lisp/tar-mode.el

   1 ;;; tar-mode.el --- simple editing of tar files from GNU emacs
   2
   3 ;; Copyright (C) 1990, 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
   4
   5 ;; Author: Jamie Zawinski <jwz@lucid.com>
   6 ;; Maintainer: FSF
   7 ;; Created: 04 Apr 1990
   8 ;; Keywords: unix
   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 ;; This package attempts to make dealing with Unix 'tar' archives easier.
  30 ;; When this code is loaded, visiting a file whose name ends in '.tar' will
  31 ;; cause the contents of that archive file to be displayed in a Dired-like
  32 ;; listing.  It is then possible to use the customary Dired keybindings to
  33 ;; extract sub-files from that archive, either by reading them into their own
  34 ;; editor buffers, or by copying them directly to arbitrary files on disk.
  35 ;; It is also possible to delete sub-files from within the tar file and write
  36 ;; the modified archive back to disk, or to edit sub-files within the archive
  37 ;; and re-insert the modified files into the archive.  See the documentation
  38 ;; string of tar-mode for more info.
  39
  40 ;; This code now understands the extra fields that GNU tar adds to tar files.
  41
  42 ;; This interacts correctly with "uncompress.el" in the Emacs library,
  43 ;; which you get with
  44 ;;
  45 ;;  (autoload 'uncompress-while-visiting "uncompress")
  46 ;;  (setq auto-mode-alist (cons '("\\.Z$" . uncompress-while-visiting)
  47 ;;                         auto-mode-alist))
  48 ;;
  49 ;; Do not attempt to use tar-mode.el with crypt.el, you will lose.
  50
  51 ;;    ***************   TO DO   ***************
  52 ;;
  53 ;; o  chmod should understand "a+x,og-w".
  54 ;;
  55 ;; o  It's not possible to add a NEW file to a tar archive; not that
  56 ;;    important, but still...
  57 ;;
  58 ;; o  The code is less efficient that it could be - in a lot of places, I
  59 ;;    pull a 512-character string out of the buffer and parse it, when I could
  60 ;;    be parsing it in place, not garbaging a string.  Should redo that.
  61 ;;
  62 ;; o  I'd like a command that searches for a string/regexp in every subfile
  63 ;;    of an archive, where <esc> would leave you in a subfile-edit buffer.
  64 ;;    (Like the Meta-R command of the Zmacs mail reader.)
  65 ;;
  66 ;; o  Sometimes (but not always) reverting the tar-file buffer does not
  67 ;;    re-grind the listing, and you are staring at the binary tar data.
  68 ;;    Typing 'g' again immediately after that will always revert and re-grind
  69 ;;    it, though.  I have no idea why this happens.
  70 ;;
  71 ;; o  Tar-mode interacts poorly with crypt.el and zcat.el because the tar
  72 ;;    write-file-hook actually writes the file.  Instead it should remove the
  73 ;;    header (and conspire to put it back afterwards) so that other write-file
  74 ;;    hooks which frob the buffer have a chance to do their dirty work.  There
  75 ;;    might be a problem if the tar write-file-hook does not come *first* on
  76 ;;    the list.
  77 ;;
  78 ;; o  Block files, sparse files, continuation files, and the various header
  79 ;;    types aren't editable.  Actually I don't know that they work at all.
  80
  81 ;; Rationale:
  82
  83 ;; Why does tar-mode edit the file itself instead of using tar?
  84
  85 ;; That means that you can edit tar files which you don't have room for
  86 ;; on your local disk.
  87
  88 ;; I don't know about recent features in gnu tar, but old versions of tar
  89 ;; can't replace a file in the middle of a tar file with a new version.
  90 ;; Tar-mode can.  I don't think tar can do things like chmod the subfiles.
  91 ;; An implementation which involved unpacking and repacking the file into
  92 ;; some scratch directory would be very wasteful, and wouldn't be able to
  93 ;; preserve the file owners.
  94
  95 ;;; Code:
  96
  97 (defgroup tar nil
  98   "Simple editing of tar files."
  99   :prefix "tar-"
 100   :group 'data)
 101
 102 (defcustom tar-anal-blocksize 20
 103   "*The blocksize of tar files written by Emacs, or nil, meaning don't care.
 104 The blocksize of a tar file is not really the size of the blocks; rather, it is
 105 the number of blocks written with one system call.  When tarring to a tape,
 106 this is the size of the *tape* blocks, but when writing to a file, it doesn't
 107 matter much.  The only noticeable difference is that if a tar file does not
 108 have a blocksize of 20, tar will tell you that; all this really controls is
 109 how many null padding bytes go on the end of the tar file."
 110   :type '(choice integer (const nil))
 111   :group 'tar)
 112
 113 (defcustom tar-update-datestamp nil
 114   "*Non-nil means tar-mode should play fast and loose with sub-file datestamps.
 115 If this is true, then editing and saving a tar file entry back into its
 116 tar file will update its datestamp.  If false, the datestamp is unchanged.
 117 You may or may not want this - it is good in that you can tell when a file
 118 in a tar archive has been changed, but it is bad for the same reason that
 119 editing a file in the tar archive at all is bad - the changed version of
 120 the file never exists on disk."
 121   :type 'boolean
 122   :group 'tar)
 123
 124 (defcustom tar-mode-show-date nil
 125   "*Non-nil means Tar mode should show the date/time of each subfile.
 126 This information is useful, but it takes screen space away from file names."
 127   :type 'boolean
 128   :group 'tar)
 129
 130 (defvar tar-parse-info nil)
 131 (defvar tar-header-offset nil)
 132 (defvar tar-superior-buffer nil)
 133 (defvar tar-superior-descriptor nil)
 134 (defvar tar-subfile-mode nil)
 135
 136 (put 'tar-parse-info 'permanent-local t)
 137 (put 'tar-header-offset 'permanent-local t)
 138 (put 'tar-superior-buffer 'permanent-local t)
 139 (put 'tar-superior-descriptor 'permanent-local t)
 140 \f
 141 ;;; First, duplicate some Common Lisp functions; I used to just (require 'cl)
 142 ;;; but "cl.el" was messing some people up (also it's really big).
 143
 144 (defmacro tar-setf (form val)
 145   "A mind-numbingly simple implementation of setf."
 146   (let ((mform (macroexpand form (and (boundp 'byte-compile-macro-environment)
 147                                       byte-compile-macro-environment))))
 148     (cond ((symbolp mform) (list 'setq mform val))
 149           ((not (consp mform)) (error "can't setf %s" form))
 150           ((eq (car mform) 'aref)
 151            (list 'aset (nth 1 mform) (nth 2 mform) val))
 152           ((eq (car mform) 'car)
 153            (list 'setcar (nth 1 mform) val))
 154           ((eq (car mform) 'cdr)
 155            (list 'setcdr (nth 1 mform) val))
 156           (t (error "don't know how to setf %s" form)))))
 157
 158 (defmacro tar-dolist (control &rest body)
 159   "syntax: (dolist (var-name list-expr &optional return-value) &body body)"
 160   (let ((var (car control))
 161         (init (car (cdr control)))
 162         (val (car (cdr (cdr control)))))
 163     (list 'let (list (list '_dolist_iterator_ init))
 164           (list 'while '_dolist_iterator_
 165             (cons 'let
 166               (cons (list (list var '(car _dolist_iterator_)))
 167                     (append body
 168                             (list (list 'setq '_dolist_iterator_
 169                                         (list 'cdr '_dolist_iterator_)))))))
 170           val)))
 171
 172 (defmacro tar-dotimes (control &rest body)
 173   "syntax: (dolist (var-name count-expr &optional return-value) &body body)"
 174   (let ((var (car control))
 175         (n (car (cdr control)))
 176         (val (car (cdr (cdr control)))))
 177     (list 'let (list (list '_dotimes_end_ n)
 178                      (list var 0))
 179           (cons 'while
 180                 (cons (list '< var '_dotimes_end_)
 181                       (append body
 182                               (list (list 'setq var (list '1+ var))))))
 183           val)))
 184
 185 \f
 186 ;;; down to business.
 187
 188 (defmacro make-tar-header (name mode uid git size date ck lt ln
 189                            magic uname gname devmaj devmin)
 190   (list 'vector name mode uid git size date ck lt ln
 191         magic uname gname devmaj devmin))
 192
 193 (defmacro tar-header-name (x) (list 'aref x 0))
 194 (defmacro tar-header-mode (x) (list 'aref x 1))
 195 (defmacro tar-header-uid  (x) (list 'aref x 2))
 196 (defmacro tar-header-gid  (x) (list 'aref x 3))
 197 (defmacro tar-header-size (x) (list 'aref x 4))
 198 (defmacro tar-header-date (x) (list 'aref x 5))
 199 (defmacro tar-header-checksum  (x) (list 'aref x 6))
 200 (defmacro tar-header-link-type (x) (list 'aref x 7))
 201 (defmacro tar-header-link-name (x) (list 'aref x 8))
 202 (defmacro tar-header-magic (x) (list 'aref x 9))
 203 (defmacro tar-header-uname (x) (list 'aref x 10))
 204 (defmacro tar-header-gname (x) (list 'aref x 11))
 205 (defmacro tar-header-dmaj (x) (list 'aref x 12))
 206 (defmacro tar-header-dmin (x) (list 'aref x 13))
 207
 208 (defmacro make-tar-desc (data-start tokens)
 209   (list 'cons data-start tokens))
 210
 211 (defmacro tar-desc-data-start (x) (list 'car x))
 212 (defmacro tar-desc-tokens     (x) (list 'cdr x))
 213
 214 (defconst tar-name-offset 0)
 215 (defconst tar-mode-offset (+ tar-name-offset 100))
 216 (defconst tar-uid-offset  (+ tar-mode-offset 8))
 217 (defconst tar-gid-offset  (+ tar-uid-offset 8))
 218 (defconst tar-size-offset (+ tar-gid-offset 8))
 219 (defconst tar-time-offset (+ tar-size-offset 12))
 220 (defconst tar-chk-offset  (+ tar-time-offset 12))
 221 (defconst tar-linkp-offset (+ tar-chk-offset 8))
 222 (defconst tar-link-offset (+ tar-linkp-offset 1))
 223 ;;; GNU-tar specific slots.
 224 (defconst tar-magic-offset (+ tar-link-offset 100))
 225 (defconst tar-uname-offset (+ tar-magic-offset 8))
 226 (defconst tar-gname-offset (+ tar-uname-offset 32))
 227 (defconst tar-dmaj-offset (+ tar-gname-offset 32))
 228 (defconst tar-dmin-offset (+ tar-dmaj-offset 8))
 229 (defconst tar-end-offset (+ tar-dmin-offset 8))
 230
 231 (defun tar-header-block-tokenize (string)
 232   "Return a `tar-header' structure.
 233 This is a list of name, mode, uid, gid, size,
 234 write-date, checksum, link-type, and link-name."
 235   (cond ((< (length string) 512) nil)
 236         (;(some 'plusp string)           ; <-- oops, massive cycle hog!
 237          (or (not (= 0 (aref string 0))) ; This will do.
 238              (not (= 0 (aref string 101))))
 239          (let* ((name-end (1- tar-mode-offset))
 240                 (link-end (1- tar-magic-offset))
 241                 (uname-end (1- tar-gname-offset))
 242                 (gname-end (1- tar-dmaj-offset))
 243                 (link-p (aref string tar-linkp-offset))
 244                 (magic-str (substring string tar-magic-offset (1- tar-uname-offset)))
 245                 (uname-valid-p (or (string= "ustar  " magic-str) (string= "GNUtar " magic-str)))
 246                 name
 247                 (nulsexp   "[^\000]*\000"))
 248            (and (string-match nulsexp string tar-name-offset) (setq name-end (min name-end (1- (match-end 0)))))
 249            (and (string-match nulsexp string tar-link-offset) (setq link-end (min link-end (1- (match-end 0)))))
 250            (and (string-match nulsexp string tar-uname-offset) (setq uname-end (min uname-end (1- (match-end 0)))))
 251            (and (string-match nulsexp string tar-gname-offset) (setq gname-end (min gname-end (1- (match-end 0)))))
 252            (setq name (substring string tar-name-offset name-end)
 253                  link-p (if (or (= link-p 0) (= link-p ?0))
 254                             nil
 255                           (- link-p ?0)))
 256            (if (and (null link-p) (string-match "/$" name)) (setq link-p 5)) ; directory
 257            (make-tar-header
 258              name
 259              (tar-parse-octal-integer string tar-mode-offset (1- tar-uid-offset))
 260              (tar-parse-octal-integer string tar-uid-offset (1- tar-gid-offset))
 261              (tar-parse-octal-integer string tar-gid-offset (1- tar-size-offset))
 262              (tar-parse-octal-integer string tar-size-offset (1- tar-time-offset))
 263              (tar-parse-octal-long-integer string tar-time-offset (1- tar-chk-offset))
 264              (tar-parse-octal-integer string tar-chk-offset (1- tar-linkp-offset))
 265              link-p
 266              (substring string tar-link-offset link-end)
 267              uname-valid-p
 268              (and uname-valid-p (substring string tar-uname-offset uname-end))
 269              (and uname-valid-p (substring string tar-gname-offset gname-end))
 270              (tar-parse-octal-integer string tar-dmaj-offset (1- tar-dmin-offset))
 271              (tar-parse-octal-integer string tar-dmin-offset (1- tar-end-offset))
 272              )))
 273         (t 'empty-tar-block)))
 274
 275
 276 (defun tar-parse-octal-integer (string &optional start end)
 277   (if (null start) (setq start 0))
 278   (if (null end) (setq end (length string)))
 279   (if (= (aref string start) 0)
 280       0
 281     (let ((n 0))
 282       (while (< start end)
 283         (setq n (if (< (aref string start) ?0) n
 284                   (+ (* n 8) (- (aref string start) ?0)))
 285               start (1+ start)))
 286       n)))
 287
 288 (defun tar-parse-octal-long-integer (string &optional start end)
 289   (if (null start) (setq start 0))
 290   (if (null end) (setq end (length string)))
 291   (if (= (aref string start) 0)
 292       (list 0 0)
 293     (let ((lo 0)
 294           (hi 0))
 295       (while (< start end)
 296         (if (>= (aref string start) ?0)
 297             (setq lo (+ (* lo 8) (- (aref string start) ?0))
 298                   hi (+ (* hi 8) (ash lo -16))
 299                   lo (logand lo 65535)))
 300         (setq start (1+ start)))
 301       (list hi lo))))
 302
 303 (defun tar-parse-octal-integer-safe (string)
 304   (let ((L (length string)))
 305     (if (= L 0) (error "empty string"))
 306     (tar-dotimes (i L)
 307        (if (or (< (aref string i) ?0)
 308                (> (aref string i) ?7))
 309            (error "'%c' is not an octal digit"))))
 310   (tar-parse-octal-integer string))
 311
 312
 313 (defun tar-header-block-checksum (string)
 314   "Compute and return a tar-acceptable checksum for this block."
 315   (let* ((chk-field-start tar-chk-offset)
 316          (chk-field-end (+ chk-field-start 8))
 317          (sum 0)
 318          (i 0))
 319     ;; Add up all of the characters except the ones in the checksum field.
 320     ;; Add that field as if it were filled with spaces.
 321     (while (< i chk-field-start)
 322       (setq sum (+ sum (aref string i))
 323             i (1+ i)))
 324     (setq i chk-field-end)
 325     (while (< i 512)
 326       (setq sum (+ sum (aref string i))
 327             i (1+ i)))
 328     (+ sum (* 32 8))))
 329
 330 (defun tar-header-block-check-checksum (hblock desired-checksum file-name)
 331   "Beep and print a warning if the checksum doesn't match."
 332   (if (not (= desired-checksum (tar-header-block-checksum hblock)))
 333       (progn (beep) (message "Invalid checksum for file %s!" file-name))))
 334
 335 (defun tar-header-block-recompute-checksum (hblock)
 336   "Modifies the given string to have a valid checksum field."
 337   (let* ((chk (tar-header-block-checksum hblock))
 338          (chk-string (format "%6o" chk))
 339          (l (length chk-string)))
 340     (aset hblock 154 0)
 341     (aset hblock 155 32)
 342     (tar-dotimes (i l) (aset hblock (- 153 i) (aref chk-string (- l i 1)))))
 343   hblock)
 344
 345 (defun tar-clip-time-string (time)
 346   (let ((str (current-time-string time)))
 347     (concat (substring str 4 16) (substring str 19 24))))
 348
 349 (defun tar-grind-file-mode (mode string start)
 350   "Store `-rw--r--r--' indicating MODE into STRING beginning at START.
 351 MODE should be an integer which is a file mode value."
 352   (aset string start       (if (zerop (logand 256 mode)) ?- ?r))
 353   (aset string (+ start 1) (if (zerop (logand 128 mode)) ?- ?w))
 354   (aset string (+ start 2) (if (zerop (logand  64 mode)) ?- ?x))
 355   (aset string (+ start 3) (if (zerop (logand  32 mode)) ?- ?r))
 356   (aset string (+ start 4) (if (zerop (logand  16 mode)) ?- ?w))
 357   (aset string (+ start 5) (if (zerop (logand   8 mode)) ?- ?x))
 358   (aset string (+ start 6) (if (zerop (logand   4 mode)) ?- ?r))
 359   (aset string (+ start 7) (if (zerop (logand   2 mode)) ?- ?w))
 360   (aset string (+ start 8) (if (zerop (logand   1 mode)) ?- ?x))
 361   (if (zerop (logand 1024 mode)) nil (aset string (+ start 2) ?s))
 362   (if (zerop (logand 2048 mode)) nil (aset string (+ start 5) ?s))
 363   string)
 364
 365 (defun tar-header-block-summarize (tar-hblock &optional mod-p)
 366   "Returns a line similar to the output of `tar -vtf'."
 367   (let ((name (tar-header-name tar-hblock))
 368         (mode (tar-header-mode tar-hblock))
 369         (uid (tar-header-uid tar-hblock))
 370         (gid (tar-header-gid tar-hblock))
 371         (uname (tar-header-uname tar-hblock))
 372         (gname (tar-header-gname tar-hblock))
 373         (size (tar-header-size tar-hblock))
 374         (time (tar-header-date tar-hblock))
 375         (ck (tar-header-checksum tar-hblock))
 376         (link-p (tar-header-link-type tar-hblock))
 377         (link-name (tar-header-link-name tar-hblock))
 378         )
 379     (let* ((left 11)
 380            (namew 8)
 381            (groupw 8)
 382            (sizew 8)
 383            (datew (if tar-mode-show-date 18 0))
 384            (slash (1- (+ left namew)))
 385            (lastdigit (+ slash groupw sizew))
 386            (datestart (+ lastdigit 2))
 387            (namestart (+ datestart datew))
 388            (string (make-string (+ namestart (length name) (if link-p (+ 5 (length link-name)) 0)) 32))
 389            (type (tar-header-link-type tar-hblock)))
 390       (aset string 0 (if mod-p ?* ? ))
 391       (aset string 1
 392             (cond ((or (eq type nil) (eq type 0)) ?-)
 393                   ((eq type 1) ?l)  ; link
 394                   ((eq type 2) ?s)  ; symlink
 395                   ((eq type 3) ?c)  ; char special
 396                   ((eq type 4) ?b)  ; block special
 397                   ((eq type 5) ?d)  ; directory
 398                   ((eq type 6) ?p)  ; FIFO/pipe
 399                   ((eq type 20) ?*) ; directory listing
 400                   ((eq type 29) ?M) ; multivolume continuation
 401                   ((eq type 35) ?S) ; sparse
 402                   ((eq type 38) ?V) ; volume header
 403                   ))
 404       (tar-grind-file-mode mode string 2)
 405       (setq uid (if (= 0 (length uname)) (int-to-string uid) uname))
 406       (setq gid (if (= 0 (length gname)) (int-to-string gid) gname))
 407       (setq size (int-to-string size))
 408       (setq time (tar-clip-time-string time))
 409       (tar-dotimes (i (min (1- namew) (length uid))) (aset string (- slash i) (aref uid (- (length uid) i 1))))
 410       (aset string (1+ slash) ?/)
 411       (tar-dotimes (i (min (1- groupw) (length gid))) (aset string (+ (+ slash 2) i) (aref gid i)))
 412       (tar-dotimes (i (min sizew (length size))) (aset string (- lastdigit i) (aref size (- (length size) i 1))))
 413       (if tar-mode-show-date
 414           (tar-dotimes (i (length time)) (aset string (+ datestart i) (aref time i))))
 415       (tar-dotimes (i (length name)) (aset string (+ namestart i) (aref name i)))
 416       (if (or (eq link-p 1) (eq link-p 2))
 417           (progn
 418             (tar-dotimes (i 3) (aset string (+ namestart 1 (length name) i) (aref (if (= link-p 1) "==>" "-->") i)))
 419             (tar-dotimes (i (length link-name)) (aset string (+ namestart 5 (length name) i) (aref link-name i)))))
 420       (put-text-property namestart (length string)
 421                          'mouse-face 'highlight string)
 422       string)))
 423
 424
 425 (defun tar-summarize-buffer ()
 426   "Parse the contents of the tar file in the current buffer.
 427 Place a dired-like listing on the front;
 428 then narrow to it, so that only that listing
 429 is visible (and the real data of the buffer is hidden)."
 430   (message "Parsing tar file...")
 431   (let* ((result '())
 432          (pos 1)
 433          (bs (max 1 (- (buffer-size) 1024))) ; always 2+ empty blocks at end.
 434          (bs100 (max 1 (/ bs 100)))
 435          tokens)
 436     (while (and (<= (+ pos 512) (point-max))
 437                 (not (eq 'empty-tar-block
 438                          (setq tokens
 439                                (tar-header-block-tokenize
 440                                 (buffer-substring pos (+ pos 512)))))))
 441       (setq pos (+ pos 512))
 442       (message "Parsing tar file...%d%%"
 443                ;(/ (* pos 100) bs)   ; this gets round-off lossage
 444                (/ pos bs100)         ; this doesn't
 445                )
 446       (if (eq (tar-header-link-type tokens) 20)
 447           ;; Foo.  There's an extra empty block after these.
 448           (setq pos (+ pos 512)))
 449       (let ((size (tar-header-size tokens)))
 450         (if (< size 0)
 451             (error "%s has size %s - corrupted"
 452                    (tar-header-name tokens) size))
 453         ;
 454         ; This is just too slow.  Don't really need it anyway....
 455         ;(tar-header-block-check-checksum
 456         ;  hblock (tar-header-block-checksum hblock)
 457         ;  (tar-header-name tokens))
 458
 459         (setq result (cons (make-tar-desc pos tokens) result))
 460
 461         (and (null (tar-header-link-type tokens))
 462              (> size 0)
 463              (setq pos
 464                    (+ pos 512 (ash (ash (1- size) -9) 9))        ; this works
 465                    ;(+ pos (+ size (- 512 (rem (1- size) 512)))) ; this doesn't
 466                    ))))
 467     (make-local-variable 'tar-parse-info)
 468     (setq tar-parse-info (nreverse result))
 469     ;; A tar file should end with a block or two of nulls,
 470     ;; but let's not get a fatal error if it doesn't.
 471     (if (eq tokens 'empty-tar-block)
 472         (message "Parsing tar file...done")
 473       (message "Warning: premature EOF parsing tar file")))
 474   (save-excursion
 475     (goto-char (point-min))
 476     (let ((buffer-read-only nil)
 477           (summaries nil))
 478       ;; Collect summary lines and insert them all at once since tar files
 479       ;; can be pretty big.
 480       (tar-dolist (tar-desc (reverse tar-parse-info))
 481         (setq summaries
 482               (cons (tar-header-block-summarize (tar-desc-tokens tar-desc))
 483                     (cons "\n"
 484                           summaries))))
 485       (insert (apply 'concat summaries))
 486       (make-local-variable 'tar-header-offset)
 487       (setq tar-header-offset (point))
 488       (narrow-to-region 1 tar-header-offset)
 489       (set-buffer-modified-p nil))))
 490 \f
 491 (defvar tar-mode-map nil "*Local keymap for Tar mode listings.")
 492
 493 (if tar-mode-map
 494     nil
 495   (setq tar-mode-map (make-keymap))
 496   (suppress-keymap tar-mode-map)
 497   (define-key tar-mode-map " " 'tar-next-line)
 498   (define-key tar-mode-map "C" 'tar-copy)
 499   (define-key tar-mode-map "d" 'tar-flag-deleted)
 500   (define-key tar-mode-map "\^D" 'tar-flag-deleted)
 501   (define-key tar-mode-map "e" 'tar-extract)
 502   (define-key tar-mode-map "f" 'tar-extract)
 503   (define-key tar-mode-map "\C-m" 'tar-extract)
 504   (define-key tar-mode-map [mouse-2] 'tar-mouse-extract)
 505   (define-key tar-mode-map "g" 'revert-buffer)
 506   (define-key tar-mode-map "h" 'describe-mode)
 507   (define-key tar-mode-map "n" 'tar-next-line)
 508   (define-key tar-mode-map "\^N" 'tar-next-line)
 509   (define-key tar-mode-map [down] 'tar-next-line)
 510   (define-key tar-mode-map "o" 'tar-extract-other-window)
 511   (define-key tar-mode-map "p" 'tar-previous-line)
 512   (define-key tar-mode-map "q" 'tar-quit)
 513   (define-key tar-mode-map "\^P" 'tar-previous-line)
 514   (define-key tar-mode-map [up] 'tar-previous-line)
 515   (define-key tar-mode-map "R" 'tar-rename-entry)
 516   (define-key tar-mode-map "u" 'tar-unflag)
 517   (define-key tar-mode-map "v" 'tar-view)
 518   (define-key tar-mode-map "x" 'tar-expunge)
 519   (define-key tar-mode-map "\177" 'tar-unflag-backwards)
 520   (define-key tar-mode-map "E" 'tar-extract-other-window)
 521   (define-key tar-mode-map "M" 'tar-chmod-entry)
 522   (define-key tar-mode-map "G" 'tar-chgrp-entry)
 523   (define-key tar-mode-map "O" 'tar-chown-entry)
 524   )
 525 \f
 526 ;; Make menu bar items.
 527
 528 ;; Get rid of the Edit menu bar item to save space.
 529 (define-key tar-mode-map [menu-bar edit] 'undefined)
 530
 531 (define-key tar-mode-map [menu-bar immediate]
 532   (cons "Immediate" (make-sparse-keymap "Immediate")))
 533
 534 (define-key tar-mode-map [menu-bar immediate view]
 535   '("View This File" . tar-view))
 536 (define-key tar-mode-map [menu-bar immediate display]
 537   '("Display in Other Window" . tar-display-other-window))
 538 (define-key tar-mode-map [menu-bar immediate find-file-other-window]
 539   '("Find in Other Window" . tar-extract-other-window))
 540 (define-key tar-mode-map [menu-bar immediate find-file]
 541   '("Find This File" . tar-extract))
 542
 543 (define-key tar-mode-map [menu-bar mark]
 544   (cons "Mark" (make-sparse-keymap "Mark")))
 545
 546 (define-key tar-mode-map [menu-bar mark unmark-all]
 547   '("Unmark All" . tar-clear-modification-flags))
 548 (define-key tar-mode-map [menu-bar mark deletion]
 549   '("Flag" . tar-flag-deleted))
 550 (define-key tar-mode-map [menu-bar mark unmark]
 551   '("Unflag" . tar-unflag))
 552
 553 (define-key tar-mode-map [menu-bar operate]
 554   (cons "Operate" (make-sparse-keymap "Operate")))
 555
 556 (define-key tar-mode-map [menu-bar operate chown]
 557   '("Change Owner..." . tar-chown-entry))
 558 (define-key tar-mode-map [menu-bar operate chgrp]
 559   '("Change Group..." . tar-chgrp-entry))
 560 (define-key tar-mode-map [menu-bar operate chmod]
 561   '("Change Mode..." . tar-chmod-entry))
 562 (define-key tar-mode-map [menu-bar operate rename]
 563   '("Rename to..." . tar-rename-entry))
 564 (define-key tar-mode-map [menu-bar operate copy]
 565   '("Copy to..." . tar-copy))
 566 (define-key tar-mode-map [menu-bar operate expunge]
 567   '("Expunge Marked Files" . tar-expunge))
 568 \f
 569 ;; tar mode is suitable only for specially formatted data.
 570 (put 'tar-mode 'mode-class 'special)
 571 (put 'tar-subfile-mode 'mode-class 'special)
 572
 573 ;;;###autoload
 574 (defun tar-mode ()
 575   "Major mode for viewing a tar file as a dired-like listing of its contents.
 576 You can move around using the usual cursor motion commands.
 577 Letters no longer insert themselves.
 578 Type `e' to pull a file out of the tar file and into its own buffer;
 579 or click mouse-2 on the file's line in the Tar mode buffer.
 580 Type `c' to copy an entry from the tar file into another file on disk.
 581
 582 If you edit a sub-file of this archive (as with the `e' command) and
 583 save it with Control-x Control-s, the contents of that buffer will be
 584 saved back into the tar-file buffer; in this way you can edit a file
 585 inside of a tar archive without extracting it and re-archiving it.
 586
 587 See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
 588 \\{tar-mode-map}"
 589   ;; this is not interactive because you shouldn't be turning this
 590   ;; mode on and off.  You can corrupt things that way.
 591   ;; rms: with permanent locals, it should now be possible to make this work
 592   ;; interactively in some reasonable fashion.
 593   (kill-all-local-variables)
 594   (make-local-variable 'tar-header-offset)
 595   (make-local-variable 'tar-parse-info)
 596   (make-local-variable 'require-final-newline)
 597   (setq require-final-newline nil) ; binary data, dude...
 598   (make-local-variable 'revert-buffer-function)
 599   (setq revert-buffer-function 'tar-mode-revert)
 600   (make-local-variable 'enable-local-variables)
 601   (setq enable-local-variables nil)
 602   (make-local-variable 'next-line-add-newlines)
 603   (setq next-line-add-newlines nil)
 604   (setq major-mode 'tar-mode)
 605   (setq mode-name "Tar")
 606   (use-local-map tar-mode-map)
 607   (auto-save-mode 0)
 608   (make-local-variable 'write-contents-hooks)
 609   (setq write-contents-hooks '(tar-mode-write-file))
 610   (widen)
 611   (if (and (boundp 'tar-header-offset) tar-header-offset)
 612       (narrow-to-region 1 tar-header-offset)
 613       (tar-summarize-buffer))
 614   (run-hooks 'tar-mode-hook)
 615   )
 616
 617
 618 (defun tar-subfile-mode (p)
 619   "Minor mode for editing an element of a tar-file.
 620 This mode arranges for \"saving\" this buffer to write the data
 621 into the tar-file buffer that it came from.  The changes will actually
 622 appear on disk when you save the tar-file's buffer."
 623   (interactive "P")
 624   (or (and (boundp 'tar-superior-buffer) tar-superior-buffer)
 625       (error "This buffer is not an element of a tar file"))
 626 ;;; Don't do this, because it is redundant and wastes mode line space.
 627 ;;;  (or (assq 'tar-subfile-mode minor-mode-alist)
 628 ;;;      (setq minor-mode-alist (append minor-mode-alist
 629 ;;;                                  (list '(tar-subfile-mode " TarFile")))))
 630   (make-local-variable 'tar-subfile-mode)
 631   (setq tar-subfile-mode
 632         (if (null p)
 633             (not tar-subfile-mode)
 634             (> (prefix-numeric-value p) 0)))
 635   (cond (tar-subfile-mode
 636          (make-local-variable 'local-write-file-hooks)
 637          (setq local-write-file-hooks '(tar-subfile-save-buffer))
 638          ;; turn off auto-save.
 639          (auto-save-mode nil)
 640          (setq buffer-auto-save-file-name nil)
 641          (run-hooks 'tar-subfile-mode-hook))
 642         (t
 643          (kill-local-variable 'local-write-file-hooks))))
 644
 645
 646 ;; Revert the buffer and recompute the dired-like listing.
 647 (defun tar-mode-revert (&optional no-autosave no-confirm)
 648   (let ((revert-buffer-function nil)
 649         (old-offset tar-header-offset)
 650         success)
 651     (setq tar-header-offset nil)
 652     (unwind-protect
 653         (and (revert-buffer t no-confirm)
 654              (progn (widen)
 655                     (setq success t)
 656                     (tar-mode)))
 657       ;; If the revert was canceled,
 658       ;; put back the old value of tar-header-offset.
 659       (or success
 660           (setq tar-header-offset old-offset)))))
 661
 662
 663 (defun tar-next-line (p)
 664   (interactive "p")
 665   (forward-line p)
 666   (if (eobp) nil (forward-char (if tar-mode-show-date 54 36))))
 667
 668 (defun tar-previous-line (p)
 669   (interactive "p")
 670   (tar-next-line (- p)))
 671
 672 (defun tar-current-descriptor (&optional noerror)
 673   "Return the tar-descriptor of the current line, or signals an error."
 674   ;; I wish lines had plists, like in ZMACS...
 675   (or (nth (count-lines (point-min)
 676                         (save-excursion (beginning-of-line) (point)))
 677            tar-parse-info)
 678       (if noerror
 679           nil
 680           (error "This line does not describe a tar-file entry"))))
 681
 682 (defun tar-get-descriptor ()
 683   (let* ((descriptor (tar-current-descriptor))
 684          (tokens (tar-desc-tokens descriptor))
 685          (size (tar-header-size tokens))
 686          (link-p (tar-header-link-type tokens)))
 687     (if link-p
 688         (error "This is a %s, not a real file"
 689                (cond ((eq link-p 5) "directory")
 690                      ((eq link-p 20) "tar directory header")
 691                      ((eq link-p 29) "multivolume-continuation")
 692                      ((eq link-p 35) "sparse entry")
 693                      ((eq link-p 38) "volume header")
 694                      (t "link"))))
 695     (if (zerop size) (error "This is a zero-length file"))
 696     descriptor))
 697
 698 (defun tar-mouse-extract (event)
 699   "Extract a file whose tar directory line you click on."
 700   (interactive "e")
 701   (save-excursion
 702     (set-buffer (window-buffer (posn-window (event-end event))))
 703     (save-excursion
 704       (goto-char (posn-point (event-end event)))
 705       ;; Just make sure this doesn't get an error.
 706       (tar-get-descriptor)))
 707   (select-window (posn-window (event-end event)))
 708   (goto-char (posn-point (event-end event)))
 709   (tar-extract))
 710
 711 (defun tar-extract (&optional other-window-p)
 712   "In Tar mode, extract this entry of the tar file into its own buffer."
 713   (interactive)
 714   (let* ((view-p (eq other-window-p 'view))
 715          (descriptor (tar-get-descriptor))
 716          (tokens (tar-desc-tokens descriptor))
 717          (name (tar-header-name tokens))
 718          (size (tar-header-size tokens))
 719          (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
 720          (end (+ start size)))
 721     (let* ((tar-buffer (current-buffer))
 722            (tarname (file-name-nondirectory (buffer-file-name)))
 723            (bufname (concat (file-name-nondirectory name)
 724                             " ("
 725                             tarname
 726                             ")"))
 727            (read-only-p (or buffer-read-only view-p))
 728            (buffer (get-buffer bufname))
 729            (just-created nil))
 730       (if buffer
 731           nil
 732         (setq buffer (get-buffer-create bufname))
 733         (setq just-created t)
 734         (unwind-protect
 735             (progn
 736               (widen)
 737               (save-excursion
 738                 (set-buffer buffer)
 739                 (insert-buffer-substring tar-buffer start end)
 740                 (goto-char 0)
 741                 (setq buffer-file-name
 742                       (expand-file-name (concat tarname ":" name)))
 743                 (setq buffer-file-truename
 744                       (abbreviate-file-name buffer-file-name))
 745                 ;; Set the default-directory to the dir of the
 746                 ;; superior buffer.
 747                 (setq default-directory
 748                       (save-excursion
 749                         (set-buffer tar-buffer)
 750                         default-directory))
 751                 (normal-mode)  ; pick a mode.
 752                 (rename-buffer bufname)
 753                 (make-local-variable 'tar-superior-buffer)
 754                 (make-local-variable 'tar-superior-descriptor)
 755                 (setq tar-superior-buffer tar-buffer)
 756                 (setq tar-superior-descriptor descriptor)
 757                 (setq buffer-read-only read-only-p)
 758                 (set-buffer-modified-p nil)
 759                 (tar-subfile-mode 1))
 760               (set-buffer tar-buffer))
 761           (narrow-to-region 1 tar-header-offset)))
 762       (if view-p
 763           (view-buffer buffer (and just-created 'kill-buffer))
 764         (if (eq other-window-p 'display)
 765             (display-buffer buffer)
 766           (if other-window-p
 767               (switch-to-buffer-other-window buffer)
 768             (switch-to-buffer buffer)))))))
 769
 770
 771 (defun tar-extract-other-window ()
 772   "*In Tar mode, find this entry of the tar file in another window."
 773   (interactive)
 774   (tar-extract t))
 775
 776 (defun tar-display-other-window ()
 777   "*In Tar mode, display this entry of the tar file in another window."
 778   (interactive)
 779   (tar-extract 'display))
 780
 781 (defun tar-view ()
 782   "*In Tar mode, view the tar file entry on this line."
 783   (interactive)
 784   (tar-extract 'view))
 785
 786
 787 (defun tar-read-file-name (&optional prompt)
 788   "Read a file name with this line's entry as the default."
 789   (or prompt (setq prompt "Copy to: "))
 790   (let* ((default-file (expand-file-name
 791                         (tar-header-name (tar-desc-tokens
 792                                           (tar-current-descriptor)))))
 793          (target (expand-file-name
 794                   (read-file-name prompt
 795                                   (file-name-directory default-file)
 796                                   default-file nil))))
 797     (if (or (string= "" (file-name-nondirectory target))
 798             (file-directory-p target))
 799         (setq target (concat (if (string-match "/$" target)
 800                                  (substring target 0 (1- (match-end 0)))
 801                                  target)
 802                              "/"
 803                              (file-name-nondirectory default-file))))
 804     target))
 805
 806
 807 (defun tar-copy (&optional to-file)
 808   "*In Tar mode, extract this entry of the tar file into a file on disk.
 809 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
 810 the current tar-entry."
 811   (interactive (list (tar-read-file-name)))
 812   (let* ((descriptor (tar-get-descriptor))
 813          (tokens (tar-desc-tokens descriptor))
 814          (name (tar-header-name tokens))
 815          (size (tar-header-size tokens))
 816          (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
 817          (end (+ start size))
 818          (inhibit-file-name-handlers inhibit-file-name-handlers)
 819          (inhibit-file-name-operation inhibit-file-name-operation))
 820     (save-restriction
 821       (widen)
 822       ;; Inhibit compressing a subfile again if *both* name and
 823       ;; to-file are handled by jka-compr
 824       (if (and (eq (find-file-name-handler name 'write-region) 'jka-compr-handler)
 825                (eq (find-file-name-handler to-file 'write-region) 'jka-compr-handler))
 826           (setq inhibit-file-name-handlers
 827                 (cons 'jka-compr-handler
 828                       (and (eq inhibit-file-name-operation 'write-region)
 829                            inhibit-file-name-handlers))
 830                 inhibit-file-name-operation 'write-region))
 831       (write-region start end to-file))
 832     (message "Copied tar entry %s to %s" name to-file)))
 833
 834 (defun tar-flag-deleted (p &optional unflag)
 835   "*In Tar mode, mark this sub-file to be deleted from the tar file.
 836 With a prefix argument, mark that many files."
 837   (interactive "p")
 838   (beginning-of-line)
 839   (tar-dotimes (i (if (< p 0) (- p) p))
 840     (if (tar-current-descriptor unflag) ; barf if we're not on an entry-line.
 841         (progn
 842           (delete-char 1)
 843           (insert (if unflag " " "D"))))
 844     (forward-line (if (< p 0) -1 1)))
 845   (if (eobp) nil (forward-char 36)))
 846
 847 (defun tar-unflag (p)
 848   "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
 849 With a prefix argument, un-mark that many files forward."
 850   (interactive "p")
 851   (tar-flag-deleted p t))
 852
 853 (defun tar-unflag-backwards (p)
 854   "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
 855 With a prefix argument, un-mark that many files backward."
 856   (interactive "p")
 857   (tar-flag-deleted (- p) t))
 858
 859
 860 (defun tar-expunge-internal ()
 861   "Expunge the tar-entry specified by the current line."
 862   (let* ((descriptor (tar-current-descriptor))
 863          (tokens (tar-desc-tokens descriptor))
 864          (line (tar-desc-data-start descriptor))
 865          (name (tar-header-name tokens))
 866          (size (tar-header-size tokens))
 867          (link-p (tar-header-link-type tokens))
 868          (start (tar-desc-data-start descriptor))
 869          (following-descs (cdr (memq descriptor tar-parse-info))))
 870     (if link-p (setq size 0)) ; size lies for hard-links.
 871     ;;
 872     ;; delete the current line...
 873     (beginning-of-line)
 874     (let ((line-start (point)))
 875       (end-of-line) (forward-char)
 876       (let ((line-len (- (point) line-start)))
 877         (delete-region line-start (point))
 878         ;;
 879         ;; decrement the header-pointer to be in sync...
 880         (setq tar-header-offset (- tar-header-offset line-len))))
 881     ;;
 882     ;; delete the data pointer...
 883     (setq tar-parse-info (delq descriptor tar-parse-info))
 884     ;;
 885     ;; delete the data from inside the file...
 886     (widen)
 887     (let* ((data-start (+ start tar-header-offset -513))
 888            (data-end (+ data-start 512 (ash (ash (+ size 511) -9) 9))))
 889       (delete-region data-start data-end)
 890       ;;
 891       ;; and finally, decrement the start-pointers of all following
 892       ;; entries in the archive.  This is a pig when deleting a bunch
 893       ;; of files at once - we could optimize this to only do the
 894       ;; iteration over the files that remain, or only iterate up to
 895       ;; the next file to be deleted.
 896       (let ((data-length (- data-end data-start)))
 897         (tar-dolist (desc following-descs)
 898           (tar-setf (tar-desc-data-start desc)
 899                     (- (tar-desc-data-start desc) data-length))))
 900       ))
 901   (narrow-to-region 1 tar-header-offset))
 902
 903
 904 (defun tar-expunge (&optional noconfirm)
 905   "*In Tar mode, delete all the archived files flagged for deletion.
 906 This does not modify the disk image; you must save the tar file itself
 907 for this to be permanent."
 908   (interactive)
 909   (if (or noconfirm
 910           (y-or-n-p "Expunge files marked for deletion? "))
 911       (let ((n 0))
 912         (save-excursion
 913           (goto-char 0)
 914           (while (not (eobp))
 915             (if (looking-at "D")
 916                 (progn (tar-expunge-internal)
 917                        (setq n (1+ n)))
 918                 (forward-line 1)))
 919           ;; after doing the deletions, add any padding that may be necessary.
 920           (tar-pad-to-blocksize)
 921           (narrow-to-region 1 tar-header-offset)
 922           )
 923         (if (zerop n)
 924             (message "Nothing to expunge.")
 925             (message "%s files expunged.  Be sure to save this buffer." n)))))
 926
 927
 928 (defun tar-clear-modification-flags ()
 929   "Remove the stars at the beginning of each line."
 930   (interactive)
 931   (save-excursion
 932     (goto-char 1)
 933     (while (< (point) tar-header-offset)
 934       (if (not (eq (following-char) ?\ ))
 935           (progn (delete-char 1) (insert " ")))
 936       (forward-line 1))))
 937
 938
 939 (defun tar-chown-entry (new-uid)
 940   "*Change the user-id associated with this entry in the tar file.
 941 If this tar file was written by GNU tar, then you will be able to edit
 942 the user id as a string; otherwise, you must edit it as a number.
 943 You can force editing as a number by calling this with a prefix arg.
 944 This does not modify the disk image; you must save the tar file itself
 945 for this to be permanent."
 946   (interactive (list
 947                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
 948                    (if (or current-prefix-arg
 949                            (not (tar-header-magic tokens)))
 950                        (let (n)
 951                          (while (not (numberp (setq n (read-minibuffer
 952                                                         "New UID number: "
 953                                                         (format "%s" (tar-header-uid tokens)))))))
 954                          n)
 955                        (read-string "New UID string: " (tar-header-uname tokens))))))
 956   (cond ((stringp new-uid)
 957          (tar-setf (tar-header-uname (tar-desc-tokens (tar-current-descriptor)))
 958                    new-uid)
 959          (tar-alter-one-field tar-uname-offset (concat new-uid "\000")))
 960         (t
 961          (tar-setf (tar-header-uid (tar-desc-tokens (tar-current-descriptor)))
 962                    new-uid)
 963          (tar-alter-one-field tar-uid-offset
 964            (concat (substring (format "%6o" new-uid) 0 6) "\000 ")))))
 965
 966
 967 (defun tar-chgrp-entry (new-gid)
 968   "*Change the group-id associated with this entry in the tar file.
 969 If this tar file was written by GNU tar, then you will be able to edit
 970 the group id as a string; otherwise, you must edit it as a number.
 971 You can force editing as a number by calling this with a prefix arg.
 972 This does not modify the disk image; you must save the tar file itself
 973 for this to be permanent."
 974   (interactive (list
 975                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
 976                    (if (or current-prefix-arg
 977                            (not (tar-header-magic tokens)))
 978                        (let (n)
 979                          (while (not (numberp (setq n (read-minibuffer
 980                                                         "New GID number: "
 981                                                         (format "%s" (tar-header-gid tokens)))))))
 982                          n)
 983                        (read-string "New GID string: " (tar-header-gname tokens))))))
 984   (cond ((stringp new-gid)
 985          (tar-setf (tar-header-gname (tar-desc-tokens (tar-current-descriptor)))
 986                    new-gid)
 987          (tar-alter-one-field tar-gname-offset
 988            (concat new-gid "\000")))
 989         (t
 990          (tar-setf (tar-header-gid (tar-desc-tokens (tar-current-descriptor)))
 991                    new-gid)
 992          (tar-alter-one-field tar-gid-offset
 993            (concat (substring (format "%6o" new-gid) 0 6) "\000 ")))))
 994
 995 (defun tar-rename-entry (new-name)
 996   "*Change the name associated with this entry in the tar file.
 997 This does not modify the disk image; you must save the tar file itself
 998 for this to be permanent."
 999   (interactive
1000     (list (read-string "New name: "
1001             (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
1002   (if (string= "" new-name) (error "zero length name"))
1003   (if (> (length new-name) 98) (error "name too long"))
1004   (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
1005             new-name)
1006   (tar-alter-one-field 0
1007     (substring (concat new-name (make-string 99 0)) 0 99)))
1008
1009
1010 (defun tar-chmod-entry (new-mode)
1011   "*Change the protection bits associated with this entry in the tar file.
1012 This does not modify the disk image; you must save the tar file itself
1013 for this to be permanent."
1014   (interactive (list (tar-parse-octal-integer-safe
1015                        (read-string "New protection (octal): "))))
1016   (tar-setf (tar-header-mode (tar-desc-tokens (tar-current-descriptor)))
1017             new-mode)
1018   (tar-alter-one-field tar-mode-offset
1019     (concat (substring (format "%6o" new-mode) 0 6) "\000 ")))
1020
1021
1022 (defun tar-alter-one-field (data-position new-data-string)
1023   (let* ((descriptor (tar-current-descriptor))
1024          (tokens (tar-desc-tokens descriptor)))
1025     (unwind-protect
1026         (save-excursion
1027           ;;
1028           ;; update the header-line.
1029           (beginning-of-line)
1030           (let ((p (point)))
1031             (forward-line 1)
1032             (delete-region p (point))
1033             (insert (tar-header-block-summarize tokens) "\n")
1034             (setq tar-header-offset (point-max)))
1035
1036           (widen)
1037           (let* ((start (+ (tar-desc-data-start descriptor) tar-header-offset -513)))
1038             ;;
1039             ;; delete the old field and insert a new one.
1040             (goto-char (+ start data-position))
1041             (delete-region (point) (+ (point) (length new-data-string))) ; <--
1042             (insert new-data-string) ; <--
1043             ;;
1044             ;; compute a new checksum and insert it.
1045             (let ((chk (tar-header-block-checksum
1046                         (buffer-substring start (+ start 512)))))
1047               (goto-char (+ start tar-chk-offset))
1048               (delete-region (point) (+ (point) 8))
1049               (insert (format "%6o" chk))
1050               (insert 0)
1051               (insert ? )
1052               (tar-setf (tar-header-checksum tokens) chk)
1053               ;;
1054               ;; ok, make sure we didn't botch it.
1055               (tar-header-block-check-checksum
1056                 (buffer-substring start (+ start 512))
1057                 chk (tar-header-name tokens))
1058               )))
1059       (narrow-to-region 1 tar-header-offset))))
1060
1061
1062 (defun tar-octal-time (timeval)
1063   ;; Format a timestamp as 11 octal digits.  Ghod, I hope this works...
1064   (let ((hibits (car timeval)) (lobits (car (cdr timeval))))
1065     (insert (format "%05o%01o%05o"
1066                     (lsh hibits -2)
1067                     (logior (lsh (logand 3 hibits) 1) (> (logand lobits 32768) 0))
1068                     (logand 32767 lobits)
1069                     ))))
1070
1071 (defun tar-subfile-save-buffer ()
1072   "In tar subfile mode, save this buffer into its parent tar-file buffer.
1073 This doesn't write anything to disk; you must save the parent tar-file buffer
1074 to make your changes permanent."
1075   (interactive)
1076   (if (not (and (boundp 'tar-superior-buffer) tar-superior-buffer))
1077     (error "This buffer has no superior tar file buffer"))
1078   (if (not (and (boundp 'tar-superior-descriptor) tar-superior-descriptor))
1079     (error "This buffer doesn't have an index into its superior tar file!"))
1080   (save-excursion
1081   (let ((subfile (current-buffer))
1082         (subfile-size (buffer-size))
1083         (descriptor tar-superior-descriptor))
1084     (set-buffer tar-superior-buffer)
1085     (let* ((tokens (tar-desc-tokens descriptor))
1086            (start (tar-desc-data-start descriptor))
1087            (name (tar-header-name tokens))
1088            (size (tar-header-size tokens))
1089            (size-pad (ash (ash (+ size 511) -9) 9))
1090            (head (memq descriptor tar-parse-info))
1091            (following-descs (cdr head)))
1092       (if (not head)
1093         (error "Can't find this tar file entry in its parent tar file!"))
1094       (unwind-protect
1095        (save-excursion
1096         (widen)
1097         ;; delete the old data...
1098         (let* ((data-start (+ start tar-header-offset -1))
1099                (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
1100           (delete-region data-start data-end)
1101           ;; insert the new data...
1102           (goto-char data-start)
1103           (insert-buffer subfile)
1104           ;;
1105           ;; pad the new data out to a multiple of 512...
1106           (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
1107             (goto-char (+ data-start subfile-size))
1108             (insert (make-string (- subfile-size-pad subfile-size) 0))
1109             ;;
1110             ;; update the data pointer of this and all following files...
1111             (tar-setf (tar-header-size tokens) subfile-size)
1112             (let ((difference (- subfile-size-pad size-pad)))
1113               (tar-dolist (desc following-descs)
1114                 (tar-setf (tar-desc-data-start desc)
1115                           (+ (tar-desc-data-start desc) difference))))
1116             ;;
1117             ;; Update the size field in the header block.
1118             (let ((header-start (- data-start 512)))
1119               (goto-char (+ header-start tar-size-offset))
1120               (delete-region (point) (+ (point) 12))
1121               (insert (format "%11o" subfile-size))
1122               (insert ? )
1123               ;;
1124               ;; Maybe update the datestamp.
1125               (if (not tar-update-datestamp)
1126                   nil
1127                 (goto-char (+ header-start tar-time-offset))
1128                 (delete-region (point) (+ (point) 12))
1129                 (insert (tar-octal-time (current-time)))
1130                 (insert ? ))
1131               ;;
1132               ;; compute a new checksum and insert it.
1133               (let ((chk (tar-header-block-checksum
1134                           (buffer-substring header-start data-start))))
1135                 (goto-char (+ header-start tar-chk-offset))
1136                 (delete-region (point) (+ (point) 8))
1137                 (insert (format "%6o" chk))
1138                 (insert 0)
1139                 (insert ? )
1140                 (tar-setf (tar-header-checksum tokens) chk)))
1141             ;;
1142             ;; alter the descriptor-line...
1143             ;;
1144             (let ((position (- (length tar-parse-info) (length head))))
1145               (goto-char 1)
1146               (next-line position)
1147               (beginning-of-line)
1148               (let ((p (point))
1149                     after
1150                     (m (set-marker (make-marker) tar-header-offset)))
1151                 (forward-line 1)
1152                 (setq after (point))
1153                 ;; Insert the new text after the old, before deleting,
1154                 ;; to preserve the window start.
1155                 (insert-before-markers (tar-header-block-summarize tokens t) "\n")
1156                 (delete-region p after)
1157                 (setq tar-header-offset (marker-position m)))
1158               )))
1159         ;; after doing the insertion, add any final padding that may be necessary.
1160         (tar-pad-to-blocksize))
1161        (narrow-to-region 1 tar-header-offset)))
1162     (set-buffer-modified-p t)   ; mark the tar file as modified
1163     (set-buffer subfile)
1164     (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
1165     (message "Saved into tar-buffer `%s'.  Be sure to save that buffer!"
1166              (buffer-name tar-superior-buffer))
1167     ;; Prevent ordinary saving from happening.
1168     t)))
1169
1170
1171 (defun tar-pad-to-blocksize ()
1172   "If we are being anal about tar file blocksizes, fix up the current buffer.
1173 Leaves the region wide."
1174   (if (null tar-anal-blocksize)
1175       nil
1176     (widen)
1177     (let* ((last-desc (nth (1- (length tar-parse-info)) tar-parse-info))
1178            (start (tar-desc-data-start last-desc))
1179            (tokens (tar-desc-tokens last-desc))
1180            (link-p (tar-header-link-type tokens))
1181            (size (if link-p 0 (tar-header-size tokens)))
1182            (data-end (+ start size))
1183            (bbytes (ash tar-anal-blocksize 9))
1184            (pad-to (+ bbytes (* bbytes (/ (1- data-end) bbytes))))
1185            (inhibit-read-only t) ; ##
1186            )
1187       ;; If the padding after the last data is too long, delete some;
1188       ;; else insert some until we are padded out to the right number of blocks.
1189       ;;
1190       (goto-char (+ (or tar-header-offset 0) data-end))
1191       (if (> (1+ (buffer-size)) (+ (or tar-header-offset 0) pad-to))
1192           (delete-region (+ (or tar-header-offset 0) pad-to) (1+ (buffer-size)))
1193           (insert (make-string (- (+ (or tar-header-offset 0) pad-to)
1194                                   (1+ (buffer-size)))
1195                                0)))
1196       )))
1197
1198
1199 ;; Used in write-file-hook to write tar-files out correctly.
1200 (defun tar-mode-write-file ()
1201   (unwind-protect
1202       (save-excursion
1203         (widen)
1204         ;; Doing this here confuses things - the region gets left too wide!
1205         ;; I suppose this is run in a context where changing the buffer is bad.
1206         ;; (tar-pad-to-blocksize)
1207         (write-region tar-header-offset (point-max) buffer-file-name nil t)
1208         (tar-clear-modification-flags)
1209         (set-buffer-modified-p nil))
1210     (narrow-to-region 1 tar-header-offset))
1211   ;; return T because we've written the file.
1212   t)
1213
1214 (defun tar-quit ()
1215   "Kill the current tar buffer."
1216   (interactive)
1217   (kill-buffer nil))
1218
1219 \f
1220 (provide 'tar-mode)
1221
1222 ;;; tar-mode.el ends here