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

/*

 * Copyright (c) 2007 INRIA, Gustavo Carneiro

 *

 * 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

 *

 * Authors: Gustavo Carneiro <gjcarneiro@gmail.com>,

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

 */

#ifndef OBJECT_H

#define OBJECT_H

#include <stdint.h>

#include <string>

#include "ptr.h"

namespace ns3 {

class TraceResolver;

class CallbackBase;

/**

 * \brief a unique identifier for an interface.

 *

 * Instances of this class can be created only through

 * calls to ns3::MakeInterfaceId.

 *

 * Note: This class is quite similar to COM's UUIDs.

 */

class InterfaceId

{

public:

  /**

   * \param name the name of the requested interface

   * \returns the unique id associated with the requested

   *          name. 

   *

   * This method cannot fail: it will crash if the input 

   * name is not a valid interface name.

   */

  static InterfaceId LookupByName (std::string name);

  /**

   * \param iid a unique id 

   * \returns the parent of the requested id, as registered

   *          by ns3::MakeInterfaceId.

   *

   * This method cannot fail: it will crash if the input

   * id is not a valid interface id.

   */

  static InterfaceId LookupParent (InterfaceId iid);

  ~InterfaceId ();

private:

  InterfaceId (uint16_t iid);

  friend InterfaceId MakeInterfaceId (std::string name, const InterfaceId &parent);

  friend InterfaceId MakeObjectInterfaceId (void);

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

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

  uint16_t m_iid;

};

/**

 * \param name of the new InterfaceId to create.

 * \param parent the "parent" of the InterfaceId to create.

 * \returns a new InterfaceId

 * \relates InterfaceId

 *

 * Every InterfaceId is a child of another InterfaceId. The

 * top-most InterfaceId is Object::iid and its parent is 

 * itself.

 */

InterfaceId

MakeInterfaceId (std::string name, const InterfaceId &parent);

/**

 * \brief a base class which provides memory management and object aggregation

 *

 * Note: This base class is quite similar in spirit to IUnknown in COM or

 * BonoboObject in Bonobo: it provides three main methods: Ref, Unref and

 * QueryInterface.

 */

class Object

{

public:

  static const InterfaceId iid;

  Object ();

  virtual ~Object ();

  /**

   * Increment the reference count. This method should not be called

   * by user code. Object instances are expected to be used in conjunction

   * of the Ptr template which would make calling Ref unecessary and 

   * dangerous.

   */

  inline void Ref (void) const;

  /**

   * Decrement the reference count. This method should not be called

   * by user code. Object instances are expected to be used in conjunction

   * of the Ptr template which would make calling Ref unecessary and 

   * dangerous.

   */

  inline void Unref (void) const;

  /**

   * \param iid the interface requested

   * \returns a pointer to the requested interface or zero if it could not be found.

   * 

   */

  template <typename T>

  Ptr<T> QueryInterface (InterfaceId iid) const;

  /**

   * Run the DoDispose methods of this object and all the

   * objects aggregated to it.

   * After calling this method, the object is expected to be

   * totally unusable except for the Ref and Unref methods.

   * It is an error to call Dispose twice on the same object 

   * instance

   */

  void Dispose (void);

  /**

   * \param other another object pointer

   *

   * This method aggregates the two objects together: after this

   * method returns, it becomes possible to call QueryInterface

   * on one to get the other, and vice-versa. 

   */

  void AddInterface (Ptr<Object> other);

  void TraceConnect (std::string path, const CallbackBase &cb);

  void TraceDisconnect (std::string path, const CallbackBase &cb);

protected:

  /**

   * \param iid an InterfaceId

   *

   * Every subclass which defines a new InterfaceId for itself

   * should register this InterfaceId by calling this method

   * from its constructor.

   */

  void SetInterfaceId (InterfaceId iid);

  /**

   * This method is called by Object::Dispose.

   * Subclasses are expected to override this method and chain

   * up to their parent's implementation once they are done.

   */

  virtual void DoDispose (void);

private:

  Ptr<Object> DoQueryInterface (InterfaceId iid) const;

  bool Check (void) const;

  void MaybeDelete (void) const;

  mutable uint32_t m_count;

  InterfaceId m_iid;

  bool m_disposed;

  Object *m_next;

};

} // namespace ns3

namespace ns3 {

void

Object::Ref (void) const

{

  m_count++;

}

void

Object::Unref (void) const

{

  NS_ASSERT (Check ());

  m_count--;

  if (m_count == 0)

    {

      MaybeDelete ();

    }

}

template <typename T>

Ptr<T> 

Object::QueryInterface (InterfaceId iid) const

{

  Ptr<Object> found = DoQueryInterface (iid);

  if (found != 0)

    {

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

    }

  return 0;

}

} // namespace ns3

#endif /* OBJECT_H */