lisp/diff-mode.el

   1 ;;; diff-mode.el --- A mode for viewing/editing context diffs
   2
   3 ;; Copyright (C) 1998, 1999, 2000  Free Software Foundation, Inc.
   4
   5 ;; Author: Stefan Monnier <monnier@cs.yale.edu>
   6 ;; Keywords: patch diff
   7 ;; Revision: $Id: diff-mode.el,v 1.26 2000/10/02 06:49:21 miles Exp $
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; Provides support for font-lock patterns, outline-regexps, navigation
  29 ;; commands, editing and various conversions as well as jumping
  30 ;; to the corresponding source file.
  31
  32 ;; inspired by Pavel Machek's patch-mode.el (<pavel@atrey.karlin.mff.cuni.cz>)
  33 ;; some efforts were spent to have it somewhat compatible with XEmacs'
  34 ;; diff-mode as well as with compilation-minor-mode
  35
  36 ;; to use it, simply add to your .emacs the following lines:
  37 ;;
  38 ;; (autoload 'diff-mode "diff-mode" "Diff major mode" t)
  39 ;; (add-to-list 'auto-mode-alist '("\\.\\(diffs?\\|patch\\|rej\\)\\'" . diff-mode))
  40
  41 ;; Bugs:
  42
  43 ;; - Reverse doesn't work with normal diffs.
  44
  45 ;; Todo:
  46
  47 ;; - Spice up the minor-mode with font-lock support.
  48 ;; - Improve narrowed-view support.
  49 ;; - Improve the `compile' support (?).
  50 ;; - Recognize pcl-cvs' special string for `cvs-execute-single'.
  51 ;; - Support for # comments in context->unified.
  52 ;; - Do a fuzzy search in diff-goto-source.
  53 ;; - Allow diff.el to use diff-mode.
  54 ;;   This mostly means ability to jump from half-hunk to half-hunk
  55 ;;   in context (and normal) diffs and to jump to the corresponding
  56 ;;   (i.e. new or old) file.
  57 ;; - Handle `diff -b' output in context->unified.
  58
  59 ;;; Code:
  60
  61 (eval-when-compile (require 'cl))
  62
  63
  64 (defgroup diff-mode ()
  65   "Major mode for viewing/editing diffs"
  66   :version "21.1"
  67   :group 'tools
  68   :group 'diff)
  69
  70 (defcustom diff-jump-to-old-file-flag nil
  71   "*Non-nil means `diff-goto-source' jumps to the old file.
  72 Else, it jumps to the new file."
  73   :group 'diff-mode
  74   :type '(boolean))
  75
  76 (defcustom diff-update-on-the-fly-flag t
  77   "*Non-nil means hunk headers are kept up-to-date on-the-fly.
  78 When editing a diff file, the line numbers in the hunk headers
  79 need to be kept consistent with the actual diff.  This can
  80 either be done on the fly (but this sometimes interacts poorly with the
  81 undo mechanism) or whenever the file is written (can be slow
  82 when editing big diffs)."
  83   :group 'diff-mode
  84   :type '(boolean))
  85
  86 (defcustom diff-advance-after-apply-hunk t
  87   "*Non-nil means `diff-apply-hunk' will move to the next hunk after applying."
  88   :group 'diff-mode
  89   :type 'boolean)
  90
  91
  92 (defvar diff-mode-hook nil
  93   "Run after setting up the `diff-mode' major mode.")
  94
  95 (defvar diff-outline-regexp
  96   "\\([*+][*+][*+] [^0-9]\\|@@ ...\\|\\*\\*\\* [0-9].\\|--- [0-9]..\\)")
  97
  98 ;;;;
  99 ;;;; keymap, menu, ...
 100 ;;;;
 101
 102 (easy-mmode-defmap diff-mode-shared-map
 103   '(;; From Pavel Machek's patch-mode.
 104     ("n" . diff-hunk-next)
 105     ("N" . diff-file-next)
 106     ("p" . diff-hunk-prev)
 107     ("P" . diff-file-prev)
 108     ("k" . diff-hunk-kill)
 109     ("K" . diff-file-kill)
 110     ;; From compilation-minor-mode.
 111     ("}" . diff-file-next)
 112     ("{" . diff-file-prev)
 113     ("\C-m" . diff-goto-source)
 114     ([mouse-2] . diff-mouse-goto-source)
 115     ;; From XEmacs' diff-mode.
 116     ("W" . widen)
 117     ;;("." . diff-goto-source)          ;display-buffer
 118     ;;("f" . diff-goto-source)          ;find-file
 119     ("o" . diff-goto-source)            ;other-window
 120     ;;("w" . diff-goto-source)          ;other-frame
 121     ;;("N" . diff-narrow)
 122     ;;("h" . diff-show-header)
 123     ;;("j" . diff-show-difference)      ;jump to Nth diff
 124     ;;("q" . diff-quit)
 125     (" " . scroll-up)
 126     ("\177" . scroll-down)
 127     ;; Our very own bindings.
 128     ("A" . diff-ediff-patch)
 129     ("r" . diff-restrict-view)
 130     ("R" . diff-reverse-direction)
 131     ("U" . diff-context->unified)
 132     ("C" . diff-unified->context))
 133   "Basic keymap for `diff-mode', bound to various prefix keys.")
 134
 135 (easy-mmode-defmap diff-mode-map
 136   `(("\e" . ,diff-mode-shared-map)
 137     ;; From compilation-minor-mode.
 138     ("\C-c\C-c" . diff-goto-source)
 139     ;; Misc operations.
 140     ("\C-c\C-a" . diff-apply-hunk)
 141     ("\C-c\C-t" . diff-test-hunk))
 142   "Keymap for `diff-mode'.  See also `diff-mode-shared-map'.")
 143
 144 (easy-menu-define diff-mode-menu diff-mode-map
 145   "Menu for `diff-mode'."
 146   '("Diff"
 147     ["Jump to Source"           diff-goto-source        t]
 148     ["Apply with Ediff"         diff-ediff-patch        t]
 149     ["-----" nil nil]
 150     ["Reverse direction"        diff-reverse-direction  t]
 151     ["Context -> Unified"       diff-context->unified   t]
 152     ["Unified -> Context"       diff-unified->context   t]
 153     ;;["Fixup Headers"          diff-fixup-modifs       (not buffer-read-only)]
 154     ))
 155
 156 (defcustom diff-minor-mode-prefix "\C-c="
 157   "Prefix key for `diff-minor-mode' commands."
 158   :group 'diff-mode
 159   :type '(choice (string "\e") (string "C-c=") string))
 160
 161 (easy-mmode-defmap diff-minor-mode-map
 162   `((,diff-minor-mode-prefix . ,diff-mode-shared-map))
 163   "Keymap for `diff-minor-mode'.  See also `diff-mode-shared-map'.")
 164
 165
 166 ;;;;
 167 ;;;; font-lock support
 168 ;;;;
 169
 170 (defface diff-header-face
 171   '((((class color) (background light))
 172      (:background "grey85"))
 173     (t (:bold t)))
 174   "`diff-mode' face inherited by hunk, file and index header faces."
 175   :group 'diff-mode)
 176 (defvar diff-header-face 'diff-header-face)
 177
 178 (defface diff-file-header-face
 179   '((((class color) (background light))
 180      (:background "grey70" :bold t))
 181     (t (:bold t)))                      ; :height 1.3
 182   "`diff-mode' face used to highlight file header lines."
 183   :group 'diff-mode)
 184 (defvar diff-file-header-face 'diff-file-header-face)
 185
 186 (defface diff-index-face
 187   '((t (:inherit diff-file-header-face)))
 188   "`diff-mode' face used to highlight index header lines."
 189   :group 'diff-mode)
 190 (defvar diff-index-face 'diff-index-face)
 191
 192 (defface diff-hunk-header-face
 193   '((t (:inherit diff-header-face)))
 194   "`diff-mode' face used to highlight hunk header lines."
 195   :group 'diff-mode)
 196 (defvar diff-hunk-header-face 'diff-hunk-header-face)
 197
 198 (defface diff-removed-face
 199   '((t (:inherit diff-changed-face)))
 200   "`diff-mode' face used to highlight removed lines."
 201   :group 'diff-mode)
 202 (defvar diff-removed-face 'diff-removed-face)
 203
 204 (defface diff-added-face
 205   '((t (:inherit diff-changed-face)))
 206   "`diff-mode' face used to highlight added lines."
 207   :group 'diff-mode)
 208 (defvar diff-added-face 'diff-added-face)
 209
 210 (defface diff-changed-face
 211   '((t ()))
 212   "`diff-mode' face used to highlight changed lines."
 213   :group 'diff-mode)
 214 (defvar diff-changed-face 'diff-changed-face)
 215
 216 (defface diff-comment-face
 217   '((t (:inherit font-lock-comment-face)))
 218   "`diff-mode' face used to highlight context and other side-information."
 219   :group 'diff-mode)
 220 (defvar diff-comment-face 'diff-comment-face)
 221
 222 (defvar diff-font-lock-keywords
 223   '(("^\\(@@ -[0-9,]+ \\+[0-9,]+ @@\\)\\(.*\\)$" ;unified
 224      (1 diff-hunk-header-face)
 225      (2 diff-comment-face))
 226     ("^--- .+ ----$"            ;context
 227      . diff-hunk-header-face)
 228     ("\\(\\*\\{15\\}\\)\\(.*\\)$"       ;context
 229      (1 diff-hunk-header-face)
 230      (2 diff-comment-face))
 231     ("^\\*\\*\\* .+ \\*\\*\\*\\*". diff-hunk-header-face) ;context
 232     ("^\\(---\\|\\+\\+\\+\\|\\*\\*\\*\\) \\(\\S-+\\)\\(.*[^*-]\\)?\n"
 233      (0 diff-header-face) (2 diff-file-header-face prepend))
 234     ("^[0-9,]+[acd][0-9,]+$" . diff-hunk-header-face)
 235     ("^!.*\n" . diff-changed-face)      ;context
 236     ("^[+>].*\n" . diff-added-face)
 237     ("^[-<].*\n" . diff-removed-face)
 238     ("^Index: \\(.+\\).*\n" (0 diff-header-face) (1 diff-index-face prepend))
 239     ("^#.*" . font-lock-string-face)
 240     ("^[^-=+*!<>].*\n" . diff-comment-face)))
 241
 242 (defconst diff-font-lock-defaults
 243   '(diff-font-lock-keywords t nil nil nil (font-lock-multiline . nil)))
 244
 245 (defvar diff-imenu-generic-expression
 246   ;; Prefer second name as first is most likely to be a backup or
 247   ;; version-control name.
 248   '((nil "\\+\\+\\+\\ \\([^\t\n]+\\)\t" 1) ; unidiffs
 249     (nil "^--- \\([^\t\n]+\\)\t.*\n\\*" 1))) ; context diffs
 250
 251 ;;;;
 252 ;;;; Compile support
 253 ;;;;
 254
 255 (defvar diff-file-regexp-alist
 256   '(("Index: \\(.+\\)" 1)))
 257
 258 (defvar diff-error-regexp-alist
 259   '(("@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@" nil 2)
 260     ("--- \\([0-9]+\\),[0-9]+ ----" nil 1)
 261     ("\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)" nil 3)))
 262
 263 ;;;;
 264 ;;;; Movement
 265 ;;;;
 266
 267 (defconst diff-hunk-header-re "^\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|\\*\\{15\\}.*\n\\*\\*\\* .+ \\*\\*\\*\\*\\|[0-9]+\\(,[0-9]+\\)?[acd][0-9]+\\(,[0-9]+\\)?\\)$")
 268 (defconst diff-file-header-re (concat "^\\(--- .+\n\\+\\+\\+\\|\\*\\*\\* .+\n---\\|[^-+!<>0-9@* ]\\).+\n" (substring diff-hunk-header-re 1)))
 269 (defvar diff-narrowed-to nil)
 270
 271 (defun diff-end-of-hunk (&optional style)
 272   (if (looking-at diff-hunk-header-re) (goto-char (match-end 0)))
 273   (let ((end (and (re-search-forward (case style
 274                                        (unified "^[^-+# \\]")
 275                                        (context "^[^-+#! \\]")
 276                                        (normal "^[^<>#\\]")
 277                                        (t "^[^-+#!<> \\]"))
 278                                      nil t)
 279                   (match-beginning 0))))
 280     ;; The return value is used by easy-mmode-define-navigation.
 281     (goto-char (or end (point-max)))))
 282
 283 (defun diff-beginning-of-hunk ()
 284   (beginning-of-line)
 285   (unless (looking-at diff-hunk-header-re)
 286     (forward-line 1)
 287     (condition-case ()
 288         (re-search-backward diff-hunk-header-re)
 289       (error (error "Can't find the beginning of the hunk")))))
 290
 291 (defun diff-beginning-of-file ()
 292   (beginning-of-line)
 293   (unless (looking-at diff-file-header-re)
 294     (forward-line 2)
 295     (condition-case ()
 296         (re-search-backward diff-file-header-re)
 297       (error (error "Can't find the beginning of the file")))))
 298
 299 (defun diff-end-of-file ()
 300   (re-search-forward "^[-+#!<>0-9@* \\]" nil t)
 301   (re-search-forward "^[^-+#!<>0-9@* \\]" nil 'move)
 302   (beginning-of-line))
 303
 304 ;; Define diff-{hunk,file}-{prev,next}
 305 (easy-mmode-define-navigation
 306  diff-hunk diff-hunk-header-re "hunk" diff-end-of-hunk)
 307 (easy-mmode-define-navigation
 308  diff-file diff-file-header-re "file" diff-end-of-hunk)
 309
 310 (defun diff-restrict-view (&optional arg)
 311   "Restrict the view to the current hunk.
 312 If the prefix ARG is given, restrict the view to the current file instead."
 313   (interactive "P")
 314   (save-excursion
 315     (if arg (diff-beginning-of-file) (diff-beginning-of-hunk))
 316     (narrow-to-region (point)
 317                       (progn (if arg (diff-end-of-file) (diff-end-of-hunk))
 318                              (point)))
 319     (set (make-local-variable 'diff-narrowed-to) (if arg 'file 'hunk))))
 320
 321
 322 (defun diff-hunk-kill ()
 323   "Kill current hunk."
 324   (interactive)
 325   (diff-beginning-of-hunk)
 326   (let ((start (point))
 327         (firsthunk (save-excursion
 328                      (ignore-errors
 329                        (diff-beginning-of-file) (diff-hunk-next) (point))))
 330         (nexthunk  (save-excursion
 331                      (ignore-errors
 332                        (diff-hunk-next) (point))))
 333         (nextfile (save-excursion
 334                     (ignore-errors
 335                       (diff-file-next) (point)))))
 336     (if (and firsthunk (= firsthunk start)
 337              (or (null nexthunk)
 338                  (and nextfile (> nexthunk nextfile))))
 339         ;; we're the only hunk for this file, so kill the file
 340         (diff-file-kill)
 341       (diff-end-of-hunk)
 342       (kill-region start (point)))))
 343
 344 (defun diff-file-kill ()
 345   "Kill current file's hunks."
 346   (interactive)
 347   (diff-beginning-of-file)
 348   (let* ((start (point))
 349          (prevhunk (save-excursion
 350                      (ignore-errors
 351                        (diff-hunk-prev) (point))))
 352          (index (save-excursion
 353                   (re-search-backward "^Index: " prevhunk t))))
 354     (when index (setq start index))
 355     (diff-end-of-file)
 356     (kill-region start (point))))
 357
 358 (defun diff-kill-junk ()
 359   "Kill spurious empty diffs."
 360   (interactive)
 361   (save-excursion
 362     (let ((inhibit-read-only t))
 363       (goto-char (point-min))
 364       (while (re-search-forward (concat "^\\(Index: .*\n\\)"
 365                                         "\\([^-+!* <>].*\n\\)*?"
 366                                         "\\(\\(Index:\\) \\|"
 367                                         diff-file-header-re "\\)")
 368                                 nil t)
 369         (delete-region (if (match-end 4) (match-beginning 0) (match-end 1))
 370                        (match-beginning 3))
 371         (beginning-of-line)))))
 372
 373 ;;;;
 374 ;;;; jump to other buffers
 375 ;;;;
 376
 377 (defvar diff-remembered-files-alist nil)
 378
 379 (defun diff-filename-drop-dir (file)
 380   (when (string-match "/" file) (substring file (match-end 0))))
 381
 382 (defun diff-merge-strings (ancestor from to)
 383   "Merge the diff between ANCESTOR and FROM into TO.
 384 Returns the merged string if successful or nil otherwise.
 385 The strings are assumed not to contain any \"\\n\" (i.e. end of line).
 386 If ANCESTOR = FROM, returns TO.
 387 If ANCESTOR = TO, returns FROM.
 388 The heuristic is simplistic and only really works for cases
 389 like \(diff-merge-strings \"b/foo\" \"b/bar\" \"/a/c/foo\")."
 390   ;; Ideally, we want:
 391   ;;   AMB ANB CMD -> CND
 392   ;; but that's ambiguous if `foo' or `bar' is empty:
 393   ;; a/foo a/foo1 b/foo.c -> b/foo1.c but not 1b/foo.c or b/foo.c1
 394   (let ((str (concat ancestor "\n" from "\n" to)))
 395     (when (and (string-match (concat
 396                               "\\`\\(.*?\\)\\(.*\\)\\(.*\\)\n"
 397                               "\\1\\(.*\\)\\3\n"
 398                               "\\(.*\\(\\2\\).*\\)\\'") str)
 399                (equal to (match-string 5 str)))
 400       (concat (substring str (match-beginning 5) (match-beginning 6))
 401               (match-string 4 str)
 402               (substring str (match-end 6) (match-end 5))))))
 403
 404 (defun diff-find-file-name (&optional old)
 405   "Return the file corresponding to the current patch.
 406 Non-nil OLD means that we want the old file."
 407   (save-excursion
 408     (unless (looking-at diff-file-header-re)
 409       (or (ignore-errors (diff-beginning-of-file))
 410           (re-search-forward diff-file-header-re nil t)))
 411     (let* ((limit (save-excursion
 412                    (condition-case ()
 413                        (progn (diff-hunk-prev) (point))
 414                      (error (point-min)))))
 415            (header-files
 416             (if (looking-at "[-*][-*][-*] \\(\\S-+\\)\\s-.*\n[-+][-+][-+] \\(\\S-+\\)\\s-.*$")
 417                 (list (if old (match-string 1) (match-string 2))
 418                       (if old (match-string 2) (match-string 1)))
 419               (forward-line 1) nil))
 420            (fs (append
 421                 (when (save-excursion
 422                         (re-search-backward "^Index: \\(.+\\)" limit t))
 423                   (list (match-string 1)))
 424                 header-files
 425                 (when (re-search-backward "^diff \\(-\\S-+ +\\)*\\(\\S-+\\)\\( +\\(\\S-+\\)\\)?" nil t)
 426                   (list (if old (match-string 2) (match-string 4))
 427                         (if old (match-string 4) (match-string 2))))))
 428            (fs (delq nil fs)))
 429       (or
 430        ;; use any previously used preference
 431        (cdr (assoc fs diff-remembered-files-alist))
 432        ;; try to be clever and use previous choices as an inspiration
 433        (dolist (rf diff-remembered-files-alist)
 434          (let ((newfile (diff-merge-strings (caar rf) (car fs) (cdr rf))))
 435            (if (and newfile (file-exists-p newfile)) (return newfile))))
 436        ;; look for each file in turn.  If none found, try again but
 437        ;; ignoring the first level of directory, ...
 438        (do* ((files fs (delq nil (mapcar 'diff-filename-drop-dir files)))
 439              (file nil nil))
 440            ((or (null files)
 441                 (setq file (do* ((files files (cdr files))
 442                                  (file (car files) (car files)))
 443                                ((or (null file) (file-exists-p file))
 444                                 file))))
 445             file))
 446        ;; <foo>.rej patches implicitly apply to <foo>
 447        (and (string-match "\\.rej\\'" (or buffer-file-name ""))
 448             (let ((file (substring buffer-file-name 0 (match-beginning 0))))
 449               (when (file-exists-p file) file)))
 450        ;; if all else fails, ask the user
 451        (let ((file (read-file-name (format "Use file %s: " (or (first fs) ""))
 452                                    nil (first fs) t (first fs))))
 453          (set (make-local-variable 'diff-remembered-files-alist)
 454               (cons (cons fs file) diff-remembered-files-alist))
 455          file)))))
 456
 457
 458 (defun diff-mouse-goto-source (event)
 459   "Run `diff-goto-source' for the diff at a mouse click."
 460   (interactive "e")
 461   (save-excursion
 462     (mouse-set-point event)
 463     (diff-goto-source)))
 464
 465
 466 (defun diff-ediff-patch ()
 467   "Call `ediff-patch-file' on the current buffer."
 468   (interactive)
 469   (condition-case err
 470       (ediff-patch-file nil (current-buffer))
 471     (wrong-number-of-arguments (ediff-patch-file))))
 472
 473 ;;;;
 474 ;;;; Conversion functions
 475 ;;;;
 476
 477 ;;(defvar diff-inhibit-after-change nil
 478 ;;  "Non-nil means inhibit `diff-mode's after-change functions.")
 479
 480 (defun diff-unified->context (start end)
 481   "Convert unified diffs to context diffs.
 482 START and END are either taken from the region (if a prefix arg is given) or
 483 else cover the whole bufer."
 484   (interactive (if current-prefix-arg
 485                    (list (mark) (point))
 486                  (list (point-min) (point-max))))
 487   (unless (markerp end) (setq end (copy-marker end)))
 488   (let (;;(diff-inhibit-after-change t)
 489         (inhibit-read-only t))
 490     (save-excursion
 491       (goto-char start)
 492       (while (and (re-search-forward "^\\(\\(---\\) .+\n\\(\\+\\+\\+\\) .+\\|@@ -\\([0-9]+\\),\\([0-9]+\\) \\+\\([0-9]+\\),\\([0-9]+\\) @@.*\\)$" nil t)
 493                   (< (point) end))
 494         (combine-after-change-calls
 495           (if (match-beginning 2)
 496               ;; we matched a file header
 497               (progn
 498                 ;; use reverse order to make sure the indices are kept valid
 499                 (replace-match "---" t t nil 3)
 500                 (replace-match "***" t t nil 2))
 501             ;; we matched a hunk header
 502             (let ((line1 (match-string 4))
 503                   (lines1 (match-string 5))
 504                   (line2 (match-string 6))
 505                   (lines2 (match-string 7)))
 506               (replace-match
 507                (concat "***************\n*** " line1 ","
 508                        (number-to-string (+ (string-to-number line1)
 509                                             (string-to-number lines1)
 510                                             -1)) " ****"))
 511               (forward-line 1)
 512               (save-restriction
 513                 (narrow-to-region (point)
 514                                   (progn (diff-end-of-hunk 'unified) (point)))
 515                 (let ((hunk (buffer-string)))
 516                   (goto-char (point-min))
 517                   (if (not (save-excursion (re-search-forward "^-" nil t)))
 518                       (delete-region (point) (point-max))
 519                     (goto-char (point-max))
 520                     (let ((modif nil) last-pt)
 521                       (while (progn (setq last-pt (point))
 522                                     (= (forward-line -1) 0))
 523                         (case (char-after)
 524                           (?  (insert " ") (setq modif nil) (backward-char 1))
 525                           (?+ (delete-region (point) last-pt) (setq modif t))
 526                           (?- (if (not modif)
 527                                   (progn (forward-char 1)
 528                                          (insert " "))
 529                                 (delete-char 1)
 530                                 (insert "! "))
 531                               (backward-char 2))
 532                           (?\\ (when (save-excursion (forward-line -1)
 533                                                      (= (char-after) ?+))
 534                                  (delete-region (point) last-pt) (setq modif t)))
 535                           (t (setq modif nil))))))
 536                   (goto-char (point-max))
 537                   (save-excursion
 538                     (insert "--- " line2 ","
 539                             (number-to-string (+ (string-to-number line2)
 540                                                  (string-to-number lines2)
 541                                                  -1)) " ----\n" hunk))
 542                   ;;(goto-char (point-min))
 543                   (forward-line 1)
 544                   (if (not (save-excursion (re-search-forward "^+" nil t)))
 545                       (delete-region (point) (point-max))
 546                     (let ((modif nil) (delete nil))
 547                       (while (not (eobp))
 548                         (case (char-after)
 549                           (?  (insert " ") (setq modif nil) (backward-char 1))
 550                           (?- (setq delete t) (setq modif t))
 551                           (?+ (if (not modif)
 552                                   (progn (forward-char 1)
 553                                          (insert " "))
 554                                 (delete-char 1)
 555                                 (insert "! "))
 556                               (backward-char 2))
 557                           (?\\ (when (save-excursion (forward-line 1)
 558                                                      (not (eobp)))
 559                                  (setq delete t) (setq modif t)))
 560                           (t (setq modif nil)))
 561                         (let ((last-pt (point)))
 562                           (forward-line 1)
 563                           (when delete
 564                             (delete-region last-pt (point))
 565                             (setq delete nil)))))))))))))))
 566
 567 (defun diff-context->unified (start end)
 568   "Convert context diffs to unified diffs.
 569 START and END are either taken from the region (if a prefix arg is given) or
 570 else cover the whole bufer."
 571   (interactive (if current-prefix-arg
 572                    (list (mark) (point))
 573                  (list (point-min) (point-max))))
 574   (unless (markerp end) (setq end (copy-marker end)))
 575   (let (;;(diff-inhibit-after-change t)
 576         (inhibit-read-only t))
 577     (save-excursion
 578       (goto-char start)
 579       (while (and (re-search-forward "^\\(\\(\\*\\*\\*\\) .+\n\\(---\\) .+\\|\\*\\{15\\}.*\n\\*\\*\\* \\([0-9]+\\),\\(-?[0-9]+\\) \\*\\*\\*\\*\\)$" nil t)
 580                   (< (point) end))
 581         (combine-after-change-calls
 582           (if (match-beginning 2)
 583               ;; we matched a file header
 584               (progn
 585                 ;; use reverse order to make sure the indices are kept valid
 586                 (replace-match "+++" t t nil 3)
 587                 (replace-match "---" t t nil 2))
 588             ;; we matched a hunk header
 589             (let ((line1s (match-string 4))
 590                   (line1e (match-string 5))
 591                   (pt1 (match-beginning 0)))
 592               (replace-match "")
 593               (unless (re-search-forward
 594                        "^--- \\([0-9]+\\),\\(-?[0-9]+\\) ----$" nil t)
 595                 (error "Can't find matching `--- n1,n2 ----' line"))
 596               (let ((line2s (match-string 1))
 597                     (line2e (match-string 2))
 598                     (pt2 (progn
 599                            (delete-region (progn (beginning-of-line) (point))
 600                                           (progn (forward-line 1) (point)))
 601                            (point-marker))))
 602                 (goto-char pt1)
 603                 (forward-line 1)
 604                 (while (< (point) pt2)
 605                   (case (char-after)
 606                     ((?! ?-) (delete-char 2) (insert "-") (forward-line 1))
 607                     (?\                 ;merge with the other half of the chunk
 608                      (let* ((endline2
 609                              (save-excursion
 610                                (goto-char pt2) (forward-line 1) (point)))
 611                             (c (char-after pt2)))
 612                        (case c
 613                          ((?! ?+)
 614                           (insert "+"
 615                                   (prog1 (buffer-substring (+ pt2 2) endline2)
 616                                     (delete-region pt2 endline2))))
 617                          (?\            ;FIXME: check consistency
 618                           (delete-region pt2 endline2)
 619                           (delete-char 1)
 620                           (forward-line 1))
 621                          (?\\ (forward-line 1))
 622                          (t (delete-char 1) (forward-line 1)))))
 623                     (t (forward-line 1))))
 624                 (while (looking-at "[+! ] ")
 625                   (if (/= (char-after) ?!) (forward-char 1)
 626                     (delete-char 1) (insert "+"))
 627                   (delete-char 1) (forward-line 1))
 628                 (save-excursion
 629                   (goto-char pt1)
 630                   (insert "@@ -" line1s ","
 631                           (number-to-string (- (string-to-number line1e)
 632                                                (string-to-number line1s)
 633                                                -1))
 634                           " +" line2s ","
 635                           (number-to-string (- (string-to-number line2e)
 636                                                (string-to-number line2s)
 637                                                -1)) " @@"))))))))))
 638
 639 (defun diff-reverse-direction (start end)
 640   "Reverse the direction of the diffs.
 641 START and END are either taken from the region (if a prefix arg is given) or
 642 else cover the whole bufer."
 643   (interactive (if current-prefix-arg
 644                    (list (mark) (point))
 645                  (list (point-min) (point-max))))
 646   (unless (markerp end) (setq end (copy-marker end)))
 647   (let (;;(diff-inhibit-after-change t)
 648         (inhibit-read-only t))
 649     (save-excursion
 650       (goto-char start)
 651       (while (and (re-search-forward "^\\(\\([-*][-*][-*] \\)\\(.+\\)\n\\([-+][-+][-+] \\)\\(.+\\)\\|\\*\\{15\\}.*\n\\*\\*\\* \\(.+\\) \\*\\*\\*\\*\\|@@ -\\([0-9,]+\\) \\+\\([0-9,]+\\) @@.*\\)$" nil t)
 652                   (< (point) end))
 653         (combine-after-change-calls
 654           (cond
 655            ;; a file header
 656            ((match-beginning 2) (replace-match "\\2\\5\n\\4\\3" nil))
 657            ;; a context-diff hunk header
 658            ((match-beginning 6)
 659             (let ((pt-lines1 (match-beginning 6))
 660                   (lines1 (match-string 6)))
 661               (replace-match "" nil nil nil 6)
 662               (forward-line 1)
 663               (let ((half1s (point)))
 664                 (while (looking-at "[-! \\][ \t]\\|#")
 665                   (when (= (char-after) ?-) (delete-char 1) (insert "+"))
 666                   (forward-line 1))
 667                 (let ((half1 (delete-and-extract-region half1s (point))))
 668                   (unless (looking-at "^--- \\([0-9]+,-?[0-9]+\\) ----$")
 669                     (insert half1)
 670                     (error "Can't find matching `--- n1,n2 ----' line"))
 671                   (let ((str1 (match-string 1)))
 672                     (replace-match lines1 nil nil nil 1)
 673                     (forward-line 1)
 674                     (let ((half2s (point)))
 675                       (while (looking-at "[!+ \\][ \t]\\|#")
 676                         (when (= (char-after) ?+) (delete-char 1) (insert "-"))
 677                         (forward-line 1))
 678                       (let ((half2 (delete-and-extract-region half2s (point))))
 679                         (insert (or half1 ""))
 680                         (goto-char half1s)
 681                         (insert (or half2 ""))))
 682                     (goto-char pt-lines1)
 683                     (insert str1))))))
 684            ;; a unified-diff hunk header
 685            ((match-beginning 7)
 686             (replace-match "@@ -\\8 +\\7 @@" nil)
 687             (forward-line 1)
 688             (let ((c (char-after)) first last)
 689               (while (case (setq c (char-after))
 690                        (?- (setq first (or first (point)))
 691                            (delete-char 1) (insert "+") t)
 692                        (?+ (setq last (or last (point)))
 693                            (delete-char 1) (insert "-") t)
 694                        ((?\\ ?#) t)
 695                        (t (when (and first last (< first last))
 696                             (let ((str
 697                                    (save-excursion
 698                                      (delete-and-extract-region first last))))
 699                               (insert str)))
 700                           (setq first nil last nil)
 701                           (equal ?\  c)))
 702                 (forward-line 1))))))))))
 703
 704 (defun diff-fixup-modifs (start end)
 705   "Fixup the hunk headers (in case the buffer was modified).
 706 START and END are either taken from the region (if a prefix arg is given) or
 707 else cover the whole bufer."
 708   (interactive (if current-prefix-arg
 709                    (list (mark) (point))
 710                  (list (point-min) (point-max))))
 711   (let ((inhibit-read-only t))
 712     (save-excursion
 713       (goto-char end) (diff-end-of-hunk)
 714       (let ((plus 0) (minus 0) (space 0) (bang 0))
 715         (while (and (= (forward-line -1) 0) (<= start (point)))
 716           (if (not (looking-at "\\(@@ -[0-9,]+ \\+[0-9,]+ @@.*\\|[-*][-*][-*] .+ [-*][-*][-*][-*]\\)$"))
 717               (case (char-after)
 718                 (?\  (incf space))
 719                 (?+ (incf plus))
 720                 (?- (incf minus))
 721                 (?! (incf bang))
 722                 ((?\\ ?#) nil)
 723                 (t  (setq space 0 plus 0 minus 0 bang 0)))
 724             (cond
 725              ((looking-at "@@ -[0-9]+,\\([0-9]*\\) \\+[0-9]+,\\([0-9]*\\) @@.*$")
 726               (let* ((old1 (match-string 1))
 727                      (old2 (match-string 2))
 728                      (new1 (number-to-string (+ space minus)))
 729                      (new2 (number-to-string (+ space plus))))
 730                 (unless (string= new2 old2) (replace-match new2 t t nil 2))
 731                 (unless (string= new1 old1) (replace-match new1 t t nil 1))))
 732              ((looking-at "--- \\([0-9]+\\),\\([0-9]*\\) ----$")
 733               (when (> (+ space bang plus) 0)
 734                 (let* ((old1 (match-string 1))
 735                        (old2 (match-string 2))
 736                        (new (number-to-string
 737                              (+ space bang plus -1 (string-to-number old1)))))
 738                   (unless (string= new old2) (replace-match new t t nil 2)))))
 739              ((looking-at "\\*\\*\\* \\([0-9]+\\),\\(-?[0-9]*\\) \\*\\*\\*\\*$")
 740               (when (> (+ space bang minus) 0)
 741                 (let* ((old (match-string 1))
 742                        (new (format
 743                              (concat "%0" (number-to-string (length old)) "d")
 744                              (+ space bang minus -1 (string-to-number old)))))
 745                   (unless (string= new old) (replace-match new t t nil 2))))))
 746             (setq space 0 plus 0 minus 0 bang 0)))))))
 747
 748 ;;;;
 749 ;;;; Hooks
 750 ;;;;
 751
 752 (defun diff-write-contents-hooks ()
 753   "Fixup hunk headers if necessary."
 754   (if (buffer-modified-p) (diff-fixup-modifs (point-min) (point-max)))
 755   nil)
 756
 757 ;; It turns out that making changes in the buffer from within an
 758 ;; *-change-function is asking for trouble, whereas making them
 759 ;; from a post-command-hook doesn't pose much problems
 760 (defvar diff-unhandled-changes nil)
 761 (defun diff-after-change-function (beg end len)
 762   "Remember to fixup the hunk header.
 763 See `after-change-functions' for the meaning of BEG, END and LEN."
 764   ;; Ignoring changes when inhibit-read-only is set is strictly speaking
 765   ;; incorrect, but it turns out that inhibit-read-only is normally not set
 766   ;; inside editing commands, while it tends to be set when the buffer gets
 767   ;; updated by an async process or by a conversion function, both of which
 768   ;; would rather not be uselessly slowed down by this hook.
 769   (when (and (not undo-in-progress) (not inhibit-read-only))
 770     (if diff-unhandled-changes
 771         (setq diff-unhandled-changes
 772               (cons (min beg (car diff-unhandled-changes))
 773                     (max beg (cdr diff-unhandled-changes))))
 774       (setq diff-unhandled-changes (cons beg end)))))
 775
 776 (defun diff-post-command-hook ()
 777   "Fixup hunk headers if necessary."
 778   (when (consp diff-unhandled-changes)
 779     (ignore-errors
 780       (save-excursion
 781         (goto-char (car diff-unhandled-changes))
 782         (unless (ignore-errors
 783                   (diff-beginning-of-hunk)
 784                   (save-excursion
 785                     (diff-end-of-hunk)
 786                     (> (point) (car diff-unhandled-changes))))
 787           (goto-char (car diff-unhandled-changes))
 788           (re-search-forward diff-hunk-header-re (cdr diff-unhandled-changes))
 789           (diff-beginning-of-hunk))
 790         (diff-fixup-modifs (point) (cdr diff-unhandled-changes))))
 791     (setq diff-unhandled-changes nil)))
 792
 793 ;;;;
 794 ;;;; The main function
 795 ;;;;
 796
 797 ;;;###autoload
 798 (define-derived-mode diff-mode fundamental-mode "Diff"
 799   "Major mode for viewing/editing context diffs.
 800 Supports unified and context diffs as well as (to a lesser extent) normal diffs.
 801 When the buffer is read-only, the ESC prefix is not necessary.
 802 This mode runs `diff-mode-hook'.
 803 \\{diff-mode-map}"
 804   (set (make-local-variable 'font-lock-defaults) diff-font-lock-defaults)
 805   (set (make-local-variable 'outline-regexp) diff-outline-regexp)
 806   (set (make-local-variable 'imenu-generic-expression)
 807        diff-imenu-generic-expression)
 808   ;; These are not perfect.  They would be better done separately for
 809   ;; context diffs and unidiffs.
 810   ;; (set (make-local-variable 'paragraph-start)
 811   ;;        (concat "@@ "                       ; unidiff hunk
 812   ;;           "\\|\\*\\*\\* "          ; context diff hunk or file start
 813   ;;           "\\|--- [^\t]+\t"))      ; context or unidiff file
 814   ;;                                    ; start (first or second line)
 815   ;;   (set (make-local-variable 'paragraph-separate) paragraph-start)
 816   ;;   (set (make-local-variable 'page-delimiter) "--- [^\t]+\t")
 817   ;; compile support
 818   (set (make-local-variable 'compilation-file-regexp-alist)
 819        diff-file-regexp-alist)
 820   (set (make-local-variable 'compilation-error-regexp-alist)
 821        diff-error-regexp-alist)
 822   (when (string-match "\\.rej\\'" (or buffer-file-name ""))
 823     (set (make-local-variable 'compilation-current-file)
 824          (substring buffer-file-name 0 (match-beginning 0))))
 825   (compilation-shell-minor-mode 1)
 826   ;; setup change hooks
 827   (toggle-read-only t)
 828   (if (not diff-update-on-the-fly-flag)
 829       (add-hook 'write-contents-hooks 'diff-write-contents-hooks)
 830     (make-local-variable 'diff-unhandled-changes)
 831     (add-hook 'after-change-functions 'diff-after-change-function nil t)
 832     (add-hook 'post-command-hook 'diff-post-command-hook nil t))
 833   ;; Neat trick from Dave Love to add more bindings in read-only mode:
 834   (add-to-list (make-local-variable 'minor-mode-overriding-map-alist)
 835                (cons 'buffer-read-only diff-mode-shared-map))
 836   ;; add-log support
 837   (set (make-local-variable 'add-log-current-defun-function)
 838        'diff-current-defun)
 839   (set (make-local-variable 'add-log-buffer-file-name-function)
 840        'diff-find-file-name))
 841
 842 ;;;###autoload
 843 (define-minor-mode diff-minor-mode
 844   "Minor mode for viewing/editing context diffs.
 845 \\{diff-minor-mode-map}"
 846   nil " Diff" nil
 847   ;; FIXME: setup font-lock
 848   ;; setup change hooks
 849   (if (not diff-update-on-the-fly-flag)
 850       (add-hook 'write-contents-hooks 'diff-write-contents-hooks)
 851     (make-local-variable 'diff-unhandled-changes)
 852     (add-hook 'after-change-functions 'diff-after-change-function nil t)
 853     (add-hook 'post-command-hook 'diff-post-command-hook nil t)))
 854
 855
 856 ;;;
 857 ;;; Misc operations that have proved useful at some point.
 858 ;;;
 859
 860 (defun diff-next-complex-hunk ()
 861   "Jump to the next \"complex\" hunk.
 862 \"Complex\" is approximated by \"the hunk changes the number of lines\".
 863 Only works for unified diffs."
 864   (interactive)
 865   (while
 866       (and (re-search-forward "^@@ [-0-9]+,\\([0-9]+\\) [+0-9]+,\\([0-9]+\\) @@"
 867                               nil t)
 868            (equal (match-string 1) (match-string 2)))))
 869
 870 (defun diff-hunk-text (hunk destp &optional char-offset)
 871   "Return the literal source text from HUNK.
 872 if DESTP is nil return the source, otherwise the destination text.
 873 If CHAR-OFFSET is non-nil, it should be a char-offset in
 874 HUNK, and instead of a string, a cons cell is returned whose car is the
 875 appropriate text, and whose cdr is the corresponding char-offset in that text."
 876   (with-temp-buffer
 877     (insert hunk)
 878     (goto-char (point-min))
 879     (let ((src-pos nil)
 880           (dst-pos nil)
 881           (divider-pos nil)
 882           (num-pfx-chars 2))
 883       ;; Set the following variables:
 884       ;;  SRC-POS     buffer pos of the source part of the hunk or nil if none
 885       ;;  DST-POS     buffer pos of the destination part of the hunk or nil
 886       ;;  DIVIDER-POS buffer pos of any divider line separating the src & dst
 887       ;;  NUM-PFX-CHARS  number of line-prefix characters used by this format"
 888       (cond ((looking-at "^@@")
 889              ;; unified diff
 890              (setq num-pfx-chars 1)
 891              (forward-line 1)
 892              (setq src-pos (point) dst-pos (point)))
 893             ((looking-at "^\\*\\*")
 894              ;; context diff
 895              (forward-line 2)
 896              (setq src-pos (point))
 897              (re-search-forward "^--- " nil t)
 898              (forward-line 0)
 899              (setq divider-pos (point))
 900              (forward-line 1)
 901              (setq dst-pos (point)))
 902             ((looking-at "^[0-9]+a[0-9,]+$")
 903              ;; normal diff, insert
 904              (forward-line 1)
 905              (setq dst-pos (point)))
 906             ((looking-at "^[0-9,]+d[0-9]+$")
 907              ;; normal diff, delete
 908              (forward-line 1)
 909              (setq src-pos (point)))
 910             ((looking-at "^[0-9,]+c[0-9,]+$")
 911              ;; normal diff, change
 912              (forward-line 1)
 913              (setq src-pos (point))
 914              (re-search-forward "^---$" nil t)
 915              (forward-line 0)
 916              (setq divider-pos (point))
 917              (forward-line 1)
 918              (setq dst-pos (point)))
 919             (t
 920              (error "Unknown diff hunk type")))
 921
 922       (if (if destp (null dst-pos) (null src-pos))
 923           ;; Implied empty text
 924           (if char-offset '("" . 0) "")
 925
 926         ;; For context diffs, either side can be empty, (if there's only
 927         ;; added or only removed text).  We should then use the other side.
 928         (cond ((equal src-pos divider-pos) (setq src-pos dst-pos))
 929               ((equal dst-pos (point-max)) (setq dst-pos src-pos)))
 930
 931         (when char-offset (goto-char (+ (point-min) char-offset)))
 932
 933         ;; Get rid of anything except the desired text.
 934         (save-excursion
 935           ;; Delete unused text region
 936           (let ((keep (if destp dst-pos src-pos)))
 937             (when (and divider-pos (> divider-pos keep))
 938               (delete-region divider-pos (point-max)))
 939             (delete-region (point-min) keep))
 940           ;; Remove line-prefix characters, and unneeded lines (unified diffs).
 941           (let ((kill-char (if destp ?- ?+)))
 942             (goto-char (point-min))
 943             (while (not (eobp))
 944               (if (eq (char-after) kill-char)
 945                   (delete-region (point) (progn (forward-line 1) (point)))
 946                 (delete-char num-pfx-chars)
 947                 (forward-line 1)))))
 948
 949         (let ((text (buffer-substring-no-properties (point-min) (point-max))))
 950           (if char-offset (cons text (- (point) (point-min))) text))))))
 951
 952
 953 (defun diff-find-text (text)
 954   "Return the buffer position of the nearest occurrence of TEXT.
 955 If TEXT isn't found, nil is returned."
 956   (let* ((orig (point))
 957          (forw (and (search-forward text nil t)
 958                           (match-beginning 0)))
 959          (back (and (goto-char (+ orig (length text)))
 960                     (search-backward text nil t)
 961                           (match-beginning 0))))
 962           ;; Choose the closest match.
 963     (if (and forw back)
 964         (if (> (- forw orig) (- orig back)) back forw)
 965       (or back forw))))
 966
 967 (defsubst diff-xor (a b) (if a (not b) b))
 968
 969 (defun diff-find-source-location (&optional other-file reverse)
 970   "Find out (BUF LINE-OFFSET POS SRC DST SWITCHED)."
 971   (save-excursion
 972     (let* ((other (diff-xor other-file diff-jump-to-old-file-flag))
 973            (char-offset (- (point) (progn (diff-beginning-of-hunk) (point))))
 974            (hunk (buffer-substring (point)
 975                                    (save-excursion (diff-end-of-hunk) (point))))
 976            (old (diff-hunk-text hunk reverse char-offset))
 977            (new (diff-hunk-text hunk (not reverse) char-offset))
 978            ;; Find the location specification.
 979            (line (if (not (looking-at "\\(?:\\*\\{15\\}.*\n\\)?[-@* ]*\\([0-9,]+\\)\\([ acd+]+\\([0-9,]+\\)\\)?"))
 980                      (error "Can't find the hunk header")
 981                    (if other (match-string 1)
 982                      (if (match-end 3) (match-string 3)
 983                        (unless (re-search-forward "^--- \\([0-9,]+\\)" nil t)
 984                          (error "Can't find the hunk separator"))
 985                        (match-string 1)))))
 986            (file (or (diff-find-file-name other) (error "Can't find the file")))
 987            (buf (find-file-noselect file)))
 988       ;; Update the user preference if he so wished.
 989       (when (> (prefix-numeric-value other-file) 8)
 990         (setq diff-jump-to-old-file-flag other))
 991       (with-current-buffer buf
 992         (goto-line (string-to-number line))
 993         (let* ((orig-pos (point))
 994                (pos (diff-find-text (car old)))
 995                (switched nil))
 996           (when (null pos)
 997             (setq pos (diff-find-text (car new)) switched t))
 998           (nconc
 999            (list buf)
1000            (if pos (list (count-lines orig-pos pos) pos) (list nil orig-pos))
1001            (if switched (list new old t) (list old new))))))))
1002
1003
1004 (defun diff-hunk-status-msg (line-offset reversed dry-run)
1005   (let ((msg (if dry-run
1006                  (if reversed "already applied" "not yet applied")
1007                (if reversed "undone" "applied"))))
1008     (message (cond ((null line-offset) "Hunk text not found")
1009                    ((= line-offset 0) "Hunk %s")
1010                    ((= line-offset 1) "Hunk %s at offset %d line")
1011                    (t "Hunk %s at offset %d lines"))
1012              msg line-offset)))
1013
1014
1015 (defun diff-apply-hunk (&optional reverse)
1016   "Apply the current hunk to the source file and go to the next.
1017 By default, the new source file is patched, but if the variable
1018 `diff-jump-to-old-file-flag' is non-nil, then the old source file is
1019 patched instead (some commands, such as `diff-goto-source' can change
1020 the value of this variable when given an appropriate prefix argument).
1021
1022 With a prefix argument, REVERSE the hunk."
1023   (interactive "P")
1024   (destructuring-bind (buf line-offset pos old new &optional switched)
1025       (diff-find-source-location nil reverse)
1026     (cond
1027      ((null line-offset)
1028       (error "Can't find the text to patch"))
1029      ((and switched
1030            ;; A reversed patch was detected, perhaps apply it in reverse
1031            (not (save-window-excursion
1032                   (pop-to-buffer buf)
1033                   (goto-char (+ pos (cdr old)))
1034                   (y-or-n-p
1035                    (if reverse
1036                        "Hunk hasn't been applied yet; apply it now? "
1037                      "Hunk has already been applied; undo it? ")))))
1038       (message "(Nothing done)"))
1039      (t
1040       ;; Apply the hunk
1041       (with-current-buffer buf
1042         (goto-char pos)
1043         (delete-char (length (car old)))
1044         (insert (car new)))
1045       ;; Display BUF in a window
1046       (set-window-point (display-buffer buf) (+ pos (cdr new)))
1047       (diff-hunk-status-msg line-offset (diff-xor switched reverse) nil)
1048       (when diff-advance-after-apply-hunk
1049         (diff-hunk-next))))))
1050
1051
1052 (defun diff-test-hunk (&optional reverse)
1053   "See whether it's possible to apply the current hunk.
1054 With a prefix argument, try to REVERSE the hunk."
1055   (interactive "P")
1056   (destructuring-bind (buf line-offset pos src dst &optional switched)
1057       (diff-find-source-location nil reverse)
1058     (set-window-point (display-buffer buf) (+ pos (cdr src)))
1059     (diff-hunk-status-msg line-offset (diff-xor reverse switched) t)))
1060
1061
1062 (defun diff-goto-source (&optional other-file)
1063   "Jump to the corresponding source line.
1064 `diff-jump-to-old-file-flag' (or its opposite if the OTHER-FILE prefix arg
1065 is given) determines whether to jump to the old or the new file.
1066 If the prefix arg is bigger than 8 (for example with \\[universal-argument] \\[universal-argument])
1067   then `diff-jump-to-old-file-flag' is also set, for the next invocations."
1068   (interactive "P")
1069   ;; When pointing at a removal line, we probably want to jump to
1070   ;; the old location, and else to the new (i.e. as if reverting).
1071   ;; This is a convenient detail when using smerge-diff.
1072   (let ((rev (not (save-excursion (beginning-of-line) (looking-at "[-<]")))))
1073     (destructuring-bind (buf line-offset pos src dst &optional switched)
1074         (diff-find-source-location other-file rev)
1075       (pop-to-buffer buf)
1076       (goto-char (+ pos (cdr src)))
1077       (diff-hunk-status-msg line-offset (not switched) t))))
1078
1079
1080 (defun diff-current-defun ()
1081   "Find the name of function at point.
1082 For use in `add-log-current-defun-function'."
1083   (destructuring-bind (buf line-offset pos src dst &optional switched)
1084       (diff-find-source-location)
1085     (save-excursion
1086       (beginning-of-line)
1087       (or (when (memq (char-after) '(?< ?-))
1088             ;; Cursor is pointing at removed text.  This could be a removed
1089             ;; function, in which case, going to the source buffer will
1090             ;; not help since the function is now removed.  Instead,
1091             ;; try to figure out the function name just from the code-fragment.
1092             (let ((old (if switched dst src)))
1093               (with-temp-buffer
1094                 (insert (car old))
1095                 (goto-char (cdr old))
1096                 (funcall (with-current-buffer buf major-mode))
1097                 (add-log-current-defun))))
1098           (with-current-buffer buf
1099             (goto-char (+ pos (cdr src)))
1100             (add-log-current-defun))))))
1101
1102 ;; provide the package
1103 (provide 'diff-mode)
1104
1105 ;;; Old Change Log from when diff-mode wasn't part of Emacs:
1106 ;; Revision 1.11  1999/10/09 23:38:29  monnier
1107 ;; (diff-mode-load-hook): dropped.
1108 ;; (auto-mode-alist): also catch *.diffs.
1109 ;; (diff-find-file-name, diff-mode):  add smarts to find the right file
1110 ;;     for *.rej files (that lack any file name indication).
1111 ;;
1112 ;; Revision 1.10  1999/09/30 15:32:11  monnier
1113 ;; added support for "\ No newline at end of file".
1114 ;;
1115 ;; Revision 1.9  1999/09/15 00:01:13  monnier
1116 ;; - added basic `compile' support.
1117 ;; - have diff-kill-hunk call diff-kill-file if it's the only hunk.
1118 ;; - diff-kill-file now tries to kill the leading garbage as well.
1119 ;;
1120 ;; Revision 1.8  1999/09/13 21:10:09  monnier
1121 ;; - don't use CL in the autoloaded code
1122 ;; - accept diffs using -T
1123 ;;
1124 ;; Revision 1.7  1999/09/05 20:53:03  monnier
1125 ;; interface to ediff-patch
1126 ;;
1127 ;; Revision 1.6  1999/09/01 20:55:13  monnier
1128 ;; (ediff=patch-file):  add bindings to call ediff-patch.
1129 ;; (diff-find-file-name):  taken out of diff-goto-source.
1130 ;; (diff-unified->context, diff-context->unified, diff-reverse-direction,
1131 ;;  diff-fixup-modifs):  only use the region if a prefix arg is given.
1132 ;;
1133 ;; Revision 1.5  1999/08/31 19:18:52  monnier
1134 ;; (diff-beginning-of-file, diff-prev-file):  fixed wrong parenthesis.
1135 ;;
1136 ;; Revision 1.4  1999/08/31 13:01:44  monnier
1137 ;; use `combine-after-change-calls' to minimize the slowdown of font-lock.
1138 ;;
1139
1140 ;;; diff-mode.el ends here