Adding MPark's variant (V1.4.0) to HPX

- adding serialization support for hpx::util::variant
- flyby: add support for skipping whole files to inspect (without modifying them)

hpx/runtime/serialization/variant.hpp

@@ -1,100 +1,52 @@
-//  copyright (c) 2005
-//  troy d. straszheim <[email protected]>
-//  http://www.resophonic.com
 //  Copyright (c) 2015 Anton Bikineev
+//  Copyright (c) 2017-2019 Hartmut Kaiser
 //
 //  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)
 
-#ifndef HPX_SERIALIZATION_VARIANT_HPP
-#define HPX_SERIALIZATION_VARIANT_HPP
+#if !defined(HPX_DATASTRUCTURES_VARIANT_SERIALIZATION_HPP)
+#define HPX_DATASTRUCTURES_VARIANT_SERIALIZATION_HPP
 
 #include <hpx/config.hpp>
-#include <hpx/runtime/serialization/serialization_fwd.hpp>
-#include <hpx/errors.hpp>
+#include <hpx/datastructures/variant.hpp>
 
-#include <boost/variant.hpp>
+#include <hpx/runtime/serialization/serialization_fwd.hpp>
+#include <hpx/runtime/serialization/boost_variant.hpp>
+#include <hpx/errors/throw_exception.hpp>
 
+#include <cstddef>
 #include <utility>
 
 namespace hpx { namespace serialization
 {
-    struct variant_save_visitor : boost::static_visitor<>
-    {
-        variant_save_visitor(output_archive& ar)
-          : m_ar(ar)
-        {}
-
-        template <typename T>
-        void operator()(T const& value) const
-        {
-            m_ar << value;
-        }
-
-    private:
-        output_archive & m_ar;
-    };
-
-    template <typename ... Ts>
-    struct variant_impl;
-
-    template <typename T, typename ... Ts>
-    struct variant_impl<T, Ts...>
-    {
-        template <typename V>
-        static void load(input_archive& ar, int which, V& v)
-        {
-            if (which == 0)
-            {
-            // note: A non-intrusive implementation (such as this one)
-            // necessary has to copy the value.  This wouldn't be necessary
-            // with an implementation that de-serialized to the address of the
-            // aligned storage included in the variant.
-                T value;
-                ar >> value;
-                v = std::move(value);
-                return;
-            }
-            variant_impl<Ts...>::load(ar, which - 1, v);
-        }
-    };
-
-    template <>
-    struct variant_impl<>
-    {
-        template <typename V>
-        static void load(input_archive& /*ar*/, int /*which*/, V& /*v*/)
-        {
-        }
-    };
-
-    template <typename ... T>
-    void save(output_archive& ar, boost::variant<T...> const& v, unsigned)
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename... Ts>
+    void save(output_archive& ar, hpx::util::variant<Ts...> const& v, unsigned)
     {
-        int which = v.which();
+        std::size_t which = v.index();
         ar << which;
-        variant_save_visitor visitor(ar);
-        v.apply_visitor(visitor);
+        detail::variant_save_visitor visitor(ar);
+        hpx::util::visit(visitor, v);
     }
 
-    template <typename ... T>
-    void load(input_archive& ar, boost::variant<T...>& v, unsigned)
+    template <typename... Ts>
+    void load(input_archive& ar, hpx::util::variant<Ts...>& v, unsigned)
     {
-        int which;
+        std::size_t which;
         ar >> which;
-        if (which >= static_cast<int>(sizeof...(T)))
+        if (which >= sizeof...(Ts))
         {
             // this might happen if a type was removed from the list of variant
             // types
             HPX_THROW_EXCEPTION(serialization_error
               , "load<Archive, Variant, version>"
               , "type was removed from the list of variant types");
         }
-        variant_impl<T...>::load(ar, which, v);
+        detail::variant_impl<Ts...>::load(ar, which, v);
     }
 
     HPX_SERIALIZATION_SPLIT_FREE_TEMPLATE(
-        (template<typename ... T>), (boost::variant<T...>));
+        (template <typename ... Ts>), (hpx::util::variant<Ts...>));
 }}
 
-#endif //HPX_SERIALIZATION_VARIANT_HPP
+#endif

libs/datastructures/CMakeLists.txt

@@ -8,7 +8,9 @@ cmake_minimum_required(VERSION 3.3.2 FATAL_ERROR)
 set(datastructures_headers
   hpx/datastructures/tuple.hpp
   hpx/datastructures/optional.hpp
+  hpx/datastructures/variant.hpp
   hpx/datastructures/detail/pack.hpp
+  hpx/datastructures/detail/variant.hpp
 )
 
 set(datastructures_compat_headers
@@ -27,6 +29,7 @@ add_hpx_module(datastructures
   GLOBAL_HEADER_GEN ON
   EXCLUDE_FROM_GLOBAL_HEADER
     "hpx/datastructures/detail/pack.hpp"
+    "hpx/datastructures/detail/variant.hpp"
   SOURCES ${datastructures_sources}
   HEADERS ${datastructures_headers}
   COMPAT_HEADERS ${datastructures_compat_headers}

libs/datastructures/include/hpx/datastructures/detail/hpx-no-inspect-files

@@ -0,0 +1 @@
+variant.hpp