[](https://github.com/smessmer/lockpool/actions/workflows/ci.yml)
[](https://crates.io/crates/lockpool)
[](https://docs.rs/lockpool)
[](https://github.com/smessmer/lockpool/blob/master/LICENSE-MIT)
[](https://github.com/smessmer/lockpool/blob/master/LICENSE-APACHE)
[](https://codecov.io/gh/smessmer/lockpool)
# lockpool
This library offers a pool of locks where individual locks can be locked/unlocked by key.
It initially considers all keys as "unlocked", but they can be locked
and if a second thread tries to acquire a lock for the same key, they will have to wait.
```rust
use lockpool::LockPool;
let pool = LockPool::new();
let guard1 = pool.lock(4)?;
let guard2 = pool.lock(5)?;
// This next line would cause a deadlock or panic because `4` is already locked on this thread
// let guard3 = pool.lock(4)?;
// After dropping the corresponding guard, we can lock it again
std::mem::drop(guard1);
let guard3 = pool.lock(4)?;
```
You can use an arbitrary type to index locks by, as long as that type implements [PartialEq](https://docs.rs/tokenpool/latest/binary_layout/struct.PartialEq.html) + [Eq](https://docs.rs/tokenpool/latest/binary_layout/struct.Eq.html) + [Hash](https://docs.rs/tokenpool/latest/binary_layout/struct.Hash.html) + [Clone](https://docs.rs/tokenpool/latest/binary_layout/struct.Clone.html) + [Debug](https://docs.rs/tokenpool/latest/binary_layout/struct.Debug.html).
```rust
use lockpool::LockPool;
#[derive(PartialEq, Eq, Hash, Clone, Debug)]
struct CustomLockKey(u32);
let pool = LockPool::new();
let guard = pool.lock(CustomLockKey(4))?;
```
Under the hood, a [LockPool](https://docs.rs/tokenpool/latest/binary_layout/struct.LockPool.html) is a [HashMap](https://docs.rs/tokenpool/latest/binary_layout/struct.HashMap.html) of [Mutex](https://docs.rs/tokenpool/latest/binary_layout/struct.Mutex.html)es, with some logic making sure there aren't any race conditions when accessing the hash map.
License: MIT OR Apache-2.0