Ticket #10882: boost-1.57.0-fix-boost-variant-ambiguous-call-to-swap-boost-trac-10882.patch

boost/move/adl_move_swap.hpp

@@ +1 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright 2007, 2008 Steven Watanabe, Joseph Gauterin, Niels Dekker
+// (C) Copyright Ion Gaztanaga 2005-2013. 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/container for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_MOVE_ADL_MOVE_SWAP_HPP
+#define BOOST_MOVE_ADL_MOVE_SWAP_HPP
+
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#  pragma once
+#endif
+
+//Based on Boost.Core's swap.
+//Many thanks to Steven Watanabe, Joseph Gauterin and Niels Dekker.
+
+#include <boost/config.hpp>
+#include <cstddef> //for std::size_t
+
+//Try to avoid including <algorithm>, as it's quite big
+#if defined(_MSC_VER) && defined(BOOST_DINKUMWARE_STDLIB)
+   #include <utility>   //Dinkum libraries define std::swap in utility which is lighter than algorithm
+#elif defined(BOOST_GNU_STDLIB)
+   //For non-GCC compilers, where GNUC version is not very reliable, or old GCC versions
+   //use the good old stl_algobase header, which is quite lightweight
+   #if !defined(BOOST_GCC) || ((__GNUC__ < 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ < 3)))
+      #include <bits/stl_algobase.h>
+   #elif (__GNUC__ == 4) && (__GNUC_MINOR__ == 3)
+      //In GCC 4.3 a tiny stl_move.h was created with swap and move utilities
+      #include <bits/stl_move.h>
+   #else
+      //In GCC 4.4 stl_move.h was renamed to move.h
+      #include <bits/move.h>
+   #endif
+#elif defined(_LIBCPP_VERSION)
+   #include <type_traits>  //The initial import of libc++ defines std::swap and still there
+#elif __cplusplus >= 201103L
+   #include <utility>    //Fallback for C++ >= 2011
+#else
+   #include <algorithm>  //Fallback for C++98/03
+#endif
+
+#include <boost/move/utility_core.hpp> //for boost::move
+
+#if !defined(BOOST_MOVE_DOXYGEN_INVOKED)
+
+#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+namespace boost_move_member_swap {
+
+struct dont_care
+{
+   dont_care(...);
+};
+
+struct private_type
+{
+   static private_type p;
+   private_type const &operator,(int) const;
+};
+
+typedef char yes_type;            
+struct no_type{ char dummy[2]; }; 
+
+template<typename T>
+no_type is_private_type(T const &);
+
+yes_type is_private_type(private_type const &);
+
+template <typename Type>
+class has_member_function_named_swap
+{
+   struct BaseMixin
+   {
+      void swap();
+   };
+
+   struct Base : public Type, public BaseMixin { Base(); };
+   template <typename T, T t> class Helper{};
+
+   template <typename U>
+   static no_type deduce(U*, Helper<void (BaseMixin::*)(), &U::swap>* = 0);
+   static yes_type deduce(...);
+
+   public:
+   static const bool value = sizeof(yes_type) == sizeof(deduce((Base*)(0)));
+};
+
+template<typename Fun, bool HasFunc>
+struct has_member_swap_impl
+{
+   static const bool value = false;
+};
+
+template<typename Fun>
+struct has_member_swap_impl<Fun, true>
+{
+   struct FunWrap : Fun
+   {
+      FunWrap();
+
+      using Fun::swap;
+      private_type swap(dont_care) const;
+   };
+
+   static Fun &declval_fun();
+   static FunWrap declval_wrap();
+
+   static bool const value =
+      sizeof(no_type) == sizeof(is_private_type( (declval_wrap().swap(declval_fun()), 0)) );
+};
+
+template<typename Fun>
+struct has_member_swap : public has_member_swap_impl
+      <Fun, has_member_function_named_swap<Fun>::value>
+{};
+
+}  //namespace boost_move_member_swap
+
+namespace boost_move_adl_swap{
+
+template<class P1, class P2, bool = P1::value>
+struct and_op_impl
+{  static const bool value = false; };
+
+template<class P1, class P2>
+struct and_op_impl<P1, P2, true>
+{  static const bool value = P2::value;   };
+
+template<class P1, class P2>
+struct and_op
+   : and_op_impl<P1, P2>
+{};
+
+//////
+
+template<class P1, class P2, bool = P1::value>
+struct and_op_not_impl
+{  static const bool value = false; };
+
+template<class P1, class P2>
+struct and_op_not_impl<P1, P2, true>
+{  static const bool value = !P2::value;   };
+
+template<class P1, class P2>
+struct and_op_not
+   : and_op_not_impl<P1, P2>
+{};
+
+template<class T>
+void swap_proxy(T& x, T& y, typename boost::move_detail::enable_if_c<!boost::move_detail::has_move_emulation_enabled_impl<T>::value>::type* = 0)
+{
+   //use std::swap if argument dependent lookup fails
+   //Use using directive ("using namespace xxx;") instead as some older compilers
+   //don't do ADL with using declarations ("using ns::func;").
+   using namespace std;
+   swap(x, y);
+}
+
+template<class T>
+void swap_proxy(T& x, T& y
+               , typename boost::move_detail::enable_if< and_op_not_impl<boost::move_detail::has_move_emulation_enabled_impl<T>
+                                                                        , boost_move_member_swap::has_member_swap<T> >
+                                                       >::type* = 0)
+{  T t(::boost::move(x)); x = ::boost::move(y); y = ::boost::move(t);  }
+
+template<class T>
+void swap_proxy(T& x, T& y
+               , typename boost::move_detail::enable_if< and_op_impl< boost::move_detail::has_move_emulation_enabled_impl<T>
+                                                                    , boost_move_member_swap::has_member_swap<T> >
+                                                       >::type* = 0)
+{  x.swap(y);  }
+
+}  //namespace boost_move_adl_swap{
+
+#else
+
+namespace boost_move_adl_swap{
+
+template<class T>
+void swap_proxy(T& x, T& y)
+{
+   using std::swap;
+   swap(x, y);
+}
+
+}  //namespace boost_move_adl_swap{
+
+#endif   //#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
+
+namespace boost_move_adl_swap{
+
+template<class T, std::size_t N>
+void swap_proxy(T (& x)[N], T (& y)[N])
+{
+   for (std::size_t i = 0; i < N; ++i){
+      ::boost_move_adl_swap::swap_proxy(x[i], y[i]);
+   }
+}
+
+}  //namespace boost_move_adl_swap {
+
+#endif   //!defined(BOOST_MOVE_DOXYGEN_INVOKED)
+
+namespace boost{
+
+//! Exchanges the values of a and b, using Argument Dependent Lookup (ADL) to select a
+//! specialized swap function if available. If no specialized swap function is available,
+//! std::swap is used.
+//!
+//! <b>Exception</b>: If T uses Boost.Move's move emulation and the compiler has
+//! no rvalue references then:
+//!
+//!   -  If T has a <code>T::swap(T&)</code> member, that member is called.
+//!   -  Otherwise a move-based swap is called, equivalent to: 
+//!      <code>T t(::boost::move(x)); x = ::boost::move(y); y = ::boost::move(t);</code>.
+template<class T>
+void adl_move_swap(T& x, T& y)
+{
+   ::boost_move_adl_swap::swap_proxy(x, y);
+}
+
+}  //namespace boost{
+
+#endif   //#ifndef BOOST_MOVE_ADL_MOVE_SWAP_HPP

boost/variant/detail/move.hpp

@@ -5 +5 @@
 //
 //  Copyright (c) 2002-2003 Eric Friedman
 //  Copyright (c) 2002 by Andrei Alexandrescu
-//  Copyright (c) 2013 Antony Polukhin
+//  Copyright (c) 2013-2014 Antony Polukhin
 //
 //  Use, modification and distribution are subject to the
 //  Boost Software License, Version 1.0. (See accompanying file
@@ -26 +26 @@
 #include "boost/config.hpp"
 #include "boost/detail/workaround.hpp"
 #include "boost/move/move.hpp"
+#include "boost/move/adl_move_swap.hpp"
 
 namespace boost { namespace detail { namespace variant {
 
@@ -38 +39 @@
 // types and on non-conforming compilers.
 //
 
-namespace move_swap_fallback {
-
-template <typename T1, typename T2>
-inline void swap(T1& lhs, T2& rhs)
-{
-    T1 tmp( boost::detail::variant::move(lhs) );
-    lhs = boost::detail::variant::move(rhs);
-    rhs = boost::detail::variant::move(tmp);
-}
-
-} // namespace move_swap_fallback
-
 template <typename T>
 inline void move_swap(T& lhs, T& rhs)
 {
-#if defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)
-    move_swap_fallback::swap(lhs, rhs);
-#else
-    using move_swap_fallback::swap;
-    swap(lhs, rhs);
-#endif
+    ::boost::adl_move_swap(lhs, rhs);
 }
 
 }}} // namespace boost::detail::variant