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use std::{
pin::Pin,
sync::Arc,
task::{Context, Poll},
};
use async_broadcast::Receiver as ActiveReceiver;
use futures_core::{ready, stream};
use futures_util::stream::FusedStream;
use ordered_stream::{OrderedStream, PollResult};
use static_assertions::assert_impl_all;
use crate::{
async_channel::Receiver, Connection, ConnectionInner, Error, Message, MessageSequence, Result,
};
#[derive(Clone, Debug)]
#[must_use = "streams do nothing unless polled"]
pub struct MessageStream {
conn_inner: Arc<ConnectionInner>,
msg_receiver: ActiveReceiver<Arc<Message>>,
error_receiver: Receiver<Error>,
last_seq: MessageSequence,
}
assert_impl_all!(MessageStream: Send, Sync, Unpin);
impl stream::Stream for MessageStream {
type Item = Result<Arc<Message>>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let this = self.get_mut();
if !this.msg_receiver.is_terminated() {
if let Some(msg) = ready!(Pin::new(&mut this.msg_receiver).poll_next(cx)) {
this.last_seq = msg.recv_position();
return Poll::Ready(Some(Ok(msg)));
}
}
Pin::new(&mut this.error_receiver)
.poll_next(cx)
.map(|v| v.map(Err))
}
}
impl OrderedStream for MessageStream {
type Data = Result<Arc<Message>>;
type Ordering = MessageSequence;
fn poll_next_before(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
before: Option<&Self::Ordering>,
) -> Poll<PollResult<Self::Ordering, Self::Data>> {
let this = self.get_mut();
if let Some(before) = before {
if this.last_seq >= *before {
return Poll::Ready(PollResult::NoneBefore);
}
}
if let Some(msg) = ready!(stream::Stream::poll_next(Pin::new(this), cx)) {
Poll::Ready(PollResult::Item {
data: msg,
ordering: this.last_seq,
})
} else {
Poll::Ready(PollResult::Terminated)
}
}
}
impl FusedStream for MessageStream {
fn is_terminated(&self) -> bool {
self.msg_receiver.is_terminated() && self.error_receiver.is_terminated()
}
}
impl From<Connection> for MessageStream {
fn from(conn: Connection) -> Self {
let conn_inner = conn.inner.clone();
let msg_receiver = conn.msg_receiver.activate();
let error_receiver = conn.error_receiver;
Self {
conn_inner,
msg_receiver,
error_receiver,
last_seq: Default::default(),
}
}
}
impl From<&Connection> for MessageStream {
fn from(conn: &Connection) -> Self {
Self::from(conn.clone())
}
}
impl From<MessageStream> for Connection {
fn from(stream: MessageStream) -> Connection {
Connection {
msg_receiver: stream.msg_receiver.deactivate(),
error_receiver: stream.error_receiver,
inner: stream.conn_inner,
}
}
}