integrate inotify syscalls

internal/inotify/inotify.go

@@ -0,0 +1,65 @@
+package inotify
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+type Inotify struct {
+	fd       int
+	watchers []*watcher
+	ping     chan struct{}
+	paused   bool
+}
+
+func NewInotify(ping chan struct{}) (*Inotify, error) {
+	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
+	if fd == -1 {
+		return nil, fmt.Errorf("Can't init inotify: %d", errno)
+	}
+
+	i := &Inotify{
+		fd:     fd,
+		ping:   ping,
+		paused: false,
+	}
+	go watch(i)
+
+	return i, nil
+}
+
+func (i *Inotify) Watch(dir string) error {
+	w, err := newWatcher(i.fd, dir, i.ping)
+	if err != nil {
+		return fmt.Errorf("creating watcher: %v", err)
+	}
+	i.watchers = append(i.watchers, w)
+	return nil
+}
+
+func (i *Inotify) Pause() {
+	i.paused = true
+}
+
+func (i *Inotify) UnPause() {
+	i.paused = false
+}
+
+func (i *Inotify) String() string {
+	dirs := make([]string, 0)
+	for _, w := range i.watchers {
+		dirs = append(dirs, w.dir)
+	}
+	return fmt.Sprintf("Watching: %v", dirs)
+}
+
+func watch(i *Inotify) {
+	buf := make([]byte, 1024)
+	for {
+		_, _ = unix.Read(i.fd, buf)
+		if !i.paused {
+			i.ping <- struct{}{}
+		}
+	}
+}

internal/inotify/watcher.go

@@ -0,0 +1,25 @@
+package inotify
+
+import (
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+const events = unix.IN_ALL_EVENTS
+
+type watcher struct {
+	wd  int
+	dir string
+}
+
+func newWatcher(fd int, dir string, ping chan struct{}) (*watcher, error) {
+	wd, errno := unix.InotifyAddWatch(fd, dir, events)
+	if wd == -1 {
+		return nil, fmt.Errorf("adding watcher on %s: %d", dir, errno)
+	}
+	return &watcher{
+		wd:  wd,
+		dir: dir,
+	}, nil
+}