1 use std::io;
2
3 use futures::{Async, Future, Poll};
4
5 use AsyncWrite;
6
7 /// A future used to fully flush an I/O object.
8 ///
9 /// Resolves to the underlying I/O object once the flush operation is complete.
10 ///
11 /// Created by the [`flush`] function.
12 ///
13 /// [`flush`]: fn.flush.html
14 #[derive(Debug)]
15 pub struct Flush<A> {
16 a: Option<A>,
17 }
18
19 /// Creates a future which will entirely flush an I/O object and then yield the
20 /// object itself.
21 ///
22 /// This function will consume the object provided if an error happens, and
23 /// otherwise it will repeatedly call `flush` until it sees `Ok(())`, scheduling
24 /// a retry if `WouldBlock` is seen along the way.
flush<A>(a: A) -> Flush<A> where A: AsyncWrite,25 pub fn flush<A>(a: A) -> Flush<A>
26 where
27 A: AsyncWrite,
28 {
29 Flush { a: Some(a) }
30 }
31
32 impl<A> Future for Flush<A>
33 where
34 A: AsyncWrite,
35 {
36 type Item = A;
37 type Error = io::Error;
38
poll(&mut self) -> Poll<A, io::Error>39 fn poll(&mut self) -> Poll<A, io::Error> {
40 try_ready!(self.a.as_mut().unwrap().poll_flush());
41 Ok(Async::Ready(self.a.take().unwrap()))
42 }
43 }
44