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use futures_core::{Poll, Async, Future};
use futures_core::task;
use futures_sink::Sink;
#[derive(Debug)]
#[must_use = "futures do nothing unless polled"]
pub struct Flush<S> {
sink: Option<S>,
}
pub fn new<S: Sink>(sink: S) -> Flush<S> {
Flush { sink: Some(sink) }
}
impl<S: Sink> Flush<S> {
pub fn get_ref(&self) -> Option<&S> {
self.sink.as_ref()
}
pub fn get_mut(&mut self) -> Option<&mut S> {
self.sink.as_mut()
}
pub fn into_inner(self) -> Option<S> {
self.sink
}
}
impl<S: Sink> Future for Flush<S> {
type Item = S;
type Error = S::SinkError;
fn poll(&mut self, cx: &mut task::Context) -> Poll<S, S::SinkError> {
let mut sink = self.sink.take().expect("Attempted to poll Flush after it completed");
if sink.poll_flush(cx)?.is_ready() {
Ok(Async::Ready(sink))
} else {
self.sink = Some(sink);
Ok(Async::Pending)
}
}
}