runtime/JSNotAnObject.h

   1 /*
   2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef JSNotAnObject_h
  30 #define JSNotAnObject_h
  31
  32 #include "JSObject.h"
  33
  34 namespace JSC {
  35
  36     // This unholy class is used to allow us to avoid multiple exception checks
  37     // in certain SquirrelFish bytecodes -- effectively it just silently consumes
  38     // any operations performed on the result of a failed toObject call.
  39     class JSNotAnObject : public JSNonFinalObject {
  40     public:
  41         JSNotAnObject(ExecState* exec)
  42             : JSNonFinalObject(exec->globalData(), exec->globalData().notAnObjectStructure.get())
  43         {
  44         }
  45
  46         static Structure* createStructure(JSGlobalData& globalData, JSValue prototype)
  47         {
  48             return Structure::create(globalData, prototype, TypeInfo(ObjectType, StructureFlags), AnonymousSlotCount, &s_info);
  49         }
  50
  51      private:
  52
  53         static const unsigned StructureFlags = OverridesGetOwnPropertySlot | OverridesGetPropertyNames | JSObject::StructureFlags;
  54
  55         // JSValue methods
  56         virtual JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
  57         virtual bool getPrimitiveNumber(ExecState*, double& number, JSValue&);
  58         virtual bool toBoolean(ExecState*) const;
  59         virtual double toNumber(ExecState*) const;
  60         virtual UString toString(ExecState*) const;
  61         virtual JSObject* toObject(ExecState*, JSGlobalObject*) const;
  62
  63         // JSObject methods
  64         virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
  65         virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
  66         virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
  67
  68         virtual void put(ExecState*, const Identifier& propertyName, JSValue, PutPropertySlot&);
  69         virtual void put(ExecState*, unsigned propertyName, JSValue);
  70
  71         virtual bool deleteProperty(ExecState*, const Identifier& propertyName);
  72         virtual bool deleteProperty(ExecState*, unsigned propertyName);
  73
  74         virtual void getOwnPropertyNames(ExecState*, PropertyNameArray&, EnumerationMode mode = ExcludeDontEnumProperties);
  75     };
  76
  77 } // namespace JSC
  78
  79 #endif // JSNotAnObject_h