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package timingwheel
import (
"sync"
"time"
)
type TimingWheel struct {
sync.Mutex
interval time.Duration
ticker *time.Ticker
quit chan struct{}
maxTimeout time.Duration
cs []chan struct{}
pos int
}
func NewTimingWheel(interval time.Duration, buckets int) *TimingWheel {
w := new(TimingWheel)
w.interval = interval
w.quit = make(chan struct{})
w.pos = 0
w.maxTimeout = time.Duration(interval * (time.Duration(buckets)))
w.cs = make([]chan struct{}, buckets)
for i := range w.cs {
w.cs[i] = make(chan struct{})
}
w.ticker = time.NewTicker(interval)
go w.run()
return w
}
func (w *TimingWheel) Stop() {
close(w.quit)
}
func (w *TimingWheel) After(timeout time.Duration) <-chan struct{} {
if timeout >= w.maxTimeout {
panic("timeout too much, over maxtimeout")
}
index := int(timeout / w.interval)
if 0 < index {
index--
}
w.Lock()
index = (w.pos + index) % len(w.cs)
b := w.cs[index]
w.Unlock()
return b
}
func (w *TimingWheel) run() {
for {
select {
case <-w.ticker.C:
w.onTicker()
case <-w.quit:
w.ticker.Stop()
return
}
}
}
func (w *TimingWheel) onTicker() {
w.Lock()
lastC := w.cs[w.pos]
w.cs[w.pos] = make(chan struct{})
w.pos = (w.pos + 1) % len(w.cs)
w.Unlock()
close(lastC)
}
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