1 files changed, 319 insertions, 0 deletions
diff --git a/vendor/github.com/rjeczalik/notify/watcher_fsevents.go b/vendor/github.com/rjeczalik/notify/watcher_fsevents.go
new file mode 100644
index 000000000..9062c17c7
--- /dev/null
+++ b/vendor/github.com/rjeczalik/notify/watcher_fsevents.go
@@ -0,0 +1,319 @@
+// 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
+
+package notify
+
+import (
+	"errors"
+	"strings"
+	"sync/atomic"
+)
+
+// TODO(rjeczalik): get rid of calls to canonical, it's tree responsibility
+
+const (
+	failure = uint32(FSEventsMustScanSubDirs | FSEventsUserDropped | FSEventsKernelDropped)
+	filter  = uint32(FSEventsCreated | FSEventsRemoved | FSEventsRenamed |
+		FSEventsModified | FSEventsInodeMetaMod)
+)
+
+// FSEvent represents single file event. It is created out of values passed by
+// FSEvents to FSEventStreamCallback function.
+type FSEvent struct {
+	Path  string // real path of the file or directory
+	ID    uint64 // ID of the event (FSEventStreamEventId)
+	Flags uint32 // joint FSEvents* flags (FSEventStreamEventFlags)
+}
+
+// splitflags separates event flags from single set into slice of flags.
+func splitflags(set uint32) (e []uint32) {
+	for i := uint32(1); set != 0; i, set = i<<1, set>>1 {
+		if (set & 1) != 0 {
+			e = append(e, i)
+		}
+	}
+	return
+}
+
+// watch represents a filesystem watchpoint. It is a higher level abstraction
+// over FSEvents' stream, which implements filtering of file events based
+// on path and event set. It emulates non-recursive watch-point by filtering out
+// events which paths are more than 1 level deeper than the watched path.
+type watch struct {
+	// prev stores last event set  per path in order to filter out old flags
+	// for new events, which appratenly FSEvents likes to retain. It's a disgusting
+	// hack, it should be researched how to get rid of it.
+	prev    map[string]uint32
+	c       chan<- EventInfo
+	stream  *stream
+	path    string
+	events  uint32
+	isrec   int32
+	flushed bool
+}
+
+// Example format:
+//
+//   ~ $ (trigger command) # (event set) -> (effective event set)
+//
+// Heuristics:
+//
+// 1. Create event is removed when it was present in previous event set.
+// Example:
+//
+//   ~ $ echo > file # Create|Write -> Create|Write
+//   ~ $ echo > file # Create|Write|InodeMetaMod -> Write|InodeMetaMod
+//
+// 2. Remove event is removed if it was present in previouse event set.
+// Example:
+//
+//   ~ $ touch file # Create -> Create
+//   ~ $ rm file    # Create|Remove -> Remove
+//   ~ $ touch file # Create|Remove -> Create
+//
+// 3. Write event is removed if not followed by InodeMetaMod on existing
+// file. Example:
+//
+//   ~ $ echo > file   # Create|Write -> Create|Write
+//   ~ $ chmod +x file # Create|Write|ChangeOwner -> ChangeOwner
+//
+// 4. Write&InodeMetaMod is removed when effective event set contain Remove event.
+// Example:
+//
+//   ~ $ echo > file # Write|InodeMetaMod -> Write|InodeMetaMod
+//   ~ $ rm file     # Remove|Write|InodeMetaMod -> Remove
+//
+func (w *watch) strip(base string, set uint32) uint32 {
+	const (
+		write = FSEventsModified | FSEventsInodeMetaMod
+		both  = FSEventsCreated | FSEventsRemoved
+	)
+	switch w.prev[base] {
+	case FSEventsCreated:
+		set &^= FSEventsCreated
+		if set&FSEventsRemoved != 0 {
+			w.prev[base] = FSEventsRemoved
+			set &^= write
+		}
+	case FSEventsRemoved:
+		set &^= FSEventsRemoved
+		if set&FSEventsCreated != 0 {
+			w.prev[base] = FSEventsCreated
+		}
+	default:
+		switch set & both {
+		case FSEventsCreated:
+			w.prev[base] = FSEventsCreated
+		case FSEventsRemoved:
+			w.prev[base] = FSEventsRemoved
+			set &^= write
+		}
+	}
+	dbgprintf("split()=%v\n", Event(set))
+	return set
+}
+
+// Dispatch is a stream function which forwards given file events for the watched
+// path to underlying FileInfo channel.
+func (w *watch) Dispatch(ev []FSEvent) {
+	events := atomic.LoadUint32(&w.events)
+	isrec := (atomic.LoadInt32(&w.isrec) == 1)
+	for i := range ev {
+		if ev[i].Flags&FSEventsHistoryDone != 0 {
+			w.flushed = true
+			continue
+		}
+		if !w.flushed {
+			continue
+		}
+		dbgprintf("%v (0x%x) (%s, i=%d, ID=%d, len=%d)\n", Event(ev[i].Flags),
+			ev[i].Flags, ev[i].Path, i, ev[i].ID, len(ev))
+		if ev[i].Flags&failure != 0 {
+			// TODO(rjeczalik): missing error handling
+			continue
+		}
+		if !strings.HasPrefix(ev[i].Path, w.path) {
+			continue
+		}
+		n := len(w.path)
+		base := ""
+		if len(ev[i].Path) > n {
+			if ev[i].Path[n] != '/' {
+				continue
+			}
+			base = ev[i].Path[n+1:]
+			if !isrec && strings.IndexByte(base, '/') != -1 {
+				continue
+			}
+		}
+		// TODO(rjeczalik): get diff only from filtered events?
+		e := w.strip(string(base), ev[i].Flags) & events
+		if e == 0 {
+			continue
+		}
+		for _, e := range splitflags(e) {
+			dbgprintf("%d: single event: %v", ev[i].ID, Event(e))
+			w.c <- &event{
+				fse:   ev[i],
+				event: Event(e),
+			}
+		}
+	}
+}
+
+// Stop closes underlying FSEvents stream and stops dispatching events.
+func (w *watch) Stop() {
+	w.stream.Stop()
+	// TODO(rjeczalik): make (*stream).Stop flush synchronously undelivered events,
+	// so the following hack can be removed. It should flush all the streams
+	// concurrently as we care not to block too much here.
+	atomic.StoreUint32(&w.events, 0)
+	atomic.StoreInt32(&w.isrec, 0)
+}
+
+// fsevents implements Watcher and RecursiveWatcher interfaces backed by FSEvents
+// framework.
+type fsevents struct {
+	watches map[string]*watch
+	c       chan<- EventInfo
+}
+
+func newWatcher(c chan<- EventInfo) watcher {
+	return &fsevents{
+		watches: make(map[string]*watch),
+		c:       c,
+	}
+}
+
+func (fse *fsevents) watch(path string, event Event, isrec int32) (err error) {
+	if path, err = canonical(path); err != nil {
+		return err
+	}
+	if _, ok := fse.watches[path]; ok {
+		return errAlreadyWatched
+	}
+	w := &watch{
+		prev:   make(map[string]uint32),
+		c:      fse.c,
+		path:   path,
+		events: uint32(event),
+		isrec:  isrec,
+	}
+	w.stream = newStream(path, w.Dispatch)
+	if err = w.stream.Start(); err != nil {
+		return err
+	}
+	fse.watches[path] = w
+	return nil
+}
+
+func (fse *fsevents) unwatch(path string) (err error) {
+	if path, err = canonical(path); err != nil {
+		return
+	}
+	w, ok := fse.watches[path]
+	if !ok {
+		return errNotWatched
+	}
+	w.stream.Stop()
+	delete(fse.watches, path)
+	return nil
+}
+
+// Watch implements Watcher interface. It fails with non-nil error when setting
+// the watch-point by FSEvents fails or with errAlreadyWatched error when
+// the given path is already watched.
+func (fse *fsevents) Watch(path string, event Event) error {
+	return fse.watch(path, event, 0)
+}
+
+// Unwatch implements Watcher interface. It fails with errNotWatched when
+// the given path is not being watched.
+func (fse *fsevents) Unwatch(path string) error {
+	return fse.unwatch(path)
+}
+
+// Rewatch implements Watcher interface. It fails with errNotWatched when
+// the given path is not being watched or with errInvalidEventSet when oldevent
+// does not match event set the watch-point currently holds.
+func (fse *fsevents) Rewatch(path string, oldevent, newevent Event) error {
+	w, ok := fse.watches[path]
+	if !ok {
+		return errNotWatched
+	}
+	if !atomic.CompareAndSwapUint32(&w.events, uint32(oldevent), uint32(newevent)) {
+		return errInvalidEventSet
+	}
+	atomic.StoreInt32(&w.isrec, 0)
+	return nil
+}
+
+// RecursiveWatch implements RecursiveWatcher interface. It fails with non-nil
+// error when setting the watch-point by FSEvents fails or with errAlreadyWatched
+// error when the given path is already watched.
+func (fse *fsevents) RecursiveWatch(path string, event Event) error {
+	return fse.watch(path, event, 1)
+}
+
+// RecursiveUnwatch implements RecursiveWatcher interface. It fails with
+// errNotWatched when the given path is not being watched.
+//
+// TODO(rjeczalik): fail if w.isrec == 0?
+func (fse *fsevents) RecursiveUnwatch(path string) error {
+	return fse.unwatch(path)
+}
+
+// RecrusiveRewatch implements RecursiveWatcher interface. It fails:
+//
+//   * with errNotWatched when the given path is not being watched
+//   * with errInvalidEventSet when oldevent does not match the current event set
+//   * with errAlreadyWatched when watch-point given by the oldpath was meant to
+//     be relocated to newpath, but the newpath is already watched
+//   * a non-nil error when setting the watch-point with FSEvents fails
+//
+// TODO(rjeczalik): Improve handling of watch-point relocation? See two TODOs
+// that follows.
+func (fse *fsevents) RecursiveRewatch(oldpath, newpath string, oldevent, newevent Event) error {
+	switch [2]bool{oldpath == newpath, oldevent == newevent} {
+	case [2]bool{true, true}:
+		w, ok := fse.watches[oldpath]
+		if !ok {
+			return errNotWatched
+		}
+		atomic.StoreInt32(&w.isrec, 1)
+		return nil
+	case [2]bool{true, false}:
+		w, ok := fse.watches[oldpath]
+		if !ok {
+			return errNotWatched
+		}
+		if !atomic.CompareAndSwapUint32(&w.events, uint32(oldevent), uint32(newevent)) {
+			return errors.New("invalid event state diff")
+		}
+		atomic.StoreInt32(&w.isrec, 1)
+		return nil
+	default:
+		// TODO(rjeczalik): rewatch newpath only if exists?
+		// TODO(rjeczalik): migrate w.prev to new watch?
+		if _, ok := fse.watches[newpath]; ok {
+			return errAlreadyWatched
+		}
+		if err := fse.Unwatch(oldpath); err != nil {
+			return err
+		}
+		// TODO(rjeczalik): revert unwatch if watch fails?
+		return fse.watch(newpath, newevent, 1)
+	}
+}
+
+// Close unwatches all watch-points.
+func (fse *fsevents) Close() error {
+	for _, w := range fse.watches {
+		w.Stop()
+	}
+	fse.watches = nil
+	return nil
+}