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1 ;;; server.el --- Lisp code for GNU Emacs running as server process
3 ;; Copyright (C) 1986, 1987, 1992, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4 ;; 2001, 2002, 2003, 2004, 2005 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., 51 Franklin Street, Fifth Floor,
27 ;; Boston, MA 02110-1301, 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 opens up a socket for communication with clients. If there are no
36 ;; client buffers to edit, server-edit acts like (switch-to-buffer
37 ;; (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:
82 "Emacs running as a server process."
86 "*Hook run when visiting a file for the Emacs server."
91 "*Hook run when switching to a buffer for the Emacs server."
96 "*Hook run when done editing a buffer for the Emacs server."
104 "List of current server clients.
105 Each element is (CLIENTID BUFFERS...) where CLIENTID is a string
106 that can be given to the server process to identify a client.
112 ;; Changing major modes should not erase this local.
116 "*Specification of the window to use for selecting Emacs server buffers.
117 If nil, use the selected window.
118 If it is a function, it should take one argument (a buffer) and
119 display and select it. A common value is `pop-to-buffer'.
120 If it is a window, use that.
121 If it is a frame, use the frame's selected window.
123 It is not meaningful to set this to a specific frame or window with Custom.
124 Only programs can do so."
130 nil)
135 "*Regexp matching names of temporary files.
136 These are deleted and reused after each edit by the programs that
137 invoke the Emacs server."
142 "*Whether to kill buffers when done with them.
143 If non-nil, kill a buffer unless it already existed before editing
144 it with Emacs server. If nil, kill only buffers as specified by
145 `server-temp-file-regexp'.
146 Please note that only buffers are killed that still have a client,
148 this way."
157 "Non-nil means the buffer existed before the server was asked to visit it.
158 This means that the server should not kill the buffer when you say you
168 "If a *server* buffer exists, write STRING to it for logging purposes."
174 string)
179 ;; Remove PROC from the list of clients.
184 ;; Remove PROC from the clients of each buffer.
186 ;; Kill the buffer if necessary.
192 ;; If this is a new client process, set the query-on-exit flag to nil
193 ;; for this process (it isn't inherited from the server process).
200 ;; If the current frame is on `display' we're all set.
202 ;; Otherwise, look for an existing frame there and select it.
206 ;; If there's no frame on that display yet, create a dummy one
207 ;; and select it.
211 display
212 ;; This frame is only there in place of an actual "current display"
213 ;; setting, so we want it to be as unobtrusive as possible. That's
214 ;; what the invisibility is for. The minibuffer setting is so that
215 ;; we don't end up displaying a buffer in it (which noone would
216 ;; notice).
227 arg t t))
230 "Make sure DIR is a directory with no race-condition issues.
231 Creates the directory if necessary and makes sure:
232 - there's no symlink involved
233 - it's owned by us
234 - it's not readable/writable by anybody else."
240 ;; Check that it's safe for use.
245 ;;;###autoload
247 "Allow this Emacs process to be a server for client processes.
248 This starts a server communications subprocess through which
250 To use the server, set up the program `emacsclient' in the
253 Prefix arg means just kill any existing server communications subprocess."
255 ;; Make sure there is a safe directory in which to place the socket.
257 ;; kill it dead!
260 ;; Delete the socket files made by previous server invocations.
264 ;; If this Emacs already had a server, clear out associated status.
277 ;; We must receive file names without being decoded.
278 ;; Those are decoded by server-process-filter according
279 ;; to file-name-coding-system.
282 ;;;###autoload
284 "Toggle Server mode.
285 With ARG, turn Server mode on if ARG is positive, off otherwise.
286 Server mode runs a process that accepts commands from the
287 `emacsclient' program. See `server-start' and Info node `Emacs server'."
288 :global t
291 ;; Fixme: Should this check for an existing server socket and do
292 ;; nothing if there is one (for multiple Emacs sessions)?
294 \f
296 "Process a request from the server to edit some files.
303 ;; If the input is multiple lines,
304 ;; process each line individually.
309 default-file-name-coding-system)))
310 client nowait eval
315 ;; Remove this line from STRING.
331 ;; ARG is a line number option.
334 ;; ARG is line number:column option.
339 ;; Undo the quoting that emacsclient does
340 ;; for certain special characters.
342 ;; Now decode the file name if necessary.
351 ;; Suppress the error rose when the pipe to PROC is closed.
356 ))))
357 ;; ARG is a file name.
358 ;; Collapse multiple slashes to single slashes.
367 ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
369 ;; This client is empty; get rid of it immediately.
373 ;; We visited some buffer for this client.
381 ;; Avoid preserving the connection after the last real frame is deleted.
383 ;; Save for later any partial line that remains.
394 "Find FILES and return the list CLIENT with the buffers nconc'd.
395 FILES is an alist whose elements are (FILENAME LINENUMBER COLUMNNUMBER).
396 NOWAIT non-nil means this client is not waiting for the results,
397 so don't mark these buffers specially, just visit them normally."
398 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
400 ;; Restore the current buffer afterward, but not using save-excursion,
401 ;; because we don't want to save point in this buffer
402 ;; if it happens to be one of those specified by the server.
405 ;; If there is an existing buffer modified or the file is
406 ;; modified, revert it. If there is an existing buffer with
407 ;; deleted file, offer to write it.
419 filen
428 ;; When the buffer is killed, inform the clients.
433 \f
436 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
437 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
438 or nil. KILLED is t if we killed BUFFER (typically, because it was visiting
439 a temp file).
440 FOR-KILLING if non-nil indicates that we are called from `kill-buffer'."
449 ;; Delete all dead buffers from CLIENT.
456 ;; If client now has no pending buffers,
457 ;; tell it that it is done, and forget it entirely.
464 ;; We may or may not kill this buffer;
465 ;; if we do, do not call server-buffer-done recursively
466 ;; from kill-buffer-hook.
471 ;; Notice whether server-done-hook killed the buffer.
474 ;; Don't bother killing or burying the buffer
475 ;; when we are called from kill-buffer.
478 server-kill-new-buffers
493 "Return non-nil if BUFFER contains a file considered temporary.
494 These are files whose names suggest they are repeatedly
495 reused to pass information to another program.
497 The variable `server-temp-file-regexp' controls which filenames
498 are considered temporary."
504 This kills or buries the buffer, then returns a list
505 of the form (NEXT-BUFFER KILLED). NEXT-BUFFER is another server buffer,
506 as a suggestion for what to select next, or nil.
507 KILLED is t if we killed BUFFER, which happens if it was created
508 specifically for the clients and did not exist before their request for it."
511 ;; For a temp file, save, and do make a non-numeric backup
512 ;; (unless make-backup-files is nil).
517 buffer-file-name
522 ;; Ask before killing a server buffer.
523 ;; It was suggested to release its client instead,
524 ;; but I think that is dangerous--the client would proceed
525 ;; using whatever is on disk in that file. -- rms.
537 ;; See if any clients have any buffers that are still alive.
551 ;; Prevent infinite recursion if user has made server-done-hook
552 ;; call kill-buffer.
558 \f
562 The buffer is also killed if it did not exist before the clients asked for it.
565 Temporary files such as MH <draft> files are always saved and backed up,
566 no questions asked. (The variable `make-backup-files', if nil, still
567 inhibits a backup; you can set it locally in a particular buffer to
568 prevent a backup for it.) The variable `server-temp-file-regexp' controls
569 which filenames are considered temporary.
571 If invoked with a prefix argument, or if there is no server process running,
581 "Switch to another buffer, preferably one that has a client.
582 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
583 ;; KILLED-ONE is t in a recursive call
584 ;; if we have already killed one temp-file server buffer.
585 ;; This means we should avoid the final "switch to some other buffer"
586 ;; since we've already effectively done that.
594 ;; If NEXT-BUFFER is a dead buffer, remove the server records for it
595 ;; and try the next surviving server buffer.
597 ;; OK, we know next-buffer is live, let's display and select it.
602 ;; The buffer is already displayed: just reuse the window.
608 ;; Otherwise, let's find an appropriate window.
618 ;; Move to a non-dedicated window, if we have one.
629 ;; After all the above, we might still have ended up with
630 ;; a minibuffer/dedicated-window (if there's no other).
642 \f
645 ;;; arch-tag: 1f7ecb42-f00a-49f8-906d-61995d84c8d6
646 ;;; server.el ends here