syncthing/scanner/walk.go
2014-07-29 11:53:45 +02:00

308 lines
7.8 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 (
"bytes"
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strings"
"time"
"code.google.com/p/go.text/unicode/norm"
"github.com/calmh/syncthing/lamport"
"github.com/calmh/syncthing/protocol"
)
type Walker struct {
// Dir is the base directory for the walk
Dir 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
// If CurrentFiler is not nil, it is queried for the current file before rescanning.
CurrentFiler CurrentFiler
// If Suppressor is not nil, it is queried for supression of modified files.
// Suppressed files will be returned with empty metadata and the Suppressed flag set.
// Requires CurrentFiler to be set.
Suppressor Suppressor
// 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 Suppressor interface {
// Supress returns true if the update to the named file should be ignored.
Suppress(name string, fi os.FileInfo) (bool, 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 repository by scanning the
// file system. Files are blockwise hashed.
func (w *Walker) Walk() (files chan protocol.FileInfo, ignore map[string][]string, err error) {
if debug {
l.Debugln("Walk", w.Dir, w.BlockSize, w.IgnoreFile)
}
err = checkDir(w.Dir)
if err != nil {
return
}
ignore = make(map[string][]string)
files = make(chan protocol.FileInfo)
hashFiles := w.walkAndHashFiles(files, ignore)
go func() {
filepath.Walk(w.Dir, w.loadIgnoreFiles(w.Dir, ignore))
filepath.Walk(w.Dir, hashFiles)
close(files)
}()
return
}
// 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, ign map[string][]string) filepath.WalkFunc {
return func(p string, info os.FileInfo, err error) error {
if err != nil {
return nil
}
rn, err := filepath.Rel(dir, p)
if err != nil {
return nil
}
if pn, sn := filepath.Split(rn); sn == w.IgnoreFile {
pn := filepath.Clean(pn)
bs, _ := ioutil.ReadFile(p)
lines := bytes.Split(bs, []byte("\n"))
var patterns []string
for _, line := range lines {
lineStr := strings.TrimSpace(string(line))
if len(lineStr) > 0 {
patterns = append(patterns, lineStr)
}
}
ign[pn] = patterns
}
return nil
}
}
func (w *Walker) walkAndHashFiles(fchan chan protocol.FileInfo, ign map[string][]string) 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 == w.IgnoreFile || sn == ".stversions" || w.ignoreFile(ign, 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 w.Suppressor != nil {
if cur, prev := w.Suppressor.Suppress(rn, info); cur && !prev {
l.Infof("Changes to %q are being temporarily suppressed because it changes too frequently.", p)
cf.Flags |= protocol.FlagInvalid
cf.Version = lamport.Default.Tick(cf.Version)
cf.LocalVersion = 0
if debug {
l.Debugln("suppressed:", cf)
}
fchan <- cf
return nil
} else if prev && !cur {
l.Infof("Changes to %q are no longer suppressed.", p)
}
}
if debug {
l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
}
}
fd, err := os.Open(p)
if err != nil {
if debug {
l.Debugln("open:", p, err)
}
return nil
}
defer fd.Close()
t0 := time.Now()
blocks, err := Blocks(fd, w.BlockSize)
if err != nil {
if debug {
l.Debugln("hash error:", rn, err)
}
return nil
}
if debug {
t1 := time.Now()
l.Debugln("hashed:", rn, ";", len(blocks), "blocks;", info.Size(), "bytes;", int(float64(info.Size())/1024/t1.Sub(t0).Seconds()), "KB/s")
}
var flags = uint32(info.Mode() & os.ModePerm)
if w.IgnorePerms {
flags = protocol.FlagNoPermBits | 0666
}
f := protocol.FileInfo{
Name: rn,
Version: lamport.Default.Tick(0),
Flags: flags,
Modified: info.ModTime().Unix(),
Blocks: blocks,
}
fchan <- f
}
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 map[string][]string, file string) bool {
first, last := filepath.Split(file)
for prefix, pats := range patterns {
if prefix == "." || prefix == first || strings.HasPrefix(first, fmt.Sprintf("%s%c", prefix, os.PathSeparator)) {
for _, pattern := range pats {
if match, _ := filepath.Match(pattern, last); match {
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
}
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
}
}