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queue.go
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/
queue.go
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package binding
var itemQueueIn, itemQueueOut = makeInfiniteQueue()
type itemData struct {
fn func()
done chan interface{}
}
func queueItem(f func()) {
itemQueueIn <- &itemData{fn: f}
}
func init() {
go processItems()
}
func makeInfiniteQueue() (chan<- *itemData, <-chan *itemData) {
in := make(chan *itemData)
out := make(chan *itemData)
go func() {
queued := make([]*itemData, 0, 1024)
pending := func() chan *itemData {
if len(queued) == 0 {
return nil
}
return out
}
next := func() *itemData {
if len(queued) == 0 {
return nil
}
return queued[0]
}
for len(queued) > 0 || in != nil {
select {
case val, ok := <-in:
if !ok {
in = nil
} else {
queued = append(queued, val)
}
case pending() <- next():
queued = queued[1:]
}
}
close(out)
}()
return in, out
}
func processItems() {
for {
i := <-itemQueueOut
if i.fn != nil {
i.fn()
}
if i.done != nil {
i.done <- struct{}{}
}
}
}
func waitForItems() {
done := make(chan interface{})
itemQueueIn <- &itemData{done: done}
<-done
}