Jo Shields a575963da9 Imported Upstream version 3.6.0
Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14
2014-08-13 10:39:27 +01:00

67 lines
2.3 KiB
C#

// NullTargetBlock.cs
//
// Copyright (c) 2012 Petr Onderka
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
namespace System.Threading.Tasks.Dataflow {
/// <summary>
/// Target block returned by <see cref="DataflowBlock.NullTarget{TInput}"/>.
/// </summary>
class NullTargetBlock<TInput> : ITargetBlock<TInput> {
public NullTargetBlock ()
{
Completion = new TaskCompletionSource<bool> ().Task;
}
public DataflowMessageStatus OfferMessage (
DataflowMessageHeader messageHeader, TInput messageValue,
ISourceBlock<TInput> source, bool consumeToAccept)
{
if (!messageHeader.IsValid)
throw new ArgumentException ("The messageHeader is not valid.",
"messageHeader");
if (consumeToAccept && source == null)
throw new ArgumentException (
"consumeToAccept may only be true if provided with a non-null source.",
"consumeToAccept");
if (consumeToAccept) {
if (!source.ReserveMessage (messageHeader, this))
return DataflowMessageStatus.NotAvailable;
bool consummed;
source.ConsumeMessage (messageHeader, this, out consummed);
if (!consummed)
return DataflowMessageStatus.NotAvailable;
}
return DataflowMessageStatus.Accepted;
}
public Task Completion { get; private set; }
public void Complete ()
{
}
public void Fault (Exception exception)
{
}
}
}