files.el 125 KB
Newer Older
Eric S. Raymond's avatar
Eric S. Raymond committed
1 2
;;; files.el --- file input and output commands for Emacs

Richard M. Stallman's avatar
Richard M. Stallman committed
3
;; Copyright (C) 1985, 86, 87, 92, 93,
4
;;		 94, 95, 96, 97, 1998 Free Software Foundation, Inc.
Roland McGrath's avatar
Roland McGrath committed
5

Eric S. Raymond's avatar
Eric S. Raymond committed
6 7
;; Maintainer: FSF

Roland McGrath's avatar
Roland McGrath committed
8 9 10 11
;; 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
Eric S. Raymond's avatar
Eric S. Raymond committed
12
;; the Free Software Foundation; either version 2, or (at your option)
Roland McGrath's avatar
Roland McGrath committed
13 14 15 16 17 18 19 20
;; 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
21 22 23
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
Roland McGrath's avatar
Roland McGrath committed
24

25 26 27 28 29 30
;;; Commentary:

;; Defines most of Emacs's file- and directory-handling functions,
;; including basic file visiting, backup generation, link handling,
;; ITS-id version control, load- and write-hook handling, and the like.

Eric S. Raymond's avatar
Eric S. Raymond committed
31 32
;;; Code:

33 34
(defgroup backup nil
  "Backups of edited data files."
35
  :group 'files)
Roland McGrath's avatar
Roland McGrath committed
36

37
(defgroup find-file nil
38 39
  "Finding files."
  :group 'files)
40 41 42


(defcustom delete-auto-save-files t
43 44 45 46
  "*Non-nil means delete auto-save file when a buffer is saved or killed.

Note that auto-save file will not be deleted if the buffer is killed
when it has unsaved changes."
47 48 49 50
  :type 'boolean
  :group 'auto-save)

(defcustom directory-abbrev-alist
Roland McGrath's avatar
Roland McGrath committed
51 52 53 54 55 56 57
  nil
  "*Alist of abbreviations for file directories.
A list of elements of the form (FROM . TO), each meaning to replace
FROM with TO when it appears in a directory name.  This replacement is
done when setting up the default directory of a newly visited file.
*Every* FROM string should start with `^'.

58 59 60
Do not use `~' in the TO strings.
They should be ordinary absolute directory names.

Roland McGrath's avatar
Roland McGrath committed
61 62
Use this feature when you have directories which you normally refer to
via absolute symbolic links.  Make TO the name of the link, and FROM
63 64 65 66 67 68 69
the name it is linked to."
  :type '(repeat (cons :format "%v"
		       :value ("" . "")
		       (regexp :tag "From")
		       (regexp :tag "To")))
  :group 'abbrev
  :group 'find-file)
Roland McGrath's avatar
Roland McGrath committed
70 71

;;; Turn off backup files on VMS since it has version numbers.
72
(defcustom make-backup-files (not (eq system-type 'vax-vms))
73
  "*Non-nil means make a backup of a file the first time it is saved.
Roland McGrath's avatar
Roland McGrath committed
74 75 76 77 78 79 80 81 82 83 84 85 86 87
This can be done by renaming the file or by copying.

Renaming means that Emacs renames the existing file so that it is a
backup file, then writes the buffer into a new file.  Any other names
that the old file had will now refer to the backup file.  The new file
is owned by you and its group is defaulted.

Copying means that Emacs copies the existing file into the backup
file, then writes the buffer on top of the existing file.  Any other
names that the old file had will now refer to the new (edited) file.
The file's owner and group are unchanged.

The choice of renaming or copying is controlled by the variables
`backup-by-copying', `backup-by-copying-when-linked' and
88 89 90
`backup-by-copying-when-mismatch'.  See also `backup-inhibited'."
  :type 'boolean
  :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
91 92 93 94

;; Do this so that local variables based on the file name
;; are not overridden by the major mode.
(defvar backup-inhibited nil
95 96 97
  "Non-nil means don't make a backup, regardless of the other parameters.
This variable is intended for use by making it local to a buffer.
But it is local only if you make it local.")
Roland McGrath's avatar
Roland McGrath committed
98 99
(put 'backup-inhibited 'permanent-local t)

100
(defcustom backup-by-copying nil
Roland McGrath's avatar
Roland McGrath committed
101
 "*Non-nil means always use copying to create backup files.
102 103 104
See documentation of variable `make-backup-files'."
 :type 'boolean
 :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
105

106
(defcustom backup-by-copying-when-linked nil
Roland McGrath's avatar
Roland McGrath committed
107 108
 "*Non-nil means use copying to create backups for files with multiple names.
This causes the alternate names to refer to the latest version as edited.
109 110 111
This variable is relevant only if `backup-by-copying' is nil."
 :type 'boolean
 :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
112

113
(defcustom backup-by-copying-when-mismatch nil
Roland McGrath's avatar
Roland McGrath committed
114 115 116 117 118
  "*Non-nil means create backups by copying if this preserves owner or group.
Renaming may still be used (subject to control of other variables)
when it would not result in changing the owner or group of the file;
that is, for files which are owned by you and whose group matches
the default for a new file created there by you.
119 120 121
This variable is relevant only if `backup-by-copying' is nil."
  :type 'boolean
  :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
122 123 124 125 126 127 128 129

(defvar backup-enable-predicate
  '(lambda (name)
     (or (< (length name) 5)
	 (not (string-equal "/tmp/" (substring name 0 5)))))
  "Predicate that looks at a file name and decides whether to make backups.
Called with an absolute file name as argument, it returns t to enable backup.")

130
(defcustom buffer-offer-save nil
Roland McGrath's avatar
Roland McGrath committed
131 132
  "*Non-nil in a buffer means offer to save the buffer on exit
even if the buffer is not visiting a file.
133 134 135
Automatically local in all buffers."
  :type 'boolean
  :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
136 137
(make-variable-buffer-local 'buffer-offer-save)

138
(defcustom find-file-existing-other-name t
139 140
  "*Non-nil means find a file under alternative names, in existing buffers.
This means if any existing buffer is visiting the file you want
141 142 143
under another name, you get the existing buffer instead of a new buffer."
  :type 'boolean
  :group 'find-file)
144

145
(defcustom find-file-visit-truename nil
146 147
  "*Non-nil means visit a file under its truename.
The truename of a file is found by chasing all links
148 149 150
both at the file level and at the levels of the containing directories."
  :type 'boolean
  :group 'find-file)
151

152
(defcustom revert-without-query
153
  nil
154 155 156
  "*Specify which files should be reverted without query.
The value is a list of regular expressions.
If the file name matches one of these regular expressions,
157
then `revert-buffer' reverts the file without querying
158
if the file has changed on disk and you have not edited the buffer."
159
  :type '(repeat regexp)
160
  :group 'find-file)
161

162 163 164 165 166 167 168 169
(defvar buffer-file-number nil
  "The device number and file number of the file visited in the current buffer.
The value is a list of the form (FILENUM DEVNUM).
This pair of numbers uniquely identifies the file.
If the buffer is visiting a new file, the value is nil.")
(make-variable-buffer-local 'buffer-file-number)
(put 'buffer-file-number 'permanent-local t)

170 171 172
(defvar buffer-file-numbers-unique (not (memq system-type '(windows-nt)))
  "Non-nil means that buffer-file-number uniquely identifies files.")

173 174
(defvar file-name-invalid-regexp
  (cond ((and (eq system-type 'ms-dos) (not (msdos-long-file-names)))
175
	 (concat "^\\([^A-Z[-`a-z]\\|..+\\)?:\\|" ; colon except after drive
176
		 "[+, ;=|<>\"?*]\\|\\[\\|\\]\\|"  ; invalid characters
177
		 "[\000-\031]\\|"		  ; control characters
178 179 180
		 "\\(/\\.\\.?[^/]\\)\\|"	  ; leading dots
		 "\\(/[^/.]+\\.[^/.]*\\.\\)"))	  ; more than a single dot
	((memq system-type '(ms-dos windows-nt))
181
	 (concat "^\\([^A-Z[-`a-z]\\|..+\\)?:\\|" ; colon except after drive
182
		 "[|<>\"?*\000-\031]"))		  ; invalid characters
183 184 185
	(t "[\000]"))
  "Regexp recognizing file names which aren't allowed by the filesystem.")

186
(defcustom file-precious-flag nil
Roland McGrath's avatar
Roland McGrath committed
187
  "*Non-nil means protect against I/O errors while saving files.
Karl Heuer's avatar
Karl Heuer committed
188
Some modes set this non-nil in particular buffers.
189 190 191 192 193 194 195

This feature works by writing the new contents into a temporary file
and then renaming the temporary file to replace the original.
In this way, any I/O error in writing leaves the original untouched,
and there is never any instant where the file is nonexistent.

Note that this feature forces backups to be made by copying.
Karl Heuer's avatar
Karl Heuer committed
196
Yet, at the same time, saving a precious file
197 198 199
breaks any hard links between it and other files."
  :type 'boolean
  :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
200

201
(defcustom version-control nil
Roland McGrath's avatar
Roland McGrath committed
202 203 204
  "*Control use of version numbers for backup files.
t means make numeric backup versions unconditionally.
nil means make them for files that have some already.
205
`never' means do not make them."
206 207 208
  :type '(choice (const :tag "Never" never)
		 (const :tag "If existing" nil)
		 (other :tag "Always" t))
209 210 211 212 213 214 215 216 217 218
  :group 'backup
  :group 'vc)

(defcustom dired-kept-versions 2
  "*When cleaning directory, number of versions to keep."
  :type 'integer
  :group 'backup
  :group 'dired)

(defcustom delete-old-versions nil
219
  "*If t, delete excess backup versions silently.
220 221 222
If nil, ask confirmation.  Any other value prevents any trimming."
  :type '(choice (const :tag "Delete" t)
		 (const :tag "Ask" nil)
223
		 (other :tag "Leave" other))
224 225 226 227 228 229 230 231
  :group 'backup)

(defcustom kept-old-versions 2
  "*Number of oldest versions to keep when a new numbered backup is made."
  :type 'integer
  :group 'backup)

(defcustom kept-new-versions 2
Roland McGrath's avatar
Roland McGrath committed
232
  "*Number of newest versions to keep when a new numbered backup is made.
233 234 235
Includes the new backup.  Must be > 0"
  :type 'integer
  :group 'backup)
Roland McGrath's avatar
Roland McGrath committed
236

237
(defcustom require-final-newline nil
Roland McGrath's avatar
Roland McGrath committed
238 239
  "*Value of t says silently ensure a file ends in a newline when it is saved.
Non-nil but not t says ask user whether to add a newline when there isn't one.
240
nil means don't add newlines."
241 242
  :type '(choice (const :tag "Off" nil)
		 (const :tag "Add" t)
243
		 (other :tag "Ask" ask))
244
  :group 'editing-basics)
Roland McGrath's avatar
Roland McGrath committed
245

246 247 248 249
(defcustom auto-save-default t
  "*Non-nil says by default do auto-saving of every file-visiting buffer."
  :type 'boolean
  :group 'auto-save)
Roland McGrath's avatar
Roland McGrath committed
250

251
(defcustom auto-save-visited-file-name nil
Roland McGrath's avatar
Roland McGrath committed
252
  "*Non-nil says auto-save a buffer in the file it is visiting, when practical.
253 254 255
Normally auto-save files are written under other names."
  :type 'boolean
  :group 'auto-save)
Roland McGrath's avatar
Roland McGrath committed
256

257
(defcustom save-abbrevs nil
Roland McGrath's avatar
Roland McGrath committed
258
  "*Non-nil means save word abbrevs too when files are saved.
259 260 261
Loading an abbrev file sets this to t."
  :type 'boolean
  :group 'abbrev)
Roland McGrath's avatar
Roland McGrath committed
262

263 264 265 266
(defcustom find-file-run-dired t
  "*Non-nil says run dired if `find-file' is given the name of a directory."
  :type 'boolean
  :group 'find-file)
Roland McGrath's avatar
Roland McGrath committed
267

268 269
;;;It is not useful to make this a local variable.
;;;(put 'find-file-not-found-hooks 'permanent-local t)
Roland McGrath's avatar
Roland McGrath committed
270 271 272 273 274 275
(defvar find-file-not-found-hooks nil
  "List of functions to be called for `find-file' on nonexistent file.
These functions are called as soon as the error is detected.
`buffer-file-name' is already set up.
The functions are called in the order given until one of them returns non-nil.")

276 277
;;;It is not useful to make this a local variable.
;;;(put 'find-file-hooks 'permanent-local t)
Roland McGrath's avatar
Roland McGrath committed
278 279 280 281 282 283 284 285
(defvar find-file-hooks nil
  "List of functions to be called after a buffer is loaded from a file.
The buffer's local variables (if any) will have been processed before the
functions are called.")

(defvar write-file-hooks nil
  "List of functions to be called before writing out a buffer to a file.
If one of them returns non-nil, the file is considered already written
Jim Blandy's avatar
Jim Blandy committed
286 287 288
and the rest are not called.
These hooks are considered to pertain to the visited file.
So this list is cleared if you change the visited file name.
289 290 291

Don't make this variable buffer-local; instead, use `local-write-file-hooks'.
See also `write-contents-hooks'.")
292 293
;;; However, in case someone does make it local...
(put 'write-file-hooks 'permanent-local t)
294 295 296 297

(defvar local-write-file-hooks nil
  "Just like `write-file-hooks', except intended for per-buffer use.
The functions in this list are called before the ones in
298 299 300 301 302 303
`write-file-hooks'.

This variable is meant to be used for hooks that have to do with a
particular visited file.  Therefore, it is a permanent local, so that
changing the major mode does not clear it.  However, calling
`set-visited-file-name' does clear it.")
304 305
(make-variable-buffer-local 'local-write-file-hooks)
(put 'local-write-file-hooks 'permanent-local t)
Jim Blandy's avatar
Jim Blandy committed
306 307 308 309 310

(defvar write-contents-hooks nil
  "List of functions to be called before writing out a buffer to a file.
If one of them returns non-nil, the file is considered already written
and the rest are not called.
311 312 313 314

This variable is meant to be used for hooks that pertain to the
buffer's contents, not to the particular visited file; thus,
`set-visited-file-name' does not clear this variable; but changing the
315 316 317
major mode does clear it.

This variable automatically becomes buffer-local whenever it is set.
Karl Heuer's avatar
Karl Heuer committed
318
If you use `add-hook' to add elements to the list, use nil for the
319
LOCAL argument.
320

Jim Blandy's avatar
Jim Blandy committed
321
See also `write-file-hooks'.")
322
(make-variable-buffer-local 'write-contents-hooks)
Roland McGrath's avatar
Roland McGrath committed
323

324
(defcustom enable-local-variables t
325
  "*Control use of local variables in files you visit.
Roland McGrath's avatar
Roland McGrath committed
326
The value can be t, nil or something else.
327
A value of t means file local variables specifications are obeyed;
Roland McGrath's avatar
Roland McGrath committed
328 329
nil means they are ignored; anything else means query.

330
The command \\[normal-mode] always obeys file local variable
331 332 333
specifications and ignores this variable."
  :type '(choice (const :tag "Obey" t)
		 (const :tag "Ignore" nil)
334
		 (other :tag "Query" other))
335
  :group 'find-file)
Roland McGrath's avatar
Roland McGrath committed
336

337 338 339 340 341
(defvar local-enable-local-variables t
  "Like `enable-local-variables' but meant for buffer-local bindings.
If a major mode sets this to nil, buffer-locally, then any local
variables list in the file will be ignored.")

342
(defcustom enable-local-eval 'maybe
343 344 345 346 347 348
  "*Control processing of the \"variable\" `eval' in a file's local variables.
The value can be t, nil or something else.
A value of t means obey `eval' variables;
nil means ignore them; anything else means query.

The command \\[normal-mode] always obeys local-variables lists
349 350 351
and ignores this variable."
  :type '(choice (const :tag "Obey" t)
		 (const :tag "Ignore" nil)
352
		 (other :tag "Query" other))
353
  :group 'find-file)
Roland McGrath's avatar
Roland McGrath committed
354 355 356

;; Avoid losing in versions where CLASH_DETECTION is disabled.
(or (fboundp 'lock-buffer)
357
    (defalias 'lock-buffer 'ignore))
Roland McGrath's avatar
Roland McGrath committed
358
(or (fboundp 'unlock-buffer)
359
    (defalias 'unlock-buffer 'ignore))
360 361
(or (fboundp 'file-locked-p)
    (defalias 'file-locked-p 'ignore))
362

363 364 365
(defvar view-read-only nil
  "*Non-nil means buffers visiting files read-only, do it in view mode.")

366 367
(defvar temporary-file-directory
  (file-name-as-directory
368 369 370 371 372 373
   (cond ((memq system-type '(ms-dos windows-nt))
	  (or (getenv "TEMP") (getenv "TMPDIR") (getenv "TMP") "c:/temp"))
	 ((memq system-type '(vax-vms axp-vms))
	  (or (getenv "TMPDIR") (getenv "TMP") (getenv "TEMP") "SYS$SCRATCH:"))
	 (t
	  (or (getenv "TMPDIR") (getenv "TMP") (getenv "TEMP") "/tmp"))))
374
  "The directory for writing temporary files.")
375

376 377 378
;; The system null device. (Should reference NULL_DEVICE from C.)
(defvar null-device "/dev/null" "The system null device.")

379 380 381 382 383 384 385
;; This hook function provides support for ange-ftp host name
;; completion.  It runs the usual ange-ftp hook, but only for
;; completion operations.  Having this here avoids the need
;; to load ange-ftp when it's not really in use.
(defun ange-ftp-completion-hook-function (op &rest args)
  (if (memq op '(file-name-completion file-name-all-completions))
      (apply 'ange-ftp-hook-function op args)
386 387 388 389 390
    (let ((inhibit-file-name-handlers
	   (cons 'ange-ftp-completion-hook-function
		 (and (eq inhibit-file-name-operation op)
		      inhibit-file-name-handlers)))
	  (inhibit-file-name-operation op))
391
      (apply op args))))
392 393 394 395 396 397 398

(defun convert-standard-filename (filename)
  "Convert a standard file's name to something suitable for the current OS.
This function's standard definition is trivial; it just returns the argument.
However, on some systems, the function is redefined
with a definition that really does change some file names."
  filename)
Roland McGrath's avatar
Roland McGrath committed
399 400 401 402 403 404

(defun pwd ()
  "Show the current default directory."
  (interactive nil)
  (message "Directory %s" default-directory))

405 406 407 408 409
(defvar cd-path nil
  "Value of the CDPATH environment variable, as a list.
Not actually set up until the first time you you use it.")

(defun parse-colon-path (cd-path)
410
  "Explode a colon-separated search path into a list of directory names."
411 412
  (and cd-path
       (let (cd-prefix cd-list (cd-start 0) cd-colon)
413 414
	 (setq cd-path (concat cd-path path-separator))
	 (while (setq cd-colon (string-match path-separator cd-path cd-start))
415
	   (setq cd-list
416
		 (nconc cd-list
417 418 419
			(list (if (= cd-start cd-colon)
				   nil
				(substitute-in-file-name
420 421
				 (file-name-as-directory
				  (substring cd-path cd-start cd-colon)))))))
422 423 424 425
	   (setq cd-start (+ cd-colon 1)))
	 cd-list)))

(defun cd-absolute (dir)
426
  "Change current directory to given absolute file name DIR."
427 428
  ;; Put the name into directory syntax now,
  ;; because otherwise expand-file-name may give some bad results.
Roland McGrath's avatar
Roland McGrath committed
429 430
  (if (not (eq system-type 'vax-vms))
      (setq dir (file-name-as-directory dir)))
431
  (setq dir (abbreviate-file-name (expand-file-name dir)))
Roland McGrath's avatar
Roland McGrath committed
432
  (if (not (file-directory-p dir))
433 434
      (if (file-exists-p dir)
	  (error "%s is not a directory" dir)
435
	(error "%s: no such directory" dir))
Roland McGrath's avatar
Roland McGrath committed
436 437
    (if (file-executable-p dir)
	(setq default-directory dir)
438
      (error "Cannot cd to %s:  Permission denied" dir))))
Roland McGrath's avatar
Roland McGrath committed
439

440 441
(defun cd (dir)
  "Make DIR become the current buffer's default directory.
442 443
If your environment includes a `CDPATH' variable, try each one of that
colon-separated list of directories when resolving a relative directory name."
444 445
  (interactive
   (list (read-file-name "Change default directory: "
446 447 448
			 default-directory default-directory
			 (and (member cd-path '(nil ("./")))
			      (null (getenv "CDPATH"))))))
449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464
  (if (file-name-absolute-p dir)
      (cd-absolute (expand-file-name dir))
    (if (null cd-path)
	(let ((trypath (parse-colon-path (getenv "CDPATH"))))
	  (setq cd-path (or trypath (list "./")))))
    (if (not (catch 'found
	       (mapcar
		(function (lambda (x)
			    (let ((f (expand-file-name (concat x dir))))
			      (if (file-directory-p f)
				  (progn
				    (cd-absolute f)
				    (throw 'found t))))))
		cd-path)
	       nil))
	(error "No such directory found via CDPATH environment variable"))))
465

Roland McGrath's avatar
Roland McGrath committed
466 467 468 469 470 471 472 473 474 475
(defun load-file (file)
  "Load the Lisp file named FILE."
  (interactive "fLoad file: ")
  (load (expand-file-name file) nil nil t))

(defun load-library (library)
  "Load the library named LIBRARY.
This is an interface to the function `load'."
  (interactive "sLoad library: ")
  (load library))
476

Karl Heuer's avatar
Karl Heuer committed
477
(defun file-local-copy (file &optional buffer)
478 479 480
  "Copy the file FILE into a temporary file on this machine.
Returns the name of the local copy, or nil, if FILE is directly
accessible."
481
  (let ((handler (find-file-name-handler file 'file-local-copy)))
482 483 484
    (if handler
	(funcall handler 'file-local-copy file)
      nil)))
485

486
(defun file-truename (filename &optional counter prev-dirs)
487 488 489
  "Return the truename of FILENAME, which should be absolute.
The truename of a file name is found by chasing symbolic links
both at the level of the file and at the level of the directories
490 491 492 493 494 495 496 497
containing it, until no links are left at any level.

The arguments COUNTER and PREV-DIRS are used only in recursive calls.
Do not specify them in other calls."
  ;; COUNTER can be a cons cell whose car is the count of how many more links
  ;; to chase before getting an error.
  ;; PREV-DIRS can be a cons cell whose car is an alist
  ;; of truenames we've just recently computed.
498 499 500

  ;; The last test looks dubious, maybe `+' is meant here?  --simon.
  (if (or (string= filename "") (string= filename "~")
501 502
	  (and (string= (substring filename 0 1) "~")
	       (string-match "~[^/]*" filename)))
503 504 505 506
      (progn
	(setq filename (expand-file-name filename))
	(if (string= filename "")
	    (setq filename "/"))))
507
  (or counter (setq counter (list 100)))
508 509 510 511 512 513 514 515 516
  (let (done
	;; For speed, remove the ange-ftp completion handler from the list.
	;; We know it's not needed here.
	;; For even more speed, do this only on the outermost call.
	(file-name-handler-alist
	 (if prev-dirs file-name-handler-alist
	   (let ((tem (copy-sequence file-name-handler-alist)))
	     (delq (rassq 'ange-ftp-completion-hook-function tem) tem)))))
    (or prev-dirs (setq prev-dirs (list nil)))
517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543

    ;; andrewi@harlequin.co.uk - none of the following code (except for
    ;; invoking the file-name handler) currently applies on Windows
    ;; (ie. there are no native symlinks), but there is an issue with
    ;; case differences being ignored by the OS, and short "8.3 DOS"
    ;; name aliases existing for all files.  (The short names are not
    ;; reported by directory-files, but can be used to refer to files.)
    ;; It seems appropriate for file-truename to resolve these issues in
    ;; the most natural way, which on Windows is to call the function
    ;; `w32-long-file-name' - this returns the exact name of a file as
    ;; it is stored on disk (expanding short name aliases with the full
    ;; name in the process).
    (if (eq system-type 'windows-nt)
      (let ((handler (find-file-name-handler filename 'file-truename))
	    newname)
	;; For file name that has a special handler, call handler.
	;; This is so that ange-ftp can save time by doing a no-op.
	(if handler
	    (setq filename (funcall handler 'file-truename filename))
	  ;; If filename contains a wildcard, newname will be the old name.
	  (if (string-match "[*?]" filename)
	      (setq newname filename)
	    ;; If filename doesn't exist, newname will be nil.
	    (setq newname (w32-long-file-name filename)))
	  (setq filename (or newname filename)))
	(setq done t)))

544 545 546 547 548 549 550 551 552 553 554 555
    ;; If this file directly leads to a link, process that iteratively
    ;; so that we don't use lots of stack.
    (while (not done)
      (setcar counter (1- (car counter)))
      (if (< (car counter) 0)
	  (error "Apparent cycle of symbolic links for %s" filename))
      (let ((handler (find-file-name-handler filename 'file-truename)))
	;; For file name that has a special handler, call handler.
	;; This is so that ange-ftp can save time by doing a no-op.
	(if handler
	    (setq filename (funcall handler 'file-truename filename)
		  done t)
556
	  (let ((dir (or (file-name-directory filename) default-directory))
557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594
		target dirfile)
	    ;; Get the truename of the directory.
	    (setq dirfile (directory-file-name dir))
	    ;; If these are equal, we have the (or a) root directory.
	    (or (string= dir dirfile)
		;; If this is the same dir we last got the truename for,
		;; save time--don't recalculate.
		(if (assoc dir (car prev-dirs))
		    (setq dir (cdr (assoc dir (car prev-dirs))))
		  (let ((old dir)
			(new (file-name-as-directory (file-truename dirfile counter prev-dirs))))
		    (setcar prev-dirs (cons (cons old new) (car prev-dirs)))
		    (setq dir new))))
	    (if (equal ".." (file-name-nondirectory filename))
		(setq filename
		      (directory-file-name (file-name-directory (directory-file-name dir)))
		      done t)
	      (if (equal "." (file-name-nondirectory filename))
		  (setq filename (directory-file-name dir)
			done t)
		;; Put it back on the file name.
		(setq filename (concat dir (file-name-nondirectory filename)))
		;; Is the file name the name of a link?
		(setq target (file-symlink-p filename))
		(if target
		    ;; Yes => chase that link, then start all over
		    ;; since the link may point to a directory name that uses links.
		    ;; We can't safely use expand-file-name here
		    ;; since target might look like foo/../bar where foo
		    ;; is itself a link.  Instead, we handle . and .. above.
		    (setq filename
			  (if (file-name-absolute-p target)
			      target
			    (concat dir target))
			  done nil)
		  ;; No, we are done!
		  (setq done t))))))))
    filename))
595

596 597 598 599 600 601
(defun file-chase-links (filename)
  "Chase links in FILENAME until a name that is not a link.
Does not examine containing directories for links,
unlike `file-truename'."
  (let (tem (count 100) (newname filename))
    (while (setq tem (file-symlink-p newname))
602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622
      (save-match-data
	(if (= count 0)
	    (error "Apparent cycle of symbolic links for %s" filename))
	;; In the context of a link, `//' doesn't mean what Emacs thinks.
	(while (string-match "//+" tem)
	  (setq tem (replace-match "/" nil nil tem)))
	;; Handle `..' by hand, since it needs to work in the
	;; target of any directory symlink.
	;; This code is not quite complete; it does not handle
	;; embedded .. in some cases such as ./../foo and foo/bar/../../../lose.
	(while (string-match "\\`\\.\\./" tem)
	  (setq tem (substring tem 3))
	  (setq newname (expand-file-name newname))
	  ;; Chase links in the default dir of the symlink.
	  (setq newname
		(file-chase-links
		 (directory-file-name (file-name-directory newname))))
	  ;; Now find the parent of that dir.
	  (setq newname (file-name-directory newname)))
	(setq newname (expand-file-name tem (file-name-directory newname)))
	(setq count (1- count))))
623
    newname))
Roland McGrath's avatar
Roland McGrath committed
624

625 626 627 628
(defun switch-to-buffer-other-window (buffer &optional norecord)
  "Select buffer BUFFER in another window.
Optional second arg NORECORD non-nil means
do not put this buffer at the front of the list of recently selected ones."
Roland McGrath's avatar
Roland McGrath committed
629 630
  (interactive "BSwitch to buffer in other window: ")
  (let ((pop-up-windows t))
631
    (pop-to-buffer buffer t norecord)))
Roland McGrath's avatar
Roland McGrath committed
632

633 634 635 636
(defun switch-to-buffer-other-frame (buffer &optional norecord)
  "Switch to buffer BUFFER in another frame.
Optional second arg NORECORD non-nil means
do not put this buffer at the front of the list of recently selected ones."
Jim Blandy's avatar
Jim Blandy committed
637 638
  (interactive "BSwitch to buffer in other frame: ")
  (let ((pop-up-frames t))
639
    (pop-to-buffer buffer t norecord)
640
    (raise-frame (window-frame (selected-window)))))
Jim Blandy's avatar
Jim Blandy committed
641

642
(defun find-file (filename)
Roland McGrath's avatar
Roland McGrath committed
643 644
  "Edit file FILENAME.
Switch to a buffer visiting file FILENAME,
645 646 647
creating one if none already exists."
  (interactive "FFind file: ")
  (switch-to-buffer (find-file-noselect filename)))
648

649
(defun find-file-other-window (filename)
Roland McGrath's avatar
Roland McGrath committed
650 651 652
  "Edit file FILENAME, in another window.
May create a new window, or reuse an existing one.
See the function `display-buffer'."
653 654
  (interactive "FFind file in other window: ")
  (switch-to-buffer-other-window (find-file-noselect filename)))
Roland McGrath's avatar
Roland McGrath committed
655

656
(defun find-file-other-frame (filename)
Jim Blandy's avatar
Jim Blandy committed
657 658
  "Edit file FILENAME, in another frame.
May create a new frame, or reuse an existing one.
Jim Blandy's avatar
Jim Blandy committed
659
See the function `display-buffer'."
660 661
  (interactive "FFind file in other frame: ")
  (switch-to-buffer-other-frame (find-file-noselect filename)))
Jim Blandy's avatar
Jim Blandy committed
662

663
(defun find-file-read-only (filename)
Roland McGrath's avatar
Roland McGrath committed
664 665 666
  "Edit file FILENAME but don't allow changes.
Like \\[find-file] but marks buffer as read-only.
Use \\[toggle-read-only] to permit editing."
667 668
  (interactive "fFind file read-only: ")
  (find-file filename)
669
  (toggle-read-only 1)
670
  (current-buffer))
Roland McGrath's avatar
Roland McGrath committed
671

672
(defun find-file-read-only-other-window (filename)
Roland McGrath's avatar
Roland McGrath committed
673 674 675
  "Edit file FILENAME in another window but don't allow changes.
Like \\[find-file-other-window] but marks buffer as read-only.
Use \\[toggle-read-only] to permit editing."
676 677
  (interactive "fFind file read-only other window: ")
  (find-file-other-window filename)
678
  (toggle-read-only 1)
679
  (current-buffer))
Roland McGrath's avatar
Roland McGrath committed
680

681
(defun find-file-read-only-other-frame (filename)
Jim Blandy's avatar
Jim Blandy committed
682 683
  "Edit file FILENAME in another frame but don't allow changes.
Like \\[find-file-other-frame] but marks buffer as read-only.
Jim Blandy's avatar
Jim Blandy committed
684
Use \\[toggle-read-only] to permit editing."
685 686
  (interactive "fFind file read-only other frame: ")
  (find-file-other-frame filename)
687
  (toggle-read-only 1)
688
  (current-buffer))
Jim Blandy's avatar
Jim Blandy committed
689

690
(defun find-alternate-file-other-window (filename)
691
  "Find file FILENAME as a replacement for the file in the next window.
692
This command does not select that window."
693 694 695 696 697 698 699 700 701 702
  (interactive
   (save-selected-window
     (other-window 1)
     (let ((file buffer-file-name)
	   (file-name nil)
	   (file-dir nil))
       (and file
	    (setq file-name (file-name-nondirectory file)
		  file-dir (file-name-directory file)))
       (list (read-file-name
703
	      "Find alternate file: " file-dir nil nil file-name)))))
704
  (if (one-window-p)
705
      (find-file-other-window filename)
706 707
    (save-selected-window
      (other-window 1)
708
      (find-alternate-file filename))))
709

710
(defun find-alternate-file (filename)
Roland McGrath's avatar
Roland McGrath committed
711 712
  "Find file FILENAME, select its buffer, kill previous buffer.
If the current buffer now contains an empty file that you just visited
713
\(presumably by mistake), use this command to visit the file you really want."
Roland McGrath's avatar
Roland McGrath committed
714 715 716 717 718 719 720
  (interactive
   (let ((file buffer-file-name)
	 (file-name nil)
	 (file-dir nil))
     (and file
	  (setq file-name (file-name-nondirectory file)
		file-dir (file-name-directory file)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
721
     (list (read-file-name
722
	    "Find alternate file: " file-dir nil nil file-name))))
723
  (and (buffer-modified-p) (buffer-file-name)
Roland McGrath's avatar
Roland McGrath committed
724 725 726 727 728 729
       ;; (not buffer-read-only)
       (not (yes-or-no-p (format "Buffer %s is modified; kill anyway? "
				 (buffer-name))))
       (error "Aborted"))
  (let ((obuf (current-buffer))
	(ofile buffer-file-name)
730 731
	(onum buffer-file-number)
	(otrue buffer-file-truename)
Roland McGrath's avatar
Roland McGrath committed
732
	(oname (buffer-name)))
733 734
    (if (get-buffer " **lose**")
	(kill-buffer " **lose**"))
Roland McGrath's avatar
Roland McGrath committed
735 736 737 738
    (rename-buffer " **lose**")
    (unwind-protect
	(progn
	  (unlock-buffer)
739 740 741
	  (setq buffer-file-name nil)
	  (setq buffer-file-number nil)
	  (setq buffer-file-truename nil)
742
	  (find-file filename))
Roland McGrath's avatar
Roland McGrath committed
743 744
      (cond ((eq obuf (current-buffer))
	     (setq buffer-file-name ofile)
745 746
	     (setq buffer-file-number onum)
	     (setq buffer-file-truename otrue)
Roland McGrath's avatar
Roland McGrath committed
747 748 749 750
	     (lock-buffer)
	     (rename-buffer oname))))
    (or (eq (current-buffer) obuf)
	(kill-buffer obuf))))
751

Roland McGrath's avatar
Roland McGrath committed
752 753 754 755 756 757 758 759 760
(defun create-file-buffer (filename)
  "Create a suitably named buffer for visiting FILENAME, and return it.
FILENAME (sans directory) is used unchanged if that name is free;
otherwise a string <2> or <3> or ... is appended to get an unused name."
  (let ((lastname (file-name-nondirectory filename)))
    (if (string= lastname "")
	(setq lastname filename))
    (generate-new-buffer lastname)))

Jim Blandy's avatar
Jim Blandy committed
761 762
(defun generate-new-buffer (name)
  "Create and return a buffer with a name based on NAME.
Richard M. Stallman's avatar
Richard M. Stallman committed
763
Choose the buffer's name using `generate-new-buffer-name'."
Jim Blandy's avatar
Jim Blandy committed
764 765
  (get-buffer-create (generate-new-buffer-name name)))

766
(defvar automount-dir-prefix "^/tmp_mnt/"
Jim Blandy's avatar
Jim Blandy committed
767 768
  "Regexp to match the automounter prefix in a directory name.")

769
(defvar abbreviated-home-dir nil
770
  "The user's homedir abbreviated according to `directory-abbrev-list'.")
771

Jim Blandy's avatar
Jim Blandy committed
772
(defun abbreviate-file-name (filename)
Richard M. Stallman's avatar
Richard M. Stallman committed
773
  "Return a version of FILENAME shortened using `directory-abbrev-alist'.
Jim Blandy's avatar
Jim Blandy committed
774
This also substitutes \"~\" for the user's home directory.
Richard M. Stallman's avatar
Richard M. Stallman committed
775
Type \\[describe-variable] directory-abbrev-alist RET for more information."
Jim Blandy's avatar
Jim Blandy committed
776
  ;; Get rid of the prefixes added by the automounter.
777 778
  (if (and automount-dir-prefix
	   (string-match automount-dir-prefix filename)
Jim Blandy's avatar
Jim Blandy committed
779 780 781
	   (file-exists-p (file-name-directory
			   (substring filename (1- (match-end 0))))))
      (setq filename (substring filename (1- (match-end 0)))))
Jim Blandy's avatar
Jim Blandy committed
782
  (let ((tail directory-abbrev-alist))
783 784
    ;; If any elt of directory-abbrev-alist matches this name,
    ;; abbreviate accordingly.
Jim Blandy's avatar
Jim Blandy committed
785 786 787 788 789
    (while tail
      (if (string-match (car (car tail)) filename)
	  (setq filename
		(concat (cdr (car tail)) (substring filename (match-end 0)))))
      (setq tail (cdr tail)))
790 791 792
    ;; Compute and save the abbreviated homedir name.
    ;; We defer computing this until the first time it's needed, to
    ;; give time for directory-abbrev-alist to be set properly.
793 794
    ;; We include a slash at the end, to avoid spurious matches
    ;; such as `/usr/foobar' when the home dir is `/usr/foo'.
795 796 797
    (or abbreviated-home-dir
	(setq abbreviated-home-dir
	      (let ((abbreviated-home-dir "$foo"))
798 799
		(concat "^" (abbreviate-file-name (expand-file-name "~"))
			"\\(/\\|$\\)"))))
800

801 802
    ;; If FILENAME starts with the abbreviated homedir,
    ;; make it start with `~' instead.
803 804 805
    (if (and (string-match abbreviated-home-dir filename)
	     ;; If the home dir is just /, don't change it.
	     (not (and (= (match-end 0) 1)
806
		       (= (aref filename 0) ?/)))
807 808
	     ;; MS-DOS root directories can come with a drive letter;
	     ;; Novell Netware allows drive letters beyond `Z:'.
809
	     (not (and (or (eq system-type 'ms-dos)
810
			   (eq system-type 'windows-nt))
811
		       (save-match-data
812
			 (string-match "^[a-zA-`]:/$" filename)))))
Jim Blandy's avatar
Jim Blandy committed
813
	(setq filename
814
	      (concat "~"
815
		      (substring filename (match-beginning 1) (match-end 1))
816
		      (substring filename (match-end 0)))))
Jim Blandy's avatar
Jim Blandy committed
817 818
    filename))

819
(defcustom find-file-not-true-dirname-list nil
820 821 822 823
  "*List of logical names for which visiting shouldn't save the true dirname.
On VMS, when you visit a file using a logical name that searches a path,
you may or may not want the visited file name to record the specific
directory where the file was found.  If you *do not* want that, add the logical
824 825 826
name to this list as a string."
  :type '(repeat (string :tag "Name"))
  :group 'find-file)
827

828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844
(defun find-buffer-visiting (filename)
  "Return the buffer visiting file FILENAME (a string).
This is like `get-file-buffer', except that it checks for any buffer
visiting the same file, possibly under a different name.
If there is no such live buffer, return nil."
  (let ((buf (get-file-buffer filename))
	(truename (abbreviate-file-name (file-truename filename))))
    (or buf
	(let ((list (buffer-list)) found)
	  (while (and (not found) list)
	    (save-excursion
	      (set-buffer (car list))
	      (if (and buffer-file-name
		       (string= buffer-file-truename truename))
		  (setq found (car list))))
	    (setq list (cdr list)))
	  found)
845
	(let ((number (nthcdr 10 (file-attributes truename)))
846
	      (list (buffer-list)) found)
847 848
	  (and buffer-file-numbers-unique
	       number
849 850 851
	       (while (and (not found) list)
		 (save-excursion
		   (set-buffer (car list))
852 853
		   (if (and buffer-file-name
			    (equal buffer-file-number number)
854 855 856 857 858 859 860
			    ;; Verify this buffer's file number
			    ;; still belongs to its file.
			    (file-exists-p buffer-file-name)
			    (equal (nthcdr 10 (file-attributes buffer-file-name))
				   number))
		       (setq found (car list))))
		 (setq list (cdr list))))
861
	  found))))
862

863
(defun find-file-noselect (filename &optional nowarn rawfile)
Roland McGrath's avatar
Roland McGrath committed
864 865 866
  "Read file FILENAME into a buffer and return the buffer.
If a buffer exists visiting FILENAME, return that one, but
verify that the file has not changed since visited or saved.
867 868
The buffer is not selected, just returned to the caller.
Optional first arg NOWARN non-nil means suppress any warning messages.
869
Optional second arg RAWFILE non-nil means the file is read literally."
Jim Blandy's avatar
Jim Blandy committed
870 871 872
  (setq filename
	(abbreviate-file-name
	 (expand-file-name filename)))
Roland McGrath's avatar
Roland McGrath committed
873 874
  (if (file-directory-p filename)
      (if find-file-run-dired
875 876 877
	  (dired-noselect (if find-file-visit-truename
			      (abbreviate-file-name (file-truename filename))
			    filename))
878
	(error "%s is a directory" filename))
879 880 881 882
    (let* ((buf (get-file-buffer filename))
	   (truename (abbreviate-file-name (file-truename filename)))
	   (number (nthcdr 10 (file-attributes truename)))
	   ;; Find any buffer for a file which has same truename.
883
	   (other (and (not buf) (find-buffer-visiting filename))))
884
      ;; Let user know if there is a buffer with the same truename.
885 886
      (if other
	  (progn
887 888 889 890
	    (or nowarn
		(string-equal filename (buffer-file-name other))
		(message "%s and %s are the same file"
			 filename (buffer-file-name other)))
891 892 893
	    ;; Optionally also find that buffer.
	    (if (or find-file-existing-other-name find-file-visit-truename)
		(setq buf other))))
Roland McGrath's avatar
Roland McGrath committed
894
      (if buf
895
	  ;; We are using an existing buffer.
896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922
	  (progn
	    (or nowarn
		(verify-visited-file-modtime buf)
		(cond ((not (file-exists-p filename))
		       (error "File %s no longer exists!" filename))
		      ;; Certain files should be reverted automatically
		      ;; if they have changed on disk and not in the buffer.
		      ((and (not (buffer-modified-p buf))
			    (let ((tail revert-without-query)
				  (found nil))
			      (while tail
				(if (string-match (car tail) filename)
				    (setq found t))
				(setq tail (cdr tail)))
			      found))
		       (with-current-buffer buf
			 (message "Reverting file %s..." filename)
			 (revert-buffer t t)
			 (message "Reverting file %s...done" filename)))
		      ((yes-or-no-p
			(if (string= (file-name-nondirectory filename)
				     (buffer-name buf))
			    (format
			     (if (buffer-modified-p buf)
				 "File %s changed on disk.  Discard your edits? "
			       "File %s changed on disk.  Reread from disk? ")
			     (file-name-nondirectory filename))
923 924
			  (format
			   (if (buffer-modified-p buf)
925 926 927 928 929 930 931 932 933 934 935 936 937 938
			       "File %s changed on disk.  Discard your edits in %s? "
			     "File %s changed on disk.  Reread from disk into %s? ")
			   (file-name-nondirectory filename)
			   (buffer-name buf))))
		       (with-current-buffer buf
			 (revert-buffer t t)))))
	    (when (not (eq rawfile (not (null find-file-literally))))
	      (with-current-buffer buf
		(if (buffer-modified-p)
		    (if (y-or-n-p (if rawfile
				      "Save file and revisit literally? "
				    "Save file and revisit non-literally? "))
			(progn
			  (save-buffer)
939 940
			  (find-file-noselect-1 buf filename nowarn
						rawfile truename number))
941 942 943 944 945 946 947 948 949 950 951 952 953
		      (if (y-or-n-p (if rawfile
					"Discard your edits and revisit file literally? "
				      "Discard your edits and revisit file non-literally? "))
			  (find-file-noselect-1 buf filename nowarn
						rawfile truename number)
			(error (if rawfile "File already visited non-literally"
				 "File already visited literally"))))
		  (if (y-or-n-p (if rawfile
				    "Revisit file literally? "
				  "Revisit file non-literally? "))
		      (find-file-noselect-1 buf filename nowarn
					    rawfile truename number)
		    (error (if rawfile "File already visited non-literally"
954 955 956 957 958 959 960 961 962
			     "File already visited literally"))))))
	    ;; Return the buffer we are using.
	    buf)
	;; Create a new buffer.
	(setq buf (create-file-buffer filename))
	(set-buffer-major-mode buf)
	;; find-file-noselect-1 may use a different buffer.
	(find-file-noselect-1 buf filename nowarn
			      rawfile truename number)))))
963 964

(defun find-file-noselect-1 (buf filename nowarn rawfile truename number)
965 966
  (let ((inhibit-read-only t)
	error)
967 968
    (with-current-buffer buf
      (kill-local-variable 'find-file-literally)
969 970
      ;; Needed in case we are re-visiting the file with a different
      ;; text representation.
971
      (kill-local-variable 'buffer-file-coding-system)
972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
      (erase-buffer)
      (and (default-value 'enable-multibyte-characters)
	   (not rawfile)
	   (set-buffer-multibyte t))
      (if rawfile
	  (condition-case ()
	      (insert-file-contents-literally filename t)
	    (file-error
	     (when (and (file-exists-p filename)
			(not (file-readable-p filename)))
	       (kill-buffer buf)
	       (signal 'file-error (list "File is not readable"
					 filename)))
	     ;; Unconditionally set error
	     (setq error t)))
	(condition-case ()
	    (insert-file-contents filename t)
	  (file-error
	   (when (and (file-exists-p filename)
		      (not (file-readable-p filename)))
	     (kill-buffer buf)
	     (signal 'file-error (list "File is not readable"
				       filename)))
	   ;; Run find-file-not-found-hooks until one returns non-nil.
	   (or (run-hook-with-args-until-success 'find-file-not-found-hooks)
	       ;; If they fail too, set error.
	       (setq error t)))))
      ;; Find the file's truename, and maybe use that as visited name.
      (setq buffer-file-truename truename)
      (setq buffer-file-number number)
      ;; On VMS, we may want to remember which directory in a search list
      ;; the file was found in.
      (and (eq system-type 'vax-vms)
	   (let (logical)
	     (if (string-match ":" (file-name-directory filename))
		 (setq logical (substring (file-name-directory filename)
					  0 (match-beginning 0))))
	     (not (member logical find-file-not-true-dirname-list)))
	   (setq buffer-file-name buffer-file-truename))
      (if find-file-visit-truename
	  (setq buffer-file-name
		(setq filename
		      (expand-file-name buffer-file-truename))))
      ;; Set buffer's default directory to that of the file.
      (setq default-directory (file-name-directory filename))
      ;; Turn off backup files for certain file names.  Since
      ;; this is a permanent local, the major mode won't eliminate it.
      (and (not (funcall backup-enable-predicate buffer-file-name))
	   (progn
	     (make-local-variable 'backup-inhibited)
	     (setq backup-inhibited t)))
      (if rawfile
	  (progn
	    (set-buffer-multibyte nil)
	    (setq buffer-file-coding-system 'no-conversion)
	    (make-local-variable 'find-file-literally)
	    (setq find-file-literally t))
1029 1030
	(after-find-file error (not nowarn)))
      (current-buffer))))
1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072

(defun insert-file-contents-literally (filename &optional visit beg end replace)
  "Like `insert-file-contents', but only reads in the file literally.
A buffer may be modified in several ways after reading into the buffer,
to Emacs features such as format decoding, character code
conversion, find-file-hooks, automatic uncompression, etc.

This function ensures that none of these modifications will take place."
  (let ((format-alist nil)
	(after-insert-file-functions nil)
	(coding-system-for-read 'no-conversion)
	(coding-system-for-write 'no-conversion)
	(jka-compr-compression-info-list nil)
	(find-buffer-file-type-function
	 (if (fboundp 'find-buffer-file-type)
	     (symbol-function 'find-buffer-file-type)
	   nil)))
    (unwind-protect
	(progn
	  (fset 'find-buffer-file-type (lambda (filename) t))
	  (insert-file-contents filename visit beg end replace))
      (if find-buffer-file-type-function
	  (fset 'find-buffer-file-type find-buffer-file-type-function)
	(fmakunbound 'find-buffer-file-type)))))

(defun insert-file-literally (filename)
  "Insert contents of file FILENAME into buffer after point with no conversion.

This function is meant for the user to run interactively.
Don't call it from programs!  Use `insert-file-contents-literally' instead.
\(Its calling sequence is different; see its documentation)."
  (interactive "*fInsert file literally: ")
  (if (file-directory-p filename)
      (signal 'file-error (list "Opening input file" "file is a directory"
				filename)))
  (let ((tem (insert-file-contents-literally filename)))
    (push-mark (+ (point) (car (cdr tem))))))

(defvar find-file-literally nil
  "Non-nil if this buffer was made by `find-file-literally' or equivalent.
This is a permanent local.")
(put 'find-file-literally 'permanent-local t)
1073 1074 1075 1076 1077

(defun find-file-literally (filename) 
  "Visit file FILENAME with no conversion of any kind.
Format conversion and character code conversion are both disabled,
and multibyte characters are disabled in the resulting buffer.
1078 1079
The major mode used is Fundamental mode regardless of the file name,
and local variable specifications in the file are ignored.
1080 1081 1082
Automatic uncompression is also disabled.

You cannot absolutely rely on this function to result in
1083
visiting the file literally.  If Emacs already has a buffer
1084 1085 1086 1087 1088 1089
which is visiting the file, you get the existing buffer,
regardless of whether it was created literally or not.

In a Lisp program, if you want to be sure of accessing a file's
contents literally, you should create a temporary buffer and then read
the file contents into it using `insert-file-contents-literally'."
1090
  (interactive "FFind file literally: ")
1091
  (switch-to-buffer (find-file-noselect filename nil t)))
Roland McGrath's avatar
Roland McGrath committed
1092

1093 1094
(defvar after-find-file-from-revert-buffer nil)

1095
(defun after-find-file (&optional error warn noauto
1096 1097
				  after-find-file-from-revert-buffer
				  nomodes)
Roland McGrath's avatar
Roland McGrath committed
1098 1099
  "Called after finding a file and by the default revert function.
Sets buffer mode, parses local variables.
1100
Optional args ERROR, WARN, and NOAUTO: ERROR non-nil means there was an
Roland McGrath's avatar
Roland McGrath committed
1101 1102
error in reading the file.  WARN non-nil means warn if there
exists an auto-save file more recent than the visited file.
1103
NOAUTO means don't mess with auto-save mode.
1104 1105
Fourth arg AFTER-FIND-FILE-FROM-REVERT-BUFFER non-nil
 means this call was from `revert-buffer'.
1106 1107 1108
Fifth arg NOMODES non-nil means don't alter the file's modes.
Finishes by calling the functions in `find-file-hooks'
unless NOMODES is non-nil."
Roland McGrath's avatar
Roland McGrath committed
1109 1110 1111 1112 1113 1114 1115
  (setq buffer-read-only (not (file-writable-p buffer-file-name)))
  (if noninteractive
      nil
    (let* (not-serious
	   (msg
	    (cond ((and error (file-attributes buffer-file-name))
		   (setq buffer-read-only t)
1116
		   "File exists, but cannot be read.")
Roland McGrath's avatar
Roland McGrath committed
1117 1118 1119 1120
		  ((not buffer-read-only)
		   (if (and warn
			    (file-newer-than-file-p (make-auto-save-file-name)
						    buffer-file-name))
1121 1122
		       (format "%s has auto save data; consider M-x recover-file"
			       (file-name-nondirectory buffer-file-name))
Roland McGrath's avatar
Roland McGrath committed
1123 1124 1125 1126 1127 1128 1129
		     (setq not-serious t)
		     (if error "(New file)" nil)))
		  ((not error)
		   (setq not-serious t)
		   "Note: file is write protected")
		  ((file-attributes (directory-file-name default-directory))
		   "File not found and directory write-protected")
1130 1131
		  ((file-exists-p (file-name-directory buffer-file-name))
		   (setq buffer-read-only nil))