APT service serialization

src/common/serialization/optional.h

@@ -0,0 +1,91 @@
+#pragma once
+
+#include <boost/config.hpp>
+
+#include <boost/archive/detail/basic_iarchive.hpp>
+
+#include <optional>
+#include <boost/move/utility_core.hpp>
+
+#include <boost/serialization/item_version_type.hpp>
+#include <boost/serialization/split_free.hpp>
+#include <boost/serialization/level.hpp>
+#include <boost/serialization/nvp.hpp>
+#include <boost/serialization/version.hpp>
+#include <boost/type_traits/is_pointer.hpp>
+#include <boost/serialization/detail/stack_constructor.hpp>
+#include <boost/serialization/detail/is_default_constructible.hpp>
+#include <boost/serialization/force_include.hpp>
+
+// function specializations must be defined in the appropriate
+// namespace - boost::serialization
+namespace boost {
+namespace serialization {
+
+template<class Archive, class T>
+void save(
+    Archive & ar,
+    const std::optional< T > & t,
+    const unsigned int /*version*/
+){
+    // It is an inherent limitation to the serialization of optional.hpp
+    // that the underlying type must be either a pointer or must have a
+    // default constructor.  It's possible that this could change sometime
+    // in the future, but for now, one will have to work around it.  This can
+    // be done by serialization the optional<T> as optional<T *>
+    #if ! defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
+        BOOST_STATIC_ASSERT(
+            boost::serialization::detail::is_default_constructible<T>::value
+            || boost::is_pointer<T>::value
+        );
+    #endif
+    const bool tflag = t.has_value();
+    ar << boost::serialization::make_nvp("initialized", tflag);
+    if (tflag){
+        ar << boost::serialization::make_nvp("value", *t);
+    }
+}
+
+template<class Archive, class T>
+void load(
+    Archive & ar,
+    std::optional< T > & t,
+    const unsigned int version
+){
+    bool tflag;
+    ar >> boost::serialization::make_nvp("initialized", tflag);
+    if(! tflag){
+        t.reset();
+        return;
+    }
+
+    if(0 == version){
+        boost::serialization::item_version_type item_version(0);
+        boost::archive::library_version_type library_version(
+            ar.get_library_version()
+        );
+        if(boost::archive::library_version_type(3) < library_version){
+            ar >> BOOST_SERIALIZATION_NVP(item_version);
+        }
+    }
+    if(! t.has_value())
+        t = T();
+    ar >> boost::serialization::make_nvp("value", *t);
+}
+
+template<class Archive, class T>
+void serialize(
+    Archive & ar,
+    std::optional< T > & t,
+    const unsigned int version
+){
+    boost::serialization::split_free(ar, t, version);
+}
+
+template<class T>
+struct version<std::optional<T> > {
+    BOOST_STATIC_CONSTANT(int, value = 1);
+};
+
+} // serialization
+} // boost