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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
use futures::{
future::{self, BoxFuture, FutureExt},
pin_mut, select, Future,
};
use sc_service::Error as ServiceError;
/// Abstraction over OS signals to handle the shutdown of the node smoothly.
///
/// On `unix` this represents `SigInt` and `SigTerm`.
pub struct Signals(BoxFuture<'static, ()>);
impl Signals {
/// Return the signals future.
pub fn future(self) -> BoxFuture<'static, ()> {
self.0
}
/// Capture the relevant signals to handle shutdown of the node smoothly.
///
/// Needs to be called in a Tokio context to have access to the tokio reactor.
#[cfg(target_family = "unix")]
pub fn capture() -> std::result::Result<Self, ServiceError> {
use tokio::signal::unix::{signal, SignalKind};
let mut stream_int = signal(SignalKind::interrupt()).map_err(ServiceError::Io)?;
let mut stream_term = signal(SignalKind::terminate()).map_err(ServiceError::Io)?;
Ok(Signals(
async move {
future::select(stream_int.recv().boxed(), stream_term.recv().boxed()).await;
}
.boxed(),
))
}
/// Capture the relevant signals to handle shutdown of the node smoothly.
///
/// Needs to be called in a Tokio context to have access to the tokio reactor.
#[cfg(not(unix))]
pub fn capture() -> Result<Self, ServiceError> {
use tokio::signal::ctrl_c;
Ok(Signals(
async move {
let _ = ctrl_c().await;
}
.boxed(),
))
}
/// A dummy signal that never returns.
pub fn dummy() -> Self {
Self(future::pending().boxed())
}
/// Run a future task until receive a signal.
pub async fn run_until_signal<F, E>(self, func: F) -> Result<(), E>
where
F: Future<Output = Result<(), E>> + future::FusedFuture,
E: std::error::Error + Send + Sync + 'static,
{
let signals = self.future().fuse();
pin_mut!(func, signals);
select! {
_ = signals => {},
res = func => res?,
}
Ok(())
}
/// Execute the future task and returns it's value if it completes before the signal.
pub async fn try_until_signal<F, T>(self, func: F) -> Result<T, ()>
where
F: Future<Output = T> + future::FusedFuture,
{
let signals = self.future().fuse();
pin_mut!(func, signals);
select! {
s = signals => Err(s),
res = func => Ok(res),
}
}
}