Struct WaitableCell

pub struct WaitableCell<T> { /* private fields */ }

A cell where we can wait (with timeout) for a value to be set

Implementations

impl<T> WaitableCell<T>

pub fn new() -> Self

Creates an empty WaitableCell.

pub fn set(&self, val: impl Into<T>) -> Result<(), T>

Sets a value to the WaitableCell. This method has no effect if the WaitableCell already has a value.

pub fn set_guard_with<R: Into<T>, F: FnOnce() -> R>( &self, f: F, ) -> impl Drop + use<F, T, R>

If the WaitableCell is empty when this guard is dropped, the cell will be set to result of f.

let cell = WaitableCell::<i32>::new();
{
    let _guard = cell.set_guard_with(|| 42);
}
assert_eq!(&42, cell.wait().await);

The operation is a no-op if the cell conbtains a value before the guard is dropped.

let cell = WaitableCell::<i32>::new();
{
    let _guard = cell.set_guard_with(|| 42);
    let _ = cell.set(24);
}
assert_eq!(&24, cell.wait().await);

The function f will always be called, regardless of whether the WaitableCell has a value or not. The WaitableCell is going to be set even in the case of an unwind. In this case, ff the function f panics it will cause an abort, so it’s recommended to avoid any panics in f.

pub async fn wait(&self) -> &T

Wait for the WaitableCell to be set a value.

Trait Implementations

impl<T> Clone for WaitableCell<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Default for WaitableCell<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Send for WaitableCell<T>

impl<T> Sync for WaitableCell<T>