Trait WeakRef 

pub trait WeakRef {
    type Strong: StrongRef<Weak = Self>;

    // Required method
    fn upgrade(&self) -> Option<Self::Strong>;

    // Provided method
    fn is_expired(&self) -> bool { ... }
}

A trait for weak references.

Required Associated Types

type Strong: StrongRef<Weak = Self>

The type of the strong reference.

For example, for std::rc::Weak<T>, this will be std::rc::Rc<T>.

Required Methods

fn upgrade(&self) -> Option<Self::Strong>

Acquires a strong reference from a weak reference.

This is usually implemented by an upgrade method.

Provided Methods

fn is_expired(&self) -> bool

Is the given weak element expired?

The default implemention checks whether a strong reference can be obtained via upgrade.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<T: ?Sized> WeakRef for Weak<T>

type Strong = Rc<T>

fn upgrade(&self) -> Option<Self::Strong>

fn is_expired(&self) -> bool

impl<T: ?Sized> WeakRef for Weak<T>

type Strong = Arc<T>

fn upgrade(&self) -> Option<Self::Strong>

fn is_expired(&self) -> bool

Implementors