/// <summary>Called when postponed messages may need to be consumed.</summary>
/// <param name="isReplacementReplica">Whether this call is the continuation of a previous message loop.</param>
internal void ConsumeAsyncIfNecessary(bool isReplacementReplica = false)
{
Common.ContractAssertMonitorStatus(IncomingLock, held: true);
Debug.Assert(_boundingState != null, "Must be in bounded mode.");
if (!_targetDecliningPermanently &&
_boundingState.TaskForInputProcessing == null &&
_boundingState.PostponedMessages.Count > 0 &&
_boundingState.CountIsLessThanBound)
{
// Create task and store into _taskForInputProcessing prior to scheduling the task
// so that _taskForInputProcessing will be visibly set in the task loop.
_boundingState.TaskForInputProcessing =
new Task(state => ((BufferBlock <T>)state !).ConsumeMessagesLoopCore(), this,
Common.GetCreationOptionsForTask(isReplacementReplica));
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.TaskLaunchedForMessageHandling(
this, _boundingState.TaskForInputProcessing, DataflowEtwProvider.TaskLaunchedReason.ProcessingInputMessages,
_boundingState.PostponedMessages.Count);
}
// Start the task handling scheduling exceptions
Exception?exception = Common.StartTaskSafe(_boundingState.TaskForInputProcessing, _source.DataflowBlockOptions.TaskScheduler);
if (exception != null)
{
// Get out from under currently held locks. CompleteCore re-acquires the locks it needs.
Task.Factory.StartNew(exc => CompleteCore(exception: (Exception)exc !, storeExceptionEvenIfAlreadyCompleting: true, revertProcessingState: true),
exception, CancellationToken.None, Common.GetCreationOptionsForTask(), TaskScheduler.Default);
}
}
}
/// <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
}
/// <summary>Completes the block.</summary>
/// <remarks>
/// This is called only once.
/// </remarks>
private void CompleteBlock(IList <Exception> exceptions)
{
// Do not invoke the CompletionTaskSource property if there is a chance that _lazyCompletionTaskSource
// has not been initialized yet and we may have to complete normally, because that would defeat the
// sole purpose of the TCS being lazily initialized.
Contract.Requires(_lazyCompletionTaskSource == null || !_lazyCompletionTaskSource.Task.IsCompleted, "The task completion source must not be completed. This must be the only thread that ever completes the block.");
// Save the linked list of targets so that it could be traversed later to propagate completion
TargetRegistry <T> .LinkedTargetInfo linkedTargets = _targetRegistry.ClearEntryPoints();
// Complete the block's completion task
if (exceptions != null && exceptions.Count > 0)
{
CompletionTaskSource.TrySetException(exceptions);
}
else if (_dataflowBlockOptions.CancellationToken.IsCancellationRequested)
{
CompletionTaskSource.TrySetCanceled();
}
else
{
// Safely try to initialize the completion task's TCS with a cached completed TCS.
// If our attempt succeeds (CompareExchange returns null), we have nothing more to do.
// If the completion task's TCS was already initialized (CompareExchange returns non-null),
// we have to complete that TCS instance.
if (Interlocked.CompareExchange(ref _lazyCompletionTaskSource, Common.CompletedVoidResultTaskCompletionSource, null) != null)
{
_lazyCompletionTaskSource.TrySetResult(default(VoidResult));
}
}
// Now that the completion task is completed, we may propagate completion to the linked targets
_targetRegistry.PropagateCompletion(linkedTargets);
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCompleted(this);
}
#endif
}
private void CompleteBlockAsync(IList <Exception> exceptions)
{
Contract.Requires(_decliningPermanently, "We may get here only after we have started to decline permanently.");
Contract.Requires(_completionReserved, "We may get here only after we have reserved completion.");
Common.ContractAssertMonitorStatus(ValueLock, held: false);
// If there is no exceptions list, we offer the message around, and then complete.
// If there is an exception list, we complete without offering the message.
if (exceptions == null)
{
// Offer the message to any linked targets and complete the block asynchronously to avoid blocking the caller
var taskForOutputProcessing = new Task(state => ((WriteOnceBlock <T>)state).OfferToTargetsAndCompleteBlock(), this,
Common.GetCreationOptionsForTask());
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.TaskLaunchedForMessageHandling(
this, taskForOutputProcessing, DataflowEtwProvider.TaskLaunchedReason.OfferingOutputMessages, _header.IsValid ? 1 : 0);
}
#endif
// Start the task handling scheduling exceptions
Exception exception = Common.StartTaskSafe(taskForOutputProcessing, _dataflowBlockOptions.TaskScheduler);
if (exception != null)
{
CompleteCore(exception, storeExceptionEvenIfAlreadyCompleting: true);
}
}
else
{
// Complete the block asynchronously to avoid blocking the caller
Task.Factory.StartNew(state =>
{
Tuple <WriteOnceBlock <T>, IList <Exception> > blockAndList = (Tuple <WriteOnceBlock <T>, IList <Exception> >)state;
blockAndList.Item1.CompleteBlock(blockAndList.Item2);
},
Tuple.Create(this, exceptions), CancellationToken.None, Common.GetCreationOptionsForTask(), TaskScheduler.Default);
}
}
/// <summary>Initializes the <see cref="ActionBlock{T}"/> with the specified delegate and options.</summary>
/// <param name="action">The action to invoke with each data element received.</param>
/// <param name="dataflowBlockOptions">The options with which to configure this <see cref="ActionBlock{T}"/>.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="action"/> is null (Nothing in Visual Basic).</exception>
/// <exception cref="System.ArgumentNullException">The <paramref name="dataflowBlockOptions"/> is null (Nothing in Visual Basic).</exception>
private ActionBlock(Delegate action, ExecutionDataflowBlockOptions dataflowBlockOptions)
{
// Validate arguments
if (action == null)
{
throw new ArgumentNullException("action");
}
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException("dataflowBlockOptions");
}
Contract.Ensures((_spscTarget != null) ^ (_defaultTarget != null), "One and only one of the two targets must be non-null after construction");
Contract.EndContractBlock();
// Ensure we have options that can't be changed by the caller
dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// Based on the mode, initialize the target. If the user specifies SingleProducerConstrained,
// we'll try to employ an optimized mode under a limited set of circumstances.
var syncAction = action as Action <TInput>;
if (syncAction != null &&
dataflowBlockOptions.SingleProducerConstrained &&
dataflowBlockOptions.MaxDegreeOfParallelism == 1 &&
!dataflowBlockOptions.CancellationToken.CanBeCanceled &&
dataflowBlockOptions.BoundedCapacity == DataflowBlockOptions.Unbounded)
{
// Initialize the SPSC fast target to handle the bulk of the processing.
// The SpscTargetCore is only supported when BoundedCapacity, CancellationToken,
// and MaxDOP are all their default values. It's also only supported for sync
// delegates and not for async delegates.
_spscTarget = new SpscTargetCore <TInput>(this, syncAction, dataflowBlockOptions);
}
else
{
// Initialize the TargetCore which handles the bulk of the processing.
// The default target core can handle all options and delegate flavors.
if (syncAction != null) // sync
{
_defaultTarget = new TargetCore <TInput>(this,
messageWithId => ProcessMessage(syncAction, messageWithId),
null, dataflowBlockOptions, TargetCoreOptions.RepresentsBlockCompletion);
}
else // async
{
var asyncAction = action as Func <TInput, Task>;
Debug.Assert(asyncAction != null, "action is of incorrect delegate type");
_defaultTarget = new TargetCore <TInput>(this,
messageWithId => ProcessMessageWithTask(asyncAction, messageWithId),
null, dataflowBlockOptions, TargetCoreOptions.RepresentsBlockCompletion | TargetCoreOptions.UsesAsyncCompletion);
}
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, Completion, state => ((TargetCore <TInput>)state).Complete(exception: null, dropPendingMessages: true), _defaultTarget);
}
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
#endif
}
/// <summary>Initializes this <see cref="BatchedJoinBlock{T1,T2}"/> with the specified configuration.</summary>
/// <param name="batchSize">The number of items to group into a batch.</param>
/// <param name="dataflowBlockOptions">The options with which to configure this <see cref="BatchedJoinBlock{T1,T2}"/>.</param>
/// <exception cref="System.ArgumentOutOfRangeException">The <paramref name="batchSize"/> must be positive.</exception>
/// <exception cref="System.ArgumentNullException">The <paramref name="dataflowBlockOptions"/> is null (Nothing in Visual Basic).</exception>
public BatchedJoinBlock(int batchSize, GroupingDataflowBlockOptions dataflowBlockOptions)
{
// Validate arguments
if (batchSize < 1)
{
throw new ArgumentOutOfRangeException(nameof(batchSize), SR.ArgumentOutOfRange_GenericPositive);
}
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException(nameof(dataflowBlockOptions));
}
if (!dataflowBlockOptions.Greedy)
{
throw new ArgumentException(SR.Argument_NonGreedyNotSupported, nameof(dataflowBlockOptions));
}
if (dataflowBlockOptions.BoundedCapacity != DataflowBlockOptions.Unbounded)
{
throw new ArgumentException(SR.Argument_BoundedCapacityNotSupported, nameof(dataflowBlockOptions));
}
// Store arguments
_batchSize = batchSize;
dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// Configure the source
_source = new SourceCore <Tuple <IList <T1>, IList <T2> > >(
this, dataflowBlockOptions, owningSource => ((BatchedJoinBlock <T1, T2>)owningSource).CompleteEachTarget());
// The action to run when a batch should be created. This is typically called
// when we have a full batch, but it will also be called when we're done receiving
// messages, and thus when there may be a few stragglers we need to make a batch out of.
Action createBatchAction = () =>
{
if (_target1.Count > 0 || _target2.Count > 0)
{
_source.AddMessage(Tuple.Create(_target1.GetAndEmptyMessages(), _target2.GetAndEmptyMessages()));
}
};
// Configure the targets
_sharedResources = new BatchedJoinBlockTargetSharedResources(
batchSize, dataflowBlockOptions,
createBatchAction,
() =>
{
createBatchAction();
_source.Complete();
},
_source.AddException,
Complete);
_target1 = new BatchedJoinBlockTarget <T1>(_sharedResources);
_target2 = new BatchedJoinBlockTarget <T2>(_sharedResources);
// 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.
_source.Completion.ContinueWith((completed, state) =>
{
var thisBlock = ((BatchedJoinBlock <T1, T2>)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);
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, _source.Completion, state => ((BatchedJoinBlock <T1, T2>)state !).CompleteEachTarget(), this);
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
#endif
}
/// <summary>Initializes the <see cref="TransformManyBlock{TInput,TOutput}"/> with the specified function and <see cref="ExecutionDataflowBlockOptions"/>.</summary>
/// <param name="transformSync">The synchronous function to invoke with each data element received.</param>
/// <param name="transformAsync">The asynchronous function to invoke with each data element received.</param>
/// <param name="dataflowBlockOptions">The options with which to configure this <see cref="TransformManyBlock{TInput,TOutput}"/>.</param>
/// <exception cref="System.ArgumentNullException">The <paramref name="transformSync"/> and <paramref name="transformAsync"/> are both null (Nothing in Visual Basic).</exception>
/// <exception cref="System.ArgumentNullException">The <paramref name="dataflowBlockOptions"/> is null (Nothing in Visual Basic).</exception>
private TransformManyBlock(Func <TInput, IEnumerable <TOutput> > transformSync, Func <TInput, Task <IEnumerable <TOutput> > > transformAsync, ExecutionDataflowBlockOptions dataflowBlockOptions)
{
// Validate arguments. It's ok for the filterFunction to be null, but not the other parameters.
if (transformSync == null && transformAsync == null)
{
throw new ArgumentNullException("transform");
}
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException(nameof(dataflowBlockOptions));
}
Contract.Requires(transformSync == null ^ transformAsync == null, "Exactly one of transformSync and transformAsync must be null.");
Contract.EndContractBlock();
// Ensure we have options that can't be changed by the caller
dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// Initialize onItemsRemoved delegate if necessary
Action <ISourceBlock <TOutput>, int> onItemsRemoved = null;
if (dataflowBlockOptions.BoundedCapacity > 0)
{
onItemsRemoved = (owningSource, count) => ((TransformManyBlock <TInput, TOutput>)owningSource)._target.ChangeBoundingCount(-count);
}
// Initialize source component
_source = new SourceCore <TOutput>(this, dataflowBlockOptions,
owningSource => ((TransformManyBlock <TInput, TOutput>)owningSource)._target.Complete(exception: null, dropPendingMessages: true),
onItemsRemoved);
// If parallelism is employed, we will need to support reordering messages that complete out-of-order.
// However, a developer can override this with EnsureOrdered == false.
if (dataflowBlockOptions.SupportsParallelExecution && dataflowBlockOptions.EnsureOrdered)
{
_reorderingBuffer = new ReorderingBuffer <IEnumerable <TOutput> >(
this, (source, messages) => ((TransformManyBlock <TInput, TOutput>)source)._source.AddMessages(messages));
}
// Create the underlying target and source
if (transformSync != null) // sync
{
// If an enumerable function was provided, we can use synchronous completion, meaning
// that the target will consider a message fully processed as soon as the
// delegate returns.
_target = new TargetCore <TInput>(this,
messageWithId => ProcessMessage(transformSync, messageWithId),
_reorderingBuffer, dataflowBlockOptions, TargetCoreOptions.None);
}
else // async
{
Debug.Assert(transformAsync != null, "Incorrect delegate type.");
// If a task-based function was provided, we need to use asynchronous completion, meaning
// that the target won't consider a message completed until the task
// returned from that delegate has completed.
_target = new TargetCore <TInput>(this,
messageWithId => ProcessMessageWithTask(transformAsync, messageWithId),
_reorderingBuffer, dataflowBlockOptions, TargetCoreOptions.UsesAsyncCompletion);
}
// Link up the target half with the source half. In doing so,
// ensure exceptions are propagated, and let the source know no more messages will arrive.
// As the target has completed, and as the target synchronously pushes work
// through the reordering buffer when async processing completes,
// we know for certain that no more messages will need to be sent to the source.
_target.Completion.ContinueWith((completed, state) =>
{
var sourceCore = (SourceCore <TOutput>)state;
if (completed.IsFaulted)
{
sourceCore.AddAndUnwrapAggregateException(completed.Exception);
}
sourceCore.Complete();
}, _source, CancellationToken.None, Common.GetContinuationOptions(), TaskScheduler.Default);
// 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.
_source.Completion.ContinueWith((completed, state) =>
{
var thisBlock = ((TransformManyBlock <TInput, TOutput>)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);
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, Completion, state => ((TargetCore <TInput>)state).Complete(exception: null, dropPendingMessages: true), _target);
#if FEATURE_TRACING
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
#endif
}
private void Initialize(
Action <KeyValuePair <TInput, long> > processMessageAction,
ExecutionDataflowBlockOptions dataflowBlockOptions,
[NotNull] ref SourceCore <TOutput>?source,
[NotNull] ref TargetCore <TInput>?target,
ref ReorderingBuffer <IEnumerable <TOutput> >?reorderingBuffer,
TargetCoreOptions targetCoreOptions)
{
if (dataflowBlockOptions == null)
{
throw new ArgumentNullException(nameof(dataflowBlockOptions));
}
// Ensure we have options that can't be changed by the caller
dataflowBlockOptions = dataflowBlockOptions.DefaultOrClone();
// Initialize onItemsRemoved delegate if necessary
Action <ISourceBlock <TOutput>, int>?onItemsRemoved = null;
if (dataflowBlockOptions.BoundedCapacity > 0)
{
onItemsRemoved = (owningSource, count) => ((TransformManyBlock <TInput, TOutput>)owningSource)._target.ChangeBoundingCount(-count);
}
// Initialize source component
source = new SourceCore <TOutput>(this, dataflowBlockOptions,
owningSource => ((TransformManyBlock <TInput, TOutput>)owningSource)._target.Complete(exception: null, dropPendingMessages: true),
onItemsRemoved);
// If parallelism is employed, we will need to support reordering messages that complete out-of-order.
// However, a developer can override this with EnsureOrdered == false.
if (dataflowBlockOptions.SupportsParallelExecution && dataflowBlockOptions.EnsureOrdered)
{
reorderingBuffer = new ReorderingBuffer <IEnumerable <TOutput> >(
this, (source, messages) => ((TransformManyBlock <TInput, TOutput>)source)._source.AddMessages(messages));
}
// Create the underlying target and source
target = new TargetCore <TInput>(this, processMessageAction, _reorderingBuffer, dataflowBlockOptions, targetCoreOptions);
// Link up the target half with the source half. In doing so,
// ensure exceptions are propagated, and let the source know no more messages will arrive.
// As the target has completed, and as the target synchronously pushes work
// through the reordering buffer when async processing completes,
// we know for certain that no more messages will need to be sent to the source.
target.Completion.ContinueWith((completed, state) =>
{
var sourceCore = (SourceCore <TOutput>)state !;
if (completed.IsFaulted)
{
sourceCore.AddAndUnwrapAggregateException(completed.Exception !);
}
sourceCore.Complete();
}, source, CancellationToken.None, Common.GetContinuationOptions(), TaskScheduler.Default);
// 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.
source.Completion.ContinueWith((completed, state) =>
{
var thisBlock = ((TransformManyBlock <TInput, TOutput>)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);
// Handle async cancellation requests by declining on the target
Common.WireCancellationToComplete(
dataflowBlockOptions.CancellationToken, Completion, state => ((TargetCore <TInput>)state !).Complete(exception: null, dropPendingMessages: true), target);
DataflowEtwProvider etwLog = DataflowEtwProvider.Log;
if (etwLog.IsEnabled())
{
etwLog.DataflowBlockCreated(this, dataflowBlockOptions);
}
}