Struct Pool 

pub struct Pool(/* private fields */);

Available on crate feature coroutine only.

A pool for limiting async tasks

The pool is not to be used as a thread pool. It is used more as a “limiter” to ensure we only fire a limited number of resource-intensive tasks. The IO work for those tasks are drived by a single monitoring thread.

This is good for things like spawning compiler processes where the IO between child and parent processes are low, but not good for spawning CPU-bound tasks. Use something like rayon for CPU parallelism.

The pool can be cloned and shared between threads. Dropping the pool will not cause the spawned tasks to be either joined to canceled. You must use individual handles to join them.

This is constructed with cu::co::pool, since it’s shorter than cu::co::Pool::new(n).

Implementations

impl Pool

pub fn add_permits(&self, n: usize)

Add N permits to the underlying semaphore

pub fn forget_permits(&self, n: usize) -> usize

Remove N permits from the underlying semaphore, return the actual number removed.

pub fn spawn<F>(&self, future: F) -> Handle<F::Output>

where F: Future + Send + 'static, F::Output: Send + 'static,

Spawn a task using the background runtime

The task is spawned with cu::co::spawn, and will only start being executed when the pool has availability (permits).

pub fn spawn_blocking<F, R>(&self, f: F) -> Handle<Result<R>>

where F: FnOnce() -> R + Send + 'static, R: Send + 'static,

Available on crate feature coroutine-heavy only.

Spawn a synchronous task using the background runtime

A wait task will be spawned with cu::co::spawn, and the function will only be spawned with cu::co::spawn_blocking when the pool has availability (permits).

Performance

Even though it’s never recommended to block the async runtime, if the synchronous work is short, it might be more performant to use spawn instead.

Trait Implementations

impl Clone for Pool

fn clone(&self) -> Pool

Returns a duplicate of the value.

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

Performs copy-assignment from source.