github.com/alibaba/sentinel-golang@v1.0.4/core/stat/base/mutex.go (about)

     1  // Copyright 1999-2020 Alibaba Group Holding Ltd.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package base
    16  
    17  import (
    18  	"sync"
    19  	"sync/atomic"
    20  	"unsafe"
    21  )
    22  
    23  const mutexLocked = 1 << iota
    24  
    25  // The mutex which supports try-locking.
    26  type mutex struct {
    27  	sync.Mutex
    28  }
    29  
    30  // TryLock acquires the lock only if it is free at the time of invocation.
    31  func (tl *mutex) TryLock() bool {
    32  	return atomic.CompareAndSwapInt32((*int32)(unsafe.Pointer(&tl.Mutex)), 0, mutexLocked)
    33  }