futures_util/stream/
split.rsuse std::any::Any;
use std::error::Error;
use std::fmt;
use futures_core::{Stream, Poll, Async};
use futures_core::task;
use futures_sink::{ Sink};
use lock::BiLock;
#[must_use = "streams do nothing unless polled"]
#[derive(Debug)]
pub struct SplitStream<S>(BiLock<S>);
impl<S: Sink> SplitStream<S> {
pub fn reunite(self, other: SplitSink<S>) -> Result<S, ReuniteError<S>> {
other.reunite(self)
}
}
impl<S: Stream> Stream for SplitStream<S> {
type Item = S::Item;
type Error = S::Error;
fn poll_next(&mut self, cx: &mut task::Context) -> Poll<Option<S::Item>, S::Error> {
match self.0.poll_lock(cx) {
Async::Ready(mut inner) => inner.poll_next(cx),
Async::Pending => Ok(Async::Pending),
}
}
}
#[allow(bad_style)]
fn SplitSink<S: Sink>(lock: BiLock<S>) -> SplitSink<S> {
SplitSink {
lock,
slot: None,
}
}
#[derive(Debug)]
pub struct SplitSink<S: Sink> {
lock: BiLock<S>,
slot: Option<S::SinkItem>,
}
impl<S: Sink> SplitSink<S> {
pub fn reunite(self, other: SplitStream<S>) -> Result<S, ReuniteError<S>> {
self.lock.reunite(other.0).map_err(|err| {
ReuniteError(SplitSink(err.0), SplitStream(err.1))
})
}
}
impl<S: Sink> Sink for SplitSink<S> {
type SinkItem = S::SinkItem;
type SinkError = S::SinkError;
fn poll_ready(&mut self, cx: &mut task::Context) -> Poll<(), S::SinkError> {
loop {
if self.slot.is_none() {
return Ok(Async::Ready(()));
}
try_ready!(self.poll_flush(cx));
}
}
fn start_send(&mut self, item: S::SinkItem) -> Result<(), S::SinkError> {
self.slot = Some(item);
Ok(())
}
fn poll_flush(&mut self, cx: &mut task::Context) -> Poll<(), S::SinkError> {
match self.lock.poll_lock(cx) {
Async::Ready(mut inner) => {
if self.slot.is_some() {
try_ready!(inner.poll_ready(cx));
inner.start_send(self.slot.take().unwrap())?;
}
inner.poll_flush(cx)
}
Async::Pending => Ok(Async::Pending),
}
}
fn poll_close(&mut self, cx: &mut task::Context) -> Poll<(), S::SinkError> {
match self.lock.poll_lock(cx) {
Async::Ready(mut inner) => {
if self.slot.is_some() {
try_ready!(inner.poll_ready(cx));
inner.start_send(self.slot.take().unwrap())?;
}
inner.poll_close(cx)
}
Async::Pending => Ok(Async::Pending),
}
}
}
pub fn split<S: Stream + Sink>(s: S) -> (SplitSink<S>, SplitStream<S>) {
let (a, b) = BiLock::new(s);
let read = SplitStream(a);
let write = SplitSink(b);
(write, read)
}
pub struct ReuniteError<T: Sink>(pub SplitSink<T>, pub SplitStream<T>);
impl<T: Sink> fmt::Debug for ReuniteError<T> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
fmt.debug_tuple("ReuniteError")
.field(&"...")
.finish()
}
}
impl<T: Sink> fmt::Display for ReuniteError<T> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "tried to reunite a SplitStream and SplitSink that don't form a pair")
}
}
impl<T: Any + Sink> Error for ReuniteError<T> {
fn description(&self) -> &str {
"tried to reunite a SplitStream and SplitSink that don't form a pair"
}
}