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-regexp-alist
39 ;; -u format: @@ -OLDSTART,OLDEND +NEWSTART,NEWEND @@
40 ("^@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@$" 1 2)
42 ;; -c format: *** OLDSTART,OLDEND ****
43 ("^\\*\\*\\* \\([0-9]+\\),[0-9]+ \\*\\*\\*\\*$" 1 nil)
44 ;; --- NEWSTART,NEWEND ----
45 ("^--- \\([0-9]+\\),[0-9]+ ----$" nil 1)
47 ;; plain diff format: OLDSTART[,OLDEND]{a,d,c}NEWSTART[,NEWEND]
48 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)\\(,[0-9]+\\)?$" 1 3)
50 ;; -e (ed) format: OLDSTART[,OLDEND]{a,d,c}
51 ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]$" 1)
53 ;; -f format: {a,d,c}OLDSTART[ OLDEND]
54 ;; -n format: {a,d,c}OLDSTART LINES-CHANGED
55 ("^[adc]\\([0-9]+\\)\\( [0-9]+\\)?$" 1)
57 "Alist (REGEXP OLD-IDX NEW-IDX) of regular expressions to match difference
58 sections in \\[diff] output. If REGEXP matches, the OLD-IDX'th
59 subexpression gives the line number in the old file, and NEW-IDX'th
60 subexpression gives the line number in the new file. If OLD-IDX or NEW-IDX
61 is nil, REGEXP matches only half a section.")
63 (defvar diff-old-file nil
64 "This is the old file name in the comparison in this buffer.")
65 (defvar diff-new-file nil
66 "This is the new file name in the comparison in this buffer.")
67 (defvar diff-old-temp-file nil
68 "This is the name of a temp file to be deleted after diff finishes.")
69 (defvar diff-new-temp-file nil
70 "This is the name of a temp file to be deleted after diff finishes.")
72 ;; See compilation-parse-errors-function (compile.el).
73 (defun diff-parse-differences (limit-search find-at-least)
74 (setq compilation-error-list nil)
75 (message "Parsing differences...")
77 ;; Don't reparse diffs already seen at last parse.
78 (if compilation-parsing-end (goto-char compilation-parsing-end))
80 ;; Construct in REGEXP a regexp composed of all those in dired-regexp-alist.
81 (let ((regexp (mapconcat (lambda (elt)
82 (concat "\\(" (car elt) "\\)"))
85 ;; (GROUP-IDX OLD-IDX NEW-IDX)
86 (groups (let ((subexpr 1))
94 (setq subexpr (+ subexpr 1
95 (count-regexp-groupings
100 (function (lambda (file subexpr)
101 (setq compilation-error-list
103 (cons (save-excursion
104 ;; Report location of message
105 ;; at beginning of line.
107 (match-beginning subexpr))
110 ;; Report location of corresponding text.
111 (let ((line (string-to-int
113 (match-beginning subexpr)
114 (match-end subexpr)))))
117 (set-buffer (find-file-noselect file)))
121 compilation-error-list)))))
127 (while (and (not found-desired)
128 ;; We don't just pass LIMIT-SEARCH to re-search-forward
129 ;; because we want to find matches containing LIMIT-SEARCH
130 ;; but which extend past it.
131 (re-search-forward regexp nil t))
133 ;; Find which individual regexp matched.
135 (while (and g (null (match-beginning (car (car g)))))
139 (if (nth 1 g) ;OLD-IDX
140 (funcall new-error diff-old-file (nth 1 g)))
141 (if (nth 2 g) ;NEW-IDX
142 (funcall new-error diff-new-file (nth 2 g)))
144 (setq num-loci-found (1+ num-loci-found))
145 (if (or (and find-at-least
146 (>= num-loci-found find-at-least))
147 (and limit-search (>= (point) limit-search)))
148 ;; We have found as many new loci as the user wants,
149 ;; or the user wanted a specific diff, and we're past it.
150 (setq found-desired t)))
152 (setq compilation-parsing-end (point))
153 ;; Set to point-max, not point, so we don't perpetually
154 ;; parse the last bit of text when it isn't a diff header.
155 (setq compilation-parsing-end (point-max)))
156 (message "Parsing differences...done"))
157 (setq compilation-error-list (nreverse compilation-error-list)))
160 (defun diff (old new &optional switches)
161 "Find and display the differences between OLD and NEW files.
162 Interactively the current buffer's file name is the default for NEW
163 and a backup file for NEW is the default for OLD.
164 With prefix arg, prompt for diff switches."
170 (setq newf (buffer-file-name)
171 newf (if (and newf (file-exists-p newf))
173 (concat "Diff new file: ("
174 (file-name-nondirectory newf) ") ")
176 (read-file-name "Diff new file: " nil nil t)))
177 (setq oldf (file-newest-backup newf)
178 oldf (if (and oldf (file-exists-p oldf))
180 (concat "Diff original file: ("
181 (file-name-nondirectory oldf) ") ")
182 (file-name-directory oldf) oldf t)
183 (read-file-name "Diff original file: "
184 (file-name-directory newf) nil t))))))
185 (if current-prefix-arg
186 (list (read-string "Diff switches: "
187 (if (stringp diff-switches)
189 (mapconcat 'identity diff-switches " "))))
191 (setq new (expand-file-name new)
192 old (expand-file-name old))
193 (let ((old-alt (file-local-copy old))
194 (new-alt (file-local-copy new))
200 ;; Use explicitly specified switches
203 switches (list switches))
204 ;; If not specified, use default.
205 (if (consp diff-switches)
207 (list diff-switches)))
208 (if (or old-alt new-alt)
209 (list "-L" old "-L" new))
211 (shell-quote-argument (or old-alt old)))
213 (shell-quote-argument (or new-alt new))))
216 (compile-internal command
217 "No more differences" "Diff"
218 'diff-parse-differences))
220 (set (make-local-variable 'diff-old-file) old)
221 (set (make-local-variable 'diff-new-file) new)
222 (set (make-local-variable 'diff-old-temp-file) old-alt)
223 (set (make-local-variable 'diff-new-temp-file) new-alt)
224 (set (make-local-variable 'compilation-finish-function)
225 (function (lambda (buff msg)
226 (if diff-old-temp-file
227 (delete-file diff-old-temp-file))
228 (if diff-new-temp-file
229 (delete-file diff-new-temp-file)))))
233 (defun diff-backup (file &optional switches)
234 "Diff this file with its backup file or vice versa.
235 Uses the latest backup, if there are several numerical backups.
236 If this file is a backup, diff it with its original.
237 The backup file is the first file given to `diff'."
238 (interactive (list (read-file-name "Diff (file with backup): ")
239 (if current-prefix-arg
240 (read-string "Diff switches: "
241 (if (stringp diff-switches)
247 (if (backup-file-name-p file)
249 ori (file-name-sans-versions file))
250 (setq bak (or (diff-latest-backup-file file)
251 (error "No backup found for %s" file))
253 (diff bak ori switches)))
255 (defun diff-latest-backup-file (fn) ; actually belongs into files.el
256 "Return the latest existing backup of FILE, or nil."
257 (let ((handler (find-file-name-handler fn)))
259 (funcall handler 'diff-latest-backup-file fn)
260 ;; First try simple backup, then the highest numbered of the
262 ;; Ignore the value of version-control because we look for existing
263 ;; backups, which maybe were made earlier or by another user with
264 ;; a different value of version-control.
265 (setq fn (file-chase-links (expand-file-name fn)))
267 (let ((bak (make-backup-file-name fn)))
268 (if (file-exists-p bak) bak))
269 (let* ((dir (file-name-directory fn))
270 (base-versions (concat (file-name-nondirectory fn) ".~"))
271 (bv-length (length base-versions)))
274 (file-name-all-completions base-versions dir)
275 ;; bv-length is a fluid var for backup-extract-version:
278 (> (backup-extract-version fn1)
279 (backup-extract-version fn2))))))))))))
283 ;;; diff.el ends here