1 ;;; diff.el --- Run `diff' in compilation-mode.
3 ;; Copyright (C) 1992 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 ;; First try simple backup, then the highest numbered of the
259 ;; Ignore the value of version-control because we look for existing
260 ;; backups, which maybe were made earlier or by another user with
261 ;; a different value of version-control.
262 (setq fn
(file-chase-links (expand-file-name fn
)))
264 (let ((bak (make-backup-file-name fn
)))
265 (if (file-exists-p bak
) bak
))
266 (let* ((dir (file-name-directory fn
))
267 (base-versions (concat (file-name-nondirectory fn
) ".~"))
268 (bv-length (length base-versions
)))
271 (file-name-all-completions base-versions dir
)
272 ;; bv-length is a fluid var for backup-extract-version:
275 (> (backup-extract-version fn1
)
276 (backup-extract-version fn2
))))))))))
280 ;;; diff.el ends here