1use std::cell::RefCell;23use jrsonnet_gcmodule::{Cc, Trace};45#[derive(Clone, Trace)]6pub struct Pending<V: Trace + 'static>(pub Cc<RefCell<Option<V>>>);7impl<T: Trace + 'static> Pending<T> {8 pub fn new() -> Self {9 Self(Cc::new(RefCell::new(None)))10 }11 pub fn new_filled(v: T) -> Self {12 Self(Cc::new(RefCell::new(Some(v))))13 }14 15 16 pub fn fill(self, value: T) {17 assert!(self.0.borrow().is_none(), "wrapper is filled already");18 self.0.borrow_mut().replace(value);19 }20}21impl<T: Clone + Trace + 'static> Pending<T> {22 23 24 pub fn unwrap(&self) -> T {25 self.0.borrow().as_ref().cloned().unwrap()26 }27}2829impl<T: Trace + 'static> Default for Pending<T> {30 fn default() -> Self {31 Self::new()32 }33}