/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
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**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** accordance with the commercial license agreement provided with the
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** following information to ensure the GNU Lesser General Public License
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****************************************************************************/

#include "qqmlabstractbinding_p.h"

#include <QtQml/qqmlinfo.h>
#include <private/qqmlbinding_p.h>
#include <private/qqmlvaluetypeproxybinding_p.h>

QT_BEGIN_NAMESPACE

QQmlAbstractBinding::QQmlAbstractBinding()
    : m_targetIndex(-1)
{
    Q_ASSERT(!isAddedToObject());
}

QQmlAbstractBinding::~QQmlAbstractBinding()
{
    Q_ASSERT(!ref);
    Q_ASSERT(!isAddedToObject());

    if (m_nextBinding.data() && !m_nextBinding->ref.deref())
        delete m_nextBinding.data();
}

/*!
Add this binding to \a object.

This transfers ownership of the binding to the object, marks the object's property as
being bound.

However, it does not enable the binding itself or call update() on it.
*/
void QQmlAbstractBinding::addToObject()
{
    Q_ASSERT(!nextBinding());
    Q_ASSERT(isAddedToObject() == false);

    QObject *obj = targetObject();
    Q_ASSERT(obj);

    QQmlData *data = QQmlData::get(obj, true);

    int coreIndex;
    if (QQmlPropertyData::decodeValueTypePropertyIndex(targetPropertyIndex(), &coreIndex) != -1) {
        // Value type

        // Find the value type proxy (if there is one)
        QQmlValueTypeProxyBinding *proxy = 0;
        if (data->hasBindingBit(coreIndex)) {
            QQmlAbstractBinding *b = data->bindings;
            while (b && b->targetPropertyIndex() != coreIndex)
                b = b->nextBinding();
            Q_ASSERT(b && b->isValueTypeProxy());
            proxy = static_cast<QQmlValueTypeProxyBinding *>(b);
        }

        if (!proxy) {
            proxy = new QQmlValueTypeProxyBinding(obj, coreIndex);

            Q_ASSERT(proxy->targetPropertyIndex() == coreIndex);
            Q_ASSERT(proxy->targetObject() == obj);

            proxy->addToObject();
        }

        setNextBinding(proxy->m_bindings.data());
        proxy->m_bindings = this;

    } else {
        setNextBinding(data->bindings);
        if (data->bindings) {
            data->bindings->ref.deref();
            Q_ASSERT(data->bindings->ref.refCount > 0);
        }
        data->bindings = this;
        ref.ref();

        data->setBindingBit(obj, coreIndex);
    }

    setAddedToObject(true);
}

/*!
Remove the binding from the object.
*/
void QQmlAbstractBinding::removeFromObject()
{
    if (!isAddedToObject())
        return;

    setAddedToObject(false);

    QObject *obj = targetObject();
    QQmlData *data = QQmlData::get(obj, false);
    Q_ASSERT(data);

    QQmlAbstractBinding::Ptr next;
    next = nextBinding();
    setNextBinding(0);

    int coreIndex;
    if (QQmlPropertyData::decodeValueTypePropertyIndex(targetPropertyIndex(), &coreIndex) != -1) {

        // Find the value type binding
        QQmlAbstractBinding *vtbinding = data->bindings;
        while (vtbinding->targetPropertyIndex() != coreIndex) {
            vtbinding = vtbinding->nextBinding();
            Q_ASSERT(vtbinding);
        }
        Q_ASSERT(vtbinding->isValueTypeProxy());

        QQmlValueTypeProxyBinding *vtproxybinding =
            static_cast<QQmlValueTypeProxyBinding *>(vtbinding);

        QQmlAbstractBinding *binding = vtproxybinding->m_bindings.data();
        if (binding == this) {
            vtproxybinding->m_bindings = next;
        } else {
           while (binding->nextBinding() != this) {
              binding = binding->nextBinding();
              Q_ASSERT(binding);
           }
           binding->setNextBinding(next.data());
        }

        // Value type - we don't remove the proxy from the object.  It will sit their happily
        // doing nothing until it is removed by a write, a binding change or it is reused
        // to hold more sub-bindings.
        return;
    }

    if (data->bindings == this) {
        if (next.data())
            next->ref.ref();
        data->bindings = next.data();
        if (!ref.deref())
            delete this;
    } else {
        QQmlAbstractBinding *binding = data->bindings;
        while (binding->nextBinding() != this) {
            binding = binding->nextBinding();
            Q_ASSERT(binding);
        }
        binding->setNextBinding(next.data());
    }

    data->clearBindingBit(coreIndex);
}

void QQmlAbstractBinding::printBindingLoopError(QQmlProperty &prop)
{
    qmlInfo(prop.object()) << QString(QLatin1String("Binding loop detected for property \"%1\"")).arg(prop.name());
}

QString QQmlAbstractBinding::expression() const
{
    return QLatin1String("<Unknown>");
}

bool QQmlAbstractBinding::isValueTypeProxy() const
{
    return false;
}

QT_END_NAMESPACE