vendor/github.com/fsnotify/fsnotify/kqueue.go
changeset 242 2a9ec03fe5a1
child 260 445e01aede7e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/fsnotify/fsnotify/kqueue.go	Sat Sep 29 18:09:54 2018 +0200
@@ -0,0 +1,521 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build freebsd openbsd netbsd dragonfly darwin
+
+package fsnotify
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"golang.org/x/sys/unix"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events chan Event
+	Errors chan error
+	done   chan struct{} // Channel for sending a "quit message" to the reader goroutine
+
+	kq int // File descriptor (as returned by the kqueue() syscall).
+
+	mu              sync.Mutex        // Protects access to watcher data
+	watches         map[string]int    // Map of watched file descriptors (key: path).
+	externalWatches map[string]bool   // Map of watches added by user of the library.
+	dirFlags        map[string]uint32 // Map of watched directories to fflags used in kqueue.
+	paths           map[int]pathInfo  // Map file descriptors to path names for processing kqueue events.
+	fileExists      map[string]bool   // Keep track of if we know this file exists (to stop duplicate create events).
+	isClosed        bool              // Set to true when Close() is first called
+}
+
+type pathInfo struct {
+	name  string
+	isDir bool
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	kq, err := kqueue()
+	if err != nil {
+		return nil, err
+	}
+
+	w := &Watcher{
+		kq:              kq,
+		watches:         make(map[string]int),
+		dirFlags:        make(map[string]uint32),
+		paths:           make(map[int]pathInfo),
+		fileExists:      make(map[string]bool),
+		externalWatches: make(map[string]bool),
+		Events:          make(chan Event),
+		Errors:          make(chan error),
+		done:            make(chan struct{}),
+	}
+
+	go w.readEvents()
+	return w, nil
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	w.mu.Lock()
+	if w.isClosed {
+		w.mu.Unlock()
+		return nil
+	}
+	w.isClosed = true
+
+	// copy paths to remove while locked
+	var pathsToRemove = make([]string, 0, len(w.watches))
+	for name := range w.watches {
+		pathsToRemove = append(pathsToRemove, name)
+	}
+	w.mu.Unlock()
+	// unlock before calling Remove, which also locks
+
+	for _, name := range pathsToRemove {
+		w.Remove(name)
+	}
+
+	// send a "quit" message to the reader goroutine
+	close(w.done)
+
+	return nil
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	w.mu.Lock()
+	w.externalWatches[name] = true
+	w.mu.Unlock()
+	_, err := w.addWatch(name, noteAllEvents)
+	return err
+}
+
+// Remove stops watching the the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	name = filepath.Clean(name)
+	w.mu.Lock()
+	watchfd, ok := w.watches[name]
+	w.mu.Unlock()
+	if !ok {
+		return fmt.Errorf("can't remove non-existent kevent watch for: %s", name)
+	}
+
+	const registerRemove = unix.EV_DELETE
+	if err := register(w.kq, []int{watchfd}, registerRemove, 0); err != nil {
+		return err
+	}
+
+	unix.Close(watchfd)
+
+	w.mu.Lock()
+	isDir := w.paths[watchfd].isDir
+	delete(w.watches, name)
+	delete(w.paths, watchfd)
+	delete(w.dirFlags, name)
+	w.mu.Unlock()
+
+	// Find all watched paths that are in this directory that are not external.
+	if isDir {
+		var pathsToRemove []string
+		w.mu.Lock()
+		for _, path := range w.paths {
+			wdir, _ := filepath.Split(path.name)
+			if filepath.Clean(wdir) == name {
+				if !w.externalWatches[path.name] {
+					pathsToRemove = append(pathsToRemove, path.name)
+				}
+			}
+		}
+		w.mu.Unlock()
+		for _, name := range pathsToRemove {
+			// Since these are internal, not much sense in propagating error
+			// to the user, as that will just confuse them with an error about
+			// a path they did not explicitly watch themselves.
+			w.Remove(name)
+		}
+	}
+
+	return nil
+}
+
+// Watch all events (except NOTE_EXTEND, NOTE_LINK, NOTE_REVOKE)
+const noteAllEvents = unix.NOTE_DELETE | unix.NOTE_WRITE | unix.NOTE_ATTRIB | unix.NOTE_RENAME
+
+// keventWaitTime to block on each read from kevent
+var keventWaitTime = durationToTimespec(100 * time.Millisecond)
+
+// addWatch adds name to the watched file set.
+// The flags are interpreted as described in kevent(2).
+// Returns the real path to the file which was added, if any, which may be different from the one passed in the case of symlinks.
+func (w *Watcher) addWatch(name string, flags uint32) (string, error) {
+	var isDir bool
+	// Make ./name and name equivalent
+	name = filepath.Clean(name)
+
+	w.mu.Lock()
+	if w.isClosed {
+		w.mu.Unlock()
+		return "", errors.New("kevent instance already closed")
+	}
+	watchfd, alreadyWatching := w.watches[name]
+	// We already have a watch, but we can still override flags.
+	if alreadyWatching {
+		isDir = w.paths[watchfd].isDir
+	}
+	w.mu.Unlock()
+
+	if !alreadyWatching {
+		fi, err := os.Lstat(name)
+		if err != nil {
+			return "", err
+		}
+
+		// Don't watch sockets.
+		if fi.Mode()&os.ModeSocket == os.ModeSocket {
+			return "", nil
+		}
+
+		// Don't watch named pipes.
+		if fi.Mode()&os.ModeNamedPipe == os.ModeNamedPipe {
+			return "", nil
+		}
+
+		// Follow Symlinks
+		// Unfortunately, Linux can add bogus symlinks to watch list without
+		// issue, and Windows can't do symlinks period (AFAIK). To  maintain
+		// consistency, we will act like everything is fine. There will simply
+		// be no file events for broken symlinks.
+		// Hence the returns of nil on errors.
+		if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
+			name, err = filepath.EvalSymlinks(name)
+			if err != nil {
+				return "", nil
+			}
+
+			w.mu.Lock()
+			_, alreadyWatching = w.watches[name]
+			w.mu.Unlock()
+
+			if alreadyWatching {
+				return name, nil
+			}
+
+			fi, err = os.Lstat(name)
+			if err != nil {
+				return "", nil
+			}
+		}
+
+		watchfd, err = unix.Open(name, openMode, 0700)
+		if watchfd == -1 {
+			return "", err
+		}
+
+		isDir = fi.IsDir()
+	}
+
+	const registerAdd = unix.EV_ADD | unix.EV_CLEAR | unix.EV_ENABLE
+	if err := register(w.kq, []int{watchfd}, registerAdd, flags); err != nil {
+		unix.Close(watchfd)
+		return "", err
+	}
+
+	if !alreadyWatching {
+		w.mu.Lock()
+		w.watches[name] = watchfd
+		w.paths[watchfd] = pathInfo{name: name, isDir: isDir}
+		w.mu.Unlock()
+	}
+
+	if isDir {
+		// Watch the directory if it has not been watched before,
+		// or if it was watched before, but perhaps only a NOTE_DELETE (watchDirectoryFiles)
+		w.mu.Lock()
+
+		watchDir := (flags&unix.NOTE_WRITE) == unix.NOTE_WRITE &&
+			(!alreadyWatching || (w.dirFlags[name]&unix.NOTE_WRITE) != unix.NOTE_WRITE)
+		// Store flags so this watch can be updated later
+		w.dirFlags[name] = flags
+		w.mu.Unlock()
+
+		if watchDir {
+			if err := w.watchDirectoryFiles(name); err != nil {
+				return "", err
+			}
+		}
+	}
+	return name, nil
+}
+
+// readEvents reads from kqueue and converts the received kevents into
+// Event values that it sends down the Events channel.
+func (w *Watcher) readEvents() {
+	eventBuffer := make([]unix.Kevent_t, 10)
+
+loop:
+	for {
+		// See if there is a message on the "done" channel
+		select {
+		case <-w.done:
+			break loop
+		default:
+		}
+
+		// Get new events
+		kevents, err := read(w.kq, eventBuffer, &keventWaitTime)
+		// EINTR is okay, the syscall was interrupted before timeout expired.
+		if err != nil && err != unix.EINTR {
+			select {
+			case w.Errors <- err:
+			case <-w.done:
+				break loop
+			}
+			continue
+		}
+
+		// Flush the events we received to the Events channel
+		for len(kevents) > 0 {
+			kevent := &kevents[0]
+			watchfd := int(kevent.Ident)
+			mask := uint32(kevent.Fflags)
+			w.mu.Lock()
+			path := w.paths[watchfd]
+			w.mu.Unlock()
+			event := newEvent(path.name, mask)
+
+			if path.isDir && !(event.Op&Remove == Remove) {
+				// Double check to make sure the directory exists. This can happen when
+				// we do a rm -fr on a recursively watched folders and we receive a
+				// modification event first but the folder has been deleted and later
+				// receive the delete event
+				if _, err := os.Lstat(event.Name); os.IsNotExist(err) {
+					// mark is as delete event
+					event.Op |= Remove
+				}
+			}
+
+			if event.Op&Rename == Rename || event.Op&Remove == Remove {
+				w.Remove(event.Name)
+				w.mu.Lock()
+				delete(w.fileExists, event.Name)
+				w.mu.Unlock()
+			}
+
+			if path.isDir && event.Op&Write == Write && !(event.Op&Remove == Remove) {
+				w.sendDirectoryChangeEvents(event.Name)
+			} else {
+				// Send the event on the Events channel.
+				select {
+				case w.Events <- event:
+				case <-w.done:
+					break loop
+				}
+			}
+
+			if event.Op&Remove == Remove {
+				// Look for a file that may have overwritten this.
+				// For example, mv f1 f2 will delete f2, then create f2.
+				if path.isDir {
+					fileDir := filepath.Clean(event.Name)
+					w.mu.Lock()
+					_, found := w.watches[fileDir]
+					w.mu.Unlock()
+					if found {
+						// make sure the directory exists before we watch for changes. When we
+						// do a recursive watch and perform rm -fr, the parent directory might
+						// have gone missing, ignore the missing directory and let the
+						// upcoming delete event remove the watch from the parent directory.
+						if _, err := os.Lstat(fileDir); err == nil {
+							w.sendDirectoryChangeEvents(fileDir)
+						}
+					}
+				} else {
+					filePath := filepath.Clean(event.Name)
+					if fileInfo, err := os.Lstat(filePath); err == nil {
+						w.sendFileCreatedEventIfNew(filePath, fileInfo)
+					}
+				}
+			}
+
+			// Move to next event
+			kevents = kevents[1:]
+		}
+	}
+
+	// cleanup
+	err := unix.Close(w.kq)
+	if err != nil {
+		// only way the previous loop breaks is if w.done was closed so we need to async send to w.Errors.
+		select {
+		case w.Errors <- err:
+		default:
+		}
+	}
+	close(w.Events)
+	close(w.Errors)
+}
+
+// newEvent returns an platform-independent Event based on kqueue Fflags.
+func newEvent(name string, mask uint32) Event {
+	e := Event{Name: name}
+	if mask&unix.NOTE_DELETE == unix.NOTE_DELETE {
+		e.Op |= Remove
+	}
+	if mask&unix.NOTE_WRITE == unix.NOTE_WRITE {
+		e.Op |= Write
+	}
+	if mask&unix.NOTE_RENAME == unix.NOTE_RENAME {
+		e.Op |= Rename
+	}
+	if mask&unix.NOTE_ATTRIB == unix.NOTE_ATTRIB {
+		e.Op |= Chmod
+	}
+	return e
+}
+
+func newCreateEvent(name string) Event {
+	return Event{Name: name, Op: Create}
+}
+
+// watchDirectoryFiles to mimic inotify when adding a watch on a directory
+func (w *Watcher) watchDirectoryFiles(dirPath string) error {
+	// Get all files
+	files, err := ioutil.ReadDir(dirPath)
+	if err != nil {
+		return err
+	}
+
+	for _, fileInfo := range files {
+		filePath := filepath.Join(dirPath, fileInfo.Name())
+		filePath, err = w.internalWatch(filePath, fileInfo)
+		if err != nil {
+			return err
+		}
+
+		w.mu.Lock()
+		w.fileExists[filePath] = true
+		w.mu.Unlock()
+	}
+
+	return nil
+}
+
+// sendDirectoryEvents searches the directory for newly created files
+// and sends them over the event channel. This functionality is to have
+// the BSD version of fsnotify match Linux inotify which provides a
+// create event for files created in a watched directory.
+func (w *Watcher) sendDirectoryChangeEvents(dirPath string) {
+	// Get all files
+	files, err := ioutil.ReadDir(dirPath)
+	if err != nil {
+		select {
+		case w.Errors <- err:
+		case <-w.done:
+			return
+		}
+	}
+
+	// Search for new files
+	for _, fileInfo := range files {
+		filePath := filepath.Join(dirPath, fileInfo.Name())
+		err := w.sendFileCreatedEventIfNew(filePath, fileInfo)
+
+		if err != nil {
+			return
+		}
+	}
+}
+
+// sendFileCreatedEvent sends a create event if the file isn't already being tracked.
+func (w *Watcher) sendFileCreatedEventIfNew(filePath string, fileInfo os.FileInfo) (err error) {
+	w.mu.Lock()
+	_, doesExist := w.fileExists[filePath]
+	w.mu.Unlock()
+	if !doesExist {
+		// Send create event
+		select {
+		case w.Events <- newCreateEvent(filePath):
+		case <-w.done:
+			return
+		}
+	}
+
+	// like watchDirectoryFiles (but without doing another ReadDir)
+	filePath, err = w.internalWatch(filePath, fileInfo)
+	if err != nil {
+		return err
+	}
+
+	w.mu.Lock()
+	w.fileExists[filePath] = true
+	w.mu.Unlock()
+
+	return nil
+}
+
+func (w *Watcher) internalWatch(name string, fileInfo os.FileInfo) (string, error) {
+	if fileInfo.IsDir() {
+		// mimic Linux providing delete events for subdirectories
+		// but preserve the flags used if currently watching subdirectory
+		w.mu.Lock()
+		flags := w.dirFlags[name]
+		w.mu.Unlock()
+
+		flags |= unix.NOTE_DELETE | unix.NOTE_RENAME
+		return w.addWatch(name, flags)
+	}
+
+	// watch file to mimic Linux inotify
+	return w.addWatch(name, noteAllEvents)
+}
+
+// kqueue creates a new kernel event queue and returns a descriptor.
+func kqueue() (kq int, err error) {
+	kq, err = unix.Kqueue()
+	if kq == -1 {
+		return kq, err
+	}
+	return kq, nil
+}
+
+// register events with the queue
+func register(kq int, fds []int, flags int, fflags uint32) error {
+	changes := make([]unix.Kevent_t, len(fds))
+
+	for i, fd := range fds {
+		// SetKevent converts int to the platform-specific types:
+		unix.SetKevent(&changes[i], fd, unix.EVFILT_VNODE, flags)
+		changes[i].Fflags = fflags
+	}
+
+	// register the events
+	success, err := unix.Kevent(kq, changes, nil, nil)
+	if success == -1 {
+		return err
+	}
+	return nil
+}
+
+// read retrieves pending events, or waits until an event occurs.
+// A timeout of nil blocks indefinitely, while 0 polls the queue.
+func read(kq int, events []unix.Kevent_t, timeout *unix.Timespec) ([]unix.Kevent_t, error) {
+	n, err := unix.Kevent(kq, nil, events, timeout)
+	if err != nil {
+		return nil, err
+	}
+	return events[0:n], nil
+}
+
+// durationToTimespec prepares a timeout value
+func durationToTimespec(d time.Duration) unix.Timespec {
+	return unix.NsecToTimespec(d.Nanoseconds())
+}