syncthing/scanner/walk.go

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// 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.
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package scanner
import (
"bufio"
"errors"
"io"
"os"
"path"
"path/filepath"
"regexp"
"runtime"
"strings"
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"code.google.com/p/go.text/unicode/norm"
"github.com/syncthing/syncthing/fnmatch"
"github.com/syncthing/syncthing/lamport"
"github.com/syncthing/syncthing/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
// If IgnoreFile is not empty, it is the name used for the file that holds ignore patterns.
IgnoreFile string
// If TempNamer is not nil, it is used to ignore tempory files when walking.
TempNamer TempNamer
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// If CurrentFiler is not nil, it is queried for the current file before rescanning.
CurrentFiler CurrentFiler
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// If IgnorePerms is true, changes to permission bits will not be
// detected. Scanned files will get zero permission bits and the
// NoPermissionBits flag set.
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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
}
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type CurrentFiler interface {
// CurrentFile returns the file as seen at last scan.
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CurrentFile(name string) protocol.FileInfo
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}
// Walk returns the list of files found in the local repository 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.IgnoreFile)
}
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err := checkDir(w.Dir)
if err != nil {
return nil, err
}
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files := make(chan protocol.FileInfo)
hashedFiles := make(chan protocol.FileInfo)
newParallelHasher(w.Dir, w.BlockSize, runtime.NumCPU(), hashedFiles, files)
var ignores []*regexp.Regexp
go func() {
filepath.Walk(w.Dir, w.loadIgnoreFiles(w.Dir, &ignores))
hashFiles := w.walkAndHashFiles(files, ignores)
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) loadIgnoreFiles(dir string, ignores *[]*regexp.Regexp) filepath.WalkFunc {
return func(p string, info os.FileInfo, err error) error {
if err != nil {
return nil
}
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rn, err := filepath.Rel(dir, p)
if err != nil {
return nil
}
if pn, sn := filepath.Split(rn); sn == w.IgnoreFile {
pn := filepath.Clean(pn)
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filesSeen := make(map[string]map[string]bool)
dirIgnores := loadIgnoreFile(p, pn, filesSeen)
*ignores = append(*ignores, dirIgnores...)
}
return nil
}
}
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func loadIgnoreFile(ignFile, base string, filesSeen map[string]map[string]bool) []*regexp.Regexp {
fd, err := os.Open(ignFile)
if err != nil {
return nil
}
defer fd.Close()
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return parseIgnoreFile(fd, base, ignFile, filesSeen)
}
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func parseIgnoreFile(fd io.Reader, base, currentFile string, filesSeen map[string]map[string]bool) []*regexp.Regexp {
var exps []*regexp.Regexp
scanner := bufio.NewScanner(fd)
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
if line == "" {
continue
}
if strings.HasPrefix(line, "/") {
// Pattern is rooted in the current dir only
exp, err := fnmatch.Convert(path.Join(base, line[1:]), fnmatch.FNM_PATHNAME)
if err != nil {
l.Warnf("Invalid pattern %q in ignore file", line)
continue
}
exps = append(exps, exp)
} else if strings.HasPrefix(line, "**/") {
// Add the pattern as is, and without **/ so it matches in current dir
exp, err := fnmatch.Convert(line, fnmatch.FNM_PATHNAME)
if err != nil {
l.Warnf("Invalid pattern %q in ignore file", line)
continue
}
exps = append(exps, exp)
exp, err = fnmatch.Convert(path.Join(base, line[3:]), fnmatch.FNM_PATHNAME)
if err != nil {
l.Warnf("Invalid pattern %q in ignore file", line)
continue
}
exps = append(exps, exp)
} else if strings.HasPrefix(line, "#include ") {
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includeFile := filepath.Join(filepath.Dir(currentFile), strings.Replace(line, "#include ", "", 1))
if _, err := os.Stat(includeFile); os.IsNotExist(err) {
l.Infoln("Could not open ignore include file", includeFile)
} else {
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seen := false
if seenByCurrent, ok := filesSeen[currentFile]; ok {
_, seen = seenByCurrent[includeFile]
}
if seen {
l.Warnf("Recursion detected while including %s from %s", includeFile, currentFile)
} else {
if filesSeen[currentFile] == nil {
filesSeen[currentFile] = make(map[string]bool)
}
filesSeen[currentFile][includeFile] = true
includes := loadIgnoreFile(includeFile, base, filesSeen)
exps = append(exps, includes...)
}
}
} else {
// Path name or pattern, add it so it matches files both in
// current directory and subdirs.
exp, err := fnmatch.Convert(path.Join(base, line), fnmatch.FNM_PATHNAME)
if err != nil {
l.Warnf("Invalid pattern %q in ignore file", line)
continue
}
exps = append(exps, exp)
exp, err = fnmatch.Convert(path.Join(base, "**", line), fnmatch.FNM_PATHNAME)
if err != nil {
l.Warnf("Invalid pattern %q in ignore file", line)
continue
}
exps = append(exps, exp)
}
}
return exps
}
func (w *Walker) walkAndHashFiles(fchan chan protocol.FileInfo, ignores []*regexp.Regexp) filepath.WalkFunc {
return func(p string, info os.FileInfo, err error) error {
if err != nil {
if debug {
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l.Debugln("error:", p, info, err)
}
return nil
}
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rn, err := filepath.Rel(w.Dir, p)
if err != nil {
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if debug {
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l.Debugln("rel error:", p, err)
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}
return nil
}
if rn == "." {
return nil
}
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if w.TempNamer != nil && w.TempNamer.IsTemporary(rn) {
// A temporary file
if debug {
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l.Debugln("temporary:", rn)
}
return nil
}
if sn := filepath.Base(rn); sn == w.IgnoreFile || sn == ".stversions" || w.ignoreFile(ignores, rn) {
// An ignored file
if debug {
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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)
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permUnchanged := w.IgnorePerms || !protocol.HasPermissionBits(cf.Flags) || PermsEqual(cf.Flags, uint32(info.Mode()))
if !protocol.IsDeleted(cf.Flags) && protocol.IsDirectory(cf.Flags) && permUnchanged {
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return nil
}
}
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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
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return nil
}
if info.Mode().IsRegular() {
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if w.CurrentFiler != nil {
cf := w.CurrentFiler.CurrentFile(rn)
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permUnchanged := w.IgnorePerms || !protocol.HasPermissionBits(cf.Flags) || PermsEqual(cf.Flags, uint32(info.Mode()))
if !protocol.IsDeleted(cf.Flags) && cf.Modified == info.ModTime().Unix() && permUnchanged {
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return nil
}
if debug {
l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
}
}
var flags = uint32(info.Mode() & os.ModePerm)
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if w.IgnorePerms {
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flags = protocol.FlagNoPermBits | 0666
}
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fchan <- protocol.FileInfo{
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Name: rn,
Version: lamport.Default.Tick(0),
Flags: flags,
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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 (w *Walker) ignoreFile(patterns []*regexp.Regexp, file string) bool {
for _, pattern := range patterns {
if pattern.MatchString(file) {
if debug {
l.Debugf("%q matches %v", file, pattern)
}
return true
}
}
return false
}
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
}
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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
}
}