1 ;;; tar-mode.el --- simple editing of tar files from GNU emacs
3 ;; Copyright (C) 1990,91,93,94,95,96,97,98,99,2000,01,2004
4 ;; Free Software Foundation, Inc.
6 ;; Author: Jamie Zawinski <jwz@lucid.com>
8 ;; Created: 04 Apr 1990
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software; you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation; either version 2, or (at your option)
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs; see the file COPYING. If not, write to the
25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26 ;; Boston, MA 02110-1301, USA.
30 ;; This package attempts to make dealing with Unix 'tar' archives easier.
31 ;; When this code is loaded, visiting a file whose name ends in '.tar' will
32 ;; cause the contents of that archive file to be displayed in a Dired-like
33 ;; listing. It is then possible to use the customary Dired keybindings to
34 ;; extract sub-files from that archive, either by reading them into their own
35 ;; editor buffers, or by copying them directly to arbitrary files on disk.
36 ;; It is also possible to delete sub-files from within the tar file and write
37 ;; the modified archive back to disk, or to edit sub-files within the archive
38 ;; and re-insert the modified files into the archive. See the documentation
39 ;; string of tar-mode for more info.
41 ;; This code now understands the extra fields that GNU tar adds to tar files.
43 ;; This interacts correctly with "uncompress.el" in the Emacs library,
46 ;; (autoload 'uncompress-while-visiting "uncompress")
47 ;; (setq auto-mode-alist (cons '("\\.Z$" . uncompress-while-visiting)
50 ;; Do not attempt to use tar-mode.el with crypt.el, you will lose.
52 ;; *************** TO DO ***************
54 ;; o chmod should understand "a+x,og-w".
56 ;; o It's not possible to add a NEW file to a tar archive; not that
57 ;; important, but still...
59 ;; o The code is less efficient that it could be - in a lot of places, I
60 ;; pull a 512-character string out of the buffer and parse it, when I could
61 ;; be parsing it in place, not garbaging a string. Should redo that.
63 ;; o I'd like a command that searches for a string/regexp in every subfile
64 ;; of an archive, where <esc> would leave you in a subfile-edit buffer.
65 ;; (Like the Meta-R command of the Zmacs mail reader.)
67 ;; o Sometimes (but not always) reverting the tar-file buffer does not
68 ;; re-grind the listing, and you are staring at the binary tar data.
69 ;; Typing 'g' again immediately after that will always revert and re-grind
70 ;; it, though. I have no idea why this happens.
72 ;; o Tar-mode interacts poorly with crypt.el and zcat.el because the tar
73 ;; write-file-hook actually writes the file. Instead it should remove the
74 ;; header (and conspire to put it back afterwards) so that other write-file
75 ;; hooks which frob the buffer have a chance to do their dirty work. There
76 ;; might be a problem if the tar write-file-hook does not come *first* on
79 ;; o Block files, sparse files, continuation files, and the various header
80 ;; types aren't editable. Actually I don't know that they work at all.
84 ;; Why does tar-mode edit the file itself instead of using tar?
86 ;; That means that you can edit tar files which you don't have room for
87 ;; on your local disk.
89 ;; I don't know about recent features in gnu tar, but old versions of tar
90 ;; can't replace a file in the middle of a tar file with a new version.
91 ;; Tar-mode can. I don't think tar can do things like chmod the subfiles.
92 ;; An implementation which involved unpacking and repacking the file into
93 ;; some scratch directory would be very wasteful, and wouldn't be able to
94 ;; preserve the file owners.
99 "Simple editing of tar files."
103 (defcustom tar-anal-blocksize
20
104 "*The blocksize of tar files written by Emacs, or nil, meaning don't care.
105 The blocksize of a tar file is not really the size of the blocks; rather, it is
106 the number of blocks written with one system call. When tarring to a tape,
107 this is the size of the *tape* blocks, but when writing to a file, it doesn't
108 matter much. The only noticeable difference is that if a tar file does not
109 have a blocksize of 20, tar will tell you that; all this really controls is
110 how many null padding bytes go on the end of the tar file."
111 :type
'(choice integer
(const nil
))
114 (defcustom tar-update-datestamp nil
115 "*Non-nil means Tar mode should play fast and loose with sub-file datestamps.
116 If this is true, then editing and saving a tar file entry back into its
117 tar file will update its datestamp. If false, the datestamp is unchanged.
118 You may or may not want this - it is good in that you can tell when a file
119 in a tar archive has been changed, but it is bad for the same reason that
120 editing a file in the tar archive at all is bad - the changed version of
121 the file never exists on disk."
125 (defcustom tar-mode-show-date nil
126 "*Non-nil means Tar mode should show the date/time of each subfile.
127 This information is useful, but it takes screen space away from file names."
131 (defvar tar-parse-info nil
)
132 ;; Be sure that this variable holds byte position, not char position.
133 (defvar tar-header-offset nil
)
134 (defvar tar-superior-buffer nil
)
135 (defvar tar-superior-descriptor nil
)
136 (defvar tar-subfile-mode nil
)
138 (put 'tar-parse-info
'permanent-local t
)
139 (put 'tar-header-offset
'permanent-local t
)
140 (put 'tar-superior-buffer
'permanent-local t
)
141 (put 'tar-superior-descriptor
'permanent-local t
)
143 (defmacro tar-setf
(form val
)
144 "A mind-numbingly simple implementation of setf."
145 (let ((mform (macroexpand form
(and (boundp 'byte-compile-macro-environment
)
146 byte-compile-macro-environment
))))
147 (cond ((symbolp mform
) (list 'setq mform val
))
148 ((not (consp mform
)) (error "can't setf %s" form
))
149 ((eq (car mform
) 'aref
)
150 (list 'aset
(nth 1 mform
) (nth 2 mform
) val
))
151 ((eq (car mform
) 'car
)
152 (list 'setcar
(nth 1 mform
) val
))
153 ((eq (car mform
) 'cdr
)
154 (list 'setcdr
(nth 1 mform
) val
))
155 (t (error "don't know how to setf %s" form
)))))
157 ;;; down to business.
159 (defmacro make-tar-header
(name mode uid git size date ck lt ln
160 magic uname gname devmaj devmin
)
161 (list 'vector name mode uid git size date ck lt ln
162 magic uname gname devmaj devmin
))
164 (defmacro tar-header-name
(x) (list 'aref x
0))
165 (defmacro tar-header-mode
(x) (list 'aref x
1))
166 (defmacro tar-header-uid
(x) (list 'aref x
2))
167 (defmacro tar-header-gid
(x) (list 'aref x
3))
168 (defmacro tar-header-size
(x) (list 'aref x
4))
169 (defmacro tar-header-date
(x) (list 'aref x
5))
170 (defmacro tar-header-checksum
(x) (list 'aref x
6))
171 (defmacro tar-header-link-type
(x) (list 'aref x
7))
172 (defmacro tar-header-link-name
(x) (list 'aref x
8))
173 (defmacro tar-header-magic
(x) (list 'aref x
9))
174 (defmacro tar-header-uname
(x) (list 'aref x
10))
175 (defmacro tar-header-gname
(x) (list 'aref x
11))
176 (defmacro tar-header-dmaj
(x) (list 'aref x
12))
177 (defmacro tar-header-dmin
(x) (list 'aref x
13))
179 (defmacro make-tar-desc
(data-start tokens
)
180 (list 'cons data-start tokens
))
182 (defmacro tar-desc-data-start
(x) (list 'car x
))
183 (defmacro tar-desc-tokens
(x) (list 'cdr x
))
185 (defconst tar-name-offset
0)
186 (defconst tar-mode-offset
(+ tar-name-offset
100))
187 (defconst tar-uid-offset
(+ tar-mode-offset
8))
188 (defconst tar-gid-offset
(+ tar-uid-offset
8))
189 (defconst tar-size-offset
(+ tar-gid-offset
8))
190 (defconst tar-time-offset
(+ tar-size-offset
12))
191 (defconst tar-chk-offset
(+ tar-time-offset
12))
192 (defconst tar-linkp-offset
(+ tar-chk-offset
8))
193 (defconst tar-link-offset
(+ tar-linkp-offset
1))
194 ;;; GNU-tar specific slots.
195 (defconst tar-magic-offset
(+ tar-link-offset
100))
196 (defconst tar-uname-offset
(+ tar-magic-offset
8))
197 (defconst tar-gname-offset
(+ tar-uname-offset
32))
198 (defconst tar-dmaj-offset
(+ tar-gname-offset
32))
199 (defconst tar-dmin-offset
(+ tar-dmaj-offset
8))
200 (defconst tar-end-offset
(+ tar-dmin-offset
8))
202 (defun tar-header-block-tokenize (string)
203 "Return a `tar-header' structure.
204 This is a list of name, mode, uid, gid, size,
205 write-date, checksum, link-type, and link-name."
206 (cond ((< (length string
) 512) nil
)
207 (;(some 'plusp string) ; <-- oops, massive cycle hog!
208 (or (not (= 0 (aref string
0))) ; This will do.
209 (not (= 0 (aref string
101))))
210 (let* ((name-end (1- tar-mode-offset
))
211 (link-end (1- tar-magic-offset
))
212 (uname-end (1- tar-gname-offset
))
213 (gname-end (1- tar-dmaj-offset
))
214 (link-p (aref string tar-linkp-offset
))
215 (magic-str (substring string tar-magic-offset
(1- tar-uname-offset
)))
216 (uname-valid-p (or (string= "ustar " magic-str
) (string= "GNUtar " magic-str
)))
218 (nulsexp "[^\000]*\000"))
219 (when (string-match nulsexp string tar-name-offset
)
220 (setq name-end
(min name-end
(1- (match-end 0)))))
221 (when (string-match nulsexp string tar-link-offset
)
222 (setq link-end
(min link-end
(1- (match-end 0)))))
223 (when (string-match nulsexp string tar-uname-offset
)
224 (setq uname-end
(min uname-end
(1- (match-end 0)))))
225 (when (string-match nulsexp string tar-gname-offset
)
226 (setq gname-end
(min gname-end
(1- (match-end 0)))))
227 (setq name
(substring string tar-name-offset name-end
)
228 link-p
(if (or (= link-p
0) (= link-p ?
0))
231 (setq linkname
(substring string tar-link-offset link-end
))
232 (if default-enable-multibyte-characters
234 (decode-coding-string name
(or file-name-coding-system
237 (decode-coding-string linkname
(or file-name-coding-system
239 (if (and (null link-p
) (string-match "/$" name
)) (setq link-p
5)) ; directory
242 (tar-parse-octal-integer string tar-mode-offset tar-uid-offset
)
243 (tar-parse-octal-integer string tar-uid-offset tar-gid-offset
)
244 (tar-parse-octal-integer string tar-gid-offset tar-size-offset
)
245 (tar-parse-octal-integer string tar-size-offset tar-time-offset
)
246 (tar-parse-octal-long-integer string tar-time-offset tar-chk-offset
)
247 (tar-parse-octal-integer string tar-chk-offset tar-linkp-offset
)
251 (and uname-valid-p
(substring string tar-uname-offset uname-end
))
252 (and uname-valid-p
(substring string tar-gname-offset gname-end
))
253 (tar-parse-octal-integer string tar-dmaj-offset tar-dmin-offset
)
254 (tar-parse-octal-integer string tar-dmin-offset tar-end-offset
)
256 (t 'empty-tar-block
)))
259 (defun tar-parse-octal-integer (string &optional start end
)
260 (if (null start
) (setq start
0))
261 (if (null end
) (setq end
(length string
)))
262 (if (= (aref string start
) 0)
266 (setq n
(if (< (aref string start
) ?
0) n
267 (+ (* n
8) (- (aref string start
) ?
0)))
271 (defun tar-parse-octal-long-integer (string &optional start end
)
272 (if (null start
) (setq start
0))
273 (if (null end
) (setq end
(length string
)))
274 (if (= (aref string start
) 0)
279 (if (>= (aref string start
) ?
0)
280 (setq lo
(+ (* lo
8) (- (aref string start
) ?
0))
281 hi
(+ (* hi
8) (ash lo -
16))
282 lo
(logand lo
65535)))
283 (setq start
(1+ start
)))
286 (defun tar-parse-octal-integer-safe (string)
287 (let ((L (length string
)))
288 (if (= L
0) (error "empty string"))
290 (if (or (< (aref string i
) ?
0)
291 (> (aref string i
) ?
7))
292 (error "`%c' is not an octal digit" (aref string i
)))))
293 (tar-parse-octal-integer string
))
296 (defun tar-header-block-checksum (string)
297 "Compute and return a tar-acceptable checksum for this block."
298 (let* ((chk-field-start tar-chk-offset
)
299 (chk-field-end (+ chk-field-start
8))
302 ;; Add up all of the characters except the ones in the checksum field.
303 ;; Add that field as if it were filled with spaces.
304 (while (< i chk-field-start
)
305 (setq sum
(+ sum
(aref string i
))
307 (setq i chk-field-end
)
309 (setq sum
(+ sum
(aref string i
))
313 (defun tar-header-block-check-checksum (hblock desired-checksum file-name
)
314 "Beep and print a warning if the checksum doesn't match."
315 (if (not (= desired-checksum
(tar-header-block-checksum hblock
)))
316 (progn (beep) (message "Invalid checksum for file %s!" file-name
))))
318 (defun tar-clip-time-string (time)
319 (let ((str (current-time-string time
)))
320 (concat " " (substring str
4 16) (substring str
19 24))))
322 (defun tar-grind-file-mode (mode)
323 "Construct a `-rw--r--r--' string indicating MODE.
324 MODE should be an integer which is a file mode value."
326 (if (zerop (logand 256 mode
)) ?- ?r
)
327 (if (zerop (logand 128 mode
)) ?- ?w
)
328 (if (zerop (logand 1024 mode
)) (if (zerop (logand 64 mode
)) ?- ?x
) ?s
)
329 (if (zerop (logand 32 mode
)) ?- ?r
)
330 (if (zerop (logand 16 mode
)) ?- ?w
)
331 (if (zerop (logand 2048 mode
)) (if (zerop (logand 8 mode
)) ?- ?x
) ?s
)
332 (if (zerop (logand 4 mode
)) ?- ?r
)
333 (if (zerop (logand 2 mode
)) ?- ?w
)
334 (if (zerop (logand 1 mode
)) ?- ?x
)))
336 (defun tar-header-block-summarize (tar-hblock &optional mod-p
)
337 "Return a line similar to the output of `tar -vtf'."
338 (let ((name (tar-header-name tar-hblock
))
339 (mode (tar-header-mode tar-hblock
))
340 (uid (tar-header-uid tar-hblock
))
341 (gid (tar-header-gid tar-hblock
))
342 (uname (tar-header-uname tar-hblock
))
343 (gname (tar-header-gname tar-hblock
))
344 (size (tar-header-size tar-hblock
))
345 (time (tar-header-date tar-hblock
))
346 (ck (tar-header-checksum tar-hblock
))
347 (type (tar-header-link-type tar-hblock
))
348 (link-name (tar-header-link-name tar-hblock
)))
349 (format "%c%c%s%8s/%-8s%7s%s %s%s"
351 (cond ((or (eq type nil
) (eq type
0)) ?-
)
352 ((eq type
1) ?h
) ; link
353 ((eq type
2) ?l
) ; symlink
354 ((eq type
3) ?c
) ; char special
355 ((eq type
4) ?b
) ; block special
356 ((eq type
5) ?d
) ; directory
357 ((eq type
6) ?p
) ; FIFO/pipe
358 ((eq type
20) ?
*) ; directory listing
359 ((eq type
28) ?L
) ; next has longname
360 ((eq type
29) ?M
) ; multivolume continuation
361 ((eq type
35) ?S
) ; sparse
362 ((eq type
38) ?V
) ; volume header
365 (tar-grind-file-mode mode
)
366 (if (= 0 (length uname
)) uid uname
)
367 (if (= 0 (length gname
)) gid gname
)
369 (if tar-mode-show-date
(tar-clip-time-string time
) "")
371 'mouse-face
'highlight
372 'help-echo
"mouse-2: extract this file into a buffer")
373 (if (or (eq type
1) (eq type
2))
374 (concat (if (= type
1) " ==> " " --> ") link-name
)
377 (defun tar-untar-buffer ()
378 "Extract all archive members in the tar-file into the current directory."
380 (let ((multibyte enable-multibyte-characters
))
384 (set-buffer-multibyte nil
)
385 (dolist (descriptor tar-parse-info
)
386 (let* ((tokens (tar-desc-tokens descriptor
))
387 (name (tar-header-name tokens
))
388 (dir (file-name-directory name
))
389 (start (+ (tar-desc-data-start descriptor
)
390 (- tar-header-offset
(point-min))))
391 (end (+ start
(tar-header-size tokens
))))
392 (unless (file-directory-p name
)
393 (message "Extracting %s" name
)
394 (if (and dir
(not (file-exists-p dir
)))
395 (make-directory dir t
))
396 (unless (file-directory-p name
)
397 (write-region start end name
))
398 (set-file-modes name
(tar-header-mode tokens
))))))
399 (set-buffer-multibyte multibyte
))))
401 (defun tar-summarize-buffer ()
402 "Parse the contents of the tar file in the current buffer.
403 Place a dired-like listing on the front;
404 then narrow to it, so that only that listing
405 is visible (and the real data of the buffer is hidden)."
406 (set-buffer-multibyte nil
)
410 (make-progress-reporter "Parsing tar file..."
411 (point-min) (max 1 (- (buffer-size) 1024))))
413 (while (and (<= (+ pos
512) (point-max))
414 (not (eq 'empty-tar-block
416 (tar-header-block-tokenize
417 (buffer-substring pos
(+ pos
512)))))))
418 (setq pos
(+ pos
512))
419 (progress-reporter-update progress-reporter pos
)
420 (if (eq (tar-header-link-type tokens
) 20)
421 ;; Foo. There's an extra empty block after these.
422 (setq pos
(+ pos
512)))
423 (let ((size (tar-header-size tokens
)))
425 (error "%s has size %s - corrupted"
426 (tar-header-name tokens
) size
))
428 ; This is just too slow. Don't really need it anyway....
429 ;(tar-header-block-check-checksum
430 ; hblock (tar-header-block-checksum hblock)
431 ; (tar-header-name tokens))
433 (setq result
(cons (make-tar-desc pos tokens
) result
))
435 (and (null (tar-header-link-type tokens
))
438 (+ pos
512 (ash (ash (1- size
) -
9) 9)) ; this works
439 ;(+ pos (+ size (- 512 (rem (1- size) 512)))) ; this doesn't
441 (make-local-variable 'tar-parse-info
)
442 (setq tar-parse-info
(nreverse result
))
443 ;; A tar file should end with a block or two of nulls,
444 ;; but let's not get a fatal error if it doesn't.
445 (if (eq tokens
'empty-tar-block
)
446 (progress-reporter-done progress-reporter
)
447 (message "Warning: premature EOF parsing tar file")))
449 (goto-char (point-min))
450 (let ((buffer-read-only nil
)
452 ;; Collect summary lines and insert them all at once since tar files
453 ;; can be pretty big.
454 (dolist (tar-desc (reverse tar-parse-info
))
456 (cons (tar-header-block-summarize (tar-desc-tokens tar-desc
))
459 (let ((total-summaries (apply 'concat summaries
)))
460 (if (multibyte-string-p total-summaries
)
461 (set-buffer-multibyte t
))
462 (insert total-summaries
))
463 (make-local-variable 'tar-header-offset
)
464 (setq tar-header-offset
(point))
465 (narrow-to-region (point-min) tar-header-offset
)
466 (if enable-multibyte-characters
467 (setq tar-header-offset
(position-bytes tar-header-offset
)))
468 (set-buffer-modified-p nil
))))
470 (defvar tar-mode-map nil
"*Local keymap for Tar mode listings.")
474 (setq tar-mode-map
(make-keymap))
475 (suppress-keymap tar-mode-map
)
476 (define-key tar-mode-map
" " 'tar-next-line
)
477 (define-key tar-mode-map
"C" 'tar-copy
)
478 (define-key tar-mode-map
"d" 'tar-flag-deleted
)
479 (define-key tar-mode-map
"\^D" 'tar-flag-deleted
)
480 (define-key tar-mode-map
"e" 'tar-extract
)
481 (define-key tar-mode-map
"f" 'tar-extract
)
482 (define-key tar-mode-map
"\C-m" 'tar-extract
)
483 (define-key tar-mode-map
[mouse-2
] 'tar-mouse-extract
)
484 (define-key tar-mode-map
"g" 'revert-buffer
)
485 (define-key tar-mode-map
"h" 'describe-mode
)
486 (define-key tar-mode-map
"n" 'tar-next-line
)
487 (define-key tar-mode-map
"\^N" 'tar-next-line
)
488 (define-key tar-mode-map
[down] 'tar-next-line)
489 (define-key tar-mode-map "o" 'tar-extract-other-window)
490 (define-key tar-mode-map "p" 'tar-previous-line)
491 (define-key tar-mode-map "q" 'quit-window)
492 (define-key tar-mode-map "\^P" 'tar-previous-line)
493 (define-key tar-mode-map [up] 'tar-previous-line)
494 (define-key tar-mode-map "R" 'tar-rename-entry)
495 (define-key tar-mode-map "u" 'tar-unflag)
496 (define-key tar-mode-map "v" 'tar-view)
497 (define-key tar-mode-map "x" 'tar-expunge)
498 (define-key tar-mode-map "\177" 'tar-unflag-backwards)
499 (define-key tar-mode-map "E" 'tar-extract-other-window)
500 (define-key tar-mode-map "M" 'tar-chmod-entry)
501 (define-key tar-mode-map "G" 'tar-chgrp-entry)
502 (define-key tar-mode-map "O" 'tar-chown-entry)
505 ;; Make menu bar items.
507 ;; Get rid of the Edit menu bar item to save space.
508 (define-key tar-mode-map [menu-bar edit] 'undefined)
510 (define-key tar-mode-map [menu-bar immediate]
511 (cons "Immediate" (make-sparse-keymap "Immediate")))
513 (define-key tar-mode-map [menu-bar immediate view]
514 '("View This File" . tar-view))
515 (define-key tar-mode-map [menu-bar immediate display]
516 '("Display in Other Window" . tar-display-other-window))
517 (define-key tar-mode-map [menu-bar immediate find-file-other-window]
518 '("Find in Other Window" . tar-extract-other-window))
519 (define-key tar-mode-map [menu-bar immediate find-file]
520 '("Find This File" . tar-extract))
522 (define-key tar-mode-map [menu-bar mark]
523 (cons "Mark" (make-sparse-keymap "Mark")))
525 (define-key tar-mode-map [menu-bar mark unmark-all]
526 '("Unmark All" . tar-clear-modification-flags))
527 (define-key tar-mode-map [menu-bar mark deletion]
528 '("Flag" . tar-flag-deleted))
529 (define-key tar-mode-map [menu-bar mark unmark]
530 '("Unflag" . tar-unflag))
532 (define-key tar-mode-map [menu-bar operate]
533 (cons "Operate" (make-sparse-keymap "Operate")))
535 (define-key tar-mode-map [menu-bar operate chown]
536 '("Change Owner..." . tar-chown-entry))
537 (define-key tar-mode-map [menu-bar operate chgrp]
538 '("Change Group..." . tar-chgrp-entry))
539 (define-key tar-mode-map [menu-bar operate chmod]
540 '("Change Mode..." . tar-chmod-entry))
541 (define-key tar-mode-map [menu-bar operate rename]
542 '("Rename to..." . tar-rename-entry))
543 (define-key tar-mode-map [menu-bar operate copy]
544 '("Copy to..." . tar-copy))
545 (define-key tar-mode-map [menu-bar operate expunge]
546 '("Expunge Marked Files" . tar-expunge))
548 ;; tar mode is suitable only for specially formatted data.
549 (put 'tar-mode 'mode-class 'special)
550 (put 'tar-subfile-mode 'mode-class 'special)
553 (define-derived-mode tar-mode nil "Tar"
554 "Major mode for viewing a tar file as a dired-like listing of its contents.
555 You can move around using the usual cursor motion commands.
556 Letters no longer insert themselves.
557 Type `e' to pull a file out of the tar file and into its own buffer;
558 or click mouse-2 on the file's line in the Tar mode buffer.
559 Type `c' to copy an entry from the tar file into another file on disk.
561 If you edit a sub-file of this archive (as with the `e' command) and
562 save it with Control-x Control-s, the contents of that buffer will be
563 saved back into the tar-file buffer; in this way you can edit a file
564 inside of a tar archive without extracting it and re-archiving it.
566 See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
568 ;; this is not interactive because you shouldn't be turning this
569 ;; mode on and off. You can corrupt things that way.
570 ;; rms: with permanent locals, it should now be possible to make this work
571 ;; interactively in some reasonable fashion.
572 (make-local-variable 'tar-header-offset)
573 (make-local-variable 'tar-parse-info)
574 (set (make-local-variable 'require-final-newline) nil) ; binary data, dude...
575 (set (make-local-variable 'revert-buffer-function) 'tar-mode-revert)
576 (set (make-local-variable 'local-enable-local-variables) nil)
577 (set (make-local-variable 'next-line-add-newlines) nil)
578 ;; Prevent loss of data when saving the file.
579 (set (make-local-variable 'file-precious-flag) t)
581 (set (make-local-variable 'write-contents-functions) '(tar-mode-write-file))
582 (buffer-disable-undo)
584 (if (and (boundp 'tar-header-offset) tar-header-offset)
585 (narrow-to-region (point-min) (byte-to-position tar-header-offset))
586 (tar-summarize-buffer)
590 (defun tar-subfile-mode (p)
591 "Minor mode for editing an element of a tar-file.
592 This mode arranges for \"saving\" this buffer to write the data
593 into the tar-file buffer that it came from. The changes will actually
594 appear on disk when you save the tar-file's buffer."
596 (or (and (boundp 'tar-superior-buffer) tar-superior-buffer)
597 (error "This buffer is not an element of a tar file"))
598 ;; Don't do this, because it is redundant and wastes mode line space.
599 ;; (or (assq 'tar-subfile-mode minor-mode-alist)
600 ;; (setq minor-mode-alist (append minor-mode-alist
601 ;; (list '(tar-subfile-mode " TarFile")))))
602 (make-local-variable 'tar-subfile-mode)
603 (setq tar-subfile-mode
605 (not tar-subfile-mode)
606 (> (prefix-numeric-value p) 0)))
607 (cond (tar-subfile-mode
608 (add-hook 'write-file-functions 'tar-subfile-save-buffer nil t)
609 ;; turn off auto-save.
611 (setq buffer-auto-save-file-name nil)
612 (run-hooks 'tar-subfile-mode-hook))
614 (remove-hook 'write-file-functions 'tar-subfile-save-buffer t))))
617 ;; Revert the buffer and recompute the dired-like listing.
618 (defun tar-mode-revert (&optional no-auto-save no-confirm)
619 (let ((revert-buffer-function nil)
620 (old-offset tar-header-offset)
622 (setq tar-header-offset nil)
624 (and (revert-buffer t no-confirm)
628 ;; If the revert was canceled,
629 ;; put back the old value of tar-header-offset.
631 (setq tar-header-offset old-offset)))))
634 (defun tar-next-line (arg)
635 "Move cursor vertically down ARG lines and to the start of the filename."
638 (if (eobp) nil (forward-char (if tar-mode-show-date 54 36))))
640 (defun tar-previous-line (arg)
641 "Move cursor vertically up ARG lines and to the start of the filename."
643 (tar-next-line (- arg)))
645 (defun tar-current-descriptor (&optional noerror)
646 "Return the tar-descriptor of the current line, or signals an error."
647 ;; I wish lines had plists, like in ZMACS...
648 (or (nth (count-lines (point-min)
649 (save-excursion (beginning-of-line) (point)))
653 (error "This line does not describe a tar-file entry"))))
655 (defun tar-get-descriptor ()
656 (let* ((descriptor (tar-current-descriptor))
657 (tokens (tar-desc-tokens descriptor))
658 (size (tar-header-size tokens))
659 (link-p (tar-header-link-type tokens)))
661 (error "This is a %s, not a real file"
662 (cond ((eq link-p 5) "directory")
663 ((eq link-p 20) "tar directory header")
664 ((eq link-p 28) "next has longname")
665 ((eq link-p 29) "multivolume-continuation")
666 ((eq link-p 35) "sparse entry")
667 ((eq link-p 38) "volume header")
669 (if (zerop size) (error "This is a zero-length file"))
672 (defun tar-mouse-extract (event)
673 "Extract a file whose tar directory line you click on."
676 (set-buffer (window-buffer (posn-window (event-end event))))
678 (goto-char (posn-point (event-end event)))
679 ;; Just make sure this doesn't get an error.
680 (tar-get-descriptor)))
681 (select-window (posn-window (event-end event)))
682 (goto-char (posn-point (event-end event)))
685 (defun tar-extract (&optional other-window-p)
686 "In Tar mode, extract this entry of the tar file into its own buffer."
688 (let* ((view-p (eq other-window-p 'view))
689 (descriptor (tar-get-descriptor))
690 (tokens (tar-desc-tokens descriptor))
691 (name (tar-header-name tokens))
692 (size (tar-header-size tokens))
693 (start (+ (tar-desc-data-start descriptor)
694 (- tar-header-offset (point-min))))
695 (end (+ start size)))
696 (let* ((tar-buffer (current-buffer))
697 (tar-buffer-multibyte enable-multibyte-characters)
698 (tarname (buffer-name))
699 (bufname (concat (file-name-nondirectory name)
703 (read-only-p (or buffer-read-only view-p))
704 (new-buffer-file-name (expand-file-name
705 ;; `:' is not allowed on Windows
706 (concat tarname "!" name)))
707 (buffer (get-file-buffer new-buffer-file-name))
710 (setq buffer (generate-new-buffer bufname))
711 (setq bufname (buffer-name buffer))
712 (setq just-created t)
716 (set-buffer-multibyte nil)
719 (let ((buffer-undo-list t))
720 (if enable-multibyte-characters
722 ;; We must avoid unibyte->multibyte conversion.
723 (set-buffer-multibyte nil)
724 (insert-buffer-substring tar-buffer start end)
725 (set-buffer-multibyte t))
726 (insert-buffer-substring tar-buffer start end))
727 (goto-char (point-min))
728 (setq buffer-file-name new-buffer-file-name)
729 (setq buffer-file-truename
730 (abbreviate-file-name buffer-file-name))
731 ;; We need to mimic the parts of insert-file-contents
732 ;; which determine the coding-system and decode the text.
734 (or coding-system-for-read
735 (and set-auto-coding-function
737 (funcall set-auto-coding-function
738 name (- (point-max) (point)))))))
739 (multibyte enable-multibyte-characters)
740 (detected (detect-coding-region
742 (min (+ (point-min) 16384) (point-max)) t)))
744 (or (numberp (coding-system-eol-type coding))
745 (vectorp (coding-system-eol-type detected))
746 (setq coding (coding-system-change-eol-conversion
748 (coding-system-eol-type detected))))
750 (or (find-new-buffer-file-coding-system detected)
752 (find-operation-coding-system
753 'insert-file-contents buffer-file-name)))
754 (if (consp file-coding)
755 (setq file-coding (car file-coding))
757 (if (or (eq coding 'no-conversion)
758 (eq (coding-system-type coding) 5))
759 (setq multibyte (set-buffer-multibyte nil)))
762 (coding-system-change-text-conversion
764 (decode-coding-region (point-min) (point-max) coding)
765 (set-buffer-file-coding-system coding))
766 ;; Set the default-directory to the dir of the
768 (setq default-directory
770 (set-buffer tar-buffer)
772 (normal-mode) ; pick a mode.
773 (rename-buffer bufname)
774 (make-local-variable 'tar-superior-buffer)
775 (make-local-variable 'tar-superior-descriptor)
776 (setq tar-superior-buffer tar-buffer)
777 (setq tar-superior-descriptor descriptor)
778 (setq buffer-read-only read-only-p)
779 (set-buffer-modified-p nil))
780 (tar-subfile-mode 1))
781 (set-buffer tar-buffer))
782 (narrow-to-region (point-min) tar-header-offset)
783 (set-buffer-multibyte tar-buffer-multibyte)))
785 (view-buffer buffer (and just-created 'kill-buffer))
786 (if (eq other-window-p 'display)
787 (display-buffer buffer)
789 (switch-to-buffer-other-window buffer)
790 (switch-to-buffer buffer)))))))
793 (defun tar-extract-other-window ()
794 "*In Tar mode, find this entry of the tar file in another window."
798 (defun tar-display-other-window ()
799 "*In Tar mode, display this entry of the tar file in another window."
801 (tar-extract 'display))
804 "*In Tar mode, view the tar file entry on this line."
809 (defun tar-read-file-name (&optional prompt)
810 "Read a file name with this line's entry as the default."
811 (or prompt (setq prompt "Copy to: "))
812 (let* ((default-file (expand-file-name
813 (tar-header-name (tar-desc-tokens
814 (tar-current-descriptor)))))
815 (target (expand-file-name
816 (read-file-name prompt
817 (file-name-directory default-file)
819 (if (or (string= "" (file-name-nondirectory target))
820 (file-directory-p target))
821 (setq target (concat (if (string-match "/$" target)
822 (substring target 0 (1- (match-end 0)))
825 (file-name-nondirectory default-file))))
829 (defun tar-copy (&optional to-file)
830 "*In Tar mode, extract this entry of the tar file into a file on disk.
831 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
832 the current tar-entry."
833 (interactive (list (tar-read-file-name)))
834 (let* ((descriptor (tar-get-descriptor))
835 (tokens (tar-desc-tokens descriptor))
836 (name (tar-header-name tokens))
837 (size (tar-header-size tokens))
838 (start (+ (tar-desc-data-start descriptor)
839 (- tar-header-offset (point-min))))
841 (multibyte enable-multibyte-characters)
842 (inhibit-file-name-handlers inhibit-file-name-handlers)
843 (inhibit-file-name-operation inhibit-file-name-operation))
846 ;; Inhibit compressing a subfile again if *both* name and
847 ;; to-file are handled by jka-compr
848 (if (and (eq (find-file-name-handler name 'write-region) 'jka-compr-handler)
849 (eq (find-file-name-handler to-file 'write-region) 'jka-compr-handler))
850 (setq inhibit-file-name-handlers
851 (cons 'jka-compr-handler
852 (and (eq inhibit-file-name-operation 'write-region)
853 inhibit-file-name-handlers))
854 inhibit-file-name-operation 'write-region))
856 (let ((coding-system-for-write 'no-conversion))
857 (set-buffer-multibyte nil)
858 (write-region start end to-file nil nil nil t))
859 (set-buffer-multibyte multibyte)))
860 (message "Copied tar entry %s to %s" name to-file)))
862 (defun tar-flag-deleted (p &optional unflag)
863 "*In Tar mode, mark this sub-file to be deleted from the tar file.
864 With a prefix argument, mark that many files."
867 (dotimes (i (if (< p 0) (- p) p))
868 (if (tar-current-descriptor unflag) ; barf if we're not on an entry-line.
871 (insert (if unflag " " "D"))))
872 (forward-line (if (< p 0) -1 1)))
873 (if (eobp) nil (forward-char 36)))
875 (defun tar-unflag (p)
876 "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
877 With a prefix argument, un-mark that many files forward."
879 (tar-flag-deleted p t))
881 (defun tar-unflag-backwards (p)
882 "*In Tar mode, un-mark this sub-file if it is marked to be deleted.
883 With a prefix argument, un-mark that many files backward."
885 (tar-flag-deleted (- p) t))
888 ;; When this function is called, it is sure that the buffer is unibyte.
889 (defun tar-expunge-internal ()
890 "Expunge the tar-entry specified by the current line."
891 (let* ((descriptor (tar-current-descriptor))
892 (tokens (tar-desc-tokens descriptor))
893 (line (tar-desc-data-start descriptor))
894 (name (tar-header-name tokens))
895 (size (tar-header-size tokens))
896 (link-p (tar-header-link-type tokens))
897 (start (tar-desc-data-start descriptor))
898 (following-descs (cdr (memq descriptor tar-parse-info))))
899 (if link-p (setq size 0)) ; size lies for hard-links.
901 ;; delete the current line...
903 (let ((line-start (point)))
904 (end-of-line) (forward-char)
905 (let ((line-len (- (point) line-start)))
906 (delete-region line-start (point))
908 ;; decrement the header-pointer to be in sync...
909 (setq tar-header-offset (- tar-header-offset line-len))))
911 ;; delete the data pointer...
912 (setq tar-parse-info (delq descriptor tar-parse-info))
914 ;; delete the data from inside the file...
916 (let* ((data-start (+ start tar-header-offset -513))
917 (data-end (+ data-start 512 (ash (ash (+ size 511) -9) 9))))
918 (delete-region data-start data-end)
920 ;; and finally, decrement the start-pointers of all following
921 ;; entries in the archive. This is a pig when deleting a bunch
922 ;; of files at once - we could optimize this to only do the
923 ;; iteration over the files that remain, or only iterate up to
924 ;; the next file to be deleted.
925 (let ((data-length (- data-end data-start)))
926 (dolist (desc following-descs)
927 (tar-setf (tar-desc-data-start desc)
928 (- (tar-desc-data-start desc) data-length))))
930 (narrow-to-region (point-min) tar-header-offset))
933 (defun tar-expunge (&optional noconfirm)
934 "*In Tar mode, delete all the archived files flagged for deletion.
935 This does not modify the disk image; you must save the tar file itself
936 for this to be permanent."
939 (y-or-n-p "Expunge files marked for deletion? "))
941 (multibyte enable-multibyte-characters))
942 (set-buffer-multibyte nil)
944 (goto-char (point-min))
947 (progn (tar-expunge-internal)
950 ;; after doing the deletions, add any padding that may be necessary.
951 (tar-pad-to-blocksize)
952 (narrow-to-region (point-min) tar-header-offset))
953 (set-buffer-multibyte multibyte)
955 (message "Nothing to expunge.")
956 (message "%s files expunged. Be sure to save this buffer." n)))))
959 (defun tar-clear-modification-flags ()
960 "Remove the stars at the beginning of each line."
963 (goto-char (point-min))
964 (while (< (position-bytes (point)) tar-header-offset)
965 (if (not (eq (following-char) ?\ ))
966 (progn (delete-char 1) (insert " ")))
970 (defun tar-chown-entry (new-uid)
971 "*Change the user-id associated with this entry in the tar file.
972 If this tar file was written by GNU tar, then you will be able to edit
973 the user id as a string; otherwise, you must edit it as a number.
974 You can force editing as a number by calling this with a prefix arg.
975 This does not modify the disk image; you must save the tar file itself
976 for this to be permanent."
978 (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
979 (if (or current-prefix-arg
980 (not (tar-header-magic tokens)))
982 (while (not (numberp (setq n (read-minibuffer
984 (format "%s" (tar-header-uid tokens)))))))
986 (read-string "New UID string: " (tar-header-uname tokens))))))
987 (cond ((stringp new-uid)
988 (tar-setf (tar-header-uname (tar-desc-tokens (tar-current-descriptor)))
990 (tar-alter-one-field tar-uname-offset (concat new-uid "\000")))
992 (tar-setf (tar-header-uid (tar-desc-tokens (tar-current-descriptor)))
994 (tar-alter-one-field tar-uid-offset
995 (concat (substring (format "%6o" new-uid) 0 6) "\000 ")))))
998 (defun tar-chgrp-entry (new-gid)
999 "*Change the group-id associated with this entry in the tar file.
1000 If this tar file was written by GNU tar, then you will be able to edit
1001 the group id as a string; otherwise, you must edit it as a number.
1002 You can force editing as a number by calling this with a prefix arg.
1003 This does not modify the disk image; you must save the tar file itself
1004 for this to be permanent."
1006 (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
1007 (if (or current-prefix-arg
1008 (not (tar-header-magic tokens)))
1010 (while (not (numberp (setq n (read-minibuffer
1012 (format "%s" (tar-header-gid tokens)))))))
1014 (read-string "New GID string: " (tar-header-gname tokens))))))
1015 (cond ((stringp new-gid)
1016 (tar-setf (tar-header-gname (tar-desc-tokens (tar-current-descriptor)))
1018 (tar-alter-one-field tar-gname-offset
1019 (concat new-gid "\000")))
1021 (tar-setf (tar-header-gid (tar-desc-tokens (tar-current-descriptor)))
1023 (tar-alter-one-field tar-gid-offset
1024 (concat (substring (format "%6o" new-gid) 0 6) "\000 ")))))
1026 (defun tar-rename-entry (new-name)
1027 "*Change the name associated with this entry in the tar file.
1028 This does not modify the disk image; you must save the tar file itself
1029 for this to be permanent."
1031 (list (read-string "New name: "
1032 (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
1033 (if (string= "" new-name) (error "zero length name"))
1034 (if (> (length new-name) 98) (error "name too long"))
1035 (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
1037 (tar-alter-one-field 0
1038 (substring (concat new-name (make-string 99 0)) 0 99)))
1041 (defun tar-chmod-entry (new-mode)
1042 "*Change the protection bits associated with this entry in the tar file.
1043 This does not modify the disk image; you must save the tar file itself
1044 for this to be permanent."
1045 (interactive (list (tar-parse-octal-integer-safe
1046 (read-string "New protection (octal): "))))
1047 (tar-setf (tar-header-mode (tar-desc-tokens (tar-current-descriptor)))
1049 (tar-alter-one-field tar-mode-offset
1050 (concat (substring (format "%6o" new-mode) 0 6) "\000 ")))
1053 (defun tar-alter-one-field (data-position new-data-string)
1054 (let* ((descriptor (tar-current-descriptor))
1055 (tokens (tar-desc-tokens descriptor))
1056 (multibyte enable-multibyte-characters))
1060 ;; update the header-line.
1064 (delete-region p (point))
1065 (insert (tar-header-block-summarize tokens) "\n")
1066 (setq tar-header-offset (position-bytes (point-max))))
1069 (set-buffer-multibyte nil)
1070 (let* ((start (+ (tar-desc-data-start descriptor) tar-header-offset -513)))
1072 ;; delete the old field and insert a new one.
1073 (goto-char (+ start data-position))
1074 (delete-region (point) (+ (point) (length new-data-string))) ; <--
1075 (insert new-data-string) ; <--
1077 ;; compute a new checksum and insert it.
1078 (let ((chk (tar-header-block-checksum
1079 (buffer-substring start (+ start 512)))))
1080 (goto-char (+ start tar-chk-offset))
1081 (delete-region (point) (+ (point) 8))
1082 (insert (format "%6o" chk))
1085 (tar-setf (tar-header-checksum tokens) chk)
1087 ;; ok, make sure we didn't botch it.
1088 (tar-header-block-check-checksum
1089 (buffer-substring start (+ start 512))
1090 chk (tar-header-name tokens))
1092 (narrow-to-region (point-min) tar-header-offset)
1093 (set-buffer-multibyte multibyte)
1094 (tar-next-line 0))))
1097 (defun tar-octal-time (timeval)
1098 ;; Format a timestamp as 11 octal digits. Ghod, I hope this works...
1099 (let ((hibits (car timeval)) (lobits (car (cdr timeval))))
1100 (format "%05o%01o%05o"
1102 (logior (lsh (logand 3 hibits) 1)
1103 (if (> (logand lobits 32768) 0) 1 0))
1104 (logand 32767 lobits)
1107 (defun tar-subfile-save-buffer ()
1108 "In tar subfile mode, save this buffer into its parent tar-file buffer.
1109 This doesn't write anything to disk; you must save the parent tar-file buffer
1110 to make your changes permanent."
1112 (if (not (and (boundp 'tar-superior-buffer) tar-superior-buffer))
1113 (error "This buffer has no superior tar file buffer"))
1114 (if (not (and (boundp 'tar-superior-descriptor) tar-superior-descriptor))
1115 (error "This buffer doesn't have an index into its superior tar file!"))
1117 (let ((subfile (current-buffer))
1118 (subfile-multibyte enable-multibyte-characters)
1119 (coding buffer-file-coding-system)
1120 (descriptor tar-superior-descriptor)
1122 ;; We must make the current buffer unibyte temporarily to avoid
1123 ;; multibyte->unibyte conversion in `insert-buffer'.
1124 (set-buffer-multibyte nil)
1125 (setq subfile-size (buffer-size))
1126 (set-buffer tar-superior-buffer)
1127 (let* ((tokens (tar-desc-tokens descriptor))
1128 (start (tar-desc-data-start descriptor))
1129 (name (tar-header-name tokens))
1130 (size (tar-header-size tokens))
1131 (size-pad (ash (ash (+ size 511) -9) 9))
1132 (head (memq descriptor tar-parse-info))
1133 (following-descs (cdr head))
1134 (tar-buffer-multibyte enable-multibyte-characters))
1136 (error "Can't find this tar file entry in its parent tar file!"))
1140 (set-buffer-multibyte nil)
1141 ;; delete the old data...
1142 (let* ((data-start (+ start (- tar-header-offset (point-min))))
1143 (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
1144 (delete-region data-start data-end)
1145 ;; insert the new data...
1146 (goto-char data-start)
1147 (insert-buffer subfile)
1149 (encode-coding-region
1150 data-start (+ data-start subfile-size) coding))
1152 ;; pad the new data out to a multiple of 512...
1153 (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
1154 (goto-char (+ data-start subfile-size))
1155 (insert (make-string (- subfile-size-pad subfile-size) 0))
1157 ;; update the data pointer of this and all following files...
1158 (tar-setf (tar-header-size tokens) subfile-size)
1159 (let ((difference (- subfile-size-pad size-pad)))
1160 (dolist (desc following-descs)
1161 (tar-setf (tar-desc-data-start desc)
1162 (+ (tar-desc-data-start desc) difference))))
1164 ;; Update the size field in the header block.
1165 (let ((header-start (- data-start 512)))
1166 (goto-char (+ header-start tar-size-offset))
1167 (delete-region (point) (+ (point) 12))
1168 (insert (format "%11o" subfile-size))
1171 ;; Maybe update the datestamp.
1172 (if (not tar-update-datestamp)
1174 (goto-char (+ header-start tar-time-offset))
1175 (delete-region (point) (+ (point) 12))
1176 (insert (tar-octal-time (current-time)))
1179 ;; compute a new checksum and insert it.
1180 (let ((chk (tar-header-block-checksum
1181 (buffer-substring header-start data-start))))
1182 (goto-char (+ header-start tar-chk-offset))
1183 (delete-region (point) (+ (point) 8))
1184 (insert (format "%6o" chk))
1187 (tar-setf (tar-header-checksum tokens) chk)))
1189 ;; alter the descriptor-line...
1191 (let ((position (- (length tar-parse-info) (length head))))
1192 (goto-char (point-min))
1193 (next-line position)
1197 (m (set-marker (make-marker) tar-header-offset)))
1199 (setq after (point))
1200 ;; Insert the new text after the old, before deleting,
1201 ;; to preserve the window start.
1202 (let ((line (tar-header-block-summarize tokens t)))
1203 (if (multibyte-string-p line)
1204 (insert-before-markers (string-as-unibyte line) "\n")
1205 (insert-before-markers line "\n")))
1206 (delete-region p after)
1207 (setq tar-header-offset (marker-position m)))
1209 ;; after doing the insertion, add any final padding that may be necessary.
1210 (tar-pad-to-blocksize))
1211 (narrow-to-region (point-min) tar-header-offset)
1212 (set-buffer-multibyte tar-buffer-multibyte)))
1213 (set-buffer-modified-p t) ; mark the tar file as modified
1215 (set-buffer subfile)
1216 ;; Restore the buffer multibyteness.
1217 (set-buffer-multibyte subfile-multibyte)
1218 (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
1219 (message "Saved into tar-buffer `%s'. Be sure to save that buffer!"
1220 (buffer-name tar-superior-buffer))
1221 ;; Prevent basic-save-buffer from changing our coding-system.
1222 (setq last-coding-system-used buffer-file-coding-system)
1223 ;; Prevent ordinary saving from happening.
1227 ;; When this function is called, it is sure that the buffer is unibyte.
1228 (defun tar-pad-to-blocksize ()
1229 "If we are being anal about tar file blocksizes, fix up the current buffer.
1230 Leaves the region wide."
1231 (if (null tar-anal-blocksize)
1234 (let* ((last-desc (nth (1- (length tar-parse-info)) tar-parse-info))
1235 (start (tar-desc-data-start last-desc))
1236 (tokens (tar-desc-tokens last-desc))
1237 (link-p (tar-header-link-type tokens))
1238 (size (if link-p 0 (tar-header-size tokens)))
1239 (data-end (+ start size))
1240 (bbytes (ash tar-anal-blocksize 9))
1241 (pad-to (+ bbytes (* bbytes (/ (1- data-end) bbytes))))
1242 (inhibit-read-only t) ; ##
1244 ;; If the padding after the last data is too long, delete some;
1245 ;; else insert some until we are padded out to the right number of blocks.
1247 (goto-char (+ (or tar-header-offset 0) data-end))
1248 (if (> (1+ (buffer-size)) (+ (or tar-header-offset 0) pad-to))
1249 (delete-region (+ (or tar-header-offset 0) pad-to) (1+ (buffer-size)))
1250 (insert (make-string (- (+ (or tar-header-offset 0) pad-to)
1256 ;; Used in write-file-hook to write tar-files out correctly.
1257 (defun tar-mode-write-file ()
1261 ;; Doing this here confuses things - the region gets left too wide!
1262 ;; I suppose this is run in a context where changing the buffer is bad.
1263 ;; (tar-pad-to-blocksize)
1264 ;; tar-header-offset turns out to be null for files fetched with W3,
1266 (let ((coding-system-for-write 'no-conversion))
1267 (write-region (if tar-header-offset
1268 (byte-to-position tar-header-offset)
1271 buffer-file-name nil t))
1272 (tar-clear-modification-flags)
1273 (set-buffer-modified-p nil))
1274 (narrow-to-region (point-min) (byte-to-position tar-header-offset)))
1275 ;; Return t because we've written the file.
1280 ;;; arch-tag: 8a585a4a-340e-42c2-89e7-d3b1013a4b78
1281 ;;; tar-mode.el ends here