599 lines
15 KiB
Go
599 lines
15 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build windows
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package fsnotify
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import (
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"errors"
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"fmt"
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"os"
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"path/filepath"
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"runtime"
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"sync"
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"syscall"
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"unsafe"
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)
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const (
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// Options for AddWatch
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sys_FS_ONESHOT = 0x80000000
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sys_FS_ONLYDIR = 0x1000000
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// Events
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sys_FS_ACCESS = 0x1
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sys_FS_ALL_EVENTS = 0xfff
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sys_FS_ATTRIB = 0x4
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sys_FS_CLOSE = 0x18
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sys_FS_CREATE = 0x100
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sys_FS_DELETE = 0x200
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sys_FS_DELETE_SELF = 0x400
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sys_FS_MODIFY = 0x2
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sys_FS_MOVE = 0xc0
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sys_FS_MOVED_FROM = 0x40
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sys_FS_MOVED_TO = 0x80
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sys_FS_MOVE_SELF = 0x800
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// Special events
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sys_FS_IGNORED = 0x8000
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sys_FS_Q_OVERFLOW = 0x4000
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)
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const (
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// TODO(nj): Use syscall.ERROR_MORE_DATA from ztypes_windows in Go 1.3+
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sys_ERROR_MORE_DATA syscall.Errno = 234
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)
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// Event is the type of the notification messages
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// received on the watcher's Event channel.
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type FileEvent struct {
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mask uint32 // Mask of events
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cookie uint32 // Unique cookie associating related events (for rename)
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Name string // File name (optional)
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}
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// IsCreate reports whether the FileEvent was triggered by a creation
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func (e *FileEvent) IsCreate() bool { return (e.mask & sys_FS_CREATE) == sys_FS_CREATE }
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// IsDelete reports whether the FileEvent was triggered by a delete
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func (e *FileEvent) IsDelete() bool {
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return ((e.mask&sys_FS_DELETE) == sys_FS_DELETE || (e.mask&sys_FS_DELETE_SELF) == sys_FS_DELETE_SELF)
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}
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// IsModify reports whether the FileEvent was triggered by a file modification or attribute change
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func (e *FileEvent) IsModify() bool {
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return ((e.mask&sys_FS_MODIFY) == sys_FS_MODIFY || (e.mask&sys_FS_ATTRIB) == sys_FS_ATTRIB)
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}
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// IsRename reports whether the FileEvent was triggered by a change name
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func (e *FileEvent) IsRename() bool {
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return ((e.mask&sys_FS_MOVE) == sys_FS_MOVE || (e.mask&sys_FS_MOVE_SELF) == sys_FS_MOVE_SELF || (e.mask&sys_FS_MOVED_FROM) == sys_FS_MOVED_FROM || (e.mask&sys_FS_MOVED_TO) == sys_FS_MOVED_TO)
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}
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// IsAttrib reports whether the FileEvent was triggered by a change in the file metadata.
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func (e *FileEvent) IsAttrib() bool {
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return (e.mask & sys_FS_ATTRIB) == sys_FS_ATTRIB
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}
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const (
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opAddWatch = iota
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opRemoveWatch
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)
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const (
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provisional uint64 = 1 << (32 + iota)
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)
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type input struct {
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op int
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path string
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flags uint32
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reply chan error
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}
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type inode struct {
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handle syscall.Handle
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volume uint32
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index uint64
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}
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type watch struct {
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ov syscall.Overlapped
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ino *inode // i-number
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path string // Directory path
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mask uint64 // Directory itself is being watched with these notify flags
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names map[string]uint64 // Map of names being watched and their notify flags
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rename string // Remembers the old name while renaming a file
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buf [4096]byte
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}
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type indexMap map[uint64]*watch
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type watchMap map[uint32]indexMap
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// A Watcher waits for and receives event notifications
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// for a specific set of files and directories.
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type Watcher struct {
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mu sync.Mutex // Map access
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port syscall.Handle // Handle to completion port
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watches watchMap // Map of watches (key: i-number)
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fsnFlags map[string]uint32 // Map of watched files to flags used for filter
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fsnmut sync.Mutex // Protects access to fsnFlags.
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input chan *input // Inputs to the reader are sent on this channel
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internalEvent chan *FileEvent // Events are queued on this channel
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Event chan *FileEvent // Events are returned on this channel
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Error chan error // Errors are sent on this channel
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isClosed bool // Set to true when Close() is first called
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quit chan chan<- error
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cookie uint32
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}
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// NewWatcher creates and returns a Watcher.
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func NewWatcher() (*Watcher, error) {
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port, e := syscall.CreateIoCompletionPort(syscall.InvalidHandle, 0, 0, 0)
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if e != nil {
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return nil, os.NewSyscallError("CreateIoCompletionPort", e)
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}
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w := &Watcher{
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port: port,
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watches: make(watchMap),
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fsnFlags: make(map[string]uint32),
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input: make(chan *input, 1),
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Event: make(chan *FileEvent, 50),
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internalEvent: make(chan *FileEvent),
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Error: make(chan error),
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quit: make(chan chan<- error, 1),
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}
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go w.readEvents()
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go w.purgeEvents()
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return w, nil
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}
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// Close closes a Watcher.
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// It sends a message to the reader goroutine to quit and removes all watches
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// associated with the watcher.
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func (w *Watcher) Close() error {
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if w.isClosed {
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return nil
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}
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w.isClosed = true
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// Send "quit" message to the reader goroutine
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ch := make(chan error)
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w.quit <- ch
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if err := w.wakeupReader(); err != nil {
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return err
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}
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return <-ch
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}
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// AddWatch adds path to the watched file set.
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func (w *Watcher) AddWatch(path string, flags uint32) error {
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if w.isClosed {
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return errors.New("watcher already closed")
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}
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in := &input{
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op: opAddWatch,
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path: filepath.Clean(path),
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flags: flags,
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reply: make(chan error),
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}
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w.input <- in
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if err := w.wakeupReader(); err != nil {
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return err
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}
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return <-in.reply
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}
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// Watch adds path to the watched file set, watching all events.
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func (w *Watcher) watch(path string) error {
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return w.AddWatch(path, sys_FS_ALL_EVENTS)
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}
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// RemoveWatch removes path from the watched file set.
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func (w *Watcher) removeWatch(path string) error {
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in := &input{
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op: opRemoveWatch,
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path: filepath.Clean(path),
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reply: make(chan error),
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}
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w.input <- in
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if err := w.wakeupReader(); err != nil {
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return err
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}
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return <-in.reply
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}
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func (w *Watcher) wakeupReader() error {
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e := syscall.PostQueuedCompletionStatus(w.port, 0, 0, nil)
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if e != nil {
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return os.NewSyscallError("PostQueuedCompletionStatus", e)
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}
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return nil
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}
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func getDir(pathname string) (dir string, err error) {
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attr, e := syscall.GetFileAttributes(syscall.StringToUTF16Ptr(pathname))
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if e != nil {
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return "", os.NewSyscallError("GetFileAttributes", e)
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}
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if attr&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 {
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dir = pathname
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} else {
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dir, _ = filepath.Split(pathname)
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dir = filepath.Clean(dir)
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}
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return
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}
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func getIno(path string) (ino *inode, err error) {
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h, e := syscall.CreateFile(syscall.StringToUTF16Ptr(path),
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syscall.FILE_LIST_DIRECTORY,
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syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
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nil, syscall.OPEN_EXISTING,
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syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OVERLAPPED, 0)
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if e != nil {
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return nil, os.NewSyscallError("CreateFile", e)
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}
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var fi syscall.ByHandleFileInformation
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if e = syscall.GetFileInformationByHandle(h, &fi); e != nil {
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syscall.CloseHandle(h)
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return nil, os.NewSyscallError("GetFileInformationByHandle", e)
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}
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ino = &inode{
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handle: h,
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volume: fi.VolumeSerialNumber,
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index: uint64(fi.FileIndexHigh)<<32 | uint64(fi.FileIndexLow),
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}
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return ino, nil
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}
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// Must run within the I/O thread.
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func (m watchMap) get(ino *inode) *watch {
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if i := m[ino.volume]; i != nil {
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return i[ino.index]
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}
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return nil
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}
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// Must run within the I/O thread.
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func (m watchMap) set(ino *inode, watch *watch) {
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i := m[ino.volume]
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if i == nil {
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i = make(indexMap)
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m[ino.volume] = i
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}
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i[ino.index] = watch
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}
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// Must run within the I/O thread.
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func (w *Watcher) addWatch(pathname string, flags uint64) error {
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dir, err := getDir(pathname)
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if err != nil {
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return err
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}
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if flags&sys_FS_ONLYDIR != 0 && pathname != dir {
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return nil
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}
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ino, err := getIno(dir)
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if err != nil {
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return err
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}
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w.mu.Lock()
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watchEntry := w.watches.get(ino)
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w.mu.Unlock()
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if watchEntry == nil {
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if _, e := syscall.CreateIoCompletionPort(ino.handle, w.port, 0, 0); e != nil {
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syscall.CloseHandle(ino.handle)
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return os.NewSyscallError("CreateIoCompletionPort", e)
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}
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watchEntry = &watch{
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ino: ino,
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path: dir,
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names: make(map[string]uint64),
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}
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w.mu.Lock()
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w.watches.set(ino, watchEntry)
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w.mu.Unlock()
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flags |= provisional
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} else {
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syscall.CloseHandle(ino.handle)
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}
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if pathname == dir {
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watchEntry.mask |= flags
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} else {
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watchEntry.names[filepath.Base(pathname)] |= flags
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}
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if err = w.startRead(watchEntry); err != nil {
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return err
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}
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if pathname == dir {
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watchEntry.mask &= ^provisional
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} else {
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watchEntry.names[filepath.Base(pathname)] &= ^provisional
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}
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return nil
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}
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// Must run within the I/O thread.
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func (w *Watcher) remWatch(pathname string) error {
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dir, err := getDir(pathname)
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if err != nil {
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return err
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}
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ino, err := getIno(dir)
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if err != nil {
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return err
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}
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w.mu.Lock()
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watch := w.watches.get(ino)
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w.mu.Unlock()
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if watch == nil {
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return fmt.Errorf("can't remove non-existent watch for: %s", pathname)
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}
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if pathname == dir {
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w.sendEvent(watch.path, watch.mask&sys_FS_IGNORED)
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watch.mask = 0
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} else {
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name := filepath.Base(pathname)
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w.sendEvent(watch.path+"\\"+name, watch.names[name]&sys_FS_IGNORED)
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delete(watch.names, name)
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}
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return w.startRead(watch)
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}
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// Must run within the I/O thread.
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func (w *Watcher) deleteWatch(watch *watch) {
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for name, mask := range watch.names {
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if mask&provisional == 0 {
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w.sendEvent(watch.path+"\\"+name, mask&sys_FS_IGNORED)
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}
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delete(watch.names, name)
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}
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if watch.mask != 0 {
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if watch.mask&provisional == 0 {
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w.sendEvent(watch.path, watch.mask&sys_FS_IGNORED)
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}
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watch.mask = 0
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}
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}
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// Must run within the I/O thread.
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func (w *Watcher) startRead(watch *watch) error {
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if e := syscall.CancelIo(watch.ino.handle); e != nil {
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w.Error <- os.NewSyscallError("CancelIo", e)
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w.deleteWatch(watch)
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}
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mask := toWindowsFlags(watch.mask)
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for _, m := range watch.names {
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mask |= toWindowsFlags(m)
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}
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if mask == 0 {
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if e := syscall.CloseHandle(watch.ino.handle); e != nil {
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w.Error <- os.NewSyscallError("CloseHandle", e)
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}
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w.mu.Lock()
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delete(w.watches[watch.ino.volume], watch.ino.index)
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w.mu.Unlock()
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return nil
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}
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e := syscall.ReadDirectoryChanges(watch.ino.handle, &watch.buf[0],
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uint32(unsafe.Sizeof(watch.buf)), false, mask, nil, &watch.ov, 0)
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if e != nil {
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err := os.NewSyscallError("ReadDirectoryChanges", e)
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if e == syscall.ERROR_ACCESS_DENIED && watch.mask&provisional == 0 {
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// Watched directory was probably removed
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if w.sendEvent(watch.path, watch.mask&sys_FS_DELETE_SELF) {
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if watch.mask&sys_FS_ONESHOT != 0 {
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watch.mask = 0
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}
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}
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err = nil
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}
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w.deleteWatch(watch)
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w.startRead(watch)
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return err
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}
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return nil
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}
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// readEvents reads from the I/O completion port, converts the
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// received events into Event objects and sends them via the Event channel.
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// Entry point to the I/O thread.
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func (w *Watcher) readEvents() {
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var (
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n, key uint32
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ov *syscall.Overlapped
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)
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runtime.LockOSThread()
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for {
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e := syscall.GetQueuedCompletionStatus(w.port, &n, &key, &ov, syscall.INFINITE)
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watch := (*watch)(unsafe.Pointer(ov))
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if watch == nil {
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select {
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case ch := <-w.quit:
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w.mu.Lock()
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var indexes []indexMap
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for _, index := range w.watches {
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indexes = append(indexes, index)
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}
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w.mu.Unlock()
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for _, index := range indexes {
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for _, watch := range index {
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w.deleteWatch(watch)
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w.startRead(watch)
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}
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}
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var err error
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if e := syscall.CloseHandle(w.port); e != nil {
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err = os.NewSyscallError("CloseHandle", e)
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}
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close(w.internalEvent)
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close(w.Error)
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ch <- err
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return
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case in := <-w.input:
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switch in.op {
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case opAddWatch:
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in.reply <- w.addWatch(in.path, uint64(in.flags))
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case opRemoveWatch:
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in.reply <- w.remWatch(in.path)
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}
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default:
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}
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continue
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}
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switch e {
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case sys_ERROR_MORE_DATA:
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if watch == nil {
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w.Error <- errors.New("ERROR_MORE_DATA has unexpectedly null lpOverlapped buffer")
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} else {
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// The i/o succeeded but the buffer is full.
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// In theory we should be building up a full packet.
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// In practice we can get away with just carrying on.
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n = uint32(unsafe.Sizeof(watch.buf))
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}
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case syscall.ERROR_ACCESS_DENIED:
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// Watched directory was probably removed
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w.sendEvent(watch.path, watch.mask&sys_FS_DELETE_SELF)
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w.deleteWatch(watch)
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w.startRead(watch)
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continue
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case syscall.ERROR_OPERATION_ABORTED:
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// CancelIo was called on this handle
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continue
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default:
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w.Error <- os.NewSyscallError("GetQueuedCompletionPort", e)
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continue
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case nil:
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}
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var offset uint32
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for {
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if n == 0 {
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w.internalEvent <- &FileEvent{mask: sys_FS_Q_OVERFLOW}
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w.Error <- errors.New("short read in readEvents()")
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break
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}
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// Point "raw" to the event in the buffer
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raw := (*syscall.FileNotifyInformation)(unsafe.Pointer(&watch.buf[offset]))
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buf := (*[syscall.MAX_PATH]uint16)(unsafe.Pointer(&raw.FileName))
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name := syscall.UTF16ToString(buf[:raw.FileNameLength/2])
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fullname := watch.path + "\\" + name
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var mask uint64
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switch raw.Action {
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case syscall.FILE_ACTION_REMOVED:
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mask = sys_FS_DELETE_SELF
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case syscall.FILE_ACTION_MODIFIED:
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mask = sys_FS_MODIFY
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case syscall.FILE_ACTION_RENAMED_OLD_NAME:
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watch.rename = name
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case syscall.FILE_ACTION_RENAMED_NEW_NAME:
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if watch.names[watch.rename] != 0 {
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watch.names[name] |= watch.names[watch.rename]
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delete(watch.names, watch.rename)
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mask = sys_FS_MOVE_SELF
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}
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}
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sendNameEvent := func() {
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if w.sendEvent(fullname, watch.names[name]&mask) {
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if watch.names[name]&sys_FS_ONESHOT != 0 {
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delete(watch.names, name)
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}
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}
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}
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if raw.Action != syscall.FILE_ACTION_RENAMED_NEW_NAME {
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sendNameEvent()
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}
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if raw.Action == syscall.FILE_ACTION_REMOVED {
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w.sendEvent(fullname, watch.names[name]&sys_FS_IGNORED)
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delete(watch.names, name)
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}
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if w.sendEvent(fullname, watch.mask&toFSnotifyFlags(raw.Action)) {
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if watch.mask&sys_FS_ONESHOT != 0 {
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watch.mask = 0
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}
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}
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if raw.Action == syscall.FILE_ACTION_RENAMED_NEW_NAME {
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fullname = watch.path + "\\" + watch.rename
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sendNameEvent()
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}
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// Move to the next event in the buffer
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if raw.NextEntryOffset == 0 {
|
|
break
|
|
}
|
|
offset += raw.NextEntryOffset
|
|
|
|
// Error!
|
|
if offset >= n {
|
|
w.Error <- errors.New("Windows system assumed buffer larger than it is, events have likely been missed.")
|
|
break
|
|
}
|
|
}
|
|
|
|
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 := &FileEvent{mask: uint32(mask), Name: name}
|
|
if mask&sys_FS_MOVE != 0 {
|
|
if mask&sys_FS_MOVED_FROM != 0 {
|
|
w.cookie++
|
|
}
|
|
event.cookie = w.cookie
|
|
}
|
|
select {
|
|
case ch := <-w.quit:
|
|
w.quit <- ch
|
|
case w.Event <- event:
|
|
}
|
|
return true
|
|
}
|
|
|
|
func toWindowsFlags(mask uint64) uint32 {
|
|
var m uint32
|
|
if mask&sys_FS_ACCESS != 0 {
|
|
m |= syscall.FILE_NOTIFY_CHANGE_LAST_ACCESS
|
|
}
|
|
if mask&sys_FS_MODIFY != 0 {
|
|
m |= syscall.FILE_NOTIFY_CHANGE_LAST_WRITE
|
|
}
|
|
if mask&sys_FS_ATTRIB != 0 {
|
|
m |= syscall.FILE_NOTIFY_CHANGE_ATTRIBUTES
|
|
}
|
|
if mask&(sys_FS_MOVE|sys_FS_CREATE|sys_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 sys_FS_CREATE
|
|
case syscall.FILE_ACTION_REMOVED:
|
|
return sys_FS_DELETE
|
|
case syscall.FILE_ACTION_MODIFIED:
|
|
return sys_FS_MODIFY
|
|
case syscall.FILE_ACTION_RENAMED_OLD_NAME:
|
|
return sys_FS_MOVED_FROM
|
|
case syscall.FILE_ACTION_RENAMED_NEW_NAME:
|
|
return sys_FS_MOVED_TO
|
|
}
|
|
return 0
|
|
}
|