ls-lisp.el and w32-symlinks.el

[Lars Hansen]

I have looked on symlink handling in ls-lisp.el, and that made me wonder
what the stub `ls-lisp-parse-symlink' was all about. Since the comment
mentions the module w32-symlinks.el from
http://centaur.maths.qmw.ac.uk/Emacs/ (not part of Emacs), I looked into
that as well.
w32-symlinks.el uses filename magic to handle symlinks on w32, but there
is a number of bugs and shortcomings. I have fixed those, and as a
consequence w32-symlinks.el becomes a stand-alone module and
`ls-lisp-parse-symlink' is no longer needed. Therefore I suggest the
attached patch to ls-lisp.el. The patch also makes `ls-lisp-dirs-first'
recognize symlinks to directories.

If there are no objections, I will commit in a few days.

I have e-mailed my patched version of w32-symlinks.el to Francis J.
Wright some time ago asking him to put it on his web page, but that has
not happened (yet). If any of you want it, I can e-mail it to you. With
my patches w32-symlinks.el seems pretty mature ;-) so maybe it should
become part of Emacs (not that I really care personally). But I don't
know about possible legal implications.

*** ls-lisp.1.57.el     2005-08-08 14:15:26.000000000 +0200
--- ls-lisp.1.57.patched.el     2005-11-10 15:49:59.000000000 +0100
***************
*** 45,52 ****
  ;; * A few obscure ls switches are still ignored: see the docstring of
  ;; `insert-directory'.
  
- ;; * Generally only numeric uid/gid.
- 
  ;; TO DO =============================================================
  
  ;; Complete handling of F switch (if/when possible).
--- 45,50 ----
***************
*** 61,68 ****
  ;; Revised by Andrew Innes and Geoff Volker (and maybe others).
  
  ;; Modified by Francis J. Wright <address@hidden>, mainly
! ;; to support many more ls options, "platform emulation", hooks for
! ;; external symbolic link support and more robust sorting.
  
  ;;; Code:
  
--- 59,66 ----
  ;; Revised by Andrew Innes and Geoff Volker (and maybe others).
  
  ;; Modified by Francis J. Wright <address@hidden>, mainly
! ;; to support many more ls options, "platform emulation" and more
! ;; robust sorting.
  
  ;;; Code:
  
***************
*** 175,188 ****
  (or (featurep 'ls-lisp)  ; FJW: unless this file is being reloaded!
      (setq original-insert-directory (symbol-function 'insert-directory)))
  
- ;; This stub is to allow ls-lisp to parse symbolic links via another
- ;; library such as w32-symlinks.el from
- ;; http://centaur.maths.qmw.ac.uk/Emacs/:
- (defun ls-lisp-parse-symlink (file-name)
-   "This stub may be redefined to parse FILE-NAME as a symlink.
- It should return nil or the link target as a string."
-   nil)
- 
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  
--- 173,178 ----
***************
*** 429,435 ****
    ;; symbolic link, or nil.
        (let (el dirs files)
        (while file-alist
!         (if (eq (cadr (setq el (car file-alist))) t) ; directory
              (setq dirs (cons el dirs))
            (setq files (cons el files)))
          (setq file-alist (cdr file-alist)))
--- 419,427 ----
    ;; symbolic link, or nil.
        (let (el dirs files)
        (while file-alist
!         (if (or (eq (cadr (setq el (car file-alist))) t) ; directory
!                   (and (stringp (cadr el))
!                        (file-directory-p (cadr el)))) ; symlink to a directory
              (setq dirs (cons el dirs))
            (setq files (cons el files)))
          (setq file-alist (cdr file-alist)))
***************
*** 455,466 ****
  \[But FIFOs and sockets are not recognized.]
  FILEDATA has the form (filename . `file-attributes').  Its `cadr' is t
  for directory, string (name linked to) for symbolic link, or nil."
!   (let ((dir (cadr filedata)) (file-name (car filedata)))
!     (cond ((or dir
!              ;; Parsing .lnk files here is perhaps overkill!
!              (setq dir (ls-lisp-parse-symlink file-name)))
           (cons
!           (concat file-name (if (eq dir t) "/" "@"))
            (cdr filedata)))
          ((string-match "x" (nth 9 filedata))
           (cons
--- 447,457 ----
  \[But FIFOs and sockets are not recognized.]
  FILEDATA has the form (filename . `file-attributes').  Its `cadr' is t
  for directory, string (name linked to) for symbolic link, or nil."
!   (let ((file-name (car filedata))
!         (type (cadr filedata)))
!     (cond (type
           (cons
!           (concat file-name (if (eq type t) "/" "@"))
            (cdr filedata)))
          ((string-match "x" (nth 9 filedata))
           (cons
***************
*** 506,515 ****
        ;; t for directory, string (name linked to)
        ;; for symbolic link, or nil.
        (drwxrwxrwx (nth 8 file-attr))) ; attribute string ("drwxrwxrwx")
-     (and (null file-type)
-        ;; Maybe no kernel support for symlinks, so...
-        (setq file-type (ls-lisp-parse-symlink file-name))
-        (aset drwxrwxrwx 0 ?l)) ; symbolic link - update attribute string
      (concat (if (memq ?i switches)    ; inode number
                (format " %6d" (nth 10 file-attr)))
            ;; nil is treated like "" in concat
--- 497,502 ----