/*
 * Copyright 2001-2009, Ingo Weinhold, ingo_weinhold@gmx.de.
 * Distributed under the terms of the MIT License.
 */
#ifndef USERLAND_FS_OBJECT_TRACKER_H
#define USERLAND_FS_OBJECT_TRACKER_H

#include <util/DoublyLinkedList.h>

#include "Locker.h"

namespace UserlandFSUtil {

class ObjectTracker;
class GetObjectTrackableLink;

// ObjectTrackable
class ObjectTrackable {
public:
                                                                ObjectTrackable();
        virtual                                         ~ObjectTrackable();

private:
        friend class ObjectTracker;
        friend class GetObjectTrackableLink;

                        DoublyLinkedListLink<ObjectTrackable> fLink;
};

// GetObjectTrackableLink
struct GetObjectTrackableLink {
        inline DoublyLinkedListLink<ObjectTrackable> *operator()(
                ObjectTrackable* trackable) const
        {
                return &trackable->fLink;
        }

        inline const DoublyLinkedListLink<ObjectTrackable> *operator()(
                const ObjectTrackable* trackable) const
        {
                return &trackable->fLink;
        }
};

// ObjectTracker
class ObjectTracker {
private:
                                                                ObjectTracker();
                                                                ~ObjectTracker();

public:

        static  ObjectTracker*          InitDefault();
        static  void                            ExitDefault();
        static  ObjectTracker*          GetDefault();

private:
                        friend class ObjectTrackable;

                        void                            AddTrackable(ObjectTrackable* trackable);
                        void                            RemoveTrackable(ObjectTrackable* trackable);

private:
                        Locker                          fLock;
                        DoublyLinkedList<ObjectTrackable, GetObjectTrackableLink>
                                fTrackables;

        static  ObjectTracker*          sTracker;
};

}       // namespace UserlandFSUtil

using UserlandFSUtil::ObjectTrackable;
using UserlandFSUtil::ObjectTracker;

#ifdef DEBUG_OBJECT_TRACKING
#       define ONLY_OBJECT_TRACKABLE_BASE_CLASS         : private ObjectTrackable
#       define FIRST_OBJECT_TRACKABLE_BASE_CLASS        private ObjectTrackable,
#else
#       define ONLY_OBJECT_TRACKABLE_BASE_CLASS
#       define FIRST_OBJECT_TRACKABLE_BASE_CLASS
#endif

#endif  // USERLAND_FS_OBJECT_TRACKER_H