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use std::marker::PhantomData;
use std::sync::atomic::{AtomicPtr, Ordering};
/// This is essentially an `AtomicPtr` but is guaranteed to always be valid
pub struct AtomicRef<T: 'static>(AtomicPtr<T>, PhantomData<&'static T>);
impl<T: 'static> AtomicRef<T> {
pub const fn new(initial: &'static T) -> AtomicRef<T> {
AtomicRef(AtomicPtr::new(initial as *const T as *mut T), PhantomData)
}
pub fn swap(&self, new: &'static T) -> &'static T {
// We never allow storing anything but a `'static` reference so it's safe to
// return it for the same.
unsafe { &*self.0.swap(new as *const T as *mut T, Ordering::SeqCst) }
}
}
impl<T: 'static> std::ops::Deref for AtomicRef<T> {
type Target = T;
fn deref(&self) -> &Self::Target {
// We never allow storing anything but a `'static` reference so it's safe to lend
// it out for any amount of time.
unsafe { &*self.0.load(Ordering::SeqCst) }
}
}
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