diff-mode.el 44.3 KB
Newer Older
Pavel Janík's avatar
Pavel Janík committed
1
;;; diff-mode.el --- a mode for viewing/editing context diffs
2

3
;; Copyright (C) 1998,1999,2000,01,02,03,2004  Free Software Foundation, Inc.
4 5

;; Author: Stefan Monnier <monnier@cs.yale.edu>
Pavel Janík's avatar
Pavel Janík committed
6
;; Keywords: convenience patch diff
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

27
;; Provides support for font-lock, outline, navigation
28 29 30
;; commands, editing and various conversions as well as jumping
;; to the corresponding source file.

31
;; Inspired by Pavel Machek's patch-mode.el (<pavel@@atrey.karlin.mff.cuni.cz>)
Pavel Janík's avatar
Pavel Janík committed
32
;; Some efforts were spent to have it somewhat compatible with XEmacs'
33 34 35 36
;; diff-mode as well as with compilation-minor-mode

;; Bugs:

37
;; - Reverse doesn't work with normal diffs.
38 39 40

;; Todo:

41
;; - Improve narrowed-view support.
42 43
;; - re-enable (conditionally) the `compile' support after improving it to use
;;   the same code as diff-goto-source.
44 45 46 47 48 49
;; - Support for # comments in context->unified.
;; - Allow diff.el to use diff-mode.
;;   This mostly means ability to jump from half-hunk to half-hunk
;;   in context (and normal) diffs and to jump to the corresponding
;;   (i.e. new or old) file.
;; - Handle `diff -b' output in context->unified.
50

51 52 53 54
;; Low priority:
;; - Spice up the minor-mode with font-lock support.
;; - Recognize pcl-cvs' special string for `cvs-execute-single'.

55 56 57 58 59 60
;;; Code:

(eval-when-compile (require 'cl))


(defgroup diff-mode ()
61
  "Major mode for viewing/editing diffs"
62
  :version "21.1"
63 64 65
  :group 'tools
  :group 'diff)

66 67 68 69 70
(defcustom diff-default-read-only t
  "If non-nil, `diff-mode' buffers default to being read-only."
  :type 'boolean
  :group 'diff-mode)

71
(defcustom diff-jump-to-old-file nil
72 73 74 75
  "*Non-nil means `diff-goto-source' jumps to the old file.
Else, it jumps to the new file."
  :type '(boolean))

76
(defcustom diff-update-on-the-fly t
77 78 79 80 81 82 83 84
  "*Non-nil means hunk headers are kept up-to-date on-the-fly.
When editing a diff file, the line numbers in the hunk headers
need to be kept consistent with the actual diff.  This can
either be done on the fly (but this sometimes interacts poorly with the
undo mechanism) or whenever the file is written (can be slow
when editing big diffs)."
  :type '(boolean))

85 86 87 88 89
(defcustom diff-advance-after-apply-hunk t
  "*Non-nil means `diff-apply-hunk' will move to the next hunk after applying."
  :type 'boolean)


90 91 92 93 94 95
(defvar diff-mode-hook nil
  "Run after setting up the `diff-mode' major mode.")

(defvar diff-outline-regexp
  "\\([*+][*+][*+] [^0-9]\\|@@ ...\\|\\*\\*\\* [0-9].\\|--- [0-9]..\\)")

96
;;;;
97
;;;; keymap, menu, ...
98
;;;;
99

100
(easy-mmode-defmap diff-mode-shared-map
101
  '(;; From Pavel Machek's patch-mode.
102 103 104 105 106 107
    ("n" . diff-hunk-next)
    ("N" . diff-file-next)
    ("p" . diff-hunk-prev)
    ("P" . diff-file-prev)
    ("k" . diff-hunk-kill)
    ("K" . diff-file-kill)
108
    ;; From compilation-minor-mode.
109 110
    ("}" . diff-file-next)
    ("{" . diff-file-prev)
111
    ("\C-m" . diff-goto-source)
112
    ([mouse-2] . diff-mouse-goto-source)
113
    ;; From XEmacs' diff-mode.
114 115 116 117 118 119 120 121 122 123 124
    ("W" . widen)
    ;;("." . diff-goto-source)		;display-buffer
    ;;("f" . diff-goto-source)		;find-file
    ("o" . diff-goto-source)		;other-window
    ;;("w" . diff-goto-source)		;other-frame
    ;;("N" . diff-narrow)
    ;;("h" . diff-show-header)
    ;;("j" . diff-show-difference)	;jump to Nth diff
    ;;("q" . diff-quit)
    (" " . scroll-up)
    ("\177" . scroll-down)
125
    ;; Our very own bindings.
126 127 128 129
    ("A" . diff-ediff-patch)
    ("r" . diff-restrict-view)
    ("R" . diff-reverse-direction)
    ("U" . diff-context->unified)
Benjamin Rutt's avatar
Benjamin Rutt committed
130 131
    ("C" . diff-unified->context)
    ("q" . quit-window))
132
  "Basic keymap for `diff-mode', bound to various prefix keys.")
133

134
(easy-mmode-defmap diff-mode-map
135
  `(("\e" . ,diff-mode-shared-map)
136 137 138
    ;; From compilation-minor-mode.
    ("\C-c\C-c" . diff-goto-source)
    ;; Misc operations.
139
    ("\C-c\C-s" . diff-split-hunk)
140 141
    ("\C-c\C-a" . diff-apply-hunk)
    ("\C-c\C-t" . diff-test-hunk))
142 143 144 145 146 147
  "Keymap for `diff-mode'.  See also `diff-mode-shared-map'.")

(easy-menu-define diff-mode-menu diff-mode-map
  "Menu for `diff-mode'."
  '("Diff"
    ["Jump to Source"		diff-goto-source	t]
148 149
    ["Apply hunk"		diff-apply-hunk		t]
    ["Apply diff with Ediff"	diff-ediff-patch	t]
150 151 152 153 154 155 156
    ["-----" nil nil]
    ["Reverse direction"	diff-reverse-direction	t]
    ["Context -> Unified"	diff-context->unified	t]
    ["Unified -> Context"	diff-unified->context	t]
    ;;["Fixup Headers"		diff-fixup-modifs	(not buffer-read-only)]
    ))

157
(defcustom diff-minor-mode-prefix "\C-c="
158
  "Prefix key for `diff-minor-mode' commands."
159
  :type '(choice (string "\e") (string "C-c=") string))
160

161 162
(easy-mmode-defmap diff-minor-mode-map
  `((,diff-minor-mode-prefix . ,diff-mode-shared-map))
163 164
  "Keymap for `diff-minor-mode'.  See also `diff-mode-shared-map'.")

165

166
;;;;
167
;;;; font-lock support
168
;;;;
169

Stefan Monnier's avatar
Stefan Monnier committed
170
(defface diff-header-face
171
  '((((type tty pc) (class color) (background light))
172
     (:foreground "blue1" :weight bold))
173
    (((type tty pc) (class color) (background dark))
174
     (:foreground "green" :weight bold))
175
    (((class color) (background light))
176
     (:background "grey85"))
177 178
    (((class color) (background dark))
     (:background "grey45"))
179
    (t (:weight bold)))
180
  "`diff-mode' face inherited by hunk and index header faces.")
Stefan Monnier's avatar
Stefan Monnier committed
181 182
(defvar diff-header-face 'diff-header-face)

183
(defface diff-file-header-face
184
  '((((type tty pc) (class color) (background light))
185
     (:foreground "yellow" :weight bold))
186
    (((type tty pc) (class color) (background dark))
187
     (:foreground "cyan" :weight bold))
188
    (((class color) (background light))
189
     (:background "grey70" :weight bold))
190
    (((class color) (background dark))
191 192
     (:background "grey60" :weight bold))
    (t (:weight bold)))			; :height 1.3
193
  "`diff-mode' face used to highlight file header lines.")
194 195 196
(defvar diff-file-header-face 'diff-file-header-face)

(defface diff-index-face
Stefan Monnier's avatar
Stefan Monnier committed
197
  '((t (:inherit diff-file-header-face)))
198
  "`diff-mode' face used to highlight index header lines.")
199 200 201
(defvar diff-index-face 'diff-index-face)

(defface diff-hunk-header-face
Stefan Monnier's avatar
Stefan Monnier committed
202
  '((t (:inherit diff-header-face)))
203
  "`diff-mode' face used to highlight hunk header lines.")
204 205 206
(defvar diff-hunk-header-face 'diff-hunk-header-face)

(defface diff-removed-face
Stefan Monnier's avatar
Stefan Monnier committed
207
  '((t (:inherit diff-changed-face)))
208
  "`diff-mode' face used to highlight removed lines.")
209 210 211
(defvar diff-removed-face 'diff-removed-face)

(defface diff-added-face
Stefan Monnier's avatar
Stefan Monnier committed
212
  '((t (:inherit diff-changed-face)))
213
  "`diff-mode' face used to highlight added lines.")
214 215 216
(defvar diff-added-face 'diff-added-face)

(defface diff-changed-face
217
  '((((type tty pc) (class color) (background light))
218
     (:foreground "magenta" :weight bold :slant italic))
219
    (((type tty pc) (class color) (background dark))
220
     (:foreground "yellow" :weight bold :slant italic))
221
    (t ()))
222
  "`diff-mode' face used to highlight changed lines.")
223 224
(defvar diff-changed-face 'diff-changed-face)

225 226
(defface diff-function-face
  '((t (:inherit diff-context-face)))
227
  "`diff-mode' face used to highlight function names produced by \"diff -p\".")
228 229
(defvar diff-function-face 'diff-function-face)

230 231 232 233 234 235
(defface diff-context-face
  '((((class color) (background light))
     (:foreground "grey50"))
    (((class color) (background dark))
     (:foreground "grey70"))
    (t ))
236
  "`diff-mode' face used to highlight context and other side-information.")
237
(defvar diff-context-face 'diff-context-face)
Stefan Monnier's avatar
Stefan Monnier committed
238

239
(defface diff-nonexistent-face
240
  '((t (:inherit diff-file-header-face)))
241
  "`diff-mode' face used to highlight nonexistent files in recursive diffs.")
242
(defvar diff-nonexistent-face 'diff-nonexistent-face)
243

244
(defvar diff-font-lock-keywords
Stefan Monnier's avatar
Stefan Monnier committed
245
  '(("^\\(@@ -[0-9,]+ \\+[0-9,]+ @@\\)\\(.*\\)$" ;unified
246
     (1 diff-hunk-header-face)
247
     (2 diff-function-face))
248
    ("^--- .+ ----$" . diff-hunk-header-face) ;context
249
    ("^\\(\\*\\{15\\}\\)\\(.*\\)$"	;context
250
     (1 diff-hunk-header-face)
251
     (2 diff-function-face))
252
    ("^\\*\\*\\* .+ \\*\\*\\*\\*". diff-hunk-header-face) ;context
253
    ("^\\(---\\|\\+\\+\\+\\|\\*\\*\\*\\) \\(\\S-+\\)\\(.*[^*-]\\)?\n"
Stefan Monnier's avatar
Stefan Monnier committed
254
     (0 diff-header-face) (2 diff-file-header-face prepend))
255 256 257 258
    ("^[0-9,]+[acd][0-9,]+$" . diff-hunk-header-face)
    ("^!.*\n" . diff-changed-face)	;context
    ("^[+>].*\n" . diff-added-face)
    ("^[-<].*\n" . diff-removed-face)
Stefan Monnier's avatar
Stefan Monnier committed
259
    ("^Index: \\(.+\\).*\n" (0 diff-header-face) (1 diff-index-face prepend))
260
    ("^Only in .*\n" . diff-nonexistent-face)
261
    ("^#.*" . font-lock-string-face)
262
    ("^[^-=+*!<>].*\n" . diff-context-face)))
263 264

(defconst diff-font-lock-defaults
265
  '(diff-font-lock-keywords t nil nil nil (font-lock-multiline . nil)))
266

267 268
(defvar diff-imenu-generic-expression
  ;; Prefer second name as first is most likely to be a backup or
269 270 271
  ;; version-control name.  The [\t\n] at the end of the unidiff pattern
  ;; catches Debian source diff files (which lack the trailing date).
  '((nil "\\+\\+\\+\\ \\([^\t\n]+\\)[\t\n]" 1) ; unidiffs
272 273
    (nil "^--- \\([^\t\n]+\\)\t.*\n\\*" 1))) ; context diffs

274
;;;;
275
;;;; Movement
276
;;;;
277

278
(defconst diff-hunk-header-re "^\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|\\*\\{15\\}.*\n\\*\\*\\* .+ \\*\\*\\*\\*\\|[0-9]+\\(,[0-9]+\\)?[acd][0-9]+\\(,[0-9]+\\)?\\)$")
279 280 281 282 283
(defconst diff-file-header-re (concat "^\\(--- .+\n\\+\\+\\+\\|\\*\\*\\* .+\n---\\|[^-+!<>0-9@* ]\\).+\n" (substring diff-hunk-header-re 1)))
(defvar diff-narrowed-to nil)

(defun diff-end-of-hunk (&optional style)
  (if (looking-at diff-hunk-header-re) (goto-char (match-end 0)))
284
  (let ((end (and (re-search-forward (case style
285 286 287
				       ;; A `unified' header is ambiguous.
				       (unified (concat "^[^-+# \\]\\|"
							diff-file-header-re))
288 289 290 291 292 293 294
				       (context "^[^-+#! \\]")
				       (normal "^[^<>#\\]")
				       (t "^[^-+#!<> \\]"))
				     nil t)
		  (match-beginning 0))))
    ;; The return value is used by easy-mmode-define-navigation.
    (goto-char (or end (point-max)))))
295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312

(defun diff-beginning-of-hunk ()
  (beginning-of-line)
  (unless (looking-at diff-hunk-header-re)
    (forward-line 1)
    (condition-case ()
	(re-search-backward diff-hunk-header-re)
      (error (error "Can't find the beginning of the hunk")))))

(defun diff-beginning-of-file ()
  (beginning-of-line)
  (unless (looking-at diff-file-header-re)
    (forward-line 2)
    (condition-case ()
	(re-search-backward diff-file-header-re)
      (error (error "Can't find the beginning of the file")))))

(defun diff-end-of-file ()
313 314
  (re-search-forward "^[-+#!<>0-9@* \\]" nil t)
  (re-search-forward "^[^-+#!<>0-9@* \\]" nil 'move)
315 316
  (beginning-of-line))

317 318
;; Define diff-{hunk,file}-{prev,next}
(easy-mmode-define-navigation
319
 diff-hunk diff-hunk-header-re "hunk" diff-end-of-hunk diff-restrict-view)
320 321
(easy-mmode-define-navigation
 diff-file diff-file-header-re "file" diff-end-of-hunk)
322 323 324 325 326 327 328 329 330 331 332 333 334

(defun diff-restrict-view (&optional arg)
  "Restrict the view to the current hunk.
If the prefix ARG is given, restrict the view to the current file instead."
  (interactive "P")
  (save-excursion
    (if arg (diff-beginning-of-file) (diff-beginning-of-hunk))
    (narrow-to-region (point)
		      (progn (if arg (diff-end-of-file) (diff-end-of-hunk))
			     (point)))
    (set (make-local-variable 'diff-narrowed-to) (if arg 'file 'hunk))))


335
(defun diff-hunk-kill ()
336 337 338
  "Kill current hunk."
  (interactive)
  (diff-beginning-of-hunk)
339 340 341 342 343 344 345
  (let* ((start (point))
	 (nexthunk (ignore-errors (diff-hunk-next) (point)))
	 (firsthunk (ignore-errors
		      (goto-char start)
		      (diff-beginning-of-file) (diff-hunk-next) (point)))
	 (nextfile (ignore-errors (diff-file-next) (point))))
    (goto-char start)
346 347 348
    (if (and firsthunk (= firsthunk start)
	     (or (null nexthunk)
		 (and nextfile (> nexthunk nextfile))))
349
	;; It's the only hunk for this file, so kill the file.
350
	(diff-file-kill)
351 352 353
      (diff-end-of-hunk)
      (kill-region start (point)))))

354
(defun diff-file-kill ()
355 356 357 358 359 360
  "Kill current file's hunks."
  (interactive)
  (diff-beginning-of-file)
  (let* ((start (point))
	 (prevhunk (save-excursion
		     (ignore-errors
361
		       (diff-hunk-prev) (point))))
362 363 364 365 366 367
	 (index (save-excursion
		  (re-search-backward "^Index: " prevhunk t))))
    (when index (setq start index))
    (diff-end-of-file)
    (kill-region start (point))))

368 369 370 371 372 373 374 375 376 377 378 379 380 381 382
(defun diff-kill-junk ()
  "Kill spurious empty diffs."
  (interactive)
  (save-excursion
    (let ((inhibit-read-only t))
      (goto-char (point-min))
      (while (re-search-forward (concat "^\\(Index: .*\n\\)"
					"\\([^-+!* <>].*\n\\)*?"
					"\\(\\(Index:\\) \\|"
					diff-file-header-re "\\)")
				nil t)
	(delete-region (if (match-end 4) (match-beginning 0) (match-end 1))
		       (match-beginning 3))
	(beginning-of-line)))))

383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408
(defun diff-count-matches (re start end)
  (save-excursion
    (let ((n 0))
      (goto-char start)
      (while (re-search-forward re end t) (incf n))
      n)))

(defun diff-split-hunk ()
  "Split the current (unified diff) hunk at point into two hunks."
  (interactive)
  (beginning-of-line)
  (let ((pos (point))
	(start (progn (diff-beginning-of-hunk) (point))))
    (unless (looking-at "@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@")
      (error "diff-split-hunk only works on unified context diffs"))
    (forward-line 1)
    (let* ((start1 (string-to-number (match-string 1)))
	   (start2 (string-to-number (match-string 2)))
	   (newstart1 (+ start1 (diff-count-matches "^[- \t]" (point) pos)))
	   (newstart2 (+ start2 (diff-count-matches "^[+ \t]" (point) pos))))
      (goto-char pos)
      ;; Hopefully the after-change-function will not screw us over.
      (insert "@@ -" (number-to-string newstart1) ",1 +"
	      (number-to-string newstart2) ",1 @@\n")
      ;; Fix the original hunk-header.
      (diff-fixup-modifs start pos))))
409

410

411 412 413 414
;;;;
;;;; jump to other buffers
;;;;

415 416
(defvar diff-remembered-files-alist nil)

417 418 419
(defun diff-filename-drop-dir (file)
  (when (string-match "/" file) (substring file (match-end 0))))

420 421 422
(defun diff-merge-strings (ancestor from to)
  "Merge the diff between ANCESTOR and FROM into TO.
Returns the merged string if successful or nil otherwise.
423
The strings are assumed not to contain any \"\\n\" (i.e. end of line).
424 425 426 427 428 429 430 431
If ANCESTOR = FROM, returns TO.
If ANCESTOR = TO, returns FROM.
The heuristic is simplistic and only really works for cases
like \(diff-merge-strings \"b/foo\" \"b/bar\" \"/a/c/foo\")."
  ;; Ideally, we want:
  ;;   AMB ANB CMD -> CND
  ;; but that's ambiguous if `foo' or `bar' is empty:
  ;; a/foo a/foo1 b/foo.c -> b/foo1.c but not 1b/foo.c or b/foo.c1
432
  (let ((str (concat ancestor "\n" from "\n" to)))
433
    (when (and (string-match (concat
434 435
			      "\\`\\(.*?\\)\\(.*\\)\\(.*\\)\n"
			      "\\1\\(.*\\)\\3\n"
436 437 438 439 440 441
			      "\\(.*\\(\\2\\).*\\)\\'") str)
	       (equal to (match-string 5 str)))
      (concat (substring str (match-beginning 5) (match-beginning 6))
	      (match-string 4 str)
	      (substring str (match-end 6) (match-end 5))))))

442 443 444 445 446 447 448 449 450
(defun diff-find-file-name (&optional old)
  "Return the file corresponding to the current patch.
Non-nil OLD means that we want the old file."
  (save-excursion
    (unless (looking-at diff-file-header-re)
      (or (ignore-errors (diff-beginning-of-file))
	  (re-search-forward diff-file-header-re nil t)))
    (let* ((limit (save-excursion
		   (condition-case ()
451
		       (progn (diff-hunk-prev) (point))
452
		     (error (point-min)))))
453
	   (header-files
454
	    (if (looking-at "[-*][-*][-*] \\(\\S-+\\)\\(\\s-.*\\)?\n[-+][-+][-+] \\(\\S-+\\)")
455 456
		(list (if old (match-string 1) (match-string 3))
		      (if old (match-string 3) (match-string 1)))
457
	      (forward-line 1) nil))
458 459 460 461
	   (fs (append
		(when (save-excursion
			(re-search-backward "^Index: \\(.+\\)" limit t))
		  (list (match-string 1)))
462
		header-files
463 464 465
		(when (re-search-backward "^diff \\(-\\S-+ +\\)*\\(\\S-+\\)\\( +\\(\\S-+\\)\\)?" nil t)
		  (list (if old (match-string 2) (match-string 4))
			(if old (match-string 4) (match-string 2))))))
466
	   (fs (delq nil fs)))
467
      (or
468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484
       ;; use any previously used preference
       (cdr (assoc fs diff-remembered-files-alist))
       ;; try to be clever and use previous choices as an inspiration
       (dolist (rf diff-remembered-files-alist)
	 (let ((newfile (diff-merge-strings (caar rf) (car fs) (cdr rf))))
	   (if (and newfile (file-exists-p newfile)) (return newfile))))
       ;; look for each file in turn.  If none found, try again but
       ;; ignoring the first level of directory, ...
       (do* ((files fs (delq nil (mapcar 'diff-filename-drop-dir files)))
	     (file nil nil))
	   ((or (null files)
		(setq file (do* ((files files (cdr files))
				 (file (car files) (car files)))
			       ((or (null file) (file-exists-p file))
				file))))
	    file))
       ;; <foo>.rej patches implicitly apply to <foo>
485 486 487
       (and (string-match "\\.rej\\'" (or buffer-file-name ""))
	    (let ((file (substring buffer-file-name 0 (match-beginning 0))))
	      (when (file-exists-p file) file)))
488 489 490 491 492
       ;; if all else fails, ask the user
       (let ((file (read-file-name (format "Use file %s: " (or (first fs) ""))
				   nil (first fs) t (first fs))))
	 (set (make-local-variable 'diff-remembered-files-alist)
	      (cons (cons fs file) diff-remembered-files-alist))
493 494
	 file)))))

495

496 497 498 499 500 501
(defun diff-mouse-goto-source (event)
  "Run `diff-goto-source' for the diff at a mouse click."
  (interactive "e")
  (save-excursion
    (mouse-set-point event)
    (diff-goto-source)))
502

503

504 505 506 507
(defun diff-ediff-patch ()
  "Call `ediff-patch-file' on the current buffer."
  (interactive)
  (condition-case err
508
      (ediff-patch-file nil (current-buffer))
509 510
    (wrong-number-of-arguments (ediff-patch-file))))

511
;;;;
512
;;;; Conversion functions
513
;;;;
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529

;;(defvar diff-inhibit-after-change nil
;;  "Non-nil means inhibit `diff-mode's after-change functions.")

(defun diff-unified->context (start end)
  "Convert unified diffs to context diffs.
START and END are either taken from the region (if a prefix arg is given) or
else cover the whole bufer."
  (interactive (if current-prefix-arg
		   (list (mark) (point))
		 (list (point-min) (point-max))))
  (unless (markerp end) (setq end (copy-marker end)))
  (let (;;(diff-inhibit-after-change t)
	(inhibit-read-only t))
    (save-excursion
      (goto-char start)
530
      (while (and (re-search-forward "^\\(\\(---\\) .+\n\\(\\+\\+\\+\\) .+\\|@@ -\\([0-9]+\\),\\([0-9]+\\) \\+\\([0-9]+\\),\\([0-9]+\\) @@.*\\)$" nil t)
531 532 533
		  (< (point) end))
	(combine-after-change-calls
	  (if (match-beginning 2)
534
	      ;; we matched a file header
535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
	      (progn
		;; use reverse order to make sure the indices are kept valid
		(replace-match "---" t t nil 3)
		(replace-match "***" t t nil 2))
	    ;; we matched a hunk header
	    (let ((line1 (match-string 4))
		  (lines1 (match-string 5))
		  (line2 (match-string 6))
		  (lines2 (match-string 7)))
	      (replace-match
	       (concat "***************\n*** " line1 ","
		       (number-to-string (+ (string-to-number line1)
					    (string-to-number lines1)
					    -1)) " ****"))
	      (forward-line 1)
	      (save-restriction
		(narrow-to-region (point)
				  (progn (diff-end-of-hunk 'unified) (point)))
		(let ((hunk (buffer-string)))
		  (goto-char (point-min))
		  (if (not (save-excursion (re-search-forward "^-" nil t)))
		      (delete-region (point) (point-max))
		    (goto-char (point-max))
		    (let ((modif nil) last-pt)
		      (while (progn (setq last-pt (point))
				    (= (forward-line -1) 0))
			(case (char-after)
			  (?  (insert " ") (setq modif nil) (backward-char 1))
			  (?+ (delete-region (point) last-pt) (setq modif t))
			  (?- (if (not modif)
				  (progn (forward-char 1)
					 (insert " "))
				(delete-char 1)
				(insert "! "))
			      (backward-char 2))
			  (?\\ (when (save-excursion (forward-line -1)
						     (= (char-after) ?+))
				 (delete-region (point) last-pt) (setq modif t)))
			  (t (setq modif nil))))))
		  (goto-char (point-max))
		  (save-excursion
		    (insert "--- " line2 ","
			    (number-to-string (+ (string-to-number line2)
						 (string-to-number lines2)
						 -1)) " ----\n" hunk))
		  ;;(goto-char (point-min))
		  (forward-line 1)
		  (if (not (save-excursion (re-search-forward "^+" nil t)))
		      (delete-region (point) (point-max))
		    (let ((modif nil) (delete nil))
		      (while (not (eobp))
			(case (char-after)
			  (?  (insert " ") (setq modif nil) (backward-char 1))
			  (?- (setq delete t) (setq modif t))
			  (?+ (if (not modif)
				  (progn (forward-char 1)
					 (insert " "))
				(delete-char 1)
				(insert "! "))
			      (backward-char 2))
			  (?\\ (when (save-excursion (forward-line 1)
						     (not (eobp)))
				 (setq delete t) (setq modif t)))
			  (t (setq modif nil)))
			(let ((last-pt (point)))
			  (forward-line 1)
			  (when delete
			    (delete-region last-pt (point))
			    (setq delete nil)))))))))))))))

(defun diff-context->unified (start end)
  "Convert context diffs to unified diffs.
START and END are either taken from the region (if a prefix arg is given) or
else cover the whole bufer."
  (interactive (if current-prefix-arg
		   (list (mark) (point))
		 (list (point-min) (point-max))))
  (unless (markerp end) (setq end (copy-marker end)))
  (let (;;(diff-inhibit-after-change t)
	(inhibit-read-only t))
    (save-excursion
      (goto-char start)
617
      (while (and (re-search-forward "^\\(\\(\\*\\*\\*\\) .+\n\\(---\\) .+\\|\\*\\{15\\}.*\n\\*\\*\\* \\([0-9]+\\),\\(-?[0-9]+\\) \\*\\*\\*\\*\\)$" nil t)
618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688
		  (< (point) end))
	(combine-after-change-calls
	  (if (match-beginning 2)
	      ;; we matched a file header
	      (progn
		;; use reverse order to make sure the indices are kept valid
		(replace-match "+++" t t nil 3)
		(replace-match "---" t t nil 2))
	    ;; we matched a hunk header
	    (let ((line1s (match-string 4))
		  (line1e (match-string 5))
		  (pt1 (match-beginning 0)))
	      (replace-match "")
	      (unless (re-search-forward
		       "^--- \\([0-9]+\\),\\(-?[0-9]+\\) ----$" nil t)
		(error "Can't find matching `--- n1,n2 ----' line"))
	      (let ((line2s (match-string 1))
		    (line2e (match-string 2))
		    (pt2 (progn
			   (delete-region (progn (beginning-of-line) (point))
					  (progn (forward-line 1) (point)))
			   (point-marker))))
		(goto-char pt1)
		(forward-line 1)
		(while (< (point) pt2)
		  (case (char-after)
		    ((?! ?-) (delete-char 2) (insert "-") (forward-line 1))
		    (?\ 		;merge with the other half of the chunk
		     (let* ((endline2
			     (save-excursion
			       (goto-char pt2) (forward-line 1) (point)))
			    (c (char-after pt2)))
		       (case c
			 ((?! ?+)
			  (insert "+"
				  (prog1 (buffer-substring (+ pt2 2) endline2)
				    (delete-region pt2 endline2))))
			 (?\ 		;FIXME: check consistency
			  (delete-region pt2 endline2)
			  (delete-char 1)
			  (forward-line 1))
			 (?\\ (forward-line 1))
			 (t (delete-char 1) (forward-line 1)))))
		    (t (forward-line 1))))
		(while (looking-at "[+! ] ")
		  (if (/= (char-after) ?!) (forward-char 1)
		    (delete-char 1) (insert "+"))
		  (delete-char 1) (forward-line 1))
		(save-excursion
		  (goto-char pt1)
		  (insert "@@ -" line1s ","
			  (number-to-string (- (string-to-number line1e)
					       (string-to-number line1s)
					       -1))
			  " +" line2s ","
			  (number-to-string (- (string-to-number line2e)
					       (string-to-number line2s)
					       -1)) " @@"))))))))))

(defun diff-reverse-direction (start end)
  "Reverse the direction of the diffs.
START and END are either taken from the region (if a prefix arg is given) or
else cover the whole bufer."
  (interactive (if current-prefix-arg
		   (list (mark) (point))
		 (list (point-min) (point-max))))
  (unless (markerp end) (setq end (copy-marker end)))
  (let (;;(diff-inhibit-after-change t)
	(inhibit-read-only t))
    (save-excursion
      (goto-char start)
689
      (while (and (re-search-forward "^\\(\\([-*][-*][-*] \\)\\(.+\\)\n\\([-+][-+][-+] \\)\\(.+\\)\\|\\*\\{15\\}.*\n\\*\\*\\* \\(.+\\) \\*\\*\\*\\*\\|@@ -\\([0-9,]+\\) \\+\\([0-9,]+\\) @@.*\\)$" nil t)
690 691 692 693 694 695 696 697 698 699 700 701
		  (< (point) end))
	(combine-after-change-calls
	  (cond
	   ;; a file header
	   ((match-beginning 2) (replace-match "\\2\\5\n\\4\\3" nil))
	   ;; a context-diff hunk header
	   ((match-beginning 6)
	    (let ((pt-lines1 (match-beginning 6))
		  (lines1 (match-string 6)))
	      (replace-match "" nil nil nil 6)
	      (forward-line 1)
	      (let ((half1s (point)))
702
		(while (looking-at "[-! \\][ \t]\\|#")
703 704
		  (when (= (char-after) ?-) (delete-char 1) (insert "+"))
		  (forward-line 1))
705
		(let ((half1 (delete-and-extract-region half1s (point))))
706 707 708 709 710 711 712
		  (unless (looking-at "^--- \\([0-9]+,-?[0-9]+\\) ----$")
		    (insert half1)
		    (error "Can't find matching `--- n1,n2 ----' line"))
		  (let ((str1 (match-string 1)))
		    (replace-match lines1 nil nil nil 1)
		    (forward-line 1)
		    (let ((half2s (point)))
713
		      (while (looking-at "[!+ \\][ \t]\\|#")
714 715
			(when (= (char-after) ?+) (delete-char 1) (insert "-"))
			(forward-line 1))
716
		      (let ((half2 (delete-and-extract-region half2s (point))))
717
			(insert (or half1 ""))
718
			(goto-char half1s)
719
			(insert (or half2 ""))))
720 721 722 723 724 725 726 727 728 729 730 731
		    (goto-char pt-lines1)
		    (insert str1))))))
	   ;; a unified-diff hunk header
	   ((match-beginning 7)
	    (replace-match "@@ -\\8 +\\7 @@" nil)
	    (forward-line 1)
	    (let ((c (char-after)) first last)
	      (while (case (setq c (char-after))
		       (?- (setq first (or first (point)))
			   (delete-char 1) (insert "+") t)
		       (?+ (setq last (or last (point)))
			   (delete-char 1) (insert "-") t)
732
		       ((?\\ ?#) t)
733
		       (t (when (and first last (< first last))
734
			    (insert (delete-and-extract-region first last)))
735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750
			  (setq first nil last nil)
			  (equal ?\  c)))
		(forward-line 1))))))))))

(defun diff-fixup-modifs (start end)
  "Fixup the hunk headers (in case the buffer was modified).
START and END are either taken from the region (if a prefix arg is given) or
else cover the whole bufer."
  (interactive (if current-prefix-arg
		   (list (mark) (point))
		 (list (point-min) (point-max))))
  (let ((inhibit-read-only t))
    (save-excursion
      (goto-char end) (diff-end-of-hunk)
      (let ((plus 0) (minus 0) (space 0) (bang 0))
	(while (and (= (forward-line -1) 0) (<= start (point)))
751
	  (if (not (looking-at "\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|[-*][-*][-*] .+ [-*][-*][-*][-*]\\)$"))
752 753 754 755 756
	      (case (char-after)
		(?\  (incf space))
		(?+ (incf plus))
		(?- (incf minus))
		(?! (incf bang))
757
		((?\\ ?#) nil)
758 759
		(t  (setq space 0 plus 0 minus 0 bang 0)))
	    (cond
760
	     ((looking-at "@@ -[0-9]+,\\([0-9]*\\) \\+[0-9]+,\\([0-9]*\\) @@.*$")
761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782
	      (let* ((old1 (match-string 1))
		     (old2 (match-string 2))
		     (new1 (number-to-string (+ space minus)))
		     (new2 (number-to-string (+ space plus))))
		(unless (string= new2 old2) (replace-match new2 t t nil 2))
		(unless (string= new1 old1) (replace-match new1 t t nil 1))))
	     ((looking-at "--- \\([0-9]+\\),\\([0-9]*\\) ----$")
	      (when (> (+ space bang plus) 0)
		(let* ((old1 (match-string 1))
		       (old2 (match-string 2))
		       (new (number-to-string
			     (+ space bang plus -1 (string-to-number old1)))))
		  (unless (string= new old2) (replace-match new t t nil 2)))))
	     ((looking-at "\\*\\*\\* \\([0-9]+\\),\\(-?[0-9]*\\) \\*\\*\\*\\*$")
	      (when (> (+ space bang minus) 0)
		(let* ((old (match-string 1))
		       (new (format
			     (concat "%0" (number-to-string (length old)) "d")
			     (+ space bang minus -1 (string-to-number old)))))
		  (unless (string= new old) (replace-match new t t nil 2))))))
	    (setq space 0 plus 0 minus 0 bang 0)))))))

783
;;;;
784
;;;; Hooks
785
;;;;
786 787 788 789 790 791 792 793 794 795 796 797 798

(defun diff-write-contents-hooks ()
  "Fixup hunk headers if necessary."
  (if (buffer-modified-p) (diff-fixup-modifs (point-min) (point-max)))
  nil)

;; It turns out that making changes in the buffer from within an
;; *-change-function is asking for trouble, whereas making them
;; from a post-command-hook doesn't pose much problems
(defvar diff-unhandled-changes nil)
(defun diff-after-change-function (beg end len)
  "Remember to fixup the hunk header.
See `after-change-functions' for the meaning of BEG, END and LEN."
799 800 801 802 803
  ;; Ignoring changes when inhibit-read-only is set is strictly speaking
  ;; incorrect, but it turns out that inhibit-read-only is normally not set
  ;; inside editing commands, while it tends to be set when the buffer gets
  ;; updated by an async process or by a conversion function, both of which
  ;; would rather not be uselessly slowed down by this hook.
804 805 806 807
  (when (and (not undo-in-progress) (not inhibit-read-only))
    (if diff-unhandled-changes
	(setq diff-unhandled-changes
	      (cons (min beg (car diff-unhandled-changes))
808
		    (max end (cdr diff-unhandled-changes))))
809 810 811 812 813 814 815
      (setq diff-unhandled-changes (cons beg end)))))

(defun diff-post-command-hook ()
  "Fixup hunk headers if necessary."
  (when (consp diff-unhandled-changes)
    (ignore-errors
      (save-excursion
816
	(goto-char (car diff-unhandled-changes))
817 818
	;; Maybe we've cut the end of the hunk before point.
	(if (and (bolp) (not (bobp))) (backward-char 1))
819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
	;; We used to fixup modifs on all the changes, but it turns out
	;; that it's safer not to do it on big changes, for example
	;; when yanking a big diff, since we might then screw up perfectly
	;; correct values.  -stef
	;; (unless (ignore-errors
	;; 	  (diff-beginning-of-hunk)
	;; 	  (save-excursion
	;; 	    (diff-end-of-hunk)
	;; 	    (> (point) (car diff-unhandled-changes))))
	;;   (goto-char (car diff-unhandled-changes))
	;; (re-search-forward diff-hunk-header-re (cdr diff-unhandled-changes))
	;;   (diff-beginning-of-hunk))
	;; (diff-fixup-modifs (point) (cdr diff-unhandled-changes))
	(diff-beginning-of-hunk)
	(when (save-excursion
		(diff-end-of-hunk)
835
		(>= (point) (cdr diff-unhandled-changes)))
836
	  (diff-fixup-modifs (point) (cdr diff-unhandled-changes)))))
837 838
    (setq diff-unhandled-changes nil)))

839
;;;;
840
;;;; The main function
841
;;;;
842 843

;;;###autoload
844
(define-derived-mode diff-mode fundamental-mode "Diff"
845
  "Major mode for viewing/editing context diffs.
846 847
Supports unified and context diffs as well as (to a lesser extent)
normal diffs.
848 849 850 851 852 853 854
When the buffer is read-only, the ESC prefix is not necessary.
IF you edit the buffer manually, diff-mode will try to update the hunk
headers for you on-the-fly.

You can also switch between context diff and unified diff with \\[diff-context->unified],
or vice versa with \\[diff-unified->context] and you can also revert the direction of
a diff with \\[diff-reverse-direction]."
855 856
  (set (make-local-variable 'font-lock-defaults) diff-font-lock-defaults)
  (set (make-local-variable 'outline-regexp) diff-outline-regexp)
857 858
  (set (make-local-variable 'imenu-generic-expression)
       diff-imenu-generic-expression)
859 860 861 862 863 864 865 866 867 868
  ;; These are not perfect.  They would be better done separately for
  ;; context diffs and unidiffs.
  ;; (set (make-local-variable 'paragraph-start)
  ;;        (concat "@@ "			; unidiff hunk
  ;; 	       "\\|\\*\\*\\* "		; context diff hunk or file start
  ;; 	       "\\|--- [^\t]+\t"))	; context or unidiff file
  ;; 					; start (first or second line)
  ;;   (set (make-local-variable 'paragraph-separate) paragraph-start)
  ;;   (set (make-local-variable 'page-delimiter) "--- [^\t]+\t")
  ;; compile support
869

870
  (when (and (> (point-max) (point-min)) diff-default-read-only)
871
    (toggle-read-only t))
872
  ;; setup change hooks
873
  (if (not diff-update-on-the-fly)
874
      (add-hook 'write-contents-functions 'diff-write-contents-hooks nil t)
875
    (make-local-variable 'diff-unhandled-changes)
876 877
    (add-hook 'after-change-functions 'diff-after-change-function nil t)
    (add-hook 'post-command-hook 'diff-post-command-hook nil t))
878
  ;; Neat trick from Dave Love to add more bindings in read-only mode:
879
  (add-to-list 'minor-mode-overriding-map-alist
880 881 882 883
  	       (cons 'buffer-read-only diff-mode-shared-map))
  ;; add-log support
  (set (make-local-variable 'add-log-current-defun-function)
       'diff-current-defun)
884 885
  (set (make-local-variable 'add-log-buffer-file-name-function)
       'diff-find-file-name))
886 887

;;;###autoload
888 889 890 891 892
(define-minor-mode diff-minor-mode
  "Minor mode for viewing/editing context diffs.
\\{diff-minor-mode-map}"
  nil " Diff" nil
  ;; FIXME: setup font-lock
893
  ;; setup change hooks
894
  (if (not diff-update-on-the-fly)
895
      (add-hook 'write-contents-functions 'diff-write-contents-hooks nil t)
896
    (make-local-variable 'diff-unhandled-changes)
897 898
    (add-hook 'after-change-functions 'diff-after-change-function nil t)
    (add-hook 'post-command-hook 'diff-post-command-hook nil t)))
899

900

901 902 903 904 905 906 907 908 909 910 911 912 913 914
;;;
;;; Misc operations that have proved useful at some point.
;;;

(defun diff-next-complex-hunk ()
  "Jump to the next \"complex\" hunk.
\"Complex\" is approximated by \"the hunk changes the number of lines\".
Only works for unified diffs."
  (interactive)
  (while
      (and (re-search-forward "^@@ [-0-9]+,\\([0-9]+\\) [+0-9]+,\\([0-9]+\\) @@"
			      nil t)
	   (equal (match-string 1) (match-string 2)))))

915 916 917 918 919
(defun diff-hunk-text (hunk destp char-offset)
  "Return the literal source text from HUNK as (TEXT . OFFSET).
if DESTP is nil TEXT is the source, otherwise the destination text.
CHAR-OFFSET is a char-offset in HUNK, and OFFSET is the corresponding
char-offset in TEXT."
920
  (with-temp-buffer
921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994
    (insert hunk)
    (goto-char (point-min))
    (let ((src-pos nil)
	  (dst-pos nil)
	  (divider-pos nil)
	  (num-pfx-chars 2))
      ;; Set the following variables:
      ;;  SRC-POS     buffer pos of the source part of the hunk or nil if none
      ;;  DST-POS     buffer pos of the destination part of the hunk or nil
      ;;  DIVIDER-POS buffer pos of any divider line separating the src & dst
      ;;  NUM-PFX-CHARS  number of line-prefix characters used by this format"
      (cond ((looking-at "^@@")
	     ;; unified diff
	     (setq num-pfx-chars 1)
	     (forward-line 1)
	     (setq src-pos (point) dst-pos (point)))
	    ((looking-at "^\\*\\*")
	     ;; context diff
	     (forward-line 2)
	     (setq src-pos (point))
	     (re-search-forward "^--- " nil t)
	     (forward-line 0)
	     (setq divider-pos (point))
	     (forward-line 1)
	     (setq dst-pos (point)))
	    ((looking-at "^[0-9]+a[0-9,]+$")
	     ;; normal diff, insert
	     (forward-line 1)
	     (setq dst-pos (point)))
	    ((looking-at "^[0-9,]+d[0-9]+$")
	     ;; normal diff, delete
	     (forward-line 1)
	     (setq src-pos (point)))
	    ((looking-at "^[0-9,]+c[0-9,]+$")
	     ;; normal diff, change
	     (forward-line 1)
	     (setq src-pos (point))
	     (re-search-forward "^---$" nil t)
	     (forward-line 0)
	     (setq divider-pos (point))
	     (forward-line 1)
	     (setq dst-pos (point)))
	    (t
	     (error "Unknown diff hunk type")))

      (if (if destp (null dst-pos) (null src-pos))
	  ;; Implied empty text
	  (if char-offset '("" . 0) "")

	;; For context diffs, either side can be empty, (if there's only
	;; added or only removed text).  We should then use the other side.
	(cond ((equal src-pos divider-pos) (setq src-pos dst-pos))
	      ((equal dst-pos (point-max)) (setq dst-pos src-pos)))

	(when char-offset (goto-char (+ (point-min) char-offset)))

	;; Get rid of anything except the desired text.
	(save-excursion
	  ;; Delete unused text region
	  (let ((keep (if destp dst-pos src-pos)))
	    (when (and divider-pos (> divider-pos keep))
	      (delete-region divider-pos (point-max)))
	    (delete-region (point-min) keep))
	  ;; Remove line-prefix characters, and unneeded lines (unified diffs).
	  (let ((kill-char (if destp ?- ?+)))
	    (goto-char (point-min))
	    (while (not (eobp))
	      (if (eq (char-after) kill-char)
		  (delete-region (point) (progn (forward-line 1) (point)))
		(delete-char num-pfx-chars)
		(forward-line 1)))))

	(let ((text (buffer-substring-no-properties (point-min) (point-max))))
	  (if char-offset (cons text (- (point) (point-min))) text))))))
995

996

Stefan Monnier's avatar
Stefan Monnier committed
997
(defun diff-find-text (text)
998
  "Return the buffer position (BEG . END) of the nearest occurrence of TEXT.
999 1000 1001
If TEXT isn't found, nil is returned."
  (let* ((orig (point))
	 (forw (and (search-forward text nil t)
1002
		    (cons (match-beginning 0) (match-end 0))))
1003 1004
	 (back (and (goto-char (+ orig (length text)))
		    (search-backward text nil t)
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
		    (cons (match-beginning 0) (match-end 0)))))
    ;; Choose the closest match.
    (if (and forw back)
	(if (> (- (car forw) orig) (- orig (car back))) back forw)
      (or back forw))))

(defun diff-find-approx-text (text)
  "Return the buffer position (BEG . END) of the nearest occurrence of TEXT.
Whitespace differences are ignored."
  (let* ((orig (point))
	 (re (concat "^[ \t\n]*"
		     (mapconcat 'regexp-quote (split-string text) "[ \t\n]+")
		     "[ \t\n]*\n"))
	 (forw (and (re-search-forward re nil t)
		    (cons (match-beginning 0) (match-end 0))))
	 (back (and (goto-char (+ orig (length text)))
		    (re-search-backward re nil t)
		    (cons (match-beginning 0) (match-end 0)))))
    ;; Choose the closest match.
1024
    (if (and forw back)
1025
	(if (> (- (car forw) orig) (- orig (car back))) back forw)
1026 1027
      (or back forw))))

1028 1029
(defsubst diff-xor (a b) (if a (not b) b))

Stefan Monnier's avatar
Stefan Monnier committed
1030
(defun diff-find-source-location (&optional other-file reverse)
1031 1032 1033 1034 1035 1036 1037 1038
  "Find out (BUF LINE-OFFSET POS SRC DST SWITCHED).
BUF is the buffer corresponding to the source file.
LINE-OFFSET is the offset between the expected and actual positions
  of the text of the hunk or nil if the text was not found.
POS is a pair (BEG . END) indicating the position of the text in the buffer.
SRC and DST are the two variants of text as returned by `diff-hunk-text'.
  SRC is the variant that was found in the buffer.
SWITCHED is non-nil if the patch is already applied."
Stefan Monnier's avatar
Stefan Monnier committed
1039
  (save-excursion
1040
    (let* ((other (diff-xor other-file diff-jump-to-old-file))
1041 1042 1043 1044 1045
	   (char-offset (- (point) (progn (diff-beginning-of-hunk) (point))))
	   (hunk (buffer-substring (point)
				   (save-excursion (diff-end-of-hunk) (point))))
	   (old (diff-hunk-text hunk reverse char-offset))
	   (new (diff-hunk-text hunk (not reverse) char-offset))
Stefan Monnier's avatar
Stefan Monnier committed
1046
	   ;; Find the location specification.
Stefan Monnier's avatar
Stefan Monnier committed
1047
	   (line (if (not (looking-at "\\(?:\\*\\{15\\}.*\n\\)?[-@* ]*\\([0-9,]+\\)\\([ acd+]+\\([0-9,]+\\)\\)?"))
1048 1049 1050 1051 1052 1053 1054 1055
		     (error "Can't find the hunk header")
		   (if other (match-string 1)
		     (if (match-end 3) (match-string 3)
		       (unless (re-search-forward "^--- \\([0-9,]+\\)" nil t)
			 (error "Can't find the hunk separator"))
		       (match-string 1)))))
	   (file (or (diff-find-file-name other) (error "Can't find the file")))
	   (buf (find-file-noselect file)))
Stefan Monnier's avatar
Stefan Monnier committed
1056 1057
      ;; Update the user preference if he so wished.
      (when (> (prefix-numeric-value other-file) 8)
1058
	(setq diff-jump-to-old-file other))
Stefan Monnier's avatar
Stefan Monnier committed
1059 1060 1061
      (with-current-buffer buf
	(goto-line (string-to-number line))
	(let* ((orig-pos (point))
1062 1063 1064 1065 1066 1067 1068 1069
	       (switched nil)
	       (pos (