lisp/tar-mode.el

   1 ;;; tar-mode.el --- simple editing of tar files from GNU emacs
   2
   3 ;; Copyright (C) 1990, 1991, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4 ;;   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   5
   6 ;; Author: Jamie Zawinski <jwz@lucid.com>
   7 ;; Maintainer: FSF
   8 ;; Created: 04 Apr 1990
   9 ;; Keywords: unix
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 2, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  26 ;; Boston, MA 02110-1301, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; 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.
  40
  41 ;; This code now understands the extra fields that GNU tar adds to tar files.
  42
  43 ;; This interacts correctly with "uncompress.el" in the Emacs library,
  44 ;; which you get with
  45 ;;
  46 ;;  (autoload 'uncompress-while-visiting "uncompress")
  47 ;;  (setq auto-mode-alist (cons '("\\.Z$" . uncompress-while-visiting)
  48 ;;                         auto-mode-alist))
  49 ;;
  50 ;; Do not attempt to use tar-mode.el with crypt.el, you will lose.
  51
  52 ;;    ***************   TO DO   ***************
  53 ;;
  54 ;; o  chmod should understand "a+x,og-w".
  55 ;;
  56 ;; o  It's not possible to add a NEW file to a tar archive; not that
  57 ;;    important, but still...
  58 ;;
  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.
  62 ;;
  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.)
  66 ;;
  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.
  71 ;;
  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
  77 ;;    the list.
  78 ;;
  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.
  81
  82 ;; Rationale:
  83
  84 ;; Why does tar-mode edit the file itself instead of using tar?
  85
  86 ;; That means that you can edit tar files which you don't have room for
  87 ;; on your local disk.
  88
  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.
  95
  96 ;;; Code:
  97
  98 (defgroup tar nil
  99   "Simple editing of tar files."
 100   :prefix "tar-"
 101   :group 'data)
 102
 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))
 112   :group 'tar)
 113
 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."
 122   :type 'boolean
 123   :group 'tar)
 124
 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."
 128   :type 'boolean
 129   :group 'tar)
 130
 131 (defvar tar-parse-info nil)
 132 (defvar tar-header-offset nil)
 133 (defvar tar-superior-buffer nil)
 134 (defvar tar-superior-descriptor nil)
 135 (defvar tar-subfile-mode nil)
 136 (defvar tar-file-name-coding-system nil)
 137
 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)
 142 (put 'tar-file-name-coding-system 'permanent-local t)
 143 \f
 144 (defmacro tar-setf (form val)
 145   "A mind-numbingly simple implementation of setf."
 146   (let ((mform (macroexpand form (and (boundp 'byte-compile-macro-environment)
 147                                       byte-compile-macro-environment))))
 148     (cond ((symbolp mform) (list 'setq mform val))
 149           ((not (consp mform)) (error "can't setf %s" form))
 150           ((eq (car mform) 'aref)
 151            (list 'aset (nth 1 mform) (nth 2 mform) val))
 152           ((eq (car mform) 'car)
 153            (list 'setcar (nth 1 mform) val))
 154           ((eq (car mform) 'cdr)
 155            (list 'setcdr (nth 1 mform) val))
 156           (t (error "don't know how to setf %s" form)))))
 157 \f
 158 ;;; down to business.
 159
 160 (defmacro make-tar-header (name mode uid git size date ck lt ln
 161                            magic uname gname devmaj devmin)
 162   (list 'vector name mode uid git size date ck lt ln
 163         magic uname gname devmaj devmin))
 164
 165 (defmacro tar-header-name (x) (list 'aref x 0))
 166 (defmacro tar-header-mode (x) (list 'aref x 1))
 167 (defmacro tar-header-uid  (x) (list 'aref x 2))
 168 (defmacro tar-header-gid  (x) (list 'aref x 3))
 169 (defmacro tar-header-size (x) (list 'aref x 4))
 170 (defmacro tar-header-date (x) (list 'aref x 5))
 171 (defmacro tar-header-checksum  (x) (list 'aref x 6))
 172 (defmacro tar-header-link-type (x) (list 'aref x 7))
 173 (defmacro tar-header-link-name (x) (list 'aref x 8))
 174 (defmacro tar-header-magic (x) (list 'aref x 9))
 175 (defmacro tar-header-uname (x) (list 'aref x 10))
 176 (defmacro tar-header-gname (x) (list 'aref x 11))
 177 (defmacro tar-header-dmaj (x) (list 'aref x 12))
 178 (defmacro tar-header-dmin (x) (list 'aref x 13))
 179
 180 (defmacro make-tar-desc (data-start tokens)
 181   (list 'cons data-start tokens))
 182
 183 (defmacro tar-desc-data-start (x) (list 'car x))
 184 (defmacro tar-desc-tokens     (x) (list 'cdr x))
 185
 186 (defconst tar-name-offset 0)
 187 (defconst tar-mode-offset (+ tar-name-offset 100))
 188 (defconst tar-uid-offset  (+ tar-mode-offset 8))
 189 (defconst tar-gid-offset  (+ tar-uid-offset 8))
 190 (defconst tar-size-offset (+ tar-gid-offset 8))
 191 (defconst tar-time-offset (+ tar-size-offset 12))
 192 (defconst tar-chk-offset  (+ tar-time-offset 12))
 193 (defconst tar-linkp-offset (+ tar-chk-offset 8))
 194 (defconst tar-link-offset (+ tar-linkp-offset 1))
 195 ;;; GNU-tar specific slots.
 196 (defconst tar-magic-offset (+ tar-link-offset 100))
 197 (defconst tar-uname-offset (+ tar-magic-offset 8))
 198 (defconst tar-gname-offset (+ tar-uname-offset 32))
 199 (defconst tar-dmaj-offset (+ tar-gname-offset 32))
 200 (defconst tar-dmin-offset (+ tar-dmaj-offset 8))
 201 (defconst tar-end-offset (+ tar-dmin-offset 8))
 202
 203 (defun tar-header-block-tokenize (string)
 204   "Return a `tar-header' structure.
 205 This is a list of name, mode, uid, gid, size,
 206 write-date, checksum, link-type, and link-name."
 207   (setq string (string-as-unibyte string))
 208   (cond ((< (length string) 512) nil)
 209         (;(some 'plusp string)           ; <-- oops, massive cycle hog!
 210          (or (not (= 0 (aref string 0))) ; This will do.
 211              (not (= 0 (aref string 101))))
 212          (let* ((name-end (1- tar-mode-offset))
 213                 (link-end (1- tar-magic-offset))
 214                 (uname-end (1- tar-gname-offset))
 215                 (gname-end (1- tar-dmaj-offset))
 216                 (link-p (aref string tar-linkp-offset))
 217                 (magic-str (substring string tar-magic-offset (1- tar-uname-offset)))
 218                 (uname-valid-p (or (string= "ustar  " magic-str) (string= "GNUtar " magic-str)))
 219                 name linkname
 220                 (nulsexp   "[^\000]*\000"))
 221            (when (string-match nulsexp string tar-name-offset)
 222              (setq name-end (min name-end (1- (match-end 0)))))
 223            (when (string-match nulsexp string tar-link-offset)
 224              (setq link-end (min link-end (1- (match-end 0)))))
 225            (when (string-match nulsexp string tar-uname-offset)
 226              (setq uname-end (min uname-end (1- (match-end 0)))))
 227            (when (string-match nulsexp string tar-gname-offset)
 228              (setq gname-end (min gname-end (1- (match-end 0)))))
 229            (setq name (substring string tar-name-offset name-end)
 230                  link-p (if (or (= link-p 0) (= link-p ?0))
 231                             nil
 232                           (- link-p ?0)))
 233            (setq linkname (substring string tar-link-offset link-end))
 234            (if default-enable-multibyte-characters
 235                (setq name
 236                      (decode-coding-string name tar-file-name-coding-system)
 237                      linkname
 238                      (decode-coding-string linkname
 239                                            tar-file-name-coding-system)))
 240            (if (and (null link-p) (string-match "/\\'" name)) (setq link-p 5)) ; directory
 241            (make-tar-header
 242              name
 243              (tar-parse-octal-integer string tar-mode-offset tar-uid-offset)
 244              (tar-parse-octal-integer string tar-uid-offset tar-gid-offset)
 245              (tar-parse-octal-integer string tar-gid-offset tar-size-offset)
 246              (tar-parse-octal-integer string tar-size-offset tar-time-offset)
 247              (tar-parse-octal-long-integer string tar-time-offset tar-chk-offset)
 248              (tar-parse-octal-integer string tar-chk-offset tar-linkp-offset)
 249              link-p
 250              linkname
 251              uname-valid-p
 252              (and uname-valid-p (substring string tar-uname-offset uname-end))
 253              (and uname-valid-p (substring string tar-gname-offset gname-end))
 254              (tar-parse-octal-integer string tar-dmaj-offset tar-dmin-offset)
 255              (tar-parse-octal-integer string tar-dmin-offset tar-end-offset)
 256              )))
 257         (t 'empty-tar-block)))
 258
 259
 260 (defun tar-parse-octal-integer (string &optional start end)
 261   (if (null start) (setq start 0))
 262   (if (null end) (setq end (length string)))
 263   (if (= (aref string start) 0)
 264       0
 265     (let ((n 0))
 266       (while (< start end)
 267         (setq n (if (< (aref string start) ?0) n
 268                   (+ (* n 8) (- (aref string start) ?0)))
 269               start (1+ start)))
 270       n)))
 271
 272 (defun tar-parse-octal-long-integer (string &optional start end)
 273   (if (null start) (setq start 0))
 274   (if (null end) (setq end (length string)))
 275   (if (= (aref string start) 0)
 276       (list 0 0)
 277     (let ((lo 0)
 278           (hi 0))
 279       (while (< start end)
 280         (if (>= (aref string start) ?0)
 281             (setq lo (+ (* lo 8) (- (aref string start) ?0))
 282                   hi (+ (* hi 8) (ash lo -16))
 283                   lo (logand lo 65535)))
 284         (setq start (1+ start)))
 285       (list hi lo))))
 286
 287 (defun tar-parse-octal-integer-safe (string)
 288   (if (zerop (length string)) (error "empty string"))
 289   (mapc (lambda (c)
 290           (if (or (< c ?0) (> c ?7))
 291               (error "`%c' is not an octal digit" c)))
 292         string)
 293   (tar-parse-octal-integer string))
 294
 295
 296 (defun tar-header-block-checksum (string)
 297   "Compute and return a tar-acceptable checksum for this block."
 298   (setq string (string-as-unibyte string))
 299   (let* ((chk-field-start tar-chk-offset)
 300          (chk-field-end (+ chk-field-start 8))
 301          (sum 0)
 302          (i 0))
 303     ;; Add up all of the characters except the ones in the checksum field.
 304     ;; Add that field as if it were filled with spaces.
 305     (while (< i chk-field-start)
 306       (setq sum (+ sum (aref string i))
 307             i (1+ i)))
 308     (setq i chk-field-end)
 309     (while (< i 512)
 310       (setq sum (+ sum (aref string i))
 311             i (1+ i)))
 312     (+ sum (* 32 8))))
 313
 314 (defun tar-header-block-check-checksum (hblock desired-checksum file-name)
 315   "Beep and print a warning if the checksum doesn't match."
 316   (if (not (= desired-checksum (tar-header-block-checksum hblock)))
 317       (progn (beep) (message "Invalid checksum for file %s!" file-name))))
 318
 319 (defun tar-clip-time-string (time)
 320   (let ((str (current-time-string time)))
 321     (concat " " (substring str 4 16) (substring str 19 24))))
 322
 323 (defun tar-grind-file-mode (mode)
 324   "Construct a `-rw--r--r--' string indicating MODE.
 325 MODE should be an integer which is a file mode value."
 326   (string
 327    (if (zerop (logand 256 mode)) ?- ?r)
 328    (if (zerop (logand 128 mode)) ?- ?w)
 329    (if (zerop (logand 1024 mode)) (if (zerop (logand  64 mode)) ?- ?x) ?s)
 330    (if (zerop (logand  32 mode)) ?- ?r)
 331    (if (zerop (logand  16 mode)) ?- ?w)
 332    (if (zerop (logand 2048 mode)) (if (zerop (logand   8 mode)) ?- ?x) ?s)
 333    (if (zerop (logand   4 mode)) ?- ?r)
 334    (if (zerop (logand   2 mode)) ?- ?w)
 335    (if (zerop (logand   1 mode)) ?- ?x)))
 336
 337 (defun tar-header-block-summarize (tar-hblock &optional mod-p)
 338   "Return a line similar to the output of `tar -vtf'."
 339   (let ((name (tar-header-name tar-hblock))
 340         (mode (tar-header-mode tar-hblock))
 341         (uid (tar-header-uid tar-hblock))
 342         (gid (tar-header-gid tar-hblock))
 343         (uname (tar-header-uname tar-hblock))
 344         (gname (tar-header-gname tar-hblock))
 345         (size (tar-header-size tar-hblock))
 346         (time (tar-header-date tar-hblock))
 347         ;; (ck (tar-header-checksum tar-hblock))
 348         (type (tar-header-link-type tar-hblock))
 349         (link-name (tar-header-link-name tar-hblock)))
 350     (format "%c%c%s%8s/%-8s%7s%s %s%s"
 351             (if mod-p ?* ? )
 352             (cond ((or (eq type nil) (eq type 0)) ?-)
 353                   ((eq type 1) ?h)      ; link
 354                   ((eq type 2) ?l)      ; symlink
 355                   ((eq type 3) ?c)      ; char special
 356                   ((eq type 4) ?b)      ; block special
 357                   ((eq type 5) ?d)      ; directory
 358                   ((eq type 6) ?p)      ; FIFO/pipe
 359                   ((eq type 20) ?*)     ; directory listing
 360                   ((eq type 28) ?L)     ; next has longname
 361                   ((eq type 29) ?M)     ; multivolume continuation
 362                   ((eq type 35) ?S)     ; sparse
 363                   ((eq type 38) ?V)     ; volume header
 364                   ((eq type 55) ?H)     ; extended pax header
 365                   (t ?\s)
 366                   )
 367             (tar-grind-file-mode mode)
 368             (if (= 0 (length uname)) uid uname)
 369             (if (= 0 (length gname)) gid gname)
 370             size
 371             (if tar-mode-show-date (tar-clip-time-string time) "")
 372             (propertize name
 373                         'mouse-face 'highlight
 374                         'help-echo "mouse-2: extract this file into a buffer")
 375             (if (or (eq type 1) (eq type 2))
 376                 (concat (if (= type 1) " ==> " " --> ") link-name)
 377               ""))))
 378
 379 (defun tar-untar-buffer ()
 380   "Extract all archive members in the tar-file into the current directory."
 381   (interactive)
 382   (let ((multibyte enable-multibyte-characters))
 383     (unwind-protect
 384         (save-restriction
 385           (widen)
 386           (set-buffer-multibyte nil)
 387           (dolist (descriptor tar-parse-info)
 388             (let* ((tokens (tar-desc-tokens descriptor))
 389                    (name (tar-header-name tokens))
 390                    (dir (file-name-directory name))
 391                    (start (+ (tar-desc-data-start descriptor)
 392                              (- tar-header-offset (point-min))))
 393                    (end (+ start (tar-header-size tokens))))
 394               (unless (file-directory-p name)
 395                 (message "Extracting %s" name)
 396                 (if (and dir (not (file-exists-p dir)))
 397                     (make-directory dir t))
 398                 (unless (file-directory-p name)
 399                   (write-region start end name))
 400                 (set-file-modes name (tar-header-mode tokens))))))
 401       (if multibyte
 402           (set-buffer-multibyte 'to)))))
 403
 404 (defun tar-summarize-buffer ()
 405   "Parse the contents of the tar file in the current buffer.
 406 Place a dired-like listing on the front;
 407 then narrow to it, so that only that listing
 408 is visible (and the real data of the buffer is hidden)."
 409   (let ((modified (buffer-modified-p)))
 410     (set-buffer-multibyte nil)
 411     (let* ((result '())
 412            (pos (point-min))
 413            (progress-reporter
 414             (make-progress-reporter "Parsing tar file..."
 415                                     (point-min) (max 1 (- (buffer-size) 1024))))
 416            tokens)
 417       (while (and (<= (+ pos 512) (point-max))
 418                   (not (eq 'empty-tar-block
 419                            (setq tokens
 420                                  (tar-header-block-tokenize
 421                                   (buffer-substring pos (+ pos 512)))))))
 422         (setq pos (+ pos 512))
 423         (progress-reporter-update progress-reporter pos)
 424         (if (memq (tar-header-link-type tokens) '(20 55))
 425             ;; Foo.  There's an extra empty block after these.
 426             (setq pos (+ pos 512)))
 427         (let ((size (tar-header-size tokens)))
 428           (if (< size 0)
 429               (error "%s has size %s - corrupted"
 430                      (tar-header-name tokens) size))
 431           ;;
 432           ;; This is just too slow.  Don't really need it anyway....
 433           ;;(tar-header-block-check-checksum
 434           ;;  hblock (tar-header-block-checksum hblock)
 435           ;;  (tar-header-name tokens))
 436
 437           (push (make-tar-desc pos tokens) result)
 438
 439           (and (null (tar-header-link-type tokens))
 440                (> size 0)
 441                (setq pos
 442                      (+ pos 512 (ash (ash (1- size) -9) 9)) ; this works
 443                      ;;(+ pos (+ size (- 512 (rem (1- size) 512)))) ; this doesn't
 444                      ))))
 445       (make-local-variable 'tar-parse-info)
 446       (setq tar-parse-info (nreverse result))
 447       ;; A tar file should end with a block or two of nulls,
 448       ;; but let's not get a fatal error if it doesn't.
 449       (if (eq tokens 'empty-tar-block)
 450           (progress-reporter-done progress-reporter)
 451         (message "Warning: premature EOF parsing tar file")))
 452     ;; Obey the user's preference for the use of uni/multibytes.
 453     (if default-enable-multibyte-characters
 454         (set-buffer-multibyte 'to))
 455     (goto-char (point-min))
 456     (let ((inhibit-read-only t)
 457           ;; Collect summary lines and insert them all at once since tar files
 458           ;; can be pretty big.
 459           (total-summaries
 460            (mapconcat
 461             (lambda (tar-desc)
 462               (tar-header-block-summarize (tar-desc-tokens tar-desc)))
 463             tar-parse-info
 464             "\n")))
 465       (insert total-summaries "\n"))
 466     (narrow-to-region (point-min) (point))
 467     (set (make-local-variable 'tar-header-offset) (position-bytes (point)))
 468     (goto-char (point-min))
 469     (restore-buffer-modified-p modified)))
 470 \f
 471 (defvar tar-mode-map
 472   (let ((map (make-keymap)))
 473     (suppress-keymap map)
 474     (define-key map " " 'tar-next-line)
 475     (define-key map "C" 'tar-copy)
 476     (define-key map "d" 'tar-flag-deleted)
 477     (define-key map "\^D" 'tar-flag-deleted)
 478     (define-key map "e" 'tar-extract)
 479     (define-key map "f" 'tar-extract)
 480     (define-key map "\C-m" 'tar-extract)
 481     (define-key map [mouse-2] 'tar-mouse-extract)
 482     (define-key map "g" 'revert-buffer)
 483     (define-key map "h" 'describe-mode)
 484     (define-key map "n" 'tar-next-line)
 485     (define-key map "\^N" 'tar-next-line)
 486     (define-key map [down] 'tar-next-line)
 487     (define-key map "o" 'tar-extract-other-window)
 488     (define-key map "p" 'tar-previous-line)
 489     (define-key map "q" 'quit-window)
 490     (define-key map "\^P" 'tar-previous-line)
 491     (define-key map [up] 'tar-previous-line)
 492     (define-key map "R" 'tar-rename-entry)
 493     (define-key map "u" 'tar-unflag)
 494     (define-key map "v" 'tar-view)
 495     (define-key map "x" 'tar-expunge)
 496     (define-key map "\177" 'tar-unflag-backwards)
 497     (define-key map "E" 'tar-extract-other-window)
 498     (define-key map "M" 'tar-chmod-entry)
 499     (define-key map "G" 'tar-chgrp-entry)
 500     (define-key map "O" 'tar-chown-entry)
 501 \f
 502     ;; Make menu bar items.
 503
 504     ;; Get rid of the Edit menu bar item to save space.
 505     (define-key map [menu-bar edit] 'undefined)
 506
 507     (define-key map [menu-bar immediate]
 508   (cons "Immediate" (make-sparse-keymap "Immediate")))
 509
 510     (define-key map [menu-bar immediate view]
 511   '("View This File" . tar-view))
 512     (define-key map [menu-bar immediate display]
 513   '("Display in Other Window" . tar-display-other-window))
 514     (define-key map [menu-bar immediate find-file-other-window]
 515   '("Find in Other Window" . tar-extract-other-window))
 516     (define-key map [menu-bar immediate find-file]
 517   '("Find This File" . tar-extract))
 518
 519     (define-key map [menu-bar mark]
 520   (cons "Mark" (make-sparse-keymap "Mark")))
 521
 522     (define-key map [menu-bar mark unmark-all]
 523   '("Unmark All" . tar-clear-modification-flags))
 524     (define-key map [menu-bar mark deletion]
 525   '("Flag" . tar-flag-deleted))
 526     (define-key map [menu-bar mark unmark]
 527   '("Unflag" . tar-unflag))
 528
 529     (define-key map [menu-bar operate]
 530   (cons "Operate" (make-sparse-keymap "Operate")))
 531
 532     (define-key map [menu-bar operate chown]
 533   '("Change Owner..." . tar-chown-entry))
 534     (define-key map [menu-bar operate chgrp]
 535   '("Change Group..." . tar-chgrp-entry))
 536     (define-key map [menu-bar operate chmod]
 537   '("Change Mode..." . tar-chmod-entry))
 538     (define-key map [menu-bar operate rename]
 539   '("Rename to..." . tar-rename-entry))
 540     (define-key map [menu-bar operate copy]
 541   '("Copy to..." . tar-copy))
 542     (define-key map [menu-bar operate expunge]
 543   '("Expunge Marked Files" . tar-expunge))
 544 \f
 545     map)
 546   "Local keymap for Tar mode listings.")
 547
 548 \f
 549 ;; tar mode is suitable only for specially formatted data.
 550 (put 'tar-mode 'mode-class 'special)
 551 (put 'tar-subfile-mode 'mode-class 'special)
 552
 553 ;;;###autoload
 554 (define-derived-mode tar-mode nil "Tar"
 555   "Major mode for viewing a tar file as a dired-like listing of its contents.
 556 You can move around using the usual cursor motion commands.
 557 Letters no longer insert themselves.
 558 Type `e' to pull a file out of the tar file and into its own buffer;
 559 or click mouse-2 on the file's line in the Tar mode buffer.
 560 Type `c' to copy an entry from the tar file into another file on disk.
 561
 562 If you edit a sub-file of this archive (as with the `e' command) and
 563 save it with \\[save-buffer], the contents of that buffer will be
 564 saved back into the tar-file buffer; in this way you can edit a file
 565 inside of a tar archive without extracting it and re-archiving it.
 566
 567 See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
 568 \\{tar-mode-map}"
 569   ;; this is not interactive because you shouldn't be turning this
 570   ;; mode on and off.  You can corrupt things that way.
 571   ;; rms: with permanent locals, it should now be possible to make this work
 572   ;; interactively in some reasonable fashion.
 573   (make-local-variable 'tar-header-offset)
 574   (make-local-variable 'tar-parse-info)
 575   (set (make-local-variable 'require-final-newline) nil) ; binary data, dude...
 576   (set (make-local-variable 'revert-buffer-function) 'tar-mode-revert)
 577   (set (make-local-variable 'local-enable-local-variables) nil)
 578   (set (make-local-variable 'next-line-add-newlines) nil)
 579   (set (make-local-variable 'tar-file-name-coding-system)
 580        (or file-name-coding-system
 581            default-file-name-coding-system
 582            locale-coding-system))
 583   ;; Prevent loss of data when saving the file.
 584   (set (make-local-variable 'file-precious-flag) t)
 585   (auto-save-mode 0)
 586   (set (make-local-variable 'write-contents-functions) '(tar-mode-write-file))
 587   (buffer-disable-undo)
 588   (widen)
 589   (if (and (boundp 'tar-header-offset) tar-header-offset)
 590       (narrow-to-region (point-min) tar-header-offset)
 591     (tar-summarize-buffer)
 592     (tar-next-line 0)))
 593
 594
 595 (defun tar-subfile-mode (p)
 596   "Minor mode for editing an element of a tar-file.
 597 This mode arranges for \"saving\" this buffer to write the data
 598 into the tar-file buffer that it came from.  The changes will actually
 599 appear on disk when you save the tar-file's buffer."
 600   (interactive "P")
 601   (or (and (boundp 'tar-superior-buffer) tar-superior-buffer)
 602       (error "This buffer is not an element of a tar file"))
 603   ;; Don't do this, because it is redundant and wastes mode line space.
 604   ;;  (or (assq 'tar-subfile-mode minor-mode-alist)
 605   ;;      (setq minor-mode-alist (append minor-mode-alist
 606   ;;                                 (list '(tar-subfile-mode " TarFile")))))
 607   (make-local-variable 'tar-subfile-mode)
 608   (setq tar-subfile-mode
 609         (if (null p)
 610             (not tar-subfile-mode)
 611             (> (prefix-numeric-value p) 0)))
 612   (cond (tar-subfile-mode
 613          (add-hook 'write-file-functions 'tar-subfile-save-buffer nil t)
 614          ;; turn off auto-save.
 615          (auto-save-mode -1)
 616          (setq buffer-auto-save-file-name nil)
 617          (run-hooks 'tar-subfile-mode-hook))
 618         (t
 619          (remove-hook 'write-file-functions 'tar-subfile-save-buffer t))))
 620
 621
 622 ;; Revert the buffer and recompute the dired-like listing.
 623 (defun tar-mode-revert (&optional no-auto-save no-confirm)
 624   (let ((revert-buffer-function nil)
 625         (old-offset tar-header-offset)
 626         success)
 627     (setq tar-header-offset nil)
 628     (unwind-protect
 629         (and (revert-buffer t no-confirm)
 630              (progn (widen)
 631                     (setq success t)
 632                     (tar-mode)))
 633       ;; If the revert was canceled,
 634       ;; put back the old value of tar-header-offset.
 635       (or success
 636           (setq tar-header-offset old-offset)))))
 637
 638
 639 (defun tar-next-line (arg)
 640   "Move cursor vertically down ARG lines and to the start of the filename."
 641   (interactive "p")
 642   (forward-line arg)
 643   (if (eobp) nil (forward-char (if tar-mode-show-date 54 36))))
 644
 645 (defun tar-previous-line (arg)
 646   "Move cursor vertically up ARG lines and to the start of the filename."
 647   (interactive "p")
 648   (tar-next-line (- arg)))
 649
 650 (defun tar-current-descriptor (&optional noerror)
 651   "Return the tar-descriptor of the current line, or signals an error."
 652   ;; I wish lines had plists, like in ZMACS...
 653   (or (nth (count-lines (point-min)
 654                         (save-excursion (beginning-of-line) (point)))
 655            tar-parse-info)
 656       (if noerror
 657           nil
 658           (error "This line does not describe a tar-file entry"))))
 659
 660 (defun tar-get-descriptor ()
 661   (let* ((descriptor (tar-current-descriptor))
 662          (tokens (tar-desc-tokens descriptor))
 663          (size (tar-header-size tokens))
 664          (link-p (tar-header-link-type tokens)))
 665     (if link-p
 666         (error "This is %s, not a real file"
 667                (cond ((eq link-p 5) "a directory")
 668                      ((eq link-p 20) "a tar directory header")
 669                      ((eq link-p 28) "a next has longname")
 670                      ((eq link-p 29) "a multivolume-continuation")
 671                      ((eq link-p 35) "a sparse entry")
 672                      ((eq link-p 38) "a volume header")
 673                      ((eq link-p 55) "an extended pax header")
 674                      (t "a link"))))
 675     (if (zerop size) (message "This is a zero-length file"))
 676     descriptor))
 677
 678 (defun tar-mouse-extract (event)
 679   "Extract a file whose tar directory line you click on."
 680   (interactive "e")
 681   (save-excursion
 682     (set-buffer (window-buffer (posn-window (event-end event))))
 683     (save-excursion
 684       (goto-char (posn-point (event-end event)))
 685       ;; Just make sure this doesn't get an error.
 686       (tar-get-descriptor)))
 687   (select-window (posn-window (event-end event)))
 688   (goto-char (posn-point (event-end event)))
 689   (tar-extract))
 690
 691 (defun tar-file-name-handler (op &rest args)
 692   "Helper function for `tar-extract'."
 693   (or (eq op 'file-exists-p)
 694       (let ((file-name-handler-alist nil))
 695         (apply op args))))
 696
 697 (defun tar-extract (&optional other-window-p)
 698   "In Tar mode, extract this entry of the tar file into its own buffer."
 699   (interactive)
 700   (let* ((view-p (eq other-window-p 'view))
 701          (descriptor (tar-get-descriptor))
 702          (tokens (tar-desc-tokens descriptor))
 703          (name (tar-header-name tokens))
 704          (size (tar-header-size tokens))
 705          (start (+ (tar-desc-data-start descriptor)
 706                    (- tar-header-offset (point-min))))
 707          (end (+ start size)))
 708     (let* ((tar-buffer (current-buffer))
 709            (tarname (buffer-name))
 710            (bufname (concat (file-name-nondirectory name)
 711                             " ("
 712                              tarname
 713                              ")"))
 714            (read-only-p (or buffer-read-only view-p))
 715            (new-buffer-file-name (expand-file-name
 716                                   ;; `:' is not allowed on Windows
 717                                   (concat tarname "!" name)))
 718            (buffer (get-file-buffer new-buffer-file-name))
 719            (just-created nil)
 720            (pos (point))
 721            undo-list)
 722       (unless buffer
 723         (setq buffer (generate-new-buffer bufname))
 724         (save-excursion
 725           (set-buffer buffer)
 726           (setq undo-list buffer-undo-list
 727                 buffer-undo-list t))
 728         (setq bufname (buffer-name buffer))
 729         (setq just-created t)
 730         (unwind-protect
 731             (let (coding)
 732               (narrow-to-region start end)
 733               (goto-char start)
 734               (setq coding (or coding-system-for-read
 735                                (and set-auto-coding-function
 736                                     (funcall set-auto-coding-function
 737                                              name (- end start)))
 738                                ;; The following binding causes
 739                                ;; find-buffer-file-type-coding-system
 740                                ;; (defined on dos-w32.el) to act as if
 741                                ;; the file being extracted existed, so
 742                                ;; that the file's contents' encoding and
 743                                ;; EOL format are auto-detected.
 744                                (let ((file-name-handler-alist
 745                                       '(("" . tar-file-name-handler))))
 746                                  (car (find-operation-coding-system
 747                                        'insert-file-contents
 748                                        (cons name (current-buffer)) t)))))
 749               (if (or (not coding)
 750                       (eq (coding-system-type coding) 'undecided))
 751                   (setq coding (detect-coding-region start end t)))
 752               (if (and default-enable-multibyte-characters
 753                        (coding-system-get coding :for-unibyte))
 754                   (save-excursion
 755                     (set-buffer buffer)
 756                     (set-buffer-multibyte nil)))
 757               (widen)
 758               (decode-coding-region start end coding buffer)
 759               (save-excursion
 760                 (set-buffer buffer)
 761                 (goto-char (point-min))
 762                 (setq buffer-file-name new-buffer-file-name)
 763                 (setq buffer-file-truename
 764                       (abbreviate-file-name buffer-file-name))
 765                 ;; Force buffer-file-coding-system to what
 766                 ;; decode-coding-region actually used.
 767                 (set-buffer-file-coding-system last-coding-system-used t)
 768                 ;; Set the default-directory to the dir of the
 769                 ;; superior buffer.
 770                 (setq default-directory
 771                       (save-excursion
 772                         (set-buffer tar-buffer)
 773                         default-directory))
 774                 (normal-mode)  ; pick a mode.
 775                 (rename-buffer bufname)
 776                 (make-local-variable 'tar-superior-buffer)
 777                 (make-local-variable 'tar-superior-descriptor)
 778                 (setq tar-superior-buffer tar-buffer)
 779                 (setq tar-superior-descriptor descriptor)
 780                 (setq buffer-read-only read-only-p)
 781                 (set-buffer-modified-p nil)
 782                 (setq buffer-undo-list undo-list)
 783                 (tar-subfile-mode 1))
 784               (set-buffer tar-buffer))
 785           (narrow-to-region (point-min) tar-header-offset)
 786           (goto-char pos)))
 787       (if view-p
 788           (view-buffer buffer (and just-created 'kill-buffer))
 789         (if (eq other-window-p 'display)
 790             (display-buffer buffer)
 791           (if other-window-p
 792               (switch-to-buffer-other-window buffer)
 793             (switch-to-buffer buffer)))))))
 794
 795
 796 (defun tar-extract-other-window ()
 797   "In Tar mode, find this entry of the tar file in another window."
 798   (interactive)
 799   (tar-extract t))
 800
 801 (defun tar-display-other-window ()
 802   "In Tar mode, display this entry of the tar file in another window."
 803   (interactive)
 804   (tar-extract 'display))
 805
 806 (defun tar-view ()
 807   "In Tar mode, view the tar file entry on this line."
 808   (interactive)
 809   (tar-extract 'view))
 810
 811
 812 (defun tar-read-file-name (&optional prompt)
 813   "Read a file name with this line's entry as the default."
 814   (or prompt (setq prompt "Copy to: "))
 815   (let* ((default-file (expand-file-name
 816                         (tar-header-name (tar-desc-tokens
 817                                           (tar-current-descriptor)))))
 818          (target (expand-file-name
 819                   (read-file-name prompt
 820                                   (file-name-directory default-file)
 821                                   default-file nil))))
 822     (if (or (string= "" (file-name-nondirectory target))
 823             (file-directory-p target))
 824         (setq target (concat (if (string-match "/$" target)
 825                                  (substring target 0 (1- (match-end 0)))
 826                                  target)
 827                              "/"
 828                              (file-name-nondirectory default-file))))
 829     target))
 830
 831
 832 (defun tar-copy (&optional to-file)
 833   "In Tar mode, extract this entry of the tar file into a file on disk.
 834 If TO-FILE is not supplied, it is prompted for, defaulting to the name of
 835 the current tar-entry."
 836   (interactive (list (tar-read-file-name)))
 837   (let* ((descriptor (tar-get-descriptor))
 838          (tokens (tar-desc-tokens descriptor))
 839          (name (tar-header-name tokens))
 840          (size (tar-header-size tokens))
 841          (start (+ (tar-desc-data-start descriptor)
 842                    (- tar-header-offset (point-min))))
 843          (end (+ start size))
 844          (inhibit-file-name-handlers inhibit-file-name-handlers)
 845          (inhibit-file-name-operation inhibit-file-name-operation))
 846     (save-restriction
 847       (widen)
 848       ;; Inhibit compressing a subfile again if *both* name and
 849       ;; to-file are handled by jka-compr
 850       (if (and (eq (find-file-name-handler name 'write-region) 'jka-compr-handler)
 851                (eq (find-file-name-handler to-file 'write-region) 'jka-compr-handler))
 852           (setq inhibit-file-name-handlers
 853                 (cons 'jka-compr-handler
 854                       (and (eq inhibit-file-name-operation 'write-region)
 855                            inhibit-file-name-handlers))
 856                 inhibit-file-name-operation 'write-region))
 857       (let ((coding-system-for-write 'no-conversion))
 858         (write-region start end to-file nil nil nil t)))
 859     (message "Copied tar entry %s to %s" name to-file)))
 860
 861 (defun tar-flag-deleted (p &optional unflag)
 862   "In Tar mode, mark this sub-file to be deleted from the tar file.
 863 With a prefix argument, mark that many files."
 864   (interactive "p")
 865   (beginning-of-line)
 866   (dotimes (i (abs p))
 867     (if (tar-current-descriptor unflag) ; barf if we're not on an entry-line.
 868         (progn
 869           (delete-char 1)
 870           (insert (if unflag " " "D"))))
 871     (forward-line (if (< p 0) -1 1)))
 872   (if (eobp) nil (forward-char 36)))
 873
 874 (defun tar-unflag (p)
 875   "In Tar mode, un-mark this sub-file if it is marked to be deleted.
 876 With a prefix argument, un-mark that many files forward."
 877   (interactive "p")
 878   (tar-flag-deleted p t))
 879
 880 (defun tar-unflag-backwards (p)
 881   "In Tar mode, un-mark this sub-file if it is marked to be deleted.
 882 With a prefix argument, un-mark that many files backward."
 883   (interactive "p")
 884   (tar-flag-deleted (- p) t))
 885
 886
 887 (defun tar-expunge-internal ()
 888   "Expunge the tar-entry specified by the current line."
 889   (let* ((descriptor (tar-current-descriptor))
 890          (tokens (tar-desc-tokens descriptor))
 891          ;; (line (tar-desc-data-start descriptor))
 892          (name (tar-header-name tokens))
 893          (size (tar-header-size tokens))
 894          (link-p (tar-header-link-type tokens))
 895          (start (tar-desc-data-start descriptor))
 896          (following-descs (cdr (memq descriptor tar-parse-info))))
 897     (if link-p (setq size 0)) ; size lies for hard-links.
 898     ;;
 899     ;; delete the current line...
 900     (beginning-of-line)
 901     (let ((line-start (point)))
 902       (end-of-line) (forward-char)
 903       ;; decrement the header-pointer to be in sync...
 904       (setq tar-header-offset (- tar-header-offset (- (point) line-start)))
 905       (delete-region line-start (point)))
 906     ;;
 907     ;; delete the data pointer...
 908     (setq tar-parse-info (delq descriptor tar-parse-info))
 909     ;;
 910     ;; delete the data from inside the file...
 911     (widen)
 912     (let* ((data-start (+ start (- tar-header-offset (point-min)) -512))
 913            (data-end (+ data-start 512 (ash (ash (+ size 511) -9) 9))))
 914       (delete-region data-start data-end)
 915       ;;
 916       ;; and finally, decrement the start-pointers of all following
 917       ;; entries in the archive.  This is a pig when deleting a bunch
 918       ;; of files at once - we could optimize this to only do the
 919       ;; iteration over the files that remain, or only iterate up to
 920       ;; the next file to be deleted.
 921       (let ((data-length (- data-end data-start)))
 922         (dolist (desc following-descs)
 923           (tar-setf (tar-desc-data-start desc)
 924                     (- (tar-desc-data-start desc) data-length))))
 925       ))
 926   (narrow-to-region (point-min) tar-header-offset))
 927
 928
 929 (defun tar-expunge (&optional noconfirm)
 930   "In Tar mode, delete all the archived files flagged for deletion.
 931 This does not modify the disk image; you must save the tar file itself
 932 for this to be permanent."
 933   (interactive)
 934   (if (or noconfirm
 935           (y-or-n-p "Expunge files marked for deletion? "))
 936       (let ((n 0))
 937         (save-excursion
 938           (goto-char (point-min))
 939           (while (not (eobp))
 940             (if (looking-at "D")
 941                 (progn (tar-expunge-internal)
 942                        (setq n (1+ n)))
 943                 (forward-line 1)))
 944           ;; after doing the deletions, add any padding that may be necessary.
 945           (tar-pad-to-blocksize)
 946           (narrow-to-region (point-min) tar-header-offset))
 947         (if (zerop n)
 948             (message "Nothing to expunge.")
 949             (message "%s files expunged.  Be sure to save this buffer." n)))))
 950
 951
 952 (defun tar-clear-modification-flags ()
 953   "Remove the stars at the beginning of each line."
 954   (interactive)
 955   (save-excursion
 956     (goto-char (point-min))
 957     (while (< (point) tar-header-offset)
 958       (if (not (eq (following-char) ?\s))
 959           (progn (delete-char 1) (insert " ")))
 960       (forward-line 1))))
 961
 962
 963 (defun tar-chown-entry (new-uid)
 964   "Change the user-id associated with this entry in the tar file.
 965 If this tar file was written by GNU tar, then you will be able to edit
 966 the user id as a string; otherwise, you must edit it as a number.
 967 You can force editing as a number by calling this with a prefix arg.
 968 This does not modify the disk image; you must save the tar file itself
 969 for this to be permanent."
 970   (interactive (list
 971                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
 972                    (if (or current-prefix-arg
 973                            (not (tar-header-magic tokens)))
 974                        (let (n)
 975                          (while (not (numberp (setq n (read-minibuffer
 976                                                         "New UID number: "
 977                                                         (format "%s" (tar-header-uid tokens)))))))
 978                          n)
 979                        (read-string "New UID string: " (tar-header-uname tokens))))))
 980   (cond ((stringp new-uid)
 981          (tar-setf (tar-header-uname (tar-desc-tokens (tar-current-descriptor)))
 982                    new-uid)
 983          (tar-alter-one-field tar-uname-offset (concat new-uid "\000")))
 984         (t
 985          (tar-setf (tar-header-uid (tar-desc-tokens (tar-current-descriptor)))
 986                    new-uid)
 987          (tar-alter-one-field tar-uid-offset
 988            (concat (substring (format "%6o" new-uid) 0 6) "\000 ")))))
 989
 990
 991 (defun tar-chgrp-entry (new-gid)
 992   "Change the group-id associated with this entry in the tar file.
 993 If this tar file was written by GNU tar, then you will be able to edit
 994 the group id as a string; otherwise, you must edit it as a number.
 995 You can force editing as a number by calling this with a prefix arg.
 996 This does not modify the disk image; you must save the tar file itself
 997 for this to be permanent."
 998   (interactive (list
 999                  (let ((tokens (tar-desc-tokens (tar-current-descriptor))))
1000                    (if (or current-prefix-arg
1001                            (not (tar-header-magic tokens)))
1002                        (let (n)
1003                          (while (not (numberp (setq n (read-minibuffer
1004                                                         "New GID number: "
1005                                                         (format "%s" (tar-header-gid tokens)))))))
1006                          n)
1007                        (read-string "New GID string: " (tar-header-gname tokens))))))
1008   (cond ((stringp new-gid)
1009          (tar-setf (tar-header-gname (tar-desc-tokens (tar-current-descriptor)))
1010                    new-gid)
1011          (tar-alter-one-field tar-gname-offset
1012            (concat new-gid "\000")))
1013         (t
1014          (tar-setf (tar-header-gid (tar-desc-tokens (tar-current-descriptor)))
1015                    new-gid)
1016          (tar-alter-one-field tar-gid-offset
1017            (concat (substring (format "%6o" new-gid) 0 6) "\000 ")))))
1018
1019 (defun tar-rename-entry (new-name)
1020   "Change the name associated with this entry in the tar file.
1021 This does not modify the disk image; you must save the tar file itself
1022 for this to be permanent."
1023   (interactive
1024     (list (read-string "New name: "
1025             (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
1026   (if (string= "" new-name) (error "zero length name"))
1027   (let ((encoded-new-name (encode-coding-string new-name
1028                                                 tar-file-name-coding-system)))
1029     (if (> (length encoded-new-name) 98) (error "name too long"))
1030     (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
1031               new-name)
1032     (tar-alter-one-field 0
1033      (substring (concat encoded-new-name (make-string 99 0)) 0 99))))
1034
1035
1036 (defun tar-chmod-entry (new-mode)
1037   "Change the protection bits associated with this entry in the tar file.
1038 This does not modify the disk image; you must save the tar file itself
1039 for this to be permanent."
1040   (interactive (list (tar-parse-octal-integer-safe
1041                        (read-string "New protection (octal): "))))
1042   (tar-setf (tar-header-mode (tar-desc-tokens (tar-current-descriptor)))
1043             new-mode)
1044   (tar-alter-one-field tar-mode-offset
1045     (concat (substring (format "%6o" new-mode) 0 6) "\000 ")))
1046
1047
1048 (defun tar-alter-one-field (data-position new-data-string)
1049   (let* ((descriptor (tar-current-descriptor))
1050          (tokens (tar-desc-tokens descriptor)))
1051     (unwind-protect
1052         (save-excursion
1053           ;;
1054           ;; update the header-line.
1055           (beginning-of-line)
1056           (let ((p (point)))
1057             (forward-line 1)
1058             (delete-region p (point))
1059             (insert (tar-header-block-summarize tokens) "\n")
1060             (setq tar-header-offset (point-max)))
1061
1062           (widen)
1063           (let* ((start (+ (tar-desc-data-start descriptor)
1064                            (- tar-header-offset (point-min))
1065                            -512)))
1066             ;;
1067             ;; delete the old field and insert a new one.
1068             (goto-char (+ start data-position))
1069             (delete-region (point) (+ (point) (length new-data-string))) ; <--
1070
1071             ;; As new-data-string is unibyte, just inserting it will
1072             ;; make eight-bit chars to the corresponding multibyte
1073             ;; chars.  This avoid that conversion, i.e., eight-bit
1074             ;; chars are converted to multibyte form of eight-bit
1075             ;; chars.
1076             (insert (string-to-multibyte new-data-string))
1077             ;;
1078             ;; compute a new checksum and insert it.
1079             (let ((chk (tar-header-block-checksum
1080                         (buffer-substring start (+ start 512)))))
1081               (goto-char (+ start tar-chk-offset))
1082               (delete-region (point) (+ (point) 8))
1083               (insert (format "%6o" chk))
1084               (insert 0)
1085               (insert ? )
1086               (tar-setf (tar-header-checksum tokens) chk)
1087               ;;
1088               ;; ok, make sure we didn't botch it.
1089               (tar-header-block-check-checksum
1090                 (buffer-substring start (+ start 512))
1091                 chk (tar-header-name tokens))
1092               )))
1093       (narrow-to-region (point-min) tar-header-offset)
1094       (tar-next-line 0))))
1095
1096
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"
1101             (lsh hibits -2)
1102             (logior (lsh (logand 3 hibits) 1)
1103                     (if (> (logand lobits 32768) 0) 1 0))
1104             (logand 32767 lobits)
1105             )))
1106
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."
1111   (interactive)
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!"))
1116   (save-excursion
1117   (let ((subfile (current-buffer))
1118         (coding buffer-file-coding-system)
1119         (descriptor tar-superior-descriptor)
1120         subfile-size)
1121     (set-buffer tar-superior-buffer)
1122     (let* ((tokens (tar-desc-tokens descriptor))
1123            (start (tar-desc-data-start descriptor))
1124            (name (tar-header-name tokens))
1125            (size (tar-header-size tokens))
1126            (size-pad (ash (ash (+ size 511) -9) 9))
1127            (head (memq descriptor tar-parse-info))
1128            (following-descs (cdr head)))
1129       (if (not head)
1130         (error "Can't find this tar file entry in its parent tar file!"))
1131       (unwind-protect
1132        (save-excursion
1133         ;; delete the old data...
1134         (let* ((data-start (+ start (- tar-header-offset (point-min))))
1135                (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
1136           (narrow-to-region data-start data-end)
1137           (delete-region (point-min) (point-max))
1138           ;; insert the new data...
1139           (goto-char data-start)
1140           (save-excursion
1141             (set-buffer subfile)
1142             (save-restriction
1143               (widen)
1144               (encode-coding-region 1 (point-max) coding tar-superior-buffer)))
1145           (setq subfile-size (- (point-max) (point-min)))
1146           ;;
1147           ;; pad the new data out to a multiple of 512...
1148           (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
1149             (goto-char (point-max))
1150             (insert (make-string (- subfile-size-pad subfile-size) 0))
1151             ;;
1152             ;; update the data pointer of this and all following files...
1153             (tar-setf (tar-header-size tokens) subfile-size)
1154             (let ((difference (- subfile-size-pad size-pad)))
1155               (dolist (desc following-descs)
1156                 (tar-setf (tar-desc-data-start desc)
1157                           (+ (tar-desc-data-start desc) difference))))
1158             ;;
1159             ;; Update the size field in the header block.
1160             (widen)
1161             (let ((header-start (- data-start 512)))
1162               (goto-char (+ header-start tar-size-offset))
1163               (delete-region (point) (+ (point) 12))
1164               (insert (format "%11o" subfile-size))
1165               (insert ? )
1166               ;;
1167               ;; Maybe update the datestamp.
1168               (if (not tar-update-datestamp)
1169                   nil
1170                 (goto-char (+ header-start tar-time-offset))
1171                 (delete-region (point) (+ (point) 12))
1172                 (insert (tar-octal-time (current-time)))
1173                 (insert ? ))
1174               ;;
1175               ;; compute a new checksum and insert it.
1176               (let ((chk (tar-header-block-checksum
1177                           (buffer-substring header-start data-start))))
1178                 (goto-char (+ header-start tar-chk-offset))
1179                 (delete-region (point) (+ (point) 8))
1180                 (insert (format "%6o" chk))
1181                 (insert 0)
1182                 (insert ? )
1183                 (tar-setf (tar-header-checksum tokens) chk)))
1184             ;;
1185             ;; alter the descriptor-line...
1186             ;;
1187             (let ((position (- (length tar-parse-info) (length head))))
1188               (goto-char (point-min))
1189               (next-line position)
1190               (beginning-of-line)
1191               (let ((p (point))
1192                     after
1193                     (m (set-marker (make-marker) tar-header-offset)))
1194                 (forward-line 1)
1195                 (setq after (point))
1196                 ;; Insert the new text after the old, before deleting,
1197                 ;; to preserve the window start.
1198                 (let ((line (tar-header-block-summarize tokens t)))
1199                   (insert-before-markers line "\n"))
1200                 (delete-region p after)
1201                 (setq tar-header-offset (marker-position m)))
1202               )))
1203         ;; after doing the insertion, add any final padding that may be necessary.
1204         (tar-pad-to-blocksize))
1205        (narrow-to-region (point-min) tar-header-offset)))
1206     (set-buffer-modified-p t)   ; mark the tar file as modified
1207     (tar-next-line 0)
1208     (set-buffer subfile)
1209     (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
1210     (message "Saved into tar-buffer `%s'.  Be sure to save that buffer!"
1211              (buffer-name tar-superior-buffer))
1212     ;; Prevent basic-save-buffer from changing our coding-system.
1213     (setq last-coding-system-used buffer-file-coding-system)
1214     ;; Prevent ordinary saving from happening.
1215     t)))
1216
1217
1218 ;; When this function is called, it is sure that the buffer is unibyte.
1219 (defun tar-pad-to-blocksize ()
1220   "If we are being anal about tar file blocksizes, fix up the current buffer.
1221 Leaves the region wide."
1222   (if (null tar-anal-blocksize)
1223       nil
1224     (widen)
1225     (let* ((last-desc (nth (1- (length tar-parse-info)) tar-parse-info))
1226            (start (tar-desc-data-start last-desc))
1227            (tokens (tar-desc-tokens last-desc))
1228            (link-p (tar-header-link-type tokens))
1229            (size (if link-p 0 (tar-header-size tokens)))
1230            (data-end (+ start size))
1231            (bbytes (ash tar-anal-blocksize 9))
1232            (pad-to (+ bbytes (* bbytes (/ (- data-end (point-min)) bbytes))))
1233            (inhibit-read-only t) ; ##
1234            )
1235       ;; If the padding after the last data is too long, delete some;
1236       ;; else insert some until we are padded out to the right number of blocks.
1237       ;;
1238       (let ((goal-end (+ (or tar-header-offset 0) pad-to)))
1239         (if (> (point-max) goal-end)
1240             (delete-region goal-end (point-max))
1241           (goto-char (point-max))
1242           (insert (make-string (- goal-end (point-max)) ?\0)))))))
1243
1244
1245 ;; Used in write-file-hook to write tar-files out correctly.
1246 (defun tar-mode-write-file ()
1247   (unwind-protect
1248       (save-excursion
1249         (widen)
1250         ;; Doing this here confuses things - the region gets left too wide!
1251         ;; I suppose this is run in a context where changing the buffer is bad.
1252         ;; (tar-pad-to-blocksize)
1253         ;; tar-header-offset turns out to be null for files fetched with W3,
1254         ;; at least.
1255         (let ((coding-system-for-write 'no-conversion))
1256           (write-region (or tar-header-offset
1257                             (point-min))
1258                         (point-max)
1259                         buffer-file-name nil t))
1260         (tar-clear-modification-flags)
1261         (set-buffer-modified-p nil))
1262     (narrow-to-region (point-min) tar-header-offset))
1263   ;; Return t because we've written the file.
1264   t)
1265 \f
1266 (provide 'tar-mode)
1267
1268 ;; arch-tag: 8a585a4a-340e-42c2-89e7-d3b1013a4b78
1269 ;;; tar-mode.el ends here