syncthing/internal/scanner/walk.go
2014-09-28 14:23:07 +01:00

216 lines
5.4 KiB
Go

// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
// All rights reserved. Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package scanner
import (
"errors"
"os"
"path/filepath"
"runtime"
"code.google.com/p/go.text/unicode/norm"
"github.com/syncthing/syncthing/internal/ignore"
"github.com/syncthing/syncthing/internal/lamport"
"github.com/syncthing/syncthing/internal/protocol"
)
type Walker struct {
// Dir is the base directory for the walk
Dir string
// Limit walking to this path within Dir, or no limit if Sub is blank
Sub string
// BlockSize controls the size of the block used when hashing.
BlockSize int
// List of patterns to ignore
Ignores ignore.Patterns
// If TempNamer is not nil, it is used to ignore tempory files when walking.
TempNamer TempNamer
// If CurrentFiler is not nil, it is queried for the current file before rescanning.
CurrentFiler CurrentFiler
// If IgnorePerms is true, changes to permission bits will not be
// detected. Scanned files will get zero permission bits and the
// NoPermissionBits flag set.
IgnorePerms bool
}
type TempNamer interface {
// Temporary returns a temporary name for the filed referred to by filepath.
TempName(path string) string
// IsTemporary returns true if path refers to the name of temporary file.
IsTemporary(path string) bool
}
type CurrentFiler interface {
// CurrentFile returns the file as seen at last scan.
CurrentFile(name string) protocol.FileInfo
}
// Walk returns the list of files found in the local folder by scanning the
// file system. Files are blockwise hashed.
func (w *Walker) Walk() (chan protocol.FileInfo, error) {
if debug {
l.Debugln("Walk", w.Dir, w.Sub, w.BlockSize, w.Ignores)
}
err := checkDir(w.Dir)
if err != nil {
return nil, err
}
files := make(chan protocol.FileInfo)
hashedFiles := make(chan protocol.FileInfo)
newParallelHasher(w.Dir, w.BlockSize, runtime.NumCPU(), hashedFiles, files)
go func() {
hashFiles := w.walkAndHashFiles(files)
filepath.Walk(filepath.Join(w.Dir, w.Sub), hashFiles)
close(files)
}()
return hashedFiles, nil
}
// CleanTempFiles removes all files that match the temporary filename pattern.
func (w *Walker) CleanTempFiles() {
filepath.Walk(w.Dir, w.cleanTempFile)
}
func (w *Walker) walkAndHashFiles(fchan chan protocol.FileInfo) filepath.WalkFunc {
return func(p string, info os.FileInfo, err error) error {
if err != nil {
if debug {
l.Debugln("error:", p, info, err)
}
return nil
}
rn, err := filepath.Rel(w.Dir, p)
if err != nil {
if debug {
l.Debugln("rel error:", p, err)
}
return nil
}
if rn == "." {
return nil
}
if w.TempNamer != nil && w.TempNamer.IsTemporary(rn) {
// A temporary file
if debug {
l.Debugln("temporary:", rn)
}
return nil
}
if sn := filepath.Base(rn); sn == ".stignore" || sn == ".stversions" || w.Ignores.Match(rn) {
// An ignored file
if debug {
l.Debugln("ignored:", rn)
}
if info.IsDir() {
return filepath.SkipDir
}
return nil
}
if (runtime.GOOS == "linux" || runtime.GOOS == "windows") && !norm.NFC.IsNormalString(rn) {
l.Warnf("File %q contains non-NFC UTF-8 sequences and cannot be synced. Consider renaming.", rn)
return nil
}
if info.Mode().IsDir() {
if w.CurrentFiler != nil {
cf := w.CurrentFiler.CurrentFile(rn)
permUnchanged := w.IgnorePerms || !protocol.HasPermissionBits(cf.Flags) || PermsEqual(cf.Flags, uint32(info.Mode()))
if !protocol.IsDeleted(cf.Flags) && protocol.IsDirectory(cf.Flags) && permUnchanged {
return nil
}
}
var flags uint32 = protocol.FlagDirectory
if w.IgnorePerms {
flags |= protocol.FlagNoPermBits | 0777
} else {
flags |= uint32(info.Mode() & os.ModePerm)
}
f := protocol.FileInfo{
Name: rn,
Version: lamport.Default.Tick(0),
Flags: flags,
Modified: info.ModTime().Unix(),
}
if debug {
l.Debugln("dir:", f)
}
fchan <- f
return nil
}
if info.Mode().IsRegular() {
if w.CurrentFiler != nil {
cf := w.CurrentFiler.CurrentFile(rn)
permUnchanged := w.IgnorePerms || !protocol.HasPermissionBits(cf.Flags) || PermsEqual(cf.Flags, uint32(info.Mode()))
if !protocol.IsDeleted(cf.Flags) && cf.Modified == info.ModTime().Unix() && permUnchanged {
return nil
}
if debug {
l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
}
}
var flags = uint32(info.Mode() & os.ModePerm)
if w.IgnorePerms {
flags = protocol.FlagNoPermBits | 0666
}
fchan <- protocol.FileInfo{
Name: rn,
Version: lamport.Default.Tick(0),
Flags: flags,
Modified: info.ModTime().Unix(),
}
}
return nil
}
}
func (w *Walker) cleanTempFile(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.Mode()&os.ModeType == 0 && w.TempNamer.IsTemporary(path) {
os.Remove(path)
}
return nil
}
func checkDir(dir string) error {
if info, err := os.Lstat(dir); err != nil {
return err
} else if !info.IsDir() {
return errors.New(dir + ": not a directory")
} else if debug {
l.Debugln("checkDir", dir, info)
}
return nil
}
func PermsEqual(a, b uint32) bool {
switch runtime.GOOS {
case "windows":
// There is only writeable and read only, represented for user, group
// and other equally. We only compare against user.
return a&0600 == b&0600
default:
// All bits count
return a&0777 == b&0777
}
}