Crate async_promise

async-promise

A simple promise implementation that allows for a single producer to resolve a value to multiple consumers.

Similar to a oneshot channel, but allows for multiple consumers to wait for the value to be resolved, which will be provided as a reference (&T).

Similar to an async OnceCell, but consumers may only await the value, and may not attempt to set it.

Use channel() to create a new promise and resolver pair.

Usage

Add the following to your Cargo.toml:

[dependencies]
async-promise = "..."

Basic usage:

#[tokio::main]
async fn main() {
    let (resolve, promise) = async_promise::channel::<i32>();

    // Resolve the promise.
    resolve.into_resolve(42);

    // Read the value.
    // May be read by multiple consumers.
    let value = promise.wait().await;
    assert_eq!(Some(&42), value);
}

Structs

Promise

A container for a value of type T that may not yet be resolved.

Resolve

The resolve/send half of a promise. Created via channel, and used to resolve the corresponding Promise with a value.

Enums

PromiseError

An error that may occur when trying to get the value from a Promise, see Promise::try_get.

Functions

channel

Creates a new promise and resolver pair.