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86 lines
1.6 KiB
86 lines
1.6 KiB
package common
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import (
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"sync"
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"time"
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)
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/*
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RepeatTimer repeatedly sends a struct{}{} to .Ch after each "dur" period.
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It's good for keeping connections alive.
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A RepeatTimer must be Stop()'d or it will keep a goroutine alive.
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*/
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type RepeatTimer struct {
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Ch chan time.Time
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mtx sync.Mutex
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name string
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ticker *time.Ticker
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quit chan struct{}
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wg *sync.WaitGroup
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dur time.Duration
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}
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func NewRepeatTimer(name string, dur time.Duration) *RepeatTimer {
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var t = &RepeatTimer{
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Ch: make(chan time.Time),
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ticker: time.NewTicker(dur),
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quit: make(chan struct{}),
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wg: new(sync.WaitGroup),
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name: name,
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dur: dur,
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}
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t.wg.Add(1)
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go t.fireRoutine(t.ticker)
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return t
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}
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func (t *RepeatTimer) fireRoutine(ticker *time.Ticker) {
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for {
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select {
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case t_ := <-ticker.C:
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t.Ch <- t_
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case <-t.quit:
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// needed so we know when we can reset t.quit
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t.wg.Done()
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return
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}
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}
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}
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// Wait the duration again before firing.
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func (t *RepeatTimer) Reset() {
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t.Stop()
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t.mtx.Lock() // Lock
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defer t.mtx.Unlock()
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t.ticker = time.NewTicker(t.dur)
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t.quit = make(chan struct{})
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t.wg.Add(1)
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go t.fireRoutine(t.ticker)
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}
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// For ease of .Stop()'ing services before .Start()'ing them,
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// we ignore .Stop()'s on nil RepeatTimers.
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func (t *RepeatTimer) Stop() bool {
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if t == nil {
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return false
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}
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t.mtx.Lock() // Lock
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defer t.mtx.Unlock()
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exists := t.ticker != nil
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if exists {
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t.ticker.Stop() // does not close the channel
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select {
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case <-t.Ch:
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// read off channel if there's anything there
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default:
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}
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close(t.quit)
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t.wg.Wait() // must wait for quit to close else we race Reset
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t.ticker = nil
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}
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return exists
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}
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