autosaver.cpp Example File | Qt WebEngine 5.9

Qt 5.9 | Qt WebEngine | WebEngine Demo Browser Example | autosaver.cpp Example File

Qt 5.9.9 Reference Documentation

# autosaver.cpp Example File

webenginewidgets/demobrowser/autosaver.cpp

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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";
          }
      }