From f02990aebc4dfcc08570065586a2315aed367b90 Mon Sep 17 00:00:00 2001
From: Antony Polukhin <antoshkka@gmail.com>
Date: Wed, 4 Jun 2014 19:57:30 +0400
Subject: [PATCH 1/3] Added initial implementation of move_if_noexcept

---
 include/boost/move/traits.hpp  |  10 ++++
 include/boost/move/utility.hpp | 103 +++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

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 <boost/type_traits/has_trivial_destructor.hpp>
 #include <boost/type_traits/is_nothrow_move_constructible.hpp>
 #include <boost/type_traits/is_nothrow_move_assignable.hpp>
+#include <boost/type_traits/is_copy_constructible.hpp>
 #include <boost/move/detail/meta_utils.hpp>
 
 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
@@ -55,6 +56,15 @@ struct has_nothrow_move
 
 namespace move_detail {
 
+template <class T>
+struct has_nothrow_move_or_uncopyable
+    : public ::boost::move_detail::integral_constant
+      < bool
+      , has_nothrow_move<T>::value ||
+        !boost::is_copy_constructible<T>::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 964500e..33c861f 100644
--- a/include/boost/move/utility.hpp
+++ b/include/boost/move/utility.hpp
@@ -17,6 +17,7 @@
 #include <boost/move/detail/config_begin.hpp>
 #include <boost/move/core.hpp>
 #include <boost/move/detail/meta_utils.hpp>
+#include <boost/move/traits.hpp>
 
 #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
 
@@ -80,6 +81,56 @@
       return x;
    }
 
+   //////////////////////////////////////////////////////////////////////////////
+   //
+   //                            move_if_noexcept()
+   //
+   //////////////////////////////////////////////////////////////////////////////
+
+   template <class T>
+   inline typename ::boost::move_detail::enable_if_c
+      < enable_move_utility_emulation<T>::value && !has_move_emulation_enabled<T>::value, T&>::type
+         move_if_noexcept(T& x) BOOST_NOEXCEPT
+   {
+      return x;
+   }
+
+   template <class T>
+   inline typename ::boost::move_detail::enable_if_c
+      < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
+            && ::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, rv<T>&>::type
+         move_if_noexcept(T& x) BOOST_NOEXCEPT
+   {
+      return *static_cast<rv<T>* >(::boost::move_detail::addressof(x));
+   }
+
+   template <class T>
+   inline typename ::boost::move_detail::enable_if_c
+      < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
+            && ::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, rv<T>&>::type
+         move_if_noexcept(rv<T>& x) BOOST_NOEXCEPT
+   {
+      return x;
+   }
+
+   template <class T>
+   inline typename ::boost::move_detail::enable_if_c
+      < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
+            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::type
+         move_if_noexcept(T& x) BOOST_NOEXCEPT
+   {
+      return x;
+   }
+
+   template <class T>
+   inline typename ::boost::move_detail::enable_if_c
+      < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
+            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::type
+         move_if_noexcept(rv<T>& x) BOOST_NOEXCEPT
+   {
+      return x;
+   }
+
    }  //namespace boost
 
 #else    //#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
@@ -91,6 +142,7 @@
 
       using ::std::move;
       using ::std::forward;
+      using ::std::move_if_noexcept;
 
       }  //namespace boost
 
@@ -183,6 +235,57 @@
 
       #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
+         //! <i>::boost::rv<T> &</i> 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.
+         template <class T>
+         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 <class T>
+         inline typename ::boost::move_detail::enable_if_c
+           < ::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename remove_reference<T>::type&&>::type
+              move_if_noexcept(T& x) BOOST_NOEXCEPT
+         {
+           return ::boost::move(x);
+         }
+
+         template <class T>
+         inline typename ::boost::move_detail::enable_if_c
+           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename remove_reference<T>::type&>::type
+              move_if_noexcept(T& x) BOOST_NOEXCEPT
+         {
+           return x;
+         }
+
+      #else //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
+         template <class T>
+         inline typename ::boost::move_detail::enable_if_c
+           < ::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&&>::type
+              move_if_noexcept(T& x) BOOST_NOEXCEPT
+         {
+           return ::boost::move(x);
+         }
+
+         template <class T>
+         inline typename ::boost::move_detail::enable_if_c
+           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::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)

From 688c5726f80edbbb0f5240ed82915a8fc4be80e2 Mon Sep 17 00:00:00 2001
From: Antony Polukhin <antoshkka@gmail.com>
Date: Fri, 6 Jun 2014 12:43:34 +0400
Subject: [PATCH 2/3] Add tests for move_if_noexcept

---
 test/move_if_noexcept.cpp | 228 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 228 insertions(+)
 create mode 100644 test/move_if_noexcept.cpp

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 <boost/move/detail/config_begin.hpp>
+#include <boost/move/utility.hpp>
+#include "../example/movable.hpp"
+#include "../example/copymovable.hpp"
+#include <boost/static_assert.hpp>
+
+//////////////////////////////////////////////////////////////////////////////
+//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<copy_movable_noexcept>
+{
+   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 <boost/move/detail/config_end.hpp>

From c60351de0ff225a741e995ad1d0ed8b57be5458f Mon Sep 17 00:00:00 2001
From: Antony Polukhin <antoshkka@gmail.com>
Date: Mon, 23 Jun 2014 12:35:41 +0400
Subject: [PATCH 3/3] Fix move_if_noexcept: add const to reference

---
 include/boost/move/utility.hpp | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/include/boost/move/utility.hpp b/include/boost/move/utility.hpp
index 33c861f..80b2716 100644
--- a/include/boost/move/utility.hpp
+++ b/include/boost/move/utility.hpp
@@ -18,6 +18,7 @@
 #include <boost/move/core.hpp>
 #include <boost/move/detail/meta_utils.hpp>
 #include <boost/move/traits.hpp>
+#include <boost/type_traits/add_const.hpp>
 
 #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
 
@@ -89,7 +90,7 @@
 
    template <class T>
    inline typename ::boost::move_detail::enable_if_c
-      < enable_move_utility_emulation<T>::value && !has_move_emulation_enabled<T>::value, T&>::type
+      < enable_move_utility_emulation<T>::value && !has_move_emulation_enabled<T>::value, typename add_const<T>::type & >::type
          move_if_noexcept(T& x) BOOST_NOEXCEPT
    {
       return x;
@@ -116,7 +117,7 @@
    template <class T>
    inline typename ::boost::move_detail::enable_if_c
       < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
-            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::type
+            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename add_const<T>::type & >::type
          move_if_noexcept(T& x) BOOST_NOEXCEPT
    {
       return x;
@@ -125,7 +126,7 @@
    template <class T>
    inline typename ::boost::move_detail::enable_if_c
       < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value
-            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::type
+            && !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename add_const<T>::type & >::type
          move_if_noexcept(rv<T>& x) BOOST_NOEXCEPT
    {
       return x;
@@ -245,7 +246,8 @@
          //! in compilers with rvalue references. For other compilers converts T & into
          //! <i>::boost::rv<T> &</i> 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.
+         //! constructible or if it has no copy constructor. In all other cases const
+         //! reference would be returned
          template <class T>
          rvalue_reference move_if_noexcept(input_reference) noexcept;
 
@@ -262,7 +264,9 @@
 
          template <class T>
          inline typename ::boost::move_detail::enable_if_c
-           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename remove_reference<T>::type&>::type
+           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value,
+              typename add_const<typename remove_reference<T>::type>::type&
+           >::type
               move_if_noexcept(T& x) BOOST_NOEXCEPT
          {
            return x;
@@ -279,7 +283,7 @@
 
          template <class T>
          inline typename ::boost::move_detail::enable_if_c
-           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, T&>::type
+           < !::boost::move_detail::has_nothrow_move_or_uncopyable<T>::value, typename add_const<T>::type & >::type
               move_if_noexcept(T& x) BOOST_NOEXCEPT
          {
            return x;