Fix LuaSmartRefs acting on dead Lua states

This fixes problems with degenerate cases such as:

	local button
	assert(coroutine.resume(coroutine.create(function()
		button = Button(10, 10, 20, 20)
	end)))
	button:action(function()
		print("hi")
	end)

src/lua/LegacyLuaAPI.cpp

@@ -348,7 +348,7 @@ int luatpt_element_func(lua_State *l)
 		int replace = luaL_optint(l, 3, 0);
 		if (luacon_sim->IsValidElement(element))
 		{
-			lua_el_func[element].Assign(1);
+			lua_el_func[element].Assign(l, 1);
 			if (replace == 2)
 				lua_el_mode[element] = 3; //update before
 			else if (replace)
@@ -428,7 +428,7 @@ int luatpt_graphics_func(lua_State *l)
 		int element = luaL_optint(l, 2, 0);
 		if (luacon_sim->IsValidElement(element))
 		{
-			lua_gr_func[element].Assign(1);
+			lua_gr_func[element].Assign(l, 1);
 			luacon_ren->graphicscache[element].isready = 0;
 			return 0;
 		}

src/lua/LuaButton.cpp

@@ -53,7 +53,7 @@ int LuaButton::enabled(lua_State * l)
 
 int LuaButton::action(lua_State * l)
 {
-	return actionFunction.CheckAndAssignArg1();
+	return actionFunction.CheckAndAssignArg1(l);
 }
 
 int LuaButton::text(lua_State * l)

src/lua/LuaCheckbox.cpp

@@ -51,7 +51,7 @@ int LuaCheckbox::checked(lua_State * l)
 
 int LuaCheckbox::action(lua_State * l)
 {
-	return actionFunction.CheckAndAssignArg1();
+	return actionFunction.CheckAndAssignArg1(l);
 }
 
 int LuaCheckbox::text(lua_State * l)

src/lua/LuaCompat.c

@@ -8,6 +8,15 @@ int luaL_typerror (lua_State *L, int narg, const char *tname)
 	return luaL_argerror(L, narg, msg);
 }
 
+void tpt_lua_setmainthread(lua_State *L)
+{
+}
+
+void tpt_lua_getmainthread(lua_State *L)
+{
+	lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_MAINTHREAD);
+}
+
 #else
 
 // Implement function added in lua 5.2 that we now use
@@ -16,6 +25,17 @@ void lua_pushglobaltable(lua_State *L)
 	lua_pushvalue(L, LUA_GLOBALSINDEX);
 }
 
+void tpt_lua_setmainthread(lua_State *L)
+{
+	lua_pushthread(L);
+	lua_setfield(L, LUA_REGISTRYINDEX, "tpt_lua_mainthread");
+}
+
+void tpt_lua_getmainthread(lua_State *L)
+{
+	lua_getfield(L, LUA_REGISTRYINDEX, "tpt_lua_mainthread");
+}
+
 #endif
 
 // Useful helper function, mainly used for logging

src/lua/LuaCompat.h

@@ -24,6 +24,9 @@ extern "C"
 #include "lua5.1/lualib.h"
 #endif
 
+LUALIB_API void tpt_lua_setmainthread(lua_State *L);
+LUALIB_API void tpt_lua_getmainthread(lua_State *L);
+
 #if LUA_VERSION_NUM >= 502
 LUALIB_API int (luaL_typerror) (lua_State *L, int narg, const char *tname);
 #else

src/lua/LuaComponent.cpp

@@ -7,19 +7,19 @@
 #include "gui/interface/Component.h"
 #include "gui/interface/Window.h"
 
-int LuaComponentCallback::CheckAndAssignArg1()
+int LuaComponentCallback::CheckAndAssignArg1(lua_State *l)
 {
 	if (lua_type(l, 1) != LUA_TNIL)
 	{
 		luaL_checktype(l, 1, LUA_TFUNCTION);
 	}
-	LuaSmartRef::Assign(1);
+	LuaSmartRef::Assign(l, 1);
 	return 0;
 }
 
 LuaComponent::LuaComponent(lua_State * l) : owner_ref(LUA_REFNIL)
 {
-	this->l = l;
+	this->l = l; // I don't get how this doesn't cause crashes later on
 	
 	lua_pushstring(l, "Luacon_ci");
 	lua_gettable(l, LUA_REGISTRYINDEX);

src/lua/LuaComponent.h

@@ -14,7 +14,7 @@ class LuaComponentCallback : public LuaSmartRef
 {
 public:
 	using LuaSmartRef::LuaSmartRef;
-	int CheckAndAssignArg1();
+	int CheckAndAssignArg1(lua_State *l);
 };
 
 class LuaComponent

src/lua/LuaScriptInterface.cpp

@@ -125,6 +125,7 @@ LuaScriptInterface::LuaScriptInterface(GameController * c, GameModel * m):
 
 	//New TPT API
 	l = luaL_newstate();
+	tpt_lua_setmainthread(l);
 	lua_atpanic(l, atPanic);
 	luaL_openlibs(l);
 	luaopen_bit(l);
@@ -291,7 +292,7 @@ tpt.partsdata = nil");
 	}
 
 	tptPart = new LuaSmartRef(l);
-	tptPart->Assign(-1);
+	tptPart->Assign(l, -1);
 	lua_pop(l, 1);
 #endif
 
@@ -522,7 +523,7 @@ int LuaScriptInterface::interface_addComponent(lua_State * l)
 		if (ok.second)
 		{
 			auto it = ok.first;
-			it->second.Assign(1);
+			it->second.Assign(l, 1);
 			it->first->owner_ref = it->second;
 		}
 		luacon_ci->Window->AddComponent(luaComponent->GetComponent());
@@ -2818,7 +2819,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "Update");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			lua_el_func[id].Assign(-1);
+			lua_el_func[id].Assign(l, -1);
 			lua_el_mode[id] = 1;
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
@@ -2832,7 +2833,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "Graphics");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			lua_gr_func[id].Assign(-1);
+			lua_gr_func[id].Assign(l, -1);
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
 		{
@@ -2844,7 +2845,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "Create");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			luaCreateHandlers[id].Assign(-1);
+			luaCreateHandlers[id].Assign(l, -1);
 			luacon_sim->elements[id].Create = luaCreateWrapper;
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
@@ -2857,7 +2858,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "CreateAllowed");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			luaCreateAllowedHandlers[id].Assign(-1);
+			luaCreateAllowedHandlers[id].Assign(l, -1);
 			luacon_sim->elements[id].CreateAllowed = luaCreateAllowedWrapper;
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
@@ -2870,7 +2871,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "ChangeType");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			luaChangeTypeHandlers[id].Assign(-1);
+			luaChangeTypeHandlers[id].Assign(l, -1);
 			luacon_sim->elements[id].ChangeType = luaChangeTypeWrapper;
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
@@ -2883,7 +2884,7 @@ int LuaScriptInterface::elements_element(lua_State * l)
 		lua_getfield(l, -1, "CtypeDraw");
 		if (lua_type(l, -1) == LUA_TFUNCTION)
 		{
-			luaCtypeDrawHandlers[id].Assign(-1);
+			luaCtypeDrawHandlers[id].Assign(l, -1);
 			luacon_sim->elements[id].CtypeDraw = luaCtypeDrawWrapper;
 		}
 		else if (lua_type(l, -1) == LUA_TBOOLEAN && !lua_toboolean(l, -1))
@@ -2998,7 +2999,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 					lua_el_mode[id] = 1; //update after
 					break;
 				}
-				lua_el_func[id].Assign(3);
+				lua_el_func[id].Assign(l, 3);
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
 			{
@@ -3011,7 +3012,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if (lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				lua_gr_func[id].Assign(3);
+				lua_gr_func[id].Assign(l, 3);
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
 			{
@@ -3024,7 +3025,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if (lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				luaCreateHandlers[id].Assign(3);
+				luaCreateHandlers[id].Assign(l, 3);
 				luacon_sim->elements[id].Create = luaCreateWrapper;
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
@@ -3037,7 +3038,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if (lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				luaCreateAllowedHandlers[id].Assign(3);
+				luaCreateAllowedHandlers[id].Assign(l, 3);
 				luacon_sim->elements[id].CreateAllowed = luaCreateAllowedWrapper;
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
@@ -3050,7 +3051,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if (lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				luaChangeTypeHandlers[id].Assign(3);
+				luaChangeTypeHandlers[id].Assign(l, 3);
 				luacon_sim->elements[id].ChangeType = luaChangeTypeWrapper;
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))
@@ -3063,7 +3064,7 @@ int LuaScriptInterface::elements_property(lua_State * l)
 		{
 			if (lua_type(l, 3) == LUA_TFUNCTION)
 			{
-				luaCtypeDrawHandlers[id].Assign(3);
+				luaCtypeDrawHandlers[id].Assign(l, 3);
 				luacon_sim->elements[id].CtypeDraw = luaCtypeDrawWrapper;
 			}
 			else if (lua_type(l, 3) == LUA_TBOOLEAN && !lua_toboolean(l, 3))

src/lua/LuaSlider.cpp

@@ -51,7 +51,7 @@ int LuaSlider::steps(lua_State * l)
 
 int LuaSlider::onValueChanged(lua_State * l)
 {
-	return onValueChangedFunction.CheckAndAssignArg1();
+	return onValueChangedFunction.CheckAndAssignArg1(l);
 }
 
 int LuaSlider::value(lua_State * l)

src/lua/LuaSmartRef.cpp

@@ -3,14 +3,16 @@
 
 void LuaSmartRef::Clear()
 {
-	luaL_unref(l, LUA_REGISTRYINDEX, ref);
+	luaL_unref(rootl, LUA_REGISTRYINDEX, ref);
 	ref = LUA_REFNIL;
 }
 
-LuaSmartRef::LuaSmartRef(lua_State *state) :
+LuaSmartRef::LuaSmartRef(lua_State *l) :
-	ref(LUA_REFNIL),
+	ref(LUA_REFNIL)
-	l(state)
 {
+	tpt_lua_getmainthread(l);
+	rootl = lua_tothread(l, -1);
+	lua_pop(l, 1);
 }
 
 LuaSmartRef::~LuaSmartRef()
@@ -18,20 +20,21 @@ LuaSmartRef::~LuaSmartRef()
 	Clear();
 }
 
-void LuaSmartRef::Assign(int index)
+void LuaSmartRef::Assign(lua_State *l, int index)
 {
+	if (index < 0)
+	{
+		index = lua_gettop(l) + index + 1;
+	}
 	Clear();
 	lua_pushvalue(l, index);
 	ref = luaL_ref(l, LUA_REGISTRYINDEX);
 }
 
-LuaSmartRef::operator int() const
+int LuaSmartRef::Push(lua_State *l)
 {
-	return ref;
+	lua_rawgeti(l, LUA_REGISTRYINDEX, ref);
+	return lua_type(l, -1);
 }
 
-LuaSmartRef::operator bool() const
-{
-	return ref != LUA_REFNIL;
-}
 #endif

src/lua/LuaSmartRef.h

@@ -5,16 +5,22 @@
 class LuaSmartRef
 {
 	int ref;
-
+	lua_State *rootl;
-protected:
-	lua_State *l;
 
 public:
 	LuaSmartRef(lua_State *l);
 	~LuaSmartRef();
-	void Assign(int index); // Copies the value before getting reference, stack unchanged.
+	void Assign(lua_State *l, int index); // Copies the value before getting reference, stack unchanged.
 	void Clear();
-	operator int() const;
+	int Push(lua_State *l); // Always pushes exactly one value, possibly nil.
-	operator bool() const;
-};
 
+	inline operator int() const
+	{
+		return ref;
+	}
+
+	inline operator bool() const
+	{
+		return ref != LUA_REFNIL;
+	}
+};

src/lua/LuaTextbox.cpp

@@ -55,7 +55,7 @@ int LuaTextbox::readonly(lua_State * l)
 
 int LuaTextbox::onTextChanged(lua_State * l)
 {
-	return onTextChangedFunction.CheckAndAssignArg1();
+	return onTextChangedFunction.CheckAndAssignArg1(l);
 }
 
 void LuaTextbox::triggerOnTextChanged()

src/lua/LuaWindow.cpp

@@ -131,7 +131,7 @@ int LuaWindow::addComponent(lua_State * l)
 		if (ok.second)
 		{
 			auto it = ok.first;
-			it->second.Assign(1);
+			it->second.Assign(l, 1);
 			it->first->owner_ref = it->second;
 		}
 		window->AddComponent(luaComponent->GetComponent());
@@ -416,72 +416,72 @@ void LuaWindow::triggerOnKeyRelease(int key, int scan, bool repeat, bool shift,
 
 int LuaWindow::onInitialized(lua_State * l)
 {
-	return onInitializedFunction.CheckAndAssignArg1();
+	return onInitializedFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onExit(lua_State * l)
 {
-	return onExitFunction.CheckAndAssignArg1();
+	return onExitFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onTick(lua_State * l)
 {
-	return onTickFunction.CheckAndAssignArg1();
+	return onTickFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onDraw(lua_State * l)
 {
-	return onDrawFunction.CheckAndAssignArg1();
+	return onDrawFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onFocus(lua_State * l)
 {
-	return onFocusFunction.CheckAndAssignArg1();
+	return onFocusFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onBlur(lua_State * l)
 {
-	return onBlurFunction.CheckAndAssignArg1();
+	return onBlurFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onTryExit(lua_State * l)
 {
-	return onTryExitFunction.CheckAndAssignArg1();
+	return onTryExitFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onTryOkay(lua_State * l)
 {
-	return onTryOkayFunction.CheckAndAssignArg1();
+	return onTryOkayFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onMouseMove(lua_State * l)
 {
-	return onMouseMoveFunction.CheckAndAssignArg1();
+	return onMouseMoveFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onMouseDown(lua_State * l)
 {
-	return onMouseDownFunction.CheckAndAssignArg1();
+	return onMouseDownFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onMouseUp(lua_State * l)
 {
-	return onMouseUpFunction.CheckAndAssignArg1();
+	return onMouseUpFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onMouseWheel(lua_State * l)
 {
-	return onMouseWheelFunction.CheckAndAssignArg1();
+	return onMouseWheelFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onKeyPress(lua_State * l)
 {
-	return onKeyPressFunction.CheckAndAssignArg1();
+	return onKeyPressFunction.CheckAndAssignArg1(l);
 }
 
 int LuaWindow::onKeyRelease(lua_State * l)
 {
-	return onKeyReleaseFunction.CheckAndAssignArg1();
+	return onKeyReleaseFunction.CheckAndAssignArg1(l);
 }