/// <summary>Initializes the debug view.</summary>
/// <param name="actionBlock">The target being debugged.</param>
public DebugView(ActionBlock <TInput> actionBlock)
{
Contract.Requires(actionBlock != null, "Need a block with which to construct the debug view.");
_actionBlock = actionBlock;
if (_actionBlock._defaultTarget != null)
{
_defaultDebugInfo = actionBlock._defaultTarget.GetDebuggingInformation();
}
else
{
_spscDebugInfo = actionBlock._spscTarget.GetDebuggingInformation();
}
}
/// <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
}
