blob: c3dda9dad5e90391cb03dca10eb46f536c798acf [file] [log] [blame]
use futures_core::future::Future;
use futures_core::stream::Stream;
use futures_core::task::{self, Poll};
use pin_utils::{unsafe_pinned, unsafe_unpinned};
use std::marker::Unpin;
use std::mem::{self, PinMut};
use std::prelude::v1::*;
/// A future which collects all of the values of a stream into a vector.
///
/// This future is created by the `Stream::collect` method.
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct Collect<St, C> where St: Stream {
stream: St,
collection: C,
}
impl<St: Unpin + Stream, C> Unpin for Collect<St, C> {}
impl<St: Stream, C: Default> Collect<St, C> {
unsafe_pinned!(stream: St);
unsafe_unpinned!(collection: C);
fn finish(mut self: PinMut<Self>) -> C {
mem::replace(self.collection(), Default::default())
}
pub(super) fn new(stream: St) -> Collect<St, C> {
Collect {
stream,
collection: Default::default(),
}
}
}
impl<St, C> Future for Collect<St, C>
where St: Stream,
C: Default + Extend<St:: Item>
{
type Output = C;
fn poll(mut self: PinMut<Self>, cx: &mut task::Context) -> Poll<C> {
loop {
match ready!(self.stream().poll_next(cx)) {
Some(e) => self.collection().extend(Some(e)),
None => return Poll::Ready(self.finish()),
}
}
}
}