/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc.Async{
using System;
using System.Threading;
public sealed class OperationCounter {
private int _count;
public int Count {
get {
return Thread.VolatileRead(ref _count);
}
}
public event EventHandler Completed;
private int AddAndExecuteCallbackIfCompleted(int value) {
int newCount = Interlocked.Add(ref _count, value);
if (newCount == 0) {
OnCompleted();
}
return newCount;
}
public int Decrement() {
return AddAndExecuteCallbackIfCompleted(-1);
}
public int Decrement(int value) {
return AddAndExecuteCallbackIfCompleted(-value);
}
public int Increment() {
return AddAndExecuteCallbackIfCompleted(1);
}
public int Increment(int value) {
return AddAndExecuteCallbackIfCompleted(value);
}
private void OnCompleted() {
EventHandler handler = Completed;
if (handler != null) {
handler(this, EventArgs.Empty);
}
}
}
}
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