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235 lines
8.4 KiB
EmacsLisp
235 lines
8.4 KiB
EmacsLisp
;;; diff.el --- run `diff' -*- lexical-binding: t -*-
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;; Copyright (C) 1992, 1994, 1996, 2001-2015 Free Software Foundation,
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;; Inc.
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;; Author: Frank Bresz
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;; (according to authors.el)
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;; Maintainer: emacs-devel@gnu.org
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;; Keywords: unix, vc, tools
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;; This package helps you explore differences between files, using the
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;; UNIX command diff(1). The commands are `diff' and `diff-backup'.
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;; You can specify options with `diff-switches'.
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;;; Code:
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(declare-function diff-setup-whitespace "diff-mode" ())
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(defgroup diff nil
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"Comparing files with `diff'."
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:group 'tools)
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;;;###autoload
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(defcustom diff-switches (purecopy "-c")
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"A string or list of strings specifying switches to be passed to diff."
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:type '(choice string (repeat string))
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:group 'diff)
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;;;###autoload
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(defcustom diff-command (purecopy "diff")
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"The command to use to run diff."
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:type 'string
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:group 'diff)
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;; prompt if prefix arg present
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(defun diff-switches ()
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(if current-prefix-arg
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(read-string "Diff switches: "
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(if (stringp diff-switches)
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diff-switches
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(mapconcat 'identity diff-switches " ")))))
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(defun diff-sentinel (code &optional old-temp-file new-temp-file)
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"Code run when the diff process exits.
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CODE is the exit code of the process. It should be 0 only if no diffs
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were found.
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If optional args OLD-TEMP-FILE and/or NEW-TEMP-FILE are non-nil,
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delete the temporary files so named."
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(if old-temp-file (delete-file old-temp-file))
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(if new-temp-file (delete-file new-temp-file))
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(diff-setup-whitespace)
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(goto-char (point-min))
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(save-excursion
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(goto-char (point-max))
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(let ((inhibit-read-only t))
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(insert (format "\nDiff finished%s. %s\n"
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(cond ((equal 0 code) " (no differences)")
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((equal 2 code) " (diff error)")
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(t ""))
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(current-time-string))))))
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;;;###autoload
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(defun diff (old new &optional switches no-async)
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"Find and display the differences between OLD and NEW files.
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When called interactively, read NEW, then OLD, using the
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minibuffer. The default for NEW is the current buffer's file
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name, and the default for OLD is a backup file for NEW, if one
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exists. If NO-ASYNC is non-nil, call diff synchronously.
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When called interactively with a prefix argument, prompt
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interactively for diff switches. Otherwise, the switches
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specified in the variable `diff-switches' are passed to the diff command."
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(interactive
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(let* ((newf (if (and buffer-file-name (file-exists-p buffer-file-name))
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(read-file-name
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(concat "Diff new file (default "
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(file-name-nondirectory buffer-file-name) "): ")
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nil buffer-file-name t)
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(read-file-name "Diff new file: " nil nil t)))
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(oldf (file-newest-backup newf)))
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(setq oldf (if (and oldf (file-exists-p oldf))
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(read-file-name
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(concat "Diff original file (default "
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(file-name-nondirectory oldf) "): ")
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(file-name-directory oldf) oldf t)
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(read-file-name "Diff original file: "
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(file-name-directory newf) nil t)))
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(list oldf newf (diff-switches))))
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(display-buffer
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(diff-no-select old new switches no-async)))
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(defun diff-file-local-copy (file-or-buf)
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(if (bufferp file-or-buf)
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(with-current-buffer file-or-buf
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(let ((tempfile (make-temp-file "buffer-content-")))
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(write-region nil nil tempfile nil 'nomessage)
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tempfile))
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(file-local-copy file-or-buf)))
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(defvar diff-use-labels 'check
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"Whether `diff-command' understands the \"--label\" option.
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Possible values are:
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t -- yes, it does
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nil -- no, it does not
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check -- try to probe whether it does")
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(defun diff-no-select (old new &optional switches no-async buf)
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;; Noninteractive helper for creating and reverting diff buffers
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(unless (bufferp new) (setq new (expand-file-name new)))
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(unless (bufferp old) (setq old (expand-file-name old)))
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(or switches (setq switches diff-switches)) ; If not specified, use default.
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(unless (listp switches) (setq switches (list switches)))
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(or buf (setq buf (get-buffer-create "*Diff*")))
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(when (eq 'check diff-use-labels)
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(setq diff-use-labels
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(with-temp-buffer
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(when (ignore-errors (call-process diff-command nil t nil "--help"))
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(if (search-backward "--label" nil t) t)))))
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(let* ((old-alt (diff-file-local-copy old))
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(new-alt (diff-file-local-copy new))
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(command
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(mapconcat 'identity
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`(,diff-command
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;; Use explicitly specified switches
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,@switches
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,@(mapcar #'shell-quote-argument
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(nconc
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(and (or old-alt new-alt)
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(eq diff-use-labels t)
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(list "--label"
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(if (stringp old) old
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(prin1-to-string old))
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"--label"
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(if (stringp new) new
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(prin1-to-string new))))
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(list (or old-alt old)
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(or new-alt new)))))
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" "))
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(thisdir default-directory))
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(with-current-buffer buf
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(setq buffer-read-only t)
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(buffer-disable-undo (current-buffer))
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(let ((inhibit-read-only t))
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(erase-buffer))
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(buffer-enable-undo (current-buffer))
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(diff-mode)
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(set (make-local-variable 'revert-buffer-function)
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(lambda (_ignore-auto _noconfirm)
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(diff-no-select old new switches no-async (current-buffer))))
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(setq default-directory thisdir)
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(let ((inhibit-read-only t))
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(insert command "\n"))
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(if (and (not no-async) (fboundp 'start-process))
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(let ((proc (start-process "Diff" buf shell-file-name
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shell-command-switch command)))
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(set-process-filter proc 'diff-process-filter)
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(set-process-sentinel
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proc (lambda (proc _msg)
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(with-current-buffer (process-buffer proc)
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(diff-sentinel (process-exit-status proc)
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old-alt new-alt)))))
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;; Async processes aren't available.
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(let ((inhibit-read-only t))
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(diff-sentinel
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(call-process shell-file-name nil buf nil
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shell-command-switch command)
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old-alt new-alt))))
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buf))
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(defun diff-process-filter (proc string)
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(with-current-buffer (process-buffer proc)
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(let ((moving (= (point) (process-mark proc))))
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(save-excursion
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;; Insert the text, advancing the process marker.
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(goto-char (process-mark proc))
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(let ((inhibit-read-only t))
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(insert string))
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(set-marker (process-mark proc) (point)))
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(if moving (goto-char (process-mark proc))))))
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;;;###autoload
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(defun diff-backup (file &optional switches)
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"Diff this file with its backup file or vice versa.
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Uses the latest backup, if there are several numerical backups.
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If this file is a backup, diff it with its original.
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The backup file is the first file given to `diff'.
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With prefix arg, prompt for diff switches."
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(interactive (list (read-file-name "Diff (file with backup): ")
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(diff-switches)))
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(let (bak ori)
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(if (backup-file-name-p file)
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(setq bak file
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ori (file-name-sans-versions file))
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(setq bak (or (diff-latest-backup-file file)
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(error "No backup found for %s" file))
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ori file))
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(diff bak ori switches)))
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;;;###autoload
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(defun diff-latest-backup-file (fn)
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"Return the latest existing backup of FILE, or nil."
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(let ((handler (find-file-name-handler fn 'diff-latest-backup-file)))
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(if handler
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(funcall handler 'diff-latest-backup-file fn)
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(file-newest-backup fn))))
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;;;###autoload
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(defun diff-buffer-with-file (&optional buffer)
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"View the differences between BUFFER and its associated file.
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This requires the external program `diff' to be in your `exec-path'."
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(interactive "bBuffer: ")
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(with-current-buffer (get-buffer (or buffer (current-buffer)))
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(diff buffer-file-name (current-buffer) nil 'noasync)))
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(provide 'diff)
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;;; diff.el ends here
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