;;; resume.el --- process command line args from within a suspended Emacs job
;; Copyright (C) 1992 Free Software Foundation, Inc.
;; Author: Joe Wells <firstname.lastname@example.org>
;; Adapted-By: ESR
;; Keywords: processes
;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;; The purpose of this library is to handle command line arguments
;; when you resume an existing Emacs job.
;; In order to use it, you must put this code in your .emacs file.
;; (add-hook 'suspend-hook 'resume-suspend-hook)
;; (add-hook 'suspend-resume-hook 'resume-process-args)
;; You can't get the benefit of this library by using the `emacs' command,
;; since that always starts a new Emacs job. Instead you must use a
;; command called `edit' which knows how to resume an existing Emacs job
;; if you have one, or start a new Emacs job if you don't have one.
;; To define the `edit' command, run the script etc/emacs.csh (if you use CSH),
;; or etc/emacs.bash if you use BASH. You would normally do this in your
;; login script.
;; Stephan Gildea suggested bug fix (email@example.com).
;; Ideas from Michael DeCorte and other people.
(defvar resume-emacs-args-file (expand-file-name "~/.emacs_args")
"*This file is where arguments are placed for a suspended emacs job.")
(defvar resume-emacs-args-buffer " *Command Line Args*"
"Buffer that is used by resume-process-args.")
(defun resume-process-args ()
"Handler for command line args given when Emacs is resumed."
(let ((start-buffer (current-buffer))
(args-buffer (get-buffer-create resume-emacs-args-buffer))
;; get the contents of resume-emacs-args-file
(let ((result (insert-file-contents resume-emacs-args-file)))
(setq length (car (cdr result))))
;; the file doesn't exist, ergo no arguments
(setq length 0)))
(if (<= length 0)
(setq args nil)
;; get the arguments from the buffer
(while (not (eobp))
(skip-chars-forward " \t\n")
(let ((begin (point)))
(skip-chars-forward "^ \t\n")
(setq args (cons (buffer-substring begin (point)) args)))
(skip-chars-forward " \t\n"))
;; arguments are now in reverse order
(setq args (nreverse args))
;; make sure they're not read again
(resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)
;; if nothing was in buffer, args will be null
(or (null args)
(file-name-as-directory (car args))
args (cdr args)))
;; actually process the arguments
;; If the command line args don't result in a find-file, the
;; buffer will be left in args-buffer. So we change back to the
;; original buffer. The reason I don't just use
;; (let ((default-directory foo))
;; (command-line-1 args))
;; in the context of the original buffer is because let does not
;; work properly with buffer-local variables.
(if (eq (current-buffer) args-buffer)
(defun resume-suspend-hook ()
"Clear out the file used for transmitting args when Emacs resumes."
(set-buffer (get-buffer-create resume-emacs-args-buffer))
(resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)))
(defun resume-write-buffer-to-file (buffer file)
"Writes the contents of BUFFER into FILE, if permissions allow."
(if (not (file-writable-p file))
(error "No permission to write file %s" file))
(write-region (point-min) (point-max) file nil 'quiet))
;;; resume.el ends here