lisp/tar-mode.el

   1 ;;; tar-mode.el --- simple editing of tar files from GNU emacs
   2
   3 ;;; Copyright (C) 1990, 1991, 1993, 1994 Free Software Foundation, Inc.
   4
   5 ;; Author: Jamie Zawinski <jwz@lucid.com>
   6 ;; Created: 04 Apr 1990
   7 ;; Keywords: unix
   8
   9 ;;; This file is part of GNU Emacs.
  10 ;;;
  11 ;;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;;; it under the terms of the GNU General Public License as published by
  13 ;;; the Free Software Foundation; either version 2, or (at your option)
  14 ;;; any later version.
  15 ;;;
  16 ;;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;;; GNU General Public License for more details.
  20 ;;;
  21 ;;; You should have received a copy of the GNU General Public License
  22 ;;; along with GNU Emacs; see the file COPYING.  If not, write to
  23 ;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Commentary:
  26
  27 ;;; This package attempts to make dealing with Unix 'tar' archives easier.
  28 ;;; When this code is loaded, visiting a file whose name ends in '.tar' will
  29 ;;; cause the contents of that archive file to be displayed in a Dired-like
  30 ;;; listing.  It is then possible to use the customary Dired keybindings to
  31 ;;; extract sub-files from that archive, either by reading them into their own
  32 ;;; editor buffers, or by copying them directly to arbitrary files on disk.
  33 ;;; It is also possible to delete sub-files from within the tar file and write
  34 ;;; the modified archive back to disk, or to edit sub-files within the archive
  35 ;;; and re-insert the modified files into the archive.  See the documentation
  36 ;;; string of tar-mode for more info.
  37
  38 ;;; This code now understands the extra fields that GNU tar adds to tar files.
  39
  40 ;;; This interacts correctly with "uncompress.el" in the Emacs library,
  41 ;;; which you get with
  42 ;;;
  43 ;;;  (autoload 'uncompress-while-visiting "uncompress")
  44 ;;;  (setq auto-mode-alist (cons '("\\.Z$" . uncompress-while-visiting)
  45 ;;;                        auto-mode-alist))
  46 ;;;
  47 ;;; Do not attempt to use tar-mode.el with crypt.el, you will lose.
  48
  49 ;;;    ***************   TO DO   ***************
  50 ;;;
  51 ;;; o  chmod should understand "a+x,og-w".
  52 ;;;
  53 ;;; o  It's not possible to add a NEW file to a tar archive; not that
  54 ;;;    important, but still...
  55 ;;;
  56 ;;; o  The code is less efficient that it could be - in a lot of places, I
  57 ;;;    pull a 512-character string out of the buffer and parse it, when I could
  58 ;;;    be parsing it in place, not garbaging a string.  Should redo that.
  59 ;;;
  60 ;;; o  I'd like a command that searches for a string/regexp in every subfile
  61 ;;;    of an archive, where <esc> would leave you in a subfile-edit buffer.
  62 ;;;    (Like the Meta-R command of the Zmacs mail reader.)
  63 ;;;
  64 ;;; o  Sometimes (but not always) reverting the tar-file buffer does not
  65 ;;;    re-grind the listing, and you are staring at the binary tar data.
  66 ;;;    Typing 'g' again immediately after that will always revert and re-grind
  67 ;;;    it, though.  I have no idea why this happens.
  68 ;;;
  69 ;;; o  Tar-mode interacts poorly with crypt.el and zcat.el because the tar
  70 ;;;    write-file-hook actually writes the file.  Instead it should remove the
  71 ;;;    header (and conspire to put it back afterwards) so that other write-file
  72 ;;;    hooks which frob the buffer have a chance to do their dirty work.  There
  73 ;;;    might be a problem if the tar write-file-hook does not come *first* on
  74 ;;;    the list.
  75 ;;;
  76 ;;; o  Block files, sparse files, continuation files, and the various header
  77 ;;;    types aren't editable.  Actually I don't know that they work at all.
  78
  79 ;;; Rationale:
  80
  81 ;;; Why does tar-mode edit the file itself instead of using tar?
  82
  83 ;;; That means that you can edit tar files which you don't have room for
  84 ;;; on your local disk.
  85
  86 ;;; I don't know about recent features in gnu tar, but old versions of tar
  87 ;;; can't replace a file in the middle of a tar file with a new version.
  88 ;;; Tar-mode can.  I don't think tar can do things like chmod the subfiles.
  89 ;;; An implementation which involved unpacking and repacking the file into
  90 ;;; some scratch directory would be very wasteful, and wouldn't be able to
  91 ;;; preserve the file owners.
  92
  93 ;;; Code:
  94
  95 (defvar tar-anal-blocksize 20
  96   "*The blocksize of tar files written by Emacs, or nil, meaning don't care.
  97 The blocksize of a tar file is not really the size of the blocks; rather, it is
  98 the number of blocks written with one system call.  When tarring to a tape,
  99 this is the size of the *tape* blocks, but when writing to a file, it doesn't
 100 matter much.  The only noticeable difference is that if a tar file does not
 101 have a blocksize of 20, tar will tell you that; all this really controls is
 102 how many null padding bytes go on the end of the tar file.")
 103
 104 (defvar tar-update-datestamp nil
 105   "*Non-nil means tar-mode should play fast and loose with sub-file datestamps.
 106 If this is true, then editing and saving a tar file entry back into its
 107 tar file will update its datestamp.  If false, the datestamp is unchanged.
 108 You may or may not want this - it is good in that you can tell when a file
 109 in a tar archive has been changed, but it is bad for the same reason that
 110 editing a file in the tar archive at all is bad - the changed version of
 111 the file never exists on disk.")
 112
 113 (defvar tar-mode-show-date nil
 114   "*Non-nil means Tar mode should show the date/time of each subfile.
 115 This information is useful, but it takes screen space away from file names.")
 116
 117 (defvar tar-parse-info nil)
 118 (defvar tar-header-offset nil)
 119 (defvar tar-superior-buffer nil)
 120 (defvar tar-superior-descriptor nil)
 121 (defvar tar-subfile-mode nil)
 122
 123 (put 'tar-parse-info 'permanent-local t)
 124 (put 'tar-header-offset 'permanent-local t)
 125 (put 'tar-superior-buffer 'permanent-local t)
 126 (put 'tar-superior-descriptor 'permanent-local t)
 127 \f
 128 ;;; First, duplicate some Common Lisp functions; I used to just (require 'cl)
 129 ;;; but "cl.el" was messing some people up (also it's really big).
 130
 131 (defmacro tar-setf (form val)
 132   "A mind-numbingly simple implementation of setf."
 133   (let ((mform (macroexpand form (and (boundp 'byte-compile-macro-environment)
 134                                       byte-compile-macro-environment))))
 135     (cond ((symbolp mform) (list 'setq mform val))
 136           ((not (consp mform)) (error "can't setf %s" form))
 137           ((eq (car mform) 'aref)
 138            (list 'aset (nth 1 mform) (nth 2 mform) val))
 139           ((eq (car mform) 'car)
 140            (list 'setcar (nth 1 mform) val))
 141           ((eq (car mform) 'cdr)
 142            (list 'setcdr (nth 1 mform) val))
 143           (t (error "don't know how to setf %s" form)))))
 144
 145 (defmacro tar-dolist (control &rest body)
 146   "syntax: (dolist (var-name list-expr &optional return-value) &body body)"
 147   (let ((var (car control))
 148         (init (car (cdr control)))
 149         (val (car (cdr (cdr control)))))
 150     (list 'let (list (list '_dolist_iterator_ init))
 151           (list 'while '_dolist_iterator_
 152             (cons 'let
 153               (cons (list (list var '(car _dolist_iterator_)))
 154                     (append body
 155                             (list (list 'setq '_dolist_iterator_
 156                                         (list 'cdr '_dolist_iterator_)))))))
 157           val)))
 158
 159 (defmacro tar-dotimes (control &rest body)
 160   "syntax: (dolist (var-name count-expr &optional return-value) &body body)"
 161   (let ((var (car control))
 162         (n (car (cdr control)))
 163         (val (car (cdr (cdr control)))))
 164     (list 'let (list (list '_dotimes_end_ n)
 165                      (list var 0))
 166           (cons 'while
 167                 (cons (list '< var '_dotimes_end_)
 168                       (append body
 169                               (list (list 'setq var (list '1+ var))))))
 170           val)))
 171
 172 \f
 173 ;;; down to business.
 174
 175 (defmacro make-tar-header (name mode uid git size date ck lt ln
 176                            magic uname gname devmaj devmin)
 177   (list 'vector name mode uid git size date ck lt ln
 178         magic uname gname devmaj devmin))
 179
 180 (defmacro tar-header-name (x) (list 'aref x 0))
 181 (defmacro tar-header-mode (x) (list 'aref x 1))
 182 (defmacro tar-header-uid  (x) (list 'aref x 2))
 183 (defmacro tar-header-gid  (x) (list 'aref x 3))
 184 (defmacro tar-header-size (x) (list 'aref x 4))
 185 (defmacro tar-header-date (x) (list 'aref x 5))
 186 (defmacro tar-header-checksum  (x) (list 'aref x 6))
 187 (defmacro tar-header-link-type (x) (list 'aref x 7))
 188 (defmacro tar-header-link-name (x) (list 'aref x 8))
 189 (defmacro tar-header-magic (x) (list 'aref x 9))
 190 (defmacro tar-header-uname (x) (list 'aref x 10))
 191 (defmacro tar-header-gname (x) (list 'aref x 11))
 192 (defmacro tar-header-dmaj (x) (list 'aref x 12))
 193 (defmacro tar-header-dmin (x) (list 'aref x 13))
 194
 195 (defmacro make-tar-desc (data-start tokens)
 196   (list 'cons data-start tokens))
 197
 198 (defmacro tar-desc-data-start (x) (list 'car x))
 199 (defmacro tar-desc-tokens     (x) (list 'cdr x))
 200
 201 (defconst tar-name-offset 0)
 202 (defconst tar-mode-offset (+ tar-name-offset 100))
 203 (defconst tar-uid-offset  (+ tar-mode-offset 8))
 204 (defconst tar-gid-offset  (+ tar-uid-offset 8))
 205 (defconst tar-size-offset (+ tar-gid-offset 8))
 206 (defconst tar-time-offset (+ tar-size-offset 12))
 207 (defconst tar-chk-offset  (+ tar-time-offset 12))
 208 (defconst tar-linkp-offset (+ tar-chk-offset 8))
 209 (defconst tar-link-offset (+ tar-linkp-offset 1))
 210 ;;; GNU-tar specific slots.
 211 (defconst tar-magic-offset (+ tar-link-offset 100))
 212 (defconst tar-uname-offset (+ tar-magic-offset 8))
 213 (defconst tar-gname-offset (+ tar-uname-offset 32))
 214 (defconst tar-dmaj-offset (+ tar-gname-offset 32))
 215 (defconst tar-dmin-offset (+ tar-dmaj-offset 8))
 216 (defconst tar-end-offset (+ tar-dmin-offset 8))
 217
 218 (defun tar-header-block-tokenize (string)
 219   "Return a `tar-header' structure.
 220 This is a list of name, mode, uid, gid, size,
 221 write-date, checksum, link-type, and link-name."
 222   (cond ((< (length string) 512) nil)
 223         (;(some 'plusp string)           ; <-- oops, massive cycle hog!
 224          (or (not (= 0 (aref string 0))) ; This will do.
 225              (not (= 0 (aref string 101))))
 226          (let* ((name-end (1- tar-mode-offset))
 227                 (link-end (1- tar-magic-offset))
 228                 (uname-end (1- tar-gname-offset))
 229                 (gname-end (1- tar-dmaj-offset))
 230                 (link-p (aref string tar-linkp-offset))
 231                 (magic-str (substring string tar-magic-offset (1- tar-uname-offset)))
 232                 (uname-valid-p (or (string= "ustar  " magic-str) (string= "GNUtar " magic-str)))
 233                 name
 234                 (nulsexp   "[^\000]*\000"))
 235            (and (string-match nulsexp string tar-name-offset) (setq name-end (min name-end (1- (match-end 0)))))
 236            (and (string-match nulsexp string tar-link-offset) (setq link-end (min link-end (1- (match-end 0)))))
 237            (and (string-match nulsexp string tar-uname-offset) (setq uname-end (min uname-end (1- (match-end 0)))))
 238            (and (string-match nulsexp string tar-gname-offset) (setq gname-end (min gname-end (1- (match-end 0)))))
 239            (setq name (substring string tar-name-offset name-end)
 240                  link-p (if (or (= link-p 0) (= link-p ?0))
 241                             nil
 242                           (- link-p ?0)))
 243            (if (and (null link-p) (string-match "/$" name)) (setq link-p 5)) ; directory
 244            (make-tar-header
 245              name
 246              (tar-parse-octal-integer string tar-mode-offset (1- tar-uid-offset))
 247              (tar-parse-octal-integer string tar-uid-offset (1- tar-gid-offset))
 248              (tar-parse-octal-integer string tar-gid-offset (1- tar-size-offset))
 249              (tar-parse-octal-integer string tar-size-offset (1- tar-time-offset))
 250              (tar-parse-octal-long-integer string tar-time-offset (1- tar-chk-offset))
 251              (tar-parse-octal-integer string tar-chk-offset (1- tar-linkp-offset))
 252              link-p
 253              (substring string tar-link-offset link-end)
 254              uname-valid-p
 255              (and uname-valid-p (substring string tar-uname-offset uname-end))
 256              (and uname-valid-p (substring string tar-gname-offset gname-end))
 257              (tar-parse-octal-integer string tar-dmaj-offset (1- tar-dmin-offset))
 258              (tar-parse-octal-integer string tar-dmin-offset (1- tar-end-offset))
 259              )))
 260         (t 'empty-tar-block)))
 261
 262
 263 (defun tar-parse-octal-integer (string &optional start end)
 264   (if (null start) (setq start 0))
 265   (if (null end) (setq end (length string)))
 266   (if (= (aref string start) 0)
 267       0
 268     (let ((n 0))
 269       (while (< start end)
 270         (setq n (if (< (aref string start) ?0) n
 271                   (+ (* n 8) (- (aref string start) ?0)))
 272               start (1+ start)))
 273       n)))
 274
 275 (defun tar-parse-octal-long-integer (string &optional start end)
 276   (if (null start) (setq start 0))
 277   (if (null end) (setq end (length string)))
 278   (if (= (aref string start) 0)
 279       (list 0 0)
 280     (let ((lo 0)
 281           (hi 0))
 282       (while (< start end)
 283         (if (>= (aref string start) ?0)
 284             (setq lo (+ (* lo 8) (- (aref string start) ?0))
 285                   hi (+ (* hi 8) (ash lo -16))
 286                   lo (logand lo 65535)))
 287         (setq start (1+ start)))
 288       (list hi lo))))
 289
 290 (defun tar-parse-octal-integer-safe (string)
 291   (let ((L (length string)))
 292     (if (= L 0) (error "empty string"))
 293     (tar-dotimes (i L)
 294        (if (or (< (aref string i) ?0)
 295                (> (aref string i) ?7))
 296            (error "'%c' is not an octal digit"))))
 297   (tar-parse-octal-integer string))
 298
 299
 300 (defun tar-header-block-checksum (string)
 301   "Compute and return a tar-acceptable checksum for this block."
 302   (let* ((chk-field-start tar-chk-offset)
 303          (chk-field-end (+ chk-field-start 8))
 304          (sum 0)
 305          (i 0))
 306     ;; Add up all of the characters except the ones in the checksum field.
 307     ;; Add that field as if it were filled with spaces.
 308     (while (< i chk-field-start)
 309       (setq sum (+ sum (aref string i))
 310             i (1+ i)))
 311     (setq i chk-field-end)
 312     (while (< i 512)
 313       (setq sum (+ sum (aref string i))
 314             i (1+ i)))
 315     (+ sum (* 32 8))))
 316
 317 (defun tar-header-block-check-checksum (hblock desired-checksum file-name)
 318   "Beep and print a warning if the checksum doesn't match."
 319   (if (not (= desired-checksum (tar-header-block-checksum hblock)))
 320       (progn (beep) (message "Invalid checksum for file %s!" file-name))))
 321
 322 (defun tar-header-block-recompute-checksum (hblock)
 323   "Modifies the given string to have a valid checksum field."
 324   (let* ((chk (tar-header-block-checksum hblock))
 325          (chk-string (format "%6o" chk))
 326          (l (length chk-string)))
 327     (aset hblock 154 0)
 328     (aset hblock 155 32)
 329     (tar-dotimes (i l) (aset hblock (- 153 i) (aref chk-string (- l i 1)))))
 330   hblock)
 331
 332 (defun tar-clip-time-string (time)
 333   (let ((str (current-time-string time)))
 334     (concat (substring str 4 16) (substring str 19 24))))
 335
 336 (defun tar-grind-file-mode (mode string start)
 337   "Store `-rw--r--r--' indicating MODE into STRING beginning at START.
 338 MODE should be an integer which is a file mode value."
 339   (aset string start       (if (zerop (logand 256 mode)) ?- ?r))
 340   (aset string (+ start 1) (if (zerop (logand 128 mode)) ?- ?w))
 341   (aset string (+ start 2) (if (zerop (logand  64 mode)) ?- ?x))
 342   (aset string (+ start 3) (if (zerop (logand  32 mode)) ?- ?r))
 343   (aset string (+ start 4) (if (zerop (logand  16 mode)) ?- ?w))
 344   (aset string (+ start 5) (if (zerop (logand   8 mode)) ?- ?x))
 345   (aset string (+ start 6) (if (zerop (logand   4 mode)) ?- ?r))
 346   (aset string (+ start 7) (if (zerop (logand   2 mode)) ?- ?w))
 347   (aset string (+ start 8) (if (zerop (logand   1 mode)) ?- ?x))
 348   (if (zerop (logand 1024 mode)) nil (aset string (+ start 2) ?s))
 349   (if (zerop (logand 2048 mode)) nil (aset string (+ start 5) ?s))
 350   string)
 351
 352 (defun tar-header-block-summarize (tar-hblock &optional mod-p)
 353   "Returns a line similar to the output of `tar -vtf'."
 354   (let ((name (tar-header-name tar-hblock))
 355         (mode (tar-header-mode tar-hblock))
 356         (uid (tar-header-uid tar-hblock))
 357         (gid (tar-header-gid tar-hblock))
 358         (uname (tar-header-uname tar-hblock))
 359         (gname (tar-header-gname tar-hblock))
 360         (size (tar-header-size tar-hblock))
 361         (time (tar-header-date tar-hblock))
 362         (ck (tar-header-checksum tar-hblock))
 363         (link-p (tar-header-link-type tar-hblock))
 364         (link-name (tar-header-link-name tar-hblock))
 365         )
 366     (let* ((left 11)
 367            (namew 8)
 368            (groupw 8)
 369            (sizew 8)
 370            (datew (if tar-mode-show-date 18 0))
 371            (slash (1- (+ left namew)))
 372            (lastdigit (+ slash groupw sizew))
 373            (datestart (+ lastdigit 2))
 374            (namestart (+ datestart datew))
 375            (string (make-string (+ namestart (length name) (if link-p (+ 5 (length link-name)) 0)) 32))
 376            (type (tar-header-link-type tar-hblock)))
 377       (aset string 0 (if mod-p ?* ? ))
 378       (aset string 1
 379             (cond ((or (eq type nil) (eq type 0)) ?-)
 380                   ((eq type 1) ?l)  ; link
 381                   ((eq type 2) ?s)  ; symlink
 382                   ((eq type 3) ?c)  ; char special
 383                   ((eq type 4) ?b)  ; block special
 384                   ((eq type 5) ?d)  ; directory
 385                   ((eq type 6) ?p)  ; FIFO/pipe
 386                   ((eq type 20) ?*) ; directory listing
 387                   ((eq type 29) ?M) ; multivolume continuation
 388                   ((eq type 35) ?S) ; sparse
 389                   ((eq type 38) ?V) ; volume header
 390                   ))
 391       (tar-grind-file-mode mode string 2)
 392       (setq uid (if (= 0 (length uname)) (int-to-string uid) uname))
 393       (setq gid (if (= 0 (length gname)) (int-to-string gid) gname))
 394       (setq size (int-to-string size))
 395       (setq time (tar-clip-time-string time))
 396       (tar-dotimes (i (min (1- namew) (length uid))) (aset string (- slash i) (aref uid (- (length uid) i 1))))
 397       (aset string (1+ slash) ?/)
 398       (tar-dotimes (i (min (1- groupw) (length gid))) (aset string (+ (+ slash 2) i) (aref gid i)))
 399       (tar-dotimes (i (min sizew (length size))) (aset string (- lastdigit i) (aref size (- (length size) i 1))))
 400       (if tar-mode-show-date
 401           (tar-dotimes (i (length time)) (aset string (+ datestart i) (aref time i))))
 402       (tar-dotimes (i (length name)) (aset string (+ namestart i) (aref name i)))
 403       (if (or (eq link-p 1) (eq link-p 2))
 404           (progn
 405             (tar-dotimes (i 3) (aset string (+ namestart 1 (length name) i) (aref (if (= link-p 1) "==>" "-->") i)))
 406             (tar-dotimes (i (length link-name)) (aset string (+ namestart 5 (length name) i) (aref link-name i)))))
 407       (put-text-property namestart (length string)
 408                          'mouse-face 'highlight string)
 409       string)))
 410
 411
 412 (defun tar-summarize-buffer ()
 413   "Parse the contents of the tar file in the current buffer.
 414 Place a dired-like listing on the front;
 415 then narrow to it, so that only that listing
 416 is visible (and the real data of the buffer is hidden)."
 417   (message "parsing tar file...")
 418   (let* ((result '())
 419          (pos 1)
 420          (bs (max 1 (- (buffer-size) 1024))) ; always 2+ empty blocks at end.
 421          (bs100 (max 1 (/ bs 100)))
 422          tokens)
 423     (while (and (<= (+ pos 512) (point-max))
 424                 (not (eq 'empty-tar-block
 425                          (setq tokens
 426                                (tar-header-block-tokenize
 427                                 (buffer-substring pos (+ pos 512)))))))
 428       (setq pos (+ pos 512))
 429       (message "Parsing tar file...%d%%"
 430                ;(/ (* pos 100) bs)   ; this gets round-off lossage
 431                (/ pos bs100)         ; this doesn't
 432                )
 433       (if (eq (tar-header-link-type tokens) 20)
 434           ;; Foo.  There's an extra empty block after these.
 435           (setq pos (+ pos 512)))
 436       (let ((size (tar-header-size tokens)))
 437         (if (< size 0)
 438             (error "%s has size %s - corrupted"
 439                    (tar-header-name tokens) size))
 440         ;
 441         ; This is just too slow.  Don't really need it anyway....
 442         ;(tar-header-block-check-checksum
 443         ;  hblock (tar-header-block-checksum hblock)
 444         ;  (tar-header-name tokens))
 445
 446         (setq result (cons (make-tar-desc pos tokens) result))
 447
 448         (and (null (tar-header-link-type tokens))
 449              (> size 0)
 450              (setq pos
 451                    (+ pos 512 (ash (ash (1- size) -9) 9))        ; this works
 452                    ;(+ pos (+ size (- 512 (rem (1- size) 512)))) ; this doesn't
 453                    ))))
 454     (make-local-variable 'tar-parse-info)
 455     (setq tar-parse-info (nreverse result))
 456     ;; A tar file should end with a block or two of nulls,
 457     ;; but let's not get a fatal error if it doesn't.
 458     (if (eq tokens 'empty-tar-block)
 459         (message "Parsing tar file...done.")
 460       (message "Warning: premature EOF parsing tar file")))
 461   (save-excursion
 462     (goto-char (point-min))
 463     (let ((buffer-read-only nil))
 464       (tar-dolist (tar-desc tar-parse-info)
 465         (insert-string
 466           (tar-header-block-summarize (tar-desc-tokens tar-desc)))
 467         (insert-string "\n"))
 468       (make-local-variable 'tar-header-offset)
 469       (setq tar-header-offset (point))
 470       (narrow-to-region 1 tar-header-offset)
 471       (set-buffer-modified-p nil))))
 472 \f
 473 (defvar tar-mode-map nil "*Local keymap for Tar mode listings.")
 474
 475 (if tar-mode-map
 476     nil
 477   (setq tar-mode-map (make-keymap))
 478   (suppress-keymap tar-mode-map)
 479   (define-key tar-mode-map " " 'tar-next-line)
 480   (define-key tar-mode-map "c" 'tar-copy)
 481   (define-key tar-mode-map "d" 'tar-flag-deleted)
 482   (define-key tar-mode-map "\^D" 'tar-flag-deleted)
 483   (define-key tar-mode-map "e" 'tar-extract)
 484   (define-key tar-mode-map "f" 'tar-extract)
 485   (define-key tar-mode-map "\C-m" 'tar-extract)
 486   (define-key tar-mode-map [mouse-2] 'tar-mouse-extract)
 487   (define-key tar-mode-map "g" 'revert-buffer)
 488   (define-key tar-mode-map "h" 'describe-mode)
 489   (define-key tar-mode-map "n" 'tar-next-line)
 490   (define-key tar-mode-map "\^N" 'tar-next-line)
 491   (define-key tar-mode-map "o" 'tar-extract-other-window)
 492   (define-key tar-mode-map "p" 'tar-previous-line)
 493   (define-key tar-mode-map "\^P" 'tar-previous-line)
 494   (define-key tar-mode-map "r" 'tar-rename-entry)
 495   (define-key tar-mode-map "u" 'tar-unflag)
 496   (define-key tar-mode-map "v" 'tar-view)
 497   (define-key tar-mode-map "x" 'tar-expunge)
 498   (define-key tar-mode-map "\177" 'tar-unflag-backwards)
 499   (define-key tar-mode-map "E" 'tar-extract-other-window)
 500   (define-key tar-mode-map "M" 'tar-chmod-entry)
 501   (define-key tar-mode-map "G" 'tar-chgrp-entry)
 502   (define-key tar-mode-map "O" 'tar-chown-entry)
 503   )
 504 \f
 505 ;; Make menu bar items.
 506
 507 ;; Get rid of the Edit menu bar item to save space.
 508 (define-key tar-mode-map [menu-bar edit] 'undefined)
 509
 510 (define-key tar-mode-map [menu-bar immediate]
 511   (cons "Immediate" (make-sparse-keymap "Immediate")))
 512
 513 (define-key tar-mode-map [menu-bar immediate view]
 514   '("View This File" . tar-view))
 515 (define-key tar-mode-map [menu-bar immediate display]
 516   '("Display in Other Window" . tar-display-other-file))
 517 (define-key tar-mode-map [menu-bar immediate find-file-other-window]
 518   '("Find in Other Window" . tar-extract-other-window))
 519 (define-key tar-mode-map [menu-bar immediate find-file]
 520   '("Find This File" . tar-extract))
 521
 522 (define-key tar-mode-map [menu-bar mark]
 523   (cons "Mark" (make-sparse-keymap "Mark")))
 524
 525 (define-key tar-mode-map [menu-bar mark unmark-all]
 526   '("Unmark All" . tar-clear-modification-flags))
 527 (define-key tar-mode-map [menu-bar mark deletion]
 528   '("Flag" . tar-flag-deleted))
 529 (define-key tar-mode-map [menu-bar mark unmark]
 530   '("Unflag" . tar-unflag))
 531
 532 (define-key tar-mode-map [menu-bar operate]
 533   (cons "Operate" (make-sparse-keymap "Operate")))
 534
 535 (define-key tar-mode-map [menu-bar operate chown]
 536   '("Change Owner..." . tar-chown-entry))
 537 (define-key tar-mode-map [menu-bar operate chgrp]
 538   '("Change Group..." . tar-chgrp-entry))
 539 (define-key tar-mode-map [menu-bar operate chmod]
 540   '("Change Mode..." . tar-chmod-entry))
 541 (define-key tar-mode-map [menu-bar operate rename]
 542   '("Rename to..." . tar-rename-entry))
 543 (define-key tar-mode-map [menu-bar operate copy]
 544   '("Copy to..." . tar-copy))
 545 (define-key tar-mode-map [menu-bar operate expunge]
 546   '("Expunge marked files" . tar-expunge))
 547 \f
 548 ;; tar mode is suitable only for specially formatted data.
 549 (put 'tar-mode 'mode-class 'special)
 550 (put 'tar-subfile-mode 'mode-class 'special)
 551
 552 ;;;###autoload
 553 (defun tar-mode ()
 554   "Major mode for viewing a tar file as a dired-like listing of its contents.
 555 You can move around using the usual cursor motion commands.
 556 Letters no longer insert themselves.
 557 Type `e' to pull a file out of the tar file and into its own buffer;
 558 or click mouse-2 on the file's line in the Tar mode buffer.
 559 Type `c' to copy an entry from the tar file into another file on disk.
 560
 561 If you edit a sub-file of this archive (as with the `e' command) and
 562 save it with Control-x Control-s, the contents of that buffer will be
 563 saved back into the tar-file buffer; in this way you can edit a file
 564 inside of a tar archive without extracting it and re-archiving it.
 565
 566 See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
 567 \\{tar-mode-map}"
 568   ;; this is not interactive because you shouldn't be turning this
 569   ;; mode on and off.  You can corrupt things that way.
 570   ;; rms: with permanent locals, it should now be possible to make this work
 571   ;; interactively in some reasonable fashion.
 572   (kill-all-local-variables)
 573   (make-local-variable 'tar-header-offset)
 574   (make-local-variable 'tar-parse-info)
 575   (make-local-variable 'require-final-newline)
 576   (setq require-final-newline nil) ; binary data, dude...
 577   (make-local-variable 'revert-buffer-function)
 578   (setq revert-buffer-function 'tar-mode-revert)
 579   (make-local-variable 'enable-local-variables)
 580   (setq enable-local-variables nil)
 581   (setq major-mode 'tar-mode)
 582   (setq mode-name "Tar")
 583   (use-local-map tar-mode-map)
 584   (auto-save-mode 0)
 585   (widen)
 586   (if (and (boundp 'tar-header-offset) tar-header-offset)
 587       (narrow-to-region 1 tar-header-offset)
 588       (tar-summarize-buffer))
 589   (run-hooks 'tar-mode-hook)
 590   )
 591
 592
 593 ;; This should be converted to use a minor mode keymap.
 594
 595 (defun tar-subfile-mode (p)
 596   "Minor mode for editing an element of a tar-file.
 597 This mode redefines C-x C-s to save the current buffer back into its
 598 associated tar-file buffer.  You must save that buffer to actually
 599 save your changes to disk."
 600   (interactive "P")
 601   (or (and (boundp 'tar-superior-buffer) tar-superior-buffer)
 602       (error "This buffer is not an element of a tar file"))
 603 ;;; Don't do this, because it is redundant and wastes mode line space.
 604 ;;;  (or (assq 'tar-subfile-mode minor-mode-alist)
 605 ;;;      (setq minor-mode-alist (append minor-mode-alist
 606 ;;;                                  (list '(tar-subfile-mode " TarFile")))))
 607   (make-local-variable 'tar-subfile-mode)
 608   (setq tar-subfile-mode
 609         (if (null p)
 610             (not tar-subfile-mode)
 611             (> (prefix-numeric-value p) 0)))
 612   (cond (tar-subfile-mode
 613          (make-local-variable 'local-write-file-hooks)
 614          (setq local-write-file-hooks '(tar-subfile-save-buffer))
 615          ;; turn off auto-save.
 616          (auto-save-mode nil)
 617          (setq buffer-auto-save-file-name nil)
 618          (run-hooks 'tar-subfile-mode-hook))
 619         (t
 620          (kill-local-variable 'local-write-file-hooks))))
 621
 622
 623 ;; Revert the buffer and recompute the dired-like listing.
 624 (defun tar-mode-revert (&optional no-autosave no-confirm)
 625   (setq tar-header-offset nil)
 626   (let ((revert-buffer-function nil))
 627     (revert-buffer t no-confirm)
 628     (widen))
 629   (tar-mode))
 630
 631
 632 (defun tar-next-line (p)
 633   (interactive "p")
 634   (forward-line p)
 635   (if (eobp) nil (forward-char (if tar-mode-show-date 54 36))))
 636
 637 (defun tar-previous-line (p)
 638   (interactive "p")
 639   (tar-next-line (- p)))
 640
 641 (defun tar-current-descriptor (&optional noerror)
 642   "Return the tar-descriptor of the current line, or signals an error."
 643   ;; I wish lines had plists, like in ZMACS...
 644   (or (nth (count-lines (point-min)
 645                         (save-excursion (beginning-of-line) (point)))
 646            tar-parse-info)
 647       (if noerror
 648           nil
 649           (error "This line does not describe a tar-file entry"))))
 650
 651 (defun tar-get-descriptor ()
 652   (let* ((descriptor (tar-current-descriptor))
 653          (tokens (tar-desc-tokens descriptor))
 654          (size (tar-header-size tokens))
 655          (link-p (tar-header-link-type tokens)))
 656     (if link-p
 657         (error "This is a %s, not a real file"
 658                (cond ((eq link-p 5) "directory")
 659                      ((eq link-p 20) "tar directory header")
 660                      ((eq link-p 29) "multivolume-continuation")
 661                      ((eq link-p 35) "sparse entry")
 662                      ((eq link-p 38) "volume header")
 663                      (t "link"))))
 664     (if (zerop size) (error "This is a zero-length file"))
 665     descriptor))
 666
 667 (defun tar-mouse-extract (event)
 668   "Extract a file whose tar directory line you click on."
 669   (interactive "e")
 670   (save-excursion
 671     (set-buffer (window-buffer (posn-window (event-end event))))
 672     (save-excursion
 673       (goto-char (posn-point (event-end event)))
 674       ;; Just make sure this doesn't get an error.
 675       (tar-get-descriptor)))
 676   (select-window (posn-window (event-end event)))
 677   (goto-char (posn-point (event-end event)))
 678   (tar-extract))
 679
 680 (defun tar-extract (&optional other-window-p)
 681   "In Tar mode, extract this entry of the tar file into its own buffer."
 682   (interactive)
 683   (let* ((view-p (eq other-window-p 'view))
 684          (descriptor (tar-get-descriptor))
 685          (tokens (tar-desc-tokens descriptor))
 686          (name (tar-header-name tokens))
 687          (size (tar-header-size tokens))
 688          (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
 689          (end (+ start size)))
 690     (let* ((tar-buffer (current-buffer))
 691            (tarname (file-name-nondirectory (buffer-file-name)))
 692            (bufname (concat (file-name-nondirectory name)
 693                             " ("
 694                             tarname
 695                             ")"))
 696            (read-only-p (or buffer-read-only view-p))
 697            (buffer (get-buffer bufname))
 698            (just-created nil))
 699       (if buffer
 700           nil
 701         (setq buffer (get-buffer-create bufname))
 702         (setq just-created t)
 703         (unwind-protect
 704             (progn
 705               (widen)
 706               (save-excursion
 707                 (set-buffer buffer)
 708                 (insert-buffer-substring tar-buffer start end)
 709                 (goto-char 0)
 710                 (setq buffer-file-name
 711                       (expand-file-name (concat tarname ":" name)))
 712                 (setq buffer-file-truename
 713                       (abbreviate-file-name buffer-file-name))
 714                 ;; Set the default-directory to the dir of the
 715                 ;; superior buffer.
 716                 (setq default-directory
 717                       (save-excursion
 718                         (set-buffer tar-buffer)
 719                         default-directory))
 720                 (normal-mode)  ; pick a mode.
 721                 (rename-buffer bufname)
 722                 (make-local-variable 'tar-superior-buffer)
 723                 (make-local-variable 'tar-superior-descriptor)
 724                 (setq tar-superior-buffer tar-buffer)
 725                 (setq tar-superior-descriptor descriptor)
 726                 (tar-subfile-mode 1)
 727                 (setq buffer-read-only read-only-p)
 728                 (set-buffer-modified-p nil))
 729               (set-buffer tar-buffer))
 730           (narrow-to-region 1 tar-header-offset)))
 731       (if view-p
 732           (progn
 733             (view-buffer buffer)
 734             (and just-created
 735                  (setq view-exit-action 'kill-buffer)))
 736         (if (eq other-window-p 'display)
 737             (display-buffer buffer)
 738           (if other-window-p
 739               (switch-to-buffer-other-window buffer)
 740             (switch-to-buffer buffer)))))))
 741
 742
 743 (defun tar-extract-other-window ()
 744   "*In Tar mode, find this entry of the tar file in another window."
 745   (interactive)
 746   (tar-extract t))
 747
 748 (defun tar-display-other-window ()
 749   "*In Tar mode, display this entry of the tar file in another window."
 750   (interactive)
 751   (tar-extract 'display))
 752
 753 (defun tar-view ()
 754   "*In Tar mode, view the tar file entry on this line."
 755   (interactive)
 756   (tar-extract 'view))
 757
 758
 759 (defun tar-read-file-name (&optional prompt)
 760   "Read a file name with this line's entry as the default."
 761   (or prompt (setq prompt "Copy to: "))
 762   (let* ((default-file (expand-file-name
 763                         (tar-header-name (tar-desc-tokens
 764                                           (tar-current-descriptor)))))
 765          (target (expand-file-name
 766                   (read-file-name prompt
 767                                   (file-name-directory default-file)
 768                                   default-file nil))))
 769     (if (or (string= "" (file-name-nondirectory target))
 770             (file-directory-p target))
 771         (setq target (concat (if (string-match "/$" target)
 772                                  (substring target 0 (1- (match-end 0)))
 773                                  target)
 774                              "/"
 775                              (file-name-nondirectory default-file))))
 776     target))
 777
 778
 779 (defun tar-copy (&optional to-file)
 780   "*In Tar mode, extract this entry of the tar file into a file on disk.
 781 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
 782 the current tar-entry."
 783   (interactive (list (tar-read-file-name)))
 784   (let* ((descriptor (tar-get-descriptor))
 785          (tokens (tar-desc-tokens descriptor))
 786          (name (tar-header-name tokens))
 787          (size (tar-header-size tokens))
 788          (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
 789          (end (+ start size)))
 790     (save-restriction
 791       (widen)
 792       (write-region start end to-file))
 793     (message "Copied tar entry %s to %s" name to-file)))
 794
 795 (defun tar-flag-deleted (p &optional unflag)
 796   "*In Tar mode, mark this sub-file to be deleted from the tar file.
 797 With a prefix argument, mark that many files."
 798   (interactive "p")
 799   (beginning-of-line)
 800   (tar-dotimes (i (if (< p 0) (- p) p))
 801     (if (tar-current-descriptor unflag) ; barf if we're not on an entry-line.
 802         (progn
 803           (delete-char 1)
 804           (insert (if unflag " " "D"))))
 805     (forward-line (if (< p 0) -1 1)))
 806   (if (eobp) nil (forward-char 36)))
 807
 808 (defun tar-unflag (p)
 809   "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
 810 With a prefix argument, un-mark that many files forward."
 811   (interactive "p")
 812   (tar-flag-deleted p t))
 813
 814 (defun tar-unflag-backwards (p)
 815   "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
 816 With a prefix argument, un-mark that many files backward."
 817   (interactive "p")
 818   (tar-flag-deleted (- p) t))
 819
 820
 821 (defun tar-expunge-internal ()
 822   "Expunge the tar-entry specified by the current line."
 823   (let* ((descriptor (tar-current-descriptor))
 824          (tokens (tar-desc-tokens descriptor))
 825          (line (tar-desc-data-start descriptor))
 826          (name (tar-header-name tokens))
 827          (size (tar-header-size tokens))
 828          (link-p (tar-header-link-type tokens))
 829          (start (tar-desc-data-start descriptor))
 830          (following-descs (cdr (memq descriptor tar-parse-info))))
 831     (if link-p (setq size 0)) ; size lies for hard-links.
 832     ;;
 833     ;; delete the current line...
 834     (beginning-of-line)
 835     (let ((line-start (point)))
 836       (end-of-line) (forward-char)
 837       (let ((line-len (- (point) line-start)))
 838         (delete-region line-start (point))
 839         ;;
 840         ;; decrement the header-pointer to be in synch...
 841         (setq tar-header-offset (- tar-header-offset line-len))))
 842     ;;
 843     ;; delete the data pointer...
 844     (setq tar-parse-info (delq descriptor tar-parse-info))
 845     ;;
 846     ;; delete the data from inside the file...
 847     (widen)
 848     (let* ((data-start (+ start tar-header-offset -513))
 849            (data-end (+ data-start 512 (ash (ash (+ size 511) -9) 9))))
 850       (delete-region data-start data-end)
 851       ;;
 852       ;; and finally, decrement the start-pointers of all following
 853       ;; entries in the archive.  This is a pig when deleting a bunch
 854       ;; of files at once - we could optimize this to only do the
 855       ;; iteration over the files that remain, or only iterate up to
 856       ;; the next file to be deleted.
 857       (let ((data-length (- data-end data-start)))
 858         (tar-dolist (desc following-descs)
 859           (tar-setf (tar-desc-data-start desc)
 860                     (- (tar-desc-data-start desc) data-length))))
 861       ))
 862   (narrow-to-region 1 tar-header-offset))
 863
 864
 865 (defun tar-expunge (&optional noconfirm)
 866   "*In Tar mode, delete all the archived files flagged for deletion.
 867 This does not modify the disk image; you must save the tar file itself
 868 for this to be permanent."
 869   (interactive)
 870   (if (or noconfirm
 871           (y-or-n-p "expunge files marked for deletion? "))
 872       (let ((n 0))
 873         (save-excursion
 874           (goto-char 0)
 875           (while (not (eobp))
 876             (if (looking-at "D")
 877                 (progn (tar-expunge-internal)
 878                        (setq n (1+ n)))
 879                 (forward-line 1)))
 880           ;; after doing the deletions, add any padding that may be necessary.
 881           (tar-pad-to-blocksize)
 882           (narrow-to-region 1 tar-header-offset)
 883           )
 884         (if (zerop n)
 885             (message "nothing to expunge.")
 886             (message "%s expunged.  Be sure to save this buffer." n)))))
 887
 888
 889 (defun tar-clear-modification-flags ()
 890   "Remove the stars at the beginning of each line."
 891   (interactive)
 892   (save-excursion
 893     (goto-char 1)
 894     (while (< (point) tar-header-offset)
 895       (if (not (eq (following-char) ?\ ))
 896           (progn (delete-char 1) (insert " ")))
 897       (forward-line 1))))
 898
 899
 900 (defun tar-chown-entry (new-uid)
 901   "*Change the user-id associated with this entry in the tar file.
 902 If this tar file was written by GNU tar, then you will be able to edit
 903 the user id as a string; otherwise, you must edit it as a number.
 904 You can force editing as a number by calling this with a prefix arg.
 905 This does not modify the disk image; you must save the tar file itself
 906 for this to be permanent."
 907   (interactive (list
 908                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
 909                    (if (or current-prefix-arg
 910                            (not (tar-header-magic tokens)))
 911                        (let (n)
 912                          (while (not (numberp (setq n (read-minibuffer
 913                                                         "New UID number: "
 914                                                         (format "%s" (tar-header-uid tokens)))))))
 915                          n)
 916                        (read-string "New UID string: " (tar-header-uname tokens))))))
 917   (cond ((stringp new-uid)
 918          (tar-setf (tar-header-uname (tar-desc-tokens (tar-current-descriptor)))
 919                    new-uid)
 920          (tar-alter-one-field tar-uname-offset (concat new-uid "\000")))
 921         (t
 922          (tar-setf (tar-header-uid (tar-desc-tokens (tar-current-descriptor)))
 923                    new-uid)
 924          (tar-alter-one-field tar-uid-offset
 925            (concat (substring (format "%6o" new-uid) 0 6) "\000 ")))))
 926
 927
 928 (defun tar-chgrp-entry (new-gid)
 929   "*Change the group-id associated with this entry in the tar file.
 930 If this tar file was written by GNU tar, then you will be able to edit
 931 the group id as a string; otherwise, you must edit it as a number.
 932 You can force editing as a number by calling this with a prefix arg.
 933 This does not modify the disk image; you must save the tar file itself
 934 for this to be permanent."
 935   (interactive (list
 936                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
 937                    (if (or current-prefix-arg
 938                            (not (tar-header-magic tokens)))
 939                        (let (n)
 940                          (while (not (numberp (setq n (read-minibuffer
 941                                                         "New GID number: "
 942                                                         (format "%s" (tar-header-gid tokens)))))))
 943                          n)
 944                        (read-string "New GID string: " (tar-header-gname tokens))))))
 945   (cond ((stringp new-gid)
 946          (tar-setf (tar-header-gname (tar-desc-tokens (tar-current-descriptor)))
 947                    new-gid)
 948          (tar-alter-one-field tar-gname-offset
 949            (concat new-gid "\000")))
 950         (t
 951          (tar-setf (tar-header-gid (tar-desc-tokens (tar-current-descriptor)))
 952                    new-gid)
 953          (tar-alter-one-field tar-gid-offset
 954            (concat (substring (format "%6o" new-gid) 0 6) "\000 ")))))
 955
 956 (defun tar-rename-entry (new-name)
 957   "*Change the name associated with this entry in the tar file.
 958 This does not modify the disk image; you must save the tar file itself
 959 for this to be permanent."
 960   (interactive
 961     (list (read-string "New name: "
 962             (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
 963   (if (string= "" new-name) (error "zero length name"))
 964   (if (> (length new-name) 98) (error "name too long"))
 965   (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
 966             new-name)
 967   (tar-alter-one-field 0
 968     (substring (concat new-name (make-string 99 0)) 0 99)))
 969
 970
 971 (defun tar-chmod-entry (new-mode)
 972   "*Change the protection bits associated with this entry in the tar file.
 973 This does not modify the disk image; you must save the tar file itself
 974 for this to be permanent."
 975   (interactive (list (tar-parse-octal-integer-safe
 976                        (read-string "New protection (octal): "))))
 977   (tar-setf (tar-header-mode (tar-desc-tokens (tar-current-descriptor)))
 978             new-mode)
 979   (tar-alter-one-field tar-mode-offset
 980     (concat (substring (format "%6o" new-mode) 0 6) "\000 ")))
 981
 982
 983 (defun tar-alter-one-field (data-position new-data-string)
 984   (let* ((descriptor (tar-current-descriptor))
 985          (tokens (tar-desc-tokens descriptor)))
 986     (unwind-protect
 987         (save-excursion
 988           ;;
 989           ;; update the header-line.
 990           (beginning-of-line)
 991           (let ((p (point)))
 992             (forward-line 1)
 993             (delete-region p (point))
 994             (insert (tar-header-block-summarize tokens) "\n")
 995             (setq tar-header-offset (point-max)))
 996
 997           (widen)
 998           (let* ((start (+ (tar-desc-data-start descriptor) tar-header-offset -513)))
 999             ;;
1000             ;; delete the old field and insert a new one.
1001             (goto-char (+ start data-position))
1002             (delete-region (point) (+ (point) (length new-data-string))) ; <--
1003             (insert new-data-string) ; <--
1004             ;;
1005             ;; compute a new checksum and insert it.
1006             (let ((chk (tar-header-block-checksum
1007                         (buffer-substring start (+ start 512)))))
1008               (goto-char (+ start tar-chk-offset))
1009               (delete-region (point) (+ (point) 8))
1010               (insert (format "%6o" chk))
1011               (insert 0)
1012               (insert ? )
1013               (tar-setf (tar-header-checksum tokens) chk)
1014               ;;
1015               ;; ok, make sure we didn't botch it.
1016               (tar-header-block-check-checksum
1017                 (buffer-substring start (+ start 512))
1018                 chk (tar-header-name tokens))
1019               )))
1020       (narrow-to-region 1 tar-header-offset))))
1021
1022
1023 (defun tar-octal-time (timeval)
1024   ;; Format a timestamp as 11 octal digits.  Ghod, I hope this works...
1025   (let ((hibits (car timeval)) (lobits (car (cdr timeval))))
1026     (insert (format "%05o%01o%05o"
1027                     (lsh hibits -2)
1028                     (logior (lsh (logand 3 hibits) 1) (> (logand lobits 32768) 0))
1029                     (logand 32767 lobits)
1030                     ))))
1031
1032 (defun tar-subfile-save-buffer ()
1033   "In tar subfile mode, save this buffer into its parent tar-file buffer.
1034 This doesn't write anything to disk; you must save the parent tar-file buffer
1035 to make your changes permanent."
1036   (interactive)
1037   (if (not (and (boundp 'tar-superior-buffer) tar-superior-buffer))
1038     (error "This buffer has no superior tar file buffer"))
1039   (if (not (and (boundp 'tar-superior-descriptor) tar-superior-descriptor))
1040     (error "This buffer doesn't have an index into its superior tar file!"))
1041   (save-excursion
1042   (let ((subfile (current-buffer))
1043         (subfile-size (buffer-size))
1044         (descriptor tar-superior-descriptor))
1045     (set-buffer tar-superior-buffer)
1046     (let* ((tokens (tar-desc-tokens descriptor))
1047            (start (tar-desc-data-start descriptor))
1048            (name (tar-header-name tokens))
1049            (size (tar-header-size tokens))
1050            (size-pad (ash (ash (+ size 511) -9) 9))
1051            (head (memq descriptor tar-parse-info))
1052            (following-descs (cdr head)))
1053       (if (not head)
1054         (error "Can't find this tar file entry in its parent tar file!"))
1055       (unwind-protect
1056        (save-excursion
1057         (widen)
1058         ;; delete the old data...
1059         (let* ((data-start (+ start tar-header-offset -1))
1060                (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
1061           (delete-region data-start data-end)
1062           ;; insert the new data...
1063           (goto-char data-start)
1064           (insert-buffer subfile)
1065           ;;
1066           ;; pad the new data out to a multiple of 512...
1067           (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
1068             (goto-char (+ data-start subfile-size))
1069             (insert (make-string (- subfile-size-pad subfile-size) 0))
1070             ;;
1071             ;; update the data pointer of this and all following files...
1072             (tar-setf (tar-header-size tokens) subfile-size)
1073             (let ((difference (- subfile-size-pad size-pad)))
1074               (tar-dolist (desc following-descs)
1075                 (tar-setf (tar-desc-data-start desc)
1076                           (+ (tar-desc-data-start desc) difference))))
1077             ;;
1078             ;; Update the size field in the header block.
1079             (let ((header-start (- data-start 512)))
1080               (goto-char (+ header-start tar-size-offset))
1081               (delete-region (point) (+ (point) 12))
1082               (insert (format "%11o" subfile-size))
1083               (insert ? )
1084               ;;
1085               ;; Maybe update the datestamp.
1086               (if (not tar-update-datestamp)
1087                   nil
1088                 (goto-char (+ header-start tar-time-offset))
1089                 (delete-region (point) (+ (point) 12))
1090                 (insert (tar-octal-time (current-time)))
1091                 (insert ? ))
1092               ;;
1093               ;; compute a new checksum and insert it.
1094               (let ((chk (tar-header-block-checksum
1095                           (buffer-substring header-start data-start))))
1096                 (goto-char (+ header-start tar-chk-offset))
1097                 (delete-region (point) (+ (point) 8))
1098                 (insert (format "%6o" chk))
1099                 (insert 0)
1100                 (insert ? )
1101                 (tar-setf (tar-header-checksum tokens) chk)))
1102             ;;
1103             ;; alter the descriptor-line...
1104             ;;
1105             (let ((position (- (length tar-parse-info) (length head))))
1106               (goto-char 1)
1107               (next-line position)
1108               (beginning-of-line)
1109               (let ((p (point))
1110                     after
1111                     (m (set-marker (make-marker) tar-header-offset)))
1112                 (forward-line 1)
1113                 (setq after (point))
1114                 ;; Insert the new text after the old, before deleting,
1115                 ;; to preserve the window start.
1116                 (insert-before-markers (tar-header-block-summarize tokens t) "\n")
1117                 (delete-region p after)
1118                 (setq tar-header-offset (marker-position m)))
1119               )))
1120         ;; after doing the insertion, add any final padding that may be necessary.
1121         (tar-pad-to-blocksize))
1122        (narrow-to-region 1 tar-header-offset)))
1123     (set-buffer-modified-p t)   ; mark the tar file as modified
1124     (set-buffer subfile)
1125     (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
1126     (message "saved into tar-buffer `%s' -- remember to save that buffer!"
1127              (buffer-name tar-superior-buffer))
1128     ;; Prevent ordinary saving from happening.
1129     t)))
1130
1131
1132 (defun tar-pad-to-blocksize ()
1133   "If we are being anal about tar file blocksizes, fix up the current buffer.
1134 Leaves the region wide."
1135   (if (null tar-anal-blocksize)
1136       nil
1137     (widen)
1138     (let* ((last-desc (nth (1- (length tar-parse-info)) tar-parse-info))
1139            (start (tar-desc-data-start last-desc))
1140            (tokens (tar-desc-tokens last-desc))
1141            (link-p (tar-header-link-type tokens))
1142            (size (if link-p 0 (tar-header-size tokens)))
1143            (data-end (+ start size))
1144            (bbytes (ash tar-anal-blocksize 9))
1145            (pad-to (+ bbytes (* bbytes (/ (1- data-end) bbytes))))
1146            (inhibit-read-only t) ; ##
1147            )
1148       ;; If the padding after the last data is too long, delete some;
1149       ;; else insert some until we are padded out to the right number of blocks.
1150       ;;
1151       (goto-char (+ (or tar-header-offset 0) data-end))
1152       (if (> (1+ (buffer-size)) (+ (or tar-header-offset 0) pad-to))
1153           (delete-region (+ (or tar-header-offset 0) pad-to) (1+ (buffer-size)))
1154           (insert (make-string (- (+ (or tar-header-offset 0) pad-to)
1155                                   (1+ (buffer-size)))
1156                                0)))
1157       )))
1158
1159
1160 ;; Used in write-file-hook to write tar-files out correctly.
1161 (defun tar-mode-maybe-write-tar-file ()
1162   ;;
1163   ;; If the current buffer is in Tar mode and has its header-offset set,
1164   ;; only write out the part of the file after the header-offset.
1165   ;;
1166   (if (and (eq major-mode 'tar-mode)
1167            (and (boundp 'tar-header-offset) tar-header-offset))
1168       (unwind-protect
1169         (save-excursion
1170           (tar-clear-modification-flags)
1171           (widen)
1172           ;; Doing this here confuses things - the region gets left too wide!
1173           ;; I suppose this is run in a context where changing the buffer is bad.
1174           ;; (tar-pad-to-blocksize)
1175           (write-region tar-header-offset (1+ (buffer-size)) buffer-file-name nil t)
1176           ;; return T because we've written the file.
1177           t)
1178         (narrow-to-region 1 tar-header-offset)
1179         t)
1180       ;; return NIL because we haven't.
1181       nil))
1182
1183 \f
1184 ;;; Patch it in.
1185
1186 (or (memq 'tar-mode-maybe-write-tar-file write-file-hooks)
1187     (setq write-file-hooks
1188           (cons 'tar-mode-maybe-write-tar-file write-file-hooks)))
1189
1190 (provide 'tar-mode)
1191
1192 ;;; tar-mode.el ends here