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// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
// +build darwin,kqueue darwin,!cgo dragonfly freebsd netbsd openbsd
package notify
import (
"fmt"
"os"
"syscall"
)
// newTrigger returns implementation of trigger.
func newTrigger(pthLkp map[string]*watched) trigger {
return &kq{
pthLkp: pthLkp,
idLkp: make(map[int]*watched),
}
}
// kq is a structure implementing trigger for kqueue.
type kq struct {
// fd is a kqueue file descriptor
fd int
// pipefds are file descriptors used to stop `Kevent` call.
pipefds [2]int
// idLkp is a data structure mapping file descriptors with data about watching
// represented by them files/directories.
idLkp map[int]*watched
// pthLkp is a structure mapping monitored files/dir with data about them,
// shared with parent trg structure
pthLkp map[string]*watched
}
// watched is a data structure representing watched file/directory.
type watched struct {
trgWatched
// fd is a file descriptor for watched file/directory.
fd int
}
// Stop implements trigger.
func (k *kq) Stop() (err error) {
// trigger event used to interrupt Kevent call.
_, err = syscall.Write(k.pipefds[1], []byte{0x00})
return
}
// Close implements trigger.
func (k *kq) Close() error {
return syscall.Close(k.fd)
}
// NewWatched implements trigger.
func (*kq) NewWatched(p string, fi os.FileInfo) (*watched, error) {
fd, err := syscall.Open(p, syscall.O_NONBLOCK|syscall.O_RDONLY, 0)
if err != nil {
// BSDs can't open symlinks and return an error if the symlink
// cannot be followed - ignore it instead of failing. See e.g.
// https://github.com/libinotify-kqueue/libinotify-kqueue/blob/a822c8f1d75404fe3132f695a898dcd42fe8afbc/patches/freebsd11-O_SYMLINK.patch
if os.IsNotExist(err) && fi.Mode()&os.ModeSymlink == os.ModeSymlink {
return nil, errSkip
}
return nil, err
}
return &watched{
trgWatched: trgWatched{p: p, fi: fi},
fd: fd,
}, nil
}
// Record implements trigger.
func (k *kq) Record(w *watched) {
k.idLkp[w.fd], k.pthLkp[w.p] = w, w
}
// Del implements trigger.
func (k *kq) Del(w *watched) {
syscall.Close(w.fd)
delete(k.idLkp, w.fd)
delete(k.pthLkp, w.p)
}
func inter2kq(n interface{}) syscall.Kevent_t {
kq, ok := n.(syscall.Kevent_t)
if !ok {
panic(fmt.Sprintf("kqueue: type should be Kevent_t, %T instead", n))
}
return kq
}
// Init implements trigger.
func (k *kq) Init() (err error) {
if k.fd, err = syscall.Kqueue(); err != nil {
return
}
// Creates pipe used to stop `Kevent` call by registering it,
// watching read end and writing to other end of it.
if err = syscall.Pipe(k.pipefds[:]); err != nil {
return nonil(err, k.Close())
}
var kevn [1]syscall.Kevent_t
syscall.SetKevent(&kevn[0], k.pipefds[0], syscall.EVFILT_READ, syscall.EV_ADD)
if _, err = syscall.Kevent(k.fd, kevn[:], nil, nil); err != nil {
return nonil(err, k.Close())
}
return
}
// Unwatch implements trigger.
func (k *kq) Unwatch(w *watched) (err error) {
var kevn [1]syscall.Kevent_t
syscall.SetKevent(&kevn[0], w.fd, syscall.EVFILT_VNODE, syscall.EV_DELETE)
_, err = syscall.Kevent(k.fd, kevn[:], nil, nil)
return
}
// Watch implements trigger.
func (k *kq) Watch(fi os.FileInfo, w *watched, e int64) (err error) {
var kevn [1]syscall.Kevent_t
syscall.SetKevent(&kevn[0], w.fd, syscall.EVFILT_VNODE,
syscall.EV_ADD|syscall.EV_CLEAR)
kevn[0].Fflags = uint32(e)
_, err = syscall.Kevent(k.fd, kevn[:], nil, nil)
return
}
// Wait implements trigger.
func (k *kq) Wait() (interface{}, error) {
var (
kevn [1]syscall.Kevent_t
err error
)
kevn[0] = syscall.Kevent_t{}
_, err = syscall.Kevent(k.fd, nil, kevn[:], nil)
return kevn[0], err
}
// Watched implements trigger.
func (k *kq) Watched(n interface{}) (*watched, int64, error) {
kevn, ok := n.(syscall.Kevent_t)
if !ok {
panic(fmt.Sprintf("kq: type should be syscall.Kevent_t, %T instead", kevn))
}
if _, ok = k.idLkp[int(kevn.Ident)]; !ok {
return nil, 0, errNotWatched
}
return k.idLkp[int(kevn.Ident)], int64(kevn.Fflags), nil
}
// IsStop implements trigger.
func (k *kq) IsStop(n interface{}, err error) bool {
return int(inter2kq(n).Ident) == k.pipefds[0]
}
func init() {
encode = func(e Event, dir bool) (o int64) {
// Create event is not supported by kqueue. Instead NoteWrite event will
// be registered for a directory. If this event will be reported on dir
// which is to be monitored for Create, dir will be rescanned
// and Create events will be generated and returned for new files.
// In case of files, if not requested NoteRename event is reported,
// it will be ignored.
o = int64(e &^ Create)
if (e&Create != 0 && dir) || e&Write != 0 {
o = (o &^ int64(Write)) | int64(NoteWrite)
}
if e&Rename != 0 {
o = (o &^ int64(Rename)) | int64(NoteRename)
}
if e&Remove != 0 {
o = (o &^ int64(Remove)) | int64(NoteDelete)
}
return
}
nat2not = map[Event]Event{
NoteWrite: Write,
NoteRename: Rename,
NoteDelete: Remove,
NoteExtend: Event(0),
NoteAttrib: Event(0),
NoteRevoke: Event(0),
NoteLink: Event(0),
}
not2nat = map[Event]Event{
Write: NoteWrite,
Rename: NoteRename,
Remove: NoteDelete,
}
}
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