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// Copyright (C) 2016 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
//go:build !(solaris && !cgo) && !(darwin && !cgo) && !(darwin && kqueue) && !(android && amd64)
// +build !solaris cgo
// +build !darwin cgo
// +build !darwin !kqueue
// +build !android !amd64
package fs
import (
"context"
"errors"
"unicode/utf8"
"github.com/syncthing/notify"
)
// Notify does not block on sending to channel, so the channel must be buffered.
// The actual number is magic.
// Not meant to be changed, but must be changeable for tests
var backendBuffer = 500
func (f *BasicFilesystem) Watch(name string, ignore Matcher, ctx context.Context, ignorePerms bool) (<-chan Event, <-chan error, error) {
watchPath, roots, err := f.watchPaths(name)
if err != nil {
return nil, nil, err
}
outChan := make(chan Event)
backendChan := make(chan notify.EventInfo, backendBuffer)
eventMask := subEventMask
if !ignorePerms {
eventMask |= permEventMask
}
absShouldIgnore := func(absPath string) bool {
if !utf8.ValidString(absPath) {
return true
}
rel, err := f.unrootedChecked(absPath, roots)
if err != nil {
return true
}
return ignore.Match(rel).CanSkipDir()
}
err = notify.WatchWithFilter(watchPath, backendChan, absShouldIgnore, eventMask)
if err != nil {
notify.Stop(backendChan)
if reachedMaxUserWatches(err) {
err = errors.New("failed to setup inotify handler. Please increase inotify limits, see https://docs.syncthing.net/users/faq.html#inotify-limits")
}
return nil, nil, err
}
errChan := make(chan error)
go f.watchLoop(ctx, name, roots, backendChan, outChan, errChan, ignore)
return outChan, errChan, nil
}
func (f *BasicFilesystem) watchLoop(ctx context.Context, name string, roots []string, backendChan chan notify.EventInfo, outChan chan<- Event, errChan chan<- error, ignore Matcher) {
for {
// Detect channel overflow
if len(backendChan) == backendBuffer {
outer:
for {
select {
case <-backendChan:
default:
break outer
}
}
// When next scheduling a scan, do it on the entire folder as events have been lost.
outChan <- Event{Name: name, Type: NonRemove}
l.Debugln(f.Type(), f.URI(), "Watch: Event overflow, send \".\"")
}
select {
case ev := <-backendChan:
evPath := ev.Path()
if !utf8.ValidString(evPath) {
l.Debugln(f.Type(), f.URI(), "Watch: Ignoring invalid UTF-8")
continue
}
relPath, err := f.unrootedChecked(evPath, roots)
if err != nil {
select {
case errChan <- err:
l.Debugln(f.Type(), f.URI(), "Watch: Sending error", err)
case <-ctx.Done():
}
notify.Stop(backendChan)
l.Debugln(f.Type(), f.URI(), "Watch: Stopped due to", err)
return
}
if ignore.Match(relPath).IsIgnored() {
l.Debugln(f.Type(), f.URI(), "Watch: Ignoring", relPath)
continue
}
evType := f.eventType(ev.Event())
select {
case outChan <- Event{Name: relPath, Type: evType}:
l.Debugln(f.Type(), f.URI(), "Watch: Sending", relPath, evType)
case <-ctx.Done():
notify.Stop(backendChan)
l.Debugln(f.Type(), f.URI(), "Watch: Stopped")
return
}
case <-ctx.Done():
notify.Stop(backendChan)
l.Debugln(f.Type(), f.URI(), "Watch: Stopped")
return
}
}
}
func (*BasicFilesystem) eventType(notifyType notify.Event) EventType {
if notifyType&rmEventMask != 0 {
return Remove
}
return NonRemove
}
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