qqmlpropertycachecreator_p.h

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QQMLPROPERTYCACHECREATOR_P_H
#define QQMLPROPERTYCACHECREATOR_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include <private/qqmlvaluetype_p.h>
#include <private/qqmlengine_p.h>
#include <private/qqmlmetaobject_p.h>
#include <private/qqmlpropertyresolver_p.h>
#include <private/qqmltypedata_p.h>
#include <private/inlinecomponentutils_p.h>
#include <private/qqmlsourcecoordinate_p.h>
 
#include <QScopedValueRollback>
#include <vector>
 
QT_BEGIN_NAMESPACE
 
inline QQmlError qQmlCompileError(const QV4::CompiledData::Location &location,
                                                  const QString &description)
{
    QQmlError error;
    error.setLine(qmlConvertSourceCoordinate<quint32, int>(location.line()));
    error.setColumn(qmlConvertSourceCoordinate<quint32, int>(location.column()));
    error.setDescription(description);
    return error;
}
 
struct QQmlBindingInstantiationContext {
    QQmlBindingInstantiationContext() {}
    QQmlBindingInstantiationContext(
            int referencingObjectIndex, const QV4::CompiledData::Binding *instantiatingBinding,
            const QString &instantiatingPropertyName,
            const QQmlPropertyCache::ConstPtr &referencingObjectPropertyCache);
 
    bool resolveInstantiatingProperty();
    QQmlPropertyCache::ConstPtr instantiatingPropertyCache() const;
 
    int referencingObjectIndex = -1;
    const QV4::CompiledData::Binding *instantiatingBinding = nullptr;
    QString instantiatingPropertyName;
    QQmlPropertyCache::ConstPtr referencingObjectPropertyCache;
    const QQmlPropertyData *instantiatingProperty = nullptr;
};
 
struct QQmlPendingGroupPropertyBindings : public QVector<QQmlBindingInstantiationContext>
{
    void resolveMissingPropertyCaches(
            QQmlPropertyCacheVector *propertyCaches) const;
};
 
struct QQmlPropertyCacheCreatorBase
{
    Q_DECLARE_TR_FUNCTIONS(QQmlPropertyCacheCreatorBase)
public:
    static QAtomicInt Q_AUTOTEST_EXPORT classIndexCounter;
 
    static QMetaType metaTypeForPropertyType(QV4::CompiledData::CommonType type);
    static QMetaType listTypeForPropertyType(QV4::CompiledData::CommonType type);
 
    static bool canCreateClassNameTypeByUrl(const QUrl &url);
    static QByteArray createClassNameTypeByUrl(const QUrl &url);
 
    static QByteArray createClassNameForInlineComponent(const QUrl &baseUrl, const QString &name);
 
    struct IncrementalResult {
        // valid if and only if an error occurred
        QQmlError error;
        // true if there was no error and there are still components left to process
        bool canResume = false;
        // the object index of the last processed (inline) component root.
        int processedRoot = 0;
    };
};
 
template <typename ObjectContainer>
class QQmlPropertyCacheCreator : public QQmlPropertyCacheCreatorBase
{
public:
    using CompiledObject = typename ObjectContainer::CompiledObject;
    using InlineComponent = typename std::remove_reference<decltype (*(std::declval<CompiledObject>().inlineComponentsBegin()))>::type;
 
    QQmlPropertyCacheCreator(QQmlPropertyCacheVector *propertyCaches,
                             QQmlPendingGroupPropertyBindings *pendingGroupPropertyBindings,
                             QQmlEnginePrivate *enginePrivate,
                             const ObjectContainer *objectContainer, const QQmlImports *imports,
                             const QByteArray &typeClassName);
    ~QQmlPropertyCacheCreator() { propertyCaches->seal(); }
 
 
    IncrementalResult buildMetaObjectsIncrementally();
 
    QQmlError verifyNoICCycle();
 
    enum class VMEMetaObjectIsRequired {
        Maybe,
        Always
    };
protected:
    QQmlError buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context, VMEMetaObjectIsRequired isVMERequired);
    QQmlPropertyCache::ConstPtr propertyCacheForObject(const CompiledObject *obj, const QQmlBindingInstantiationContext &context, QQmlError *error) const;
    QQmlError createMetaObject(int objectIndex, const CompiledObject *obj, const QQmlPropertyCache::ConstPtr &baseTypeCache);
 
    QMetaType metaTypeForParameter(const QV4::CompiledData::ParameterType &param, QString *customTypeName = nullptr);
 
    QString stringAt(int index) const { return objectContainer->stringAt(index); }
 
    QQmlEnginePrivate * const enginePrivate;
    const ObjectContainer * const objectContainer;
    const QQmlImports * const imports;
    QQmlPropertyCacheVector *propertyCaches;
    QQmlPendingGroupPropertyBindings *pendingGroupPropertyBindings;
    QByteArray typeClassName; // not const as we temporarily chang it for inline components
    unsigned int currentRoot; // set to objectID of inline component root when handling inline components
 
    QQmlBindingInstantiationContext m_context;
    std::vector<InlineComponent> allICs;
    std::vector<icutils::Node> nodesSorted;
    std::vector<icutils::Node>::reverse_iterator nodeIt = nodesSorted.rbegin();
    bool hasCycle = false;
};
 
template <typename ObjectContainer>
inline QQmlPropertyCacheCreator<ObjectContainer>::QQmlPropertyCacheCreator(QQmlPropertyCacheVector *propertyCaches,
                                                                           QQmlPendingGroupPropertyBindings *pendingGroupPropertyBindings,
                                                                           QQmlEnginePrivate *enginePrivate,
                                                                           const ObjectContainer *objectContainer, const QQmlImports *imports,
                                                                           const QByteArray &typeClassName)
    : enginePrivate(enginePrivate)
    , objectContainer(objectContainer)
    , imports(imports)
    , propertyCaches(propertyCaches)
    , pendingGroupPropertyBindings(pendingGroupPropertyBindings)
    , typeClassName(typeClassName)
    , currentRoot(-1)
{
    propertyCaches->resetAndResize(objectContainer->objectCount());
 
    using namespace icutils;
 
    // get a list of all inline components
 
    for (int i=0; i != objectContainer->objectCount(); ++i) {
        const CompiledObject *obj = objectContainer->objectAt(i);
        for (auto it = obj->inlineComponentsBegin(); it != obj->inlineComponentsEnd(); ++it) {
            allICs.push_back(*it);
        }
    }
 
    // create a graph on inline components referencing inline components
    std::vector<icutils::Node> nodes;
    nodes.resize(allICs.size());
    std::iota(nodes.begin(), nodes.end(), 0);
    AdjacencyList adjacencyList;
    adjacencyList.resize(nodes.size());
    fillAdjacencyListForInlineComponents(objectContainer, adjacencyList, nodes, allICs);
 
    nodesSorted = topoSort(nodes, adjacencyList, hasCycle);
    nodeIt = nodesSorted.rbegin();
}
 
template <typename ObjectContainer>
inline QQmlError QQmlPropertyCacheCreator<ObjectContainer>::verifyNoICCycle()
{
    if (hasCycle) {
        QQmlError diag;
        diag.setDescription(QLatin1String("Inline components form a cycle!"));
        return diag;
    }
    return {};
}
 
template <typename ObjectContainer>
inline  QQmlPropertyCacheCreatorBase::IncrementalResult
QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectsIncrementally()
{
    // needs to be checked with verifyNoICCycle before this function is called
    Q_ASSERT(!hasCycle);
 
    // create meta objects for inline components before compiling actual root component
    if (nodeIt != nodesSorted.rend()) {
        const auto &ic = allICs[nodeIt->index()];
        QV4::ResolvedTypeReference *typeRef = objectContainer->resolvedType(ic.nameIndex);
        Q_ASSERT(propertyCaches->at(ic.objectIndex).isNull());
        Q_ASSERT(typeRef->typePropertyCache().isNull()); // not set yet
 
        QByteArray icTypeName { objectContainer->stringAt(ic.nameIndex).toUtf8() };
        QScopedValueRollback<QByteArray> nameChange {typeClassName, icTypeName};
        QScopedValueRollback<unsigned int> rootChange {currentRoot, ic.objectIndex};
        ++nodeIt;
        QQmlError diag = buildMetaObjectRecursively(ic.objectIndex, m_context, VMEMetaObjectIsRequired::Always);
        if (diag.isValid()) {
            return {diag, false, 0};
        }
        typeRef->setTypePropertyCache(propertyCaches->at(ic.objectIndex));
        Q_ASSERT(!typeRef->typePropertyCache().isNull());
        return { QQmlError(), true, int(ic.objectIndex) };
    }
 
    auto diag = buildMetaObjectRecursively(/*root object*/0, m_context, VMEMetaObjectIsRequired::Maybe);
    return {diag, false, 0};
}
 
template <typename ObjectContainer>
inline QQmlError QQmlPropertyCacheCreator<ObjectContainer>::buildMetaObjectRecursively(int objectIndex, const QQmlBindingInstantiationContext &context, VMEMetaObjectIsRequired isVMERequired)
{
    auto isAddressable = [](const QUrl &url) {
        const QString fileName = url.fileName();
        return !fileName.isEmpty() && fileName.front().isUpper();
    };
 
    const CompiledObject *obj = objectContainer->objectAt(objectIndex);
    bool needVMEMetaObject = isVMERequired == VMEMetaObjectIsRequired::Always || obj->propertyCount() != 0 || obj->aliasCount() != 0
            || obj->signalCount() != 0 || obj->functionCount() != 0 || obj->enumCount() != 0
            || ((obj->hasFlag(QV4::CompiledData::Object::IsComponent)
                 || (objectIndex == 0 && isAddressable(objectContainer->url())))
                && !objectContainer->resolvedType(obj->inheritedTypeNameIndex)->isFullyDynamicType());
 
    if (!needVMEMetaObject) {
        auto binding = obj->bindingsBegin();
        auto end = obj->bindingsEnd();
        for ( ; binding != end; ++binding) {
            if (binding->type() == QV4::CompiledData::Binding::Type_Object
                    && (binding->flags() & QV4::CompiledData::Binding::IsOnAssignment)) {
                // If the on assignment is inside a group property, we need to distinguish between QObject based
                // group properties and value type group properties. For the former the base type is derived from
                // the property that references us, for the latter we only need a meta-object on the referencing object
                // because interceptors can't go to the shared value type instances.
                if (context.instantiatingProperty && QQmlMetaType::isValueType(context.instantiatingProperty->propType())) {
                    if (!propertyCaches->needsVMEMetaObject(context.referencingObjectIndex)) {
                        const CompiledObject *obj = objectContainer->objectAt(context.referencingObjectIndex);
                        auto *typeRef = objectContainer->resolvedType(obj->inheritedTypeNameIndex);
                        Q_ASSERT(typeRef);
                        QQmlPropertyCache::ConstPtr baseTypeCache = typeRef->createPropertyCache();
                        QQmlError error = baseTypeCache
                            ? createMetaObject(context.referencingObjectIndex, obj, baseTypeCache)
                            : qQmlCompileError(binding->location, QQmlPropertyCacheCreatorBase::tr(
                                    "Type cannot be used for 'on' assignment"));
                        if (error.isValid())
                            return error;
                    }
                } else {
                    // On assignments are implemented using value interceptors, which require a VME meta object.
                    needVMEMetaObject = true;
                }
                break;
            }
        }
    }
 
    QQmlPropertyCache::ConstPtr baseTypeCache;
    {
        QQmlError error;
        baseTypeCache = propertyCacheForObject(obj, context, &error);
        if (error.isValid())
            return error;
    }
 
    if (baseTypeCache) {
        if (needVMEMetaObject) {
            QQmlError error = createMetaObject(objectIndex, obj, baseTypeCache);
            if (error.isValid())
                return error;
        } else {
            propertyCaches->set(objectIndex, baseTypeCache);
        }
    }
 
    QQmlPropertyCache::ConstPtr thisCache = propertyCaches->at(objectIndex);
    auto binding = obj->bindingsBegin();
    auto end = obj->bindingsEnd();
    for (; binding != end; ++binding) {
        switch (binding->type()) {
        case QV4::CompiledData::Binding::Type_Object:
        case QV4::CompiledData::Binding::Type_GroupProperty:
        case QV4::CompiledData::Binding::Type_AttachedProperty:
            // We can always resolve object, group, and attached properties.
            break;
        default:
            // Everything else is of no interest here.
            continue;
        }
 
        QQmlBindingInstantiationContext context(
                    objectIndex, &(*binding), stringAt(binding->propertyNameIndex), thisCache);
 
        // Binding to group property where we failed to look up the type of the
        // property? Possibly a group property that is an alias that's not resolved yet.
        // Let's attempt to resolve it after we're done with the aliases and fill in the
        // propertyCaches entry then.
        if (!thisCache || !context.resolveInstantiatingProperty())
            pendingGroupPropertyBindings->append(context);
 
        QQmlError error = buildMetaObjectRecursively(
                    binding->value.objectIndex, context, VMEMetaObjectIsRequired::Maybe);
        if (error.isValid())
            return error;
    }
 
    QQmlError noError;
    return noError;
}
 
template <typename ObjectContainer>
inline QQmlPropertyCache::ConstPtr QQmlPropertyCacheCreator<ObjectContainer>::propertyCacheForObject(const CompiledObject *obj, const QQmlBindingInstantiationContext &context, QQmlError *error) const
{
    if (context.instantiatingProperty) {
        return context.instantiatingPropertyCache();
    } else if (obj->inheritedTypeNameIndex != 0) {
        auto *typeRef = objectContainer->resolvedType(obj->inheritedTypeNameIndex);
        Q_ASSERT(typeRef);
 
        if (typeRef->isFullyDynamicType()) {
            if (obj->propertyCount() > 0 || obj->aliasCount() > 0) {
                *error = qQmlCompileError(obj->location, QQmlPropertyCacheCreatorBase::tr("Fully dynamic types cannot declare new properties."));
                return nullptr;
            }
            if (obj->signalCount() > 0) {
                *error = qQmlCompileError(obj->location, QQmlPropertyCacheCreatorBase::tr("Fully dynamic types cannot declare new signals."));
                return nullptr;
            }
            if (obj->functionCount() > 0) {
                *error = qQmlCompileError(obj->location, QQmlPropertyCacheCreatorBase::tr("Fully Dynamic types cannot declare new functions."));
                return nullptr;
            }
        }
 
        if (QQmlPropertyCache::ConstPtr propertyCache = typeRef->createPropertyCache())
            return propertyCache;
        *error = qQmlCompileError(
            obj->location,
            QQmlPropertyCacheCreatorBase::tr("Type '%1' cannot declare new members.")
                .arg(stringAt(obj->inheritedTypeNameIndex)));
        return nullptr;
    } else if (const QV4::CompiledData::Binding *binding = context.instantiatingBinding) {
        if (binding->isAttachedProperty()) {
            auto *typeRef = objectContainer->resolvedType(
                    binding->propertyNameIndex);
            Q_ASSERT(typeRef);
            QQmlType qmltype = typeRef->type();
            if (!qmltype.isValid()) {
                imports->resolveType(stringAt(binding->propertyNameIndex),
                                     &qmltype, nullptr, nullptr, nullptr);
            }
 
            const QMetaObject *attachedMo = qmltype.attachedPropertiesType(enginePrivate);
            if (!attachedMo) {
                *error = qQmlCompileError(binding->location, QQmlPropertyCacheCreatorBase::tr("Non-existent attached object"));
                return nullptr;
            }
            return QQmlMetaType::propertyCache(attachedMo);
        } else if (binding->isGroupProperty()) {
            const auto *obj = objectContainer->objectAt(binding->value.objectIndex);
            if (!stringAt(obj->inheritedTypeNameIndex).isEmpty())
                return nullptr;
 
            for (int i = 0, end = objectContainer->objectCount(); i != end; ++i) {
                const auto *ext = objectContainer->objectAt(i);
                if (ext->idNameIndex != binding->propertyNameIndex)
                    continue;
 
                if (ext->inheritedTypeNameIndex == 0)
                    return nullptr;
 
                QQmlBindingInstantiationContext pendingContext(i, &(*binding), QString(), nullptr);
                pendingGroupPropertyBindings->append(pendingContext);
                return nullptr;
            }
        }
    }
    return nullptr;
}
 
template <typename ObjectContainer>
inline QQmlError QQmlPropertyCacheCreator<ObjectContainer>::createMetaObject(
        int objectIndex, const CompiledObject *obj,
        const QQmlPropertyCache::ConstPtr &baseTypeCache)
{
    QQmlPropertyCache::Ptr cache = baseTypeCache->copyAndReserve(
            obj->propertyCount() + obj->aliasCount(),
            obj->functionCount() + obj->propertyCount() + obj->aliasCount() + obj->signalCount(),
            obj->signalCount() + obj->propertyCount() + obj->aliasCount(),
            obj->enumCount());
 
    propertyCaches->setOwn(objectIndex, cache);
    propertyCaches->setNeedsVMEMetaObject(objectIndex);
 
    QByteArray newClassName;
 
    if (objectIndex == /*root object*/0 || int(currentRoot) == objectIndex) {
        newClassName = typeClassName;
    }
    if (newClassName.isEmpty()) {
        newClassName = QQmlMetaObject(baseTypeCache).className();
        newClassName.append("_QML_");
        newClassName.append(QByteArray::number(classIndexCounter.fetchAndAddRelaxed(1)));
    }
 
    cache->_dynamicClassName = newClassName;
 
    using ListPropertyAssignBehavior = typename ObjectContainer::ListPropertyAssignBehavior;
    switch (objectContainer->listPropertyAssignBehavior()) {
    case ListPropertyAssignBehavior::ReplaceIfNotDefault:
        cache->_listPropertyAssignBehavior = "ReplaceIfNotDefault";
        break;
    case ListPropertyAssignBehavior::Replace:
        cache->_listPropertyAssignBehavior = "Replace";
        break;
    case ListPropertyAssignBehavior::Append:
        break;
    }
 
    QQmlPropertyResolver resolver(baseTypeCache);
 
    auto p = obj->propertiesBegin();
    auto pend = obj->propertiesEnd();
    for ( ; p != pend; ++p) {
        bool notInRevision = false;
        const QQmlPropertyData *d = resolver.property(stringAt(p->nameIndex), &notInRevision);
        if (d && d->isFinal())
            return qQmlCompileError(p->location, QQmlPropertyCacheCreatorBase::tr("Cannot override FINAL property"));
    }
 
    auto a = obj->aliasesBegin();
    auto aend = obj->aliasesEnd();
    for ( ; a != aend; ++a) {
        bool notInRevision = false;
        const QQmlPropertyData *d = resolver.property(stringAt(a->nameIndex()), &notInRevision);
        if (d && d->isFinal())
            return qQmlCompileError(a->location, QQmlPropertyCacheCreatorBase::tr("Cannot override FINAL property"));
    }
 
    int effectivePropertyIndex = cache->propertyIndexCacheStart;
    int effectiveMethodIndex = cache->methodIndexCacheStart;
 
    // For property change signal override detection.
    // We prepopulate a set of signal names which already exist in the object,
    // and throw an error if there is a signal/method defined as an override.
    QSet<QString> seenSignals;
    seenSignals << QStringLiteral("destroyed") << QStringLiteral("parentChanged") << QStringLiteral("objectNameChanged");
    const QQmlPropertyCache *parentCache = cache.data();
    while ((parentCache = parentCache->parent().data())) {
        if (int pSigCount = parentCache->signalCount()) {
            int pSigOffset = parentCache->signalOffset();
            for (int i = pSigOffset; i < pSigCount; ++i) {
                const QQmlPropertyData *currPSig = parentCache->signal(i);
                // XXX TODO: find a better way to get signal name from the property data :-/
                for (QQmlPropertyCache::StringCache::ConstIterator iter = parentCache->stringCache.begin();
                     iter != parentCache->stringCache.end(); ++iter) {
                    if (currPSig == (*iter).second) {
                        seenSignals.insert(iter.key());
                        break;
                    }
                }
            }
        }
    }
 
    // Set up notify signals for properties - first normal, then alias
    p = obj->propertiesBegin();
    pend = obj->propertiesEnd();
    for (  ; p != pend; ++p) {
        auto flags = QQmlPropertyData::defaultSignalFlags();
 
        QString changedSigName = stringAt(p->nameIndex) + QLatin1String("Changed");
        seenSignals.insert(changedSigName);
 
        cache->appendSignal(changedSigName, flags, effectiveMethodIndex++);
    }
 
    a = obj->aliasesBegin();
    aend = obj->aliasesEnd();
    for ( ; a != aend; ++a) {
        auto flags = QQmlPropertyData::defaultSignalFlags();
 
        QString changedSigName = stringAt(a->nameIndex()) + QLatin1String("Changed");
        seenSignals.insert(changedSigName);
 
        cache->appendSignal(changedSigName, flags, effectiveMethodIndex++);
    }
 
    auto e = obj->enumsBegin();
    auto eend = obj->enumsEnd();
    for ( ; e != eend; ++e) {
        const int enumValueCount = e->enumValueCount();
        QVector<QQmlEnumValue> values;
        values.reserve(enumValueCount);
 
        auto enumValue = e->enumValuesBegin();
        auto end = e->enumValuesEnd();
        for ( ; enumValue != end; ++enumValue)
            values.append(QQmlEnumValue(stringAt(enumValue->nameIndex), enumValue->value));
 
        cache->appendEnum(stringAt(e->nameIndex), values);
    }
 
    // Dynamic signals
    auto s = obj->signalsBegin();
    auto send = obj->signalsEnd();
    for ( ; s != send; ++s) {
        const int paramCount = s->parameterCount();
 
        QList<QByteArray> names;
        names.reserve(paramCount);
        QVarLengthArray<QMetaType, 10> paramTypes(paramCount);
 
        if (paramCount) {
 
            int i = 0;
            auto param = s->parametersBegin();
            auto end = s->parametersEnd();
            for ( ; param != end; ++param, ++i) {
                names.append(stringAt(param->nameIndex).toUtf8());
 
                QString customTypeName;
                QMetaType type = metaTypeForParameter(param->type, &customTypeName);
                if (!type.isValid())
                    return qQmlCompileError(s->location, QQmlPropertyCacheCreatorBase::tr("Invalid signal parameter type: %1").arg(customTypeName));
 
                paramTypes[i] = type;
            }
        }
 
        auto flags = QQmlPropertyData::defaultSignalFlags();
        if (paramCount)
            flags.setHasArguments(true);
 
        QString signalName = stringAt(s->nameIndex);
        if (seenSignals.contains(signalName))
            return qQmlCompileError(s->location, QQmlPropertyCacheCreatorBase::tr("Duplicate signal name: invalid override of property change signal or superclass signal"));
        seenSignals.insert(signalName);
 
        cache->appendSignal(signalName, flags, effectiveMethodIndex++,
                            paramCount?paramTypes.constData():nullptr, names);
    }
 
 
    // Dynamic slots
    auto function = objectContainer->objectFunctionsBegin(obj);
    auto fend = objectContainer->objectFunctionsEnd(obj);
    for ( ; function != fend; ++function) {
        auto flags = QQmlPropertyData::defaultSlotFlags();
 
        const QString slotName = stringAt(function->nameIndex);
        if (seenSignals.contains(slotName))
            return qQmlCompileError(function->location, QQmlPropertyCacheCreatorBase::tr("Duplicate method name: invalid override of property change signal or superclass signal"));
        // Note: we don't append slotName to the seenSignals list, since we don't
        // protect against overriding change signals or methods with properties.
 
        QList<QByteArray> parameterNames;
        QVector<QMetaType> parameterTypes;
        auto formal = function->formalsBegin();
        auto end = function->formalsEnd();
        for ( ; formal != end; ++formal) {
            flags.setHasArguments(true);
            parameterNames << stringAt(formal->nameIndex).toUtf8();
            QMetaType type = metaTypeForParameter(formal->type);
            if (!type.isValid())
                type = QMetaType::fromType<QVariant>();
            parameterTypes << type;
        }
 
        QMetaType returnType = metaTypeForParameter(function->returnType);
        if (!returnType.isValid())
            returnType = QMetaType::fromType<QVariant>();
 
        cache->appendMethod(slotName, flags, effectiveMethodIndex++, returnType, parameterNames, parameterTypes);
    }
 
 
    // Dynamic properties
    int effectiveSignalIndex = cache->signalHandlerIndexCacheStart;
    int propertyIdx = 0;
    p = obj->propertiesBegin();
    pend = obj->propertiesEnd();
    for ( ; p != pend; ++p, ++propertyIdx) {
        QMetaType propertyType;
        QTypeRevision propertyTypeVersion = QTypeRevision::zero();
        QQmlPropertyData::Flags propertyFlags;
 
        const QV4::CompiledData::CommonType type = p->commonType();
 
        if (p->isList())
            propertyFlags.type = QQmlPropertyData::Flags::QListType;
        else if (type == QV4::CompiledData::CommonType::Var)
            propertyFlags.type = QQmlPropertyData::Flags::VarPropertyType;
 
        if (type != QV4::CompiledData::CommonType::Invalid) {
            propertyType = p->isList()
                    ? listTypeForPropertyType(type)
                    : metaTypeForPropertyType(type);
        } else {
            Q_ASSERT(!p->isCommonType());
 
            QQmlType qmltype;
            bool selfReference = false;
            if (!imports->resolveType(
                    stringAt(p->commonTypeOrTypeNameIndex()), &qmltype, nullptr, nullptr,
                    nullptr, QQmlType::AnyRegistrationType, &selfReference)) {
                return qQmlCompileError(p->location, QQmlPropertyCacheCreatorBase::tr("Invalid property type"));
            }
 
            // inline components are not necessarily valid yet
            Q_ASSERT(qmltype.isValid() || qmltype.isInlineComponentType());
            if (qmltype.isComposite() || qmltype.isInlineComponentType()) {
                QQmlType compositeType;
                if (qmltype.isInlineComponentType()) {
                    const QString icName = qmltype.elementName();
                    compositeType = QQmlMetaType::inlineComponentTypeForUrl(
                            qmltype.sourceUrl(), icName);
                    if (!compositeType.isValid()) // type has not been registered yet, we must be in containing type
                        compositeType = objectContainer->qmlTypeForComponent(icName);
                    Q_ASSERT(compositeType.isValid());
                } else if (selfReference) {
                     compositeType = objectContainer->qmlTypeForComponent();
                } else {
                    QQmlRefPointer<QQmlTypeData> tdata = enginePrivate->typeLoader.getType(qmltype.sourceUrl());
                    Q_ASSERT(tdata);
                    Q_ASSERT(tdata->isComplete());
 
                    auto compilationUnit = tdata->compilationUnit();
                    compositeType = compilationUnit->qmlTypeForComponent();
                }
 
                if (p->isList()) {
                    propertyType = compositeType.qListTypeId();
                } else {
                    propertyType = compositeType.typeId();
                }
            } else {
                if (p->isList())
                    propertyType = qmltype.qListTypeId();
                else
                    propertyType = qmltype.typeId();
                propertyTypeVersion = qmltype.version();
            }
 
            if (p->isList())
                propertyFlags.type = QQmlPropertyData::Flags::QListType;
            else if (propertyType.flags().testFlag(QMetaType::PointerToQObject))
                propertyFlags.type = QQmlPropertyData::Flags::QObjectDerivedType;
            else
                propertyFlags.type = QQmlPropertyData::Flags::ValueType;
        }
 
        if (!p->isReadOnly() && !propertyType.flags().testFlag(QMetaType::IsQmlList))
            propertyFlags.setIsWritable(true);
 
 
        QString propertyName = stringAt(p->nameIndex);
        if (!obj->hasAliasAsDefaultProperty() && propertyIdx == obj->indexOfDefaultPropertyOrAlias)
            cache->_defaultPropertyName = propertyName;
        cache->appendProperty(propertyName, propertyFlags, effectivePropertyIndex++,
                              propertyType, propertyTypeVersion, effectiveSignalIndex);
 
        effectiveSignalIndex++;
    }
 
    QQmlError noError;
    return noError;
}
 
template <typename ObjectContainer>
inline QMetaType QQmlPropertyCacheCreator<ObjectContainer>::metaTypeForParameter(
    const QV4::CompiledData::ParameterType &param, QString *customTypeName)
{
    const quint32 typeId = param.typeNameIndexOrCommonType();
    if (param.indexIsCommonType()) {
        // built-in type
        if (param.isList())
            return listTypeForPropertyType(QV4::CompiledData::CommonType(typeId));
        return metaTypeForPropertyType(QV4::CompiledData::CommonType(typeId));
    }
 
    // lazily resolved type
    const QString typeName = stringAt(param.typeNameIndexOrCommonType());
    if (customTypeName)
        *customTypeName = typeName;
    QQmlType qmltype;
    bool selfReference = false;
    if (!imports->resolveType(typeName, &qmltype, nullptr, nullptr, nullptr,
                              QQmlType::AnyRegistrationType, &selfReference))
        return QMetaType();
 
    if (!qmltype.isComposite()) {
        const QMetaType typeId = param.isList() ? qmltype.qListTypeId() : qmltype.typeId();
        if (!typeId.isValid() && qmltype.isInlineComponentType()) {
            const QQmlType qmlType = objectContainer->qmlTypeForComponent(qmltype.elementName());
            return param.isList() ? qmlType.qListTypeId() : qmlType.typeId();
        } else {
            return typeId;
        }
    }
 
    if (selfReference) {
        const QQmlType qmlType = objectContainer->qmlTypeForComponent();
        return param.isList() ? qmlType.qListTypeId() : qmlType.typeId();
    }
 
    QQmlRefPointer<QQmlTypeData> tdata = enginePrivate->typeLoader.getType(qmltype.sourceUrl());
    Q_ASSERT(tdata);
    Q_ASSERT(tdata->isComplete());
 
    auto compilationUnit = tdata->compilationUnit();
 
    return param.isList()
               ? compilationUnit->qmlType.qListTypeId()
               : compilationUnit->qmlType.typeId();
}
 
template <typename ObjectContainer>
class QQmlPropertyCacheAliasCreator
{
public:
    typedef typename ObjectContainer::CompiledObject CompiledObject;
 
    QQmlPropertyCacheAliasCreator(
            QQmlPropertyCacheVector *propertyCaches, const ObjectContainer *objectContainer);
    QQmlError appendAliasesToPropertyCache(
            const CompiledObject &component, int objectIndex, QQmlEnginePrivate *enginePriv);
 
private:
    QQmlError propertyDataForAlias(
            const CompiledObject &component, const QV4::CompiledData::Alias &alias, QMetaType *type,
            QTypeRevision *version, QQmlPropertyData::Flags *propertyFlags,
            QQmlEnginePrivate *enginePriv);
    int objectForId(const CompiledObject &component, int id) const;
 
    QQmlPropertyCacheVector *propertyCaches;
    const ObjectContainer *objectContainer;
};
 
template <typename ObjectContainer>
inline QQmlPropertyCacheAliasCreator<ObjectContainer>::QQmlPropertyCacheAliasCreator(
        QQmlPropertyCacheVector *propertyCaches, const ObjectContainer *objectContainer)
    : propertyCaches(propertyCaches)
    , objectContainer(objectContainer)
{
}
 
template <typename ObjectContainer>
inline QQmlError QQmlPropertyCacheAliasCreator<ObjectContainer>::propertyDataForAlias(
        const CompiledObject &component, const QV4::CompiledData::Alias &alias, QMetaType *type,
        QTypeRevision *version, QQmlPropertyData::Flags *propertyFlags,
        QQmlEnginePrivate *enginePriv)
{
    *type = QMetaType();
    bool writable = false;
    bool resettable = false;
    bool bindable = false;
 
    propertyFlags->setIsAlias(true);
 
    if (alias.isAliasToLocalAlias()) {
        const QV4::CompiledData::Alias *lastAlias = &alias;
        QVarLengthArray<const QV4::CompiledData::Alias *, 4> seenAliases({lastAlias});
 
        do {
            const int targetObjectIndex = objectForId(component, lastAlias->targetObjectId());
            Q_ASSERT(targetObjectIndex >= 0);
            const CompiledObject *targetObject = objectContainer->objectAt(targetObjectIndex);
            Q_ASSERT(targetObject);
 
            auto nextAlias = targetObject->aliasesBegin();
            for (uint i = 0; i < lastAlias->localAliasIndex; ++i)
                ++nextAlias;
 
            const QV4::CompiledData::Alias *targetAlias = &(*nextAlias);
            if (seenAliases.contains(targetAlias)) {
                return qQmlCompileError(targetAlias->location,
                                        QQmlPropertyCacheCreatorBase::tr("Cyclic alias"));
            }
 
            seenAliases.append(targetAlias);
            lastAlias = targetAlias;
        } while (lastAlias->isAliasToLocalAlias());
 
        return propertyDataForAlias(
                    component, *lastAlias, type, version, propertyFlags, enginePriv);
    }
 
    const int targetObjectIndex = objectForId(component, alias.targetObjectId());
    Q_ASSERT(targetObjectIndex >= 0);
    const CompiledObject &targetObject = *objectContainer->objectAt(targetObjectIndex);
 
    if (alias.encodedMetaPropertyIndex == -1) {
        Q_ASSERT(alias.hasFlag(QV4::CompiledData::Alias::AliasPointsToPointerObject));
        auto *typeRef = objectContainer->resolvedType(targetObject.inheritedTypeNameIndex);
        if (!typeRef) {
            // Can be caused by the alias target not being a valid id or property. E.g.:
            // property alias dataValue: dataVal
            // invalidAliasComponent { id: dataVal }
            return qQmlCompileError(targetObject.location,
                                    QQmlPropertyCacheCreatorBase::tr("Invalid alias target"));
        }
 
        const auto referencedType = typeRef->type();
        if (referencedType.isValid()) {
            *type = referencedType.typeId();
            if (!type->isValid() && referencedType.isInlineComponentType()) {
                *type = objectContainer->qmlTypeForComponent(referencedType.elementName()).typeId();
                Q_ASSERT(type->isValid());
            }
        } else {
            *type = typeRef->compilationUnit()->qmlType.typeId();
        }
 
        *version = typeRef->version();
 
        propertyFlags->type = QQmlPropertyData::Flags::QObjectDerivedType;
    } else {
        int coreIndex = QQmlPropertyIndex::fromEncoded(alias.encodedMetaPropertyIndex).coreIndex();
        int valueTypeIndex = QQmlPropertyIndex::fromEncoded(
                    alias.encodedMetaPropertyIndex).valueTypeIndex();
 
        QQmlPropertyCache::ConstPtr targetCache = propertyCaches->at(targetObjectIndex);
        Q_ASSERT(targetCache);
 
        const QQmlPropertyData *targetProperty = targetCache->property(coreIndex);
        Q_ASSERT(targetProperty);
 
        // for deep aliases, valueTypeIndex is always set
        if (!QQmlMetaType::isValueType(targetProperty->propType()) && valueTypeIndex != -1) {
            // deep alias property
            *type = targetProperty->propType();
            QQmlPropertyCache::ConstPtr typeCache = QQmlMetaType::propertyCacheForType(*type);
            Q_ASSERT(typeCache);
            const QQmlPropertyData *typeProperty = typeCache->property(valueTypeIndex);
 
            if (typeProperty == nullptr) {
                return qQmlCompileError(alias.referenceLocation,
                                        QQmlPropertyCacheCreatorBase::tr("Invalid alias target"));
            }
 
            *type = typeProperty->propType();
            writable = typeProperty->isWritable();
            resettable = typeProperty->isResettable();
            bindable = typeProperty->isBindable();
        } else {
            // value type or primitive type or enum
            *type = targetProperty->propType();
 
            writable = targetProperty->isWritable();
            resettable = targetProperty->isResettable();
            bindable = targetProperty->isBindable();
 
            if (valueTypeIndex != -1) {
                const QMetaObject *valueTypeMetaObject = QQmlMetaType::metaObjectForValueType(*type);
                if (valueTypeMetaObject->property(valueTypeIndex).isEnumType())
                    *type = QMetaType::fromType<int>();
                else
                    *type = valueTypeMetaObject->property(valueTypeIndex).metaType();
            } else {
                if (targetProperty->isEnum()) {
                    *type = QMetaType::fromType<int>();
                } else {
                    // Copy type flags
                    propertyFlags->copyPropertyTypeFlags(targetProperty->flags());
 
                    if (targetProperty->isVarProperty())
                        propertyFlags->type = QQmlPropertyData::Flags::QVariantType;
                }
            }
        }
    }
 
    propertyFlags->setIsWritable(!(alias.hasFlag(QV4::CompiledData::Alias::IsReadOnly))
                                 && writable);
    propertyFlags->setIsResettable(resettable);
    propertyFlags->setIsBindable(bindable);
    return QQmlError();
}
 
template <typename ObjectContainer>
inline QQmlError QQmlPropertyCacheAliasCreator<ObjectContainer>::appendAliasesToPropertyCache(
        const CompiledObject &component, int objectIndex, QQmlEnginePrivate *enginePriv)
{
    const CompiledObject &object = *objectContainer->objectAt(objectIndex);
    if (!object.aliasCount())
        return QQmlError();
 
    QQmlPropertyCache::Ptr propertyCache = propertyCaches->ownAt(objectIndex);
    Q_ASSERT(propertyCache);
 
    int effectiveSignalIndex = propertyCache->signalHandlerIndexCacheStart + propertyCache->propertyIndexCache.size();
    int effectivePropertyIndex = propertyCache->propertyIndexCacheStart + propertyCache->propertyIndexCache.size();
 
    int aliasIndex = 0;
    auto alias = object.aliasesBegin();
    auto end = object.aliasesEnd();
    for ( ; alias != end; ++alias, ++aliasIndex) {
        Q_ASSERT(alias->hasFlag(QV4::CompiledData::Alias::Resolved));
 
        QMetaType type;
        QTypeRevision version = QTypeRevision::zero();
        QQmlPropertyData::Flags propertyFlags;
        QQmlError error = propertyDataForAlias(component, *alias, &type, &version,
                                               &propertyFlags, enginePriv);
        if (error.isValid())
            return error;
 
        const QString propertyName = objectContainer->stringAt(alias->nameIndex());
 
        if (object.hasAliasAsDefaultProperty() && aliasIndex == object.indexOfDefaultPropertyOrAlias)
            propertyCache->_defaultPropertyName = propertyName;
 
        propertyCache->appendProperty(propertyName, propertyFlags, effectivePropertyIndex++,
                                      type, version, effectiveSignalIndex++);
    }
 
    return QQmlError();
}
 
template <typename ObjectContainer>
inline int QQmlPropertyCacheAliasCreator<ObjectContainer>::objectForId(const CompiledObject &component, int id) const
{
    for (quint32 i = 0, count = component.namedObjectsInComponentCount(); i < count; ++i) {
        const int candidateIndex = component.namedObjectsInComponentTable()[i];
        const CompiledObject &candidate = *objectContainer->objectAt(candidateIndex);
        if (candidate.objectId() == id)
            return candidateIndex;
    }
    return -1;
}
 
QT_END_NAMESPACE
 
#endif // QQMLPROPERTYCACHECREATOR_P_H