qv4argumentsobject.cpp

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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
 
#include "qv4argumentsobject_p.h"
 
#include <private/qv4alloca_p.h>
#include <private/qv4arrayobject_p.h>
#include <private/qv4function_p.h>
#include <private/qv4jscall_p.h>
#include <private/qv4scopedvalue_p.h>
#include <private/qv4stackframe_p.h>
#include <private/qv4string_p.h>
#include <private/qv4symbol_p.h>
 
using namespace QV4;
 
DEFINE_OBJECT_VTABLE(ArgumentsObject);
DEFINE_OBJECT_VTABLE(StrictArgumentsObject);
 
void Heap::StrictArgumentsObject::init(QV4::JSTypesStackFrame *frame)
 
{
    Q_ASSERT(vtable() == QV4::StrictArgumentsObject::staticVTable());
    ExecutionEngine *v4 = internalClass->engine;
 
    Object::init();
 
    Q_ASSERT(internalClass->verifyIndex(v4->id_callee()->propertyKey(), CalleePropertyIndex));
    Q_ASSERT(internalClass->findValueOrSetter(v4->id_callee()->propertyKey()).index == CalleeSetterPropertyIndex);
    Q_ASSERT(internalClass->verifyIndex(v4->symbol_iterator()->propertyKey(), SymbolIteratorPropertyIndex));
    setProperty(v4, SymbolIteratorPropertyIndex, *v4->arrayProtoValues());
    setProperty(v4, CalleePropertyIndex, *v4->thrower());
    setProperty(v4, CalleeSetterPropertyIndex, *v4->thrower());
 
    Scope scope(v4);
    Scoped<QV4::StrictArgumentsObject> args(scope, this);
    args->arrayReserve(frame->argc());
    args->arrayPut(0, frame->argv(), frame->argc());
 
    Q_ASSERT(args->internalClass()->verifyIndex(v4->id_length()->propertyKey(), LengthPropertyIndex));
    setProperty(v4, LengthPropertyIndex, Value::fromInt32(frame->argc()));
}
 
void Heap::ArgumentsObject::init(QV4::CppStackFrame *frame)
{
    ExecutionEngine *v4 = internalClass->engine;
 
    QV4::CallContext *context = static_cast<QV4::CallContext *>(frame->context());
 
    Object::init();
    this->context.set(v4, context->d());
    Q_ASSERT(vtable() == QV4::ArgumentsObject::staticVTable());
 
    Q_ASSERT(internalClass->verifyIndex(v4->id_callee()->propertyKey(), CalleePropertyIndex));
    setProperty(v4, CalleePropertyIndex, context->d()->function);
    Q_ASSERT(internalClass->verifyIndex(v4->id_length()->propertyKey(), LengthPropertyIndex));
    setProperty(v4, LengthPropertyIndex, Value::fromInt32(context->argc()));
    Q_ASSERT(internalClass->verifyIndex(v4->symbol_iterator()->propertyKey(), SymbolIteratorPropertyIndex));
    setProperty(v4, SymbolIteratorPropertyIndex, *v4->arrayProtoValues());
 
    fullyCreated = false;
    argCount = frame->argc();
    uint nFormals = frame->v4Function->nFormals;
    mapped = nFormals > 63 ? std::numeric_limits<quint64>::max() : (1ull << nFormals) - 1;
}
 
void ArgumentsObject::fullyCreate()
{
    if (d()->fullyCreated)
        return;
 
    Scope scope(engine());
 
    arrayReserve(d()->argCount);
    arrayPut(0, context()->args(), d()->argCount);
    // Use a sparse array, so that method_getElement() doesn't shortcut
    initSparseArray();
 
    d()->fullyCreated = true;
}
 
bool ArgumentsObject::virtualDefineOwnProperty(Managed *m, PropertyKey id, const Property *desc, PropertyAttributes attrs)
{
    ArgumentsObject *args = static_cast<ArgumentsObject *>(m);
    args->fullyCreate();
    if (!id.isArrayIndex())
        return Object::virtualDefineOwnProperty(m, id, desc, attrs);
 
    uint index = id.asArrayIndex();
 
    if (!args->isMapped(index))
        return Object::virtualDefineOwnProperty(m, id, desc, attrs);
 
    Scope scope(args);
    PropertyAttributes cAttrs = attrs;
    ScopedProperty cDesc(scope);
    cDesc->copy(desc, attrs);
 
    if (attrs.isData() && desc->value.isEmpty() && attrs.hasWritable() && !attrs.isWritable()) {
        cDesc->value = args->context()->args()[index];
        cAttrs.setType(PropertyAttributes::Data);
    }
 
    bool allowed = Object::virtualDefineOwnProperty(m, id, cDesc, cAttrs);
    if (!allowed)
        return false;
 
    if (attrs.isAccessor()) {
        args->removeMapping(index);
    } else {
        if (!desc->value.isEmpty())
            args->context()->setArg(index, desc->value);
        if (attrs.hasWritable() && !attrs.isWritable())
            args->removeMapping(index);
    }
    return true;
}
 
ReturnedValue ArgumentsObject::virtualGet(const Managed *m, PropertyKey id, const Value *receiver, bool *hasProperty)
{
    if (id.isArrayIndex()) {
        const ArgumentsObject *args = static_cast<const ArgumentsObject *>(m);
        uint index = id.asArrayIndex();
        if (index < args->d()->argCount && !args->d()->fullyCreated) {
            if (hasProperty)
                *hasProperty = true;
            return args->context()->args()[index].asReturnedValue();
        }
 
        if (args->isMapped(index)) {
            Q_ASSERT(index < static_cast<uint>(args->context()->function->formalParameterCount()));
            if (hasProperty)
                *hasProperty = true;
            return args->context()->args()[index].asReturnedValue();
        }
    }
 
    return Object::virtualGet(m, id, receiver, hasProperty);
}
 
bool ArgumentsObject::virtualPut(Managed *m, PropertyKey id, const Value &value, Value *receiver)
{
    if (id.isArrayIndex()) {
        ArgumentsObject *args = static_cast<ArgumentsObject *>(m);
        uint index = id.asArrayIndex();
 
        if (args == receiver && index < args->d()->argCount && !args->d()->fullyCreated) {
            args->context()->setArg(index, value);
            return true;
        }
 
        bool isMapped = (args == receiver && args->isMapped(index));
        if (isMapped)
            args->context()->setArg(index, value);
    }
 
    return Object::virtualPut(m, id, value, receiver);
}
 
bool ArgumentsObject::virtualDeleteProperty(Managed *m, PropertyKey id)
{
    ArgumentsObject *args = static_cast<ArgumentsObject *>(m);
    args->fullyCreate();
    bool result = Object::virtualDeleteProperty(m, id);
    if (result && id.isArrayIndex())
        args->removeMapping(id.asArrayIndex());
    return result;
}
 
PropertyAttributes ArgumentsObject::virtualGetOwnProperty(const Managed *m, PropertyKey id, Property *p)
{
    if (!id.isArrayIndex())
        return Object::virtualGetOwnProperty(m, id, p);
 
    const ArgumentsObject *args = static_cast<const ArgumentsObject *>(m);
    uint index = id.asArrayIndex();
    if (index < args->d()->argCount && !args->d()->fullyCreated) {
        p->value = args->context()->args()[index];
        return Attr_Data;
    }
 
    PropertyAttributes attrs = Object::virtualGetOwnProperty(m, id, p);
    if (attrs.isEmpty() || !args->isMapped(index))
        return attrs;
 
    Q_ASSERT(index < static_cast<uint>(args->context()->function->formalParameterCount()));
    if (p)
        p->value = args->context()->args()[index];
    return attrs;
}
 
qint64 ArgumentsObject::virtualGetLength(const Managed *m)
{
    const ArgumentsObject *a = static_cast<const ArgumentsObject *>(m);
    return a->propertyData(Heap::ArgumentsObject::LengthPropertyIndex)->toLength();
}
 
OwnPropertyKeyIterator *ArgumentsObject::virtualOwnPropertyKeys(const Object *m, Value *target)
{
    static_cast<ArgumentsObject *>(const_cast<Object *>(m))->fullyCreate();
    return Object::virtualOwnPropertyKeys(m, target);
}