alioth/src/sync/notifier/notifier_linux.rs - 02504ad

notifier_linux.rs56.67%

// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
use std::fs::File;
use std::io::{ErrorKind, Read, Result, Write};
use std::os::fd::{AsFd, AsRawFd, BorrowedFd, FromRawFd};
 
use libc::{EFD_CLOEXEC, EFD_NONBLOCK, eventfd};
use mio::event::Source;
use mio::unix::SourceFd;
use mio::{Interest, Registry, Token};
 
use crate::ffi;
 
#[derive(Debug)]
pub struct Notifier {
    fd: File,
}
 
impl Notifier {
    pub fn new() -> Result<Self> {16x
        let fd = ffi!(unsafe { eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK) })?;16x
        Ok(Notifier {16x
            fd: unsafe { File::from_raw_fd(fd) },16x
        })16x
    }16x
 
    pub fn notify(&self) -> Result<()> {36x
        let mut fd = &self.fd;36x
        let Err(e) = fd.write(&1u64.to_ne_bytes()) else {36x
            return Ok(());36x
        };
        if e.kind() != ErrorKind::WouldBlock {
            return Err(e);
        };
        let mut buf = [0u8; 8];
        let _ = fd.read(&mut buf)?;
        let _ = fd.write(&1u64.to_ne_bytes())?;
        Ok(())
    }36x
}
 
impl Source for Notifier {
    fn register(&mut self, registry: &Registry, token: Token, interests: Interest) -> Result<()> {16x
        registry.register(&mut SourceFd(&self.fd.as_raw_fd()), token, interests)16x
    }16x
 
    fn reregister(&mut self, registry: &Registry, token: Token, interests: Interest) -> Result<()> {
        registry.reregister(&mut SourceFd(&self.fd.as_raw_fd()), token, interests)
    }
 
    fn deregister(&mut self, registry: &Registry) -> std::io::Result<()> {4x
        registry.deregister(&mut SourceFd(&self.fd.as_raw_fd()))4x
    }4x
}
 
impl AsFd for Notifier {
    fn as_fd(&self) -> BorrowedFd<'_> {
        self.fd.as_fd()
    }
}
 