Added 900-line support
[emacs.git] / lisp / resume.el
blobb1e6a58122f20ca1f1b58ebece679ba2452277c0
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 1, 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
23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
25 ;;; Commentary:
27 ;; Theory: the first time you start Emacs, command line arguments are
28 ;; handled normally. Then, you suspend your emacs job. When you want to edit
29 ;; something else, you type "emacs filename" as usual, but instead of
30 ;; starting a new emacs job, the old job is resumed instead, and the command
31 ;; line arguments are placed in a file where the old emacs job looks for
32 ;; them.
34 ;; Stephan Gildea suggested bug fix (gildea@bbn.com).
35 ;; Ideas from Michael DeCorte and other people.
37 ;; For csh users, insert the following alias in your .cshrc file
38 ;; (after removing the leading double semicolons, of course):
40 ;;# The following line could be just EMACS_CMD=emacs, but this depends on
41 ;;# your site.
42 ;;if (! $?EMACS_CMD) set EMACS_CMD=emacs
43 ;;set JOBS_FILE=/tmp/jobs.$USER.$$
44 ;;set ARGS_FILE=~/.emacs_args
45 ;;set STOP_PATT='^\[[0-9]*\] *[ +-] Stopped ............ '
46 ;;set SUNVIEW_CMD='emacstool -nw -f emacstool-init -f server-start'
47 ;;set X_CMD=\'\''$EMACS_CMD -i -f server-start'
48 ;;alias emacs \
49 ;;' \\
50 ;; jobs >! "$JOBS_FILE" \\
51 ;; && grep "$STOP_PATT$EMACS_CMD" "$JOBS_FILE" >& /dev/null \\
52 ;; && echo `pwd` \!* >! "$ARGS_FILE" && ""fg %$EMACS_CMD \\
53 ;;|| if (! -e ~/.emacs_server || -f ~/.emacs_server) set status=1 \\
54 ;; && emacsclient \!* \\
55 ;;|| @ status=1 - $?DISPLAY && eval "$X_CMD -i \!* &" \\
56 ;;|| @ status=1 - $?WINDOW_PARENT && eval "$SUNVIEW_CMD \!* &" \\
57 ;;|| ""$EMACS_CMD -nw \!* \\
58 ;;'
60 ;; The alias works as follows:
61 ;; 1. If there is a suspended Emacs job that is a child of the
62 ;; current shell, place its arguments in the ~/.emacs_args file and
63 ;; resume it.
64 ;; 2. Else if the ~/.emacs_server socket has been created, presume an
65 ;; Emacs server is running and attempt to connect to it. If no Emacs
66 ;; server is listening on the socket, this will fail.
67 ;; 3. Else if the DISPLAY environment variable is set, presume we are
68 ;; running under X Windows and start a new GNU Emacs process in the
69 ;; background as an X client.
70 ;; 4. Else if the WINDOW_PARENT environment variable is set, presume we
71 ;; are running under SunView and start an emacstool process in the
72 ;; background.
73 ;; 5. Else start a regular Emacs process.
75 ;; Notes:
76 ;; The output of the "jobs" command is not piped directly into "grep"
77 ;; because that would run the "jobs" command in a subshell.
78 ;; Before resuming a suspended emacs, the current directory and all
79 ;; command line arguments are placed in a file name ~/.emacs_args.
80 ;; The "-nw" switch to Emacs means no windowing system.
82 ;; Insert this in your .emacs file:
83 ;;(setq suspend-resume-hook 'resume-process-args)
84 ;;(setq suspend-hooks 'empty-args-file)
85 ;;(autoload 'empty-args-file "resume")
86 ;;(autoload 'resume-process-args "resume")
88 ;; Finally, put the rest in a file named "resume.el" in a lisp library
89 ;; directory.
91 ;;; Code:
93 (defvar emacs-args-file (expand-file-name "~/.emacs_args")
94 "*This file is where arguments are placed for a suspended emacs job.")
96 (defvar emacs-args-buffer " *Command Line Args*"
97 "Buffer that is used by resume-process-args.")
99 (defun resume-process-args ()
100 "This should be called from inside of suspend-resume-hook. This
101 grabs the contents of the file whose name is stored in
102 emacs-args-file, and processes these arguments like command line
103 options."
104 (let ((start-buffer (current-buffer))
105 (args-buffer (get-buffer-create emacs-args-buffer))
106 length args)
107 (unwind-protect
108 (progn
109 (set-buffer args-buffer)
110 (erase-buffer)
111 ;; get the contents of emacs-args-file
112 (condition-case ()
113 (let ((result (insert-file-contents emacs-args-file)))
114 (setq length (car (cdr result))))
115 ;; the file doesn't exist, ergo no arguments
116 (file-error
117 (erase-buffer)
118 (setq length 0)))
119 (if (<= length 0)
120 (setq args nil)
121 ;; get the arguments from the buffer
122 (goto-char (point-min))
123 (while (not (eobp))
124 (skip-chars-forward " \t\n")
125 (let ((begin (point)))
126 (skip-chars-forward "^ \t\n")
127 (setq args (cons (buffer-substring begin (point)) args)))
128 (skip-chars-forward " \t\n"))
129 ;; arguments are now in reverse order
130 (setq args (nreverse args))
131 ;; make sure they're not read again
132 (erase-buffer))
133 (write-buffer-to-file (current-buffer) emacs-args-file)
134 ;; if nothing was in buffer, args will be null
135 (or (null args)
136 (setq default-directory (file-name-as-directory (car args))
137 args (cdr args)))
138 ;; actually process the arguments
139 (command-line-1 args))
140 ;; If the command line args don't result in a find-file, the
141 ;; buffer will be left in args-buffer. So we change back to the
142 ;; original buffer. The reason I don't just use
143 ;; (let ((default-directory foo))
144 ;; (command-line-1 args))
145 ;; in the context of the original buffer is because let does not
146 ;; work properly with buffer-local variables.
147 (if (eq (current-buffer) args-buffer)
148 (set-buffer start-buffer)))))
150 (defun empty-args-file ()
151 "This empties the contents of the file whose name is specified by
152 emacs-args-file."
153 (save-excursion
154 (set-buffer (get-buffer-create emacs-args-buffer))
155 (erase-buffer)
156 (write-buffer-to-file (current-buffer) emacs-args-file)))
158 (defun write-buffer-to-file (buffer file)
159 "Writes the contents of BUFFER into FILE, if permissions allow."
160 (if (not (file-writable-p file))
161 (error "No permission to write file %s" file))
162 (save-excursion
163 (set-buffer buffer)
164 (clear-visited-file-modtime)
165 (save-restriction
166 (widen)
167 (write-region (point-min) (point-max) file nil 'quiet))
168 (set-buffer-modified-p nil)))
170 ;;; resume.el ends here