add redis lock~

Wenli.Drive.Redis/Core/SERedisLock.cs

@@ -6,6 +6,7 @@ namespace Wenli.Drive.Redis.Core
 {
     public partial class SERedisOperation : IRedisOperation
     {
+
         /// <summary>
         /// 锁超时时间，防止线程在入锁以后，无限的执行等待
         /// </summary>
@@ -17,35 +18,30 @@ public partial class SERedisOperation : IRedisOperation
 
 
         private static readonly string _prex = "lock_";
-        /**
-         * 获得 lock.
-         * 实现思路: 主要是使用了redis 的setnx命令,缓存了锁.
-         * reids缓存的key是锁的key,所有的共享, value是锁的到期时间(注意:这里把过期时间放在value了,没有时间上设置其超时时间)
-         * 执行过程:
-         * 1.通过setnx尝试设置某个key的值,成功(当前没有这个锁)则返回,成功获得锁
-         * 2.锁已经存在则获取锁的到期时间,和当前时间比较,超时的话,则设置新的值
-         *
-         * @return true if lock is acquired, false acquire timeouted
-         * @throws InterruptedException in case of thread interruption
-         */
 
+        /// <summary>
+        /// 利用StringSetIfNotExists实现锁
+        /// </summary>
+        /// <param name="key"></param>
+        /// <param name="timeout"></param>
+        /// <returns></returns>
         public bool Lock(string key, int timeout = 60 * 1000)
         {
             var lockKey = _prex + key;
 
             while (timeout > 0)
             {
-                long expires = DateTime.Now.Millisecond + _expireMsecs + 1;
+                long expires = DateTime.Now.AddMilliseconds(_expireMsecs).Ticks;
                 String expiresStr = expires.ToString();
                 if (this.StringSetIfNotExists(lockKey, expiresStr))
                 {
                     return true;
                 }
                 String currentValueStr = this.StringGet(lockKey);
-                if (currentValueStr != null && long.Parse(currentValueStr) < DateTime.Now.Millisecond)
+                if (currentValueStr != null && long.Parse(currentValueStr) <= DateTime.Now.Ticks)
                 {
                     String oldValueStr = this.StringGetSet(lockKey, expiresStr);
-                    if (oldValueStr != null && long.Parse(oldValueStr) <= long.Parse(currentValueStr))
+                    if (oldValueStr != null && oldValueStr == currentValueStr)
                     {
                         return true;
                     }