harness-drone/queue/queue_impl.go

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2016-04-13 00:27:24 +00:00
package queue
import "sync"
type queue struct {
sync.Mutex
items map[*Work]struct{}
itemc chan *Work
}
func New() Queue {
return newQueue()
}
func newQueue() *queue {
return &queue{
items: make(map[*Work]struct{}),
itemc: make(chan *Work, 999),
}
}
func (q *queue) Publish(work *Work) error {
q.Lock()
q.items[work] = struct{}{}
q.Unlock()
q.itemc <- work
return nil
}
func (q *queue) Remove(work *Work) error {
q.Lock()
defer q.Unlock()
_, ok := q.items[work]
if !ok {
return ErrNotFound
}
var items []*Work
// loop through and drain all items
// from the
drain:
for {
select {
case item := <-q.itemc:
items = append(items, item)
default:
break drain
}
}
// re-add all items to the queue except
// the item we're trying to remove
for _, item := range items {
if item == work {
delete(q.items, work)
continue
}
q.itemc <- item
}
return nil
}
func (q *queue) Pull() *Work {
work := <-q.itemc
q.Lock()
delete(q.items, work)
q.Unlock()
return work
}
func (q *queue) PullClose(cn CloseNotifier) *Work {
for {
select {
case <-cn.CloseNotify():
return nil
case work := <-q.itemc:
q.Lock()
delete(q.items, work)
q.Unlock()
return work
}
}
}