xref: /386bsd/usr/local/lib/emacs/19.25/lisp/files.el (revision a2142627)
1;;; files.el --- file input and output commands for Emacs
2
3;; Copyright (C) 1985, 86, 87, 92, 93, 94 Free Software Foundation, Inc.
4
5;; Maintainer: FSF
6
7;; This file is part of GNU Emacs.
8
9;; GNU Emacs is free software; you can redistribute it and/or modify
10;; it under the terms of the GNU General Public License as published by
11;; the Free Software Foundation; either version 2, or (at your option)
12;; any later version.
13
14;; GNU Emacs is distributed in the hope that it will be useful,
15;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17;; GNU General Public License for more details.
18
19;; You should have received a copy of the GNU General Public License
20;; along with GNU Emacs; see the file COPYING.  If not, write to
21;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
22
23;;; Commentary:
24
25;; Defines most of Emacs's file- and directory-handling functions,
26;; including basic file visiting, backup generation, link handling,
27;; ITS-id version control, load- and write-hook handling, and the like.
28
29;;; Code:
30
31(defconst delete-auto-save-files t
32  "*Non-nil means delete a buffer's auto-save file when the buffer is saved.")
33
34(defconst directory-abbrev-alist
35  nil
36  "*Alist of abbreviations for file directories.
37A list of elements of the form (FROM . TO), each meaning to replace
38FROM with TO when it appears in a directory name.  This replacement is
39done when setting up the default directory of a newly visited file.
40*Every* FROM string should start with `^'.
41
42Do not use `~' in the TO strings.
43They should be ordinary absolute directory names.
44
45Use this feature when you have directories which you normally refer to
46via absolute symbolic links.  Make TO the name of the link, and FROM
47the name it is linked to.")
48
49;;; Turn off backup files on VMS since it has version numbers.
50(defconst make-backup-files (not (eq system-type 'vax-vms))
51  "*Non-nil means make a backup of a file the first time it is saved.
52This can be done by renaming the file or by copying.
53
54Renaming means that Emacs renames the existing file so that it is a
55backup file, then writes the buffer into a new file.  Any other names
56that the old file had will now refer to the backup file.  The new file
57is owned by you and its group is defaulted.
58
59Copying means that Emacs copies the existing file into the backup
60file, then writes the buffer on top of the existing file.  Any other
61names that the old file had will now refer to the new (edited) file.
62The file's owner and group are unchanged.
63
64The choice of renaming or copying is controlled by the variables
65`backup-by-copying', `backup-by-copying-when-linked' and
66`backup-by-copying-when-mismatch'.  See also `backup-inhibited'.")
67
68;; Do this so that local variables based on the file name
69;; are not overridden by the major mode.
70(defvar backup-inhibited nil
71  "Non-nil means don't make a backup, regardless of the other parameters.
72This variable is intended for use by making it local to a buffer.
73But it is local only if you make it local.")
74(put 'backup-inhibited 'permanent-local t)
75
76(defconst backup-by-copying nil
77 "*Non-nil means always use copying to create backup files.
78See documentation of variable `make-backup-files'.")
79
80(defconst backup-by-copying-when-linked nil
81 "*Non-nil means use copying to create backups for files with multiple names.
82This causes the alternate names to refer to the latest version as edited.
83This variable is relevant only if `backup-by-copying' is nil.")
84
85(defconst backup-by-copying-when-mismatch nil
86  "*Non-nil means create backups by copying if this preserves owner or group.
87Renaming may still be used (subject to control of other variables)
88when it would not result in changing the owner or group of the file;
89that is, for files which are owned by you and whose group matches
90the default for a new file created there by you.
91This variable is relevant only if `backup-by-copying' is nil.")
92
93(defvar backup-enable-predicate
94  '(lambda (name)
95     (or (< (length name) 5)
96	 (not (string-equal "/tmp/" (substring name 0 5)))))
97  "Predicate that looks at a file name and decides whether to make backups.
98Called with an absolute file name as argument, it returns t to enable backup.")
99
100(defconst buffer-offer-save nil
101  "*Non-nil in a buffer means offer to save the buffer on exit
102even if the buffer is not visiting a file.
103Automatically local in all buffers.")
104(make-variable-buffer-local 'buffer-offer-save)
105
106(defconst find-file-existing-other-name nil
107  "*Non-nil means find a file under alternative names, in existing buffers.
108This means if any existing buffer is visiting the file you want
109under another name, you get the existing buffer instead of a new buffer.")
110
111(defconst find-file-visit-truename nil
112  "*Non-nil means visit a file under its truename.
113The truename of a file is found by chasing all links
114both at the file level and at the levels of the containing directories.")
115
116(defvar buffer-file-truename nil
117  "The abbreviated truename of the file visited in the current buffer.
118That is, (abbreviated-file-name (file-truename buffer-file-name)).
119This variable is automatically local in all buffers, when non-nil.")
120(make-variable-buffer-local 'buffer-file-truename)
121(put 'buffer-file-truename 'permanent-local t)
122
123(defvar buffer-file-number nil
124  "The device number and file number of the file visited in the current buffer.
125The value is a list of the form (FILENUM DEVNUM).
126This pair of numbers uniquely identifies the file.
127If the buffer is visiting a new file, the value is nil.")
128(make-variable-buffer-local 'buffer-file-number)
129(put 'buffer-file-number 'permanent-local t)
130
131(defconst file-precious-flag nil
132  "*Non-nil means protect against I/O errors while saving files.
133Some modes set this non-nil in particular buffers.")
134
135(defvar version-control nil
136  "*Control use of version numbers for backup files.
137t means make numeric backup versions unconditionally.
138nil means make them for files that have some already.
139`never' means do not make them.")
140
141(defvar dired-kept-versions 2
142  "*When cleaning directory, number of versions to keep.")
143
144(defvar trim-versions-without-asking nil
145  "*If t, deletes excess backup versions silently.
146If nil, asks confirmation.  Any other value prevents any trimming.")
147
148(defvar kept-old-versions 2
149  "*Number of oldest versions to keep when a new numbered backup is made.")
150
151(defvar kept-new-versions 2
152  "*Number of newest versions to keep when a new numbered backup is made.
153Includes the new backup.  Must be > 0")
154
155(defconst require-final-newline nil
156  "*Value of t says silently ensure a file ends in a newline when it is saved.
157Non-nil but not t says ask user whether to add a newline when there isn't one.
158nil means don't add newlines.")
159
160(defconst auto-save-default t
161  "*Non-nil says by default do auto-saving of every file-visiting buffer.")
162
163(defconst auto-save-visited-file-name nil
164  "*Non-nil says auto-save a buffer in the file it is visiting, when practical.
165Normally auto-save files are written under other names.")
166
167(defconst save-abbrevs nil
168  "*Non-nil means save word abbrevs too when files are saved.
169Loading an abbrev file sets this to t.")
170
171(defconst find-file-run-dired t
172  "*Non-nil says run dired if `find-file' is given the name of a directory.")
173
174;;;It is not useful to make this a local variable.
175;;;(put 'find-file-not-found-hooks 'permanent-local t)
176(defvar find-file-not-found-hooks nil
177  "List of functions to be called for `find-file' on nonexistent file.
178These functions are called as soon as the error is detected.
179`buffer-file-name' is already set up.
180The functions are called in the order given until one of them returns non-nil.")
181
182;;;It is not useful to make this a local variable.
183;;;(put 'find-file-hooks 'permanent-local t)
184(defvar find-file-hooks nil
185  "List of functions to be called after a buffer is loaded from a file.
186The buffer's local variables (if any) will have been processed before the
187functions are called.")
188
189(defvar write-file-hooks nil
190  "List of functions to be called before writing out a buffer to a file.
191If one of them returns non-nil, the file is considered already written
192and the rest are not called.
193These hooks are considered to pertain to the visited file.
194So this list is cleared if you change the visited file name.
195See also `write-contents-hooks'.
196Don't make this variable buffer-local; instead, use `local-write-file-hooks'.")
197;;; However, in case someone does make it local...
198(put 'write-file-hooks 'permanent-local t)
199
200(defvar local-write-file-hooks nil
201  "Just like `write-file-hooks', except intended for per-buffer use.
202The functions in this list are called before the ones in
203`write-file-hooks'.")
204(make-variable-buffer-local 'local-write-file-hooks)
205(put 'local-write-file-hooks 'permanent-local t)
206
207(defvar write-contents-hooks nil
208  "List of functions to be called before writing out a buffer to a file.
209If one of them returns non-nil, the file is considered already written
210and the rest are not called.
211These hooks are considered to pertain to the buffer's contents,
212not to the particular visited file; thus, `set-visited-file-name' does
213not clear this variable, but changing the major mode does clear it.
214See also `write-file-hooks'.")
215
216(defconst enable-local-variables t
217  "*Control use of local-variables lists in files you visit.
218The value can be t, nil or something else.
219A value of t means local-variables lists are obeyed;
220nil means they are ignored; anything else means query.
221
222The command \\[normal-mode] always obeys local-variables lists
223and ignores this variable.")
224
225(defconst enable-local-eval 'maybe
226  "*Control processing of the \"variable\" `eval' in a file's local variables.
227The value can be t, nil or something else.
228A value of t means obey `eval' variables;
229nil means ignore them; anything else means query.
230
231The command \\[normal-mode] always obeys local-variables lists
232and ignores this variable.")
233
234;; Avoid losing in versions where CLASH_DETECTION is disabled.
235(or (fboundp 'lock-buffer)
236    (defalias 'lock-buffer 'ignore))
237(or (fboundp 'unlock-buffer)
238    (defalias 'unlock-buffer 'ignore))
239
240;; This hook function provides support for ange-ftp host name
241;; completion.  It runs the usual ange-ftp hook, but only for
242;; completion operations.  Having this here avoids the need
243;; to load ange-ftp when it's not really in use.
244(defun ange-ftp-completion-hook-function (op &rest args)
245  (if (memq op '(file-name-completion file-name-all-completions))
246      (apply 'ange-ftp-hook-function op args)
247    (let ((inhibit-file-name-handlers
248	   (cons 'ange-ftp-completion-hook-function
249		 (and (eq inhibit-file-name-operation op)
250		      inhibit-file-name-handlers)))
251	  (inhibit-file-name-operation op))
252      (apply op args))))
253
254(defun pwd ()
255  "Show the current default directory."
256  (interactive nil)
257  (message "Directory %s" default-directory))
258
259(defvar cd-path nil
260  "Value of the CDPATH environment variable, as a list.
261Not actually set up until the first time you you use it.")
262
263(defun parse-colon-path (cd-path)
264  "Explode a colon-separated list of paths into a string list."
265  (and cd-path
266       (let (cd-prefix cd-list (cd-start 0) cd-colon)
267	 (setq cd-path (concat cd-path ":"))
268	 (while (setq cd-colon (string-match ":" cd-path cd-start))
269	   (setq cd-list
270		 (nconc cd-list
271			(list (if (= cd-start cd-colon)
272				   nil
273				(substitute-in-file-name
274				 (file-name-as-directory
275				  (substring cd-path cd-start cd-colon)))))))
276	   (setq cd-start (+ cd-colon 1)))
277	 cd-list)))
278
279(defun cd-absolute (dir)
280  "Change current directory to given absolute file name DIR."
281  (setq dir (abbreviate-file-name (expand-file-name dir)))
282  (if (not (eq system-type 'vax-vms))
283      (setq dir (file-name-as-directory dir)))
284  (if (not (file-directory-p dir))
285      (error "%s is not a directory" dir)
286    (if (file-executable-p dir)
287	(setq default-directory dir)
288      (error "Cannot cd to %s:  Permission denied" dir))))
289
290(defun cd (dir)
291  "Make DIR become the current buffer's default directory.
292If your environment includes a `CDPATH' variable, try each one of that
293colon-separated list of directories when resolving a relative directory name."
294  (interactive "FChange default directory: ")
295  (if (file-name-absolute-p dir)
296      (cd-absolute (expand-file-name dir))
297    (if (null cd-path)
298	(let ((trypath (parse-colon-path (getenv "CDPATH"))))
299	  (setq cd-path (or trypath (list "./")))))
300    (if (not (catch 'found
301	       (mapcar
302		(function (lambda (x)
303			    (let ((f (expand-file-name (concat x dir))))
304			      (if (file-directory-p f)
305				  (progn
306				    (cd-absolute f)
307				    (throw 'found t))))))
308		cd-path)
309	       nil))
310	(error "No such directory found via CDPATH environment variable"))))
311
312(defun load-file (file)
313  "Load the Lisp file named FILE."
314  (interactive "fLoad file: ")
315  (load (expand-file-name file) nil nil t))
316
317(defun load-library (library)
318  "Load the library named LIBRARY.
319This is an interface to the function `load'."
320  (interactive "sLoad library: ")
321  (load library))
322
323(defun file-local-copy (file &optional buffer)
324  "Copy the file FILE into a temporary file on this machine.
325Returns the name of the local copy, or nil, if FILE is directly
326accessible."
327  (let ((handler (find-file-name-handler file 'file-local-copy)))
328    (if handler
329	(funcall handler 'file-local-copy file)
330      nil)))
331
332(defun file-truename (filename)
333  "Return the truename of FILENAME, which should be absolute.
334The truename of a file name is found by chasing symbolic links
335both at the level of the file and at the level of the directories
336containing it, until no links are left at any level."
337  (if (or (string= filename "~")
338	  (and (string= (substring filename 0 1) "~")
339	       (string-match "~[^/]*" filename)))
340      (progn
341	(setq filename (expand-file-name filename))
342	(if (string= filename "")
343	    (setq filename "/"))))
344  (let ((handler (find-file-name-handler filename 'file-truename)))
345    ;; For file name that has a special handler, call handler.
346    ;; This is so that ange-ftp can save time by doing a no-op.
347    (if handler
348	(funcall handler 'file-truename filename)
349      (let ((dir (file-name-directory filename))
350	    target dirfile)
351	;; Get the truename of the directory.
352	(setq dirfile (directory-file-name dir))
353	;; If these are equal, we have the (or a) root directory.
354	(or (string= dir dirfile)
355	    (setq dir (file-name-as-directory (file-truename dirfile))))
356	(if (equal ".." (file-name-nondirectory filename))
357	    (directory-file-name (file-name-directory (directory-file-name dir)))
358	  (if (equal "." (file-name-nondirectory filename))
359	      (directory-file-name dir)
360	    ;; Put it back on the file name.
361	    (setq filename (concat dir (file-name-nondirectory filename)))
362	    ;; Is the file name the name of a link?
363	    (setq target (file-symlink-p filename))
364	    (if target
365		;; Yes => chase that link, then start all over
366		;; since the link may point to a directory name that uses links.
367		;; We can't safely use expand-file-name here
368		;; since target might look like foo/../bar where foo
369		;; is itself a link.  Instead, we handle . and .. above.
370		(if (file-name-absolute-p target)
371		    (file-truename target)
372		  (file-truename (concat dir target)))
373	      ;; No, we are done!
374	      filename)))))))
375
376(defun file-chase-links (filename)
377  "Chase links in FILENAME until a name that is not a link.
378Does not examine containing directories for links,
379unlike `file-truename'."
380  (let (tem (count 100) (newname filename))
381    (while (setq tem (file-symlink-p newname))
382      (if (= count 0)
383	  (error "Apparent cycle of symbolic links for %s" filename))
384      ;; In the context of a link, `//' doesn't mean what Emacs thinks.
385      (while (string-match "//+" tem)
386	(setq tem (concat (substring tem 0 (1+ (match-beginning 0)))
387			  (substring tem (match-end 0)))))
388      ;; Handle `..' by hand, since it needs to work in the
389      ;; target of any directory symlink.
390      ;; This code is not quite complete; it does not handle
391      ;; embedded .. in some cases such as ./../foo and foo/bar/../../../lose.
392      (while (string-match "\\`\\.\\./" tem)
393	(setq tem (substring tem 3))
394	(setq newname (file-name-as-directory
395		       ;; Do the .. by hand.
396		       (directory-file-name
397			(file-name-directory
398			 ;; Chase links in the default dir of the symlink.
399			 (file-chase-links
400			  (directory-file-name
401			   (file-name-directory newname))))))))
402      (setq newname (expand-file-name tem (file-name-directory newname)))
403      (setq count (1- count)))
404    newname))
405
406(defun switch-to-buffer-other-window (buffer)
407  "Select buffer BUFFER in another window."
408  (interactive "BSwitch to buffer in other window: ")
409  (let ((pop-up-windows t))
410    (pop-to-buffer buffer t)))
411
412(defun switch-to-buffer-other-frame (buffer)
413  "Switch to buffer BUFFER in another frame."
414  (interactive "BSwitch to buffer in other frame: ")
415  (let ((pop-up-frames t))
416    (pop-to-buffer buffer t)))
417
418(defun find-file (filename)
419  "Edit file FILENAME.
420Switch to a buffer visiting file FILENAME,
421creating one if none already exists."
422  (interactive "FFind file: ")
423  (switch-to-buffer (find-file-noselect filename)))
424
425(defun find-file-other-window (filename)
426  "Edit file FILENAME, in another window.
427May create a new window, or reuse an existing one.
428See the function `display-buffer'."
429  (interactive "FFind file in other window: ")
430  (switch-to-buffer-other-window (find-file-noselect filename)))
431
432(defun find-file-other-frame (filename)
433  "Edit file FILENAME, in another frame.
434May create a new frame, or reuse an existing one.
435See the function `display-buffer'."
436  (interactive "FFind file in other frame: ")
437  (switch-to-buffer-other-frame (find-file-noselect filename)))
438
439(defun find-file-read-only (filename)
440  "Edit file FILENAME but don't allow changes.
441Like \\[find-file] but marks buffer as read-only.
442Use \\[toggle-read-only] to permit editing."
443  (interactive "fFind file read-only: ")
444  (find-file filename)
445  (setq buffer-read-only t)
446  (current-buffer))
447
448(defun find-file-read-only-other-window (filename)
449  "Edit file FILENAME in another window but don't allow changes.
450Like \\[find-file-other-window] but marks buffer as read-only.
451Use \\[toggle-read-only] to permit editing."
452  (interactive "fFind file read-only other window: ")
453  (find-file-other-window filename)
454  (setq buffer-read-only t)
455  (current-buffer))
456
457(defun find-file-read-only-other-frame (filename)
458  "Edit file FILENAME in another frame but don't allow changes.
459Like \\[find-file-other-frame] but marks buffer as read-only.
460Use \\[toggle-read-only] to permit editing."
461  (interactive "fFind file read-only other frame: ")
462  (find-file-other-frame filename)
463  (setq buffer-read-only t)
464  (current-buffer))
465
466(defun find-alternate-file (filename)
467  "Find file FILENAME, select its buffer, kill previous buffer.
468If the current buffer now contains an empty file that you just visited
469\(presumably by mistake), use this command to visit the file you really want."
470  (interactive
471   (let ((file buffer-file-name)
472	 (file-name nil)
473	 (file-dir nil))
474     (and file
475	  (setq file-name (file-name-nondirectory file)
476		file-dir (file-name-directory file)))
477     (list (read-file-name
478	    "Find alternate file: " file-dir nil nil file-name))))
479  (and (buffer-modified-p)
480       ;; (not buffer-read-only)
481       (not (yes-or-no-p (format "Buffer %s is modified; kill anyway? "
482				 (buffer-name))))
483       (error "Aborted"))
484  (let ((obuf (current-buffer))
485	(ofile buffer-file-name)
486	(onum buffer-file-number)
487	(otrue buffer-file-truename)
488	(oname (buffer-name)))
489    (rename-buffer " **lose**")
490    (setq buffer-file-name nil)
491    (setq buffer-file-number nil)
492    (setq buffer-file-truename nil)
493    (unwind-protect
494	(progn
495	  (unlock-buffer)
496	  (find-file filename))
497      (cond ((eq obuf (current-buffer))
498	     (setq buffer-file-name ofile)
499	     (setq buffer-file-number onum)
500	     (setq buffer-file-truename otrue)
501	     (lock-buffer)
502	     (rename-buffer oname))))
503    (or (eq (current-buffer) obuf)
504	(kill-buffer obuf))))
505
506(defun create-file-buffer (filename)
507  "Create a suitably named buffer for visiting FILENAME, and return it.
508FILENAME (sans directory) is used unchanged if that name is free;
509otherwise a string <2> or <3> or ... is appended to get an unused name."
510  (let ((lastname (file-name-nondirectory filename)))
511    (if (string= lastname "")
512	(setq lastname filename))
513    (generate-new-buffer lastname)))
514
515(defun generate-new-buffer (name)
516  "Create and return a buffer with a name based on NAME.
517Choose the buffer's name using `generate-new-buffer-name'."
518  (get-buffer-create (generate-new-buffer-name name)))
519
520(defconst automount-dir-prefix "^/tmp_mnt/"
521  "Regexp to match the automounter prefix in a directory name.")
522
523(defvar abbreviated-home-dir nil
524  "The user's homedir abbreviated according to `directory-abbrev-list'.")
525
526(defun abbreviate-file-name (filename)
527  "Return a version of FILENAME shortened using `directory-abbrev-alist'.
528This also substitutes \"~\" for the user's home directory.
529Type \\[describe-variable] directory-abbrev-alist RET for more information."
530  ;; Get rid of the prefixes added by the automounter.
531  (if (and (string-match automount-dir-prefix filename)
532	   (file-exists-p (file-name-directory
533			   (substring filename (1- (match-end 0))))))
534      (setq filename (substring filename (1- (match-end 0)))))
535  (let ((tail directory-abbrev-alist))
536    ;; If any elt of directory-abbrev-alist matches this name,
537    ;; abbreviate accordingly.
538    (while tail
539      (if (string-match (car (car tail)) filename)
540	  (setq filename
541		(concat (cdr (car tail)) (substring filename (match-end 0)))))
542      (setq tail (cdr tail)))
543    ;; Compute and save the abbreviated homedir name.
544    ;; We defer computing this until the first time it's needed, to
545    ;; give time for directory-abbrev-alist to be set properly.
546    ;; We include a slash at the end, to avoid spurious matches
547    ;; such as `/usr/foobar' when the home dir is `/usr/foo'.
548    (or abbreviated-home-dir
549	(setq abbreviated-home-dir
550	      (let ((abbreviated-home-dir "$foo"))
551		(concat "^" (abbreviate-file-name (expand-file-name "~"))
552			"\\(/\\|$\\)"))))
553
554    ;; If FILENAME starts with the abbreviated homedir,
555    ;; make it start with `~' instead.
556    (if (and (string-match abbreviated-home-dir filename)
557	     ;; If the home dir is just /, don't change it.
558	     (not (and (= (match-end 0) 1)
559		       (= (aref filename 0) ?/)))
560	     (not (and (eq system-type 'ms-dos)
561		       (save-match-data
562			 (string-match "^[a-zA-Z]:/$" filename)))))
563	(setq filename
564	      (concat "~"
565		      (substring filename (match-beginning 1) (match-end 1))
566		      (substring filename (match-end 0)))))
567    filename))
568
569(defvar find-file-not-true-dirname-list nil
570  "*List of logical names for which visiting shouldn't save the true dirname.
571On VMS, when you visit a file using a logical name that searches a path,
572you may or may not want the visited file name to record the specific
573directory where the file was found.  If you *do not* want that, add the logical
574name to this list as a string.")
575
576(defun find-buffer-visiting (filename)
577  "Return the buffer visiting file FILENAME (a string).
578This is like `get-file-buffer', except that it checks for any buffer
579visiting the same file, possibly under a different name.
580If there is no such live buffer, return nil."
581  (let ((buf (get-file-buffer filename))
582	(truename (abbreviate-file-name (file-truename filename))))
583    (or buf
584	(let ((list (buffer-list)) found)
585	  (while (and (not found) list)
586	    (save-excursion
587	      (set-buffer (car list))
588	      (if (and buffer-file-name
589		       (string= buffer-file-truename truename))
590		  (setq found (car list))))
591	    (setq list (cdr list)))
592	  found)
593	(let ((number (nthcdr 10 (file-attributes truename)))
594	      (list (buffer-list)) found)
595	  (and number
596	       (while (and (not found) list)
597		 (save-excursion
598		   (set-buffer (car list))
599		   (if (and buffer-file-name
600			    (equal buffer-file-number number)
601			    ;; Verify this buffer's file number
602			    ;; still belongs to its file.
603			    (file-exists-p buffer-file-name)
604			    (equal (nthcdr 10 (file-attributes buffer-file-name))
605				   number))
606		       (setq found (car list))))
607		 (setq list (cdr list))))
608	  found))))
609
610(defun find-file-noselect (filename &optional nowarn)
611  "Read file FILENAME into a buffer and return the buffer.
612If a buffer exists visiting FILENAME, return that one, but
613verify that the file has not changed since visited or saved.
614The buffer is not selected, just returned to the caller."
615  (setq filename
616	(abbreviate-file-name
617	 (expand-file-name filename)))
618  (if (file-directory-p filename)
619      (if find-file-run-dired
620	  (dired-noselect filename)
621	(error "%s is a directory." filename))
622    (let* ((buf (get-file-buffer filename))
623	   (truename (abbreviate-file-name (file-truename filename)))
624	   (number (nthcdr 10 (file-attributes truename)))
625	   ;; Find any buffer for a file which has same truename.
626	   (other (and (not buf) (find-buffer-visiting filename)))
627	   error)
628      ;; Let user know if there is a buffer with the same truename.
629      (if other
630	  (progn
631	    (or nowarn
632		(string-equal filename (buffer-file-name other))
633		(message "%s and %s are the same file"
634			 filename (buffer-file-name other)))
635	    ;; Optionally also find that buffer.
636	    (if (or find-file-existing-other-name find-file-visit-truename)
637		(setq buf other))))
638      (if buf
639	  (or nowarn
640	      (verify-visited-file-modtime buf)
641	      (cond ((not (file-exists-p filename))
642		     (error "File %s no longer exists!" filename))
643		    ((yes-or-no-p
644		      (format
645		       (if (buffer-modified-p buf)
646    "File %s changed on disk.  Discard your edits? "
647    "File %s changed on disk.  Read the new version? ")
648		       (file-name-nondirectory filename)))
649		     (save-excursion
650		       (set-buffer buf)
651		       (revert-buffer t t)))))
652	(save-excursion
653;;; The truename stuff makes this obsolete.
654;;;	  (let* ((link-name (car (file-attributes filename)))
655;;;		 (linked-buf (and (stringp link-name)
656;;;				  (get-file-buffer link-name))))
657;;;	    (if (bufferp linked-buf)
658;;;		(message "Symbolic link to file in buffer %s"
659;;;			 (buffer-name linked-buf))))
660	  (setq buf (create-file-buffer filename))
661	  (set-buffer buf)
662	  (erase-buffer)
663	  (condition-case ()
664	      (insert-file-contents filename t)
665	    (file-error
666	     (setq error t)
667	     ;; Run find-file-not-found-hooks until one returns non-nil.
668	     (let ((hooks find-file-not-found-hooks))
669	       (while (and hooks
670			   (not (and (funcall (car hooks))
671				     ;; If a hook succeeded, clear error.
672				     (progn (setq error nil)
673					    ;; Also exit the loop.
674					    t))))
675		 (setq hooks (cdr hooks))))))
676	  ;; Find the file's truename, and maybe use that as visited name.
677	  (setq buffer-file-truename truename)
678	  (setq buffer-file-number number)
679	  ;; On VMS, we may want to remember which directory in a search list
680	  ;; the file was found in.
681	  (and (eq system-type 'vax-vms)
682	       (let (logical)
683		 (if (string-match ":" (file-name-directory filename))
684		     (setq logical (substring (file-name-directory filename)
685					      0 (match-beginning 0))))
686		 (not (member logical find-file-not-true-dirname-list)))
687	       (setq buffer-file-name buffer-file-truename))
688	  (if find-file-visit-truename
689	      (setq buffer-file-name
690		    (setq filename
691			  (expand-file-name buffer-file-truename))))
692	  ;; Set buffer's default directory to that of the file.
693	  (setq default-directory (file-name-directory filename))
694	  ;; Turn off backup files for certain file names.  Since
695	  ;; this is a permanent local, the major mode won't eliminate it.
696	  (and (not (funcall backup-enable-predicate buffer-file-name))
697	       (progn
698		 (make-local-variable 'backup-inhibited)
699		 (setq backup-inhibited t)))
700	  (after-find-file error (not nowarn))))
701      buf)))
702
703(defun after-find-file (&optional error warn noauto)
704  "Called after finding a file and by the default revert function.
705Sets buffer mode, parses local variables.
706Optional args ERROR, WARN, and NOAUTO: ERROR non-nil means there was an
707error in reading the file.  WARN non-nil means warn if there
708exists an auto-save file more recent than the visited file.
709NOAUTO means don't mess with auto-save mode.
710Finishes by calling the functions in `find-file-hooks'."
711  (setq buffer-read-only (not (file-writable-p buffer-file-name)))
712  (if noninteractive
713      nil
714    (let* (not-serious
715	   (msg
716	    (cond ((and error (file-attributes buffer-file-name))
717		   (setq buffer-read-only t)
718		   "File exists, but cannot be read.")
719		  ((not buffer-read-only)
720		   (if (and warn
721			    (file-newer-than-file-p (make-auto-save-file-name)
722						    buffer-file-name))
723		       "Auto save file is newer; consider M-x recover-file"
724		     (setq not-serious t)
725		     (if error "(New file)" nil)))
726		  ((not error)
727		   (setq not-serious t)
728		   "Note: file is write protected")
729		  ((file-attributes (directory-file-name default-directory))
730		   "File not found and directory write-protected")
731		  ((file-exists-p (file-name-directory buffer-file-name))
732		   (setq buffer-read-only nil))
733		  (t
734		   (setq buffer-read-only nil)
735		   (if (file-exists-p (file-name-directory (directory-file-name (file-name-directory buffer-file-name))))
736		       "Use M-x make-dir RET RET to create the directory"
737		     "Use C-u M-x make-dir RET RET to create directory and its parents")))))
738      (if msg
739	  (progn
740	    (message msg)
741	    (or not-serious (sit-for 1 nil t)))))
742    (if (and auto-save-default (not noauto))
743	(auto-save-mode t)))
744  (normal-mode t)
745  (mapcar 'funcall find-file-hooks))
746
747(defun normal-mode (&optional find-file)
748  "Choose the major mode for this buffer automatically.
749Also sets up any specified local variables of the file.
750Uses the visited file name, the -*- line, and the local variables spec.
751
752This function is called automatically from `find-file'.  In that case,
753we may set up specified local variables depending on the value of
754`enable-local-variables': if it is t, we do; if it is nil, we don't;
755otherwise, we query.  `enable-local-variables' is ignored if you
756run `normal-mode' explicitly."
757  (interactive)
758  (or find-file (funcall (or default-major-mode 'fundamental-mode)))
759  (condition-case err
760      (set-auto-mode)
761    (error (message "File mode specification error: %s"
762		    (prin1-to-string err))))
763  (condition-case err
764      (let ((enable-local-variables (or (not find-file)
765					enable-local-variables)))
766	(hack-local-variables))
767    (error (message "File local-variables error: %s"
768		    (prin1-to-string err)))))
769
770(defvar auto-mode-alist (mapcar 'purecopy
771				'(("\\.text\\'" . text-mode)
772				  ("\\.c\\'" . c-mode)
773				  ("\\.h\\'" . c-mode)
774				  ("\\.tex\\'" . TeX-mode)
775				  ("\\.ltx\\'" . LaTeX-mode)
776				  ("\\.el\\'" . emacs-lisp-mode)
777				  ("\\.mm\\'" . nroff-mode)
778				  ("\\.me\\'" . nroff-mode)
779				  ("\\.ms\\'" . nroff-mode)
780				  ("\\.man\\'" . nroff-mode)
781				  ("\\.scm\\'" . scheme-mode)
782				  ("\\.l\\'" . lisp-mode)
783				  ("\\.lisp\\'" . lisp-mode)
784				  ("\\.f\\'" . fortran-mode)
785				  ("\\.for\\'" . fortran-mode)
786				  ("\\.p\\'" . pascal-mode)
787				  ("\\.pas\\'" . pascal-mode)
788				  ("\\.mss\\'" . scribe-mode)
789				  ("\\.pl\\'" . prolog-mode)
790				  ("\\.cc\\'" . c++-mode)
791				  ("\\.hh\\'" . c++-mode)
792				  ("\\.C\\'" . c++-mode)
793				  ("\\.H\\'" . c++-mode)
794;;;				  ("\\.mk\\'" . makefile-mode)
795;;;				  ("[Mm]akefile" . makefile-mode)
796;;; Less common extensions come here
797;;; so more common ones above are found faster.
798				  ("\\.texinfo\\'" . texinfo-mode)
799				  ("\\.texi\\'" . texinfo-mode)
800				  ("\\.s\\'" . asm-mode)
801				  ("ChangeLog\\'" . change-log-mode)
802				  ("change.log\\'" . change-log-mode)
803				  ("changelo\\'" . change-log-mode)
804				  ("ChangeLog.[0-9]+\\'" . change-log-mode)
805				  ("\\$CHANGE_LOG\\$\\.TXT" . change-log-mode)
806;; The following should come after the ChangeLog pattern
807;; for the sake of ChangeLog.1, etc.
808				  ("\\.[12345678]\\'" . nroff-mode)
809				  ("\\.TeX\\'" . TeX-mode)
810				  ("\\.sty\\'" . LaTeX-mode)
811				  ("\\.bbl\\'" . LaTeX-mode)
812				  ("\\.bib\\'" . bibtex-mode)
813				  ("\\.article\\'" . text-mode)
814				  ("\\.letter\\'" . text-mode)
815				  ("\\.tcl\\'" . tcl-mode)
816				  ("\\.lsp\\'" . lisp-mode)
817				  ("\\.awk\\'" . awk-mode)
818				  ("\\.prolog\\'" . prolog-mode)
819				  ("\\.tar\\'" . tar-mode)
820				  ;; Mailer puts message to be edited in
821				  ;; /tmp/Re.... or Message
822				  ("^/tmp/Re" . text-mode)
823				  ("/Message[0-9]*\\'" . text-mode)
824				  ;; some news reader is reported to use this
825				  ("^/tmp/fol/" . text-mode)
826				  ("\\.y\\'" . c-mode)
827				  ("\\.lex\\'" . c-mode)
828				  ("\\.oak\\'" . scheme-mode)
829				  ("\\.scm.[0-9]*\\'" . scheme-mode)
830				  ("\\.sgm\\'" . sgml-mode)
831				  ("\\.sgml\\'" . sgml-mode)
832				  ("\\.dtd\\'" . sgml-mode)
833				  ;; .emacs following a directory delimiter
834				  ;; in either Unix or VMS syntax.
835				  ("[]>:/]\\..*emacs\\'" . emacs-lisp-mode)
836				  ;; _emacs following a directory delimiter
837				  ;; in MsDos syntax
838				  ("[:/]_emacs\\'" . emacs-lisp-mode)
839				  ("\\.ml\\'" . lisp-mode)))
840  "\
841Alist of filename patterns vs corresponding major mode functions.
842Each element looks like (REGEXP . FUNCTION) or (REGEXP FUNCTION).
843Visiting a file whose name matches REGEXP causes FUNCTION to be called.
844If the element has the form (REGEXP FUNCTION), then after calling
845FUNCTION, we delete the suffix that matched REGEXP and search the list
846again for another match.")
847
848(defconst interpreter-mode-alist
849  '(("perl" . perl-mode)
850    ("wish" . tcl-mode)
851    ("wishx" . tcl-mode)
852    ("tcl" . tcl-mode)
853    ("tclsh" . tcl-mode)
854    ("awk" . awk-mode)
855    ("gawk" . awk-mode)
856    ("scm" . scheme-mode))
857  "Alist mapping interpreter names to major modes.
858This alist applies to files whose first line starts with `#!'.
859Each element looks like (INTERPRETER . MODE).
860The car of each element is compared with
861the name of the interpreter specified in the first line.
862If it matches, mode MODE is selected.")
863
864(defconst inhibit-first-line-modes-regexps '("\\.tar$")
865  "List of regexps; if one matches a file name, don't look for `-*-'.")
866
867(defvar user-init-file
868  "" ; set by command-line
869  "File name including directory of user's initialization file.")
870
871(defun set-auto-mode ()
872  "Select major mode appropriate for current buffer.
873This checks for a -*- mode tag in the buffer's text,
874compares the filename against the entries in `auto-mode-alist',
875or checks the interpreter that runs this file against
876`interpreter-mode-alist'.
877
878It does not check for the `mode:' local variable in the
879Local Variables section of the file; for that, use `hack-local-variables'.
880
881If `enable-local-variables' is nil, this function does not check for a
882-*- mode tag."
883  ;; Look for -*-MODENAME-*- or -*- ... mode: MODENAME; ... -*-
884  (let (beg end done)
885    (save-excursion
886      (goto-char (point-min))
887      (skip-chars-forward " \t\n")
888      (and enable-local-variables
889	   ;; Don't look for -*- if this file name matches any
890	   ;; of the regexps in inhibit-first-line-modes-regexps.
891	   (let ((temp inhibit-first-line-modes-regexps))
892	     (while (and temp
893			 (not (string-match (car temp)
894					    buffer-file-name)))
895	       (setq temp (cdr temp)))
896	     (not temp))
897	   (search-forward "-*-" (save-excursion
898				   ;; If the file begins with "#!"
899				   ;; (exec interpreter magic), look
900				   ;; for mode frobs in the first two
901				   ;; lines.  You cannot necessarily
902				   ;; put them in the first line of
903				   ;; such a file without screwing up
904				   ;; the interpreter invocation.
905				   (end-of-line (and (looking-at "^#!") 2))
906				   (point)) t)
907	   (progn
908	     (skip-chars-forward " \t")
909	     (setq beg (point))
910	     (search-forward "-*-"
911			     (save-excursion (end-of-line) (point))
912			     t))
913	   (progn
914	     (forward-char -3)
915	     (skip-chars-backward " \t")
916	     (setq end (point))
917	     (goto-char beg)
918	     (if (save-excursion (search-forward ":" end t))
919		 ;; Find all specifications for the `mode:' variable
920		 ;; and execute them left to right.
921		 (while (let ((case-fold-search t))
922			  (search-forward "mode:" end t))
923		   (skip-chars-forward " \t")
924		   (setq beg (point))
925		   (if (search-forward ";" end t)
926		       (forward-char -1)
927		     (goto-char end))
928		   (skip-chars-backward " \t")
929		   (funcall (intern (concat (downcase (buffer-substring beg (point))) "-mode"))))
930	       ;; Simple -*-MODE-*- case.
931	       (funcall (intern (concat (downcase (buffer-substring beg end)) "-mode"))))
932	     (setq done t)))
933      ;; If we didn't find a mode from a -*- line, try using the file name.
934      (if (and (not done) buffer-file-name)
935	  (let ((name buffer-file-name)
936		(case-fold-search (eq system-type 'vax-vms))
937		(keep-going t))
938	    ;; Remove backup-suffixes from file name.
939	    (setq name (file-name-sans-versions name))
940	    (while keep-going
941	      (setq keep-going nil)
942	      (let ((alist auto-mode-alist)
943		    (mode nil))
944		;; Find first matching alist entry.
945		(while (and (not mode) alist)
946		  (if (string-match (car (car alist)) name)
947		      (if (and (consp (cdr (car alist)))
948			       (nth 2 (car alist)))
949			  (progn
950			    (setq mode (car (cdr (car alist)))
951				  name (substring name 0 (match-beginning 0))
952				  keep-going t))
953			(setq mode (cdr (car alist))
954			      keep-going nil)))
955		  (setq alist (cdr alist)))
956		(if mode
957		    (funcall mode)
958		  ;; If we can't deduce a mode from the file name,
959		  ;; look for an interpreter specified in the first line.
960		  (let ((interpreter
961			 (save-excursion
962			   (goto-char (point-min))
963			   (if (looking-at "#! *\\([^ \t\n]+\\)")
964			       (buffer-substring (match-beginning 1)
965						 (match-end 1))
966			     "")))
967			elt)
968		    ;; Map interpreter name to a mode.
969		    (setq elt (assoc (file-name-nondirectory interpreter)
970				     interpreter-mode-alist))
971		    (if elt
972			(funcall (cdr elt))))))))))))
973
974(defun hack-local-variables-prop-line ()
975  ;; Set local variables specified in the -*- line.
976  ;; Ignore any specification for `mode:';
977  ;; set-auto-mode should already have handled that.
978  (save-excursion
979    (goto-char (point-min))
980    (let ((result nil)
981	  (end (save-excursion (end-of-line (and (looking-at "^#!") 2)) (point))))
982      ;; Parse the -*- line into the `result' alist.
983      (cond ((not (search-forward "-*-" end t))
984	     ;; doesn't have one.
985	     nil)
986	    ((looking-at "[ \t]*\\([^ \t\n\r:;]+\\)\\([ \t]*-\\*-\\)")
987	     ;; Simple form: "-*- MODENAME -*-".  Already handled.
988	     nil)
989	    (t
990	     ;; Hairy form: '-*-' [ <variable> ':' <value> ';' ]* '-*-'
991	     ;; (last ";" is optional).
992	     (save-excursion
993	       (if (search-forward "-*-" end t)
994		   (setq end (- (point) 3))
995		 (error "-*- not terminated before end of line")))
996	     (while (< (point) end)
997	       (or (looking-at "[ \t]*\\([^ \t\n:]+\\)[ \t]*:[ \t]*")
998		   (error "malformed -*- line"))
999	       (goto-char (match-end 0))
1000	       (let ((key (intern (downcase (buffer-substring
1001					     (match-beginning 1)
1002					     (match-end 1)))))
1003		     (val (save-restriction
1004			    (narrow-to-region (point) end)
1005			    (read (current-buffer)))))
1006		 (or (eq key 'mode)
1007		     (setq result (cons (cons key val) result)))
1008		 (skip-chars-forward " \t;")))
1009	     (setq result (nreverse result))))
1010
1011      (if (and result
1012	       (or (eq enable-local-variables t)
1013		   (and enable-local-variables
1014			(save-window-excursion
1015			  (condition-case nil
1016			      (switch-to-buffer (current-buffer))
1017			    (error
1018			     ;; If we fail to switch in the selected window,
1019			     ;; it is probably a minibuffer.
1020			     ;; So try another window.
1021			     (condition-case nil
1022				 (switch-to-buffer-other-window (current-buffer))
1023			       (error
1024				(switch-to-buffer-other-frame (current-buffer))))))
1025			  (y-or-n-p (format "Set local variables as specified in -*- line of %s? "
1026					    (file-name-nondirectory buffer-file-name)))))))
1027	  (while result
1028	    (hack-one-local-variable (car (car result)) (cdr (car result)))
1029	    (setq result (cdr result)))))))
1030
1031(defun hack-local-variables ()
1032  "Parse and put into effect this buffer's local variables spec."
1033  (hack-local-variables-prop-line)
1034  ;; Look for "Local variables:" line in last page.
1035  (save-excursion
1036    (goto-char (point-max))
1037    (search-backward "\n\^L" (max (- (point-max) 3000) (point-min)) 'move)
1038    (if (let ((case-fold-search t))
1039	  (and (search-forward "Local Variables:" nil t)
1040	       (or (eq enable-local-variables t)
1041		   (and enable-local-variables
1042			(save-window-excursion
1043			  (switch-to-buffer (current-buffer))
1044			  (save-excursion
1045			    (beginning-of-line)
1046			    (set-window-start (selected-window) (point)))
1047			  (y-or-n-p (format "Set local variables as specified at end of %s? "
1048 					    (if buffer-file-name
1049 						(file-name-nondirectory
1050 						 buffer-file-name)
1051 					      (concat "buffer "
1052 						      (buffer-name))))))))))
1053	(let ((continue t)
1054	      prefix prefixlen suffix beg
1055	      (enable-local-eval enable-local-eval))
1056	  ;; The prefix is what comes before "local variables:" in its line.
1057	  ;; The suffix is what comes after "local variables:" in its line.
1058	  (skip-chars-forward " \t")
1059	  (or (eolp)
1060	      (setq suffix (buffer-substring (point)
1061					     (progn (end-of-line) (point)))))
1062	  (goto-char (match-beginning 0))
1063	  (or (bolp)
1064	      (setq prefix
1065		    (buffer-substring (point)
1066				      (progn (beginning-of-line) (point)))))
1067
1068	  (if prefix (setq prefixlen (length prefix)
1069			   prefix (regexp-quote prefix)))
1070	  (if suffix (setq suffix (concat (regexp-quote suffix) "$")))
1071	  (while continue
1072	    ;; Look at next local variable spec.
1073	    (if selective-display (re-search-forward "[\n\C-m]")
1074	      (forward-line 1))
1075	    ;; Skip the prefix, if any.
1076	    (if prefix
1077		(if (looking-at prefix)
1078		    (forward-char prefixlen)
1079		  (error "Local variables entry is missing the prefix")))
1080	    ;; Find the variable name; strip whitespace.
1081	    (skip-chars-forward " \t")
1082	    (setq beg (point))
1083	    (skip-chars-forward "^:\n")
1084	    (if (eolp) (error "Missing colon in local variables entry"))
1085	    (skip-chars-backward " \t")
1086	    (let* ((str (buffer-substring beg (point)))
1087		   (var (read str))
1088		  val)
1089	      ;; Setting variable named "end" means end of list.
1090	      (if (string-equal (downcase str) "end")
1091		  (setq continue nil)
1092		;; Otherwise read the variable value.
1093		(skip-chars-forward "^:")
1094		(forward-char 1)
1095		(setq val (read (current-buffer)))
1096		(skip-chars-backward "\n")
1097		(skip-chars-forward " \t")
1098		(or (if suffix (looking-at suffix) (eolp))
1099		    (error "Local variables entry is terminated incorrectly"))
1100		;; Set the variable.  "Variables" mode and eval are funny.
1101		(hack-one-local-variable var val))))))))
1102
1103(defconst ignored-local-variables
1104  '(enable-local-eval)
1105  "Variables to be ignored in a file's local variable spec.")
1106
1107;; Get confirmation before setting these variables as locals in a file.
1108(put 'enable-local-eval 'risky-local-variable t)
1109(put 'eval 'risky-local-variable t)
1110(put 'file-name-handler-alist 'risky-local-variable t)
1111(put 'minor-mode-map-alist 'risky-local-variable t)
1112(put 'after-load-alist 'risky-local-variable t)
1113(put 'buffer-file-name 'risky-local-variable t)
1114(put 'buffer-auto-save-file-name 'risky-local-variable t)
1115(put 'buffer-file-truename 'risky-local-variable t)
1116
1117(defun hack-one-local-variable-quotep (exp)
1118  (and (consp exp) (eq (car exp) 'quote) (consp (cdr exp))))
1119
1120;; "Set" one variable in a local variables spec.
1121;; A few variable names are treated specially.
1122(defun hack-one-local-variable (var val)
1123  (cond ((eq var 'mode)
1124	 (funcall (intern (concat (downcase (symbol-name val))
1125				  "-mode"))))
1126	((memq var ignored-local-variables)
1127	 nil)
1128	;; "Setting" eval means either eval it or do nothing.
1129	;; Likewise for setting hook variables.
1130	((or (get var 'risky-local-variable)
1131	     (string-match "-hooks?$\\|-functions?$\\|-forms?$"
1132			   (symbol-name var)))
1133	 ;; Permit evaling a put of a harmless property
1134	 ;; if the args do nothing tricky.
1135	 (if (or (and (eq var 'eval)
1136		      (consp val)
1137		      (eq (car val) 'put)
1138		      (hack-one-local-variable-quotep (nth 1 val))
1139		      (hack-one-local-variable-quotep (nth 2 val))
1140		      ;; Only allow safe values of lisp-indent-hook;
1141		      ;; not functions.
1142		      (or (numberp (nth 3 val))
1143			  (equal (nth 3 val) ''defun))
1144		      (memq (nth 1 (nth 2 val))
1145			    '(lisp-indent-hook)))
1146		 ;; Permit eval if not root and user says ok.
1147		 (and (not (string= (user-login-name) "root"))
1148		      (or (eq enable-local-eval t)
1149			  (and enable-local-eval
1150			       (save-window-excursion
1151				 (switch-to-buffer (current-buffer))
1152				 (save-excursion
1153				   (beginning-of-line)
1154				   (set-window-start (selected-window) (point)))
1155				 (setq enable-local-eval
1156				       (y-or-n-p (format "Process `eval' or hook local variables in file %s? "
1157							 (file-name-nondirectory buffer-file-name)))))))))
1158	     (if (eq var 'eval)
1159		 (save-excursion (eval val))
1160	       (make-local-variable var)
1161	       (set var val))
1162	   (message "Ignoring `eval:' in file's local variables")))
1163	;; Ordinary variable, really set it.
1164	(t (make-local-variable var)
1165	   (set var val))))
1166
1167
1168(defun set-visited-file-name (filename)
1169  "Change name of file visited in current buffer to FILENAME.
1170The next time the buffer is saved it will go in the newly specified file.
1171nil or empty string as argument means make buffer not be visiting any file.
1172Remember to delete the initial contents of the minibuffer
1173if you wish to pass an empty string as the argument."
1174  (interactive "FSet visited file name: ")
1175  (if filename
1176      (setq filename
1177	    (if (string-equal filename "")
1178		nil
1179	      (expand-file-name filename))))
1180  (or (equal filename buffer-file-name)
1181      (progn
1182	(and filename (lock-buffer filename))
1183	(unlock-buffer)))
1184  (setq buffer-file-name filename)
1185  (if filename				; make buffer name reflect filename.
1186      (let ((new-name (file-name-nondirectory buffer-file-name)))
1187	(if (string= new-name "")
1188	    (error "Empty file name"))
1189	(if (eq system-type 'vax-vms)
1190	    (setq new-name (downcase new-name)))
1191	(setq default-directory (file-name-directory buffer-file-name))
1192	(or (string= new-name (buffer-name))
1193	    (rename-buffer new-name t))))
1194  (setq buffer-backed-up nil)
1195  (clear-visited-file-modtime)
1196  (if filename
1197      (progn
1198	(setq buffer-file-truename
1199	      (abbreviate-file-name (file-truename buffer-file-name)))
1200	(if find-file-visit-truename
1201	    (setq buffer-file-name buffer-file-truename))
1202	(setq buffer-file-number (nth 10 (file-attributes buffer-file-name))))
1203    (setq buffer-file-truename nil buffer-file-number nil))
1204  ;; write-file-hooks is normally used for things like ftp-find-file
1205  ;; that visit things that are not local files as if they were files.
1206  ;; Changing to visit an ordinary local file instead should flush the hook.
1207  (kill-local-variable 'write-file-hooks)
1208  (kill-local-variable 'local-write-file-hooks)
1209  (kill-local-variable 'revert-buffer-function)
1210  (kill-local-variable 'backup-inhibited)
1211  ;; If buffer was read-only because of version control,
1212  ;; that reason is gone now, so make it writable.
1213  (if vc-mode
1214      (setq buffer-read-only nil))
1215  (kill-local-variable 'vc-mode)
1216  ;; Turn off backup files for certain file names.
1217  ;; Since this is a permanent local, the major mode won't eliminate it.
1218  (and (not (funcall backup-enable-predicate buffer-file-name))
1219       (progn
1220	 (make-local-variable 'backup-inhibited)
1221	 (setq backup-inhibited t)))
1222  (let ((oauto buffer-auto-save-file-name))
1223    ;; If auto-save was not already on, turn it on if appropriate.
1224    (if (not buffer-auto-save-file-name)
1225	(and buffer-file-name auto-save-default
1226	     (auto-save-mode t))
1227      ;; If auto save is on, start using a new name.
1228      ;; We deliberately don't rename or delete the old auto save
1229      ;; for the old visited file name.  This is because perhaps
1230      ;; the user wants to save the new state and then compare with the
1231      ;; previous state from the auto save file.
1232      (setq buffer-auto-save-file-name
1233	    (make-auto-save-file-name)))
1234    ;; Rename the old auto save file if any.
1235    (and oauto buffer-auto-save-file-name
1236	 (file-exists-p oauto)
1237	 (rename-file oauto buffer-auto-save-file-name t)))
1238  (if buffer-file-name
1239      (set-buffer-modified-p t)))
1240
1241(defun write-file (filename)
1242  "Write current buffer into file FILENAME.
1243Makes buffer visit that file, and marks it not modified.
1244If the buffer is already visiting a file, you can specify
1245a directory name as FILENAME, to write a file of the same
1246old name in that directory."
1247;;  (interactive "FWrite file: ")
1248  (interactive
1249   (list (if buffer-file-name
1250	     (read-file-name "Write file: "
1251				 nil nil nil nil)
1252	   (read-file-name "Write file: "
1253			       (cdr (assq 'default-directory
1254					  (buffer-local-variables)))
1255			       nil nil (buffer-name)))))
1256  (or (null filename) (string-equal filename "")
1257      (progn
1258	;; If arg is just a directory,
1259	;; use same file name, but in that directory.
1260	(if (and (file-directory-p filename) buffer-file-name)
1261	    (setq filename (concat (file-name-as-directory filename)
1262				   (file-name-nondirectory buffer-file-name))))
1263	(set-visited-file-name filename)))
1264  (set-buffer-modified-p t)
1265  (save-buffer))
1266
1267(defun backup-buffer ()
1268  "Make a backup of the disk file visited by the current buffer, if appropriate.
1269This is normally done before saving the buffer the first time.
1270If the value is non-nil, it is the result of `file-modes' on the original
1271file; this means that the caller, after saving the buffer, should change
1272the modes of the new file to agree with the old modes."
1273  (if (and make-backup-files (not backup-inhibited)
1274	   (not buffer-backed-up)
1275	   (file-exists-p buffer-file-name)
1276	   (memq (aref (elt (file-attributes buffer-file-name) 8) 0)
1277		 '(?- ?l)))
1278      (let ((real-file-name buffer-file-name)
1279	    backup-info backupname targets setmodes)
1280	;; If specified name is a symbolic link, chase it to the target.
1281	;; Thus we make the backups in the directory where the real file is.
1282	(setq real-file-name (file-chase-links real-file-name))
1283	(setq backup-info (find-backup-file-name real-file-name)
1284	      backupname (car backup-info)
1285	      targets (cdr backup-info))
1286;;;     (if (file-directory-p buffer-file-name)
1287;;;         (error "Cannot save buffer in directory %s" buffer-file-name))
1288        (condition-case ()
1289	    (let ((delete-old-versions
1290		   ;; If have old versions to maybe delete,
1291		   ;; ask the user to confirm now, before doing anything.
1292		   ;; But don't actually delete til later.
1293		   (and targets
1294			(or (eq trim-versions-without-asking t) (eq trim-versions-without-asking nil))
1295			(or trim-versions-without-asking
1296			    (y-or-n-p (format "Delete excess backup versions of %s? "
1297					      real-file-name))))))
1298	      ;; Actually write the back up file.
1299	      (condition-case ()
1300		  (if (or file-precious-flag
1301;			  (file-symlink-p buffer-file-name)
1302			  backup-by-copying
1303			  (and backup-by-copying-when-linked
1304			       (> (file-nlinks real-file-name) 1))
1305			  (and backup-by-copying-when-mismatch
1306			       (let ((attr (file-attributes real-file-name)))
1307				 (or (nth 9 attr)
1308				     (/= (nth 2 attr) (user-uid))))))
1309		      (condition-case ()
1310			  (copy-file real-file-name backupname t t)
1311			(file-error
1312			 ;; If copying fails because file BACKUPNAME
1313			 ;; is not writable, delete that file and try again.
1314			 (if (and (file-exists-p backupname)
1315				  (not (file-writable-p backupname)))
1316			     (delete-file backupname))
1317			 (copy-file real-file-name backupname t t)))
1318		    ;; rename-file should delete old backup.
1319		    (rename-file real-file-name backupname t)
1320		    (setq setmodes (file-modes backupname)))
1321		(file-error
1322		 ;; If trouble writing the backup, write it in ~.
1323		 (setq backupname (expand-file-name "~/%backup%~"))
1324		 (message "Cannot write backup file; backing up in ~/%%backup%%~")
1325		 (sleep-for 1)
1326		 (condition-case ()
1327		     (copy-file real-file-name backupname t t)
1328		   (file-error
1329		    ;; If copying fails because file BACKUPNAME
1330		    ;; is not writable, delete that file and try again.
1331		    (if (and (file-exists-p backupname)
1332			     (not (file-writable-p backupname)))
1333			(delete-file backupname))
1334		    (copy-file real-file-name backupname t t)))))
1335	      (setq buffer-backed-up t)
1336	      ;; Now delete the old versions, if desired.
1337	      (if delete-old-versions
1338		  (while targets
1339		    (condition-case ()
1340			(delete-file (car targets))
1341		      (file-error nil))
1342		    (setq targets (cdr targets))))
1343	      setmodes)
1344	(file-error nil)))))
1345
1346(defun file-name-sans-versions (name &optional keep-backup-version)
1347  "Return FILENAME sans backup versions or strings.
1348This is a separate procedure so your site-init or startup file can
1349redefine it.
1350If the optional argument KEEP-BACKUP-VERSION is non-nil,
1351we do not remove backup version numbers, only true file version numbers."
1352  (let ((handler (find-file-name-handler name 'file-name-sans-versions)))
1353    (if handler
1354	(funcall handler 'file-name-sans-versions name keep-backup-version)
1355      (substring name 0
1356		 (if (eq system-type 'vax-vms)
1357		     ;; VMS version number is (a) semicolon, optional
1358		     ;; sign, zero or more digits or (b) period, option
1359		     ;; sign, zero or more digits, provided this is the
1360		     ;; second period encountered outside of the
1361		     ;; device/directory part of the file name.
1362		     (or (string-match ";[-+]?[0-9]*\\'" name)
1363			 (if (string-match "\\.[^]>:]*\\(\\.[-+]?[0-9]*\\)\\'"
1364					   name)
1365			     (match-beginning 1))
1366			 (length name))
1367		   (if keep-backup-version
1368		       (length name)
1369		     (or (string-match "\\.~[0-9]+~\\'" name)
1370			 (string-match "~\\'" name)
1371			 (length name))))))))
1372
1373(defun make-backup-file-name (file)
1374  "Create the non-numeric backup file name for FILE.
1375This is a separate function so you can redefine it for customization."
1376  (if (eq system-type 'ms-dos)
1377      (let ((fn (file-name-nondirectory file)))
1378	(concat (file-name-directory file)
1379		(if (string-match "\\([^.]*\\)\\(\\..*\\)?" fn)
1380		    (substring fn 0 (match-end 1)))
1381		".bak"))
1382    (concat file "~")))
1383
1384(defun backup-file-name-p (file)
1385  "Return non-nil if FILE is a backup file name (numeric or not).
1386This is a separate function so you can redefine it for customization.
1387You may need to redefine `file-name-sans-versions' as well."
1388  (if (eq system-type 'ms-dos)
1389      (string-match "\\.bak$" file)
1390    (string-match "~$" file)))
1391
1392;; This is used in various files.
1393;; The usage of bv-length is not very clean,
1394;; but I can't see a good alternative,
1395;; so as of now I am leaving it alone.
1396(defun backup-extract-version (fn)
1397  "Given the name of a numeric backup file, return the backup number.
1398Uses the free variable `bv-length', whose value should be
1399the index in the name where the version number begins."
1400  (if (and (string-match "[0-9]+~$" fn bv-length)
1401	   (= (match-beginning 0) bv-length))
1402      (string-to-int (substring fn bv-length -1))
1403      0))
1404
1405;; I believe there is no need to alter this behavior for VMS;
1406;; since backup files are not made on VMS, it should not get called.
1407(defun find-backup-file-name (fn)
1408  "Find a file name for a backup file, and suggestions for deletions.
1409Value is a list whose car is the name for the backup file
1410 and whose cdr is a list of old versions to consider deleting now."
1411  (if (eq version-control 'never)
1412      (list (make-backup-file-name fn))
1413    (let* ((base-versions (concat (file-name-nondirectory fn) ".~"))
1414	   (bv-length (length base-versions))
1415	   possibilities
1416	   (versions nil)
1417	   (high-water-mark 0)
1418	   (deserve-versions-p nil)
1419	   (number-to-delete 0))
1420      (condition-case ()
1421	  (setq possibilities (file-name-all-completions
1422			       base-versions
1423			       (file-name-directory fn))
1424		versions (sort (mapcar
1425				(function backup-extract-version)
1426				possibilities)
1427			       '<)
1428		high-water-mark (apply 'max 0 versions)
1429		deserve-versions-p (or version-control
1430				       (> high-water-mark 0))
1431		number-to-delete (- (length versions)
1432				    kept-old-versions kept-new-versions -1))
1433	(file-error
1434	 (setq possibilities nil)))
1435      (if (not deserve-versions-p)
1436	  (list (make-backup-file-name fn))
1437	(cons (concat fn ".~" (int-to-string (1+ high-water-mark)) "~")
1438	      (if (and (> number-to-delete 0)
1439                       ;; Delete nothing if there is overflow
1440		       ;; in the number of versions to keep.
1441		       (>= (+ kept-new-versions kept-old-versions -1) 0))
1442		  (mapcar (function (lambda (n)
1443				      (concat fn ".~" (int-to-string n) "~")))
1444			  (let ((v (nthcdr kept-old-versions versions)))
1445			    (rplacd (nthcdr (1- number-to-delete) v) ())
1446			    v))))))))
1447
1448(defun file-nlinks (filename)
1449  "Return number of names file FILENAME has."
1450  (car (cdr (file-attributes filename))))
1451
1452(defun file-relative-name (filename &optional directory)
1453  "Convert FILENAME to be relative to DIRECTORY (default: default-directory)."
1454  (setq filename (expand-file-name filename)
1455	directory (file-name-as-directory (expand-file-name
1456					   (or directory default-directory))))
1457  (let ((ancestor ""))
1458    (while (not (string-match (concat "^" (regexp-quote directory)) filename))
1459      (setq directory (file-name-directory (substring directory 0 -1))
1460	    ancestor (concat "../" ancestor)))
1461    (concat ancestor (substring filename (match-end 0)))))
1462
1463(defun save-buffer (&optional args)
1464  "Save current buffer in visited file if modified.  Versions described below.
1465By default, makes the previous version into a backup file
1466 if previously requested or if this is the first save.
1467With 1 or 3 \\[universal-argument]'s, marks this version
1468 to become a backup when the next save is done.
1469With 2 or 3 \\[universal-argument]'s,
1470 unconditionally makes the previous version into a backup file.
1471With argument of 0, never makes the previous version into a backup file.
1472
1473If a file's name is FOO, the names of its numbered backup versions are
1474 FOO.~i~ for various integers i.  A non-numbered backup file is called FOO~.
1475Numeric backups (rather than FOO~) will be made if value of
1476 `version-control' is not the atom `never' and either there are already
1477 numeric versions of the file being backed up, or `version-control' is
1478 non-nil.
1479We don't want excessive versions piling up, so there are variables
1480 `kept-old-versions', which tells Emacs how many oldest versions to keep,
1481 and `kept-new-versions', which tells how many newest versions to keep.
1482 Defaults are 2 old versions and 2 new.
1483`dired-kept-versions' controls dired's clean-directory (.) command.
1484If `trim-versions-without-asking' is nil, system will query user
1485 before trimming versions.  Otherwise it does it silently."
1486  (interactive "p")
1487  (let ((modp (buffer-modified-p))
1488	(large (> (buffer-size) 50000))
1489	(make-backup-files (and make-backup-files (not (eq args 0)))))
1490    (and modp (memq args '(16 64)) (setq buffer-backed-up nil))
1491    (if (and modp large) (message "Saving file %s..." (buffer-file-name)))
1492    (basic-save-buffer)
1493    (and modp (memq args '(4 64)) (setq buffer-backed-up nil))))
1494
1495(defun delete-auto-save-file-if-necessary (&optional force)
1496  "Delete auto-save file for current buffer if `delete-auto-save-files' is t.
1497Normally delete only if the file was written by this Emacs since
1498the last real save, but optional arg FORCE non-nil means delete anyway."
1499  (and buffer-auto-save-file-name delete-auto-save-files
1500       (not (string= buffer-file-name buffer-auto-save-file-name))
1501       (or force (recent-auto-save-p))
1502       (progn
1503	 (condition-case ()
1504	     (delete-file buffer-auto-save-file-name)
1505	   (file-error nil))
1506	 (set-buffer-auto-saved))))
1507
1508(defun basic-save-buffer ()
1509  "Save the current buffer in its visited file, if it has been modified."
1510  (interactive)
1511  (if (buffer-modified-p)
1512      (let ((recent-save (recent-auto-save-p))
1513	    setmodes tempsetmodes)
1514	;; On VMS, rename file and buffer to get rid of version number.
1515	(if (and (eq system-type 'vax-vms)
1516		 (not (string= buffer-file-name
1517			       (file-name-sans-versions buffer-file-name))))
1518	    (let (buffer-new-name)
1519	      ;; Strip VMS version number before save.
1520	      (setq buffer-file-name
1521		    (file-name-sans-versions buffer-file-name))
1522	      ;; Construct a (unique) buffer name to correspond.
1523	      (let ((buf (create-file-buffer (downcase buffer-file-name))))
1524		(setq buffer-new-name (buffer-name buf))
1525		(kill-buffer buf))
1526	      (rename-buffer buffer-new-name)))
1527	;; If buffer has no file name, ask user for one.
1528	(or buffer-file-name
1529	    (set-visited-file-name
1530	     (expand-file-name (read-file-name "File to save in: ") nil)))
1531	(or (verify-visited-file-modtime (current-buffer))
1532	    (not (file-exists-p buffer-file-name))
1533	    (yes-or-no-p
1534	     (format "%s has changed since visited or saved.  Save anyway? "
1535		     (file-name-nondirectory buffer-file-name)))
1536	    (error "Save not confirmed"))
1537	(save-restriction
1538	  (widen)
1539	  (and (> (point-max) 1)
1540	       (/= (char-after (1- (point-max))) ?\n)
1541	       (not (and (eq selective-display t)
1542			 (= (char-after (1- (point-max))) ?\r)))
1543	       (or (eq require-final-newline t)
1544		   (and require-final-newline
1545			(y-or-n-p
1546			 (format "Buffer %s does not end in newline.  Add one? "
1547				 (buffer-name)))))
1548	       (save-excursion
1549		 (goto-char (point-max))
1550		 (insert ?\n)))
1551	  (let ((hooks (append write-contents-hooks local-write-file-hooks
1552			       write-file-hooks))
1553		(done nil))
1554	    (while (and hooks
1555			(not (setq done (funcall (car hooks)))))
1556	      (setq hooks (cdr hooks)))
1557	    ;; If a hook returned t, file is already "written".
1558	    (cond ((not done)
1559		   (setq setmodes (basic-save-buffer-1)))))
1560	  (setq buffer-file-number (nth 10 (file-attributes buffer-file-name)))
1561	  (if setmodes
1562	      (condition-case ()
1563		  (set-file-modes buffer-file-name setmodes)
1564		(error nil))))
1565	;; If the auto-save file was recent before this command,
1566	;; delete it now.
1567	(delete-auto-save-file-if-necessary recent-save)
1568	(run-hooks 'after-save-hook))
1569    (message "(No changes need to be saved)")))
1570
1571;; This does the "real job" of writing a buffer into its visited file
1572;; and making a backup file.  This is what is normally done
1573;; but inhibited if one of write-file-hooks returns non-nil.
1574;; It returns a value to store in setmodes.
1575(defun basic-save-buffer-1 ()
1576  (let (tempsetmodes setmodes)
1577    (if (not (file-writable-p buffer-file-name))
1578	(let ((dir (file-name-directory buffer-file-name)))
1579	  (if (not (file-directory-p dir))
1580	      (error "%s is not a directory" dir)
1581	    (if (not (file-exists-p buffer-file-name))
1582		(error "Directory %s write-protected" dir)
1583	      (if (yes-or-no-p
1584		   (format "File %s is write-protected; try to save anyway? "
1585			   (file-name-nondirectory
1586			    buffer-file-name)))
1587		  (setq tempsetmodes t)
1588		(error "Attempt to save to a file which you aren't allowed to write"))))))
1589    (or buffer-backed-up
1590	(setq setmodes (backup-buffer)))
1591    (if file-precious-flag
1592	;; If file is precious, write temp name, then rename it.
1593	(let ((dir (file-name-directory buffer-file-name))
1594	      (realname buffer-file-name)
1595	      tempname temp nogood i succeed)
1596	  (setq i 0)
1597	  (setq nogood t)
1598	  ;; Find the temporary name to write under.
1599	  (while nogood
1600	    (setq tempname (format "%s#tmp#%d" dir i))
1601	    (setq nogood (file-exists-p tempname))
1602	    (setq i (1+ i)))
1603	  (unwind-protect
1604	      (progn (clear-visited-file-modtime)
1605		     (write-region (point-min) (point-max)
1606				   tempname nil realname)
1607		     (setq succeed t))
1608	    ;; If writing the temp file fails,
1609	    ;; delete the temp file.
1610	    (or succeed (delete-file tempname)))
1611	  ;; Since we have created an entirely new file
1612	  ;; and renamed it, make sure it gets the
1613	  ;; right permission bits set.
1614	  (setq setmodes (file-modes buffer-file-name))
1615	  ;; We succeeded in writing the temp file,
1616	  ;; so rename it.
1617	  (rename-file tempname buffer-file-name t))
1618      ;; If file not writable, see if we can make it writable
1619      ;; temporarily while we write it.
1620      ;; But no need to do so if we have just backed it up
1621      ;; (setmodes is set) because that says we're superseding.
1622      (cond ((and tempsetmodes (not setmodes))
1623	     ;; Change the mode back, after writing.
1624	     (setq setmodes (file-modes buffer-file-name))
1625	     (set-file-modes buffer-file-name 511)))
1626      (write-region (point-min) (point-max)
1627		    buffer-file-name nil t))
1628    setmodes))
1629
1630(defun save-some-buffers (&optional arg exiting)
1631  "Save some modified file-visiting buffers.  Asks user about each one.
1632Optional argument (the prefix) non-nil means save all with no questions.
1633Optional second argument EXITING means ask about certain non-file buffers
1634 as well as about file buffers."
1635  (interactive "P")
1636  (save-window-excursion
1637    (let ((files-done
1638	   (map-y-or-n-p
1639	    (function
1640	     (lambda (buffer)
1641	       (and (buffer-modified-p buffer)
1642		    (or
1643		     (buffer-file-name buffer)
1644		     (and exiting
1645			  (progn
1646			    (set-buffer buffer)
1647			    (and buffer-offer-save (> (buffer-size) 0)))))
1648		    (if arg
1649			t
1650		      (if (buffer-file-name buffer)
1651			  (format "Save file %s? "
1652				  (buffer-file-name buffer))
1653			(format "Save buffer %s? "
1654				(buffer-name buffer)))))))
1655	    (function
1656	     (lambda (buffer)
1657	       (set-buffer buffer)
1658	       (save-buffer)))
1659	    (buffer-list)
1660	    '("buffer" "buffers" "save")
1661	    (list (list ?\C-r (lambda (buf)
1662				(view-buffer buf)
1663				(setq view-exit-action
1664				      '(lambda (ignore)
1665					 (exit-recursive-edit)))
1666				(recursive-edit)
1667				;; Return nil to ask about BUF again.
1668				nil)
1669			"display the current buffer"))))
1670	  (abbrevs-done
1671	   (and save-abbrevs abbrevs-changed
1672		(progn
1673		  (if (or arg
1674			  (y-or-n-p (format "Save abbrevs in %s? " abbrev-file-name)))
1675		      (write-abbrev-file nil))
1676		  ;; Don't keep bothering user if he says no.
1677		  (setq abbrevs-changed nil)
1678		  t))))
1679      (or (> files-done 0) abbrevs-done
1680	  (message "(No files need saving)")))))
1681
1682(defun not-modified (&optional arg)
1683  "Mark current buffer as unmodified, not needing to be saved.
1684With prefix arg, mark buffer as modified, so \\[save-buffer] will save."
1685  (interactive "P")
1686  (message (if arg "Modification-flag set"
1687	       "Modification-flag cleared"))
1688  (set-buffer-modified-p arg))
1689
1690(defun toggle-read-only (&optional arg)
1691  "Change whether this buffer is visiting its file read-only.
1692With arg, set read-only iff arg is positive."
1693  (interactive "P")
1694  (setq buffer-read-only
1695	(if (null arg)
1696            (not buffer-read-only)
1697            (> (prefix-numeric-value arg) 0)))
1698  ;; Force mode-line redisplay
1699  (set-buffer-modified-p (buffer-modified-p)))
1700
1701(defun insert-file (filename)
1702  "Insert contents of file FILENAME into buffer after point.
1703Set mark after the inserted text.
1704
1705This function is meant for the user to run interactively.
1706Don't call it from programs!  Use `insert-file-contents' instead.
1707\(Its calling sequence is different; see its documentation)."
1708  (interactive "*fInsert file: ")
1709  (if (file-directory-p filename)
1710      (signal 'file-error (list "Opening input file" "file is a directory"
1711				filename)))
1712  (let ((tem (insert-file-contents filename)))
1713    (push-mark (+ (point) (car (cdr tem))))))
1714
1715(defun append-to-file (start end filename)
1716  "Append the contents of the region to the end of file FILENAME.
1717When called from a function, expects three arguments,
1718START, END and FILENAME.  START and END are buffer positions
1719saying what text to write."
1720  (interactive "r\nFAppend to file: ")
1721  (write-region start end filename t))
1722
1723(defun file-newest-backup (filename)
1724  "Return most recent backup file for FILENAME or nil if no backups exist."
1725  (let* ((filename (expand-file-name filename))
1726	 (file (file-name-nondirectory filename))
1727	 (dir  (file-name-directory    filename))
1728	 (comp (file-name-all-completions file dir))
1729	 newest)
1730    (while comp
1731      (setq file (concat dir (car comp))
1732	    comp (cdr comp))
1733      (if (and (backup-file-name-p file)
1734	       (or (null newest) (file-newer-than-file-p file newest)))
1735	  (setq newest file)))
1736    newest))
1737
1738(defun rename-uniquely ()
1739  "Rename current buffer to a similar name not already taken.
1740This function is useful for creating multiple shell process buffers
1741or multiple mail buffers, etc."
1742  (interactive)
1743  (let* ((new-buf (generate-new-buffer (buffer-name)))
1744	 (name (buffer-name new-buf)))
1745    (kill-buffer new-buf)
1746    (rename-buffer name)
1747    (set-buffer-modified-p (buffer-modified-p)))) ; force mode line update
1748
1749(defun make-directory (dir &optional parents)
1750  "Create the directory DIR and any nonexistent parent dirs.
1751Interactively, the default choice of directory to create
1752is the current default directory for file names.
1753That is useful when you have visited a file in a nonexistint directory.
1754
1755Noninteractively, the second (optional) argument PARENTS says whether
1756to create parent directories if they don't exist."
1757  (interactive
1758   (list (read-file-name "Make directory: " default-directory default-directory
1759			 nil nil)
1760	 t))
1761  (let ((handler (find-file-name-handler dir 'make-directory)))
1762    (if handler
1763	(funcall handler 'make-directory dir parents)
1764      (if (not parents)
1765	  (make-directory-internal dir)
1766	(let ((dir (directory-file-name (expand-file-name dir)))
1767	      create-list)
1768	  (while (not (file-exists-p dir))
1769	    (setq create-list (cons dir create-list)
1770		  dir (directory-file-name (file-name-directory dir))))
1771	  (while create-list
1772	    (make-directory-internal (car create-list))
1773	    (setq create-list (cdr create-list))))))))
1774
1775(put 'revert-buffer-function 'permanent-local t)
1776(defvar revert-buffer-function nil
1777  "Function to use to revert this buffer, or nil to do the default.")
1778
1779(put 'revert-buffer-insert-file-contents-function 'permanent-local t)
1780(defvar revert-buffer-insert-file-contents-function nil
1781  "Function to use to insert contents when reverting this buffer.
1782Gets two args, first the nominal file name to use,
1783and second, t if reading the auto-save file.")
1784
1785(defun revert-buffer (&optional ignore-auto noconfirm)
1786  "Replace the buffer text with the text of the visited file on disk.
1787This undoes all changes since the file was visited or saved.
1788With a prefix argument, offer to revert from latest auto-save file, if
1789that is more recent than the visited file.
1790
1791When called from lisp, The first argument is IGNORE-AUTO; only offer
1792to revert from the auto-save file when this is nil.  Note that the
1793sense of this argument is the reverse of the prefix argument, for the
1794sake of backward compatibility.  IGNORE-AUTO is optional, defaulting
1795to nil.
1796
1797Optional second argument NOCONFIRM means don't ask for confirmation at
1798all.
1799
1800If the value of `revert-buffer-function' is non-nil, it is called to
1801do the work.
1802
1803The default revert function runs the hook `before-revert-hook' at the
1804beginning and `after-revert-hook' at the end."
1805  ;; I admit it's odd to reverse the sense of the prefix argument, but
1806  ;; there is a lot of code out there which assumes that the first
1807  ;; argument should be t to avoid consulting the auto-save file, and
1808  ;; there's no straightforward way to encourage authors to notice a
1809  ;; reversal of the argument sense.  So I'm just changing the user
1810  ;; interface, but leaving the programmatic interface the same.
1811  (interactive (list (not prefix-arg)))
1812  (if revert-buffer-function
1813      (funcall revert-buffer-function ignore-auto noconfirm)
1814    (let* ((opoint (point))
1815	   (auto-save-p (and (not ignore-auto)
1816			     (recent-auto-save-p)
1817			     buffer-auto-save-file-name
1818			     (file-readable-p buffer-auto-save-file-name)
1819			     (y-or-n-p
1820   "Buffer has been auto-saved recently.  Revert from auto-save file? ")))
1821	   (file-name (if auto-save-p
1822			  buffer-auto-save-file-name
1823			buffer-file-name)))
1824      (cond ((null file-name)
1825	     (error "Buffer does not seem to be associated with any file"))
1826	    ((or noconfirm
1827		 (yes-or-no-p (format "Revert buffer from file %s? "
1828				      file-name)))
1829	     (run-hooks 'before-revert-hook)
1830	     ;; If file was backed up but has changed since,
1831	     ;; we shd make another backup.
1832	     (and (not auto-save-p)
1833		  (not (verify-visited-file-modtime (current-buffer)))
1834		  (setq buffer-backed-up nil))
1835	     ;; Get rid of all undo records for this buffer.
1836	     (or (eq buffer-undo-list t)
1837		 (setq buffer-undo-list nil))
1838	     (let ((buffer-read-only nil)
1839		   ;; Don't make undo records for the reversion.
1840		   (buffer-undo-list t))
1841	       (if revert-buffer-insert-file-contents-function
1842		   (funcall revert-buffer-insert-file-contents-function
1843			    file-name auto-save-p)
1844		 (if (not (file-exists-p file-name))
1845		     (error "File %s no longer exists!" file-name))
1846		 ;; Bind buffer-file-name to nil
1847		 ;; so that we don't try to lock the file.
1848		 (let ((buffer-file-name nil))
1849		   (or auto-save-p
1850		       (unlock-buffer)))
1851		 (widen)
1852		 (insert-file-contents file-name (not auto-save-p)
1853				       nil nil t)))
1854	     (goto-char (min opoint (point-max)))
1855	     (after-find-file nil nil t)
1856	     (run-hooks 'after-revert-hook)
1857	     t)))))
1858
1859(defun recover-file (file)
1860  "Visit file FILE, but get contents from its last auto-save file."
1861  (interactive
1862   (let ((prompt-file buffer-file-name)
1863	 (file-name nil)
1864	 (file-dir nil))
1865     (and prompt-file
1866	  (setq file-name (file-name-nondirectory prompt-file)
1867		file-dir (file-name-directory prompt-file)))
1868     (list (read-file-name "Recover file: "
1869			       file-dir nil nil file-name))))
1870  (setq file (expand-file-name file))
1871  (if (auto-save-file-name-p (file-name-nondirectory file))
1872      (error "%s is an auto-save file" file))
1873  (let ((file-name (let ((buffer-file-name file))
1874		     (make-auto-save-file-name))))
1875    (cond ((not (file-newer-than-file-p file-name file))
1876	   (error "Auto-save file %s not current" file-name))
1877	  ((save-window-excursion
1878	     (if (not (eq system-type 'vax-vms))
1879		 (with-output-to-temp-buffer "*Directory*"
1880		   (buffer-disable-undo standard-output)
1881		   (call-process "ls" nil standard-output nil
1882				 (if (file-symlink-p file) "-lL" "-l")
1883				 file file-name)))
1884	     (yes-or-no-p (format "Recover auto save file %s? " file-name)))
1885	   (switch-to-buffer (find-file-noselect file t))
1886	   (let ((buffer-read-only nil))
1887	     (erase-buffer)
1888	     (insert-file-contents file-name nil))
1889	   (after-find-file nil nil t))
1890	  (t (error "Recover-file cancelled.")))))
1891
1892(defun kill-some-buffers ()
1893  "For each buffer, ask whether to kill it."
1894  (interactive)
1895  (let ((list (buffer-list)))
1896    (while list
1897      (let* ((buffer (car list))
1898	     (name (buffer-name buffer)))
1899	(and (not (string-equal name ""))
1900	     (/= (aref name 0) ? )
1901	     (yes-or-no-p
1902	      (format "Buffer %s %s.  Kill? "
1903		      name
1904		      (if (buffer-modified-p buffer)
1905			  "HAS BEEN EDITED" "is unmodified")))
1906	     (kill-buffer buffer)))
1907      (setq list (cdr list)))))
1908
1909(defun auto-save-mode (arg)
1910  "Toggle auto-saving of contents of current buffer.
1911With prefix argument ARG, turn auto-saving on if positive, else off."
1912  (interactive "P")
1913  (setq buffer-auto-save-file-name
1914        (and (if (null arg)
1915		 (not buffer-auto-save-file-name)
1916	       (or (eq arg t) (listp arg) (and (integerp arg) (> arg 0))))
1917	     (if (and buffer-file-name auto-save-visited-file-name
1918		      (not buffer-read-only))
1919		 buffer-file-name
1920	       (make-auto-save-file-name))))
1921  ;; If -1 was stored here, to temporarily turn off saving,
1922  ;; turn it back on.
1923  (and (< buffer-saved-size 0)
1924       (setq buffer-saved-size 0))
1925  (if (interactive-p)
1926      (message "Auto-save %s (in this buffer)"
1927	       (if buffer-auto-save-file-name "on" "off")))
1928  buffer-auto-save-file-name)
1929
1930(defun rename-auto-save-file ()
1931  "Adjust current buffer's auto save file name for current conditions.
1932Also rename any existing auto save file, if it was made in this session."
1933  (let ((osave buffer-auto-save-file-name))
1934    (setq buffer-auto-save-file-name
1935	  (make-auto-save-file-name))
1936    (if (and osave buffer-auto-save-file-name
1937	     (not (string= buffer-auto-save-file-name buffer-file-name))
1938	     (not (string= buffer-auto-save-file-name osave))
1939	     (file-exists-p osave)
1940	     (recent-auto-save-p))
1941	(rename-file osave buffer-auto-save-file-name t))))
1942
1943(defun make-auto-save-file-name ()
1944  "Return file name to use for auto-saves of current buffer.
1945Does not consider `auto-save-visited-file-name' as that variable is checked
1946before calling this function.  You can redefine this for customization.
1947See also `auto-save-file-name-p'."
1948  (if buffer-file-name
1949      (concat (file-name-directory buffer-file-name)
1950	      "#"
1951	      (file-name-nondirectory buffer-file-name)
1952	      "#")
1953    ;; For non-file bfr, use bfr name and Emacs pid.
1954    (expand-file-name (format "#%s#%s#" (buffer-name) (make-temp-name "")))))
1955
1956(defun auto-save-file-name-p (filename)
1957  "Return non-nil if FILENAME can be yielded by `make-auto-save-file-name'.
1958FILENAME should lack slashes.  You can redefine this for customization."
1959  (string-match "^#.*#$" filename))
1960
1961(defconst list-directory-brief-switches
1962  (if (eq system-type 'vax-vms) "" "-CF")
1963  "*Switches for list-directory to pass to `ls' for brief listing,")
1964
1965(defconst list-directory-verbose-switches
1966  (if (eq system-type 'vax-vms)
1967      "/PROTECTION/SIZE/DATE/OWNER/WIDTH=(OWNER:10)"
1968    "-l")
1969  "*Switches for list-directory to pass to `ls' for verbose listing,")
1970
1971(defun list-directory (dirname &optional verbose)
1972  "Display a list of files in or matching DIRNAME, a la `ls'.
1973DIRNAME is globbed by the shell if necessary.
1974Prefix arg (second arg if noninteractive) means supply -l switch to `ls'.
1975Actions controlled by variables `list-directory-brief-switches'
1976and `list-directory-verbose-switches'."
1977  (interactive (let ((pfx current-prefix-arg))
1978		 (list (read-file-name (if pfx "List directory (verbose): "
1979					 "List directory (brief): ")
1980				       nil default-directory nil)
1981		       pfx)))
1982  (let ((switches (if verbose list-directory-verbose-switches
1983		    list-directory-brief-switches)))
1984    (or dirname (setq dirname default-directory))
1985    (setq dirname (expand-file-name dirname))
1986    (with-output-to-temp-buffer "*Directory*"
1987      (buffer-disable-undo standard-output)
1988      (princ "Directory ")
1989      (princ dirname)
1990      (terpri)
1991      (save-excursion
1992	(set-buffer "*Directory*")
1993	(let ((wildcard (not (file-directory-p dirname))))
1994	  (insert-directory dirname switches wildcard (not wildcard)))))))
1995
1996(defvar insert-directory-program "ls"
1997  "Absolute or relative name of the `ls' program used by `insert-directory'.")
1998
1999;; insert-directory
2000;; - must insert _exactly_one_line_ describing FILE if WILDCARD and
2001;;   FULL-DIRECTORY-P is nil.
2002;;   The single line of output must display FILE's name as it was
2003;;   given, namely, an absolute path name.
2004;; - must insert exactly one line for each file if WILDCARD or
2005;;   FULL-DIRECTORY-P is t, plus one optional "total" line
2006;;   before the file lines, plus optional text after the file lines.
2007;;   Lines are delimited by "\n", so filenames containing "\n" are not
2008;;   allowed.
2009;;   File lines should display the basename.
2010;; - must be consistent with
2011;;   - functions dired-move-to-filename, (these two define what a file line is)
2012;;   		 dired-move-to-end-of-filename,
2013;;		 dired-between-files, (shortcut for (not (dired-move-to-filename)))
2014;;   		 dired-insert-headerline
2015;;   		 dired-after-subdir-garbage (defines what a "total" line is)
2016;;   - variable dired-subdir-regexp
2017(defun insert-directory (file switches &optional wildcard full-directory-p)
2018  "Insert directory listing for FILE, formatted according to SWITCHES.
2019Leaves point after the inserted text.
2020Optional third arg WILDCARD means treat FILE as shell wildcard.
2021Optional fourth arg FULL-DIRECTORY-P means file is a directory and
2022switches do not contain `d', so that a full listing is expected.
2023
2024This works by running a directory listing program
2025whose name is in the variable `insert-directory-program'.
2026If WILDCARD, it also runs the shell specified by `shell-file-name'."
2027  ;; We need the directory in order to find the right handler.
2028  (let ((handler (find-file-name-handler (expand-file-name file)
2029					 'insert-directory)))
2030    (if handler
2031	(funcall handler 'insert-directory file switches
2032		 wildcard full-directory-p)
2033      (if (eq system-type 'vax-vms)
2034	  (vms-read-directory file switches (current-buffer))
2035	(if wildcard
2036	    ;; Run ls in the directory of the file pattern we asked for.
2037	    (let ((default-directory
2038		    (if (file-name-absolute-p file)
2039			(file-name-directory file)
2040		      (file-name-directory (expand-file-name file))))
2041		  (pattern (file-name-nondirectory file))
2042		  (beg 0))
2043	      ;; Quote some characters that have special meanings in shells;
2044	      ;; but don't quote the wildcards--we want them to be special.
2045	      ;; We also currently don't quote the quoting characters
2046	      ;; in case people want to use them explicitly to quote
2047	      ;; wildcard characters.
2048	      (while (string-match "[ \t\n;<>&|{}()#$]" pattern beg)
2049		(setq pattern
2050		      (concat (substring pattern 0 (match-beginning 0))
2051			      "\\"
2052			      (substring pattern (match-beginning 0)))
2053		      beg (1+ (match-end 0))))
2054	      (call-process shell-file-name nil t nil
2055			    "-c" (concat insert-directory-program
2056					 " -d " switches " "
2057					 pattern)))
2058	  ;; SunOS 4.1.3, SVr4 and others need the "." to list the
2059	  ;; directory if FILE is a symbolic link.
2060	  (call-process insert-directory-program nil t nil switches
2061			(if full-directory-p
2062			    (concat (file-name-as-directory file) ".")
2063			  file)))))))
2064
2065(defvar kill-emacs-query-functions nil
2066  "Functions to call with no arguments to query about killing Emacs.
2067If any of these functions returns nil, killing Emacs is cancelled.")
2068
2069(defun save-buffers-kill-emacs (&optional arg)
2070  "Offer to save each buffer, then kill this Emacs process.
2071With prefix arg, silently save all file-visiting buffers, then kill."
2072  (interactive "P")
2073  (save-some-buffers arg t)
2074  (and (or (not (memq t (mapcar (function
2075				  (lambda (buf) (and (buffer-file-name buf)
2076						     (buffer-modified-p buf))))
2077				(buffer-list))))
2078	   (yes-or-no-p "Modified buffers exist; exit anyway? "))
2079       (or (not (fboundp 'process-list))
2080	   ;; process-list is not defined on VMS.
2081	   (let ((processes (process-list))
2082		 active)
2083	     (while processes
2084	       (and (memq (process-status (car processes)) '(run stop open))
2085		    (let ((val (process-kill-without-query (car processes))))
2086		      (process-kill-without-query (car processes) val)
2087		      val)
2088		    (setq active t))
2089	       (setq processes (cdr processes)))
2090	     (or (not active)
2091		 (yes-or-no-p "Active processes exist; kill them and exit anyway? "))))
2092       ;; Query the user for other things, perhaps.
2093       (let ((functions kill-emacs-query-functions)
2094	     (yes t))
2095	 (while (and functions yes)
2096	   (setq yes (and yes (funcall (car functions))))
2097	   (setq functions (cdr functions)))
2098	 yes)
2099       (kill-emacs)))
2100
2101(define-key ctl-x-map "\C-f" 'find-file)
2102(define-key ctl-x-map "\C-q" 'toggle-read-only)
2103(define-key ctl-x-map "\C-r" 'find-file-read-only)
2104(define-key ctl-x-map "\C-v" 'find-alternate-file)
2105(define-key ctl-x-map "\C-s" 'save-buffer)
2106(define-key ctl-x-map "s" 'save-some-buffers)
2107(define-key ctl-x-map "\C-w" 'write-file)
2108(define-key ctl-x-map "i" 'insert-file)
2109(define-key esc-map "~" 'not-modified)
2110(define-key ctl-x-map "\C-d" 'list-directory)
2111(define-key ctl-x-map "\C-c" 'save-buffers-kill-emacs)
2112
2113(define-key ctl-x-4-map "f" 'find-file-other-window)
2114(define-key ctl-x-4-map "r" 'find-file-read-only-other-window)
2115(define-key ctl-x-4-map "\C-f" 'find-file-other-window)
2116(define-key ctl-x-4-map "b" 'switch-to-buffer-other-window)
2117(define-key ctl-x-4-map "\C-o" 'display-buffer)
2118
2119(define-key ctl-x-5-map "b" 'switch-to-buffer-other-frame)
2120(define-key ctl-x-5-map "f" 'find-file-other-frame)
2121(define-key ctl-x-5-map "\C-f" 'find-file-other-frame)
2122(define-key ctl-x-5-map "r" 'find-file-read-only-other-frame)
2123
2124;;; files.el ends here
2125