Golang Chan implements mutual exclusion

//  Use chan Implement mutually exclusive lock 
type Mutex struct {
    
    ch chan struct{
    }
}

//  Using locks requires initialization 
func NewMutex() *Mutex {
    
    mu := &Mutex{
    make(chan struct{
    }, 1)}
    mu.ch <- struct{
    }{
    }
    return mu
}

//  Request lock , Until you get 
func (m *Mutex) Lock() {
    
    <-m.ch
}

//  Unlock 
func (m *Mutex) Unlock() {
    
    select {
    
    case m.ch <- struct{
    }{
    }:
    default:
        panic("unlock of unlocked mutex")
    }
}

//  Attempt to acquire lock 
func (m *Mutex) TryLock() bool {
    
    select {
    
    case <-m.ch:
        return true
    default:
    }
    return false
}

//  Add a timeout setting 
func (m *Mutex) LockTimeout(timeout time.Duration) bool {
    
    timer := time.NewTimer(timeout)
    select {
    
    case <-m.ch:
        timer.Stop()
        return true
    case <-timer.C:
    }
    return false
}

//  Whether the lock has been held 
func (m *Mutex) IsLocked() bool {
    
    return len(m.ch) == 0
}


func main() {
    
    m := NewMutex()
    ok := m.TryLock()
    fmt.Printf("locked v %v\n", ok)
    ok = m.TryLock()
    fmt.Printf("locked %v\n", ok)
}