2016-04-26 16:01:46 +02:00
|
|
|
// Copyright (C) 2014 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,
|
2017-02-09 07:52:18 +01:00
|
|
|
// You can obtain one at https://mozilla.org/MPL/2.0/.
|
2016-04-26 16:01:46 +02:00
|
|
|
|
|
|
|
package model
|
|
|
|
|
2017-04-26 02:15:23 +02:00
|
|
|
import (
|
|
|
|
"context"
|
2018-02-04 22:46:24 +01:00
|
|
|
"errors"
|
2018-05-23 09:23:21 +02:00
|
|
|
"fmt"
|
2018-05-21 08:45:05 +02:00
|
|
|
"math/rand"
|
2018-10-05 10:26:25 +02:00
|
|
|
"sync/atomic"
|
2017-04-26 02:15:23 +02:00
|
|
|
"time"
|
2017-08-25 21:47:01 +02:00
|
|
|
|
|
|
|
"github.com/syncthing/syncthing/lib/config"
|
2018-05-21 08:56:24 +02:00
|
|
|
"github.com/syncthing/syncthing/lib/db"
|
2018-06-11 15:47:54 +02:00
|
|
|
"github.com/syncthing/syncthing/lib/events"
|
2018-02-04 22:46:24 +01:00
|
|
|
"github.com/syncthing/syncthing/lib/ignore"
|
2018-02-25 09:39:00 +01:00
|
|
|
"github.com/syncthing/syncthing/lib/protocol"
|
2018-02-04 22:46:24 +01:00
|
|
|
"github.com/syncthing/syncthing/lib/sync"
|
2017-10-20 16:52:55 +02:00
|
|
|
"github.com/syncthing/syncthing/lib/watchaggregator"
|
2017-04-26 02:15:23 +02:00
|
|
|
)
|
2016-04-26 16:01:46 +02:00
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
var errWatchNotStarted = errors.New("not started")
|
2018-02-04 22:46:24 +01:00
|
|
|
|
2016-04-26 16:01:46 +02:00
|
|
|
type folder struct {
|
|
|
|
stateTracker
|
2017-08-25 21:47:01 +02:00
|
|
|
config.FolderConfiguration
|
2018-07-12 10:15:57 +02:00
|
|
|
localFlags uint32
|
2017-04-01 11:58:06 +02:00
|
|
|
|
2018-02-25 09:39:00 +01:00
|
|
|
model *Model
|
|
|
|
shortID protocol.ShortID
|
|
|
|
ctx context.Context
|
|
|
|
cancel context.CancelFunc
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
scanInterval time.Duration
|
|
|
|
scanTimer *time.Timer
|
|
|
|
scanNow chan rescanRequest
|
|
|
|
scanDelay chan time.Duration
|
2017-04-20 02:20:34 +02:00
|
|
|
initialScanFinished chan struct{}
|
2018-06-10 13:24:59 +02:00
|
|
|
stopped chan struct{}
|
2018-02-25 09:39:00 +01:00
|
|
|
|
|
|
|
pullScheduled chan struct{}
|
|
|
|
|
|
|
|
watchCancel context.CancelFunc
|
|
|
|
watchChan chan []string
|
|
|
|
restartWatchChan chan struct{}
|
|
|
|
watchErr error
|
|
|
|
watchErrMut sync.Mutex
|
2018-05-11 10:45:13 +02:00
|
|
|
|
|
|
|
puller puller
|
|
|
|
}
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
type rescanRequest struct {
|
|
|
|
subdirs []string
|
|
|
|
err chan error
|
|
|
|
}
|
|
|
|
|
2018-05-11 10:45:13 +02:00
|
|
|
type puller interface {
|
|
|
|
pull() bool // true when successfull and should not be retried
|
2016-04-26 16:01:46 +02:00
|
|
|
}
|
|
|
|
|
2017-08-25 21:47:01 +02:00
|
|
|
func newFolder(model *Model, cfg config.FolderConfiguration) folder {
|
|
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
|
|
|
|
|
|
return folder{
|
|
|
|
stateTracker: newStateTracker(cfg.ID),
|
|
|
|
FolderConfiguration: cfg,
|
|
|
|
|
2018-02-25 09:39:00 +01:00
|
|
|
model: model,
|
|
|
|
shortID: model.shortID,
|
|
|
|
ctx: ctx,
|
|
|
|
cancel: cancel,
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
scanInterval: time.Duration(cfg.RescanIntervalS) * time.Second,
|
|
|
|
scanTimer: time.NewTimer(time.Millisecond), // The first scan should be done immediately.
|
|
|
|
scanNow: make(chan rescanRequest),
|
|
|
|
scanDelay: make(chan time.Duration),
|
2017-08-25 21:47:01 +02:00
|
|
|
initialScanFinished: make(chan struct{}),
|
2018-06-11 15:47:54 +02:00
|
|
|
stopped: make(chan struct{}),
|
2018-02-25 09:39:00 +01:00
|
|
|
|
|
|
|
pullScheduled: make(chan struct{}, 1), // This needs to be 1-buffered so that we queue a pull if we're busy when it comes.
|
|
|
|
|
2018-06-11 15:47:54 +02:00
|
|
|
watchCancel: func() {},
|
|
|
|
restartWatchChan: make(chan struct{}, 1),
|
|
|
|
watchErrMut: sync.NewMutex(),
|
2017-08-25 21:47:01 +02:00
|
|
|
}
|
2016-04-26 16:01:46 +02:00
|
|
|
}
|
|
|
|
|
2018-05-11 10:45:13 +02:00
|
|
|
func (f *folder) Serve() {
|
2018-10-05 10:26:25 +02:00
|
|
|
atomic.AddInt32(&f.model.foldersRunning, 1)
|
|
|
|
defer atomic.AddInt32(&f.model.foldersRunning, -1)
|
|
|
|
|
2018-05-11 10:45:13 +02:00
|
|
|
l.Debugln(f, "starting")
|
|
|
|
defer l.Debugln(f, "exiting")
|
|
|
|
|
|
|
|
defer func() {
|
2018-05-21 08:45:05 +02:00
|
|
|
f.scanTimer.Stop()
|
2018-05-11 10:45:13 +02:00
|
|
|
f.setState(FolderIdle)
|
2018-06-10 13:24:59 +02:00
|
|
|
close(f.stopped)
|
2018-05-11 10:45:13 +02:00
|
|
|
}()
|
|
|
|
|
|
|
|
pause := f.basePause()
|
|
|
|
pullFailTimer := time.NewTimer(0)
|
|
|
|
<-pullFailTimer.C
|
|
|
|
|
|
|
|
if f.FSWatcherEnabled && f.CheckHealth() == nil {
|
|
|
|
f.startWatch()
|
|
|
|
}
|
|
|
|
|
|
|
|
initialCompleted := f.initialScanFinished
|
|
|
|
|
|
|
|
for {
|
|
|
|
select {
|
|
|
|
case <-f.ctx.Done():
|
|
|
|
return
|
|
|
|
|
|
|
|
case <-f.pullScheduled:
|
|
|
|
pullFailTimer.Stop()
|
|
|
|
select {
|
|
|
|
case <-pullFailTimer.C:
|
|
|
|
default:
|
|
|
|
}
|
|
|
|
|
|
|
|
if !f.puller.pull() {
|
|
|
|
// Pulling failed, try again later.
|
|
|
|
pullFailTimer.Reset(pause)
|
|
|
|
}
|
|
|
|
|
|
|
|
case <-pullFailTimer.C:
|
|
|
|
if f.puller.pull() {
|
|
|
|
// We're good. Don't schedule another fail pull and reset
|
|
|
|
// the pause interval.
|
|
|
|
pause = f.basePause()
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
|
|
|
|
// Pulling failed, try again later.
|
|
|
|
l.Infof("Folder %v isn't making sync progress - retrying in %v.", f.Description(), pause)
|
|
|
|
pullFailTimer.Reset(pause)
|
|
|
|
// Back off from retrying to pull with an upper limit.
|
|
|
|
if pause < 60*f.basePause() {
|
|
|
|
pause *= 2
|
|
|
|
}
|
|
|
|
|
|
|
|
case <-initialCompleted:
|
|
|
|
// Initial scan has completed, we should do a pull
|
|
|
|
initialCompleted = nil // never hit this case again
|
|
|
|
if !f.puller.pull() {
|
|
|
|
// Pulling failed, try again later.
|
|
|
|
pullFailTimer.Reset(pause)
|
|
|
|
}
|
|
|
|
|
|
|
|
// The reason for running the scanner from within the puller is that
|
|
|
|
// this is the easiest way to make sure we are not doing both at the
|
|
|
|
// same time.
|
2018-05-21 08:45:05 +02:00
|
|
|
case <-f.scanTimer.C:
|
2018-05-11 10:45:13 +02:00
|
|
|
l.Debugln(f, "Scanning subdirectories")
|
|
|
|
f.scanTimerFired()
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
case req := <-f.scanNow:
|
2018-05-11 10:45:13 +02:00
|
|
|
req.err <- f.scanSubdirs(req.subdirs)
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
case next := <-f.scanDelay:
|
|
|
|
f.scanTimer.Reset(next)
|
2018-05-11 10:45:13 +02:00
|
|
|
|
|
|
|
case fsEvents := <-f.watchChan:
|
|
|
|
l.Debugln(f, "filesystem notification rescan")
|
|
|
|
f.scanSubdirs(fsEvents)
|
|
|
|
|
|
|
|
case <-f.restartWatchChan:
|
|
|
|
f.restartWatch()
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2017-10-24 09:58:55 +02:00
|
|
|
func (f *folder) BringToFront(string) {}
|
|
|
|
|
2018-05-21 08:56:24 +02:00
|
|
|
func (f *folder) Override(fs *db.FileSet, updateFn func([]protocol.FileInfo)) {}
|
|
|
|
|
2018-07-12 10:15:57 +02:00
|
|
|
func (f *folder) Revert(fs *db.FileSet, updateFn func([]protocol.FileInfo)) {}
|
|
|
|
|
2016-04-26 16:01:46 +02:00
|
|
|
func (f *folder) DelayScan(next time.Duration) {
|
2018-05-21 08:45:05 +02:00
|
|
|
f.Delay(next)
|
2016-04-26 16:01:46 +02:00
|
|
|
}
|
|
|
|
|
2017-10-24 09:58:55 +02:00
|
|
|
func (f *folder) IgnoresUpdated() {
|
|
|
|
if f.FSWatcherEnabled {
|
|
|
|
f.scheduleWatchRestart()
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2018-02-25 09:39:00 +01:00
|
|
|
func (f *folder) SchedulePull() {
|
|
|
|
select {
|
|
|
|
case f.pullScheduled <- struct{}{}:
|
|
|
|
default:
|
|
|
|
// We might be busy doing a pull and thus not reading from this
|
|
|
|
// channel. The channel is 1-buffered, so one notification will be
|
|
|
|
// queued to ensure we recheck after the pull, but beyond that we must
|
|
|
|
// make sure to not block index receiving.
|
|
|
|
}
|
|
|
|
}
|
2017-11-07 07:59:35 +01:00
|
|
|
|
2017-10-24 09:58:55 +02:00
|
|
|
func (f *folder) Jobs() ([]string, []string) {
|
|
|
|
return nil, nil
|
|
|
|
}
|
|
|
|
|
2016-04-26 16:01:46 +02:00
|
|
|
func (f *folder) Scan(subdirs []string) error {
|
2017-04-20 02:20:34 +02:00
|
|
|
<-f.initialScanFinished
|
2018-05-21 08:45:05 +02:00
|
|
|
req := rescanRequest{
|
|
|
|
subdirs: subdirs,
|
|
|
|
err: make(chan error),
|
|
|
|
}
|
2018-07-04 09:07:33 +02:00
|
|
|
|
|
|
|
select {
|
|
|
|
case f.scanNow <- req:
|
|
|
|
return <-req.err
|
|
|
|
case <-f.ctx.Done():
|
|
|
|
return f.ctx.Err()
|
|
|
|
}
|
2018-05-21 08:45:05 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
func (f *folder) Reschedule() {
|
|
|
|
if f.scanInterval == 0 {
|
|
|
|
return
|
|
|
|
}
|
|
|
|
// Sleep a random time between 3/4 and 5/4 of the configured interval.
|
|
|
|
sleepNanos := (f.scanInterval.Nanoseconds()*3 + rand.Int63n(2*f.scanInterval.Nanoseconds())) / 4
|
|
|
|
interval := time.Duration(sleepNanos) * time.Nanosecond
|
|
|
|
l.Debugln(f, "next rescan in", interval)
|
|
|
|
f.scanTimer.Reset(interval)
|
|
|
|
}
|
|
|
|
|
|
|
|
func (f *folder) Delay(next time.Duration) {
|
|
|
|
f.scanDelay <- next
|
2016-04-26 16:01:46 +02:00
|
|
|
}
|
2017-04-26 02:15:23 +02:00
|
|
|
|
2016-04-26 16:01:46 +02:00
|
|
|
func (f *folder) Stop() {
|
2017-04-26 02:15:23 +02:00
|
|
|
f.cancel()
|
2018-06-10 13:24:59 +02:00
|
|
|
<-f.stopped
|
2016-04-26 16:01:46 +02:00
|
|
|
}
|
|
|
|
|
2017-10-24 09:58:55 +02:00
|
|
|
// CheckHealth checks the folder for common errors, updates the folder state
|
|
|
|
// and returns the current folder error, or nil if the folder is healthy.
|
|
|
|
func (f *folder) CheckHealth() error {
|
|
|
|
err := f.getHealthError()
|
|
|
|
f.setError(err)
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
func (f *folder) getHealthError() error {
|
|
|
|
// Check for folder errors, with the most serious and specific first and
|
|
|
|
// generic ones like out of space on the home disk later.
|
|
|
|
|
|
|
|
if err := f.CheckPath(); err != nil {
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
|
|
|
|
if err := f.model.cfg.CheckHomeFreeSpace(); err != nil {
|
|
|
|
return err
|
|
|
|
}
|
2016-04-26 16:01:46 +02:00
|
|
|
|
2017-10-12 08:16:46 +02:00
|
|
|
return nil
|
|
|
|
}
|
|
|
|
|
2017-04-20 02:20:34 +02:00
|
|
|
func (f *folder) scanSubdirs(subDirs []string) error {
|
2018-07-12 10:15:57 +02:00
|
|
|
if err := f.model.internalScanFolderSubdirs(f.ctx, f.folderID, subDirs, f.localFlags); err != nil {
|
2016-04-26 16:01:46 +02:00
|
|
|
// Potentially sets the error twice, once in the scanner just
|
|
|
|
// by doing a check, and once here, if the error returned is
|
2017-10-24 09:58:55 +02:00
|
|
|
// the same one as returned by CheckHealth, though
|
2016-04-26 16:01:46 +02:00
|
|
|
// duplicate set is handled by setError.
|
|
|
|
f.setError(err)
|
|
|
|
return err
|
|
|
|
}
|
|
|
|
return nil
|
|
|
|
}
|
2017-09-07 08:17:47 +02:00
|
|
|
|
|
|
|
func (f *folder) scanTimerFired() {
|
|
|
|
err := f.scanSubdirs(nil)
|
|
|
|
|
|
|
|
select {
|
|
|
|
case <-f.initialScanFinished:
|
|
|
|
default:
|
|
|
|
status := "Completed"
|
|
|
|
if err != nil {
|
|
|
|
status = "Failed"
|
|
|
|
}
|
|
|
|
l.Infoln(status, "initial scan of", f.Type.String(), "folder", f.Description())
|
|
|
|
close(f.initialScanFinished)
|
|
|
|
}
|
|
|
|
|
2018-05-21 08:45:05 +02:00
|
|
|
f.Reschedule()
|
2017-09-07 08:17:47 +02:00
|
|
|
}
|
2017-10-20 16:52:55 +02:00
|
|
|
|
2018-02-04 22:46:24 +01:00
|
|
|
func (f *folder) WatchError() error {
|
|
|
|
f.watchErrMut.Lock()
|
|
|
|
defer f.watchErrMut.Unlock()
|
|
|
|
return f.watchErr
|
2017-10-20 16:52:55 +02:00
|
|
|
}
|
|
|
|
|
2018-02-04 22:46:24 +01:00
|
|
|
// stopWatch immediately aborts watching and may be called asynchronously
|
|
|
|
func (f *folder) stopWatch() {
|
2017-10-20 16:52:55 +02:00
|
|
|
f.watchCancel()
|
2018-02-04 22:46:24 +01:00
|
|
|
f.watchErrMut.Lock()
|
2018-06-11 15:47:54 +02:00
|
|
|
prevErr := f.watchErr
|
2018-02-04 22:46:24 +01:00
|
|
|
f.watchErr = errWatchNotStarted
|
|
|
|
f.watchErrMut.Unlock()
|
2018-06-11 15:47:54 +02:00
|
|
|
if prevErr != errWatchNotStarted {
|
|
|
|
data := map[string]interface{}{
|
|
|
|
"folder": f.ID,
|
|
|
|
"to": errWatchNotStarted.Error(),
|
|
|
|
}
|
|
|
|
if prevErr != nil {
|
|
|
|
data["from"] = prevErr.Error()
|
|
|
|
}
|
|
|
|
events.Default.Log(events.FolderWatchStateChanged, data)
|
|
|
|
}
|
2017-10-20 16:52:55 +02:00
|
|
|
}
|
|
|
|
|
2018-02-04 22:46:24 +01:00
|
|
|
// scheduleWatchRestart makes sure watching is restarted from the main for loop
|
|
|
|
// in a folder's Serve and thus may be called asynchronously (e.g. when ignores change).
|
2017-10-24 09:58:55 +02:00
|
|
|
func (f *folder) scheduleWatchRestart() {
|
2017-10-20 16:52:55 +02:00
|
|
|
select {
|
2017-10-24 09:58:55 +02:00
|
|
|
case f.restartWatchChan <- struct{}{}:
|
2017-10-20 16:52:55 +02:00
|
|
|
default:
|
|
|
|
// We might be busy doing a pull and thus not reading from this
|
|
|
|
// channel. The channel is 1-buffered, so one notification will be
|
|
|
|
// queued to ensure we recheck after the pull.
|
|
|
|
}
|
|
|
|
}
|
2017-10-24 09:58:55 +02:00
|
|
|
|
2018-02-04 22:46:24 +01:00
|
|
|
// restartWatch should only ever be called synchronously. If you want to use
|
|
|
|
// this asynchronously, you should probably use scheduleWatchRestart instead.
|
|
|
|
func (f *folder) restartWatch() {
|
|
|
|
f.stopWatch()
|
|
|
|
f.startWatch()
|
2018-06-11 15:47:54 +02:00
|
|
|
f.scanSubdirs(nil)
|
2018-02-04 22:46:24 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
// startWatch should only ever be called synchronously. If you want to use
|
|
|
|
// this asynchronously, you should probably use scheduleWatchRestart instead.
|
|
|
|
func (f *folder) startWatch() {
|
|
|
|
ctx, cancel := context.WithCancel(f.ctx)
|
|
|
|
f.model.fmut.RLock()
|
|
|
|
ignores := f.model.folderIgnores[f.folderID]
|
|
|
|
f.model.fmut.RUnlock()
|
|
|
|
f.watchChan = make(chan []string)
|
|
|
|
f.watchCancel = cancel
|
|
|
|
go f.startWatchAsync(ctx, ignores)
|
|
|
|
}
|
|
|
|
|
|
|
|
// startWatchAsync tries to start the filesystem watching and retries every minute on failure.
|
|
|
|
// It is a convenience function that should not be used except in startWatch.
|
|
|
|
func (f *folder) startWatchAsync(ctx context.Context, ignores *ignore.Matcher) {
|
|
|
|
timer := time.NewTimer(0)
|
|
|
|
for {
|
|
|
|
select {
|
|
|
|
case <-timer.C:
|
|
|
|
eventChan, err := f.Filesystem().Watch(".", ignores, ctx, f.IgnorePerms)
|
|
|
|
f.watchErrMut.Lock()
|
|
|
|
prevErr := f.watchErr
|
|
|
|
f.watchErr = err
|
|
|
|
f.watchErrMut.Unlock()
|
2018-06-11 15:47:54 +02:00
|
|
|
if err != prevErr {
|
|
|
|
data := map[string]interface{}{
|
|
|
|
"folder": f.ID,
|
|
|
|
}
|
|
|
|
if prevErr != nil {
|
|
|
|
data["from"] = prevErr.Error()
|
|
|
|
}
|
|
|
|
if err != nil {
|
|
|
|
data["to"] = err.Error()
|
|
|
|
}
|
|
|
|
events.Default.Log(events.FolderWatchStateChanged, data)
|
|
|
|
}
|
2018-02-04 22:46:24 +01:00
|
|
|
if err != nil {
|
|
|
|
if prevErr == errWatchNotStarted {
|
2018-06-11 15:47:54 +02:00
|
|
|
l.Infof("Error while trying to start filesystem watcher for folder %s, trying again in 1min: %v", f.Description(), err)
|
2018-02-04 22:46:24 +01:00
|
|
|
} else {
|
2018-06-11 15:47:54 +02:00
|
|
|
l.Debugf("Repeat error while trying to start filesystem watcher for folder %s, trying again in 1min: %v", f.Description(), err)
|
2018-02-04 22:46:24 +01:00
|
|
|
}
|
|
|
|
timer.Reset(time.Minute)
|
|
|
|
continue
|
|
|
|
}
|
|
|
|
watchaggregator.Aggregate(eventChan, f.watchChan, f.FolderConfiguration, f.model.cfg, ctx)
|
|
|
|
l.Debugln("Started filesystem watcher for folder", f.Description())
|
|
|
|
return
|
|
|
|
case <-ctx.Done():
|
|
|
|
return
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2017-10-24 09:58:55 +02:00
|
|
|
func (f *folder) setError(err error) {
|
|
|
|
_, _, oldErr := f.getState()
|
|
|
|
if (err != nil && oldErr != nil && oldErr.Error() == err.Error()) || (err == nil && oldErr == nil) {
|
|
|
|
return
|
|
|
|
}
|
|
|
|
|
|
|
|
if err != nil {
|
|
|
|
if oldErr == nil {
|
|
|
|
l.Warnf("Error on folder %s: %v", f.Description(), err)
|
|
|
|
} else {
|
|
|
|
l.Infof("Error on folder %s changed: %q -> %q", f.Description(), oldErr, err)
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
l.Infoln("Cleared error on folder", f.Description())
|
|
|
|
}
|
|
|
|
|
|
|
|
if f.FSWatcherEnabled {
|
|
|
|
if err != nil {
|
2018-02-04 22:46:24 +01:00
|
|
|
f.stopWatch()
|
2017-10-24 09:58:55 +02:00
|
|
|
} else {
|
|
|
|
f.scheduleWatchRestart()
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
f.stateTracker.setError(err)
|
|
|
|
}
|
2018-05-11 10:45:13 +02:00
|
|
|
|
|
|
|
func (f *folder) basePause() time.Duration {
|
|
|
|
if f.PullerPauseS == 0 {
|
|
|
|
return defaultPullerPause
|
|
|
|
}
|
|
|
|
return time.Duration(f.PullerPauseS) * time.Second
|
|
|
|
}
|
2018-05-23 09:23:21 +02:00
|
|
|
|
|
|
|
func (f *folder) String() string {
|
|
|
|
return fmt.Sprintf("%s/%s@%p", f.Type, f.folderID, f)
|
|
|
|
}
|