server.el 11.6 KB
Newer Older
root's avatar
root committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
;; Lisp code for GNU Emacs running as server process.
;; Copyright (C) 1986, 1987 Free Software Foundation, Inc.
;; Author William Sommerfeld, wesommer@athena.mit.edu.
;; Changes by peck@sun.com and by rms.

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 1, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.


;;; This Lisp code is run in Emacs when it is to operate as
;;; a server for other processes.

;;; Load this library and do M-x server-edit to enable Emacs as a server.
Jim Blandy's avatar
Jim Blandy committed
27
;;; Emacs runs the program ../arch-lib/emacsserver as a subprocess
root's avatar
root committed
28 29 30 31
;;; for communication with clients.  If there are no client buffers to edit, 
;;; server-edit acts like (switch-to-buffer (other-buffer))

;;; When some other program runs "the editor" to edit a file,
Jim Blandy's avatar
Jim Blandy committed
32
;;; "the editor" can be the Emacs client program ../lib-src/emacsclient.
root's avatar
root committed
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
;;; This program transmits the file names to Emacs through
;;; the server subprocess, and Emacs visits them and lets you edit them.

;;; Note that any number of clients may dispatch files to emacs to be edited.

;;; When you finish editing a Server buffer, again call server-edit
;;; to mark that buffer as done for the client and switch to the next 
;;; Server buffer.  When all the buffers for a client have been edited 
;;; and exited with server-edit, the client "editor" will return
;;; to the program that invoked it.  

;;; Your editing commands and Emacs's display output go to and from
;;; the terminal in the usual way.  Thus, server operation is possible
;;; only when Emacs can talk to the terminal at the time you invoke
;;; the client.  This is possible in four cases:

;;; 1. On a window system, where Emacs runs in one window and the
;;; program that wants to use "the editor" runs in another.

;;; 2. On a multi-terminal system, where Emacs runs on one terminal and the
;;; program that wants to use "the editor" runs on another.

;;; 3. When the program that wants to use "the editor" is running
;;; as a subprocess of Emacs.

;;; 4. On a system with job control, when Emacs is suspended, the program
;;; that wants to use "the editor" will stop and display
;;; "Waiting for Emacs...".  It can then be suspended, and Emacs can be
;;; brought into the foreground for editing.  When done editing, Emacs is
;;; suspended again, and the client program is brought into the foreground.

;;; The buffer local variable "server-buffer-clients" lists 
;;; the clients who are waiting for this buffer to be edited.  
;;; The global variable "server-clients" lists all the waiting clients,
;;; and which files are yet to be edited for each.

(defvar server-program "emacsserver"
  "*The program to use as the edit server")

(defvar server-visit-hook nil
  "*List of hooks to call when switching to a buffer for the Emacs server.")

(defvar server-process nil 
  "the current server process")

78 79
(defvar server-previous-string "")

root's avatar
root committed
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116
(defvar server-clients nil
  "List of current server clients.
Each element is (CLIENTID FILES...) where CLIENTID is a string
that can be given to the server process to identify a client.
When a buffer is marked as \"done\", it is removed from this list.")

(defvar server-buffer-clients nil
  "List of clientids for clients requesting editing of current buffer.")
;; Changing major modes should not erase this local.
(put 'server-buffer-clients 'permanent-local t)

(defvar server-temp-file-regexp "^/tmp/Re\\|/draft$"
  "*Regexp which should match filenames of temporary files
which are deleted and reused after each edit
by the programs that invoke the emacs server.")

(make-variable-buffer-local 'server-buffer-clients)
(setq-default server-buffer-clients nil)
(or (assq 'server-buffer-clients minor-mode-alist)
    (setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))

;; If a *server* buffer exists,
;; write STRING to it for logging purposes.
(defun server-log (string)
  (if (get-buffer "*server*")
      (save-excursion
	(set-buffer "*server*")
	(goto-char (point-max))
	(insert string)
	(or (bobp) (newline)))))

(defun server-sentinel (proc msg)
  (cond ((eq (process-status proc) 'exit)
	 (server-log (message "Server subprocess exited")))
	((eq (process-status proc) 'signal)
	 (server-log (message "Server subprocess killed")))))

Roland McGrath's avatar
Roland McGrath committed
117
;;;###autoload
root's avatar
root committed
118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149
(defun server-start (&optional leave-dead)
  "Allow this Emacs process to be a server for client processes.
This starts a server communications subprocess through which
client \"editors\" can send your editing commands to this Emacs job.
To use the server, set up the program `etc/emacsclient' in the
Emacs distribution as your standard \"editor\".

Prefix arg means just kill any existing server communications subprocess."
  (interactive "P")
  ;; kill it dead!
  (if server-process
      (progn
	(set-process-sentinel server-process nil)
	(condition-case () (delete-process server-process) (error nil))))
  (condition-case () (delete-file "~/.emacs_server") (error nil))
  ;; If we already had a server, clear out associated status.
  (while server-clients
    (let ((buffer (nth 1 (car server-clients))))
      (server-buffer-done buffer)))
  (if leave-dead
      nil
    (if server-process
	(server-log (message "Restarting server")))
    (setq server-process (start-process "server" nil server-program))
    (set-process-sentinel server-process 'server-sentinel)
    (set-process-filter server-process 'server-process-filter)
    (process-kill-without-query server-process)))

;Process a request from the server to edit some files.
;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
(defun server-process-filter (proc string)
  (server-log string)
150 151 152 153 154 155
  (setq string (concat server-previous-string string))
  (if (not (and (eq ?\n (aref string (1- (length string))))
		(eq 0 (string-match "Client: " string))))
      ;; If input is not complete, save it for later.
      (setq server-previous-string string)
    ;; If it is complete, process it now, and discard what was saved.
root's avatar
root committed
156
    (setq string (substring string (match-end 0)))
157
    (setq server-previous-string "")
root's avatar
root committed
158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298
    (let ((client (list (substring string 0 (string-match " " string))))
	  (files nil)
	  (lineno 1))
      (setq string (substring string (match-end 0)))
      (while (string-match "[^ ]+ " string)
	(let ((arg
	       (substring string (match-beginning 0) (1- (match-end 0)))))
	  (setq string (substring string (match-end 0)))
	  (if (string-match "\\`\\+[0-9]+\\'" arg)
	      (setq lineno (read (substring arg 1)))
	    (setq files
		  (cons (list arg lineno)
			files))
	    (setq lineno 1))))
      (server-visit-files files client)
      ;; CLIENT is now a list (CLIENTNUM BUFFERS...)
      (setq server-clients (cons client server-clients))
      (switch-to-buffer (nth 1 client))
      (message (substitute-command-keys
		"When done with a buffer, type \\[server-edit].")))))

(defun server-visit-files (files client)
  "Finds FILES and returns the list CLIENT with the buffers nconc'd.
FILES is an alist whose elements are (FILENAME LINENUMBER)."
  (let (client-record)
    (while files
      (save-excursion
	;; If there is an existing buffer modified or the file is modified,
	;; revert it.
	;; If there is an existing buffer with deleted file, offer to write it.
 	(let* ((filen (car (car files)))
	       (obuf (get-file-buffer filen)))
 	  (if (and obuf (set-buffer obuf))
 	      (if (file-exists-p filen)
 		  (if (or (not (verify-visited-file-modtime obuf))
			  (buffer-modified-p obuf))
		      (revert-buffer t nil))
 		(if (y-or-n-p
 		     (concat "File no longer exists: "
 			     filen
 			     ", write buffer to file? "))
 		    (write-file filen)))
 	    (set-buffer (find-file-noselect filen))
	    (run-hooks 'server-visit-hook)))
	(goto-line (nth 1 (car files)))
  	(setq server-buffer-clients (cons (car client) server-buffer-clients))
  	(setq client-record (cons (current-buffer) client-record)))
        (setq files (cdr files)))
    (nconc client client-record)))

(defun server-buffer-done (buffer)
  "Mark BUFFER as \"done\" for its client(s).
Buries the buffer, and returns another server buffer
as a suggestion for what to select next."
  (let ((running (eq (process-status server-process) 'run))
	(next-buffer nil)
	(old-clients server-clients))
    (while old-clients
      (let ((client (car old-clients)))
	(or next-buffer 
	    (setq next-buffer (nth 1 (memq buffer client))))
	(delq buffer client)
	;; If client now has no pending buffers,
	;; tell it that it is done, and forget it entirely.
	(if (cdr client) nil
	  (if running
	      (progn
		(send-string server-process 
			     (format "Close: %s Done\n" (car client)))
		(server-log (format "Close: %s Done\n" (car client)))))
	  (setq server-clients (delq client server-clients))))
      (setq old-clients (cdr old-clients)))
    (if (buffer-name buffer)
	(save-excursion
	  (set-buffer buffer)
	  (setq server-buffer-clients nil)))
    (bury-buffer buffer)
    next-buffer))

(defun server-temp-file-p (buffer)
  "Return non-nil if BUFFER contains a file considered temporary.
These are files whose names suggest they are repeatedly
reused to pass information to another program.

The variable `server-temp-file-regexp' controls which filenames
are considered temporary."
  (and (buffer-file-name buffer)
       (string-match server-temp-file-regexp (buffer-file-name buffer))))

(defun server-done ()
  "Offer to save current buffer, mark it as \"done\" for clients,
bury it, and return a suggested buffer to select next."
  (let ((buffer (current-buffer)))
    (if server-buffer-clients
	(progn
 	  (if (server-temp-file-p buffer)
 	      (progn (save-buffer)
		     (write-region (point-min) (point-max)
				   (concat buffer-file-name "~"))
		     (kill-buffer buffer))
	    (if (and (buffer-modified-p)
		     (y-or-n-p (concat "Save file " buffer-file-name "? ")))
		(save-buffer buffer)))
	  (server-buffer-done buffer)))))

(defun server-edit (&optional arg)
  "Switch to next server editing buffer; say \"Done\" for current buffer.
If a server buffer is current, it is marked \"done\" and optionally saved.
When all of a client's buffers are marked as \"done\", the client is notified.

Temporary files such as MH <draft> files are always saved and backed up,
no questions asked.  The variable `server-temp-file-regexp' controls
which filenames are considered temporary.

If invoked with a prefix argument, or if there is no server process running, 
starts server process and that is all.  Invoked by \\[server-edit]."

  (interactive "P")
  (if (or arg
	  (not server-process)
	  (memq (process-status server-process) '(signal exit)))
      (server-start nil)
    (server-switch-buffer (server-done))))

(defun server-switch-buffer (next-buffer)
  "Switch to another buffer, preferably one that has a client.
Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
  (if next-buffer
      (if (and (bufferp next-buffer)
	       (buffer-name next-buffer))
	  (switch-to-buffer next-buffer)
	;; If NEXT-BUFFER is a dead buffer,
	;; remove the server records for it
	;; and try the next surviving server buffer.
	(server-switch-buffer
	 (server-buffer-done next-buffer)))
    (if server-clients
	(server-switch-buffer (nth 1 (car server-clients)))
      (switch-to-buffer (other-buffer)))))

(global-set-key "\C-x#" 'server-edit)