func (this *Consumer) Request(n int) (int64, error) {
if n < 1 {
return 0, ErrNotPositiveInteger
}
next, err := this.Get()
if err != nil {
return 0, err
}
nextSeq := next + int64(n)
cachedGate := this.cachedGate
if nextSeq > cachedGate {
var minSeq int64
var err error
for minSeq, err = ringbuffer.GetMinSeq(this.gates, math.MaxInt64); nextSeq > minSeq; minSeq, err = ringbuffer.GetMinSeq(this.gates, math.MaxInt64) {
//log.Printf("consumer nextSeq = %d, minSeq = %d\n", nextSeq, minSeq)
if err != nil {
return 0, err
}
runtime.Gosched()
}
this.cachedGate = minSeq
}
return nextSeq, nil
}
func (this *Producer) Request(n int) (int64, error) {
if n < 1 {
return 0, ErrNotPositiveInteger
}
cursor, err := this.Get()
if err != nil {
return 0, err
}
nextSeq := cursor + int64(n)
wrapPoint := nextSeq - int64(this.bufferSize)
cachedGate := this.cachedGate
//log.Printf("producer cursor = %d, nextSeq = %d, wrapPoint = %d, cachedGate = %d\n", cursor, nextSeq, wrapPoint, cachedGate)
// For the producer, cachedGate is the previous lowest consumer sequence. If wrapPoint
// is greater than cacehdGate, that means the consumer has't reached the next slot yet,
// which means we cannot do anything// with that slot until all the consumers have
// passed it. So we wait...
//
// TODO: Figure out what "cachedGate > next" means
if wrapPoint > cachedGate || cachedGate > cursor {
var minSeq int64
var err error
for minSeq, err = ringbuffer.GetMinSeq(this.gates, cursor); wrapPoint > minSeq; minSeq, err = ringbuffer.GetMinSeq(this.gates, cursor) {
if err != nil {
return 0, err
}
//runtime.Gosched()
}
this.cachedGate = minSeq
}
return nextSeq, nil
}