use std::fs::{self, OpenOptions};
use std::io;
use std::path::{Path, PathBuf};
use fd_lock::RwLock;
const CACHE_LOCK_FILE_NAME: &str = "scans.lock";
pub fn scans_lock_path(cache_root: &Path) -> PathBuf {
cache_root.join(CACHE_LOCK_FILE_NAME)
}
pub fn with_exclusive_cache_lock<T, E, F>(cache_root: &Path, operation: F) -> Result<T, E>
where
E: From<io::Error>,
F: FnOnce() -> Result<T, E>,
{
fs::create_dir_all(cache_root).map_err(E::from)?;
let lock_file = OpenOptions::new()
.read(true)
.write(true)
.create(true)
.truncate(false)
.open(scans_lock_path(cache_root))
.map_err(E::from)?;
let mut lock = RwLock::new(lock_file);
let _guard = lock.write().map_err(E::from)?;
operation()
}
#[cfg(test)]
mod tests {
use std::fs;
use tempfile::TempDir;
use super::*;
#[test]
fn test_with_exclusive_cache_lock_creates_sidecar_lock_file() {
let temp_dir = TempDir::new().expect("create temp dir");
let result: io::Result<()> = with_exclusive_cache_lock(temp_dir.path(), || Ok(()));
result.expect("lock should succeed");
assert!(fs::metadata(scans_lock_path(temp_dir.path())).is_ok());
}
}