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