lisp/gnus/gnus-demon.el

   1 ;;; gnus-demon.el --- daemonic Gnus behavior
   2
   3 ;; Copyright (C) 1995-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; Keywords: news
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (eval-when-compile (require 'cl))
  28
  29 (require 'gnus)
  30 (require 'gnus-int)
  31 (require 'nnheader)
  32 (require 'nntp)
  33 (require 'nnmail)
  34
  35 (defgroup gnus-demon nil
  36   "Demonic behavior."
  37   :group 'gnus)
  38
  39 (defcustom gnus-demon-handlers nil
  40   "Alist of daemonic handlers to be run at intervals.
  41 Each handler is a list on the form
  42
  43 \(FUNCTION TIME IDLE)
  44
  45 FUNCTION is the function to be called.  TIME is the number of
  46 `gnus-demon-timestep's between each call.
  47 If nil, never call. If t, call each `gnus-demon-timestep'.
  48
  49 If IDLE is t, only call each time Emacs has been idle for TIME.
  50 If IDLE is a number, only call when Emacs has been idle more than
  51 this number of `gnus-demon-timestep's.
  52 If IDLE is nil, don't care about idleness.
  53 If IDLE is a number and TIME is nil, then call once each time
  54 Emacs has been idle for IDLE `gnus-demon-timestep's."
  55   :group 'gnus-demon
  56   :type '(repeat (list function
  57                        (choice :tag "Time"
  58                                (const :tag "never" nil)
  59                                (const :tag "one" t)
  60                                (integer :tag "steps" 1))
  61                        (choice :tag "Idle"
  62                                (const :tag "don't care" nil)
  63                                (const :tag "for a while" t)
  64                                (integer :tag "steps" 1)))))
  65
  66 (defcustom gnus-demon-timestep 60
  67   "Number of seconds in each demon timestep."
  68   :group 'gnus-demon
  69   :type 'integer)
  70
  71 ;;; Internal variables.
  72
  73 (defvar gnus-demon-timers nil
  74   "Plist of idle timers which are running.")
  75 (defvar gnus-inhibit-demon nil
  76   "If non-nil, no daemonic function will be run.")
  77
  78 ;;; Functions.
  79
  80 (defun gnus-demon-add-handler (function time idle)
  81   "Add the handler FUNCTION to be run at TIME and IDLE."
  82   ;; First remove any old handlers that use this function.
  83   (gnus-demon-remove-handler function)
  84   ;; Then add the new one.
  85   (push (list function time idle) gnus-demon-handlers)
  86   (gnus-demon-init))
  87
  88 (defun gnus-demon-remove-handler (function &optional no-init)
  89   "Remove the handler FUNCTION from the list of handlers."
  90   (gnus-alist-pull function gnus-demon-handlers)
  91   (unless no-init
  92     (gnus-demon-init)))
  93
  94 (defun gnus-demon-idle-since ()
  95   "Return the number of seconds since when Emacs is idle."
  96   (float-time (or (current-idle-time) '(0 0 0))))
  97
  98 (defun gnus-demon-run-callback (func &optional idle time special)
  99   "Run FUNC if Emacs has been idle for longer than IDLE seconds.
 100 If not, and a TIME is given, restart a new idle timer, so FUNC
 101 can be called at the next opportunity. Such a special idle run is
 102 marked with SPECIAL."
 103   (unless gnus-inhibit-demon
 104     (block run-callback
 105       (when (eq idle t)
 106         (setq idle 0.001))
 107       (cond (special
 108              (setq gnus-demon-timers
 109                    (plist-put gnus-demon-timers func
 110                               (run-with-timer time time 'gnus-demon-run-callback
 111                                               func idle time))))
 112             ((and idle (> idle (gnus-demon-idle-since)))
 113              (when time
 114                (nnheader-cancel-timer (plist-get gnus-demon-timers func))
 115                (setq gnus-demon-timers
 116                      (plist-put gnus-demon-timers func
 117                                 (run-with-idle-timer idle nil
 118                                                      'gnus-demon-run-callback
 119                                                      func idle time t))))
 120              (return-from run-callback)))
 121       (with-local-quit
 122         (ignore-errors
 123           (funcall func))))))
 124
 125 (defun gnus-demon-init ()
 126   "Initialize the Gnus daemon."
 127   (interactive)
 128   (gnus-demon-cancel)
 129   (dolist (handler gnus-demon-handlers)
 130     ;; Set up the timer.
 131     (let* ((func (nth 0 handler))
 132            (time (nth 1 handler))
 133            (idle (nth 2 handler))
 134            ;; Compute time according with timestep.
 135            ;; If t, replace by 1
 136            (time (cond ((eq time t)
 137                         gnus-demon-timestep)
 138                        ((null time)
 139                         nil)
 140                        ((stringp time)
 141                         (* (gnus-demon-time-to-step time) gnus-demon-timestep))
 142                        (t
 143                         (* time gnus-demon-timestep))))
 144            (idle (cond ((numberp idle)
 145                         (* idle gnus-demon-timestep))
 146                        ((and (eq idle t) (numberp time))
 147                         time)
 148                        (t
 149                         idle)))
 150
 151            (timer
 152             (cond
 153              ;; (func nil number)
 154              ;; Only call when Emacs has been idle for `idle'
 155              ((and (null time) (numberp idle))
 156               (run-with-idle-timer idle t 'gnus-demon-run-callback func))
 157              ;; (func number any)
 158              ;; Call every `time'
 159              ((integerp time)
 160               (run-with-timer time time 'gnus-demon-run-callback
 161                               func idle time))
 162              ;; (func string any)
 163              ((stringp time)
 164               (run-with-timer time (* 24 60 60) 'gnus-demon-run-callback
 165                               func idle)))))
 166       (when timer
 167         (setq gnus-demon-timers (plist-put gnus-demon-timers func timer))))))
 168
 169 (defun gnus-demon-time-to-step (time)
 170   "Find out how many steps to TIME, which is on the form \"17:43\"."
 171   (let* ((now (current-time))
 172          ;; obtain NOW as discrete components -- make a vector for speed
 173          (nowParts (decode-time now))
 174          ;; obtain THEN as discrete components
 175          (thenParts (parse-time-string time))
 176          (thenHour (elt thenParts 2))
 177          (thenMin (elt thenParts 1))
 178          ;; convert time as elements into number of seconds since EPOCH.
 179          (then (encode-time 0
 180                             thenMin
 181                             thenHour
 182                             ;; If THEN is earlier than NOW, make it
 183                             ;; same time tomorrow.  Doc for encode-time
 184                             ;; says that this is OK.
 185                             (+ (elt nowParts 3)
 186                                (if (or (< thenHour (elt nowParts 2))
 187                                        (and (= thenHour (elt nowParts 2))
 188                                             (<= thenMin (elt nowParts 1))))
 189                                    1 0))
 190                             (elt nowParts 4)
 191                             (elt nowParts 5)
 192                             (elt nowParts 6)
 193                             (elt nowParts 7)
 194                             (elt nowParts 8)))
 195          ;; calculate number of seconds between NOW and THEN
 196          (diff (+ (* 65536 (- (car then) (car now)))
 197                   (- (cadr then) (cadr now)))))
 198     ;; return number of timesteps in the number of seconds
 199     (round (/ diff gnus-demon-timestep))))
 200
 201 (gnus-add-shutdown 'gnus-demon-cancel 'gnus)
 202
 203 (defun gnus-demon-cancel ()
 204   "Cancel any Gnus daemons."
 205   (interactive)
 206   (dotimes (i (/ (length gnus-demon-timers) 2))
 207     (nnheader-cancel-timer (nth (1+ (* i 2)) gnus-demon-timers)))
 208   (setq gnus-demon-timers nil))
 209
 210 (defun gnus-demon-add-disconnection ()
 211   "Add daemonic server disconnection to Gnus."
 212   (gnus-demon-add-handler 'gnus-demon-close-connections nil 30))
 213
 214 (defun gnus-demon-close-connections ()
 215   (save-window-excursion
 216     (gnus-close-backends)))
 217
 218 (defun gnus-demon-add-nntp-close-connection ()
 219   "Add daemonic nntp server disconnection to Gnus.
 220 If no commands have gone out via nntp during the last five
 221 minutes, the connection is closed."
 222   (gnus-demon-add-handler 'gnus-demon-nntp-close-connection 5 nil))
 223
 224 (defun gnus-demon-nntp-close-connection ()
 225   (save-window-excursion
 226     (when (time-less-p '(0 300) (time-since nntp-last-command-time))
 227       (nntp-close-server))))
 228
 229 (defun gnus-demon-add-scanmail ()
 230   "Add daemonic scanning of mail from the mail backends."
 231   (gnus-demon-add-handler 'gnus-demon-scan-mail 120 60))
 232
 233 (defun gnus-demon-scan-mail ()
 234   (save-window-excursion
 235     (let ((servers gnus-opened-servers)
 236           server
 237           (nnmail-fetched-sources (list t)))
 238       (while (setq server (car (pop servers)))
 239         (and (gnus-check-backend-function 'request-scan (car server))
 240              (or (gnus-server-opened server)
 241                  (gnus-open-server server))
 242              (gnus-request-scan nil server))))))
 243
 244 (defun gnus-demon-add-rescan ()
 245   "Add daemonic scanning of new articles from all backends."
 246   (gnus-demon-add-handler 'gnus-demon-scan-news 120 60))
 247
 248 (defun gnus-demon-scan-news ()
 249   (let ((win (current-window-configuration)))
 250     (unwind-protect
 251         (save-window-excursion
 252           (when (gnus-alive-p)
 253             (with-current-buffer gnus-group-buffer
 254               (gnus-group-get-new-news))))
 255       (set-window-configuration win))))
 256
 257 (defun gnus-demon-add-scan-timestamps ()
 258   "Add daemonic updating of timestamps in empty newgroups."
 259   (gnus-demon-add-handler 'gnus-demon-scan-timestamps nil 30))
 260
 261 (defun gnus-demon-scan-timestamps ()
 262   "Set the timestamp on all newsgroups with no unread and no ticked articles."
 263   (when (gnus-alive-p)
 264     (let ((cur-time (current-time))
 265           (newsrc (cdr gnus-newsrc-alist))
 266           info group unread has-ticked)
 267       (while (setq info (pop newsrc))
 268         (setq group (gnus-info-group info)
 269               unread (gnus-group-unread group)
 270               has-ticked (cdr (assq 'tick (gnus-info-marks info))))
 271         (when (and (numberp unread)
 272                    (= unread 0)
 273                    (not has-ticked))
 274           (gnus-group-set-parameter group 'timestamp cur-time))))))
 275
 276 (provide 'gnus-demon)
 277
 278 ;;; gnus-demon.el ends here