rustc_data_structures/
atomic_ref.rs

1use std::marker::PhantomData;
2use std::sync::atomic::{AtomicPtr, Ordering};
3
4/// This is essentially an `AtomicPtr` but is guaranteed to always be valid
5pub struct AtomicRef<T: 'static>(AtomicPtr<T>, PhantomData<&'static T>);
6
7impl<T: 'static> AtomicRef<T> {
8    pub const fn new(initial: &'static T) -> AtomicRef<T> {
9        AtomicRef(AtomicPtr::new(initial as *const T as *mut T), PhantomData)
10    }
11
12    pub fn swap(&self, new: &'static T) -> &'static T {
13        // We never allow storing anything but a `'static` reference so it's safe to
14        // return it for the same.
15        unsafe { &*self.0.swap(new as *const T as *mut T, Ordering::SeqCst) }
16    }
17}
18
19impl<T: 'static> std::ops::Deref for AtomicRef<T> {
20    type Target = T;
21    fn deref(&self) -> &Self::Target {
22        // We never allow storing anything but a `'static` reference so it's safe to lend
23        // it out for any amount of time.
24        unsafe { &*self.0.load(Ordering::SeqCst) }
25    }
26}
rustc_data_structures/atomic_ref.rs

rustc_data_structures/
atomic_ref.rs
