/
stopper.go
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/
stopper.go
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// Copyright 2017 clair authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package stopper
import (
"sync"
"time"
)
// Stopper eases the graceful termination of a group of goroutines
type Stopper struct {
wg sync.WaitGroup
stop chan struct{}
}
// NewStopper initializes a new Stopper instance
func NewStopper() *Stopper {
return &Stopper{stop: make(chan struct{}, 0)}
}
// Begin indicates that a new goroutine has started.
func (s *Stopper) Begin() {
s.wg.Add(1)
}
// End indicates that a goroutine has stopped.
func (s *Stopper) End() {
s.wg.Done()
}
// Chan returns the channel on which goroutines could listen to determine if
// they should stop. The channel is closed when Stop() is called.
func (s *Stopper) Chan() chan struct{} {
return s.stop
}
// Sleep puts the current goroutine on sleep during a duration d
// Sleep could be interrupted in the case the goroutine should stop itself,
// in which case Sleep returns false.
func (s *Stopper) Sleep(d time.Duration) bool {
select {
case <-time.After(d):
return true
case <-s.stop:
return false
}
}
// Stop asks every goroutine to end.
func (s *Stopper) Stop() {
close(s.stop)
s.wg.Wait()
}