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311 lines
12 KiB
EmacsLisp
311 lines
12 KiB
EmacsLisp
;;; server.el --- Lisp code for GNU Emacs running as server process.
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;; Copyright (C) 1986, 1987, 1992 Free Software Foundation, Inc.
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;; Author: William Sommerfeld <wesommer@athena.mit.edu>
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;; Keywords: processes
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;; Changes by peck@sun.com and by rms.
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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;;; Commentary:
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;;; This Lisp code is run in Emacs when it is to operate as
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;;; a server for other processes.
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;;; Load this library and do M-x server-edit to enable Emacs as a server.
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;;; Emacs runs the program ../arch-lib/emacsserver as a subprocess
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;;; for communication with clients. If there are no client buffers to edit,
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;;; server-edit acts like (switch-to-buffer (other-buffer))
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;;; When some other program runs "the editor" to edit a file,
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;;; "the editor" can be the Emacs client program ../lib-src/emacsclient.
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;;; This program transmits the file names to Emacs through
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;;; the server subprocess, and Emacs visits them and lets you edit them.
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;;; Note that any number of clients may dispatch files to emacs to be edited.
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;;; When you finish editing a Server buffer, again call server-edit
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;;; to mark that buffer as done for the client and switch to the next
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;;; Server buffer. When all the buffers for a client have been edited
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;;; and exited with server-edit, the client "editor" will return
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;;; to the program that invoked it.
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;;; Your editing commands and Emacs's display output go to and from
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;;; the terminal in the usual way. Thus, server operation is possible
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;;; only when Emacs can talk to the terminal at the time you invoke
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;;; the client. This is possible in four cases:
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;;; 1. On a window system, where Emacs runs in one window and the
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;;; program that wants to use "the editor" runs in another.
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;;; 2. On a multi-terminal system, where Emacs runs on one terminal and the
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;;; program that wants to use "the editor" runs on another.
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;;; 3. When the program that wants to use "the editor" is running
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;;; as a subprocess of Emacs.
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;;; 4. On a system with job control, when Emacs is suspended, the program
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;;; that wants to use "the editor" will stop and display
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;;; "Waiting for Emacs...". It can then be suspended, and Emacs can be
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;;; brought into the foreground for editing. When done editing, Emacs is
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;;; suspended again, and the client program is brought into the foreground.
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;;; The buffer local variable "server-buffer-clients" lists
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;;; the clients who are waiting for this buffer to be edited.
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;;; The global variable "server-clients" lists all the waiting clients,
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;;; and which files are yet to be edited for each.
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;;; Code:
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(defvar server-program "emacsserver"
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"*The program to use as the edit server")
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(defvar server-visit-hook nil
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"*List of hooks to call when switching to a buffer for the Emacs server.")
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(defvar server-process nil
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"the current server process")
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(defvar server-previous-string "")
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(defvar server-clients nil
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"List of current server clients.
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Each element is (CLIENTID FILES...) where CLIENTID is a string
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that can be given to the server process to identify a client.
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When a buffer is marked as \"done\", it is removed from this list.")
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(defvar server-buffer-clients nil
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"List of clientids for clients requesting editing of current buffer.")
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;; Changing major modes should not erase this local.
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(put 'server-buffer-clients 'permanent-local t)
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(defvar server-temp-file-regexp "^/tmp/Re\\|/draft$"
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"*Regexp which should match filenames of temporary files
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which are deleted and reused after each edit
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by the programs that invoke the emacs server.")
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(make-variable-buffer-local 'server-buffer-clients)
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(put 'server-buffer-clients 'permanent-local t)
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(setq-default server-buffer-clients nil)
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(or (assq 'server-buffer-clients minor-mode-alist)
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(setq minor-mode-alist (cons '(server-buffer-clients " Server") minor-mode-alist)))
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;; If a *server* buffer exists,
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;; write STRING to it for logging purposes.
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(defun server-log (string)
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(if (get-buffer "*server*")
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(save-excursion
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(set-buffer "*server*")
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(goto-char (point-max))
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(insert string)
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(or (bobp) (newline)))))
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(defun server-sentinel (proc msg)
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(cond ((eq (process-status proc) 'exit)
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(server-log (message "Server subprocess exited")))
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((eq (process-status proc) 'signal)
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(server-log (message "Server subprocess killed")))))
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;;;###autoload
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(defun server-start (&optional leave-dead)
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"Allow this Emacs process to be a server for client processes.
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This starts a server communications subprocess through which
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client \"editors\" can send your editing commands to this Emacs job.
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To use the server, set up the program `etc/emacsclient' in the
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Emacs distribution as your standard \"editor\".
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Prefix arg means just kill any existing server communications subprocess."
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(interactive "P")
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;; kill it dead!
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(if server-process
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(progn
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(set-process-sentinel server-process nil)
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(condition-case () (delete-process server-process) (error nil))))
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(condition-case () (delete-file "~/.emacs_server") (error nil))
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;; If we already had a server, clear out associated status.
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(while server-clients
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(let ((buffer (nth 1 (car server-clients))))
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(server-buffer-done buffer)))
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(if leave-dead
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nil
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(if server-process
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(server-log (message "Restarting server")))
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(setq server-process (start-process "server" nil server-program))
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(set-process-sentinel server-process 'server-sentinel)
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(set-process-filter server-process 'server-process-filter)
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(process-kill-without-query server-process)))
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;Process a request from the server to edit some files.
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;Format of STRING is "Client: CLIENTID PATH PATH PATH... \n"
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(defun server-process-filter (proc string)
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(server-log string)
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(setq string (concat server-previous-string string))
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(if (not (and (eq ?\n (aref string (1- (length string))))
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(eq 0 (string-match "Client: " string))))
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;; If input is not complete, save it for later.
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(setq server-previous-string string)
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;; If it is complete, process it now, and discard what was saved.
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(setq string (substring string (match-end 0)))
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(setq server-previous-string "")
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(let ((client (list (substring string 0 (string-match " " string))))
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(files nil)
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(lineno 1))
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(setq string (substring string (match-end 0)))
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(while (string-match "[^ ]+ " string)
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(let ((arg
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(substring string (match-beginning 0) (1- (match-end 0)))))
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(setq string (substring string (match-end 0)))
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(if (string-match "\\`\\+[0-9]+\\'" arg)
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(setq lineno (read (substring arg 1)))
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(setq files
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(cons (list arg lineno)
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files))
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(setq lineno 1))))
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(server-visit-files files client)
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;; CLIENT is now a list (CLIENTNUM BUFFERS...)
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(setq server-clients (cons client server-clients))
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(switch-to-buffer (nth 1 client))
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(message (substitute-command-keys
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"When done with a buffer, type \\[server-edit].")))))
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(defun server-visit-files (files client)
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"Finds FILES and returns the list CLIENT with the buffers nconc'd.
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FILES is an alist whose elements are (FILENAME LINENUMBER)."
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(let (client-record)
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(while files
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(save-excursion
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;; If there is an existing buffer modified or the file is modified,
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;; revert it.
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;; If there is an existing buffer with deleted file, offer to write it.
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(let* ((filen (car (car files)))
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(obuf (get-file-buffer filen)))
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(if (and obuf (set-buffer obuf))
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(if (file-exists-p filen)
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(if (or (not (verify-visited-file-modtime obuf))
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(buffer-modified-p obuf))
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(revert-buffer t nil))
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(if (y-or-n-p
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(concat "File no longer exists: "
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filen
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", write buffer to file? "))
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(write-file filen)))
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(set-buffer (find-file-noselect filen))
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(run-hooks 'server-visit-hook)))
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(goto-line (nth 1 (car files)))
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(setq server-buffer-clients (cons (car client) server-buffer-clients))
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(setq client-record (cons (current-buffer) client-record)))
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(setq files (cdr files)))
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(nconc client client-record)))
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(defun server-buffer-done (buffer)
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"Mark BUFFER as \"done\" for its client(s).
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Buries the buffer, and returns another server buffer
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as a suggestion for what to select next."
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(let ((running (eq (process-status server-process) 'run))
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(next-buffer nil)
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(old-clients server-clients))
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(while old-clients
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(let ((client (car old-clients)))
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(or next-buffer
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(setq next-buffer (nth 1 (memq buffer client))))
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(delq buffer client)
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;; If client now has no pending buffers,
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;; tell it that it is done, and forget it entirely.
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(if (cdr client) nil
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(if running
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(progn
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(send-string server-process
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(format "Close: %s Done\n" (car client)))
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(server-log (format "Close: %s Done\n" (car client)))))
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(setq server-clients (delq client server-clients))))
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(setq old-clients (cdr old-clients)))
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(if (buffer-name buffer)
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(save-excursion
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(set-buffer buffer)
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(setq server-buffer-clients nil)))
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(bury-buffer buffer)
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next-buffer))
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(defun server-temp-file-p (buffer)
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"Return non-nil if BUFFER contains a file considered temporary.
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These are files whose names suggest they are repeatedly
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reused to pass information to another program.
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The variable `server-temp-file-regexp' controls which filenames
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are considered temporary."
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(and (buffer-file-name buffer)
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(string-match server-temp-file-regexp (buffer-file-name buffer))))
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(defun server-done ()
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"Offer to save current buffer, mark it as \"done\" for clients,
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bury it, and return a suggested buffer to select next."
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(let ((buffer (current-buffer)))
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(if server-buffer-clients
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(progn
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(if (server-temp-file-p buffer)
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(progn (save-buffer)
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(write-region (point-min) (point-max)
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(concat buffer-file-name "~"))
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(kill-buffer buffer))
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(if (and (buffer-modified-p)
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(y-or-n-p (concat "Save file " buffer-file-name "? ")))
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(save-buffer buffer)))
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(server-buffer-done buffer)))))
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(defun server-edit (&optional arg)
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"Switch to next server editing buffer; say \"Done\" for current buffer.
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If a server buffer is current, it is marked \"done\" and optionally saved.
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When all of a client's buffers are marked as \"done\", the client is notified.
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Temporary files such as MH <draft> files are always saved and backed up,
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no questions asked. The variable `server-temp-file-regexp' controls
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which filenames are considered temporary.
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If invoked with a prefix argument, or if there is no server process running,
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starts server process and that is all. Invoked by \\[server-edit]."
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(interactive "P")
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(if (or arg
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(not server-process)
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(memq (process-status server-process) '(signal exit)))
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(server-start nil)
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(server-switch-buffer (server-done))))
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(defun server-switch-buffer (next-buffer)
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"Switch to another buffer, preferably one that has a client.
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Arg NEXT-BUFFER is a suggestion; if it is a live buffer, use it."
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(if next-buffer
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(if (and (bufferp next-buffer)
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(buffer-name next-buffer))
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(switch-to-buffer next-buffer)
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;; If NEXT-BUFFER is a dead buffer,
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;; remove the server records for it
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;; and try the next surviving server buffer.
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(server-switch-buffer
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(server-buffer-done next-buffer)))
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(if server-clients
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(server-switch-buffer (nth 1 (car server-clients)))
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(switch-to-buffer (other-buffer)))))
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(global-set-key "\C-x#" 'server-edit)
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(provide 'server)
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;;; server.el ends here
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