(wait_reading_process_input): Use getpid when generating SIGIO.
[emacs.git] / lisp / resume.el
blobbd45ffb2df601088eb5f1cfadf7f7a2752eeb6d5
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 ;; Theory: the first time you start Emacs, command line arguments are
29 ;; handled normally. Then, you suspend your emacs job. When you want to edit
30 ;; something else, you type "emacs filename" as usual, but instead of
31 ;; starting a new emacs job, the old job is resumed instead, and the command
32 ;; line arguments are placed in a file where the old emacs job looks for
33 ;; them.
35 ;; Stephan Gildea suggested bug fix (gildea@bbn.com).
36 ;; Ideas from Michael DeCorte and other people.
38 ;; For csh users, insert the following alias in your .cshrc file
39 ;; (after removing the leading double semicolons, of course):
41 ;;# The following line could be just EMACS_CMD=emacs, but this depends on
42 ;;# your site.
43 ;;if (! $?EMACS_CMD) set EMACS_CMD=emacs
44 ;;set JOBS_FILE=/tmp/jobs.$USER.$$
45 ;;set ARGS_FILE=~/.emacs_args
46 ;;set STOP_PATT='^\[[0-9]*\] *[ +-] Stopped ............ '
47 ;;set SUNVIEW_CMD='emacstool -nw -f emacstool-init -f server-start'
48 ;;set X_CMD=\'\''$EMACS_CMD -i -f server-start'
49 ;;alias emacs \
50 ;;' \\
51 ;; jobs >! "$JOBS_FILE" \\
52 ;; && grep "$STOP_PATT$EMACS_CMD" "$JOBS_FILE" >& /dev/null \\
53 ;; && echo `pwd` \!* >! "$ARGS_FILE" && ""fg %$EMACS_CMD \\
54 ;;|| if (! -e ~/.emacs_server || -f ~/.emacs_server) set status=1 \\
55 ;; && emacsclient \!* \\
56 ;;|| @ status=1 - $?DISPLAY && eval "$X_CMD -i \!* &" \\
57 ;;|| @ status=1 - $?WINDOW_PARENT && eval "$SUNVIEW_CMD \!* &" \\
58 ;;|| ""$EMACS_CMD -nw \!* \\
59 ;;'
61 ;; The alias works as follows:
62 ;; 1. If there is a suspended Emacs job that is a child of the
63 ;; current shell, place its arguments in the ~/.emacs_args file and
64 ;; resume it.
65 ;; 2. Else if the ~/.emacs_server socket has been created, presume an
66 ;; Emacs server is running and attempt to connect to it. If no Emacs
67 ;; server is listening on the socket, this will fail.
68 ;; 3. Else if the DISPLAY environment variable is set, presume we are
69 ;; running under X Windows and start a new GNU Emacs process in the
70 ;; background as an X client.
71 ;; 4. Else if the WINDOW_PARENT environment variable is set, presume we
72 ;; are running under SunView and start an emacstool process in the
73 ;; background.
74 ;; 5. Else start a regular Emacs process.
76 ;; Notes:
77 ;; The output of the "jobs" command is not piped directly into "grep"
78 ;; because that would run the "jobs" command in a subshell.
79 ;; Before resuming a suspended emacs, the current directory and all
80 ;; command line arguments are placed in a file name ~/.emacs_args.
81 ;; The "-nw" switch to Emacs means no windowing system.
83 ;; Insert this in your .emacs file:
84 ;;(add-hook 'suspend-hook 'resume-suspend-hook)
86 ;; Finally, put the rest in a file named "resume.el" in a lisp library
87 ;; directory.
89 ;;; Code:
91 (defvar resume-emacs-args-file (expand-file-name "~/.emacs_args")
92 "*This file is where arguments are placed for a suspended emacs job.")
94 (defvar resume-emacs-args-buffer " *Command Line Args*"
95 "Buffer that is used by resume-process-args.")
97 (defun resume-process-args ()
98 "Handler for command line args given when Emacs is resumed."
99 (let ((start-buffer (current-buffer))
100 (args-buffer (get-buffer-create resume-emacs-args-buffer))
101 length args
102 (command-line-default-directory default-directory))
103 (unwind-protect
104 (progn
105 (set-buffer args-buffer)
106 (erase-buffer)
107 ;; get the contents of resume-emacs-args-file
108 (condition-case ()
109 (let ((result (insert-file-contents resume-emacs-args-file)))
110 (setq length (car (cdr result))))
111 ;; the file doesn't exist, ergo no arguments
112 (file-error
113 (erase-buffer)
114 (setq length 0)))
115 (if (<= length 0)
116 (setq args nil)
117 ;; get the arguments from the buffer
118 (goto-char (point-min))
119 (while (not (eobp))
120 (skip-chars-forward " \t\n")
121 (let ((begin (point)))
122 (skip-chars-forward "^ \t\n")
123 (setq args (cons (buffer-substring begin (point)) args)))
124 (skip-chars-forward " \t\n"))
125 ;; arguments are now in reverse order
126 (setq args (nreverse args))
127 ;; make sure they're not read again
128 (erase-buffer))
129 (resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)
130 ;; if nothing was in buffer, args will be null
131 (or (null args)
132 (setq command-line-default-directory
133 (file-name-as-directory (car args))
134 args (cdr args)))
135 ;; actually process the arguments
136 (command-line-1 args))
137 ;; If the command line args don't result in a find-file, the
138 ;; buffer will be left in args-buffer. So we change back to the
139 ;; original buffer. The reason I don't just use
140 ;; (let ((default-directory foo))
141 ;; (command-line-1 args))
142 ;; in the context of the original buffer is because let does not
143 ;; work properly with buffer-local variables.
144 (if (eq (current-buffer) args-buffer)
145 (set-buffer start-buffer)))))
147 ;;;###autoload
148 (defun resume-suspend-hook ()
149 "Clear out the file used for transmitting args when Emacs resumes."
150 (save-excursion
151 (set-buffer (get-buffer-create resume-emacs-args-buffer))
152 (erase-buffer)
153 (resume-write-buffer-to-file (current-buffer) resume-emacs-args-file)))
155 (defun resume-write-buffer-to-file (buffer file)
156 "Writes the contents of BUFFER into FILE, if permissions allow."
157 (if (not (file-writable-p file))
158 (error "No permission to write file %s" file))
159 (save-excursion
160 (set-buffer buffer)
161 (clear-visited-file-modtime)
162 (save-restriction
163 (widen)
164 (write-region (point-min) (point-max) file nil 'quiet))
165 (set-buffer-modified-p nil)))
167 (provide 'resume)
169 ;;; resume.el ends here