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 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     private:
  41         explicit JSNotAnObject(VM& vm)
  42             : JSNonFinalObject(vm, vm.notAnObjectStructure.get())
  43         {
  44         }
  45
  46     public:
  47         typedef JSNonFinalObject Base;
  48
  49         static JSNotAnObject* create(VM& vm)
  50         {
  51             JSNotAnObject* object = new (NotNull, allocateCell<JSNotAnObject>(vm.heap)) JSNotAnObject(vm);
  52             object->finishCreation(vm);
  53             return object;
  54         }
  55
  56         static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
  57         {
  58             return Structure::create(vm, globalObject, prototype, TypeInfo(ObjectType, StructureFlags), info());
  59         }
  60
  61         DECLARE_INFO;
  62
  63      private:
  64
  65         static const unsigned StructureFlags = OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | OverridesGetPropertyNames | JSObject::StructureFlags;
  66
  67         // JSValue methods
  68         static JSValue defaultValue(const JSObject*, ExecState*, PreferredPrimitiveType);
  69
  70         // JSObject methods
  71         static bool getOwnPropertySlot(JSObject*, ExecState*, PropertyName, PropertySlot&);
  72         static bool getOwnPropertySlotByIndex(JSObject*, ExecState*, unsigned propertyName, PropertySlot&);
  73
  74         static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
  75         static void putByIndex(JSCell*, ExecState*, unsigned propertyName, JSValue, bool shouldThrow);
  76
  77         static bool deleteProperty(JSCell*, ExecState*, PropertyName);
  78         static bool deletePropertyByIndex(JSCell*, ExecState*, unsigned propertyName);
  79
  80         static void getOwnPropertyNames(JSObject*, ExecState*, PropertyNameArray&, EnumerationMode);
  81     };
  82
  83 } // namespace JSC
  84
  85 #endif // JSNotAnObject_h