scoped_ptr.hpp

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//////////////////////////////////////////////////////////////////////////////
//
// This file is the adaptation for Interprocess of boost/scoped_ptr.hpp
//
// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
// (C) Copyright Peter Dimov 2001, 2002
// (C) Copyright Ion Gaztanaga 2006. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_SCOPED_PTR_HPP_INCLUDED
#define BOOST_INTERPROCESS_SCOPED_PTR_HPP_INCLUDED

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/detail/pointer_type.hpp>
#include <boost/assert.hpp>

//!\file
//!Describes the smart pointer scoped_ptr

namespace boost {
namespace interprocess {

//!scoped_ptr stores a pointer to a dynamically allocated object. 
//!The object pointed to is guaranteed to be deleted, either on destruction
//!of the scoped_ptr, or via an explicit reset. The user can avoid this
//!deletion using release().
//!scoped_ptr is parameterized on T (the type of the object pointed to) and 
//!Deleter (the functor to be executed to delete the internal pointer).
//!The internal pointer will be of the same pointer type as typename 
//!Deleter::pointer type (that is, if typename Deleter::pointer is 
//!offset_ptr<void>, the internal pointer will be offset_ptr<T>).
template<class T, class Deleter>
class scoped_ptr
   : private Deleter
{
   /// @cond
   scoped_ptr(scoped_ptr const &);
   scoped_ptr & operator=(scoped_ptr const &);

   typedef scoped_ptr<T, Deleter> this_type;
   typedef typename detail::add_reference<T>::type reference;
   /// @endcond

   public:

   typedef T element_type;
   typedef Deleter deleter_type;
   typedef typename detail::pointer_type<T, Deleter>::type pointer;

   //!Provides the type of the internal stored pointer
//   typedef typename detail::pointer_to_other
//            <typename Deleter::pointer, T>::type pointer;

   //!Constructs a scoped_ptr, storing a copy of p(which can be 0) and d.
   //!Does not throw.
   explicit scoped_ptr(const pointer &p = 0, const Deleter &d = Deleter())
      : Deleter(d), m_ptr(p) // throws if pointer/Deleter copy ctor throws
   {}

   //!If the stored pointer is not 0, destroys the object pointed to by the stored pointer. 
   //!calling the operator() of the stored deleter. Never throws
   ~scoped_ptr()
   { 
      if(m_ptr){
         Deleter &del = static_cast<Deleter&>(*this);
         del(m_ptr);
      }
   }

   //!Deletes the object pointed to by the stored pointer and then
   //!stores a copy of p. Never throws
   void reset(const pointer &p = 0) // never throws
   {  BOOST_ASSERT(p == 0 || p != m_ptr); this_type(p).swap(*this);  }

   //!Deletes the object pointed to by the stored pointer and then
   //!stores a copy of p and a copy of d.
   void reset(const pointer &p, const Deleter &d) // never throws
   {  BOOST_ASSERT(p == 0 || p != m_ptr); this_type(p).swap(*this);  }

   //!Assigns internal pointer as 0 and returns previous pointer. This will
   //!avoid deletion on destructor
   pointer release()
   {  pointer tmp(m_ptr);  m_ptr = 0;  return tmp; }

   //!Returns a reference to the object pointed to by the stored pointer.
   //!Never throws.
   reference operator*() const
   {  BOOST_ASSERT(m_ptr != 0);  return *m_ptr; }

   //!Returns the internal stored pointer.
   //!Never throws.
   pointer &operator->()
   {  BOOST_ASSERT(m_ptr != 0);  return m_ptr;  }

   //!Returns the internal stored pointer.
   //!Never throws.
   const pointer &operator->() const
   {  BOOST_ASSERT(m_ptr != 0);  return m_ptr;  }

   //!Returns the stored pointer.
   //!Never throws.
   pointer & get()
   {  return m_ptr;  }

   //!Returns the stored pointer.
   //!Never throws.
   const pointer & get() const
   {  return m_ptr;  }

   typedef pointer this_type::*unspecified_bool_type;

   //!Conversion to bool
   //!Never throws
   operator unspecified_bool_type() const
   {  return m_ptr == 0? 0: &this_type::m_ptr;  }

   //!Returns true if the stored pointer is 0.
   //!Never throws.
   bool operator! () const // never throws
   {  return m_ptr == 0;   }

   //!Exchanges the internal pointer and deleter with other scoped_ptr
   //!Never throws.
   void swap(scoped_ptr & b) // never throws
   {  detail::do_swap<Deleter>(*this, b); detail::do_swap(m_ptr, b.m_ptr); }

   /// @cond
   private:
   pointer m_ptr;
   /// @endcond
};

//!Exchanges the internal pointer and deleter with other scoped_ptr
//!Never throws.
template<class T, class D> inline
void swap(scoped_ptr<T, D> & a, scoped_ptr<T, D> & b)
{  a.swap(b); }

//!Returns a copy of the stored pointer
//!Never throws
template<class T, class D> inline
typename scoped_ptr<T, D>::pointer get_pointer(scoped_ptr<T, D> const & p)
{  return p.get();   }

} // namespace interprocess

/// @cond

#if defined(_MSC_VER) && (_MSC_VER < 1400)
template<class T, class D> inline
T *get_pointer(boost::interprocess::scoped_ptr<T, D> const & p)
{  return p.get();   }
#endif

/// @endcond

} // namespace boost

#include <boost/interprocess/detail/config_end.hpp>

#endif // #ifndef BOOST_INTERPROCESS_SCOPED_PTR_HPP_INCLUDED