1 ;;; diff.el --- Run `diff' in compilation-mode.
3 ;; Copyright (C) 1992, 1994, 1996 Free Software Foundation, Inc.
5 ;; Keywords: unix, tools
7 ;; This file is part of GNU Emacs.
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)
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.
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 the
21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 ;; Boston, MA 02111-1307, USA.
26 ;; This package helps you explore differences between files, using the
27 ;; UNIX command diff(1). The commands are `diff' and `diff-backup'.
28 ;; You can specify options with `diff-switches'.
34 ;;; This is duplicated in vc.el.
35 (defvar diff-switches "-c"
36 "*A string or list of strings specifying switches to be be passed to diff.")
38 (defvar diff-command "diff"
39 "*The command to use to run diff.")
41 (defvar diff-regexp-alist
43 ;; -u format: @@ -OLDSTART,OLDEND +NEWSTART,NEWEND @@
44 ("^@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@$" 1 2)
46 ;; -c format: *** OLDSTART,OLDEND ****
47 ("^\\*\\*\\* \\([0-9]+\\),[0-9]+ \\*\\*\\*\\*$" 1 nil)
48 ;; --- NEWSTART,NEWEND ----
49 ("^--- \\([0-9]+\\),[0-9]+ ----$" nil 1)
51 ;; plain diff format: OLDSTART[,OLDEND]{a,d,c}NEWSTART[,NEWEND]
52 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)\\(,[0-9]+\\)?$" 1 3)
54 ;; -e (ed) format: OLDSTART[,OLDEND]{a,d,c}
55 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]$" 1)
57 ;; -f format: {a,d,c}OLDSTART[ OLDEND]
58 ;; -n format: {a,d,c}OLDSTART LINES-CHANGED
59 ("^[adc]\\([0-9]+\\)\\( [0-9]+\\)?$" 1)
61 "Alist (REGEXP OLD-IDX NEW-IDX) of regular expressions to match difference
62 sections in \\[diff] output. If REGEXP matches, the OLD-IDX'th
63 subexpression gives the line number in the old file, and NEW-IDX'th
64 subexpression gives the line number in the new file. If OLD-IDX or NEW-IDX
65 is nil, REGEXP matches only half a section.")
67 (defvar diff-old-file nil
68 "This is the old file name in the comparison in this buffer.")
69 (defvar diff-new-file nil
70 "This is the new file name in the comparison in this buffer.")
71 (defvar diff-old-temp-file nil
72 "This is the name of a temp file to be deleted after diff finishes.")
73 (defvar diff-new-temp-file nil
74 "This is the name of a temp file to be deleted after diff finishes.")
76 ;; See compilation-parse-errors-function (compile.el).
77 (defun diff-parse-differences (limit-search find-at-least)
78 (setq compilation-error-list nil)
79 (message "Parsing differences...")
81 ;; Don't reparse diffs already seen at last parse.
82 (if compilation-parsing-end (goto-char compilation-parsing-end))
84 ;; Construct in REGEXP a regexp composed of all those in dired-regexp-alist.
85 (let ((regexp (mapconcat (lambda (elt)
86 (concat "\\(" (car elt) "\\)"))
89 ;; (GROUP-IDX OLD-IDX NEW-IDX)
90 (groups (let ((subexpr 1))
98 (setq subexpr (+ subexpr 1
99 (count-regexp-groupings
104 (function (lambda (file subexpr)
105 (setq compilation-error-list
107 (cons (save-excursion
108 ;; Report location of message
109 ;; at beginning of line.
111 (match-beginning subexpr))
114 ;; Report location of corresponding text.
115 (let ((line (string-to-int
117 (match-beginning subexpr)
118 (match-end subexpr)))))
121 (set-buffer (find-file-noselect file)))
125 compilation-error-list)))))
131 (while (and (not found-desired)
132 ;; We don't just pass LIMIT-SEARCH to re-search-forward
133 ;; because we want to find matches containing LIMIT-SEARCH
134 ;; but which extend past it.
135 (re-search-forward regexp nil t))
137 ;; Find which individual regexp matched.
139 (while (and g (null (match-beginning (car (car g)))))
143 (if (nth 1 g) ;OLD-IDX
144 (funcall new-error diff-old-file (nth 1 g)))
145 (if (nth 2 g) ;NEW-IDX
146 (funcall new-error diff-new-file (nth 2 g)))
148 (setq num-loci-found (1+ num-loci-found))
149 (if (or (and find-at-least
150 (>= num-loci-found find-at-least))
151 (and limit-search (>= (point) limit-search)))
152 ;; We have found as many new loci as the user wants,
153 ;; or the user wanted a specific diff, and we're past it.
154 (setq found-desired t)))
156 (setq compilation-parsing-end (point))
157 ;; Set to point-max, not point, so we don't perpetually
158 ;; parse the last bit of text when it isn't a diff header.
159 (setq compilation-parsing-end (point-max)))
160 (message "Parsing differences...done"))
161 (setq compilation-error-list (nreverse compilation-error-list)))
163 (defun diff-process-setup ()
164 "Set up \`compilation-exit-message-function' for \`diff'."
165 ;; Avoid frightening people with "abnormally terminated"
166 ;; if diff finds differences.
167 (set (make-local-variable 'compilation-exit-message-function)
168 (lambda (status code msg)
169 (cond ((not (eq status 'exit))
172 '("finished (no differences)\n" . "no differences"))
174 '("finished\n" . "differences found"))
179 (defun diff (old new &optional switches)
180 "Find and display the differences between OLD and NEW files.
181 Interactively the current buffer's file name is the default for NEW
182 and a backup file for NEW is the default for OLD.
183 With prefix arg, prompt for diff switches."
189 (setq newf (buffer-file-name)
190 newf (if (and newf (file-exists-p newf))
192 (concat "Diff new file: ("
193 (file-name-nondirectory newf) ") ")
195 (read-file-name "Diff new file: " nil nil t)))
196 (setq oldf (file-newest-backup newf)
197 oldf (if (and oldf (file-exists-p oldf))
199 (concat "Diff original file: ("
200 (file-name-nondirectory oldf) ") ")
201 (file-name-directory oldf) oldf t)
202 (read-file-name "Diff original file: "
203 (file-name-directory newf) nil t))))))
204 (if current-prefix-arg
205 (list (read-string "Diff switches: "
206 (if (stringp diff-switches)
208 (mapconcat 'identity diff-switches " "))))
210 (setq new (expand-file-name new)
211 old (expand-file-name old))
212 (let ((old-alt (file-local-copy old))
213 (new-alt (file-local-copy new))
216 (let ((compilation-process-setup-function 'diff-process-setup)
219 (append (list diff-command)
220 ;; Use explicitly specified switches
223 switches (list switches))
224 ;; If not specified, use default.
225 (if (consp diff-switches)
227 (list diff-switches)))
228 (if (or old-alt new-alt)
229 (list "-L" old "-L" new))
231 (shell-quote-argument (or old-alt old)))
233 (shell-quote-argument (or new-alt new))))
236 (compile-internal command
237 "No more differences" "Diff"
238 'diff-parse-differences))
240 (set (make-local-variable 'diff-old-file) old)
241 (set (make-local-variable 'diff-new-file) new)
242 (set (make-local-variable 'diff-old-temp-file) old-alt)
243 (set (make-local-variable 'diff-new-temp-file) new-alt)
244 (set (make-local-variable 'compilation-finish-function)
245 (function (lambda (buff msg)
246 (if diff-old-temp-file
247 (delete-file diff-old-temp-file))
248 (if diff-new-temp-file
249 (delete-file diff-new-temp-file)))))
250 ;; When async processes aren't available, the compilation finish
251 ;; function doesn't get chance to run. Invoke it by hand.
252 (or (fboundp 'start-process)
253 (funcall compilation-finish-function nil nil))
257 (defun diff-backup (file &optional switches)
258 "Diff this file with its backup file or vice versa.
259 Uses the latest backup, if there are several numerical backups.
260 If this file is a backup, diff it with its original.
261 The backup file is the first file given to `diff'."
262 (interactive (list (read-file-name "Diff (file with backup): ")
263 (if current-prefix-arg
264 (read-string "Diff switches: "
265 (if (stringp diff-switches)
271 (if (backup-file-name-p file)
273 ori (file-name-sans-versions file))
274 (setq bak (or (diff-latest-backup-file file)
275 (error "No backup found for %s" file))
277 (diff bak ori switches)))
279 (defun diff-latest-backup-file (fn) ; actually belongs into files.el
280 "Return the latest existing backup of FILE, or nil."
281 (let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
283 (funcall handler 'diff-latest-backup-file fn)
284 ;; First try simple backup, then the highest numbered of the
286 ;; Ignore the value of version-control because we look for existing
287 ;; backups, which maybe were made earlier or by another user with
288 ;; a different value of version-control.
289 (setq fn (file-chase-links (expand-file-name fn)))
291 (let ((bak (make-backup-file-name fn)))
292 (if (file-exists-p bak) bak))
293 ;; We use BACKUPNAME to cope with backups stored in a different dir.
294 (let* ((backupname (car (find-backup-file-name fn)))
295 (dir (file-name-directory backupname))
296 (base-versions (concat (file-name-sans-versions
297 (file-name-nondirectory backupname))
299 ;; This is a fluid var for backup-extract-version.
300 (backup-extract-version-start (length base-versions)))
303 (file-name-all-completions base-versions dir)
306 (> (backup-extract-version fn1)
307 (backup-extract-version fn2))))))))))))
311 ;;; diff.el ends here