diff-mode.el 50 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 42 43 44 45 46 47 48 49 50
;; - Add a `delete-after-apply' so C-c C-a automatically deletes hunks.
;;   Also allow C-c C-a to delete already-applied hunks.
;;
;; - Try `diff <file> <hunk>' to try and fuzzily discover the source location
;;   of a hunk.  Show then the changes between <file> and <hunk> and make it
;;   possible to apply them to <file>, <hunk-src>, or <hunk-dst>.
;;   Or maybe just make it into a ".rej to diff3-markers converter".
;;
;; - Refine hunk on a word-by-word basis.
;;
51
;; - Handle `diff -b' output in context->unified.
52 53 54 55 56 57 58

;;; Code:

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


(defgroup diff-mode ()
59
  "Major mode for viewing/editing diffs"
60
  :version "21.1"
61 62 63
  :group 'tools
  :group 'diff)

64
(defcustom diff-default-read-only nil
65 66 67 68
  "If non-nil, `diff-mode' buffers default to being read-only."
  :type 'boolean
  :group 'diff-mode)

69
(defcustom diff-jump-to-old-file nil
70 71 72 73
  "*Non-nil means `diff-goto-source' jumps to the old file.
Else, it jumps to the new file."
  :type '(boolean))

74
(defcustom diff-update-on-the-fly t
75 76 77 78 79 80 81 82
  "*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))

83 84 85 86 87
(defcustom diff-advance-after-apply-hunk t
  "*Non-nil means `diff-apply-hunk' will move to the next hunk after applying."
  :type 'boolean)


88 89 90 91
(defcustom diff-mode-hook nil
  "Run after setting up the `diff-mode' major mode."
  :type 'hook
  :options '(diff-delete-empty-files diff-make-unified))
92 93 94 95

(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-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-r" . diff-refine-hunk)
140
    ("\C-c\C-s" . diff-split-hunk)
141 142
    ("\C-c\C-a" . diff-apply-hunk)
    ("\C-c\C-t" . diff-test-hunk))
143 144 145 146 147 148
  "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]
149 150
    ["Apply hunk"		diff-apply-hunk		t]
    ["Apply diff with Ediff"	diff-ediff-patch	t]
151 152 153 154 155 156 157
    ["-----" 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)]
    ))

158
(defcustom diff-minor-mode-prefix "\C-c="
159
  "Prefix key for `diff-minor-mode' commands."
160
  :type '(choice (string "\e") (string "C-c=") string))
161

162 163
(easy-mmode-defmap diff-minor-mode-map
  `((,diff-minor-mode-prefix . ,diff-mode-shared-map))
164 165
  "Keymap for `diff-minor-mode'.  See also `diff-mode-shared-map'.")

166

167
;;;;
168
;;;; font-lock support
169
;;;;
170

Stefan Monnier's avatar
Stefan Monnier committed
171
(defface diff-header-face
172
  '((((type tty pc) (class color) (background light))
173
     (:foreground "blue1" :weight bold))
174
    (((type tty pc) (class color) (background dark))
175
     (:foreground "green" :weight bold))
176
    (((class color) (background light))
177
     (:background "grey85"))
178 179
    (((class color) (background dark))
     (:background "grey45"))
180
    (t (:weight bold)))
181
  "`diff-mode' face inherited by hunk and index header faces.")
Stefan Monnier's avatar
Stefan Monnier committed
182 183
(defvar diff-header-face 'diff-header-face)

184
(defface diff-file-header-face
185
  '((((type tty pc) (class color) (background light))
186
     (:foreground "yellow" :weight bold))
187
    (((type tty pc) (class color) (background dark))
188
     (:foreground "cyan" :weight bold))
189
    (((class color) (background light))
190
     (:background "grey70" :weight bold))
191
    (((class color) (background dark))
192 193
     (:background "grey60" :weight bold))
    (t (:weight bold)))			; :height 1.3
194
  "`diff-mode' face used to highlight file header lines.")
195 196 197
(defvar diff-file-header-face 'diff-file-header-face)

(defface diff-index-face
Stefan Monnier's avatar
Stefan Monnier committed
198
  '((t (:inherit diff-file-header-face)))
199
  "`diff-mode' face used to highlight index header lines.")
200 201 202
(defvar diff-index-face 'diff-index-face)

(defface diff-hunk-header-face
Stefan Monnier's avatar
Stefan Monnier committed
203
  '((t (:inherit diff-header-face)))
204
  "`diff-mode' face used to highlight hunk header lines.")
205 206 207
(defvar diff-hunk-header-face 'diff-hunk-header-face)

(defface diff-removed-face
Stefan Monnier's avatar
Stefan Monnier committed
208
  '((t (:inherit diff-changed-face)))
209
  "`diff-mode' face used to highlight removed lines.")
210 211 212
(defvar diff-removed-face 'diff-removed-face)

(defface diff-added-face
Stefan Monnier's avatar
Stefan Monnier committed
213
  '((t (:inherit diff-changed-face)))
214
  "`diff-mode' face used to highlight added lines.")
215 216 217
(defvar diff-added-face 'diff-added-face)

(defface diff-changed-face
218
  '((((type tty pc) (class color) (background light))
219
     (:foreground "magenta" :weight bold :slant italic))
220
    (((type tty pc) (class color) (background dark))
221
     (:foreground "yellow" :weight bold :slant italic))
222
    (t ()))
223
  "`diff-mode' face used to highlight changed lines.")
224 225
(defvar diff-changed-face 'diff-changed-face)

226 227
(defface diff-function-face
  '((t (:inherit diff-context-face)))
228
  "`diff-mode' face used to highlight function names produced by \"diff -p\".")
229 230
(defvar diff-function-face 'diff-function-face)

231 232 233 234 235 236
(defface diff-context-face
  '((((class color) (background light))
     (:foreground "grey50"))
    (((class color) (background dark))
     (:foreground "grey70"))
    (t ))
237
  "`diff-mode' face used to highlight context and other side-information.")
238
(defvar diff-context-face 'diff-context-face)
Stefan Monnier's avatar
Stefan Monnier committed
239

240
(defface diff-nonexistent-face
241
  '((t (:inherit diff-file-header-face)))
242
  "`diff-mode' face used to highlight nonexistent files in recursive diffs.")
243
(defvar diff-nonexistent-face 'diff-nonexistent-face)
244

245 246
(defconst diff-yank-handler '(diff-yank-function))
(defun diff-yank-function (text)
247 248 249
  ;; FIXME: the yank-handler is now called separately on each piece of text
  ;; with a yank-handler property, so the next-single-property-change call
  ;; below will always return nil :-(   --stef
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
  (let ((mixed (next-single-property-change 0 'yank-handler text))
	(start (point)))
    ;; First insert the text.
    (insert text)
    ;; If the text does not include any diff markers and if we're not
    ;; yanking back into a diff-mode buffer, get rid of the prefixes.
    (unless (or mixed (derived-mode-p 'diff-mode))
      (undo-boundary)		; Just in case the user wanted the prefixes.
      (let ((re (save-excursion
		  (if (re-search-backward "^[><!][ \t]" start t)
		      (if (eq (char-after) ?!)
			  "^[!+- ][ \t]" "^[<>][ \t]")
		    "^[ <>!+-]"))))
	(save-excursion
	  (while (re-search-backward re start t)
	    (replace-match "" t t)))))))
	

268
(defvar diff-font-lock-keywords
269
  `(("^\\(@@ -[0-9,]+ \\+[0-9,]+ @@\\)\\(.*\\)$" ;unified
270
     (1 diff-hunk-header-face)
271
     (2 diff-function-face))
272
    ("^--- .+ ----$" . diff-hunk-header-face) ;context
273
    ("^\\(\\*\\{15\\}\\)\\(.*\\)$"	;context
274
     (1 diff-hunk-header-face)
275
     (2 diff-function-face))
276
    ("^\\*\\*\\* .+ \\*\\*\\*\\*". diff-hunk-header-face) ;context
277
    ("^\\(---\\|\\+\\+\\+\\|\\*\\*\\*\\) \\(\\S-+\\)\\(.*[^*-]\\)?\n"
Stefan Monnier's avatar
Stefan Monnier committed
278
     (0 diff-header-face) (2 diff-file-header-face prepend))
279
    ("^[0-9,]+[acd][0-9,]+$" . diff-hunk-header-face)
280 281 282
    ("^!.*\n" (0 diff-changed-face))
    ("^[+>].*\n" (0 diff-added-face))
    ("^[-<].*\n" (0 diff-removed-face))
Stefan Monnier's avatar
Stefan Monnier committed
283
    ("^Index: \\(.+\\).*\n" (0 diff-header-face) (1 diff-index-face prepend))
284
    ("^Only in .*\n" . diff-nonexistent-face)
285
    ("^#.*" . font-lock-string-face)
286
    ("^[^-=+*!<>].*\n" (0 diff-context-face))))
287 288

(defconst diff-font-lock-defaults
289
  '(diff-font-lock-keywords t nil nil nil (font-lock-multiline . nil)))
290

291 292
(defvar diff-imenu-generic-expression
  ;; Prefer second name as first is most likely to be a backup or
293 294 295
  ;; 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
296 297
    (nil "^--- \\([^\t\n]+\\)\t.*\n\\*" 1))) ; context diffs

298
;;;;
299
;;;; Movement
300
;;;;
301

302
(defconst diff-hunk-header-re "^\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|\\*\\{15\\}.*\n\\*\\*\\* .+ \\*\\*\\*\\*\\|[0-9]+\\(,[0-9]+\\)?[acd][0-9]+\\(,[0-9]+\\)?\\)$")
303 304 305 306
(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)
307 308 309 310 311
  (when (looking-at diff-hunk-header-re)
    (unless style
      ;; Especially important for unified (because headers are ambiguous).
      (setq style (cdr (assq (char-after) '((?@ . unified) (?* . context))))))
    (goto-char (match-end 0)))
312
  (let ((end (and (re-search-forward (case style
313 314 315
				       ;; A `unified' header is ambiguous.
				       (unified (concat "^[^-+# \\]\\|"
							diff-file-header-re))
316 317 318 319 320 321 322
				       (context "^[^-+#! \\]")
				       (normal "^[^<>#\\]")
				       (t "^[^-+#!<> \\]"))
				     nil t)
		  (match-beginning 0))))
    ;; The return value is used by easy-mmode-define-navigation.
    (goto-char (or end (point-max)))))
323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340

(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 ()
341
  (re-search-forward "^[-+#!<>0-9@* \\]" nil t)
342 343 344 345 346
  (re-search-forward (concat "^[^-+#!<>0-9@* \\]\\|" diff-file-header-re)
		     nil 'move)
  (if (match-beginning 1)
      (goto-char (match-beginning 1))
    (beginning-of-line)))
347

348 349
;; Define diff-{hunk,file}-{prev,next}
(easy-mmode-define-navigation
350
 diff-hunk diff-hunk-header-re "hunk" diff-end-of-hunk diff-restrict-view)
351 352
(easy-mmode-define-navigation
 diff-file diff-file-header-re "file" diff-end-of-hunk)
353 354 355 356 357 358 359 360 361 362 363 364 365

(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))))


366
(defun diff-hunk-kill ()
367 368 369
  "Kill current hunk."
  (interactive)
  (diff-beginning-of-hunk)
370
  (let* ((start (point))
371 372
	 (nexthunk (when (re-search-forward diff-hunk-header-re nil t)
		     (match-beginning 0)))
373 374 375 376 377
	 (firsthunk (ignore-errors
		      (goto-char start)
		      (diff-beginning-of-file) (diff-hunk-next) (point)))
	 (nextfile (ignore-errors (diff-file-next) (point))))
    (goto-char start)
378 379 380
    (if (and firsthunk (= firsthunk start)
	     (or (null nexthunk)
		 (and nextfile (> nexthunk nextfile))))
381
	;; It's the only hunk for this file, so kill the file.
382
	(diff-file-kill)
383 384 385
      (diff-end-of-hunk)
      (kill-region start (point)))))

386
(defun diff-file-kill ()
387 388 389 390 391 392
  "Kill current file's hunks."
  (interactive)
  (diff-beginning-of-file)
  (let* ((start (point))
	 (prevhunk (save-excursion
		     (ignore-errors
393
		       (diff-hunk-prev) (point))))
394 395 396 397
	 (index (save-excursion
		  (re-search-backward "^Index: " prevhunk t))))
    (when index (setq start index))
    (diff-end-of-file)
398
    (if (looking-at "^\n") (forward-char 1)) ;`tla' generates such diffs.
399 400
    (kill-region start (point))))

401 402 403 404 405 406 407 408 409 410 411 412 413 414 415
(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)))))

416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441
(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))))
442

443

444 445 446 447
;;;;
;;;; jump to other buffers
;;;;

448 449
(defvar diff-remembered-files-alist nil)

450 451 452
(defun diff-filename-drop-dir (file)
  (when (string-match "/" file) (substring file (match-end 0))))

453 454 455
(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.
456
The strings are assumed not to contain any \"\\n\" (i.e. end of line).
457 458 459 460 461 462 463 464
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
465
  (let ((str (concat ancestor "\n" from "\n" to)))
466
    (when (and (string-match (concat
467 468
			      "\\`\\(.*?\\)\\(.*\\)\\(.*\\)\n"
			      "\\1\\(.*\\)\\3\n"
469 470 471 472 473 474
			      "\\(.*\\(\\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))))))

475 476 477 478 479 480 481 482 483 484 485 486 487 488 489
(defun diff-tell-file-name (old name)
  "Tell Emacs where the find the source file of the current hunk.
If the OLD prefix arg is passed, tell the file NAME of the old file."
  (interactive
   (let* ((old current-prefix-arg)
	  (fs (diff-hunk-file-names current-prefix-arg)))
     (unless fs (error "No file name to look for"))
     (list old (read-file-name (format "File for %s: " (car fs))
			       nil (diff-find-file-name old) t))))
  (let ((fs (diff-hunk-file-names old)))
    (unless fs (error "No file name to look for"))
    (push (cons fs name) diff-remembered-files-alist)))
  
(defun diff-hunk-file-names (&optional old)
  "Give the list of file names textually mentioned for the current hunk."
490 491 492 493
  (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)))
494
    (let ((limit (save-excursion
495
		   (condition-case ()
496
		       (progn (diff-hunk-prev) (point))
497
		     (error (point-min)))))
498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523
	  (header-files
	   (if (looking-at "[-*][-*][-*] \\(\\S-+\\)\\(\\s-.*\\)?\n[-+][-+][-+] \\(\\S-+\\)")
	       (list (if old (match-string 1) (match-string 3))
		     (if old (match-string 3) (match-string 1)))
	     (forward-line 1) nil)))
      (delq nil
	    (append
	     (when (and (not old)
			(save-excursion
			  (re-search-backward "^Index: \\(.+\\)" limit t)))
	       (list (match-string 1)))
	     header-files
	     (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)))))))))

(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 ((fs (diff-hunk-file-names old)))
524
      (or
525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541
       ;; 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>
542 543 544
       (and (string-match "\\.rej\\'" (or buffer-file-name ""))
	    (let ((file (substring buffer-file-name 0 (match-beginning 0))))
	      (when (file-exists-p file) file)))
545 546 547 548 549
       ;; 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))
550 551
	 file)))))

552

553 554 555 556
(defun diff-ediff-patch ()
  "Call `ediff-patch-file' on the current buffer."
  (interactive)
  (condition-case err
557
      (ediff-patch-file nil (current-buffer))
558 559
    (wrong-number-of-arguments (ediff-patch-file))))

560
;;;;
561
;;;; Conversion functions
562
;;;;
563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578

;;(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)
579
      (while (and (re-search-forward "^\\(\\(---\\) .+\n\\(\\+\\+\\+\\) .+\\|@@ -\\([0-9]+\\),\\([0-9]+\\) \\+\\([0-9]+\\),\\([0-9]+\\) @@.*\\)$" nil t)
580 581 582
		  (< (point) end))
	(combine-after-change-calls
	  (if (match-beginning 2)
583
	      ;; we matched a file header
584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
	      (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)
666
      (while (and (re-search-forward "^\\(\\(\\*\\*\\*\\) .+\n\\(---\\) .+\\|\\*\\{15\\}.*\n\\*\\*\\* \\([0-9]+\\),\\(-?[0-9]+\\) \\*\\*\\*\\*\\)$" nil t)
667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737
		  (< (point) end))
	(combine-after-change-calls
	  (if (match-beginning 2)
	      ;; we matched a file header
	      (progn
		;; use reverse order to make sure the indices are kept valid
		(replace-match "+++" t t nil 3)
		(replace-match "---" t t nil 2))
	    ;; we matched a hunk header
	    (let ((line1s (match-string 4))
		  (line1e (match-string 5))
		  (pt1 (match-beginning 0)))
	      (replace-match "")
	      (unless (re-search-forward
		       "^--- \\([0-9]+\\),\\(-?[0-9]+\\) ----$" 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)
738
      (while (and (re-search-forward "^\\(\\([-*][-*][-*] \\)\\(.+\\)\n\\([-+][-+][-+] \\)\\(.+\\)\\|\\*\\{15\\}.*\n\\*\\*\\* \\(.+\\) \\*\\*\\*\\*\\|@@ -\\([0-9,]+\\) \\+\\([0-9,]+\\) @@.*\\)$" nil t)
739 740 741 742 743 744 745 746 747 748 749 750
		  (< (point) end))
	(combine-after-change-calls
	  (cond
	   ;; a file header
	   ((match-beginning 2) (replace-match "\\2\\5\n\\4\\3" nil))
	   ;; a context-diff hunk header
	   ((match-beginning 6)
	    (let ((pt-lines1 (match-beginning 6))
		  (lines1 (match-string 6)))
	      (replace-match "" nil nil nil 6)
	      (forward-line 1)
	      (let ((half1s (point)))
751
		(while (looking-at "[-! \\][ \t]\\|#")
752 753
		  (when (= (char-after) ?-) (delete-char 1) (insert "+"))
		  (forward-line 1))
754
		(let ((half1 (delete-and-extract-region half1s (point))))
755 756 757 758 759 760 761
		  (unless (looking-at "^--- \\([0-9]+,-?[0-9]+\\) ----$")
		    (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)))
762
		      (while (looking-at "[!+ \\][ \t]\\|#")
763 764
			(when (= (char-after) ?+) (delete-char 1) (insert "-"))
			(forward-line 1))
765
		      (let ((half2 (delete-and-extract-region half2s (point))))
766
			(insert (or half1 ""))
767
			(goto-char half1s)
768
			(insert (or half2 ""))))
769 770 771 772 773 774 775 776 777 778 779 780
		    (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)
781
		       ((?\\ ?#) t)
782
		       (t (when (and first last (< first last))
783
			    (insert (delete-and-extract-region first last)))
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799
			  (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)))
800
	  (if (not (looking-at "\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|[-*][-*][-*] .+ [-*][-*][-*][-*]\\)$"))
801 802 803 804 805
	      (case (char-after)
		(?\  (incf space))
		(?+ (incf plus))
		(?- (incf minus))
		(?! (incf bang))
806
		((?\\ ?#) nil)
807 808
		(t  (setq space 0 plus 0 minus 0 bang 0)))
	    (cond
809
	     ((looking-at "@@ -[0-9]+,\\([0-9]*\\) \\+[0-9]+,\\([0-9]*\\) @@.*$")
810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
	      (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)))))))

832
;;;;
833
;;;; Hooks
834
;;;;
835 836 837 838 839 840 841 842 843 844 845 846 847

(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."
848 849 850 851 852
  ;; 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.
853 854 855 856
  (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))
857
		    (max end (cdr diff-unhandled-changes))))
858 859 860 861 862 863 864
      (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
865
	(goto-char (car diff-unhandled-changes))
866 867
	;; Maybe we've cut the end of the hunk before point.
	(if (and (bolp) (not (bobp))) (backward-char 1))
868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883
	;; 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)
884
		(>= (point) (cdr diff-unhandled-changes)))
885
	  (diff-fixup-modifs (point) (cdr diff-unhandled-changes)))))
886 887
    (setq diff-unhandled-changes nil)))

Stefan Monnier's avatar
Stefan Monnier committed
888 889 890 891 892 893 894 895
(defun diff-next-error (arg reset)
  ;; Select a window that displays the current buffer so that point
  ;; movements are reflected in that window.  Otherwise, the user might
  ;; never see the hunk corresponding to the source she's jumping to.
  (pop-to-buffer (current-buffer))
  (if reset (goto-char (point-min)))
  (diff-hunk-next arg)
  (diff-goto-source))
896 897

;;;###autoload
898
(define-derived-mode diff-mode fundamental-mode "Diff"
899
  "Major mode for viewing/editing context diffs.
900 901
Supports unified and context diffs as well as (to a lesser extent)
normal diffs.
902 903 904 905 906 907 908
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]."
909 910
  (set (make-local-variable 'font-lock-defaults) diff-font-lock-defaults)
  (set (make-local-variable 'outline-regexp) diff-outline-regexp)
911 912
  (set (make-local-variable 'imenu-generic-expression)
       diff-imenu-generic-expression)
913 914 915 916 917 918 919 920 921 922
  ;; 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
Stefan Monnier's avatar
Stefan Monnier committed
923
  (set (make-local-variable 'next-error-function) 'diff-next-error)
924

925
  (when (and (> (point-max) (point-min)) diff-default-read-only)
926
    (toggle-read-only t))
927
  ;; setup change hooks
928
  (if (not diff-update-on-the-fly)
929
      (add-hook 'write-contents-functions 'diff-write-contents-hooks nil t)
930
    (make-local-variable 'diff-unhandled-changes)
931 932
    (add-hook 'after-change-functions 'diff-after-change-function nil t)
    (add-hook 'post-command-hook 'diff-post-command-hook nil t))
933
  ;; Neat trick from Dave Love to add more bindings in read-only mode:
934 935 936 937 938 939
  (let ((ro-bind (cons 'buffer-read-only diff-mode-shared-map)))
    (add-to-list 'minor-mode-overriding-map-alist ro-bind)
    ;; Turn off this little trick in case the buffer is put in view-mode.
    (add-hook 'view-mode-hook
	      `(lambda ()
		 (setq minor-mode-overriding-map-alist
940
		       (delq ',ro-bind minor-mode-overriding-map-alist)))
941
	      nil t))
942 943 944
  ;; add-log support
  (set (make-local-variable 'add-log-current-defun-function)
       'diff-current-defun)
945 946
  (set (make-local-variable 'add-log-buffer-file-name-function)
       'diff-find-file-name))
947 948

;;;###autoload
949 950 951 952 953
(define-minor-mode diff-minor-mode
  "Minor mode for viewing/editing context diffs.
\\{diff-minor-mode-map}"
  nil " Diff" nil
  ;; FIXME: setup font-lock
954
  ;; setup change hooks
955
  (if (not diff-update-on-the-fly)
956
      (add-hook 'write-contents-functions 'diff-write-contents-hooks nil t)
957
    (make-local-variable 'diff-unhandled-changes)
958 959
    (add-hook 'after-change-functions 'diff-after-change-function nil t)
    (add-hook 'post-command-hook 'diff-post-command-hook nil t)))
960

961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983
;;; Handy hook functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun diff-delete-if-empty ()
  ;; An empty diff file means there's no more diffs to integrate, so we
  ;; can just remove the file altogether.  Very handy for .rej files if we
  ;; remove hunks as we apply them.
  (when (and buffer-file-name
	     (eq 0 (nth 7 (file-attributes buffer-file-name))))
    (delete-file buffer-file-name)))

(defun diff-delete-empty-files ()
  "Arrange for empty diff files to be removed."
  (add-hook 'after-save-hook 'diff-delete-if-empty nil t))

(defun diff-make-unified ()
  "Turn context diffs into unified diffs if applicable."
  (if (save-excursion
	(goto-char (point-min))
	(looking-at "\\*\\*\\* "))
      (let ((mod (buffer-modified-p)))
	(unwind-protect
	    (diff-context->unified (point-min) (point-max))
	  (restore-buffer-modified-p mod)))))
984

985 986 987 988 989 990 991 992 993 994 995 996 997 998
;;;
;;; 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)))))

999 1000 1001 1002 1003
(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."
1004
  (with-temp-buffer
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078
    (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))))))
1079

1080

Stefan Monnier's avatar
Stefan Monnier committed
1081
(defun diff-find-text (text)
1082
  "Return the buffer position (BEG . END) of the nearest occurrence of TEXT.
1083 1084 1085
If TEXT isn't found, nil is returned."
  (let* ((orig (point))
	 (forw (and (search-forward text nil t)
1086
		    (cons (match-beginning 0) (match-end 0))))
1087 1088
	 (back (and (goto-char (+ orig (length text)))
		    (search-backward text nil t)
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107
		    (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*