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comparison lisp/prim/itimer-autosave.el @ 26:441bb1e64a06 r19-15b96

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Import from CVS: tag r19-15b96
author cvs
date Mon, 13 Aug 2007 08:51:32 +0200
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25:383a494979f8 26:441bb1e64a06
1 ;;; itimer-autosave.el --- Autosave functions with itimers
2
3 ;; Copyright status unknown
4
5 ;; This file is part of XEmacs.
6
7 ;; XEmacs is free software; you can redistribute it and/or modify it
8 ;; under the terms of the GNU General Public License as published by
9 ;; the Free Software Foundation; either version 2, or (at your option)
10 ;; any later version.
11
12 ;; XEmacs is distributed in the hope that it will be useful, but
13 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
14 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 ;; General Public License for more details.
16
17 ;; You should have received a copy of the GNU General Public License
18 ;; along with XEmacs; see the file COPYING. If not, write to the Free
19 ;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
20 ;; 02111-1307, USA.
21
22 ;;; Synched up with: Not in FSF.
23
24 ;;; Commentary:
25
26 ;; itimer-driven auto-saves
27
28 ;;; Code:
29
30 ;jwz: this is preloaded so don't ;;;###autoload
31 (defvar auto-save-timeout 960
32 "*Number of seconds idle time before auto-save.
33 Zero or nil means disable auto-saving due to idleness.
34
35 The actual amount of idle time between auto-saves is logarithmically related
36 to the size of the current buffer. This variable is the number of seconds
37 after which an auto-save will happen when the current buffer is 50k or less;
38 the timeout will be 2 1/4 times this in a 200k buffer, 3 3/4 times this in a
39 1000k buffer, and 4 1/2 times this in a 2000k buffer.
40
41 See also the variable `auto-save-interval', which controls auto-saving based
42 on the number of characters typed.")
43
44 ;jwz: this is preloaded so don't ;;;###autoload
45 (defvar auto-gc-threshold (/ gc-cons-threshold 3)
46 "*GC when this many bytes have been consed since the last GC,
47 and the user has been idle for `auto-save-timeout' seconds.")
48
49 (defun auto-save-itimer ()
50 "For use as a itimer callback function.
51 Auto-saves and garbage-collects based on the size of the current buffer
52 and the value of `auto-save-timeout', `auto-gc-threshold', and the current
53 keyboard idle-time."
54 (if (or (null auto-save-timeout)
55 (<= auto-save-timeout 0)
56 (eq (minibuffer-window) (selected-window)))
57 nil
58 (let ((buf-size (1+ (ash (buffer-size) -8)))
59 (delay-level 0)
60 (now (current-time))
61 delay)
62 (while (> buf-size 64)
63 (setq delay-level (1+ delay-level)
64 buf-size (- buf-size (ash buf-size -2))))
65 (if (< delay-level 4)
66 (setq delay-level 4))
67 ;; delay_level is 4 for files under around 50k, 7 at 100k, 9 at 200k,
68 ;; 11 at 300k, and 12 at 500k, 15 at 1 meg, and 17 at 2 meg.
69 (setq delay (/ (* delay-level auto-save-timeout) 4))
70 (let ((idle-time (if (or (not (consp last-input-time))
71 (/= (car now) (car last-input-time)))
72 (1+ delay)
73 (- (car (cdr now)) (cdr last-input-time)))))
74 (and (> idle-time delay)
75 (do-auto-save))
76 (and (> idle-time auto-save-timeout)
77 (> (consing-since-gc) auto-gc-threshold)
78 (garbage-collect)))))
79 ;; Look at the itimer that's currently running; if the user has changed
80 ;; the value of auto-save-timeout, modify this itimer to have the correct
81 ;; restart time. There will be some latency between when the user changes
82 ;; this variable and when it takes effect, but it will happen eventually.
83 (let ((self (get-itimer "auto-save")))
84 (or self (error "auto-save-itimer can't find itself"))
85 (if (and auto-save-timeout (> auto-save-timeout 4))
86 (or (= (itimer-restart self) (/ auto-save-timeout 4))
87 (set-itimer-restart self (/ auto-save-timeout 4)))))
88 nil)
89
90 (defun itimer-init-auto-gc ()
91 (or noninteractive ; may be being run from after-init-hook in -batch mode.
92 (get-itimer "auto-save")
93 ;; the time here is just the first interval; if the user changes it
94 ;; later, it will adjust.
95 (let ((time (max 2 (/ (or auto-save-timeout 30) 4))))
96 (start-itimer "auto-save" 'auto-save-itimer time time))))
97
98 (cond (purify-flag
99 ;; This file is being preloaded into an emacs about to be dumped.
100 ;; So arrange for the auto-save itimer to be started once emacs
101 ;; is launched.
102 (add-hook 'after-init-hook 'itimer-init-auto-gc))
103 (t
104 ;; Otherwise, this file is being loaded into a normal, interactive
105 ;; emacs. Start the auto-save timer now.
106 (itimer-init-auto-gc)))
107
108
109 ;;; itimer-autosave.el ends here