dictionary / connection.el

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;;; connection.el -- handling a tcp based connection

;; Author: Torsten Hilbrich <>
;; Keywords: network
;; $Id$

;; This file 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 2, or (at your option)
;; any later version.

;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

  (require 'cl))

(defcustom connection-broken-end-of-line
  "Set to t (on) if you use a MULE Emacsen and have problems while connecting.
Usually for the dict protocol, the end of line characters are \\r\\n.
However, some users reported problems with using Emacs 20.3 and MULE
which seems to convert the \\r\\n to \\n while inserting the text into
the buffer.  If you encounter these problems please set the value to t
and try again.
  :group 'dictionary
  :type 'boolean)

(defmacro connection-p (connection)
  "Returns non-nil if `connection' is a connection object"
  (list 'get connection ''connection))

(defmacro connection-read-point (connection)
  "Return the read point of the connection object."
  (list 'get connection ''connection-read-point))

(defmacro connection-process (connection)
  "Return the process of the connection object."
  (list 'get connection ''connection-process))

(defmacro connection-buffer (connection)
  "Return the buffer of the connection object."
  (list 'get connection ''connection-buffer))

(defmacro connection-set-read-point (connection point)
  "Set the read-point for `connection' to `point'."
  (list 'put connection ''connection-read-point point))

(defmacro connection-set-process (connection process)
  "Set the process for `connection' to `process'."
  (list 'put connection ''connection-process process))

(defmacro connection-set-buffer (connection buffer)
  "Set the buffer for `connection' to `buffer'."
  (list 'put connection ''connection-buffer buffer))

(defun connection-create-data (buffer process point)
  "Create a new connection data based on `buffer', `process', and `point'."
  (let ((connection (make-symbol "connection")))
    (put connection 'connection t)
    (connection-set-read-point connection point)
    (connection-set-process connection process)
    (connection-set-buffer connection buffer)

(defun connection-open (server port)
  "Open a connection to `server' and `port'.
A data structure identifing the connection is returned"

  (let ((process-buffer (generate-new-buffer (format " connection to %s:%s"
      (set-buffer process-buffer)
      (setq process (open-network-stream "connection" process-buffer
					 server port))
      (connection-create-data process-buffer process (point-min)))))

(defun connection-status (connection)
  "Return the status of the connection.
Possible return values are the symbols:
nil: argument is no connection object
'none: argument has no connection
'up: connection is open and buffer is existing
'down: connection is closed
'alone: connection is not associated with a buffer"
  (if (connection-p connection)
      (let ((process (connection-process connection))
	    (buffer (connection-buffer connection)))
	(if (not process)
	  (if (not (buffer-live-p buffer))
	    (if (not (eq (process-status process) 'open))

(defun connection-close (connection)
  "Force closing of the connection."
  (if (connection-p connection)
	(let ((buffer (connection-buffer connection))
	      (process (connection-process connection)))
	  (if process
	      (delete-process process))
	  (if buffer
	      (kill-buffer buffer))
	  (connection-set-process connection nil)
	  (connection-set-buffer connection nil)))))

(defun connection-send (connection data)
  "Send `data' to the process."
  (unless (eq (connection-status connection) 'up)
    (error "Connection is not up"))
    (set-buffer (connection-buffer connection))
    (goto-char (point-max))
    (connection-set-read-point connection (point))
    (process-send-string (connection-process connection) data)))

(defun connection-send-crlf (connection data)
  "Send `data' together with CRLF to the process."
  (connection-send connection (concat data "\r\n")))

(defun connection-read (connection delimiter)
  "Read data until `delimiter' is found inside the buffer."
  (unless (eq (connection-status connection) 'up)
    (error "Connection is not up"))
  (let ((case-fold-search nil)
      (set-buffer (connection-buffer connection))
      (goto-char (connection-read-point connection))
      ;; Wait until there is enough data 
      (while (not (search-forward delimiter nil t))
	(accept-process-output (connection-process connection) 3)
	(goto-char (connection-read-point connection)))
      (setq match-end (point))
      ;; Return the result
      (let ((result (buffer-substring (connection-read-point connection)
	(connection-set-read-point connection match-end)

(defun connection-read-crlf (connection)
  "Read until a line is completedx with CRLF"
  (connection-read connection (if connection-broken-end-of-line

(defun connection-read-to-point (connection)
  "Read until a line is consisting of a single point"
  (connection-read connection (if connection-broken-end-of-line

(provide 'connection)