Source/bindings/v8/V8DOMWrapper.h

/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 *
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef V8DOMWrapper_h
#define V8DOMWrapper_h

#include "bindings/v8/DOMDataStore.h"
#include <v8.h>
#include "wtf/PassRefPtr.h"
#include "wtf/RawPtr.h"
#include "wtf/text/AtomicString.h"

namespace WebCore {

struct WrapperTypeInfo;

    class V8DOMWrapper {
    public:
        static v8::Local<v8::Object> createWrapper(v8::Handle<v8::Object> creationContext, const WrapperTypeInfo*, void*, v8::Isolate*);

        template<typename V8T, typename T>
        static inline v8::Handle<v8::Object> associateObjectWithWrapper(PassRefPtr<T>, const WrapperTypeInfo*, v8::Handle<v8::Object>, v8::Isolate*, WrapperConfiguration::Lifetime);
        template<typename V8T, typename T>
        static inline v8::Handle<v8::Object> associateObjectWithWrapper(RawPtr<T> object, const WrapperTypeInfo* type, v8::Handle<v8::Object> wrapper, v8::Isolate* isolate, WrapperConfiguration::Lifetime lifetime) { return associateObjectWithWrapper<V8T, T>(object.get(), type, wrapper, isolate, lifetime); }
        template<typename V8T, typename T>
        static inline v8::Handle<v8::Object> associateObjectWithWrapper(T*, const WrapperTypeInfo*, v8::Handle<v8::Object>, v8::Isolate*, WrapperConfiguration::Lifetime);
        static inline void setNativeInfo(v8::Handle<v8::Object>, const WrapperTypeInfo*, void*);
        static inline void setNativeInfoForHiddenWrapper(v8::Handle<v8::Object>, const WrapperTypeInfo*, void*);
        static inline void setNativeInfoWithPersistentHandle(v8::Handle<v8::Object>, const WrapperTypeInfo*, void*, PersistentNode*);
        static inline void clearNativeInfo(v8::Handle<v8::Object>, const WrapperTypeInfo*);

        static bool isDOMWrapper(v8::Handle<v8::Value>);
    };

    inline void V8DOMWrapper::setNativeInfo(v8::Handle<v8::Object> wrapper, const WrapperTypeInfo* type, void* object)
    {
        ASSERT(wrapper->InternalFieldCount() >= 2);
        ASSERT(object);
        ASSERT(type);
#if ENABLE(OILPAN)
        ASSERT(!type->isGarbageCollected);
#endif
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperObjectIndex, object);
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperTypeIndex, const_cast<WrapperTypeInfo*>(type));
    }

    inline void V8DOMWrapper::setNativeInfoForHiddenWrapper(v8::Handle<v8::Object> wrapper, const WrapperTypeInfo* type, void* object)
    {
        // see V8WindowShell::installDOMWindow() comment for why this version is needed and safe.
        ASSERT(wrapper->InternalFieldCount() >= 2);
        ASSERT(object);
        ASSERT(type);
#if ENABLE(OILPAN)
        ASSERT(type->isGarbageCollected);
#endif
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperObjectIndex, object);
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperTypeIndex, const_cast<WrapperTypeInfo*>(type));
        // Clear out the last internal field, which is assumed to contain a valid persistent pointer value.
        wrapper->SetAlignedPointerInInternalField(wrapper->InternalFieldCount() - 1, 0);
    }


    inline void V8DOMWrapper::setNativeInfoWithPersistentHandle(v8::Handle<v8::Object> wrapper, const WrapperTypeInfo* type, void* object, PersistentNode* handle)
    {
        ASSERT(wrapper->InternalFieldCount() >= 3);
        ASSERT(object);
        ASSERT(type);
        ASSERT(type->isGarbageCollected);
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperObjectIndex, object);
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperTypeIndex, const_cast<WrapperTypeInfo*>(type));
        // Persistent handle is stored in the last internal field.
        wrapper->SetAlignedPointerInInternalField(wrapper->InternalFieldCount() - 1, handle);
    }

    inline void V8DOMWrapper::clearNativeInfo(v8::Handle<v8::Object> wrapper, const WrapperTypeInfo* type)
    {
        ASSERT(wrapper->InternalFieldCount() >= 2);
        ASSERT(type);
        // clearNativeInfo() is used only by NP objects, which are not garbage collected.
        ASSERT(!type->isGarbageCollected);
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperTypeIndex, const_cast<WrapperTypeInfo*>(type));
        wrapper->SetAlignedPointerInInternalField(v8DOMWrapperObjectIndex, 0);
    }

    template<typename V8T, typename T>
    inline v8::Handle<v8::Object> V8DOMWrapper::associateObjectWithWrapper(PassRefPtr<T> object, const WrapperTypeInfo* type, v8::Handle<v8::Object> wrapper, v8::Isolate* isolate, WrapperConfiguration::Lifetime lifetime)
    {
        setNativeInfo(wrapper, type, V8T::toInternalPointer(object.get()));
        ASSERT(isDOMWrapper(wrapper));
        WrapperConfiguration configuration = buildWrapperConfiguration(object.get(), lifetime);
        DOMDataStore::setWrapper<V8T>(object.leakRef(), wrapper, isolate, configuration);
        return wrapper;
    }

    template<typename V8T, typename T>
    inline v8::Handle<v8::Object> V8DOMWrapper::associateObjectWithWrapper(T* object, const WrapperTypeInfo* type, v8::Handle<v8::Object> wrapper, v8::Isolate* isolate, WrapperConfiguration::Lifetime lifetime)
    {
        setNativeInfoWithPersistentHandle(wrapper, type, V8T::toInternalPointer(object), new Persistent<T>(object));
        ASSERT(isDOMWrapper(wrapper));
        WrapperConfiguration configuration = buildWrapperConfiguration(object, lifetime);
        DOMDataStore::setWrapper<V8T>(object, wrapper, isolate, configuration);
        return wrapper;
    }

    class V8WrapperInstantiationScope {
    public:
        V8WrapperInstantiationScope(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
            : m_didEnterContext(false)
            , m_context(isolate->GetCurrentContext())
        {
            // FIXME: Remove all empty creationContexts from caller sites.
            // If a creationContext is empty, we will end up creating a new object
            // in the context currently entered. This is wrong.
            if (creationContext.IsEmpty())
                return;
            v8::Handle<v8::Context> contextForWrapper = creationContext->CreationContext();
            // For performance, we enter the context only if the currently running context
            // is different from the context that we are about to enter.
            if (contextForWrapper == m_context)
                return;
            m_context = v8::Local<v8::Context>::New(isolate, contextForWrapper);
            m_didEnterContext = true;
            m_context->Enter();
        }

        ~V8WrapperInstantiationScope()
        {
            if (!m_didEnterContext)
                return;
            m_context->Exit();
        }

        v8::Handle<v8::Context> context() const { return m_context; }

    private:
        bool m_didEnterContext;
        v8::Handle<v8::Context> m_context;
    };

}

#endif // V8DOMWrapper_h