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;;; diff.el --- Run `diff' in compilation-mode.
;; Copyright (C) 1992, 1994 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 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; 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.
;;; 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)
;;; This is duplicated in vc.el.
(defvar diff-switches "-c"
"*A string or list of strings specifying switches to be be passed to diff.")
(defvar diff-command "diff"
"*The command to use to run 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)))
(if found-desired
(setq compilation-parsing-end (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.
(setq compilation-parsing-end (point-max)))
(message "Parsing differences...done"))
(setq compilation-error-list (nreverse compilation-error-list)))
;;;###autoload
(defun diff (old new &optional switches)
"Find and display the differences between OLD and NEW files.
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
(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 ((old-alt (file-local-copy old))
(new-alt (file-local-copy new))
buf)
(unwind-protect
(let ((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))
(pop-to-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)))))
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))
".~"))
(bv-length (length base-versions)))
(concat dir
(car (sort
(file-name-all-completions base-versions dir)
;; bv-length is a fluid var for backup-extract-version:
(function
(lambda (fn1 fn2)
(> (backup-extract-version fn1)
(backup-extract-version fn2))))))))))))
(provide 'diff)
;;; diff.el ends here
|
