/// <summary>
/// Returns a task that completes when the write lock for the specified <paramref name="key"/> has been aquired.
/// The aquired Releaser must be disposed to release the write lock.
/// </summary>
/// <returns></returns>
public Task <Releaser> WriterLockAsync(TKey key)
{
//Get or create the lock for this key
AsyncReaderWriterWrapper wrapper = GetLockForKeyAndIncrement(key);
//Obtain the write lock
return(wrapper.Lock.WriterLockAsync().ContinueWith(t => new Releaser(key, this, t.Result)));
}
/// <summary>
/// Gets or creates the <see cref="AsyncReaderWriterWrapper"/> for the specified <paramref name="key"/> and increments the number
/// of references to the <see cref="AsyncReaderWriterWrapper"/>.
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
protected AsyncReaderWriterWrapper GetLockForKeyAndIncrement(TKey key)
{
lock (_syncObj)
{
AsyncReaderWriterWrapper wrapper;
if (!_locks.TryGetValue(key, out wrapper))
{
_locks[key] = wrapper = new AsyncReaderWriterWrapper();
}
else if (wrapper.ReferenceCount == 0)
{
_unusedKeys.Remove(key);
}
wrapper.ReferenceCount++;
return(wrapper);
}
}
