xref: /dports/www/kf5-kjs/kjs-5.89.0/src/kjs/object.cpp

/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
 *  Copyright (C) 2003, 2004, 2005, 2006 Apple Computer, Inc.
 *  Copyright (C) 2007 Eric Seidel (eric@webkit.org)
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include "object.h"

#include "error_object.h"
#include "lookup.h"
#include "nodes.h"
#include "operations.h"
#include "PropertyNameArray.h"
#include <math.h>

#include <typeinfo>

#define JAVASCRIPT_MARK_TRACING 0

namespace KJS
{

// ------------------------------ JSObject ------------------------------------

void JSObject::mark()
{
    JSCell::mark();

#if JAVASCRIPT_MARK_TRACING
    static int markStackDepth = 0;
    markStackDepth++;
    for (int i = 0; i < markStackDepth; i++) {
        putchar('-');
    }

    printf("%s (%p)\n", className().UTF8String().c_str(), this);
#endif

    JSValue *proto = _proto;
    if (!JSValue::marked(proto)) {
        JSValue::mark(proto);
    }

    _prop.mark();

#if JAVASCRIPT_MARK_TRACING
    markStackDepth--;
#endif
}

JSType JSObject::type() const
{
    return ObjectType;
}

const ClassInfo *JSObject::classInfo() const
{
    return nullptr;
}

UString JSObject::className() const
{
    const ClassInfo *ci = classInfo();
    return ci ? ci->className : "Object";
}

JSValue *JSObject::get(ExecState *exec, const Identifier &propertyName) const
{
    PropertySlot slot;

    if (const_cast<JSObject *>(this)->getPropertySlot(exec, propertyName, slot)) {
        JSValue *val = slot.getValue(exec, const_cast<JSObject *>(this), propertyName);
        assert(val);
        return val;
    }

    return jsUndefined();
}

JSValue *JSObject::get(ExecState *exec, unsigned propertyName) const
{
    PropertySlot slot;
    if (const_cast<JSObject *>(this)->getPropertySlot(exec, propertyName, slot)) {
        return slot.getValue(exec, const_cast<JSObject *>(this), propertyName);
    }

    return jsUndefined();
}

bool JSObject::getPropertySlot(ExecState *exec, unsigned propertyName, PropertySlot &slot)
{
    JSObject *imp = this;

    while (true) {
        if (imp->getOwnPropertySlot(exec, propertyName, slot)) {
            return true;
        }

        JSValue *proto = imp->_proto;
        if (!JSValue::isObject(proto)) {
            break;
        }

        imp = static_cast<JSObject *>(proto);
    }

    return false;
}

bool JSObject::getPropertyDescriptor(ExecState *exec, const Identifier &propertyName, PropertyDescriptor &desc)
{
    JSObject *object = this;
    while (true) {
        if (object->getOwnPropertyDescriptor(exec, propertyName, desc)) {
            return true;
        }
        JSValue *prototype = object->prototype();
        if (!JSValue::isObject(prototype)) {
            return false;
        }
        object = JSValue::toObject(prototype, exec);
    }
}

bool JSObject::getOwnPropertySlot(ExecState *exec, unsigned propertyName, PropertySlot &slot)
{
    return getOwnPropertySlot(exec, Identifier::from(propertyName), slot);
}

// Ideally, we would like to inline this, since it's ultra-hot, but with the large VM
// loop, it seems like the code side gets the g++-4.3.x inliner in the paranoid mode, so not only
// does it not inline this, but it also doesn't inline setValueSlot() and hasGetterSetterProperties() (!!!).
bool JSObject::getOwnPropertySlot(ExecState *exec, const Identifier &propertyName, PropertySlot &slot)
{
    if (JSValue **location = getDirectLocation(propertyName)) {
        if (_prop.hasGetterSetterProperties() && JSValue::type(location[0]) == GetterSetterType) {
            fillGetterPropertySlot(slot, location);
        } else {
            slot.setValueSlot(this, location);
        }
        return true;
    }

    // non-standard Netscape extension
    if (propertyName == exec->propertyNames().underscoreProto) {
        slot.setValueSlot(this, &_proto);
        return true;
    }

    return false;
}

bool JSObject::getOwnPropertyDescriptor(ExecState *exec, const Identifier &identifier, PropertyDescriptor &desc)
{
    JSValue *jsVal = getDirect(identifier);

    // for classes that do not implement getDirect, like the prototypes,
    // we have to check if they still do own the property and use the propertyslot
    if (!jsVal) {
        PropertySlot slot;
        if (getOwnPropertySlot(exec, identifier, slot)) {
            jsVal = slot.getValue(exec, this, identifier);
        }
    }

    if (jsVal) {
        unsigned attr = 0;
        getPropertyAttributes(identifier, attr);
        return desc.setPropertyDescriptorValues(exec, jsVal, attr);
    }
    return false;
}

static void throwSetterError(ExecState *exec)
{
    throwError(exec, TypeError, "setting a property that has only a getter");
}

// ECMA 8.6.2.2
void JSObject::put(ExecState *exec, const Identifier &propertyName, JSValue *value, int attr)
{
    assert(value);

    // non-standard netscape extension
    if (propertyName == exec->propertyNames().underscoreProto) {
        JSObject *proto = JSValue::getObject(value);
        while (proto) {
            if (proto == this) {
                throwError(exec, GeneralError, "cyclic __proto__ value");
                return;
            }
            proto = proto->prototype() ? JSValue::getObject(proto->prototype()) : nullptr;
        }

        setPrototype(value);
        return;
    }

    // putValue() is used for JS assignments. It passes no attribute.
    // Assume that a C++ implementation knows what it is doing
    // and don't spend time doing a read-only check for it.
    bool checkRO = (attr == None || attr == DontDelete);

    if (checkRO) {
        // Check for static properties that are ReadOnly; the property map will check the dynamic properties.
        // We don't have to worry about setters being read-only as they can't be added with such an attribute.
        // We also need to inherit any attributes we have from the entry
        const HashEntry *entry = findPropertyHashEntry(propertyName);
        if (entry) {
            if (entry->attr & ReadOnly) {
#ifdef KJS_VERBOSE
                fprintf(stderr, "WARNING: static property %s is ReadOnly\n", propertyName.ascii());
#endif
                return;
            }
            attr = entry->attr;
        }
    }

    // Check if there are any setters or getters in the prototype chain
    JSObject *obj = this;
    bool hasGettersOrSetters = false;
    while (true) {
        if (obj->_prop.hasGetterSetterProperties()) {
            hasGettersOrSetters = true;
            break;
        }

        if (!JSValue::isObject(obj->_proto)) {
            break;
        }

        obj = static_cast<JSObject *>(obj->_proto);
    }

    if (hasGettersOrSetters) {
        obj = this;
        while (true) {
            unsigned attributes;
            if (JSValue *gs = obj->_prop.get(propertyName, attributes)) {
                if (attributes & GetterSetter) {
                    JSObject *setterFunc = static_cast<GetterSetterImp *>(gs)->getSetter();

                    if (!setterFunc) {
                        if (false) { //only throw if strict is set
                            throwSetterError(exec);
                        }
                        return;
                    }

                    List args;
                    args.append(value);

                    setterFunc->call(exec, this, args);
                    return;
                } else {
                    // If there's an existing property on the object or one of its
                    // prototype it should be replaced, so we just break here.
                    break;
                }
            }

            if (!JSValue::isObject(obj->_proto)) {
                break;
            }

            obj = static_cast<JSObject *>(obj->_proto);
        }
    }

    if (!isExtensible() && !_prop.get(propertyName)) {
        return;
    }
    _prop.put(propertyName, value, attr, checkRO);
}

void JSObject::put(ExecState *exec, unsigned propertyName,
                   JSValue *value, int attr)
{
    put(exec, Identifier::from(propertyName), value, attr);
}

// ECMA 8.6.2.3
bool JSObject::canPut(ExecState *, const Identifier &propertyName) const
{
    unsigned attributes;

    // Don't look in the prototype here. We can always put an override
    // in the object, even if the prototype has a ReadOnly property.

    if (!getPropertyAttributes(propertyName, attributes)) {
        return true;
    } else {
        return !(attributes & ReadOnly);
    }
}

// ECMA 8.6.2.4
bool JSObject::hasProperty(ExecState *exec, const Identifier &propertyName) const
{
    PropertySlot slot;
    return const_cast<JSObject *>(this)->getPropertySlot(exec, propertyName, slot);
}

bool JSObject::hasProperty(ExecState *exec, unsigned propertyName) const
{
    PropertySlot slot;
    return const_cast<JSObject *>(this)->getPropertySlot(exec, propertyName, slot);
}

// ECMA 8.6.2.5
bool JSObject::deleteProperty(ExecState * /*exec*/, const Identifier &propertyName)
{
    unsigned attributes;
    JSValue *v = _prop.get(propertyName, attributes);
    if (v) {
        if ((attributes & DontDelete)) {
            return false;
        }
        _prop.remove(propertyName);
        if (attributes & GetterSetter) {
            _prop.setHasGetterSetterProperties(_prop.containsGettersOrSetters());
        }
        return true;
    }

    // Look in the static hashtable of properties
    const HashEntry *entry = findPropertyHashEntry(propertyName);
    if (entry && entry->attr & DontDelete) {
        return false;    // this builtin property can't be deleted
    }
    return true;
}

bool JSObject::deleteProperty(ExecState *exec, unsigned propertyName)
{
    return deleteProperty(exec, Identifier::from(propertyName));
}

static ALWAYS_INLINE JSValue *tryGetAndCallProperty(ExecState *exec, const JSObject *object, const Identifier &propertyName)
{
    JSValue *v = object->get(exec, propertyName);
    if (JSValue::isObject(v)) {
        JSObject *o = static_cast<JSObject *>(v);
        if (o->implementsCall()) { // spec says "not primitive type" but ...
            JSObject *thisObj = const_cast<JSObject *>(object);
            JSValue *def = o->call(exec, thisObj, List::empty());
            JSType defType = JSValue::type(def);
            ASSERT(defType != GetterSetterType);
            if (defType != ObjectType) {
                return def;
            }
        }
    }
    return nullptr;
}

bool JSObject::getPrimitiveNumber(ExecState *exec, double &number, JSValue *&result)
{
    result = defaultValue(exec, NumberType);
    number = JSValue::toNumber(result, exec);
    return !JSValue::isString(result);
}

// ECMA 8.6.2.6
JSValue *JSObject::defaultValue(ExecState *exec, JSType hint) const
{
    const Identifier *firstPropertyName;
    const Identifier *secondPropertyName;
    /* Prefer String for Date objects */
    if ((hint == StringType) || ((hint != NumberType) && (_proto == exec->lexicalInterpreter()->builtinDatePrototype()))) {
        firstPropertyName = &exec->propertyNames().toString;
        secondPropertyName = &exec->propertyNames().valueOf;
    } else {
        firstPropertyName = &exec->propertyNames().valueOf;
        secondPropertyName = &exec->propertyNames().toString;
    }

    JSValue *v;
    if ((v = tryGetAndCallProperty(exec, this, *firstPropertyName))) {
        return v;
    }
    if ((v = tryGetAndCallProperty(exec, this, *secondPropertyName))) {
        return v;
    }

    if (exec->hadException()) {
        return exec->exception();
    }

    return throwError(exec, TypeError, "No default value");
}

const HashEntry *JSObject::findPropertyHashEntry(const Identifier &propertyName) const
{
    for (const ClassInfo *info = classInfo(); info; info = info->parentClass) {
        if (const HashTable *propHashTable = info->propHashTable) {
            if (const HashEntry *e = Lookup::findEntry(propHashTable, propertyName)) {
                return e;
            }
        }
    }
    return nullptr;
}

void JSObject::defineGetter(ExecState *, const Identifier &propertyName, JSObject *getterFunc)
{
    JSValue *o = getDirect(propertyName);
    GetterSetterImp *gs;

    if (o && JSValue::type(o) == GetterSetterType) {
        gs = static_cast<GetterSetterImp *>(o);
    } else {
        gs = new GetterSetterImp;
        putDirect(propertyName, gs, GetterSetter);
    }

    _prop.setHasGetterSetterProperties(true);
    gs->setGetter(getterFunc);
}

void JSObject::defineSetter(ExecState *, const Identifier &propertyName, JSObject *setterFunc)
{
    JSValue *o = getDirect(propertyName);
    GetterSetterImp *gs;

    if (o && JSValue::type(o) == GetterSetterType) {
        gs = static_cast<GetterSetterImp *>(o);
    } else {
        gs = new GetterSetterImp;
        putDirect(propertyName, gs, GetterSetter);
    }

    _prop.setHasGetterSetterProperties(true);
    gs->setSetter(setterFunc);
}

//ECMA Edition 5.1r6 - 8.12.9
bool JSObject::defineOwnProperty(ExecState *exec, const Identifier &propertyName, PropertyDescriptor &desc, bool shouldThrow)
{
    PropertyDescriptor current;

    // if Object does not have propertyName as OwnProperty just push it.
    if (!getOwnPropertyDescriptor(exec, propertyName, current)) {
        if (!isExtensible()) {
            if (shouldThrow) {
                throwError(exec, TypeError, "Object is not extensible \'" + propertyName.ustring() + "\'");
            }
            return false;
        }
        if (desc.isGenericDescriptor() || desc.isDataDescriptor()) {
            putDirect(propertyName, desc.value() ? desc.value() : jsUndefined(), desc.attributes());
        } else if (desc.isAccessorDescriptor()) {
            GetterSetterImp *gs = new GetterSetterImp();
            putDirect(propertyName, gs, desc.attributes() | GetterSetter);
            _prop.setHasGetterSetterProperties(true);
            if (desc.getter() && !JSValue::isUndefined(desc.getter())) {
                gs->setGetter(JSValue::toObject(desc.getter(), exec));
            }
            if (desc.setter() && !JSValue::isUndefined(desc.setter())) {
                gs->setSetter(JSValue::toObject(desc.setter(), exec));
            }
        }
        return true;
    }

    //Step 5
    if (desc.isEmpty()) {
        return true;
    }

    //Step 6
    if (desc.equalTo(exec, current)) {
        return true;
    }

    //Step 7
    // Filter out invalid unconfigurable configurations
    if (!current.configurable()) {
        if (desc.configurable()) {
            if (shouldThrow) {
                throwError(exec, TypeError, "can not redefine non-configurable property \'" + propertyName.ustring() + "\'");
            }
            return false;
        }
        if (desc.enumerableSet() && desc.enumerable() != current.enumerable()) {
            if (shouldThrow) {
                throwError(exec, TypeError, "can not change enumerable attribute of unconfigurable property \'" + propertyName.ustring() + "\'");
            }
            return false;
        }
    }

    //Step 8.
    if (!desc.isGenericDescriptor()) {
        if (current.isDataDescriptor() != desc.isDataDescriptor()) { // Step 9
            // DataDescriptor updating to AccessorDescriptor, or the other way.
            if (!current.configurable()) {
                if (shouldThrow) {
                    throwError(exec, TypeError, "can not change access mechanism for an unconfigurable property \'" + propertyName.ustring() + "\'");
                }
                return false;
            }

            deleteProperty(exec, propertyName);

            if (current.isDataDescriptor()) {
                // Updating from DataDescriptor to AccessorDescriptor
                GetterSetterImp *gs = new GetterSetterImp();
                putDirect(propertyName, gs, current.attributesWithOverride(desc) | GetterSetter);
                _prop.setHasGetterSetterProperties(true);

                if (desc.getter()) {
                    if (JSValue::isUndefined(desc.getter())) {
                        gs->setGetter(nullptr);
                    } else {
                        gs->setGetter(JSValue::toObject(desc.getter(), exec));
                    }
                }
                if (desc.setter()) {
                    if (JSValue::isUndefined(desc.setter())) {
                        gs->setSetter(nullptr);
                    } else {
                        gs->setSetter(JSValue::toObject(desc.setter(), exec));
                    }
                }
            } else {
                // Updating from AccessorDescriptor to DataDescriptor
                unsigned int newAttr = current.attributesWithOverride(desc);
                if (!desc.writable()) {
                    newAttr |= ReadOnly;
                }
                putDirect(propertyName, desc.value() ? desc.value() : jsUndefined(), newAttr);
            }
            return true;
        } else if (current.isDataDescriptor() && desc.isDataDescriptor()) { //Step 10
            // Just updating the value here
            if (!current.configurable()) {
                if (!current.writable() && desc.writable()) {
                    if (shouldThrow) {
                        throwError(exec, TypeError, "can not change writable attribute of unconfigurable property \'" + propertyName.ustring() + "\'");
                    }
                    return false;
                }
                if (!current.writable()) {
                    if (desc.value() && !(current.value() && sameValue(exec, current.value(), desc.value()))) {
                        if (shouldThrow) {
                            throwError(exec, TypeError, "can not change value of a readonly property \'" + propertyName.ustring() + "\'");
                        }
                        return false;
                    }
                }
            } else {
                if (!deleteProperty(exec, propertyName)) {
                    removeDirect(propertyName);
                }

                putDirect(propertyName, desc.value() ? desc.value() : current.value(), current.attributesWithOverride(desc));
                return true;
            }
        } else if (current.isAccessorDescriptor() && desc.isAccessorDescriptor()) { // Step 11
            // Filter out unconfigurable combinations
            if (!current.configurable()) {
                if (desc.setter() && !sameValue(exec, desc.setter(), current.setter() ? current.setter() : jsUndefined())) {
                    if (shouldThrow) {
                        throwError(exec, TypeError, "can not change the setter of an unconfigurable property \'" + propertyName.ustring() + "\'");
                    }
                    return false;
                }
                if (desc.getter() && !sameValue(exec, desc.getter(), current.getter() ? current.getter() : jsUndefined())) {
                    if (shouldThrow) {
                        throwError(exec, TypeError, "can not change the getter of an unconfigurable property \'" + propertyName.ustring() + "\'");
                    }
                    return false;
                }
            }
        }
    }

    //Step 12
    // Everything is allowed here, updating GetterSetter, storing new value
    JSValue *jsval = getDirect(propertyName);
    unsigned int newAttr = current.attributesWithOverride(desc);
    if (jsval && JSValue::type(jsval) == GetterSetterType) {
        GetterSetterImp *gs = static_cast<GetterSetterImp *>(jsval);
        if (desc.getter()) {
            if (JSValue::isUndefined(desc.getter())) {
                gs->setGetter(nullptr);
            } else {
                gs->setGetter(JSValue::toObject(desc.getter(), exec));
            }
        }
        if (desc.setter()) {
            if (JSValue::isUndefined(desc.setter())) {
                gs->setSetter(nullptr);
            } else {
                gs->setSetter(JSValue::toObject(desc.setter(), exec));
            }
        }
    } else {
        jsval = desc.value() ? desc.value() : current.value();
    }

    deleteProperty(exec, propertyName);
    if (JSValue::type(jsval) == GetterSetterType) {
        putDirect(propertyName, jsval, newAttr | GetterSetter);
        _prop.setHasGetterSetterProperties(true);
    } else {
        put(exec, propertyName, jsval, newAttr);
    }

    return true; //Step 13
}

void JSObject::preventExtensions()
{
    if (isExtensible()) {
        _prop.setExtensible(false);
    }
}

bool JSObject::implementsConstruct() const
{
    return false;
}

JSObject *JSObject::construct(ExecState *, const List & /*args*/)
{
    assert(false);
    return nullptr;
}

JSObject *JSObject::construct(ExecState *exec, const List &args, const Identifier & /*functionName*/, const UString & /*sourceURL*/, int /*lineNumber*/)
{
    return construct(exec, args);
}

JSObject *JSObject::valueClone(Interpreter * /*targetCtx*/) const
{
    return nullptr;
}

bool JSObject::isFunctionType() const
{
    return implementsCall();
}

JSValue *JSObject::callAsFunction(ExecState * /*exec*/, JSObject * /*thisObj*/, const List &/*args*/)
{
    assert(false);
    return nullptr;
}

bool JSObject::implementsHasInstance() const
{
    return false;
}

bool JSObject::hasInstance(ExecState *exec, JSValue *value)
{
    JSValue *proto = get(exec, exec->propertyNames().prototype);
    if (!JSValue::isObject(proto)) {
        throwError(exec, TypeError, "instanceof called on an object with an invalid prototype property.");
        return false;
    }

    if (!JSValue::isObject(value)) {
        return false;
    }

    JSObject *o = static_cast<JSObject *>(value);
    while ((o = JSValue::getObject(o->prototype()))) {
        if (o == proto) {
            return true;
        }
    }
    return false;
}

bool JSObject::propertyIsEnumerable(ExecState *, const Identifier &propertyName) const
{
    unsigned attributes;

    if (!getPropertyAttributes(propertyName, attributes)) {
        return false;
    } else {
        return !(attributes & DontEnum);
    }
}

bool JSObject::getPropertyAttributes(const Identifier &propertyName, unsigned &attributes) const
{
    if (_prop.get(propertyName, attributes)) {
        return true;
    }

    // Look in the static hashtable of properties
    const HashEntry *e = findPropertyHashEntry(propertyName);
    if (e) {
        attributes = e->attr;
        return true;
    }

    return false;
}

void JSObject::getOwnPropertyNames(ExecState * /*exec*/, PropertyNameArray &propertyNames, PropertyMap::PropertyMode mode)
{
    _prop.getPropertyNames(propertyNames, mode);

    // Add properties from the static hashtable of properties
    const ClassInfo *info = classInfo();
    while (info) {
        if (info->propHashTable) {
            int size = info->propHashTable->size;
            const HashEntry *e = info->propHashTable->entries;
            for (int i = 0; i < size; ++i, ++e) {
                if (e->s && PropertyMap::checkEnumerable(e->attr, mode)) {
                    propertyNames.add(e->s);
                }
            }
        }
        info = info->parentClass;
    }
}

bool JSObject::toBoolean(ExecState * /*exec*/) const
{
    return true;
}

double JSObject::toNumber(ExecState *exec) const
{
    JSValue *prim = toPrimitive(exec, NumberType);
    if (exec->hadException()) { // should be picked up soon in nodes.cpp
        return 0.0;
    }
    return JSValue::toNumber(prim, exec);
}

UString JSObject::toString(ExecState *exec) const
{
    JSValue *prim = toPrimitive(exec, StringType);
    if (exec->hadException()) { // should be picked up soon in nodes.cpp
        return UString(UString::empty);
    }
    return JSValue::toString(prim, exec);
}

JSObject *JSObject::toObject(ExecState * /*exec*/) const
{
    return const_cast<JSObject *>(this);
}

void JSObject::putDirect(const Identifier &propertyName, int value, int attr)
{
    _prop.put(propertyName, jsNumber(value), attr);
}

void JSObject::removeDirect(const Identifier &propertyName)
{
    _prop.remove(propertyName);
}

void JSObject::putDirectFunction(InternalFunctionImp *func, int attr)
{
    putDirect(func->functionName(), func, attr);
}

void JSObject::fillGetterPropertySlot(PropertySlot &slot, JSValue **location)
{
    GetterSetterImp *gs = static_cast<GetterSetterImp *>(*location);
    JSObject *getterFunc = gs->getGetter();
    if (getterFunc) {
        slot.setGetterSlot(this, getterFunc);
    } else {
        slot.setUndefined(this);
    }
}

// ------------------------------ Error ----------------------------------------

const char *const errorNamesArr[] = {
    I18N_NOOP("Error"), // GeneralError
    I18N_NOOP("Evaluation error"), // EvalError
    I18N_NOOP("Range error"), // RangeError
    I18N_NOOP("Reference error"), // ReferenceError
    I18N_NOOP("Syntax error"), // SyntaxError
    I18N_NOOP("Type error"), // TypeError
    I18N_NOOP("URI error"), // URIError
};

const char *const *const Error::errorNames = errorNamesArr;

JSObject *Error::create(ExecState *exec, ErrorType errtype, const UString &message,
                        int lineno, int sourceId, const UString &sourceURL)
{
#ifdef KJS_VERBOSE
    // message could be 0L. Don't enable this on Solaris ;)
    fprintf(stderr, "WARNING: KJS %s: %s\n", errorNamesArr[errtype], message.ascii());
#endif

    Interpreter *interp = exec->lexicalInterpreter();
    JSObject *cons;
    switch (errtype) {
    case EvalError:
        cons = interp->builtinEvalError();
        break;
    case RangeError:
        cons = interp->builtinRangeError();
        break;
    case ReferenceError:
        cons = interp->builtinReferenceError();
        break;
    case SyntaxError:
        cons = interp->builtinSyntaxError();
        break;
    case TypeError:
        cons = interp->builtinTypeError();
        break;
    case URIError:
        cons = interp->builtinURIError();
        break;
    default:
        cons = interp->builtinError();
        break;
    }

    List args;
    if (message.isEmpty()) {
        args.append(jsString(errorNames[errtype]));
    } else {
        args.append(jsString(message));
    }
    JSObject *err = static_cast<JSObject *>(cons->construct(exec, args));

    if (lineno != -1) {
        err->put(exec, "line", jsNumber(lineno));
    }
    if (sourceId != -1) {
        err->put(exec, "sourceId", jsNumber(sourceId));
    }

    if (!sourceURL.isNull()) {
        err->put(exec, "sourceURL", jsString(sourceURL));
    }

    return err;

    /*
    #ifndef NDEBUG
      const char *msg = err->get(messagePropertyName)->toString().value().ascii();
      if (l >= 0)
          fprintf(stderr, "KJS: %s at line %d. %s\n", estr, l, msg);
      else
          fprintf(stderr, "KJS: %s. %s\n", estr, msg);
    #endif

      return err;
    */
}

JSObject *Error::create(ExecState *exec, ErrorType type, const char *message)
{
    return create(exec, type, message, -1, -1, nullptr);
}

JSObject *throwError(ExecState *exec, ErrorType type)
{
    JSObject *error = Error::create(exec, type, UString(), -1, -1, nullptr);
    exec->setException(error);
    return error;
}

JSObject *throwError(ExecState *exec, ErrorType type, const UString &message)
{
    JSObject *error = Error::create(exec, type, message, -1, -1, nullptr);
    exec->setException(error);
    return error;
}

JSObject *throwError(ExecState *exec, ErrorType type, const char *message)
{
    JSObject *error = Error::create(exec, type, message, -1, -1, nullptr);
    exec->setException(error);
    return error;
}

JSObject *throwError(ExecState *exec, ErrorType type, const UString &message, int line, int sourceId, const UString &sourceURL)
{
    JSObject *error = Error::create(exec, type, message, line, sourceId, sourceURL);
    exec->setException(error);
    return error;
}

} // namespace KJS