зеркало из https://github.com/github/codeql.git
43 строки
615 B
Go
43 строки
615 B
Go
package extractor
|
|
|
|
import (
|
|
"log"
|
|
)
|
|
|
|
type Unit struct{}
|
|
|
|
var unit = Unit{}
|
|
|
|
type semaphore struct {
|
|
counter, lock chan Unit
|
|
}
|
|
|
|
func (s *semaphore) acquire(n int) {
|
|
if s != nil {
|
|
if cap(s.counter) < n {
|
|
log.Fatalf("Tried to acquire more resources than were available.")
|
|
}
|
|
s.lock <- unit
|
|
for i := 0; i < n; i++ {
|
|
s.counter <- unit
|
|
}
|
|
<-s.lock
|
|
}
|
|
}
|
|
|
|
func (s *semaphore) release(n int) {
|
|
if s != nil {
|
|
for i := 0; i < n; i++ {
|
|
<-s.counter
|
|
}
|
|
}
|
|
}
|
|
|
|
func newSemaphore(max int) *semaphore {
|
|
if max > 0 {
|
|
return &semaphore{make(chan Unit, max), make(chan Unit, 1)}
|
|
} else {
|
|
return nil
|
|
}
|
|
}
|