Struct WeakCell

pub struct WeakCell<T>(/* private fields */);

Version of RefCell that holds a non-owning reference to the managed allocation.

Implementations

impl<T> WeakCell<T>

pub fn new() -> Self

Constructs a new WeakCell<T>, without allocating any memory. Calling WeakCell::upgrade on the return value always gives None.

Examples

use rccell::WeakCell;

let empty: WeakCell<i32> = WeakCell::new();
assert!(empty.upgrade().is_none());

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

Similar to Weak::upgrade. Attempts to upgrade the WeakCell pointer to an RcCell. Returns None if the inner value has been dropped.

Examples

use rccell::RcCell;

let five = RcCell::new(5);

let weak_five = five.downgrade();
let strong_five = weak_five.upgrade();
assert!(strong_five.is_some());

drop(strong_five);
drop(five);
assert!(weak_five.upgrade().is_none());

pub fn strong_count(&self) -> usize

Gets the number of strong (RcCell) pointers pointing to this allocation. If self was created using WeakCell::new, this will return 0.

pub fn weak_count(&self) -> usize

Gets the number of WeakCell pointers pointing to this allocation. If no strong pointers remain, this will return 0.

pub fn ptr_eq(&self, other: &Self) -> bool

Returns true if the two Weaks point to the same allocation, or if both don’t point to any allocation.

Trait Implementations

impl<T> Clone for WeakCell<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> Debug for WeakCell<T>

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

Formats the value using the given formatter.

impl<T: Default> Default for WeakCell<T>

fn default() -> WeakCell<T>

Returns the “default value” for a type.