lisp/gnus-demon.el

   1 ;;; gnus-demon.el --- daemonic Gnus behaviour
   2 ;; Copyright (C) 1995,96 Free Software Foundation, Inc.
   3
   4 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
   5 ;; Keywords: news
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (require 'gnus)
  29
  30 (eval-when-compile (require 'cl))
  31
  32 (defvar gnus-demon-handlers nil
  33   "Alist of daemonic handlers to be run at intervals.
  34 Each handler is a list on the form
  35
  36 \(FUNCTION TIME IDLE)
  37
  38 FUNCTION is the function to be called.
  39 TIME is the number of `gnus-demon-timestep's between each call.
  40 If nil, never call.  If t, call each `gnus-demon-timestep'.
  41 If IDLE is t, only call if Emacs has been idle for a while.  If IDLE
  42 is a number, only call when Emacs has been idle more than this number
  43 of `gnus-demon-timestep's.  If IDLE is nil, don't care about
  44 idleness.  If IDLE is a number and TIME is nil, then call once each
  45 time Emacs has been idle for IDLE `gnus-demon-timestep's.")
  46
  47 (defvar gnus-demon-timestep 60
  48   "*Number of seconds in each demon timestep.")
  49
  50 ;;; Internal variables.
  51
  52 (defvar gnus-demon-timer nil)
  53 (defvar gnus-demon-idle-has-been-called nil)
  54 (defvar gnus-demon-idle-time 0)
  55 (defvar gnus-demon-handler-state nil)
  56 (defvar gnus-demon-is-idle nil)
  57 (defvar gnus-demon-last-keys nil)
  58
  59 (eval-and-compile
  60   (autoload 'timezone-parse-date "timezone")
  61   (autoload 'timezone-make-arpa-date "timezone"))
  62
  63 ;;; Functions.
  64
  65 (defun gnus-demon-add-handler (function time idle)
  66   "Add the handler FUNCTION to be run at TIME and IDLE."
  67   ;; First remove any old handlers that use this function.
  68   (gnus-demon-remove-handler function)
  69   ;; Then add the new one.
  70   (push (list function time idle) gnus-demon-handlers)
  71   (gnus-demon-init))
  72
  73 (defun gnus-demon-remove-handler (function &optional no-init)
  74   "Remove the handler FUNCTION from the list of handlers."
  75   (setq gnus-demon-handlers
  76         (delq (assq function gnus-demon-handlers)
  77               gnus-demon-handlers))
  78   (or no-init (gnus-demon-init)))
  79
  80 (defun gnus-demon-init ()
  81   "Initialize the Gnus daemon."
  82   (interactive)
  83   (gnus-demon-cancel)
  84   (if (null gnus-demon-handlers)
  85       () ; Nothing to do.
  86     ;; Set up timer.
  87     (setq gnus-demon-timer
  88           (nnheader-run-at-time
  89            gnus-demon-timestep gnus-demon-timestep 'gnus-demon))
  90     ;; Reset control variables.
  91     (setq gnus-demon-handler-state
  92           (mapcar
  93            (lambda (handler)
  94              (list (car handler) (gnus-demon-time-to-step (nth 1 handler))
  95                    (nth 2 handler)))
  96            gnus-demon-handlers))
  97     (setq gnus-demon-idle-time 0)
  98     (setq gnus-demon-idle-has-been-called nil)
  99     (setq gnus-use-demon t)))
 100
 101 (gnus-add-shutdown 'gnus-demon-cancel 'gnus)
 102
 103 (defun gnus-demon-cancel ()
 104   "Cancel any Gnus daemons."
 105   (interactive)
 106   (and gnus-demon-timer
 107        (nnheader-cancel-timer gnus-demon-timer))
 108   (setq gnus-demon-timer nil
 109         gnus-use-demon nil))
 110
 111 (defun gnus-demon-is-idle-p ()
 112   "Whether Emacs is idle or not."
 113   ;; We do this simply by comparing the 100 most recent keystrokes
 114   ;; with the ones we had last time.  If they are the same, one might
 115   ;; guess that Emacs is indeed idle.  This only makes sense if one
 116   ;; calls this function seldom -- like once a minute, which is what
 117   ;; we do here.
 118   (let ((keys (recent-keys)))
 119     (or (equal keys gnus-demon-last-keys)
 120         (progn
 121           (setq gnus-demon-last-keys keys)
 122           nil))))
 123
 124 (defun gnus-demon-time-to-step (time)
 125   "Find out how many seconds to TIME, which is on the form \"17:43\"."
 126   (if (not (stringp time))
 127       time
 128     (let* ((date (current-time-string))
 129            (dv (timezone-parse-date date))
 130            (tdate (timezone-make-arpa-date
 131                    (string-to-number (aref dv 0))
 132                    (string-to-number (aref dv 1))
 133                    (string-to-number (aref dv 2)) time
 134                    (or (aref dv 4) "UT")))
 135            (nseconds (gnus-time-minus
 136                       (gnus-encode-date tdate) (gnus-encode-date date))))
 137       (round
 138        (/ (if (< nseconds 0)
 139               (+ nseconds (* 60 60 24))
 140             nseconds) gnus-demon-timestep)))))
 141
 142 (defun gnus-demon ()
 143   "The Gnus daemon that takes care of running all Gnus handlers."
 144   ;; Increase or reset the time Emacs has been idle.
 145   (if (gnus-demon-is-idle-p)
 146       (incf gnus-demon-idle-time)
 147     (setq gnus-demon-idle-time 0)
 148     (setq gnus-demon-idle-has-been-called nil))
 149   ;; Then we go through all the handler and call those that are
 150   ;; sufficiently ripe.
 151   (let ((handlers gnus-demon-handler-state)
 152         handler time idle)
 153     (while handlers
 154       (setq handler (pop handlers))
 155       (cond
 156        ((numberp (setq time (nth 1 handler)))
 157         ;; These handlers use a regular timeout mechanism.  We decrease
 158         ;; the timer if it hasn't reached zero yet.
 159         (or (zerop time)
 160             (setcar (nthcdr 1 handler) (decf time)))
 161         (and (zerop time)               ; If the timer now is zero...
 162              (or (not (setq idle (nth 2 handler))) ; Don't care about idle.
 163                  (and (numberp idle)    ; Numerical idle...
 164                       (< idle gnus-demon-idle-time)) ; Idle timed out.
 165                  gnus-demon-is-idle)    ; Or just need to be idle.
 166              ;; So we call the handler.
 167              (progn
 168                (funcall (car handler))
 169                ;; And reset the timer.
 170                (setcar (nthcdr 1 handler)
 171                        (gnus-demon-time-to-step
 172                         (nth 1 (assq (car handler) gnus-demon-handlers)))))))
 173        ;; These are only supposed to be called when Emacs is idle.
 174        ((null (setq idle (nth 2 handler)))
 175         ;; We do nothing.
 176         )
 177        ((not (numberp idle))
 178         ;; We want to call this handler each and every time that
 179         ;; Emacs is idle.
 180         (funcall (car handler)))
 181        (t
 182         ;; We want to call this handler only if Emacs has been idle
 183         ;; for a specified number of timesteps.
 184         (and (not (memq (car handler) gnus-demon-idle-has-been-called))
 185              (< idle gnus-demon-idle-time)
 186              (progn
 187                (funcall (car handler))
 188                ;; Make sure the handler won't be called once more in
 189                ;; this idle-cycle.
 190                (push (car handler) gnus-demon-idle-has-been-called))))))))
 191
 192 (defun gnus-demon-add-nocem ()
 193   "Add daemonic NoCeM handling to Gnus."
 194   (gnus-demon-add-handler 'gnus-demon-scan-nocem 60 t))
 195
 196 (defun gnus-demon-scan-nocem ()
 197   "Scan NoCeM groups for NoCeM messages."
 198   (gnus-nocem-scan-groups))
 199
 200 (defun gnus-demon-add-disconnection ()
 201   "Add daemonic server disconnection to Gnus."
 202   (gnus-demon-add-handler 'gnus-demon-close-connections nil 30))
 203
 204 (defun gnus-demon-close-connections ()
 205   (gnus-close-backends))
 206
 207 (defun gnus-demon-add-scanmail ()
 208   "Add daemonic scanning of mail from the mail backends."
 209   (gnus-demon-add-handler 'gnus-demon-scan-mail 120 60))
 210
 211 (defun gnus-demon-scan-mail ()
 212   (let ((servers gnus-opened-servers)
 213         server)
 214     (while (setq server (car (pop servers)))
 215       (and (gnus-check-backend-function 'request-scan (car server))
 216            (or (gnus-server-opened server)
 217                (gnus-open-server server))
 218            (gnus-request-scan nil server)))))
 219
 220 (provide 'gnus-demon)
 221
 222 ;;; gnus-demon.el ends here