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- // Copyright 2009 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- package os
- import (
- "internal/poll"
- "io"
- "syscall"
- "unsafe"
- )
- // FIXME: pathconf returns long, not int.
- //extern pathconf
- func libc_pathconf(*byte, int32) int
- func direntType(*syscall.Dirent) byte
- func clen(n []byte) int {
- for i := 0; i < len(n); i++ {
- if n[i] == 0 {
- return i
- }
- }
- return len(n)
- }
- func (f *File) readdir(n int, mode readdirMode) (names []string, dirents []DirEntry, infos []FileInfo, err error) {
- // If this file has no dirinfo, create one.
- if f.dirinfo == nil {
- fd, call, err := poll.DupCloseOnExec(int(f.pfd.Sysfd))
- if err != nil {
- return nil, nil, nil, NewSyscallError(call, err)
- }
- syscall.Entersyscall()
- r := libc_fdopendir(int32(fd))
- errno := syscall.GetErrno()
- syscall.Exitsyscall()
- if r == nil {
- return nil, nil, nil, &PathError{"fdopendir", f.name, errno}
- }
- f.dirinfo = &dirInfo{r}
- }
- dir := f.dirinfo.dir
- // Change the meaning of n for the implementation below.
- //
- // The n above was for the public interface of "if n <= 0,
- // Readdir returns all the FileInfo from the directory in a
- // single slice".
- //
- // But below, we use only negative to mean looping until the
- // end and positive to mean bounded, with positive
- // terminating at 0.
- if n == 0 {
- n = -1
- }
- for n != 0 {
- syscall.Entersyscall()
- syscall.SetErrno(0)
- dirent := libc_readdir(dir)
- errno := syscall.GetErrno()
- syscall.Exitsyscall()
- if dirent == nil {
- if errno != 0 {
- return names, dirents, infos, &PathError{Op: "readdir", Path: f.name, Err: errno}
- }
- break // EOF
- }
- // In some cases the actual name can be longer than
- // the Name field.
- name := (*[1 << 16]byte)(unsafe.Pointer(&dirent.Name[0]))[:]
- for i, c := range name {
- if c == 0 {
- name = name[:i]
- break
- }
- }
- // Check for useless names before allocating a string.
- if (len(name) == 1 && name[0] == '.') || (len(name) == 2 && name[0] == '.' && name[1] == '.') {
- continue
- }
- if n > 0 { // see 'n == 0' comment above
- n--
- }
- if mode == readdirName {
- names = append(names, string(name))
- } else if mode == readdirDirEntry {
- var typ FileMode
- switch direntType(dirent) {
- case 'B':
- typ = ModeDevice
- case 'C':
- typ = ModeDevice | ModeCharDevice
- case 'D':
- typ = ModeDir
- case 'F':
- typ = ModeNamedPipe
- case 'L':
- typ = ModeSymlink
- case 'R':
- typ = 0
- case 'S':
- typ = ModeSocket
- case 'U':
- typ = ^FileMode(0)
- }
- de, err := newUnixDirent(f.name, string(name), typ)
- if IsNotExist(err) {
- // File disappeared between readdir and stat.
- // Treat as if it didn't exist.
- continue
- }
- if err != nil {
- return nil, dirents, nil, err
- }
- dirents = append(dirents, de)
- } else {
- info, err := lstat(f.name + "/" + string(name))
- if IsNotExist(err) {
- // File disappeared between readdir + stat.
- // Treat as if it didn't exist.
- continue
- }
- if err != nil {
- return nil, nil, infos, err
- }
- infos = append(infos, info)
- }
- }
- if n > 0 && len(names)+len(dirents)+len(infos) == 0 {
- return nil, nil, nil, io.EOF
- }
- return names, dirents, infos, nil
- }
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