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

/*

 * Copyright (c) 2005,2006 INRIA

 *

 * 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 CALLBACK_H

#define CALLBACK_H

#include "ptr.h"

#include "fatal-error.h"

#include "empty.h"

#include "type-traits.h"

#include <typeinfo>

namespace ns3 {

/***

 * \internal

 * This code was originally written based on the techniques 

 * described in http://www.codeproject.com/cpp/TTLFunction.asp

 * It was subsequently rewritten to follow the architecture

 * outlined in "Modern C++ Design" by Andrei Alexandrescu in 

 * chapter 5, "Generalized Functors".

 *

 * This code uses:

 *   - default template parameters to saves users from having to

 *     specify empty parameters when the number of parameters

 *     is smaller than the maximum supported number

 *   - the pimpl idiom: the Callback class is passed around by 

 *     value and delegates the crux of the work to its pimpl

 *     pointer.

 *   - two pimpl implementations which derive from CallbackImpl

 *     FunctorCallbackImpl can be used with any functor-type

 *     while MemPtrCallbackImpl can be used with pointers to

 *     member functions.

 *   - a reference list implementation to implement the Callback's

 *     value semantics.

 *

 * This code most notably departs from the alexandrescu 

 * implementation in that it does not use type lists to specify

 * and pass around the types of the callback arguments.

 * Of course, it also does not use copy-destruction semantics

 * and relies on a reference list rather than autoPtr to hold

 * the pointer.

 */

template <typename T>

struct CallbackTraits;

template <typename T>

struct CallbackTraits<T *>

{

  static T & GetReference (T * const p)

  {

    return *p;

  }

};

class CallbackImplBase

{

public:

  CallbackImplBase ()

    : m_count (1) {}

  virtual ~CallbackImplBase () {}

  void Ref (void) const {

    m_count++;

  }

  void Unref (void) const {

    m_count--;

    if (m_count == 0) {

      delete this;

    }

  }

  virtual bool IsEqual (Ptr<const CallbackImplBase> other) const = 0;

private:

  mutable uint32_t m_count;

};

// declare the CallbackImpl class

template <typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>

class CallbackImpl;

// define CallbackImpl for 0 params

template <typename R>

class CallbackImpl<R,empty,empty,empty,empty,empty,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (void) = 0;

};

// define CallbackImpl for 1 params

template <typename R, typename T1>

class CallbackImpl<R,T1,empty,empty,empty,empty,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1) = 0;

};

// define CallbackImpl for 2 params

template <typename R, typename T1, typename T2>

class CallbackImpl<R,T1,T2,empty,empty,empty,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1, T2) = 0;

};

// define CallbackImpl for 3 params

template <typename R, typename T1, typename T2, typename T3>

class CallbackImpl<R,T1,T2,T3,empty,empty,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1, T2, T3) = 0;

};

// define CallbackImpl for 4 params

template <typename R, typename T1, typename T2, typename T3, typename T4>

class CallbackImpl<R,T1,T2,T3,T4,empty,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1, T2, T3, T4) = 0;

};

// define CallbackImpl for 5 params

template <typename R, typename T1, typename T2, typename T3, typename T4, typename T5>

class CallbackImpl<R,T1,T2,T3,T4,T5,empty> : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1, T2, T3, T4, T5) = 0;

};

// define CallbackImpl for 6 params

  template <typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>

class CallbackImpl : public CallbackImplBase {

public:

  virtual ~CallbackImpl () {}

  virtual R operator() (T1, T2, T3, T4, T5, T6) = 0;

};

// an impl for Functors:

template <typename T, typename R, typename T1, typename T2, typename T3, typename T4,typename T5, typename T6>

class FunctorCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6> {

public:

  FunctorCallbackImpl (T const &functor)

    : m_functor (functor) {}

  virtual ~FunctorCallbackImpl () {}

  R operator() (void) {

      return m_functor ();

  }

  R operator() (T1 a1) {

      return m_functor (a1);

  }

  R operator() (T1 a1,T2 a2) {

      return m_functor (a1,a2);

  }

  R operator() (T1 a1,T2 a2,T3 a3) {

      return m_functor (a1,a2,a3);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4) {

      return m_functor (a1,a2,a3,a4);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4,T5 a5) {

      return m_functor (a1,a2,a3,a4,a5);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4,T5 a5,T6 a6) {

    return m_functor (a1,a2,a3,a4,a5,a6);

  }

  virtual bool IsEqual (Ptr<const CallbackImplBase> other) const {

    FunctorCallbackImpl<T,R,T1,T2,T3,T4,T5,T6> const *otherDerived = 

      dynamic_cast<FunctorCallbackImpl<T,R,T1,T2,T3,T4,T5,T6> const *> (PeekPointer(other));

    if (otherDerived == 0)

      {

        return false;

      }

    else if (otherDerived->m_functor != m_functor)

      {

        return false;

      }

    return true;

  }

private:

  T m_functor;

};

// an impl for pointer to member functions

template <typename OBJ_PTR, typename MEM_PTR, typename R, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>

class MemPtrCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,T6> {

public:

  MemPtrCallbackImpl (OBJ_PTR const&objPtr, MEM_PTR mem_ptr)

    : m_objPtr (objPtr), m_memPtr (mem_ptr) {}

  virtual ~MemPtrCallbackImpl () {}

  R operator() (void) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) ();

  }

  R operator() (T1 a1) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1);

  }

  R operator() (T1 a1,T2 a2) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1, a2);

  }

  R operator() (T1 a1,T2 a2,T3 a3) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1, a2, a3);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1, a2, a3, a4);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4,T5 a5) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1, a2, a3, a4, a5);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4,T5 a5,T6 a6) {

    return ((CallbackTraits<OBJ_PTR>::GetReference (m_objPtr)).*m_memPtr) (a1, a2, a3, a4, a5, a6);

  }

  virtual bool IsEqual (Ptr<const CallbackImplBase> other) const {

    MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6> const *otherDerived = 

      dynamic_cast<MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6> const *> (PeekPointer (other));

    if (otherDerived == 0)

      {

        return false;

      }

    else if (otherDerived->m_objPtr != m_objPtr ||

             otherDerived->m_memPtr != m_memPtr)

      {

        return false;

      }

    return true;

  }

private:

  OBJ_PTR const m_objPtr;

  MEM_PTR m_memPtr;

};

// an impl for Bound Functors:

template <typename T, typename R, typename TX, typename T1, typename T2, typename T3, typename T4,typename T5>

class BoundFunctorCallbackImpl : public CallbackImpl<R,T1,T2,T3,T4,T5,empty> {

public:

  template <typename FUNCTOR, typename ARG>

  BoundFunctorCallbackImpl (FUNCTOR functor, ARG a)

      : m_functor (functor), m_a (a) {}

  virtual ~BoundFunctorCallbackImpl () {}

  R operator() (void) {

      return m_functor (m_a);

  }

  R operator() (T1 a1) {

      return m_functor (m_a,a1);

  }

  R operator() (T1 a1,T2 a2) {

      return m_functor (m_a,a1,a2);

  }

  R operator() (T1 a1,T2 a2,T3 a3) {

      return m_functor (m_a,a1,a2,a3);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4) {

      return m_functor (m_a,a1,a2,a3,a4);

  }

  R operator() (T1 a1,T2 a2,T3 a3,T4 a4,T5 a5) {

      return m_functor (m_a,a1,a2,a3,a4,a5);

  }

  virtual bool IsEqual (Ptr<const CallbackImplBase> other) const {

    BoundFunctorCallbackImpl<T,R,TX,T1,T2,T3,T4,T5> const *otherDerived = 

      dynamic_cast<BoundFunctorCallbackImpl<T,R,TX,T1,T2,T3,T4,T5> const *> (PeekPointer (other));

    if (otherDerived == 0)

      {

        return false;

      }

    else if (otherDerived->m_functor != m_functor ||

             otherDerived->m_a != m_a)

      {

        return false;

      }

    return true;

  }

private:

  T m_functor;

  typename TypeTraits<TX>::ReferencedType m_a;

};

class CallbackBase {

public:

  CallbackBase () : m_impl () {}

  Ptr<CallbackImplBase> GetImpl (void) const {return m_impl;}

protected:

  CallbackBase (Ptr<CallbackImplBase> impl) : m_impl (impl) {}

  Ptr<CallbackImplBase> m_impl;

};

/**

 * \brief Callback template class

 *

 * This class template implements the Functor Design Pattern.

 * It is used to declare the type of a Callback:

 *  - the first non-optional template argument represents

 *    the return type of the callback.

 *  - the second optional template argument represents

 *    the type of the first argument to the callback.

 *  - the third optional template argument represents

 *    the type of the second argument to the callback.

 *  - the fourth optional template argument represents

 *    the type of the third argument to the callback.

 *  - the fifth optional template argument represents

 *    the type of the fourth argument to the callback.

 *  - the sixth optional template argument represents

 *    the type of the fifth argument to the callback.

 *

 * Callback instances are built with the \ref MakeCallback

 * template functions. Callback instances have POD semantics:

 * the memory they allocate is managed automatically, without

 * user intervention which allows you to pass around Callback

 * instances by value.

 *

 * Sample code which shows how to use this class template 

 * as well as the function templates \ref MakeCallback :

 * \include samples/main-callback.cc

 */

template<typename R, 

   typename T1 = empty, typename T2 = empty, 

   typename T3 = empty, typename T4 = empty,

   typename T5 = empty, typename T6 = empty>

class Callback : public CallbackBase {

public:

  Callback () {}

  // There are two dummy args below to ensure that this constructor is

  // always properly disambiguited by the c++ compiler

  template <typename FUNCTOR>

  Callback (FUNCTOR const &functor, bool, bool) 

    : CallbackBase (Create<FunctorCallbackImpl<FUNCTOR,R,T1,T2,T3,T4,T5,T6> > (functor))

  {}

  template <typename OBJ_PTR, typename MEM_PTR>

  Callback (OBJ_PTR const &objPtr, MEM_PTR mem_ptr)

    : CallbackBase (Create<MemPtrCallbackImpl<OBJ_PTR,MEM_PTR,R,T1,T2,T3,T4,T5,T6> > (objPtr, mem_ptr))

  {}

  Callback (Ptr<CallbackImpl<R,T1,T2,T3,T4,T5,T6> > const &impl)

    : CallbackBase (impl)

  {}

  template <typename T>

  Callback<R,T2,T3,T4,T5,T6> Bind (T a) {

    Ptr<CallbackImpl<R,T2,T3,T4,T5,T6,empty> > impl =

      Ptr<CallbackImpl<R,T2,T3,T4,T5,T6,empty> > (

                                            new BoundFunctorCallbackImpl<

                                            Callback<R,T1,T2,T3,T4,T5,T6>,

                                            R,T1,T2,T3,T4,T5,T6> (*this, a), false);

    return Callback<R,T2,T3,T4,T5,T6> (impl);

  }

  bool IsNull (void) const {

    return (DoPeekImpl () == 0)?true:false;

  }

  void Nullify (void) {

    m_impl = 0;

  }

  R operator() (void) const {

    return (*(DoPeekImpl ())) ();

  }

  R operator() (T1 a1) const {

    return (*(DoPeekImpl ())) (a1);

  }

  R operator() (T1 a1, T2 a2) const {

    return (*(DoPeekImpl ())) (a1,a2);

  }

  R operator() (T1 a1, T2 a2, T3 a3) const {

    return (*(DoPeekImpl ())) (a1,a2,a3);

  }

  R operator() (T1 a1, T2 a2, T3 a3, T4 a4) const {

    return (*(DoPeekImpl ())) (a1,a2,a3,a4);

  }

  R operator() (T1 a1, T2 a2, T3 a3, T4 a4,T5 a5) const {

    return (*(DoPeekImpl ())) (a1,a2,a3,a4,a5);

  }

  R operator() (T1 a1, T2 a2, T3 a3, T4 a4,T5 a5,T6 a6) const {

    return (*(DoPeekImpl ())) (a1,a2,a3,a4,a5,a6);

  }

  bool IsEqual (const CallbackBase &other) const {

    return m_impl->IsEqual (other.GetImpl ());

  }

  bool CheckType (const CallbackBase & other) const {

    return DoCheckType (other.GetImpl ());

  }

  void Assign (const CallbackBase &other) {

    DoAssign (other.GetImpl ());

  }

private:

  CallbackImpl<R,T1,T2,T3,T4,T5,T6> *DoPeekImpl (void) const {

    return static_cast<CallbackImpl<R,T1,T2,T3,T4,T5,T6> *> (PeekPointer (m_impl));

  }

  bool DoCheckType (Ptr<const CallbackImplBase> other) const {

    if (dynamic_cast<const CallbackImpl<R,T1,T2,T3,T4,T5,T6> *> (PeekPointer (other)) != 0)

      {

        return true;

      }

    else

      {

        return false;

      }

  }

  void DoAssign (Ptr<const CallbackImplBase> other) {

    if (!DoCheckType (other))

      {

        NS_FATAL_ERROR ("Incompatible types. (feed to \"c++filt -t\")"

                        " got=" << typeid (*other).name () << 

                        ", expected=" << typeid (CallbackImpl<R,T1,T2,T3,T4,T5,T6> *).name ());

      }

    m_impl = const_cast<CallbackImplBase *> (PeekPointer (other));

  }

};

template <typename R, typename T1, typename T2,

          typename T3, typename T4,

          typename T5, typename T6>

bool operator != (Callback<R,T1,T2,T3,T4,T5,T6> a, Callback<R,T1,T2,T3,T4,T5,T6> b)

{

  return !a.IsEqual (b);

}

/**

 * \ingroup core

 * \defgroup MakeCallback MakeCallback

 *

 */

/**

 * \ingroup MakeCallback

 * \param memPtr class method member pointer

 * \param objPtr class instance

 * \return a wrapper Callback

 * Build Callbacks for class method members which takes no arguments

 * and potentially return a value.

 */

template <typename T, typename OBJ, typename R>

Callback<R> MakeCallback (R (T::*memPtr) (void), OBJ objPtr) {

  return Callback<R> (objPtr, memPtr);

}

template <typename T, typename OBJ, typename R>

Callback<R> MakeCallback (R (T::*mem_ptr) () const, OBJ objPtr) {

  return Callback<R> (objPtr, mem_ptr);

}

/**

 * \ingroup MakeCallback

 * \param mem_ptr class method member pointer

 * \param objPtr class instance

 * \return a wrapper Callback

 * Build Callbacks for class method members which takes one argument

 * and potentially return a value.

 */

template <typename T, typename OBJ, typename R, typename T1>

Callback<R,T1> MakeCallback (R (T::*mem_ptr) (T1), OBJ objPtr) {

  return Callback<R,T1> (objPtr, mem_ptr);

}

template <typename T, typename OBJ, typename R, typename T1>

Callback<R,T1> MakeCallback (R (T::*mem_ptr) (T1) const, OBJ objPtr) {

  return Callback<R,T1> (objPtr, mem_ptr);

}

/**

 * \ingroup MakeCallback

 * \param mem_ptr class method member pointer

 * \param objPtr class instance

 * \return a wrapper Callback

 * Build Callbacks for class method members which takes two arguments

 * and potentially return a value.

 */

template <typename T, typename OBJ, typename R, typename T1, typename T2>

Callback<R,T1,T2> MakeCallback (R (T::*mem_ptr) (T1,T2), OBJ objPtr) {

  return Callback<R,T1,T2> (objPtr, mem_ptr);

}

template <typename T, typename OBJ, typename R, typename T1, typename T2>

Callback<R,T1,T2> MakeCallback (R (T::*mem_ptr) (T1,T2) const, OBJ objPtr) {

  return Callback<R,T1,T2> (objPtr, mem_ptr);

}

/**

 * \ingroup MakeCallback

 * \param mem_ptr class method member pointer

 * \param objPtr class instance

 * \return a wrapper Callback

 * Build Callbacks for class method members which takes three arguments

 * and potentially return a value.

 */