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use std::cell::RefCell;
use jrsonnet_gcmodule::{Cc, Trace};
#[derive(Clone, Trace)]
pub struct Pending<V: Trace + 'static>(pub Cc<RefCell<Option<V>>>);
impl<T: Trace + 'static> Pending<T> {
pub fn new() -> Self {
Self(Cc::new(RefCell::new(None)))
}
pub fn new_filled(v: T) -> Self {
Self(Cc::new(RefCell::new(Some(v))))
}
pub fn fill(self, value: T) {
assert!(self.0.borrow().is_none(), "wrapper is filled already");
self.0.borrow_mut().replace(value);
}
}
impl<T: Clone + Trace + 'static> Pending<T> {
pub fn unwrap(&self) -> T {
self.0.borrow().as_ref().cloned().unwrap()
}
}
impl<T: Trace + 'static> Default for Pending<T> {
fn default() -> Self {
Self::new()
}
}