package pipe import ( "errors" "fmt" "os" "path" "path/filepath" "sort" "github.com/restic/restic/debug" ) type Result interface{} type Job interface { Path() string Fullpath() string Error() error Info() os.FileInfo Result() chan<- Result } type Entry struct { basedir string path string info os.FileInfo error error result chan<- Result // points to the old node if available, interface{} is used to prevent // circular import Node interface{} } func (e Entry) Path() string { return e.path } func (e Entry) Fullpath() string { return filepath.Join(e.basedir, e.path) } func (e Entry) Error() error { return e.error } func (e Entry) Info() os.FileInfo { return e.info } func (e Entry) Result() chan<- Result { return e.result } type Dir struct { basedir string path string error error info os.FileInfo Entries [](<-chan Result) result chan<- Result } func (e Dir) Path() string { return e.path } func (e Dir) Fullpath() string { return filepath.Join(e.basedir, e.path) } func (e Dir) Error() error { return e.error } func (e Dir) Info() os.FileInfo { return e.info } func (e Dir) Result() chan<- Result { return e.result } // readDirNames reads the directory named by dirname and returns // a sorted list of directory entries. // taken from filepath/path.go func readDirNames(dirname string) ([]string, error) { f, err := os.Open(dirname) if err != nil { return nil, err } names, err := f.Readdirnames(-1) f.Close() if err != nil { return nil, err } sort.Strings(names) return names, nil } func isDir(fi os.FileInfo) bool { return fi.IsDir() } func isFile(fi os.FileInfo) bool { return fi.Mode()&(os.ModeType|os.ModeCharDevice) == 0 } var errCancelled = errors.New("walk cancelled") func walk(basedir, dir string, done chan struct{}, jobs chan<- Job, res chan<- Result) error { info, err := os.Lstat(dir) if err != nil { return err } relpath, _ := filepath.Rel(basedir, dir) if !info.IsDir() { select { case jobs <- Entry{info: info, basedir: basedir, path: relpath, result: res}: case <-done: return errCancelled } return nil } names, err := readDirNames(dir) if err != nil { return err } // Insert breakpoint to allow testing behaviour with vanishing files // between Readdir() and lstat() debug.BreakIf("pipe.walk1", func() bool { match, err := path.Match(os.Getenv("DEBUG_BREAK_PIPE"), relpath) if err != nil { panic(err) } if match { debug.Log("break", "break pattern matches for %v\n", relpath) } return match }) entries := make([]<-chan Result, 0, len(names)) for _, name := range names { subpath := filepath.Join(dir, name) ch := make(chan Result, 1) entries = append(entries, ch) fi, err := os.Lstat(subpath) if err != nil { select { case jobs <- Entry{info: fi, error: err, basedir: basedir, path: filepath.Join(relpath, name), result: ch}: case <-done: return errCancelled } continue } // Insert breakpoint to allow testing behaviour with vanishing files // between walk and open debug.BreakIf("pipe.walk2", func() bool { p := filepath.Join(relpath, name) match, err := path.Match(os.Getenv("DEBUG_BREAK_PIPE"), p) if err != nil { panic(err) } if match { debug.Log("break", "break pattern matches for %v\n", p) } return match }) if isDir(fi) { err = walk(basedir, subpath, done, jobs, ch) if err != nil { return err } } else { select { case jobs <- Entry{info: fi, basedir: basedir, path: filepath.Join(relpath, name), result: ch}: case <-done: return errCancelled } } } select { case jobs <- Dir{basedir: basedir, path: relpath, info: info, Entries: entries, result: res}: case <-done: return errCancelled } return nil } // Walk sends a Job for each file and directory it finds below the paths. When // the channel done is closed, processing stops. func Walk(paths []string, done chan struct{}, jobs chan<- Job, res chan<- Result) error { defer func() { debug.Log("pipe.Walk", "output channel closed") close(jobs) }() entries := make([]<-chan Result, 0, len(paths)) for _, path := range paths { debug.Log("pipe.Walk", "start walker for %v", path) ch := make(chan Result, 1) entries = append(entries, ch) err := walk(filepath.Dir(path), path, done, jobs, ch) if err != nil { return err } debug.Log("pipe.Walk", "walker for %v done", path) } debug.Log("pipe.Walk", "sending root node") select { case <-done: return errCancelled case jobs <- Dir{Entries: entries, result: res}: } debug.Log("pipe.Walk", "walker done") return nil } // Split feeds all elements read from inChan to dirChan and entChan. func Split(inChan <-chan Job, dirChan chan<- Dir, entChan chan<- Entry) { debug.Log("pipe.Split", "start") defer debug.Log("pipe.Split", "done") inCh := inChan dirCh := dirChan entCh := entChan var ( dir Dir ent Entry ) // deactivate sending until we received at least one job dirCh = nil entCh = nil for { select { case job, ok := <-inCh: if !ok { // channel is closed return } if job == nil { panic("nil job received") } // disable receiving until the current job has been sent inCh = nil switch j := job.(type) { case Dir: dir = j dirCh = dirChan case Entry: ent = j entCh = entChan default: panic(fmt.Sprintf("unknown job type %v", j)) } case dirCh <- dir: // disable sending, re-enable receiving dirCh = nil inCh = inChan case entCh <- ent: // disable sending, re-enable receiving entCh = nil inCh = inChan } } }