func (fw *InotifyFileWatcher) BlockUntilExists(t tomb.Tomb) error {
w, err := fsnotify.NewWatcher()
if err != nil {
return err
}
defer w.Close()
dirname := filepath.Dir(fw.Filename)
// Watch for new files to be created in the parent directory.
err = w.WatchFlags(dirname, fsnotify.FSN_CREATE)
if err != nil {
return err
}
defer w.RemoveWatch(filepath.Dir(fw.Filename))
// Do a real check now as the file might have been created before
// calling `WatchFlags` above.
if _, err = os.Stat(fw.Filename); !os.IsNotExist(err) {
// file exists, or stat returned an error.
return err
}
for {
select {
case evt := <-w.Event:
if evt.Name == fw.Filename {
return nil
}
case <-t.Dying():
return tomb.ErrDying
}
}
panic("unreachable")
}
func (s *fslockSuite) TestTomb(c *gc.C) {
const timeToDie = 200 * time.Millisecond
die := tomb.Tomb{}
dir := c.MkDir()
lock, err := fslock.NewLock(dir, "testing", s.lockConfig)
c.Assert(err, gc.IsNil)
// Just use one lock, and try to lock it twice.
err = lock.Lock("very busy")
c.Assert(err, gc.IsNil)
checkTomb := func() error {
select {
case <-die.Dying():
return tomb.ErrDying
default:
// no-op to fall through to return.
}
return nil
}
go func() {
time.Sleep(timeToDie)
die.Killf("time to die")
}()
err = lock.LockWithFunc("won't happen", checkTomb)
c.Assert(errors.Cause(err), gc.Equals, tomb.ErrDying)
msg, err := lock.Message()
c.Assert(err, gc.IsNil)
c.Assert(msg, gc.Equals, "very busy")
}
func (fw *InotifyFileWatcher) ChangeEvents(t tomb.Tomb, fi os.FileInfo) chan bool {
w, err := fsnotify.NewWatcher()
if err != nil {
panic(err)
}
err = w.Watch(fw.Filename)
if err != nil {
panic(err)
}
ch := make(chan bool)
fw.Size = fi.Size()
go func() {
defer w.Close()
defer w.RemoveWatch(fw.Filename)
defer close(ch)
for {
prevSize := fw.Size
var evt *fsnotify.FileEvent
select {
case evt = <-w.Event:
case <-t.Dying():
return
}
switch {
case evt.IsDelete():
fallthrough
case evt.IsRename():
return
case evt.IsModify():
fi, err := os.Stat(fw.Filename)
if err != nil {
// XXX: no panic here
panic(err)
}
fw.Size = fi.Size()
if prevSize > 0 && prevSize > fw.Size {
return
}
// send only if channel is empty.
select {
case ch <- true:
default:
}
}
}
}()
return ch
}
func (fw *InotifyFileWatcher) ChangeEvents(t tomb.Tomb, fi os.FileInfo) *FileChanges {
changes := NewFileChanges()
w, err := fsnotify.NewWatcher()
if err != nil {
panic(err)
}
err = w.Watch(fw.Filename)
if err != nil {
panic(err)
}
fw.Size = fi.Size()
go func() {
defer w.Close()
defer w.RemoveWatch(fw.Filename)
defer changes.Close()
for {
prevSize := fw.Size
var evt *fsnotify.FileEvent
select {
case evt = <-w.Event:
case <-t.Dying():
return
}
switch {
case evt.IsDelete():
fallthrough
case evt.IsRename():
changes.NotifyDeleted()
return
case evt.IsModify():
fi, err := os.Stat(fw.Filename)
if err != nil {
// XXX: no panic here
panic(err)
}
fw.Size = fi.Size()
if prevSize > 0 && prevSize > fw.Size {
changes.NotifyTruncated()
} else {
changes.NotifyModified()
}
prevSize = fw.Size
}
}
}()
return changes
}
func (fw *PollingFileWatcher) ChangeEvents(t *tomb.Tomb, origFi os.FileInfo) *FileChanges {
changes := NewFileChanges()
var prevModTime time.Time
// XXX: use tomb.Tomb to cleanly manage these goroutines. replace
// the fatal (below) with tomb's Kill.
fw.Size = origFi.Size()
go func() {
defer changes.Close()
prevSize := fw.Size
for {
select {
case <-t.Dying():
return
default:
}
time.Sleep(POLL_DURATION)
fi, err := os.Stat(fw.Filename)
if err != nil {
if os.IsNotExist(err) {
// File does not exist (has been deleted).
changes.NotifyDeleted()
return
}
// XXX: report this error back to the user
util.Fatal("Failed to stat file %v: %v", fw.Filename, err)
}
// File got moved/renamed?
if !os.SameFile(origFi, fi) {
changes.NotifyDeleted()
return
}
// File got truncated?
fw.Size = fi.Size()
if prevSize > 0 && prevSize > fw.Size {
changes.NotifyTruncated()
prevSize = fw.Size
continue
}
prevSize = fw.Size
// File was appended to (changed)?
modTime := fi.ModTime()
if modTime != prevModTime {
prevModTime = modTime
changes.NotifyModified()
}
}
}()
return changes
}
// delayedTomb returns a tomb that starts dying a given duration
// after t starts dying.
func delayedTomb(t *tomb.Tomb, d time.Duration) *tomb.Tomb {
var delayed tomb.Tomb
go func() {
select {
case <-t.Dying():
time.Sleep(d)
delayed.Kill(nil)
case <-delayed.Dying():
return
}
}()
return &delayed
}
func (fw *PollingFileWatcher) BlockUntilExists(t tomb.Tomb) error {
for {
if _, err := os.Stat(fw.Filename); err == nil {
return nil
} else if !os.IsNotExist(err) {
return err
}
select {
case <-time.After(POLL_DURATION):
continue
case <-t.Dying():
return tomb.ErrDying
}
}
panic("unreachable")
}
func testState(t *testing.T, tb *tomb.Tomb, wantDying, wantDead bool, wantErr error) {
select {
case <-tb.Dying():
if !wantDying {
t.Error("<-Dying: should block")
}
default:
if wantDying {
t.Error("<-Dying: should not block")
}
}
seemsDead := false
select {
case <-tb.Dead():
if !wantDead {
t.Error("<-Dead: should block")
}
seemsDead = true
default:
if wantDead {
t.Error("<-Dead: should not block")
}
}
if err := tb.Err(); err != wantErr {
t.Errorf("Err: want %#v, got %#v", wantErr, err)
}
if wantDead && seemsDead {
waitErr := tb.Wait()
switch {
case waitErr == tomb.ErrStillAlive:
t.Errorf("Wait should not return ErrStillAlive")
case !reflect.DeepEqual(waitErr, wantErr):
t.Errorf("Wait: want %#v, got %#v", wantErr, waitErr)
}
}
}
// copyEvents copies channel events from "in" to "out", coalescing.
func copyEvents(out chan<- struct{}, in <-chan struct{}, tomb *tomb.Tomb) {
var outC chan<- struct{}
for {
select {
case <-tomb.Dying():
return
case _, ok := <-in:
if !ok {
return
}
outC = out
case outC <- struct{}{}:
outC = nil
}
}
}
func (fw *PollingFileWatcher) ChangeEvents(t tomb.Tomb, origFi os.FileInfo) chan bool {
ch := make(chan bool)
stop := make(chan bool)
var once sync.Once
var prevModTime time.Time
// XXX: use tomb.Tomb to cleanly manage these goroutines. replace
// the panic (below) with tomb's Kill.
stopAndClose := func() {
go func() {
close(ch)
stop <- true
}()
}
fw.Size = origFi.Size()
go func() {
prevSize := fw.Size
for {
select {
case <-stop:
return
case <-t.Dying():
once.Do(stopAndClose)
continue
default:
}
time.Sleep(POLL_DURATION)
fi, err := os.Stat(fw.Filename)
if err != nil {
if os.IsNotExist(err) {
once.Do(stopAndClose)
continue
}
/// XXX: do not panic here.
panic(err)
}
// File got moved/rename within POLL_DURATION?
if !os.SameFile(origFi, fi) {
once.Do(stopAndClose)
continue
}
// Was the file truncated?
fw.Size = fi.Size()
if prevSize > 0 && prevSize > fw.Size {
once.Do(stopAndClose)
continue
}
// If the file was changed since last check, notify.
modTime := fi.ModTime()
if modTime != prevModTime {
prevModTime = modTime
select {
case ch <- true:
default:
}
}
}
}()
return ch
}
func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, fi os.FileInfo) *FileChanges {
changes := NewFileChanges()
w, err := inotifyTracker.NewWatcher()
if err != nil {
util.Fatal("Error creating fsnotify watcher: %v", err)
}
err = w.Watch(fw.Filename)
if err != nil {
util.Fatal("Error watching %v: %v", fw.Filename, err)
}
fw.Size = fi.Size()
go func() {
defer inotifyTracker.CloseWatcher(w)
defer changes.Close()
for {
prevSize := fw.Size
var evt *fsnotify.FileEvent
var ok bool
select {
case evt, ok = <-w.Event:
if !ok {
return
}
case <-t.Dying():
return
}
switch {
case evt.IsDelete():
fallthrough
case evt.IsRename():
changes.NotifyDeleted()
return
case evt.IsModify():
fi, err := os.Stat(fw.Filename)
if err != nil {
if os.IsNotExist(err) {
changes.NotifyDeleted()
return
}
// XXX: report this error back to the user
util.Fatal("Failed to stat file %v: %v", fw.Filename, err)
}
fw.Size = fi.Size()
if prevSize > 0 && prevSize > fw.Size {
changes.NotifyTruncated()
} else {
changes.NotifyModified()
}
prevSize = fw.Size
}
}
}()
return changes
}