// Copyright 2020 The Jujutsu Authors//// 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.#![expect(missing_docs)]mod backoff;#[cfg(unix)]mod unix;#[cfg(windows)]mod windows;use std::io;use std::path::PathBuf;use thiserror::Error;#[cfg(unix)]pub use self::unix::FileLock;#[cfg(windows)]pub use self::windows::FileLock;#[derive(Debug, Error)]#[error("{message}: {path}")]pub struct FileLockError { pub message: &'static str, pub path: PathBuf, #[source] pub err: io::Error,}#[cfg(test)]#[cfg_attr(coverage_nightly, coverage(off))]mod tests { use std::cmp::max; use std::fs; use std::thread; use std::time::Duration; use super::*; use crate::tests::new_temp_dir; #[test] fn lock_basic() { let temp_dir = new_temp_dir(); let lock_path = temp_dir.path().join("test.lock"); assert!(!lock_path.exists()); { let _lock = FileLock::lock(lock_path.clone()).unwrap(); assert!(lock_path.exists()); } assert!(!lock_path.exists()); } #[test] fn lock_concurrent() { let temp_dir = new_temp_dir(); let data_path = temp_dir.path().join("test"); let lock_path = temp_dir.path().join("test.lock"); fs::write(&data_path, 0_u32.to_le_bytes()).unwrap(); let num_threads = max(num_cpus::get(), 4); thread::scope(|s| { for _ in 0..num_threads { s.spawn(|| { let _lock = FileLock::lock(lock_path.clone()).unwrap(); let data = fs::read(&data_path).unwrap(); let value = u32::from_le_bytes(data.try_into().unwrap()); thread::sleep(Duration::from_millis(1)); fs::write(&data_path, (value + 1).to_le_bytes()).unwrap(); }); } }); let data = fs::read(&data_path).unwrap(); let value = u32::from_le_bytes(data.try_into().unwrap()); assert_eq!(value, num_threads as u32); } #[test] fn try_lock_succeeds_when_unlocked() { let temp_dir = new_temp_dir(); let lock_path = temp_dir.path().join("test.lock"); assert!(!lock_path.exists()); { let lock = FileLock::try_lock(lock_path.clone()).unwrap(); assert!(lock.is_some()); assert!(lock_path.exists()); } assert!(!lock_path.exists()); } #[test] fn try_lock_gives_up_when_locked() { let temp_dir = new_temp_dir(); let lock_path = temp_dir.path().join("test.lock"); let _held = FileLock::lock(lock_path.clone()).unwrap(); // The lock is already held, so a non-blocking attempt returns `None` // instead of blocking. The two lock handles are independent even within // a single process, so the second attempt is denied. assert!(FileLock::try_lock(lock_path).unwrap().is_none()); }}
// Copyright 2020 The Jujutsu Authors
//
// 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.
#![expect(missing_docs)]
mod backoff;
#[cfg(unix)]
mod unix;
#[cfg(windows)]
mod windows;
use std::io;
use std::path::PathBuf;
use thiserror::Error;
#[cfg(unix)]
pub use self::unix::FileLock;
#[cfg(windows)]
pub use self::windows::FileLock;
#[derive(Debug, Error)]
#[error("{message}: {path}")]
pub struct FileLockError {
pub message: &'static str,
pub path: PathBuf,
#[source]
pub err: io::Error,
}
#[cfg(test)]
#[cfg_attr(coverage_nightly, coverage(off))]
mod tests {
use std::cmp::max;
use std::fs;
use std::thread;
use std::time::Duration;
use super::*;
use crate::tests::new_temp_dir;
#[test]
fn lock_basic() {
let temp_dir = new_temp_dir();
let lock_path = temp_dir.path().join("test.lock");
assert!(!lock_path.exists());
{
let _lock = FileLock::lock(lock_path.clone()).unwrap();
assert!(lock_path.exists());
}
assert!(!lock_path.exists());
}
#[test]
fn lock_concurrent() {
let temp_dir = new_temp_dir();
let data_path = temp_dir.path().join("test");
let lock_path = temp_dir.path().join("test.lock");
fs::write(&data_path, 0_u32.to_le_bytes()).unwrap();
let num_threads = max(num_cpus::get(), 4);
thread::scope(|s| {
for _ in 0..num_threads {
s.spawn(|| {
let _lock = FileLock::lock(lock_path.clone()).unwrap();
let data = fs::read(&data_path).unwrap();
let value = u32::from_le_bytes(data.try_into().unwrap());
thread::sleep(Duration::from_millis(1));
fs::write(&data_path, (value + 1).to_le_bytes()).unwrap();
});
}
});
let data = fs::read(&data_path).unwrap();
let value = u32::from_le_bytes(data.try_into().unwrap());
assert_eq!(value, num_threads as u32);
}
#[test]
fn try_lock_succeeds_when_unlocked() {
let temp_dir = new_temp_dir();
let lock_path = temp_dir.path().join("test.lock");
assert!(!lock_path.exists());
{
let lock = FileLock::try_lock(lock_path.clone()).unwrap();
assert!(lock.is_some());
assert!(lock_path.exists());
}
assert!(!lock_path.exists());
}
#[test]
fn try_lock_gives_up_when_locked() {
let temp_dir = new_temp_dir();
let lock_path = temp_dir.path().join("test.lock");
let _held = FileLock::lock(lock_path.clone()).unwrap();
// The lock is already held, so a non-blocking attempt returns `None`
// instead of blocking. The two lock handles are independent even within
// a single process, so the second attempt is denied.
assert!(FileLock::try_lock(lock_path).unwrap().is_none());
}
}