G4memory.hh

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//
#ifndef G4SHARED_PTR_HH_
#define G4SHARED_PTR_HH_

//#if __cplusplus >= 201103L
#include <memory>

#define G4shared_ptr std::shared_ptr
#define G4weak_ptr std::weak_ptr
#define G4static_pointer_cast std::static_pointer_cast
#define G4const_pointer_cast std::const_pointer_cast
#define G4dynamic_pointer_cast std::dynamic_pointer_cast
#define G4enable_shared_from_this std::enable_shared_from_this
#define G4enable_shared_from_this2 std::enable_shared_from_this
/*
#else
#include "CLHEP/Utility/memory.h"

#define G4shared_ptr G4::shared_ptr
#define G4weak_ptr G4::weak_ptr
#define G4static_pointer_cast G4::static_pointer_cast
#define G4const_pointer_cast G4::const_pointer_cast
#define G4dynamic_pointer_cast G4::dynamic_pointer_cast
#define G4enable_shared_from_this G4::enable_shared_from_this
#define G4enable_shared_from_this2 G4::enable_shared_from_this2

namespace G4
{
using CLHEP::shared_ptr;
using CLHEP::weak_ptr;
using CLHEP::static_pointer_cast;
using CLHEP::const_pointer_cast;
using CLHEP::dynamic_pointer_cast;
}

namespace CLHEP
{

template< typename T >
class enable_shared_from_this
{
protected:
  enable_shared_from_this()
{ }

  ~enable_shared_from_this()
  { }

  enable_shared_from_this( enable_shared_from_this const & )
  { }

  enable_shared_from_this &
  operator = ( enable_shared_from_this const & )
  {
    return *this;
  }

public:
  shared_ptr<T>
  shared_from_this()
  {
    shared_ptr<T>  p( weak_this_ );
    // assert( p.get() == this );
    return p;
  }

  shared_ptr<T const>
  shared_from_this() const
  {
    shared_ptr<T const>  p( weak_this_ );
    // assert( p.get() == this );
    return p;
  }

public: // actually private, but avoids compiler template friendship issues

  // Note: invoked automatically by shared_ptr; do not call
  template< typename X, typename Y >
  void
  _internal_accept_owner( shared_ptr<X> const * ppx, Y * py ) const
  {
    if( weak_this_.expired() )
      weak_this_ = shared_ptr<T>( *ppx, py );
  }

private:
  mutable weak_ptr<T>  weak_this_;
};  // enable_shared_from_this<>


//  enable_shared_from_this2.hpp

namespace detail
{

class esft2_deleter_wrapper
{
private:
  shared_ptr<void>  deleter_;

public:
  esft2_deleter_wrapper(){ }

  template< typename T >
  void
  set_deleter( shared_ptr<T> const & deleter )
  {
    deleter_ = deleter;
  }

  template< typename T >
  void
  operator () ( T* )
  {
    assert( deleter_.use_count() <= 1 );
    deleter_.reset();
  }
};

} // namespace detail

template< typename T >
class enable_shared_from_this2
{
protected:

  enable_shared_from_this2(){ }

  enable_shared_from_this2( enable_shared_from_this2 const & )
  { }

  enable_shared_from_this2 & operator = ( enable_shared_from_this2 const & )
  {
    return *this;
  }

  ~enable_shared_from_this2()
  {
    assert( shared_this_.use_count() <= 1 ); // ensure no dangling shared_ptrs
  }

private:
  mutable  weak_ptr<T>    weak_this_;
  mutable  shared_ptr<T>  shared_this_;

public:

  shared_ptr<T>
  shared_from_this()
  {
    init_weak_once();
    return shared_ptr<T>( weak_this_ );
  }

  shared_ptr<T const>
  shared_from_this() const
  {
    init_weak_once();
    return shared_ptr<T>( weak_this_ );
  }

private:

  void init_weak_once() const
  {
    if( weak_this_._empty() )
    {
      shared_this_.reset( static_cast< T* >( 0 )
          , detail::esft2_deleter_wrapper()
      );
      weak_this_ = shared_this_;
    }
  }

public:  // actually private, but avoids compiler template friendship issues

// Note: invoked automatically by shared_ptr; do not call
  template< typename X, typename Y >
  void
  _internal_accept_owner( shared_ptr<X> * ppx, Y * py ) const
  {
    assert( ppx != 0 );

    if( weak_this_.use_count() == 0 )
      weak_this_ = shared_ptr<T>( *ppx, py );
    else if( shared_this_.use_count() != 0 )
    {
      assert( ppx->unique() ); // no weak_ptrs should exist either, but there's no way to check that

      detail::esft2_deleter_wrapper *  pd
      = //boost::
          get_deleter<detail::esft2_deleter_wrapper>( shared_this_ );
      assert( pd != 0 );

      pd->set_deleter( *ppx );

      ppx->reset( shared_this_, ppx->get() );
      shared_this_.reset();
    }
  }
};  // enable_shared_from_this2<>
}

namespace G4
{
  using CLHEP::enable_shared_from_this;
  using CLHEP::enable_shared_from_this2;
}
#endif
*/

#endif /* G4SHARED_PTR_HH_ */