autosaver.cpp Example File

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#include "autosaver.h"
#include <QtCore/QDir>
#include <QtCore/QCoreApplication>
#include <QtCore/QMetaObject>
#include <QtDebug>
#define AUTOSAVE_IN  1000 * 3  // seconds
#define MAXWAIT      1000 * 15 // seconds
AutoSaver::AutoSaver(QObject *parent) : QObject(parent)
{
    Q_ASSERT(parent);
}
AutoSaver::~AutoSaver()
{
    if (m_timer.isActive())
        qWarning() << "AutoSaver: still active when destroyed, changes not saved.";
}
void AutoSaver::changeOccurred()
{
    if (m_firstChange.isNull())
        m_firstChange.start();
    if (m_firstChange.elapsed() > MAXWAIT) {
        saveIfNeccessary();
    } else {
        m_timer.start(AUTOSAVE_IN, this);
    }
}
void AutoSaver::timerEvent(QTimerEvent *event)
{
    if (event->timerId() == m_timer.timerId()) {
        saveIfNeccessary();
    } else {
        QObject::timerEvent(event);
    }
}
void AutoSaver::saveIfNeccessary()
{
    if (!m_timer.isActive())
        return;
    m_timer.stop();
    m_firstChange = QTime();
    if (!QMetaObject::invokeMethod(parent(), "save", Qt::DirectConnection)) {
        qWarning() << "AutoSaver: error invoking slot save() on parent";
    }
}