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

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the Qt Mobility Components.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

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

#ifndef GCONFITEM_H

#define GCONFITEM_H

#include <QVariant>

#include <QStringList>

#include <QObject>

/*!

  \brief GConfItem is a simple C++ wrapper for GConf.

  Creating a GConfItem instance gives you access to a single GConf

  key.  You can get and set its value, and connect to its

  valueChanged() signal to be notified about changes.

  The value of a GConf key is returned to you as a QVariant, and you

  pass in a QVariant when setting the value.  GConfItem converts

  between a QVariant and GConf values as needed, and according to the

  following rules:

  - A QVariant of type QVariant::Invalid denotes an unset GConf key.

  - QVariant::Int, QVariant::Double, QVariant::Bool are converted to

    and from the obvious equivalents.

  - QVariant::String is converted to/from a GConf string and always

    uses the UTF-8 encoding.  No other encoding is supported.

  - QVariant::StringList is converted to a list of UTF-8 strings.

  - QVariant::List (which denotes a QList<QVariant>) is converted

    to/from a GConf list.  All elements of such a list must have the

    same type, and that type must be one of QVariant::Int,

    QVariant::Double, QVariant::Bool, or QVariant::String.  (A list of

    strings is returned as a QVariant::StringList, however, when you

    get it back.)

  - Any other QVariant or GConf value is essentially ignored.

  \warning GConfItem is as thread-safe as GConf.

*/

class GConfItem : public QObject

{

    Q_OBJECT

 public:

    /*! Initializes a GConfItem to access the GConf key denoted by

        \a key.  Key names should follow the normal GConf conventions

        like "/myapp/settings/first".

        \param key    The name of the key.

        \param parent Parent object

    */

    explicit GConfItem(const QString &key, QObject *parent = 0);

    /*! Finalizes a GConfItem.

     */

    virtual ~GConfItem();

    /*! Returns the key of this item, as given to the constructor.

     */

    QString key() const;

    /*! Returns the current value of this item, as a QVariant.

     */

    QVariant value() const;

    /*! Returns the current value of this item, as a QVariant.  If

     *  there is no value for this item, return \a def instead.

     */

    QVariant value(const QVariant &def) const;

    /*! Set the value of this item to \a val.  If \a val can not be

        represented in GConf or GConf refuses to accept it for other

        reasons, the current value is not changed and nothing happens.

        When the new value is different from the old value, the

        changedValue() signal is emitted on this GConfItem as part

        of calling set(), but other GConfItem:s for the same key do

        only receive a notification once the main loop runs.

        \param val  The new value.

    */

    void set(const QVariant &val);

    /*! Unset this item.  This is equivalent to

        \code

        item.set(QVariant(QVariant::Invalid));

        \endcode

     */

    void unset();

    /*! Return a list of the directories below this item.  The

        returned strings are absolute key names like

        "/myapp/settings".

        A directory is a key that has children.  The same key might

        also have a value, but that is confusing and best avoided.

    */

    QList<QString> listDirs() const;

    /*! Return a list of entries below this item.  The returned

        strings are absolute key names like "/myapp/settings/first".

        A entry is a key that has a value.  The same key might also

        have children, but that is confusing and is best avoided.

    */

    QList<QString> listEntries() const;

 signals:

    /*! Emitted when the value of this item has changed.

     */

    void valueChanged();

 private:

    friend struct GConfItemPrivate;

    struct GConfItemPrivate *priv;

    void update_value(bool emit_signal);

};

#endif // GCONFITEM_H