102 lines
2.0 KiB
Rust
102 lines
2.0 KiB
Rust
// Take a look at the license at the top of the repository in the LICENSE file.
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use std::{
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marker::PhantomData,
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rc::{self, Rc},
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sync::{self, Arc},
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};
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// rustdoc-stripper-ignore-next
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/// Trait for generalizing downgrading a strong reference to a weak reference.
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pub trait Downgrade
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where
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Self: Sized,
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{
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// rustdoc-stripper-ignore-next
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/// Weak reference type.
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type Weak;
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// rustdoc-stripper-ignore-next
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/// Downgrade to a weak reference.
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fn downgrade(&self) -> Self::Weak;
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}
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// rustdoc-stripper-ignore-next
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/// Trait for generalizing upgrading a weak reference to a strong reference.
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pub trait Upgrade
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where
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Self: Sized,
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{
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// rustdoc-stripper-ignore-next
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/// Strong reference type.
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type Strong;
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// rustdoc-stripper-ignore-next
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/// Try upgrading a weak reference to a strong reference.
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fn upgrade(&self) -> Option<Self::Strong>;
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}
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impl<T: Downgrade + crate::ObjectType> Upgrade for crate::WeakRef<T> {
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type Strong = T;
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fn upgrade(&self) -> Option<Self::Strong> {
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self.upgrade()
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}
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}
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impl<T> Downgrade for PhantomData<T> {
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type Weak = PhantomData<T>;
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fn downgrade(&self) -> Self::Weak {
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PhantomData
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}
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}
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impl<T: Downgrade> Downgrade for &T {
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type Weak = T::Weak;
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fn downgrade(&self) -> Self::Weak {
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T::downgrade(*self)
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}
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}
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impl<T> Downgrade for Arc<T> {
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type Weak = sync::Weak<T>;
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fn downgrade(&self) -> Self::Weak {
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Arc::downgrade(self)
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}
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}
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impl<T> Upgrade for PhantomData<T> {
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type Strong = PhantomData<T>;
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fn upgrade(&self) -> Option<Self::Strong> {
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Some(PhantomData)
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}
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}
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impl<T> Upgrade for sync::Weak<T> {
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type Strong = Arc<T>;
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fn upgrade(&self) -> Option<Self::Strong> {
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self.upgrade()
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}
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}
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impl<T> Downgrade for Rc<T> {
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type Weak = rc::Weak<T>;
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fn downgrade(&self) -> Self::Weak {
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Rc::downgrade(self)
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}
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}
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impl<T> Upgrade for rc::Weak<T> {
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type Strong = Rc<T>;
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fn upgrade(&self) -> Option<Self::Strong> {
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self.upgrade()
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}
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}
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