1 ;;; server.el --- Lisp code for GNU Emacs running as server process.
3 ;; Copyright (C) 1986, 1987, 1992, 1994, 1995 Free Software Foundation, Inc.
5 ;; Author: William Sommerfeld <wesommer@athena.mit.edu>
8 ;; Changes by peck@sun.com and by rms.
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software; you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation; either version 2, or (at your option)
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs; see the file COPYING. If not, write to
24 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
28 ;;; This Lisp code is run in Emacs when it is to operate as
29 ;;; a server for other processes.
31 ;;; Load this library and do M-x server-edit to enable Emacs as a server.
32 ;;; Emacs runs the program ../arch-lib/emacsserver as a subprocess
33 ;;; for communication with clients. If there are no client buffers to edit,
34 ;;; server-edit acts like (switch-to-buffer (other-buffer))
36 ;;; When some other program runs "the editor" to edit a file,
37 ;;; "the editor" can be the Emacs client program ../lib-src/emacsclient.
38 ;;; This program transmits the file names to Emacs through
39 ;;; the server subprocess, and Emacs visits them and lets you edit them.
41 ;;; Note that any number of clients may dispatch files to emacs to be edited.
43 ;;; When you finish editing a Server buffer, again call server-edit
44 ;;; to mark that buffer as done for the client and switch to the next
45 ;;; Server buffer. When all the buffers for a client have been edited
46 ;;; and exited with server-edit, the client "editor" will return
47 ;;; to the program that invoked it.
49 ;;; Your editing commands and Emacs's display output go to and from
50 ;;; the terminal in the usual way. Thus, server operation is possible
51 ;;; only when Emacs can talk to the terminal at the time you invoke
52 ;;; the client. This is possible in four cases:
54 ;;; 1. On a window system, where Emacs runs in one window and the
55 ;;; program that wants to use "the editor" runs in another.
57 ;;; 2. On a multi-terminal system, where Emacs runs on one terminal and the
58 ;;; program that wants to use "the editor" runs on another.
60 ;;; 3. When the program that wants to use "the editor" is running
61 ;;; as a subprocess of Emacs.
63 ;;; 4. On a system with job control, when Emacs is suspended, the program
64 ;;; that wants to use "the editor" will stop and display
65 ;;; "Waiting for Emacs...". It can then be suspended, and Emacs can be
66 ;;; brought into the foreground for editing. When done editing, Emacs is
67 ;;; suspended again, and the client program is brought into the foreground.
69 ;;; The buffer local variable "server-buffer-clients" lists
70 ;;; the clients who are waiting for this buffer to be edited.
71 ;;; The global variable "server-clients" lists all the waiting clients,
72 ;;; and which files are yet to be edited for each.
76 (defvar server-program (expand-file-name "emacsserver" exec-directory)
77 "*The program to use as the edit server.")
79 (defvar server-visit-hook nil
80 "*List of hooks to call when visiting a file for the Emacs server.")
82 (defvar server-switch-hook nil
83 "*List of hooks to call when switching to a buffer for the Emacs server.")
85 (defvar server-done-hook nil
86 "*List of hooks to call when done editing a buffer for the Emacs server.")
88 (defvar server-process nil
89 "the current server process")
91 (defvar server-previous-string "")
93 (defvar server-clients nil
94 "List of current server clients.
95 Each element is (CLIENTID BUFFERS...) where CLIENTID is a string
96 that can be given to the server process to identify a client.
97 When a buffer is marked as \"done\", it is removed from this list.")
99 (defvar server-buffer-clients nil
100 "List of clientids for clients requesting editing of current buffer.")
101 (make-variable-buffer-local 'server-buffer-clients)
102 ;; Changing major modes should not erase this local.
103 (put 'server-buffer-clients 'permanent-local t)
105 (defvar server-window nil
106 "*The window to use for selecting Emacs server buffers.
107 If nil, use the selected window.
108 If it is a frame, use the frame's selected window.")
110 (defvar server-temp-file-regexp "^/tmp/Re\\|/draft$"
111 "*Regexp which should match filenames of temporary files
112 which are deleted and reused after each edit
113 by the programs that invoke the emacs server.")
115 (or (assq 'server-buffer-clients minor-mode-alist)
116 (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
118 ;; If a *server* buffer exists,
119 ;; write STRING to it for logging purposes.
120 (defun server-log (string)
121 (if (get-buffer "*server*")
123 (set-buffer "*server*")
124 (goto-char (point-max))
126 (or (bobp) (newline)))))
128 (defun server-sentinel (proc msg)
129 (cond ((eq (process-status proc) 'exit)
130 (server-log (message "Server subprocess exited")))
131 ((eq (process-status proc) 'signal)
132 (server-log (message "Server subprocess killed")))))
135 (defun server-start (&optional leave-dead)
136 "Allow this Emacs process to be a server for client processes.
137 This starts a server communications subprocess through which
138 client \"editors\" can send your editing commands to this Emacs job.
139 To use the server, set up the program `emacsclient' in the
140 Emacs distribution as your standard \"editor\".
142 Prefix arg means just kill any existing server communications subprocess."
147 (set-process-sentinel server-process nil)
148 (condition-case () (delete-process server-process) (error nil))))
149 (condition-case () (delete-file "~/.emacs_server") (error nil))
151 (delete-file (format "/tmp/esrv%d-%s" (user-uid) (system-name)))
153 ;; If we already had a server, clear out associated status.
154 (while server-clients
155 (let ((buffer (nth 1 (car server-clients))))
156 (server-buffer-done buffer)))
160 (server-log (message "Restarting server")))
161 ;; Using a pty is wasteful, and the separate session causes
162 ;; annoyance sometimes (some systems kill idle sessions).
163 (let ((process-connection-type nil))
164 (setq server-process (start-process "server" nil server-program)))
165 (set-process-sentinel server-process 'server-sentinel)
166 (set-process-filter server-process 'server-process-filter)
167 (process-kill-without-query server-process)))
169 ;Process a request from the server to edit some files.
170 ;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
171 (defun server-process-filter (proc string)
173 (setq string (concat server-previous-string string))
174 ;; If the input is multiple lines,
175 ;; process each line individually.
176 (while (string-match "\n" string)
177 (let ((request (substring string 0 (match-beginning 0)))
181 ;; Remove this line from STRING.
182 (setq string (substring string (match-end 0)))
183 (if (string-match "^Error: " request)
184 (message (concat "Server error: " (substring request (match-end 0))))
185 (if (string-match "^Client: " request)
186 (setq request (substring request (match-end 0))))
187 (setq client (list (substring request 0 (string-match " " request))))
188 (setq request (substring request (match-end 0)))
189 (while (string-match "[^ ]+ " request)
191 (substring request (match-beginning 0) (1- (match-end 0)))))
192 (setq request (substring request (match-end 0)))
193 (if (string-match "\\`\\+[0-9]+\\'" arg)
194 (setq lineno (read (substring arg 1)))
196 (cons (list arg lineno)
199 (server-visit-files files client)
200 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
201 (setq server-clients (cons client server-clients))
202 (server-switch-buffer (nth 1 client))
203 (run-hooks 'server-switch-hook)
204 (message (substitute-command-keys
205 "When done with a buffer, type \\[server-edit]")))))
206 ;; Save for later any partial line that remains.
207 (setq server-previous-string string))
209 (defun server-visit-files (files client)
210 "Finds FILES and returns the list CLIENT with the buffers nconc'd.
211 FILES is an alist whose elements are (FILENAME LINENUMBER)."
212 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
213 (let (client-record (last-nonmenu-event t) (obuf (current-buffer)))
214 ;; Restore the current buffer afterward, but not using save-excursion,
215 ;; because we don't want to save point in this buffer
216 ;; if it happens to be one of those specified by the server.
219 ;; If there is an existing buffer modified or the file is modified,
221 ;; If there is an existing buffer with deleted file, offer to write it.
222 (let* ((filen (car (car files)))
223 (obuf (get-file-buffer filen)))
224 (if (and obuf (set-buffer obuf))
225 (if (file-exists-p filen)
226 (if (or (not (verify-visited-file-modtime obuf))
227 (buffer-modified-p obuf))
228 (revert-buffer t nil))
230 (concat "File no longer exists: "
232 ", write buffer to file? "))
234 (set-buffer (find-file-noselect filen))
235 (run-hooks 'server-visit-hook)))
236 (goto-line (nth 1 (car files)))
237 (setq server-buffer-clients (cons (car client) server-buffer-clients))
238 (setq client-record (cons (current-buffer) client-record))
239 (setq files (cdr files)))
241 (nconc client client-record)))
243 (defun server-buffer-done (buffer)
244 "Mark BUFFER as \"done\" for its client(s).
245 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
246 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
247 or nil. KILLED is t if we killed BUFFER (because it was a temp file)."
248 (let ((running (eq (process-status server-process) 'run))
252 (old-clients server-clients))
254 (let ((client (car old-clients)))
256 (setq next-buffer (nth 1 (memq buffer client))))
258 ;; Delete all dead buffers from CLIENT.
261 (and (bufferp (car tail))
262 (null (buffer-name (car tail)))
263 (delq (car tail) client))
264 (setq tail (cdr tail))))
265 ;; If client now has no pending buffers,
266 ;; tell it that it is done, and forget it entirely.
270 ;; Don't send emacsserver two commands in close succession.
271 ;; It cannot handle that.
272 (or first (sit-for 1))
274 (send-string server-process
275 (format "Close: %s Done\n" (car client)))
276 (server-log (format "Close: %s Done\n" (car client)))))
277 (setq server-clients (delq client server-clients))))
278 (setq old-clients (cdr old-clients)))
279 (if (and (bufferp buffer) (buffer-name buffer))
283 (setq server-buffer-clients nil)
284 (run-hooks 'server-done-hook))
285 (if (server-temp-file-p buffer)
286 (progn (kill-buffer buffer)
288 (bury-buffer buffer))))
289 (list next-buffer killed)))
291 (defun server-temp-file-p (buffer)
292 "Return non-nil if BUFFER contains a file considered temporary.
293 These are files whose names suggest they are repeatedly
294 reused to pass information to another program.
296 The variable `server-temp-file-regexp' controls which filenames
297 are considered temporary."
298 (and (buffer-file-name buffer)
299 (string-match server-temp-file-regexp (buffer-file-name buffer))))
301 (defun server-done ()
302 "Offer to save current buffer, mark it as \"done\" for clients.
303 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
304 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
305 or nil. KILLED is t if we killed the BUFFER (because it was a temp file)."
306 (let ((buffer (current-buffer)))
307 (if server-buffer-clients
309 (if (server-temp-file-p buffer)
310 ;; For a temp file, save, and do make a non-numeric backup
311 ;; (unless make-backup-files is nil).
312 (let ((version-control nil)
313 (buffer-backed-up nil))
315 (if (and (buffer-modified-p)
316 (y-or-n-p (concat "Save file " buffer-file-name "? ")))
317 (save-buffer buffer)))
318 (server-buffer-done buffer)))))
320 ;; Ask before killing a server buffer.
321 ;; It was suggested to release its client instead,
322 ;; but I think that is dangerous--the client would proceed
323 ;; using whatever is on disk in that file. -- rms.
324 (defun server-kill-buffer-query-function ()
325 (or (not server-buffer-clients)
326 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
327 (buffer-name (current-buffer))))))
329 (add-hook 'kill-buffer-query-functions
330 'server-kill-buffer-query-function)
332 (defun server-kill-emacs-query-function ()
334 (tail server-clients))
335 ;; See if any clients have any buffers that are still alive.
337 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
338 (setq live-client t))
339 (setq tail (cdr tail)))
340 (or (not live-client)
341 (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
343 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
345 (defun server-edit (&optional arg)
346 "Switch to next server editing buffer; say \"Done\" for current buffer.
347 If a server buffer is current, it is marked \"done\" and optionally saved.
348 When all of a client's buffers are marked as \"done\", the client is notified.
350 Temporary files such as MH <draft> files are always saved and backed up,
351 no questions asked. (The variable `make-backup-files', if nil, still
352 inhibits a backup; you can set it locally in a particular buffer to
353 prevent a backup for it.) The variable `server-temp-file-regexp' controls
354 which filenames are considered temporary.
356 If invoked with a prefix argument, or if there is no server process running,
357 starts server process and that is all. Invoked by \\[server-edit]."
361 (memq (process-status server-process) '(signal exit)))
363 (apply 'server-switch-buffer (server-done))))
365 (defun server-switch-buffer (&optional next-buffer killed-one)
366 "Switch to another buffer, preferably one that has a client.
367 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
368 ;; KILLED-ONE is t in a recursive call
369 ;; if we have already killed one temp-file server buffer.
370 ;; This means we should avoid the final "switch to some other buffer"
371 ;; since we've already effectively done that.
372 (cond ((and (windowp server-window)
373 (window-live-p server-window))
374 (select-window server-window))
375 ((framep server-window)
376 (if (not (frame-live-p server-window))
377 (setq server-window (make-frame)))
378 (select-window (frame-selected-window server-window))))
379 (if (window-minibuffer-p (selected-window))
380 (select-window (next-window nil 'nomini 0)))
381 ;; Move to a non-dedicated window, if we have one.
382 (let ((last-window (previous-window nil 'nomini 0)))
383 (while (and (window-dedicated-p (selected-window))
384 (not (eq last-window (selected-window))))
385 (select-window (next-window nil 'nomini 0))))
386 (set-window-dedicated-p (selected-window) nil)
388 (if (and (bufferp next-buffer)
389 (buffer-name next-buffer))
390 (switch-to-buffer next-buffer)
391 ;; If NEXT-BUFFER is a dead buffer,
392 ;; remove the server records for it
393 ;; and try the next surviving server buffer.
394 (apply 'server-switch-buffer
395 (server-buffer-done next-buffer)))
397 (server-switch-buffer (nth 1 (car server-clients)) killed-one)
399 (switch-to-buffer (other-buffer))))))
401 (global-set-key "\C-x#" 'server-edit)
405 ;;; server.el ends here