use std::fs::{self, File};
use std::path::{Path, PathBuf};
use std::time::Duration;
use fs2::FileExt;
pub struct FileLock {
file: File,
#[allow(dead_code)]
path: PathBuf,
}
impl FileLock {
pub fn new(file: File, path: PathBuf) -> Self {
Self { file, path }
}
}
impl Drop for FileLock {
fn drop(&mut self) {
let _ = fs2::FileExt::unlock(&self.file);
}
}
pub fn acquire_file_lock(lock_path: &Path) -> anyhow::Result<FileLock> {
if let Some(parent) = lock_path.parent() {
fs::create_dir_all(parent)?;
}
let file = File::create(lock_path)?;
file.try_lock_exclusive()?;
Ok(FileLock::new(file, lock_path.to_path_buf()))
}
#[allow(dead_code)]
pub fn is_lock_stale(lock_path: &Path, threshold: Duration) -> bool {
if let Ok(metadata) = fs::metadata(lock_path)
&& let Ok(modified) = metadata.modified()
&& let Ok(elapsed) = modified.elapsed()
{
return elapsed > threshold;
}
false
}
#[allow(dead_code)]
pub fn remove_stale_lock(lock_path: &Path) -> bool {
if lock_path.exists() {
if let Err(e) = fs::remove_file(lock_path) {
tracing::warn!("Failed to remove stale lock {}: {e}", lock_path.display());
return false;
}
tracing::warn!("Removed stale lock: {}", lock_path.display());
return true;
}
false
}
#[cfg(test)]
mod tests {
use super::*;
use std::time::Duration;
use tempfile::TempDir;
#[test]
fn test_acquire_lock_succeeds_on_first_attempt() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join(".knot.lock");
let lock = acquire_file_lock(&lock_path);
assert!(lock.is_ok());
}
#[test]
fn test_acquire_lock_fails_when_already_held() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join(".knot.lock");
let _lock1 = acquire_file_lock(&lock_path).unwrap();
let lock2 = acquire_file_lock(&lock_path);
assert!(lock2.is_err());
}
#[test]
fn test_lock_released_on_drop() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join(".knot.lock");
{
let _lock = acquire_file_lock(&lock_path).unwrap();
}
let lock2 = acquire_file_lock(&lock_path);
assert!(lock2.is_ok());
}
#[test]
fn test_fresh_lock_not_stale() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join(".knot.lock");
File::create(&lock_path).unwrap();
assert!(!is_lock_stale(&lock_path, Duration::from_secs(3600)));
}
#[test]
fn test_remove_stale_lock_removes_file() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join(".knot.lock");
File::create(&lock_path).unwrap();
assert!(lock_path.exists());
assert!(remove_stale_lock(&lock_path));
assert!(!lock_path.exists());
}
#[test]
fn test_remove_stale_lock_nonexistent() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join("nonexistent.lock");
assert!(!remove_stale_lock(&lock_path));
}
#[test]
fn test_lock_creates_parent_directory() {
let dir = TempDir::new().unwrap();
let lock_path = dir.path().join("subdir").join(".knot.lock");
let lock = acquire_file_lock(&lock_path);
assert!(lock.is_ok());
assert!(lock_path.exists());
}
}