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restic/internal/backend/semaphore.go
Alexander Neumann 6caeff2408 Run goimports
2017-07-23 14:21:03 +02:00

29 lines
585 B
Go

package backend
import "github.com/restic/restic/internal/errors"
// Semaphore limits access to a restricted resource.
type Semaphore struct {
ch chan struct{}
}
// NewSemaphore returns a new semaphore with capacity n.
func NewSemaphore(n uint) (*Semaphore, error) {
if n <= 0 {
return nil, errors.New("must be a positive number")
}
return &Semaphore{
ch: make(chan struct{}, n),
}, nil
}
// GetToken blocks until a Token is available.
func (s *Semaphore) GetToken() {
s.ch <- struct{}{}
}
// ReleaseToken returns a token.
func (s *Semaphore) ReleaseToken() {
<-s.ch
}