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package common
import (
"sync/atomic"
"time"
)
/*
ThrottleTimer fires an event at most "dur" after each .Set() call.
If a short burst of .Set() calls happens, ThrottleTimer fires once.
If a long continuous burst of .Set() calls happens, ThrottleTimer fires
at most once every "dur".
*/
type ThrottleTimer struct {
Name string
Ch chan struct{}
quit chan struct{}
dur time.Duration
timer *time.Timer
isSet uint32
}
func NewThrottleTimer(name string, dur time.Duration) *ThrottleTimer {
var ch = make(chan struct{})
var quit = make(chan struct{})
var t = &ThrottleTimer{Name: name, Ch: ch, dur: dur, quit: quit}
t.timer = time.AfterFunc(dur, t.fireRoutine)
t.timer.Stop()
return t
}
func (t *ThrottleTimer) fireRoutine() {
select {
case t.Ch <- struct{}{}:
atomic.StoreUint32(&t.isSet, 0)
case <-t.quit:
// do nothing
default:
t.timer.Reset(t.dur)
}
}
func (t *ThrottleTimer) Set() {
if atomic.CompareAndSwapUint32(&t.isSet, 0, 1) {
t.timer.Reset(t.dur)
}
}
// For ease of .Stop()'ing services before .Start()'ing them,
// we ignore .Stop()'s on nil ThrottleTimers
func (t *ThrottleTimer) Stop() bool {
if t == nil {
return false
}
close(t.quit)
return t.timer.Stop()
}