traefik/vendor/github.com/eapache/channels/black_hole.go

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2017-02-07 21:33:23 +00:00
package channels
// BlackHole implements the InChannel interface and provides an analogue for the "Discard" variable in
// the ioutil package - it never blocks, and simply discards every value it reads. The number of items
// discarded in this way is counted and returned from Len.
type BlackHole struct {
input chan interface{}
length chan int
count int
}
func NewBlackHole() *BlackHole {
ch := &BlackHole{
input: make(chan interface{}),
length: make(chan int),
}
go ch.discard()
return ch
}
func (ch *BlackHole) In() chan<- interface{} {
return ch.input
}
func (ch *BlackHole) Len() int {
val, open := <-ch.length
if open {
return val
} else {
return ch.count
}
}
func (ch *BlackHole) Cap() BufferCap {
return Infinity
}
func (ch *BlackHole) Close() {
close(ch.input)
}
func (ch *BlackHole) discard() {
for {
select {
case _, open := <-ch.input:
if !open {
close(ch.length)
return
}
ch.count++
case ch.length <- ch.count:
}
}
}