async-lock

Reference-counted async lock.

The Lock type is similar to std::sync::Mutex, except locking is an async operation.

Note that Lock by itself acts like an Arc in the sense that cloning it returns just another reference to the same lock.

Furthermore, LockGuard is not tied to Lock by a lifetime, so you can keep guards for as long as you want. This is useful when you want to spawn a task and move a guard into its future.

The locking mechanism uses eventual fairness to ensure locking will be fair on average without sacrificing performance. This is done by forcing a fair lock whenever a lock operation is starved for longer than 0.5 milliseconds.

Examples

use async_lock::Lock;
use smol::Task;

let lock = Lock::new(0);
let mut tasks = vec![];

for _ in 0..10 {
    let lock = lock.clone();
    tasks.push(Task::spawn(async move { *lock.lock().await += 1 }));
}

for task in tasks {
    task.await;
}
assert_eq!(*lock.lock().await, 10);

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.