1 ;;; jka-compr.el --- reading/writing/loading compressed files
3 ;;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
5 ;; Author: jka@ece.cmu.edu (Jay K. Adams)
10 ;;; This package implements low-level support for reading, writing,
11 ;;; and loading compressed files. It hooks into the low-level file
12 ;;; I/O functions (including write-region and insert-file-contents) so
13 ;;; that they automatically compress or uncompress a file if the file
14 ;;; appears to need it (based on the extension of the file name).
15 ;;; Packages like Rmail, VM, GNUS, and Info should be able to work
16 ;;; with compressed files without modification.
21 ;;; To use jka-compr, simply load this package, and edit as usual.
22 ;;; Its operation should be transparent to the user (except for
23 ;;; messages appearing when a file is being compressed or
26 ;;; The variable, jka-compr-compression-info-list can be used to
27 ;;; customize jka-compr to work with other compression programs.
28 ;;; The default value of this variable allows jka-compr to work with
29 ;;; Unix compress and gzip.
31 ;;; If you are concerned about the stderr output of gzip and other
32 ;;; compression/decompression programs showing up in your buffers, you
33 ;;; should set the discard-error flag in the compression-info-list.
34 ;;; This will cause the stderr of all programs to be discarded.
35 ;;; However, it also causes emacs to call compression/uncompression
36 ;;; programs through a shell (which is specified by jka-compr-shell).
37 ;;; This may be a drag if, on your system, starting up a shell is
40 ;;; If you don't want messages about compressing and decompressing
41 ;;; to show up in the echo area, you can set the compress-name and
42 ;;; decompress-name fields of the jka-compr-compression-info-list to
46 ;;; APPLICATION NOTES:
49 ;;; jka-compr can coexist with crpyt++ if you take all the decompression
50 ;;; entries out of the crypt-encoding-list. Clearly problems will arise if
51 ;;; you have two programs trying to compress/decompress files. jka-compr
52 ;;; will not "work with" crypt++ in the following sense: you won't be able to
53 ;;; decode encrypted compressed files--that is, files that have been
54 ;;; compressed then encrypted (in that order). Theoretically, crypt++ and
55 ;;; jka-compr could properly handle a file that has been encrypted then
56 ;;; compressed, but there is little point in trying to compress an encrypted
63 ;;; jka-compr is a V19 adaptation of jka-compr for V18 of Emacs. Many people
64 ;;; have made helpful suggestions, reported bugs, and even fixed bugs in
65 ;;; jka-compr. I recall the following people as being particularly helpful.
74 ;;; Andy Norman's ange-ftp was the inspiration for the original jka-compr for
75 ;;; Version 18 of Emacs.
77 ;;; After I had made progress on the original jka-compr for V18, I learned of a
78 ;;; package written by Kazushi Jam Marukawa, called jam-zcat, that did exactly
79 ;;; what I was trying to do. I looked over the jam-zcat source code and
80 ;;; probably got some ideas from it.
85 (defvar jka-compr-shell
"sh"
86 "*Shell to be used for calling compression programs.
87 The value of this variable only matters if you want to discard the
88 stderr of a compression/decompression program (see the documentation
89 for `jka-compr-compression-info-list').")
92 (defvar jka-compr-use-shell t
)
95 ;;; I have this defined so that .Z files are assumed to be in unix
96 ;;; compress format; and .gz files, in gzip format.
97 (defvar jka-compr-compression-info-list
99 ;; compr-message compr-prog compr-args
100 ;; uncomp-message uncomp-prog uncomp-args
101 ;; can-append auto-mode-flag]
102 '(["\\.Z\\(~\\|\\.~[0-9]+~\\)?\\'"
103 "compressing" "compress" ("-c")
104 "uncompressing" "uncompress" ("-c")
107 "zipping" "gzip" ("-c" "-q")
108 "unzipping" "gzip" ("-c" "-q" "-d")
110 ["\\.gz\\(~\\|\\.~[0-9]+~\\)?\\'"
111 "zipping" "gzip" ("-c" "-q")
112 "unzipping" "gzip" ("-c" "-q" "-d")
115 "List of vectors that describe available compression techniques.
116 Each element, which describes a compression technique, is a vector of
117 the form [REGEXP COMPRESS-MSG COMPRESS-PROGRAM COMPRESS-ARGS
118 UNCOMPRESS-MSG UNCOMPRESS-PROGRAM UNCOMPRESS-ARGS
119 APPEND-FLAG EXTENSION], where:
121 regexp is a regexp that matches filenames that are
122 compressed with this format
124 compress-msg is the message to issue to the user when doing this
125 type of compression (nil means no message)
127 compress-program is a program that performs this compression
129 compress-args is a list of args to pass to the compress program
131 uncompress-msg is the message to issue to the user when doing this
132 type of uncompression (nil means no message)
134 uncompress-program is a program that performs this compression
136 uncompress-args is a list of args to pass to the uncompress program
138 append-flag is non-nil if this compression technique can be
141 auto-mode flag non-nil means strip the regexp from file names
142 before attempting to set the mode.
144 Because of the way `call-process' is defined, discarding the stderr output of
145 a program adds the overhead of starting a shell each time the program is
148 (defvar jka-compr-mode-alist-additions
149 (list (cons "\\.tgz\\'" 'tar-mode
))
150 "A list of pairs to add to auto-mode-alist when jka-compr is installed.")
152 (defvar jka-compr-file-name-handler-entry
154 "The entry in `file-name-handler-alist' used by the jka-compr I/O functions.")
156 ;;; Functions for accessing the return value of jka-get-compression-info
157 (defun jka-compr-info-regexp (info) (aref info
0))
158 (defun jka-compr-info-compress-message (info) (aref info
1))
159 (defun jka-compr-info-compress-program (info) (aref info
2))
160 (defun jka-compr-info-compress-args (info) (aref info
3))
161 (defun jka-compr-info-uncompress-message (info) (aref info
4))
162 (defun jka-compr-info-uncompress-program (info) (aref info
5))
163 (defun jka-compr-info-uncompress-args (info) (aref info
6))
164 (defun jka-compr-info-can-append (info) (aref info
7))
165 (defun jka-compr-info-strip-extension (info) (aref info
8))
168 (defun jka-compr-get-compression-info (filename)
169 "Return information about the compression scheme of FILENAME.
170 The determination as to which compression scheme, if any, to use is
171 based on the filename itself and `jka-compr-compression-info-list'."
172 (catch 'compression-info
173 (let ((case-fold-search nil
))
175 (function (lambda (x)
176 (and (string-match (jka-compr-info-regexp x
) filename
)
177 (throw 'compression-info x
))))
178 jka-compr-compression-info-list
)
182 (put 'compression-error
'error-conditions
'(compression-error file-error error
))
185 (defvar jka-compr-acceptable-retval-list
'(0 2 141))
188 (defun jka-compr-error (prog args infile message
&optional errfile
)
190 (let ((errbuf (get-buffer-create " *jka-compr-error*"))
191 (curbuf (current-buffer)))
193 (widen) (erase-buffer)
194 (insert (format "Error while executing \"%s %s < %s\"\n\n"
196 (mapconcat 'identity args
" ")
200 (insert-file-contents errfile
))
203 (display-buffer errbuf
))
205 (signal 'compression-error
(list "Opening input file" (format "error %s" message
) infile
)))
208 (defvar jka-compr-dd-program
212 (defvar jka-compr-dd-blocksize
256)
215 (defun jka-compr-partial-uncompress (prog message args infile beg len
)
216 "Call program PROG with ARGS args taking input from INFILE.
217 Fourth and fifth args, BEG and LEN, specify which part of the output
218 to keep: LEN chars starting BEG chars from the beginning."
219 (let* ((skip (/ beg jka-compr-dd-blocksize
))
220 (prefix (- beg
(* skip jka-compr-dd-blocksize
)))
221 (count (and len
(1+ (/ (+ len prefix
) jka-compr-dd-blocksize
))))
223 (err-file (jka-compr-make-temp-name))
224 (run-string (format "%s %s 2> %s | %s bs=%d skip=%d %s 2> /dev/null"
226 (mapconcat 'identity args
" ")
229 jka-compr-dd-blocksize
231 ;; dd seems to be unreliable about
232 ;; providing the last block. So, always
233 ;; read one more than you think you need.
234 (if count
(concat "count=" (1+ count
)) ""))))
237 (or (memq (call-process jka-compr-shell
240 jka-compr-acceptable-retval-list
)
242 (jka-compr-error prog args infile message err-file
))
244 (jka-compr-delete-temp-file err-file
))
246 ;; Delete the stuff after what we want, if there is any.
249 (< (+ start prefix len
) (point))
250 (delete-region (+ start prefix len
) (point)))
252 ;; Delete the stuff before what we want.
253 (delete-region start
(+ start prefix
))))
256 (defun jka-compr-call-process (prog message infile output temp args
)
257 (if jka-compr-use-shell
259 (let ((err-file (jka-compr-make-temp-name)))
264 (call-process jka-compr-shell infile
265 (if (stringp output
) nil output
)
268 (format "%s %s 2> %s %s"
270 (mapconcat 'identity args
" ")
275 jka-compr-acceptable-retval-list
)
277 (jka-compr-error prog args infile message err-file
))
279 (jka-compr-delete-temp-file err-file
)))
285 (if (stringp output
) temp output
)
288 (jka-compr-error prog args infile message
))
290 (and (stringp output
)
291 (let ((cbuf (current-buffer)))
293 (write-region (point-min) (point-max) output
)
295 (set-buffer cbuf
)))))
298 ;;; Support for temp files. Much of this was inspired if not lifted
301 (defvar jka-compr-temp-name-template
303 "Prefix added to all temp files created by jka-compr.
304 There should be no more than seven characters after the final `/'")
306 (defvar jka-compr-temp-name-table
(make-vector 31 nil
))
308 (defun jka-compr-make-temp-name (&optional local-copy
)
309 "This routine will return the name of a new file."
312 (template (concat jka-compr-temp-name-template
"aa"))
313 (lastpos (1- (length template
)))
319 (aset template lastpos lastchar
)
320 (setq file
(concat (make-temp-name template
) "#"))
321 (setq entry
(intern file jka-compr-temp-name-table
))
322 (if (or (get entry
'active
)
323 (file-exists-p file
))
326 (setq lastchar
(1+ lastchar
))
329 (setq prevchar
(1+ prevchar
))
332 (error "Can't allocate temp file.")
333 (aset template
(1- lastpos
) prevchar
)))))
335 (put entry
'active
(not local-copy
))
336 (setq not-done nil
)))
341 (defun jka-compr-delete-temp-file (temp)
343 (put (intern temp jka-compr-temp-name-table
)
351 (defun jka-compr-write-region (start end file
&optional append visit
)
352 (let* ((filename (expand-file-name file
))
353 (visit-file (if (stringp visit
) (expand-file-name visit
) filename
))
354 (info (jka-compr-get-compression-info visit-file
)))
358 (let ((can-append (jka-compr-info-can-append info
))
359 (compress-program (jka-compr-info-compress-program info
))
360 (compress-message (jka-compr-info-compress-message info
))
361 (uncompress-program (jka-compr-info-uncompress-program info
))
362 (uncompress-message (jka-compr-info-uncompress-message info
))
363 (compress-args (jka-compr-info-compress-args info
))
364 (uncompress-args (jka-compr-info-uncompress-args info
))
365 (base-name (file-name-nondirectory visit-file
))
366 temp-file cbuf temp-buffer
)
368 (setq cbuf
(current-buffer)
369 temp-buffer
(get-buffer-create " *jka-compr-wr-temp*"))
370 (set-buffer temp-buffer
)
371 (widen) (erase-buffer)
376 (file-exists-p filename
))
378 (let* ((local-copy (file-local-copy filename
))
379 (local-file (or local-copy filename
)))
381 (setq temp-file local-file
))
383 (setq temp-file
(jka-compr-make-temp-name)))
387 (message "%s %s..." compress-message base-name
))
389 (jka-compr-run-real-handler 'write-region
390 (list start end temp-file t
'dont
))
392 (jka-compr-call-process compress-program
393 (concat compress-message
400 (set-buffer temp-buffer
)
401 (jka-compr-run-real-handler 'write-region
402 (list (point-min) (point-max)
404 (and append can-append
) 'dont
))
408 (jka-compr-delete-temp-file temp-file
)
412 (message "%s %s...done" compress-message base-name
))
416 (setq buffer-file-name filename
)
417 (set-visited-file-modtime))
419 (setq buffer-file-name visit
)
420 (let ((buffer-file-name filename
))
421 (set-visited-file-modtime))))
423 (and (or (eq visit t
)
426 (message "Wrote %s" visit-file
))
430 (jka-compr-run-real-handler 'write-region
431 (list start end filename append visit
)))))
434 (defun jka-compr-insert-file-contents (file &optional visit beg end replace
)
435 (barf-if-buffer-read-only)
439 (error "Attempt to visit less than an entire file"))
441 (let* ((filename (expand-file-name file
))
442 (info (jka-compr-get-compression-info filename
)))
446 (let ((uncompress-message (jka-compr-info-uncompress-message info
))
447 (uncompress-program (jka-compr-info-uncompress-program info
))
448 (uncompress-args (jka-compr-info-uncompress-args info
))
449 (base-name (file-name-nondirectory filename
))
452 (jka-compr-run-real-handler 'file-local-copy
(list filename
)))
456 (setq local-file
(or local-copy filename
))
460 (setq buffer-file-name filename
))
462 (unwind-protect ; to make sure local-copy gets deleted
468 (message "%s %s..." uncompress-message base-name
))
470 (condition-case error-code
474 (goto-char (point-min)))
477 (jka-compr-partial-uncompress uncompress-program
478 (concat uncompress-message
486 ;; If visiting, bind off buffer-file-name so that
487 ;; file-locking will not ask whether we should
488 ;; really edit the buffer.
489 (let ((buffer-file-name
490 (if visit nil buffer-file-name
)))
491 (jka-compr-call-process uncompress-program
492 (concat uncompress-message
498 (setq size
(- (point) start
))
500 (let* ((del-beg (point))
501 (del-end (+ del-beg size
)))
502 (delete-region del-beg
503 (min del-end
(point-max)))))
506 (if (and (eq (car error-code
) 'file-error
)
507 (eq (nth 3 error-code
) local-file
))
509 (setq notfound error-code
)
511 (cons "Opening input file"
512 (nthcdr 2 error-code
))))
513 (signal (car error-code
) (cdr error-code
))))))
517 (file-exists-p local-copy
)
518 (delete-file local-copy
)))
524 (setq buffer-file-name filename
)
525 (set-visited-file-modtime)))
529 (message "%s %s...done" uncompress-message base-name
))
535 (cons "Opening input file" (nth 2 notfound
))))
537 ;; Run the functions that insert-file-contents would.
538 (let ((p after-insert-file-functions
)
541 (setq insval
(funcall (car p
) size
))
544 (or (integerp insval
)
545 (signal 'wrong-type-argument
546 (list 'integerp insval
)))
550 (list filename size
))
552 (jka-compr-run-real-handler 'insert-file-contents
553 (list file visit beg end replace
)))))
556 (defun jka-compr-file-local-copy (file)
557 (let* ((filename (expand-file-name file
))
558 (info (jka-compr-get-compression-info filename
)))
562 (let ((uncompress-message (jka-compr-info-uncompress-message info
))
563 (uncompress-program (jka-compr-info-uncompress-program info
))
564 (uncompress-args (jka-compr-info-uncompress-args info
))
565 (base-name (file-name-nondirectory filename
))
567 (jka-compr-run-real-handler 'file-local-copy
(list filename
)))
568 (temp-file (jka-compr-make-temp-name t
))
569 (temp-buffer (get-buffer-create " *jka-compr-flc-temp*"))
571 (cbuf (current-buffer))
574 (setq local-file
(or local-copy filename
))
582 (message "%s %s..." uncompress-message base-name
))
584 (set-buffer temp-buffer
)
586 (jka-compr-call-process uncompress-program
587 (concat uncompress-message
596 (message "%s %s...done" uncompress-message base-name
))
599 (point-min) (point-max) temp-file nil
'dont
))
603 (file-exists-p local-copy
)
604 (delete-file local-copy
))
607 (kill-buffer temp-buffer
))
611 (jka-compr-run-real-handler 'file-local-copy
(list filename
)))))
614 ;;; Support for loading compressed files.
615 (defun jka-compr-load (file &optional noerror nomessage nosuffix
)
616 "Documented as original."
618 (let* ((local-copy (jka-compr-file-local-copy file
))
619 (load-file (or local-copy file
)))
623 (let (inhibit-file-name-operation
624 inhibit-file-name-handlers
)
626 (message "Loading %s..." file
))
628 (let ((load-force-doc-strings t
))
629 (load load-file noerror t t
))
632 (message "Loading %s...done." file
)))
634 (jka-compr-delete-temp-file local-copy
))
638 (defun jka-compr-byte-compiler-base-file-name (file)
639 (let ((info (jka-compr-get-compression-info file
)))
640 (if (and info
(jka-compr-info-strip-extension info
))
642 (substring file
0 (string-match (jka-compr-info-regexp info
) file
)))
645 (put 'write-region
'jka-compr
'jka-compr-write-region
)
646 (put 'insert-file-contents
'jka-compr
'jka-compr-insert-file-contents
)
647 (put 'file-local-copy
'jka-compr
'jka-compr-file-local-copy
)
648 (put 'load
'jka-compr
'jka-compr-load
)
649 (put 'byte-compiler-base-file-name
'jka-compr
650 'jka-compr-byte-compiler-base-file-name
)
652 (defun jka-compr-handler (operation &rest args
)
654 (let ((jka-op (get operation
'jka-compr
)))
657 (jka-compr-run-real-handler operation args
)))))
659 ;; If we are given an operation that we don't handle,
660 ;; call the Emacs primitive for that operation,
661 ;; and manipulate the inhibit variables
662 ;; to prevent the primitive from calling our handler again.
663 (defun jka-compr-run-real-handler (operation args
)
664 (let ((inhibit-file-name-handlers
665 (cons 'jka-compr-handler
666 (and (eq inhibit-file-name-operation operation
)
667 inhibit-file-name-handlers
)))
668 (inhibit-file-name-operation operation
))
669 (apply operation args
)))
672 (defun auto-compression-mode (arg)
673 "Toggle automatic file compression and uncompression.
674 With prefix argument ARG, turn auto compression on if positive, else off.
675 Returns the new status of auto compression (non-nil means on)."
677 (let* ((installed (jka-compr-installed-p))
680 (or (eq arg t
) (listp arg
) (and (integerp arg
) (> arg
0))))))
683 ((and flag installed
) t
) ; already installed
685 ((and (not flag
) (not installed
)) nil
) ; already not installed
691 (jka-compr-uninstall)))
696 (message "Automatic file (de)compression is now ON.")
697 (message "Automatic file (de)compression is now OFF.")))
700 (defalias 'toggle-auto-compression
'auto-compression-mode
)
702 (defun jka-compr-build-file-regexp ()
706 'jka-compr-info-regexp
707 jka-compr-compression-info-list
712 (defun jka-compr-install ()
714 This adds entries to `file-name-handler-alist' and `auto-mode-alist'
715 and `inhibit-first-line-modes-suffixes'."
717 (setq jka-compr-file-name-handler-entry
718 (cons (jka-compr-build-file-regexp) 'jka-compr-handler
))
720 (setq file-name-handler-alist
(cons jka-compr-file-name-handler-entry
721 file-name-handler-alist
))
724 (function (lambda (x)
725 (and (jka-compr-info-strip-extension x
)
726 ;; Make entries in auto-mode-alist so that modes
727 ;; are chosen right according to the file names
729 (setq auto-mode-alist
730 (cons (list (jka-compr-info-regexp x
)
733 ;; Also add these regexps to
734 ;; inhibit-first-line-modes-suffixes, so that a
735 ;; -*- line in the first file of a compressed tar
736 ;; file doesn't override tar-mode.
737 (setq inhibit-first-line-modes-suffixes
738 (cons (jka-compr-info-regexp x
)
739 inhibit-first-line-modes-suffixes
)))))
740 jka-compr-compression-info-list
)
741 (setq auto-mode-alist
742 (append auto-mode-alist jka-compr-mode-alist-additions
)))
745 (defun jka-compr-uninstall ()
746 "Uninstall jka-compr.
747 This removes the entries in `file-name-handler-alist' and `auto-mode-alist'
748 and `inhibit-first-line-modes-suffixes' that were added
749 by `jka-compr-installed'."
750 ;; Delete from inhibit-first-line-modes-suffixes
751 ;; what jka-compr-install added.
753 (function (lambda (x)
754 (and (jka-compr-info-strip-extension x
)
755 (setq inhibit-first-line-modes-suffixes
756 (delete (jka-compr-info-regexp x
)
757 inhibit-first-line-modes-suffixes
)))))
758 jka-compr-compression-info-list
)
760 (let* ((fnha (cons nil file-name-handler-alist
))
764 (if (eq (cdr (car (cdr last
))) 'jka-compr-handler
)
765 (setcdr last
(cdr (cdr last
)))
766 (setq last
(cdr last
))))
768 (setq file-name-handler-alist
(cdr fnha
)))
770 (let* ((ama (cons nil auto-mode-alist
))
775 (setq entry
(car (cdr last
)))
776 (if (or (member entry jka-compr-mode-alist-additions
)
777 (and (consp (cdr entry
))
778 (eq (nth 2 entry
) 'jka-compr
)))
779 (setcdr last
(cdr (cdr last
)))
780 (setq last
(cdr last
))))
782 (setq auto-mode-alist
(cdr ama
))))
785 (defun jka-compr-installed-p ()
786 "Return non-nil if jka-compr is installed.
787 The return value is the entry in `file-name-handler-alist' for jka-compr."
789 (let ((fnha file-name-handler-alist
)
792 (while (and fnha
(not installed
))
793 (and (eq (cdr (car fnha
)) 'jka-compr-handler
)
794 (setq installed
(car fnha
)))
795 (setq fnha
(cdr fnha
)))
800 ;;; Add the file I/O hook if it does not already exist.
801 ;;; Make sure that jka-compr-file-name-handler-entry is eq to the
802 ;;; entry for jka-compr in file-name-handler-alist.
803 (and (jka-compr-installed-p)
804 (jka-compr-uninstall))
811 ;; jka-compr.el ends here.