Function SetupCallback

engine/script/src/script.cpp:1937–2014

    }

    bool SetupCallback(LuaCallbackInfo* cbk)
    {
        lua_State* L = cbk->m_L;
        int top = lua_gettop(L);
        if(cbk->m_CallbackInfoRef == LUA_NOREF)
        {
            dmLogWarning("Failed to invoke callback (it was not registered)");
            assert(top == lua_gettop(L));
            return false;
        }

        GetInstance(L);
        // [-1] old instance

        lua_rawgeti(L, LUA_REGISTRYINDEX, cbk->m_ContextTableRef);
        // [-2] old instance
        // [-1] context table

        if (lua_type(L, -1) != LUA_TTABLE)
        {
            lua_pop(L, 2);
            assert(top == lua_gettop(L));
            return false;
        }

        const int context_table_stack_index = lua_gettop(L);

        lua_rawgeti(L, context_table_stack_index, cbk->m_Callback);
        // [-3] old instance
        // [-2] context table
        // [-1] callback

        if (lua_type(L, -1) != LUA_TFUNCTION)
        {
            lua_pop(L, 3);
            assert(top == lua_gettop(L));
            return false;
        }

        lua_rawgeti(L, context_table_stack_index, cbk->m_Self); // Setup self (the script instance)
        // [-4] old instance
        // [-3] context table
        // [-2] callback
        // [-1] self

        if (lua_isnil(L, -1))
        {
            lua_pop(L, 4);
            assert(top == lua_gettop(L));
            return false;
        }

        lua_pushvalue(L, -1);
        // [-5] old instance
        // [-4] context table
        // [-3] callback
        // [-2] self
        // [-1] self