JavaScriptCore/kjs/JSString.h

/*
 *  Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
 *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 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.
 *
 */

#ifndef JSString_h
#define JSString_h

#include "CommonIdentifiers.h"
#include "ExecState.h"
#include "JSCell.h"
#include "JSNumberCell.h"
#include "PropertySlot.h"
#include "identifier.h"
#include "ustring.h"

namespace KJS {

    class JSString : public JSCell {
    public:
        JSString(const UString& value)
            : m_value(value)
        {
            Heap::heap(this)->reportExtraMemoryCost(value.cost());
        }

        enum HasOtherOwnerType { HasOtherOwner };
        JSString(const UString& value, HasOtherOwnerType)
            : m_value(value)
        {
        }

        const UString& value() const { return m_value; }

        bool getStringPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
        bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);

        bool canGetIndex(unsigned i) { return i < static_cast<unsigned>(m_value.size()); }
        JSValue* getIndex(ExecState* exec, unsigned i)
        {
            ASSERT(canGetIndex(i));
            return new (exec) JSString(m_value.substr(i, 1));
        }

    private:
        virtual bool isString() const;

        virtual JSValue* toPrimitive(ExecState*, PreferredPrimitiveType) const;
        virtual bool getPrimitiveNumber(ExecState*, double& number, JSValue*& value);
        virtual bool toBoolean(ExecState*) const;
        virtual double toNumber(ExecState*) const;
        virtual JSObject* toObject(ExecState*) const;
        virtual UString toString(ExecState*) const;

        virtual JSObject* toThisObject(ExecState*) const;
        virtual UString toThisString(ExecState*) const;
        virtual JSString* toThisJSString(ExecState*);

        // Actually getPropertySlot, not getOwnPropertySlot (see JSCell).
        virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
        virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);

        UString m_value;
    };

    JSString* jsString(ExecState*, const UString&); // returns empty string if passed null string
    JSString* jsString(ExecState*, const char* = ""); // returns empty string if passed 0

    // Should be used for strings that are owned by an object that will
    // likely outlive the JSValue this makes, such as the parse tree or a
    // DOM object that contains a UString
    JSString* jsOwnedString(ExecState*, const UString&); 

    ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
    {
        if (propertyName == exec->propertyNames().length) {
            slot.setValue(jsNumber(exec, value().size()));
            return true;
        }

        bool isStrictUInt32;
        unsigned i = propertyName.toStrictUInt32(&isStrictUInt32);
        if (isStrictUInt32 && i < static_cast<unsigned>(m_value.size())) {
            slot.setValue(jsString(exec, value().substr(i, 1)));
            return true;
        }

        return false;
    }
        
    ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
    {
        if (propertyName < static_cast<unsigned>(m_value.size())) {
            slot.setValue(jsString(exec, value().substr(propertyName, 1)));
            return true;
        }

        return false;
    }

    // --- JSValue inlines ----------------------------

    inline JSString* JSValue::toThisJSString(ExecState* exec)
    {
        return JSImmediate::isImmediate(this) ? jsString(exec, JSImmediate::toString(this)) : asCell()->toThisJSString(exec);
    }

} // namespace KJS

#endif // JSString_h