Source/JavaScriptCore/runtime/Operations.cpp

/*
 * Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
 * Copyright (C) 2008, 2016 Apple Inc. All Rights Reserved.
 *
 *  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 "config.h"
#include "Operations.h"

#include "Error.h"
#include "JSBigInt.h"
#include "JSCInlines.h"
#include "JSObject.h"
#include "JSString.h"
#include <wtf/MathExtras.h>

namespace JSC {

bool JSValue::equalSlowCase(JSGlobalObject* globalObject, JSValue v1, JSValue v2)
{
    return equalSlowCaseInline(globalObject, v1, v2);
}

bool JSValue::strictEqualSlowCase(JSGlobalObject* globalObject, JSValue v1, JSValue v2)
{
    return strictEqualSlowCaseInline(globalObject, v1, v2);
}

NEVER_INLINE JSValue jsAddSlowCase(JSGlobalObject* globalObject, JSValue v1, JSValue v2)
{
    // exception for the Date exception in defaultValue()
    VM& vm = globalObject->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    JSValue p1 = v1.toPrimitive(globalObject);
    RETURN_IF_EXCEPTION(scope, { });
    JSValue p2 = v2.toPrimitive(globalObject);
    RETURN_IF_EXCEPTION(scope, { });

    if (p1.isString()) {
        if (p2.isCell()) {
            JSString* p2String = p2.toString(globalObject);
            RETURN_IF_EXCEPTION(scope, { });
            RELEASE_AND_RETURN(scope, jsString(globalObject, asString(p1), p2String));
        }
        String p2String = p2.toWTFString(globalObject);
        RETURN_IF_EXCEPTION(scope, { });
        RELEASE_AND_RETURN(scope, jsString(globalObject, asString(p1), p2String));
    }

    if (p2.isString()) {
        if (p1.isCell()) {
            JSString* p1String = p1.toString(globalObject);
            RETURN_IF_EXCEPTION(scope, { });
            RELEASE_AND_RETURN(scope, jsString(globalObject, p1String, asString(p2)));
        }
        String p1String = p1.toWTFString(globalObject);
        RETURN_IF_EXCEPTION(scope, { });
        RELEASE_AND_RETURN(scope, jsString(globalObject, p1String, asString(p2)));
    }

    auto leftNumeric = p1.toNumeric(globalObject);
    RETURN_IF_EXCEPTION(scope, { });
    auto rightNumeric = p2.toNumeric(globalObject);
    RETURN_IF_EXCEPTION(scope, { });

    if (WTF::holds_alternative<JSBigInt*>(leftNumeric) || WTF::holds_alternative<JSBigInt*>(rightNumeric)) {
        if (WTF::holds_alternative<JSBigInt*>(leftNumeric) && WTF::holds_alternative<JSBigInt*>(rightNumeric)) {
            scope.release();
            return JSBigInt::add(globalObject, WTF::get<JSBigInt*>(leftNumeric), WTF::get<JSBigInt*>(rightNumeric));
        }

        return throwTypeError(globalObject, scope, "Invalid mix of BigInt and other type in addition."_s);
    }

    return jsNumber(WTF::get<double>(leftNumeric) + WTF::get<double>(rightNumeric));
}

JSValue jsTypeStringForValue(VM& vm, JSGlobalObject* globalObject, JSValue v)
{
    if (v.isUndefined())
        return vm.smallStrings.undefinedString();
    if (v.isBoolean())
        return vm.smallStrings.booleanString();
    if (v.isNumber())
        return vm.smallStrings.numberString();
    if (v.isString())
        return vm.smallStrings.stringString();
    if (v.isSymbol())
        return vm.smallStrings.symbolString();
    if (v.isBigInt())
        return vm.smallStrings.bigintString();
    if (v.isObject()) {
        JSObject* object = asObject(v);
        // Return "undefined" for objects that should be treated
        // as null when doing comparisons.
        if (object->structure(vm)->masqueradesAsUndefined(globalObject))
            return vm.smallStrings.undefinedString();
        if (object->isFunction(vm))
            return vm.smallStrings.functionString();
    }
    return vm.smallStrings.objectString();
}

JSValue jsTypeStringForValue(JSGlobalObject* globalObject, JSValue v)
{
    return jsTypeStringForValue(globalObject->vm(), globalObject, v);
}

bool jsIsObjectTypeOrNull(JSGlobalObject* globalObject, JSValue v)
{
    VM& vm = globalObject->vm();
    if (!v.isCell())
        return v.isNull();

    JSType type = v.asCell()->type();
    if (type == StringType || type == SymbolType || type == BigIntType)
        return false;
    if (type >= ObjectType) {
        if (asObject(v)->structure(vm)->masqueradesAsUndefined(globalObject))
            return false;
        JSObject* object = asObject(v);
        if (object->isFunction(vm))
            return false;
    }
    return true;
}

size_t normalizePrototypeChain(JSGlobalObject* globalObject, JSCell* base, bool& sawPolyProto)
{
    VM& vm = globalObject->vm();
    size_t count = 0;
    sawPolyProto = false;
    JSCell* current = base;
    while (1) {
        Structure* structure = current->structure(vm);
        if (structure->isProxy())
            return InvalidPrototypeChain;

        sawPolyProto |= structure->hasPolyProto();

        JSValue prototype = structure->prototypeForLookup(globalObject, current);
        if (prototype.isNull())
            return count;

        current = prototype.asCell();
        structure = current->structure(vm);
        if (structure->isDictionary()) {
            if (structure->hasBeenFlattenedBefore())
                return InvalidPrototypeChain;
            structure->flattenDictionaryStructure(vm, asObject(current));
        }

        ++count;
    }
}

} // namespace JSC