Refactor out file scanner into separate package
This commit is contained in:
Jakob Borg
259
scanner/walk.go
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259
scanner/walk.go
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@@ -0,0 +1,259 @@
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package scanner
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import (
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"bytes"
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"io/ioutil"
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"log"
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"os"
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"path"
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"path/filepath"
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"strings"
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"time"
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"github.com/calmh/syncthing/protocol"
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)
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type Walker struct {
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// Dir is the base directory for the walk
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Dir string
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// If FollowSymlinks is true, symbolic links directly under Dir will be followed.
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// Symbolic links at deeper levels are never followed regardless of this flag.
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FollowSymlinks bool
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// BlockSize controls the size of the block used when hashing.
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BlockSize int
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// If IgnoreFile is not empty, it is the name used for the file that holds ignore patterns.
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IgnoreFile string
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// If TempNamer is not nil, it is used to ignore tempory files when walking.
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TempNamer TempNamer
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// If Suppressor is not nil, it is queried for supression of modified files.
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Suppressor Suppressor
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previous map[string]File // file name -> last seen file state
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suppressed map[string]bool // file name -> suppression status
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}
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type TempNamer interface {
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// Temporary returns a temporary name for the filed referred to by path.
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TempName(path string) string
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// IsTemporary returns true if path refers to the name of temporary file.
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IsTemporary(path string) bool
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}
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type Suppressor interface {
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// Supress returns true if the update to the named file should be ignored.
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Suppress(name string, fi os.FileInfo) bool
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}
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// Walk returns the list of files found in the local repository by scanning the
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// file system. Files are blockwise hashed.
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func (w *Walker) Walk() (files []File, ignore map[string][]string) {
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w.lazyInit()
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if debug {
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dlog.Println("Walk", w.Dir, w.FollowSymlinks, w.BlockSize, w.IgnoreFile)
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}
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t0 := time.Now()
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ignore = make(map[string][]string)
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hashFiles := w.walkAndHashFiles(&files, ignore)
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filepath.Walk(w.Dir, w.loadIgnoreFiles(w.Dir, ignore))
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filepath.Walk(w.Dir, hashFiles)
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if w.FollowSymlinks {
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d, err := os.Open(w.Dir)
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if err != nil {
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return
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}
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defer d.Close()
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fis, err := d.Readdir(-1)
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if err != nil {
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return
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}
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for _, info := range fis {
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if info.Mode()&os.ModeSymlink != 0 {
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dir := path.Join(w.Dir, info.Name()) + "/"
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filepath.Walk(dir, w.loadIgnoreFiles(dir, ignore))
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filepath.Walk(dir, hashFiles)
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}
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}
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}
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if debug {
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t1 := time.Now()
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d := t1.Sub(t0).Seconds()
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dlog.Printf("Walk in %.02f ms, %.0f files/s", d*1000, float64(len(files))/d)
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}
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return
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}
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// CleanTempFiles removes all files that match the temporary filename pattern.
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func (w *Walker) CleanTempFiles() {
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filepath.Walk(w.Dir, w.cleanTempFile)
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}
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func (w *Walker) lazyInit() {
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if w.previous == nil {
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w.previous = make(map[string]File)
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w.suppressed = make(map[string]bool)
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}
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}
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func (w *Walker) loadIgnoreFiles(dir string, ign map[string][]string) filepath.WalkFunc {
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return func(p string, info os.FileInfo, err error) error {
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if err != nil {
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return nil
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}
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p, err = filepath.Rel(dir, p)
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if err != nil {
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return nil
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}
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if pn, sn := path.Split(p); sn == w.IgnoreFile {
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pn := strings.Trim(pn, "/")
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bs, _ := ioutil.ReadFile(p)
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lines := bytes.Split(bs, []byte("\n"))
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var patterns []string
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for _, line := range lines {
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if len(line) > 0 {
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patterns = append(patterns, string(line))
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}
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}
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ign[pn] = patterns
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}
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return nil
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}
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}
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func (w *Walker) walkAndHashFiles(res *[]File, ign map[string][]string) filepath.WalkFunc {
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return func(p string, info os.FileInfo, err error) error {
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if err != nil {
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if debug {
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dlog.Println("error:", p, info, err)
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}
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return nil
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}
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p, err = filepath.Rel(w.Dir, p)
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if err != nil {
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return nil
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}
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if w.TempNamer != nil && w.TempNamer.IsTemporary(p) {
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if debug {
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dlog.Println("temporary:", p)
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}
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return nil
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}
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if _, sn := path.Split(p); sn == w.IgnoreFile {
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if debug {
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dlog.Println("ignorefile:", p)
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}
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return nil
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}
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if w.ignoreFile(ign, p) {
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if debug {
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dlog.Println("ignored:", p)
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}
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return nil
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}
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if info.Mode()&os.ModeType == 0 {
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modified := info.ModTime().Unix()
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pf := w.previous[p]
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if pf.Modified == modified {
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if nf := uint32(info.Mode()); nf != pf.Flags {
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if debug {
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dlog.Println("new flags:", p)
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}
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pf.Flags = nf
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pf.Version++
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w.previous[p] = pf
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} else if debug {
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dlog.Println("unchanged:", p)
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}
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*res = append(*res, pf)
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return nil
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}
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if w.Suppressor != nil && w.Suppressor.Suppress(p, info) {
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if debug {
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dlog.Println("suppressed:", p)
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}
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if !w.suppressed[p] {
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w.suppressed[p] = true
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log.Printf("INFO: Changes to %q are being temporarily suppressed because it changes too frequently.", p)
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}
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f := pf
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f.Flags = protocol.FlagInvalid
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f.Blocks = nil
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*res = append(*res, f)
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return nil
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} else if w.suppressed[p] {
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log.Printf("INFO: Changes to %q are no longer suppressed.", p)
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delete(w.suppressed, p)
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}
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fd, err := os.Open(p)
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if err != nil {
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return nil
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}
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defer fd.Close()
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t0 := time.Now()
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blocks, err := Blocks(fd, w.BlockSize)
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if err != nil {
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if debug {
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dlog.Println("hash error:", p, err)
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}
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return nil
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}
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if debug {
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t1 := time.Now()
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dlog.Println("hashed:", p, ";", len(blocks), "blocks;", info.Size(), "bytes;", int(float64(info.Size())/1024/t1.Sub(t0).Seconds()), "KB/s")
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}
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f := File{
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Name: p,
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Size: info.Size(),
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Flags: uint32(info.Mode()),
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Modified: modified,
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Blocks: blocks,
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}
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w.previous[p] = f
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*res = append(*res, f)
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}
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return nil
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}
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}
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func (w *Walker) cleanTempFile(path string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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if info.Mode()&os.ModeType == 0 && w.TempNamer.IsTemporary(path) {
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os.Remove(path)
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}
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return nil
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}
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func (w *Walker) ignoreFile(patterns map[string][]string, file string) bool {
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first, last := path.Split(file)
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for prefix, pats := range patterns {
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if len(prefix) == 0 || prefix == first || strings.HasPrefix(first, prefix+"/") {
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for _, pattern := range pats {
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if match, _ := path.Match(pattern, last); match {
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return true
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}
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}
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}
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}
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return false
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}
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