JavaScriptCore/kjs/JSNotAnObject.h

/*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

#ifndef JSNotAnObject_h
#define JSNotAnObject_h

#include "JSObject.h"

namespace JSC {

    class JSNotAnObjectErrorStub : public JSObject {
    public:
        JSNotAnObjectErrorStub(ExecState* exec, bool isNull)
            : JSObject(exec->globalData().nullProtoStructureID)
            , m_isNull(isNull)
        {
        }
        bool isNull() const { return m_isNull; }
        bool isNotAnObjectErrorStub() const { return true; }
    private:
        bool m_isNull;
    };
    
    // This unholy class is used to allow us to avoid multiple exception checks
    // in certain SquirrelFish opcodes -- effectively it just silently consumes
    // any operations performed on the result of a failed toObject call.
    class JSNotAnObject : public JSObject {
    public:
        JSNotAnObject(ExecState* exec, JSNotAnObjectErrorStub* exception)
            : JSObject(exec->globalData().nullProtoStructureID)
            , m_exception(exception)
        {
        }

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

        // Marking
        virtual void mark();

        // JSObject methods
        virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
        virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);

        virtual void put(ExecState*, const Identifier& propertyName, JSValue*, PutPropertySlot&);
        virtual void put(ExecState*, unsigned propertyName, JSValue*);

        virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
        virtual bool deleteProperty(ExecState*, unsigned propertyName);

        virtual void getPropertyNames(ExecState*, PropertyNameArray&);

        JSNotAnObjectErrorStub* m_exception;
    };

} // namespace JSC

#endif // JSNotAnObject_h