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[emacs.git] / lisp / tar-mode.el
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1 ;;; tar-mode.el --- simple editing of tar files from GNU emacs
3 ;; Copyright (C) 1990, 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
5 ;; Author: Jamie Zawinski <jwz@lucid.com>
6 ;; Maintainer: FSF
7 ;; Created: 04 Apr 1990
8 ;; Keywords: unix
10 ;; This file is part of GNU Emacs.
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.
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.
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.
27 ;;; Commentary:
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.
40 ;; This code now understands the extra fields that GNU tar adds to tar files.
42 ;; This interacts correctly with "uncompress.el" in the Emacs library,
43 ;; which you get with
45 ;; (autoload 'uncompress-while-visiting "uncompress")
46 ;; (setq auto-mode-alist (cons '("\\.Z$" . uncompress-while-visiting)
47 ;; auto-mode-alist))
49 ;; Do not attempt to use tar-mode.el with crypt.el, you will lose.
51 ;; *************** TO DO ***************
53 ;; o chmod should understand "a+x,og-w".
55 ;; o It's not possible to add a NEW file to a tar archive; not that
56 ;; important, but still...
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.
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.)
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.
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.
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.
81 ;; Rationale:
83 ;; Why does tar-mode edit the file itself instead of using tar?
85 ;; That means that you can edit tar files which you don't have room for
86 ;; on your local disk.
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.
95 ;;; Code:
97 (defgroup tar nil
98 "Simple editing of tar files."
99 :prefix "tar-"
100 :group 'data)
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)
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)
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)
130 (defvar tar-parse-info nil)
131 ;; Be sure that this variable holds byte position, not char position.
132 (defvar tar-header-offset nil)
133 (defvar tar-superior-buffer nil)
134 (defvar tar-superior-descriptor nil)
135 (defvar tar-subfile-mode nil)
137 (put 'tar-parse-info 'permanent-local t)
138 (put 'tar-header-offset 'permanent-local t)
139 (put 'tar-superior-buffer 'permanent-local t)
140 (put 'tar-superior-descriptor 'permanent-local t)
142 (defmacro tar-setf (form val)
143 "A mind-numbingly simple implementation of setf."
144 (let ((mform (macroexpand form (and (boundp 'byte-compile-macro-environment)
145 byte-compile-macro-environment))))
146 (cond ((symbolp mform) (list 'setq mform val))
147 ((not (consp mform)) (error "can't setf %s" form))
148 ((eq (car mform) 'aref)
149 (list 'aset (nth 1 mform) (nth 2 mform) val))
150 ((eq (car mform) 'car)
151 (list 'setcar (nth 1 mform) val))
152 ((eq (car mform) 'cdr)
153 (list 'setcdr (nth 1 mform) val))
154 (t (error "don't know how to setf %s" form)))))
156 ;;; down to business.
158 (defmacro make-tar-header (name mode uid git size date ck lt ln
159 magic uname gname devmaj devmin)
160 (list 'vector name mode uid git size date ck lt ln
161 magic uname gname devmaj devmin))
163 (defmacro tar-header-name (x) (list 'aref x 0))
164 (defmacro tar-header-mode (x) (list 'aref x 1))
165 (defmacro tar-header-uid (x) (list 'aref x 2))
166 (defmacro tar-header-gid (x) (list 'aref x 3))
167 (defmacro tar-header-size (x) (list 'aref x 4))
168 (defmacro tar-header-date (x) (list 'aref x 5))
169 (defmacro tar-header-checksum (x) (list 'aref x 6))
170 (defmacro tar-header-link-type (x) (list 'aref x 7))
171 (defmacro tar-header-link-name (x) (list 'aref x 8))
172 (defmacro tar-header-magic (x) (list 'aref x 9))
173 (defmacro tar-header-uname (x) (list 'aref x 10))
174 (defmacro tar-header-gname (x) (list 'aref x 11))
175 (defmacro tar-header-dmaj (x) (list 'aref x 12))
176 (defmacro tar-header-dmin (x) (list 'aref x 13))
178 (defmacro make-tar-desc (data-start tokens)
179 (list 'cons data-start tokens))
181 (defmacro tar-desc-data-start (x) (list 'car x))
182 (defmacro tar-desc-tokens (x) (list 'cdr x))
184 (defconst tar-name-offset 0)
185 (defconst tar-mode-offset (+ tar-name-offset 100))
186 (defconst tar-uid-offset (+ tar-mode-offset 8))
187 (defconst tar-gid-offset (+ tar-uid-offset 8))
188 (defconst tar-size-offset (+ tar-gid-offset 8))
189 (defconst tar-time-offset (+ tar-size-offset 12))
190 (defconst tar-chk-offset (+ tar-time-offset 12))
191 (defconst tar-linkp-offset (+ tar-chk-offset 8))
192 (defconst tar-link-offset (+ tar-linkp-offset 1))
193 ;;; GNU-tar specific slots.
194 (defconst tar-magic-offset (+ tar-link-offset 100))
195 (defconst tar-uname-offset (+ tar-magic-offset 8))
196 (defconst tar-gname-offset (+ tar-uname-offset 32))
197 (defconst tar-dmaj-offset (+ tar-gname-offset 32))
198 (defconst tar-dmin-offset (+ tar-dmaj-offset 8))
199 (defconst tar-end-offset (+ tar-dmin-offset 8))
201 (defun tar-header-block-tokenize (string)
202 "Return a `tar-header' structure.
203 This is a list of name, mode, uid, gid, size,
204 write-date, checksum, link-type, and link-name."
205 (cond ((< (length string) 512) nil)
206 (;(some 'plusp string) ; <-- oops, massive cycle hog!
207 (or (not (= 0 (aref string 0))) ; This will do.
208 (not (= 0 (aref string 101))))
209 (let* ((name-end (1- tar-mode-offset))
210 (link-end (1- tar-magic-offset))
211 (uname-end (1- tar-gname-offset))
212 (gname-end (1- tar-dmaj-offset))
213 (link-p (aref string tar-linkp-offset))
214 (magic-str (substring string tar-magic-offset (1- tar-uname-offset)))
215 (uname-valid-p (or (string= "ustar " magic-str) (string= "GNUtar " magic-str)))
216 name linkname
217 (nulsexp "[^\000]*\000"))
218 (when (string-match nulsexp string tar-name-offset)
219 (setq name-end (min name-end (1- (match-end 0)))))
220 (when (string-match nulsexp string tar-link-offset)
221 (setq link-end (min link-end (1- (match-end 0)))))
222 (when (string-match nulsexp string tar-uname-offset)
223 (setq uname-end (min uname-end (1- (match-end 0)))))
224 (when (string-match nulsexp string tar-gname-offset)
225 (setq gname-end (min gname-end (1- (match-end 0)))))
226 (setq name (substring string tar-name-offset name-end)
227 link-p (if (or (= link-p 0) (= link-p ?0))
229 (- link-p ?0)))
230 (setq linkname (substring string tar-link-offset link-end))
231 (if default-enable-multibyte-characters
232 (setq name
233 (decode-coding-string name (or file-name-coding-system
234 'undecided))
235 linkname
236 (decode-coding-string linkname (or file-name-coding-system
237 'undecided))))
238 (if (and (null link-p) (string-match "/$" name)) (setq link-p 5)) ; directory
239 (make-tar-header
240 name
241 (tar-parse-octal-integer string tar-mode-offset tar-uid-offset)
242 (tar-parse-octal-integer string tar-uid-offset tar-gid-offset)
243 (tar-parse-octal-integer string tar-gid-offset tar-size-offset)
244 (tar-parse-octal-integer string tar-size-offset tar-time-offset)
245 (tar-parse-octal-long-integer string tar-time-offset tar-chk-offset)
246 (tar-parse-octal-integer string tar-chk-offset tar-linkp-offset)
247 link-p
248 linkname
249 uname-valid-p
250 (and uname-valid-p (substring string tar-uname-offset uname-end))
251 (and uname-valid-p (substring string tar-gname-offset gname-end))
252 (tar-parse-octal-integer string tar-dmaj-offset tar-dmin-offset)
253 (tar-parse-octal-integer string tar-dmin-offset tar-end-offset)
255 (t 'empty-tar-block)))
258 (defun tar-parse-octal-integer (string &optional start end)
259 (if (null start) (setq start 0))
260 (if (null end) (setq end (length string)))
261 (if (= (aref string start) 0)
263 (let ((n 0))
264 (while (< start end)
265 (setq n (if (< (aref string start) ?0) n
266 (+ (* n 8) (- (aref string start) ?0)))
267 start (1+ start)))
268 n)))
270 (defun tar-parse-octal-long-integer (string &optional start end)
271 (if (null start) (setq start 0))
272 (if (null end) (setq end (length string)))
273 (if (= (aref string start) 0)
274 (list 0 0)
275 (let ((lo 0)
276 (hi 0))
277 (while (< start end)
278 (if (>= (aref string start) ?0)
279 (setq lo (+ (* lo 8) (- (aref string start) ?0))
280 hi (+ (* hi 8) (ash lo -16))
281 lo (logand lo 65535)))
282 (setq start (1+ start)))
283 (list hi lo))))
285 (defun tar-parse-octal-integer-safe (string)
286 (let ((L (length string)))
287 (if (= L 0) (error "empty string"))
288 (dotimes (i L)
289 (if (or (< (aref string i) ?0)
290 (> (aref string i) ?7))
291 (error "`%c' is not an octal digit"))))
292 (tar-parse-octal-integer string))
295 (defun tar-header-block-checksum (string)
296 "Compute and return a tar-acceptable checksum for this block."
297 (let* ((chk-field-start tar-chk-offset)
298 (chk-field-end (+ chk-field-start 8))
299 (sum 0)
300 (i 0))
301 ;; Add up all of the characters except the ones in the checksum field.
302 ;; Add that field as if it were filled with spaces.
303 (while (< i chk-field-start)
304 (setq sum (+ sum (aref string i))
305 i (1+ i)))
306 (setq i chk-field-end)
307 (while (< i 512)
308 (setq sum (+ sum (aref string i))
309 i (1+ i)))
310 (+ sum (* 32 8))))
312 (defun tar-header-block-check-checksum (hblock desired-checksum file-name)
313 "Beep and print a warning if the checksum doesn't match."
314 (if (not (= desired-checksum (tar-header-block-checksum hblock)))
315 (progn (beep) (message "Invalid checksum for file %s!" file-name))))
317 (defun tar-clip-time-string (time)
318 (let ((str (current-time-string time)))
319 (concat " " (substring str 4 16) (substring str 19 24))))
321 (defun tar-grind-file-mode (mode)
322 "Construct a `-rw--r--r--' string indicating MODE.
323 MODE should be an integer which is a file mode value."
324 (string
325 (if (zerop (logand 256 mode)) ?- ?r)
326 (if (zerop (logand 128 mode)) ?- ?w)
327 (if (zerop (logand 1024 mode)) (if (zerop (logand 64 mode)) ?- ?x) ?s)
328 (if (zerop (logand 32 mode)) ?- ?r)
329 (if (zerop (logand 16 mode)) ?- ?w)
330 (if (zerop (logand 2048 mode)) (if (zerop (logand 8 mode)) ?- ?x) ?s)
331 (if (zerop (logand 4 mode)) ?- ?r)
332 (if (zerop (logand 2 mode)) ?- ?w)
333 (if (zerop (logand 1 mode)) ?- ?x)))
335 (defun tar-header-block-summarize (tar-hblock &optional mod-p)
336 "Return a line similar to the output of `tar -vtf'."
337 (let ((name (tar-header-name tar-hblock))
338 (mode (tar-header-mode tar-hblock))
339 (uid (tar-header-uid tar-hblock))
340 (gid (tar-header-gid tar-hblock))
341 (uname (tar-header-uname tar-hblock))
342 (gname (tar-header-gname tar-hblock))
343 (size (tar-header-size tar-hblock))
344 (time (tar-header-date tar-hblock))
345 (ck (tar-header-checksum tar-hblock))
346 (type (tar-header-link-type tar-hblock))
347 (link-name (tar-header-link-name tar-hblock)))
348 (format "%c%c%s%8s/%-8s%7s%s %s%s"
349 (if mod-p ?* ? )
350 (cond ((or (eq type nil) (eq type 0)) ?-)
351 ((eq type 1) ?l) ; link
352 ((eq type 2) ?s) ; symlink
353 ((eq type 3) ?c) ; char special
354 ((eq type 4) ?b) ; block special
355 ((eq type 5) ?d) ; directory
356 ((eq type 6) ?p) ; FIFO/pipe
357 ((eq type 20) ?*) ; directory listing
358 ((eq type 29) ?M) ; multivolume continuation
359 ((eq type 35) ?S) ; sparse
360 ((eq type 38) ?V) ; volume header
361 (t ?\ )
363 (tar-grind-file-mode mode)
364 (if (= 0 (length uname)) uid uname)
365 (if (= 0 (length gname)) gid gname)
366 size
367 (if tar-mode-show-date (tar-clip-time-string time) "")
368 (propertize name 'mouse-face 'highlight)
369 (if (or (eq type 1) (eq type 2))
370 (concat (if (= type 1) " ==> " " --> ") link-name)
371 ""))))
373 (defun tar-summarize-buffer ()
374 "Parse the contents of the tar file in the current buffer.
375 Place a dired-like listing on the front;
376 then narrow to it, so that only that listing
377 is visible (and the real data of the buffer is hidden)."
378 (set-buffer-multibyte nil)
379 (message "Parsing tar file...")
380 (let* ((result '())
381 (pos 1)
382 (bs (max 1 (- (buffer-size) 1024))) ; always 2+ empty blocks at end.
383 (bs100 (max 1 (/ bs 100)))
384 tokens)
385 (while (and (<= (+ pos 512) (point-max))
386 (not (eq 'empty-tar-block
387 (setq tokens
388 (tar-header-block-tokenize
389 (buffer-substring pos (+ pos 512)))))))
390 (setq pos (+ pos 512))
391 (message "Parsing tar file...%d%%"
392 ;(/ (* pos 100) bs) ; this gets round-off lossage
393 (/ pos bs100) ; this doesn't
395 (if (eq (tar-header-link-type tokens) 20)
396 ;; Foo. There's an extra empty block after these.
397 (setq pos (+ pos 512)))
398 (let ((size (tar-header-size tokens)))
399 (if (< size 0)
400 (error "%s has size %s - corrupted"
401 (tar-header-name tokens) size))
403 ; This is just too slow. Don't really need it anyway....
404 ;(tar-header-block-check-checksum
405 ; hblock (tar-header-block-checksum hblock)
406 ; (tar-header-name tokens))
408 (setq result (cons (make-tar-desc pos tokens) result))
410 (and (null (tar-header-link-type tokens))
411 (> size 0)
412 (setq pos
413 (+ pos 512 (ash (ash (1- size) -9) 9)) ; this works
414 ;(+ pos (+ size (- 512 (rem (1- size) 512)))) ; this doesn't
415 ))))
416 (make-local-variable 'tar-parse-info)
417 (setq tar-parse-info (nreverse result))
418 ;; A tar file should end with a block or two of nulls,
419 ;; but let's not get a fatal error if it doesn't.
420 (if (eq tokens 'empty-tar-block)
421 (message "Parsing tar file...done")
422 (message "Warning: premature EOF parsing tar file")))
423 (save-excursion
424 (goto-char (point-min))
425 (let ((buffer-read-only nil)
426 (summaries nil))
427 ;; Collect summary lines and insert them all at once since tar files
428 ;; can be pretty big.
429 (dolist (tar-desc (reverse tar-parse-info))
430 (setq summaries
431 (cons (tar-header-block-summarize (tar-desc-tokens tar-desc))
432 (cons "\n"
433 summaries))))
434 (let ((total-summaries (apply 'concat summaries)))
435 (if (multibyte-string-p total-summaries)
436 (set-buffer-multibyte t))
437 (insert total-summaries))
438 (make-local-variable 'tar-header-offset)
439 (setq tar-header-offset (point))
440 (narrow-to-region 1 tar-header-offset)
441 (if enable-multibyte-characters
442 (setq tar-header-offset (position-bytes tar-header-offset)))
443 (set-buffer-modified-p nil))))
445 (defvar tar-mode-map nil "*Local keymap for Tar mode listings.")
447 (if tar-mode-map
449 (setq tar-mode-map (make-keymap))
450 (suppress-keymap tar-mode-map)
451 (define-key tar-mode-map " " 'tar-next-line)
452 (define-key tar-mode-map "C" 'tar-copy)
453 (define-key tar-mode-map "d" 'tar-flag-deleted)
454 (define-key tar-mode-map "\^D" 'tar-flag-deleted)
455 (define-key tar-mode-map "e" 'tar-extract)
456 (define-key tar-mode-map "f" 'tar-extract)
457 (define-key tar-mode-map "\C-m" 'tar-extract)
458 (define-key tar-mode-map [mouse-2] 'tar-mouse-extract)
459 (define-key tar-mode-map "g" 'revert-buffer)
460 (define-key tar-mode-map "h" 'describe-mode)
461 (define-key tar-mode-map "n" 'tar-next-line)
462 (define-key tar-mode-map "\^N" 'tar-next-line)
463 (define-key tar-mode-map [down] 'tar-next-line)
464 (define-key tar-mode-map "o" 'tar-extract-other-window)
465 (define-key tar-mode-map "p" 'tar-previous-line)
466 (define-key tar-mode-map "q" 'quit-window)
467 (define-key tar-mode-map "\^P" 'tar-previous-line)
468 (define-key tar-mode-map [up] 'tar-previous-line)
469 (define-key tar-mode-map "R" 'tar-rename-entry)
470 (define-key tar-mode-map "u" 'tar-unflag)
471 (define-key tar-mode-map "v" 'tar-view)
472 (define-key tar-mode-map "x" 'tar-expunge)
473 (define-key tar-mode-map "\177" 'tar-unflag-backwards)
474 (define-key tar-mode-map "E" 'tar-extract-other-window)
475 (define-key tar-mode-map "M" 'tar-chmod-entry)
476 (define-key tar-mode-map "G" 'tar-chgrp-entry)
477 (define-key tar-mode-map "O" 'tar-chown-entry)
480 ;; Make menu bar items.
482 ;; Get rid of the Edit menu bar item to save space.
483 (define-key tar-mode-map [menu-bar edit] 'undefined)
485 (define-key tar-mode-map [menu-bar immediate]
486 (cons "Immediate" (make-sparse-keymap "Immediate")))
488 (define-key tar-mode-map [menu-bar immediate view]
489 '("View This File" . tar-view))
490 (define-key tar-mode-map [menu-bar immediate display]
491 '("Display in Other Window" . tar-display-other-window))
492 (define-key tar-mode-map [menu-bar immediate find-file-other-window]
493 '("Find in Other Window" . tar-extract-other-window))
494 (define-key tar-mode-map [menu-bar immediate find-file]
495 '("Find This File" . tar-extract))
497 (define-key tar-mode-map [menu-bar mark]
498 (cons "Mark" (make-sparse-keymap "Mark")))
500 (define-key tar-mode-map [menu-bar mark unmark-all]
501 '("Unmark All" . tar-clear-modification-flags))
502 (define-key tar-mode-map [menu-bar mark deletion]
503 '("Flag" . tar-flag-deleted))
504 (define-key tar-mode-map [menu-bar mark unmark]
505 '("Unflag" . tar-unflag))
507 (define-key tar-mode-map [menu-bar operate]
508 (cons "Operate" (make-sparse-keymap "Operate")))
510 (define-key tar-mode-map [menu-bar operate chown]
511 '("Change Owner..." . tar-chown-entry))
512 (define-key tar-mode-map [menu-bar operate chgrp]
513 '("Change Group..." . tar-chgrp-entry))
514 (define-key tar-mode-map [menu-bar operate chmod]
515 '("Change Mode..." . tar-chmod-entry))
516 (define-key tar-mode-map [menu-bar operate rename]
517 '("Rename to..." . tar-rename-entry))
518 (define-key tar-mode-map [menu-bar operate copy]
519 '("Copy to..." . tar-copy))
520 (define-key tar-mode-map [menu-bar operate expunge]
521 '("Expunge Marked Files" . tar-expunge))
523 ;; tar mode is suitable only for specially formatted data.
524 (put 'tar-mode 'mode-class 'special)
525 (put 'tar-subfile-mode 'mode-class 'special)
527 ;;;###autoload
528 (defun tar-mode ()
529 "Major mode for viewing a tar file as a dired-like listing of its contents.
530 You can move around using the usual cursor motion commands.
531 Letters no longer insert themselves.
532 Type `e' to pull a file out of the tar file and into its own buffer;
533 or click mouse-2 on the file's line in the Tar mode buffer.
534 Type `c' to copy an entry from the tar file into another file on disk.
536 If you edit a sub-file of this archive (as with the `e' command) and
537 save it with Control-x Control-s, the contents of that buffer will be
538 saved back into the tar-file buffer; in this way you can edit a file
539 inside of a tar archive without extracting it and re-archiving it.
541 See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
542 \\{tar-mode-map}"
543 ;; this is not interactive because you shouldn't be turning this
544 ;; mode on and off. You can corrupt things that way.
545 ;; rms: with permanent locals, it should now be possible to make this work
546 ;; interactively in some reasonable fashion.
547 (kill-all-local-variables)
548 (make-local-variable 'tar-header-offset)
549 (make-local-variable 'tar-parse-info)
550 (make-local-variable 'require-final-newline)
551 (setq require-final-newline nil) ; binary data, dude...
552 (make-local-variable 'revert-buffer-function)
553 (setq revert-buffer-function 'tar-mode-revert)
554 (make-local-variable 'local-enable-local-variables)
555 (setq local-enable-local-variables nil)
556 (make-local-variable 'next-line-add-newlines)
557 (setq next-line-add-newlines nil)
558 ;; Prevent loss of data when saving the file.
559 (make-local-variable 'file-precious-flag)
560 (setq file-precious-flag t)
561 (setq major-mode 'tar-mode)
562 (setq mode-name "Tar")
563 (use-local-map tar-mode-map)
564 (auto-save-mode 0)
565 (make-local-variable 'write-contents-hooks)
566 (setq write-contents-hooks '(tar-mode-write-file))
567 (widen)
568 (if (and (boundp 'tar-header-offset) tar-header-offset)
569 (narrow-to-region 1 (byte-to-position tar-header-offset))
570 (tar-summarize-buffer)
571 (tar-next-line 0))
572 (run-hooks 'tar-mode-hook)
576 (defun tar-subfile-mode (p)
577 "Minor mode for editing an element of a tar-file.
578 This mode arranges for \"saving\" this buffer to write the data
579 into the tar-file buffer that it came from. The changes will actually
580 appear on disk when you save the tar-file's buffer."
581 (interactive "P")
582 (or (and (boundp 'tar-superior-buffer) tar-superior-buffer)
583 (error "This buffer is not an element of a tar file"))
584 ;;; Don't do this, because it is redundant and wastes mode line space.
585 ;;; (or (assq 'tar-subfile-mode minor-mode-alist)
586 ;;; (setq minor-mode-alist (append minor-mode-alist
587 ;;; (list '(tar-subfile-mode " TarFile")))))
588 (make-local-variable 'tar-subfile-mode)
589 (setq tar-subfile-mode
590 (if (null p)
591 (not tar-subfile-mode)
592 (> (prefix-numeric-value p) 0)))
593 (cond (tar-subfile-mode
594 (make-local-variable 'local-write-file-hooks)
595 (setq local-write-file-hooks '(tar-subfile-save-buffer))
596 ;; turn off auto-save.
597 (auto-save-mode -1)
598 (setq buffer-auto-save-file-name nil)
599 (run-hooks 'tar-subfile-mode-hook))
601 (kill-local-variable 'local-write-file-hooks))))
604 ;; Revert the buffer and recompute the dired-like listing.
605 (defun tar-mode-revert (&optional no-auto-save no-confirm)
606 (let ((revert-buffer-function nil)
607 (old-offset tar-header-offset)
608 success)
609 (setq tar-header-offset nil)
610 (unwind-protect
611 (and (revert-buffer t no-confirm)
612 (progn (widen)
613 (setq success t)
614 (tar-mode)))
615 ;; If the revert was canceled,
616 ;; put back the old value of tar-header-offset.
617 (or success
618 (setq tar-header-offset old-offset)))))
621 (defun tar-next-line (p)
622 (interactive "p")
623 (forward-line p)
624 (if (eobp) nil (forward-char (if tar-mode-show-date 54 36))))
626 (defun tar-previous-line (p)
627 (interactive "p")
628 (tar-next-line (- p)))
630 (defun tar-current-descriptor (&optional noerror)
631 "Return the tar-descriptor of the current line, or signals an error."
632 ;; I wish lines had plists, like in ZMACS...
633 (or (nth (count-lines (point-min)
634 (save-excursion (beginning-of-line) (point)))
635 tar-parse-info)
636 (if noerror
638 (error "This line does not describe a tar-file entry"))))
640 (defun tar-get-descriptor ()
641 (let* ((descriptor (tar-current-descriptor))
642 (tokens (tar-desc-tokens descriptor))
643 (size (tar-header-size tokens))
644 (link-p (tar-header-link-type tokens)))
645 (if link-p
646 (error "This is a %s, not a real file"
647 (cond ((eq link-p 5) "directory")
648 ((eq link-p 20) "tar directory header")
649 ((eq link-p 29) "multivolume-continuation")
650 ((eq link-p 35) "sparse entry")
651 ((eq link-p 38) "volume header")
652 (t "link"))))
653 (if (zerop size) (error "This is a zero-length file"))
654 descriptor))
656 (defun tar-mouse-extract (event)
657 "Extract a file whose tar directory line you click on."
658 (interactive "e")
659 (save-excursion
660 (set-buffer (window-buffer (posn-window (event-end event))))
661 (save-excursion
662 (goto-char (posn-point (event-end event)))
663 ;; Just make sure this doesn't get an error.
664 (tar-get-descriptor)))
665 (select-window (posn-window (event-end event)))
666 (goto-char (posn-point (event-end event)))
667 (tar-extract))
669 (defun tar-extract (&optional other-window-p)
670 "In Tar mode, extract this entry of the tar file into its own buffer."
671 (interactive)
672 (let* ((view-p (eq other-window-p 'view))
673 (descriptor (tar-get-descriptor))
674 (tokens (tar-desc-tokens descriptor))
675 (name (tar-header-name tokens))
676 (size (tar-header-size tokens))
677 (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
678 (end (+ start size)))
679 (let* ((tar-buffer (current-buffer))
680 (tar-buffer-multibyte enable-multibyte-characters)
681 (tarname (if (buffer-file-name)
682 (file-name-nondirectory (buffer-file-name))
683 (buffer-name)))
684 (bufname (concat (file-name-nondirectory name)
685 " ("
686 tarname
687 ")"))
688 (read-only-p (or buffer-read-only view-p))
689 (buffer (get-buffer bufname))
690 (just-created nil))
691 (if buffer
693 (setq buffer (get-buffer-create bufname))
694 (setq just-created t)
695 (unwind-protect
696 (progn
697 (widen)
698 (set-buffer-multibyte nil)
699 (save-excursion
700 (set-buffer buffer)
701 (if enable-multibyte-characters
702 (progn
703 ;; We must avoid unibyte->multibyte conversion.
704 (set-buffer-multibyte nil)
705 (insert-buffer-substring tar-buffer start end)
706 (set-buffer-multibyte t))
707 (insert-buffer-substring tar-buffer start end))
708 (goto-char (point-min))
709 (setq buffer-file-name
710 ;; `:' is not allowed on Windows
711 (expand-file-name (concat tarname "!" name)))
712 (setq buffer-file-truename
713 (abbreviate-file-name buffer-file-name))
714 ;; We need to mimic the parts of insert-file-contents
715 ;; which determine the coding-system and decode the text.
716 (let ((coding
717 (and set-auto-coding-function
718 (save-excursion
719 (funcall set-auto-coding-function
720 name (- (point-max) (point))))))
721 (multibyte enable-multibyte-characters)
722 (detected (detect-coding-region
723 1 (min 16384 (point-max)) t)))
724 (if coding
725 (or (numberp (coding-system-eol-type coding))
726 (setq coding (coding-system-change-eol-conversion
727 coding
728 (coding-system-eol-type detected))))
729 (setq coding
730 (or (find-new-buffer-file-coding-system detected)
731 (let ((file-coding
732 (find-operation-coding-system
733 'insert-file-contents buffer-file-name)))
734 (if (consp file-coding)
735 (setq file-coding (car file-coding))
736 file-coding)))))
737 (if (or (eq coding 'no-conversion)
738 (eq (coding-system-type coding) 5))
739 (setq multibyte (set-buffer-multibyte nil)))
740 (or multibyte
741 (setq coding
742 (coding-system-change-text-conversion
743 coding 'raw-text)))
744 (decode-coding-region 1 (point-max) coding)
745 (set-buffer-file-coding-system coding))
746 ;; Set the default-directory to the dir of the
747 ;; superior buffer.
748 (setq default-directory
749 (save-excursion
750 (set-buffer tar-buffer)
751 default-directory))
752 (normal-mode) ; pick a mode.
753 (rename-buffer bufname)
754 (make-local-variable 'tar-superior-buffer)
755 (make-local-variable 'tar-superior-descriptor)
756 (setq tar-superior-buffer tar-buffer)
757 (setq tar-superior-descriptor descriptor)
758 (setq buffer-read-only read-only-p)
759 (set-buffer-modified-p nil)
760 (tar-subfile-mode 1))
761 (set-buffer tar-buffer))
762 (narrow-to-region 1 tar-header-offset)
763 (set-buffer-multibyte tar-buffer-multibyte)))
764 (if view-p
765 (view-buffer buffer (and just-created 'kill-buffer))
766 (if (eq other-window-p 'display)
767 (display-buffer buffer)
768 (if other-window-p
769 (switch-to-buffer-other-window buffer)
770 (switch-to-buffer buffer)))))))
773 (defun tar-extract-other-window ()
774 "*In Tar mode, find this entry of the tar file in another window."
775 (interactive)
776 (tar-extract t))
778 (defun tar-display-other-window ()
779 "*In Tar mode, display this entry of the tar file in another window."
780 (interactive)
781 (tar-extract 'display))
783 (defun tar-view ()
784 "*In Tar mode, view the tar file entry on this line."
785 (interactive)
786 (tar-extract 'view))
789 (defun tar-read-file-name (&optional prompt)
790 "Read a file name with this line's entry as the default."
791 (or prompt (setq prompt "Copy to: "))
792 (let* ((default-file (expand-file-name
793 (tar-header-name (tar-desc-tokens
794 (tar-current-descriptor)))))
795 (target (expand-file-name
796 (read-file-name prompt
797 (file-name-directory default-file)
798 default-file nil))))
799 (if (or (string= "" (file-name-nondirectory target))
800 (file-directory-p target))
801 (setq target (concat (if (string-match "/$" target)
802 (substring target 0 (1- (match-end 0)))
803 target)
805 (file-name-nondirectory default-file))))
806 target))
809 (defun tar-copy (&optional to-file)
810 "*In Tar mode, extract this entry of the tar file into a file on disk.
811 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
812 the current tar-entry."
813 (interactive (list (tar-read-file-name)))
814 (let* ((descriptor (tar-get-descriptor))
815 (tokens (tar-desc-tokens descriptor))
816 (name (tar-header-name tokens))
817 (size (tar-header-size tokens))
818 (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
819 (end (+ start size))
820 (multibyte enable-multibyte-characters)
821 (inhibit-file-name-handlers inhibit-file-name-handlers)
822 (inhibit-file-name-operation inhibit-file-name-operation))
823 (save-restriction
824 (widen)
825 ;; Inhibit compressing a subfile again if *both* name and
826 ;; to-file are handled by jka-compr
827 (if (and (eq (find-file-name-handler name 'write-region) 'jka-compr-handler)
828 (eq (find-file-name-handler to-file 'write-region) 'jka-compr-handler))
829 (setq inhibit-file-name-handlers
830 (cons 'jka-compr-handler
831 (and (eq inhibit-file-name-operation 'write-region)
832 inhibit-file-name-handlers))
833 inhibit-file-name-operation 'write-region))
834 (unwind-protect
835 (let ((coding-system-for-write 'no-conversion))
836 (set-buffer-multibyte nil)
837 (write-region start end to-file nil nil nil t))
838 (set-buffer-multibyte multibyte)))
839 (message "Copied tar entry %s to %s" name to-file)))
841 (defun tar-flag-deleted (p &optional unflag)
842 "*In Tar mode, mark this sub-file to be deleted from the tar file.
843 With a prefix argument, mark that many files."
844 (interactive "p")
845 (beginning-of-line)
846 (dotimes (i (if (< p 0) (- p) p))
847 (if (tar-current-descriptor unflag) ; barf if we're not on an entry-line.
848 (progn
849 (delete-char 1)
850 (insert (if unflag " " "D"))))
851 (forward-line (if (< p 0) -1 1)))
852 (if (eobp) nil (forward-char 36)))
854 (defun tar-unflag (p)
855 "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
856 With a prefix argument, un-mark that many files forward."
857 (interactive "p")
858 (tar-flag-deleted p t))
860 (defun tar-unflag-backwards (p)
861 "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
862 With a prefix argument, un-mark that many files backward."
863 (interactive "p")
864 (tar-flag-deleted (- p) t))
867 ;; When this function is called, it is sure that the buffer is unibyte.
868 (defun tar-expunge-internal ()
869 "Expunge the tar-entry specified by the current line."
870 (let* ((descriptor (tar-current-descriptor))
871 (tokens (tar-desc-tokens descriptor))
872 (line (tar-desc-data-start descriptor))
873 (name (tar-header-name tokens))
874 (size (tar-header-size tokens))
875 (link-p (tar-header-link-type tokens))
876 (start (tar-desc-data-start descriptor))
877 (following-descs (cdr (memq descriptor tar-parse-info))))
878 (if link-p (setq size 0)) ; size lies for hard-links.
880 ;; delete the current line...
881 (beginning-of-line)
882 (let ((line-start (point)))
883 (end-of-line) (forward-char)
884 (let ((line-len (- (point) line-start)))
885 (delete-region line-start (point))
887 ;; decrement the header-pointer to be in sync...
888 (setq tar-header-offset (- tar-header-offset line-len))))
890 ;; delete the data pointer...
891 (setq tar-parse-info (delq descriptor tar-parse-info))
893 ;; delete the data from inside the file...
894 (widen)
895 (let* ((data-start (+ start tar-header-offset -513))
896 (data-end (+ data-start 512 (ash (ash (+ size 511) -9) 9))))
897 (delete-region data-start data-end)
899 ;; and finally, decrement the start-pointers of all following
900 ;; entries in the archive. This is a pig when deleting a bunch
901 ;; of files at once - we could optimize this to only do the
902 ;; iteration over the files that remain, or only iterate up to
903 ;; the next file to be deleted.
904 (let ((data-length (- data-end data-start)))
905 (dolist (desc following-descs)
906 (tar-setf (tar-desc-data-start desc)
907 (- (tar-desc-data-start desc) data-length))))
909 (narrow-to-region 1 tar-header-offset))
912 (defun tar-expunge (&optional noconfirm)
913 "*In Tar mode, delete all the archived files flagged for deletion.
914 This does not modify the disk image; you must save the tar file itself
915 for this to be permanent."
916 (interactive)
917 (if (or noconfirm
918 (y-or-n-p "Expunge files marked for deletion? "))
919 (let ((n 0)
920 (multibyte enable-multibyte-characters))
921 (set-buffer-multibyte nil)
922 (save-excursion
923 (goto-char (point-min))
924 (while (not (eobp))
925 (if (looking-at "D")
926 (progn (tar-expunge-internal)
927 (setq n (1+ n)))
928 (forward-line 1)))
929 ;; after doing the deletions, add any padding that may be necessary.
930 (tar-pad-to-blocksize)
931 (narrow-to-region 1 tar-header-offset))
932 (set-buffer-multibyte multibyte)
933 (if (zerop n)
934 (message "Nothing to expunge.")
935 (message "%s files expunged. Be sure to save this buffer." n)))))
938 (defun tar-clear-modification-flags ()
939 "Remove the stars at the beginning of each line."
940 (interactive)
941 (save-excursion
942 (goto-char (point-min))
943 (while (< (position-bytes (point)) tar-header-offset)
944 (if (not (eq (following-char) ?\ ))
945 (progn (delete-char 1) (insert " ")))
946 (forward-line 1))))
949 (defun tar-chown-entry (new-uid)
950 "*Change the user-id associated with this entry in the tar file.
951 If this tar file was written by GNU tar, then you will be able to edit
952 the user id as a string; otherwise, you must edit it as a number.
953 You can force editing as a number by calling this with a prefix arg.
954 This does not modify the disk image; you must save the tar file itself
955 for this to be permanent."
956 (interactive (list
957 (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
958 (if (or current-prefix-arg
959 (not (tar-header-magic tokens)))
960 (let (n)
961 (while (not (numberp (setq n (read-minibuffer
962 "New UID number: "
963 (format "%s" (tar-header-uid tokens)))))))
965 (read-string "New UID string: " (tar-header-uname tokens))))))
966 (cond ((stringp new-uid)
967 (tar-setf (tar-header-uname (tar-desc-tokens (tar-current-descriptor)))
968 new-uid)
969 (tar-alter-one-field tar-uname-offset (concat new-uid "\000")))
971 (tar-setf (tar-header-uid (tar-desc-tokens (tar-current-descriptor)))
972 new-uid)
973 (tar-alter-one-field tar-uid-offset
974 (concat (substring (format "%6o" new-uid) 0 6) "\000 ")))))
977 (defun tar-chgrp-entry (new-gid)
978 "*Change the group-id associated with this entry in the tar file.
979 If this tar file was written by GNU tar, then you will be able to edit
980 the group id as a string; otherwise, you must edit it as a number.
981 You can force editing as a number by calling this with a prefix arg.
982 This does not modify the disk image; you must save the tar file itself
983 for this to be permanent."
984 (interactive (list
985 (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
986 (if (or current-prefix-arg
987 (not (tar-header-magic tokens)))
988 (let (n)
989 (while (not (numberp (setq n (read-minibuffer
990 "New GID number: "
991 (format "%s" (tar-header-gid tokens)))))))
993 (read-string "New GID string: " (tar-header-gname tokens))))))
994 (cond ((stringp new-gid)
995 (tar-setf (tar-header-gname (tar-desc-tokens (tar-current-descriptor)))
996 new-gid)
997 (tar-alter-one-field tar-gname-offset
998 (concat new-gid "\000")))
1000 (tar-setf (tar-header-gid (tar-desc-tokens (tar-current-descriptor)))
1001 new-gid)
1002 (tar-alter-one-field tar-gid-offset
1003 (concat (substring (format "%6o" new-gid) 0 6) "\000 ")))))
1005 (defun tar-rename-entry (new-name)
1006 "*Change the name associated with this entry in the tar file.
1007 This does not modify the disk image; you must save the tar file itself
1008 for this to be permanent."
1009 (interactive
1010 (list (read-string "New name: "
1011 (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
1012 (if (string= "" new-name) (error "zero length name"))
1013 (if (> (length new-name) 98) (error "name too long"))
1014 (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
1015 new-name)
1016 (tar-alter-one-field 0
1017 (substring (concat new-name (make-string 99 0)) 0 99)))
1020 (defun tar-chmod-entry (new-mode)
1021 "*Change the protection bits associated with this entry in the tar file.
1022 This does not modify the disk image; you must save the tar file itself
1023 for this to be permanent."
1024 (interactive (list (tar-parse-octal-integer-safe
1025 (read-string "New protection (octal): "))))
1026 (tar-setf (tar-header-mode (tar-desc-tokens (tar-current-descriptor)))
1027 new-mode)
1028 (tar-alter-one-field tar-mode-offset
1029 (concat (substring (format "%6o" new-mode) 0 6) "\000 ")))
1032 (defun tar-alter-one-field (data-position new-data-string)
1033 (let* ((descriptor (tar-current-descriptor))
1034 (tokens (tar-desc-tokens descriptor))
1035 (multibyte enable-multibyte-characters))
1036 (unwind-protect
1037 (save-excursion
1039 ;; update the header-line.
1040 (beginning-of-line)
1041 (let ((p (point)))
1042 (forward-line 1)
1043 (delete-region p (point))
1044 (insert (tar-header-block-summarize tokens) "\n")
1045 (setq tar-header-offset (position-bytes (point-max))))
1047 (widen)
1048 (set-buffer-multibyte nil)
1049 (let* ((start (+ (tar-desc-data-start descriptor) tar-header-offset -513)))
1051 ;; delete the old field and insert a new one.
1052 (goto-char (+ start data-position))
1053 (delete-region (point) (+ (point) (length new-data-string))) ; <--
1054 (insert new-data-string) ; <--
1056 ;; compute a new checksum and insert it.
1057 (let ((chk (tar-header-block-checksum
1058 (buffer-substring start (+ start 512)))))
1059 (goto-char (+ start tar-chk-offset))
1060 (delete-region (point) (+ (point) 8))
1061 (insert (format "%6o" chk))
1062 (insert 0)
1063 (insert ? )
1064 (tar-setf (tar-header-checksum tokens) chk)
1066 ;; ok, make sure we didn't botch it.
1067 (tar-header-block-check-checksum
1068 (buffer-substring start (+ start 512))
1069 chk (tar-header-name tokens))
1071 (narrow-to-region 1 tar-header-offset)
1072 (set-buffer-multibyte multibyte)
1073 (tar-next-line 0))))
1076 (defun tar-octal-time (timeval)
1077 ;; Format a timestamp as 11 octal digits. Ghod, I hope this works...
1078 (let ((hibits (car timeval)) (lobits (car (cdr timeval))))
1079 (insert (format "%05o%01o%05o"
1080 (lsh hibits -2)
1081 (logior (lsh (logand 3 hibits) 1) (> (logand lobits 32768) 0))
1082 (logand 32767 lobits)
1083 ))))
1085 (defun tar-subfile-save-buffer ()
1086 "In tar subfile mode, save this buffer into its parent tar-file buffer.
1087 This doesn't write anything to disk; you must save the parent tar-file buffer
1088 to make your changes permanent."
1089 (interactive)
1090 (if (not (and (boundp 'tar-superior-buffer) tar-superior-buffer))
1091 (error "This buffer has no superior tar file buffer"))
1092 (if (not (and (boundp 'tar-superior-descriptor) tar-superior-descriptor))
1093 (error "This buffer doesn't have an index into its superior tar file!"))
1094 (save-excursion
1095 (let ((subfile (current-buffer))
1096 (subfile-multibyte enable-multibyte-characters)
1097 (coding buffer-file-coding-system)
1098 (descriptor tar-superior-descriptor)
1099 subfile-size)
1100 ;; We must make the current buffer unibyte temporarily to avoid
1101 ;; multibyte->unibyte conversion in `insert-buffer'.
1102 (set-buffer-multibyte nil)
1103 (setq subfile-size (buffer-size))
1104 (set-buffer tar-superior-buffer)
1105 (let* ((tokens (tar-desc-tokens descriptor))
1106 (start (tar-desc-data-start descriptor))
1107 (name (tar-header-name tokens))
1108 (size (tar-header-size tokens))
1109 (size-pad (ash (ash (+ size 511) -9) 9))
1110 (head (memq descriptor tar-parse-info))
1111 (following-descs (cdr head))
1112 (tar-buffer-multibyte enable-multibyte-characters))
1113 (if (not head)
1114 (error "Can't find this tar file entry in its parent tar file!"))
1115 (unwind-protect
1116 (save-excursion
1117 (widen)
1118 (set-buffer-multibyte nil)
1119 ;; delete the old data...
1120 (let* ((data-start (+ start tar-header-offset -1))
1121 (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
1122 (delete-region data-start data-end)
1123 ;; insert the new data...
1124 (goto-char data-start)
1125 (insert-buffer subfile)
1126 (setq subfile-size
1127 (encode-coding-region
1128 data-start (+ data-start subfile-size) coding))
1130 ;; pad the new data out to a multiple of 512...
1131 (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
1132 (goto-char (+ data-start subfile-size))
1133 (insert (make-string (- subfile-size-pad subfile-size) 0))
1135 ;; update the data pointer of this and all following files...
1136 (tar-setf (tar-header-size tokens) subfile-size)
1137 (let ((difference (- subfile-size-pad size-pad)))
1138 (dolist (desc following-descs)
1139 (tar-setf (tar-desc-data-start desc)
1140 (+ (tar-desc-data-start desc) difference))))
1142 ;; Update the size field in the header block.
1143 (let ((header-start (- data-start 512)))
1144 (goto-char (+ header-start tar-size-offset))
1145 (delete-region (point) (+ (point) 12))
1146 (insert (format "%11o" subfile-size))
1147 (insert ? )
1149 ;; Maybe update the datestamp.
1150 (if (not tar-update-datestamp)
1152 (goto-char (+ header-start tar-time-offset))
1153 (delete-region (point) (+ (point) 12))
1154 (insert (tar-octal-time (current-time)))
1155 (insert ? ))
1157 ;; compute a new checksum and insert it.
1158 (let ((chk (tar-header-block-checksum
1159 (buffer-substring header-start data-start))))
1160 (goto-char (+ header-start tar-chk-offset))
1161 (delete-region (point) (+ (point) 8))
1162 (insert (format "%6o" chk))
1163 (insert 0)
1164 (insert ? )
1165 (tar-setf (tar-header-checksum tokens) chk)))
1167 ;; alter the descriptor-line...
1169 (let ((position (- (length tar-parse-info) (length head))))
1170 (goto-char (point-min))
1171 (next-line position)
1172 (beginning-of-line)
1173 (let ((p (point))
1174 after
1175 (m (set-marker (make-marker) tar-header-offset)))
1176 (forward-line 1)
1177 (setq after (point))
1178 ;; Insert the new text after the old, before deleting,
1179 ;; to preserve the window start.
1180 (let ((line (tar-header-block-summarize tokens t)))
1181 (if (multibyte-string-p line)
1182 (insert-before-markers (string-as-unibyte line) "\n")
1183 (insert-before-markers line "\n")))
1184 (delete-region p after)
1185 (setq tar-header-offset (marker-position m)))
1187 ;; after doing the insertion, add any final padding that may be necessary.
1188 (tar-pad-to-blocksize))
1189 (narrow-to-region 1 tar-header-offset)
1190 (set-buffer-multibyte tar-buffer-multibyte)))
1191 (set-buffer-modified-p t) ; mark the tar file as modified
1192 (tar-next-line 0)
1193 (set-buffer subfile)
1194 ;; Restore the buffer multibyteness.
1195 (set-buffer-multibyte subfile-multibyte)
1196 (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
1197 (message "Saved into tar-buffer `%s'. Be sure to save that buffer!"
1198 (buffer-name tar-superior-buffer))
1199 ;; Prevent basic-save-buffer from changing our coding-system.
1200 (setq last-coding-system-used buffer-file-coding-system)
1201 ;; Prevent ordinary saving from happening.
1202 t)))
1205 ;; When this function is called, it is sure that the buffer is unibyte.
1206 (defun tar-pad-to-blocksize ()
1207 "If we are being anal about tar file blocksizes, fix up the current buffer.
1208 Leaves the region wide."
1209 (if (null tar-anal-blocksize)
1211 (widen)
1212 (let* ((last-desc (nth (1- (length tar-parse-info)) tar-parse-info))
1213 (start (tar-desc-data-start last-desc))
1214 (tokens (tar-desc-tokens last-desc))
1215 (link-p (tar-header-link-type tokens))
1216 (size (if link-p 0 (tar-header-size tokens)))
1217 (data-end (+ start size))
1218 (bbytes (ash tar-anal-blocksize 9))
1219 (pad-to (+ bbytes (* bbytes (/ (1- data-end) bbytes))))
1220 (inhibit-read-only t) ; ##
1222 ;; If the padding after the last data is too long, delete some;
1223 ;; else insert some until we are padded out to the right number of blocks.
1225 (goto-char (+ (or tar-header-offset 0) data-end))
1226 (if (> (1+ (buffer-size)) (+ (or tar-header-offset 0) pad-to))
1227 (delete-region (+ (or tar-header-offset 0) pad-to) (1+ (buffer-size)))
1228 (insert (make-string (- (+ (or tar-header-offset 0) pad-to)
1229 (1+ (buffer-size)))
1230 0)))
1234 ;; Used in write-file-hook to write tar-files out correctly.
1235 (defun tar-mode-write-file ()
1236 (unwind-protect
1237 (save-excursion
1238 (widen)
1239 ;; Doing this here confuses things - the region gets left too wide!
1240 ;; I suppose this is run in a context where changing the buffer is bad.
1241 ;; (tar-pad-to-blocksize)
1242 ;; tar-header-offset turns out to be null for files fetched with W3,
1243 ;; at least.
1244 (let ((coding-system-for-write 'no-conversion))
1245 (write-region (or (byte-to-position tar-header-offset)
1246 (point-min))
1247 (point-max)
1248 buffer-file-name nil t))
1249 (tar-clear-modification-flags)
1250 (set-buffer-modified-p nil))
1251 (narrow-to-region 1 (byte-to-position tar-header-offset)))
1252 ;; Return t because we've written the file.
1255 (provide 'tar-mode)
1257 ;;; tar-mode.el ends here