gitea/vendor/github.com/fsnotify/fsnotify/windows.go

562 lines
13 KiB
Go

// 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 fsnotify
import (
"errors"
"fmt"
"os"
"path/filepath"
"runtime"
"sync"
"syscall"
"unsafe"
)
// Watcher watches a set of files, delivering events to a channel.
type Watcher struct {
Events chan Event
Errors chan error
isClosed bool // Set to true when Close() is first called
mu sync.Mutex // Map access
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
quit chan chan<- error
}
// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
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),
Events: make(chan Event, 50),
Errors: make(chan error),
quit: make(chan chan<- error, 1),
}
go w.readEvents()
return w, nil
}
// Close removes all watches and closes the events channel.
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
}
// Add starts watching the named file or directory (non-recursively).
func (w *Watcher) Add(name string) error {
if w.isClosed {
return errors.New("watcher already closed")
}
in := &input{
op: opAddWatch,
path: filepath.Clean(name),
flags: sysFSALLEVENTS,
reply: make(chan error),
}
w.input <- in
if err := w.wakeupReader(); err != nil {
return err
}
return <-in.reply
}
// Remove stops watching the the named file or directory (non-recursively).
func (w *Watcher) Remove(name string) error {
in := &input{
op: opRemoveWatch,
path: filepath.Clean(name),
reply: make(chan error),
}
w.input <- in
if err := w.wakeupReader(); err != nil {
return err
}
return <-in.reply
}
const (
// Options for AddWatch
sysFSONESHOT = 0x80000000
sysFSONLYDIR = 0x1000000
// Events
sysFSACCESS = 0x1
sysFSALLEVENTS = 0xfff
sysFSATTRIB = 0x4
sysFSCLOSE = 0x18
sysFSCREATE = 0x100
sysFSDELETE = 0x200
sysFSDELETESELF = 0x400
sysFSMODIFY = 0x2
sysFSMOVE = 0xc0
sysFSMOVEDFROM = 0x40
sysFSMOVEDTO = 0x80
sysFSMOVESELF = 0x800
// Special events
sysFSIGNORED = 0x8000
sysFSQOVERFLOW = 0x4000
)
func newEvent(name string, mask uint32) Event {
e := Event{Name: name}
if mask&sysFSCREATE == sysFSCREATE || mask&sysFSMOVEDTO == sysFSMOVEDTO {
e.Op |= Create
}
if mask&sysFSDELETE == sysFSDELETE || mask&sysFSDELETESELF == sysFSDELETESELF {
e.Op |= Remove
}
if mask&sysFSMODIFY == sysFSMODIFY {
e.Op |= Write
}
if mask&sysFSMOVE == sysFSMOVE || mask&sysFSMOVESELF == sysFSMOVESELF || mask&sysFSMOVEDFROM == sysFSMOVEDFROM {
e.Op |= Rename
}
if mask&sysFSATTRIB == sysFSATTRIB {
e.Op |= Chmod
}
return e
}
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
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) {
attr, e := syscall.GetFileAttributes(syscall.StringToUTF16Ptr(pathname))
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) {
h, e := syscall.CreateFile(syscall.StringToUTF16Ptr(path),
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&sysFSONLYDIR != 0 && pathname != dir {
return nil
}
ino, err := getIno(dir)
if err != nil {
return err
}
w.mu.Lock()
watchEntry := w.watches.get(ino)
w.mu.Unlock()
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.mu.Lock()
w.watches.set(ino, watchEntry)
w.mu.Unlock()
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) remWatch(pathname string) error {
dir, err := getDir(pathname)
if err != nil {
return err
}
ino, err := getIno(dir)
if err != nil {
return err
}
w.mu.Lock()
watch := w.watches.get(ino)
w.mu.Unlock()
if watch == nil {
return fmt.Errorf("can't remove non-existent watch for: %s", pathname)
}
if pathname == dir {
w.sendEvent(watch.path, watch.mask&sysFSIGNORED)
watch.mask = 0
} else {
name := filepath.Base(pathname)
w.sendEvent(filepath.Join(watch.path, name), watch.names[name]&sysFSIGNORED)
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(filepath.Join(watch.path, name), mask&sysFSIGNORED)
}
delete(watch.names, name)
}
if watch.mask != 0 {
if watch.mask&provisional == 0 {
w.sendEvent(watch.path, watch.mask&sysFSIGNORED)
}
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.Errors <- 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.Errors <- os.NewSyscallError("CloseHandle", e)
}
w.mu.Lock()
delete(w.watches[watch.ino.volume], watch.ino.index)
w.mu.Unlock()
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&sysFSDELETESELF) {
if watch.mask&sysFSONESHOT != 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 Events 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:
w.mu.Lock()
var indexes []indexMap
for _, index := range w.watches {
indexes = append(indexes, index)
}
w.mu.Unlock()
for _, index := range indexes {
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.Events)
close(w.Errors)
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.remWatch(in.path)
}
default:
}
continue
}
switch e {
case syscall.ERROR_MORE_DATA:
if watch == nil {
w.Errors <- errors.New("ERROR_MORE_DATA has unexpectedly null lpOverlapped buffer")
} else {
// The i/o succeeded but the buffer is full.
// In theory we should be building up a full packet.
// In practice we can get away with just carrying on.
n = uint32(unsafe.Sizeof(watch.buf))
}
case syscall.ERROR_ACCESS_DENIED:
// Watched directory was probably removed
w.sendEvent(watch.path, watch.mask&sysFSDELETESELF)
w.deleteWatch(watch)
w.startRead(watch)
continue
case syscall.ERROR_OPERATION_ABORTED:
// CancelIo was called on this handle
continue
default:
w.Errors <- os.NewSyscallError("GetQueuedCompletionPort", e)
continue
case nil:
}
var offset uint32
for {
if n == 0 {
w.Events <- newEvent("", sysFSQOVERFLOW)
w.Errors <- 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 := filepath.Join(watch.path, name)
var mask uint64
switch raw.Action {
case syscall.FILE_ACTION_REMOVED:
mask = sysFSDELETESELF
case syscall.FILE_ACTION_MODIFIED:
mask = sysFSMODIFY
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 = sysFSMOVESELF
}
}
sendNameEvent := func() {
if w.sendEvent(fullname, watch.names[name]&mask) {
if watch.names[name]&sysFSONESHOT != 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]&sysFSIGNORED)
delete(watch.names, name)
}
if w.sendEvent(fullname, watch.mask&toFSnotifyFlags(raw.Action)) {
if watch.mask&sysFSONESHOT != 0 {
watch.mask = 0
}
}
if raw.Action == syscall.FILE_ACTION_RENAMED_NEW_NAME {
fullname = filepath.Join(watch.path, watch.rename)
sendNameEvent()
}
// Move to the next event in the buffer
if raw.NextEntryOffset == 0 {
break
}
offset += raw.NextEntryOffset
// Error!
if offset >= n {
w.Errors <- errors.New("Windows system assumed buffer larger than it is, events have likely been missed.")
break
}
}
if err := w.startRead(watch); err != nil {
w.Errors <- err
}
}
}
func (w *Watcher) sendEvent(name string, mask uint64) bool {
if mask == 0 {
return false
}
event := newEvent(name, uint32(mask))
select {
case ch := <-w.quit:
w.quit <- ch
case w.Events <- event:
}
return true
}
func toWindowsFlags(mask uint64) uint32 {
var m uint32
if mask&sysFSACCESS != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_LAST_ACCESS
}
if mask&sysFSMODIFY != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_LAST_WRITE
}
if mask&sysFSATTRIB != 0 {
m |= syscall.FILE_NOTIFY_CHANGE_ATTRIBUTES
}
if mask&(sysFSMOVE|sysFSCREATE|sysFSDELETE) != 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 sysFSCREATE
case syscall.FILE_ACTION_REMOVED:
return sysFSDELETE
case syscall.FILE_ACTION_MODIFIED:
return sysFSMODIFY
case syscall.FILE_ACTION_RENAMED_OLD_NAME:
return sysFSMOVEDFROM
case syscall.FILE_ACTION_RENAMED_NEW_NAME:
return sysFSMOVEDTO
}
return 0
}