Method createWrappedFunction

source/core/StarLua.cpp:1111–1169

}

LuaFunction LuaEngine::createWrappedFunction(LuaDetail::LuaWrappedFunction function) {
  lua_checkstack(m_state, 2);

  auto funcUserdata = (LuaDetail::LuaWrappedFunction*)lua_newuserdata(m_state, sizeof(LuaDetail::LuaWrappedFunction));
  new (funcUserdata) LuaDetail::LuaWrappedFunction(std::move(function));

  lua_rawgeti(m_state, LUA_REGISTRYINDEX, m_wrappedFunctionMetatableRegistryId);
  lua_setmetatable(m_state, -2);

  auto invokeFunction = [](lua_State* state) {
    auto func = (LuaDetail::LuaWrappedFunction*)lua_touserdata(state, lua_upvalueindex(1));
    auto self = luaEnginePtr(state);

    int argumentCount = lua_gettop(state);
    try {
      // For speed, if the argument count is less than some pre-defined
      // value, use a stack array.
      int const MaxArrayArgs = 8;
      LuaDetail::LuaFunctionReturn res;
      if (argumentCount <= MaxArrayArgs) {
        Array<LuaValue, MaxArrayArgs> args;
        for (int i = argumentCount - 1; i >= 0; --i)
          args[i] = self->popLuaValue(state);
        res = (*func)(*self, argumentCount, args.ptr());
      } else {
        List<LuaValue> args(argumentCount);
        for (int i = argumentCount - 1; i >= 0; --i)
          args[i] = self->popLuaValue(state);
        res = (*func)(*self, argumentCount, args.ptr());
      }

      if (auto val = res.ptr<LuaValue>()) {
        self->pushLuaValue(state, *val);
        return 1;
      } else if (auto vec = res.ptr<LuaVariadic<LuaValue>>()) {
        for (auto const& r : *vec)
          self->pushLuaValue(state, r);
        return (int)vec->size();
      } else {
        return 0;
      }
    } catch (LuaInstructionLimitReached const&) {
      lua_pushlightuserdata(state, &s_luaInstructionLimitExceptionKey);
      return lua_error(state);
    } catch (LuaRecursionLimitReached const&) {
      lua_pushlightuserdata(state, &s_luaRecursionLimitExceptionKey);
      return lua_error(state);
    } catch (std::exception const& e) {
      luaL_where(state, 1);
      lua_pushstring(state, printException(e, true).c_str());
      lua_concat(state, 2);
      return lua_error(state);
    }
  };

  lua_pushcclosure(m_state, invokeFunction, 1);

  return LuaFunction(LuaDetail::LuaHandle(RefPtr<LuaEngine>(this), popHandle(m_state)));