1 /////////////////////////////////////////////////////////////////////////////// 2 /// \file is_noncopyable.hpp 3 /// Utility for detecting when types are non-copyable 4 // 5 // Copyright 2008 Eric Niebler. Distributed under the Boost 6 // Software License, Version 1.0. (See accompanying file 7 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 8 9 #ifndef BOOST_PROTO_DETAIL_IS_NONCOPYABLE_HPP_EAN_19_07_2012 10 #define BOOST_PROTO_DETAIL_IS_NONCOPYABLE_HPP_EAN_19_07_2012 11 12 #include <boost/noncopyable.hpp> 13 #include <boost/mpl/or.hpp> 14 #include <boost/mpl/bool.hpp> 15 #include <boost/type_traits/is_base_of.hpp> 16 #include <boost/type_traits/is_abstract.hpp> 17 #include <boost/type_traits/is_function.hpp> 18 #include <boost/proto/proto_fwd.hpp> 19 20 namespace boost { namespace proto { namespace detail 21 { 22 // All classes derived from std::ios_base have these public nested types, 23 // and are non-copyable. This is an imperfect test, but it's the best we 24 // we can do. 25 template<typename T> 26 yes_type check_is_iostream( 27 typename T::failure * 28 , typename T::Init * 29 , typename T::fmtflags * 30 , typename T::iostate * 31 , typename T::openmode * 32 , typename T::seekdir * 33 ); 34 35 template<typename T> 36 no_type check_is_iostream(...); 37 38 template<typename T> 39 struct is_iostream 40 { 41 static bool const value = sizeof(yes_type) == sizeof(check_is_iostream<T>(0,0,0,0,0,0)); 42 typedef mpl::bool_<value> type; 43 }; 44 45 /// INTERNAL ONLY 46 // This should be a customization point. And it serves the same purpose 47 // as the is_noncopyable trait in Boost.Foreach. 48 template<typename T> 49 struct is_noncopyable 50 : mpl::or_< 51 is_function<T> 52 , is_abstract<T> 53 , is_iostream<T> 54 , is_base_of<noncopyable, T> 55 > 56 {}; 57 58 template<typename T, std::size_t N> 59 struct is_noncopyable<T[N]> 60 : mpl::true_ 61 {}; 62 63 }}} 64 65 #endif 66