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#![cfg_attr(not(feature = "rt"), allow(dead_code))]
//! Process driver
use crate::park::Park;
use crate::process::unix::orphan::ReapOrphanQueue;
use crate::process::unix::GlobalOrphanQueue;
use crate::signal::unix::driver::Driver as SignalDriver;
use crate::signal::unix::{signal_with_handle, InternalStream, Signal, SignalKind};
use crate::sync::mpsc::error::TryRecvError;
use std::io;
use std::time::Duration;
/// Responsible for cleaning up orphaned child processes on Unix platforms.
#[derive(Debug)]
pub(crate) struct Driver {
park: SignalDriver,
inner: CoreDriver<Signal, GlobalOrphanQueue>,
}
#[derive(Debug)]
struct CoreDriver<S, Q> {
sigchild: S,
orphan_queue: Q,
}
// ===== impl CoreDriver =====
impl<S, Q> CoreDriver<S, Q>
where
S: InternalStream,
Q: ReapOrphanQueue,
{
fn got_signal(&mut self) -> bool {
match self.sigchild.try_recv() {
Ok(()) => true,
Err(TryRecvError::Empty) => false,
Err(TryRecvError::Closed) => panic!("signal was deregistered"),
}
}
fn process(&mut self) {
if self.got_signal() {
// Drain all notifications which may have been buffered
// so we can try to reap all orphans in one batch
while self.got_signal() {}
self.orphan_queue.reap_orphans();
}
}
}
// ===== impl Driver =====
impl Driver {
/// Creates a new signal `Driver` instance that delegates wakeups to `park`.
pub(crate) fn new(park: SignalDriver) -> io::Result<Self> {
let sigchild = signal_with_handle(SignalKind::child(), park.handle())?;
let inner = CoreDriver {
sigchild,
orphan_queue: GlobalOrphanQueue,
};
Ok(Self { park, inner })
}
}
// ===== impl Park for Driver =====
impl Park for Driver {
type Unpark = <SignalDriver as Park>::Unpark;
type Error = io::Error;
fn unpark(&self) -> Self::Unpark {
self.park.unpark()
}
fn park(&mut self) -> Result<(), Self::Error> {
self.park.park()?;
self.inner.process();
Ok(())
}
fn park_timeout(&mut self, duration: Duration) -> Result<(), Self::Error> {
self.park.park_timeout(duration)?;
self.inner.process();
Ok(())
}
fn shutdown(&mut self) {
self.park.shutdown()
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::process::unix::orphan::test::MockQueue;
use crate::sync::mpsc::error::TryRecvError;
use std::task::{Context, Poll};
struct MockStream {
total_try_recv: usize,
values: Vec<Option<()>>,
}
impl MockStream {
fn new(values: Vec<Option<()>>) -> Self {
Self {
total_try_recv: 0,
values,
}
}
}
impl InternalStream for MockStream {
fn poll_recv(&mut self, _cx: &mut Context<'_>) -> Poll<Option<()>> {
unimplemented!();
}
fn try_recv(&mut self) -> Result<(), TryRecvError> {
self.total_try_recv += 1;
match self.values.remove(0) {
Some(()) => Ok(()),
None => Err(TryRecvError::Empty),
}
}
}
#[test]
fn no_reap_if_no_signal() {
let mut driver = CoreDriver {
sigchild: MockStream::new(vec![None]),
orphan_queue: MockQueue::<()>::new(),
};
driver.process();
assert_eq!(1, driver.sigchild.total_try_recv);
assert_eq!(0, driver.orphan_queue.total_reaps.get());
}
#[test]
fn coalesce_signals_before_reaping() {
let mut driver = CoreDriver {
sigchild: MockStream::new(vec![Some(()), Some(()), None]),
orphan_queue: MockQueue::<()>::new(),
};
driver.process();
assert_eq!(3, driver.sigchild.total_try_recv);
assert_eq!(1, driver.orphan_queue.total_reaps.get());
}
}
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