comparison lisp/packages/server.el @ 0:376386a54a3c r19-14

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date Mon, 13 Aug 2007 08:45:50 +0200
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1 ;;; server.el --- Lisp code for GNU Emacs running as server process.
2
3 ;; Copyright (C) 1986, 1987, 1992, 1994, 1995 Free Software Foundation, Inc.
4
5 ;; Author: William Sommerfeld <wesommer@athena.mit.edu>
6 ;; Keywords: processes
7
8 ;; Changes by peck@sun.com and by rms.
9
10 ;; This file is part of XEmacs.
11
12 ;; XEmacs is free software; you can redistribute it and/or modify it
13 ;; under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; any later version.
16
17 ;; XEmacs is distributed in the hope that it will be useful, but
18 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 ;; General Public License for more details.
21
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with XEmacs; see the file COPYING. If not, write to the Free
24 ;; Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
25
26 ;;; Synched up with FSF 19.30.
27
28 ;;; Commentary:
29
30 ;;; This Lisp code is run in Emacs when it is to operate as
31 ;;; a server for other processes.
32
33 ;;; Load this library and do M-x server-edit to enable Emacs as a server.
34 ;;; Emacs runs the program ../etc/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))
37
38 ;;; When some other program runs "the editor" to edit a file,
39 ;;; "the editor" can be the Emacs client program ../etc/emacsclient.
40 ;;; This program transmits the file names to Emacs through
41 ;;; the server subprocess, and Emacs visits them and lets you edit them.
42
43 ;;; Note that any number of clients may dispatch files to emacs to be edited.
44
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.
50
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:
55
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.
58
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.
61
62 ;;; 3. When the program that wants to use "the editor" is running
63 ;;; as a subprocess of Emacs.
64
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.
70
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.
75
76 ;;; Code:
77
78 (defvar server-program (expand-file-name "emacsserver" exec-directory)
79 "*The program to use as the edit server.")
80
81 (defvar server-visit-hook nil
82 "*List of hooks to call when visiting a file for the Emacs server.")
83
84 (defvar server-switch-hook nil
85 "*List of hooks to call when switching to a buffer for the Emacs server.")
86
87 (defvar server-done-hook nil
88 "*List of hooks to call when done editing a buffer for the Emacs server.")
89
90 (defvar server-process nil
91 "the current server process")
92
93 (defvar server-previous-string "")
94
95 (defvar server-clients nil
96 "List of current server clients.
97 Each element is (CLIENTID BUFFERS...) where CLIENTID is a string
98 that can be given to the server process to identify a client.
99 When a buffer is marked as \"done\", it is removed from this list.")
100
101 (defvar server-buffer-clients nil
102 "List of clientids for clients requesting editing of current buffer.")
103 (make-variable-buffer-local 'server-buffer-clients)
104 ;; Changing major modes should not erase this local.
105 (put 'server-buffer-clients 'permanent-local t)
106
107 (defvar server-window nil
108 "*The window to use for selecting Emacs server buffers.
109 If nil, use the selected window.
110 If it is a frame, use the frame's selected window.")
111
112 (defvar server-temp-file-regexp "^/tmp/Re\\|/draft$"
113 "*Regexp which should match filenames of temporary files
114 which are deleted and reused after each edit
115 by the programs that invoke the emacs server.")
116
117 (or (assq 'server-buffer-clients minor-mode-alist)
118 (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
119
120 ;; If a *server* buffer exists,
121 ;; write STRING to it for logging purposes.
122 (defun server-log (string)
123 (if (get-buffer "*server*")
124 (save-excursion
125 (set-buffer "*server*")
126 (goto-char (point-max))
127 (insert (current-time-string) " " string)
128 (or (bolp) (newline)))))
129
130 (defun server-sentinel (proc msg)
131 (cond ((eq (process-status proc) 'exit)
132 (server-log (message "Server subprocess exited")))
133 ((eq (process-status proc) 'signal)
134 (server-log (message "Server subprocess killed")))))
135
136 ;;;###autoload
137 (make-obsolete 'server-start 'gnuserv-start)
138 (defun server-start (&optional leave-dead)
139 "Use `gnuserv-start' instead of this function.
140 Allow this Emacs process to be a server for client processes.
141 This starts a server communications subprocess through which
142 client \"editors\" can send your editing commands to this Emacs job.
143 To use the server, set up the program `emacsclient' in the
144 Emacs distribution as your standard \"editor\".
145
146 Prefix arg means just kill any existing server communications subprocess."
147 (interactive "P")
148 ;; kill it dead!
149 (if server-process
150 (progn
151 (set-process-sentinel server-process nil)
152 (condition-case () (delete-process server-process) (error nil))))
153 (condition-case () (delete-file "~/.emacs_server") (error nil))
154 (let* ((sysname (system-name))
155 (dot-index (string-match "\\." sysname)))
156 (condition-case ()
157 (delete-file (format "/tmp/esrv%d-%s" (user-uid) sysname))
158 (error nil))
159 ;; In case the server file name was made with a domainless hostname,
160 ;; try deleting that name too.
161 (if dot-index
162 (condition-case ()
163 (delete-file (format "/tmp/esrv%d-%s" (user-uid)
164 (substring sysname 0 dot-index)))
165 (error nil))))
166 ;; If we already had a server, clear out associated status.
167 (while server-clients
168 (let ((buffer (nth 1 (car server-clients))))
169 (server-buffer-done buffer)))
170 (if leave-dead
171 nil
172 (if server-process
173 (server-log (message "Restarting server")))
174 ;; Using a pty is wasteful, and the separate session causes
175 ;; annoyance sometimes (some systems kill idle sessions).
176 (let ((process-connection-type nil))
177 (setq server-process (start-process "server" nil server-program)))
178 (set-process-sentinel server-process 'server-sentinel)
179 (set-process-filter server-process 'server-process-filter)
180 (process-kill-without-query server-process)))
181
182 ;Process a request from the server to edit some files.
183 ;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
184 (defun server-process-filter (proc string)
185 (server-log string)
186 (setq string (concat server-previous-string string))
187 ;; If the input is multiple lines,
188 ;; process each line individually.
189 (while (string-match "\n" string)
190 (let ((request (substring string 0 (match-beginning 0)))
191 client
192 (files nil)
193 (lineno 1))
194 ;; Remove this line from STRING.
195 (setq string (substring string (match-end 0)))
196 (if (string-match "^Error: " request)
197 (message (concat "Server error: " (substring request (match-end 0))))
198 (if (string-match "^Client: " request)
199 (progn
200 (setq request (substring request (match-end 0)))
201 (setq client (list (substring request 0 (string-match " " request))))
202 (setq request (substring request (match-end 0)))
203 (while (string-match "[^ ]+ " request)
204 (let ((arg
205 (substring request (match-beginning 0) (1- (match-end 0)))))
206 (setq request (substring request (match-end 0)))
207 (if (string-match "\\`\\+[0-9]+\\'" arg)
208 (setq lineno (read (substring arg 1)))
209 (setq files
210 (cons (list arg lineno)
211 files))
212 (setq lineno 1))))
213 (server-visit-files files client)
214 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
215 (setq server-clients (cons client server-clients))
216 (server-switch-buffer (nth 1 client))
217 (run-hooks 'server-switch-hook)
218 (message (substitute-command-keys
219 "When done with a buffer, type \\[server-edit]")))))))
220 ;; Save for later any partial line that remains.
221 (setq server-previous-string string))
222
223 (defun server-visit-files (files client)
224 "Finds FILES and returns the list CLIENT with the buffers nconc'd.
225 FILES is an alist whose elements are (FILENAME LINENUMBER)."
226 (let (client-record (obuf (current-buffer)))
227 ;; Restore the current buffer afterward, but not using save-excursion,
228 ;; because we don't want to save point in this buffer
229 ;; if it happens to be one of those specified by the server.
230 (unwind-protect
231 (while files
232 ;; If there is an existing buffer modified or the file is modified,
233 ;; revert it.
234 ;; If there is an existing buffer with deleted file, offer to write it.
235 (let* ((filen (car (car files)))
236 (obuf (get-file-buffer filen)))
237 (if (and obuf (set-buffer obuf))
238 (if (file-exists-p filen)
239 (if (or (not (verify-visited-file-modtime obuf))
240 (buffer-modified-p obuf))
241 (revert-buffer t nil))
242 (if (y-or-n-p
243 (concat "File no longer exists: "
244 filen
245 ", write buffer to file? "))
246 (write-file filen)))
247 (set-buffer (find-file-noselect filen))
248 (run-hooks 'server-visit-hook)))
249 (goto-line (nth 1 (car files)))
250 (setq server-buffer-clients (cons (car client) server-buffer-clients))
251 (setq client-record (cons (current-buffer) client-record))
252 (setq files (cdr files)))
253 (set-buffer obuf))
254 (nconc client client-record)))
255
256 (defun server-buffer-done (buffer)
257 "Mark BUFFER as \"done\" for its client(s).
258 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
259 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
260 or nil. KILLED is t if we killed BUFFER (because it was a temp file)."
261 (let ((running (eq (process-status server-process) 'run))
262 (next-buffer nil)
263 (killed nil)
264 (first t)
265 (old-clients server-clients))
266 (while old-clients
267 (let ((client (car old-clients)))
268 (or next-buffer
269 (setq next-buffer (nth 1 (memq buffer client))))
270 (delq buffer client)
271 ;; Delete all dead buffers from CLIENT.
272 (let ((tail client))
273 (while tail
274 (and (bufferp (car tail))
275 (null (buffer-name (car tail)))
276 (delq (car tail) client))
277 (setq tail (cdr tail))))
278 ;; If client now has no pending buffers,
279 ;; tell it that it is done, and forget it entirely.
280 (if (cdr client) nil
281 (if running
282 (progn
283 ;; Don't send emacsserver two commands in close succession.
284 ;; It cannot handle that.
285 (or first (sit-for 1))
286 (setq first nil)
287 (process-send-string server-process
288 (format "Close: %s Done\n" (car client)))
289 (server-log (format "Close: %s Done\n" (car client)))))
290 (setq server-clients (delq client server-clients))))
291 (setq old-clients (cdr old-clients)))
292 (if (and (bufferp buffer) (buffer-name buffer))
293 (progn
294 (save-excursion
295 (set-buffer buffer)
296 (setq server-buffer-clients nil)
297 (run-hooks 'server-done-hook))
298 (if (server-temp-file-p buffer)
299 (progn (kill-buffer buffer)
300 (setq killed t))
301 (bury-buffer buffer))))
302 (list next-buffer killed)))
303
304 (defun server-temp-file-p (buffer)
305 "Return non-nil if BUFFER contains a file considered temporary.
306 These are files whose names suggest they are repeatedly
307 reused to pass information to another program.
308
309 The variable `server-temp-file-regexp' controls which filenames
310 are considered temporary."
311 (and (buffer-file-name buffer)
312 (string-match server-temp-file-regexp (buffer-file-name buffer))))
313
314 (defun server-done ()
315 "Offer to save current buffer, mark it as \"done\" for clients.
316 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
317 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
318 or nil. KILLED is t if we killed the BUFFER (because it was a temp file)."
319 (let ((buffer (current-buffer)))
320 (if server-buffer-clients
321 (progn
322 (if (server-temp-file-p buffer)
323 ;; For a temp file, save, and do make a non-numeric backup
324 ;; (unless make-backup-files is nil).
325 (let ((version-control nil)
326 (buffer-backed-up nil))
327 (save-buffer))
328 (if (and (buffer-modified-p)
329 (y-or-n-p (concat "Save file " buffer-file-name "? ")))
330 (save-buffer buffer)))
331 (server-buffer-done buffer)))))
332
333 ;; Ask before killing a server buffer.
334 ;; It was suggested to release its client instead,
335 ;; but I think that is dangerous--the client would proceed
336 ;; using whatever is on disk in that file. -- rms.
337 (defun server-kill-buffer-query-function ()
338 (or (not server-buffer-clients)
339 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
340 (buffer-name (current-buffer))))))
341
342 (add-hook 'kill-buffer-query-functions
343 'server-kill-buffer-query-function)
344
345 (defun server-kill-emacs-query-function ()
346 (let (live-client
347 (tail server-clients))
348 ;; See if any clients have any buffers that are still alive.
349 (while tail
350 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
351 (setq live-client t))
352 (setq tail (cdr tail)))
353 (or (not live-client)
354 (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
355
356 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
357
358 (defun server-edit (&optional arg)
359 "Switch to next server editing buffer; say \"Done\" for current buffer.
360 If a server buffer is current, it is marked \"done\" and optionally saved.
361 When all of a client's buffers are marked as \"done\", the client is notified.
362
363 Temporary files such as MH <draft> files are always saved and backed up,
364 no questions asked. (The variable `make-backup-files', if nil, still
365 inhibits a backup; you can set it locally in a particular buffer to
366 prevent a backup for it.) The variable `server-temp-file-regexp' controls
367 which filenames are considered temporary.
368
369 If invoked with a prefix argument, or if there is no server process running,
370 starts server process and that is all. Invoked by \\[server-edit]."
371 (interactive "P")
372 (if (or arg
373 (not server-process)
374 (memq (process-status server-process) '(signal exit)))
375 (server-start nil)
376 (apply 'server-switch-buffer (server-done))))
377
378 (defun server-switch-buffer (&optional next-buffer killed-one)
379 "Switch to another buffer, preferably one that has a client.
380 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
381 ;; KILLED-ONE is t in a recursive call
382 ;; if we have already killed one temp-file server buffer.
383 ;; This means we should avoid the final "switch to some other buffer"
384 ;; since we've already effectively done that.
385 (cond ((and (windowp server-window)
386 (window-live-p server-window))
387 (select-window server-window))
388 ((framep server-window)
389 (if (not (frame-live-p server-window))
390 (setq server-window (make-frame)))
391 (select-window (frame-selected-window server-window))))
392 (if (window-minibuffer-p (selected-window))
393 (select-window (next-window nil 'nomini 0)))
394 ;; Move to a non-dedicated window, if we have one.
395 (let ((last-window (previous-window nil 'nomini 0)))
396 (while (and (window-dedicated-p (selected-window))
397 (not (eq last-window (selected-window))))
398 (select-window (next-window nil 'nomini 0))))
399 (set-window-dedicated-p (selected-window) nil)
400 (if next-buffer
401 (if (and (bufferp next-buffer)
402 (buffer-name next-buffer))
403 (switch-to-buffer next-buffer)
404 ;; If NEXT-BUFFER is a dead buffer,
405 ;; remove the server records for it
406 ;; and try the next surviving server buffer.
407 (apply 'server-switch-buffer
408 (server-buffer-done next-buffer)))
409 (if server-clients
410 (server-switch-buffer (nth 1 (car server-clients)) killed-one)
411 (if (not killed-one)
412 (switch-to-buffer (other-buffer))))))
413
414 (global-set-key "\C-x#" 'server-edit)
415
416 (provide 'server)
417
418 ;;; server.el ends here