futures_util/sink/close.rs
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use futures_core::{Poll, Async, Future};
use futures_core::task;
use futures_sink::Sink;
/// Future for the `close` combinator, which polls the sink until all data has
/// been closed.
#[derive(Debug)]
#[must_use = "futures do nothing unless polled"]
pub struct Close<S> {
sink: Option<S>,
}
/// A future that completes when the sink has finished closing.
///
/// The sink itself is returned after closeing is complete.
pub fn new<S: Sink>(sink: S) -> Close<S> {
Close { sink: Some(sink) }
}
impl<S: Sink> Close<S> {
/// Get a shared reference to the inner sink.
/// Returns `None` if the sink has already been closed.
pub fn get_ref(&self) -> Option<&S> {
self.sink.as_ref()
}
/// Get a mutable reference to the inner sink.
/// Returns `None` if the sink has already been closed.
pub fn get_mut(&mut self) -> Option<&mut S> {
self.sink.as_mut()
}
/// Consume the `Close` and return the inner sink.
/// Returns `None` if the sink has already been closed.
pub fn into_inner(self) -> Option<S> {
self.sink
}
}
impl<S: Sink> Future for Close<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 Close after it completed");
if sink.poll_close(cx)?.is_ready() {
Ok(Async::Ready(sink))
} else {
self.sink = Some(sink);
Ok(Async::Pending)
}
}
}