func WatchForUpdates()

in watcher.go [33:68]

• 31 lines of code
• 8 McCabe index (conditional complexity)

func WatchForUpdates(filename string, done <-chan bool, action func()) {
	filename = filepath.Clean(filename)
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal("failed to create watcher for ", filename, ": ", err)
	}
	go func() {
		defer watcher.Close()
		for {
			select {
			case _ = <-done:
				log.Printf("Shutting down watcher for: %s", filename)
				break
			case event := <-watcher.Events:
				// On Arch Linux, it appears Chmod events precede Remove events,
				// which causes a race between action() and the coming Remove event.
				// If the Remove wins, the action() (which calls
				// UserMap.LoadAuthenticatedEmailsFile()) crashes when the file
				// can't be opened.
				if event.Op&(fsnotify.Remove|fsnotify.Rename|fsnotify.Chmod) != 0 {
					log.Printf("watching interrupted on event: %s", event)
					watcher.Remove(filename)
					WaitForReplacement(filename, event.Op, watcher)
				}
				log.Printf("reloading after event: %s", event)
				action()
			case err := <-watcher.Errors:
				log.Printf("error watching %s: %s", filename, err)
			}
		}
	}()
	if err = watcher.Add(filename); err != nil {
		log.Fatal("failed to add ", filename, " to watcher: ", err)
	}
	log.Printf("watching %s for updates", filename)
}