path: root/src/declarative/graphicsitems/qdeclarativevisualitemmodel.cpp

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#include "private/qdeclarativevisualitemmodel_p.h"

#include "qdeclarativeitem.h"

#include <qdeclarativecontext.h>
#include <qdeclarativeengine.h>
#include <qdeclarativeexpression.h>
#include <qdeclarativepackage_p.h>
#include <qdeclarativeopenmetaobject_p.h>
#include <qdeclarativelistaccessor_p.h>
#include <qdeclarativeinfo.h>
#include <qdeclarativedeclarativedata_p.h>
#include <qdeclarativepropertycache_p.h>
#include <qdeclarativeguard_p.h>
#include <qdeclarativeglobal_p.h>

#include <qlistmodelinterface_p.h>
#include <qhash.h>
#include <qlist.h>
#include <qmetaobjectbuilder_p.h>
#include <QtCore/qdebug.h>

#include <private/qobject_p.h>

QT_BEGIN_NAMESPACE

QHash<QObject*, QDeclarativeVisualItemModelAttached*> QDeclarativeVisualItemModelAttached::attachedProperties;


class QDeclarativeVisualItemModelPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QDeclarativeVisualItemModel)
public:
    QDeclarativeVisualItemModelPrivate() : QObjectPrivate() {}

    static void children_append(QDeclarativeListProperty<QDeclarativeItem> *prop, QDeclarativeItem *item) {
        item->QObject::setParent(prop->object);
        static_cast<QDeclarativeVisualItemModelPrivate *>(prop->data)->children.append(item);
        static_cast<QDeclarativeVisualItemModelPrivate *>(prop->data)->itemAppended();
        static_cast<QDeclarativeVisualItemModelPrivate *>(prop->data)->emitChildrenChanged();
    }

    static int children_count(QDeclarativeListProperty<QDeclarativeItem> *prop) {
        return static_cast<QDeclarativeVisualItemModelPrivate *>(prop->data)->children.count();
    }

    static QDeclarativeItem *children_at(QDeclarativeListProperty<QDeclarativeItem> *prop, int index) {
        return static_cast<QDeclarativeVisualItemModelPrivate *>(prop->data)->children.at(index);
    }

    void itemAppended() {
        Q_Q(QDeclarativeVisualItemModel);
        QDeclarativeVisualItemModelAttached *attached = QDeclarativeVisualItemModelAttached::properties(children.last());
        attached->setIndex(children.count()-1);
        emit q->itemsInserted(children.count()-1, 1);
        emit q->countChanged();
    }

    void emitChildrenChanged() {
        Q_Q(QDeclarativeVisualItemModel);
        emit q->childrenChanged();
    }

    QList<QDeclarativeItem *> children;
};


/*!
    \qmlclass VisualItemModel QDeclarativeVisualItemModel
  \since 4.7
    \brief The VisualItemModel allows items to be provided to a view.

    The children of the VisualItemModel are provided in a model which
    can be used in a view.  Note that no delegate should be
    provided to a view since the VisualItemModel contains the
    visual delegate (items).

    An item can determine its index within the
    model via the VisualItemModel.index attached property.

    The example below places three colored rectangles in a ListView.
    \code
    Item {
        VisualItemModel {
            id: itemModel
            Rectangle { height: 30; width: 80; color: "red" }
            Rectangle { height: 30; width: 80; color: "green" }
            Rectangle { height: 30; width: 80; color: "blue" }
        }

        ListView {
            anchors.fill: parent
            model: itemModel
        }
    }
    \endcode
*/
QDeclarativeVisualItemModel::QDeclarativeVisualItemModel()
    : QDeclarativeVisualModel(*(new QDeclarativeVisualItemModelPrivate))
{
}

QDeclarativeListProperty<QDeclarativeItem> QDeclarativeVisualItemModel::children()
{
    Q_D(QDeclarativeVisualItemModel);
    return QDeclarativeListProperty<QDeclarativeItem>(this, d, d->children_append,
                                                      d->children_count, d->children_at);
}

/*!
    \qmlproperty int VisualItemModel::count

    The number of items in the model.  This property is readonly.
*/
int QDeclarativeVisualItemModel::count() const
{
    Q_D(const QDeclarativeVisualItemModel);
    return d->children.count();
}

bool QDeclarativeVisualItemModel::isValid() const
{
    return true;
}

QDeclarativeItem *QDeclarativeVisualItemModel::item(int index, bool)
{
    Q_D(QDeclarativeVisualItemModel);
    return d->children.at(index);
}

QDeclarativeVisualModel::ReleaseFlags QDeclarativeVisualItemModel::release(QDeclarativeItem *)
{
    // Nothing to do
    return 0;
}

void QDeclarativeVisualItemModel::completeItem()
{
    // Nothing to do
}

QString QDeclarativeVisualItemModel::stringValue(int index, const QString &name)
{
    Q_D(QDeclarativeVisualItemModel);
    if (index < 0 || index >= d->children.count())
        return QString();
    return QDeclarativeEngine::contextForObject(d->children.at(index))->contextProperty(name).toString();
}

QVariant QDeclarativeVisualItemModel::evaluate(int index, const QString &expression, QObject *objectContext)
{
    Q_D(QDeclarativeVisualItemModel);
    if (index < 0 || index >= d->children.count())
        return QVariant();
    QDeclarativeContext *ccontext = qmlContext(this);
    QDeclarativeContext *ctxt = new QDeclarativeContext(ccontext);
    ctxt->setContextObject(d->children.at(index));
    QDeclarativeExpression e(ctxt, expression, objectContext);
    QVariant value = e.value();
    delete ctxt;
    return value;
}

int QDeclarativeVisualItemModel::indexOf(QDeclarativeItem *item, QObject *) const
{
    Q_D(const QDeclarativeVisualItemModel);
    return d->children.indexOf(item);
}

QDeclarativeVisualItemModelAttached *QDeclarativeVisualItemModel::qmlAttachedProperties(QObject *obj)
{
    return QDeclarativeVisualItemModelAttached::properties(obj);
}

//============================================================================

class VDMDelegateDataType : public QDeclarativeOpenMetaObjectType
{
public:
    VDMDelegateDataType(const QMetaObject *base, QDeclarativeEngine *engine) : QDeclarativeOpenMetaObjectType(base, engine) {}

    void propertyCreated(int, QMetaPropertyBuilder &prop) {
        prop.setWritable(false);
    }
};

class QDeclarativeVisualDataModelParts;
class QDeclarativeVisualDataModelData;
class QDeclarativeVisualDataModelPrivate : public QObjectPrivate
{
public:
    QDeclarativeVisualDataModelPrivate(QDeclarativeContext *);

    static QDeclarativeVisualDataModelPrivate *get(QDeclarativeVisualDataModel *m) {
        return static_cast<QDeclarativeVisualDataModelPrivate *>(QObjectPrivate::get(m));
    }

    QDeclarativeGuard<QListModelInterface> m_listModelInterface;
    QDeclarativeGuard<QAbstractItemModel> m_abstractItemModel;
    QDeclarativeGuard<QDeclarativeVisualDataModel> m_visualItemModel;
    QString m_part;

    QDeclarativeComponent *m_delegate;
    QDeclarativeContext *m_context;
    QList<int> m_roles;
    QHash<QByteArray,int> m_roleNames;
    void ensureRoles() {
        if (m_roleNames.isEmpty()) {
            if (m_listModelInterface) {
                m_roles = m_listModelInterface->roles();
                for (int ii = 0; ii < m_roles.count(); ++ii)
                    m_roleNames.insert(m_listModelInterface->toString(m_roles.at(ii)).toUtf8(), m_roles.at(ii));
                if (m_roles.count() == 1)
                    m_roleNames.insert("modelData", m_roles.at(0));
            } else if (m_abstractItemModel) {
                for (QHash<int,QByteArray>::const_iterator it = m_abstractItemModel->roleNames().begin();
                        it != m_abstractItemModel->roleNames().end(); ++it) {
                    m_roles.append(it.key());
                    m_roleNames.insert(*it, it.key());
                }
                if (m_roles.count() == 1)
                    m_roleNames.insert("modelData", m_roles.at(0));
            } else if (m_listAccessor) {
                m_roleNames.insert("modelData", 0);
                if (m_listAccessor->type() == QDeclarativeListAccessor::Instance) {
                    if (QObject *object = m_listAccessor->at(0).value<QObject*>()) {
                        int count = object->metaObject()->propertyCount();
                        for (int ii = 1; ii < count; ++ii) {
                            const QMetaProperty &prop = object->metaObject()->property(ii);
                            m_roleNames.insert(prop.name(), 0);
                        }
                    }
                }
            }
        }
    }

    void createMetaData() {
        if (!m_metaDataCreated) {
            ensureRoles();
            QHash<QByteArray, int>::const_iterator it = m_roleNames.begin();
            while (it != m_roleNames.end()) {
                m_delegateDataType->createProperty(it.key());
                ++it;
            }
            m_metaDataCreated = true;
        }
    }

    struct ObjectRef {
        ObjectRef(QObject *object=0) : obj(object), ref(1) {}
        QObject *obj;
        int ref;
    };
    class Cache : public QHash<int, ObjectRef> {
    public:
        QObject *getItem(int index) {
            QObject *item = 0;
            QHash<int,ObjectRef>::iterator it = find(index);
            if (it != end()) {
                (*it).ref++;
                item = (*it).obj;
            }
            return item;
        }
        QObject *item(int index) {
            QObject *item = 0;
            QHash<int, ObjectRef>::const_iterator it = find(index);
            if (it != end())
                item = (*it).obj;
            return item;
        }
        void insertItem(int index, QObject *obj) {
            insert(index, ObjectRef(obj));
        }
        bool releaseItem(QObject *obj) {
            QHash<int, ObjectRef>::iterator it = begin();
            for (; it != end(); ++it) {
                ObjectRef &objRef = *it;
                if (objRef.obj == obj) {
                    if (--objRef.ref == 0) {
                        erase(it);
                        return true;
                    }
                    break;
                }
            }
            return false;
        }
    };

    int modelCount() const {
        if (m_visualItemModel)
            return m_visualItemModel->count();
        if (m_listModelInterface)
            return m_listModelInterface->count();
        if (m_abstractItemModel)
            return m_abstractItemModel->rowCount(m_root);
        if (m_listAccessor)
            return m_listAccessor->count();
        return 0;
    }

    Cache m_cache;
    QHash<QObject *, QDeclarativePackage*> m_packaged;

    QDeclarativeVisualDataModelParts *m_parts;
    friend class QDeclarativeVisualItemParts;

    VDMDelegateDataType *m_delegateDataType;
    friend class QDeclarativeVisualDataModelData;
    bool m_metaDataCreated;
    bool m_metaDataCacheable;

    QDeclarativeVisualDataModelData *data(QObject *item);

    QVariant m_modelVariant;
    QDeclarativeListAccessor *m_listAccessor;

    QModelIndex m_root;
};

class QDeclarativeVisualDataModelDataMetaObject : public QDeclarativeOpenMetaObject
{
public:
    QDeclarativeVisualDataModelDataMetaObject(QObject *parent, QDeclarativeOpenMetaObjectType *type)
    : QDeclarativeOpenMetaObject(parent, type) {}

    virtual QVariant initialValue(int);
    virtual int createProperty(const char *, const char *);

private:
    friend class QDeclarativeVisualDataModelData;
    QHash<int,int> roleToProp;
};

class QDeclarativeVisualDataModelData : public QObject
{
Q_OBJECT
public:
    QDeclarativeVisualDataModelData(int index, QDeclarativeVisualDataModel *model);
    ~QDeclarativeVisualDataModelData();

    Q_PROPERTY(int index READ index NOTIFY indexChanged)
    int index() const;
    void setIndex(int index);

    int propForRole(int) const;
    void setValue(int, const QVariant &);

Q_SIGNALS:
    void indexChanged();

private:
    friend class QDeclarativeVisualDataModelDataMetaObject;
    int m_index;
    QDeclarativeGuard<QDeclarativeVisualDataModel> m_model;
    QDeclarativeVisualDataModelDataMetaObject *m_meta;
};

int QDeclarativeVisualDataModelData::propForRole(int id) const
{
    QHash<int,int>::const_iterator it = m_meta->roleToProp.find(id);
    if (it != m_meta->roleToProp.end())
        return m_meta->roleToProp[id];
    return -1;
}

void QDeclarativeVisualDataModelData::setValue(int id, const QVariant &val)
{
    m_meta->setValue(id, val);
}

int QDeclarativeVisualDataModelDataMetaObject::createProperty(const char *name, const char *type)
{
    QDeclarativeVisualDataModelData *data =
        static_cast<QDeclarativeVisualDataModelData *>(object());

    if (!data->m_model)
        return -1;

    QDeclarativeVisualDataModelPrivate *model = QDeclarativeVisualDataModelPrivate::get(data->m_model);
    if (data->m_index < 0 || data->m_index >= model->modelCount())
        return -1;

    if ((!model->m_listModelInterface || !model->m_abstractItemModel) && model->m_listAccessor) {
        if (model->m_listAccessor->type() == QDeclarativeListAccessor::ListProperty) {
            model->ensureRoles();
            QObject *object = model->m_listAccessor->at(data->m_index).value<QObject*>();
            if (object && (object->property(name).isValid() || qstrcmp(name,"modelData")==0))
                return QDeclarativeOpenMetaObject::createProperty(name, type);
        }
    }
    return -1;
}

QVariant QDeclarativeVisualDataModelDataMetaObject::initialValue(int propId)
{
    QDeclarativeVisualDataModelData *data =
        static_cast<QDeclarativeVisualDataModelData *>(object());

    Q_ASSERT(data->m_model);
    QDeclarativeVisualDataModelPrivate *model = QDeclarativeVisualDataModelPrivate::get(data->m_model);

    QByteArray propName = name(propId);
    if ((!model->m_listModelInterface || !model->m_abstractItemModel) && model->m_listAccessor) {
        if (propName == "modelData") {
            if (model->m_listAccessor->type() == QDeclarativeListAccessor::Instance) {
                QObject *object = model->m_listAccessor->at(0).value<QObject*>();
                return object->metaObject()->property(1).read(object); // the first property after objectName
            }
            return model->m_listAccessor->at(data->m_index);
        } else {
            // return any property of a single object instance.
            QObject *object = model->m_listAccessor->at(data->m_index).value<QObject*>();
            return object->property(propName);
        }
    } else if (model->m_listModelInterface) {
        model->ensureRoles();
        QHash<QByteArray,int>::const_iterator it = model->m_roleNames.find(propName);
        if (it != model->m_roleNames.end()) {
            roleToProp.insert(*it, propId);
            QVariant value = model->m_listModelInterface->data(data->m_index, *it);
            return value;
        } else if (model->m_roles.count() == 1 && propName == "modelData") {
            //for compatability with other lists, assign modelData if there is only a single role
            roleToProp.insert(model->m_roles.first(), propId);
            QVariant value = model->m_listModelInterface->data(data->m_index, model->m_roles.first());
            return value;
        }
    } else if (model->m_abstractItemModel) {
        model->ensureRoles();
        QHash<QByteArray,int>::const_iterator it = model->m_roleNames.find(propName);
        if (it != model->m_roleNames.end()) {
            roleToProp.insert(*it, propId);
            QModelIndex index = model->m_abstractItemModel->index(data->m_index, 0, model->m_root);
            return model->m_abstractItemModel->data(index, *it);
        }
    }
    Q_ASSERT(!"Can never be reached");
    return QVariant();
}

QDeclarativeVisualDataModelData::QDeclarativeVisualDataModelData(int index,
                                               QDeclarativeVisualDataModel *model)
: m_index(index), m_model(model),
m_meta(new QDeclarativeVisualDataModelDataMetaObject(this, QDeclarativeVisualDataModelPrivate::get(model)->m_delegateDataType))
{
    QDeclarativeVisualDataModelPrivate *modelPriv = QDeclarativeVisualDataModelPrivate::get(model);
    if (modelPriv->m_metaDataCacheable) {
        if (!modelPriv->m_metaDataCreated)
            modelPriv->createMetaData();
        m_meta->setCached(true);
    }
}

QDeclarativeVisualDataModelData::~QDeclarativeVisualDataModelData()
{
}

int QDeclarativeVisualDataModelData::index() const
{
    return m_index;
}

// This is internal only - it should not be set from qml
void QDeclarativeVisualDataModelData::setIndex(int index)
{
    m_index = index;
    emit indexChanged();
}

//---------------------------------------------------------------------------

class QDeclarativeVisualDataModelPartsMetaObject : public QDeclarativeOpenMetaObject
{
public:
    QDeclarativeVisualDataModelPartsMetaObject(QObject *parent)
    : QDeclarativeOpenMetaObject(parent) {}

    virtual void propertyCreated(int, QMetaPropertyBuilder &);
    virtual QVariant initialValue(int);
};

class QDeclarativeVisualDataModelParts : public QObject
{
Q_OBJECT
public:
    QDeclarativeVisualDataModelParts(QDeclarativeVisualDataModel *parent);

private:
    friend class QDeclarativeVisualDataModelPartsMetaObject;
    QDeclarativeVisualDataModel *model;
};

void QDeclarativeVisualDataModelPartsMetaObject::propertyCreated(int, QMetaPropertyBuilder &prop)
{
    prop.setWritable(false);
}

QVariant QDeclarativeVisualDataModelPartsMetaObject::initialValue(int id)
{
    QDeclarativeVisualDataModel *m = new QDeclarativeVisualDataModel;
    m->setParent(object());
    m->setPart(QString::fromUtf8(name(id)));
    m->setModel(QVariant::fromValue(static_cast<QDeclarativeVisualDataModelParts *>(object())->model));

    QVariant var = QVariant::fromValue((QObject *)m);
    return var;
}

QDeclarativeVisualDataModelParts::QDeclarativeVisualDataModelParts(QDeclarativeVisualDataModel *parent)
: QObject(parent), model(parent)
{
    new QDeclarativeVisualDataModelPartsMetaObject(this);
}

QDeclarativeVisualDataModelPrivate::QDeclarativeVisualDataModelPrivate(QDeclarativeContext *ctxt)
: m_listModelInterface(0), m_abstractItemModel(0), m_visualItemModel(0), m_delegate(0)
, m_context(ctxt), m_parts(0), m_delegateDataType(0), m_metaDataCreated(false)
, m_metaDataCacheable(false), m_listAccessor(0)
{
}

QDeclarativeVisualDataModelData *QDeclarativeVisualDataModelPrivate::data(QObject *item)
{
    QDeclarativeVisualDataModelData *dataItem =
        item->findChild<QDeclarativeVisualDataModelData *>();
    Q_ASSERT(dataItem);
    return dataItem;
}

//---------------------------------------------------------------------------

/*!
    \qmlclass VisualDataModel QDeclarativeVisualDataModel
    \brief The VisualDataModel encapsulates a model and delegate

    A VisualDataModel encapsulates a model and the delegate that will
    be instantiated for items in the model.

    It is usually not necessary to create a VisualDataModel directly,
    since the QML views will create one internally.

    The example below illustrates using a VisualDataModel with a ListView.

    \code
    VisualDataModel {
        id: visualModel
        model: myModel
        delegate: Component {
            Rectangle {
                height: 25
                width: 100
                Text { text: "Name:" + name}
            }
        }
    }
    ListView {
        width: 100
        height: 100
        anchors.fill: parent
        model: visualModel
    }
    \endcode
*/

QDeclarativeVisualDataModel::QDeclarativeVisualDataModel()
: QDeclarativeVisualModel(*(new QDeclarativeVisualDataModelPrivate(0)))
{
}

QDeclarativeVisualDataModel::QDeclarativeVisualDataModel(QDeclarativeContext *ctxt)
: QDeclarativeVisualModel(*(new QDeclarativeVisualDataModelPrivate(ctxt)))
{
}

QDeclarativeVisualDataModel::~QDeclarativeVisualDataModel()
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_listAccessor)
        delete d->m_listAccessor;
    if (d->m_delegateDataType)
        d->m_delegateDataType->release();
}

/*!
    \qmlproperty model VisualDataModel::model
    This property holds the model providing data for the VisualDataModel.

    The model provides a set of data that is used to create the items
    for a view.  For large or dynamic datasets the model is usually
    provided by a C++ model object.  The C++ model object must be a \l
    {QAbstractItemModel} subclass or a simple list.

    Models can also be created directly in QML, using a \l{ListModel} or
    \l{XmlListModel}.

    \sa {qmlmodels}{Data Models}
*/
QVariant QDeclarativeVisualDataModel::model() const
{
    Q_D(const QDeclarativeVisualDataModel);
    return d->m_modelVariant;
}

void QDeclarativeVisualDataModel::setModel(const QVariant &model)
{
    Q_D(QDeclarativeVisualDataModel);
    delete d->m_listAccessor;
    d->m_listAccessor = 0;
    d->m_modelVariant = model;
    if (d->m_listModelInterface) {
        // Assume caller has released all items.
        QObject::disconnect(d->m_listModelInterface, SIGNAL(itemsChanged(int,int,QList<int>)),
                this, SLOT(_q_itemsChanged(int,int,QList<int>)));
        QObject::disconnect(d->m_listModelInterface, SIGNAL(itemsInserted(int,int)),
                this, SLOT(_q_itemsInserted(int,int)));
        QObject::disconnect(d->m_listModelInterface, SIGNAL(itemsRemoved(int,int)),
                this, SLOT(_q_itemsRemoved(int,int)));
        QObject::disconnect(d->m_listModelInterface, SIGNAL(itemsMoved(int,int,int)),
                this, SLOT(_q_itemsMoved(int,int,int)));
        d->m_listModelInterface = 0;
    } else if (d->m_abstractItemModel) {
        QObject::disconnect(d->m_abstractItemModel, SIGNAL(rowsInserted(const QModelIndex &,int,int)),
                            this, SLOT(_q_rowsInserted(const QModelIndex &,int,int)));
        QObject::disconnect(d->m_abstractItemModel, SIGNAL(rowsRemoved(const QModelIndex &,int,int)),
                            this, SLOT(_q_rowsRemoved(const QModelIndex &,int,int)));
        QObject::disconnect(d->m_abstractItemModel, SIGNAL(dataChanged(const QModelIndex&,const QModelIndex&)),
                            this, SLOT(_q_dataChanged(const QModelIndex&,const QModelIndex&)));
        QObject::disconnect(d->m_abstractItemModel, SIGNAL(rowsMoved(const QModelIndex&,int,int,const QModelIndex&,int)),
                            this, SLOT(_q_rowsMoved(const QModelIndex&,int,int,const QModelIndex&,int)));
        QObject::disconnect(d->m_abstractItemModel, SIGNAL(modelReset()), this, SLOT(_q_modelReset()));
    } else if (d->m_visualItemModel) {
        QObject::disconnect(d->m_visualItemModel, SIGNAL(itemsInserted(int,int)),
                         this, SIGNAL(itemsInserted(int,int)));
        QObject::disconnect(d->m_visualItemModel, SIGNAL(itemsRemoved(int,int)),
                         this, SIGNAL(itemsRemoved(int,int)));
        QObject::disconnect(d->m_visualItemModel, SIGNAL(itemsMoved(int,int,int)),
                         this, SIGNAL(itemsMoved(int,int,int)));
        QObject::disconnect(d->m_visualItemModel, SIGNAL(createdPackage(int,QDeclarativePackage*)),
                         this, SLOT(_q_createdPackage(int,QDeclarativePackage*)));
        QObject::disconnect(d->m_visualItemModel, SIGNAL(destroyingPackage(QDeclarativePackage*)),
                         this, SLOT(_q_destroyingPackage(QDeclarativePackage*)));
        d->m_visualItemModel = 0;
    }

    d->m_roles.clear();
    d->m_roleNames.clear();
    if (d->m_delegateDataType)
        d->m_delegateDataType->release();
    d->m_metaDataCreated = 0;
    d->m_metaDataCacheable = false;
    d->m_delegateDataType = new VDMDelegateDataType(&QDeclarativeVisualDataModelData::staticMetaObject, d->m_context?d->m_context->engine():qmlEngine(this));

    QObject *object = qvariant_cast<QObject *>(model);
    if (object && (d->m_listModelInterface = qobject_cast<QListModelInterface *>(object))) {
        QObject::connect(d->m_listModelInterface, SIGNAL(itemsChanged(int,int,QList<int>)),
                         this, SLOT(_q_itemsChanged(int,int,QList<int>)));
        QObject::connect(d->m_listModelInterface, SIGNAL(itemsInserted(int,int)),
                         this, SLOT(_q_itemsInserted(int,int)));
        QObject::connect(d->m_listModelInterface, SIGNAL(itemsRemoved(int,int)),
                         this, SLOT(_q_itemsRemoved(int,int)));
        QObject::connect(d->m_listModelInterface, SIGNAL(itemsMoved(int,int,int)),
                         this, SLOT(_q_itemsMoved(int,int,int)));
        d->m_metaDataCacheable = true;
        if (d->m_delegate && d->m_listModelInterface->count())
            emit itemsInserted(0, d->m_listModelInterface->count());
        return;
    } else if (object && (d->m_abstractItemModel = qobject_cast<QAbstractItemModel *>(object))) {
        QObject::connect(d->m_abstractItemModel, SIGNAL(rowsInserted(const QModelIndex &,int,int)),
                            this, SLOT(_q_rowsInserted(const QModelIndex &,int,int)));
        QObject::connect(d->m_abstractItemModel, SIGNAL(rowsRemoved(const QModelIndex &,int,int)),
                            this, SLOT(_q_rowsRemoved(const QModelIndex &,int,int)));
        QObject::connect(d->m_abstractItemModel, SIGNAL(dataChanged(const QModelIndex&,const QModelIndex&)),
                            this, SLOT(_q_dataChanged(const QModelIndex&,const QModelIndex&)));
        QObject::connect(d->m_abstractItemModel, SIGNAL(rowsMoved(const QModelIndex&,int,int,const QModelIndex&,int)),
                            this, SLOT(_q_rowsMoved(const QModelIndex&,int,int,const QModelIndex&,int)));
        QObject::connect(d->m_abstractItemModel, SIGNAL(modelReset()), this, SLOT(_q_modelReset()));
        d->m_metaDataCacheable = true;
        return;
    }
    if ((d->m_visualItemModel = qvariant_cast<QDeclarativeVisualDataModel *>(model))) {
        QObject::connect(d->m_visualItemModel, SIGNAL(itemsInserted(int,int)),
                         this, SIGNAL(itemsInserted(int,int)));
        QObject::connect(d->m_visualItemModel, SIGNAL(itemsRemoved(int,int)),
                         this, SIGNAL(itemsRemoved(int,int)));
        QObject::connect(d->m_visualItemModel, SIGNAL(itemsMoved(int,int,int)),
                         this, SIGNAL(itemsMoved(int,int,int)));
        QObject::connect(d->m_visualItemModel, SIGNAL(createdPackage(int,QDeclarativePackage*)),
                         this, SLOT(_q_createdPackage(int,QDeclarativePackage*)));
        QObject::connect(d->m_visualItemModel, SIGNAL(destroyingPackage(QDeclarativePackage*)),
                         this, SLOT(_q_destroyingPackage(QDeclarativePackage*)));
        return;
    }
    d->m_listAccessor = new QDeclarativeListAccessor;
    d->m_listAccessor->setList(model, d->m_context?d->m_context->engine():qmlEngine(this));
    if (d->m_listAccessor->type() != QDeclarativeListAccessor::ListProperty)
        d->m_metaDataCacheable = true;
    if (d->m_delegate && d->modelCount()) {
        emit itemsInserted(0, d->modelCount());
        emit countChanged();
    }
}

/*!
    \qmlproperty component VisualDataModel::delegate

    The delegate provides a template defining each item instantiated by a view.
    The index is exposed as an accessible \c index property.  Properties of the
    model are also available depending upon the type of \l {qmlmodels}{Data Model}.

    Here is an example delegate:
    \snippet doc/src/snippets/declarative/listview/listview.qml 0
*/
QDeclarativeComponent *QDeclarativeVisualDataModel::delegate() const
{
    Q_D(const QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->delegate();
    return d->m_delegate;
}

void QDeclarativeVisualDataModel::setDelegate(QDeclarativeComponent *delegate)
{
    Q_D(QDeclarativeVisualDataModel);
    bool wasValid = d->m_delegate != 0;
    d->m_delegate = delegate;
    if (!wasValid && d->modelCount() && d->m_delegate) {
        emit itemsInserted(0, d->modelCount());
        emit countChanged();
    }
    if (wasValid && !d->m_delegate && d->modelCount()) {
        emit itemsRemoved(0, d->modelCount());
        emit countChanged();
    }
}

/*!
    \qmlproperty QModelIndex VisualDataModel::rootIndex

    QAbstractItemModel provides a heirachical tree of data, whereas
    QML only operates on list data. rootIndex allows the children of
    any node in a QAbstractItemModel to be provided by this model.

    This property only affects models of type QAbstractItemModel.

    \code
    // main.cpp
    Q_DECLARE_METATYPE(QModelIndex)

    class MyModel : public QDirModel
    {
        Q_OBJECT
    public:
        MyModel(QDeclarativeContext *ctxt) : QDirModel(), context(ctxt) {
            QHash<int,QByteArray> roles = roleNames();
            roles.insert(FilePathRole, "path");
            setRoleNames(roles);
            context->setContextProperty("myModel", this);
            context->setContextProperty("myRoot", QVariant::fromValue(index(0,0,QModelIndex())));
        }

        Q_INVOKABLE void setRoot(const QString &path) {
            QModelIndex root = index(path);
            context->setContextProperty("myRoot", QVariant::fromValue(root));
        }

        QDeclarativeContext *context;
    };

    int main(int argc, char ** argv)
    {
        QApplication app(argc, argv);

        QDeclarativeView view;

        MyModel model(view.rootContext());

        view.setSource(QUrl("qrc:view.qml"));
        view.show();

        return app.exec();
    }

    #include "main.moc"
    \endcode

    \code
    // view.qml
    import Qt 4.6

    ListView {
        width: 200
        height: 200
        model: VisualDataModel {
            model: myModel
            rootIndex: myRoot
            delegate: Component {
                Rectangle {
                    height: 25; width: 100
                    Text { text: path }
                    MouseArea {
                        anchors.fill: parent;
                        onClicked: myModel.setRoot(path)
                    }
                }
            }
        }
    }
    \endcode

*/
QModelIndex QDeclarativeVisualDataModel::rootIndex() const
{
    Q_D(const QDeclarativeVisualDataModel);
    return d->m_root;
}

void QDeclarativeVisualDataModel::setRootIndex(const QModelIndex &root)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_root != root) {
        int oldCount = d->modelCount();
        d->m_root = root;
        int newCount = d->modelCount();
        if (d->m_delegate && oldCount)
            emit itemsRemoved(0, oldCount);
        if (d->m_delegate && newCount)
            emit itemsInserted(0, newCount);
        if (newCount != oldCount)
            emit countChanged();
        emit rootIndexChanged();
    }
}

QString QDeclarativeVisualDataModel::part() const
{
    Q_D(const QDeclarativeVisualDataModel);
    return d->m_part;
}

void QDeclarativeVisualDataModel::setPart(const QString &part)
{
    Q_D(QDeclarativeVisualDataModel);
    d->m_part = part;
}

int QDeclarativeVisualDataModel::count() const
{
    Q_D(const QDeclarativeVisualDataModel);
    return d->modelCount();
}

QDeclarativeItem *QDeclarativeVisualDataModel::item(int index, bool complete)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->item(index, d->m_part.toUtf8(), complete);
    return item(index, QByteArray(), complete);
}

/*
  Returns ReleaseStatus flags.
*/
QDeclarativeVisualDataModel::ReleaseFlags QDeclarativeVisualDataModel::release(QDeclarativeItem *item)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->release(item);

    ReleaseFlags stat = 0;
    QObject *obj = item;
    bool inPackage = false;

    QHash<QObject*,QDeclarativePackage*>::iterator it = d->m_packaged.find(item);
    if (it != d->m_packaged.end()) {
        QDeclarativePackage *package = *it;
        d->m_packaged.erase(it);
        if (d->m_packaged.contains(item))
            stat |= Referenced;
        inPackage = true;
        obj = package; // fall through and delete
    }

    if (d->m_cache.releaseItem(obj)) {
        if (inPackage) {
            emit destroyingPackage(qobject_cast<QDeclarativePackage*>(obj));
        } else {
            if (item->hasFocus())
                item->clearFocus();
            item->setOpacity(0.0);
            static_cast<QGraphicsItem*>(item)->setParentItem(0);
        }
        stat |= Destroyed;
        obj->deleteLater();
    } else if (!inPackage) {
        stat |= Referenced;
    }

    return stat;
}

/*!
    \qmlproperty object VisualDataModel::parts

    The \a parts property selects a VisualDataModel which creates
    delegates from the part named.  This is used in conjunction with
    the Package element.

    For example, the code below selects a model which creates
    delegates named \e list from a Package:

    \code
    VisualDataModel {
        id: visualModel
        delegate: Package {
            Item { Package.name: "list" }
        }
        model: myModel
    }

    ListView {
        width: 200; height:200
        model: visualModel.parts.list
    }
    \endcode

    \sa Package
*/
QObject *QDeclarativeVisualDataModel::parts()
{
    Q_D(QDeclarativeVisualDataModel);
    if (!d->m_parts)
        d->m_parts = new QDeclarativeVisualDataModelParts(this);
    return d->m_parts;
}

QDeclarativeItem *QDeclarativeVisualDataModel::item(int index, const QByteArray &viewId, bool complete)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->item(index, viewId, complete);

    if (d->modelCount() <= 0 || !d->m_delegate)
        return 0;
    QObject *nobj = d->m_cache.getItem(index);
    if (!nobj) {
        QDeclarativeContext *ccontext = d->m_context;
        if (!ccontext) ccontext = qmlContext(this);
        QDeclarativeContext *ctxt = new QDeclarativeContext(ccontext);
        QDeclarativeVisualDataModelData *data = new QDeclarativeVisualDataModelData(index, this);
        ctxt->setContextProperty(QLatin1String("model"), data);
        ctxt->setContextObject(data);
        nobj = d->m_delegate->beginCreate(ctxt);
        if (complete)
            d->m_delegate->completeCreate();
        if (nobj) {
            QDeclarative_setParent_noEvent(ctxt, nobj);
            QDeclarative_setParent_noEvent(data, nobj);
            d->m_cache.insertItem(index, nobj);
            if (QDeclarativePackage *package = qobject_cast<QDeclarativePackage *>(nobj))
                emit createdPackage(index, package);
        } else {
            delete data;
            delete ctxt;
            qWarning() << d->m_delegate->errors();
        }
    }
    QDeclarativeItem *item = qobject_cast<QDeclarativeItem *>(nobj);
    if (!item) {
        QDeclarativePackage *package = qobject_cast<QDeclarativePackage *>(nobj);
        if (package) {
            QObject *o = package->part(QString::fromUtf8(viewId));
            item = qobject_cast<QDeclarativeItem *>(o);
            if (item)
                d->m_packaged.insertMulti(item, package);
        }
    }
    if (!item) {
        d->m_cache.releaseItem(nobj);
        qmlInfo(d->m_delegate) << QDeclarativeVisualDataModel::tr("Delegate component must be Item type.");
    }

    return item;
}

void QDeclarativeVisualDataModel::completeItem()
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel) {
        d->m_visualItemModel->completeItem();
        return;
    }

    d->m_delegate->completeCreate();
}

QString QDeclarativeVisualDataModel::stringValue(int index, const QString &name)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->stringValue(index, name);

    if ((!d->m_listModelInterface && !d->m_abstractItemModel) || !d->m_delegate)
        return QString();

    QString val;
    QObject *data = 0;
    bool tempData = false;

    if (QObject *nobj = d->m_cache.item(index))
        data = d->data(nobj);
    if (!data) {
        data = new QDeclarativeVisualDataModelData(index, this);
        tempData = true;
    }

    QDeclarativeDeclarativeData *ddata = QDeclarativeDeclarativeData::get(data);
    if (ddata && ddata->propertyCache) {
        QDeclarativePropertyCache::Data *prop = ddata->propertyCache->property(name);
        if (prop) {
            if (prop->propType == QVariant::String) {
                void *args[] = { &val, 0 };
                QMetaObject::metacall(data, QMetaObject::ReadProperty, prop->coreIndex, args);
            } else if (prop->propType == qMetaTypeId<QVariant>()) {
                QVariant v;
                void *args[] = { &v, 0 };
                QMetaObject::metacall(data, QMetaObject::ReadProperty, prop->coreIndex, args);
                val = v.toString();
            }
        } else {
            val = data->property(name.toUtf8()).toString();
        }
    } else {
        val = data->property(name.toUtf8()).toString();
    }

    if (tempData)
        delete data;

    return val;
}

QVariant QDeclarativeVisualDataModel::evaluate(int index, const QString &expression, QObject *objectContext)
{
    Q_D(QDeclarativeVisualDataModel);
    if (d->m_visualItemModel)
        return d->m_visualItemModel->evaluate(index, expression, objectContext);

    if ((!d->m_listModelInterface && !d->m_abstractItemModel) || !d->m_delegate)
        return QVariant();

    QVariant value;
    QObject *nobj = d->m_cache.item(index);
    if (nobj) {
        QDeclarativeItem *item = qobject_cast<QDeclarativeItem *>(nobj);
        if (item) {
            QDeclarativeExpression e(qmlContext(item), expression, objectContext);
            value = e.value();
        }
    } else {
        QDeclarativeContext *ccontext = d->m_context;
        if (!ccontext) ccontext = qmlContext(this);
        QDeclarativeContext *ctxt = new QDeclarativeContext(ccontext);
        QDeclarativeVisualDataModelData *data = new QDeclarativeVisualDataModelData(index, this);
        ctxt->setContextObject(data);
        QDeclarativeExpression e(ctxt, expression, objectContext);
        value = e.value();
        delete data;
        delete ctxt;
    }

    return value;
}

int QDeclarativeVisualDataModel::indexOf(QDeclarativeItem *item, QObject *) const
{
    QVariant val = QDeclarativeEngine::contextForObject(item)->contextProperty(QLatin1String("index"));
        return val.toInt();
    return -1;
}

void QDeclarativeVisualDataModel::_q_itemsChanged(int index, int count,
                                         const QList<int> &roles)
{
    Q_D(QDeclarativeVisualDataModel);
    // XXX - highly inefficient
    for (int ii = index; ii < index + count; ++ii) {

        if (QObject *item = d->m_cache.item(ii)) {
            QDeclarativeVisualDataModelData *data = d->data(item);

            for (int roleIdx = 0; roleIdx < roles.count(); ++roleIdx) {
                int role = roles.at(roleIdx);
                int propId = data->propForRole(role);
                if (propId != -1) {
                    if (d->m_listModelInterface) {
                        data->setValue(propId, d->m_listModelInterface->data(ii, QList<int>() << role).value(role));
                    } else if (d->m_abstractItemModel) {
                        QModelIndex index = d->m_abstractItemModel->index(ii, 0, d->m_root);
                        data->setValue(propId, d->m_abstractItemModel->data(index, role));
                    }
                }
            }
        }
    }
}

void QDeclarativeVisualDataModel::_q_itemsInserted(int index, int count)
{
    Q_D(QDeclarativeVisualDataModel);
    // XXX - highly inefficient
    QHash<int,QDeclarativeVisualDataModelPrivate::ObjectRef> items;
    for (QHash<int,QDeclarativeVisualDataModelPrivate::ObjectRef>::Iterator iter = d->m_cache.begin();
        iter != d->m_cache.end(); ) {

        if (iter.key() >= index) {
            QDeclarativeVisualDataModelPrivate::ObjectRef objRef = *iter;
            int index = iter.key() + count;
            iter = d->m_cache.erase(iter);

            items.insert(index, objRef);

            QDeclarativeVisualDataModelData *data = d->data(objRef.obj);
            data->setIndex(index);
        } else {
            ++iter;
        }
    }
    d->m_cache.unite(items);

    emit itemsInserted(index, count);
    emit countChanged();
}

void QDeclarativeVisualDataModel::_q_itemsRemoved(int index, int count)
{
    Q_D(QDeclarativeVisualDataModel);
    // XXX - highly inefficient
    QHash<int, QDeclarativeVisualDataModelPrivate::ObjectRef> items;
    for (QHash<int, QDeclarativeVisualDataModelPrivate::ObjectRef>::Iterator iter = d->m_cache.begin();
        iter != d->m_cache.end(); ) {
        if (iter.key() >= index && iter.key() < index + count) {
            QDeclarativeVisualDataModelPrivate::ObjectRef objRef = *iter;
            iter = d->m_cache.erase(iter);
            items.insertMulti(-1, objRef); //XXX perhaps better to maintain separately
            QDeclarativeVisualDataModelData *data = d->data(objRef.obj);
            data->setIndex(-1);
        } else if (iter.key() >= index + count) {
            QDeclarativeVisualDataModelPrivate::ObjectRef objRef = *iter;
            int index = iter.key() - count;
            iter = d->m_cache.erase(iter);
            items.insert(index, objRef);
            QDeclarativeVisualDataModelData *data = d->data(objRef.obj);
            data->setIndex(index);
        } else {
            ++iter;
        }
    }

    d->m_cache.unite(items);
    emit itemsRemoved(index, count);
    emit countChanged();
}

void QDeclarativeVisualDataModel::_q_itemsMoved(int from, int to, int count)
{
    Q_D(QDeclarativeVisualDataModel);
    // XXX - highly inefficient
    QHash<int,QDeclarativeVisualDataModelPrivate::ObjectRef> items;
    for (QHash<int,QDeclarativeVisualDataModelPrivate::ObjectRef>::Iterator iter = d->m_cache.begin();
        iter != d->m_cache.end(); ) {

        if (iter.key() >= from && iter.key() < from + count) {
            QDeclarativeVisualDataModelPrivate::ObjectRef objRef = *iter;
            int index = iter.key() - from + to;
            iter = d->m_cache.erase(iter);

            items.insert(index, objRef);

            QDeclarativeVisualDataModelData *data = d->data(objRef.obj);
            data->setIndex(index);
        } else {
            ++iter;
        }
    }
    for (QHash<int,QDeclarativeVisualDataModelPrivate::ObjectRef>::Iterator iter = d->m_cache.begin();
        iter != d->m_cache.end(); ) {

        int diff = from > to ? count : -count;
        if (iter.key() >= qMin(from,to) && iter.key() < qMax(from+count,to+count)) {
            QDeclarativeVisualDataModelPrivate::ObjectRef objRef = *iter;
            int index = iter.key() + diff;
            iter = d->m_cache.erase(iter);

            items.insert(index, objRef);

            QDeclarativeVisualDataModelData *data = d->data(objRef.obj);
            data->setIndex(index);
        } else {
            ++iter;
        }
    }
    d->m_cache.unite(items);

    emit itemsMoved(from, to, count);
}

void QDeclarativeVisualDataModel::_q_rowsInserted(const QModelIndex &parent, int begin, int end)
{
    if (!parent.isValid())
        _q_itemsInserted(begin, end - begin + 1);
}

void QDeclarativeVisualDataModel::_q_rowsRemoved(const QModelIndex &parent, int begin, int end)
{
    if (!parent.isValid())
        _q_itemsRemoved(begin, end - begin + 1);
}

void QDeclarativeVisualDataModel::_q_rowsMoved(const QModelIndex &sourceParent, int sourceStart, int sourceEnd, const QModelIndex &destinationParent, int destinationRow)
{
    const int count = sourceEnd - sourceStart + 1;
    if (!destinationParent.isValid() && !sourceParent.isValid()) {
        _q_itemsMoved(sourceStart, destinationRow, count);
    } else if (!sourceParent.isValid()) {
        _q_itemsRemoved(sourceStart, count);
    } else if (!destinationParent.isValid()) {
        _q_itemsInserted(destinationRow, count);
    }
}

void QDeclarativeVisualDataModel::_q_dataChanged(const QModelIndex &begin, const QModelIndex &end)
{
    Q_D(QDeclarativeVisualDataModel);
    if (!begin.parent().isValid())
        _q_itemsChanged(begin.row(), end.row() - begin.row() + 1, d->m_roles);
}

void QDeclarativeVisualDataModel::_q_modelReset()
{
    emit modelReset();
}

void QDeclarativeVisualDataModel::_q_createdPackage(int index, QDeclarativePackage *package)
{
    Q_D(QDeclarativeVisualDataModel);
    emit createdItem(index, qobject_cast<QDeclarativeItem*>(package->part(d->m_part)));
}

void QDeclarativeVisualDataModel::_q_destroyingPackage(QDeclarativePackage *package)
{
    Q_D(QDeclarativeVisualDataModel);
    emit destroyingItem(qobject_cast<QDeclarativeItem*>(package->part(d->m_part)));
}

QT_END_NAMESPACE

QML_DECLARE_TYPE(QListModelInterface)

#include <qdeclarativevisualitemmodel.moc>