blob: 57e25a00b9d624817d2131b7feaa71afd9b1cb11 [file] [log] [blame]
use core::pin::PinMut;
use futures_core::future::Future;
use futures_core::stream::Stream;
use futures_core::task::{self, Poll};
use pin_utils::unsafe_pinned;
/// A type which converts a `Future` into a `Stream`
/// containing a single element.
#[must_use = "futures do nothing unless polled"]
#[derive(Debug)]
pub struct IntoStream<Fut: Future> {
future: Option<Fut>
}
impl<Fut: Future> IntoStream<Fut> {
unsafe_pinned!(future: Option<Fut>);
pub(super) fn new(future: Fut) -> IntoStream<Fut> {
IntoStream {
future: Some(future)
}
}
}
impl<Fut: Future> Stream for IntoStream<Fut> {
type Item = Fut::Output;
fn poll_next(mut self: PinMut<Self>, cx: &mut task::Context) -> Poll<Option<Self::Item>> {
let v = match self.future().as_pin_mut() {
Some(fut) => {
match fut.poll(cx) {
Poll::Pending => return Poll::Pending,
Poll::Ready(v) => v
}
}
None => return Poll::Ready(None),
};
PinMut::set(self.future(), None);
Poll::Ready(Some(v))
}
}