1use std::{cell::RefCell, rc::Rc};23#[derive(Clone)]4pub struct FutureWrapper<V>(pub Rc<RefCell<Option<V>>>);5impl<T> FutureWrapper<T> {6 pub fn new() -> Self {7 Self(Rc::new(RefCell::new(None)))8 }9 pub fn fill(self, value: T) {10 assert!(self.0.borrow().is_none(), "wrapper is filled already");11 self.0.borrow_mut().replace(value);12 }13}14impl<T: Clone> FutureWrapper<T> {15 pub fn unwrap(self) -> T {16 self.0.borrow().as_ref().cloned().unwrap()17 }18}1920impl<T> Default for FutureWrapper<T> {21 fn default() -> Self {22 Self::new()23 }24}2526#[macro_export]27macro_rules! rc_fn_helper {28 ($name: ident, $macro_name: ident, $fn: ty) => {29 #[derive(Clone)]30 #[doc = "Function wrapper"]31 pub struct $name(pub std::rc::Rc<$fn>);32 impl std::fmt::Debug for $name {33 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {34 f.debug_struct(std::stringify!($name)).finish()35 }36 }37 impl std::cmp::PartialEq for $name {38 fn eq(&self, other: &$name) -> bool {39 std::ptr::eq(&self.0, &other.0)40 }41 }42 #[doc = "Macro to ease wrapper creation"]43 #[macro_export]44 macro_rules! $macro_name {45 ($val: expr) => {46 $crate::$name(std::rc::Rc::new($val))47 };48 }49 };50}