A fsnotify-powered watcher for Go that supports adding listeners

watcher.go

package main

import (
	"log"
	"github.com/fsnotify/fsnotify"
)

type CB func(Event)

type Event struct {
	fsnotify.Event
}

func (e Event) IsCreate() bool {
	return e.Op&fsnotify.Create == fsnotify.Create
}

func (e Event) IsWrite() bool {
	return e.Op&fsnotify.Write == fsnotify.Write
}

func (e Event) IsRemove() bool {
	return e.Op&fsnotify.Remove == fsnotify.Remove
}

func (e Event) IsRename() bool {
	return e.Op&fsnotify.Rename == fsnotify.Rename
}

func (e Event) IsChmod() bool {
	return e.Op&fsnotify.Chmod == fsnotify.Chmod
}

type Watcher struct {
	*fsnotify.Watcher
	done chan bool
	listeners []CB
}

func NewWatcher() (*Watcher, error) {
	watcher, err := fsnotify.NewWatcher()
	return &Watcher{watcher, make(chan bool), make([]CB, 0)}, err
}

func (w *Watcher) AddListener(cb CB) {
	w.listeners = append(w.listeners, cb)
}

// Start listening for file changes asynchronously
func (w *Watcher) Listen() {
	w.done = make(chan bool)
	go func() {
		for {
			select {
			case event, ok := <-w.Events:
				if !ok {
					return
				}
				for _, cb := range w.listeners {
					cb(Event{event})
				}
			case err, ok := <-w.Errors:
				if !ok {
					return
				}
				log.Println("error:", err)
			case <-w.done:
				return
			}
		}
	}()
}

// Stop listening for changes
func (w *Watcher) Stop() {
	w.done <- true
}