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;;; diff.el --- run `diff' in compilation-mode
;; Copyright (C) 1992, 1994, 1996, 2001, 2002, 2003, 2004, 2005, 2006,
;; 2007, 2008, 2009 Free Software Foundation, Inc.
;; Author: Frank Bresz
;; (according to authors.el)
;; Maintainer: FSF
;; 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 3 of the License, 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
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <>.
;;; 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:
(defgroup diff nil
"Comparing files with `diff'."
:group 'tools)
(defcustom diff-switches (purecopy "-c")
"A string or list of strings specifying switches to be passed to diff."
:type '(choice string (repeat string))
:group 'diff)
(defcustom diff-command (purecopy "diff")
"The command to use to run diff."
:type 'string
:group 'diff)
(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.")
;; prompt if prefix arg present
(defun diff-switches ()
(if current-prefix-arg
(read-string "Diff switches: "
(if (stringp diff-switches)
(mapconcat 'identity diff-switches " ")))))
(defun diff-sentinel (code)
"Code run when the diff process exits.
CODE is the exit code of the process. It should be 0 only if no diffs
were found."
(if diff-old-temp-file (delete-file diff-old-temp-file))
(if diff-new-temp-file (delete-file diff-new-temp-file))
(goto-char (point-max))
(let ((inhibit-read-only t))
(insert (format "\nDiff finished%s. %s\n"
(cond ((equal 0 code) " (no differences)")
((equal 2 code) " (diff error)")
(t ""))
(defvar diff-old-file nil)
(defvar diff-new-file nil)
(defvar diff-extra-args nil)
(defun diff (old new &optional switches no-async)
"Find and display the differences between OLD and NEW files.
When called interactively, read OLD and NEW using the minibuffer;
the default for NEW is the current buffer's file name, and the
default for OLD is a backup file for NEW, if one exists.
If NO-ASYNC is non-nil, call diff synchronously.
When called interactively with a prefix argument, prompt
interactively for diff switches. Otherwise, the switches
specified in `diff-switches' are passed to the diff command."
(let (oldf newf)
(setq newf (buffer-file-name)
newf (if (and newf (file-exists-p newf))
(concat "Diff new file (default "
(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))
(concat "Diff original file (default "
(file-name-nondirectory oldf) "): ")
(file-name-directory oldf) oldf t)
(read-file-name "Diff original file: "
(file-name-directory newf) nil t)))
(list oldf newf (diff-switches))))
(setq new (expand-file-name new)
old (expand-file-name old))
(or switches (setq switches diff-switches)) ; If not specified, use default.
(let* ((old-alt (file-local-copy old))
(new-alt (file-local-copy new))
(mapconcat 'identity
;; Use explicitly specified switches
,@(if (listp switches) switches (list switches))
,@(if (or old-alt new-alt)
(list "-L" old "-L" new))
,(shell-quote-argument (or old-alt old))
,(shell-quote-argument (or new-alt new)))
" "))
(buf (get-buffer-create "*Diff*"))
(thisdir default-directory)
(display-buffer buf)
(set-buffer buf)
(setq buffer-read-only nil)
(buffer-disable-undo (current-buffer))
(let ((inhibit-read-only t))
(buffer-enable-undo (current-buffer))
;; Use below 2 vars for backward-compatibility.
(set (make-local-variable 'diff-old-file) old)
(set (make-local-variable 'diff-new-file) new)
(set (make-local-variable 'diff-extra-args) (list switches no-async))
(set (make-local-variable 'revert-buffer-function)
(lambda (ignore-auto noconfirm)
(apply 'diff diff-old-file diff-new-file diff-extra-args)))
(set (make-local-variable 'diff-old-temp-file) old-alt)
(set (make-local-variable 'diff-new-temp-file) new-alt)
(setq default-directory thisdir)
(let ((inhibit-read-only t))
(insert command "\n"))
(if (and (not no-async) (fboundp 'start-process))
(setq proc (start-process "Diff" buf shell-file-name
shell-command-switch command))
(set-process-filter proc 'diff-process-filter)
proc (lambda (proc msg)
(with-current-buffer (process-buffer proc)
(diff-sentinel (process-exit-status proc))))))
;; Async processes aren't available.
(let ((inhibit-read-only t))
(call-process shell-file-name nil buf nil
shell-command-switch command)))))
(defun diff-process-filter (proc string)
(with-current-buffer (process-buffer proc)
(let ((moving (= (point) (process-mark proc))))
;; Insert the text, advancing the process marker.
(goto-char (process-mark proc))
(let ((inhibit-read-only t))
(insert string))
(set-marker (process-mark proc) (point)))
(if moving (goto-char (process-mark proc))))))
(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'.
With prefix arg, prompt for diff switches."
(interactive (list (read-file-name "Diff (file with backup): ")
(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)
(file-newest-backup fn))))
(provide 'diff)
;; arch-tag: 7de2c29b-7ea5-4b85-9b9d-72dd860de2bd
;;; diff.el ends here