Class AsyncParkingLot

Represents a set of wait queues shared by many lightweight asynchronous locks.

Inheritance

object

Disposable

AsyncParkingLot

Implements

IDisposable

Inherited Members

Disposable.CreateException()

Disposable.GetDisposedTask<T>()

Disposable.TrySetDisposedException<T>(TaskCompletionSource<T>)

Disposable.TrySetDisposedException(TaskCompletionSource)

Disposable.DisposeAsyncCore()

Disposable.DisposeAsync()

Disposable.TryBeginDispose()

Disposable.Dispose()

Disposable.Dispose(IEnumerable<IDisposable>)

Disposable.DisposeAsync(params IEnumerable<IAsyncDisposable>)

Disposable.Dispose<TDisposable>(params ReadOnlySpan<TDisposable>)

Disposable.IsDisposed

Disposable.IsDisposing

Disposable.IsDisposingOrDisposed

Disposable.DisposedTask

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Namespace: DotNext.Threading

Assembly: DotNext.Threading.dll

Syntax

public class AsyncParkingLot : Disposable, IDisposable

Remarks

Each lock is represented by a field of type AsyncParkingLot.State owned by the caller, so the lock itself doesn't require any allocation. The wait queue is allocated only for the contended locks. The lock is identified by its position and optional user data. The positions mapped to the same slot share the wait queue, but they don't block each other.

The ownership is handed off to the first waiter on release, so the waiters are resumed in FIFO order. The lock is not reentrant and doesn't track the owner.

Constructors

AsyncParkingLot(int, long?)

Initializes a new parking lot.

Declaration

public AsyncParkingLot(int capacity, long? poolSizePerSlot = null)

Parameters

Type	Name	Description
int	capacity	The number of slots. It is rounded up to the nearest power of two.
long?	poolSizePerSlot	The maximum number of wait nodes retained by the pool of each slot; or null to retain all of them.

Exceptions

Type	Condition
ArgumentOutOfRangeException	capacity is less than or equal to zero; or poolSizePerSlot is less than or equal to zero.

Properties

Capacity

Gets the number of slots.

Declaration

public int Capacity { get; }

Property Value

Type	Description
int

MeasurementTags

Sets a list of tags to be associated with each measurement.

Declaration

[CLSCompliant(false)]
public TagList MeasurementTags { init; }

Property Value

Type	Description
TagList

Methods

Dispose(bool)

Releases managed and unmanaged resources associated with this object.

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	true if called from Dispose(); false if called from finalizer ~Disposable().

Overrides

Disposable.Dispose(bool)

ParkAsync(int, ref State, object?, CancellationToken)

Acquires the lock asynchronously.

Declaration

public ValueTask ParkAsync(int position, ref AsyncParkingLot.State state, object? userData = null, CancellationToken token = default)

Parameters

Type	Name	Description
int	position	The position of the lock.
AsyncParkingLot.State	state	The state of the lock.
object	userData	The object that distinguishes the locks with the same position. It is compared by reference, so Unpark(int, ref State, object?) must be called with the same object.
CancellationToken	token	The token that can be used to cancel the operation.

Returns

Type	Description
ValueTask	The task representing lock acquisition.

Remarks

The returned task must be awaited. Otherwise, the wait node of the canceled caller is never removed from the wait queue.

Exceptions

Type	Condition
ArgumentOutOfRangeException	position is negative.
OperationCanceledException	The operation has been canceled.
ObjectDisposedException	This object is disposed.

ParkAsync(int, ref State, object?, TimeSpan, CancellationToken)

Acquires the lock asynchronously, with a time-out.

Declaration

public ValueTask<bool> ParkAsync(int position, ref AsyncParkingLot.State state, object? userData, TimeSpan timeout, CancellationToken token = default)

Parameters

Type	Name	Description
int	position	The position of the lock.
AsyncParkingLot.State	state	The state of the lock.
object	userData	The object that distinguishes the locks with the same position. It is compared by reference, so Unpark(int, ref State, object?) must be called with the same object.
TimeSpan	timeout	The interval to wait for the lock.
CancellationToken	token	The token that can be used to cancel the operation.

Returns

Type	Description
ValueTask<bool>	true if the lock is acquired; false if timed out.

Remarks

The returned task must be awaited. Otherwise, the wait node of the timed out or canceled caller is never removed from the wait queue.

Exceptions

Type	Condition
ArgumentOutOfRangeException	position is negative; or timeout is negative.
OperationCanceledException	The operation has been canceled.
ObjectDisposedException	This object is disposed.

TryPark(ref State)

Attempts to acquire the lock synchronously, without waiting.

Declaration

public static bool TryPark(ref AsyncParkingLot.State state)

Parameters

Type	Name	Description
AsyncParkingLot.State	state	The state of the lock.

Returns

Type	Description
bool	true if the lock is acquired; false if the lock is already acquired.

Unpark(int, ref State, object?)

Releases the lock.

Declaration

public void Unpark(int position, ref AsyncParkingLot.State state, object? userData = null)

Parameters

Type	Name	Description
int	position	The position of the lock.
AsyncParkingLot.State	state	The state of the lock.
object	userData	The object passed to ParkAsync(int, ref State, object?, CancellationToken).

Remarks

If the lock has waiters, the ownership is handed off to the first of them. The method must be called by the lock owner only, it's not checked.

Exceptions

Type	Condition
ArgumentOutOfRangeException	position is negative.
InvalidOperationException	The lock is not acquired.

Implements

IDisposable

Extension Methods

BasicExtensions.As<T>(T)

BasicExtensions.IsBetween<T, TLowerBound, TUpperBound>(T, TLowerBound, TUpperBound)

BasicExtensions.IsOneOf<T>(T, params ReadOnlySpan<T>)