lisp/diff.el

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