singleton.h


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#pragma once

// qt
#include <QMutex>
#include <QSharedPointer>

#define SINGLETON(type) Singleton<type>::get().data()

template <class T> class Singleton
{
public:
    static QSharedPointer<T> get()
    {
        static QMutex mtx;
        QMutexLocker l(&mtx);

        if (!m_instance)
        {
            m_instance.reset(
                static_cast<T*>(T::staticMetaObject.newInstance())
                // FIXME: deleteLater doesn't work. Crashes without it
                ,
                &T::deleteLater
            );
        }

        return m_instance;
    }
    static void cleanup()
    {
        static QMutex mtx;
        QMutexLocker l(&mtx);

        m_instance.clear();
    }

    typedef QSharedPointer<T> FactorySharedPointer;

private:
    static FactorySharedPointer m_instance;
};

template <class T>
typename Singleton<T>::FactorySharedPointer Singleton<T>::m_instance;