.Netcore 使用CSRedis Lock分布式加锁原理

1.//使用方法

  using (var Lock = RedisHelper.Lock("锁名", "过期时间"))//返回CSRedisClientLock方法
            {
                if (Lock == null)
                {
                    return new Response().Fail("获取分布式锁失败");
                }
              //业务代码
            }//using结束默认调用CSRedisClientLock的Dispose方法，释放锁

2.//源代码分析

    public CSRedisClientLock Lock(string name, int timeoutSeconds, bool autoDelay = true)
        {
            name = $"CSRedisClientLock:{name}";
            var startTime = DateTime.Now;
            while (DateTime.Now.Subtract(startTime).TotalSeconds < timeoutSeconds)//通多过期时间循环去等待加锁
            {
                var value = Guid.NewGuid().ToString();
                if (this.Set(name, value, timeoutSeconds, RedisExistence.Nx) == true)//通过Redis Setnx设置锁也就是redis的 key value
                {
                    double refreshSeconds = (double)timeoutSeconds / 2.0;
                    return new CSRedisClientLock(this, name, value, timeoutSeconds, refreshSeconds, autoDelay);//返回CSRedisClientLock类
                }
                Thread.CurrentThread.Join(3);//加锁失败阻塞当前线程
            }
            return null;
        }
		
	public bool Set(string key, object value, TimeSpan expire, RedisExistence? exists = null)//通过Redis Setnx设置锁成功返回true失败返回false
        {
            object redisValule = this.SerializeRedisValueInternal(value);
            if (expire <= TimeSpan.Zero && exists == null) return ExecuteScalar(key, (c, k) => c.Value.Set(k, redisValule)) == "OK";
            if (expire <= TimeSpan.Zero && exists != null) return ExecuteScalar(key, (c, k) => c.Value.Set(k, redisValule, null, exists)) == "OK";
            if (expire > TimeSpan.Zero && exists == null) return ExecuteScalar(key, (c, k) => c.Value.Set(k, redisValule, expire, null)) == "OK";
            if (expire > TimeSpan.Zero && exists != null) return ExecuteScalar(key, (c, k) => c.Value.Set(k, redisValule, expire, exists)) == "OK";
            return false;
        }
		
    private static RedisStatus.Nullable Set(string key, object value, int? expirationSeconds = null, long? expirationMilliseconds = null, RedisExistence? exists = null)
        {
            var args = new List