/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
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** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
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** $QT_END_LICENSE$
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****************************************************************************/

#include "qquicklistmodel_p_p.h"
#include "qquicklistmodelworkeragent_p.h"
#include "qqmlopenmetaobject_p.h"
#include <private/qqmljsast_p.h>
#include <private/qqmljsengine_p.h>

#include <private/qqmlcustomparser_p.h>
#include <private/qqmlscript_p.h>
#include <private/qqmlengine_p.h>
#include <qqmlcontext.h>
#include <qqmlinfo.h>

#include <QtCore/qdebug.h>
#include <QtCore/qstack.h>
#include <QXmlStreamReader>

Q_DECLARE_METATYPE(QListModelInterface *)

QT_BEGIN_NAMESPACE

// Set to 1024 as a debugging aid - easier to distinguish uids from indices of elements/models.
enum { MIN_LISTMODEL_UID = 1024 };

static QAtomicInt uidCounter(MIN_LISTMODEL_UID);

template <typename T>
static bool isMemoryUsed(const char *mem)
{
    for (size_t i=0 ; i < sizeof(T) ; ++i) {
        if (mem[i] != 0)
            return true;
    }

    return false;
}

static QString roleTypeName(ListLayout::Role::DataType t)
{
    QString result;
    const char *roleTypeNames[] = { "String", "Number", "Bool", "List", "QObject", "VariantMap" };

    if (t > ListLayout::Role::Invalid && t < ListLayout::Role::MaxDataType)
        result = QString::fromLatin1(roleTypeNames[t]);

    return result;
}

const ListLayout::Role &ListLayout::getRoleOrCreate(const QString &key, Role::DataType type)
{
    QStringHash<Role *>::Node *node = roleHash.findNode(key);
    if (node) {
        const Role &r = *node->value;
        if (type != r.type)
            qmlInfo(0) << QString::fromLatin1("Can't assign to existing role '%1' of different type [%2 -> %3]").arg(r.name).arg(roleTypeName(type)).arg(roleTypeName(r.type));
        return r;
    }

    return createRole(key, type);
}

const ListLayout::Role &ListLayout::getRoleOrCreate(v8::Handle<v8::String> key, Role::DataType type)
{
    QHashedV8String hashedKey(key);
    QStringHash<Role *>::Node *node = roleHash.findNode(hashedKey);
    if (node) {
        const Role &r = *node->value;
        if (type != r.type)
            qmlInfo(0) << QString::fromLatin1("Can't assign to existing role '%1' of different type [%2 -> %3]").arg(r.name).arg(roleTypeName(type)).arg(roleTypeName(r.type));
        return r;
    }

    QString qkey;
    qkey.resize(key->Length());
    key->Write(reinterpret_cast<uint16_t*>(qkey.data()));

    return createRole(qkey, type);
}

const ListLayout::Role &ListLayout::createRole(const QString &key, ListLayout::Role::DataType type)
{
    const int dataSizes[] = { sizeof(QString), sizeof(double), sizeof(bool), sizeof(ListModel *), sizeof(QQmlGuard<QObject>), sizeof(QVariantMap) };
    const int dataAlignments[] = { sizeof(QString), sizeof(double), sizeof(bool), sizeof(ListModel *), sizeof(QObject *), sizeof(QVariantMap) };

    Role *r = new Role;
    r->name = key;
    r->type = type;

    if (type == Role::List) {
        r->subLayout = new ListLayout;
    } else {
        r->subLayout = 0;
    }

    int dataSize = dataSizes[type];
    int dataAlignment = dataAlignments[type];

    int dataOffset = (currentBlockOffset + dataAlignment-1) & ~(dataAlignment-1);
    if (dataOffset + dataSize > ListElement::BLOCK_SIZE) {
        r->blockIndex = ++currentBlock;
        r->blockOffset = 0;
        currentBlockOffset = dataSize;
    } else {
        r->blockIndex = currentBlock;
        r->blockOffset = dataOffset;
        currentBlockOffset = dataOffset + dataSize;
    }

    int roleIndex = roles.count();
    r->index = roleIndex;

    roles.append(r);
    roleHash.insert(key, r);

    return *r;
}

ListLayout::ListLayout(const ListLayout *other) : currentBlock(0), currentBlockOffset(0)
{
    for (int i=0 ; i < other->roles.count() ; ++i) {
        Role *role = new Role(other->roles[i]);
        roles.append(role);
        roleHash.insert(role->name, role);
    }
    currentBlockOffset = other->currentBlockOffset;
    currentBlock = other->currentBlock;
}

ListLayout::~ListLayout()
{
    for (int i=0 ; i < roles.count() ; ++i) {
        delete roles[i];
    }
}

void ListLayout::sync(ListLayout *src, ListLayout *target)
{
    int roleOffset = target->roles.count();
    int newRoleCount = src->roles.count() - roleOffset;

    for (int i=0 ; i < newRoleCount ; ++i) {
        Role *role = new Role(src->roles[roleOffset + i]);
        target->roles.append(role);
        target->roleHash.insert(role->name, role);
    }

    target->currentBlockOffset = src->currentBlockOffset;
    target->currentBlock = src->currentBlock;
}

ListLayout::Role::Role(const Role *other)
{
    name = other->name;
    type = other->type;
    blockIndex = other->blockIndex;
    blockOffset = other->blockOffset;
    index = other->index;
    if (other->subLayout)
        subLayout = new ListLayout(other->subLayout);
    else
        subLayout = 0;
}

ListLayout::Role::~Role()
{
    delete subLayout;
}

const ListLayout::Role *ListLayout::getRoleOrCreate(const QString &key, const QVariant &data)
{
    Role::DataType type;

    switch (data.type()) {
        case QVariant::Double:      type = Role::Number;      break;
        case QVariant::Int:         type = Role::Number;      break;
        case QVariant::UserType:    type = Role::List;        break;
        case QVariant::Bool:        type = Role::Bool;        break;
        case QVariant::String:      type = Role::String;      break;
        case QVariant::Map:         type = Role::VariantMap;  break;
        default:                    type = Role::Invalid;     break;
    }

    if (type == Role::Invalid) {
        qmlInfo(0) << "Can't create role for unsupported data type";
        return 0;
    }

    return &getRoleOrCreate(key, type);
}

const ListLayout::Role *ListLayout::getExistingRole(const QString &key)
{
    Role *r = 0;
    QStringHash<Role *>::Node *node = roleHash.findNode(key);
    if (node)
        r = node->value;
    return r;
}

const ListLayout::Role *ListLayout::getExistingRole(v8::Handle<v8::String> key)
{
    Role *r = 0;
    QHashedV8String hashedKey(key);
    QStringHash<Role *>::Node *node = roleHash.findNode(hashedKey);
    if (node)
        r = node->value;
    return r;
}

ModelObject *ListModel::getOrCreateModelObject(QQuickListModel *model, int elementIndex)
{
    ListElement *e = elements[elementIndex];
    if (e->m_objectCache == 0) {
        e->m_objectCache = new ModelObject(model, elementIndex);
    }
    return e->m_objectCache;
}

void ListModel::sync(ListModel *src, ListModel *target, QHash<int, ListModel *> *targetModelHash)
{
    // Sanity check
    target->m_uid = src->m_uid;
    if (targetModelHash)
        targetModelHash->insert(target->m_uid, target);

    // Build hash of elements <-> uid for each of the lists
    QHash<int, ElementSync> elementHash;
    for (int i=0 ; i < target->elements.count() ; ++i) {
        ListElement *e = target->elements.at(i);
        int uid = e->getUid();
        ElementSync sync;
        sync.target = e;
        elementHash.insert(uid, sync);
    }
    for (int i=0 ; i < src->elements.count() ; ++i) {
        ListElement *e = src->elements.at(i);
        int uid = e->getUid();

        QHash<int, ElementSync>::iterator it = elementHash.find(uid);
        if (it == elementHash.end()) {
            ElementSync sync;
            sync.src = e;
            elementHash.insert(uid, sync);
        } else {
            ElementSync &sync = it.value();
            sync.src = e;
        }
    }

    // Get list of elements that are in the target but no longer in the source. These get deleted first.
    QHash<int, ElementSync>::iterator it = elementHash.begin();
    QHash<int, ElementSync>::iterator end = elementHash.end();
    while (it != end) {
        const ElementSync &s = it.value();
        if (s.src == 0) {
            s.target->destroy(target->m_layout);
            target->elements.removeOne(s.target);
            delete s.target;
        }
        ++it;
    }

    // Sync the layouts
    ListLayout::sync(src->m_layout, target->m_layout);

    // Clear the target list, and append in correct order from the source
    target->elements.clear();
    for (int i=0 ; i < src->elements.count() ; ++i) {
        ListElement *srcElement = src->elements.at(i);
        it = elementHash.find(srcElement->getUid());
        const ElementSync &s = it.value();
        ListElement *targetElement = s.target;
        if (targetElement == 0) {
            targetElement = new ListElement(srcElement->getUid());
        }
        ListElement::sync(srcElement, src->m_layout, targetElement, target->m_layout, targetModelHash);
        target->elements.append(targetElement);
    }

    target->updateCacheIndices();

    // Update values stored in target meta objects
    for (int i=0 ; i < target->elements.count() ; ++i) {
        ListElement *e = target->elements[i];
        if (e->m_objectCache)
            e->m_objectCache->updateValues();
    }
}

ListModel::ListModel(ListLayout *layout, QQuickListModel *modelCache, int uid) : m_layout(layout), m_modelCache(modelCache)
{
    if (uid == -1)
        uid = uidCounter.fetchAndAddOrdered(1);
    m_uid = uid;
}

void ListModel::destroy()
{
    clear();
    m_uid = -1;
    m_layout = 0;
    if (m_modelCache && m_modelCache->m_primary == false)
        delete m_modelCache;
    m_modelCache = 0;
}

int ListModel::appendElement()
{
    int elementIndex = elements.count();
    newElement(elementIndex);
    return elementIndex;
}

void ListModel::insertElement(int index)
{
    newElement(index);
    updateCacheIndices();
}

void ListModel::move(int from, int to, int n)
{
    if (from > to) {
        // Only move forwards - flip if backwards moving
        int tfrom = from;
        int tto = to;
        from = tto;
        to = tto+n;
        n = tfrom-tto;
    }

    QPODVector<ListElement *, 4> store;
    for (int i=0 ; i < (to-from) ; ++i)
        store.append(elements[from+n+i]);
    for (int i=0 ; i < n ; ++i)
        store.append(elements[from+i]);
    for (int i=0 ; i < store.count() ; ++i)
        elements[from+i] = store[i];

    updateCacheIndices();
}

void ListModel::newElement(int index)
{
    ListElement *e = new ListElement;
    elements.insert(index, e);
}

void ListModel::updateCacheIndices()
{
    for (int i=0 ; i < elements.count() ; ++i) {
        ListElement *e = elements.at(i);
        if (e->m_objectCache) {
            e->m_objectCache->m_elementIndex = i;
        }
    }
}

QVariant ListModel::getProperty(int elementIndex, int roleIndex, const QQuickListModel *owner, QV8Engine *eng)
{
    ListElement *e = elements[elementIndex];
    const ListLayout::Role &r = m_layout->getExistingRole(roleIndex);
    return e->getProperty(r, owner, eng);
}

ListModel *ListModel::getListProperty(int elementIndex, const ListLayout::Role &role)
{
    ListElement *e = elements[elementIndex];
    return e->getListProperty(role);
}

void ListModel::set(int elementIndex, v8::Handle<v8::Object> object, QList<int> *roles, QV8Engine *eng)
{
    ListElement *e = elements[elementIndex];

    v8::Local<v8::Array> propertyNames = object->GetPropertyNames();
    int propertyCount = propertyNames->Length();

    for (int i=0 ; i < propertyCount ; ++i) {
        v8::Local<v8::String> propertyName = propertyNames->Get(i)->ToString();
        v8::Local<v8::Value> propertyValue = object->Get(propertyName);

        // Check if this key exists yet
        int roleIndex = -1;

        // Add the value now
        if (propertyValue->IsString()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::String);
            v8::Handle<v8::String> jsString = propertyValue->ToString();
            QString qstr;
            qstr.resize(jsString->Length());
            jsString->Write(reinterpret_cast<uint16_t*>(qstr.data()));
            roleIndex = e->setStringProperty(r, qstr);
        } else if (propertyValue->IsNumber()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::Number);
            roleIndex = e->setDoubleProperty(r, propertyValue->NumberValue());
        } else if (propertyValue->IsArray()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::List);
            ListModel *subModel = new ListModel(r.subLayout, 0, -1);

            v8::Handle<v8::Array> subArray = v8::Handle<v8::Array>::Cast(propertyValue);
            int arrayLength = subArray->Length();
            for (int j=0 ; j < arrayLength ; ++j) {
                v8::Handle<v8::Object> subObject = subArray->Get(j)->ToObject();
                subModel->append(subObject, eng);
            }

            roleIndex = e->setListProperty(r, subModel);
        } else if (propertyValue->IsBoolean()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::Bool);
            roleIndex = e->setBoolProperty(r, propertyValue->BooleanValue());
        } else if (propertyValue->IsObject()) {
            QV8ObjectResource *r = (QV8ObjectResource *) propertyValue->ToObject()->GetExternalResource();
            if (r && r->resourceType() == QV8ObjectResource::QObjectType) {
                QObject *o = QV8QObjectWrapper::toQObject(r);
                const ListLayout::Role &role = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::QObject);
                if (role.type == ListLayout::Role::QObject)
                    roleIndex = e->setQObjectProperty(role, o);
            } else {
                const ListLayout::Role &role = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::VariantMap);
                if (role.type == ListLayout::Role::VariantMap)
                    roleIndex = e->setVariantMapProperty(role, propertyValue->ToObject(), eng);
            }
        } else if (propertyValue.IsEmpty() || propertyValue->IsUndefined() || propertyValue->IsNull()) {
            const ListLayout::Role *r = m_layout->getExistingRole(propertyName);
            if (r)
                e->clearProperty(*r);
        }

        if (roleIndex != -1)
            roles->append(roleIndex);
    }

    if (e->m_objectCache) {
        e->m_objectCache->updateValues(*roles);
    }
}

void ListModel::set(int elementIndex, v8::Handle<v8::Object> object, QV8Engine *eng)
{
    ListElement *e = elements[elementIndex];

    v8::Local<v8::Array> propertyNames = object->GetPropertyNames();
    int propertyCount = propertyNames->Length();

    for (int i=0 ; i < propertyCount ; ++i) {
        v8::Local<v8::String> propertyName = propertyNames->Get(i)->ToString();
        v8::Local<v8::Value> propertyValue = object->Get(propertyName);

        // Add the value now
        if (propertyValue->IsString()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::String);
            if (r.type == ListLayout::Role::String) {
                v8::Handle<v8::String> jsString = propertyValue->ToString();
                QString qstr;
                qstr.resize(jsString->Length());
                jsString->Write(reinterpret_cast<uint16_t*>(qstr.data()));
                e->setStringPropertyFast(r, qstr);
            }
        } else if (propertyValue->IsNumber()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::Number);
            if (r.type == ListLayout::Role::Number) {
                e->setDoublePropertyFast(r, propertyValue->NumberValue());
            }
        } else if (propertyValue->IsArray()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::List);
            if (r.type == ListLayout::Role::List) {
                ListModel *subModel = new ListModel(r.subLayout, 0, -1);

                v8::Handle<v8::Array> subArray = v8::Handle<v8::Array>::Cast(propertyValue);
                int arrayLength = subArray->Length();
                for (int j=0 ; j < arrayLength ; ++j) {
                    v8::Handle<v8::Object> subObject = subArray->Get(j)->ToObject();
                    subModel->append(subObject, eng);
                }

                e->setListPropertyFast(r, subModel);
            }
        } else if (propertyValue->IsBoolean()) {
            const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::Bool);
            if (r.type == ListLayout::Role::Bool) {
                e->setBoolPropertyFast(r, propertyValue->BooleanValue());
            }
        } else if (propertyValue->IsObject()) {
            QV8ObjectResource *r = (QV8ObjectResource *) propertyValue->ToObject()->GetExternalResource();
            if (r && r->resourceType() == QV8ObjectResource::QObjectType) {
                QObject *o = QV8QObjectWrapper::toQObject(r);
                const ListLayout::Role &r = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::QObject);
                if (r.type == ListLayout::Role::QObject)
                    e->setQObjectPropertyFast(r, o);
            } else {
                const ListLayout::Role &role = m_layout->getRoleOrCreate(propertyName, ListLayout::Role::VariantMap);
                if (role.type == ListLayout::Role::VariantMap)
                    e->setVariantMapFast(role, propertyValue->ToObject(), eng);
            }
        } else if (propertyValue.IsEmpty() || propertyValue->IsUndefined() || propertyValue->IsNull()) {
            const ListLayout::Role *r = m_layout->getExistingRole(propertyName);
            if (r)
                e->clearProperty(*r);
        }
    }
}

void ListModel::clear()
{
    int elementCount = elements.count();
    for (int i=0 ; i < elementCount ; ++i) {
        elements[i]->destroy(m_layout);
        delete elements[i];
    }
    elements.clear();
}

void ListModel::remove(int index, int count)
{
    for (int i=0 ; i < count ; ++i) {
        elements[index+i]->destroy(m_layout);
        delete elements[index+i];
    }
    elements.remove(index, count);
    updateCacheIndices();
}

void ListModel::insert(int elementIndex, v8::Handle<v8::Object> object, QV8Engine *eng)
{
    insertElement(elementIndex);
    set(elementIndex, object, eng);
}

int ListModel::append(v8::Handle<v8::Object> object, QV8Engine *eng)
{
    int elementIndex = appendElement();
    set(elementIndex, object, eng);
    return elementIndex;
}

int ListModel::setOrCreateProperty(int elementIndex, const QString &key, const QVariant &data)
{
    int roleIndex = -1;

    if (elementIndex >= 0 && elementIndex < elements.count()) {
        ListElement *e = elements[elementIndex];

        const ListLayout::Role *r = m_layout->getRoleOrCreate(key, data);
        if (r) {
            roleIndex = e->setVariantProperty(*r, data);

            if (roleIndex != -1 && e->m_objectCache) {
                QList<int> roles;
                roles << roleIndex;
                e->m_objectCache->updateValues(roles);
            }
        }
    }

    return roleIndex;
}

int ListModel::setExistingProperty(int elementIndex, const QString &key, v8::Handle<v8::Value> data, QV8Engine *eng)
{
    int roleIndex = -1;

    if (elementIndex >= 0 && elementIndex < elements.count()) {
        ListElement *e = elements[elementIndex];
        const ListLayout::Role *r = m_layout->getExistingRole(key);
        if (r)
            roleIndex = e->setJsProperty(*r, data, eng);
    }

    return roleIndex;
}

inline char *ListElement::getPropertyMemory(const ListLayout::Role &role)
{
    ListElement *e = this;
    int blockIndex = 0;
    while (blockIndex < role.blockIndex) {
        if (e->next == 0) {
            e->next = new ListElement;
            e->next->uid = uid;
        }
        e = e->next;
        ++blockIndex;
    }

    char *mem = &e->data[role.blockOffset];
    return mem;
}

QString *ListElement::getStringProperty(const ListLayout::Role &role)
{
    char *mem = getPropertyMemory(role);
    QString *s = reinterpret_cast<QString *>(mem);
    return s->data_ptr() ? s : 0;
}

QObject *ListElement::getQObjectProperty(const ListLayout::Role &role)
{
    char *mem = getPropertyMemory(role);
    QQmlGuard<QObject> *o = reinterpret_cast<QQmlGuard<QObject> *>(mem);
    return o->data();
}

QVariantMap *ListElement::getVariantMapProperty(const ListLayout::Role &role)
{
    QVariantMap *map = 0;

    char *mem = getPropertyMemory(role);
    if (isMemoryUsed<QVariantMap>(mem))
        map = reinterpret_cast<QVariantMap *>(mem);

    return map;
}

QQmlGuard<QObject> *ListElement::getGuardProperty(const ListLayout::Role &role)
{
    char *mem = getPropertyMemory(role);

    bool existingGuard = false;
    for (size_t i=0 ; i < sizeof(QQmlGuard<QObject>) ; ++i) {
        if (mem[i] != 0) {
            existingGuard = true;
            break;
        }
    }

    QQmlGuard<QObject> *o = 0;

    if (existingGuard)
        o = reinterpret_cast<QQmlGuard<QObject> *>(mem);

    return o;
}

ListModel *ListElement::getListProperty(const ListLayout::Role &role)
{
    char *mem = getPropertyMemory(role);
    ListModel **value = reinterpret_cast<ListModel **>(mem);
    return *value;
}

QVariant ListElement::getProperty(const ListLayout::Role &role, const QQuickListModel *owner, QV8Engine *eng)
{
    char *mem = getPropertyMemory(role);

    QVariant data;

    switch (role.type) {
        case ListLayout::Role::Number:
            {
                double *value = reinterpret_cast<double *>(mem);
                data = *value;
            }
            break;
        case ListLayout::Role::String:
            {
                QString *value = reinterpret_cast<QString *>(mem);
                if (value->data_ptr() != 0)
                    data = *value;
            }
            break;
        case ListLayout::Role::Bool:
            {
                bool *value = reinterpret_cast<bool *>(mem);
                data = *value;
            }
            break;
        case ListLayout::Role::List:
            {
                ListModel **value = reinterpret_cast<ListModel **>(mem);
                ListModel *model = *value;

                if (model) {
                    if (model->m_modelCache == 0) {
                        model->m_modelCache = new QQuickListModel(owner, model, eng);
                        QQmlEngine::setContextForObject(model->m_modelCache, QQmlEngine::contextForObject(owner));
                    }

                    QObject *object = model->m_modelCache;
                    data = QVariant::fromValue(object);
                }
            }
            break;
        case ListLayout::Role::QObject:
            {
                QQmlGuard<QObject> *guard = reinterpret_cast<QQmlGuard<QObject> *>(mem);
                QObject *object = guard->data();
                if (object)
                    data = QVariant::fromValue(object);
            }
            break;
        case ListLayout::Role::VariantMap:
            {
                if (isMemoryUsed<QVariantMap>(mem)) {
                    QVariantMap *map = reinterpret_cast<QVariantMap *>(mem);
                    data = *map;
                }
            }
            break;
        default:
            break;
    }

    return data;
}

int ListElement::setStringProperty(const ListLayout::Role &role, const QString &s)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::String) {
        char *mem = getPropertyMemory(role);
        QString *c = reinterpret_cast<QString *>(mem);
        bool changed;
        if (c->data_ptr() == 0) {
            new (mem) QString(s);
            changed = true;
        } else {
            changed = c->compare(s) != 0;
            *c = s;
        }
        if (changed)
            roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setDoubleProperty(const ListLayout::Role &role, double d)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::Number) {
        char *mem = getPropertyMemory(role);
        double *value = new (mem) double;
        bool changed = *value != d;
        *value = d;
        if (changed)
            roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setBoolProperty(const ListLayout::Role &role, bool b)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::Bool) {
        char *mem = getPropertyMemory(role);
        bool *value = new (mem) bool;
        bool changed = *value != b;
        *value = b;
        if (changed)
            roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setListProperty(const ListLayout::Role &role, ListModel *m)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::List) {
        char *mem = getPropertyMemory(role);
        ListModel **value = new (mem) ListModel *;
        if (*value) {
            (*value)->destroy();
            delete *value;
        }
        *value = m;
        roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setQObjectProperty(const ListLayout::Role &role, QObject *o)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::QObject) {
        char *mem = getPropertyMemory(role);
        QQmlGuard<QObject> *g = reinterpret_cast<QQmlGuard<QObject> *>(mem);
        bool existingGuard = false;
        for (size_t i=0 ; i < sizeof(QQmlGuard<QObject>) ; ++i) {
            if (mem[i] != 0) {
                existingGuard = true;
                break;
            }
        }
        bool changed;
        if (existingGuard) {
            changed = g->data() != o;
            g->~QQmlGuard();
        } else {
            changed = true;
        }
        new (mem) QQmlGuard<QObject>(o);
        if (changed)
            roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setVariantMapProperty(const ListLayout::Role &role, v8::Handle<v8::Object> o, QV8Engine *eng)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::VariantMap) {
        char *mem = getPropertyMemory(role);
        if (isMemoryUsed<QVariantMap>(mem)) {
            QVariantMap *map = reinterpret_cast<QVariantMap *>(mem);
            map->~QMap();
        }
        new (mem) QVariantMap(eng->variantMapFromJS(o));
        roleIndex = role.index;
    }

    return roleIndex;
}

int ListElement::setVariantMapProperty(const ListLayout::Role &role, QVariantMap *m)
{
    int roleIndex = -1;

    if (role.type == ListLayout::Role::VariantMap) {
        char *mem = getPropertyMemory(role);
        if (isMemoryUsed<QVariantMap>(mem)) {
            QVariantMap *map = reinterpret_cast<QVariantMap *>(mem);
            map->~QMap();
        }
        if (m)
            new (mem) QVariantMap(*m);
        else
            new (mem) QVariantMap;
        roleIndex = role.index;
    }

    return roleIndex;
}

void ListElement::setStringPropertyFast(const ListLayout::Role &role, const QString &s)
{
    char *mem = getPropertyMemory(role);
    new (mem) QString(s);
}

void ListElement::setDoublePropertyFast(const ListLayout::Role &role, double d)
{
    char *mem = getPropertyMemory(role);
    double *value = new (mem) double;
    *value = d;
}

void ListElement::setBoolPropertyFast(const ListLayout::Role &role, bool b)
{
    char *mem = getPropertyMemory(role);
    bool *value = new (mem) bool;
    *value = b;
}

void ListElement::setQObjectPropertyFast(const ListLayout::Role &role, QObject *o)
{
    char *mem = getPropertyMemory(role);
    new (mem) QQmlGuard<QObject>(o);
}

void ListElement::setListPropertyFast(const ListLayout::Role &role, ListModel *m)
{
    char *mem = getPropertyMemory(role);
    ListModel **value = new (mem) ListModel *;
    *value = m;
}

void ListElement::setVariantMapFast(const ListLayout::Role &role, v8::Handle<v8::Object> o, QV8Engine *eng)
{
    char *mem = getPropertyMemory(role);
    QVariantMap *map = new (mem) QVariantMap;
    *map = eng->variantMapFromJS(o);
}

void ListElement::clearProperty(const ListLayout::Role &role)
{
    switch (role.type) {
    case ListLayout::Role::String:
        setStringProperty(role, QString());
        break;
    case ListLayout::Role::Number:
        setDoubleProperty(role, 0.0);
        break;
    case ListLayout::Role::Bool:
        setBoolProperty(role, false);
        break;
    case ListLayout::Role::List:
        setListProperty(role, 0);
        break;
    case ListLayout::Role::QObject:
        setQObjectProperty(role, 0);
        break;
    case ListLayout::Role::VariantMap:
        setVariantMapProperty(role, 0);
        break;
    default:
        break;
    }
}

ListElement::ListElement()
{
    m_objectCache = 0;
    uid = uidCounter.fetchAndAddOrdered(1);
    next = 0;
    qMemSet(data, 0, sizeof(data));
}

ListElement::ListElement(int existingUid)
{
    m_objectCache = 0;
    uid = existingUid;
    next = 0;
    qMemSet(data, 0, sizeof(data));
}

ListElement::~ListElement()
{
    delete next;
}

void ListElement::sync(ListElement *src, ListLayout *srcLayout, ListElement *target, ListLayout *targetLayout, QHash<int, ListModel *> *targetModelHash)
{
    for (int i=0 ; i < srcLayout->roleCount() ; ++i) {
        const ListLayout::Role &srcRole = srcLayout->getExistingRole(i);
        const ListLayout::Role &targetRole = targetLayout->getExistingRole(i);

        switch (srcRole.type) {
            case ListLayout::Role::List:
                {
                    ListModel *srcSubModel = src->getListProperty(srcRole);
                    ListModel *targetSubModel = target->getListProperty(targetRole);

                    if (srcSubModel) {
                        if (targetSubModel == 0) {
                            targetSubModel = new ListModel(targetRole.subLayout, 0, srcSubModel->getUid());
                            target->setListPropertyFast(targetRole, targetSubModel);
                        }
                        ListModel::sync(srcSubModel, targetSubModel, targetModelHash);
                    }
                }
                break;
            case ListLayout::Role::QObject:
                {
                    QObject *object = src->getQObjectProperty(srcRole);
                    target->setQObjectProperty(targetRole, object);
                }
                break;
            case ListLayout::Role::String:
            case ListLayout::Role::Number:
            case ListLayout::Role::Bool:
                {
                    QVariant v = src->getProperty(srcRole, 0, 0);
                    target->setVariantProperty(targetRole, v);
                }
            case ListLayout::Role::VariantMap:
                {
                    QVariantMap *map = src->getVariantMapProperty(srcRole);
                    target->setVariantMapProperty(targetRole, map);
                }
                break;
            default:
                break;
        }
    }

}

void ListElement::destroy(ListLayout *layout)
{
    if (layout) {
        for (int i=0 ; i < layout->roleCount() ; ++i) {
            const ListLayout::Role &r = layout->getExistingRole(i);

            switch (r.type) {
                case ListLayout::Role::String:
                    {
                        QString *string = getStringProperty(r);
                        if (string)
                            string->~QString();
                    }
                    break;
                case ListLayout::Role::List:
                    {
                        ListModel *model = getListProperty(r);
                        if (model) {
                            model->destroy();
                            delete model;
                        }
                    }
                    break;
                case ListLayout::Role::QObject:
                    {
                        QQmlGuard<QObject> *guard = getGuardProperty(r);
                        if (guard)
                            guard->~QQmlGuard();
                    }
                    break;
                case ListLayout::Role::VariantMap:
                    {
                        QVariantMap *map = getVariantMapProperty(r);
                        if (map)
                            map->~QMap();
                    }
                    break;
                default:
                    // other types don't need explicit cleanup.
                    break;
            }
        }

        delete m_objectCache;
    }

    if (next)
        next->destroy(0);
    uid = -1;
}

int ListElement::setVariantProperty(const ListLayout::Role &role, const QVariant &d)
{
    int roleIndex = -1;

    switch (role.type) {
        case ListLayout::Role::Number:
            roleIndex = setDoubleProperty(role, d.toDouble());
            break;
        case ListLayout::Role::String:
            roleIndex = setStringProperty(role, d.toString());
            break;
        case ListLayout::Role::Bool:
            roleIndex = setBoolProperty(role, d.toBool());
            break;
        case ListLayout::Role::List:
            roleIndex = setListProperty(role, d.value<ListModel *>());
            break;
        case ListLayout::Role::VariantMap: {
                QVariantMap map = d.toMap();
                roleIndex = setVariantMapProperty(role, &map);
            }
            break;
        default:
            break;
    }

    return roleIndex;
}

int ListElement::setJsProperty(const ListLayout::Role &role, v8::Handle<v8::Value> d, QV8Engine *eng)
{
    // Check if this key exists yet
    int roleIndex = -1;

    // Add the value now
    if (d->IsString()) {
        v8::Handle<v8::String> jsString = d->ToString();
        QString qstr;
        qstr.resize(jsString->Length());
        jsString->Write(reinterpret_cast<uint16_t*>(qstr.data()));
        roleIndex = setStringProperty(role, qstr);
    } else if (d->IsNumber()) {
        roleIndex = setDoubleProperty(role, d->NumberValue());
    } else if (d->IsArray()) {
        ListModel *subModel = new ListModel(role.subLayout, 0, -1);
        v8::Handle<v8::Array> subArray = v8::Handle<v8::Array>::Cast(d);
        int arrayLength = subArray->Length();
        for (int j=0 ; j < arrayLength ; ++j) {
            v8::Handle<v8::Object> subObject = subArray->Get(j)->ToObject();
            subModel->append(subObject, eng);
        }
        roleIndex = setListProperty(role, subModel);
    } else if (d->IsBoolean()) {
        roleIndex = setBoolProperty(role, d->BooleanValue());
    } else if (d->IsObject()) {
        QV8ObjectResource *r = (QV8ObjectResource *) d->ToObject()->GetExternalResource();
        if (role.type == ListLayout::Role::QObject && r && r->resourceType() == QV8ObjectResource::QObjectType) {
            QObject *o = QV8QObjectWrapper::toQObject(r);
            roleIndex = setQObjectProperty(role, o);
        } else if (role.type == ListLayout::Role::VariantMap) {
            roleIndex = setVariantMapProperty(role, d->ToObject(), eng);
        }
    } else if (d.IsEmpty() || d->IsUndefined() || d->IsNull()) {
        clearProperty(role);
    }

    return roleIndex;
}

ModelObject::ModelObject(QQuickListModel *model, int elementIndex)
: m_model(model), m_elementIndex(elementIndex), m_meta(new ModelNodeMetaObject(this))
{
    updateValues();
    setNodeUpdatesEnabled(true);
}

void ModelObject::updateValues()
{
    int roleCount = m_model->m_listModel->roleCount();
    for (int i=0 ; i < roleCount ; ++i) {
        const ListLayout::Role &role = m_model->m_listModel->getExistingRole(i);
        QByteArray name = role.name.toUtf8();
        const QVariant &data = m_model->data(m_elementIndex, i);
        setValue(name, data, role.type == ListLayout::Role::List);
    }
}

void ModelObject::updateValues(const QList<int> &roles)
{
    int roleCount = roles.count();
    for (int i=0 ; i < roleCount ; ++i) {
        int roleIndex = roles.at(i);
        const ListLayout::Role &role = m_model->m_listModel->getExistingRole(roleIndex);
        QByteArray name = role.name.toUtf8();
        const QVariant &data = m_model->data(m_elementIndex, roleIndex);
        setValue(name, data, role.type == ListLayout::Role::List);
    }
}

ModelNodeMetaObject::ModelNodeMetaObject(ModelObject *object)
: QQmlOpenMetaObject(object), m_enabled(false), m_obj(object)
{
}

ModelNodeMetaObject::~ModelNodeMetaObject()
{
}

void ModelNodeMetaObject::propertyWritten(int index)
{
    if (!m_enabled)
        return;

    QV8Engine *eng = m_obj->m_model->engine();

    QString propName = QString::fromUtf8(name(index));
    QVariant value = operator[](index);

    v8::HandleScope handle_scope;
    v8::Context::Scope scope(eng->context());

    v8::Handle<v8::Value> v = eng->fromVariant(value);

    int roleIndex = m_obj->m_model->m_listModel->setExistingProperty(m_obj->m_elementIndex, propName, v, eng);
    if (roleIndex != -1) {
        QList<int> roles;
        roles << roleIndex;
        m_obj->m_model->emitItemsChanged(m_obj->m_elementIndex, 1, roles);
    }
}

DynamicRoleModelNode::DynamicRoleModelNode(QQuickListModel *owner, int uid) : m_owner(owner), m_uid(uid), m_meta(new DynamicRoleModelNodeMetaObject(this))
{
    setNodeUpdatesEnabled(true);
}

DynamicRoleModelNode *DynamicRoleModelNode::create(const QVariantMap &obj, QQuickListModel *owner)
{
    DynamicRoleModelNode *object = new DynamicRoleModelNode(owner, uidCounter.fetchAndAddOrdered(1));
    QList<int> roles;
    object->updateValues(obj, roles);
    return object;
}

void DynamicRoleModelNode::sync(DynamicRoleModelNode *src, DynamicRoleModelNode *target, QHash<int, QQuickListModel *> *targetModelHash)
{
    for (int i=0 ; i < src->m_meta->count() ; ++i) {
        const QByteArray &name = src->m_meta->name(i);
        QVariant value = src->m_meta->value(i);

        QQuickListModel *srcModel = qobject_cast<QQuickListModel *>(value.value<QObject *>());
        QQuickListModel *targetModel = qobject_cast<QQuickListModel *>(target->m_meta->value(i).value<QObject *>());

        if (srcModel) {
            if (targetModel == 0)
                targetModel = QQuickListModel::createWithOwner(target->m_owner);

            QQuickListModel::sync(srcModel, targetModel, targetModelHash);

            QObject *targetModelObject = targetModel;
            value = QVariant::fromValue(targetModelObject);
        } else if (targetModel) {
            delete targetModel;
        }

        target->setValue(name, value);
    }
}

void DynamicRoleModelNode::updateValues(const QVariantMap &object, QList<int> &roles)
{
    const QList<QString> &keys = object.keys();

    QList<QString>::const_iterator it = keys.begin();
    QList<QString>::const_iterator end = keys.end();

    while (it != end) {
        const QString &key = *it;

        int roleIndex = m_owner->m_roles.indexOf(key);
        if (roleIndex == -1) {
            roleIndex = m_owner->m_roles.count();
            m_owner->m_roles.append(key);
        }

        QVariant value = object[key];

        if (value.type() == QVariant::List) {
            QQuickListModel *subModel = QQuickListModel::createWithOwner(m_owner);

            QVariantList subArray = value.toList();
            QVariantList::const_iterator subIt = subArray.begin();
            QVariantList::const_iterator subEnd = subArray.end();
            while (subIt != subEnd) {
                const QVariantMap &subObject = subIt->toMap();
                subModel->m_modelObjects.append(DynamicRoleModelNode::create(subObject, subModel));
                ++subIt;
            }

            QObject *subModelObject = subModel;
            value = QVariant::fromValue(subModelObject);
        }

        const QByteArray &keyUtf8 = key.toUtf8();

        QQuickListModel *existingModel = qobject_cast<QQuickListModel *>(m_meta->value(keyUtf8).value<QObject *>());
        if (existingModel)
            delete existingModel;

        if (m_meta->setValue(keyUtf8, value))
            roles << roleIndex;

        ++it;
    }
}

DynamicRoleModelNodeMetaObject::DynamicRoleModelNodeMetaObject(DynamicRoleModelNode *object)
    : QQmlOpenMetaObject(object), m_enabled(false), m_owner(object)
{
}

DynamicRoleModelNodeMetaObject::~DynamicRoleModelNodeMetaObject()
{
    for (int i=0 ; i < count() ; ++i) {
        QQuickListModel *subModel = qobject_cast<QQuickListModel *>(value(i).value<QObject *>());
        if (subModel)
            delete subModel;
    }
}

void DynamicRoleModelNodeMetaObject::propertyWrite(int index)
{
    if (!m_enabled)
        return;

    QVariant v = value(index);
    QQuickListModel *model = qobject_cast<QQuickListModel *>(v.value<QObject *>());
    if (model)
        delete model;
}

void DynamicRoleModelNodeMetaObject::propertyWritten(int index)
{
    if (!m_enabled)
        return;

    QQuickListModel *parentModel = m_owner->m_owner;

    QVariant v = value(index);
    if (v.type() == QVariant::List) {
        QQuickListModel *subModel = QQuickListModel::createWithOwner(parentModel);

        QVariantList subArray = v.toList();
        QVariantList::const_iterator subIt = subArray.begin();
        QVariantList::const_iterator subEnd = subArray.end();
        while (subIt != subEnd) {
            const QVariantMap &subObject = subIt->toMap();
            subModel->m_modelObjects.append(DynamicRoleModelNode::create(subObject, subModel));
            ++subIt;
        }

        QObject *subModelObject = subModel;
        v = QVariant::fromValue(subModelObject);

        setValue(index, v);
    }

    int elementIndex = parentModel->m_modelObjects.indexOf(m_owner);
    int roleIndex = parentModel->m_roles.indexOf(QString::fromLatin1(name(index).constData()));

    if (elementIndex != -1 && roleIndex != -1) {
        QList<int> roles;
        roles << roleIndex;

        parentModel->emitItemsChanged(elementIndex, 1, roles);
    }
}

QQuickListModelParser::ListInstruction *QQuickListModelParser::ListModelData::instructions() const
{
    return (QQuickListModelParser::ListInstruction *)((char *)this + sizeof(ListModelData));
}

/*!
    \qmlclass ListModel QQuickListModel
    \inqmlmodule QtQuick 2
    \ingroup qml-working-with-data
    \brief The ListModel element defines a free-form list data source.

    The ListModel is a simple container of ListElement definitions, each containing data roles.
    The contents can be defined dynamically, or explicitly in QML.

    The number of elements in the model can be obtained from its \l count property.
    A number of familiar methods are also provided to manipulate the contents of the
    model, including append(), insert(), move(), remove() and set(). These methods
    accept dictionaries as their arguments; these are translated to ListElement objects
    by the model.

    Elements can be manipulated via the model using the setProperty() method, which
    allows the roles of the specified element to be set and changed.

    \section1 Example Usage

    The following example shows a ListModel containing three elements, with the roles
    "name" and "cost".

    \div {class="float-right"}
    \inlineimage listmodel.png
    \enddiv

    \snippet doc/src/snippets/qml/listmodel.qml 0

    \clearfloat
    Roles (properties) in each element must begin with a lower-case letter and
    should be common to all elements in a model. The ListElement documentation
    provides more guidelines for how elements should be defined.

    Since the example model contains an \c id property, it can be referenced
    by views, such as the ListView in this example:

    \snippet doc/src/snippets/qml/listmodel-simple.qml 0
    \dots 8
    \snippet doc/src/snippets/qml/listmodel-simple.qml 1

    It is possible for roles to contain list data.  In the following example we
    create a list of fruit attributes:

    \snippet doc/src/snippets/qml/listmodel-nested.qml model

    The delegate displays all the fruit attributes:

    \div {class="float-right"}
    \inlineimage listmodel-nested.png
    \enddiv

    \snippet doc/src/snippets/qml/listmodel-nested.qml delegate

    \clearfloat
    \section1 Modifying List Models

    The content of a ListModel may be created and modified using the clear(),
    append(), set(), insert() and setProperty() methods.  For example:

    \snippet doc/src/snippets/qml/listmodel-modify.qml delegate

    Note that when creating content dynamically the set of available properties
    cannot be changed once set. Whatever properties are first added to the model
    are the only permitted properties in the model.

    \section1 Using Threaded List Models with WorkerScript

    ListModel can be used together with WorkerScript access a list model
    from multiple threads. This is useful if list modifications are
    synchronous and take some time: the list operations can be moved to a
    different thread to avoid blocking of the main GUI thread.

    Here is an example that uses WorkerScript to periodically append the
    current time to a list model:

    \snippet examples/declarative/threading/threadedlistmodel/timedisplay.qml 0

    The included file, \tt dataloader.js, looks like this:

    \snippet examples/declarative/threading/threadedlistmodel/dataloader.js 0

    The timer in the main example sends messages to the worker script by calling
    \l WorkerScript::sendMessage(). When this message is received,
    \l{WorkerScript::onMessage}{WorkerScript.onMessage()} is invoked in \c dataloader.js,
    which appends the current time to the list model.

    Note the call to sync() from the \l{WorkerScript::onMessage}{WorkerScript.onMessage()}
    handler. You must call sync() or else the changes made to the list from the external
    thread will not be reflected in the list model in the main thread.

    \sa {qmlmodels}{Data Models}, {declarative/threading/threadedlistmodel}{Threaded ListModel example}, QtQml
*/

QQuickListModel::QQuickListModel(QObject *parent)
: QListModelInterface(parent)
{
    m_mainThread = true;
    m_primary = true;
    m_agent = 0;
    m_uid = uidCounter.fetchAndAddOrdered(1);
    m_dynamicRoles = false;

    m_layout = new ListLayout;
    m_listModel = new ListModel(m_layout, this, -1);

    m_engine = 0;
}

QQuickListModel::QQuickListModel(const QQuickListModel *owner, ListModel *data, QV8Engine *eng, QObject *parent)
: QListModelInterface(parent)
{
    m_mainThread = owner->m_mainThread;
    m_primary = false;
    m_agent = owner->m_agent;

    Q_ASSERT(owner->m_dynamicRoles == false);
    m_dynamicRoles = false;
    m_layout = 0;
    m_listModel = data;

    m_engine = eng;
}

QQuickListModel::QQuickListModel(QQuickListModel *orig, QQuickListModelWorkerAgent *agent)
: QListModelInterface(agent)
{
    m_mainThread = false;
    m_primary = true;
    m_agent = agent;
    m_dynamicRoles = orig->m_dynamicRoles;

    m_layout = new ListLayout(orig->m_layout);
    m_listModel = new ListModel(m_layout, this, orig->m_listModel->getUid());

    if (m_dynamicRoles)
        sync(orig, this, 0);
    else
        ListModel::sync(orig->m_listModel, m_listModel, 0);

    m_engine = 0;
}

QQuickListModel::~QQuickListModel()
{
    for (int i=0 ; i < m_modelObjects.count() ; ++i)
        delete m_modelObjects[i];

    if (m_primary) {
        m_listModel->destroy();
        delete m_listModel;

        if (m_mainThread && m_agent) {
            m_agent->modelDestroyed();
            m_agent->release();
        }
    }

    m_listModel = 0;

    delete m_layout;
    m_layout = 0;
}

QQuickListModel *QQuickListModel::createWithOwner(QQuickListModel *newOwner)
{
    QQuickListModel *model = new QQuickListModel;

    model->m_mainThread = newOwner->m_mainThread;
    model->m_engine = newOwner->m_engine;
    model->m_agent = newOwner->m_agent;
    model->m_dynamicRoles = newOwner->m_dynamicRoles;

    if (model->m_mainThread && model->m_agent)
        model->m_agent->addref();

    QQmlEngine::setContextForObject(model, QQmlEngine::contextForObject(newOwner));

    return model;
}

QV8Engine *QQuickListModel::engine() const
{
    if (m_engine == 0) {
        m_engine  = QQmlEnginePrivate::getV8Engine(qmlEngine(this));
    }

    return m_engine;
}

void QQuickListModel::sync(QQuickListModel *src, QQuickListModel *target, QHash<int, QQuickListModel *> *targetModelHash)
{
    Q_ASSERT(src->m_dynamicRoles && target->m_dynamicRoles);

    target->m_uid = src->m_uid;
    if (targetModelHash)
        targetModelHash->insert(target->m_uid, target);
    target->m_roles = src->m_roles;

    // Build hash of elements <-> uid for each of the lists
    QHash<int, ElementSync> elementHash;
    for (int i=0 ; i < target->m_modelObjects.count() ; ++i) {
        DynamicRoleModelNode *e = target->m_modelObjects.at(i);
        int uid = e->getUid();
        ElementSync sync;
        sync.target = e;
        elementHash.insert(uid, sync);
    }
    for (int i=0 ; i < src->m_modelObjects.count() ; ++i) {
        DynamicRoleModelNode *e = src->m_modelObjects.at(i);
        int uid = e->getUid();

        QHash<int, ElementSync>::iterator it = elementHash.find(uid);
        if (it == elementHash.end()) {
            ElementSync sync;
            sync.src = e;
            elementHash.insert(uid, sync);
        } else {
            ElementSync &sync = it.value();
            sync.src = e;
        }
    }

    // Get list of elements that are in the target but no longer in the source. These get deleted first.
    QHash<int, ElementSync>::iterator it = elementHash.begin();
    QHash<int, ElementSync>::iterator end = elementHash.end();
    while (it != end) {
        const ElementSync &s = it.value();
        if (s.src == 0) {
            int targetIndex = target->m_modelObjects.indexOf(s.target);
            target->m_modelObjects.remove(targetIndex, 1);
            delete s.target;
        }
        ++it;
    }

    // Clear the target list, and append in correct order from the source
    target->m_modelObjects.clear();
    for (int i=0 ; i < src->m_modelObjects.count() ; ++i) {
        DynamicRoleModelNode *srcElement = src->m_modelObjects.at(i);
        it = elementHash.find(srcElement->getUid());
        const ElementSync &s = it.value();
        DynamicRoleModelNode *targetElement = s.target;
        if (targetElement == 0) {
            targetElement = new DynamicRoleModelNode(target, srcElement->getUid());
        }
        DynamicRoleModelNode::sync(srcElement, targetElement, targetModelHash);
        target->m_modelObjects.append(targetElement);
    }
}

void QQuickListModel::emitItemsChanged(int index, int count, const QList<int> &roles)
{
    if (m_mainThread) {
        emit itemsChanged(index, count, roles);
    } else {
        int uid = m_dynamicRoles ? getUid() : m_listModel->getUid();
        m_agent->data.changedChange(uid, index, count, roles);
    }
}

void QQuickListModel::emitItemsRemoved(int index, int count)
{
    if (m_mainThread) {
        emit itemsRemoved(index, count);
        emit countChanged();
    } else {
        int uid = m_dynamicRoles ? getUid() : m_listModel->getUid();
        if (index == 0 && count == this->count())
            m_agent->data.clearChange(uid);
        m_agent->data.removeChange(uid, index, count);
    }
}

void QQuickListModel::emitItemsInserted(int index, int count)
{
    if (m_mainThread) {
        emit itemsInserted(index, count);
        emit countChanged();
    } else {
        int uid = m_dynamicRoles ? getUid() : m_listModel->getUid();
        m_agent->data.insertChange(uid, index, count);
    }
}

void QQuickListModel::emitItemsMoved(int from, int to, int n)
{
    if (m_mainThread) {
        emit itemsMoved(from, to, n);
    } else {
        int uid = m_dynamicRoles ? getUid() : m_listModel->getUid();
        m_agent->data.moveChange(uid, from, n, to);
    }
}

QQuickListModelWorkerAgent *QQuickListModel::agent()
{
    if (m_agent)
        return m_agent;

    m_agent = new QQuickListModelWorkerAgent(this);
    return m_agent;
}

QList<int> QQuickListModel::roles() const
{
    QList<int> rolesArray;

    if (m_dynamicRoles) {
        for (int i=0 ; i < m_roles.count() ; ++i)
            rolesArray << i;
    } else {
        for (int i=0 ; i < m_listModel->roleCount() ; ++i)
            rolesArray << i;
    }

    return rolesArray;
}

QString QQuickListModel::toString(int role) const
{
    QString roleName;

    if (m_dynamicRoles) {
        roleName = m_roles[role];
    } else {
        const ListLayout::Role &r = m_listModel->getExistingRole(role);
        roleName = r.name;
    }

    return roleName;
}

QVariant QQuickListModel::data(int index, int role) const
{
    QVariant v;

    if (index >= count() || index < 0)
        return v;

    if (m_dynamicRoles)
        v = m_modelObjects[index]->getValue(m_roles[role]);
    else
        v = m_listModel->getProperty(index, role, this, engine());

    return v;
}

/*!
    \qmlproperty bool QtQuick2::ListModel::dynamicRoles

    By default, the type of a role is fixed the first time
    the role is used. For example, if you create a role called
    "data" and assign a number to it, you can no longer assign
    a string to the "data" role. However, when the dynamicRoles
    property is enabled, the type of a given role is not fixed
    and can be different between elements.

    The dynamicRoles property must be set before any data is
    added to the ListModel, and must be set from the main
    thread.

    A ListModel that has data statically defined (via the
    ListElement QML syntax) cannot have the dynamicRoles
    property enabled.

    There is a significant performance cost to using a
    ListModel with dynamic roles enabled. The cost varies
    from platform to platform but is typically somewhere
    between 4-6x slower than using static role types.

    Due to the performance cost of using dynamic roles,
    they are disabled by default.
*/
void QQuickListModel::setDynamicRoles(bool enableDynamicRoles)
{
    if (m_mainThread && m_agent == 0) {
        if (enableDynamicRoles) {
            if (m_layout->roleCount())
                qmlInfo(this) << tr("unable to enable dynamic roles as this model is not empty!");
            else
                m_dynamicRoles = true;
        } else {
            if (m_roles.count()) {
                qmlInfo(this) << tr("unable to enable static roles as this model is not empty!");
            } else {
                m_dynamicRoles = false;
            }
        }
    } else {
        qmlInfo(this) << tr("dynamic role setting must be made from the main thread, before any worker scripts are created");
    }
}

/*!
    \qmlproperty int QtQuick2::ListModel::count
    The number of data entries in the model.
*/
int QQuickListModel::count() const
{
    int count;

    if (m_dynamicRoles)
        count = m_modelObjects.count();
    else {
        count = m_listModel->elementCount();
    }

    return count;
}

/*!
    \qmlmethod QtQuick2::ListModel::clear()

    Deletes all content from the model.

    \sa append() remove()
*/
void QQuickListModel::clear()
{
    int cleared = count();

    if (m_dynamicRoles) {
        for (int i=0 ; i < m_modelObjects.count() ; ++i)
            delete m_modelObjects[i];
        m_modelObjects.clear();
    } else {
        m_listModel->clear();
    }

    emitItemsRemoved(0, cleared);
}

/*!
    \qmlmethod QtQuick2::ListModel::remove(int index, int count = 1)

    Deletes the content at \a index from the model.

    \sa clear()
*/
void QQuickListModel::remove(QQmlV8Function *args)
{
    int argLength = args->Length();

    if (argLength == 1 || argLength == 2) {
        int index = (*args)[0]->Int32Value();
        int removeCount = (argLength == 2 ? ((*args)[1]->Int32Value()) : 1);

        if (index < 0 || index+removeCount > count() || removeCount <= 0) {
            qmlInfo(this) << tr("remove: indices [%1 - %2] out of range [0 - %3]").arg(index).arg(index+removeCount).arg(count());
            return;
        }

        if (m_dynamicRoles) {
            for (int i=0 ; i < removeCount ; ++i)
                delete m_modelObjects[index+i];
            m_modelObjects.remove(index, removeCount);
        } else {
            m_listModel->remove(index, removeCount);
        }

        emitItemsRemoved(index, removeCount);
    } else {
        qmlInfo(this) << tr("remove: incorrect number of arguments");
    }
}

/*!
    \qmlmethod QtQuick2::ListModel::insert(int index, jsobject dict)

    Adds a new item to the list model at position \a index, with the
    values in \a dict.

    \code
        fruitModel.insert(2, {"cost": 5.95, "name":"Pizza"})
    \endcode

    The \a index must be to an existing item in the list, or one past
    the end of the list (equivalent to append).

    \sa set() append()
*/

void QQuickListModel::insert(QQmlV8Function *args)
{
    if (args->Length() == 2) {

        v8::Handle<v8::Value> arg0 = (*args)[0];
        int index = arg0->Int32Value();

        if (index < 0 || index > count()) {
            qmlInfo(this) << tr("insert: index %1 out of range").arg(index);
            return;
        }

        v8::Handle<v8::Value> arg1 = (*args)[1];

        if (arg1->IsArray()) {
            v8::Handle<v8::Array> objectArray = v8::Handle<v8::Array>::Cast(arg1);
            int objectArrayLength = objectArray->Length();
            for (int i=0 ; i < objectArrayLength ; ++i) {
                v8::Handle<v8::Object> argObject = objectArray->Get(i)->ToObject();

                if (m_dynamicRoles) {
                    m_modelObjects.insert(index+i, DynamicRoleModelNode::create(args->engine()->variantMapFromJS(argObject), this));
                } else {
                    m_listModel->insert(index+i, argObject, args->engine());
                }
            }
            emitItemsInserted(index, objectArrayLength);
        } else if (arg1->IsObject()) {
            v8::Handle<v8::Object> argObject = arg1->ToObject();

            if (m_dynamicRoles) {
                m_modelObjects.insert(index, DynamicRoleModelNode::create(args->engine()->variantMapFromJS(argObject), this));
            } else {
                m_listModel->insert(index, argObject, args->engine());
            }

            emitItemsInserted(index, 1);
        } else {
            qmlInfo(this) << tr("insert: value is not an object");
        }
    } else {
        qmlInfo(this) << tr("insert: value is not an object");
    }
}

/*!
    \qmlmethod QtQuick2::ListModel::move(int from, int to, int n)

    Moves \a n items \a from one position \a to another.

    The from and to ranges must exist; for example, to move the first 3 items
    to the end of the list:

    \code
        fruitModel.move(0, fruitModel.count - 3, 3)
    \endcode

    \sa append()
*/
void QQuickListModel::move(int from, int to, int n)
{
    if (n==0 || from==to)
        return;
    if (!canMove(from, to, n)) {
        qmlInfo(this) << tr("move: out of range");
        return;
    }

    if (m_dynamicRoles) {

        int realFrom = from;
        int realTo = to;
        int realN = n;

        if (from > to) {
            // Only move forwards - flip if backwards moving
            int tfrom = from;
            int tto = to;
            realFrom = tto;
            realTo = tto+n;
            realN = tfrom-tto;
        }

        QPODVector<DynamicRoleModelNode *, 4> store;
        for (int i=0 ; i < (realTo-realFrom) ; ++i)
            store.append(m_modelObjects[realFrom+realN+i]);
        for (int i=0 ; i < realN ; ++i)
            store.append(m_modelObjects[realFrom+i]);
        for (int i=0 ; i < store.count() ; ++i)
            m_modelObjects[realFrom+i] = store[i];

    } else {
        m_listModel->move(from, to, n);
    }

    emitItemsMoved(from, to, n);
}

/*!
    \qmlmethod QtQuick2::ListModel::append(jsobject dict)

    Adds a new item to the end of the list model, with the
    values in \a dict.

    \code
        fruitModel.append({"cost": 5.95, "name":"Pizza"})
    \endcode

    \sa set() remove()
*/
void QQuickListModel::append(QQmlV8Function *args)
{
    if (args->Length() == 1) {
        v8::Handle<v8::Value> arg = (*args)[0];

        if (arg->IsArray()) {
            v8::Handle<v8::Array> objectArray = v8::Handle<v8::Array>::Cast(arg);
            int objectArrayLength = objectArray->Length();

            int index = count();
            for (int i=0 ; i < objectArrayLength ; ++i) {
                v8::Handle<v8::Object> argObject = objectArray->Get(i)->ToObject();

                if (m_dynamicRoles) {
                    m_modelObjects.append(DynamicRoleModelNode::create(args->engine()->variantMapFromJS(argObject), this));
                } else {
                    m_listModel->append(argObject, args->engine());
                }
            }

            emitItemsInserted(index, objectArrayLength);
        } else if (arg->IsObject()) {
            v8::Handle<v8::Object> argObject = arg->ToObject();

            int index;

            if (m_dynamicRoles) {
                index = m_modelObjects.count();
                m_modelObjects.append(DynamicRoleModelNode::create(args->engine()->variantMapFromJS(argObject), this));
            } else {
                index = m_listModel->append(argObject, args->engine());
            }

            emitItemsInserted(index, 1);
        } else {
            qmlInfo(this) << tr("append: value is not an object");
        }
    } else {
        qmlInfo(this) << tr("append: value is not an object");
    }
}

/*!
    \qmlmethod object QtQuick2::ListModel::get(int index)

    Returns the item at \a index in the list model. This allows the item
    data to be accessed or modified from JavaScript:

    \code
    Component.onCompleted: {
        fruitModel.append({"cost": 5.95, "name":"Jackfruit"});
        console.log(fruitModel.get(0).cost);
        fruitModel.get(0).cost = 10.95;
    }
    \endcode

    The \a index must be an element in the list.

    Note that properties of the returned object that are themselves objects
    will also be models, and this get() method is used to access elements:

    \code
        fruitModel.append(..., "attributes":
            [{"name":"spikes","value":"7mm"},
             {"name":"color","value":"green"}]);
        fruitModel.get(0).attributes.get(1).value; // == "green"
    \endcode

    \warning The returned object is not guaranteed to remain valid. It
    should not be used in \l{Property Binding}{property bindings}.

    \sa append()
*/
QQmlV8Handle QQuickListModel::get(int index) const
{
    v8::Handle<v8::Value> result = v8::Undefined();

    if (index >= 0 && index < count()) {
        QV8Engine *v8engine = engine();

        if (m_dynamicRoles) {
            DynamicRoleModelNode *object = m_modelObjects[index];
            result = v8engine->newQObject(object);
        } else {
            ModelObject *object = m_listModel->getOrCreateModelObject(const_cast<QQuickListModel *>(this), index);
            result = v8engine->newQObject(object);
        }
    }

    return QQmlV8Handle::fromHandle(result);
}

/*!
    \qmlmethod QtQuick2::ListModel::set(int index, jsobject dict)

    Changes the item at \a index in the list model with the
    values in \a dict. Properties not appearing in \a dict
    are left unchanged.

    \code
        fruitModel.set(3, {"cost": 5.95, "name":"Pizza"})
    \endcode

    If \a index is equal to count() then a new item is appended to the
    list. Otherwise, \a index must be an element in the list.

    \sa append()
*/
void QQuickListModel::set(int index, const QQmlV8Handle &handle)
{
    v8::Handle<v8::Value> valuemap = handle.toHandle();

    if (!valuemap->IsObject() || valuemap->IsArray()) {
        qmlInfo(this) << tr("set: value is not an object");
        return;
    }
    if (index > count() || index < 0) {
        qmlInfo(this) << tr("set: index %1 out of range").arg(index);
        return;
    }

    v8::Handle<v8::Object> object = valuemap->ToObject();

    if (index == count()) {

        if (m_dynamicRoles) {
            m_modelObjects.append(DynamicRoleModelNode::create(engine()->variantMapFromJS(object), this));
        } else {
            m_listModel->insert(index, object, engine());
        }

        emitItemsInserted(index, 1);
    } else {

        QList<int> roles;

        if (m_dynamicRoles) {
            m_modelObjects[index]->updateValues(engine()->variantMapFromJS(object), roles);
        } else {
            m_listModel->set(index, object, &roles, engine());
        }

        if (roles.count())
            emitItemsChanged(index, 1, roles);
    }
}

/*!
    \qmlmethod QtQuick2::ListModel::setProperty(int index, string property, variant value)

    Changes the \a property of the item at \a index in the list model to \a value.

    \code
        fruitModel.setProperty(3, "cost", 5.95)
    \endcode

    The \a index must be an element in the list.

    \sa append()
*/
void QQuickListModel::setProperty(int index, const QString& property, const QVariant& value)
{
    if (count() == 0 || index >= count() || index < 0) {
        qmlInfo(this) << tr("set: index %1 out of range").arg(index);
        return;
    }

    if (m_dynamicRoles) {
        int roleIndex = m_roles.indexOf(property);
        if (roleIndex == -1) {
            roleIndex = m_roles.count();
            m_roles.append(property);
        }
        if (m_modelObjects[index]->setValue(property.toUtf8(), value)) {
            QList<int> roles;
            roles << roleIndex;
            emitItemsChanged(index, 1, roles);
        }
    } else {
        int roleIndex = m_listModel->setOrCreateProperty(index, property, value);
        if (roleIndex != -1) {

            QList<int> roles;
            roles << roleIndex;

            emitItemsChanged(index, 1, roles);
        }
    }
}

/*!
    \qmlmethod QtQuick2::ListModel::sync()

    Writes any unsaved changes to the list model after it has been modified
    from a worker script.
*/
void QQuickListModel::sync()
{
    // This is just a dummy method to make it look like sync() exists in
    // ListModel (and not just QQuickListModelWorkerAgent) and to let
    // us document sync().
    qmlInfo(this) << "List sync() can only be called from a WorkerScript";
}

bool QQuickListModelParser::compileProperty(const QQmlCustomParserProperty &prop, QList<ListInstruction> &instr, QByteArray &data)
{
    QList<QVariant> values = prop.assignedValues();
    for(int ii = 0; ii < values.count(); ++ii) {
        const QVariant &value = values.at(ii);

        if(value.userType() == qMetaTypeId<QQmlCustomParserNode>()) {
            QQmlCustomParserNode node =
                qvariant_cast<QQmlCustomParserNode>(value);

            if (node.name() != listElementTypeName) {
                const QMetaObject *mo = resolveType(node.name());
                if (mo != &QQuickListElement::staticMetaObject) {
                    error(node, QQuickListModel::tr("ListElement: cannot contain nested elements"));
                    return false;
                }
                listElementTypeName = node.name(); // cache right name for next time
            }

            {
            ListInstruction li;
            li.type = ListInstruction::Push;
            li.dataIdx = -1;
            instr << li;
            }

            QList<QQmlCustomParserProperty> props = node.properties();
            for(int jj = 0; jj < props.count(); ++jj) {
                const QQmlCustomParserProperty &nodeProp = props.at(jj);
                if (nodeProp.name().isEmpty()) {
                    error(nodeProp, QQuickListModel::tr("ListElement: cannot contain nested elements"));
                    return false;
                }
                if (nodeProp.name() == QStringLiteral("id")) {
                    error(nodeProp, QQuickListModel::tr("ListElement: cannot use reserved \"id\" property"));
                    return false;
                }

                ListInstruction li;
                int ref = data.count();
                data.append(nodeProp.name().toUtf8());
                data.append('\0');
                li.type = ListInstruction::Set;
                li.dataIdx = ref;
                instr << li;

                if(!compileProperty(nodeProp, instr, data))
                    return false;

                li.type = ListInstruction::Pop;
                li.dataIdx = -1;
                instr << li;
            }

            {
            ListInstruction li;
            li.type = ListInstruction::Pop;
            li.dataIdx = -1;
            instr << li;
            }

        } else {

            QQmlScript::Variant variant =
                qvariant_cast<QQmlScript::Variant>(value);

            int ref = data.count();

            QByteArray d;
            d += char(variant.type()); // type tag
            if (variant.isString()) {
                d += variant.asString().toUtf8();
            } else if (variant.isNumber()) {
                d += QByteArray::number(variant.asNumber(),'g',20);
            } else if (variant.isBoolean()) {
                d += char(variant.asBoolean());
            } else if (variant.isScript()) {
                if (definesEmptyList(variant.asScript())) {
                    d[0] = char(QQmlScript::Variant::Invalid); // marks empty list
                } else {
                    QByteArray script = variant.asScript().toUtf8();
                    int v = evaluateEnum(script);
                    if (v<0) {
                        using namespace QQmlJS;
                        AST::Node *node = variant.asAST();
                        AST::StringLiteral *literal = 0;
                        if (AST::CallExpression *callExpr = AST::cast<AST::CallExpression *>(node)) {
                            if (AST::IdentifierExpression *idExpr = AST::cast<AST::IdentifierExpression *>(callExpr->base)) {
                                if (idExpr->name == QLatin1String("QT_TR_NOOP") || idExpr->name == QLatin1String("QT_TRID_NOOP")) {
                                    if (callExpr->arguments && !callExpr->arguments->next)
                                        literal = AST::cast<AST::StringLiteral *>(callExpr->arguments->expression);
                                    if (!literal) {
                                        error(prop, QQuickListModel::tr("ListElement: improperly specified %1").arg(idExpr->name.toString()));
                                        return false;
                                    }
                                } else if (idExpr->name == QLatin1String("QT_TRANSLATE_NOOP")) {
                                    if (callExpr->arguments && callExpr->arguments->next && !callExpr->arguments->next->next)
                                        literal = AST::cast<AST::StringLiteral *>(callExpr->arguments->next->expression);
                                    if (!literal) {
                                        error(prop, QQuickListModel::tr("ListElement: improperly specified QT_TRANSLATE_NOOP"));
                                        return false;
                                    }
                                }
                            }
                        }

                        if (literal) {
                            d[0] = char(QQmlScript::Variant::String);
                            d += literal->value.toUtf8();
                        } else {
                            error(prop, QQuickListModel::tr("ListElement: cannot use script for property value"));
                            return false;
                        }
                    } else {
                        d[0] = char(QQmlScript::Variant::Number);
                        d += QByteArray::number(v);
                    }
                }
            }
            d.append('\0');
            data.append(d);

            ListInstruction li;
            li.type = ListInstruction::Value;
            li.dataIdx = ref;
            instr << li;
        }
    }

    return true;
}

QByteArray QQuickListModelParser::compile(const QList<QQmlCustomParserProperty> &customProps)
{
    QList<ListInstruction> instr;
    QByteArray data;
    listElementTypeName = QString(); // unknown

    for(int ii = 0; ii < customProps.count(); ++ii) {
        const QQmlCustomParserProperty &prop = customProps.at(ii);
        if(!prop.name().isEmpty()) { // isn't default property
            error(prop, QQuickListModel::tr("ListModel: undefined property '%1'").arg(prop.name()));
            return QByteArray();
        }

        if(!compileProperty(prop, instr, data)) {
            return QByteArray();
        }
    }

    int size = sizeof(ListModelData) +
               instr.count() * sizeof(ListInstruction) +
               data.count();

    QByteArray rv;
    rv.resize(size);

    ListModelData *lmd = (ListModelData *)rv.data();
    lmd->dataOffset = sizeof(ListModelData) +
                     instr.count() * sizeof(ListInstruction);
    lmd->instrCount = instr.count();
    for (int ii = 0; ii < instr.count(); ++ii)
        lmd->instructions()[ii] = instr.at(ii);
    ::memcpy(rv.data() + lmd->dataOffset, data.constData(), data.count());

    return rv;
}

void QQuickListModelParser::setCustomData(QObject *obj, const QByteArray &d)
{
    QQuickListModel *rv = static_cast<QQuickListModel *>(obj);

    QV8Engine *engine = QQmlEnginePrivate::getV8Engine(qmlEngine(rv));
    rv->m_engine = engine;

    const ListModelData *lmd = (const ListModelData *)d.constData();
    const char *data = ((const char *)lmd) + lmd->dataOffset;

    QStack<DataStackElement> stack;

    for (int ii = 0; ii < lmd->instrCount; ++ii) {
        const ListInstruction &instr = lmd->instructions()[ii];

        switch(instr.type) {
        case ListInstruction::Push:
            {
                Q_ASSERT(!rv->m_dynamicRoles);

                ListModel *subModel = 0;

                if (stack.count() == 0) {
                    subModel = rv->m_listModel;
                } else {
                    const DataStackElement &e0 = stack.at(stack.size() - 1);
                    DataStackElement &e1 = stack[stack.size() - 2];

                    const ListLayout::Role &role = e1.model->getOrCreateListRole(e0.name);
                    if (role.type == ListLayout::Role::List) {
                        subModel = e1.model->getListProperty(e1.elementIndex, role);

                        if (subModel == 0) {
                            subModel = new ListModel(role.subLayout, 0, -1);
                            QVariant vModel = QVariant::fromValue(subModel);
                            e1.model->setOrCreateProperty(e1.elementIndex, e0.name, vModel);
                        }
                    }
                }

                DataStackElement e;
                e.model = subModel;
                e.elementIndex = subModel ? subModel->appendElement() : -1;
                stack.push(e);
            }
            break;

        case ListInstruction::Pop:
            stack.pop();
            break;

        case ListInstruction::Value:
            {
                const DataStackElement &e0 = stack.at(stack.size() - 1);
                DataStackElement &e1 = stack[stack.size() - 2];

                QString name = e0.name;
                QVariant value;

                switch (QQmlScript::Variant::Type(data[instr.dataIdx])) {
                    case QQmlScript::Variant::Invalid:
                        {
                            const ListLayout::Role &role = e1.model->getOrCreateListRole(e0.name);
                            ListModel *emptyModel = new ListModel(role.subLayout, 0, -1);
                            value = QVariant::fromValue(emptyModel);
                        }
                        break;
                    case QQmlScript::Variant::Boolean:
                        value = bool(data[1 + instr.dataIdx]);
                        break;
                    case QQmlScript::Variant::Number:
                        value = QByteArray(data + 1 + instr.dataIdx).toDouble();
                        break;
                    case QQmlScript::Variant::String:
                        value = QString::fromUtf8(data + 1 + instr.dataIdx);
                        break;
                    default:
                        Q_ASSERT("Format error in ListInstruction");
                }

                e1.model->setOrCreateProperty(e1.elementIndex, name, value);
            }
            break;

        case ListInstruction::Set:
            {
                DataStackElement e;
                e.name = QString::fromUtf8(data + instr.dataIdx);
                stack.push(e);
            }
            break;
        }
    }
}

bool QQuickListModelParser::definesEmptyList(const QString &s)
{
    if (s.startsWith(QLatin1Char('[')) && s.endsWith(QLatin1Char(']'))) {
        for (int i=1; i<s.length()-1; i++) {
            if (!s[i].isSpace())
                return false;
        }
        return true;
    }
    return false;
}


/*!
    \qmlclass ListElement QQuickListElement
    \inqmlmodule QtQuick 2
    \ingroup qml-working-with-data
    \brief The ListElement element defines a data item in a ListModel.

    List elements are defined inside ListModel definitions, and represent items in a
    list that will be displayed using ListView or \l Repeater items.

    List elements are defined like other QML elements except that they contain
    a collection of \e role definitions instead of properties. Using the same
    syntax as property definitions, roles both define how the data is accessed
    and include the data itself.

    The names used for roles must begin with a lower-case letter and should be
    common to all elements in a given model. Values must be simple constants; either
    strings (quoted and optionally within a call to QT_TR_NOOP), boolean values
    (true, false), numbers, or enumeration values (such as AlignText.AlignHCenter).

    \section1 Referencing Roles

    The role names are used by delegates to obtain data from list elements.
    Each role name is accessible in the delegate's scope, and refers to the
    corresponding role in the current element. Where a role name would be
    ambiguous to use, it can be accessed via the \l{ListView::}{model}
    property (e.g., \c{model.cost} instead of \c{cost}).

    \section1 Example Usage

    The following model defines a series of list elements, each of which
    contain "name" and "cost" roles and their associated values.

    \snippet doc/src/snippets/qml/qml-data-models/listelements.qml model

    The delegate obtains the name and cost for each element by simply referring
    to \c name and \c cost:

    \snippet doc/src/snippets/qml/qml-data-models/listelements.qml view

    \sa ListModel
*/

QT_END_NAMESPACE