trylock.go

package trylock

import "sync/atomic"

// Mutex trylock的mutex
type Mutex struct {
	v int32
}

// TryLock 尝试获取锁，取不到则返回false
func (m *Mutex) TryLock() bool {
	return atomic.CompareAndSwapInt32(&m.v, 0, 1)
}

// Unlock 解锁
func (m *Mutex) Unlock() {
	atomic.StoreInt32(&m.v, 0)
}

trylock_test.go

package trylock

import (
	"sync"
	"testing"
)

func TestLock(t *testing.T) {
	m := &Mutex{}
	if m.v != 0 {
		t.Fatal("v should be 0")
	}
	wg := &sync.WaitGroup{}
	wg.Add(1)

	wg2 := &sync.WaitGroup{}
	wg2.Add(1)

	go func() {
		locked := m.TryLock()
		if !locked {
			t.Fatal("should be success")
		}
		if m.v != 1 {
			t.Fatal("v should be 1")
		}

		wg2.Done()

		wg.Wait()

		defer m.Unlock()
	}()

	wg2.Wait()

	if m.v != 1 {
		t.Fatal("v should be 1")
	}

	go func() {
		locked := m.TryLock()
		if locked {
			t.Fatal("should be failed")
		}
	}()

	wg.Done()

}