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tidy up

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This commit is contained in:
DPC 2020-08-15 03:16:20 +02:00
parent fdc2d1f499
commit 9ad17b9ca7
1 changed files with 23 additions and 23 deletions
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46
library/alloc/src/sync.rs
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@ -329,25 +329,25 @@ impl<T> Arc<T> {
}
/// Constructs a new `Arc<T>` using a weak reference to itself. Attempting
/// to upgrade the weak reference before this function returns will result
/// in a `None` value. However, the weak reference may be cloned freely and
/// stored for use at a later time.
///
/// # Examples
/// ```
/// #![feature(arc_new_cyclic)]
/// #![allow(dead_code)]
///
/// use std::sync::{Arc, Weak};
///
/// struct Foo {
/// me: Weak<Foo>,
/// }
///
/// let foo = Arc::new_cyclic(|me| Foo {
/// me: me.clone(),
/// });
/// ```
/// to upgrade the weak reference before this function returns will result
/// in a `None` value. However, the weak reference may be cloned freely and
/// stored for use at a later time.
///
/// # Examples
/// ```
/// #![feature(arc_new_cyclic)]
/// #![allow(dead_code)]
///
/// use std::sync::{Arc, Weak};
///
/// struct Foo {
/// me: Weak<Foo>,
/// }
///
/// let foo = Arc::new_cyclic(|me| Foo {
/// me: me.clone(),
/// });
/// ```
#[inline]
#[unstable(feature = "arc_new_cyclic", issue = "none")]
pub fn new_cyclic(data_fn: impl FnOnce(&Weak<T>) -> T) -> Arc<T> {
@ -358,7 +358,7 @@ impl<T> Arc<T> {
weak: atomic::AtomicUsize::new(1),
data: mem::MaybeUninit::<T>::uninit(),
})
.into();
.into();
let init_ptr: NonNull<ArcInner<T>> = uninit_ptr.cast();
let weak = Weak { ptr: init_ptr };
@ -1683,9 +1683,9 @@ impl<T: ?Sized> Weak<T> {
}
// Relaxed is fine for the failure case because we don't have any expectations about the new state.
// Acquire is necessary for the success case to synchronise with `Arc::new_cyclic`, when the inner
// value can be initialized after `Weak` references have already been created. In that case, we
// expect to observe the fully initialized value.
// Acquire is necessary for the success case to synchronise with `Arc::new_cyclic`, when the inner
// value can be initialized after `Weak` references have already been created. In that case, we
// expect to observe the fully initialized value.
match inner.strong.compare_exchange_weak(n, n + 1, Acquire, Relaxed) {
Ok(_) => return Some(Arc::from_inner(self.ptr)), // null checked above
Err(old) => n = old,