syncthing/scanner/walk.go
2014-03-16 08:14:55 +01:00

263 lines
6.2 KiB
Go

package scanner
import (
"bytes"
"io/ioutil"
"log"
"os"
"path"
"path/filepath"
"strings"
"time"
)
type Walker struct {
// Dir is the base directory for the walk
Dir string
// If FollowSymlinks is true, symbolic links directly under Dir will be followed.
// Symbolic links at deeper levels are never followed regardless of this flag.
FollowSymlinks bool
// 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
suppressed map[string]bool // file name -> suppression status
}
type TempNamer interface {
// Temporary returns a temporary name for the filed referred to by path.
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
}
type CurrentFiler interface {
// CurrentFile returns the file as seen at last scan.
CurrentFile(name string) File
}
// 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 []File, ignore map[string][]string) {
w.lazyInit()
if debug {
dlog.Println("Walk", w.Dir, w.FollowSymlinks, w.BlockSize, w.IgnoreFile)
}
t0 := time.Now()
ignore = make(map[string][]string)
hashFiles := w.walkAndHashFiles(&files, ignore)
filepath.Walk(w.Dir, w.loadIgnoreFiles(w.Dir, ignore))
filepath.Walk(w.Dir, hashFiles)
if w.FollowSymlinks {
d, err := os.Open(w.Dir)
if err != nil {
return
}
defer d.Close()
fis, err := d.Readdir(-1)
if err != nil {
return
}
for _, info := range fis {
if info.Mode()&os.ModeSymlink != 0 {
dir := path.Join(w.Dir, info.Name()) + "/"
filepath.Walk(dir, w.loadIgnoreFiles(dir, ignore))
filepath.Walk(dir, hashFiles)
}
}
}
if debug {
t1 := time.Now()
d := t1.Sub(t0).Seconds()
dlog.Printf("Walk in %.02f ms, %.0f files/s", d*1000, float64(len(files))/d)
}
return
}
// CleanTempFiles removes all files that match the temporary filename pattern.
func (w *Walker) CleanTempFiles() {
filepath.Walk(w.Dir, w.cleanTempFile)
}
func (w *Walker) lazyInit() {
if w.suppressed == nil {
w.suppressed = make(map[string]bool)
}
}
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 := path.Split(rn); sn == w.IgnoreFile {
pn := strings.Trim(pn, "/")
bs, _ := ioutil.ReadFile(p)
lines := bytes.Split(bs, []byte("\n"))
var patterns []string
for _, line := range lines {
if len(line) > 0 {
patterns = append(patterns, string(line))
}
}
ign[pn] = patterns
}
return nil
}
}
func (w *Walker) walkAndHashFiles(res *[]File, ign map[string][]string) filepath.WalkFunc {
return func(p string, info os.FileInfo, err error) error {
if err != nil {
if debug {
dlog.Println("error:", p, info, err)
}
return nil
}
rn, err := filepath.Rel(w.Dir, p)
if err != nil {
if debug {
dlog.Println("rel error:", p, err)
}
return nil
}
if w.TempNamer != nil && w.TempNamer.IsTemporary(rn) {
if debug {
dlog.Println("temporary:", rn)
}
return nil
}
if _, sn := path.Split(rn); sn == w.IgnoreFile {
if debug {
dlog.Println("ignorefile:", rn)
}
return nil
}
if rn != "." && w.ignoreFile(ign, rn) {
if debug {
dlog.Println("ignored:", rn)
}
if info.IsDir() {
return filepath.SkipDir
}
return nil
}
if info.Mode()&os.ModeType == 0 {
if w.CurrentFiler != nil {
cf := w.CurrentFiler.CurrentFile(rn)
if cf.Modified == info.ModTime().Unix() {
if debug {
dlog.Println("unchanged:", rn)
}
*res = append(*res, cf)
return nil
}
if w.Suppressor != nil && w.Suppressor.Suppress(rn, info) {
if debug {
dlog.Println("suppressed:", rn)
}
if !w.suppressed[rn] {
w.suppressed[rn] = true
log.Printf("INFO: Changes to %q are being temporarily suppressed because it changes too frequently.", p)
}
cf.Suppressed = true
*res = append(*res, cf)
} else if w.suppressed[rn] {
log.Printf("INFO: Changes to %q are no longer suppressed.", p)
delete(w.suppressed, rn)
}
}
fd, err := os.Open(p)
if err != nil {
if debug {
dlog.Println("open:", p, err)
}
return nil
}
defer fd.Close()
t0 := time.Now()
blocks, err := Blocks(fd, w.BlockSize)
if err != nil {
if debug {
dlog.Println("hash error:", rn, err)
}
return nil
}
if debug {
t1 := time.Now()
dlog.Println("hashed:", rn, ";", len(blocks), "blocks;", info.Size(), "bytes;", int(float64(info.Size())/1024/t1.Sub(t0).Seconds()), "KB/s")
}
f := File{
Name: rn,
Size: info.Size(),
Flags: uint32(info.Mode()),
Modified: info.ModTime().Unix(),
Blocks: blocks,
}
*res = append(*res, 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 := path.Split(file)
for prefix, pats := range patterns {
if len(prefix) == 0 || prefix == first || strings.HasPrefix(first, prefix+"/") {
for _, pattern := range pats {
if match, _ := path.Match(pattern, last); match {
return true
}
}
}
}
return false
}