qt-creator/src/libs/qmljs/qmljsinterpreter.cpp

/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** Commercial Usage
**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
**
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
**
**************************************************************************/

#include "qmljsinterpreter.h"

#include <QtCore/QMetaObject>
#include <QtCore/QMetaProperty>
#include <QtCore/QDebug>

#ifndef NO_DECLARATIVE_BACKEND
#  include <QtDeclarative/QmlType>
#  include <QtDeclarative/QmlMetaType>
#  include <QtDeclarative/private/qmlgraphicsanchors_p.h> // ### remove me
#  include <QtDeclarative/private/qmlgraphicsrectangle_p.h> // ### remove me
#  include <QtDeclarative/private/qmlvaluetype_p.h> // ### remove me
#endif

using namespace QmlJS::Interpreter;

namespace {

#ifndef NO_DECLARATIVE_BACKEND

class QmlAttachedKeys: public ObjectValue
{
    static const char **builtinPropertyNames()
    {
        static const char *properties[] = {
            "enabledChanged",
            "pressed",
            "released",
            "digit0Pressed",
            "digit1Pressed",
            "digit2Pressed",
            "digit3Pressed",
            "digit4Pressed",
            "digit5Pressed",
            "digit6Pressed",
            "digit7Pressed",
            "digit8Pressed",
            "digit9Pressed",
            "leftPressed",
            "rightPressed",
            "upPressed",
            "downPressed",
            "asteriskPressed",
            "numberSignPressed",
            "escapePressed",
            "returnPressed",
            "enterPressed",
            "deletePressed",
            "spacePressed",
            "backPressed",
            "cancelPressed",
            "selectPressed",
            "yesPressed",
            "noPressed",
            "context1Pressed",
            "context2Pressed",
            "context3Pressed",
            "context4Pressed",
            "callPressed",
            "hangupPressed",
            "flipPressed",
            "menuPressed",
            "volumeUpPressed",
            "volumeDownPressed",
            0
        };

        return properties;
    }

    QSet<QString> _generatedSlots;

public:
    QmlAttachedKeys(Engine *engine)
        : ObjectValue(engine)
    {
        for (const char **it = builtinPropertyNames(); *it; ++it) {
            QString signalName = QLatin1String(*it);
            QString generatedSlot = QLatin1String("on");
            generatedSlot += signalName.at(0).toUpper();
            generatedSlot += signalName.midRef(1);
            _generatedSlots.insert(generatedSlot);
        }
    }

    virtual void processMembers(MemberProcessor *processor) const
    {
        foreach (const QString &generatedSlot, _generatedSlots)
            processor->processSlot(generatedSlot, engine()->undefinedValue());

        ObjectValue::processMembers(processor);
    }
};

class MetaFunction: public FunctionValue
{
    QMetaMethod _method;

public:
    MetaFunction(const QMetaMethod &method, Engine *engine)
        : FunctionValue(engine), _method(method)
    {
        engine->registerObject(this);
    }

    virtual const Value *returnValue() const
    {
        return engine()->undefinedValue();
    }

    virtual int argumentCount() const
    {
        return _method.parameterNames().size();
    }

    virtual const Value *argument(int) const
    {
        return engine()->undefinedValue();
    }

    virtual QString argumentName(int index) const
    {
        if (index < _method.parameterNames().size())
            return _method.parameterNames().at(index);

        return FunctionValue::argumentName(index);
    }

    virtual bool isVariadic() const
    {
        return false;
    }

    virtual const Value *invoke(const Activation *) const
    {
        return engine()->undefinedValue();
    }
};

class QmlObjectValue: public ObjectValue
{
public:
    QmlObjectValue(const QMetaObject *metaObject, Engine *engine)
        : ObjectValue(engine), _metaObject(metaObject)
    {
    }

    virtual ~QmlObjectValue() {}

    virtual const Value *lookupMember(const QString &name) const
    {
        for (int index = 0; index < _metaObject->propertyCount(); ++index) {
            QMetaProperty prop = _metaObject->property(index);

            if (name == QString::fromUtf8(prop.name()))
                return propertyValue(prop);
        }

        for (int index = 0; index < _metaObject->methodCount(); ++index) {
            QMetaMethod method = _metaObject->method(index);

            const QString signature = QString::fromUtf8(method.signature());

            const int indexOfParen = signature.indexOf(QLatin1Char('('));
            if (indexOfParen == -1)
                continue; // skip it, invalid signature.

            const QString methodName = signature.left(indexOfParen);

            if (methodName != name) {
                continue;

            } else if (method.methodType() == QMetaMethod::Slot && method.access() == QMetaMethod::Public) {
                return new MetaFunction(method, engine());

            } else if (method.methodType() == QMetaMethod::Signal && method.access() != QMetaMethod::Private) {
                return new MetaFunction(method, engine());
            }
        }

        return ObjectValue::lookupMember(name);
    }

    virtual void processMembers(MemberProcessor *processor) const
    {
        for (int index = 0; index < _metaObject->propertyCount(); ++index) {
            QMetaProperty prop = _metaObject->property(index);

            processor->processProperty(prop.name(), propertyValue(prop));
        }

        for (int index = 0; index < _metaObject->methodCount(); ++index) {
            QMetaMethod method = _metaObject->method(index);

            const QString signature = QString::fromUtf8(method.signature());

            const int indexOfParen = signature.indexOf(QLatin1Char('('));
            if (indexOfParen == -1)
                continue; // skip it, invalid signature.

            const QString methodName = signature.left(indexOfParen);

            if (method.methodType() == QMetaMethod::Slot && method.access() == QMetaMethod::Public) {
                processor->processSlot(methodName, engine()->undefinedValue());

            } else if (method.methodType() == QMetaMethod::Signal && method.access() != QMetaMethod::Private) {
                // process the signal
                processor->processSignal(methodName, engine()->undefinedValue());

                QString slotName;
                slotName += QLatin1String("on");
                slotName += methodName.at(0).toUpper();
                slotName += methodName.midRef(1);

                // process the generated slot
                processor->processGeneratedSlot(slotName, engine()->undefinedValue());
            }
        }

        ObjectValue::processMembers(processor);
    }

    const Value *propertyValue(const QMetaProperty &prop) const {
        const Value *value = engine()->undefinedValue();

        if (QmlMetaType::isObject(prop.userType())) {
            QString typeName = QString::fromUtf8(prop.typeName());

            if (typeName.endsWith(QLatin1Char('*')))
                typeName.truncate(typeName.length() - 1);

            typeName.replace(QLatin1Char('.'), QLatin1Char('/'));

            if (const ObjectValue *objectValue = engine()->newQmlObject(typeName))
                return objectValue;
        }

        switch (prop.type()) {
        case QMetaType::QByteArray:
        case QMetaType::QString:
        case QMetaType::QUrl:
            value = engine()->stringValue();
            break;

        case QMetaType::Bool:
            value = engine()->booleanValue();
            break;

        case QMetaType::Int:
        case QMetaType::Float:
        case QMetaType::Double:
            value = engine()->numberValue();
            break;

        case QMetaType::QFont: {
            // ### cache
            ObjectValue *object = engine()->newObject(/*prototype =*/ 0);
            object->setProperty("family", engine()->stringValue());
            object->setProperty("weight", engine()->undefinedValue()); // ### make me an object
            object->setProperty("copitalization", engine()->undefinedValue()); // ### make me an object
            object->setProperty("bold", engine()->booleanValue());
            object->setProperty("italic", engine()->booleanValue());
            object->setProperty("underline", engine()->booleanValue());
            object->setProperty("overline", engine()->booleanValue());
            object->setProperty("strikeout", engine()->booleanValue());
            object->setProperty("pointSize", engine()->numberValue());
            object->setProperty("pixelSize", engine()->numberValue());
            object->setProperty("letterSpacing", engine()->numberValue());
            object->setProperty("wordSpacing", engine()->numberValue());
            value = object;
        } break;

        case QMetaType::QPoint:
        case QMetaType::QPointF: {
            // ### cache
            ObjectValue *object = engine()->newObject(/*prototype =*/ 0);
            object->setProperty("x", engine()->numberValue());
            object->setProperty("y", engine()->numberValue());
            value = object;
        } break;

        case QMetaType::QRect:
        case QMetaType::QRectF: {
            // ### cache
            ObjectValue *object = engine()->newObject(/*prototype =*/ 0);
            object->setProperty("x", engine()->numberValue());
            object->setProperty("y", engine()->numberValue());
            object->setProperty("width", engine()->numberValue());
            object->setProperty("height", engine()->numberValue());
            value = object;
        } break;

        default:
            break;
        } // end of switch

        return value;
    }

private:
    const QMetaObject *_metaObject;
};

#endif

////////////////////////////////////////////////////////////////////////////////
// constructors
////////////////////////////////////////////////////////////////////////////////
class ObjectCtor: public Function
{
public:
    ObjectCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class FunctionCtor: public Function
{
public:
    FunctionCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class ArrayCtor: public Function
{
public:
    ArrayCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class StringCtor: public Function
{
public:
    StringCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class BooleanCtor: public Function
{
public:
    BooleanCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class NumberCtor: public Function
{
public:
    NumberCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class DateCtor: public Function
{
public:
    DateCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

class RegExpCtor: public Function
{
public:
    RegExpCtor(Engine *engine);

    virtual const Value *invoke(const Activation *activation) const;
};

ObjectCtor::ObjectCtor(Engine *engine)
    : Function(engine)
{
}

FunctionCtor::FunctionCtor(Engine *engine)
    : Function(engine)
{
}

ArrayCtor::ArrayCtor(Engine *engine)
    : Function(engine)
{
}

StringCtor::StringCtor(Engine *engine)
    : Function(engine)
{
}

BooleanCtor::BooleanCtor(Engine *engine)
    : Function(engine)
{
}

NumberCtor::NumberCtor(Engine *engine)
    : Function(engine)
{
}

DateCtor::DateCtor(Engine *engine)
    : Function(engine)
{
}

RegExpCtor::RegExpCtor(Engine *engine)
    : Function(engine)
{
}

const Value *ObjectCtor::invoke(const Activation *activation) const
{
    ObjectValue *thisObject = activation->thisObject();
    if (activation->calledAsFunction())
        thisObject = engine()->newObject();

    thisObject->setClassName("Object");
    thisObject->setPrototype(engine()->objectPrototype());
    thisObject->setProperty("length", engine()->numberValue());
    return thisObject;
}

const Value *FunctionCtor::invoke(const Activation *activation) const
{
    ObjectValue *thisObject = activation->thisObject();
    if (activation->calledAsFunction())
        thisObject = engine()->newObject();

    thisObject->setClassName("Function");
    thisObject->setPrototype(engine()->functionPrototype());
    thisObject->setProperty("length", engine()->numberValue());
    return thisObject;
}

const Value *ArrayCtor::invoke(const Activation *activation) const
{
    ObjectValue *thisObject = activation->thisObject();
    if (activation->calledAsFunction())
        thisObject = engine()->newObject();

    thisObject->setClassName("Array");
    thisObject->setPrototype(engine()->arrayPrototype());
    thisObject->setProperty("length", engine()->numberValue());
    return thisObject;
}

const Value *StringCtor::invoke(const Activation *activation) const
{
    if (activation->calledAsFunction())
        return engine()->convertToString(activation->thisObject());

    ObjectValue *thisObject = activation->thisObject();
    thisObject->setClassName("String");
    thisObject->setPrototype(engine()->stringPrototype());
    thisObject->setProperty("length", engine()->numberValue());
    return thisObject;
}

const Value *BooleanCtor::invoke(const Activation *activation) const
{
    if (activation->calledAsFunction())
        return engine()->convertToBoolean(activation->thisObject());

    ObjectValue *thisObject = activation->thisObject();
    thisObject->setClassName("Boolean");
    thisObject->setPrototype(engine()->booleanPrototype());
    return thisObject;
}

const Value *NumberCtor::invoke(const Activation *activation) const
{
    if (activation->calledAsFunction())
        return engine()->convertToNumber(activation->thisObject());

    ObjectValue *thisObject = activation->thisObject();
    thisObject->setClassName("Number");
    thisObject->setPrototype(engine()->numberPrototype());
    return thisObject;
}

const Value *DateCtor::invoke(const Activation *activation) const
{
    if (activation->calledAsFunction())
        return engine()->stringValue();

    ObjectValue *thisObject = activation->thisObject();
    thisObject->setClassName("Date");
    thisObject->setPrototype(engine()->datePrototype());
    return thisObject;
}

const Value *RegExpCtor::invoke(const Activation *activation) const
{
    ObjectValue *thisObject = activation->thisObject();
    if (activation->calledAsFunction())
        thisObject = engine()->newObject();

    thisObject->setClassName("RegExp");
    thisObject->setPrototype(engine()->regexpPrototype());
    thisObject->setProperty("source", engine()->stringValue());
    thisObject->setProperty("global", engine()->booleanValue());
    thisObject->setProperty("ignoreCase", engine()->booleanValue());
    thisObject->setProperty("multiline", engine()->booleanValue());
    thisObject->setProperty("lastIndex", engine()->numberValue());
    return thisObject;
}

} // end of anonymous namespace

////////////////////////////////////////////////////////////////////////////////
// ValueVisitor
////////////////////////////////////////////////////////////////////////////////
ValueVisitor::ValueVisitor()
{
}

ValueVisitor::~ValueVisitor()
{
}

void ValueVisitor::visit(const NullValue *)
{
}

void ValueVisitor::visit(const UndefinedValue *)
{
}

void ValueVisitor::visit(const NumberValue *)
{
}

void ValueVisitor::visit(const BooleanValue *)
{
}

void ValueVisitor::visit(const StringValue *)
{
}

void ValueVisitor::visit(const ObjectValue *)
{
}

void ValueVisitor::visit(const FunctionValue *)
{
}


////////////////////////////////////////////////////////////////////////////////
// Value
////////////////////////////////////////////////////////////////////////////////
Value::Value()
{
}

Value::~Value()
{
}

const NullValue *Value::asNullValue() const
{
    return 0;
}

const UndefinedValue *Value::asUndefinedValue() const
{
    return 0;
}

const NumberValue *Value::asNumberValue() const
{
    return 0;
}

const BooleanValue *Value::asBooleanValue() const
{
    return 0;
}

const StringValue *Value::asStringValue() const
{
    return 0;
}

const ObjectValue *Value::asObjectValue() const
{
    return 0;
}

const FunctionValue *Value::asFunctionValue() const
{
    return 0;
}

////////////////////////////////////////////////////////////////////////////////
// Environment
////////////////////////////////////////////////////////////////////////////////
Environment::Environment()
{
}

Environment::~Environment()
{
}

const Environment *Environment::parent() const
{
    return 0;
}

const Value *Environment::lookup(const QString &name) const
{
    if (const Value *member = lookupMember(name))
        return member;

    else if (const Environment *p = parent())
        return p->lookup(name);

    else
        return 0;
}

const Value *Environment::lookupMember(const QString &name) const {
    Q_UNUSED(name);
    return 0;
}

////////////////////////////////////////////////////////////////////////////////
// Values
////////////////////////////////////////////////////////////////////////////////
const NullValue *NullValue::asNullValue() const
{
    return this;
}

void NullValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

const UndefinedValue *UndefinedValue::asUndefinedValue() const
{
    return this;
}

void UndefinedValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

const NumberValue *NumberValue::asNumberValue() const
{
    return this;
}

void NumberValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

const BooleanValue *BooleanValue::asBooleanValue() const
{
    return this;
}

void BooleanValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

const StringValue *StringValue::asStringValue() const
{
    return this;
}

void StringValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

MemberProcessor::MemberProcessor()
{
}

MemberProcessor::~MemberProcessor()
{
}

bool MemberProcessor::processProperty(const QString &, const Value *)
{
    return true;
}

bool MemberProcessor::processSignal(const QString &, const Value *)
{
    return true;
}

bool MemberProcessor::processSlot(const QString &, const Value *)
{
    return true;
}

bool MemberProcessor::processGeneratedSlot(const QString &, const Value *)
{
    return true;
}

ObjectValue::ObjectValue(Engine *engine)
    : _engine(engine), _prototype(0), _scope(0)
{
}

ObjectValue::~ObjectValue()
{
}

Engine *ObjectValue::engine() const
{
    return _engine;
}

QString ObjectValue::className() const
{
    return _className;
}

void ObjectValue::setClassName(const QString &className)
{
    _className = className;
}

const ObjectValue *ObjectValue::prototype() const
{
    return _prototype;
}

const ObjectValue *ObjectValue::scope() const
{
    return _scope;
}

void ObjectValue::setScope(const ObjectValue *scope)
{
    _scope = scope;
}

void ObjectValue::setProperty(const QString &name, const Value *value)
{
    _members[name] = value;
}

void ObjectValue::removeProperty(const QString &name)
{
    _members.remove(name);
}

const ObjectValue *ObjectValue::asObjectValue() const
{
    return this;
}

void ObjectValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

const Value *ObjectValue::property(const QString &name) const
{
    return lookupMember(name);
}

void ObjectValue::setPrototype(const ObjectValue *prototype)
{
    QSet<const ObjectValue *> processed;

    if (! prototype || checkPrototype(prototype, &processed))
        _prototype = prototype;
    else
        qWarning() << "**** invalid prototype:";
}

bool ObjectValue::checkPrototype(const ObjectValue *proto, QSet<const ObjectValue *> *processed) const
{
    const int previousSize = processed->size();
    processed->insert(this);

    if (previousSize != processed->size()) {
        if (this == proto)
            return false;

        if (prototype() && ! prototype()->checkPrototype(proto, processed))
            return false;

        return true;
    }

    return false;
}

void ObjectValue::processMembers(MemberProcessor *processor) const
{
    QHashIterator<QString, const Value *> it(_members);

    while (it.hasNext()) {
        it.next();

        if (! processor->processProperty(it.key(), it.value()))
            break;
    }
}

const Environment *ObjectValue::parent() const
{
    return _scope;
}

const Value *ObjectValue::lookupMember(const QString &name) const
{
    if (const Value *m = _members.value(name))
        return m;

    if (_prototype) {
        if (const Value *m = _prototype->lookup(name))
            return m;
    }

    return 0;
}

Activation::Activation(Engine *engine)
    : ObjectValue(engine),
      _thisObject(0),
      _calledAsFunction(true)
{
}

Activation::~Activation()
{
}

bool Activation::calledAsConstructor() const
{
    return ! _calledAsFunction;
}

void Activation::setCalledAsConstructor(bool calledAsConstructor)
{
    _calledAsFunction = ! calledAsConstructor;
}

bool Activation::calledAsFunction() const
{
    return _calledAsFunction;
}

void Activation::setCalledAsFunction(bool calledAsFunction)
{
    _calledAsFunction = calledAsFunction;
}

ObjectValue *Activation::thisObject() const
{
    return _thisObject;
}

void Activation::setThisObject(ObjectValue *thisObject)
{
    _thisObject = thisObject;
}

ValueList Activation::arguments() const
{
    return _arguments;
}

void Activation::setArguments(const ValueList &arguments)
{
    _arguments = arguments;
}

FunctionValue::FunctionValue(Engine *engine)
    : ObjectValue(engine)
{
}

FunctionValue::~FunctionValue()
{
}

const Value *FunctionValue::construct(const ValueList &actuals) const
{
    Activation activation(engine()); // ### FIXME: create on the heap
    activation.setCalledAsConstructor(true);
    activation.setThisObject(engine()->newObject());
    activation.setArguments(actuals);
    return invoke(&activation);
}

const Value *FunctionValue::call(const ValueList &actuals) const
{
    Activation activation(engine()); // ### FIXME: create on the heap
    activation.setCalledAsFunction(true);
    activation.setThisObject(engine()->globalObject()); // ### FIXME: it should be `null'
    activation.setArguments(actuals);
    return invoke(&activation);
}

const Value *FunctionValue::call(const ObjectValue *thisObject, const ValueList &actuals) const
{
    Activation activation(engine()); // ### FIXME: create on the heap
    activation.setCalledAsFunction(true);
    activation.setThisObject(const_cast<ObjectValue *>(thisObject)); // ### FIXME: remove the const_cast
    activation.setArguments(actuals);
    return invoke(&activation);
}

const Value *FunctionValue::returnValue() const
{
    return engine()->undefinedValue();
}

int FunctionValue::argumentCount() const
{
    return 0;
}

const Value *FunctionValue::argument(int) const
{
    return engine()->undefinedValue();
}

QString FunctionValue::argumentName(int index) const
{
    return QString::fromLatin1("arg%1").arg(index);
}

bool FunctionValue::isVariadic() const
{
    return true;
}

const Value *FunctionValue::invoke(const Activation *activation) const
{
    return activation->thisObject(); // ### FIXME: it should return undefined
}

const FunctionValue *FunctionValue::asFunctionValue() const
{
    return this;
}

void FunctionValue::accept(ValueVisitor *visitor) const
{
    visitor->visit(this);
}

Function::Function(Engine *engine)
    : FunctionValue(engine), _returnValue(0)
{
    setClassName("Function");
}

Function::~Function()
{
}

void Function::addArgument(const Value *argument)
{
    _arguments.push_back(argument);
}

const Value *Function::returnValue() const
{
    return _returnValue;
}

void Function::setReturnValue(const Value *returnValue)
{
    _returnValue = returnValue;
}

int Function::argumentCount() const
{
    return _arguments.size();
}

const Value *Function::argument(int index) const
{
    return _arguments.at(index);
}

const Value *Function::property(const QString &name) const
{
    if (name == "length")
        return engine()->numberValue();

    return FunctionValue::property(name);
}

const Value *Function::invoke(const Activation *activation) const
{
    return activation->thisObject(); // ### FIXME it should return undefined
}

////////////////////////////////////////////////////////////////////////////////
// typing environment
////////////////////////////////////////////////////////////////////////////////
ConvertToNumber::ConvertToNumber(Engine *engine)
    : _engine(engine), _result(0)
{
}

const Value *ConvertToNumber::operator()(const Value *value)
{
    const Value *previousValue = switchResult(0);

    if (value)
        value->accept(this);

    return switchResult(previousValue);
}

const Value *ConvertToNumber::switchResult(const Value *value)
{
    const Value *previousResult = _result;
    _result = value;
    return previousResult;
}

ConvertToString::ConvertToString(Engine *engine)
    : _engine(engine), _result(0)
{
}

const Value *ConvertToString::operator()(const Value *value)
{
    const Value *previousValue = switchResult(0);

    if (value)
        value->accept(this);

    return switchResult(previousValue);
}

const Value *ConvertToString::switchResult(const Value *value)
{
    const Value *previousResult = _result;
    _result = value;
    return previousResult;
}

ConvertToObject::ConvertToObject(Engine *engine)
    : _engine(engine), _result(0)
{
}

const Value *ConvertToObject::operator()(const Value *value)
{
    const Value *previousValue = switchResult(0);

    if (value)
        value->accept(this);

    return switchResult(previousValue);
}

const Value *ConvertToObject::switchResult(const Value *value)
{
    const Value *previousResult = _result;
    _result = value;
    return previousResult;
}

void ConvertToObject::visit(const NullValue *value)
{
    _result = value;
}

void ConvertToObject::visit(const UndefinedValue *)
{
    _result = _engine->nullValue();
}

void ConvertToObject::visit(const NumberValue *value)
{
    ValueList actuals;
    actuals.append(value);
    _result = _engine->numberCtor()->construct(actuals);
}

void ConvertToObject::visit(const BooleanValue *value)
{
    ValueList actuals;
    actuals.append(value);
    _result = _engine->booleanCtor()->construct(actuals);
}

void ConvertToObject::visit(const StringValue *value)
{
    ValueList actuals;
    actuals.append(value);
    _result = _engine->stringCtor()->construct(actuals);
}

void ConvertToObject::visit(const ObjectValue *object)
{
    _result = object;
}

void ConvertToObject::visit(const FunctionValue *object)
{
    _result = object;
}

QString TypeId::operator()(const Value *value)
{
    _result = QLatin1String("unknown");

    if (value)
        value->accept(this);

    return _result;
}

void TypeId::visit(const NullValue *)
{
    _result = QLatin1String("null");
}

void TypeId::visit(const UndefinedValue *)
{
    _result = QLatin1String("undefined");
}

void TypeId::visit(const NumberValue *)
{
    _result = QLatin1String("number");
}

void TypeId::visit(const BooleanValue *)
{
    _result = QLatin1String("boolean");
}

void TypeId::visit(const StringValue *)
{
    _result = QLatin1String("string");
}

void TypeId::visit(const ObjectValue *object)
{
    _result = object->className();

    if (_result.isEmpty())
        _result = QLatin1String("object");
}

void TypeId::visit(const FunctionValue *object)
{
    _result = object->className();

    if (_result.isEmpty())
        _result = QLatin1String("Function");
}

Engine::Engine()
    : _objectPrototype(0),
      _functionPrototype(0),
      _numberPrototype(0),
      _booleanPrototype(0),
      _stringPrototype(0),
      _arrayPrototype(0),
      _datePrototype(0),
      _regexpPrototype(0),
      _objectCtor(0),
      _functionCtor(0),
      _arrayCtor(0),
      _stringCtor(0),
      _booleanCtor(0),
      _numberCtor(0),
      _dateCtor(0),
      _regexpCtor(0),
      _globalObject(0),
      _mathObject(0),
#ifndef NO_DECLARATIVE_BACKEND
      _qmlKeysObject(0),
#endif
      _convertToNumber(this),
      _convertToString(this),
      _convertToObject(this)
{

    initializePrototypes();
}

Engine::~Engine()
{
    QList<ObjectValue *>::iterator it = _objects.begin();

    for (; it != _objects.end(); ++it)
        delete *it;
}

const NullValue *Engine::nullValue() const
{
    return &_nullValue;
}

const UndefinedValue *Engine::undefinedValue() const
{
    return &_undefinedValue;
}

const NumberValue *Engine::numberValue() const
{
    return &_numberValue;
}

const BooleanValue *Engine::booleanValue() const
{
    return &_booleanValue;
}

const StringValue *Engine::stringValue() const
{
    return &_stringValue;
}

const Value *Engine::newArray()
{
    return arrayCtor()->construct();
}

ObjectValue *Engine::newObject()
{
    return newObject(_objectPrototype);
}

ObjectValue *Engine::newObject(const ObjectValue *prototype)
{
    ObjectValue *object = new ObjectValue(this);
    object->setPrototype(prototype);
    _objects.push_back(object);
    return object;
}

Function *Engine::newFunction() {
    Function *function = new Function(this);
    function->setPrototype(functionPrototype());
    _objects.push_back(function);
    return function;
}

ObjectValue *Engine::globalObject() const
{
    return _globalObject;
}

ObjectValue *Engine::objectPrototype() const
{
    return _objectPrototype;
}

ObjectValue *Engine::functionPrototype() const
{
    return _functionPrototype;
}

ObjectValue *Engine::numberPrototype() const
{
    return _numberPrototype;
}

ObjectValue *Engine::booleanPrototype() const
{
    return _booleanPrototype;
}

ObjectValue *Engine::stringPrototype() const
{
    return _stringPrototype;
}

ObjectValue *Engine::arrayPrototype() const
{
    return _arrayPrototype;
}

ObjectValue *Engine::datePrototype() const
{
    return _datePrototype;
}

ObjectValue *Engine::regexpPrototype() const
{
    return _regexpPrototype;
}

const FunctionValue *Engine::objectCtor() const
{
    return _objectCtor;
}

const FunctionValue *Engine::functionCtor() const
{
    return _functionCtor;
}

const FunctionValue *Engine::arrayCtor() const
{
    return _arrayCtor;
}

const FunctionValue *Engine::stringCtor() const
{
    return _stringCtor;
}

const FunctionValue *Engine::booleanCtor() const
{
    return _booleanCtor;
}

const FunctionValue *Engine::numberCtor() const
{
    return _numberCtor;
}

const FunctionValue *Engine::dateCtor() const
{
    return _dateCtor;
}

const FunctionValue *Engine::regexpCtor() const
{
    return _regexpCtor;
}

const ObjectValue *Engine::mathObject() const
{
    return _mathObject;
}

void Engine::registerObject(ObjectValue *object)
{
    _objects.append(object);
}

const Value *Engine::convertToBoolean(const Value *value)
{
    return _convertToNumber(value);  // ### implement convert to bool
}

const Value *Engine::convertToNumber(const Value *value)
{
    return _convertToNumber(value);
}

const Value *Engine::convertToString(const Value *value)
{
    return _convertToString(value);
}

const Value *Engine::convertToObject(const Value *value)
{
    return _convertToObject(value);
}

QString Engine::typeId(const Value *value)
{
    return _typeId(value);
}

void Engine::addFunction(ObjectValue *object, const QString &name, const Value *result, int argumentCount)
{
    Function *function = newFunction();
    function->setReturnValue(result);
    for (int i = 0; i < argumentCount; ++i)
        function->addArgument(undefinedValue()); // ### introduce unknownValue
    object->setProperty(name, function);
}

void Engine::addFunction(ObjectValue *object, const QString &name, int argumentCount)
{
    Function *function = newFunction();
    for (int i = 0; i < argumentCount; ++i)
        function->addArgument(undefinedValue()); // ### introduce unknownValue
    object->setProperty(name, function);
}

void Engine::initializePrototypes()
{
    _objectPrototype   = newObject(/*prototype = */ 0);
    _functionPrototype = newObject(_objectPrototype);
    _numberPrototype   = newObject(_objectPrototype);
    _booleanPrototype  = newObject(_objectPrototype);
    _stringPrototype   = newObject(_objectPrototype);
    _arrayPrototype    = newObject(_objectPrototype);
    _datePrototype     = newObject(_objectPrototype);
    _regexpPrototype   = newObject(_objectPrototype);

    // set up the Global object
    _globalObject = newObject();
    _globalObject->setClassName("Global");

    // set up the default Object prototype
    _objectCtor = new ObjectCtor(this);
    _objectCtor->setPrototype(_functionPrototype);
    _objects.push_back(_objectCtor);
    _objectCtor->setProperty("prototype", _objectPrototype);

    _functionCtor = new FunctionCtor(this);
    _functionCtor->setPrototype(_functionPrototype);
    _objects.push_back(_functionCtor);
    _functionCtor->setProperty("prototype", _functionPrototype);

    _arrayCtor = new ArrayCtor(this);
    _arrayCtor->setPrototype(_functionPrototype);
    _objects.push_back(_arrayCtor);
    _arrayCtor->setProperty("prototype", _arrayPrototype);

    _stringCtor = new StringCtor(this);
    _stringCtor->setPrototype(_functionPrototype);
    _objects.push_back(_stringCtor);
    _stringCtor->setProperty("prototype", _stringPrototype);

    _booleanCtor = new BooleanCtor(this);
    _booleanCtor->setPrototype(_functionPrototype);
    _objects.push_back(_booleanCtor);
    _booleanCtor->setProperty("prototype", _booleanPrototype);

    _numberCtor = new NumberCtor(this);
    _numberCtor->setPrototype(_functionPrototype);
    _objects.push_back(_numberCtor);
    _numberCtor->setProperty("prototype", _numberPrototype);

    _dateCtor = new DateCtor(this);
    _dateCtor->setPrototype(_functionPrototype);
    _objects.push_back(_dateCtor);
    _dateCtor->setProperty("prototype", _datePrototype);

    _regexpCtor = new RegExpCtor(this);
    _regexpCtor->setPrototype(_functionPrototype);
    _objects.push_back(_regexpCtor);
    _regexpCtor->setProperty("prototype", _regexpPrototype);

    addFunction(_objectCtor, "getPrototypeOf", 1);
    addFunction(_objectCtor, "getOwnPropertyDescriptor", 2);
    addFunction(_objectCtor, "getOwnPropertyNames", newArray(), 1);
    addFunction(_objectCtor, "create", 1);
    addFunction(_objectCtor, "defineProperty", 3);
    addFunction(_objectCtor, "defineProperties", 2);
    addFunction(_objectCtor, "seal", 1);
    addFunction(_objectCtor, "freeze", 1);
    addFunction(_objectCtor, "preventExtensions", 1);
    addFunction(_objectCtor, "isSealed", booleanValue(), 1);
    addFunction(_objectCtor, "isFrozen", booleanValue(), 1);
    addFunction(_objectCtor, "isExtensible", booleanValue(), 1);
    addFunction(_objectCtor, "keys", newArray(), 1);

    addFunction(_objectPrototype, "toString", stringValue(), 0);
    addFunction(_objectPrototype, "toLocaleString", stringValue(), 0);
    addFunction(_objectPrototype, "valueOf", 0); // ### FIXME it should return thisObject
    addFunction(_objectPrototype, "hasOwnProperty", booleanValue(), 1);
    addFunction(_objectPrototype, "isPrototypeOf", booleanValue(), 1);
    addFunction(_objectPrototype, "propertyIsEnumerable", booleanValue(), 1);

    // set up the default Function prototype
    _functionPrototype->setProperty("constructor", _functionCtor);
    addFunction(_functionPrototype, "toString", stringValue(), 0);
    addFunction(_functionPrototype, "apply", 2);
    addFunction(_functionPrototype, "call", 1);
    addFunction(_functionPrototype, "bind", 1);

    // set up the default Array prototype
    addFunction(_arrayCtor, "isArray", booleanValue(), 1);

    _arrayPrototype->setProperty("constructor", _arrayCtor);
    addFunction(_arrayPrototype, "toString", stringValue(), 0);
    addFunction(_arrayPrototype, "toLocalString", stringValue(), 0);
    addFunction(_arrayPrototype, "concat", 0);
    addFunction(_arrayPrototype, "join", 1);
    addFunction(_arrayPrototype, "pop", 0);
    addFunction(_arrayPrototype, "push", 0);
    addFunction(_arrayPrototype, "reverse", 0);
    addFunction(_arrayPrototype, "shift", 0);
    addFunction(_arrayPrototype, "slice", 2);
    addFunction(_arrayPrototype, "sort", 1);
    addFunction(_arrayPrototype, "splice", 2);
    addFunction(_arrayPrototype, "unshift", 0);
    addFunction(_arrayPrototype, "indexOf", numberValue(), 1);
    addFunction(_arrayPrototype, "lastIndexOf", numberValue(), 1);
    addFunction(_arrayPrototype, "every", 1);
    addFunction(_arrayPrototype, "some", 1);
    addFunction(_arrayPrototype, "forEach", 1);
    addFunction(_arrayPrototype, "map", 1);
    addFunction(_arrayPrototype, "filter", 1);
    addFunction(_arrayPrototype, "reduce", 1);
    addFunction(_arrayPrototype, "reduceRight", 1);

    // set up the default String prototype
    addFunction(_stringCtor, "fromCharCode", stringValue(), 0);

    _stringPrototype->setProperty("constructor", _stringCtor);
    addFunction(_stringPrototype, "toString", stringValue(), 0);
    addFunction(_stringPrototype, "valueOf", stringValue(), 0);
    addFunction(_stringPrototype, "charAt", stringValue(), 1);
    addFunction(_stringPrototype, "charCodeAt", stringValue(), 1);
    addFunction(_stringPrototype, "concat", stringValue(), 0);
    addFunction(_stringPrototype, "indexOf", numberValue(), 2);
    addFunction(_stringPrototype, "lastIndexOf", numberValue(), 2);
    addFunction(_stringPrototype, "localeCompare", booleanValue(), 1);
    addFunction(_stringPrototype, "match", newArray(), 1);
    addFunction(_stringPrototype, "replace", stringValue(), 2);
    addFunction(_stringPrototype, "search", numberValue(), 1);
    addFunction(_stringPrototype, "slice", stringValue(), 2);
    addFunction(_stringPrototype, "split", newArray(), 1);
    addFunction(_stringPrototype, "substring", stringValue(), 2);
    addFunction(_stringPrototype, "toLowerCase", stringValue(), 0);
    addFunction(_stringPrototype, "toLocaleLowerCase", stringValue(), 0);
    addFunction(_stringPrototype, "toUpperCase", stringValue(), 0);
    addFunction(_stringPrototype, "toLocaleUpperCase", stringValue(), 0);
    addFunction(_stringPrototype, "trim", stringValue(), 0);

    // set up the default Boolean prototype
    addFunction(_booleanCtor, "fromCharCode", 0);

    _booleanPrototype->setProperty("constructor", _booleanCtor);
    addFunction(_booleanPrototype, "toString", stringValue(), 0);
    addFunction(_booleanPrototype, "valueOf", booleanValue(), 0);

    // set up the default Number prototype
    _numberCtor->setProperty("MAX_VALUE", numberValue());
    _numberCtor->setProperty("MIN_VALUE", numberValue());
    _numberCtor->setProperty("NaN", numberValue());
    _numberCtor->setProperty("NEGATIVE_INFINITY", numberValue());
    _numberCtor->setProperty("POSITIVE_INFINITY", numberValue());

    addFunction(_numberCtor, "fromCharCode", 0);

    _numberPrototype->setProperty("constructor", _numberCtor);
    addFunction(_numberPrototype, "toString", stringValue(), 0);
    addFunction(_numberPrototype, "toLocaleString", stringValue(), 0);
    addFunction(_numberPrototype, "valueOf", numberValue(), 0);
    addFunction(_numberPrototype, "toFixed", numberValue(), 1);
    addFunction(_numberPrototype, "toExponential", numberValue(), 1);
    addFunction(_numberPrototype, "toPrecision", numberValue(), 1);

    // set up the Math object
    _mathObject = newObject();
    _mathObject->setProperty("E", numberValue());
    _mathObject->setProperty("LN10", numberValue());
    _mathObject->setProperty("LN2", numberValue());
    _mathObject->setProperty("LOG2E", numberValue());
    _mathObject->setProperty("LOG10E", numberValue());
    _mathObject->setProperty("PI", numberValue());
    _mathObject->setProperty("SQRT1_2", numberValue());
    _mathObject->setProperty("SQRT2", numberValue());

    addFunction(_mathObject, "abs", numberValue(), 1);
    addFunction(_mathObject, "acos", numberValue(), 1);
    addFunction(_mathObject, "asin", numberValue(), 1);
    addFunction(_mathObject, "atan", numberValue(), 1);
    addFunction(_mathObject, "atan2", numberValue(), 2);
    addFunction(_mathObject, "ceil", numberValue(), 1);
    addFunction(_mathObject, "cos", numberValue(), 1);
    addFunction(_mathObject, "exp", numberValue(), 1);
    addFunction(_mathObject, "floor", numberValue(), 1);
    addFunction(_mathObject, "log", numberValue(), 1);
    addFunction(_mathObject, "max", numberValue(), 0);
    addFunction(_mathObject, "min", numberValue(), 0);
    addFunction(_mathObject, "pow", numberValue(), 2);
    addFunction(_mathObject, "random", numberValue(), 1);
    addFunction(_mathObject, "round", numberValue(), 1);
    addFunction(_mathObject, "sin", numberValue(), 1);
    addFunction(_mathObject, "sqrt", numberValue(), 1);
    addFunction(_mathObject, "tan", numberValue(), 1);

    // set up the default Boolean prototype
    addFunction(_dateCtor, "parse", numberValue(), 1);
    addFunction(_dateCtor, "now", numberValue(), 0);

    _datePrototype->setProperty("constructor", _dateCtor);
    addFunction(_datePrototype, "toString", stringValue(), 0);
    addFunction(_datePrototype, "toDateString", stringValue(), 0);
    addFunction(_datePrototype, "toTimeString", stringValue(), 0);
    addFunction(_datePrototype, "toLocaleString", stringValue(), 0);
    addFunction(_datePrototype, "toLocaleDateString", stringValue(), 0);
    addFunction(_datePrototype, "toLocaleTimeString", stringValue(), 0);
    addFunction(_datePrototype, "valueOf", numberValue(), 0);
    addFunction(_datePrototype, "getTime", numberValue(), 0);
    addFunction(_datePrototype, "getFullYear", numberValue(), 0);
    addFunction(_datePrototype, "getUTCFullYear", numberValue(), 0);
    addFunction(_datePrototype, "getMonth", numberValue(), 0);
    addFunction(_datePrototype, "getUTCMonth", numberValue(), 0);
    addFunction(_datePrototype, "getDate", numberValue(), 0);
    addFunction(_datePrototype, "getUTCDate", numberValue(), 0);
    addFunction(_datePrototype, "getHours", numberValue(), 0);
    addFunction(_datePrototype, "getUTCHours", numberValue(), 0);
    addFunction(_datePrototype, "getMinutes", numberValue(), 0);
    addFunction(_datePrototype, "getUTCMinutes", numberValue(), 0);
    addFunction(_datePrototype, "getSeconds", numberValue(), 0);
    addFunction(_datePrototype, "getUTCSeconds", numberValue(), 0);
    addFunction(_datePrototype, "getMilliseconds", numberValue(), 0);
    addFunction(_datePrototype, "getUTCMilliseconds", numberValue(), 0);
    addFunction(_datePrototype, "getTimezoneOffset", numberValue(), 0);
    addFunction(_datePrototype, "setTime", 1);
    addFunction(_datePrototype, "setMilliseconds", 1);
    addFunction(_datePrototype, "setUTCMilliseconds", 1);
    addFunction(_datePrototype, "setSeconds", 1);
    addFunction(_datePrototype, "setUTCSeconds", 1);
    addFunction(_datePrototype, "setMinutes", 1);
    addFunction(_datePrototype, "setUTCMinutes", 1);
    addFunction(_datePrototype, "setHours", 1);
    addFunction(_datePrototype, "setUTCHours", 1);
    addFunction(_datePrototype, "setDate", 1);
    addFunction(_datePrototype, "setUTCDate", 1);
    addFunction(_datePrototype, "setMonth", 1);
    addFunction(_datePrototype, "setUTCMonth", 1);
    addFunction(_datePrototype, "setFullYear", 1);
    addFunction(_datePrototype, "setUTCFullYear", 1);
    addFunction(_datePrototype, "toUTCString", stringValue(), 0);
    addFunction(_datePrototype, "toISOString", stringValue(), 0);
    addFunction(_datePrototype, "toJSON", stringValue(), 1);

    // set up the default Boolean prototype
    _regexpPrototype->setProperty("constructor", _regexpCtor);
    addFunction(_regexpPrototype, "exec", newArray(), 1);
    addFunction(_regexpPrototype, "test", booleanValue(), 1);
    addFunction(_regexpPrototype, "toString", stringValue(), 0);

    // fill the Global object
    _globalObject->setProperty("Math", _mathObject);
    _globalObject->setProperty("Object", objectCtor());
    _globalObject->setProperty("Function", functionCtor());
    _globalObject->setProperty("Array", arrayCtor());
    _globalObject->setProperty("String", stringCtor());
    _globalObject->setProperty("Boolean", booleanCtor());
    _globalObject->setProperty("Number", numberCtor());
    _globalObject->setProperty("Date", dateCtor());
    _globalObject->setProperty("RegExp", regexpCtor());

#ifndef NO_DECLARATIVE_BACKEND
    _qmlKeysObject = new QmlAttachedKeys(this);
    _globalObject->setProperty("Keys", _qmlKeysObject); // ### attach it to the current scope, and not to the global object
    registerObject(_qmlKeysObject);
#endif
}

const ObjectValue *Engine::qmlKeysObject()
{
#ifndef NO_DECLARATIVE_BACKEND
    return _qmlKeysObject;
#else
    return 0;
#endif
}

const Value *Engine::defaultValueForBuiltinType(const QString &typeName) const
{
    if (typeName == QLatin1String("string") || typeName == QLatin1String("url"))
        return stringValue();
    else if (typeName == QLatin1String("bool"))
        return booleanValue();
    else if (typeName == QLatin1String("int") || typeName == QLatin1String("real"))
        return numberValue();
    // ### more types...

    return undefinedValue();
}

ObjectValue *Engine::newQmlObject(const QString &name)
{
#ifndef NO_DECLARATIVE_BACKEND
    if (name == QLatin1String("QmlGraphicsAnchors")) {
        QmlObjectValue *object = new QmlObjectValue(&QmlGraphicsAnchors::staticMetaObject, this);
        _objects.append(object);
        return object;
    } else if (name == QLatin1String("QmlGraphicsPen")) {
        QmlObjectValue *object = new QmlObjectValue(&QmlGraphicsPen::staticMetaObject, this);
        _objects.append(object);
        return object;
    } else if (name == QLatin1String("QmlGraphicsScaleGrid")) {
        ObjectValue *object = newObject(/*prototype =*/ 0);
        object->setProperty("left", numberValue());
        object->setProperty("top", numberValue());
        object->setProperty("right", numberValue());
        object->setProperty("bottom", numberValue());
        return object;
    }

    // ### TODO: add support for QML packages
    QString componentName;
    componentName += QLatin1String("Qt/");
    componentName += name;
    componentName.replace(QLatin1Char('.'), QLatin1Char('/'));

    if (QmlType *qmlType = QmlMetaType::qmlType(componentName.toUtf8(), 4, 6)) {
        QmlObjectValue *object = new QmlObjectValue(qmlType->metaObject(), this);
        _objects.append(object);
        return object;
    }

    return 0;
#else
    return newObject(/*prototype = */ 0);
#endif
}

////////////////////////////////////////////////////////////////////////////////
// convert to number
////////////////////////////////////////////////////////////////////////////////
void ConvertToNumber::visit(const NullValue *)
{
    _result = _engine->numberValue();
}

void ConvertToNumber::visit(const UndefinedValue *)
{
    _result = _engine->numberValue();
}

void ConvertToNumber::visit(const NumberValue *value)
{
    _result = value;
}

void ConvertToNumber::visit(const BooleanValue *)
{
    _result = _engine->numberValue();
}

void ConvertToNumber::visit(const StringValue *)
{
    _result = _engine->numberValue();
}

void ConvertToNumber::visit(const ObjectValue *object)
{
    if (const FunctionValue *valueOfMember = value_cast<const FunctionValue *>(object->lookup("valueOf"))) {
        _result = value_cast<const NumberValue *>(valueOfMember->call(object)); // ### invoke convert-to-number?
    }
}

void ConvertToNumber::visit(const FunctionValue *object)
{
    if (const FunctionValue *valueOfMember = value_cast<const FunctionValue *>(object->lookup("valueOf"))) {
        _result = value_cast<const NumberValue *>(valueOfMember->call(object)); // ### invoke convert-to-number?
    }
}

////////////////////////////////////////////////////////////////////////////////
// convert to string
////////////////////////////////////////////////////////////////////////////////
void ConvertToString::visit(const NullValue *)
{
    _result = _engine->stringValue();
}

void ConvertToString::visit(const UndefinedValue *)
{
    _result = _engine->stringValue();
}

void ConvertToString::visit(const NumberValue *)
{
    _result = _engine->stringValue();
}

void ConvertToString::visit(const BooleanValue *)
{
    _result = _engine->stringValue();
}

void ConvertToString::visit(const StringValue *value)
{
    _result = value;
}

void ConvertToString::visit(const ObjectValue *object)
{
    if (const FunctionValue *toStringMember = value_cast<const FunctionValue *>(object->lookup("toString"))) {
        _result = value_cast<const StringValue *>(toStringMember->call(object)); // ### invoke convert-to-string?
    }
}

void ConvertToString::visit(const FunctionValue *object)
{
    if (const FunctionValue *toStringMember = value_cast<const FunctionValue *>(object->lookup("toString"))) {
        _result = value_cast<const StringValue *>(toStringMember->call(object)); // ### invoke convert-to-string?
    }
}