refactor(lua): generate separate environments for script

core/src/datatypes/signal.cpp

@@ -38,25 +38,6 @@ LuaSignalConnection::~LuaSignalConnection() {
     luaL_unref(state, LUA_REGISTRYINDEX, thread);
 }
 
-#if 0
-static void stackdump(lua_State* L) {
-    printf("%d\n", lua_gettop(L));
-    fflush(stdout);
-    lua_getfield(L, LUA_GLOBALSINDEX, "tostring");
-    for (int i = lua_gettop(L)-1; i >= 1; i--) {
-        lua_pushvalue(L, -1);
-        lua_pushvalue(L, i);
-        lua_call(L, 1, 1);
-        const char* str = lua_tostring(L, -1);
-        lua_pop(L, 1);
-        printf("%s: %s\n", lua_typename(L, lua_type(L, i)), str);
-    }
-    lua_pop(L, 1);
-    printf("\n\n");
-    fflush(stdout);
-}
-#endif
-
 void LuaSignalConnection::Call(std::vector<Variant> args) {
     lua_State* thread = lua_newthread(state);
 

core/src/objects/script.cpp

@@ -31,13 +31,22 @@ void Script::Run() {
     this->thread = lua_newthread(L);
     lua_State* Lt = thread;
 
+    lua_pushthread(Lt); // Push thread for later*
+
     // Initialize script globals
-    lua_getglobal(Lt, "_G");
+    scriptContext->NewEnvironment(Lt); // Pushes envtable, metatable
+
+    // Set script in metatable source
+    InstanceRef(shared_from_this()).PushLuaValue(Lt);
+    lua_setfield(Lt, -2, "source");
+
+    lua_pop(Lt, 1); // Pop metatable
 
     InstanceRef(shared_from_this()).PushLuaValue(Lt);
     lua_setfield(Lt, -2, "script");
 
-    lua_pop(Lt, 1); // _G
+    lua_setfenv(Lt, -2); // *Set env of current thread
+    lua_pop(Lt, 1); // Pop thread
 
     // Push wrapper as thread function
     lua_getfield(Lt, LUA_REGISTRYINDEX, "LuaPCallWrapper");

core/src/objects/service/script/scriptcontext.cpp

@@ -17,13 +17,14 @@ int g_wait(lua_State*);
 int g_delay(lua_State*);
 static int g_print(lua_State*);
 static int g_require(lua_State*);
-static const struct luaL_Reg luaglobals [] = {
+static const luaL_Reg luaglobals [] = {
     {"print", g_print},
     {"require", g_require},
     {NULL, NULL} /* end of array */
 };
 
 std::string unsafe_globals[] = {
+    // Todo implement our own "safe" setfenv/getfenv
     "loadfile", "loadstring", "load", "dofile", "getfenv", "setfenv"
 };
 
@@ -161,6 +162,27 @@ void ScriptContext::RunSleepingThreads() {
         schedTime = tu_clock_micros() - startTime;
 }
 
+void ScriptContext::NewEnvironment(lua_State* L) {
+    lua_newtable(L); // Env table
+    lua_newtable(L); // Metatable
+
+    // Push __index
+    lua_pushvalue(L, LUA_GLOBALSINDEX);
+    lua_setfield(L, -2, "__index");
+
+    // Push __metatable
+    lua_pushstring(L, "metatable is locked");
+    lua_setfield(L, -2, "__metatable");
+
+    // Copy metatable and set the env table's metatable
+    lua_pushvalue(L, -1);
+    lua_setmetatable(L, -3);
+
+    // Remainder on stack:
+    // 1. Env table
+    // 2. Metatable
+}
+
 // https://www.lua.org/source/5.1/lbaselib.c.html
 static int g_print(lua_State* L) {
     std::string buf;

core/src/objects/service/script/scriptcontext.h

@@ -32,5 +32,8 @@ public:
     void PushThreadSleep(lua_State* thread, float delay);
     void RunSleepingThreads();
 
+    // Generates an environment with a metatable and pushes it both the env table and metatable in order onto the stack
+    void NewEnvironment(lua_State* state);
+
     static inline std::shared_ptr<Instance> Create() { return std::make_shared<ScriptContext>(); };
 };