輕量級 Lock Free 安全執行緒的 Queue 的C#2.0實現

最近在維護一些C# 2.0的代碼....發現各種線程不安全的實現

2.0裡面又沒有ConcurrentCollection的相關類

不得已,自己寫了一個,

本來想用傳統的lock實現的, 不過考慮到其中的操作非常輕量級...最終還是用了Lock Free

使用原子操作 InterLocked 替換掉常用的lock關鍵字

    public sealed class SafedQueue<T>
    {
#region private Fields
private int isTaked = 0;
private Queue<T> queue = new Queue<T>();
private int MaxCount = 1000 * 1000;
#endregion

public void Enqueue(T t)
        {
try
            {
while (Interlocked.Exchange(ref isTaked, 1) != 0)
                {
                }
this.queue.Enqueue(t);
            }
finally
            {
                Thread.VolatileWrite(ref isTaked, 0);
            }
        }

public T Dequeue()
        {
try
            {
while (Interlocked.Exchange(ref isTaked, 1) != 0)
                {
                }
                T t = this.queue.Dequeue();
return t;
            }
finally
            {
                Thread.VolatileWrite(ref isTaked, 0);
            }
        }

public bool TryEnqueue(T t)
        {
try
            {
for (int i = 0; i < MaxCount; i++)
                {
if (Interlocked.Exchange(ref isTaked, 1) == 0)
                    {
this.queue.Enqueue(t);
return true;
                    }
                }
return false;
            }
finally
            {
                Thread.VolatileWrite(ref isTaked, 0);
            }
        }

public bool TryDequeue(out T t)
        {
try
            {
for (int i = 0; i < MaxCount; i++)
                {
if (Interlocked.Exchange(ref isTaked, 1) == 0)
                    {
                        t = this.queue.Dequeue();
return true;
                    }
                }
                t = default(T);
return false;
            }
finally
            {
                Thread.VolatileWrite(ref isTaked, 0);
            }
        }
    }

Try起頭的方法都有嘗試次數限制,超過限制以後就退出並返回false