1 ;;; diff.el --- Run `diff' in compilation-mode.
3 ;; Copyright (C) 1992, 1994 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
21 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
25 ;; This package helps you explore differences between files, using the
26 ;; UNIX command diff(1). The commands are `diff' and `diff-backup'.
27 ;; You can specify options with `diff-switches'.
33 ;;; This is duplicated in vc.el.
34 (defvar diff-switches "-c"
35 "*A string or list of strings specifying switches to be be passed to diff.")
37 (defvar diff-command "diff"
38 "*The command to use to run diff.")
40 (defvar diff-regexp-alist
42 ;; -u format: @@ -OLDSTART,OLDEND +NEWSTART,NEWEND @@
43 ("^@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@$" 1 2)
45 ;; -c format: *** OLDSTART,OLDEND ****
46 ("^\\*\\*\\* \\([0-9]+\\),[0-9]+ \\*\\*\\*\\*$" 1 nil)
47 ;; --- NEWSTART,NEWEND ----
48 ("^--- \\([0-9]+\\),[0-9]+ ----$" nil 1)
50 ;; plain diff format: OLDSTART[,OLDEND]{a,d,c}NEWSTART[,NEWEND]
51 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)\\(,[0-9]+\\)?$" 1 3)
53 ;; -e (ed) format: OLDSTART[,OLDEND]{a,d,c}
54 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]$" 1)
56 ;; -f format: {a,d,c}OLDSTART[ OLDEND]
57 ;; -n format: {a,d,c}OLDSTART LINES-CHANGED
58 ("^[adc]\\([0-9]+\\)\\( [0-9]+\\)?$" 1)
60 "Alist (REGEXP OLD-IDX NEW-IDX) of regular expressions to match difference
61 sections in \\[diff] output. If REGEXP matches, the OLD-IDX'th
62 subexpression gives the line number in the old file, and NEW-IDX'th
63 subexpression gives the line number in the new file. If OLD-IDX or NEW-IDX
64 is nil, REGEXP matches only half a section.")
66 (defvar diff-old-file nil
67 "This is the old file name in the comparison in this buffer.")
68 (defvar diff-new-file nil
69 "This is the new file name in the comparison in this buffer.")
70 (defvar diff-old-temp-file nil
71 "This is the name of a temp file to be deleted after diff finishes.")
72 (defvar diff-new-temp-file nil
73 "This is the name of a temp file to be deleted after diff finishes.")
75 ;; See compilation-parse-errors-function (compile.el).
76 (defun diff-parse-differences (limit-search find-at-least)
77 (setq compilation-error-list nil)
78 (message "Parsing differences...")
80 ;; Don't reparse diffs already seen at last parse.
81 (if compilation-parsing-end (goto-char compilation-parsing-end))
83 ;; Construct in REGEXP a regexp composed of all those in dired-regexp-alist.
84 (let ((regexp (mapconcat (lambda (elt)
85 (concat "\\(" (car elt) "\\)"))
88 ;; (GROUP-IDX OLD-IDX NEW-IDX)
89 (groups (let ((subexpr 1))
97 (setq subexpr (+ subexpr 1
98 (count-regexp-groupings
103 (function (lambda (file subexpr)
104 (setq compilation-error-list
106 (cons (save-excursion
107 ;; Report location of message
108 ;; at beginning of line.
110 (match-beginning subexpr))
113 ;; Report location of corresponding text.
114 (let ((line (string-to-int
116 (match-beginning subexpr)
117 (match-end subexpr)))))
120 (set-buffer (find-file-noselect file)))
124 compilation-error-list)))))
130 (while (and (not found-desired)
131 ;; We don't just pass LIMIT-SEARCH to re-search-forward
132 ;; because we want to find matches containing LIMIT-SEARCH
133 ;; but which extend past it.
134 (re-search-forward regexp nil t))
136 ;; Find which individual regexp matched.
138 (while (and g (null (match-beginning (car (car g)))))
142 (if (nth 1 g) ;OLD-IDX
143 (funcall new-error diff-old-file (nth 1 g)))
144 (if (nth 2 g) ;NEW-IDX
145 (funcall new-error diff-new-file (nth 2 g)))
147 (setq num-loci-found (1+ num-loci-found))
148 (if (or (and find-at-least
149 (>= num-loci-found find-at-least))
150 (and limit-search (>= (point) limit-search)))
151 ;; We have found as many new loci as the user wants,
152 ;; or the user wanted a specific diff, and we're past it.
153 (setq found-desired t)))
155 (setq compilation-parsing-end (point))
156 ;; Set to point-max, not point, so we don't perpetually
157 ;; parse the last bit of text when it isn't a diff header.
158 (setq compilation-parsing-end (point-max)))
159 (message "Parsing differences...done"))
160 (setq compilation-error-list (nreverse compilation-error-list)))
163 (defun diff (old new &optional switches)
164 "Find and display the differences between OLD and NEW files.
165 Interactively the current buffer's file name is the default for NEW
166 and a backup file for NEW is the default for OLD.
167 With prefix arg, prompt for diff switches."
173 (setq newf (buffer-file-name)
174 newf (if (and newf (file-exists-p newf))
176 (concat "Diff new file: ("
177 (file-name-nondirectory newf) ") ")
179 (read-file-name "Diff new file: " nil nil t)))
180 (setq oldf (file-newest-backup newf)
181 oldf (if (and oldf (file-exists-p oldf))
183 (concat "Diff original file: ("
184 (file-name-nondirectory oldf) ") ")
185 (file-name-directory oldf) oldf t)
186 (read-file-name "Diff original file: "
187 (file-name-directory newf) nil t))))))
188 (if current-prefix-arg
189 (list (read-string "Diff switches: "
190 (if (stringp diff-switches)
192 (mapconcat 'identity diff-switches " "))))
194 (setq new (expand-file-name new)
195 old (expand-file-name old))
196 (let ((old-alt (file-local-copy old))
197 (new-alt (file-local-copy new))
202 (append (list diff-command)
203 ;; Use explicitly specified switches
206 switches (list switches))
207 ;; If not specified, use default.
208 (if (consp diff-switches)
210 (list diff-switches)))
211 (if (or old-alt new-alt)
212 (list "-L" old "-L" new))
214 (shell-quote-argument (or old-alt old)))
216 (shell-quote-argument (or new-alt new))))
219 (compile-internal command
220 "No more differences" "Diff"
221 'diff-parse-differences))
223 (set (make-local-variable 'diff-old-file) old)
224 (set (make-local-variable 'diff-new-file) new)
225 (set (make-local-variable 'diff-old-temp-file) old-alt)
226 (set (make-local-variable 'diff-new-temp-file) new-alt)
227 (set (make-local-variable 'compilation-finish-function)
228 (function (lambda (buff msg)
229 (if diff-old-temp-file
230 (delete-file diff-old-temp-file))
231 (if diff-new-temp-file
232 (delete-file diff-new-temp-file)))))
236 (defun diff-backup (file &optional switches)
237 "Diff this file with its backup file or vice versa.
238 Uses the latest backup, if there are several numerical backups.
239 If this file is a backup, diff it with its original.
240 The backup file is the first file given to `diff'."
241 (interactive (list (read-file-name "Diff (file with backup): ")
242 (if current-prefix-arg
243 (read-string "Diff switches: "
244 (if (stringp diff-switches)
250 (if (backup-file-name-p file)
252 ori (file-name-sans-versions file))
253 (setq bak (or (diff-latest-backup-file file)
254 (error "No backup found for %s" file))
256 (diff bak ori switches)))
258 (defun diff-latest-backup-file (fn) ; actually belongs into files.el
259 "Return the latest existing backup of FILE, or nil."
260 (let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
262 (funcall handler 'diff-latest-backup-file fn)
263 ;; First try simple backup, then the highest numbered of the
265 ;; Ignore the value of version-control because we look for existing
266 ;; backups, which maybe were made earlier or by another user with
267 ;; a different value of version-control.
268 (setq fn (file-chase-links (expand-file-name fn)))
270 (let ((bak (make-backup-file-name fn)))
271 (if (file-exists-p bak) bak))
272 ;; We use BACKUPNAME to cope with backups stored in a different dir.
273 (let* ((backupname (car (find-backup-file-name fn)))
274 (dir (file-name-directory backupname))
275 (base-versions (concat (file-name-sans-versions
276 (file-name-nondirectory backupname))
278 (bv-length (length base-versions)))
281 (file-name-all-completions base-versions dir)
282 ;; bv-length is a fluid var for backup-extract-version:
285 (> (backup-extract-version fn1)
286 (backup-extract-version fn2))))))))))))
290 ;;; diff.el ends here