1;;; server.el --- Lisp code for GNU Emacs running as server process. 2 3;; Copyright (C) 1986, 1987, 1992, 1994 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 GNU Emacs. 11 12;; GNU Emacs is free software; you can redistribute it and/or modify 13;; it 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;; GNU Emacs is distributed in the hope that it will be useful, 18;; but WITHOUT ANY WARRANTY; without even the implied warranty of 19;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20;; GNU General Public License for more details. 21 22;; You should have received a copy of the GNU General Public License 23;; along with GNU Emacs; see the file COPYING. If not, write to 24;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 25 26;;; Commentary: 27 28;;; This Lisp code is run in Emacs when it is to operate as 29;;; a server for other processes. 30 31;;; Load this library and do M-x server-edit to enable Emacs as a server. 32;;; Emacs runs the program ../arch-lib/emacsserver as a subprocess 33;;; for communication with clients. If there are no client buffers to edit, 34;;; server-edit acts like (switch-to-buffer (other-buffer)) 35 36;;; When some other program runs "the editor" to edit a file, 37;;; "the editor" can be the Emacs client program ../lib-src/emacsclient. 38;;; This program transmits the file names to Emacs through 39;;; the server subprocess, and Emacs visits them and lets you edit them. 40 41;;; Note that any number of clients may dispatch files to emacs to be edited. 42 43;;; When you finish editing a Server buffer, again call server-edit 44;;; to mark that buffer as done for the client and switch to the next 45;;; Server buffer. When all the buffers for a client have been edited 46;;; and exited with server-edit, the client "editor" will return 47;;; to the program that invoked it. 48 49;;; Your editing commands and Emacs's display output go to and from 50;;; the terminal in the usual way. Thus, server operation is possible 51;;; only when Emacs can talk to the terminal at the time you invoke 52;;; the client. This is possible in four cases: 53 54;;; 1. On a window system, where Emacs runs in one window and the 55;;; program that wants to use "the editor" runs in another. 56 57;;; 2. On a multi-terminal system, where Emacs runs on one terminal and the 58;;; program that wants to use "the editor" runs on another. 59 60;;; 3. When the program that wants to use "the editor" is running 61;;; as a subprocess of Emacs. 62 63;;; 4. On a system with job control, when Emacs is suspended, the program 64;;; that wants to use "the editor" will stop and display 65;;; "Waiting for Emacs...". It can then be suspended, and Emacs can be 66;;; brought into the foreground for editing. When done editing, Emacs is 67;;; suspended again, and the client program is brought into the foreground. 68 69;;; The buffer local variable "server-buffer-clients" lists 70;;; the clients who are waiting for this buffer to be edited. 71;;; The global variable "server-clients" lists all the waiting clients, 72;;; and which files are yet to be edited for each. 73 74;;; Code: 75 76(defvar server-program (expand-file-name "emacsserver" exec-directory) 77 "*The program to use as the edit server.") 78 79(defvar server-visit-hook nil 80 "*List of hooks to call when visiting a file for the Emacs server.") 81 82(defvar server-switch-hook nil 83 "*List of hooks to call when switching to a buffer for the Emacs server.") 84 85(defvar server-done-hook nil 86 "*List of hooks to call when done editing a buffer for the Emacs server.") 87 88(defvar server-process nil 89 "the current server process") 90 91(defvar server-previous-string "") 92 93(defvar server-clients nil 94 "List of current server clients. 95Each element is (CLIENTID BUFFERS...) where CLIENTID is a string 96that can be given to the server process to identify a client. 97When a buffer is marked as \"done\", it is removed from this list.") 98 99(defvar server-buffer-clients nil 100 "List of clientids for clients requesting editing of current buffer.") 101(make-variable-buffer-local 'server-buffer-clients) 102;; Changing major modes should not erase this local. 103(put 'server-buffer-clients 'permanent-local t) 104 105(defvar server-window nil 106 "*The window to use for selecting Emacs server buffers. 107If nil, use the selected window. 108If it is a frame, use the frame's selected window.") 109 110(defvar server-temp-file-regexp "^/tmp/Re\\|/draft$" 111 "*Regexp which should match filenames of temporary files 112which are deleted and reused after each edit 113by the programs that invoke the emacs server.") 114 115(or (assq 'server-buffer-clients minor-mode-alist) 116 (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist))) 117 118;; If a *server* buffer exists, 119;; write STRING to it for logging purposes. 120(defun server-log (string) 121 (if (get-buffer "*server*") 122 (save-excursion 123 (set-buffer "*server*") 124 (goto-char (point-max)) 125 (insert string) 126 (or (bobp) (newline))))) 127 128(defun server-sentinel (proc msg) 129 (cond ((eq (process-status proc) 'exit) 130 (server-log (message "Server subprocess exited"))) 131 ((eq (process-status proc) 'signal) 132 (server-log (message "Server subprocess killed"))))) 133 134;;;###autoload 135(defun server-start (&optional leave-dead) 136 "Allow this Emacs process to be a server for client processes. 137This starts a server communications subprocess through which 138client \"editors\" can send your editing commands to this Emacs job. 139To use the server, set up the program `etc/emacsclient' in the 140Emacs distribution as your standard \"editor\". 141 142Prefix arg means just kill any existing server communications subprocess." 143 (interactive "P") 144 ;; kill it dead! 145 (if server-process 146 (progn 147 (set-process-sentinel server-process nil) 148 (condition-case () (delete-process server-process) (error nil)))) 149 (condition-case () (delete-file "~/.emacs_server") (error nil)) 150 ;; If we already had a server, clear out associated status. 151 (while server-clients 152 (let ((buffer (nth 1 (car server-clients)))) 153 (server-buffer-done buffer))) 154 (if leave-dead 155 nil 156 (if server-process 157 (server-log (message "Restarting server"))) 158 (setq server-process (start-process "server" nil server-program)) 159 (set-process-sentinel server-process 'server-sentinel) 160 (set-process-filter server-process 'server-process-filter) 161 (process-kill-without-query server-process))) 162 163;Process a request from the server to edit some files. 164;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n" 165(defun server-process-filter (proc string) 166 (server-log string) 167 (setq string (concat server-previous-string string)) 168 (if (not (and (eq ?\n (aref string (1- (length string)))) 169 (eq 0 (string-match "Client: " string)))) 170 ;; If input is not complete, save it for later. 171 (setq server-previous-string string) 172 ;; If it is complete, process it now, and discard what was saved. 173 (setq string (substring string (match-end 0))) 174 (setq server-previous-string "") 175 (let ((client (list (substring string 0 (string-match " " string)))) 176 (files nil) 177 (lineno 1)) 178 (setq string (substring string (match-end 0))) 179 (while (string-match "[^ ]+ " string) 180 (let ((arg 181 (substring string (match-beginning 0) (1- (match-end 0))))) 182 (setq string (substring string (match-end 0))) 183 (if (string-match "\\`\\+[0-9]+\\'" arg) 184 (setq lineno (read (substring arg 1))) 185 (setq files 186 (cons (list arg lineno) 187 files)) 188 (setq lineno 1)))) 189 (server-visit-files files client) 190 ;; CLIENT is now a list (CLIENTNUM BUFFERS...) 191 (setq server-clients (cons client server-clients)) 192 (server-switch-buffer (nth 1 client)) 193 (run-hooks 'server-switch-hook) 194 (message (substitute-command-keys 195 "When done with a buffer, type \\[server-edit]."))))) 196 197(defun server-visit-files (files client) 198 "Finds FILES and returns the list CLIENT with the buffers nconc'd. 199FILES is an alist whose elements are (FILENAME LINENUMBER)." 200 ;; Bind last-nonmenu-event to force use of keyboard, not mouse, for queries. 201 (let (client-record (last-nonmenu-event t) (obuf (current-buffer))) 202 ;; Restore the current buffer afterward, but not using save-excursion, 203 ;; because we don't want to save point in this buffer 204 ;; if it happens to be one of those specified by the server. 205 (unwind-protect 206 (while files 207 ;; If there is an existing buffer modified or the file is modified, 208 ;; revert it. 209 ;; If there is an existing buffer with deleted file, offer to write it. 210 (let* ((filen (car (car files))) 211 (obuf (get-file-buffer filen))) 212 (if (and obuf (set-buffer obuf)) 213 (if (file-exists-p filen) 214 (if (or (not (verify-visited-file-modtime obuf)) 215 (buffer-modified-p obuf)) 216 (revert-buffer t nil)) 217 (if (y-or-n-p 218 (concat "File no longer exists: " 219 filen 220 ", write buffer to file? ")) 221 (write-file filen))) 222 (set-buffer (find-file-noselect filen)) 223 (run-hooks 'server-visit-hook))) 224 (goto-line (nth 1 (car files))) 225 (setq server-buffer-clients (cons (car client) server-buffer-clients)) 226 (setq client-record (cons (current-buffer) client-record)) 227 (setq files (cdr files))) 228 (set-buffer obuf)) 229 (nconc client client-record))) 230 231(defun server-buffer-done (buffer) 232 "Mark BUFFER as \"done\" for its client(s). 233Buries the buffer, and returns another server buffer 234as a suggestion for what to select next." 235 (let ((running (eq (process-status server-process) 'run)) 236 (next-buffer nil) 237 (old-clients server-clients)) 238 (while old-clients 239 (let ((client (car old-clients))) 240 (or next-buffer 241 (setq next-buffer (nth 1 (memq buffer client)))) 242 (delq buffer client) 243 ;; If client now has no pending buffers, 244 ;; tell it that it is done, and forget it entirely. 245 (if (cdr client) nil 246 (if running 247 (progn 248 (send-string server-process 249 (format "Close: %s Done\n" (car client))) 250 (server-log (format "Close: %s Done\n" (car client))))) 251 (setq server-clients (delq client server-clients)))) 252 (setq old-clients (cdr old-clients))) 253 (if (buffer-name buffer) 254 (progn 255 (save-excursion 256 (set-buffer buffer) 257 (setq server-buffer-clients nil) 258 (run-hooks 'server-done-hook)) 259 (if (server-temp-file-p buffer) 260 (kill-buffer buffer) 261 (bury-buffer buffer)))) 262 next-buffer)) 263 264(defun server-temp-file-p (buffer) 265 "Return non-nil if BUFFER contains a file considered temporary. 266These are files whose names suggest they are repeatedly 267reused to pass information to another program. 268 269The variable `server-temp-file-regexp' controls which filenames 270are considered temporary." 271 (and (buffer-file-name buffer) 272 (string-match server-temp-file-regexp (buffer-file-name buffer)))) 273 274(defun server-done () 275 "Offer to save current buffer, mark it as \"done\" for clients. 276Then bury it, and return a suggested buffer to select next." 277 (let ((buffer (current-buffer))) 278 (if server-buffer-clients 279 (progn 280 (if (server-temp-file-p buffer) 281 ;; For a temp file, save, and do make a non-numeric backup 282 ;; (unless make-backup-files is nil). 283 (let ((version-control nil) 284 (buffer-backed-up nil)) 285 (save-buffer)) 286 (if (and (buffer-modified-p) 287 (y-or-n-p (concat "Save file " buffer-file-name "? "))) 288 (save-buffer buffer))) 289 (server-buffer-done buffer))))) 290 291;; If a server buffer is killed, release its client. 292;; I'm not sure this is really a good idea--do you want the client 293;; to proceed using whatever is on disk in that file? 294(defun server-kill-buffer-query-function () 295 (or (not server-buffer-clients) 296 (yes-or-no-p (format "Buffer `%s' still has clients; kill it? " 297 (buffer-name (current-buffer)))))) 298 299(add-hook 'kill-buffer-query-functions 300 'server-kill-buffer-query-function) 301 302(defun server-kill-emacs-query-function () 303 (let (live-client 304 (tail server-clients)) 305 ;; See if any clients have any buffers that are still alive. 306 (while tail 307 (if (memq t (mapcar 'stringp (mapcar 'buffer-name (cdr (car tail))))) 308 (setq live-client t)) 309 (setq tail (cdr tail))) 310 (or (not live-client) 311 (yes-or-no-p "Server buffers still have clients; exit anyway? ")))) 312 313(add-hook 'kill-emacs-query-functions 'server-kill-emacs-query-function) 314 315(defun server-edit (&optional arg) 316 "Switch to next server editing buffer; say \"Done\" for current buffer. 317If a server buffer is current, it is marked \"done\" and optionally saved. 318When all of a client's buffers are marked as \"done\", the client is notified. 319 320Temporary files such as MH <draft> files are always saved and backed up, 321no questions asked. (The variable `make-backup-files', if nil, still 322inhibits a backup; you can set it locally in a particular buffer to 323prevent a backup for it.) The variable `server-temp-file-regexp' controls 324which filenames are considered temporary. 325 326If invoked with a prefix argument, or if there is no server process running, 327starts server process and that is all. Invoked by \\[server-edit]." 328 329 (interactive "P") 330 (if (or arg 331 (not server-process) 332 (memq (process-status server-process) '(signal exit))) 333 (server-start nil) 334 (server-switch-buffer (server-done)))) 335 336(defun server-switch-buffer (next-buffer) 337 "Switch to another buffer, preferably one that has a client. 338Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it." 339 (cond ((windowp server-window) 340 (select-window server-window)) 341 ((framep server-window) 342 (select-window (frame-selected-window server-window)))) 343 (if (window-minibuffer-p (selected-window)) 344 (select-window (next-window nil 'nomini t))) 345 (if next-buffer 346 (if (and (bufferp next-buffer) 347 (buffer-name next-buffer)) 348 (switch-to-buffer next-buffer) 349 ;; If NEXT-BUFFER is a dead buffer, 350 ;; remove the server records for it 351 ;; and try the next surviving server buffer. 352 (server-switch-buffer 353 (server-buffer-done next-buffer))) 354 (if server-clients 355 (server-switch-buffer (nth 1 (car server-clients))) 356 (switch-to-buffer (other-buffer))))) 357 358(global-set-key "\C-x#" 'server-edit) 359 360(provide 'server) 361 362;;; server.el ends here 363