Struct ArcShiftWeak

pub struct ArcShiftWeak<T: ?Sized> { /* private fields */ }

ArcShiftWeak is a way to keep a pointer to an object without preventing said object from being deallocated. This can be useful when creating cyclic data structure, to avoid memory leaks.

let original_instance = ArcShift::new("test");
let light_instance = ArcShift::downgrade(&original_instance);
let mut instance = light_instance.upgrade().unwrap();
println!("Value: {:?}", instance.get());

WARNING! Because of implementation reasons, each instance of ArcShiftWeak will claim a memory equal to size_of::<T> (plus 5 words), even if the value inside it has freed, and even if all other instances of ArcShift/ArcShiftWeak have been dropped. If this limitation is unacceptable, consider using ArcShiftWeak<Box<T>> as your datatype, or possibly using a different crate.

Implementations

impl<T: ?Sized> ArcShiftWeak<T>

pub fn upgrade(&self) -> Option<ArcShift<T>>

Upgrade this ArcShiftWeak instance to a full ArcShift. This is required to be able to access any stored value. If the ArcShift instance has no value (because the last ArcShift instance had been deallocated), this method returns None.

Trait Implementations

impl<T: ?Sized> Clone for ArcShiftWeak<T>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for ArcShiftWeak<T>

where T: Debug + ?Sized,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: ?Sized> Drop for ArcShiftWeak<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: Sync + Send + ?Sized> Send for ArcShiftWeak<T>

SAFETY: If T is Sync and Send, ArcShiftWeak<T> can also be Send

impl<T: Sync + Send + ?Sized> Sync for ArcShiftWeak<T>

SAFETY: If T is Sync and Send, ArcShiftWeak<T> can also be Sync