1 ;;; diff.el --- run `diff' in compilation-mode
3 ;; Copyright (C) 1992, 1994, 1996, 2001 Free Software Foundation, Inc.
6 ;; Keywords: unix, tools
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software; you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
27 ;; This package helps you explore differences between files, using the
28 ;; UNIX command diff(1). The commands are `diff' and `diff-backup'.
29 ;; You can specify options with `diff-switches'.
36 "Comparing files with `diff'."
40 (defcustom diff-switches "-c"
41 "*A string or list of strings specifying switches to be be passed to diff."
42 :type '(choice string (repeat string))
46 (defcustom diff-command "diff"
47 "*The command to use to run diff."
51 (defvar diff-regexp-alist
53 ;; -u format: @@ -OLDSTART,OLDEND +NEWSTART,NEWEND @@
54 ("^@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@$" 1 2)
56 ;; -c format: *** OLDSTART,OLDEND ****
57 ("^\\*\\*\\* \\([0-9]+\\),[0-9]+ \\*\\*\\*\\*$" 1 nil)
58 ;; --- NEWSTART,NEWEND ----
59 ("^--- \\([0-9]+\\),[0-9]+ ----$" nil 1)
61 ;; plain diff format: OLDSTART[,OLDEND]{a,d,c}NEWSTART[,NEWEND]
62 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)\\(,[0-9]+\\)?$" 1 3)
64 ;; -e (ed) format: OLDSTART[,OLDEND]{a,d,c}
65 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]$" 1)
67 ;; -f format: {a,d,c}OLDSTART[ OLDEND]
68 ;; -n format: {a,d,c}OLDSTART LINES-CHANGED
69 ("^[adc]\\([0-9]+\\)\\( [0-9]+\\)?$" 1)
71 "Alist (REGEXP OLD-IDX NEW-IDX) of regular expressions to match difference
72 sections in \\[diff] output. If REGEXP matches, the OLD-IDX'th
73 subexpression gives the line number in the old file, and NEW-IDX'th
74 subexpression gives the line number in the new file. If OLD-IDX or NEW-IDX
75 is nil, REGEXP matches only half a section.")
77 (defvar diff-old-file nil
78 "This is the old file name in the comparison in this buffer.")
79 (defvar diff-new-file nil
80 "This is the new file name in the comparison in this buffer.")
81 (defvar diff-old-temp-file nil
82 "This is the name of a temp file to be deleted after diff finishes.")
83 (defvar diff-new-temp-file nil
84 "This is the name of a temp file to be deleted after diff finishes.")
86 ;; See compilation-parse-errors-function (compile.el).
87 (defun diff-parse-differences (limit-search find-at-least)
88 (setq compilation-error-list nil)
89 (message "Parsing differences...")
91 ;; Don't reparse diffs already seen at last parse.
92 (if compilation-parsing-end (goto-char compilation-parsing-end))
94 ;; Construct in REGEXP a regexp composed of all those in dired-regexp-alist.
95 (let ((regexp (mapconcat (lambda (elt)
96 (concat "\\(" (car elt) "\\)"))
99 ;; (GROUP-IDX OLD-IDX NEW-IDX)
100 (groups (let ((subexpr 1))
101 (mapcar (lambda (elt)
108 (setq subexpr (+ subexpr 1
109 (count-regexp-groupings
114 (function (lambda (file subexpr)
115 (setq compilation-error-list
117 (cons (save-excursion
118 ;; Report location of message
119 ;; at beginning of line.
121 (match-beginning subexpr))
124 ;; Report location of corresponding text.
125 (let ((line (string-to-int
127 (match-beginning subexpr)
128 (match-end subexpr)))))
131 (set-buffer (find-file-noselect file)))
135 compilation-error-list)))))
141 (while (and (not found-desired)
142 ;; We don't just pass LIMIT-SEARCH to re-search-forward
143 ;; because we want to find matches containing LIMIT-SEARCH
144 ;; but which extend past it.
145 (re-search-forward regexp nil t))
147 ;; Find which individual regexp matched.
149 (while (and g (null (match-beginning (car (car g)))))
153 (if (nth 1 g) ;OLD-IDX
154 (funcall new-error diff-old-file (nth 1 g)))
155 (if (nth 2 g) ;NEW-IDX
156 (funcall new-error diff-new-file (nth 2 g)))
158 (setq num-loci-found (1+ num-loci-found))
159 (if (or (and find-at-least
160 (>= num-loci-found find-at-least))
161 (and limit-search (>= (point) limit-search)))
162 ;; We have found as many new loci as the user wants,
163 ;; or the user wanted a specific diff, and we're past it.
164 (setq found-desired t)))
165 (set-marker compilation-parsing-end
166 (if found-desired (point)
167 ;; Set to point-max, not point, so we don't perpetually
168 ;; parse the last bit of text when it isn't a diff header.
170 (message "Parsing differences...done"))
171 (setq compilation-error-list (nreverse compilation-error-list)))
173 (defun diff-process-setup ()
174 "Set up \`compilation-exit-message-function' for \`diff'."
175 ;; Avoid frightening people with "abnormally terminated"
176 ;; if diff finds differences.
177 (set (make-local-variable 'compilation-exit-message-function)
178 (lambda (status code msg)
179 (cond ((not (eq status 'exit))
182 '("finished (no differences)\n" . "no differences"))
184 '("finished\n" . "differences found"))
189 (defun diff (old new &optional switches)
190 "Find and display the differences between OLD and NEW files.
191 Interactively the current buffer's file name is the default for NEW
192 and a backup file for NEW is the default for OLD.
193 With prefix arg, prompt for diff switches."
199 (setq newf (buffer-file-name)
200 newf (if (and newf (file-exists-p newf))
202 (concat "Diff new file: (default "
203 (file-name-nondirectory newf) ") ")
205 (read-file-name "Diff new file: " nil nil t)))
206 (setq oldf (file-newest-backup newf)
207 oldf (if (and oldf (file-exists-p oldf))
209 (concat "Diff original file: (default "
210 (file-name-nondirectory oldf) ") ")
211 (file-name-directory oldf) oldf t)
212 (read-file-name "Diff original file: "
213 (file-name-directory newf) nil t))))))
214 (if current-prefix-arg
215 (list (read-string "Diff switches: "
216 (if (stringp diff-switches)
218 (mapconcat 'identity diff-switches " "))))
220 (setq new (expand-file-name new)
221 old (expand-file-name old))
222 (let ((old-alt (file-local-copy old))
223 (new-alt (file-local-copy new))
226 (let ((compilation-process-setup-function 'diff-process-setup)
229 (append (list diff-command)
230 ;; Use explicitly specified switches
233 switches (list switches))
234 ;; If not specified, use default.
235 (if (consp diff-switches)
237 (list diff-switches)))
238 (if (or old-alt new-alt)
239 (list "-L" old "-L" new))
241 (shell-quote-argument (or old-alt old)))
243 (shell-quote-argument (or new-alt new))))
246 (compile-internal command
247 "No more differences" "Diff"
248 'diff-parse-differences))
250 (set (make-local-variable 'diff-old-file) old)
251 (set (make-local-variable 'diff-new-file) new)
252 (set (make-local-variable 'diff-old-temp-file) old-alt)
253 (set (make-local-variable 'diff-new-temp-file) new-alt)
254 (set (make-local-variable 'compilation-finish-function)
255 (function (lambda (buff msg)
256 (if diff-old-temp-file
257 (delete-file diff-old-temp-file))
258 (if diff-new-temp-file
259 (delete-file diff-new-temp-file)))))
260 ;; When async processes aren't available, the compilation finish
261 ;; function doesn't get chance to run. Invoke it by hand.
262 (or (fboundp 'start-process)
263 (funcall compilation-finish-function nil nil))
267 (defun diff-backup (file &optional switches)
268 "Diff this file with its backup file or vice versa.
269 Uses the latest backup, if there are several numerical backups.
270 If this file is a backup, diff it with its original.
271 The backup file is the first file given to `diff'."
272 (interactive (list (read-file-name "Diff (file with backup): ")
273 (if current-prefix-arg
274 (read-string "Diff switches: "
275 (if (stringp diff-switches)
281 (if (backup-file-name-p file)
283 ori (file-name-sans-versions file))
284 (setq bak (or (diff-latest-backup-file file)
285 (error "No backup found for %s" file))
287 (diff bak ori switches)))
289 (defun diff-latest-backup-file (fn) ; actually belongs into files.el
290 "Return the latest existing backup of FILE, or nil."
291 (let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
293 (funcall handler 'diff-latest-backup-file fn)
294 ;; First try simple backup, then the highest numbered of the
296 ;; Ignore the value of version-control because we look for existing
297 ;; backups, which maybe were made earlier or by another user with
298 ;; a different value of version-control.
299 (setq fn (file-chase-links (expand-file-name fn)))
301 (let ((bak (make-backup-file-name fn)))
302 (if (file-exists-p bak) bak))
303 ;; We use BACKUPNAME to cope with backups stored in a different dir.
304 (let* ((backupname (car (find-backup-file-name fn)))
305 (dir (file-name-directory backupname))
306 (base-versions (concat (file-name-sans-versions
307 (file-name-nondirectory backupname))
309 ;; This is a fluid var for backup-extract-version.
310 (backup-extract-version-start (length base-versions)))
313 (file-name-all-completions base-versions dir)
316 (> (backup-extract-version fn1)
317 (backup-extract-version fn2))))))))))))
321 ;;; diff.el ends here