60 lines
1.2 KiB
Go
60 lines
1.2 KiB
Go
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package portlist
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import (
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"time"
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)
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type Poller struct {
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C chan List // new data when it arrives; closed when done
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quitCh chan struct{} // close this to force exit
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Err error // last returned error code, if any
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prev List // most recent data
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}
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func NewPoller() (*Poller, error) {
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p := &Poller{
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C: make(chan List),
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quitCh: make(chan struct{}),
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}
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// Do one initial poll synchronously, so the caller can react
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// to any obvious errors.
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p.prev, p.Err = GetList(nil)
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return p, p.Err
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}
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func (p *Poller) Close() {
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close(p.quitCh)
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<-p.C
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}
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// Poll periodically. Run this in a goroutine if you want.
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func (p *Poller) Run() error {
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defer close(p.C)
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tick := time.NewTicker(POLL_SECONDS * time.Second)
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defer tick.Stop()
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// Send out the pre-generated initial value
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p.C <- p.prev
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for {
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select {
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case <-tick.C:
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pl, err := GetList(p.prev)
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if err != nil {
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p.Err = err
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return p.Err
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}
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if !pl.SameInodes(p.prev) {
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p.prev = pl
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p.C <- pl
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}
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case <-p.quitCh:
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return nil
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}
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}
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}
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