You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
102 lines
2.1 KiB
102 lines
2.1 KiB
package common
|
|
|
|
import (
|
|
"time"
|
|
)
|
|
|
|
/*
|
|
RepeatTimer repeatedly sends a struct{}{} to .Ch after each "dur" period.
|
|
It's good for keeping connections alive.
|
|
A RepeatTimer must be Stop()'d or it will keep a goroutine alive.
|
|
*/
|
|
type RepeatTimer struct {
|
|
Name string
|
|
Ch <-chan time.Time
|
|
output chan<- time.Time
|
|
input chan repeatCommand
|
|
|
|
dur time.Duration
|
|
ticker *time.Ticker
|
|
stopped bool
|
|
}
|
|
|
|
type repeatCommand int8
|
|
|
|
const (
|
|
Reset repeatCommand = iota
|
|
RQuit
|
|
)
|
|
|
|
func NewRepeatTimer(name string, dur time.Duration) *RepeatTimer {
|
|
c := make(chan time.Time)
|
|
var t = &RepeatTimer{
|
|
Name: name,
|
|
Ch: c,
|
|
output: c,
|
|
input: make(chan repeatCommand),
|
|
|
|
dur: dur,
|
|
ticker: time.NewTicker(dur),
|
|
}
|
|
go t.run()
|
|
return t
|
|
}
|
|
|
|
// Wait the duration again before firing.
|
|
func (t *RepeatTimer) Reset() {
|
|
t.input <- Reset
|
|
}
|
|
|
|
// For ease of .Stop()'ing services before .Start()'ing them,
|
|
// we ignore .Stop()'s on nil RepeatTimers.
|
|
func (t *RepeatTimer) Stop() bool {
|
|
// use t.stopped to gracefully handle many Stop() without blocking
|
|
if t == nil || t.stopped {
|
|
return false
|
|
}
|
|
t.input <- RQuit
|
|
t.stopped = true
|
|
return true
|
|
}
|
|
|
|
func (t *RepeatTimer) run() {
|
|
done := false
|
|
for !done {
|
|
select {
|
|
case cmd := <-t.input:
|
|
// stop goroutine if the input says so
|
|
// don't close channels, as closed channels mess up select reads
|
|
done = t.processInput(cmd)
|
|
case tick := <-t.ticker.C:
|
|
t.send(tick)
|
|
}
|
|
}
|
|
}
|
|
|
|
// send performs blocking send on t.Ch
|
|
func (t *RepeatTimer) send(tick time.Time) {
|
|
// XXX: possibly it is better to not block:
|
|
// https://golang.org/src/time/sleep.go#L132
|
|
// select {
|
|
// case t.output <- tick:
|
|
// default:
|
|
// }
|
|
t.output <- tick
|
|
}
|
|
|
|
// all modifications of the internal state of ThrottleTimer
|
|
// happen in this method. It is only called from the run goroutine
|
|
// so we avoid any race conditions
|
|
func (t *RepeatTimer) processInput(cmd repeatCommand) (shutdown bool) {
|
|
switch cmd {
|
|
case Reset:
|
|
t.ticker.Stop()
|
|
t.ticker = time.NewTicker(t.dur)
|
|
case RQuit:
|
|
t.ticker.Stop()
|
|
shutdown = true
|
|
default:
|
|
panic("unknown command!")
|
|
}
|
|
return shutdown
|
|
}
|