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)
187 (setq request (substring request (match-end 0)))
188 (setq client (list (substring request 0 (string-match " " request))))
189 (setq request (substring request (match-end 0)))
190 (while (string-match "[^ ]+ " request)
192 (substring request (match-beginning 0) (1- (match-end 0)))))
193 (setq request (substring request (match-end 0)))
194 (if (string-match "\\`\\+[0-9]+\\'" arg)
195 (setq lineno (read (substring arg 1)))
197 (cons (list arg lineno)
200 (server-visit-files files client)
201 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
202 (setq server-clients (cons client server-clients))
203 (server-switch-buffer (nth 1 client))
204 (run-hooks 'server-switch-hook)
205 (message (substitute-command-keys
206 "When done with a buffer, type \\[server-edit]")))))))
207 ;; Save for later any partial line that remains.
208 (setq server-previous-string string))
210 (defun server-visit-files (files client)
211 "Finds FILES and returns the list CLIENT with the buffers nconc'd.
212 FILES is an alist whose elements are (FILENAME LINENUMBER)."
213 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
214 (let (client-record (last-nonmenu-event t) (obuf (current-buffer)))
215 ;; Restore the current buffer afterward, but not using save-excursion,
216 ;; because we don't want to save point in this buffer
217 ;; if it happens to be one of those specified by the server.
220 ;; If there is an existing buffer modified or the file is modified,
222 ;; If there is an existing buffer with deleted file, offer to write it.
223 (let* ((filen (car (car files)))
224 (obuf (get-file-buffer filen)))
225 (if (and obuf (set-buffer obuf))
226 (if (file-exists-p filen)
227 (if (or (not (verify-visited-file-modtime obuf))
228 (buffer-modified-p obuf))
229 (revert-buffer t nil))
231 (concat "File no longer exists: "
233 ", write buffer to file? "))
235 (set-buffer (find-file-noselect filen))
236 (run-hooks 'server-visit-hook)))
237 (goto-line (nth 1 (car files)))
238 (setq server-buffer-clients (cons (car client) server-buffer-clients))
239 (setq client-record (cons (current-buffer) client-record))
240 (setq files (cdr files)))
242 (nconc client client-record)))
244 (defun server-buffer-done (buffer)
245 "Mark BUFFER as \"done\" for its client(s).
246 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
247 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
248 or nil. KILLED is t if we killed BUFFER (because it was a temp file)."
249 (let ((running (eq (process-status server-process) 'run))
253 (old-clients server-clients))
255 (let ((client (car old-clients)))
257 (setq next-buffer (nth 1 (memq buffer client))))
259 ;; Delete all dead buffers from CLIENT.
262 (and (bufferp (car tail))
263 (null (buffer-name (car tail)))
264 (delq (car tail) client))
265 (setq tail (cdr tail))))
266 ;; If client now has no pending buffers,
267 ;; tell it that it is done, and forget it entirely.
271 ;; Don't send emacsserver two commands in close succession.
272 ;; It cannot handle that.
273 (or first (sit-for 1))
275 (send-string server-process
276 (format "Close: %s Done\n" (car client)))
277 (server-log (format "Close: %s Done\n" (car client)))))
278 (setq server-clients (delq client server-clients))))
279 (setq old-clients (cdr old-clients)))
280 (if (and (bufferp buffer) (buffer-name buffer))
284 (setq server-buffer-clients nil)
285 (run-hooks 'server-done-hook))
286 (if (server-temp-file-p buffer)
287 (progn (kill-buffer buffer)
289 (bury-buffer buffer))))
290 (list next-buffer killed)))
292 (defun server-temp-file-p (buffer)
293 "Return non-nil if BUFFER contains a file considered temporary.
294 These are files whose names suggest they are repeatedly
295 reused to pass information to another program.
297 The variable `server-temp-file-regexp' controls which filenames
298 are considered temporary."
299 (and (buffer-file-name buffer)
300 (string-match server-temp-file-regexp (buffer-file-name buffer))))
302 (defun server-done ()
303 "Offer to save current buffer, mark it as \"done\" for clients.
304 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
305 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
306 or nil. KILLED is t if we killed the BUFFER (because it was a temp file)."
307 (let ((buffer (current-buffer)))
308 (if server-buffer-clients
310 (if (server-temp-file-p buffer)
311 ;; For a temp file, save, and do make a non-numeric backup
312 ;; (unless make-backup-files is nil).
313 (let ((version-control nil)
314 (buffer-backed-up nil))
316 (if (and (buffer-modified-p)
317 (y-or-n-p (concat "Save file " buffer-file-name "? ")))
318 (save-buffer buffer)))
319 (server-buffer-done buffer)))))
321 ;; Ask before killing a server buffer.
322 ;; It was suggested to release its client instead,
323 ;; but I think that is dangerous--the client would proceed
324 ;; using whatever is on disk in that file. -- rms.
325 (defun server-kill-buffer-query-function ()
326 (or (not server-buffer-clients)
327 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
328 (buffer-name (current-buffer))))))
330 (add-hook 'kill-buffer-query-functions
331 'server-kill-buffer-query-function)
333 (defun server-kill-emacs-query-function ()
335 (tail server-clients))
336 ;; See if any clients have any buffers that are still alive.
338 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
339 (setq live-client t))
340 (setq tail (cdr tail)))
341 (or (not live-client)
342 (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
344 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
346 (defun server-edit (&optional arg)
347 "Switch to next server editing buffer; say \"Done\" for current buffer.
348 If a server buffer is current, it is marked \"done\" and optionally saved.
349 When all of a client's buffers are marked as \"done\", the client is notified.
351 Temporary files such as MH <draft> files are always saved and backed up,
352 no questions asked. (The variable `make-backup-files', if nil, still
353 inhibits a backup; you can set it locally in a particular buffer to
354 prevent a backup for it.) The variable `server-temp-file-regexp' controls
355 which filenames are considered temporary.
357 If invoked with a prefix argument, or if there is no server process running,
358 starts server process and that is all. Invoked by \\[server-edit]."
362 (memq (process-status server-process) '(signal exit)))
364 (apply 'server-switch-buffer (server-done))))
366 (defun server-switch-buffer (&optional next-buffer killed-one)
367 "Switch to another buffer, preferably one that has a client.
368 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
369 ;; KILLED-ONE is t in a recursive call
370 ;; if we have already killed one temp-file server buffer.
371 ;; This means we should avoid the final "switch to some other buffer"
372 ;; since we've already effectively done that.
373 (cond ((and (windowp server-window)
374 (window-live-p server-window))
375 (select-window server-window))
376 ((framep server-window)
377 (if (not (frame-live-p server-window))
378 (setq server-window (make-frame)))
379 (select-window (frame-selected-window server-window))))
380 (if (window-minibuffer-p (selected-window))
381 (select-window (next-window nil 'nomini 0)))
382 ;; Move to a non-dedicated window, if we have one.
383 (let ((last-window (previous-window nil 'nomini 0)))
384 (while (and (window-dedicated-p (selected-window))
385 (not (eq last-window (selected-window))))
386 (select-window (next-window nil 'nomini 0))))
387 (set-window-dedicated-p (selected-window) nil)
389 (if (and (bufferp next-buffer)
390 (buffer-name next-buffer))
391 (switch-to-buffer next-buffer)
392 ;; If NEXT-BUFFER is a dead buffer,
393 ;; remove the server records for it
394 ;; and try the next surviving server buffer.
395 (apply 'server-switch-buffer
396 (server-buffer-done next-buffer)))
398 (server-switch-buffer (nth 1 (car server-clients)) killed-one)
400 (switch-to-buffer (other-buffer))))))
402 (global-set-key "\C-x#" 'server-edit)
406 ;;; server.el ends here