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[emacs.git] / lisp / server.el
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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, 1997 Free Software Foundation, Inc.
5 ;; Author: William Sommerfeld <wesommer@athena.mit.edu>
6 ;; Maintainer: FSF
7 ;; Keywords: processes
9 ;; Changes by peck@sun.com and by rms.
11 ;; This file is part of GNU Emacs.
13 ;; GNU Emacs is free software; you can redistribute it and/or modify
14 ;; it under the terms of the GNU General Public License as published by
15 ;; the Free Software Foundation; either version 2, or (at your option)
16 ;; any later version.
18 ;; GNU Emacs is distributed in the hope that it will be useful,
19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ;; GNU General Public License for more details.
23 ;; You should have received a copy of the GNU General Public License
24 ;; along with GNU Emacs; see the file COPYING. If not, write to the
25 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
26 ;; Boston, MA 02111-1307, USA.
28 ;;; Commentary:
30 ;; This Lisp code is run in Emacs when it is to operate as
31 ;; a server for other processes.
33 ;; Load this library and do M-x server-edit to enable Emacs as a server.
34 ;; Emacs runs the program ../arch-lib/emacsserver as a subprocess
35 ;; for communication with clients. If there are no client buffers to edit,
36 ;; server-edit acts like (switch-to-buffer (other-buffer))
38 ;; When some other program runs "the editor" to edit a file,
39 ;; "the editor" can be the Emacs client program ../lib-src/emacsclient.
40 ;; This program transmits the file names to Emacs through
41 ;; the server subprocess, and Emacs visits them and lets you edit them.
43 ;; Note that any number of clients may dispatch files to emacs to be edited.
45 ;; When you finish editing a Server buffer, again call server-edit
46 ;; to mark that buffer as done for the client and switch to the next
47 ;; Server buffer. When all the buffers for a client have been edited
48 ;; and exited with server-edit, the client "editor" will return
49 ;; to the program that invoked it.
51 ;; Your editing commands and Emacs's display output go to and from
52 ;; the terminal in the usual way. Thus, server operation is possible
53 ;; only when Emacs can talk to the terminal at the time you invoke
54 ;; the client. This is possible in four cases:
56 ;; 1. On a window system, where Emacs runs in one window and the
57 ;; program that wants to use "the editor" runs in another.
59 ;; 2. On a multi-terminal system, where Emacs runs on one terminal and the
60 ;; program that wants to use "the editor" runs on another.
62 ;; 3. When the program that wants to use "the editor" is running
63 ;; as a subprocess of Emacs.
65 ;; 4. On a system with job control, when Emacs is suspended, the program
66 ;; that wants to use "the editor" will stop and display
67 ;; "Waiting for Emacs...". It can then be suspended, and Emacs can be
68 ;; brought into the foreground for editing. When done editing, Emacs is
69 ;; suspended again, and the client program is brought into the foreground.
71 ;; The buffer local variable "server-buffer-clients" lists
72 ;; the clients who are waiting for this buffer to be edited.
73 ;; The global variable "server-clients" lists all the waiting clients,
74 ;; and which files are yet to be edited for each.
76 ;;; Code:
78 (defgroup server nil
79 "Emacs running as a server process."
80 :group 'external)
82 (defcustom server-program (expand-file-name "emacsserver" exec-directory)
83 "*The program to use as the edit server."
84 :group 'server
85 :type 'string)
87 (defcustom server-visit-hook nil
88 "*List of hooks to call when visiting a file for the Emacs server."
89 :group 'server
90 :type '(repeat function))
92 (defcustom server-switch-hook nil
93 "*List of hooks to call when switching to a buffer for the Emacs server."
94 :group 'server
95 :type '(repeat function))
97 (defcustom server-done-hook nil
98 "*List of hooks to call when done editing a buffer for the Emacs server."
99 :group 'server
100 :type '(repeat function))
102 (defvar server-process nil
103 "the current server process")
105 (defvar server-previous-string "")
107 (defvar server-clients nil
108 "List of current server clients.
109 Each element is (CLIENTID BUFFERS...) where CLIENTID is a string
110 that can be given to the server process to identify a client.
111 When a buffer is marked as \"done\", it is removed from this list.")
113 (defvar server-buffer-clients nil
114 "List of clientids for clients requesting editing of current buffer.")
115 (make-variable-buffer-local 'server-buffer-clients)
116 ;; Changing major modes should not erase this local.
117 (put 'server-buffer-clients 'permanent-local t)
119 (defvar server-window nil
120 "*The window to use for selecting Emacs server buffers.
121 If nil, use the selected window.
122 If it is a frame, use the frame's selected window.")
124 (defcustom server-temp-file-regexp "^/tmp/Re\\|/draft$"
125 "*Regexp which should match filenames of temporary files
126 which are deleted and reused after each edit
127 by the programs that invoke the emacs server."
128 :group 'server
129 :type 'regexp)
131 (or (assq 'server-buffer-clients minor-mode-alist)
132 (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
134 ;; If a *server* buffer exists,
135 ;; write STRING to it for logging purposes.
136 (defun server-log (string)
137 (if (get-buffer "*server*")
138 (save-excursion
139 (set-buffer "*server*")
140 (goto-char (point-max))
141 (insert (current-time-string) " " string)
142 (or (bolp) (newline)))))
144 (defun server-sentinel (proc msg)
145 (cond ((eq (process-status proc) 'exit)
146 (server-log (message "Server subprocess exited")))
147 ((eq (process-status proc) 'signal)
148 (server-log (message "Server subprocess killed")))))
150 ;;;###autoload
151 (defun server-start (&optional leave-dead)
152 "Allow this Emacs process to be a server for client processes.
153 This starts a server communications subprocess through which
154 client \"editors\" can send your editing commands to this Emacs job.
155 To use the server, set up the program `emacsclient' in the
156 Emacs distribution as your standard \"editor\".
158 Prefix arg means just kill any existing server communications subprocess."
159 (interactive "P")
160 ;; kill it dead!
161 (if server-process
162 (progn
163 (set-process-sentinel server-process nil)
164 (condition-case () (delete-process server-process) (error nil))))
165 ;; Delete the socket files made by previous server invocations.
166 (let* ((sysname (system-name))
167 (dot-index (string-match "\\." sysname)))
168 (condition-case ()
169 (delete-file (format "~/.emacs-server-%s" sysname))
170 (error nil))
171 (condition-case ()
172 (delete-file (format "/tmp/esrv%d-%s" (user-uid) sysname))
173 (error nil))
174 ;; In case the server file name was made with a domainless hostname,
175 ;; try deleting that name too.
176 (if dot-index
177 (let ((shortname (substring sysname 0 dot-index)))
178 (condition-case ()
179 (delete-file (format "~/.emacs-server-%s" shortname))
180 (error nil))
181 (condition-case ()
182 (delete-file (format "/tmp/esrv%d-%s" (user-uid) shortname))
183 (error nil)))))
184 ;; If this Emacs already had a server, clear out associated status.
185 (while server-clients
186 (let ((buffer (nth 1 (car server-clients))))
187 (server-buffer-done buffer)))
188 (if leave-dead
190 (if server-process
191 (server-log (message "Restarting server")))
192 ;; Using a pty is wasteful, and the separate session causes
193 ;; annoyance sometimes (some systems kill idle sessions).
194 (let ((process-connection-type nil))
195 (setq server-process (start-process "server" nil server-program)))
196 (set-process-sentinel server-process 'server-sentinel)
197 (set-process-filter server-process 'server-process-filter)
198 ;; We must receive file names without being decoded. Those are
199 ;; decoded by server-process-filter accoding to
200 ;; file-name-coding-system.
201 (set-process-coding-system server-process 'raw-text 'raw-text)
202 (process-kill-without-query server-process)))
204 ;Process a request from the server to edit some files.
205 ;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
206 (defun server-process-filter (proc string)
207 (server-log string)
208 (setq string (concat server-previous-string string))
209 ;; If the input is multiple lines,
210 ;; process each line individually.
211 (while (string-match "\n" string)
212 (let ((request (substring string 0 (match-beginning 0)))
213 (coding-system (and default-enable-multibyte-characters
214 (or file-name-coding-system
215 default-file-name-coding-system)))
216 client nowait
217 (files nil)
218 (lineno 1))
219 ;; Remove this line from STRING.
220 (setq string (substring string (match-end 0)))
221 (if (string-match "^Error: " request)
222 (message "Server error: %s" (substring request (match-end 0)))
223 (if (string-match "^Client: " request)
224 (progn
225 (setq request (substring request (match-end 0)))
226 (setq client (list (substring request 0 (string-match " " request))))
227 (setq request (substring request (match-end 0)))
228 (while (string-match "[^ ]+ " request)
229 (let ((arg
230 (substring request (match-beginning 0) (1- (match-end 0))))
231 (pos 0))
232 (setq request (substring request (match-end 0)))
233 (if (string-match "\\`-nowait" arg)
234 (setq nowait t)
235 (if (string-match "\\`\\+[0-9]+\\'" arg)
236 ;; ARG is a line number option.
237 (setq lineno (read (substring arg 1)))
238 ;; ARG is a file name.
239 ;; Collapse multiple slashes to single slashes.
240 (setq arg (command-line-normalize-file-name arg))
241 ;; Undo the quoting that emacsclient does
242 ;; for certain special characters.
243 (while (string-match "&." arg pos)
244 (setq pos (1+ (match-beginning 0)))
245 (let ((nextchar (aref arg pos)))
246 (cond ((= nextchar ?&)
247 (setq arg (replace-match "&" t t arg)))
248 ((= nextchar ?-)
249 (setq arg (replace-match "-" t t arg)))
251 (setq arg (replace-match " " t t arg))))))
252 ;; Now decode the file name if necessary.
253 (if coding-system
254 (setq arg (decode-coding-string arg coding-system)))
255 (setq files
256 (cons (list arg lineno)
257 files))
258 (setq lineno 1)))))
259 (server-visit-files files client nowait)
260 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
261 (if (null (cdr client))
262 ;; This client is empty; get rid of it immediately.
263 (progn
264 (send-string server-process
265 (format "Close: %s Done\n" (car client)))
266 (server-log (format "Close empty client: %s Done\n" (car client))))
267 ;; We visited some buffer for this client.
268 (or nowait
269 (setq server-clients (cons client server-clients)))
270 (server-switch-buffer (nth 1 client))
271 (run-hooks 'server-switch-hook)
272 (message (substitute-command-keys
273 "When done with a buffer, type \\[server-edit]"))))))))
274 ;; Save for later any partial line that remains.
275 (setq server-previous-string string))
277 (defun server-visit-files (files client &optional nowait)
278 "Finds FILES and returns the list CLIENT with the buffers nconc'd.
279 FILES is an alist whose elements are (FILENAME LINENUMBER).
280 NOWAIT non-nil means this client is not waiting for the results,
281 so don't mark these buffers specially, just visit them normally."
282 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
283 (let (client-record (last-nonmenu-event t) (obuf (current-buffer)))
284 ;; Restore the current buffer afterward, but not using save-excursion,
285 ;; because we don't want to save point in this buffer
286 ;; if it happens to be one of those specified by the server.
287 (unwind-protect
288 (while files
289 ;; If there is an existing buffer modified or the file is modified,
290 ;; revert it.
291 ;; If there is an existing buffer with deleted file, offer to write it.
292 (let* ((filen (car (car files)))
293 (obuf (get-file-buffer filen)))
294 (if (and obuf (set-buffer obuf))
295 (if (file-exists-p filen)
296 (if (or (not (verify-visited-file-modtime obuf))
297 (buffer-modified-p obuf))
298 (revert-buffer t nil))
299 (if (y-or-n-p
300 (concat "File no longer exists: "
301 filen
302 ", write buffer to file? "))
303 (write-file filen)))
304 (set-buffer (find-file-noselect filen))
305 (run-hooks 'server-visit-hook)))
306 (goto-line (nth 1 (car files)))
307 (if (not nowait)
308 (setq server-buffer-clients
309 (cons (car client) server-buffer-clients)))
310 (setq client-record (cons (current-buffer) client-record))
311 (setq files (cdr files)))
312 (set-buffer obuf))
313 (nconc client client-record)))
315 (defun server-buffer-done (buffer &optional for-killing)
316 "Mark BUFFER as \"done\" for its client(s).
317 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
318 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
319 or nil. KILLED is t if we killed BUFFER
320 \(typically, because it was visiting a temp file)."
321 (let ((running (eq (process-status server-process) 'run))
322 (next-buffer nil)
323 (killed nil)
324 (first t)
325 (old-clients server-clients))
326 (while old-clients
327 (let ((client (car old-clients)))
328 (or next-buffer
329 (setq next-buffer (nth 1 (memq buffer client))))
330 (delq buffer client)
331 ;; Delete all dead buffers from CLIENT.
332 (let ((tail client))
333 (while tail
334 (and (bufferp (car tail))
335 (null (buffer-name (car tail)))
336 (delq (car tail) client))
337 (setq tail (cdr tail))))
338 ;; If client now has no pending buffers,
339 ;; tell it that it is done, and forget it entirely.
340 (if (cdr client) nil
341 (if running
342 (progn
343 ;; Don't send emacsserver two commands in close succession.
344 ;; It cannot handle that.
345 (or first (sit-for 1))
346 (setq first nil)
347 (send-string server-process
348 (format "Close: %s Done\n" (car client)))
349 (server-log (format "Close: %s Done\n" (car client)))))
350 (setq server-clients (delq client server-clients))))
351 (setq old-clients (cdr old-clients)))
352 (if (and (bufferp buffer) (buffer-name buffer))
353 ;; We may or may not kill this buffer;
354 ;; if we do, do not call server-buffer-done recursively
355 ;; from kill-buffer-hook.
356 (let ((server-kill-buffer-running t))
357 (save-excursion
358 (set-buffer buffer)
359 (setq server-buffer-clients nil)
360 (run-hooks 'server-done-hook))
361 ;; Notice whether server-done-hook killed the buffer.
362 (if (null (buffer-name buffer))
363 (setq killed t)
364 ;; Don't bother killing or burying the buffer
365 ;; when we are called from kill-buffer.
366 (unless for-killing
367 (if (server-temp-file-p buffer)
368 (progn (kill-buffer buffer)
369 (setq killed t))
370 (bury-buffer buffer))))))
371 (list next-buffer killed)))
373 (defun server-temp-file-p (buffer)
374 "Return non-nil if BUFFER contains a file considered temporary.
375 These are files whose names suggest they are repeatedly
376 reused to pass information to another program.
378 The variable `server-temp-file-regexp' controls which filenames
379 are considered temporary."
380 (and (buffer-file-name buffer)
381 (string-match server-temp-file-regexp (buffer-file-name buffer))))
383 (defun server-done ()
384 "Offer to save current buffer, mark it as \"done\" for clients.
385 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
386 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
387 or nil. KILLED is t if we killed BUFFER
388 \(typically, because it was visiting a temp file)."
389 (let ((buffer (current-buffer)))
390 (if server-buffer-clients
391 (progn
392 (if (server-temp-file-p buffer)
393 ;; For a temp file, save, and do make a non-numeric backup
394 ;; (unless make-backup-files is nil).
395 (let ((version-control nil)
396 (buffer-backed-up nil))
397 (save-buffer))
398 (if (and (buffer-modified-p)
399 buffer-file-name
400 (y-or-n-p (concat "Save file " buffer-file-name "? ")))
401 (save-buffer buffer)))
402 (server-buffer-done buffer)))))
404 ;; Ask before killing a server buffer.
405 ;; It was suggested to release its client instead,
406 ;; but I think that is dangerous--the client would proceed
407 ;; using whatever is on disk in that file. -- rms.
408 (defun server-kill-buffer-query-function ()
409 (or (not server-buffer-clients)
410 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
411 (buffer-name (current-buffer))))))
413 (add-hook 'kill-buffer-query-functions
414 'server-kill-buffer-query-function)
416 (defun server-kill-emacs-query-function ()
417 (let (live-client
418 (tail server-clients))
419 ;; See if any clients have any buffers that are still alive.
420 (while tail
421 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
422 (setq live-client t))
423 (setq tail (cdr tail)))
424 (or (not live-client)
425 (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
427 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
429 (defvar server-kill-buffer-running nil
430 "Non-nil while `server-kill-buffer' or `server-buffer-done' is running.")
432 ;; When a buffer is killed, inform the clients.
433 (add-hook 'kill-buffer-hook 'server-kill-buffer)
434 (defun server-kill-buffer ()
435 ;; Prevent infinite recursion if user has made server-done-hook
436 ;; call kill-buffer.
437 (or server-kill-buffer-running
438 (and server-buffer-clients
439 (let ((server-kill-buffer-running t))
440 (when server-process
441 (server-buffer-done (current-buffer) t))))))
443 (defun server-edit (&optional arg)
444 "Switch to next server editing buffer; say \"Done\" for current buffer.
445 If a server buffer is current, it is marked \"done\" and optionally saved.
446 When all of a client's buffers are marked as \"done\", the client is notified.
448 Temporary files such as MH <draft> files are always saved and backed up,
449 no questions asked. (The variable `make-backup-files', if nil, still
450 inhibits a backup; you can set it locally in a particular buffer to
451 prevent a backup for it.) The variable `server-temp-file-regexp' controls
452 which filenames are considered temporary.
454 If invoked with a prefix argument, or if there is no server process running,
455 starts server process and that is all. Invoked by \\[server-edit]."
456 (interactive "P")
457 (if (or arg
458 (not server-process)
459 (memq (process-status server-process) '(signal exit)))
460 (server-start nil)
461 (apply 'server-switch-buffer (server-done))))
463 (defun server-switch-buffer (&optional next-buffer killed-one)
464 "Switch to another buffer, preferably one that has a client.
465 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
466 ;; KILLED-ONE is t in a recursive call
467 ;; if we have already killed one temp-file server buffer.
468 ;; This means we should avoid the final "switch to some other buffer"
469 ;; since we've already effectively done that.
470 (cond ((and (windowp server-window)
471 (window-live-p server-window))
472 (select-window server-window))
473 ((framep server-window)
474 (if (not (frame-live-p server-window))
475 (setq server-window (make-frame)))
476 (select-window (frame-selected-window server-window))))
477 (if (window-minibuffer-p (selected-window))
478 (select-window (next-window nil 'nomini 0)))
479 ;; Move to a non-dedicated window, if we have one.
480 (let ((last-window (previous-window nil 'nomini 0)))
481 (while (and (window-dedicated-p (selected-window))
482 (not (eq last-window (selected-window))))
483 (select-window (next-window nil 'nomini 0))))
484 (set-window-dedicated-p (selected-window) nil)
485 (if next-buffer
486 (if (and (bufferp next-buffer)
487 (buffer-name next-buffer))
488 (switch-to-buffer next-buffer)
489 ;; If NEXT-BUFFER is a dead buffer,
490 ;; remove the server records for it
491 ;; and try the next surviving server buffer.
492 (apply 'server-switch-buffer
493 (server-buffer-done next-buffer)))
494 (if server-clients
495 (server-switch-buffer (nth 1 (car server-clients)) killed-one)
496 (if (not killed-one)
497 (switch-to-buffer (other-buffer))))))
499 (global-set-key "\C-x#" 'server-edit)
501 (provide 'server)
503 ;;; server.el ends here