共享资源锁

Question

我在.NET 4.5上使用C# - Web API Self Host.服务器端我有一个非线程安全的进程:它可以一次处理一个请求.如何在控制器代码中锁定此资源(进程),以便顺序提供客户端,等待资源在使用之前被释放？就像是:

while(true){
    if(!process.isLocked)
        break;
}

lock(process)
do(work)
unlock(process)
warn(others)

任何代码段或建议都表示赞赏.提前致谢.

Answer 1

如果您正在寻找要执行的每个线程,但一次只能查找一个,那么您可以将该lock语句与静态对象一起使用:

private static object lockobj = new object();

public void DoWorkWhenNotBusy()
{
    lock (lockobj)
    {
        // do work
        Console.WriteLine("Working #1 (should always complete)...");
        Thread.Sleep(500);
    }
}

如果你希望线程在对象被锁定时立即返回,那么你可以这样写(双重检查锁定):

private static object lockobj2 = new object();
private volatile bool locked = false;

public void DoWorkIfNotBusy()
{
    if (!locked)
    {
        lock (lockobj2)
        {
            if (!locked)
            {
                locked = true;
                // do work
                Thread.Sleep(500);
                Console.WriteLine("Working #2 (only if not busy)...");
            }
            locked = false;
        }
    }
}

测试示例:

for (int i = 0; i < 10; i++)
{
    var ts = new ThreadStart(DoWorkWhenNotBusy);
    Thread t = new Thread(ts);
    t.Start();

    var ts2 = new ThreadStart(DoWorkIfNotBusy);
    Thread t2 = new Thread(ts2);
    t2.Start();

    Console.WriteLine("{0} started", i);
}