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Add more APIs for UniqueArc

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This commit is contained in:
Frank King 2025-03-03 15:51:05 +08:00
parent 9e5cca5049
commit b542a2bd4b
1 changed files with 250 additions and 5 deletions
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255
library/alloc/src/sync.rs
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@ -4073,7 +4073,7 @@ impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> {
/// reference. Multiple weak pointers can be created, but attempts to upgrade those to strong
/// references will fail unless the `UniqueArc` they point to has been converted into a regular `Arc`.
///
/// Because they are uniquely owned, the contents of a `UniqueArc` can be freely mutated. A common
/// Because it is uniquely owned, the contents of a `UniqueArc` can be freely mutated. A common
/// use case is to have an object be mutable during its initialization phase but then have it become
/// immutable and converted to a normal `Arc`.
///
@ -4084,7 +4084,6 @@ impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> {
/// use std::sync::{Arc, Weak, UniqueArc};
///
/// struct Gadget {
/// #[allow(dead_code)]
/// me: Weak<Gadget>,
/// }
///
@ -4104,7 +4103,6 @@ impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> {
/// previous example, `UniqueArc` allows for more flexibility in the construction of cyclic data,
/// including fallible or async constructors.
#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[derive(Debug)]
pub struct UniqueArc<
T: ?Sized,
#[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
@ -4119,13 +4117,248 @@ pub struct UniqueArc<
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
unsafe impl<T: ?Sized + Sync + Send, A: Allocator + Send> Send for UniqueArc<T, A> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
unsafe impl<T: ?Sized + Sync + Send, A: Allocator + Sync> Sync for UniqueArc<T, A> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
// #[unstable(feature = "coerce_unsized", issue = "18598")]
impl<T: ?Sized + Unsize<U>, U: ?Sized, A: Allocator> CoerceUnsized<UniqueArc<U, A>>
for UniqueArc<T, A>
{
}
// Depends on A = Global
impl<T> UniqueArc<T> {
//#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[unstable(feature = "dispatch_from_dyn", issue = "none")]
impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<UniqueArc<U>> for UniqueArc<T> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + fmt::Display, A: Allocator> fmt::Display for UniqueArc<T, A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&**self, f)
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + fmt::Debug, A: Allocator> fmt::Debug for UniqueArc<T, A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&**self, f)
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> fmt::Pointer for UniqueArc<T, A> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Pointer::fmt(&(&raw const **self), f)
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> borrow::Borrow<T> for UniqueArc<T, A> {
fn borrow(&self) -> &T {
&**self
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> borrow::BorrowMut<T> for UniqueArc<T, A> {
fn borrow_mut(&mut self) -> &mut T {
&mut **self
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> AsRef<T> for UniqueArc<T, A> {
fn as_ref(&self) -> &T {
&**self
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> AsMut<T> for UniqueArc<T, A> {
fn as_mut(&mut self) -> &mut T {
&mut **self
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized, A: Allocator> Unpin for UniqueArc<T, A> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for UniqueArc<T, A> {
/// Equality for two `UniqueArc`s.
///
/// Two `UniqueArc`s are equal if their inner values are equal.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five == UniqueArc::new(5));
/// ```
#[inline]
fn eq(&self, other: &Self) -> bool {
PartialEq::eq(&**self, &**other)
}
/// Inequality for two `UniqueArc`s.
///
/// Two `UniqueArc`s are not equal if their inner values are not equal.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five != UniqueArc::new(6));
/// ```
#[inline]
fn ne(&self, other: &Self) -> bool {
PartialEq::ne(&**self, &**other)
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd for UniqueArc<T, A> {
/// Partial comparison for two `UniqueArc`s.
///
/// The two are compared by calling `partial_cmp()` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
/// use std::cmp::Ordering;
///
/// let five = UniqueArc::new(5);
///
/// assert_eq!(Some(Ordering::Less), five.partial_cmp(&UniqueArc::new(6)));
/// ```
#[inline(always)]
fn partial_cmp(&self, other: &UniqueArc<T, A>) -> Option<Ordering> {
(**self).partial_cmp(&**other)
}
/// Less-than comparison for two `UniqueArc`s.
///
/// The two are compared by calling `<` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five < UniqueArc::new(6));
/// ```
#[inline(always)]
fn lt(&self, other: &UniqueArc<T, A>) -> bool {
**self < **other
}
/// 'Less than or equal to' comparison for two `UniqueArc`s.
///
/// The two are compared by calling `<=` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five <= UniqueArc::new(5));
/// ```
#[inline(always)]
fn le(&self, other: &UniqueArc<T, A>) -> bool {
**self <= **other
}
/// Greater-than comparison for two `UniqueArc`s.
///
/// The two are compared by calling `>` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five > UniqueArc::new(4));
/// ```
#[inline(always)]
fn gt(&self, other: &UniqueArc<T, A>) -> bool {
**self > **other
}
/// 'Greater than or equal to' comparison for two `UniqueArc`s.
///
/// The two are compared by calling `>=` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
///
/// let five = UniqueArc::new(5);
///
/// assert!(five >= UniqueArc::new(5));
/// ```
#[inline(always)]
fn ge(&self, other: &UniqueArc<T, A>) -> bool {
**self >= **other
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + Ord, A: Allocator> Ord for UniqueArc<T, A> {
/// Comparison for two `UniqueArc`s.
///
/// The two are compared by calling `cmp()` on their inner values.
///
/// # Examples
///
/// ```
/// #![feature(unique_rc_arc)]
/// use std::sync::UniqueArc;
/// use std::cmp::Ordering;
///
/// let five = UniqueArc::new(5);
///
/// assert_eq!(Ordering::Less, five.cmp(&UniqueArc::new(6)));
/// ```
#[inline]
fn cmp(&self, other: &UniqueArc<T, A>) -> Ordering {
(**self).cmp(&**other)
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + Eq, A: Allocator> Eq for UniqueArc<T, A> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
impl<T: ?Sized + Hash, A: Allocator> Hash for UniqueArc<T, A> {
fn hash<H: Hasher>(&self, state: &mut H) {
(**self).hash(state);
}
}
impl<T> UniqueArc<T, Global> {
/// Creates a new `UniqueArc`.
///
/// Weak references to this `UniqueArc` can be created with [`UniqueArc::downgrade`]. Upgrading
@ -4134,6 +4367,7 @@ impl<T> UniqueArc<T> {
/// point to the new [`Arc`].
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[must_use]
pub fn new(value: T) -> Self {
Self::new_in(value, Global)
}
@ -4148,6 +4382,8 @@ impl<T, A: Allocator> UniqueArc<T, A> {
/// point to the new [`Arc`].
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[must_use]
// #[unstable(feature = "allocator_api", issue = "32838")]
pub fn new_in(data: T, alloc: A) -> Self {
let (ptr, alloc) = Box::into_unique(Box::new_in(
ArcInner {
@ -4172,6 +4408,7 @@ impl<T: ?Sized, A: Allocator> UniqueArc<T, A> {
/// Any weak references created before this method is called can now be upgraded to strong
/// references.
#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[must_use]
pub fn into_arc(this: Self) -> Arc<T, A> {
let this = ManuallyDrop::new(this);
@ -4195,6 +4432,7 @@ impl<T: ?Sized, A: Allocator + Clone> UniqueArc<T, A> {
/// Attempting to upgrade this weak reference will fail before the `UniqueArc` has been converted
/// to a [`Arc`] using [`UniqueArc::into_arc`].
#[unstable(feature = "unique_rc_arc", issue = "112566")]
#[must_use]
pub fn downgrade(this: &Self) -> Weak<T, A> {
// Using a relaxed ordering is alright here, as knowledge of the
// original reference prevents other threads from erroneously deleting
@ -4236,10 +4474,17 @@ impl<T: ?Sized, A: Allocator> DerefMut for UniqueArc<T, A> {
// SAFETY: This pointer was allocated at creation time so we know it is valid. We know we
// have unique ownership and therefore it's safe to make a mutable reference because
// `UniqueArc` owns the only strong reference to itself.
// We also need to be careful to only create a mutable reference to the `data` field,
// as a mutable reference to the entire `ArcInner` would assert uniqueness over the
// ref count fields too, invalidating any attempt by `Weak`s to access the ref count.
unsafe { &mut (*self.ptr.as_ptr()).data }
}
}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
// #[unstable(feature = "deref_pure_trait", issue = "87121")]
unsafe impl<T: ?Sized, A: Allocator> DerefPure for UniqueArc<T, A> {}
#[unstable(feature = "unique_rc_arc", issue = "112566")]
unsafe impl<#[may_dangle] T: ?Sized, A: Allocator> Drop for UniqueArc<T, A> {
fn drop(&mut self) {