3rdparty/boost/boost/signals2/trackable.hpp

   1 // Boost.Signals2 library
   2
   3 // Copyright Frank Mori Hess 2007,2009.
   4 // Copyright Timmo Stange 2007.
   5 // Copyright Douglas Gregor 2001-2004. Use, modification and
   6 // distribution is subject to the Boost Software License, Version
   7 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   8 // http://www.boost.org/LICENSE_1_0.txt)
   9
  10 // Compatibility class to ease porting from the original
  11 // Boost.Signals library.  However,
  12 // boost::signals2::trackable is NOT thread-safe.
  13
  14 // For more information, see http://www.boost.org
  15
  16 #ifndef BOOST_SIGNALS2_TRACKABLE_HPP
  17 #define BOOST_SIGNALS2_TRACKABLE_HPP
  18
  19 #include <boost/assert.hpp>
  20 #include <boost/shared_ptr.hpp>
  21 #include <boost/weak_ptr.hpp>
  22
  23 namespace boost {
  24   namespace signals2 {
  25     namespace detail
  26     {
  27         class tracked_objects_visitor;
  28
  29         // trackable_pointee is used to identify the tracked shared_ptr
  30         // originating from the signals2::trackable class.  These tracked
  31         // shared_ptr are special in that we shouldn't bother to
  32         // increment their use count during signal invocation, since
  33         // they don't actually control the lifetime of the
  34         // signals2::trackable object they are associated with.
  35         class trackable_pointee
  36         {};
  37     }
  38     class trackable {
  39     protected:
  40       trackable(): _tracked_ptr(static_cast<detail::trackable_pointee*>(0)) {}
  41       trackable(const trackable &): _tracked_ptr(static_cast<detail::trackable_pointee*>(0)) {}
  42       trackable& operator=(const trackable &)
  43       {
  44           return *this;
  45       }
  46       ~trackable() {}
  47     private:
  48       friend class detail::tracked_objects_visitor;
  49       weak_ptr<detail::trackable_pointee> get_weak_ptr() const
  50       {
  51           return _tracked_ptr;
  52       }
  53
  54       shared_ptr<detail::trackable_pointee> _tracked_ptr;
  55     };
  56   } // end namespace signals2
  57 } // end namespace boost
  58
  59 #endif // BOOST_SIGNALS2_TRACKABLE_HPP