proxmox-backup/src/client/pipe_to_stream.rs

71 lines
2.2 KiB
Rust

// Implement simple flow control for h2 client
//
// See also: hyper/src/proto/h2/mod.rs
use std::pin::Pin;
use std::task::{Context, Poll};
use bytes::Bytes;
use failure::*;
use futures::{ready, Future};
use h2::SendStream;
pub struct PipeToSendStream {
body_tx: SendStream<Bytes>,
data: Option<Bytes>,
}
impl PipeToSendStream {
pub fn new(data: Bytes, tx: SendStream<Bytes>) -> PipeToSendStream {
PipeToSendStream {
body_tx: tx,
data: Some(data),
}
}
}
impl Future for PipeToSendStream {
type Output = Result<(), Error>;
fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
let this = self.get_mut();
if this.data != None {
// just reserve 1 byte to make sure there's some
// capacity available. h2 will handle the capacity
// management for the actual body chunk.
this.body_tx.reserve_capacity(1);
if this.body_tx.capacity() == 0 {
loop {
match ready!(this.body_tx.poll_capacity(cx)) {
Some(Err(err)) => return Poll::Ready(Err(Error::from(err))),
Some(Ok(0)) => {}
Some(Ok(_)) => break,
None => return Poll::Ready(Err(format_err!("protocol canceled"))),
}
}
} else if let Poll::Ready(reset) = this.body_tx.poll_reset(cx) {
return Poll::Ready(Err(match reset {
Ok(reason) => format_err!("stream received RST_STREAM: {:?}", reason),
Err(err) => Error::from(err),
}));
}
this.body_tx
.send_data(this.data.take().unwrap(), true)
.map_err(Error::from)?;
Poll::Ready(Ok(()))
} else {
if let Poll::Ready(reset) = this.body_tx.poll_reset(cx) {
return Poll::Ready(Err(match reset {
Ok(reason) => format_err!("stream received RST_STREAM: {:?}", reason),
Err(err) => Error::from(err),
}));
}
Poll::Ready(Ok(()))
}
}
}