src/third_party/WebKit/Source/JavaScriptCore/runtime/JSNotAnObject.h

/*
 * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 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
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef JSNotAnObject_h
#define JSNotAnObject_h

#include "JSObject.h"

namespace JSC {

    // This unholy class is used to allow us to avoid multiple exception checks
    // in certain SquirrelFish bytecodes -- effectively it just silently consumes
    // any operations performed on the result of a failed toObject call.
    class JSNotAnObject : public JSNonFinalObject {
    private:
        JSNotAnObject(ExecState* exec)
            : JSNonFinalObject(exec->globalData(), exec->globalData().notAnObjectStructure.get())
        {
        }
        
    public:
        typedef JSNonFinalObject Base;

        static JSNotAnObject* create(ExecState* exec)
        {
            JSNotAnObject* object = new (NotNull, allocateCell<JSNotAnObject>(*exec->heap())) JSNotAnObject(exec);
            object->finishCreation(exec->globalData());
            return object;
        }

        static Structure* createStructure(JSGlobalData& globalData, JSGlobalObject* globalObject, JSValue prototype)
        {
            return Structure::create(globalData, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), &s_info);
        }

        DECLARE_CLASSINFO();

     private:
        
        static const unsigned StructureFlags = OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesGetPropertyNames | JSObject::StructureFlags;

        // JSValue methods
        static JSValue defaultValue(const JSObject*, ExecState*, PreferredPrimitiveType);

        // JSObject methods
        static bool getOwnPropertySlot(JSCell*, ExecState*, PropertyName, PropertySlot&);
        static bool getOwnPropertySlotByIndex(JSCell*, ExecState*, unsigned propertyName, PropertySlot&);
        static bool getOwnPropertyDescriptor(JSObject*, ExecState*, PropertyName, PropertyDescriptor&);

        static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
        static void putByIndex(JSCell*, ExecState*, unsigned propertyName, JSValue, bool shouldThrow);

        static bool deleteProperty(JSCell*, ExecState*, PropertyName);
        static bool deletePropertyByIndex(JSCell*, ExecState*, unsigned propertyName);

        static void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
    };

} // namespace JSC

#endif // JSNotAnObject_h