summaryrefslogtreecommitdiff
path: root/lisp/jka-cmpr-hook.el
blob: 3de3b7daccc93b6a8bcd0a44d01c086007aa3b0d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
;;; jka-cmpr-hook.el --- preloaded code to enable jka-compr.el

;; Copyright (C) 1993, 1994, 1995, 1997, 1999, 2000, 2002, 2003,
;;   2004, 2005, 2006 Free Software Foundation, Inc.

;; Author: jka@ece.cmu.edu (Jay K. Adams)
;; Maintainer: FSF
;; Keywords: data

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; This file contains the  code to enable and disable Auto-Compression mode.
;; It is preloaded.  The guts of this mode are in jka-compr.el, which
;; is loaded only when you really try to uncompress something.

;;; Code:

(defgroup compression nil
  "Data compression utilities."
  :group 'data)

(defgroup jka-compr nil
  "jka-compr customization."
  :group 'compression)

;; I have this defined so that .Z files are assumed to be in unix
;; compress format; and .gz files, in gzip format, and .bz2 files in bzip fmt.
(defcustom jka-compr-compression-info-list
  ;;[regexp
  ;; compr-message  compr-prog  compr-args
  ;; uncomp-message uncomp-prog uncomp-args
  ;; can-append auto-mode-flag strip-extension-flag file-magic-bytes]
  '(["\\.Z\\(~\\|\\.~[0-9]+~\\)?\\'"
     "compressing"    "compress"     ("-c")
     "uncompressing"  "uncompress"   ("-c")
     nil t "\037\235"]
     ;; Formerly, these had an additional arg "-c", but that fails with
     ;; "Version 0.1pl2, 29-Aug-97." (RedHat 5.1 GNU/Linux) and
     ;; "Version 0.9.0b, 9-Sept-98".
    ["\\.bz2\\'"
     "bzip2ing"        "bzip2"         nil
     "bunzip2ing"      "bzip2"         ("-d")
     nil t "BZh"]
    ["\\.tbz\\'"
     "bzip2ing"        "bzip2"         nil
     "bunzip2ing"      "bzip2"         ("-d")
     nil nil "BZh"]
    ["\\.tgz\\'"
     "compressing"        "gzip"         ("-c" "-q")
     "uncompressing"      "gzip"         ("-c" "-q" "-d")
     t nil "\037\213"]
    ["\\.g?z\\(~\\|\\.~[0-9]+~\\)?\\'"
     "compressing"        "gzip"         ("-c" "-q")
     "uncompressing"      "gzip"         ("-c" "-q" "-d")
     t t "\037\213"]
    ;; dzip is gzip with random access.  Its compression program can't
    ;; read/write stdin/out, so .dz files can only be viewed without
    ;; saving, having their contents decompressed with gzip.
    ["\\.dz\\'"
     nil              nil            nil
     "uncompressing"      "gzip"         ("-c" "-q" "-d")
     nil t "\037\213"])

  "List of vectors that describe available compression techniques.
Each element, which describes a compression technique, is a vector of
the form [REGEXP COMPRESS-MSG COMPRESS-PROGRAM COMPRESS-ARGS
UNCOMPRESS-MSG UNCOMPRESS-PROGRAM UNCOMPRESS-ARGS
APPEND-FLAG STRIP-EXTENSION-FLAG FILE-MAGIC-CHARS], where:

   regexp                is a regexp that matches filenames that are
                         compressed with this format

   compress-msg          is the message to issue to the user when doing this
                         type of compression (nil means no message)

   compress-program      is a program that performs this compression
                         (nil means visit file in read-only mode)

   compress-args         is a list of args to pass to the compress program

   uncompress-msg        is the message to issue to the user when doing this
                         type of uncompression (nil means no message)

   uncompress-program    is a program that performs this compression

   uncompress-args       is a list of args to pass to the uncompress program

   append-flag           is non-nil if this compression technique can be
                         appended

   strip-extension-flag  non-nil means strip the regexp from file names
                         before attempting to set the mode.

   file-magic-chars      is a string of characters that you would find
			 at the beginning of a file compressed in this way.

Because of the way `call-process' is defined, discarding the stderr output of
a program adds the overhead of starting a shell each time the program is
invoked."
  :type '(repeat (vector regexp
			 (choice :tag "Compress Message"
				 (string :format "%v")
				 (const :tag "No Message" nil))
			 (choice :tag "Compress Program"
				 (string)
				 (const :tag "None" nil))
			 (repeat :tag "Compress Arguments" string)
			 (choice :tag "Uncompress Message"
				 (string :format "%v")
				 (const :tag "No Message" nil))
			 (choice :tag "Uncompress Program"
				 (string)
				 (const :tag "None" nil))
			 (repeat :tag "Uncompress Arguments" string)
			 (boolean :tag "Append")
			 (boolean :tag "Strip Extension")
			 (string :tag "Magic Bytes")))
  :group 'jka-compr)

(defcustom jka-compr-mode-alist-additions
  (list (cons "\\.tgz\\'" 'tar-mode) (cons "\\.tbz\\'" 'tar-mode))
  "A list of pairs to add to `auto-mode-alist' when jka-compr is installed."
  :type '(repeat (cons string symbol))
  :group 'jka-compr)

(defcustom jka-compr-load-suffixes '(".gz")
  "List of suffixes to try when loading files."
  :type '(repeat string)
  :group 'jka-compr)

;; List of all the elements we actually added to file-coding-system-alist.
(defvar jka-compr-added-to-file-coding-system-alist nil)

(defvar jka-compr-file-name-handler-entry
  nil
  "The entry in `file-name-handler-alist' used by the jka-compr I/O functions.")

(defun jka-compr-build-file-regexp ()
  (mapconcat
   'jka-compr-info-regexp
   jka-compr-compression-info-list
   "\\|"))

;; Functions for accessing the return value of jka-compr-get-compression-info
(defun jka-compr-info-regexp               (info)  (aref info 0))
(defun jka-compr-info-compress-message     (info)  (aref info 1))
(defun jka-compr-info-compress-program     (info)  (aref info 2))
(defun jka-compr-info-compress-args        (info)  (aref info 3))
(defun jka-compr-info-uncompress-message   (info)  (aref info 4))
(defun jka-compr-info-uncompress-program   (info)  (aref info 5))
(defun jka-compr-info-uncompress-args      (info)  (aref info 6))
(defun jka-compr-info-can-append           (info)  (aref info 7))
(defun jka-compr-info-strip-extension      (info)  (aref info 8))
(defun jka-compr-info-file-magic-bytes     (info)  (aref info 9))


(defun jka-compr-get-compression-info (filename)
  "Return information about the compression scheme of FILENAME.
The determination as to which compression scheme, if any, to use is
based on the filename itself and `jka-compr-compression-info-list'."
  (catch 'compression-info
    (let ((case-fold-search nil))
      (mapcar
       (function (lambda (x)
		   (and (string-match (jka-compr-info-regexp x) filename)
			(throw 'compression-info x))))
       jka-compr-compression-info-list)
      nil)))

(defun jka-compr-install ()
  "Install jka-compr.
This adds entries to `file-name-handler-alist' and `auto-mode-alist'
and `inhibit-first-line-modes-suffixes'."

  (setq jka-compr-file-name-handler-entry
	(cons (jka-compr-build-file-regexp) 'jka-compr-handler))

  (push jka-compr-file-name-handler-entry file-name-handler-alist)

  (dolist (x jka-compr-compression-info-list)
    ;; Don't do multibyte encoding on the compressed files.
    (let ((elt (cons (jka-compr-info-regexp x)
                     '(no-conversion . no-conversion))))
      (push elt file-coding-system-alist)
      (push elt jka-compr-added-to-file-coding-system-alist))

    (and (jka-compr-info-strip-extension x)
         ;; Make entries in auto-mode-alist so that modes
         ;; are chosen right according to the file names
         ;; sans `.gz'.
         (push (list (jka-compr-info-regexp x) nil 'jka-compr) auto-mode-alist)
         ;; Also add these regexps to
         ;; inhibit-first-line-modes-suffixes, so that a
         ;; -*- line in the first file of a compressed tar
         ;; file doesn't override tar-mode.
         (push (jka-compr-info-regexp x)
               inhibit-first-line-modes-suffixes)))
  (setq auto-mode-alist
	(append auto-mode-alist jka-compr-mode-alist-additions))

  ;; Make sure that (load "foo") will find /bla/foo.el.gz.
  (setq load-suffixes
	(apply 'append
	       (append (mapcar (lambda (suffix)
                               (cons suffix
                                     (mapcar (lambda (ext) (concat suffix ext))
                                             jka-compr-load-suffixes)))
                             load-suffixes)
                       (list jka-compr-load-suffixes)))))


(defun jka-compr-installed-p ()
  "Return non-nil if jka-compr is installed.
The return value is the entry in `file-name-handler-alist' for jka-compr."

  (let ((fnha file-name-handler-alist)
	(installed nil))

    (while (and fnha (not installed))
     (and (eq (cdr (car fnha)) 'jka-compr-handler)
	   (setq installed (car fnha)))
      (setq fnha (cdr fnha)))

    installed))

(define-minor-mode auto-compression-mode
  "Toggle automatic file compression and uncompression.
With prefix argument ARG, turn auto compression on if positive, else off.
Returns the new status of auto compression (non-nil means on)."
  :global t :init-value t :group 'jka-compr :version "22.1"
  (let* ((installed (jka-compr-installed-p))
	 (flag auto-compression-mode))
    (cond
     ((and flag installed) t)		; already installed
     ((and (not flag) (not installed)) nil) ; already not installed
     (flag (jka-compr-install))
     (t (jka-compr-uninstall)))))

(defmacro with-auto-compression-mode (&rest body)
  "Evalute BODY with automatic file compression and uncompression enabled."
  (let ((already-installed (make-symbol "already-installed")))
    `(let ((,already-installed (jka-compr-installed-p)))
       (unwind-protect
	   (progn
	     (unless ,already-installed
	       (jka-compr-install))
	     ,@body)
	 (unless ,already-installed
	   (jka-compr-uninstall))))))
(put 'with-auto-compression-mode 'lisp-indent-function 0)


;; This is what we need to know about jka-compr-handler
;; in order to decide when to call it.

(put 'jka-compr-handler 'safe-magic t)
(put 'jka-compr-handler 'operations '(byte-compiler-base-file-name
				      write-region insert-file-contents
				      file-local-copy load))

;; Turn on the mode.
(when auto-compression-mode (auto-compression-mode 1))

(provide 'jka-cmpr-hook)

;; arch-tag: 4bd73429-f400-45fe-a065-270a113e31a8
;;; jka-cmpr-hook.el ends here