sync.go (498B)
1 package sync 2 3 type Semaphore struct { 4 ch chan struct{} 5 } 6 7 func NewSemaphore(size int) Semaphore { 8 return Semaphore{ 9 ch: make(chan struct{}, size), 10 } 11 } 12 13 func (sem Semaphore) Acquire() { 14 sem.ch <- struct{}{} 15 } 16 17 func (sem Semaphore) AcquireMaybe() bool { 18 select { 19 case sem.ch <- struct{}{}: 20 return true 21 default: 22 return false 23 } 24 } 25 26 func (sem Semaphore) Release() { 27 <-sem.ch 28 } 29 30 func (sem Semaphore) Len() int { 31 return len(sem.ch) 32 } 33 34 func (sem Semaphore) Cap() int { 35 return cap(sem.ch) 36 }