1use crate::Stream;
2use std::pin::Pin;
3use std::task::{Context, Poll};
4use tokio::sync::mpsc::Receiver;
5
6/// A wrapper around [`tokio::sync::mpsc::Receiver`] that implements [`Stream`].
7///
8/// [`tokio::sync::mpsc::Receiver`]: struct@tokio::sync::mpsc::Receiver
9/// [`Stream`]: trait@crate::Stream
10#[derive(Debug)]
11pub struct ReceiverStream<T> {
12 inner: Receiver<T>,
13}
14
15impl<T> ReceiverStream<T> {
16 /// Create a new `ReceiverStream`.
17 pub fn new(recv: Receiver<T>) -> Self {
18 Self { inner: recv }
19 }
20
21 /// Get back the inner `Receiver`.
22 pub fn into_inner(self) -> Receiver<T> {
23 self.inner
24 }
25
26 /// Closes the receiving half of a channel without dropping it.
27 ///
28 /// This prevents any further messages from being sent on the channel while
29 /// still enabling the receiver to drain messages that are buffered. Any
30 /// outstanding [`Permit`] values will still be able to send messages.
31 ///
32 /// To guarantee no messages are dropped, after calling `close()`, you must
33 /// receive all items from the stream until `None` is returned.
34 ///
35 /// [`Permit`]: struct@tokio::sync::mpsc::Permit
36 pub fn close(&mut self) {
37 self.inner.close();
38 }
39}
40
41impl<T> Stream for ReceiverStream<T> {
42 type Item = T;
43
44 fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
45 self.inner.poll_recv(cx)
46 }
47}
48
49impl<T> AsRef<Receiver<T>> for ReceiverStream<T> {
50 fn as_ref(&self) -> &Receiver<T> {
51 &self.inner
52 }
53}
54
55impl<T> AsMut<Receiver<T>> for ReceiverStream<T> {
56 fn as_mut(&mut self) -> &mut Receiver<T> {
57 &mut self.inner
58 }
59}
60
61impl<T> From<Receiver<T>> for ReceiverStream<T> {
62 fn from(recv: Receiver<T>) -> Self {
63 Self::new(recv)
64 }
65}
66