diff --git a/include/boost/move/traits.hpp b/include/boost/move/traits.hpp index ced1cdd..068f021 100644 --- a/include/boost/move/traits.hpp +++ b/include/boost/move/traits.hpp @@ -18,6 +18,7 @@ #include #include #include +#include #include #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES @@ -55,6 +56,15 @@ struct has_nothrow_move namespace move_detail { +template +struct has_nothrow_move_or_uncopyable + : public ::boost::move_detail::integral_constant + < bool + , has_nothrow_move::value || + !boost::is_copy_constructible::value + > +{}; + // Code from Jeffrey Lee Hellrung, many thanks #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES diff --git a/include/boost/move/utility.hpp b/include/boost/move/utility.hpp index d4219a1..8a8867c 100644 --- a/include/boost/move/utility.hpp +++ b/include/boost/move/utility.hpp @@ -18,6 +18,8 @@ #include #include #include +#include +#include #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED) @@ -81,6 +83,56 @@ return x; } + ////////////////////////////////////////////////////////////////////////////// + // + // move_if_noexcept() + // + ////////////////////////////////////////////////////////////////////////////// + + template + inline typename ::boost::move_detail::enable_if_c + < enable_move_utility_emulation::value && !has_move_emulation_enabled::value, typename add_const::type & >::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return x; + } + + template + inline typename ::boost::move_detail::enable_if_c + < enable_move_utility_emulation::value && has_move_emulation_enabled::value + && ::boost::move_detail::has_nothrow_move_or_uncopyable::value, rv&>::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return *static_cast* >(::boost::move_detail::addressof(x)); + } + + template + inline typename ::boost::move_detail::enable_if_c + < enable_move_utility_emulation::value && has_move_emulation_enabled::value + && ::boost::move_detail::has_nothrow_move_or_uncopyable::value, rv&>::type + move_if_noexcept(rv& x) BOOST_NOEXCEPT + { + return x; + } + + template + inline typename ::boost::move_detail::enable_if_c + < enable_move_utility_emulation::value && has_move_emulation_enabled::value + && !::boost::move_detail::has_nothrow_move_or_uncopyable::value, typename add_const::type & >::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return x; + } + + template + inline typename ::boost::move_detail::enable_if_c + < enable_move_utility_emulation::value && has_move_emulation_enabled::value + && !::boost::move_detail::has_nothrow_move_or_uncopyable::value, typename add_const::type & >::type + move_if_noexcept(rv& x) BOOST_NOEXCEPT + { + return x; + } + } //namespace boost #else //#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED) @@ -92,6 +144,7 @@ using ::std::move; using ::std::forward; + using ::std::move_if_noexcept; } //namespace boost @@ -183,6 +236,60 @@ #endif //BOOST_MOVE_DOXYGEN_INVOKED + ////////////////////////////////////////////////////////////////////////////// + // + // move_if_noexcept() + // + ////////////////////////////////////////////////////////////////////////////// + #if defined(BOOST_MOVE_DOXYGEN_INVOKED) + //! This function provides a way to convert a reference into a rvalue reference + //! in compilers with rvalue references. For other compilers converts T & into + //! ::boost::rv & so that move emulation is activated. Reference + //! would be converted to rvalue reference only if input type is nothrow move + //! constructible or if it has no copy constructor. In all other cases const + //! reference would be returned + template + rvalue_reference move_if_noexcept(input_reference) noexcept; + + #elif defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES) + + //Old move approach, lvalues could bind to rvalue references + template + inline typename ::boost::move_detail::enable_if_c + < ::boost::move_detail::has_nothrow_move_or_uncopyable::value, typename remove_reference::type&&>::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return ::boost::move(x); + } + + template + inline typename ::boost::move_detail::enable_if_c + < !::boost::move_detail::has_nothrow_move_or_uncopyable::value, + typename add_const::type>::type& + >::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return x; + } + + #else //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES + template + inline typename ::boost::move_detail::enable_if_c + < ::boost::move_detail::has_nothrow_move_or_uncopyable::value, T&&>::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return ::boost::move(x); + } + + template + inline typename ::boost::move_detail::enable_if_c + < !::boost::move_detail::has_nothrow_move_or_uncopyable::value, typename add_const::type & >::type + move_if_noexcept(T& x) BOOST_NOEXCEPT + { + return x; + } + #endif //BOOST_MOVE_DOXYGEN_INVOKED + } //namespace boost { #endif //#if defined(BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE) diff --git a/test/move_if_noexcept.cpp b/test/move_if_noexcept.cpp new file mode 100644 index 0000000..805af51 --- /dev/null +++ b/test/move_if_noexcept.cpp @@ -0,0 +1,228 @@ +////////////////////////////////////////////////////////////////////////////// +// +// (C) Copyright Antony Polukhin 2014. +// 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/move for documentation. +// +////////////////////////////////////////////////////////////////////////////// +#include +#include +#include "../example/movable.hpp" +#include "../example/copymovable.hpp" +#include + +////////////////////////////////////////////////////////////////////////////// +//A copy_movable_noexcept class +class copy_movable_noexcept +{ + BOOST_COPYABLE_AND_MOVABLE(copy_movable_noexcept) + int value_; + + public: + copy_movable_noexcept() : value_(1){} + + //Move constructor and assignment + copy_movable_noexcept(BOOST_RV_REF(copy_movable_noexcept) m) + { value_ = m.value_; m.value_ = 0; } + + copy_movable_noexcept(const copy_movable_noexcept &m) + { value_ = m.value_; } + + copy_movable_noexcept & operator=(BOOST_RV_REF(copy_movable_noexcept) m) + { value_ = m.value_; m.value_ = 0; return *this; } + + copy_movable_noexcept & operator=(BOOST_COPY_ASSIGN_REF(copy_movable_noexcept) m) + { value_ = m.value_; return *this; } + + bool moved() const //Observer + { return value_ == 0; } +}; + +namespace boost{ + +template<> +struct has_nothrow_move +{ + static const bool value = true; +}; + +} //namespace boost{ + +////////////////////////////////////////////////////////////////////////////// +//A movable_throwable class +class movable_throwable +{ + BOOST_MOVABLE_BUT_NOT_COPYABLE(movable_throwable) + int value_; + + public: + movable_throwable() : value_(1){} + + //Move constructor and assignment + movable_throwable(BOOST_RV_REF(movable_throwable) m) + { value_ = m.value_; m.value_ = 0; } + + movable_throwable & operator=(BOOST_RV_REF(movable_throwable) m) + { value_ = m.value_; m.value_ = 0; return *this; } + + bool moved() const //Observer + { return !value_; } + + int value() const //Observer + { return value_; } +}; + + +////////////////////////////////////////////////////////////////////////////// +// Helper functions +movable function(movable m) +{ + return movable(boost::move_if_noexcept(m)); +} + +copy_movable function(copy_movable m) +{ + return copy_movable(boost::move_if_noexcept(m)); +} + +copy_movable_noexcept function(copy_movable_noexcept m) +{ + return copy_movable_noexcept(boost::move_if_noexcept(m)); +} + +movable_throwable function(movable_throwable m) +{ + return movable_throwable(boost::move_if_noexcept(m)); +} + +movable functionr(BOOST_RV_REF(movable) m) +{ + return movable(boost::move_if_noexcept(m)); +} + +movable function2(movable m) +{ + return boost::move_if_noexcept(m); +} + +BOOST_RV_REF(movable) function2r(BOOST_RV_REF(movable) m) +{ + return boost::move_if_noexcept(m); +} + +movable move_return_function2 () +{ + return movable(); +} + +movable move_return_function () +{ + movable m; + return (boost::move_if_noexcept(m)); +} + +#define BOOST_CHECK(x) if (!(x)) { return __LINE__; } + +int main() +{ + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + movable m3(function(movable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + movable m4(function(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + movable m3(functionr(movable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + movable m4(functionr(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + movable m3(function2(movable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + movable m4(function2(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + movable m3(function2r(movable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + movable m4(function2r(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + BOOST_CHECK(!m2.moved()); + movable m3(move_return_function()); + BOOST_CHECK(!m3.moved()); + } + { + movable m; + movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + BOOST_CHECK(!m2.moved()); + movable m3(move_return_function2()); + BOOST_CHECK(!m3.moved()); + } + + // copy_movable may throw during move, so it must be copied + { + copy_movable m; + copy_movable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(!m.moved()); + copy_movable m3(function(copy_movable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(!m2.moved()); + copy_movable m4(function(boost::move_if_noexcept(m3))); + BOOST_CHECK(!m3.moved()); + BOOST_CHECK(!m4.moved()); + } + + + // copy_movable_noexcept can not throw during move + { + copy_movable_noexcept m; + copy_movable_noexcept m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + copy_movable_noexcept m3(function(copy_movable_noexcept(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + copy_movable_noexcept m4(function(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + + // movable_throwable can not throw during move but it has no copy constructor + { + movable_throwable m; + movable_throwable m2(boost::move_if_noexcept(m)); + BOOST_CHECK(m.moved()); + movable_throwable m3(function(movable_throwable(boost::move_if_noexcept(m2)))); + BOOST_CHECK(m2.moved()); + movable_throwable m4(function(boost::move_if_noexcept(m3))); + BOOST_CHECK(m3.moved()); + BOOST_CHECK(!m4.moved()); + } + + return 0; +} + +#include