C++ QScriptEnginePrivate类代码示例

bool ClassObjectDelegate::getOwnPropertySlot(QScriptObject* object,
                                             JSC::ExecState *exec,
                                             const JSC::Identifier &propertyName,
                                             JSC::PropertySlot &slot)
{
    QScriptEnginePrivate *engine = scriptEngineFromExec(exec);
    QScript::SaveFrameHelper saveFrame(engine, exec);
    // for compatibility with the old back-end, normal JS properties
    // are queried first.
    if (QScriptObjectDelegate::getOwnPropertySlot(object, exec, propertyName, slot))
        return true;

    QScriptValue scriptObject = engine->scriptValueFromJSCValue(object);
    QScriptString scriptName;
    QScriptStringPrivate scriptName_d(engine, propertyName, QScriptStringPrivate::StackAllocated);
    QScriptStringPrivate::init(scriptName, &scriptName_d);
    uint id = 0;
    QScriptClass::QueryFlags flags = m_scriptClass->queryProperty(
        scriptObject, scriptName, QScriptClass::HandlesReadAccess, &id);
    if (flags & QScriptClass::HandlesReadAccess) {
        QScriptValue value = m_scriptClass->property(scriptObject, scriptName, id);
        slot.setValue(engine->scriptValueToJSCValue(value));
        return true;
    }
    return false;
}

bool ClassObjectDelegate::getOwnPropertySlot(QScriptObject* object,
                                             JSC::ExecState *exec,
                                             const JSC::Identifier &propertyName,
                                             JSC::PropertySlot &slot)
{
    QScriptEnginePrivate *engine = scriptEngineFromExec(exec);
    QScript::SaveFrameHelper saveFrame(engine, exec);
    // for compatibility with the old back-end, normal JS properties
    // are queried first.
    if (QScriptObjectDelegate::getOwnPropertySlot(object, exec, propertyName, slot))
        return true;

    QScriptValue scriptObject = engine->scriptValueFromJSCValue(object);
    QScriptString scriptName;
    QScriptStringPrivate scriptName_d(engine, propertyName, QScriptStringPrivate::StackAllocated);
    QScriptStringPrivate::init(scriptName, &scriptName_d);
    uint id = 0;
    QScriptClass::QueryFlags flags = m_scriptClass->queryProperty(
        scriptObject, scriptName, QScriptClass::HandlesReadAccess, &id);
    if (flags & QScriptClass::HandlesReadAccess) {
        QScriptValue value = m_scriptClass->property(scriptObject, scriptName, id);
        if (!value.isValid()) {
            // The class claims to have the property, but returned an invalid
            // value. Silently convert to undefined to avoid the invalid value
            // "escaping" into JS.
            value = QScriptValue(QScriptValue::UndefinedValue);
        }
        slot.setValue(engine->scriptValueToJSCValue(value));
        return true;
    }
    return false;
}

/*!
  \internal
  \since 4.5

  Adds the given \a object to the front of this context's scope chain.

  If \a object is not an object, this function does nothing.
*/
void QScriptContext::pushScope(const QScriptValue &object)
{
    activationObject(); //ensure the creation of the normal scope for native context
    if (!object.isObject())
        return;
    else if (object.engine() != engine()) {
        qWarning("QScriptContext::pushScope() failed: "
                 "cannot push an object created in "
                 "a different engine");
        return;
    }
    JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    JSC::JSObject *jscObject = JSC::asObject(engine->scriptValueToJSCValue(object));
    if (jscObject == engine->originalGlobalObjectProxy)
        jscObject = engine->originalGlobalObject();
    JSC::ScopeChainNode *scope = frame->scopeChain();
    Q_ASSERT(scope != 0);
    if (!scope->object) {
        // pushing to an "empty" chain
        if (!jscObject->isGlobalObject()) {
            qWarning("QScriptContext::pushScope() failed: initial object in scope chain has to be the Global Object");
            return;
        }
        scope->object = jscObject;
    }
    else
        frame->setScopeChain(scope->push(jscObject));
}

bool QScriptValueImpl::hasInstance(const QScriptValueImpl &value) const
{
    Q_ASSERT(isObject());

    if (QScriptClassData *odata = classInfo()->data()) {
        if (odata->implementsHasInstance(*this))
            return odata->hasInstance(*this, value);
    }
    if (!isFunction())
        return false;

    // [[HasInstance] for function objects

    if (!value.isObject())
        return false;

    QScriptEnginePrivate *eng = engine();
    QScriptValueImpl proto = property(eng->idTable()->id_prototype);
    if (!proto.isObject()) {
        QScriptContextPrivate *ctx = eng->currentContext();
        ctx->throwTypeError(QLatin1String("instanceof: 'prototype' property is not an object"));
        return false;
    }

    QScriptObject *target = proto.m_object_value;
    QScriptValueImpl v = value;
    while (true) {
        v = v.prototype();
        if (!v.isObject())
            break;
        if (target == v.m_object_value)
            return true;
    }
    return false;
}

/*!
  Creates a new \c{Object} and calls this QScriptValue as a
  constructor, using the created object as the `this' object and
  passing \a arguments as arguments. If the return value from the
  constructor call is an object, then that object is returned;
  otherwise the default constructed object is returned.

  If this QScriptValue is not a function, construct() does nothing
  and returns an invalid QScriptValue.

  \a arguments can be an arguments object, an array, null or
  undefined. Any other type will cause a TypeError to be thrown.

  \sa call(), QScriptEngine::newObject(), QScriptContext::argumentsObject()
*/
QScriptValue QScriptValue::construct(const QScriptValue &arguments)
{
    Q_D(QScriptValue);
    if (!d || !d->value.isObject())
        return QScriptValue();
    QScriptEnginePrivate *eng = QScriptEnginePrivate::get(engine());
    return eng->toPublic(d->value.construct(eng->toImpl(arguments)));
}

/*!
  \since 4.4

  Sets the internal \a data of this QScriptValue object. You can use
  this function to set object-specific data that won't be directly
  accessible to scripts, but may be retrieved in C++ using the data()
  function.
*/
void QScriptValue::setData(const QScriptValue &data)
{
    Q_D(QScriptValue);
    if (!d || !d->value.isObject())
        return;
    QScriptEnginePrivate *eng = QScriptEnginePrivate::get(engine());
    d->value.setInternalValue(eng->toImpl(data));
}

/*!
    \since 4.6

    Returns the scope object of this QScriptValue. This function is only
    relevant for function objects. The scope determines how variables are
    resolved when the function is invoked.
*/
QScriptValue QScriptValue::scope() const
{
    Q_D(const QScriptValue);
    if (!d || !d->value.isObject())
        return QScriptValue();
    QScriptEnginePrivate *eng = QScriptEnginePrivate::get(engine());
    return eng->toPublic(d->value.scope());
}

/*!
  Returns the value of this QScriptValue's property with the given \a name,
  using the given \a mode to resolve the property.

  If no such property exists, an invalid QScriptValue is returned.

  If the property is implemented using a getter function (i.e. has the
  PropertyGetter flag set), calling property() has side-effects on the
  script engine, since the getter function will be called (possibly
  resulting in an uncaught script exception). If an exception
  occurred, property() returns the value that was thrown (typically
  an \c{Error} object).

  \sa setProperty(), propertyFlags(), QScriptValueIterator
*/
QScriptValue QScriptValue::property(const QString &name,
                                    const ResolveFlags &mode) const
{
    Q_D(const QScriptValue);
    if (!d || !d->value.isObject())
        return QScriptValue();
    QScriptEnginePrivate *eng = QScriptEnginePrivate::get(engine());
    return eng->toPublic(d->value.property(name, mode));
}

/*!
  \overload

  Returns the property at the given \a arrayIndex, using the given \a
  mode to resolve the property.

  This function is provided for convenience and performance when
  working with array objects.

  If this QScriptValue is not an Array object, this function behaves
  as if property() was called with the string representation of \a
  arrayIndex.
*/
QScriptValue QScriptValue::property(quint32 arrayIndex,
                                    const ResolveFlags &mode) const
{
    Q_D(const QScriptValue);
    if (!d || !d->value.isObject())
        return QScriptValue();
    QScriptEnginePrivate *eng = QScriptEnginePrivate::get(engine());
    return eng->toPublic(d->value.property(arrayIndex, mode));
}

/*!
  Returns the `this' object associated with this QScriptContext.
*/
QScriptValue QScriptContext::thisObject() const
{
    JSC::CallFrame *frame = const_cast<JSC::ExecState*>(QScriptEnginePrivate::frameForContext(this));
    QScriptEnginePrivate *engine = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(engine);
    JSC::JSValue result = engine->thisForContext(frame);
    if (!result || result.isNull())
        result = frame->globalThisValue();
    return engine->scriptValueFromJSCValue(result);
}

/*!
  Checks the syntax of the given \a program. Returns a
  QScriptSyntaxCheckResult object that contains the result of the check.
*/
QScriptSyntaxCheckResult QScriptEngine::checkSyntax(const QString &program)
{
    // FIXME This is not optimal.
    // The JSC C API needs a context to perform a syntax check, it means that a QScriptEnginePrivate
    // had to be created. This function is static so we have to create QScriptEnginePrivate for each
    // call. We can't remove the "static" for compatibility reason, at least up to Qt5.
    // QScriptSyntaxCheckResultPrivate takes ownership of newly created engine. The engine will be
    // kept as long as it is needed for lazy evaluation of properties of
    // the QScriptSyntaxCheckResultPrivate.
    QScriptEnginePrivate* engine = new QScriptEnginePrivate(/* q_ptr */ 0);
    return QScriptSyntaxCheckResultPrivate::get(engine->checkSyntax(program));
}

void EnumerationClassData::mark(const QScriptValueImpl &object, int generation)
{
    Q_ASSERT(object.isValid());

    QScriptEnginePrivate *eng = object.engine();

    if (Enumeration::Instance *instance = Enumeration::Instance::get(object, classInfo())) {
        eng->markObject(instance->object, generation);
        if (instance->it)
            eng->markObject(instance->it->object(), generation);
    }
}

/*!
  Returns the callee. The callee is the function object that this
  QScriptContext represents an invocation of.
*/
QScriptValue QScriptContext::callee() const
{
    const JSC::CallFrame *frame = QScriptEnginePrivate::frameForContext(this);
    QScriptEnginePrivate *eng = QScript::scriptEngineFromExec(frame);
    QScript::APIShim shim(eng);
    if (frame->callee() == eng->originalGlobalObject()) {
        // This is a pushContext()-created context; the callee is a lie.
        Q_ASSERT(QScriptEnginePrivate::contextFlags(const_cast<JSC::CallFrame*>(frame)) & QScriptEnginePrivate::NativeContext);
        return QScriptValue();
    }
    return eng->scriptValueFromJSCValue(frame->callee());
}

QScriptValue QScriptDeclarativeClass::newObject(QScriptEngine *engine, 
                                                QScriptDeclarativeClass *scriptClass, 
                                                Object *object)
{
    Q_ASSERT(engine);
    Q_ASSERT(scriptClass);

    QScriptEnginePrivate *p = static_cast<QScriptEnginePrivate *>(QObjectPrivate::get(engine)); 

    JSC::ExecState* exec = p->currentFrame;
    QScriptObject *result = new (exec) QScriptObject(p->scriptObjectStructure);
    result->setDelegate(new QScript::DeclarativeObjectDelegate(scriptClass, object));
    return p->scriptValueFromJSCValue(result);
}

void Function::initialize()
{
    QScriptEnginePrivate *eng = engine();
    eng->newConstructor(&ctor, this, publicPrototype);

    addPrototypeFunction(QLatin1String("toString"), method_toString, 1);
    addPrototypeFunction(QLatin1String("apply"), method_apply, 1);
    addPrototypeFunction(QLatin1String("call"), method_call, 1);
    addPrototypeFunction(QLatin1String("connect"), method_connect, 1);
    addPrototypeFunction(QLatin1String("disconnect"), method_disconnect, 1);

    QExplicitlySharedDataPointer<QScriptClassData> data(new FunctionClassData(classInfo()));
    classInfo()->setData(data);
}