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1 ;;; server.el --- Lisp code for GNU Emacs running as server process.
3 ;; Copyright (C) 1986, 87, 92, 94, 95, 96, 97, 98, 99, 2000
4 ;; Free Software Foundation, Inc.
6 ;; Author: William Sommerfeld <wesommer@athena.mit.edu>
7 ;; Maintainer: FSF
8 ;; Keywords: processes
10 ;; Changes by peck@sun.com and by rms.
12 ;; This file is part of GNU Emacs.
14 ;; GNU Emacs is free software; you can redistribute it and/or modify
15 ;; it under the terms of the GNU General Public License as published by
16 ;; the Free Software Foundation; either version 2, or (at your option)
17 ;; any later version.
19 ;; GNU Emacs is distributed in the hope that it will be useful,
20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;; GNU General Public License for more details.
24 ;; You should have received a copy of the GNU General Public License
25 ;; along with GNU Emacs; see the file COPYING. If not, write to the
26 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
27 ;; Boston, MA 02111-1307, USA.
29 ;;; Commentary:
31 ;; This Lisp code is run in Emacs when it is to operate as
32 ;; a server for other processes.
34 ;; Load this library and do M-x server-edit to enable Emacs as a server.
35 ;; Emacs runs the program ../arch-lib/emacsserver as a subprocess
36 ;; for communication with clients. If there are no client buffers to edit,
37 ;; server-edit acts like (switch-to-buffer (other-buffer))
39 ;; When some other program runs "the editor" to edit a file,
40 ;; "the editor" can be the Emacs client program ../lib-src/emacsclient.
41 ;; This program transmits the file names to Emacs through
42 ;; the server subprocess, and Emacs visits them and lets you edit them.
44 ;; Note that any number of clients may dispatch files to emacs to be edited.
46 ;; When you finish editing a Server buffer, again call server-edit
47 ;; to mark that buffer as done for the client and switch to the next
48 ;; Server buffer. When all the buffers for a client have been edited
49 ;; and exited with server-edit, the client "editor" will return
50 ;; to the program that invoked it.
52 ;; Your editing commands and Emacs's display output go to and from
53 ;; the terminal in the usual way. Thus, server operation is possible
54 ;; only when Emacs can talk to the terminal at the time you invoke
55 ;; the client. This is possible in four cases:
57 ;; 1. On a window system, where Emacs runs in one window and the
58 ;; program that wants to use "the editor" runs in another.
60 ;; 2. On a multi-terminal system, where Emacs runs on one terminal and the
61 ;; program that wants to use "the editor" runs on another.
63 ;; 3. When the program that wants to use "the editor" is running
64 ;; as a subprocess of Emacs.
66 ;; 4. On a system with job control, when Emacs is suspended, the program
67 ;; that wants to use "the editor" will stop and display
68 ;; "Waiting for Emacs...". It can then be suspended, and Emacs can be
69 ;; brought into the foreground for editing. When done editing, Emacs is
70 ;; suspended again, and the client program is brought into the foreground.
72 ;; The buffer local variable "server-buffer-clients" lists
73 ;; the clients who are waiting for this buffer to be edited.
74 ;; The global variable "server-clients" lists all the waiting clients,
75 ;; and which files are yet to be edited for each.
77 ;;; Code:
79 (defgroup server nil
80 "Emacs running as a server process."
81 :group 'external)
83 (defcustom server-program (expand-file-name "emacsserver" exec-directory)
84 "*The program to use as the edit server."
85 :group 'server
86 :type 'string)
88 (defcustom server-visit-hook nil
89 "*List of hooks to call when visiting a file for the Emacs server."
90 :group 'server
91 :type '(repeat function))
93 (defcustom server-switch-hook nil
94 "*List of hooks to call when switching to a buffer for the Emacs server."
95 :group 'server
96 :type '(repeat function))
98 (defcustom server-done-hook nil
99 "*List of hooks to call when done editing a buffer for the Emacs server."
100 :group 'server
101 :type '(repeat function))
103 (defvar server-process nil
104 "the current server process")
106 (defvar server-previous-string "")
108 (defvar server-clients nil
109 "List of current server clients.
110 Each element is (CLIENTID BUFFERS...) where CLIENTID is a string
111 that can be given to the server process to identify a client.
112 When a buffer is marked as \"done\", it is removed from this list.")
114 (defvar server-buffer-clients nil
115 "List of clientids for clients requesting editing of current buffer.")
116 (make-variable-buffer-local 'server-buffer-clients)
117 ;; Changing major modes should not erase this local.
118 (put 'server-buffer-clients 'permanent-local t)
120 (defvar server-window nil
121 "*The window to use for selecting Emacs server buffers.
122 If nil, use the selected window.
123 If it is a frame, use the frame's selected window.")
125 (defcustom server-temp-file-regexp "^/tmp/Re\\|/draft$"
126 "*Regexp which should match filenames of temporary files
127 which are deleted and reused after each edit
128 by the programs that invoke the Emacs server."
129 :group 'server
130 :type 'regexp)
132 (defcustom server-kill-new-buffers t
133 "*Whether to kill buffers when done with them.
134 If non-nil, kill a buffer unless it already existed before editing
135 it with Emacs server. If nil, kill only buffers as specified by
136 `server-temp-file-regexp'.
137 Please note that only buffers are killed that still have a client,
138 i.e. buffers visited which \"emacsclient --no-wait\" are never killed in
139 this way."
140 :group 'server
141 :type 'boolean
142 :version "21.1")
144 (or (assq 'server-buffer-clients minor-mode-alist)
145 (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
147 (defvar server-existing-buffer nil
148 "Non-nil means a server buffer existed before visiting a file.")
149 (make-variable-buffer-local 'server-existing-buffer)
151 ;; If a *server* buffer exists,
152 ;; write STRING to it for logging purposes.
153 (defun server-log (string)
154 (if (get-buffer "*server*")
155 (save-excursion
156 (set-buffer "*server*")
157 (goto-char (point-max))
158 (insert (current-time-string) " " string)
159 (or (bolp) (newline)))))
161 (defun server-sentinel (proc msg)
162 (cond ((eq (process-status proc) 'exit)
163 (server-log (message "Server subprocess exited")))
164 ((eq (process-status proc) 'signal)
165 (server-log (message "Server subprocess killed")))))
167 ;;;###autoload
168 (defun server-start (&optional leave-dead)
169 "Allow this Emacs process to be a server for client processes.
170 This starts a server communications subprocess through which
171 client \"editors\" can send your editing commands to this Emacs job.
172 To use the server, set up the program `emacsclient' in the
173 Emacs distribution as your standard \"editor\".
175 Prefix arg means just kill any existing server communications subprocess."
176 (interactive "P")
177 ;; kill it dead!
178 (if server-process
179 (progn
180 (set-process-sentinel server-process nil)
181 (condition-case () (delete-process server-process) (error nil))))
182 ;; Delete the socket files made by previous server invocations.
183 (let* ((sysname (system-name))
184 (dot-index (string-match "\\." sysname)))
185 (condition-case ()
186 (delete-file (format "~/.emacs-server-%s" sysname))
187 (error nil))
188 (condition-case ()
189 (delete-file (format "/tmp/esrv%d-%s" (user-uid) sysname))
190 (error nil))
191 ;; In case the server file name was made with a domainless hostname,
192 ;; try deleting that name too.
193 (if dot-index
194 (let ((shortname (substring sysname 0 dot-index)))
195 (condition-case ()
196 (delete-file (format "~/.emacs-server-%s" shortname))
197 (error nil))
198 (condition-case ()
199 (delete-file (format "/tmp/esrv%d-%s" (user-uid) shortname))
200 (error nil)))))
201 ;; If this Emacs already had a server, clear out associated status.
202 (while server-clients
203 (let ((buffer (nth 1 (car server-clients))))
204 (server-buffer-done buffer)))
205 (if leave-dead
207 (if server-process
208 (server-log (message "Restarting server")))
209 ;; Using a pty is wasteful, and the separate session causes
210 ;; annoyance sometimes (some systems kill idle sessions).
211 (let ((process-connection-type nil))
212 (setq server-process (start-process "server" nil server-program)))
213 (set-process-sentinel server-process 'server-sentinel)
214 (set-process-filter server-process 'server-process-filter)
215 ;; We must receive file names without being decoded. Those are
216 ;; decoded by server-process-filter accoding to
217 ;; file-name-coding-system.
218 (set-process-coding-system server-process 'raw-text 'raw-text)
219 (process-kill-without-query server-process)))
221 ;Process a request from the server to edit some files.
222 ;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
223 (defun server-process-filter (proc string)
224 (server-log string)
225 (setq string (concat server-previous-string string))
226 ;; If the input is multiple lines,
227 ;; process each line individually.
228 (while (string-match "\n" string)
229 (let ((request (substring string 0 (match-beginning 0)))
230 (coding-system (and default-enable-multibyte-characters
231 (or file-name-coding-system
232 default-file-name-coding-system)))
233 client nowait
234 (files nil)
235 (lineno 1))
236 ;; Remove this line from STRING.
237 (setq string (substring string (match-end 0)))
238 (if (string-match "^Error: " request)
239 (message "Server error: %s" (substring request (match-end 0)))
240 (if (string-match "^Client: " request)
241 (progn
242 (setq request (substring request (match-end 0)))
243 (setq client (list (substring request 0 (string-match " " request))))
244 (setq request (substring request (match-end 0)))
245 (while (string-match "[^ ]+ " request)
246 (let ((arg
247 (substring request (match-beginning 0) (1- (match-end 0))))
248 (pos 0))
249 (setq request (substring request (match-end 0)))
250 (if (string-match "\\`-nowait" arg)
251 (setq nowait t)
252 (if (string-match "\\`\\+[0-9]+\\'" arg)
253 ;; ARG is a line number option.
254 (setq lineno (read (substring arg 1)))
255 ;; ARG is a file name.
256 ;; Collapse multiple slashes to single slashes.
257 (setq arg (command-line-normalize-file-name arg))
258 ;; Undo the quoting that emacsclient does
259 ;; for certain special characters.
260 (while (string-match "&." arg pos)
261 (setq pos (1+ (match-beginning 0)))
262 (let ((nextchar (aref arg pos)))
263 (cond ((= nextchar ?&)
264 (setq arg (replace-match "&" t t arg)))
265 ((= nextchar ?-)
266 (setq arg (replace-match "-" t t arg)))
268 (setq arg (replace-match " " t t arg))))))
269 ;; Now decode the file name if necessary.
270 (if coding-system
271 (setq arg (decode-coding-string arg coding-system)))
272 (setq files
273 (cons (list arg lineno)
274 files))
275 (setq lineno 1)))))
276 (server-visit-files files client nowait)
277 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
278 (if (null (cdr client))
279 ;; This client is empty; get rid of it immediately.
280 (progn
281 (send-string server-process
282 (format "Close: %s Done\n" (car client)))
283 (server-log (format "Close empty client: %s Done\n" (car client))))
284 ;; We visited some buffer for this client.
285 (or nowait
286 (setq server-clients (cons client server-clients)))
287 (server-switch-buffer (nth 1 client))
288 (run-hooks 'server-switch-hook)
289 (message (substitute-command-keys
290 "When done with a buffer, type \\[server-edit]"))))))))
291 ;; Save for later any partial line that remains.
292 (setq server-previous-string string))
294 (defun server-visit-files (files client &optional nowait)
295 "Finds FILES and returns the list CLIENT with the buffers nconc'd.
296 FILES is an alist whose elements are (FILENAME LINENUMBER).
297 NOWAIT non-nil means this client is not waiting for the results,
298 so don't mark these buffers specially, just visit them normally."
299 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
300 (let (client-record (last-nonmenu-event t) (obuf (current-buffer)))
301 ;; Restore the current buffer afterward, but not using save-excursion,
302 ;; because we don't want to save point in this buffer
303 ;; if it happens to be one of those specified by the server.
304 (unwind-protect
305 (while files
306 ;; If there is an existing buffer modified or the file is
307 ;; modified, revert it. If there is an existing buffer with
308 ;; deleted file, offer to write it.
309 (let* ((filen (car (car files)))
310 (obuf (get-file-buffer filen)))
311 (push filen file-name-history)
312 (if (and obuf (set-buffer obuf))
313 (cond ((file-exists-p filen)
314 (if (or (not (verify-visited-file-modtime obuf))
315 (buffer-modified-p obuf))
316 (revert-buffer t nil)))
318 (if (y-or-n-p
319 (concat "File no longer exists: "
320 filen
321 ", write buffer to file? "))
322 (write-file filen))))
323 (set-buffer (find-file-noselect filen))
324 (setq server-existing-buffer t)
325 (run-hooks 'server-visit-hook)))
326 (goto-line (nth 1 (car files)))
327 (if (not nowait)
328 (setq server-buffer-clients
329 (cons (car client) server-buffer-clients)))
330 (setq client-record (cons (current-buffer) client-record))
331 (setq files (cdr files)))
332 (set-buffer obuf))
333 (nconc client client-record)))
335 (defun server-buffer-done (buffer &optional for-killing)
336 "Mark BUFFER as \"done\" for its client(s).
337 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
338 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
339 or nil. KILLED is t if we killed BUFFER
340 \(typically, because it was visiting a temp file)."
341 (let ((running (eq (process-status server-process) 'run))
342 (next-buffer nil)
343 (killed nil)
344 (first t)
345 (old-clients server-clients))
346 (while old-clients
347 (let ((client (car old-clients)))
348 (or next-buffer
349 (setq next-buffer (nth 1 (memq buffer client))))
350 (delq buffer client)
351 ;; Delete all dead buffers from CLIENT.
352 (let ((tail client))
353 (while tail
354 (and (bufferp (car tail))
355 (null (buffer-name (car tail)))
356 (delq (car tail) client))
357 (setq tail (cdr tail))))
358 ;; If client now has no pending buffers,
359 ;; tell it that it is done, and forget it entirely.
360 (if (cdr client) nil
361 (if running
362 (progn
363 ;; Don't send emacsserver two commands in close succession.
364 ;; It cannot handle that.
365 (or first (sit-for 1))
366 (setq first nil)
367 (send-string server-process
368 (format "Close: %s Done\n" (car client)))
369 (server-log (format "Close: %s Done\n" (car client)))))
370 (setq server-clients (delq client server-clients))))
371 (setq old-clients (cdr old-clients)))
372 (if (and (bufferp buffer) (buffer-name buffer))
373 ;; We may or may not kill this buffer;
374 ;; if we do, do not call server-buffer-done recursively
375 ;; from kill-buffer-hook.
376 (let ((server-kill-buffer-running t))
377 (save-excursion
378 (set-buffer buffer)
379 (setq server-buffer-clients nil)
380 (run-hooks 'server-done-hook))
381 ;; Notice whether server-done-hook killed the buffer.
382 (if (null (buffer-name buffer))
383 (setq killed t)
384 ;; Don't bother killing or burying the buffer
385 ;; when we are called from kill-buffer.
386 (unless for-killing
387 (when (and (not killed)
388 server-kill-new-buffers
389 (save-excursion
390 (set-buffer buffer)
391 server-existing-buffer))
392 (setq killed t)
393 (bury-buffer buffer)
394 (kill-buffer buffer))
395 (unless killed
396 (if (server-temp-file-p buffer)
397 (progn
398 (kill-buffer buffer)
399 (setq killed t))
400 (bury-buffer buffer)))))))
401 (list next-buffer killed)))
403 (defun server-temp-file-p (buffer)
404 "Return non-nil if BUFFER contains a file considered temporary.
405 These are files whose names suggest they are repeatedly
406 reused to pass information to another program.
408 The variable `server-temp-file-regexp' controls which filenames
409 are considered temporary."
410 (and (buffer-file-name buffer)
411 (string-match server-temp-file-regexp (buffer-file-name buffer))))
413 (defun server-done ()
414 "Offer to save current buffer, mark it as \"done\" for clients.
415 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
416 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
417 or nil. KILLED is t if we killed BUFFER
418 \(typically, because it was visiting a temp file)."
419 (let ((buffer (current-buffer)))
420 (if server-buffer-clients
421 (progn
422 (if (server-temp-file-p buffer)
423 ;; For a temp file, save, and do make a non-numeric backup
424 ;; (unless make-backup-files is nil).
425 (let ((version-control nil)
426 (buffer-backed-up nil))
427 (save-buffer))
428 (if (and (buffer-modified-p)
429 buffer-file-name
430 (y-or-n-p (concat "Save file " buffer-file-name "? ")))
431 (save-buffer buffer)))
432 (server-buffer-done buffer)))))
434 ;; Ask before killing a server buffer.
435 ;; It was suggested to release its client instead,
436 ;; but I think that is dangerous--the client would proceed
437 ;; using whatever is on disk in that file. -- rms.
438 (defun server-kill-buffer-query-function ()
439 (or (not server-buffer-clients)
440 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
441 (buffer-name (current-buffer))))))
443 (add-hook 'kill-buffer-query-functions
444 'server-kill-buffer-query-function)
446 (defun server-kill-emacs-query-function ()
447 (let (live-client
448 (tail server-clients))
449 ;; See if any clients have any buffers that are still alive.
450 (while tail
451 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
452 (setq live-client t))
453 (setq tail (cdr tail)))
454 (or (not live-client)
455 (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
457 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
459 (defvar server-kill-buffer-running nil
460 "Non-nil while `server-kill-buffer' or `server-buffer-done' is running.")
462 ;; When a buffer is killed, inform the clients.
463 (add-hook 'kill-buffer-hook 'server-kill-buffer)
464 (defun server-kill-buffer ()
465 ;; Prevent infinite recursion if user has made server-done-hook
466 ;; call kill-buffer.
467 (or server-kill-buffer-running
468 (and server-buffer-clients
469 (let ((server-kill-buffer-running t))
470 (when server-process
471 (server-buffer-done (current-buffer) t))))))
473 (defun server-edit (&optional arg)
474 "Switch to next server editing buffer; say \"Done\" for current buffer.
475 If a server buffer is current, it is marked \"done\" and optionally saved.
476 When all of a client's buffers are marked as \"done\", the client is notified.
478 Temporary files such as MH <draft> files are always saved and backed up,
479 no questions asked. (The variable `make-backup-files', if nil, still
480 inhibits a backup; you can set it locally in a particular buffer to
481 prevent a backup for it.) The variable `server-temp-file-regexp' controls
482 which filenames are considered temporary.
484 If invoked with a prefix argument, or if there is no server process running,
485 starts server process and that is all. Invoked by \\[server-edit]."
486 (interactive "P")
487 (if (or arg
488 (not server-process)
489 (memq (process-status server-process) '(signal exit)))
490 (server-start nil)
491 (apply 'server-switch-buffer (server-done))))
493 (defun server-switch-buffer (&optional next-buffer killed-one)
494 "Switch to another buffer, preferably one that has a client.
495 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
496 ;; KILLED-ONE is t in a recursive call
497 ;; if we have already killed one temp-file server buffer.
498 ;; This means we should avoid the final "switch to some other buffer"
499 ;; since we've already effectively done that.
500 (cond ((and (windowp server-window)
501 (window-live-p server-window))
502 (select-window server-window))
503 ((framep server-window)
504 (if (not (frame-live-p server-window))
505 (setq server-window (make-frame)))
506 (select-window (frame-selected-window server-window))))
507 (if (window-minibuffer-p (selected-window))
508 (select-window (next-window nil 'nomini 0)))
509 ;; Move to a non-dedicated window, if we have one.
510 (select-window (some-window (lambda (w) (not (window-dedicated-p w)))
511 'nomini 'visible (selected-window)))
512 (set-window-dedicated-p (selected-window) nil)
513 (if next-buffer
514 (if (and (bufferp next-buffer)
515 (buffer-name next-buffer))
516 (switch-to-buffer next-buffer)
517 ;; If NEXT-BUFFER is a dead buffer,
518 ;; remove the server records for it
519 ;; and try the next surviving server buffer.
520 (apply 'server-switch-buffer
521 (server-buffer-done next-buffer)))
522 (if server-clients
523 (server-switch-buffer (nth 1 (car server-clients)) killed-one)
524 (if (not killed-one)
525 (switch-to-buffer (other-buffer))))))
527 (global-set-key "\C-x#" 'server-edit)
529 (provide 'server)
531 ;;; server.el ends here