boost/interprocess/smart_ptr/enable_shared_from_this.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // This file is the adaptation for Interprocess of boost/enable_shared_from_this.hpp
   4 //
   5 // (C) Copyright Peter Dimov 2002
   6 // (C) Copyright Ion Gaztanaga 2006. Distributed under the Boost
   7 // Software License, Version 1.0. (See accompanying file
   8 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10 // See http://www.boost.org/libs/interprocess for documentation.
  11 //
  12 //////////////////////////////////////////////////////////////////////////////
  13
  14 #ifndef BOOST_INTERPROCESS_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
  15 #define BOOST_INTERPROCESS_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
  16
  17 #include <boost/interprocess/detail/workaround.hpp>
  18 #include <boost/interprocess/detail/config_begin.hpp>
  19
  20 #include <boost/assert.hpp>
  21 #include <boost/interprocess/smart_ptr/weak_ptr.hpp>
  22 #include <boost/interprocess/smart_ptr/shared_ptr.hpp>
  23
  24 //!\file
  25 //!Describes an utility to form a shared pointer from this
  26
  27 namespace boost{
  28 namespace interprocess{
  29
  30 //!This class is used as a base class that allows a shared_ptr to the current
  31 //!object to be obtained from within a member function.
  32 //!enable_shared_from_this defines two member functions called shared_from_this
  33 //!that return a shared_ptr<T> and shared_ptr<T const>, depending on constness, to this.
  34 template<class T, class A, class D>
  35 class enable_shared_from_this
  36 {
  37    /// @cond
  38    protected:
  39    enable_shared_from_this()
  40    {}
  41
  42    enable_shared_from_this(enable_shared_from_this const &)
  43    {}
  44
  45    enable_shared_from_this & operator=(enable_shared_from_this const &)
  46    {  return *this;  }
  47
  48    ~enable_shared_from_this()
  49    {}
  50    /// @endcond
  51
  52    public:
  53    shared_ptr<T, A, D> shared_from_this()
  54    {
  55       shared_ptr<T, A, D> p(_internal_weak_this);
  56       BOOST_ASSERT(detail::get_pointer(p.get()) == this);
  57       return p;
  58    }
  59
  60    shared_ptr<T const, A, D> shared_from_this() const
  61    {
  62       shared_ptr<T const, A, D> p(_internal_weak_this);
  63       BOOST_ASSERT(detail::get_pointer(p.get()) == this);
  64       return p;
  65    }
  66
  67    /// @cond
  68    typedef T element_type;
  69    mutable weak_ptr<element_type, A, D> _internal_weak_this;
  70    /// @endcond
  71 };
  72
  73 } // namespace interprocess
  74 } // namespace boost
  75
  76 #include <boost/interprocess/detail/config_end.hpp>
  77
  78 #endif  // #ifndef BOOST_INTERPROCESS_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED
  79