Source/bindings/v8/V8PerContextData.h

/*
 * Copyright (C) 2012 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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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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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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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 */

#ifndef V8PerContextData_h
#define V8PerContextData_h

#include "bindings/v8/CustomElementBinding.h"
#include "bindings/v8/ScopedPersistent.h"
#include "bindings/v8/UnsafePersistent.h"
#include "bindings/v8/V8DOMActivityLogger.h"
#include "bindings/v8/WrapperTypeInfo.h"
#include <v8.h>
#include "wtf/HashMap.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/Vector.h"
#include "wtf/text/AtomicString.h"
#include "wtf/text/AtomicStringHash.h"

namespace WebCore {

class CustomElementDefinition;
struct V8NPObject;
typedef WTF::Vector<V8NPObject*> V8NPObjectVector;
typedef WTF::HashMap<int, V8NPObjectVector> V8NPObjectMap;

enum V8ContextEmbedderDataField {
    v8ContextDebugIdIndex,
    v8ContextPerContextDataIndex,
    v8ContextIsolatedWorld,
    // Rather than adding more embedder data fields to v8::Context,
    // consider adding the data to V8PerContextData instead.
};

class V8PerContextData {
public:
    static PassOwnPtr<V8PerContextData> create(v8::Handle<v8::Context> context)
    {
        return adoptPtr(new V8PerContextData(context));
    }

    ~V8PerContextData()
    {
        dispose();
    }

    bool init();

    static V8PerContextData* from(v8::Handle<v8::Context> context)
    {
        return static_cast<V8PerContextData*>(context->GetAlignedPointerFromEmbedderData(v8ContextPerContextDataIndex));
    }

    // To create JS Wrapper objects, we create a cache of a 'boiler plate'
    // object, and then simply Clone that object each time we need a new one.
    // This is faster than going through the full object creation process.
    v8::Local<v8::Object> createWrapperFromCache(WrapperTypeInfo* type)
    {
        UnsafePersistent<v8::Object> boilerplate = m_wrapperBoilerplates.get(type);
        return !boilerplate.isEmpty() ? boilerplate.newLocal(v8::Isolate::GetCurrent())->Clone() : createWrapperFromCacheSlowCase(type);
    }

    v8::Local<v8::Function> constructorForType(WrapperTypeInfo* type)
    {
        UnsafePersistent<v8::Function> function = m_constructorMap.get(type);
        if (!function.isEmpty())
            return function.newLocal(v8::Isolate::GetCurrent());
        return constructorForTypeSlowCase(type);
    }

    v8::Local<v8::Object> prototypeForType(WrapperTypeInfo*);

    V8NPObjectMap* v8NPObjectMap()
    {
        return &m_v8NPObjectMap;
    }

    V8DOMActivityLogger* activityLogger()
    {
        return m_activityLogger;
    }

    void setActivityLogger(V8DOMActivityLogger* logger)
    {
        m_activityLogger = logger;
    }

    void addCustomElementBinding(CustomElementDefinition*, PassOwnPtr<CustomElementBinding>);
    void clearCustomElementBinding(CustomElementDefinition*);
    CustomElementBinding* customElementBinding(CustomElementDefinition*);

private:
    explicit V8PerContextData(v8::Handle<v8::Context> context)
        : m_activityLogger(0)
        , m_isolate(v8::Isolate::GetCurrent())
        , m_context(m_isolate, context)
        , m_customElementBindings(adoptPtr(new CustomElementBindingMap()))
    {
    }

    void dispose();

    v8::Local<v8::Object> createWrapperFromCacheSlowCase(WrapperTypeInfo*);
    v8::Local<v8::Function> constructorForTypeSlowCase(WrapperTypeInfo*);

    // For each possible type of wrapper, we keep a boilerplate object.
    // The boilerplate is used to create additional wrappers of the same type.
    typedef WTF::HashMap<WrapperTypeInfo*, UnsafePersistent<v8::Object> > WrapperBoilerplateMap;
    WrapperBoilerplateMap m_wrapperBoilerplates;

    typedef WTF::HashMap<WrapperTypeInfo*, UnsafePersistent<v8::Function> > ConstructorMap;
    ConstructorMap m_constructorMap;

    V8NPObjectMap m_v8NPObjectMap;
    // We cache a pointer to the V8DOMActivityLogger associated with the world
    // corresponding to this context. The ownership of the pointer is retained
    // by the DOMActivityLoggerMap in DOMWrapperWorld.
    V8DOMActivityLogger* m_activityLogger;
    v8::Isolate* m_isolate;
    v8::Persistent<v8::Context> m_context;
    ScopedPersistent<v8::Value> m_errorPrototype;

    typedef WTF::HashMap<CustomElementDefinition*, OwnPtr<CustomElementBinding> > CustomElementBindingMap;
    OwnPtr<CustomElementBindingMap> m_customElementBindings;
};

class V8PerContextDebugData {
public:
    static bool setContextDebugData(v8::Handle<v8::Context>, const char* worldName, int debugId);
    static int contextDebugId(v8::Handle<v8::Context>);
};

} // namespace WebCore

#endif // V8PerContextData_h