1 // Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
2 // Use of this source code is governed by the MIT license that can be
3 // found in the LICENSE file.
10 errAlreadyWatched = errors.New("path is already watched")
11 errNotWatched = errors.New("path is not being watched")
12 errInvalidEventSet = errors.New("invalid event set provided")
15 // Watcher is a intermediate interface for wrapping inotify, ReadDirChangesW,
16 // FSEvents, kqueue and poller implementations.
18 // The watcher implementation is expected to do its own mapping between paths and
19 // create watchers if underlying event notification does not support it. For
20 // the ease of implementation it is guaranteed that paths provided via Watch and
21 // Unwatch methods are absolute and clean.
22 type watcher interface {
23 // Watch requests a watcher creation for the given path and given event set.
24 Watch(path string, event Event) error
26 // Unwatch requests a watcher deletion for the given path and given event set.
27 Unwatch(path string) error
29 // Rewatch provides a functionality for modifying existing watch-points, like
30 // expanding its event set.
32 // Rewatch modifies existing watch-point under for the given path. It passes
33 // the existing event set currently registered for the given path, and the
34 // new, requested event set.
36 // It is guaranteed that Tree will not pass to Rewatch zero value for any
37 // of its arguments. If old == new and watcher can be upgraded to
38 // recursiveWatcher interface, a watch for the corresponding path is expected
39 // to be changed from recursive to the non-recursive one.
40 Rewatch(path string, old, new Event) error
42 // Close unwatches all paths that are registered. When Close returns, it
43 // is expected it will report no more events.
47 // RecursiveWatcher is an interface for a Watcher for those OS, which do support
48 // recursive watching over directories.
49 type recursiveWatcher interface {
50 RecursiveWatch(path string, event Event) error
52 // RecursiveUnwatch removes a recursive watch-point given by the path. For
53 // native recursive implementation there is no difference in functionality
54 // between Unwatch and RecursiveUnwatch, however for those platforms, that
55 // requires emulation for recursive watch-points, the implementation differs.
56 RecursiveUnwatch(path string) error
58 // RecursiveRewatcher provides a functionality for modifying and/or relocating
59 // existing recursive watch-points.
61 // To relocate a watch-point means to unwatch oldpath and set a watch-point on
64 // To modify a watch-point means either to expand or shrink its event set.
66 // Tree can want to either relocate, modify or relocate and modify a watch-point
67 // via single RecursiveRewatch call.
69 // If oldpath == newpath, the watch-point is expected to change its event set value
70 // from oldevent to newevent.
72 // If oldevent == newevent, the watch-point is expected to relocate from oldpath
75 // If oldpath != newpath and oldevent != newevent, the watch-point is expected
76 // to relocate from oldpath to the newpath first and then change its event set
77 // value from oldevent to the newevent. In other words the end result must be
78 // a watch-point set on newpath with newevent value of its event set.
80 // It is guaranteed that Tree will not pass to RecurisveRewatcha zero value
81 // for any of its arguments. If oldpath == newpath and oldevent == newevent,
82 // a watch for the corresponding path is expected to be changed for
83 // non-recursive to the recursive one.
84 RecursiveRewatch(oldpath, newpath string, oldevent, newevent Event) error