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use std::{os::unix::prelude::RawFd, slice};
use nix::{errno::Errno, fcntl::OFlag, poll, unistd};
use common::error::*;
use super::util::unix;
#[derive(Debug)]
pub struct Jobserver {
tokens: usize,
r: RawFd,
w: RawFd,
}
impl Jobserver {
pub fn new(tokens: usize) -> Result<Jobserver> {
let (r, w) = unistd::pipe2(OFlag::O_CLOEXEC | OFlag::O_NONBLOCK).context("pipe()")?;
for _ in 0..tokens {
if let Err(_) = unistd::write(w, b"+") {
break;
}
}
unix::set_blocking(w, true)?;
Ok(Jobserver { tokens, r, w })
}
pub fn wait(&mut self) -> u8 {
loop {
poll::poll(
&mut [poll::PollFd::new(self.r, poll::PollFlags::POLLIN)],
-1,
)
.expect("poll()");
let mut token = 0;
match unistd::read(self.r, slice::from_mut(&mut token)) {
Ok(n) => {
assert!(n == 1);
return token;
}
Err(Errno::EAGAIN) => {
// Token was sniped by another task
continue;
}
error @ Err(_) => {
error.expect("read()");
}
}
}
}
pub fn post(&mut self, token: u8) {
let n = unistd::write(self.w, slice::from_ref(&token)).expect("write()");
assert!(n == 1);
}
pub fn set_cloexec(&mut self, cloexec: bool) -> Result<()> {
unix::set_cloexec(self.r, cloexec)?;
unix::set_cloexec(self.w, cloexec)?;
Ok(())
}
pub fn to_makeflags(&self) -> String {
format!(" -j{} --jobserver-auth={},{}", self.tokens, self.r, self.w)
}
}
impl Drop for Jobserver {
fn drop(&mut self) {
// FIXME Logging
let _ = unistd::close(self.r);
let _ = unistd::close(self.w);
}
}
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