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
   5 ;; Author: Frank P. Bresz <fpb@ittc.wec.com>
   6 ;; Maintainer: FSF
   7 ;; Created: 27 Jan 1989
   8 ;; Keyword: unix, tools
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  24 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; todo: diff-switches flexibility:
  29 ;; (defconst diff-switches-function
  30 ;;   '(lambda (file)
  31 ;;     (if (string-match "\\.el$" file)
  32 ;;       "-c -F\"^(\""
  33 ;;       "-p"))
  34 ;;  "Function to return switches to pass to the `diff' utility, in \\[diff].
  35 ;; This function is called with one arg, a file name, and returns a string
  36 ;; containing 0 or more arguments which are passed on to `diff'.
  37 ;; NOTE: This is not an ordinary hook; it may not be a list of functions.")
  38
  39 ;;  - fpb@ittc.wec.com - Sep 25, 1990
  40 ;; Added code to support sccs diffing.
  41 ;; also fixed one minor glitch in the
  42 ;; search for the pattern.  If you only 1 addition you won't find the end
  43 ;; of the pattern (minor)
  44
  45 ;;; Code:
  46
  47 (defvar diff-switches nil
  48   "*A list of switches to pass to the diff program.")
  49
  50 (defvar diff-search-pattern "^\\([0-9]\\|\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\)"
  51   "Regular expression that delineates difference regions in diffs.")
  52
  53 (defvar diff-rcs-extension ",v"
  54   "*Extension to find RCS file, some systems do not use ,v")
  55
  56 ;; Initialize the keymap if it isn't already
  57 (if (boundp 'diff-mode-map)
  58     nil
  59   (setq diff-mode-map (make-keymap))
  60   (suppress-keymap diff-mode-map)
  61   (define-key diff-mode-map "?" 'describe-mode)
  62   (define-key diff-mode-map "." 'diff-beginning-of-diff)
  63   (define-key diff-mode-map " " 'scroll-up)
  64   (define-key diff-mode-map "\177" 'scroll-down)
  65   (define-key diff-mode-map "n" 'diff-next-difference)
  66   (define-key diff-mode-map "p" 'diff-previous-difference)
  67   (define-key diff-mode-map "j" 'diff-show-difference))
  68
  69 ;;;###autoload
  70 (defun diff (old new)
  71   "Find and display the differences between OLD and NEW files.
  72 Interactively the current buffer's file name is the default for for NEW
  73 and a backup file for NEW is the default for OLD."
  74   (interactive
  75    (let (oldf newf)
  76      (reverse
  77       (list
  78        (setq newf (buffer-file-name)
  79              newf (if (and newf (file-exists-p newf))
  80                           (read-file-name
  81                            (concat "Diff new file: ("
  82                                    (file-name-nondirectory newf) ") ")
  83                            nil newf t)
  84                         (read-file-name "Diff new file: " nil nil t)))
  85        (setq oldf (file-newest-backup newf)
  86              oldf (if (and oldf (file-exists-p oldf))
  87                           (read-file-name
  88                            (concat "Diff original file: ("
  89                                    (file-name-nondirectory oldf) ") ")
  90                            (file-name-directory oldf) oldf t)
  91                         (read-file-name "Diff original file: "
  92                                         (file-name-directory newf) nil t)))))))
  93   (message "Comparing files %s %s..." new old)
  94   (setq new (expand-file-name new)
  95         old (expand-file-name old))
  96   (diff-internal-diff "diff" (append diff-switches (list new old)) nil))
  97
  98 (defun diff-sccs (new)
  99   "Find and display the differences between OLD and SCCS files."
 100   (interactive
 101    (let (newf)
 102       (list
 103        (setq newf (buffer-file-name)
 104              newf (if (and newf (file-exists-p newf))
 105                           (read-file-name
 106                            (concat "Diff new file: ("
 107                                    (file-name-nondirectory newf) ") ")
 108                            nil newf t)
 109                         (read-file-name "Diff new file: " nil nil t))))))
 110
 111   (message "Comparing SCCS file %s..." new)
 112   (setq new (expand-file-name new))
 113   (if (file-exists-p (concat
 114                       (file-name-directory new)
 115                       "SCCS/s."
 116                       (file-name-nondirectory new)))
 117       (diff-internal-diff "sccs"
 118                           (append '("diffs") diff-switches (list new))
 119                           2)
 120     (error "%s does not exist"
 121            (concat (file-name-directory new) "SCCS/s."
 122                    (file-name-nondirectory new)))))
 123
 124 (defun diff-rcs (new)
 125   "Find and display the differences between OLD and RCS files."
 126   (interactive
 127    (let (newf)
 128       (list
 129        (setq newf (buffer-file-name)
 130              newf (if (and newf (file-exists-p newf))
 131                           (read-file-name
 132                            (concat "Diff new file: ("
 133                                    (file-name-nondirectory newf) ") ")
 134                            nil newf t)
 135                         (read-file-name "Diff new file: " nil nil t))))))
 136
 137   (message "Comparing RCS file %s..." new)
 138   (let* ((fullname (expand-file-name new))
 139        (rcsfile (concat (file-name-directory fullname)
 140                        "RCS/"
 141                        (file-name-nondirectory fullname)
 142                        diff-rcs-extension)))
 143     (if (file-exists-p rcsfile)
 144       (diff-internal-diff "rcsdiff" (append diff-switches (list fullname)) 4)
 145       (error "%s does not exist" rcsfile))))
 146
 147 (defun diff-internal-diff (diff-command sw strip)
 148   (let ((buffer-read-only nil))
 149     (with-output-to-temp-buffer "*Diff Output*"
 150       (buffer-disable-undo standard-output)
 151       (save-excursion
 152         (set-buffer standard-output)
 153         (erase-buffer)
 154         (apply 'call-process diff-command nil t nil sw)))
 155     (set-buffer "*Diff Output*")
 156     (goto-char (point-min))
 157     (while sw
 158       (if (string= (car sw) "-c")
 159           ;; strip leading filenames from context diffs
 160           (progn (forward-line 2) (delete-region (point-min) (point))))
 161       (if (and (string= (car sw) "-C") (string= "sccs" diff-command))
 162           ;; strip stuff from SCCS context diffs
 163           (progn (forward-line 2) (delete-region (point-min) (point))))
 164       (setq sw (cdr sw)))
 165     (if strip
 166         ;; strip stuff from SCCS context diffs
 167         (progn (forward-line strip) (delete-region (point-min) (point)))))
 168   (diff-mode)
 169   (if (string= "0" diff-total-differences)
 170       (let ((buffer-read-only nil))
 171         (insert (message "There are no differences.")))
 172     (narrow-to-region (point) (progn
 173                                 (forward-line 1)
 174                                 (if (re-search-forward diff-search-pattern
 175                                                        nil t)
 176                                     (goto-char (match-beginning 0))
 177                                   (goto-char (point-max)))))
 178     (setq diff-current-difference "1")))
 179
 180 ;; Take a buffer full of Unix diff output and go into a mode to easily
 181 ;; see the next and previous difference
 182 (defun diff-mode ()
 183   "Diff Mode is used by \\[diff] for perusing the output from the diff program.
 184 All normal editing commands are turned off.  Instead, these are available:
 185 \\<diff-mode-map>
 186 \\[diff-beginning-of-diff]      Move point to start of this difference.
 187 \\[scroll-up]   Scroll to next screen of this difference.
 188 \\[scroll-down] Scroll to previous screen of this difference.
 189 \\[diff-next-difference]        Move to Next Difference.
 190 \\[diff-previous-difference]    Move to Previous Difference.
 191 \\[diff-show-difference]        Jump to difference specified by numeric position.
 192 "
 193   (interactive)
 194   (use-local-map diff-mode-map)
 195   (setq buffer-read-only t
 196         major-mode 'diff-mode
 197         mode-name "Diff"
 198         mode-line-modified "--- "
 199         mode-line-process
 200         '(" " diff-current-difference "/" diff-total-differences))
 201   (make-local-variable 'diff-current-difference)
 202   (set (make-local-variable 'diff-total-differences)
 203        (int-to-string (diff-count-differences))))
 204
 205 (defun diff-next-difference (n)
 206   "Go to the beginning of the next difference.
 207 Differences are delimited by `diff-search-pattern'."
 208   (interactive "p")
 209   (if (< n 0) (diff-previous-difference (- n))
 210     (if (zerop n) ()
 211       (goto-char (point-min))
 212       (forward-line 1) ; to get past the match for the start of this diff
 213       (widen)
 214       (if (re-search-forward diff-search-pattern nil 'move n)
 215           (let ((start (goto-char (match-beginning 0))))
 216             (forward-line 1)
 217             (if (re-search-forward diff-search-pattern nil 'move)
 218                 (goto-char (match-beginning 0)))
 219             (narrow-to-region start (point))
 220             (setq diff-current-difference
 221                   (int-to-string (+ n (string-to-int
 222                                        diff-current-difference)))))
 223         (re-search-backward diff-search-pattern nil)
 224         (narrow-to-region (point) (point-max))
 225         (message "No following differences.")
 226         (setq diff-current-difference diff-total-differences))
 227       (goto-char (point-min)))))
 228
 229 (defun diff-previous-difference (n)
 230   "Go the the beginning of the previous difference.
 231 Differences are delimited by `diff-search-pattern'."
 232   (interactive "p")
 233   (if (< n 0) (diff-next-difference (- n))
 234     (if (zerop n) ()
 235       (goto-char (point-min))
 236       (widen)
 237       (if (re-search-backward diff-search-pattern nil 'move n)
 238           (setq diff-current-difference
 239                 (int-to-string (- (string-to-int diff-current-difference) n)))
 240         (message "No previous differences.")
 241         (setq diff-current-difference "1"))
 242       (narrow-to-region (point) (progn
 243                                   (forward-line 1)
 244                                   (re-search-forward diff-search-pattern nil)
 245                                   (goto-char (match-beginning 0))))
 246       (goto-char (point-min)))))
 247
 248 (defun diff-show-difference (n)
 249   "Show difference number N (prefix argument)."
 250   (interactive "p")
 251   (let ((cur (string-to-int diff-current-difference)))
 252     (cond ((or (= n cur)
 253                (zerop n)
 254                (not (natnump n))) ; should signal an error perhaps.
 255            ;; just redisplay.
 256            (goto-char (point-min)))
 257           ((< n cur)
 258            (diff-previous-difference (- cur n)))
 259           ((> n cur)
 260            (diff-next-difference (- n cur))))))
 261
 262 (defun diff-beginning-of-diff ()
 263   "Go to beginning of current difference."
 264   (interactive)
 265   (goto-char (point-min)))
 266
 267 ;; This function counts up the number of differences in the buffer.
 268 (defun diff-count-differences ()
 269   "Count number of differences in the current buffer."
 270   (message "Counting differences...")
 271   (save-excursion
 272     (save-restriction
 273       (widen)
 274       (goto-char (point-min))
 275       (let ((cnt 0))
 276         (while (re-search-forward diff-search-pattern nil t)
 277           (setq cnt (1+ cnt)))
 278         (message "Counting differences...done (%d)" cnt)
 279         cnt))))
 280
 281 ;;; diff.el ends here