/usr/share/gocode/src/golang.org/x/exp/winfsnotify/winfsnotify.go is in golang-golang-x-exp-dev 0.0~git20150826.1.eb7c1fa-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 | // Copyright 2011 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 windows
// Package winfsnotify allows the user to receive
// file system event notifications on Windows.
package winfsnotify // import "golang.org/x/exp/winfsnotify"
import (
"errors"
"fmt"
"os"
"path/filepath"
"runtime"
"syscall"
"unsafe"
)
// Event is the type of the notification messages
// received on the watcher's Event channel.
type Event struct {
Mask uint32 // Mask of events
Cookie uint32 // Unique cookie associating related events (for rename)
Name string // File name (optional)
}
const (
opAddWatch = iota
opRemoveWatch
)
const (
provisional uint64 = 1 << (32 + iota)
)
type input struct {
op int
path string
flags uint32
reply chan error
}
type inode struct {
handle syscall.Handle
volume uint32
index uint64
}
type watch struct {
ov syscall.Overlapped
ino *inode // i-number
path string // Directory path
mask uint64 // Directory itself is being watched with these notify flags
names map[string]uint64 // Map of names being watched and their notify flags
rename string // Remembers the old name while renaming a file
buf [4096]byte
}
type indexMap map[uint64]*watch
type watchMap map[uint32]indexMap
// A Watcher waits for and receives event notifications
// for a specific set of files and directories.
type Watcher struct {
port syscall.Handle // Handle to completion port
watches watchMap // Map of watches (key: i-number)
input chan *input // Inputs to the reader are sent on this channel
Event chan *Event // Events are returned on this channel
Error chan error // Errors are sent on this channel
isClosed bool // Set to true when Close() is first called
quit chan chan<- error
cookie uint32
}
// NewWatcher creates and returns a Watcher.
func NewWatcher() (*Watcher, error) {
port, e := syscall.CreateIoCompletionPort(syscall.InvalidHandle, 0, 0, 0)
if e != nil {
return nil, os.NewSyscallError("CreateIoCompletionPort", e)
}
w := &Watcher{
port: port,
watches: make(watchMap),
input: make(chan *input, 1),
Event: make(chan *Event, 50),
Error: make(chan error),
quit: make(chan chan<- error, 1),
}
go w.readEvents()
return w, nil
}
// Close closes a Watcher.
// It sends a message to the reader goroutine to quit and removes all watches
// associated with the watcher.
func (w *Watcher) Close() error {
if w.isClosed {
return nil
}
w.isClosed = true
// Send "quit" message to the reader goroutine
ch := make(chan error)
w.quit <- ch
if err := w.wakeupReader(); err != nil {
return err
}
return <-ch
}
// AddWatch adds path to the watched file set.
func (w *Watcher) AddWatch(path string, flags uint32) error {
if w.isClosed {
return errors.New("watcher already closed")
}
in := &input{
op: opAddWatch,
path: filepath.Clean(path),
flags: flags,
reply: make(chan error),
}
w.input <- in
if err := w.wakeupReader(); err != nil {
return err
}
return <-in.reply
}
// Watch adds path to the watched file set, watching all events.
func (w *Watcher) Watch(path string) error {
return w.AddWatch(path, FS_ALL_EVENTS)
}
// RemoveWatch removes path from the watched file set.
func (w *Watcher) RemoveWatch(path string) error {
in := &input{
op: opRemoveWatch,
path: filepath.Clean(path),
reply: make(chan error),
}
w.input <- in
if err := w.wakeupReader(); err != nil {
return err
}
return <-in.reply
}
func (w *Watcher) wakeupReader() error {
e := syscall.PostQueuedCompletionStatus(w.port, 0, 0, nil)
if e != nil {
return os.NewSyscallError("PostQueuedCompletionStatus", e)
}
return nil
}
func getDir(pathname string) (dir string, err error) {
pathnamep, e := syscall.UTF16PtrFromString(pathname)
if e != nil {
return "", e
}
attr, e := syscall.GetFileAttributes(pathnamep)
if e != nil {
return "", os.NewSyscallError("GetFileAttributes", e)
}
if attr&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
dir = pathname
} else {
dir, _ = filepath.Split(pathname)
dir = filepath.Clean(dir)
}
return
}
func getIno(path string) (ino *inode, err error) {
pathp, e := syscall.UTF16PtrFromString(path)
if e != nil {
return nil, e
}
h, e := syscall.CreateFile(pathp,
syscall.FILE_LIST_DIRECTORY,
syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
nil, syscall.OPEN_EXISTING,
syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OVERLAPPED, 0)
if e != nil {
return nil, os.NewSyscallError("CreateFile", e)
}
var fi syscall.ByHandleFileInformation
if e = syscall.GetFileInformationByHandle(h, &fi); e != nil {
syscall.CloseHandle(h)
return nil, os.NewSyscallError("GetFileInformationByHandle", e)
}
ino = &inode{
handle: h,
volume: fi.VolumeSerialNumber,
index: uint64(fi.FileIndexHigh)<<32 | uint64(fi.FileIndexLow),
}
return ino, nil
}
// Must run within the I/O thread.
func (m watchMap) get(ino *inode) *watch {
if i := m[ino.volume]; i != nil {
return i[ino.index]
}
return nil
}
// Must run within the I/O thread.
func (m watchMap) set(ino *inode, watch *watch) {
i := m[ino.volume]
if i == nil {
i = make(indexMap)
m[ino.volume] = i
}
i[ino.index] = watch
}
// Must run within the I/O thread.
func (w *Watcher) addWatch(pathname string, flags uint64) error {
dir, err := getDir(pathname)
if err != nil {
return err
}
if flags&FS_ONLYDIR != 0 && pathname != dir {
return nil
}
ino, err := getIno(dir)
if err != nil {
return err
}
watchEntry := w.watches.get(ino)
if watchEntry == nil {
if _, e := syscall.CreateIoCompletionPort(ino.handle, w.port, 0, 0); e != nil {
syscall.CloseHandle(ino.handle)
return os.NewSyscallError("CreateIoCompletionPort", e)
}
watchEntry = &watch{
ino: ino,
path: dir,
names: make(map[string]uint64),
}
w.watches.set(ino, watchEntry)
flags |= provisional
} else {
syscall.CloseHandle(ino.handle)
}
if pathname == dir {
watchEntry.mask |= flags
} else {
watchEntry.names[filepath.Base(pathname)] |= flags
}
if err = w.startRead(watchEntry); err != nil {
return err
}
if pathname == dir {
watchEntry.mask &= ^provisional
} else {
watchEntry.names[filepath.Base(pathname)] &= ^provisional
}
return nil
}
// Must run within the I/O thread.
func (w *Watcher) removeWatch(pathname string) error {
dir, err := getDir(pathname)
if err != nil {
return err
}
ino, err := getIno(dir)
if err != nil {
return err
}
watch := w.watches.get(ino)
if watch == nil {
return fmt.Errorf("can't remove non-existent watch for: %s", pathname)
}
if pathname == dir {
w.sendEvent(watch.path, watch.mask&FS_IGNORED)
watch.mask = 0
} else {
name := filepath.Base(pathname)
w.sendEvent(watch.path+"/"+name, watch.names[name]&FS_IGNORED)
delete(watch.names, name)
}
return w.startRead(watch)
}
// Must run within the I/O thread.
func (w *Watcher) deleteWatch(watch *watch) {
for name, mask := range watch.names {
if mask&provisional == 0 {
w.sendEvent(watch.path+"/"+name, mask&FS_IGNORED)
}
delete(watch.names, name)
}
if watch.mask != 0 {
if watch.mask&provisional == 0 {
w.sendEvent(watch.path, watch.mask&FS_IGNORED)
}
watch.mask = 0
}
}
// Must run within the I/O thread.
func (w *Watcher) startRead(watch *watch) error {
if e := syscall.CancelIo(watch.ino.handle); e != nil {
w.Error <- os.NewSyscallError("CancelIo", e)
w.deleteWatch(watch)
}
mask := toWindowsFlags(watch.mask)
for _, m := range watch.names {
mask |= toWindowsFlags(m)
}
if mask == 0 {
if e := syscall.CloseHandle(watch.ino.handle); e != nil {
w.Error <- os.NewSyscallError("CloseHandle", e)
}
delete(w.watches[watch.ino.volume], watch.ino.index)
return nil
}
e := syscall.ReadDirectoryChanges(watch.ino.handle, &watch.buf[0],
uint32(unsafe.Sizeof(watch.buf)), false, mask, nil, &watch.ov, 0)
if e != nil {
err := os.NewSyscallError("ReadDirectoryChanges", e)
if e == syscall.ERROR_ACCESS_DENIED && watch.mask&provisional == 0 {
// Watched directory was probably removed
if w.sendEvent(watch.path, watch.mask&FS_DELETE_SELF) {
if watch.mask&FS_ONESHOT != 0 {
watch.mask = 0
}
}
err = nil
}
w.deleteWatch(watch)
w.startRead(watch)
return err
}
return nil
}
// readEvents reads from the I/O completion port, converts the
// received events into Event objects and sends them via the Event channel.
// Entry point to the I/O thread.
func (w *Watcher) readEvents() {
var (
n, key uint32
ov *syscall.Overlapped
)
runtime.LockOSThread()
for {
e := syscall.GetQueuedCompletionStatus(w.port, &n, &key, &ov, syscall.INFINITE)
watch := (*watch)(unsafe.Pointer(ov))
if watch == nil {
select {
case ch := <-w.quit:
for _, index := range w.watches {
for _, watch := range index {
w.deleteWatch(watch)
w.startRead(watch)
}
}
var err error
if e := syscall.CloseHandle(w.port); e != nil {
err = os.NewSyscallError("CloseHandle", e)
}
close(w.Event)
close(w.Error)
ch <- err
return
case in := <-w.input:
switch in.op {
case opAddWatch:
in.reply <- w.addWatch(in.path, uint64(in.flags))
case opRemoveWatch:
in.reply <- w.removeWatch(in.path)
}
default:
}
continue
}
switch e {
case syscall.ERROR_ACCESS_DENIED:
// Watched directory was probably removed
w.sendEvent(watch.path, watch.mask&FS_DELETE_SELF)
w.deleteWatch(watch)
w.startRead(watch)
continue
case syscall.ERROR_OPERATION_ABORTED:
// CancelIo was called on this handle
continue
default:
w.Error <- os.NewSyscallError("GetQueuedCompletionPort", e)
continue
case nil:
}
var offset uint32
for {
if n == 0 {
w.Event <- &Event{Mask: FS_Q_OVERFLOW}
w.Error <- errors.New("short read in readEvents()")
break
}
// Point "raw" to the event in the buffer
raw := (*syscall.FileNotifyInformation)(unsafe.Pointer(&watch.buf[offset]))
buf := (*[syscall.MAX_PATH]uint16)(unsafe.Pointer(&raw.FileName))
name := syscall.UTF16ToString(buf[:raw.FileNameLength/2])
fullname := watch.path + "/" + name
var mask uint64
switch raw.Action {
case syscall.FILE_ACTION_REMOVED:
mask = FS_DELETE_SELF
case syscall.FILE_ACTION_MODIFIED:
mask = FS_MODIFY
case syscall.FILE_ACTION_RENAMED_OLD_NAME:
watch.rename = name
case syscall.FILE_ACTION_RENAMED_NEW_NAME:
if watch.names[watch.rename] != 0 {
watch.names[name] |= watch.names[watch.rename]
delete(watch.names, watch.rename)
mask = FS_MOVE_SELF
}
}
sendNameEvent := func() {
if w.sendEvent(fullname, watch.names[name]&mask) {
if watch.names[name]&FS_ONESHOT != 0 {
delete(watch.names, name)
}
}
}
if raw.Action != syscall.FILE_ACTION_RENAMED_NEW_NAME {
sendNameEvent()
}
if raw.Action == syscall.FILE_ACTION_REMOVED {
w.sendEvent(fullname, watch.names[name]&FS_IGNORED)
delete(watch.names, name)
}
if w.sendEvent(fullname, watch.mask&toFSnotifyFlags(raw.Action)) {
if watch.mask&FS_ONESHOT != 0 {
watch.mask = 0
}
}
if raw.Action == syscall.FILE_ACTION_RENAMED_NEW_NAME {
fullname = watch.path + "/" + watch.rename
sendNameEvent()
}
// Move to the next event in the buffer
if raw.NextEntryOffset == 0 {
break
}
offset += raw.NextEntryOffset
}
if err := w.startRead(watch); err != nil {
w.Error <- err
}
}
}
func (w *Watcher) sendEvent(name string, mask uint64) bool {
if mask == 0 {
return false
}
event := &Event{Mask: uint32(mask), Name: name}
if mask&FS_MOVE != 0 {
if mask&FS_MOVED_FROM != 0 {
w.cookie++
}
event.Cookie = w.cookie
}
select {
case ch := <-w.quit:
w.quit <- ch
case w.Event <- event:
}
return true
}
// String formats the event e in the form
// "filename: 0xEventMask = FS_ACCESS|FS_ATTRIB_|..."
func (e *Event) String() string {
var events string
m := e.Mask
for _, b := range eventBits {
if m&b.Value != 0 {
m &^= b.Value
events += "|" + b.Name
}
}
if m != 0 {
events += fmt.Sprintf("|%#x", m)
}
if len(events) > 0 {
events = " == " + events[1:]
}
return fmt.Sprintf("%q: %#x%s", e.Name, e.Mask, events)
}
func toWindowsFlags(mask uint64) uint32 {
var m uint32
if mask&FS_ACCESS != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_LAST_ACCESS
}
if mask&FS_MODIFY != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_LAST_WRITE
}
if mask&FS_ATTRIB != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_ATTRIBUTES
}
if mask&(FS_MOVE|FS_CREATE|FS_DELETE) != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_FILE_NAME | syscall.FILE_NOTIFY_CHANGE_DIR_NAME
}
return m
}
func toFSnotifyFlags(action uint32) uint64 {
switch action {
case syscall.FILE_ACTION_ADDED:
return FS_CREATE
case syscall.FILE_ACTION_REMOVED:
return FS_DELETE
case syscall.FILE_ACTION_MODIFIED:
return FS_MODIFY
case syscall.FILE_ACTION_RENAMED_OLD_NAME:
return FS_MOVED_FROM
case syscall.FILE_ACTION_RENAMED_NEW_NAME:
return FS_MOVED_TO
}
return 0
}
const (
// Options for AddWatch
FS_ONESHOT = 0x80000000
FS_ONLYDIR = 0x1000000
// Events
FS_ACCESS = 0x1
FS_ALL_EVENTS = 0xfff
FS_ATTRIB = 0x4
FS_CLOSE = 0x18
FS_CREATE = 0x100
FS_DELETE = 0x200
FS_DELETE_SELF = 0x400
FS_MODIFY = 0x2
FS_MOVE = 0xc0
FS_MOVED_FROM = 0x40
FS_MOVED_TO = 0x80
FS_MOVE_SELF = 0x800
// Special events
FS_IGNORED = 0x8000
FS_Q_OVERFLOW = 0x4000
)
var eventBits = []struct {
Value uint32
Name string
}{
{FS_ACCESS, "FS_ACCESS"},
{FS_ATTRIB, "FS_ATTRIB"},
{FS_CREATE, "FS_CREATE"},
{FS_DELETE, "FS_DELETE"},
{FS_DELETE_SELF, "FS_DELETE_SELF"},
{FS_MODIFY, "FS_MODIFY"},
{FS_MOVED_FROM, "FS_MOVED_FROM"},
{FS_MOVED_TO, "FS_MOVED_TO"},
{FS_MOVE_SELF, "FS_MOVE_SELF"},
{FS_IGNORED, "FS_IGNORED"},
{FS_Q_OVERFLOW, "FS_Q_OVERFLOW"},
}
|