Function futures::collect

pub fn collect<I>(i: I) -> Collect<I> where I: IntoIterator, I::Item: IntoFuture

Creates a future which represents a collection of the results of the futures given.

The returned future will execute each underlying future one at a time, collecting the results into a destination Vec<T>. If any future returns an error then all other futures will be canceled and an error will be returned immediately. If all futures complete successfully, however, then the returned future will succeed with a Vec of all the successful results.

Note that this function does not attempt to execute each future in parallel, they are all executed in sequence.

Examples

use futures::*;

let f = collect(vec![
    finished::<u32, u32>(1),
    finished::<u32, u32>(2),
    finished::<u32, u32>(3),
]);
let f = f.map(|x| {
    assert_eq!(x, [1, 2, 3]);
});

let f = collect(vec![
    finished::<u32, u32>(1).boxed(),
    failed::<u32, u32>(2).boxed(),
    finished::<u32, u32>(3).boxed(),
]);
let f = f.then(|x| {
    assert_eq!(x, Err(2));
    x
});