/// <summary>Initializes the <see cref="BufferBlock{T}"/> with the specified <see cref="DataflowBlockOptions"/>.</summary>
/// <param name="dataflowBlockOptions">The options with which to configure this <see cref="BufferBlock{T}"/>.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="dataflowBlockOptions"/> is null (Nothing in Visual Basic).</exception>
public BufferBlock(DataflowBlockOptions dataflowBlockOptions)
{
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException("dataflowBlockOptions");
}
Contract.EndContractBlock();
// Ensure we have options that can't be changed by the caller
dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// Initialize bounding state if necessary
Action <ISourceBlock <T>, int> onItemsRemoved = null;
if (dataflowBlockOptions.BoundedCapacity > 0)
{
onItemsRemoved = (owningSource, count) => ((BufferBlock <T>)owningSource).OnItemsRemoved(count);
_boundingState = new BoundingStateWithPostponedAndTask <T>(dataflowBlockOptions.BoundedCapacity);
}
// Initialize the source state
_source = new SourceCore <T>(this, dataflowBlockOptions,
owningSource => ((BufferBlock <T>)owningSource).Complete(),
onItemsRemoved);
// It is possible that the source half may fault on its own, e.g. due to a task scheduler exception.
// In those cases we need to fault the target half to drop its buffered messages and to release its
// reservations. This should not create an infinite loop, because all our implementations are designed
// to handle multiple completion requests and to carry over only one.
#if NET_4_0_ABOVE
_source.Completion.ContinueWith((completed, state) =>
{
var thisBlock = ((BufferBlock <T>)state) as IDataflowBlock;
Debug.Assert(completed.IsFaulted, "The source must be faulted in order to trigger a target completion.");
thisBlock.Fault(completed.Exception);
}, this, CancellationToken.None, Common.GetContinuationOptions() | TaskContinuationOptions.OnlyOnFaulted, TaskScheduler.Default);
#else
Action <Task> continuationAction = completed =>
{
var thisBlock = this as IDataflowBlock;
Debug.Assert(completed.IsFaulted, "The source must be faulted in order to trigger a target completion.");
thisBlock.Fault(completed.Exception);
};
_source.Completion.ContinueWith(continuationAction, CancellationToken.None, Common.GetContinuationOptions() | TaskContinuationOptions.OnlyOnFaulted, TaskScheduler.Default);
#endif
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, _source.Completion, owningSource => ((BufferBlock <T>)owningSource).Complete(), this);
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
#endif
}
/// <summary>Initializes the <see cref="WriteOnceBlock{T}"/> with the specified <see cref="DataflowBlockOptions"/>.</summary>
/// <param name="cloningFunction">
/// The function to use to clone the data when offered to other blocks.
/// This may be null to indicate that no cloning need be performed.
/// </param>
/// <param name="dataflowBlockOptions">The options with which to configure this <see cref="WriteOnceBlock{T}"/>.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="dataflowBlockOptions"/> is null (Nothing in Visual Basic).</exception>
public WriteOnceBlock(Func <T, T> cloningFunction, DataflowBlockOptions dataflowBlockOptions)
{
// Validate arguments
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException("dataflowBlockOptions");
}
Contract.EndContractBlock();
// Store the option
_cloningFunction = cloningFunction;
_dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// The target registry also serves as our ValueLock,
// and thus must always be initialized, even if the block is pre-canceled, as
// subsequent usage of the block may run through code paths that try to take this lock.
_targetRegistry = new TargetRegistry <T>(this);
// If a cancelable CancellationToken has been passed in,
// we need to initialize the completion task's TCS now.
if (dataflowBlockOptions.CancellationToken.CanBeCanceled)
{
_lazyCompletionTaskSource = new TaskCompletionSource <VoidResult>();
// If we've already had cancellation requested, do as little work as we have to
// in order to be done.
if (dataflowBlockOptions.CancellationToken.IsCancellationRequested)
{
_completionReserved = _decliningPermanently = true;
// Cancel the completion task's TCS
_lazyCompletionTaskSource.SetCanceled();
}
else
{
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, _lazyCompletionTaskSource.Task, state => ((WriteOnceBlock <T>)state).Complete(), this);
}
}
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
#endif
}