Files
hyper/src/proto/h2/client.rs
2019-08-21 11:58:02 -07:00

201 lines
7.2 KiB
Rust

use futures_channel::{mpsc, oneshot};
use futures_util::future::{self, FutureExt as _, Either};
use futures_util::stream::StreamExt as _;
use futures_util::try_future::TryFutureExt as _;
use h2::client::{Builder, SendRequest};
use tokio_io::{AsyncRead, AsyncWrite};
use crate::headers::content_length_parse_all;
use crate::body::Payload;
use crate::common::{Exec, Future, Never, Pin, Poll, task};
use crate::headers;
use crate::proto::Dispatched;
use super::{PipeToSendStream, SendBuf};
use crate::{Body, Request, Response};
type ClientRx<B> = crate::client::dispatch::Receiver<Request<B>, Response<Body>>;
///// An mpsc channel is used to help notify the `Connection` task when *all*
///// other handles to it have been dropped, so that it can shutdown.
type ConnDropRef = mpsc::Sender<Never>;
///// A oneshot channel watches the `Connection` task, and when it completes,
///// the "dispatch" task will be notified and can shutdown sooner.
type ConnEof = oneshot::Receiver<Never>;
pub(crate) async fn handshake<T, B>(
io: T,
req_rx: ClientRx<B>,
builder: &Builder,
exec: Exec,
) -> crate::Result<ClientTask<B>>
where
T: AsyncRead + AsyncWrite + Send + Unpin + 'static,
B: Payload,
B::Data: Unpin,
{
let (h2_tx, conn) = builder
.handshake::<_, SendBuf<B::Data>>(io)
.await
.map_err(crate::Error::new_h2)?;
// An mpsc channel is used entirely to detect when the
// 'Client' has been dropped. This is to get around a bug
// in h2 where dropping all SendRequests won't notify a
// parked Connection.
let (conn_drop_ref, rx) = mpsc::channel(1);
let (cancel_tx, conn_eof) = oneshot::channel();
let conn_drop_rx = rx.into_future()
.map(|(item, _rx)| {
match item {
Some(never) => match never {},
None => (),
}
});
let conn = conn.map_err(|e| debug!("connection error: {}", e));
let conn_task = async move {
match future::select(conn, conn_drop_rx).await {
Either::Left(_) => {
// ok or err, the `conn` has finished
}
Either::Right(((), conn)) => {
// mpsc has been dropped, hopefully polling
// the connection some more should start shutdown
// and then close
trace!("send_request dropped, starting conn shutdown");
drop(cancel_tx);
let _ = conn.await;
}
}
};
exec.execute(conn_task)?;
Ok(ClientTask {
conn_drop_ref,
conn_eof,
executor: exec,
h2_tx,
req_rx,
})
}
pub(crate) struct ClientTask<B>
where
B: Payload,
{
conn_drop_ref: ConnDropRef,
conn_eof: ConnEof,
executor: Exec,
h2_tx: SendRequest<SendBuf<B::Data>>,
req_rx: ClientRx<B>,
}
impl<B> Future for ClientTask<B>
where
B: Payload + Unpin + 'static,
B::Data: Unpin,
{
type Output = crate::Result<Dispatched>;
fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
loop {
match ready!(self.h2_tx.poll_ready(cx)) {
Ok(()) => (),
Err(err) => {
return if err.reason() == Some(::h2::Reason::NO_ERROR) {
trace!("connection gracefully shutdown");
Poll::Ready(Ok(Dispatched::Shutdown))
} else {
Poll::Ready(Err(crate::Error::new_h2(err)))
};
}
};
match Pin::new(&mut self.req_rx).poll_next(cx) {
Poll::Ready(Some((req, cb))) => {
// check that future hasn't been canceled already
if cb.is_canceled() {
trace!("request callback is canceled");
continue;
}
let (head, body) = req.into_parts();
let mut req = ::http::Request::from_parts(head, ());
super::strip_connection_headers(req.headers_mut(), true);
if let Some(len) = body.content_length() {
headers::set_content_length_if_missing(req.headers_mut(), len);
}
let eos = body.is_end_stream();
let (fut, body_tx) = match self.h2_tx.send_request(req, eos) {
Ok(ok) => ok,
Err(err) => {
debug!("client send request error: {}", err);
cb.send(Err((crate::Error::new_h2(err), None)));
continue;
}
};
if !eos {
let mut pipe = PipeToSendStream::new(body, body_tx)
.map(|res| {
if let Err(e) = res {
debug!("client request body error: {}", e);
}
});
// eagerly see if the body pipe is ready and
// can thus skip allocating in the executor
match Pin::new(&mut pipe).poll(cx) {
Poll::Ready(_) => (),
Poll::Pending => {
let conn_drop_ref = self.conn_drop_ref.clone();
let pipe = pipe.map(move |x| {
drop(conn_drop_ref);
x
});
self.executor.execute(pipe)?;
}
}
}
let fut = fut
.map(move |result| {
match result {
Ok(res) => {
let content_length = content_length_parse_all(res.headers());
let res = res.map(|stream|
crate::Body::h2(stream, content_length));
Ok(res)
},
Err(err) => {
debug!("client response error: {}", err);
Err((crate::Error::new_h2(err), None))
}
}
});
self.executor.execute(cb.send_when(fut))?;
continue;
},
Poll::Ready(None) => {
trace!("client::dispatch::Sender dropped");
return Poll::Ready(Ok(Dispatched::Shutdown));
}
Poll::Pending => {
match ready!(Pin::new(&mut self.conn_eof).poll(cx)) {
Ok(never) => match never {},
Err(_conn_is_eof) => {
trace!("connection task is closed, closing dispatch task");
return Poll::Ready(Ok(Dispatched::Shutdown));
}
}
},
}
}
}
}