Function par_stream::par_unfold_blocking
source · [−]pub fn par_unfold_blocking<Item, State, P, F>(
params: P,
init: State,
f: F
) -> RecvStream<'static, Item> where
P: Into<ParParams>,
F: 'static + FnMut(usize, State) -> Option<(Item, State)> + Send + Clone,
Item: 'static + Send,
State: 'static + Send + Clone,
Expand description
Produce stream elements from a parallel blocking task.
This function spawns a set of parallel workers. Each worker produces and places
items to an output buffer. The worker pool size and buffer size is determined by
params
.
Each worker receives a copy of initialized state init
, then iteratively calls the function
f(worker_index, State) -> Option<(output, State)>
to update the state and produce an output item.
If a worker receives a None
, the worker with that worker index will halt, but it does not halt
the other workers. The output stream terminates after every worker halts.
use futures::prelude::*;
use par_stream::prelude::*;
use std::sync::{
atomic::{AtomicUsize, Ordering::*},
Arc,
};
let mut vec: Vec<_> =
par_stream::par_unfold_blocking(None, Arc::new(AtomicUsize::new(0)), move |_, counter| {
let output = counter.fetch_add(1, SeqCst);
(output < 1000).then(|| (output, counter))
})
.collect()
.await;
vec.sort();
itertools::assert_equal(vec, 0..1000);