lisp/ls-lisp.el

   1 ;;; ls-lisp.el --- emulate insert-directory completely in Emacs Lisp
   2
   3 ;; Copyright (C) 1992, 1994, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007 Free Software Foundation, Inc.
   5
   6 ;; Author: Sebastian Kremer <sk@thp.uni-koeln.de>
   7 ;; Modified by: Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>
   8 ;; Maintainer: FSF
   9 ;; Keywords: unix, dired
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 2, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  26 ;; Boston, MA 02110-1301, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; OVERVIEW ==========================================================
  31
  32 ;; This file redefines the function `insert-directory' to implement it
  33 ;; directly from Emacs lisp, without running ls in a subprocess.  It
  34 ;; is useful if you cannot afford to fork Emacs on a real memory UNIX,
  35 ;; under VMS or other non-UNIX platforms if you don't have the ls
  36 ;; program, or if you want a different format from what ls offers.
  37
  38 ;; This function can use regexps instead of shell wildcards.  If you
  39 ;; enter regexps remember to double each $ sign.  For example, to
  40 ;; include files *.el, enter `.*\.el$$', resulting in the regexp
  41 ;; `.*\.el$'.
  42
  43 ;; RESTRICTIONS ======================================================
  44
  45 ;; * A few obscure ls switches are still ignored: see the docstring of
  46 ;; `insert-directory'.
  47
  48 ;; TO DO =============================================================
  49
  50 ;; Complete handling of F switch (if/when possible).
  51
  52 ;; FJW: May be able to sort much faster by consing the sort key onto
  53 ;; the front of each list element, sorting and then stripping the key
  54 ;; off again!
  55
  56 ;;; History:
  57
  58 ;; Written originally by Sebastian Kremer <sk@thp.uni-koeln.de>
  59 ;; Revised by Andrew Innes and Geoff Volker (and maybe others).
  60
  61 ;; Modified by Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>, mainly
  62 ;; to support many more ls options, "platform emulation" and more
  63 ;; robust sorting.
  64
  65 ;;; Code:
  66
  67 (eval-when-compile (require 'cl))
  68
  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 A value of 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
 134   (not (memq system-type '(macos ms-dos windows-nt)))
 135   "*Non-nil causes ls-lisp to revert back to using `insert-directory-program'.
 136 This is useful on platforms where ls-lisp is dumped into Emacs, such as
 137 Microsoft Windows, but you would still like to use a program to list
 138 the contents of a directory."
 139   :type 'boolean
 140   :group 'ls-lisp)
 141
 142 ;;; Autoloaded because it is let-bound in `recover-session', `mail-recover-1'.
 143 ;;;###autoload
 144 (defcustom ls-lisp-support-shell-wildcards t
 145   "*Non-nil means ls-lisp treats file patterns as shell wildcards.
 146 Otherwise they are treated as Emacs regexps (for backward compatibility)."
 147   :type 'boolean
 148   :group 'ls-lisp)
 149
 150 (defcustom ls-lisp-format-time-list
 151   '("%b %e %H:%M"
 152     "%b %e  %Y")
 153   "*List of `format-time-string' specs to display file time stamps.
 154 These specs are used ONLY if a valid locale can not be determined.
 155
 156 If `ls-lisp-use-localized-time-format' is non-nil, these specs are used
 157 regardless of whether the locale can be determined.
 158
 159 Syntax:  (EARLY-TIME-FORMAT OLD-TIME-FORMAT)
 160
 161 The EARLY-TIME-FORMAT is used if file has been modified within the
 162 current year. The OLD-TIME-FORMAT is used for older files.  To use ISO
 163 8601 dates, you could set:
 164
 165 \(setq ls-lisp-format-time-list
 166        '(\"%Y-%m-%d %H:%M\"
 167          \"%Y-%m-%d      \"))"
 168   :type '(list (string :tag "Early time format")
 169                (string :tag "Old time format"))
 170   :group 'ls-lisp)
 171
 172 (defcustom ls-lisp-use-localized-time-format nil
 173   "*Non-nil causes ls-lisp to use `ls-lisp-format-time-list' even if
 174 a valid locale is specified.
 175
 176 WARNING: Using localized date/time format might cause Dired columns
 177 to fail to lign up, e.g. if month names are not all of the same length."
 178   :type 'boolean
 179   :group 'ls-lisp)
 180
 181 (defvar original-insert-directory nil
 182   "This holds the original function definition of `insert-directory'.")
 183
 184 ;; Remember the original insert-directory function
 185 (or (featurep 'ls-lisp)  ; FJW: unless this file is being reloaded!
 186     (setq original-insert-directory (symbol-function 'insert-directory)))
 187
 188 \f
 189 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 190
 191 (defun insert-directory (file switches &optional wildcard full-directory-p)
 192   "Insert directory listing for FILE, formatted according to SWITCHES.
 193 Leaves point after the inserted text.
 194 SWITCHES may be a string of options, or a list of strings.
 195 Optional third arg WILDCARD means treat FILE as shell wildcard.
 196 Optional fourth arg FULL-DIRECTORY-P means file is a directory and
 197 switches do not contain `d', so that a full listing is expected.
 198
 199 This version of the function comes from `ls-lisp.el'.
 200 If the value of `ls-lisp-use-insert-directory-program' is non-nil then
 201 it works exactly like the version from `files.el' and runs a directory
 202 listing program whose name is in the variable
 203 `insert-directory-program'; if also WILDCARD is non-nil then it runs
 204 the shell specified by `shell-file-name'.  If the value of
 205 `ls-lisp-use-insert-directory-program' is nil then it runs a Lisp
 206 emulation.
 207
 208 The Lisp emulation does not run any external programs or shells.  It
 209 supports ordinary shell wildcards if `ls-lisp-support-shell-wildcards'
 210 is non-nil; otherwise, it interprets wildcards as regular expressions
 211 to match file names.  It does not support all `ls' switches -- those
 212 that work are: A a c i r S s t u U X g G B C R and F partly."
 213   (if ls-lisp-use-insert-directory-program
 214       (funcall original-insert-directory
 215                file switches wildcard full-directory-p)
 216     ;; We need the directory in order to find the right handler.
 217     (let ((handler (find-file-name-handler (expand-file-name file)
 218                                            'insert-directory))
 219           wildcard-regexp)
 220       (if handler
 221           (funcall handler 'insert-directory file switches
 222                    wildcard full-directory-p)
 223         ;; Remove --dired switch
 224         (if (string-match "--dired " switches)
 225             (setq switches (replace-match "" nil nil switches)))
 226         ;; Convert SWITCHES to a list of characters.
 227         (setq switches (delete ?- (append switches nil)))
 228         ;; Sometimes we get ".../foo*/" as FILE.  While the shell and
 229         ;; `ls' don't mind, we certainly do, because it makes us think
 230         ;; there is no wildcard, only a directory name.
 231         (if (and ls-lisp-support-shell-wildcards
 232                  (string-match "[[?*]" file)
 233                  ;; Prefer an existing directory to wildcards, like
 234                  ;; dired-noselect does.
 235                  (not (file-directory-p file)))
 236             (progn
 237               (or (not (eq (aref file (1- (length file))) ?/))
 238                   (setq file (substring file 0 (1- (length file)))))
 239               (setq wildcard t)))
 240         (if wildcard
 241             (setq wildcard-regexp
 242                   (if ls-lisp-support-shell-wildcards
 243                       (wildcard-to-regexp (file-name-nondirectory file))
 244                     (file-name-nondirectory file))
 245                   file (file-name-directory file))
 246           (if (memq ?B switches) (setq wildcard-regexp "[^~]\\'")))
 247         (ls-lisp-insert-directory
 248          file switches (ls-lisp-time-index switches)
 249          wildcard-regexp full-directory-p)
 250         ;; Try to insert the amount of free space.
 251         (save-excursion
 252           (goto-char (point-min))
 253           ;; First find the line to put it on.
 254           (when (re-search-forward "^total" nil t)
 255             (let ((available (get-free-disk-space ".")))
 256               (when available
 257                 ;; Replace "total" with "total used", to avoid confusion.
 258                 (replace-match "total used in directory")
 259                 (end-of-line)
 260                 (insert " available " available)))))))))
 261
 262 (defun ls-lisp-insert-directory
 263   (file switches time-index wildcard-regexp full-directory-p)
 264   "Insert directory listing for FILE, formatted according to SWITCHES.
 265 Leaves point after the inserted text.  This is an internal function
 266 optionally called by the `ls-lisp.el' version of `insert-directory'.
 267 It is called recursively if the -R switch is used.
 268 SWITCHES is a *list* of characters.  TIME-INDEX is the time index into
 269 file-attributes according to SWITCHES.  WILDCARD-REGEXP is nil or an *Emacs
 270 regexp*.  FULL-DIRECTORY-P means file is a directory and SWITCHES does
 271 not contain `d', so that a full listing is expected."
 272   (if (or wildcard-regexp full-directory-p)
 273       (let* ((dir (file-name-as-directory file))
 274              (default-directory dir)    ; so that file-attributes works
 275              (file-alist
 276               (directory-files-and-attributes dir nil wildcard-regexp t 'string))
 277              (now (current-time))
 278              (sum 0)
 279              ;; do all bindings here for speed
 280              total-line files elt short file-size fil attr)
 281         (cond ((memq ?A switches)
 282                (setq file-alist
 283                      (ls-lisp-delete-matching "^\\.\\.?$" file-alist)))
 284               ((not (memq ?a switches))
 285                ;; if neither -A  nor -a, flush . files
 286                (setq file-alist
 287                      (ls-lisp-delete-matching "^\\." file-alist))))
 288         (setq file-alist
 289               (ls-lisp-handle-switches file-alist switches))
 290         (if (memq ?C switches)          ; column (-C) format
 291             (ls-lisp-column-format file-alist)
 292           (setq total-line (cons (point) (car-safe file-alist)))
 293           (setq files file-alist)
 294           (while files                  ; long (-l) format
 295             (setq elt (car files)
 296                   files (cdr files)
 297                   short (car elt)
 298                   attr (cdr elt)
 299                   file-size (nth 7 attr))
 300             (and attr
 301                  (setq sum (+ file-size
 302                               ;; Even if neither SUM nor file's size
 303                               ;; overflow, their sum could.
 304                               (if (or (< sum (- 134217727 file-size))
 305                                       (floatp sum)
 306                                       (floatp file-size))
 307                                   sum
 308                                 (float sum))))
 309                  (insert (ls-lisp-format short attr file-size
 310                                          switches time-index now))))
 311           ;; Insert total size of all files:
 312           (save-excursion
 313             (goto-char (car total-line))
 314             (or (cdr total-line)
 315                 ;; Shell says ``No match'' if no files match
 316                 ;; the wildcard; let's say something similar.
 317                 (insert "(No match)\n"))
 318             (insert (format "total %.0f\n" (fceiling (/ sum 1024.0))))))
 319         (if (memq ?R switches)
 320             ;; List the contents of all directories recursively.
 321             ;; cadr of each element of `file-alist' is t for
 322             ;; directory, string (name linked to) for symbolic
 323             ;; link, or nil.
 324             (while file-alist
 325               (setq elt (car file-alist)
 326                     file-alist (cdr file-alist))
 327               (when (and (eq (cadr elt) t) ; directory
 328                          (not (string-match "\\`\\.\\.?\\'" (car elt))))
 329                 (setq elt (expand-file-name (car elt) dir))
 330                 (insert "\n" elt ":\n")
 331                 (ls-lisp-insert-directory
 332                  elt switches time-index wildcard-regexp full-directory-p)))))
 333     ;; If not full-directory-p, FILE *must not* end in /, as
 334     ;; file-attributes will not recognize a symlink to a directory,
 335     ;; so must make it a relative filename as ls does:
 336     (if (eq (aref file (1- (length file))) ?/)
 337         (setq file (substring file 0 -1)))
 338     (let ((fattr (file-attributes file 'string)))
 339       (if fattr
 340           (insert (ls-lisp-format file fattr (nth 7 fattr)
 341                                   switches time-index (current-time)))
 342         (message "%s: doesn't exist or is inaccessible" file)
 343         (ding) (sit-for 2)))))          ; to show user the message!
 344
 345 (defun ls-lisp-column-format (file-alist)
 346   "Insert the file names (only) in FILE-ALIST into the current buffer.
 347 Format in columns, sorted vertically, following GNU ls -C.
 348 Responds to the window width as ls should but may not!"
 349   (let (files fmt ncols collen (nfiles 0) (colwid 0))
 350     ;; Count number of files as `nfiles', build list of filenames as
 351     ;; `files', and find maximum filename length as `colwid':
 352     (let (file len)
 353       (while file-alist
 354         (setq nfiles (1+ nfiles)
 355               file (caar file-alist)
 356               files (cons file files)
 357               file-alist (cdr file-alist)
 358               len (length file))
 359         (if (> len colwid) (setq colwid len))))
 360     (setq files (nreverse files)
 361           colwid (+ 2 colwid)           ; 2 character column gap
 362           fmt (format "%%-%ds" colwid)  ; print format
 363           ncols (/ (window-width) colwid) ; no of columns
 364           collen (/ nfiles ncols))      ; floor of column length
 365     (if (> nfiles (* collen ncols)) (setq collen (1+ collen)))
 366     ;; Output the file names in columns, sorted vertically:
 367     (let ((i 0) j)
 368       (while (< i collen)
 369         (setq j i)
 370         (while (< j nfiles)
 371           (insert (format fmt (nth j files)))
 372           (setq j (+ j collen)))
 373         ;; FJW: This is completely unnecessary, but I don't like
 374         ;; trailing white space...
 375         (delete-region (point) (progn (skip-chars-backward " \t") (point)))
 376         (insert ?\n)
 377         (setq i (1+ i))))))
 378
 379 (defun ls-lisp-delete-matching (regexp list)
 380   "Delete all elements matching REGEXP from LIST, return new list."
 381   ;; Should perhaps use setcdr for efficiency.
 382   (let (result)
 383     (while list
 384       (or (string-match regexp (caar list))
 385           (setq result (cons (car list) result)))
 386       (setq list (cdr list)))
 387     result))
 388
 389 (defsubst ls-lisp-string-lessp (s1 s2)
 390   "Return t if string S1 is less than string S2 in lexicographic order.
 391 Case is significant if `ls-lisp-ignore-case' is nil.
 392 Unibyte strings are converted to multibyte for comparison."
 393   (let ((u (compare-strings s1 0 nil s2 0 nil ls-lisp-ignore-case)))
 394     (and (numberp u) (< u 0))))
 395
 396 (defun ls-lisp-handle-switches (file-alist switches)
 397   "Return new FILE-ALIST sorted according to SWITCHES.
 398 SWITCHES is a list of characters.  Default sorting is alphabetic."
 399   ;; FILE-ALIST's elements are (FILE . FILE-ATTRIBUTES).
 400   (or (memq ?U switches)                ; unsorted
 401       ;; Catch and ignore unexpected sorting errors
 402       (condition-case err
 403           (setq file-alist
 404                 (let (index)
 405                   ;; Copy file-alist in case of error
 406                   (sort (copy-sequence file-alist) ; modifies its argument!
 407                         (cond ((memq ?S switches)
 408                                (lambda (x y) ; sorted on size
 409                                  ;; 7th file attribute is file size
 410                                  ;; Make largest file come first
 411                                  (< (nth 7 (cdr y))
 412                                     (nth 7 (cdr x)))))
 413                               ((setq index (ls-lisp-time-index switches))
 414                                (lambda (x y) ; sorted on time
 415                                  (ls-lisp-time-lessp (nth index (cdr y))
 416                                                      (nth index (cdr x)))))
 417                               ((memq ?X switches)
 418                                (lambda (x y) ; sorted on extension
 419                                  (ls-lisp-string-lessp
 420                                   (ls-lisp-extension (car x))
 421                                   (ls-lisp-extension (car y)))))
 422                               (t
 423                                (lambda (x y) ; sorted alphabetically
 424                                  (ls-lisp-string-lessp (car x) (car y))))))))
 425         (error (message "Unsorted (ls-lisp sorting error) - %s"
 426                         (error-message-string err))
 427                (ding) (sit-for 2))))    ; to show user the message!
 428   (if (memq ?F switches)                ; classify switch
 429       (setq file-alist (mapcar 'ls-lisp-classify file-alist)))
 430   (if ls-lisp-dirs-first
 431   ;; Re-sort directories first, without otherwise changing the
 432   ;; ordering, and reverse whole list.  cadr of each element of
 433   ;; `file-alist' is t for directory, string (name linked to) for
 434   ;; symbolic link, or nil.
 435       (let (el dirs files)
 436         (while file-alist
 437           (if (or (eq (cadr (setq el (car file-alist))) t) ; directory
 438                   (and (stringp (cadr el))
 439                        (file-directory-p (cadr el)))) ; symlink to a directory
 440               (setq dirs (cons el dirs))
 441             (setq files (cons el files)))
 442           (setq file-alist (cdr file-alist)))
 443         (setq file-alist
 444               (if (memq ?U switches)    ; unsorted order is reversed
 445                   (nconc dirs files)
 446                 (nconc files dirs)
 447                 ))))
 448   ;; Finally reverse file alist if necessary.
 449   ;; (eq below MUST compare `(not (memq ...))' to force comparison of
 450   ;; `t' or `nil', rather than list tails!)
 451   (if (eq (eq (not (memq ?U switches))  ; unsorted order is reversed
 452               (not (memq ?r switches))) ; reversed sort order requested
 453           ls-lisp-dirs-first)           ; already reversed
 454       (nreverse file-alist)
 455     file-alist))
 456
 457 (defun ls-lisp-classify (filedata)
 458   "Append a character to each file name indicating the file type.
 459 Also, for regular files that are executable, append `*'.
 460 The file type indicators are `/' for directories, `@' for symbolic
 461 links, `|' for FIFOs, `=' for sockets, and nothing for regular files.
 462 \[But FIFOs and sockets are not recognized.]
 463 FILEDATA has the form (filename . `file-attributes').  Its `cadr' is t
 464 for directory, string (name linked to) for symbolic link, or nil."
 465   (let ((file-name (car filedata))
 466         (type (cadr filedata)))
 467     (cond (type
 468            (cons
 469             (concat file-name (if (eq type t) "/" "@"))
 470             (cdr filedata)))
 471           ((string-match "x" (nth 9 filedata))
 472            (cons
 473             (concat file-name "*")
 474             (cdr filedata)))
 475           (t filedata))))
 476
 477 (defun ls-lisp-extension (filename)
 478   "Return extension of FILENAME (ignoring any version extension)
 479 FOLLOWED by null and full filename, SOLELY for full alpha sort."
 480   ;; Force extension sort order: `no ext' then `null ext' then `ext'
 481   ;; to agree with GNU ls.
 482   (concat
 483    (let* ((i (length filename)) end)
 484      (if (= (aref filename (1- i)) ?.) ; null extension
 485          "\0"
 486        (while (and (>= (setq i (1- i)) 0)
 487                    (/= (aref filename i) ?.)))
 488        (if (< i 0) "\0\0"               ; no extension
 489          (if (/= (aref filename (1+ i)) ?~)
 490              (substring filename (1+ i))
 491            ;; version extension found -- ignore it
 492            (setq end i)
 493            (while (and (>= (setq i (1- i)) 0)
 494                        (/= (aref filename i) ?.)))
 495            (if (< i 0) "\0\0"   ; no extension
 496              (substring filename (1+ i) end))))
 497        )) "\0" filename))
 498
 499 ;; From Roland McGrath.  Can use this to sort on time.
 500 (defun ls-lisp-time-lessp (time0 time1)
 501   "Return t if time TIME0 is earlier than time TIME1."
 502   (let ((hi0 (car time0)) (hi1 (car time1)))
 503     (or (< hi0 hi1)
 504         (and (= hi0 hi1)
 505              (< (cadr time0) (cadr time1))))))
 506
 507 (defun ls-lisp-format (file-name file-attr file-size switches time-index now)
 508   "Format one line of long ls output for file FILE-NAME.
 509 FILE-ATTR and FILE-SIZE give the file's attributes and size.
 510 SWITCHES, TIME-INDEX and NOW give the full switch list and time data."
 511   (let ((file-type (nth 0 file-attr))
 512         ;; t for directory, string (name linked to)
 513         ;; for symbolic link, or nil.
 514         (drwxrwxrwx (nth 8 file-attr))) ; attribute string ("drwxrwxrwx")
 515     (concat (if (memq ?i switches)      ; inode number
 516                 (format " %6d" (nth 10 file-attr)))
 517             ;; nil is treated like "" in concat
 518             (if (memq ?s switches)      ; size in K
 519                 (format " %4.0f" (fceiling (/ file-size 1024.0))))
 520             drwxrwxrwx                  ; attribute string
 521             (if (memq 'links ls-lisp-verbosity)
 522                 (format " %3d" (nth 1 file-attr))) ; link count
 523             ;; Numeric uid/gid are more confusing than helpful;
 524             ;; Emacs should be able to make strings of them.
 525             ;; They tend to be bogus on non-UNIX platforms anyway so
 526             ;; optionally hide them.
 527             (if (memq 'uid ls-lisp-verbosity)
 528                 ;; uid can be a sting or an integer
 529                 (let ((uid (nth 2 file-attr)))
 530                   (format (if (stringp uid) " %-8s" " %-8d") uid)))
 531             (if (not (memq ?G switches)) ; GNU ls -- shows group by default
 532                 (if (or (memq ?g switches) ; UNIX ls -- no group by default
 533                         (memq 'gid ls-lisp-verbosity))
 534                     (let ((gid (nth 3 file-attr)))
 535                       (format (if (stringp gid) " %-8s" " %-8d") gid))))
 536             (ls-lisp-format-file-size file-size (memq ?h switches))
 537             " "
 538             (ls-lisp-format-time file-attr time-index now)
 539             " "
 540             (propertize file-name 'dired-filename t)
 541             (if (stringp file-type)     ; is a symbolic link
 542                 (concat " -> " file-type))
 543             "\n"
 544             )))
 545
 546 (defun ls-lisp-time-index (switches)
 547   "Return time index into file-attributes according to ls SWITCHES list.
 548 Return nil if no time switch found."
 549   ;; FJW: Default of nil is IMPORTANT and used in `ls-lisp-handle-switches'!
 550   (cond ((memq ?c switches) 6)          ; last mode change
 551         ((memq ?t switches) 5)          ; last modtime
 552         ((memq ?u switches) 4)))        ; last access
 553
 554 (defun ls-lisp-time-to-seconds (time)
 555   "Convert TIME to a floating point number."
 556   (+ (* (car time) 65536.0)
 557      (cadr time)
 558      (/ (or (nth 2 time) 0) 1000000.0)))
 559
 560 (defun ls-lisp-format-time (file-attr time-index now)
 561   "Format time for file with attributes FILE-ATTR according to TIME-INDEX.
 562 Use the same method as ls to decide whether to show time-of-day or year,
 563 depending on distance between file date and NOW.
 564 All ls time options, namely c, t and u, are handled."
 565   (let* ((time (nth (or time-index 5) file-attr)) ; default is last modtime
 566          (diff (- (ls-lisp-time-to-seconds time)
 567                   (ls-lisp-time-to-seconds now)))
 568          ;; Consider a time to be recent if it is within the past six
 569          ;; months.  A Gregorian year has 365.2425 * 24 * 60 * 60 ==
 570          ;; 31556952 seconds on the average, and half of that is 15778476.
 571          ;; Write the constant explicitly to avoid roundoff error.
 572          (past-cutoff -15778476)) ; half a Gregorian year
 573     (condition-case nil
 574         ;; Use traditional time format in the C or POSIX locale,
 575         ;; ISO-style time format otherwise, so columns line up.
 576         (let ((locale system-time-locale))
 577           (if (not locale)
 578               (let ((vars '("LC_ALL" "LC_TIME" "LANG")))
 579                 (while (and vars (not (setq locale (getenv (car vars)))))
 580                   (setq vars (cdr vars)))))
 581           (if (member locale '("C" "POSIX"))
 582               (setq locale nil))
 583           (format-time-string
 584            (if (and (<= past-cutoff diff) (<= diff 0))
 585                (if (and locale (not ls-lisp-use-localized-time-format))
 586                    "%m-%d %H:%M"
 587                  (nth 0 ls-lisp-format-time-list))
 588              (if (and locale (not ls-lisp-use-localized-time-format))
 589                  "%Y-%m-%d "
 590                (nth 1 ls-lisp-format-time-list)))
 591            time))
 592       (error "Unk  0  0000"))))
 593
 594 (defun ls-lisp-format-file-size (file-size human-readable)
 595   (if (or (not human-readable)
 596           (< file-size 1024))
 597       (format (if (floatp file-size) " %9.0f" " %9d") file-size)
 598     (do ((file-size (/ file-size 1024.0) (/ file-size 1024.0))
 599          ;; kilo, mega, giga, tera, peta, exa
 600          (post-fixes (list "k" "M" "G" "T" "P" "E") (cdr post-fixes)))
 601         ((< file-size 1024) (format " %8.0f%s"  file-size (car post-fixes))))))
 602
 603 (provide 'ls-lisp)
 604
 605 ;;; arch-tag: e55f399b-05ec-425c-a6d5-f5e349c35ab4
 606 ;;; ls-lisp.el ends here