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feat: Add stream::delay

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k-nasa 2019-11-27 14:26:04 +09:00
parent 3b055f364e
commit 635c592950
1 changed files with 17 additions and 13 deletions
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22
src/stream/stream/delay.rs
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@ -2,22 +2,24 @@ use std::future::Future;
use std::pin::Pin; use std::pin::Pin;
use std::time::Duration; use std::time::Duration;
use pin_project_lite::pin_project;
use crate::stream::Stream; use crate::stream::Stream;
use crate::task::{Context, Poll}; use crate::task::{Context, Poll};
pin_project! {
#[doc(hidden)] #[doc(hidden)]
#[allow(missing_debug_implementations)] #[allow(missing_debug_implementations)]
pub struct Delay<S> { pub struct Delay<S> {
#[pin]
stream: S, stream: S,
#[pin]
delay: futures_timer::Delay, delay: futures_timer::Delay,
delay_done: bool, delay_done: bool,
} }
}
impl<S> Delay<S> { impl<S> Delay<S> {
pin_utils::unsafe_pinned!(stream: S);
pin_utils::unsafe_pinned!(delay: futures_timer::Delay);
pin_utils::unsafe_unpinned!(delay_done: bool);
pub(super) fn new(stream: S, dur: Duration) -> Self { pub(super) fn new(stream: S, dur: Duration) -> Self {
Delay { Delay {
stream, stream,
@ -33,12 +35,14 @@ where
{ {
type Item = S::Item; type Item = S::Item;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> { fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
if !self.delay_done { let this = self.project();
futures_core::ready!(self.as_mut().delay().poll(cx));
*self.as_mut().delay_done() = true; if !*this.delay_done {
futures_core::ready!(this.delay.poll(cx));
*this.delay_done = true;
} }
self.as_mut().stream().poll_next(cx) this.stream.poll_next(cx)
} }
} }