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autosave.cpp Example File
demos/browser/autosave.cpp

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 #include "autosave.h"

 #include <QtCore/QDir>
 #include <QtCore/QCoreApplication>
 #include <QtCore/QMetaObject>
 #include <QtDebug>

 #define AUTOSAVE_IN  1000 * 3  // seconds
 #define MAXWAIT      1000 * 15 // seconds

 AutoSave::AutoSave(QObject *parent) : QObject(parent)
 {
     Q_ASSERT(parent);
 }

 AutoSave::~AutoSave()
 {
     if (m_timer.isActive())
         qWarning() << "AutoSave: still active when destroyed, changes not saved.";
 }

 void AutoSave::changed()
 {
     if (m_firstChange.isNull())
         m_firstChange.start();

     if (m_firstChange.elapsed() > MAXWAIT) {
         saveNow();
     } else {
         m_timer.start(AUTOSAVE_IN, this);
     }
 }

 void AutoSave::timerEvent(QTimerEvent *event)
 {
     if (event->timerId() == m_timer.timerId()) {
         saveNow();
     } else {
         QObject::timerEvent(event);
     }
 }

 void AutoSave::saveNow()
 {
     if (!m_timer.isActive())
         return;
     m_timer.stop();
     m_firstChange = QTime();
     if (!QMetaObject::invokeMethod(parent(), "save", Qt::DirectConnection)) {
         qWarning() << "AutoSave: error invoking slot save() on parent";
     }
 }


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Qt 4.4.0-beta1