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#include "qvaluespacemanager_p.h"
#include "gconflayer_p.h"
#include "registrylayer_win_p.h"

#include <QtCore/qmutex.h>
#include <QtCore/qthread.h>
#include <QtCore/private/qcoreapplication_p.h>

QT_BEGIN_NAMESPACE

static QBasicAtomicPointer<QValueSpaceManager> valueSpaceManager_ptr;

QValueSpaceManager *QValueSpaceManager::instance()
{
    QValueSpaceManager *ptr = valueSpaceManager_ptr.loadAcquire();
    if (!ptr) {
        static QBasicMutex valueSpaceManager_mutex;
        QMutexLocker locker(&valueSpaceManager_mutex);
        if (!(ptr = valueSpaceManager_ptr.loadAcquire())) {
            ptr = new QValueSpaceManager;

            // make sure layers are installed in the priority order from high to low
#if defined(Q_OS_LINUX)
#if !defined(QT_NO_GCONFLAYER)
            ptr->layers.append(GConfLayer::instance());
#endif
#elif defined(Q_OS_WIN)
            ptr->layers.append(NonVolatileRegistryLayer::instance());
            ptr->layers.append(VolatileRegistryLayer::instance());
#endif

            // move all layers to a worker thread
            if (ptr->layers.size() > 0) {
                QThread *valueSpaceThread = new QThread();
                valueSpaceThread->setObjectName(QStringLiteral("valueSpaceThread"));
                valueSpaceThread->moveToThread(QCoreApplicationPrivate::mainThread());
                for (int i = 0; i < ptr->layers.size(); ++i)
                    ptr->layers[i]->moveToThread(valueSpaceThread);
                valueSpaceThread->start();
            }

            valueSpaceManager_ptr.storeRelease(ptr);
        }
    }
    return ptr;
}

QValueSpaceManager::QValueSpaceManager()
{
}

QList<QAbstractValueSpaceLayer *> const &QValueSpaceManager::getLayers()
{
    return layers;
}

QT_END_NAMESPACE