Async Exclusive Lock

AsyncExclusiveLock provides asynchronous acquisition operation compatible with await operator. The only one caller can acquire the lock at a time. Behavior of this lock is similar to the monitor lock. Under contention, locks favor granting access to the longest-waiting task.

using DotNext.Threading;
using System.Threading;

var @lock = new AsyncExclusiveLock();

await @lock.AcquireAsync(CancellationToken.None);
try
{
    //synchronized access to the resource
}
finally
{
    @lock.Release();
}

//or with 'using' statement:
using(await @lock.AcquireLockAsync(CancellationToken.None))
{
    //synchronized access to the resource
}

This class supports methods to determine whether locks are held or contended. These methods are designed for monitoring system state, not for synchronization control.

Exclusive lock should be destroyed if no longer needed by calling Dispose method which is not thread-safe.

Graceful Shutdown

Dispose method is not thread-safe and may cause unpredictable behavior if called on the lock which was acquired previously. This is happening because the method doesn't wait for the lock to be released. Starting with version 2.6.0 this type of lock implements IAsyncDisposable interface and provides a way for graceful shutdown. DisposeAsync behaves in the following way:

• If lock is not acquired then completes synchronously
• If lock is acquired then suspends the caller and wait when it will be released, then dispose the lock

Synchronous acquisition

The class exposes TryAcquire(TimeSpan) blocking method that can be used by synchronous callers. The method allows to perform mixed synchronization for synchronous and asynchronous code at the same time.