-;; "DIFF" mode for handling output from unix diff utility.
-;; Copyright (C) 1990 Free Software Foundation, Inc.
-;; Written fpb@ittc.wec.com 1/27/89
+;;; diff.el --- Run `diff' in compilation-mode.
+
+;; Copyright (C) 1992, 1994, 1996 Free Software Foundation, Inc.
+
+;; Keywords: unix, tools
;; 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 1, or (at your option)
+;; 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,
;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
-
-;; todo: diff-switches flexibility:
-;; (defconst diff-switches-function
-;; '(lambda (file)
-;; (if (string-match "\\.el$" file)
-;; "-c -F\"^(\""
-;; "-p"))
-;; "Function to return switches to pass to the `diff' utility, in \\[diff].
-;; This function is called with one arg, a file name, and returns a string
-;; containing 0 or more arguments which are passed on to `diff'.
-;; NOTE: This is not an ordinary hook; it may not be a list of functions.")
-
-(defvar diff-switches nil
- "*A list of switches to pass to the diff program.")
-
-(defvar diff-search-pattern "^\\([0-9]\\|\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\*\\)"
- "Regular expression that delineates difference regions in diffs.")
-
-;; Initialize the keymap if it isn't already
-(if (boundp 'diff-mode-map)
- nil
- (setq diff-mode-map (make-keymap))
- (suppress-keymap diff-mode-map)
- (define-key diff-mode-map "?" 'describe-mode)
- (define-key diff-mode-map "." 'diff-beginning-of-diff)
- (define-key diff-mode-map " " 'scroll-up)
- (define-key diff-mode-map "\177" 'scroll-down)
- (define-key diff-mode-map "n" 'diff-next-difference)
- (define-key diff-mode-map "p" 'diff-previous-difference)
- (define-key diff-mode-map "j" 'diff-show-difference))
+;; 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:
+
+;; This package helps you explore differences between files, using the
+;; UNIX command diff(1). The commands are `diff' and `diff-backup'.
+;; You can specify options with `diff-switches'.
+
+;;; Code:
+
+(require 'compile)
+
+(defgroup diff nil
+ "Comparing files with `diff'."
+ :group 'tools)
+
+;;;###autoload
+(defcustom diff-switches "-c"
+ "*A string or list of strings specifying switches to be be passed to diff."
+ :type '(choice string (repeat string))
+ :group 'diff)
+
+;;;###autoload
+(defcustom diff-command "diff"
+ "*The command to use to run diff."
+ :type 'string
+ :group 'diff)
+
+(defvar diff-regexp-alist
+ '(
+ ;; -u format: @@ -OLDSTART,OLDEND +NEWSTART,NEWEND @@
+ ("^@@ -\\([0-9]+\\),[0-9]+ \\+\\([0-9]+\\),[0-9]+ @@$" 1 2)
+
+ ;; -c format: *** OLDSTART,OLDEND ****
+ ("^\\*\\*\\* \\([0-9]+\\),[0-9]+ \\*\\*\\*\\*$" 1 nil)
+ ;; --- NEWSTART,NEWEND ----
+ ("^--- \\([0-9]+\\),[0-9]+ ----$" nil 1)
+
+ ;; plain diff format: OLDSTART[,OLDEND]{a,d,c}NEWSTART[,NEWEND]
+ ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]\\([0-9]+\\)\\(,[0-9]+\\)?$" 1 3)
+
+ ;; -e (ed) format: OLDSTART[,OLDEND]{a,d,c}
+ ("^\\([0-9]+\\)\\(,[0-9]+\\)?[adc]$" 1)
+
+ ;; -f format: {a,d,c}OLDSTART[ OLDEND]
+ ;; -n format: {a,d,c}OLDSTART LINES-CHANGED
+ ("^[adc]\\([0-9]+\\)\\( [0-9]+\\)?$" 1)
+ )
+ "Alist (REGEXP OLD-IDX NEW-IDX) of regular expressions to match difference
+sections in \\[diff] output. If REGEXP matches, the OLD-IDX'th
+subexpression gives the line number in the old file, and NEW-IDX'th
+subexpression gives the line number in the new file. If OLD-IDX or NEW-IDX
+is nil, REGEXP matches only half a section.")
+
+(defvar diff-old-file nil
+ "This is the old file name in the comparison in this buffer.")
+(defvar diff-new-file nil
+ "This is the new file name in the comparison in this buffer.")
+(defvar diff-old-temp-file nil
+ "This is the name of a temp file to be deleted after diff finishes.")
+(defvar diff-new-temp-file nil
+ "This is the name of a temp file to be deleted after diff finishes.")
+
+;; See compilation-parse-errors-function (compile.el).
+(defun diff-parse-differences (limit-search find-at-least)
+ (setq compilation-error-list nil)
+ (message "Parsing differences...")
+
+ ;; Don't reparse diffs already seen at last parse.
+ (if compilation-parsing-end (goto-char compilation-parsing-end))
+
+ ;; Construct in REGEXP a regexp composed of all those in dired-regexp-alist.
+ (let ((regexp (mapconcat (lambda (elt)
+ (concat "\\(" (car elt) "\\)"))
+ diff-regexp-alist
+ "\\|"))
+ ;; (GROUP-IDX OLD-IDX NEW-IDX)
+ (groups (let ((subexpr 1))
+ (mapcar (lambda (elt)
+ (prog1
+ (cons subexpr
+ (mapcar (lambda (n)
+ (and n
+ (+ subexpr n)))
+ (cdr elt)))
+ (setq subexpr (+ subexpr 1
+ (count-regexp-groupings
+ (car elt))))))
+ diff-regexp-alist)))
+
+ (new-error
+ (function (lambda (file subexpr)
+ (setq compilation-error-list
+ (cons
+ (cons (save-excursion
+ ;; Report location of message
+ ;; at beginning of line.
+ (goto-char
+ (match-beginning subexpr))
+ (beginning-of-line)
+ (point-marker))
+ ;; Report location of corresponding text.
+ (let ((line (string-to-int
+ (buffer-substring
+ (match-beginning subexpr)
+ (match-end subexpr)))))
+ (save-excursion
+ (save-match-data
+ (set-buffer (find-file-noselect file)))
+ (save-excursion
+ (goto-line line)
+ (point-marker)))))
+ compilation-error-list)))))
+
+ (found-desired nil)
+ (num-loci-found 0)
+ g)
+
+ (while (and (not found-desired)
+ ;; We don't just pass LIMIT-SEARCH to re-search-forward
+ ;; because we want to find matches containing LIMIT-SEARCH
+ ;; but which extend past it.
+ (re-search-forward regexp nil t))
+
+ ;; Find which individual regexp matched.
+ (setq g groups)
+ (while (and g (null (match-beginning (car (car g)))))
+ (setq g (cdr g)))
+ (setq g (car g))
+
+ (if (nth 1 g) ;OLD-IDX
+ (funcall new-error diff-old-file (nth 1 g)))
+ (if (nth 2 g) ;NEW-IDX
+ (funcall new-error diff-new-file (nth 2 g)))
+
+ (setq num-loci-found (1+ num-loci-found))
+ (if (or (and find-at-least
+ (>= num-loci-found find-at-least))
+ (and limit-search (>= (point) limit-search)))
+ ;; We have found as many new loci as the user wants,
+ ;; or the user wanted a specific diff, and we're past it.
+ (setq found-desired t)))
+ (set-marker compilation-parsing-end
+ (if found-desired (point)
+ ;; Set to point-max, not point, so we don't perpetually
+ ;; parse the last bit of text when it isn't a diff header.
+ (point-max)))
+ (message "Parsing differences...done"))
+ (setq compilation-error-list (nreverse compilation-error-list)))
+
+(defun diff-process-setup ()
+ "Set up \`compilation-exit-message-function' for \`diff'."
+ ;; Avoid frightening people with "abnormally terminated"
+ ;; if diff finds differences.
+ (set (make-local-variable 'compilation-exit-message-function)
+ (lambda (status code msg)
+ (cond ((not (eq status 'exit))
+ (cons msg code))
+ ((zerop code)
+ '("finished (no differences)\n" . "no differences"))
+ ((= code 1)
+ '("finished\n" . "differences found"))
+ (t
+ (cons msg code))))))
;;;###autoload
-(defun diff (old new)
+(defun diff (old new &optional switches)
"Find and display the differences between OLD and NEW files.
-Interactively you are prompted with the current buffer's file name for NEW
-and what appears to be it's backup for OLD."
+Interactively the current buffer's file name is the default for NEW
+and a backup file for NEW is the default for OLD.
+With prefix arg, prompt for diff switches."
(interactive
- (let (oldf newf)
- (reverse
- (list
- (setq newf (buffer-file-name)
- newf (if (and newf (file-exists-p newf))
- (read-file-name
- (concat "Diff new file: ("
- (file-name-nondirectory newf) ") ")
- nil newf t)
- (read-file-name "Diff new file: " nil nil t)))
- (setq oldf (file-newest-backup newf)
- oldf (if (and oldf (file-exists-p oldf))
- (read-file-name
- (concat "Diff original file: ("
- (file-name-nondirectory oldf) ") ")
- (file-name-directory oldf) oldf t)
- (read-file-name "Diff original file: "
- (file-name-directory newf) nil t)))))))
- (message "Comparing files %s %s..." new old)
+ (nconc
+ (let (oldf newf)
+ (nreverse
+ (list
+ (setq newf (buffer-file-name)
+ newf (if (and newf (file-exists-p newf))
+ (read-file-name
+ (concat "Diff new file: ("
+ (file-name-nondirectory newf) ") ")
+ nil newf t)
+ (read-file-name "Diff new file: " nil nil t)))
+ (setq oldf (file-newest-backup newf)
+ oldf (if (and oldf (file-exists-p oldf))
+ (read-file-name
+ (concat "Diff original file: ("
+ (file-name-nondirectory oldf) ") ")
+ (file-name-directory oldf) oldf t)
+ (read-file-name "Diff original file: "
+ (file-name-directory newf) nil t))))))
+ (if current-prefix-arg
+ (list (read-string "Diff switches: "
+ (if (stringp diff-switches)
+ diff-switches
+ (mapconcat 'identity diff-switches " "))))
+ nil)))
(setq new (expand-file-name new)
old (expand-file-name old))
- (let ((buffer-read-only nil)
- (sw diff-switches))
- (with-output-to-temp-buffer "*Diff Output*"
- (buffer-disable-undo standard-output)
- (save-excursion
- (set-buffer standard-output)
- (erase-buffer)
- (apply 'call-process "diff" nil t nil
- (append diff-switches (list old new)))))
- (set-buffer "*Diff Output*")
- (goto-char (point-min))
- (while sw
- (if (string= (car sw) "-c")
- ;; strip leading filenames from context diffs
- (progn (forward-line 2) (delete-region (point-min) (point))))
- (setq sw (cdr sw))))
- (diff-mode)
- (if (string= "0" diff-total-differences)
- (let ((buffer-read-only nil))
- (insert (message "There are no differences.")))
- (narrow-to-region (point) (progn
- (forward-line 1)
- (if (re-search-forward diff-search-pattern
- nil t)
- (goto-char (match-beginning 0))
- (goto-char (point-max)))))
- (setq diff-current-difference "1")))
-
-;; Take a buffer full of Unix diff output and go into a mode to easily
-;; see the next and previous difference
-(defun diff-mode ()
- "Diff Mode is used by \\[diff] for perusing the output from the diff program.
-All normal editing commands are turned off. Instead, these are available:
-\\<diff-mode-map>
-\\[diff-beginning-of-diff] Move point to start of this difference.
-\\[scroll-up] Scroll to next screen of this difference.
-\\[scroll-down] Scroll to previous screen of this difference.
-\\[diff-next-difference] Move to Next Difference.
-\\[diff-previous-difference] Move to Previous Difference.
-\\[diff-show-difference] Jump to difference specified by numeric position.
-"
- (interactive)
- (use-local-map diff-mode-map)
- (setq buffer-read-only t
- major-mode 'diff-mode
- mode-name "Diff"
- mode-line-modified "--- "
- mode-line-process
- '(" " diff-current-difference "/" diff-total-differences))
- (make-local-variable 'diff-current-difference)
- (set (make-local-variable 'diff-total-differences)
- (int-to-string (diff-count-differences))))
-
-(defun diff-next-difference (n)
- "In diff mode, go to the beginning of the next difference as delimited
-by `diff-search-pattern'."
- (interactive "p")
- (if (< n 0) (diff-previous-difference (- n))
- (if (zerop n) ()
- (goto-char (point-min))
- (forward-line 1) ; to get past the match for the start of this diff
- (widen)
- (if (re-search-forward diff-search-pattern nil 'move n)
- (let ((start (goto-char (match-beginning 0))))
- (forward-line 1)
- (if (re-search-forward diff-search-pattern nil 'move)
- (goto-char (match-beginning 0)))
- (narrow-to-region start (point))
- (setq diff-current-difference
- (int-to-string (+ n (string-to-int
- diff-current-difference)))))
- (re-search-backward diff-search-pattern nil)
- (narrow-to-region (point) (point-max))
- (message "No following differences.")
- (setq diff-current-difference diff-total-differences))
- (goto-char (point-min)))))
-
-(defun diff-previous-difference (n)
- "In diff mode, go the the beginning of the previous difference as delimited
-by `diff-search-pattern'."
- (interactive "p")
- (if (< n 0) (diff-next-difference (- n))
- (if (zerop n) ()
- (goto-char (point-min))
- (widen)
- (if (re-search-backward diff-search-pattern nil 'move n)
- (setq diff-current-difference
- (int-to-string (- (string-to-int diff-current-difference) n)))
- (message "No previous differences.")
- (setq diff-current-difference "1"))
- (narrow-to-region (point) (progn
- (forward-line 1)
- (re-search-forward diff-search-pattern nil)
- (goto-char (match-beginning 0))))
- (goto-char (point-min)))))
-
-(defun diff-show-difference (n)
- "Show difference number N (prefix arg)."
- (interactive "p")
- (let ((cur (string-to-int diff-current-difference)))
- (cond ((or (= n cur)
- (zerop n)
- (not (natnump n))) ; should signal an error perhaps.
- ;; just redisplay.
- (goto-char (point-min)))
- ((< n cur)
- (diff-previous-difference (- cur n)))
- ((> n cur)
- (diff-next-difference (- n cur))))))
-
-(defun diff-beginning-of-diff ()
- "Go to beginning of current difference."
- (interactive)
- (goto-char (point-min)))
-
-;; This function counts up the number of differences in the buffer.
-(defun diff-count-differences ()
- "Count number of differences in the current buffer."
- (message "Counting differences...")
- (save-excursion
- (save-restriction
- (widen)
- (goto-char (point-min))
- (let ((cnt 0))
- (while (re-search-forward diff-search-pattern nil t)
- (setq cnt (1+ cnt)))
- (message "Counting differences...done (%d)" cnt)
- cnt))))
+ (let ((old-alt (file-local-copy old))
+ (new-alt (file-local-copy new))
+ buf)
+ (save-excursion
+ (let ((compilation-process-setup-function 'diff-process-setup)
+ (command
+ (mapconcat 'identity
+ (append (list diff-command)
+ ;; Use explicitly specified switches
+ (if switches
+ (if (consp switches)
+ switches (list switches))
+ ;; If not specified, use default.
+ (if (consp diff-switches)
+ diff-switches
+ (list diff-switches)))
+ (if (or old-alt new-alt)
+ (list "-L" old "-L" new))
+ (list
+ (shell-quote-argument (or old-alt old)))
+ (list
+ (shell-quote-argument (or new-alt new))))
+ " ")))
+ (setq buf
+ (compile-internal command
+ "No more differences" "Diff"
+ 'diff-parse-differences))
+ (set-buffer buf)
+ (set (make-local-variable 'diff-old-file) old)
+ (set (make-local-variable 'diff-new-file) new)
+ (set (make-local-variable 'diff-old-temp-file) old-alt)
+ (set (make-local-variable 'diff-new-temp-file) new-alt)
+ (set (make-local-variable 'compilation-finish-function)
+ (function (lambda (buff msg)
+ (if diff-old-temp-file
+ (delete-file diff-old-temp-file))
+ (if diff-new-temp-file
+ (delete-file diff-new-temp-file)))))
+ ;; When async processes aren't available, the compilation finish
+ ;; function doesn't get chance to run. Invoke it by hand.
+ (or (fboundp 'start-process)
+ (funcall compilation-finish-function nil nil))
+ buf))))
+
+;;;###autoload
+(defun diff-backup (file &optional switches)
+ "Diff this file with its backup file or vice versa.
+Uses the latest backup, if there are several numerical backups.
+If this file is a backup, diff it with its original.
+The backup file is the first file given to `diff'."
+ (interactive (list (read-file-name "Diff (file with backup): ")
+ (if current-prefix-arg
+ (read-string "Diff switches: "
+ (if (stringp diff-switches)
+ diff-switches
+ (mapconcat 'identity
+ diff-switches " ")))
+ nil)))
+ (let (bak ori)
+ (if (backup-file-name-p file)
+ (setq bak file
+ ori (file-name-sans-versions file))
+ (setq bak (or (diff-latest-backup-file file)
+ (error "No backup found for %s" file))
+ ori file))
+ (diff bak ori switches)))
+
+(defun diff-latest-backup-file (fn) ; actually belongs into files.el
+ "Return the latest existing backup of FILE, or nil."
+ (let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
+ (if handler
+ (funcall handler 'diff-latest-backup-file fn)
+ ;; First try simple backup, then the highest numbered of the
+ ;; numbered backups.
+ ;; Ignore the value of version-control because we look for existing
+ ;; backups, which maybe were made earlier or by another user with
+ ;; a different value of version-control.
+ (setq fn (file-chase-links (expand-file-name fn)))
+ (or
+ (let ((bak (make-backup-file-name fn)))
+ (if (file-exists-p bak) bak))
+ ;; We use BACKUPNAME to cope with backups stored in a different dir.
+ (let* ((backupname (car (find-backup-file-name fn)))
+ (dir (file-name-directory backupname))
+ (base-versions (concat (file-name-sans-versions
+ (file-name-nondirectory backupname))
+ ".~"))
+ ;; This is a fluid var for backup-extract-version.
+ (backup-extract-version-start (length base-versions)))
+ (concat dir
+ (car (sort
+ (file-name-all-completions base-versions dir)
+ (function
+ (lambda (fn1 fn2)
+ (> (backup-extract-version fn1)
+ (backup-extract-version fn2))))))))))))
+
+(provide 'diff)
+
+;;; diff.el ends here