lisp/diff.el

   1 ;;; diff.el --- "DIFF" mode for handling output from unix diff utility.
   2
   3 ;; Copyright (C) 1990 Free Software Foundation, Inc.
   4 ;; Written fpb@ittc.wec.com 1/27/89
   5
   6 ;; This file is part of GNU Emacs.
   7
   8 ;; GNU Emacs is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 1, or (at your option)
  11 ;; any later version.
  12
  13 ;; GNU Emacs is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  20 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22 ;; todo: diff-switches flexibility:
  23 ;; (defconst diff-switches-function
  24 ;;   '(lambda (file)
  25 ;;     (if (string-match "\\.el$" file)
  26 ;;       "-c -F\"^(\""
  27 ;;       "-p"))
  28 ;;  "Function to return switches to pass to the `diff' utility, in \\[diff].
  29 ;; This function is called with one arg, a file name, and returns a string
  30 ;; containing 0 or more arguments which are passed on to `diff'.
  31 ;; NOTE: This is not an ordinary hook; it may not be a list of functions.")
  32
  33 ;;  - fpb@ittc.wec.com - Sep 25, 1990
  34 ;; Added code to support sccs diffing.
  35 ;; also fixed one minor glitch in the
  36 ;; search for the pattern.  If you only 1 addition you won't find the end
  37 ;; of the pattern (minor)
  38
  39 ;;
  40 (defvar diff-switches nil
  41   "*A list of switches to pass to the diff program.")
  42
  43 (defvar diff-search-pattern "^\\([0-9]\\|\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\)"
  44   "Regular expression that delineates difference regions in diffs.")
  45
  46 (defvar diff-rcs-extension ",v"
  47   "*Extension to find RCS file, some systems do not use ,v")
  48
  49 ;; Initialize the keymap if it isn't already
  50 (if (boundp 'diff-mode-map)
  51     nil
  52   (setq diff-mode-map (make-keymap))
  53   (suppress-keymap diff-mode-map)
  54   (define-key diff-mode-map "?" 'describe-mode)
  55   (define-key diff-mode-map "." 'diff-beginning-of-diff)
  56   (define-key diff-mode-map " " 'scroll-up)
  57   (define-key diff-mode-map "\177" 'scroll-down)
  58   (define-key diff-mode-map "n" 'diff-next-difference)
  59   (define-key diff-mode-map "p" 'diff-previous-difference)
  60   (define-key diff-mode-map "j" 'diff-show-difference))
  61
  62 ;;;###autoload
  63 (defun diff (old new)
  64   "Find and display the differences between OLD and NEW files.
  65 Interactively the current buffer's file name is the default for for NEW
  66 and a backup file for NEW is the default for OLD."
  67   (interactive
  68    (let (oldf newf)
  69      (reverse
  70       (list
  71        (setq newf (buffer-file-name)
  72              newf (if (and newf (file-exists-p newf))
  73                           (read-file-name
  74                            (concat "Diff new file: ("
  75                                    (file-name-nondirectory newf) ") ")
  76                            nil newf t)
  77                         (read-file-name "Diff new file: " nil nil t)))
  78        (setq oldf (file-newest-backup newf)
  79              oldf (if (and oldf (file-exists-p oldf))
  80                           (read-file-name
  81                            (concat "Diff original file: ("
  82                                    (file-name-nondirectory oldf) ") ")
  83                            (file-name-directory oldf) oldf t)
  84                         (read-file-name "Diff original file: "
  85                                         (file-name-directory newf) nil t)))))))
  86   (message "Comparing files %s %s..." new old)
  87   (setq new (expand-file-name new)
  88         old (expand-file-name old))
  89   (diff-internal-diff "diff" (append diff-switches (list new old)) nil))
  90
  91 (defun diff-sccs (new)
  92   "Find and display the differences between OLD and SCCS files."
  93   (interactive
  94    (let (newf)
  95       (list
  96        (setq newf (buffer-file-name)
  97              newf (if (and newf (file-exists-p newf))
  98                           (read-file-name
  99                            (concat "Diff new file: ("
 100                                    (file-name-nondirectory newf) ") ")
 101                            nil newf t)
 102                         (read-file-name "Diff new file: " nil nil t))))))
 103
 104   (message "Comparing SCCS file %s..." new)
 105   (setq new (expand-file-name new))
 106   (if (file-exists-p (concat
 107                       (file-name-directory new)
 108                       "SCCS/s."
 109                       (file-name-nondirectory new)))
 110       (diff-internal-diff "sccs"
 111                           (append '("diffs") diff-switches (list new))
 112                           2)
 113     (error "%s does not exist"
 114            (concat (file-name-directory new) "SCCS/s."
 115                    (file-name-nondirectory new)))))
 116
 117 (defun diff-rcs (new)
 118   "Find and display the differences between OLD and RCS files."
 119   (interactive
 120    (let (newf)
 121       (list
 122        (setq newf (buffer-file-name)
 123              newf (if (and newf (file-exists-p newf))
 124                           (read-file-name
 125                            (concat "Diff new file: ("
 126                                    (file-name-nondirectory newf) ") ")
 127                            nil newf t)
 128                         (read-file-name "Diff new file: " nil nil t))))))
 129
 130   (message "Comparing RCS file %s..." new)
 131   (let* ((fullname (expand-file-name new))
 132        (rcsfile (concat (file-name-directory fullname)
 133                        "RCS/"
 134                        (file-name-nondirectory fullname)
 135                        diff-rcs-extension)))
 136     (if (file-exists-p rcsfile)
 137       (diff-internal-diff "rcsdiff" (append diff-switches (list fullname)) 4)
 138       (error "%s does not exist" rcsfile))))
 139
 140 (defun diff-internal-diff (diff-command sw strip)
 141   (let ((buffer-read-only nil))
 142     (with-output-to-temp-buffer "*Diff Output*"
 143       (buffer-disable-undo standard-output)
 144       (save-excursion
 145         (set-buffer standard-output)
 146         (erase-buffer)
 147         (apply 'call-process diff-command nil t nil sw)))
 148     (set-buffer "*Diff Output*")
 149     (goto-char (point-min))
 150     (while sw
 151       (if (string= (car sw) "-c")
 152           ;; strip leading filenames from context diffs
 153           (progn (forward-line 2) (delete-region (point-min) (point))))
 154       (if (and (string= (car sw) "-C") (string= "sccs" diff-command))
 155           ;; strip stuff from SCCS context diffs
 156           (progn (forward-line 2) (delete-region (point-min) (point))))
 157       (setq sw (cdr sw)))
 158     (if strip
 159         ;; strip stuff from SCCS context diffs
 160         (progn (forward-line strip) (delete-region (point-min) (point)))))
 161   (diff-mode)
 162   (if (string= "0" diff-total-differences)
 163       (let ((buffer-read-only nil))
 164         (insert (message "There are no differences.")))
 165     (narrow-to-region (point) (progn
 166                                 (forward-line 1)
 167                                 (if (re-search-forward diff-search-pattern
 168                                                        nil t)
 169                                     (goto-char (match-beginning 0))
 170                                   (goto-char (point-max)))))
 171     (setq diff-current-difference "1")))
 172
 173 ;; Take a buffer full of Unix diff output and go into a mode to easily
 174 ;; see the next and previous difference
 175 (defun diff-mode ()
 176   "Diff Mode is used by \\[diff] for perusing the output from the diff program.
 177 All normal editing commands are turned off.  Instead, these are available:
 178 \\<diff-mode-map>
 179 \\[diff-beginning-of-diff]      Move point to start of this difference.
 180 \\[scroll-up]   Scroll to next screen of this difference.
 181 \\[scroll-down] Scroll to previous screen of this difference.
 182 \\[diff-next-difference]        Move to Next Difference.
 183 \\[diff-previous-difference]    Move to Previous Difference.
 184 \\[diff-show-difference]        Jump to difference specified by numeric position.
 185 "
 186   (interactive)
 187   (use-local-map diff-mode-map)
 188   (setq buffer-read-only t
 189         major-mode 'diff-mode
 190         mode-name "Diff"
 191         mode-line-modified "--- "
 192         mode-line-process
 193         '(" " diff-current-difference "/" diff-total-differences))
 194   (make-local-variable 'diff-current-difference)
 195   (set (make-local-variable 'diff-total-differences)
 196        (int-to-string (diff-count-differences))))
 197
 198 (defun diff-next-difference (n)
 199   "Go to the beginning of the next difference.
 200 Differences are delimited by `diff-search-pattern'."
 201   (interactive "p")
 202   (if (< n 0) (diff-previous-difference (- n))
 203     (if (zerop n) ()
 204       (goto-char (point-min))
 205       (forward-line 1) ; to get past the match for the start of this diff
 206       (widen)
 207       (if (re-search-forward diff-search-pattern nil 'move n)
 208           (let ((start (goto-char (match-beginning 0))))
 209             (forward-line 1)
 210             (if (re-search-forward diff-search-pattern nil 'move)
 211                 (goto-char (match-beginning 0)))
 212             (narrow-to-region start (point))
 213             (setq diff-current-difference
 214                   (int-to-string (+ n (string-to-int
 215                                        diff-current-difference)))))
 216         (re-search-backward diff-search-pattern nil)
 217         (narrow-to-region (point) (point-max))
 218         (message "No following differences.")
 219         (setq diff-current-difference diff-total-differences))
 220       (goto-char (point-min)))))
 221
 222 (defun diff-previous-difference (n)
 223   "Go the the beginning of the previous difference.
 224 Differences are delimited by `diff-search-pattern'."
 225   (interactive "p")
 226   (if (< n 0) (diff-next-difference (- n))
 227     (if (zerop n) ()
 228       (goto-char (point-min))
 229       (widen)
 230       (if (re-search-backward diff-search-pattern nil 'move n)
 231           (setq diff-current-difference
 232                 (int-to-string (- (string-to-int diff-current-difference) n)))
 233         (message "No previous differences.")
 234         (setq diff-current-difference "1"))
 235       (narrow-to-region (point) (progn
 236                                   (forward-line 1)
 237                                   (re-search-forward diff-search-pattern nil)
 238                                   (goto-char (match-beginning 0))))
 239       (goto-char (point-min)))))
 240
 241 (defun diff-show-difference (n)
 242   "Show difference number N (prefix argument)."
 243   (interactive "p")
 244   (let ((cur (string-to-int diff-current-difference)))
 245     (cond ((or (= n cur)
 246                (zerop n)
 247                (not (natnump n))) ; should signal an error perhaps.
 248            ;; just redisplay.
 249            (goto-char (point-min)))
 250           ((< n cur)
 251            (diff-previous-difference (- cur n)))
 252           ((> n cur)
 253            (diff-next-difference (- n cur))))))
 254
 255 (defun diff-beginning-of-diff ()
 256   "Go to beginning of current difference."
 257   (interactive)
 258   (goto-char (point-min)))
 259
 260 ;; This function counts up the number of differences in the buffer.
 261 (defun diff-count-differences ()
 262   "Count number of differences in the current buffer."
 263   (message "Counting differences...")
 264   (save-excursion
 265     (save-restriction
 266       (widen)
 267       (goto-char (point-min))
 268       (let ((cnt 0))
 269         (while (re-search-forward diff-search-pattern nil t)
 270           (setq cnt (1+ cnt)))
 271         (message "Counting differences...done (%d)" cnt)
 272         cnt))))
 273
 274 ;;; diff.el ends here