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****************************************************************************/

#ifndef GCONFLAYER_H
#define GCONFLAYER_H

#include "qvaluespace_p.h"
#include "qvaluespacepublisher.h"

#include <QSet>
#include "gconfitem_p.h"
#include <QMutex>

QTM_BEGIN_NAMESPACE

class GConfLayer : public QAbstractValueSpaceLayer
{
    Q_OBJECT

public:
    GConfLayer();
    virtual ~GConfLayer();

protected:
    /*virtual*/ QString name();

    /*virtual*/ bool startup(Type type);

    /*virtual*/ QUuid id();
    /*virtual*/ unsigned int order();

    /*virtual*/ Handle item(Handle parent, const QString &subPath);
    /*virtual*/ void removeHandle(Handle handle);
    /*virtual*/ void setProperty(Handle handle, Properties properties);

    /*virtual*/ bool value(Handle handle, QVariant *data);
    /*virtual*/ bool value(Handle handle, const QString &subPath, QVariant *data);
    /*virtual*/ QSet<QString> children(Handle handle);

    /*virtual*/ QValueSpace::LayerOptions layerOptions() const;

    /* QValueSpaceSubscriber functions */
    /*virtual*/ bool supportsInterestNotification() const;
    /*virtual*/ bool notifyInterest(Handle handle, bool interested);

    /* QValueSpacePublisher functions */
    /*virtual*/ bool setValue(QValueSpacePublisher *creator, Handle handle,
                              const QString &subPath, const QVariant &value);
    /*virtual*/ bool removeValue(QValueSpacePublisher *creator, Handle handle,
                                 const QString &subPath);
    /*virtual*/ bool removeSubTree(QValueSpacePublisher *creator, Handle handle);
    /*virtual*/ void addWatch(QValueSpacePublisher *creator, Handle handle);
    /*virtual*/ void removeWatches(QValueSpacePublisher *creator, Handle parent);
    /*virtual*/ void sync();

public:
    static GConfLayer *instance();

private slots:
    void notifyChanged(const QString &key, const QVariant &value);

private:
    struct GConfHandle {
        GConfHandle(const QString &p)
        :   path(p), refCount(1)
        {
        }

        QString path;
        unsigned int refCount;
    };

    QHash<QString, GConfHandle *> m_handles;

    GConfHandle *gConfHandle(Handle handle)
    {
        if (handle == InvalidHandle)
            return 0;

        GConfHandle *h = reinterpret_cast<GConfHandle *>(handle);
        if (m_handles.values().contains(h))
            return h;

        return 0;
    }

    //private methods not locking a mutex
    bool getValue(Handle handle, const QString &subPath, QVariant *data);
    Handle getItem(Handle parent, const QString &subPath);
    void doRemoveHandle(Handle handle);

private:    //data
    QSet<GConfHandle *> m_monitoringHandles;
    QMap<QString, GConfItem *> m_monitoringItems;
    QMutex m_mutex;
};

QTM_END_NAMESPACE

#endif //GCONFLAYER_H