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comparison lisp/itimer-autosave.el @ 209:41ff10fd062f r20-4b3

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Import from CVS: tag r20-4b3
author cvs
date Mon, 13 Aug 2007 10:04:58 +0200
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children 308d34e9f07d
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208:f427b8ec4379 209:41ff10fd062f
1 ;;; itimer-autosave.el --- Autosave functions with itimers
2
3 ;; Copyright status unknown
4
5 ;; Maintainer: XEmacs Development Team
6 ;; Keywords: internal, dumped
7
8 ;; This file is part of XEmacs.
9
10 ;; XEmacs is free software; you can redistribute it and/or modify it
11 ;; under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
13 ;; any later version.
14
15 ;; XEmacs is distributed in the hope that it will be useful, but
16 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 ;; General Public License for more details.
19
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with XEmacs; see the file COPYING. If not, write to the Free
22 ;; Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 ;; 02111-1307, USA.
24
25 ;;; Synched up with: Not in FSF.
26
27 ;;; Commentary:
28
29 ;; This file is dumped with XEmacs.
30
31 ;; itimer-driven auto-saves
32
33 ;;; Code:
34
35 ;jwz: this is preloaded so don't ;;;###autoload
36 (defvar auto-save-timeout 960
37 "*Number of seconds idle time before auto-save.
38 Zero or nil means disable auto-saving due to idleness.
39
40 The actual amount of idle time between auto-saves is logarithmically related
41 to the size of the current buffer. This variable is the number of seconds
42 after which an auto-save will happen when the current buffer is 50k or less;
43 the timeout will be 2 1/4 times this in a 200k buffer, 3 3/4 times this in a
44 1000k buffer, and 4 1/2 times this in a 2000k buffer.
45
46 See also the variable `auto-save-interval', which controls auto-saving based
47 on the number of characters typed.")
48
49 ;jwz: this is preloaded so don't ;;;###autoload
50 (defvar auto-gc-threshold (/ gc-cons-threshold 3)
51 "*GC when this many bytes have been consed since the last GC,
52 and the user has been idle for `auto-save-timeout' seconds.")
53
54 (defun auto-save-itimer ()
55 "For use as a itimer callback function.
56 Auto-saves and garbage-collects based on the size of the current buffer
57 and the value of `auto-save-timeout', `auto-gc-threshold', and the current
58 keyboard idle-time."
59 (if (or (null auto-save-timeout)
60 (<= auto-save-timeout 0)
61 (eq (minibuffer-window) (selected-window)))
62 nil
63 (let ((buf-size (1+ (ash (buffer-size) -8)))
64 (delay-level 0)
65 (now (current-time))
66 delay)
67 (while (> buf-size 64)
68 (setq delay-level (1+ delay-level)
69 buf-size (- buf-size (ash buf-size -2))))
70 (if (< delay-level 4)
71 (setq delay-level 4))
72 ;; delay_level is 4 for files under around 50k, 7 at 100k, 9 at 200k,
73 ;; 11 at 300k, and 12 at 500k, 15 at 1 meg, and 17 at 2 meg.
74 (setq delay (/ (* delay-level auto-save-timeout) 4))
75 (let ((idle-time (if (or (not (consp last-input-time))
76 (/= (car now) (car last-input-time)))
77 (1+ delay)
78 (- (car (cdr now)) (cdr last-input-time)))))
79 (and (> idle-time delay)
80 (do-auto-save))
81 (and (> idle-time auto-save-timeout)
82 (> (consing-since-gc) auto-gc-threshold)
83 (garbage-collect)))))
84 ;; Look at the itimer that's currently running; if the user has changed
85 ;; the value of auto-save-timeout, modify this itimer to have the correct
86 ;; restart time. There will be some latency between when the user changes
87 ;; this variable and when it takes effect, but it will happen eventually.
88 (let ((self (get-itimer "auto-save")))
89 (or self (error "auto-save-itimer can't find itself"))
90 (if (and auto-save-timeout (> auto-save-timeout 4))
91 (or (= (itimer-restart self) (/ auto-save-timeout 4))
92 (set-itimer-restart self (/ auto-save-timeout 4)))))
93 nil)
94
95 (defun itimer-init-auto-gc ()
96 (or noninteractive ; may be being run from after-init-hook in -batch mode.
97 (get-itimer "auto-save")
98 ;; the time here is just the first interval; if the user changes it
99 ;; later, it will adjust.
100 (let ((time (max 2 (/ (or auto-save-timeout 30) 4))))
101 (start-itimer "auto-save" 'auto-save-itimer time time))))
102
103 (cond (purify-flag
104 ;; This file is being preloaded into an emacs about to be dumped.
105 ;; So arrange for the auto-save itimer to be started once emacs
106 ;; is launched.
107 (add-hook 'after-init-hook 'itimer-init-auto-gc))
108 (t
109 ;; Otherwise, this file is being loaded into a normal, interactive
110 ;; emacs. Start the auto-save timer now.
111 (itimer-init-auto-gc)))
112
113
114 ;;; itimer-autosave.el ends here