semaphore.go

package semaphore

// Semaphore channel
type Semaphore chan struct{}

// Acquire resource
func (s Semaphore) Acquire() {
	s <- struct{}{}
}

// Release resource
func (s Semaphore) Release() {
	<-s
}

// Wait for completion
func (s Semaphore) Wait() {
	for i := 0; i < cap(s); i++ {
		s <- struct{}{}
	}
}

// Run `fn` in a goroutine, acquiring then releasing after its return
func (s Semaphore) Run(fn func()) {
	s.Acquire()
	go func() {
		defer s.Release()
		fn()
	}()
}