;;; gnus-demon.el --- daemonic Gnus behaviour
;; Copyright (C) 1995,96 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <firstname.lastname@example.org>
;; Keywords: news
;; 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 2, 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
(eval-when-compile (require 'cl))
(defvar gnus-demon-handlers nil
"Alist of daemonic handlers to be run at intervals.
Each handler is a list on the form
\(FUNCTION TIME IDLE)
FUNCTION is the function to be called.
TIME is the number of `gnus-demon-timestep's between each call.
If nil, never call. If t, call each `gnus-demon-timestep'.
If IDLE is t, only call if Emacs has been idle for a while. If IDLE
is a number, only call when Emacs has been idle more than this number
of `gnus-demon-timestep's. If IDLE is nil, don't care about
idleness. If IDLE is a number and TIME is nil, then call once each
time Emacs has been idle for IDLE `gnus-demon-timestep's.")
(defvar gnus-demon-timestep 60
"*Number of seconds in each demon timestep.")
;;; Internal variables.
(defvar gnus-demon-timer nil)
(defvar gnus-demon-idle-has-been-called nil)
(defvar gnus-demon-idle-time 0)
(defvar gnus-demon-handler-state nil)
(defvar gnus-demon-is-idle nil)
(defvar gnus-demon-last-keys nil)
(autoload 'timezone-parse-date "timezone")
(autoload 'timezone-make-arpa-date "timezone"))
(defun gnus-demon-add-handler (function time idle)
"Add the handler FUNCTION to be run at TIME and IDLE."
;; First remove any old handlers that use this function.
;; Then add the new one.
(push (list function time idle) gnus-demon-handlers)
(defun gnus-demon-remove-handler (function &optional no-init)
"Remove the handler FUNCTION from the list of handlers."
(delq (assq function gnus-demon-handlers)
(or no-init (gnus-demon-init)))
(defun gnus-demon-init ()
"Initialize the Gnus daemon."
(if (null gnus-demon-handlers)
() ; Nothing to do.
;; Set up timer.
gnus-demon-timestep gnus-demon-timestep 'gnus-demon))
;; Reset control variables.
(list (car handler) (gnus-demon-time-to-step (nth 1 handler))
(nth 2 handler)))
(setq gnus-demon-idle-time 0)
(setq gnus-demon-idle-has-been-called nil)
(setq gnus-use-demon t)))
(gnus-add-shutdown 'gnus-demon-cancel 'gnus)
(defun gnus-demon-cancel ()
"Cancel any Gnus daemons."
(setq gnus-demon-timer nil
(defun gnus-demon-is-idle-p ()
"Whether Emacs is idle or not."
;; We do this simply by comparing the 100 most recent keystrokes
;; with the ones we had last time. If they are the same, one might
;; guess that Emacs is indeed idle. This only makes sense if one
;; calls this function seldom -- like once a minute, which is what
;; we do here.
(let ((keys (recent-keys)))
(or (equal keys gnus-demon-last-keys)
(setq gnus-demon-last-keys keys)
(defun gnus-demon-time-to-step (time)
"Find out how many seconds to TIME, which is on the form \"17:43\"."
(if (not (stringp time))
(let* ((date (current-time-string))
(dv (timezone-parse-date date))
(string-to-number (aref dv 0))
(string-to-number (aref dv 1))
(string-to-number (aref dv 2)) time
(or (aref dv 4) "UT")))
(gnus-encode-date tdate) (gnus-encode-date date))))
(/ (if (< nseconds 0)
(+ nseconds (* 60 60 24))
(defun gnus-demon ()
"The Gnus daemon that takes care of running all Gnus handlers."
;; Increase or reset the time Emacs has been idle.
(setq gnus-demon-idle-time 0)
(setq gnus-demon-idle-has-been-called nil))
;; Then we go through all the handler and call those that are
;; sufficiently ripe.
(let ((handlers gnus-demon-handler-state)
handler time idle)
(setq handler (pop handlers))
((numberp (setq time (nth 1 handler)))
;; These handlers use a regular timeout mechanism. We decrease
;; the timer if it hasn't reached zero yet.
(or (zerop time)
(setcar (nthcdr 1 handler) (decf time)))
(and (zerop time) ; If the timer now is zero...
(or (not (setq idle (nth 2 handler))) ; Don't care about idle.
(and (numberp idle) ; Numerical idle...
(< idle gnus-demon-idle-time)) ; Idle timed out.
gnus-demon-is-idle) ; Or just need to be idle.
;; So we call the handler.
(funcall (car handler))
;; And reset the timer.
(setcar (nthcdr 1 handler)
(nth 1 (assq (car handler) gnus-demon-handlers)))))))
;; These are only supposed to be called when Emacs is idle.
((null (setq idle (nth 2 handler)))
;; We do nothing.
((not (numberp idle))
;; We want to call this handler each and every time that
;; Emacs is idle.
(funcall (car handler)))
;; We want to call this handler only if Emacs has been idle
;; for a specified number of timesteps.
(and (not (memq (car handler) gnus-demon-idle-has-been-called))
(< idle gnus-demon-idle-time)
(funcall (car handler))
;; Make sure the handler won't be called once more in
;; this idle-cycle.
(push (car handler) gnus-demon-idle-has-been-called))))))))
(defun gnus-demon-add-nocem ()
"Add daemonic NoCeM handling to Gnus."
(gnus-demon-add-handler 'gnus-demon-scan-nocem 60 t))
(defun gnus-demon-scan-nocem ()
"Scan NoCeM groups for NoCeM messages."
(defun gnus-demon-add-disconnection ()
"Add daemonic server disconnection to Gnus."
(gnus-demon-add-handler 'gnus-demon-close-connections nil 30))
(defun gnus-demon-close-connections ()
(defun gnus-demon-add-scanmail ()
"Add daemonic scanning of mail from the mail backends."
(gnus-demon-add-handler 'gnus-demon-scan-mail 120 60))
(defun gnus-demon-scan-mail ()
(let ((servers gnus-opened-servers)
(while (setq server (car (pop servers)))
(and (gnus-check-backend-function 'request-scan (car server))
(or (gnus-server-opened server)
(gnus-request-scan nil server)))))
;;; gnus-demon.el ends here