单例双重检查引发的资源竞争/数据竞争

 1 type MemCache struct {
 2     data []string
 3 }
 4 
 5 var memCacheInstance *MemCache
 6 var memCacheCreateMutex sync.Mutex
 7 
 8 func GetMemCache() *MemCache {
 9     if memCacheInstance == nil {
10         memCacheCreateMutex.Lock()
11         defer memCacheCreateMutex.Unlock()
12 
13         if memCacheInstance == nil {
14             memCacheInstance = &MemCache{
15                 data: make([]string, 0),
16             }
17         }
18     }
19     return memCacheInstance
20 }