make watch.go its own package
for the purpose for upcoming changes to the watch functionality.
This commit is contained in:
Sridhar Ratnakumar
parent
b664e9fc9d
commit
0f67bc352f
7
tail.go
7
tail.go
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@ -10,6 +10,7 @@ import (
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"log"
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"os"
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"time"
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"github.com/ActiveState/tail/watch"
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)
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type Line struct {
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@ -34,7 +35,7 @@ type Tail struct {
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file *os.File
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reader *bufio.Reader
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watcher FileWatcher
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watcher watch.FileWatcher
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tomb.Tomb // provides: Done, Kill, Dying
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}
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@ -62,9 +63,9 @@ func TailFile(filename string, config Config) (*Tail, error) {
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Config: config}
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if t.Poll {
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t.watcher = NewPollingFileWatcher(filename)
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t.watcher = watch.NewPollingFileWatcher(filename)
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} else {
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t.watcher = NewInotifyFileWatcher(filename)
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t.watcher = watch.NewInotifyFileWatcher(filename)
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}
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if t.MustExist {
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11
tail_test.go
11
tail_test.go
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@ -11,6 +11,7 @@ import (
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"os"
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"testing"
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"time"
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"./watch"
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)
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func init() {
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@ -104,7 +105,7 @@ func _TestReOpen(_t *testing.T, poll bool) {
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if poll {
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// Give polling a chance to read the just-written lines (more;
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// data), before we recreate the file again below.
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<-time.After(POLL_DURATION)
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<-time.After(watch.POLL_DURATION)
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}
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// rename must trigger reopen
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@ -114,7 +115,7 @@ func _TestReOpen(_t *testing.T, poll bool) {
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if poll {
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// This time, wait a bit before creating the file to test
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// PollingFileWatcher's BlockUntilExists.
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<-time.After(POLL_DURATION)
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<-time.After(watch.POLL_DURATION)
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}
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t.CreateFile("test.txt", "endofworld")
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@ -159,7 +160,7 @@ func _TestReSeek(_t *testing.T, poll bool) {
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if poll {
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// Give polling a chance to read the just-written lines (more;
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// data), before we truncate the file again below.
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<-time.After(POLL_DURATION)
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<-time.After(watch.POLL_DURATION)
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}
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println("truncating..")
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t.TruncateFile("test.txt", "h311o\nw0r1d\nendofworld\n")
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@ -167,7 +168,7 @@ func _TestReSeek(_t *testing.T, poll bool) {
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if poll {
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// Give polling a chance to read the just-written lines (more;
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// data), before we recreate the file again below.
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<-time.After(POLL_DURATION)
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<-time.After(watch.POLL_DURATION)
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}
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// Delete after a reasonable delay, to give tail sufficient time
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@ -206,7 +207,7 @@ func NewTailTest(name string, t *testing.T) TailTest {
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}
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// Use a smaller poll duration for faster test runs.
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POLL_DURATION = 25 * time.Millisecond
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watch.POLL_DURATION = 25 * time.Millisecond
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return tt
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}
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215
watch.go
215
watch.go
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@ -1,215 +0,0 @@
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// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
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package tail
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import (
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"github.com/howeyc/fsnotify"
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"os"
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"path/filepath"
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"sync"
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"time"
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)
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// FileWatcher monitors file-level events.
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type FileWatcher interface {
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// BlockUntilExists blocks until the missing file comes into
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// existence. If the file already exists, returns immediately.
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BlockUntilExists() error
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// ChangeEvents returns a channel of events corresponding to the
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// times the file is ready to be read.
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ChangeEvents(os.FileInfo) chan bool
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}
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// InotifyFileWatcher uses inotify to monitor file changes.
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type InotifyFileWatcher struct {
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Filename string
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Size int64
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}
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func NewInotifyFileWatcher(filename string) *InotifyFileWatcher {
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fw := &InotifyFileWatcher{filename, 0}
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return fw
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}
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func (fw *InotifyFileWatcher) BlockUntilExists() error {
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w, err := fsnotify.NewWatcher()
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if err != nil {
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return err
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}
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defer w.Close()
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dirname := filepath.Dir(fw.Filename)
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// Watch for new files to be created in the parent directory.
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err = w.WatchFlags(dirname, fsnotify.FSN_CREATE)
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if err != nil {
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return err
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}
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defer w.RemoveWatch(filepath.Dir(fw.Filename))
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// Do a real check now as the file might have been created before
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// calling `WatchFlags` above.
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if _, err = os.Stat(fw.Filename); !os.IsNotExist(err) {
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// file exists, or stat returned an error.
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return err
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}
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for {
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evt := <-w.Event
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if evt.Name == fw.Filename {
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break
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}
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}
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return nil
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}
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// ChangeEvents returns a channel that gets updated when the file is ready to be read.
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func (fw *InotifyFileWatcher) ChangeEvents(fi os.FileInfo) chan bool {
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w, err := fsnotify.NewWatcher()
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if err != nil {
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panic(err)
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}
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err = w.Watch(fw.Filename)
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if err != nil {
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panic(err)
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}
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ch := make(chan bool)
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fw.Size = fi.Size()
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go func() {
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defer w.Close()
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defer w.RemoveWatch(fw.Filename)
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defer close(ch)
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for {
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prevSize := fw.Size
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evt := <-w.Event
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switch {
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case evt.IsDelete():
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fallthrough
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case evt.IsRename():
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return
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case evt.IsModify():
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fi, err := os.Stat(fw.Filename)
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if err != nil {
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// XXX: no panic here
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panic(err)
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}
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fw.Size = fi.Size()
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if prevSize > 0 && prevSize > fw.Size {
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return
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}
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// send only if channel is empty.
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select {
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case ch <- true:
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default:
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}
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}
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}
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}()
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return ch
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}
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// PollingFileWatcher polls the file for changes.
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type PollingFileWatcher struct {
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Filename string
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Size int64
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}
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func NewPollingFileWatcher(filename string) *PollingFileWatcher {
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fw := &PollingFileWatcher{filename, 0}
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return fw
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}
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var POLL_DURATION time.Duration
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func (fw *PollingFileWatcher) BlockUntilExists() error {
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for {
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if _, err := os.Stat(fw.Filename); err == nil {
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return nil
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} else if !os.IsNotExist(err) {
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return err
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}
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time.Sleep(POLL_DURATION)
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}
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panic("unreachable")
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}
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func (fw *PollingFileWatcher) ChangeEvents(origFi os.FileInfo) chan bool {
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ch := make(chan bool)
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stop := make(chan bool)
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var once sync.Once
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var prevModTime time.Time
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// XXX: use tomb.Tomb to cleanly manage these goroutines. replace
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// the panic (below) with tomb's Kill.
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stopAndClose := func() {
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go func() {
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close(ch)
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stop <- true
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}()
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}
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fw.Size = origFi.Size()
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go func() {
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prevSize := fw.Size
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for {
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select {
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case <-stop:
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return
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default:
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}
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time.Sleep(POLL_DURATION)
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fi, err := os.Stat(fw.Filename)
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if err != nil {
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if os.IsNotExist(err) {
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once.Do(stopAndClose)
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continue
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}
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/// XXX: do not panic here.
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panic(err)
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}
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// File got moved/rename within POLL_DURATION?
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if !os.SameFile(origFi, fi) {
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once.Do(stopAndClose)
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continue
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}
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// Was the file truncated?
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fw.Size = fi.Size()
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if prevSize > 0 && prevSize > fw.Size {
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once.Do(stopAndClose)
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continue
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}
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// If the file was changed since last check, notify.
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modTime := fi.ModTime()
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if modTime != prevModTime {
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prevModTime = modTime
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select {
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case ch <- true:
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default:
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}
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}
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}
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}()
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return ch
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}
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func init() {
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POLL_DURATION = 250 * time.Millisecond
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}
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@ -0,0 +1,107 @@
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// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
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package watch
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import (
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"github.com/howeyc/fsnotify"
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"os"
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"path/filepath"
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)
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// InotifyFileWatcher uses inotify to monitor file changes.
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type InotifyFileWatcher struct {
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Filename string
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Size int64
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}
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func NewInotifyFileWatcher(filename string) *InotifyFileWatcher {
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fw := &InotifyFileWatcher{filename, 0}
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return fw
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}
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func (fw *InotifyFileWatcher) BlockUntilExists() error {
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w, err := fsnotify.NewWatcher()
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if err != nil {
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return err
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}
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defer w.Close()
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dirname := filepath.Dir(fw.Filename)
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// Watch for new files to be created in the parent directory.
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err = w.WatchFlags(dirname, fsnotify.FSN_CREATE)
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if err != nil {
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return err
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}
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defer w.RemoveWatch(filepath.Dir(fw.Filename))
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// Do a real check now as the file might have been created before
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// calling `WatchFlags` above.
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if _, err = os.Stat(fw.Filename); !os.IsNotExist(err) {
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// file exists, or stat returned an error.
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return err
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}
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for {
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evt := <-w.Event
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if evt.Name == fw.Filename {
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break
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}
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}
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return nil
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}
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// ChangeEvents returns a channel that gets updated when the file is ready to be read.
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func (fw *InotifyFileWatcher) ChangeEvents(fi os.FileInfo) chan bool {
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w, err := fsnotify.NewWatcher()
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if err != nil {
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panic(err)
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}
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err = w.Watch(fw.Filename)
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if err != nil {
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panic(err)
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}
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ch := make(chan bool)
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fw.Size = fi.Size()
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go func() {
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defer w.Close()
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defer w.RemoveWatch(fw.Filename)
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defer close(ch)
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for {
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prevSize := fw.Size
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evt := <-w.Event
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switch {
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case evt.IsDelete():
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fallthrough
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case evt.IsRename():
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return
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case evt.IsModify():
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fi, err := os.Stat(fw.Filename)
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if err != nil {
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// XXX: no panic here
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panic(err)
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}
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fw.Size = fi.Size()
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if prevSize > 0 && prevSize > fw.Size {
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return
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}
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// send only if channel is empty.
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select {
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case ch <- true:
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default:
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}
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}
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}
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}()
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return ch
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}
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@ -0,0 +1,104 @@
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// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
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package watch
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import (
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"os"
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"sync"
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"time"
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)
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// PollingFileWatcher polls the file for changes.
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type PollingFileWatcher struct {
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Filename string
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Size int64
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}
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func NewPollingFileWatcher(filename string) *PollingFileWatcher {
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fw := &PollingFileWatcher{filename, 0}
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return fw
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}
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var POLL_DURATION time.Duration
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func (fw *PollingFileWatcher) BlockUntilExists() error {
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for {
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if _, err := os.Stat(fw.Filename); err == nil {
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return nil
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} else if !os.IsNotExist(err) {
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return err
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}
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time.Sleep(POLL_DURATION)
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}
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panic("unreachable")
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}
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func (fw *PollingFileWatcher) ChangeEvents(origFi os.FileInfo) chan bool {
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ch := make(chan bool)
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stop := make(chan bool)
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var once sync.Once
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var prevModTime time.Time
|
||||
|
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// XXX: use tomb.Tomb to cleanly manage these goroutines. replace
|
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// the panic (below) with tomb's Kill.
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stopAndClose := func() {
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go func() {
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close(ch)
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stop <- true
|
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}()
|
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}
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|
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fw.Size = origFi.Size()
|
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|
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go func() {
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prevSize := fw.Size
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for {
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select {
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case <-stop:
|
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return
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default:
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}
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|
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time.Sleep(POLL_DURATION)
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fi, err := os.Stat(fw.Filename)
|
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if err != nil {
|
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if os.IsNotExist(err) {
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once.Do(stopAndClose)
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continue
|
||||
}
|
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/// XXX: do not panic here.
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panic(err)
|
||||
}
|
||||
|
||||
// File got moved/rename within POLL_DURATION?
|
||||
if !os.SameFile(origFi, fi) {
|
||||
once.Do(stopAndClose)
|
||||
continue
|
||||
}
|
||||
|
||||
// Was the file truncated?
|
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fw.Size = fi.Size()
|
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if prevSize > 0 && prevSize > fw.Size {
|
||||
once.Do(stopAndClose)
|
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continue
|
||||
}
|
||||
|
||||
// If the file was changed since last check, notify.
|
||||
modTime := fi.ModTime()
|
||||
if modTime != prevModTime {
|
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prevModTime = modTime
|
||||
select {
|
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case ch <- true:
|
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default:
|
||||
}
|
||||
}
|
||||
}
|
||||
}()
|
||||
|
||||
return ch
|
||||
}
|
||||
|
||||
func init() {
|
||||
POLL_DURATION = 250 * time.Millisecond
|
||||
}
|
||||
|
|
@ -0,0 +1,19 @@
|
|||
// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
|
||||
|
||||
package watch
|
||||
|
||||
import (
|
||||
"os"
|
||||
)
|
||||
|
||||
// FileWatcher monitors file-level events.
|
||||
type FileWatcher interface {
|
||||
// BlockUntilExists blocks until the missing file comes into
|
||||
// existence. If the file already exists, returns immediately.
|
||||
BlockUntilExists() error
|
||||
|
||||
// ChangeEvents returns a channel of events corresponding to the
|
||||
// times the file is ready to be read.
|
||||
ChangeEvents(os.FileInfo) chan bool
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue