lisp/server.el

   1 ;;; server.el --- Lisp code for GNU Emacs running as server process
   2
   3 ;; Copyright (C) 1986,87,92,94,95,96,97,98,99,2000,01,02,2003
   4 ;;       Free Software Foundation, Inc.
   5
   6 ;; Author: William Sommerfeld <wesommer@athena.mit.edu>
   7 ;; Maintainer: FSF
   8 ;; Keywords: processes
   9
  10 ;; Changes by peck@sun.com and by rms.
  11
  12 ;; This file is part of GNU Emacs.
  13
  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.
  18
  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.
  23
  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.
  28
  29 ;;; Commentary:
  30
  31 ;; This Lisp code is run in Emacs when it is to operate as
  32 ;; a server for other processes.
  33
  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))
  38
  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.
  43
  44 ;; Note that any number of clients may dispatch files to emacs to be edited.
  45
  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.
  51
  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:
  56
  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.
  59
  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.
  62
  63 ;; 3. When the program that wants to use "the editor" is running
  64 ;; as a subprocess of Emacs.
  65
  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.
  71
  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.
  76
  77 ;;; Code:
  78
  79 (eval-when-compile (require 'cl))
  80
  81 (defgroup server nil
  82   "Emacs running as a server process."
  83   :group 'external)
  84
  85 (defcustom server-visit-hook nil
  86   "*Hook run when visiting a file for the Emacs server."
  87   :group 'server
  88   :type 'hook)
  89
  90 (defcustom server-switch-hook nil
  91   "*Hook run when switching to a buffer for the Emacs server."
  92   :group 'server
  93   :type 'hook)
  94
  95 (defcustom server-done-hook nil
  96   "*Hook run when done editing a buffer for the Emacs server."
  97   :group 'server
  98   :type 'hook)
  99
 100 (defvar server-process nil
 101   "The current server process.")
 102
 103 (defvar server-clients nil
 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.
 107 When a buffer is marked as \"done\", it is removed from this list.")
 108
 109 (defvar server-frames nil
 110   "List of current server frames.
 111 Each element is (CLIENTID FRAME) where CLIENTID is a string
 112 that can be given to the server process to identify a client.
 113 When all the buffers of the client are marked as \"done\",
 114 the frame is deleted.")
 115
 116 (defvar server-buffer-clients nil
 117   "List of client ids for clients requesting editing of current buffer.")
 118 (make-variable-buffer-local 'server-buffer-clients)
 119 ;; Changing major modes should not erase this local.
 120 (put 'server-buffer-clients 'permanent-local t)
 121
 122 (defcustom server-window nil
 123   "*Specification of the window to use for selecting Emacs server buffers.
 124 If nil, use the selected window.
 125 If it is a function, it should take one argument (a buffer) and
 126 display and select it.  A common value is `pop-to-buffer'.
 127 If it is a window, use that.
 128 If it is a frame, use the frame's selected window.
 129
 130 It is not meaningful to set this to a specific frame or window with Custom.
 131 Only programs can do so."
 132   :group 'server
 133   :version "21.4"
 134   :type '(choice (const :tag "Use selected window"
 135                         :match (lambda (widget value)
 136                                  (not (functionp value)))
 137                         nil)
 138                  (function-item :tag "Use pop-to-buffer" pop-to-buffer)
 139                  (function :tag "Other function")))
 140
 141 (defcustom server-temp-file-regexp "^/tmp/Re\\|/draft$"
 142   "*Regexp matching names of temporary files.
 143 These are deleted and reused after each edit by the programs that
 144 invoke the Emacs server."
 145   :group 'server
 146   :type 'regexp)
 147
 148 (defcustom server-kill-new-buffers t
 149   "*Whether to kill buffers when done with them.
 150 If non-nil, kill a buffer unless it already existed before editing
 151 it with Emacs server.  If nil, kill only buffers as specified by
 152 `server-temp-file-regexp'.
 153 Please note that only buffers are killed that still have a client,
 154 i.e. buffers visited which \"emacsclient --no-wait\" are never killed in
 155 this way."
 156   :group 'server
 157   :type 'boolean
 158   :version "21.1")
 159
 160 (or (assq 'server-buffer-clients minor-mode-alist)
 161     (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
 162
 163 (defvar server-existing-buffer nil
 164   "Non-nil means the buffer existed before the server was asked to visit it.
 165 This means that the server should not kill the buffer when you say you
 166 are done with it in the server.")
 167 (make-variable-buffer-local 'server-existing-buffer)
 168
 169 (defvar server-socket-name
 170   (format "/tmp/emacs%d-%s/server" (user-uid)
 171           (substring (system-name) 0 (string-match "\\." (system-name)))))
 172
 173 (defun server-log (string &optional client)
 174   "If a *server* buffer exists, write STRING to it for logging purposes."
 175   (if (get-buffer "*server*")
 176       (with-current-buffer "*server*"
 177         (goto-char (point-max))
 178         (insert (current-time-string)
 179                 (if client (format " %s:" client) " ")
 180                 string)
 181         (or (bolp) (newline)))))
 182
 183 (defun server-sentinel (proc msg)
 184   (let ((client (assq proc server-clients)))
 185     ;; Remove PROC from the list of clients.
 186     (when client
 187       (setq server-clients (delq client server-clients))
 188       (setq server-frames (delq client server-frames))
 189       (dolist (buf (cdr client))
 190         (with-current-buffer buf
 191           ;; Remove PROC from the clients of each buffer.
 192           (setq server-buffer-clients (delq proc server-buffer-clients))
 193           ;; Kill the buffer if necessary.
 194           (when (and (null server-buffer-clients)
 195                      (or (and server-kill-new-buffers
 196                               (not server-existing-buffer))
 197                          (server-temp-file-p)))
 198             (kill-buffer (current-buffer)))))))
 199   (server-log (format "Status changed to %s" (process-status proc)) proc))
 200
 201 (defun server-select-display (display)
 202   ;; If the current frame is on `display' we're all set.
 203   (unless (equal (frame-parameter (selected-frame) 'display) display)
 204     ;; Otherwise, look for an existing frame there and select it.
 205     (dolist (frame (frame-list))
 206       (when (equal (frame-parameter frame 'display) display)
 207         (select-frame frame)))
 208     ;; If there's no frame on that display yet, create a dummy one
 209     ;; and select it.
 210     (unless (equal (frame-parameter (selected-frame) 'display) display)
 211       (select-frame
 212        (make-frame-on-display
 213         display
 214         ;; This frame is only there in place of an actual "current display"
 215         ;; setting, so we want it to be as unobtrusive as possible.  That's
 216         ;; what the invisibility is for.  The minibuffer setting is so that
 217         ;; we don't end up displaying a buffer in it (which noone would
 218         ;; notice).
 219         '((visibility . nil) (minibuffer . only)))))))
 220
 221 (defun server-unquote-arg (arg)
 222   (replace-regexp-in-string
 223    "&." (lambda (s)
 224           (case (aref s 1)
 225             (?& "&")
 226             (?- "-")
 227             (?n "\n")
 228             (t " ")))
 229    arg t t))
 230
 231 (defun server-ensure-safe-dir (dir)
 232   "Make sure DIR is a directory with no race-condition issues.
 233 Creates the directory if necessary and makes sure:
 234 - there's no symlink involved
 235 - it's owned by us
 236 - it's not readable/writable by anybody else."
 237   (setq dir (directory-file-name dir))
 238   (let ((attrs (file-attributes dir)))
 239     (unless attrs
 240       (letf (((default-file-modes) ?\700)) (make-directory dir))
 241       (setq attrs (file-attributes dir)))
 242     ;; Check that it's safe for use.
 243     (unless (and (eq t (car attrs)) (eq (nth 2 attrs) (user-uid))
 244                  (zerop (logand ?\077 (file-modes dir))))
 245       (error "The directory %s is unsafe" dir))))
 246
 247 ;;;###autoload
 248 (defun server-start (&optional leave-dead)
 249   "Allow this Emacs process to be a server for client processes.
 250 This starts a server communications subprocess through which
 251 client \"editors\" can send your editing commands to this Emacs job.
 252 To use the server, set up the program `emacsclient' in the
 253 Emacs distribution as your standard \"editor\".
 254
 255 Prefix arg means just kill any existing server communications subprocess."
 256   (interactive "P")
 257   ;; Make sure there is a safe directory in which to place the socket.
 258   (server-ensure-safe-dir (file-name-directory server-socket-name))
 259   ;; kill it dead!
 260   (if server-process
 261       (condition-case () (delete-process server-process) (error nil)))
 262   ;; Delete the socket files made by previous server invocations.
 263   (condition-case () (delete-file server-socket-name) (error nil))
 264   ;; If this Emacs already had a server, clear out associated status.
 265   (while server-clients
 266     (let ((buffer (nth 1 (car server-clients))))
 267       (server-buffer-done buffer)))
 268   (unless leave-dead
 269     (if server-process
 270         (server-log (message "Restarting server")))
 271     (letf (((default-file-modes) ?\700))
 272       (setq server-process
 273             (make-network-process
 274              :name "server" :family 'local :server t :noquery t
 275              :service server-socket-name
 276              :sentinel 'server-sentinel :filter 'server-process-filter
 277              ;; We must receive file names without being decoded.
 278              ;; Those are decoded by server-process-filter according
 279              ;; to file-name-coding-system.
 280              :coding 'raw-text)))))
 281
 282 ;;;###autoload
 283 (define-minor-mode server-mode
 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
 289   :group 'server
 290   :version "21.4"
 291   ;; Fixme: Should this check for an existing server socket and do
 292   ;; nothing if there is one (for multiple Emacs sessions)?
 293   (server-start (not server-mode)))
 294 \f
 295 (defun server-process-filter (proc string)
 296   "Process a request from the server to edit some files.
 297 PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 298   (server-log string proc)
 299   (let ((prev (process-get proc 'previous-string)))
 300     (when prev
 301       (setq string (concat prev string))
 302       (process-put proc 'previous-string nil)))
 303   ;; If the input is multiple lines,
 304   ;; process each line individually.
 305   (while (string-match "\n" string)
 306     (let ((request (substring string 0 (match-beginning 0)))
 307           (coding-system (and default-enable-multibyte-characters
 308                               (or file-name-coding-system
 309                                   default-file-name-coding-system)))
 310           client nowait eval
 311           (files nil)
 312           (lineno 1)
 313           (columnno 0))
 314       ;; Remove this line from STRING.
 315       (setq string (substring string (match-end 0)))
 316       (setq client (cons proc nil))
 317       (while (string-match "[^ ]* " request)
 318         (let ((arg (substring request (match-beginning 0) (1- (match-end 0)))))
 319           (setq request (substring request (match-end 0)))
 320           (cond
 321            ((equal "-nowait" arg) (setq nowait t))
 322            ((equal "-eval" arg) (setq eval t))
 323            ((and (equal "-display" arg) (string-match "\\([^ ]*\\) " request))
 324             (let ((display (server-unquote-arg (match-string 1 request))))
 325               (setq request (substring request (match-end 0)))
 326               (condition-case err
 327                   (server-select-display display)
 328                 (error (process-send-string proc (nth 1 err))
 329                        (setq request "")))))
 330            ;; Open a new frame at the client.  ARG is the name of the pseudo tty.
 331            ((and (equal "-pty" arg) (string-match "\\([^ ]*\\) \\([^ ]*\\) " request))
 332             (let ((pty (server-unquote-arg (match-string 1 request)))
 333                   (type (server-unquote-arg (match-string 2 request))))
 334               (setq request (substring request (match-end 0)))
 335               (condition-case err
 336                   (let ((frame (make-terminal-frame `((tty . ,pty) (tty-type . ,type)))))
 337                     (setq server-frames (cons (list (car client) frame) server-frames))
 338                     (sit-for 0)
 339                     (process-send-string proc (concat (number-to-string (emacs-pid)) "\n"))
 340                     (select-frame frame))
 341                 (error (process-send-string proc (nth 1 err))
 342                        (setq request "")))))
 343            ;; ARG is a line number option.
 344            ((string-match "\\`\\+[0-9]+\\'" arg)
 345             (setq lineno (string-to-int (substring arg 1))))
 346            ;; ARG is line number:column option.
 347            ((string-match "\\`+\\([0-9]+\\):\\([0-9]+\\)\\'" arg)
 348             (setq lineno (string-to-int (match-string 1 arg))
 349                   columnno (string-to-int (match-string 2 arg))))
 350            (t
 351             ;; Undo the quoting that emacsclient does
 352             ;; for certain special characters.
 353             (setq arg (server-unquote-arg arg))
 354             ;; Now decode the file name if necessary.
 355             (if coding-system
 356                 (setq arg (decode-coding-string arg coding-system)))
 357             (if eval
 358                 (condition-case err
 359                     (let ((v (eval (car (read-from-string arg)))))
 360                       (when v
 361                         (with-temp-buffer
 362                           (let ((standard-output (current-buffer)))
 363                             (pp v)
 364                             (process-send-region proc (point-min) (point-max))))))
 365                   (error (process-send-string proc (concat "*Error* " (error-message-string err)))))
 366
 367               ;; ARG is a file name.
 368               ;; Collapse multiple slashes to single slashes.
 369               (setq arg (command-line-normalize-file-name arg))
 370               (push (list arg lineno columnno) files))
 371             (setq lineno 1)
 372             (setq columnno 0)))))
 373       (when files
 374         (run-hooks 'pre-command-hook)
 375         (server-visit-files files client nowait)
 376         (run-hooks 'post-command-hook))
 377       ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
 378       (if (null (cdr client))
 379           ;; This client is empty; get rid of it immediately.
 380           (progn
 381             (let ((frame (cadr (assq (car client) server-frames))))
 382               ;; Close the client's frame.
 383               (when frame (delete-frame frame)))
 384             (delete-process proc)
 385             (server-log "Close empty client" proc))
 386         ;; We visited some buffer for this client.
 387         (or nowait (push client server-clients))
 388         (unless (or isearch-mode (minibufferp))
 389           (server-switch-buffer (nth 1 client))
 390           (run-hooks 'server-switch-hook)
 391           (unless nowait
 392             (message (substitute-command-keys
 393                       "When done with a buffer, type \\[server-edit]")))))))
 394   ;; Save for later any partial line that remains.
 395   (when (> (length string) 0)
 396     (process-put proc 'previous-string string)))
 397
 398 (defun server-goto-line-column (file-line-col)
 399   (goto-line (nth 1 file-line-col))
 400   (let ((column-number (nth 2 file-line-col)))
 401     (if (> column-number 0)
 402         (move-to-column (1- column-number)))))
 403
 404 (defun server-visit-files (files client &optional nowait)
 405   "Find FILES and return the list CLIENT with the buffers nconc'd.
 406 FILES is an alist whose elements are (FILENAME LINENUMBER COLUMNNUMBER).
 407 NOWAIT non-nil means this client is not waiting for the results,
 408 so don't mark these buffers specially, just visit them normally."
 409   ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries.
 410   (let ((last-nonmenu-event t) client-record)
 411     ;; Restore the current buffer afterward, but not using save-excursion,
 412     ;; because we don't want to save point in this buffer
 413     ;; if it happens to be one of those specified by the server.
 414     (save-current-buffer
 415       (dolist (file files)
 416         ;; If there is an existing buffer modified or the file is
 417         ;; modified, revert it.  If there is an existing buffer with
 418         ;; deleted file, offer to write it.
 419         (let* ((filen (car file))
 420                (obuf (get-file-buffer filen)))
 421           (push filen file-name-history)
 422           (if (and obuf (set-buffer obuf))
 423               (progn
 424                 (cond ((file-exists-p filen)
 425                        (if (not (verify-visited-file-modtime obuf))
 426                            (revert-buffer t nil)))
 427                       (t
 428                        (if (y-or-n-p
 429                             (concat "File no longer exists: "
 430                                     filen
 431                                     ", write buffer to file? "))
 432                            (write-file filen))))
 433                 (setq server-existing-buffer t)
 434                 (server-goto-line-column file))
 435             (set-buffer (find-file-noselect filen))
 436             (server-goto-line-column file)
 437             (run-hooks 'server-visit-hook)))
 438         (unless nowait
 439           ;; When the buffer is killed, inform the clients.
 440           (add-hook 'kill-buffer-hook 'server-kill-buffer nil t)
 441           (push (car client) server-buffer-clients))
 442         (push (current-buffer) client-record)))
 443     (nconc client client-record)))
 444 \f
 445 (defun server-buffer-done (buffer &optional for-killing)
 446   "Mark BUFFER as \"done\" for its client(s).
 447 This buries the buffer, then returns a list of the form (NEXT-BUFFER KILLED).
 448 NEXT-BUFFER is another server buffer, as a suggestion for what to select next,
 449 or nil.  KILLED is t if we killed BUFFER (typically, because it was visiting
 450 a temp file).
 451 FOR-KILLING if non-nil indicates that we are called from `kill-buffer'."
 452   (let ((next-buffer nil)
 453         (killed nil)
 454         (old-clients server-clients))
 455     (while old-clients
 456       (let ((client (car old-clients)))
 457         (or next-buffer
 458             (setq next-buffer (nth 1 (memq buffer client))))
 459         (delq buffer client)
 460         ;; Delete all dead buffers from CLIENT.
 461         (let ((tail client))
 462           (while tail
 463             (and (bufferp (car tail))
 464                  (null (buffer-name (car tail)))
 465                  (delq (car tail) client))
 466             (setq tail (cdr tail))))
 467         ;; If client now has no pending buffers,
 468         ;; tell it that it is done, and forget it entirely.
 469         (unless (cdr client)
 470           (let ((frame (cadr (assq (car client) server-frames))))
 471             ;; Close the client's frame.
 472             (when frame (delete-frame frame)))
 473           (delete-process (car client))
 474           (server-log "Close" (car client))
 475           (setq server-clients (delq client server-clients))))
 476       (setq old-clients (cdr old-clients)))
 477     (if (and (bufferp buffer) (buffer-name buffer))
 478         ;; We may or may not kill this buffer;
 479         ;; if we do, do not call server-buffer-done recursively
 480         ;; from kill-buffer-hook.
 481         (let ((server-kill-buffer-running t))
 482           (with-current-buffer buffer
 483             (setq server-buffer-clients nil)
 484             (run-hooks 'server-done-hook))
 485           ;; Notice whether server-done-hook killed the buffer.
 486           (if (null (buffer-name buffer))
 487               (setq killed t)
 488             ;; Don't bother killing or burying the buffer
 489             ;; when we are called from kill-buffer.
 490             (unless for-killing
 491               (when (and (not killed)
 492                          server-kill-new-buffers
 493                          (with-current-buffer buffer
 494                            (not server-existing-buffer)))
 495                 (setq killed t)
 496                 (bury-buffer buffer)
 497                 (kill-buffer buffer))
 498               (unless killed
 499                 (if (server-temp-file-p buffer)
 500                     (progn
 501                       (kill-buffer buffer)
 502                       (setq killed t))
 503                   (bury-buffer buffer)))))))
 504     (list next-buffer killed)))
 505
 506 (defun server-temp-file-p (&optional buffer)
 507   "Return non-nil if BUFFER contains a file considered temporary.
 508 These are files whose names suggest they are repeatedly
 509 reused to pass information to another program.
 510
 511 The variable `server-temp-file-regexp' controls which filenames
 512 are considered temporary."
 513   (and (buffer-file-name buffer)
 514        (string-match server-temp-file-regexp (buffer-file-name buffer))))
 515
 516 (defun server-done ()
 517   "Offer to save current buffer, mark it as \"done\" for clients.
 518 This kills or buries the buffer, then returns a list
 519 of the form (NEXT-BUFFER KILLED).  NEXT-BUFFER is another server buffer,
 520 as a suggestion for what to select next, or nil.
 521 KILLED is t if we killed BUFFER, which happens if it was created
 522 specifically for the clients and did not exist before their request for it."
 523   (when server-buffer-clients
 524     (if (server-temp-file-p)
 525         ;; For a temp file, save, and do make a non-numeric backup
 526         ;; (unless make-backup-files is nil).
 527         (let ((version-control nil)
 528               (buffer-backed-up nil))
 529           (save-buffer))
 530       (if (and (buffer-modified-p)
 531                buffer-file-name
 532                (y-or-n-p (concat "Save file " buffer-file-name "? ")))
 533           (save-buffer)))
 534     (server-buffer-done (current-buffer))))
 535
 536 ;; Ask before killing a server buffer.
 537 ;; It was suggested to release its client instead,
 538 ;; but I think that is dangerous--the client would proceed
 539 ;; using whatever is on disk in that file. -- rms.
 540 (defun server-kill-buffer-query-function ()
 541   (or (not server-buffer-clients)
 542       (yes-or-no-p (format "Buffer `%s' still has clients; kill it? "
 543                            (buffer-name (current-buffer))))))
 544
 545 (add-hook 'kill-buffer-query-functions
 546           'server-kill-buffer-query-function)
 547
 548 (defun server-kill-emacs-query-function ()
 549   (let (live-client
 550         (tail server-clients))
 551     ;; See if any clients have any buffers that are still alive.
 552     (while tail
 553       (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail)))))
 554           (setq live-client t))
 555       (setq tail (cdr tail)))
 556     (or (not live-client)
 557         (yes-or-no-p "Server buffers still have clients; exit anyway? "))))
 558
 559 (add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
 560
 561 (defvar server-kill-buffer-running nil
 562   "Non-nil while `server-kill-buffer' or `server-buffer-done' is running.")
 563
 564 (defun server-kill-buffer ()
 565   ;; Prevent infinite recursion if user has made server-done-hook
 566   ;; call kill-buffer.
 567   (or server-kill-buffer-running
 568       (and server-buffer-clients
 569            (let ((server-kill-buffer-running t))
 570              (when server-process
 571                (server-buffer-done (current-buffer) t))))))
 572 \f
 573 (defun server-edit (&optional arg)
 574   "Switch to next server editing buffer; say \"Done\" for current buffer.
 575 If a server buffer is current, it is marked \"done\" and optionally saved.
 576 The buffer is also killed if it did not exist before the clients asked for it.
 577 When all of a client's buffers are marked as \"done\", the client is notified.
 578
 579 Temporary files such as MH <draft> files are always saved and backed up,
 580 no questions asked.  (The variable `make-backup-files', if nil, still
 581 inhibits a backup; you can set it locally in a particular buffer to
 582 prevent a backup for it.)  The variable `server-temp-file-regexp' controls
 583 which filenames are considered temporary.
 584
 585 If invoked with a prefix argument, or if there is no server process running,
 586 starts server process and that is all.  Invoked by \\[server-edit]."
 587   (interactive "P")
 588   (if (or arg
 589           (not server-process)
 590           (memq (process-status server-process) '(signal exit)))
 591       (server-start nil)
 592     (apply 'server-switch-buffer (server-done))))
 593
 594 (defun server-switch-buffer (&optional next-buffer killed-one)
 595   "Switch to another buffer, preferably one that has a client.
 596 Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
 597   ;; KILLED-ONE is t in a recursive call
 598   ;; if we have already killed one temp-file server buffer.
 599   ;; This means we should avoid the final "switch to some other buffer"
 600   ;; since we've already effectively done that.
 601   (if (null next-buffer)
 602       (if server-clients
 603           (server-switch-buffer (nth 1 (car server-clients)) killed-one)
 604         (unless (or killed-one (window-dedicated-p (selected-window)))
 605           (switch-to-buffer (other-buffer))
 606           (message "No server buffers remain to edit")))
 607     (if (not (buffer-name next-buffer))
 608         ;; If NEXT-BUFFER is a dead buffer, remove the server records for it
 609         ;; and try the next surviving server buffer.
 610         (apply 'server-switch-buffer (server-buffer-done next-buffer))
 611       ;; OK, we know next-buffer is live, let's display and select it.
 612       (if (functionp server-window)
 613           (funcall server-window next-buffer)
 614         (let ((win (get-buffer-window next-buffer 0)))
 615           (if (and win (not server-window))
 616               ;; The buffer is already displayed: just reuse the window.
 617               (let ((frame (window-frame win)))
 618                 (if (eq (frame-visible-p frame) 'icon)
 619                     (raise-frame frame))
 620                 (select-window win)
 621                 (set-buffer next-buffer))
 622             ;; Otherwise, let's find an appropriate window.
 623             (cond ((and (windowp server-window)
 624                         (window-live-p server-window))
 625                    (select-window server-window))
 626                   ((framep server-window)
 627                    (if (not (frame-live-p server-window))
 628                        (setq server-window (make-frame)))
 629                    (select-window (frame-selected-window server-window))))
 630             (if (window-minibuffer-p (selected-window))
 631                 (select-window (next-window nil 'nomini 0)))
 632             ;; Move to a non-dedicated window, if we have one.
 633             (when (window-dedicated-p (selected-window))
 634               (select-window
 635                (get-window-with-predicate
 636                 (lambda (w)
 637                   (and (not (window-dedicated-p w))
 638                        (equal (frame-parameter (window-frame w) 'display)
 639                               (frame-parameter (selected-frame) 'display))))
 640                 'nomini 'visible (selected-window))))
 641             (condition-case nil
 642                 (switch-to-buffer next-buffer)
 643               ;; After all the above, we might still have ended up with
 644               ;; a minibuffer/dedicated-window (if there's no other).
 645               (error (pop-to-buffer next-buffer)))))))))
 646
 647 (global-set-key "\C-x#" 'server-edit)
 648
 649 (defun server-unload-hook ()
 650   (server-start t)
 651   (remove-hook 'kill-buffer-query-functions 'server-kill-buffer-query-function)
 652   (remove-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function)
 653   (remove-hook 'kill-buffer-hook 'server-kill-buffer))
 654 \f
 655 (provide 'server)
 656
 657 ;;; arch-tag: 1f7ecb42-f00a-49f8-906d-61995d84c8d6
 658 ;;; server.el ends here