mcs/class/System.Web.Mvc3/Mvc/Async/OperationCounter.cs

   1 namespace System.Web.Mvc.Async {
   2     using System;
   3     using System.Threading;
   4
   5     public sealed class OperationCounter {
   6
   7         private int _count;
   8
   9         public int Count {
  10             get {
  11                 return Thread.VolatileRead(ref _count);
  12             }
  13         }
  14
  15         public event EventHandler Completed;
  16
  17         private int AddAndExecuteCallbackIfCompleted(int value) {
  18             int newCount = Interlocked.Add(ref _count, value);
  19             if (newCount == 0) {
  20                 OnCompleted();
  21             }
  22
  23             return newCount;
  24         }
  25
  26         public int Decrement() {
  27             return AddAndExecuteCallbackIfCompleted(-1);
  28         }
  29
  30         public int Decrement(int value) {
  31             return AddAndExecuteCallbackIfCompleted(-value);
  32         }
  33
  34         public int Increment() {
  35             return AddAndExecuteCallbackIfCompleted(1);
  36         }
  37
  38         public int Increment(int value) {
  39             return AddAndExecuteCallbackIfCompleted(value);
  40         }
  41
  42         private void OnCompleted() {
  43             EventHandler handler = Completed;
  44             if (handler != null) {
  45                 handler(this, EventArgs.Empty);
  46             }
  47         }
  48
  49     }
  50 }