1
0
mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-01 08:17:38 +00:00
emacs/lisp/diff.el
1992-07-29 05:06:36 +00:00

230 lines
7.6 KiB
EmacsLisp

;;; diff.el --- Run `diff' in compilation-mode.
;; Copyright (C) 1992 Free Software Foundation, Inc.
;; Keyword: 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.
;;; Code:
(require 'compile)
(defvar diff-switches nil
"*A string or list of strings specifying switches to be be passed to 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.")
;; See compilation-parse-errors-function (compile.el).
(defun diff-parse-differences (limit-search)
(setq compilation-error-list nil)
(message "Parsing differences...")
;; Don't reparse diffs already seen at last parse.
(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 (set-marker (make-marker)
(match-beginning subexpr)
(current-buffer))
(let ((line (string-to-int
(buffer-substring
(match-beginning subexpr)
(match-end subexpr)))))
(save-excursion
(set-buffer (find-file-noselect file))
(save-excursion
(goto-line line)
(point-marker)))))
compilation-error-list)))))
(found-desired nil)
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)))
(and limit-search (>= (point) limit-search)
;; 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 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)))
(message "Comparing files %s %s..." new old)
(setq new (expand-file-name new)
old (expand-file-name old))
(let ((buf (compile-internal (mapconcat 'identity
(append '("diff")
(if (consp diff-switches)
diff-switches
(list diff-switches))
(list old)
(list new))
" ")
"No more differences" "Diff"
'diff-parse-differences)))
(save-excursion
(set-buffer buf)
(set (make-local-variable 'diff-old-file) old)
(set (make-local-variable 'diff-new-file) new))
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."
;; 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 (expand-file-name fn))
(or
(let ((bak (make-backup-file-name fn)))
(if (file-exists-p bak) bak))
(let* ((dir (file-name-directory fn))
(base-versions (concat (file-name-nondirectory fn) ".~"))
(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))))))))))
;;; diff.el ends here