diff options
Diffstat (limited to 'vendor/github.com/fsnotify/fsnotify/kqueue.go')
-rw-r--r-- | vendor/github.com/fsnotify/fsnotify/kqueue.go | 521 |
1 files changed, 521 insertions, 0 deletions
diff --git a/vendor/github.com/fsnotify/fsnotify/kqueue.go b/vendor/github.com/fsnotify/fsnotify/kqueue.go new file mode 100644 index 00000000..86e76a3d --- /dev/null +++ b/vendor/github.com/fsnotify/fsnotify/kqueue.go @@ -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()) +} |