1 files changed, 260 insertions, 0 deletions
diff --git a/vendor/github.com/hpcloud/tail/watch/inotify_tracker.go b/vendor/github.com/hpcloud/tail/watch/inotify_tracker.go
new file mode 100644
index 000000000..03be4275c
--- /dev/null
+++ b/vendor/github.com/hpcloud/tail/watch/inotify_tracker.go
@@ -0,0 +1,260 @@
+// Copyright (c) 2015 HPE Software Inc. All rights reserved.
+// Copyright (c) 2013 ActiveState Software Inc. All rights reserved.
+
+package watch
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"sync"
+	"syscall"
+
+	"github.com/hpcloud/tail/util"
+
+	"gopkg.in/fsnotify.v1"
+)
+
+type InotifyTracker struct {
+	mux       sync.Mutex
+	watcher   *fsnotify.Watcher
+	chans     map[string]chan fsnotify.Event
+	done      map[string]chan bool
+	watchNums map[string]int
+	watch     chan *watchInfo
+	remove    chan *watchInfo
+	error     chan error
+}
+
+type watchInfo struct {
+	op    fsnotify.Op
+	fname string
+}
+
+func (this *watchInfo) isCreate() bool {
+	return this.op == fsnotify.Create
+}
+
+var (
+	// globally shared InotifyTracker; ensures only one fsnotify.Watcher is used
+	shared *InotifyTracker
+
+	// these are used to ensure the shared InotifyTracker is run exactly once
+	once  = sync.Once{}
+	goRun = func() {
+		shared = &InotifyTracker{
+			mux:       sync.Mutex{},
+			chans:     make(map[string]chan fsnotify.Event),
+			done:      make(map[string]chan bool),
+			watchNums: make(map[string]int),
+			watch:     make(chan *watchInfo),
+			remove:    make(chan *watchInfo),
+			error:     make(chan error),
+		}
+		go shared.run()
+	}
+
+	logger = log.New(os.Stderr, "", log.LstdFlags)
+)
+
+// Watch signals the run goroutine to begin watching the input filename
+func Watch(fname string) error {
+	return watch(&watchInfo{
+		fname: fname,
+	})
+}
+
+// Watch create signals the run goroutine to begin watching the input filename
+// if call the WatchCreate function, don't call the Cleanup, call the RemoveWatchCreate
+func WatchCreate(fname string) error {
+	return watch(&watchInfo{
+		op:    fsnotify.Create,
+		fname: fname,
+	})
+}
+
+func watch(winfo *watchInfo) error {
+	// start running the shared InotifyTracker if not already running
+	once.Do(goRun)
+
+	winfo.fname = filepath.Clean(winfo.fname)
+	shared.watch <- winfo
+	return <-shared.error
+}
+
+// RemoveWatch signals the run goroutine to remove the watch for the input filename
+func RemoveWatch(fname string) {
+	remove(&watchInfo{
+		fname: fname,
+	})
+}
+
+// RemoveWatch create signals the run goroutine to remove the watch for the input filename
+func RemoveWatchCreate(fname string) {
+	remove(&watchInfo{
+		op:    fsnotify.Create,
+		fname: fname,
+	})
+}
+
+func remove(winfo *watchInfo) {
+	// start running the shared InotifyTracker if not already running
+	once.Do(goRun)
+
+	winfo.fname = filepath.Clean(winfo.fname)
+	shared.mux.Lock()
+	done := shared.done[winfo.fname]
+	if done != nil {
+		delete(shared.done, winfo.fname)
+		close(done)
+	}
+
+	fname := winfo.fname
+	if winfo.isCreate() {
+		// Watch for new files to be created in the parent directory.
+		fname = filepath.Dir(fname)
+	}
+	shared.watchNums[fname]--
+	watchNum := shared.watchNums[fname]
+	if watchNum == 0 {
+		delete(shared.watchNums, fname)
+	}
+	shared.mux.Unlock()
+
+	// If we were the last ones to watch this file, unsubscribe from inotify.
+	// This needs to happen after releasing the lock because fsnotify waits
+	// synchronously for the kernel to acknowledge the removal of the watch
+	// for this file, which causes us to deadlock if we still held the lock.
+	if watchNum == 0 {
+		shared.watcher.Remove(fname)
+	}
+	shared.remove <- winfo
+}
+
+// Events returns a channel to which FileEvents corresponding to the input filename
+// will be sent. This channel will be closed when removeWatch is called on this
+// filename.
+func Events(fname string) <-chan fsnotify.Event {
+	shared.mux.Lock()
+	defer shared.mux.Unlock()
+
+	return shared.chans[fname]
+}
+
+// Cleanup removes the watch for the input filename if necessary.
+func Cleanup(fname string) {
+	RemoveWatch(fname)
+}
+
+// watchFlags calls fsnotify.WatchFlags for the input filename and flags, creating
+// a new Watcher if the previous Watcher was closed.
+func (shared *InotifyTracker) addWatch(winfo *watchInfo) error {
+	shared.mux.Lock()
+	defer shared.mux.Unlock()
+
+	if shared.chans[winfo.fname] == nil {
+		shared.chans[winfo.fname] = make(chan fsnotify.Event)
+		shared.done[winfo.fname] = make(chan bool)
+	}
+
+	fname := winfo.fname
+	if winfo.isCreate() {
+		// Watch for new files to be created in the parent directory.
+		fname = filepath.Dir(fname)
+	}
+
+	// already in inotify watch
+	if shared.watchNums[fname] > 0 {
+		shared.watchNums[fname]++
+		if winfo.isCreate() {
+			shared.watchNums[winfo.fname]++
+		}
+		return nil
+	}
+
+	err := shared.watcher.Add(fname)
+	if err == nil {
+		shared.watchNums[fname]++
+		if winfo.isCreate() {
+			shared.watchNums[winfo.fname]++
+		}
+	}
+	return err
+}
+
+// removeWatch calls fsnotify.RemoveWatch for the input filename and closes the
+// corresponding events channel.
+func (shared *InotifyTracker) removeWatch(winfo *watchInfo) {
+	shared.mux.Lock()
+	defer shared.mux.Unlock()
+
+	ch := shared.chans[winfo.fname]
+	if ch == nil {
+		return
+	}
+
+	delete(shared.chans, winfo.fname)
+	close(ch)
+
+	if !winfo.isCreate() {
+		return
+	}
+
+	shared.watchNums[winfo.fname]--
+	if shared.watchNums[winfo.fname] == 0 {
+		delete(shared.watchNums, winfo.fname)
+	}
+}
+
+// sendEvent sends the input event to the appropriate Tail.
+func (shared *InotifyTracker) sendEvent(event fsnotify.Event) {
+	name := filepath.Clean(event.Name)
+
+	shared.mux.Lock()
+	ch := shared.chans[name]
+	done := shared.done[name]
+	shared.mux.Unlock()
+
+	if ch != nil && done != nil {
+		select {
+		case ch <- event:
+		case <-done:
+		}
+	}
+}
+
+// run starts the goroutine in which the shared struct reads events from its
+// Watcher's Event channel and sends the events to the appropriate Tail.
+func (shared *InotifyTracker) run() {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		util.Fatal("failed to create Watcher")
+	}
+	shared.watcher = watcher
+
+	for {
+		select {
+		case winfo := <-shared.watch:
+			shared.error <- shared.addWatch(winfo)
+
+		case winfo := <-shared.remove:
+			shared.removeWatch(winfo)
+
+		case event, open := <-shared.watcher.Events:
+			if !open {
+				return
+			}
+			shared.sendEvent(event)
+
+		case err, open := <-shared.watcher.Errors:
+			if !open {
+				return
+			} else if err != nil {
+				sysErr, ok := err.(*os.SyscallError)
+				if !ok || sysErr.Err != syscall.EINTR {
+					logger.Printf("Error in Watcher Error channel: %s", err)
+				}
+			}
+		}
+	}
+}