use std::error::Error as StdError;
use tokio_io::{AsyncRead, AsyncWrite};
use pin_project::{pin_project, project};
use crate::body::{Body, Payload};
use crate::common::drain::{self, Draining, Signal, Watch, Watching};
use crate::common::exec::{H2Exec, NewSvcExec};
use crate::common::{Future, Pin, Poll, Unpin, task};
use crate::service::{MakeServiceRef, Service};
use super::Accept;
use super::conn::{SpawnAll, UpgradeableConnection, Watcher};
#[allow(missing_debug_implementations)]
#[pin_project]
pub struct Graceful<I, S, F, E> {
#[pin]
state: State<I, S, F, E>,
}
#[pin_project]
pub(super) enum State<I, S, F, E> {
Running {
drain: Option<(Signal, Watch)>,
#[pin]
spawn_all: SpawnAll<I, S, E>,
#[pin]
signal: F,
},
Draining(Draining),
}
impl<I, S, F, E> Graceful<I, S, F, E> {
pub(super) fn new(spawn_all: SpawnAll<I, S, E>, signal: F) -> Self {
let drain = Some(drain::channel());
Graceful {
state: State::Running {
drain,
spawn_all,
signal,
},
}
}
}
impl<I, IO, IE, S, B, F, E> Future for Graceful<I, S, F, E>
where
I: Accept<Conn=IO, Error=IE>,
IE: Into<Box<dyn StdError + Send + Sync>>,
IO: AsyncRead + AsyncWrite + Unpin + Send + 'static,
S: MakeServiceRef<IO, Body, ResBody=B>,
S::Service: 'static,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
B: Payload,
B::Data: Unpin,
F: Future<Output=()>,
E: H2Exec<<S::Service as Service<Body>>::Future, B>,
E: NewSvcExec<IO, S::Future, S::Service, E, GracefulWatcher>,
{
type Output = crate::Result<()>;
#[project]
fn poll(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
let mut me = self.project();
loop {
let next = {
#[project]
match me.state.as_mut().project() {
State::Running {
drain,
spawn_all,
signal,
} => match signal.poll(cx) {
Poll::Ready(()) => {
debug!("signal received, starting graceful shutdown");
let sig = drain
.take()
.expect("drain channel")
.0;
State::Draining(sig.drain())
},
Poll::Pending => {
let watch = drain
.as_ref()
.expect("drain channel")
.1
.clone();
return spawn_all.poll_watch(cx, &GracefulWatcher(watch));
},
},
State::Draining(ref mut draining) => {
return Pin::new(draining).poll(cx).map(Ok);
}
}
};
me.state.set(next);
}
}
}
#[allow(missing_debug_implementations)]
#[derive(Clone)]
pub struct GracefulWatcher(Watch);
impl<I, S, E> Watcher<I, S, E> for GracefulWatcher
where
I: AsyncRead + AsyncWrite + Unpin + Send + 'static,
S: Service<Body> + 'static,
<S::ResBody as Payload>::Data: Unpin,
E: H2Exec<S::Future, S::ResBody>,
{
type Future = Watching<UpgradeableConnection<I, S, E>, fn(Pin<&mut UpgradeableConnection<I, S, E>>)>;
fn watch(&self, conn: UpgradeableConnection<I, S, E>) -> Self::Future {
self
.0
.clone()
.watch(conn, on_drain)
}
}
fn on_drain<I, S, E>(conn: Pin<&mut UpgradeableConnection<I, S, E>>)
where
S: Service<Body>,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
I: AsyncRead + AsyncWrite + Unpin,
S::ResBody: Payload + 'static,
<S::ResBody as Payload>::Data: Unpin,
E: H2Exec<S::Future, S::ResBody>,
{
conn.graceful_shutdown()
}