/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2007 INRIA

 * All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#ifndef INTERFACE_H

#define INTERFACE_H

#include <string>

#include "ptr.h"

namespace ns3 {

class NsUnknownImpl;

class Iid

{

public:

  Iid (std::string name);

private:

  friend bool operator == (const Iid &a, const Iid &b);

  uint32_t m_iid;

};

/**

 * \brief COM-like IUnknown

 *

 * This class should be used as a base class for every object which

 * wishes to provide a COM-like QueryInterface API. Multiple 

 * inheritance where this base class is at the top of the dreaded 

 * "diamond" shape is not allowed.

 */

class NsUnknown

{

public:

  virtual ~NsUnknown ();

  void Ref (void) const;

  void Unref (void) const;

  /**

   * \param iid the NsUnknown id of the requested interface

   */

  template <typename T>

  Ptr<T> QueryInterface (Iid iid) const;

  /**

   * \param interface another interface

   * 

   * Aggregate together the two interfaces. After this call,

   * the two interface objects are tied together: each of them

   * will be able to perform QI on each other and their lifetimes

   * will be found by the same reference count.

   */

  void AddInterface (Ptr<NsUnknown> interface);

  void Dispose (void);

protected:

  /**

   * \param iid the Interface Id of the interface defined by a direct subclass

   * of this base class

   *

   * If you are a direct subclass of this class, you _must_ register

   * the name of your interface with this constructor.

   */

  NsUnknown (Iid iid);

  /**

   * \param iid the Interface id of the interface

   * \param a pointer to the interface object

   *

   * If you are not a direct subclass of the ns3::NsUnknown base class,

   * and if you want to register yourself as another accessible interface

   * (typically, your subclass has added API), you need to call

   * this method to associate an interface id to your interface.

   */

  void AddSelfInterface (Iid iid, Ptr<NsUnknown> interface);

protected:

  /**

   * Subclasses who want to handle the "dispose" event should

   * override this method. They are also responsible for

   * "chaining up" to their parent class' DoDispose method

   * once they have done their own "dispose".

   */

  virtual void DoDispose (void);

private:

  friend class NsUnknownImpl;

  NsUnknown ();

  Ptr<NsUnknown> DoQueryInterface (Iid iid) const;

  void RefInternal (void);

  void UnrefInternal (void);

  NsUnknownImpl *m_impl;

  uint32_t m_ref;

};

}//namespace ns3

namespace ns3 {

template <typename T>

Ptr<T>

NsUnknown::QueryInterface (Iid iid) const

{

  Ptr<NsUnknown> found = DoQueryInterface (iid);

  if (found != 0)

    {

      return Ptr<T> (dynamic_cast<T *> (PeekPointer (found)));

    }

  return 0;

}

}//namespace ns3

#endif /* INTERFACE_H */