WrapperTypeInfo.h   [plain text]

/*
 * Copyright (C) 2010 Google 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 are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 */

#ifndef WrapperTypeInfo_h
#define WrapperTypeInfo_h

#include <v8.h>

namespace WebCore {
    
    class ActiveDOMObject;
    
    static const int v8DOMWrapperTypeIndex = 0;
    static const int v8DOMWrapperObjectIndex = 1;
    static const int v8DefaultWrapperInternalFieldCount = 2;

    static const uint16_t v8DOMSubtreeClassId = 1;

    typedef v8::Persistent<v8::FunctionTemplate> (*GetTemplateFunction)();
    typedef void (*DerefObjectFunction)(void*);
    typedef ActiveDOMObject* (*ToActiveDOMObjectFunction)(v8::Handle<v8::Object>);
    
    // This struct provides a way to store a bunch of information that is helpful when unwrapping
    // v8 objects. Each v8 bindings class has exactly one static WrapperTypeInfo member, so
    // comparing pointers is a safe way to determine if types match.
    struct WrapperTypeInfo {
        
        static WrapperTypeInfo* unwrap(v8::Handle<v8::Value> typeInfoWrapper)
        {
            return reinterpret_cast<WrapperTypeInfo*>(v8::External::Unwrap(typeInfoWrapper));
        }
        
        
        bool equals(const WrapperTypeInfo* that) const
        {
            return this == that;
        }

        bool isSubclass(const WrapperTypeInfo* that) const
        {
            for (const WrapperTypeInfo* current = this; current; current = current->parentClass) {
                if (current == that)
                    return true;
            }

            return false;
        }
        
        v8::Persistent<v8::FunctionTemplate> getTemplate() { return getTemplateFunction(); }
        
        void derefObject(void* object)
        {
            if (derefObjectFunction) 
                derefObjectFunction(object);
        }
        
        ActiveDOMObject* toActiveDOMObject(v8::Handle<v8::Object> object)
        {
            if (!toActiveDOMObjectFunction)
                return 0;
            return toActiveDOMObjectFunction(object);
        }
        
        const GetTemplateFunction getTemplateFunction;
        const DerefObjectFunction derefObjectFunction;
        const ToActiveDOMObjectFunction toActiveDOMObjectFunction;
        const WrapperTypeInfo* parentClass;
    };
}

#endif // WrapperTypeInfo_h