update nlohmann modernjson to v3.4 (with bson support)

5 files changed, 161 insertions, 51 deletions

diff --git a/include/lib/modernjson/detail/meta/cpp_future.hpp b/include/lib/modernjson/detail/meta/cpp_future.hpp
index fa7478b..948cd4f 100644
--- a/include/lib/modernjson/detail/meta/cpp_future.hpp
+++ b/include/lib/modernjson/detail/meta/cpp_future.hpp
@@ -59,5 +59,5 @@ struct static_const
 
 template<typename T>
 constexpr T static_const<T>::value;
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/meta/detected.hpp b/include/lib/modernjson/detail/meta/detected.hpp
index 78b25d5..8fb318a 100644
--- a/include/lib/modernjson/detail/meta/detected.hpp
+++ b/include/lib/modernjson/detail/meta/detected.hpp
@@ -52,5 +52,5 @@ using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
 template <class To, template <class...> class Op, class... Args>
 using is_detected_convertible =
     std::is_convertible<detected_t<Op, Args...>, To>;
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/meta/is_sax.hpp b/include/lib/modernjson/detail/meta/is_sax.hpp
index 63f9793..af63386 100644
--- a/include/lib/modernjson/detail/meta/is_sax.hpp
+++ b/include/lib/modernjson/detail/meta/is_sax.hpp
@@ -137,5 +137,5 @@ public:
       "Missing/invalid function: bool parse_error(std::size_t, const "
       "std::string&, const exception&)");
 };
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/meta/type_traits.hpp b/include/lib/modernjson/detail/meta/type_traits.hpp
index e5b6986..2f0af28 100644
--- a/include/lib/modernjson/detail/meta/type_traits.hpp
+++ b/include/lib/modernjson/detail/meta/type_traits.hpp
@@ -26,6 +26,15 @@ namespace detail
 // helpers //
 /////////////
 
+// Note to maintainers:
+//
+// Every trait in this file expects a non CV-qualified type.
+// The only exceptions are in the 'aliases for detected' section
+// (i.e. those of the form: decltype(T::member_function(std::declval<T>())))
+//
+// In this case, T has to be properly CV-qualified to constraint the function arguments
+// (e.g. to_json(BasicJsonType&, const T&))
+
 template<typename> struct is_basic_json : std::false_type {};
 
 NLOHMANN_BASIC_JSON_TPL_DECLARATION
@@ -65,6 +74,55 @@ using to_json_function = decltype(T::to_json(std::declval<Args>()...));
 template <typename T, typename... Args>
 using from_json_function = decltype(T::from_json(std::declval<Args>()...));
 
+template <typename T, typename U>
+using get_template_function = decltype(std::declval<T>().template get<U>());
+
+// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
+template <typename BasicJsonType, typename T, typename = void>
+struct has_from_json : std::false_type {};
+
+template <typename BasicJsonType, typename T>
+struct has_from_json<BasicJsonType, T,
+           enable_if_t<not is_basic_json<T>::value>>
+{
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+
+    static constexpr bool value =
+        is_detected_exact<void, from_json_function, serializer,
+        const BasicJsonType&, T&>::value;
+};
+
+// This trait checks if JSONSerializer<T>::from_json(json const&) exists
+// this overload is used for non-default-constructible user-defined-types
+template <typename BasicJsonType, typename T, typename = void>
+struct has_non_default_from_json : std::false_type {};
+
+template<typename BasicJsonType, typename T>
+struct has_non_default_from_json<BasicJsonType, T, enable_if_t<not is_basic_json<T>::value>>
+{
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+
+    static constexpr bool value =
+        is_detected_exact<T, from_json_function, serializer,
+        const BasicJsonType&>::value;
+};
+
+// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
+// Do not evaluate the trait when T is a basic_json type, to avoid template instantiation infinite recursion.
+template <typename BasicJsonType, typename T, typename = void>
+struct has_to_json : std::false_type {};
+
+template <typename BasicJsonType, typename T>
+struct has_to_json<BasicJsonType, T, enable_if_t<not is_basic_json<T>::value>>
+{
+    using serializer = typename BasicJsonType::template json_serializer<T, void>;
+
+    static constexpr bool value =
+        is_detected_exact<void, to_json_function, serializer, BasicJsonType&,
+        T>::value;
+};
+
+
 ///////////////////
 // is_ functions //
 ///////////////////
@@ -120,6 +178,30 @@ template <typename BasicJsonType, typename CompatibleObjectType>
 struct is_compatible_object_type
     : is_compatible_object_type_impl<BasicJsonType, CompatibleObjectType> {};
 
+template <typename BasicJsonType, typename ConstructibleObjectType,
+          typename = void>
+struct is_constructible_object_type_impl : std::false_type {};
+
+template <typename BasicJsonType, typename ConstructibleObjectType>
+struct is_constructible_object_type_impl <
+    BasicJsonType, ConstructibleObjectType,
+    enable_if_t<is_detected<mapped_type_t, ConstructibleObjectType>::value and
+    is_detected<key_type_t, ConstructibleObjectType>::value >>
+{
+    using object_t = typename BasicJsonType::object_t;
+
+    static constexpr bool value =
+        (std::is_constructible<typename ConstructibleObjectType::key_type, typename object_t::key_type>::value and
+         std::is_same<typename object_t::mapped_type, typename ConstructibleObjectType::mapped_type>::value) or
+        (has_from_json<BasicJsonType, typename ConstructibleObjectType::mapped_type>::value or
+         has_non_default_from_json<BasicJsonType, typename ConstructibleObjectType::mapped_type >::value);
+};
+
+template <typename BasicJsonType, typename ConstructibleObjectType>
+struct is_constructible_object_type
+    : is_constructible_object_type_impl<BasicJsonType,
+      ConstructibleObjectType> {};
+
 template <typename BasicJsonType, typename CompatibleStringType,
           typename = void>
 struct is_compatible_string_type_impl : std::false_type {};
@@ -134,9 +216,28 @@ struct is_compatible_string_type_impl <
         std::is_constructible<typename BasicJsonType::string_t, CompatibleStringType>::value;
 };
 
-template <typename BasicJsonType, typename CompatibleStringType>
+template <typename BasicJsonType, typename ConstructibleStringType>
 struct is_compatible_string_type
-    : is_compatible_string_type_impl<BasicJsonType, CompatibleStringType> {};
+    : is_compatible_string_type_impl<BasicJsonType, ConstructibleStringType> {};
+
+template <typename BasicJsonType, typename ConstructibleStringType,
+          typename = void>
+struct is_constructible_string_type_impl : std::false_type {};
+
+template <typename BasicJsonType, typename ConstructibleStringType>
+struct is_constructible_string_type_impl <
+    BasicJsonType, ConstructibleStringType,
+    enable_if_t<is_detected_exact<typename BasicJsonType::string_t::value_type,
+    value_type_t, ConstructibleStringType>::value >>
+{
+    static constexpr auto value =
+        std::is_constructible<ConstructibleStringType,
+        typename BasicJsonType::string_t>::value;
+};
+
+template <typename BasicJsonType, typename ConstructibleStringType>
+struct is_constructible_string_type
+    : is_constructible_string_type_impl<BasicJsonType, ConstructibleStringType> {};
 
 template <typename BasicJsonType, typename CompatibleArrayType, typename = void>
 struct is_compatible_array_type_impl : std::false_type {};
@@ -145,18 +246,61 @@ template <typename BasicJsonType, typename CompatibleArrayType>
 struct is_compatible_array_type_impl <
     BasicJsonType, CompatibleArrayType,
     enable_if_t<is_detected<value_type_t, CompatibleArrayType>::value and
-    is_detected<iterator_t, CompatibleArrayType>::value >>
+    is_detected<iterator_t, CompatibleArrayType>::value and
+// This is needed because json_reverse_iterator has a ::iterator type...
+// Therefore it is detected as a CompatibleArrayType.
+// The real fix would be to have an Iterable concept.
+    not is_iterator_traits<
+    std::iterator_traits<CompatibleArrayType>>::value >>
 {
-    // This is needed because json_reverse_iterator has a ::iterator type...
-    // Therefore it is detected as a CompatibleArrayType.
-    // The real fix would be to have an Iterable concept.
-    static constexpr bool value = not is_iterator_traits<std::iterator_traits<CompatibleArrayType>>::value;
+    static constexpr bool value =
+        std::is_constructible<BasicJsonType,
+        typename CompatibleArrayType::value_type>::value;
 };
 
 template <typename BasicJsonType, typename CompatibleArrayType>
 struct is_compatible_array_type
     : is_compatible_array_type_impl<BasicJsonType, CompatibleArrayType> {};
 
+template <typename BasicJsonType, typename ConstructibleArrayType, typename = void>
+struct is_constructible_array_type_impl : std::false_type {};
+
+template <typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type_impl <
+    BasicJsonType, ConstructibleArrayType,
+    enable_if_t<std::is_same<ConstructibleArrayType,
+    typename BasicJsonType::value_type>::value >>
+            : std::true_type {};
+
+template <typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type_impl <
+    BasicJsonType, ConstructibleArrayType,
+    enable_if_t<not std::is_same<ConstructibleArrayType,
+    typename BasicJsonType::value_type>::value and
+    is_detected<value_type_t, ConstructibleArrayType>::value and
+    is_detected<iterator_t, ConstructibleArrayType>::value and
+    is_complete_type<
+    detected_t<value_type_t, ConstructibleArrayType>>::value >>
+{
+    static constexpr bool value =
+        // This is needed because json_reverse_iterator has a ::iterator type,
+        // furthermore, std::back_insert_iterator (and other iterators) have a base class `iterator`...
+        // Therefore it is detected as a ConstructibleArrayType.
+        // The real fix would be to have an Iterable concept.
+        not is_iterator_traits <
+        std::iterator_traits<ConstructibleArrayType >>::value and
+
+        (std::is_same<typename ConstructibleArrayType::value_type, typename BasicJsonType::array_t::value_type>::value or
+         has_from_json<BasicJsonType,
+         typename ConstructibleArrayType::value_type>::value or
+         has_non_default_from_json <
+         BasicJsonType, typename ConstructibleArrayType::value_type >::value);
+};
+
+template <typename BasicJsonType, typename ConstructibleArrayType>
+struct is_constructible_array_type
+    : is_constructible_array_type_impl<BasicJsonType, ConstructibleArrayType> {};
+
 template <typename RealIntegerType, typename CompatibleNumberIntegerType,
           typename = void>
 struct is_compatible_integer_type_impl : std::false_type {};
@@ -184,40 +328,6 @@ struct is_compatible_integer_type
     : is_compatible_integer_type_impl<RealIntegerType,
       CompatibleNumberIntegerType> {};
 
-// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists
-template<typename BasicJsonType, typename T>
-struct has_from_json
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
-
-    static constexpr bool value =
-        is_detected_exact<void, from_json_function, serializer,
-        const BasicJsonType&, T&>::value;
-};
-
-// This trait checks if JSONSerializer<T>::from_json(json const&) exists
-// this overload is used for non-default-constructible user-defined-types
-template<typename BasicJsonType, typename T>
-struct has_non_default_from_json
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
-
-    static constexpr bool value =
-        is_detected_exact<T, from_json_function, serializer,
-        const BasicJsonType&>::value;
-};
-
-// This trait checks if BasicJsonType::json_serializer<T>::to_json exists
-template<typename BasicJsonType, typename T>
-struct has_to_json
-{
-    using serializer = typename BasicJsonType::template json_serializer<T, void>;
-
-    static constexpr bool value =
-        is_detected_exact<void, to_json_function, serializer, BasicJsonType&,
-        T>::value;
-};
-
 template <typename BasicJsonType, typename CompatibleType, typename = void>
 struct is_compatible_type_impl: std::false_type {};
 
@@ -233,5 +343,5 @@ struct is_compatible_type_impl <
 template <typename BasicJsonType, typename CompatibleType>
 struct is_compatible_type
     : is_compatible_type_impl<BasicJsonType, CompatibleType> {};
-}
-}
+}  // namespace detail
+}  // namespace nlohmann
diff --git a/include/lib/modernjson/detail/meta/void_t.hpp b/include/lib/modernjson/detail/meta/void_t.hpp
index 2528ea8..a256f85 100644
--- a/include/lib/modernjson/detail/meta/void_t.hpp
+++ b/include/lib/modernjson/detail/meta/void_t.hpp
@@ -9,5 +9,5 @@ template <typename ...Ts> struct make_void
     using type = void;
 };
 template <typename ...Ts> using void_t = typename make_void<Ts...>::type;
-}
-}
+} // namespace detail
+}  // namespace nlohmann