::LuaTextbox(lua_State * l) :
 	LuaComponent(l),
-	onTextChangedFunction(0)
+	onTextChangedFunction(l)
 {
 	this->l = l;
 	int posX = luaL_optinteger(l, 1, 0);
@@ -64,17 +64,7 @@ int LuaTextbox::readonly(lua_State * l)
 
 int LuaTextbox::onTextChanged(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onTextChangedFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onTextChangedFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onTextChangedFunction = 0;
-	}
-	return 0;
 }
 
 void LuaTextbox::triggerOnTextChanged()
@@ -82,7 +72,7 @@ void LuaTextbox::triggerOnTextChanged()
 	if(onTextChangedFunction)
 	{
 		lua_rawgeti(l, LUA_REGISTRYINDEX, onTextChangedFunction);
-		lua_rawgeti(l, LUA_REGISTRYINDEX, UserData);
+		lua_rawgeti(l, LUA_REGISTRYINDEX, owner_ref);
 		if (lua_pcall(l, 1, 0, 0))
 		{
 			ci->Log(CommandInterface::LogError, ByteString(lua_tostring(l, -1)).FromUtf8());

src/lua/LuaTextbox.h

@@ -12,7 +12,7 @@ class LuaScriptInterface;
 
 class LuaTextbox: public LuaComponent
 {
-	int onTextChangedFunction;
+	LuaComponentCallback onTextChangedFunction;
 	ui::Textbox * textbox;
 	int text(lua_State * l);
 	int readonly(lua_State * l);

src/lua/LuaWindow.cpp

@@ -39,20 +39,20 @@ Luna<LuaWindow>::RegType LuaWindow::methods[] = {
 };
 
 LuaWindow::LuaWindow(lua_State * l) :
-	onInitializedFunction(0),
+	onInitializedFunction(l),
-	onExitFunction(0),
+	onExitFunction(l),
-	onTickFunction(0),
+	onTickFunction(l),
-	onDrawFunction(0),
+	onDrawFunction(l),
-	onFocusFunction(0),
+	onFocusFunction(l),
-	onBlurFunction(0),
+	onBlurFunction(l),
-	onTryExitFunction(0),
+	onTryExitFunction(l),
-	onTryOkayFunction(0),
+	onTryOkayFunction(l),
-	onMouseMoveFunction(0),
+	onMouseMoveFunction(l),
-	onMouseDownFunction(0),
+	onMouseDownFunction(l),
-	onMouseUpFunction(0),
+	onMouseUpFunction(l),
-	onMouseWheelFunction(0),
+	onMouseWheelFunction(l),
-	onKeyPressFunction(0),
+	onKeyPressFunction(l),
-	onKeyReleaseFunction(0)
+	onKeyReleaseFunction(l)
 {
 	this->l = l;
 	int posX = luaL_optinteger(l, 1, 1);
@@ -107,47 +107,66 @@ LuaWindow::LuaWindow(lua_State * l) :
 
 int LuaWindow::addComponent(lua_State * l)
 {
-	void * luaComponent = NULL;
+	void *opaque = nullptr;
-	ui::Component * component = NULL;
+	LuaComponent *luaComponent = nullptr;
-	if ((luaComponent = Luna<LuaButton>::tryGet(l, 1)))
+	if ((opaque = Luna<LuaButton>::tryGet(l, 1)))
-		component = Luna<LuaButton>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaButton>::get(opaque);
-	else if ((luaComponent = Luna<LuaLabel>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaLabel>::tryGet(l, 1)))
-		component = Luna<LuaLabel>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaLabel>::get(opaque);
-	else if ((luaComponent = Luna<LuaTextbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaTextbox>::tryGet(l, 1)))
-		component = Luna<LuaTextbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaTextbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaCheckbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaCheckbox>::tryGet(l, 1)))
-		component = Luna<LuaCheckbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaCheckbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaSlider>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaSlider>::tryGet(l, 1)))
-		component = Luna<LuaSlider>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaSlider>::get(opaque);
-	else if ((luaComponent = Luna<LuaProgressBar>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaProgressBar>::tryGet(l, 1)))
-		component = Luna<LuaProgressBar>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaProgressBar>::get(opaque);
 	else
 		luaL_typerror(l, 1, "Component");
-	if(component)
+	if (luaComponent)
-		window->AddComponent(component);
+	{
+		auto ok = grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef(l)));
+		if (ok.second)
+		{
+			auto it = ok.first;
+			it->second.Assign(1);
+			it->first->owner_ref = it->second;
+		}
+		window->AddComponent(luaComponent->GetComponent());
+	}
 	return 0;
 }
 
 int LuaWindow::removeComponent(lua_State * l)
 {
-	void * luaComponent = NULL;
+	void *opaque = nullptr;
-	ui::Component * component = NULL;
+	LuaComponent *luaComponent = nullptr;
-	if ((luaComponent = Luna<LuaButton>::tryGet(l, 1)))
+	if ((opaque = Luna<LuaButton>::tryGet(l, 1)))
-		component = Luna<LuaButton>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaButton>::get(opaque);
-	else if ((luaComponent = Luna<LuaLabel>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaLabel>::tryGet(l, 1)))
-		component = Luna<LuaLabel>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaLabel>::get(opaque);
-	else if ((luaComponent = Luna<LuaTextbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaTextbox>::tryGet(l, 1)))
-		component = Luna<LuaTextbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaTextbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaCheckbox>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaCheckbox>::tryGet(l, 1)))
-		component = Luna<LuaCheckbox>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaCheckbox>::get(opaque);
-	else if ((luaComponent = Luna<LuaSlider>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaSlider>::tryGet(l, 1)))
-		component = Luna<LuaSlider>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaSlider>::get(opaque);
-	else if ((luaComponent = Luna<LuaProgressBar>::tryGet(l, 1)))
+	else if ((opaque = Luna<LuaProgressBar>::tryGet(l, 1)))
-		component = Luna<LuaProgressBar>::get(luaComponent)->GetComponent();
+		luaComponent = Luna<LuaProgressBar>::get(opaque);
 	else
 		luaL_typerror(l, 1, "Component");
-	if(component)
+	if (luaComponent)
+	{
+		ui::Component *component = luaComponent->GetComponent();
 		window->RemoveComponent(component);
+		auto it = grabbed_components.find(luaComponent);
+		if (it != grabbed_components.end())
+		{
+			it->second.Clear();
+			it->first->owner_ref = it->second;
+			grabbed_components.erase(it);
+		}
+	}
 	return 0;
 }
 
@@ -395,217 +414,83 @@ void LuaWindow::triggerOnKeyRelease(int key, int scan, bool repeat, bool shift,
 
 int LuaWindow::onInitialized(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onInitializedFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onInitializedFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onInitializedFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onExit(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onExitFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onExitFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onExitFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onTick(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onTickFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onTickFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onTickFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onDraw(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onDrawFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onDrawFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onDrawFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onFocus(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onFocusFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onFocusFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onFocusFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onBlur(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onBlurFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onBlurFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onBlurFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onTryExit(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onTryExitFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onTryExitFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onTryExitFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onTryOkay(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onTryOkayFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onTryOkayFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onTryOkayFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onMouseMove(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onMouseMoveFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onMouseMoveFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onMouseMoveFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onMouseDown(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onMouseDownFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onMouseDownFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onMouseDownFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onMouseUp(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onMouseUpFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onMouseUpFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onMouseUpFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onMouseWheel(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onMouseWheelFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onMouseWheelFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onMouseWheelFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onKeyPress(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onKeyPressFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onKeyPressFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onKeyPressFunction = 0;
-	}
-	return 0;
 }
 
 int LuaWindow::onKeyRelease(lua_State * l)
 {
-	if(lua_type(l, 1) != LUA_TNIL)
+	return onKeyReleaseFunction.CheckAndAssignArg1();
-	{
-		luaL_checktype(l, 1, LUA_TFUNCTION);
-		lua_pushvalue(l, 1);
-		onKeyReleaseFunction = luaL_ref(l, LUA_REGISTRYINDEX);
-	}
-	else
-	{
-		onKeyReleaseFunction = 0;
-	}
-	return 0;
 }
 
 
 LuaWindow::~LuaWindow()
 {
+	for (auto &component_and_ref : grabbed_components)
+	{
+		window->RemoveComponent(component_and_ref.first->GetComponent());
+		component_and_ref.second.Clear();
+		component_and_ref.first->owner_ref = component_and_ref.second;
+	}
 	window->CloseActiveWindow();
 	delete window;
 }

src/lua/LuaWindow.h

@@ -1,6 +1,10 @@
 #pragma once
 
 #include "LuaLuna.h"
+#include "LuaComponent.h"
+#include "LuaSmartRef.h"
+
+#include <map>
 
 namespace ui
 {
@@ -10,20 +14,22 @@ namespace ui
 class LuaScriptInterface;
 class LuaWindow
 {
-	int onInitializedFunction;
+	LuaComponentCallback onInitializedFunction;
-	int onExitFunction;
+	LuaComponentCallback onExitFunction;
-	int onTickFunction;
+	LuaComponentCallback onTickFunction;
-	int onDrawFunction;
+	LuaComponentCallback onDrawFunction;
-	int onFocusFunction;
+	LuaComponentCallback onFocusFunction;
-	int onBlurFunction;
+	LuaComponentCallback onBlurFunction;
-	int onTryExitFunction;
+	LuaComponentCallback onTryExitFunction;
-	int onTryOkayFunction;
+	LuaComponentCallback onTryOkayFunction;
-	int onMouseMoveFunction;
+	LuaComponentCallback onMouseMoveFunction;
-	int onMouseDownFunction;
+	LuaComponentCallback onMouseDownFunction;
-	int onMouseUpFunction;
+	LuaComponentCallback onMouseUpFunction;
-	int onMouseWheelFunction;
+	LuaComponentCallback onMouseWheelFunction;
-	int onKeyPressFunction;
+	LuaComponentCallback onKeyPressFunction;
-	int onKeyReleaseFunction;
+	LuaComponentCallback onKeyReleaseFunction;
+
+	std::map<LuaComponent *, LuaSmartRef> grabbed_components;
 
 	ui::Window * window;
 	lua_State * l;
@@ -65,7 +71,6 @@ class LuaWindow
 
 public:
 	LuaScriptInterface * ci;
-	int UserData;
 	static const char className[];
 	static Luna<LuaWindow>::RegType methods[];