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[emacs.git] / lisp / resume.el
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1 ;;; resume.el --- process command line args from within a suspended Emacs job
3 ;; Copyright (C) 1992 Free Software Foundation, Inc.
5 ;; Author: Joe Wells <jbw@bucsf.bu.edu>
6 ;; Adapted-By: ESR
7 ;; Keywords: processes
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software; you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
26 ;;; Commentary:
28 ;; The purpose of this library is to handle command line arguments
29 ;; when you resume an existing Emacs job.
31 ;; In order to use it, you must put this code in your .emacs file.
33 ;; (add-hook 'suspend-hook 'resume-suspend-hook)
34 ;; (add-hook 'suspend-resume-hook 'resume-process-args)
36 ;; You can't get the benefit of this library by using the `emacs' command,
37 ;; since that always starts a new Emacs job. Instead you must use a
38 ;; command called `edit' which knows how to resume an existing Emacs job
39 ;; if you have one, or start a new Emacs job if you don't have one.
41 ;; To define the `edit' command, run the script etc/emacs.csh (if you use CSH),
42 ;; or etc/emacs.bash if you use BASH. You would normally do this in your
43 ;; login script.
45 ;; Stephan Gildea suggested bug fix (gildea@bbn.com).
46 ;; Ideas from Michael DeCorte and other people.
48 ;;; Code:
50 (defvar resume-emacs-args-file (expand-file-name "~/.emacs_args")
51 "*This file is where arguments are placed for a suspended emacs job.")
53 (defvar resume-emacs-args-buffer " *Command Line Args*"
54 "Buffer that is used by resume-process-args.")
56 (defun resume-process-args ()
57 "Handler for command line args given when Emacs is resumed."
58 (let ((start-buffer (current-buffer))
59 (args-buffer (get-buffer-create resume-emacs-args-buffer))
60 length args
61 (command-line-default-directory default-directory))
62 (unwind-protect
63 (progn
64 (set-buffer args-buffer)
65 (erase-buffer)
66 ;; get the contents of resume-emacs-args-file
67 (condition-case ()
68 (let ((result (insert-file-contents resume-emacs-args-file)))
69 (setq length (car (cdr result))))
70 ;; the file doesn't exist, ergo no arguments
71 (file-error
72 (erase-buffer)
73 (setq length 0)))
74 (if (<= length 0)
75 (setq args nil)
76 ;; get the arguments from the buffer
77 (goto-char (point-min))
78 (while (not (eobp))
79 (skip-chars-forward " \t\n")
80 (let ((begin (point)))
81 (skip-chars-forward "^ \t\n")
82 (setq args (cons (buffer-substring begin (point)) args)))
83 (skip-chars-forward " \t\n"))
84 ;; arguments are now in reverse order
85 (setq args (nreverse args))
86 ;; make sure they're not read again
87 (erase-buffer))
88 (resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)
89 ;; if nothing was in buffer, args will be null
90 (or (null args)
91 (setq command-line-default-directory
92 (file-name-as-directory (car args))
93 args (cdr args)))
94 ;; actually process the arguments
95 (command-line-1 args))
96 ;; If the command line args don't result in a find-file, the
97 ;; buffer will be left in args-buffer. So we change back to the
98 ;; original buffer. The reason I don't just use
99 ;; (let ((default-directory foo))
100 ;; (command-line-1 args))
101 ;; in the context of the original buffer is because let does not
102 ;; work properly with buffer-local variables.
103 (if (eq (current-buffer) args-buffer)
104 (set-buffer start-buffer)))))
106 ;;;###autoload
107 (defun resume-suspend-hook ()
108 "Clear out the file used for transmitting args when Emacs resumes."
109 (save-excursion
110 (set-buffer (get-buffer-create resume-emacs-args-buffer))
111 (erase-buffer)
112 (resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)))
114 (defun resume-write-buffer-to-file (buffer file)
115 "Writes the contents of BUFFER into FILE, if permissions allow."
116 (if (not (file-writable-p file))
117 (error "No permission to write file %s" file))
118 (save-excursion
119 (set-buffer buffer)
120 (clear-visited-file-modtime)
121 (save-restriction
122 (widen)
123 (write-region (point-min) (point-max) file nil 'quiet))
124 (set-buffer-modified-p nil)))
126 (provide 'resume)
128 ;;; arch-tag: c90b2761-4803-4e58-a0ae-c4721368b628
129 ;;; resume.el ends here