public AsyncLock()
{
_semaphore = new SemaphoreSlim(1);
_semaphoreRelease = new SafeSemaphoreRelease(this);
_lockTaken = new AsyncLocal <bool>(LockTakenValueChanged);
_lockTaken.Value = false;
}
public Task <IAsyncDisposable> TakeLockAsync()
{
if (_intDisposedStatus != 0)
{
return(Task.FromException <IAsyncDisposable>(new ObjectDisposedException(nameof(AsyncLock))));
}
DebuggableSemaphoreSlim objNextSemaphore = Utils.SemaphorePool.Get();
DebuggableSemaphoreSlim objCurrentSemaphore = _objCurrentSemaphore.Value ?? _objTopLevelSemaphore;
_objCurrentSemaphore.Value = objNextSemaphore;
SafeSemaphoreRelease objRelease = new SafeSemaphoreRelease(objCurrentSemaphore, objNextSemaphore, this);
return(TakeLockCoreAsync(objCurrentSemaphore, objRelease));
}
public Task <IAsyncDisposable> TakeLockAsync()
{
if (_isDisposed)
{
throw new ObjectDisposedException(nameof(AsyncLock));
}
_currentSemaphore.Value = _currentSemaphore.Value ?? _topLevelSemaphore;
SemaphoreSlim currentSem = _currentSemaphore.Value;
var nextSem = s_semaphorePool.Get();
_currentSemaphore.Value = nextSem;
var safeRelease = new SafeSemaphoreRelease(currentSem, nextSem, this);
return(TakeLockCoreAsync(currentSem, safeRelease));
}
private static async Task <IAsyncDisposable> TakeLockCoreAsync(DebuggableSemaphoreSlim objCurrentSemaphore, SafeSemaphoreRelease objRelease, CancellationToken token)
{
try
{
await objCurrentSemaphore.WaitAsync(token);
}
catch (OperationCanceledException)
{
//swallow this because it must be handled as a disposal in the original ExecutionContext
}
return(objRelease);
}
private static async Task <IAsyncDisposable> TakeLockCoreAsync(DebuggableSemaphoreSlim objCurrentSemaphore, SafeSemaphoreRelease objRelease)
{
await objCurrentSemaphore.WaitAsync();
return(objRelease);
}
public AsyncLock()
{
_semaphore = new SemaphoreSlim(1);
_semaphoreRelease = new SafeSemaphoreRelease(this);
}
private async Task <IAsyncDisposable> TakeLockCoreAsync(SemaphoreSlim currentSemaphore, SafeSemaphoreRelease safeSemaphoreRelease)
{
await currentSemaphore.WaitAsync();
return(safeSemaphoreRelease);
}