Struct OneshotNotifier 

pub(crate) struct OneshotNotifier<T = ()> {
    context: &'static str,
    sender: Arc<Mutex<Option<Sender<T>>>>,
}

A helper type to wait for a notification that can occur only one time.

OneshotNotifier::listen() must be called to initialize it and get a receiver. The receiver must then be .awaited and the future will resolve when it is notified.

The receiver will receive a signal the first time that OneshotNotifier::notify_value() is called. Further calls to this function will be noops until a new receiver is created.The value to return must implement Default, as this is the value that will be sent to the receiver when the notifier is dropped before a value is notified.

This notifier can be cloned freely and moved between threads.

It is also possible to share this notifier between tasks to make sure that a single task is running at a time. If OneshotNotifier::listen() is called while there is already a receiver waiting, it will be notified as if the notifier was dropped.

Fields

context: &'static str

The context used to identify the notifier in logs.

sender: Arc<Mutex<Option<Sender<T>>>>

The sender for the notification signal.

Implementations

impl<T> OneshotNotifier<T>

pub(crate) fn new(context: &'static str) -> Self

Get a new OneshotNotifier for the given context.

impl<T> OneshotNotifier<T>

where T: Default + Send + 'static,

pub(crate) fn listen(&self) -> OneshotNotifierReceiver<T>

Initialize this OneshotNotifier and get a receiver.

pub(crate) fn notify_value(&self, value: T)

Notify the receiver with the given value, if any receiver is still listening.

pub(crate) fn notify(&self)

Notify the receiver with the default value, if any receiver is still listening.

Trait Implementations

impl<T: Clone> Clone for OneshotNotifier<T>

fn clone(&self) -> OneshotNotifier<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for OneshotNotifier<T>

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

Formats the value using the given formatter.