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emacs/lisp/vc/diff.el

220 lines
8.2 KiB
EmacsLisp

;;; diff.el --- run `diff' in compilation-mode
;; Copyright (C) 1992, 1994, 1996, 2001-2011 Free Software Foundation, Inc.
;; Author: Frank Bresz
;; (according to authors.el)
;; Maintainer: FSF
;; Keywords: unix, vc, 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
;; 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. If not, see <http://www.gnu.org/licenses/>.
;;; 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:
(eval-when-compile (require 'cl))
(defgroup diff nil
"Comparing files with `diff'."
:group 'tools)
;;;###autoload
(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)
;;;###autoload
(defcustom diff-command (purecopy "diff")
"The command to use to run diff."
:type 'string
:group 'diff)
;; prompt if prefix arg present
(defun diff-switches ()
(if current-prefix-arg
(read-string "Diff switches: "
(if (stringp diff-switches)
diff-switches
(mapconcat 'identity diff-switches " ")))))
(defun diff-sentinel (code &optional old-temp-file new-temp-file)
"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 optional args OLD-TEMP-FILE and/or NEW-TEMP-FILE are non-nil,
delete the temporary files so named."
(if old-temp-file (delete-file old-temp-file))
(if new-temp-file (delete-file new-temp-file))
(save-excursion
(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 ""))
(current-time-string))))))
;;;###autoload
(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."
(interactive
(let* ((newf (if (and buffer-file-name (file-exists-p buffer-file-name))
(read-file-name
(concat "Diff new file (default "
(file-name-nondirectory buffer-file-name) "): ")
nil buffer-file-name t)
(read-file-name "Diff new file: " nil nil t)))
(oldf (file-newest-backup newf)))
(setq oldf (if (and oldf (file-exists-p oldf))
(read-file-name
(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))))
(display-buffer
(diff-no-select old new switches no-async)))
(defun diff-file-local-copy (file-or-buf)
(if (bufferp file-or-buf)
(with-current-buffer file-or-buf
(let ((tempfile (make-temp-file "buffer-content-")))
(write-region nil nil tempfile nil 'nomessage)
tempfile))
(file-local-copy file-or-buf)))
(defun diff-no-select (old new &optional switches no-async buf)
;; Noninteractive helper for creating and reverting diff buffers
(unless (bufferp new) (setq new (expand-file-name new)))
(unless (bufferp old) (setq old (expand-file-name old)))
(or switches (setq switches diff-switches)) ; If not specified, use default.
(unless (listp switches) (setq switches (list switches)))
(or buf (setq buf (get-buffer-create "*Diff*")))
(let* ((old-alt (diff-file-local-copy old))
(new-alt (diff-file-local-copy new))
(command
(mapconcat 'identity
`(,diff-command
;; Use explicitly specified switches
,@switches
,@(mapcar #'shell-quote-argument
(nconc
(when (or old-alt new-alt)
(list "-L" (if (stringp old)
old (prin1-to-string old))
"-L" (if (stringp new)
new (prin1-to-string new))))
(list (or old-alt old)
(or new-alt new)))))
" "))
(thisdir default-directory))
(with-current-buffer buf
(setq buffer-read-only t)
(buffer-disable-undo (current-buffer))
(let ((inhibit-read-only t))
(erase-buffer))
(buffer-enable-undo (current-buffer))
(diff-mode)
(set (make-local-variable 'revert-buffer-function)
(lexical-let ((old old) (new new)
(switches switches)
(no-async no-async))
(lambda (ignore-auto noconfirm)
(diff-no-select old new switches no-async (current-buffer)))))
(setq default-directory thisdir)
(let ((inhibit-read-only t))
(insert command "\n"))
(if (and (not no-async) (fboundp 'start-process))
(let ((proc (start-process "Diff" buf shell-file-name
shell-command-switch command)))
(set-process-filter proc 'diff-process-filter)
(lexical-let ((old-alt old-alt) (new-alt new-alt))
(set-process-sentinel
proc (lambda (proc msg)
(with-current-buffer (process-buffer proc)
(diff-sentinel (process-exit-status proc)
old-alt new-alt))))))
;; Async processes aren't available.
(let ((inhibit-read-only t))
(diff-sentinel
(call-process shell-file-name nil buf nil
shell-command-switch command)
old-alt new-alt))))
buf))
(defun diff-process-filter (proc string)
(with-current-buffer (process-buffer proc)
(let ((moving (= (point) (process-mark proc))))
(save-excursion
;; 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))))))
;;;###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'.
With prefix arg, prompt for diff switches."
(interactive (list (read-file-name "Diff (file with backup): ")
(diff-switches)))
(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))))
;;;###autoload
(defun diff-buffer-with-file (&optional buffer)
"View the differences between BUFFER and its associated file.
This requires the external program `diff' to be in your `exec-path'."
(interactive "bBuffer: ")
(with-current-buffer (get-buffer (or buffer (current-buffer)))
(diff buffer-file-name (current-buffer) nil 'noasync)))
(provide 'diff)
;;; diff.el ends here