1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200

use bytes::IntoBuf;
use futures::{Async, Future, Poll, Stream};
use futures::future::{self, Either};
use futures::sync::{mpsc, oneshot};
use h2::client::{Builder, Handshake, SendRequest};
use tokio_io::{AsyncRead, AsyncWrite};

use headers::content_length_parse_all;
use body::Payload;
use ::common::{Exec, Never};
use headers;
use ::proto::Dispatched;
use super::{PipeToSendStream, SendBuf};
use ::{Body, Request, Response};

type ClientRx<B> = ::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) struct Client<T, B>
where
    B: Payload,
{
    executor: Exec,
    rx: ClientRx<B>,
    state: State<T, SendBuf<B::Data>>,
}

enum State<T, B> where B: IntoBuf {
    Handshaking(Handshake<T, B>),
    Ready(SendRequest<B>, ConnDropRef, ConnEof),
}

impl<T, B> Client<T, B>
where
    T: AsyncRead + AsyncWrite + Send + 'static,
    B: Payload,
{
    pub(crate) fn new(io: T, rx: ClientRx<B>, builder: &Builder, exec: Exec) -> Client<T, B> {
        let handshake = builder.handshake(io);

        Client {
            executor: exec,
            rx: rx,
            state: State::Handshaking(handshake),
        }
    }
}

impl<T, B> Future for Client<T, B>
where
    T: AsyncRead + AsyncWrite + Send + 'static,
    B: Payload + 'static,
{
    type Item = Dispatched;
    type Error = ::Error;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        loop {
            let next = match self.state {
                State::Handshaking(ref mut h) => {
                    let (request_tx, conn) = try_ready!(h.poll().map_err(::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 (tx, rx) = mpsc::channel(0);
                    let (cancel_tx, cancel_rx) = oneshot::channel();
                    let rx = rx.into_future()
                        .map(|(msg, _)| match msg {
                            Some(never) => match never {},
                            None => (),
                        })
                        .map_err(|_| -> Never { unreachable!("mpsc cannot error") });
                    let fut = conn
                        .inspect(move |_| {
                            drop(cancel_tx);
                            trace!("connection complete")
                        })
                        .map_err(|e| debug!("connection error: {}", e))
                        .select2(rx)
                        .then(|res| match res {
                            Ok(Either::A(((), _))) |
                            Err(Either::A(((), _))) => {
                                // conn has finished either way
                                Either::A(future::ok(()))
                            },
                            Ok(Either::B(((), conn))) => {
                                // mpsc has been dropped, hopefully polling
                                // the connection some more should start shutdown
                                // and then close
                                trace!("send_request dropped, starting conn shutdown");
                                Either::B(conn)
                            }
                            Err(Either::B((never, _))) => match never {},
                        });
                    self.executor.execute(fut)?;
                    State::Ready(request_tx, tx, cancel_rx)
                },
                State::Ready(ref mut tx, ref conn_dropper, ref mut cancel_rx) => {
                    match tx.poll_ready() {
                        Ok(Async::Ready(())) => (),
                        Ok(Async::NotReady) => return Ok(Async::NotReady),
                        Err(err) => {
                            return if err.reason() == Some(::h2::Reason::NO_ERROR) {
                                trace!("connection gracefully shutdown");
                                Ok(Async::Ready(Dispatched::Shutdown))
                            } else {
                                Err(::Error::new_h2(err))
                            };
                        }
                    }
                    match self.rx.poll() {
                        Ok(Async::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 tx.send_request(req, eos) {
                                Ok(ok) => ok,
                                Err(err) => {
                                    debug!("client send request error: {}", err);
                                    cb.send(Err((::Error::new_h2(err), None)));
                                    continue;
                                }
                            };
                            if !eos {
                                let mut pipe = PipeToSendStream::new(body, body_tx)
                                    .map_err(|e| debug!("client request body error: {}", e));

                                // eagerly see if the body pipe is ready and
                                // can thus skip allocating in the executor
                                match pipe.poll() {
                                    Ok(Async::Ready(())) | Err(()) => (),
                                    Ok(Async::NotReady) => {
                                        let conn_drop_ref = conn_dropper.clone();
                                        let pipe = pipe.then(move |x| {
                                                drop(conn_drop_ref);
                                                x
                                            });
                                        self.executor.execute(pipe)?;
                                    }
                                }
                            }

                            let fut = fut
                                .then(move |result| {
                                    match result {
                                        Ok(res) => {
                                            let content_length = content_length_parse_all(res.headers());
                                            let res = res.map(|stream|
                                                ::Body::h2(stream, content_length));
                                            Ok(res)
                                        },
                                        Err(err) => {
                                            debug!("client response error: {}", err);
                                            Err((::Error::new_h2(err), None))
                                        }
                                    }
                                });
                            self.executor.execute(cb.send_when(fut))?;
                            continue;
                        },

                        Ok(Async::NotReady) => {
                            match cancel_rx.poll() {
                                Ok(Async::Ready(never)) => match never {},
                                Ok(Async::NotReady) => return Ok(Async::NotReady),
                                Err(_conn_is_eof) => {
                                    trace!("connection task is closed, closing dispatch task");
                                    return Ok(Async::Ready(Dispatched::Shutdown));
                                }
                            }
                        },

                        Ok(Async::Ready(None)) => {
                            trace!("client::dispatch::Sender dropped");
                            return Ok(Async::Ready(Dispatched::Shutdown));
                        },
                        Err(never) => match never {},
                    }
                },
            };
            self.state = next;
        }
    }
}