code.delx.au - gnu-emacs/blob - lisp/ls-lisp.el

   1 ;;; ls-lisp.el --- emulate insert-directory completely in Emacs Lisp
   2
   3 ;; Copyright (C) 1992, 1994, 2000 Free Software Foundation, Inc.
   4
   5 ;; Author: Sebastian Kremer <sk@thp.uni-koeln.de>
   6 ;; Modified by: Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>
   7 ;; Maintainer: FSF
   8 ;; Keywords: unix, dired
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  25 ;; Boston, MA 02111-1307, USA.
  26
  27 ;;; Commentary:
  28
  29 ;; OVERVIEW ==========================================================
  30
  31 ;; This file redefines the function `insert-directory' to implement it
  32 ;; directly from Emacs lisp, without running ls in a subprocess.  It
  33 ;; is useful if you cannot afford to fork Emacs on a real memory UNIX,
  34 ;; under VMS or other non-UNIX platforms if you don't have the ls
  35 ;; program, or if you want a different format from what ls offers.
  36
  37 ;; This function can use regexps instead of shell wildcards.  If you
  38 ;; enter regexps remember to double each $ sign.  For example, to
  39 ;; include files *.el, enter `.*\.el$$', resulting in the regexp
  40 ;; `.*\.el$'.
  41
  42 ;; RESTRICTIONS ======================================================
  43
  44 ;; * A few obscure ls switches are still ignored: see the docstring of
  45 ;; `insert-directory'.
  46
  47 ;; * Generally only numeric uid/gid.
  48
  49 ;; TO DO =============================================================
  50
  51 ;; Complete handling of F switch (if/when possible).
  52
  53 ;; FJW: May be able to sort much faster by consing the sort key onto
  54 ;; the front of each list element, sorting and then stripping the key
  55 ;; off again!
  56
  57 ;;; History:
  58
  59 ;; Written originally by Sebastian Kremer <sk@thp.uni-koeln.de>
  60 ;; Revised by Andrew Innes and Geoff Volker (and maybe others).
  61
  62 ;; Modified by Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>, mainly
  63 ;; to support many more ls options, "platform emulation", hooks for
  64 ;; external symbolic link support and more robust sorting.
  65
  66 ;;; Code:
  67
  68 ;;;###autoload
  69 (defgroup ls-lisp nil
  70   "Emulate the ls program completely in Emacs Lisp."
  71   :version "21.1"
  72   :group 'dired)
  73
  74 (defcustom ls-lisp-emulation
  75   (cond ((eq system-type 'macos) 'MacOS)
  76         ;; ((eq system-type 'windows-nt) 'MS-Windows)
  77         ((memq system-type
  78                '(hpux dgux usg-unix-v unisoft-unix rtu irix berkeley-unix))
  79          'UNIX))                        ; very similar to GNU
  80   ;; Anything else defaults to nil, meaning GNU.
  81   "*Platform to emulate: GNU (default), MacOS, MS-Windows, UNIX.
  82 Corresponding value is one of the atoms: nil, MacOS, MS-Windows, UNIX.
  83 Sets default values for: `ls-lisp-ignore-case', `ls-lisp-dirs-first',
  84 `ls-lisp-verbosity'.  Need not match actual platform.  Changing this
  85 option will have no effect until you restart Emacs."
  86   :type '(choice (const :tag "GNU" nil)
  87                  (const MacOS)
  88                  (const MS-Windows)
  89                  (const UNIX))
  90   :group 'ls-lisp)
  91
  92 (defcustom ls-lisp-ignore-case
  93   ;; Name change for consistency with other option names.
  94   (or (memq ls-lisp-emulation '(MS-Windows MacOS))
  95       (and (boundp 'ls-lisp-dired-ignore-case) ls-lisp-dired-ignore-case))
  96   "*Non-nil causes ls-lisp alphabetic sorting to ignore case."
  97   :type 'boolean
  98   :group 'ls-lisp)
  99
 100 (defcustom ls-lisp-dirs-first (eq ls-lisp-emulation 'MS-Windows)
 101   "*Non-nil causes ls-lisp to sort directories first in any ordering.
 102 \(Or last if it is reversed.)  Follows Microsoft Windows Explorer."
 103   ;; Functionality suggested by Chris McMahan <cmcmahan@one.net>
 104   :type 'boolean
 105   :group 'ls-lisp)
 106
 107 (defcustom ls-lisp-verbosity
 108   (cond ((eq ls-lisp-emulation 'MacOS) nil)
 109         ((eq ls-lisp-emulation 'MS-Windows)
 110          (if (and (fboundp 'w32-using-nt) (w32-using-nt))
 111              '(links)))                 ; distinguish NT/2K from 9x
 112         ((eq ls-lisp-emulation 'UNIX) '(links uid)) ; UNIX ls
 113         (t '(links uid gid)))           ; GNU ls
 114   "*A list of optional file attributes that ls-lisp should display.
 115 It should contain none or more of the symbols: links, uid, gid.
 116 nil (or an empty list) means display none of them.
 117
 118 Concepts come from UNIX: `links' means count of names associated with
 119 the file\; `uid' means user (owner) identifier\; `gid' means group
 120 identifier.
 121
 122 If emulation is MacOS then default is nil\;
 123 if emulation is MS-Windows then default is `(links)' if platform is
 124 Windows NT/2K, nil otherwise\;
 125 if emulation is UNIX then default is `(links uid)'\;
 126 if emulation is GNU then default is `(links uid gid)'."
 127   ;; Functionality suggested by Howard Melman <howard@silverstream.com>
 128   :type '(set (const :tag "Show Link Count" links)
 129               (const :tag "Show User" uid)
 130               (const :tag "Show Group" gid))
 131   :group 'ls-lisp)
 132
 133 (defcustom ls-lisp-use-insert-directory-program nil
 134   "*Non-nil causes ls-lisp to revert back to using `insert-directory-program'.
 135 This is useful on platforms where ls-lisp is dumped into Emacs, such as
 136 Microsoft Windows, but you would still like to use a program to list
 137 the contents of a directory."
 138   :type 'boolean
 139   :group 'ls-lisp)
 140
 141 (defcustom ls-lisp-support-shell-wildcards t
 142   "*Non-nil means ls-lisp treats file patterns as shell wildcards.
 143 Otherwise they are treated as Emacs regexps (for backward compatibility)."
 144   :type 'boolean
 145   :group 'ls-lisp)
 146
 147 (defcustom ls-lisp-format-time-list
 148   '("%b %e %H:%M"
 149     "%b %e  %Y")
 150   "*List of `format-time-string' specs to display file time stamps.
 151 They are used whenever a locale is not specified to use instead.
 152
 153 Syntax:  (EARLY-TIME-FORMAT OLD-TIME-FORMAT)
 154
 155 The EARLY-TIME-FORMAT is used if file has been modified within the
 156 current year. The OLD-TIME-FORMAT is used for older files.  To use ISO
 157 8601 dates, you could set:
 158
 159 \(setq ls-lisp-format-time-list
 160        '(\"%Y-%m-%d %H:%M\"
 161          \"%Y-%m-%d      \"))"
 162   :type  '(list string)
 163   :group 'ls-lisp)
 164
 165 ;; Remember the original insert-directory function
 166 (or (featurep 'ls-lisp)  ; FJW: unless this file is being reloaded!
 167     (fset 'original-insert-directory (symbol-function 'insert-directory)))
 168
 169 ;; This stub is to allow ls-lisp to parse symbolic links via another
 170 ;; library such as w32-symlinks.el from
 171 ;; http://centaur.qmw.ac.uk/Emacs/:
 172 (defun ls-lisp-parse-symlink (file-name)
 173   "This stub may be redefined to parse FILE-NAME as a symlink.
 174 It should return nil or the link target as a string."
 175   nil)
 176
 177 \f
 178 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 179
 180 (defun insert-directory (file switches &optional wildcard full-directory-p)
 181   "Insert directory listing for FILE, formatted according to SWITCHES.
 182 Leaves point after the inserted text.
 183 SWITCHES may be a string of options, or a list of strings.
 184 Optional third arg WILDCARD means treat FILE as shell wildcard.
 185 Optional fourth arg FULL-DIRECTORY-P means file is a directory and
 186 switches do not contain `d', so that a full listing is expected.
 187
 188 This version of the function comes from `ls-lisp.el'.
 189 If the value of `ls-lisp-use-insert-directory-program' is non-nil then
 190 it works exactly like the version from `files.el' and runs a directory
 191 listing program whose name is in the variable
 192 `insert-directory-program'; if also WILDCARD is non-nil then it runs
 193 the shell specified by `shell-file-name'.  If the value of
 194 `ls-lisp-use-insert-directory-program' is nil then it runs a Lisp
 195 emulation.
 196
 197 The Lisp emulation does not run any external programs or shells.  It
 198 supports ordinary shell wildcards if `ls-lisp-support-shell-wildcards'
 199 is non-nil; otherwise, it interprets wildcards as regular expressions
 200 to match file names.  It does not support all `ls' switches -- those
 201 that work are: A a c i r S s t u U X g G B C R and F partly."
 202   (if ls-lisp-use-insert-directory-program
 203       (original-insert-directory file switches wildcard full-directory-p)
 204     ;; We need the directory in order to find the right handler.
 205     (let ((handler (find-file-name-handler (expand-file-name file)
 206                                            'insert-directory)))
 207       (if handler
 208           (funcall handler 'insert-directory file switches
 209                    wildcard full-directory-p)
 210         ;; Convert SWITCHES to a list of characters.
 211         (setq switches (delete ?- (append switches nil)))
 212         (if wildcard
 213             (setq wildcard
 214                   (if ls-lisp-support-shell-wildcards
 215                       (wildcard-to-regexp (file-name-nondirectory file))
 216                     (file-name-nondirectory file))
 217                   file (file-name-directory file))
 218           (if (memq ?B switches) (setq wildcard "[^~]\\'")))
 219         (ls-lisp-insert-directory
 220          file switches (ls-lisp-time-index switches)
 221          wildcard full-directory-p)
 222         ;; Try to insert the amount of free space.
 223         (save-excursion
 224           (goto-char (point-min))
 225           ;; First find the line to put it on.
 226           (when (re-search-forward "^total" nil t)
 227             (let ((available (get-free-disk-space ".")))
 228               (when available
 229                 ;; Replace "total" with "total used", to avoid confusion.
 230                 (replace-match "total used in directory")
 231                 (end-of-line)
 232                 (insert " available " available)))))))))
 233
 234 (defun ls-lisp-insert-directory
 235   (file switches time-index wildcard full-directory-p)
 236   "Insert directory listing for FILE, formatted according to SWITCHES.
 237 Leaves point after the inserted text.  This is an internal function
 238 optionally called by the `ls-lisp.el' version of `insert-directory'.
 239 It is called recursively if the -R switch is used.
 240 SWITCHES is a *list* of characters.  TIME-INDEX is the time index into
 241 file-attributes according to SWITCHES.  WILDCARD is nil or an *Emacs
 242 regexp*.  FULL-DIRECTORY-P means file is a directory and SWITCHES does
 243 not contain `d', so that a full listing is expected."
 244   ;; Sometimes we get ".../foo*/" as FILE.  While the shell and
 245   ;; `ls' don't mind, we certainly do, because it makes us think
 246   ;; there is no wildcard, only a directory name.
 247   (if (and ls-lisp-support-shell-wildcards
 248            (string-match "[[?*]" file))
 249       (progn
 250         (or (not (eq (aref file (1- (length file))) ?/))
 251             (setq file (substring file 0 (1- (length file)))))
 252         (setq wildcard t)))
 253   (if (or wildcard full-directory-p)
 254       (let* ((dir (file-name-as-directory file))
 255              (default-directory dir)    ; so that file-attributes works
 256              (file-alist
 257               (directory-files-and-attributes dir nil wildcard t))
 258              (now (current-time))
 259              (sum 0)
 260              ;; do all bindings here for speed
 261              total-line files elt short file-size fil attr)
 262         (cond ((memq ?A switches)
 263                (setq file-alist
 264                      (ls-lisp-delete-matching "^\\.\\.?$" file-alist)))
 265               ((not (memq ?a switches))
 266                ;; if neither -A  nor -a, flush . files
 267                (setq file-alist
 268                      (ls-lisp-delete-matching "^\\." file-alist))))
 269         (setq file-alist
 270               (ls-lisp-handle-switches file-alist switches))
 271         (if (memq ?C switches)          ; column (-C) format
 272             (ls-lisp-column-format file-alist)
 273           (setq total-line (cons (point) (car-safe file-alist)))
 274           (setq files file-alist)
 275           (while files                  ; long (-l) format
 276             (setq elt (car files)
 277                   files (cdr files)
 278                   short (car elt)
 279                   attr (cdr elt)
 280                   file-size (nth 7 attr))
 281             (and attr
 282                  (setq sum (+ file-size
 283                               ;; Even if neither SUM nor file's size
 284                               ;; overflow, their sum could.
 285                               (if (or (< sum (- 134217727 file-size))
 286                                       (floatp sum)
 287                                       (floatp file-size))
 288                                   sum
 289                                 (float sum))))
 290                  (insert (ls-lisp-format short attr file-size
 291                                          switches time-index now))))
 292           ;; Insert total size of all files:
 293           (save-excursion
 294             (goto-char (car total-line))
 295             (or (cdr total-line)
 296                 ;; Shell says ``No match'' if no files match
 297                 ;; the wildcard; let's say something similar.
 298                 (insert "(No match)\n"))
 299             (insert (format "total %.0f\n" (fceiling (/ sum 1024.0))))))
 300         (if (memq ?R switches)
 301             ;; List the contents of all directories recursively.
 302             ;; cadr of each element of `file-alist' is t for
 303             ;; directory, string (name linked to) for symbolic
 304             ;; link, or nil.
 305             (while file-alist
 306               (setq elt (car file-alist)
 307                     file-alist (cdr file-alist))
 308               (when (and (eq (cadr elt) t) ; directory
 309                          (not (string-match "\\`\\.\\.?\\'" (car elt))))
 310                 (setq elt (expand-file-name (car elt) dir))
 311                 (insert "\n" elt ":\n")
 312                 (ls-lisp-insert-directory
 313                  elt switches time-index wildcard full-directory-p)))))
 314     ;; If not full-directory-p, FILE *must not* end in /, as
 315     ;; file-attributes will not recognize a symlink to a directory,
 316     ;; so must make it a relative filename as ls does:
 317     (if (eq (aref file (1- (length file))) ?/)
 318         (setq file (substring file 0 -1)))
 319     (let ((fattr (file-attributes file)))
 320       (if fattr
 321           (insert (ls-lisp-format file fattr (nth 7 fattr)
 322                                   switches time-index (current-time)))
 323         (message "%s: doesn't exist or is inaccessible" file)
 324         (ding) (sit-for 2)))))          ; to show user the message!
 325
 326 (defun ls-lisp-column-format (file-alist)
 327   "Insert the file names (only) in FILE-ALIST into the current buffer.
 328 Format in columns, sorted vertically, following GNU ls -C.
 329 Responds to the window width as ls should but may not!"
 330   (let (files fmt ncols collen (nfiles 0) (colwid 0))
 331     ;; Count number of files as `nfiles', build list of filenames as
 332     ;; `files', and find maximum filename length as `colwid':
 333     (let (file len)
 334       (while file-alist
 335         (setq nfiles (1+ nfiles)
 336               file (caar file-alist)
 337               files (cons file files)
 338               file-alist (cdr file-alist)
 339               len (length file))
 340         (if (> len colwid) (setq colwid len))))
 341     (setq files (nreverse files)
 342           colwid (+ 2 colwid)           ; 2 character column gap
 343           fmt (format "%%-%ds" colwid)  ; print format
 344           ncols (/ (window-width) colwid) ; no of columns
 345           collen (/ nfiles ncols))      ; floor of column length
 346     (if (> nfiles (* collen ncols)) (setq collen (1+ collen)))
 347     ;; Output the file names in columns, sorted vertically:
 348     (let ((i 0) j)
 349       (while (< i collen)
 350         (setq j i)
 351         (while (< j nfiles)
 352           (insert (format fmt (nth j files)))
 353           (setq j (+ j collen)))
 354         ;; FJW: This is completely unnecessary, but I don't like
 355         ;; trailing white space...
 356         (delete-region (point) (progn (skip-chars-backward " \t") (point)))
 357         (insert ?\n)
 358         (setq i (1+ i))))))
 359
 360 (defun ls-lisp-delete-matching (regexp list)
 361   "Delete all elements matching REGEXP from LIST, return new list."
 362   ;; Should perhaps use setcdr for efficiency.
 363   (let (result)
 364     (while list
 365       (or (string-match regexp (caar list))
 366           (setq result (cons (car list) result)))
 367       (setq list (cdr list)))
 368     result))
 369
 370 (defsubst ls-lisp-string-lessp (s1 s2)
 371   "Return t if string S1 is less than string S2 in lexicographic order.
 372 Case is significant if `ls-lisp-ignore-case' is nil.
 373 Unibyte strings are converted to multibyte for comparison."
 374   (let ((u (compare-strings s1 0 nil s2 0 nil ls-lisp-ignore-case)))
 375     (and (numberp u) (< u 0))))
 376
 377 (defun ls-lisp-handle-switches (file-alist switches)
 378   "Return new FILE-ALIST sorted according to SWITCHES.
 379 SWITCHES is a list of characters.  Default sorting is alphabetic."
 380   ;; FILE-ALIST's elements are (FILE . FILE-ATTRIBUTES).
 381   (or (memq ?U switches)                ; unsorted
 382       ;; Catch and ignore unexpected sorting errors
 383       (condition-case err
 384           (setq file-alist
 385                 (let (index)
 386                   ;; Copy file-alist in case of error
 387                   (sort (copy-sequence file-alist) ; modifies its argument!
 388                         (cond ((memq ?S switches)
 389                                (lambda (x y) ; sorted on size
 390                                  ;; 7th file attribute is file size
 391                                  ;; Make largest file come first
 392                                  (< (nth 7 (cdr y))
 393                                     (nth 7 (cdr x)))))
 394                               ((setq index (ls-lisp-time-index switches))
 395                                (lambda (x y) ; sorted on time
 396                                  (ls-lisp-time-lessp (nth index (cdr y))
 397                                                      (nth index (cdr x)))))
 398                               ((memq ?X switches)
 399                                (lambda (x y) ; sorted on extension
 400                                  (ls-lisp-string-lessp
 401                                   (ls-lisp-extension (car x))
 402                                   (ls-lisp-extension (car y)))))
 403                               (t
 404                                (lambda (x y) ; sorted alphabetically
 405                                  (ls-lisp-string-lessp (car x) (car y))))))))
 406         (error (message "Unsorted (ls-lisp sorting error) - %s"
 407                         (error-message-string err))
 408                (ding) (sit-for 2))))    ; to show user the message!
 409   (if (memq ?F switches)                ; classify switch
 410       (setq file-alist (mapcar 'ls-lisp-classify file-alist)))
 411   (if ls-lisp-dirs-first
 412   ;; Re-sort directories first, without otherwise changing the
 413   ;; ordering, and reverse whole list.  cadr of each element of
 414   ;; `file-alist' is t for directory, string (name linked to) for
 415   ;; symbolic link, or nil.
 416       (let (el dirs files)
 417         (while file-alist
 418           (if (eq (cadr (setq el (car file-alist))) t) ; directory
 419               (setq dirs (cons el dirs))
 420             (setq files (cons el files)))
 421           (setq file-alist (cdr file-alist)))
 422         (setq file-alist
 423               (if (memq ?U switches)    ; unsorted order is reversed
 424                   (nconc dirs files)
 425                 (nconc files dirs)
 426                 ))))
 427   ;; Finally reverse file alist if necessary.
 428   ;; (eq below MUST compare `(not (memq ...))' to force comparison of
 429   ;; `t' or `nil', rather than list tails!)
 430   (if (eq (eq (not (memq ?U switches))  ; unsorted order is reversed
 431               (not (memq ?r switches))) ; reversed sort order requested
 432           ls-lisp-dirs-first)           ; already reversed
 433       (nreverse file-alist)
 434     file-alist))
 435
 436 (defun ls-lisp-classify (filedata)
 437   "Append a character to each file name indicating the file type.
 438 Also, for regular files that are executable, append `*'.
 439 The file type indicators are `/' for directories, `@' for symbolic
 440 links, `|' for FIFOs, `=' for sockets, and nothing for regular files.
 441 \[But FIFOs and sockets are not recognised.]
 442 FILEDATA has the form (filename . `file-attributes').  Its `cadr' is t
 443 for directory, string (name linked to) for symbolic link, or nil."
 444   (let ((dir (cadr filedata)) (file-name (car filedata)))
 445     (cond ((or dir
 446                ;; Parsing .lnk files here is perhaps overkill!
 447                (setq dir (ls-lisp-parse-symlink file-name)))
 448            (cons
 449             (concat file-name (if (eq dir t) "/" "@"))
 450             (cdr filedata)))
 451           ((string-match "x" (nth 9 filedata))
 452            (cons
 453             (concat file-name "*")
 454             (cdr filedata)))
 455           (t filedata))))
 456
 457 (defun ls-lisp-extension (filename)
 458   "Return extension of FILENAME (ignoring any version extension)
 459 FOLLOWED by null and full filename, SOLELY for full alpha sort."
 460   ;; Force extension sort order: `no ext' then `null ext' then `ext'
 461   ;; to agree with GNU ls.
 462   (concat
 463    (let* ((i (length filename)) end)
 464      (if (= (aref filename (1- i)) ?.) ; null extension
 465          "\0"
 466        (while (and (>= (setq i (1- i)) 0)
 467                    (/= (aref filename i) ?.)))
 468        (if (< i 0) "\0\0"               ; no extension
 469          (if (/= (aref filename (1+ i)) ?~)
 470              (substring filename (1+ i))
 471            ;; version extension found -- ignore it
 472            (setq end i)
 473            (while (and (>= (setq i (1- i)) 0)
 474                        (/= (aref filename i) ?.)))
 475            (if (< i 0) "\0\0"   ; no extension
 476              (substring filename (1+ i) end))))
 477        )) "\0" filename))
 478
 479 ;; From Roland McGrath.  Can use this to sort on time.
 480 (defun ls-lisp-time-lessp (time0 time1)
 481   "Return t if time TIME0 is earlier than time TIME1."
 482   (let ((hi0 (car time0)) (hi1 (car time1)))
 483     (or (< hi0 hi1)
 484         (and (= hi0 hi1)
 485              (< (cadr time0) (cadr time1))))))
 486
 487 (defun ls-lisp-format (file-name file-attr file-size switches time-index now)
 488   "Format one line of long ls output for file FILE-NAME.
 489 FILE-ATTR and FILE-SIZE give the file's attributes and size.
 490 SWITCHES, TIME-INDEX and NOW give the full switch list and time data."
 491   (let ((file-type (nth 0 file-attr))
 492         ;; t for directory, string (name linked to)
 493         ;; for symbolic link, or nil.
 494         (drwxrwxrwx (nth 8 file-attr))) ; attribute string ("drwxrwxrwx")
 495     (and (null file-type)
 496          ;; Maybe no kernel support for symlinks, so...
 497          (setq file-type (ls-lisp-parse-symlink file-name))
 498          (aset drwxrwxrwx 0 ?l)) ; symbolic link - update attribute string
 499     (concat (if (memq ?i switches)      ; inode number
 500                 (format " %6d" (nth 10 file-attr)))
 501             ;; nil is treated like "" in concat
 502             (if (memq ?s switches)      ; size in K
 503                 (format " %4.0f" (fceiling (/ file-size 1024.0))))
 504             drwxrwxrwx                  ; attribute string
 505             (if (memq 'links ls-lisp-verbosity)
 506                 (format " %3d" (nth 1 file-attr))) ; link count
 507             ;; Numeric uid/gid are more confusing than helpful;
 508             ;; Emacs should be able to make strings of them.
 509             ;; They tend to be bogus on non-UNIX platforms anyway so
 510             ;; optionally hide them.
 511             (if (memq 'uid ls-lisp-verbosity)
 512                 ;; (user-login-name uid) works on Windows NT but not
 513                 ;; on 9x and maybe not on some other platforms, so...
 514                 (let ((uid (nth 2 file-attr)))
 515                   (if (= uid (user-uid))
 516                       (format " %-8s" (user-login-name))
 517                     (format " %-8d" uid))))
 518             (if (not (memq ?G switches)) ; GNU ls -- shows group by default
 519                 (if (or (memq ?g switches) ; UNIX ls -- no group by default
 520                         (memq 'gid ls-lisp-verbosity))
 521                     (if (memq system-type '(macos windows-nt ms-dos))
 522                         ;; No useful concept of group...
 523                         " root"
 524                       (let* ((gid (nth 3 file-attr))
 525                              (group (user-login-name gid)))
 526                         (if group
 527                             (format " %-8s" group)
 528                           (format " %-8d" gid))))))
 529             (format (if (floatp file-size) " %8.0f" " %8d") file-size)
 530             " "
 531             (ls-lisp-format-time file-attr time-index now)
 532             " "
 533             file-name
 534             (if (stringp file-type)     ; is a symbolic link
 535                 (concat " -> " file-type))
 536             "\n"
 537             )))
 538
 539 (defun ls-lisp-time-index (switches)
 540   "Return time index into file-attributes according to ls SWITCHES list.
 541 Return nil if no time switch found."
 542   ;; FJW: Default of nil is IMPORTANT and used in `ls-lisp-handle-switches'!
 543   (cond ((memq ?c switches) 6)          ; last mode change
 544         ((memq ?t switches) 5)          ; last modtime
 545         ((memq ?u switches) 4)))        ; last access
 546
 547 (defun ls-lisp-time-to-seconds (time)
 548   "Convert TIME to a floating point number."
 549   (+ (* (car time) 65536.0)
 550      (cadr time)
 551      (/ (or (nth 2 time) 0) 1000000.0)))
 552
 553 (defun ls-lisp-format-time (file-attr time-index now)
 554   "Format time for file with attributes FILE-ATTR according to TIME-INDEX.
 555 Use the same method as ls to decide whether to show time-of-day or year,
 556 depending on distance between file date and NOW.
 557 All ls time options, namely c, t and u, are handled."
 558   (let* ((time (nth (or time-index 5) file-attr)) ; default is last modtime
 559          (diff (- (ls-lisp-time-to-seconds time)
 560                   (ls-lisp-time-to-seconds now)))
 561          ;; Consider a time to be recent if it is within the past six
 562          ;; months.  A Gregorian year has 365.2425 * 24 * 60 * 60 ==
 563          ;; 31556952 seconds on the average, and half of that is 15778476.
 564          ;; Write the constant explicitly to avoid roundoff error.
 565          (past-cutoff -15778476)) ; half a Gregorian year
 566     (condition-case nil
 567         ;; Use traditional time format in the C or POSIX locale,
 568         ;; ISO-style time format otherwise, so columns line up.
 569         (let ((locale system-time-locale))
 570           (if (not locale)
 571               (let ((vars '("LC_ALL" "LC_TIME" "LANG")))
 572                 (while (and vars (not (setq locale (getenv (car vars)))))
 573                   (setq vars (cdr vars)))))
 574           (if (member locale '("C" "POSIX"))
 575               (setq locale nil))
 576           (format-time-string
 577            (if (and (<= past-cutoff diff) (<= diff 0))
 578                (if locale "%m-%d %H:%M" (nth 0 ls-lisp-format-time-list))
 579              (if locale "%Y-%m-%d " (nth 1 ls-lisp-format-time-list)))
 580            time))
 581       (error "Unk  0  0000"))))
 582
 583 (provide 'ls-lisp)
 584
 585 ;;; ls-lisp.el ends here