/*

 * Copyright (C) 2009 Google Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 * copyright notice, this list of conditions and the following disclaimer

 * in the documentation and/or other materials provided with the

 * distribution.

 *     * Neither the name of Google Inc. nor the names of its

 * 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

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef V8DOMMap_h

#define V8DOMMap_h

#include <wtf/HashMap.h>

#include <wtf/OwnPtr.h>

#include <v8.h>

namespace WebCore {

    class Node;

#if ENABLE(SVG)

    class SVGElementInstance;

#endif

    template <class KeyType, class ValueType> class AbstractWeakReferenceMap {

    public:

        AbstractWeakReferenceMap(v8::WeakReferenceCallback callback) : m_weakReferenceCallback(callback) { }

        virtual ~AbstractWeakReferenceMap() { }

        class Visitor {

        public:

            virtual void visitDOMWrapper(KeyType* key, v8::Persistent<ValueType> object) = 0;

        protected:

            virtual ~Visitor() { }

        };

        virtual v8::Persistent<ValueType> get(KeyType* obj) = 0;

        virtual void set(KeyType* obj, v8::Persistent<ValueType> wrapper) = 0;

        virtual bool contains(KeyType* obj) = 0;

        virtual void visit(Visitor* visitor) = 0;

        virtual bool removeIfPresent(KeyType* key, v8::Persistent<v8::Data> value) = 0;

        virtual void clear() = 0;

        v8::WeakReferenceCallback weakReferenceCallback() { return m_weakReferenceCallback; }

    private:

        v8::WeakReferenceCallback m_weakReferenceCallback;

    };

    typedef AbstractWeakReferenceMap<Node, v8::Object> DOMNodeMapping;

    // A table of wrappers with weak pointers.

    // This table allows us to avoid track wrapped objects for debugging

    // and for ensuring that we don't double wrap the same object.

    template<class KeyType, class ValueType> class WeakReferenceMap : public AbstractWeakReferenceMap<KeyType, ValueType> {

    public:

        typedef AbstractWeakReferenceMap<KeyType, ValueType> Parent;

        WeakReferenceMap(v8::WeakReferenceCallback callback) : Parent(callback) { }

        virtual ~WeakReferenceMap() { }

        // Get the JS wrapper object of an object.

        virtual v8::Persistent<ValueType> get(KeyType* obj)

        {

            ValueType* wrapper = m_map.get(obj);

            return wrapper ? v8::Persistent<ValueType>(wrapper) : v8::Persistent<ValueType>();

        }

        virtual void set(KeyType* obj, v8::Persistent<ValueType> wrapper)

        {

            ASSERT(!m_map.contains(obj));

            wrapper.MakeWeak(obj, Parent::weakReferenceCallback());

            m_map.set(obj, *wrapper);

        }

        virtual void forget(KeyType* obj)

        {

            ASSERT(obj);

            ValueType* wrapper = m_map.take(obj);

            if (!wrapper)

                return;

            v8::Persistent<ValueType> handle(wrapper);

            handle.Dispose();

            handle.Clear();

        }

        bool removeIfPresent(KeyType* key, v8::Persistent<v8::Data> value)

        {

            typename HashMap<KeyType*, ValueType*>::iterator it = m_map.find(key);

            if (it == m_map.end() || it->second != *value)

                return false;

            m_map.remove(it);

            value.Dispose();

            return true;

        }

        void clear()

        {

            m_map.clear();

        }

        bool contains(KeyType* obj) { return m_map.contains(obj); }

        virtual void visit(typename Parent::Visitor* visitor)

        {

            typename HashMap<KeyType*, ValueType*>::iterator it = m_map.begin();

            for (; it != m_map.end(); ++it)

                visitor->visitDOMWrapper(it->first, v8::Persistent<ValueType>(it->second));

        }

    protected:

        HashMap<KeyType*, ValueType*> m_map;

    };

    template <class KeyType> class DOMWrapperMap : public WeakReferenceMap<KeyType, v8::Object> {

    public:

        DOMWrapperMap(v8::WeakReferenceCallback callback) : WeakReferenceMap<KeyType, v8::Object>(callback) { }

    };

    // An opaque class that represents a set of DOM wrappers.

    class DOMDataStore;

    // A utility class to manage the lifetime of set of DOM wrappers.

    class DOMDataStoreHandle {

    public:

        DOMDataStoreHandle();

        ~DOMDataStoreHandle();

        DOMDataStore* getStore() const { return m_store.get(); }

    private:

        OwnPtr<DOMDataStore> m_store;

    };

    // A map from DOM node to its JS wrapper.

    DOMNodeMapping& getDOMNodeMap();

    void visitDOMNodesInCurrentThread(DOMWrapperMap<Node>::Visitor*);

    // A map from a DOM object (non-node) to its JS wrapper. This map does not contain the DOM objects which can have pending activity (active dom objects).

    DOMWrapperMap<void>& getDOMObjectMap();

    void visitDOMObjectsInCurrentThread(DOMWrapperMap<void>::Visitor*);

    // A map from a DOM object to its JS wrapper for DOM objects which can have pending activity.

    DOMWrapperMap<void>& getActiveDOMObjectMap();

    void visitActiveDOMObjectsInCurrentThread(DOMWrapperMap<void>::Visitor*);

    // This should be called to remove all DOM objects associated with the current thread when it is tearing down.

    void removeAllDOMObjectsInCurrentThread();

#if ENABLE(SVG)

    // A map for SVGElementInstances to its JS wrapper.

    DOMWrapperMap<SVGElementInstance>& getDOMSVGElementInstanceMap();

    void visitSVGElementInstancesInCurrentThread(DOMWrapperMap<SVGElementInstance>::Visitor*);

    // Map of SVG objects with contexts to V8 objects.

    DOMWrapperMap<void>& getDOMSVGObjectWithContextMap();

    void visitDOMSVGObjectsInCurrentThread(DOMWrapperMap<void>::Visitor*);

#endif

    void enableFasterDOMStoreAccess();

} // namespace WebCore

#endif // V8DOMMap_h