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