--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/gnus/gnus-demon.el	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,222 @@
+;;; gnus-demon.el --- daemonic Gnus behaviour
+;; Copyright (C) 1995,96 Free Software Foundation, Inc.
+
+;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
+;; 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.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'gnus)
+
+(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) 
+
+(eval-and-compile
+  (autoload 'timezone-parse-date "timezone")
+  (autoload 'timezone-make-arpa-date "timezone"))
+
+;;; Functions.
+
+(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.
+  (gnus-demon-remove-handler function)
+  ;; Then add the new one.
+  (push (list function time idle) gnus-demon-handlers)
+  (gnus-demon-init))
+
+(defun gnus-demon-remove-handler (function &optional no-init)
+  "Remove the handler FUNCTION from the list of handlers."
+  (setq gnus-demon-handlers 
+	(delq (assq function gnus-demon-handlers)
+	      gnus-demon-handlers))
+  (or no-init (gnus-demon-init)))
+
+(defun gnus-demon-init ()
+  "Initialize the Gnus daemon."
+  (interactive)
+  (gnus-demon-cancel)
+  (if (null gnus-demon-handlers)
+      () ; Nothing to do.
+    ;; Set up timer.
+    (setq gnus-demon-timer 
+	  (nnheader-run-at-time 
+	   gnus-demon-timestep gnus-demon-timestep 'gnus-demon))
+    ;; Reset control variables.
+    (setq gnus-demon-handler-state
+	  (mapcar 
+	   (lambda (handler)
+	     (list (car handler) (gnus-demon-time-to-step (nth 1 handler))
+		   (nth 2 handler)))
+	   gnus-demon-handlers))
+    (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."
+  (interactive)
+  (and gnus-demon-timer
+       (nnheader-cancel-timer gnus-demon-timer))
+  (setq gnus-demon-timer nil
+	gnus-use-demon 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)
+	(progn
+	  (setq gnus-demon-last-keys keys)
+	  nil))))
+
+(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))
+      time
+    (let* ((date (current-time-string))
+	   (dv (timezone-parse-date date))
+	   (tdate (timezone-make-arpa-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")))
+	   (nseconds (gnus-time-minus
+		      (gnus-encode-date tdate) (gnus-encode-date date))))
+      (round
+       (/ (if (< nseconds 0)
+	      (+ nseconds (* 60 60 24))
+	    nseconds) gnus-demon-timestep)))))
+
+(defun gnus-demon ()
+  "The Gnus daemon that takes care of running all Gnus handlers."
+  ;; Increase or reset the time Emacs has been idle.
+  (if (gnus-demon-is-idle-p)
+      (incf gnus-demon-idle-time)
+    (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)
+    (while handlers
+      (setq handler (pop handlers))
+      (cond 
+       ((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.
+	     (progn
+	       (funcall (car handler))
+	       ;; And reset the timer.
+	       (setcar (nthcdr 1 handler)
+		       (gnus-demon-time-to-step
+			(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)))
+       (t
+	;; 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)
+	     (progn
+	       (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."
+  (gnus-nocem-scan-groups))
+
+(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 ()
+  (gnus-close-backends))
+
+(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)
+	server)
+    (while (setq server (car (pop servers)))
+      (and (gnus-check-backend-function 'request-scan (car server))
+	   (or (gnus-server-opened server)
+	       (gnus-open-server server))
+	   (gnus-request-scan nil server)))))
+
+(provide 'gnus-demon)
+
+;;; gnus-demon.el ends here