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#include <qmlengine.h>
#include <qmlcontext.h>
#include <private/qobject_p.h>
#include <QtCore/qfile.h>
#include <QtCore/qdebug.h>
#include <QtScript/qscriptvalue.h>
#include <QtScript/qscriptcontext.h>
#include <QtScript/qscriptengine.h>
#include <private/qmlnullablevalue_p_p.h>
#include "qmlbind_p.h"

QT_BEGIN_NAMESPACE

class QmlBindPrivate : public QObjectPrivate
{
public:
    QmlBindPrivate() : when(true), componentComplete(false), obj(0) {}

    bool when : 1;
    bool componentComplete : 1;
    QObject *obj;
    QString prop;
    QmlNullableValue<QVariant> value;
};

QML_DEFINE_TYPE(Qt,4,6,Binding,QmlBind)
/*!
    \qmlclass Binding QmlBind
    \brief The Binding element allows arbitrary property bindings to be created.

    Sometimes it is necessary to bind to a property of an object that wasn't
    directly instantiated by QML - generally a property of a class exported
    to QML by C++. In these cases, regular property binding doesn't work. Binding
    allows you to bind any value to any property.

    For example, imagine a C++ application that maps an "app.enteredText"
    property into QML. You could use Binding to update the enteredText property
    like this.
    \code
    TextEdit { id: myTextField; text: "Please type here..." }
    Binding { target: app; property: "enteredText"; value: myTextField.text }
    \endcode
    Whenever the text in the TextEdit is updated, the C++ property will be
    updated also.

    If the binding target or binding property is changed, the bound value is
    immediately pushed onto the new target.
    */
/*!
    \internal
    \class QmlBind
    \ingroup group_utility
    \brief The QmlBind class allows arbitrary property bindings to be created.

    Simple bindings are usually earier to do in-place rather than creating a
    QmlBind item. For that reason, QmlBind is usually used to transfer property information
    from Qml to C++.

    \sa cppqml
    */
QmlBind::QmlBind(QObject *parent)
    : QObject(*(new QmlBindPrivate), parent)
{
}

QmlBind::~QmlBind()
{
}

bool QmlBind::when() const
{
    Q_D(const QmlBind);
    return d->when;
}

void QmlBind::setWhen(bool v)
{
    Q_D(QmlBind);
    d->when = v;
    eval();
}

/*!
    \qmlproperty Object Binding::target

    The object to be updated.
*/
QObject *QmlBind::object()
{
    Q_D(const QmlBind);
    return d->obj;
}

void QmlBind::setObject(QObject *obj)
{
    Q_D(QmlBind);
    d->obj = obj;
    eval();
}

/*!
    \qmlproperty string Binding::property

    The property to be updated.
*/
QString QmlBind::property() const
{
    Q_D(const QmlBind);
    return d->prop;
}

void QmlBind::setProperty(const QString &p)
{
    Q_D(QmlBind);
    d->prop = p;
    eval();
}

/*!
    \qmlproperty any Binding::value

    The value to be set on the target object and property.  This can be a
    constant (which isn't very useful), or a bound expression.
*/
QVariant QmlBind::value() const
{
    Q_D(const QmlBind);
    return d->value.value;
}

void QmlBind::setValue(const QVariant &v)
{
    Q_D(QmlBind);
    d->value.value = v;
    d->value.isNull = false;
    eval();
}

void QmlBind::componentComplete()
{
    Q_D(QmlBind);
    d->componentComplete = true;
    eval();
}

void QmlBind::eval()
{
    Q_D(QmlBind);
    if (!d->obj || d->value.isNull || !d->when || !d->componentComplete)
        return;

    QmlMetaProperty prop(d->obj, d->prop);
    prop.write(d->value.value);
}

QT_END_NAMESPACE