共享资源锁 [英] Shared Resource Lock

问题描述

我在.NET 4.5-Web API自助主机上使用C#.服务器端我有一个进程不是线程安全的:它一次只能处理一个请求.如何在控制器代码中锁定此资源(进程)，以便按顺序为客户端提供服务，等待资源释放后再使用它?像这样:

I'm using C# on .NET 4.5 - Web API Self Host. Server-side I've a process that is not thread safe: it can serve one request at a time. How can I lock this resource (process) in the controller code, so that clients are served sequentially, waiting for the resource to be freed before using it? Something like:

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

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

任何代码段或建议都值得赞赏.预先感谢.

Any code snippet or suggestion are appreciated. Thanks in advance.

推荐答案

如果您要查找要执行的每个线程，但一次只能执行一个，则可以将 lock 语句与静态对象:

If you're looking for each thread to execute, but only one at a time, then you can use the lock statement with a static object:

private static object lockobj = new object();

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

如果您希望线程在对象被锁定时立即返回，则可以这样编写它(双重检查锁定):

If you want the thread to return immediately if the object is locked, then you can write it like this (double-checked locking):

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);
}

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