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84 lines
3.9 KiB
Go
84 lines
3.9 KiB
Go
// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
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// Use of this source code is governed by the MIT license that can be
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// found in the LICENSE file.
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// BUG(rjeczalik): Notify does not collect watchpoints, when underlying watches
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// were removed by their os-specific watcher implementations. Instead users are
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// advised to listen on persistent paths to have guarantee they receive events
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// for the whole lifetime of their applications (to discuss see #69).
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// BUG(ppknap): Linux (inotify) does not support watcher behavior masks like
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// InOneshot, InOnlydir etc. Instead users are advised to perform the filtering
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// themselves (to discuss see #71).
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// BUG(ppknap): Notify was not tested for short path name support under Windows
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// (ReadDirectoryChangesW).
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// BUG(ppknap): Windows (ReadDirectoryChangesW) cannot recognize which notification
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// triggers FileActionModified event. (to discuss see #75).
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package notify
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var defaultTree = newTree()
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// Watch sets up a watchpoint on path listening for events given by the events
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// argument.
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//
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// File or directory given by the path must exist, otherwise Watch will fail
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// with non-nil error. Notify resolves, for its internal purpose, any symlinks
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// the provided path may contain, so it may fail if the symlinks form a cycle.
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// It does so, since not all watcher implementations treat passed paths as-is.
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// E.g. FSEvents reports a real path for every event, setting a watchpoint
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// on /tmp will report events with paths rooted at /private/tmp etc.
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//
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// The c almost always is a buffered channel. Watch will not block sending to c
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// - the caller must ensure that c has sufficient buffer space to keep up with
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// the expected event rate.
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//
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// It is allowed to pass the same channel multiple times with different event
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// list or different paths. Calling Watch with different event lists for a single
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// watchpoint expands its event set. The only way to shrink it, is to call
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// Stop on its channel.
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//
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// Calling Watch with empty event list does expand nor shrink watchpoint's event
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// set. If c is the first channel to listen for events on the given path, Watch
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// will seamlessly create a watch on the filesystem.
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//
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// Notify dispatches copies of single filesystem event to all channels registered
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// for each path. If a single filesystem event contains multiple coalesced events,
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// each of them is dispatched separately. E.g. the following filesystem change:
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//
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// ~ $ echo Hello > Notify.txt
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//
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// dispatches two events - notify.Create and notify.Write. However, it may depend
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// on the underlying watcher implementation whether OS reports both of them.
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//
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// Windows and recursive watches
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//
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// If a directory which path was used to create recursive watch under Windows
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// gets deleted, the OS will not report such event. It is advised to keep in
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// mind this limitation while setting recursive watchpoints for your application,
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// e.g. use persistent paths like %userprofile% or watch additionally parent
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// directory of a recursive watchpoint in order to receive delete events for it.
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func Watch(path string, c chan<- EventInfo, events ...Event) error {
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return defaultTree.Watch(path, c, nil, events...)
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}
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// This function works the same way as Watch. In addition it does not watch
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// files or directories based on the return value of the argument function
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// doNotWatch. Given a path as argument doNotWatch should return true if the
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// file or directory should not be watched.
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func WatchWithFilter(path string, c chan<- EventInfo,
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doNotWatch func(string) bool, events ...Event) error {
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return defaultTree.Watch(path, c, doNotWatch, events...)
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}
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// Stop removes all watchpoints registered for c. All underlying watches are
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// also removed, for which c was the last channel listening for events.
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//
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// Stop does not close c. When Stop returns, it is guaranteed that c will
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// receive no more signals.
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func Stop(c chan<- EventInfo) {
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defaultTree.Stop(c)
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}
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