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comparison demos/browser/autosaver.d @ 45:71b382c10ef6

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add coarse and incomplete QT browser port
author mandel
date Sun, 17 May 2009 18:49:59 +0000
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children 7bfd46c330dc
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44:3cb15c92ac28 45:71b382c10ef6
1 /****************************************************************************
2 **
3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
4 ** Contact: Qt Software Information (qt-info@nokia.com)
5 **
6 ** This file is part of the demonstration applications of the Qt Toolkit.
7 **
8 ** $QT_BEGIN_LICENSE:LGPL$
9 ** Commercial Usage
10 ** Licensees holding valid Qt Commercial licenses may use this file in
11 ** accordance with the Qt Commercial License Agreement provided with the
12 ** Software or, alternatively, in accordance with the terms contained in
13 ** a written agreement between you and Nokia.
14 **
15 ** GNU Lesser General Public License Usage
16 ** Alternatively, this file may be used under the terms of the GNU Lesser
17 ** General Public License version 2.1 as published by the Free Software
18 ** Foundation and appearing in the file LICENSE.LGPL included in the
19 ** packaging of this file. Please review the following information to
20 ** ensure the GNU Lesser General Public License version 2.1 requirements
21 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
22 **
23 ** In addition, as a special exception, Nokia gives you certain
24 ** additional rights. These rights are described in the Nokia Qt LGPL
25 ** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
26 ** package.
27 **
28 ** GNU General Public License Usage
29 ** Alternatively, this file may be used under the terms of the GNU
30 ** General Public License version 3.0 as published by the Free Software
31 ** Foundation and appearing in the file LICENSE.GPL included in the
32 ** packaging of this file. Please review the following information to
33 ** ensure the GNU General Public License version 3.0 requirements will be
34 ** met: http://www.gnu.org/copyleft/gpl.html.
35 **
36 ** If you are unsure which license is appropriate for your use, please
37 ** contact the sales department at qt-sales@nokia.com.
38 ** $QT_END_LICENSE$
39 **
40 ****************************************************************************/
41 module autosaver;
42
43 import QtCore.QObject;
44 import QtCore.QBasicTimer;
45 import QtCore.QTime;
46
47 import QtCore.QDir;
48 import QtCore.QCoreApplication;
49 import QtCore.QMetaObject;
50 import QtDebug;
51
52 const uint AUTOSAVE_IN = 1000 * 3 // seconds
53 const uint MAXWAIT = 1000 * 15 // seconds
54
55 /*
56 This class will call the save() slot on the parent object when the parent changes.
57 It will wait several seconds after changed() to combining multiple changes and
58 prevent continuous writing to disk.
59 */
60 class AutoSaver : public QObject {
61
62 Q_OBJECT
63
64 public:
65 this(QObject *parent)
66 {
67 super(parent);
68 Q_ASSERT(parent);
69 }
70 ~this();
71 {
72 if (m_timer.isActive())
73 qWarning() << "AutoSaver: still active when destroyed, changes not saved.";
74 }
75 void saveIfNeccessary()
76 {
77 if (!m_timer.isActive())
78 return;
79 m_timer.stop();
80 m_firstChange = QTime();
81 if (!QMetaObject::invokeMethod(parent(), "save", Qt::DirectConnection)) {
82 qWarning() << "AutoSaver: error invoking slot save() on parent";
83 }
84 }
85
86 public slots:
87 void changeOccurred();
88 {
89 if (m_firstChange.isNull())
90 m_firstChange.start();
91
92 if (m_firstChange.elapsed() > MAXWAIT) {
93 saveIfNeccessary();
94 } else {
95 m_timer.start(AUTOSAVE_IN, this);
96 }
97 }
98
99 protected:
100 void timerEvent(QTimerEvent *event)
101 {
102 if (event.timerId() == m_timer.timerId()) {
103 saveIfNeccessary();
104 } else {
105 QObject::timerEvent(event);
106 }
107 }
108
109
110 private:
111 QBasicTimer m_timer;
112 QTime m_firstChange;
113 }
114