mirror of
https://github.com/nlohmann/json.git
synced 2026-10-15 18:57:13 +00:00
Move elements when converting rvalue containers to JSON (#5837)
* Move elements when converting rvalue containers to JSON Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Simplify the rvalue to_json traits Use negation<disjunction<...>> instead of a conjunction of negations and keep the template argument lists compact (astyle only keeps the spaced '< ... >' form when it is written that way). Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann authored and 
GitHub committed
1 parent
6ba53e63dd
commit
ca7740fef2
5 files changed
+467
-1
No files matched your search
@@ -167,6 +167,17 @@ struct external_constructor<value_t::array>
|
||||
j.replace_value(value_t::array, value);
|
||||
}
|
||||
|
||||
/// an rvalue container: move its elements
|
||||
template<typename BasicJsonType, typename CompatibleArrayType>
|
||||
static void construct_moving(BasicJsonType& j, CompatibleArrayType& arr)
|
||||
{
|
||||
using std::begin;
|
||||
using std::end;
|
||||
|
||||
const typename BasicJsonType::json_value value(j.template create<typename BasicJsonType::array_t>(std::make_move_iterator(begin(arr)), std::make_move_iterator(end(arr))));
|
||||
j.replace_value(value_t::array, value);
|
||||
}
|
||||
|
||||
template<typename BasicJsonType>
|
||||
static void construct(BasicJsonType& j, const std::vector<bool>& arr)
|
||||
{
|
||||
@@ -217,6 +228,17 @@ struct external_constructor<value_t::object>
|
||||
j.replace_value(value_t::object, value);
|
||||
}
|
||||
|
||||
/// an rvalue container: move its values
|
||||
template<typename BasicJsonType, typename CompatibleObjectType>
|
||||
static void construct_moving(BasicJsonType& j, CompatibleObjectType& obj)
|
||||
{
|
||||
using std::begin;
|
||||
using std::end;
|
||||
|
||||
const typename BasicJsonType::json_value value(j.template create<typename BasicJsonType::object_t>(std::make_move_iterator(begin(obj)), std::make_move_iterator(end(obj))));
|
||||
j.replace_value(value_t::object, value);
|
||||
}
|
||||
|
||||
template < typename BasicJsonType, typename CompatibleObjectType,
|
||||
enable_if_t < !std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int > = 0 >
|
||||
static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
|
||||
@@ -354,6 +376,66 @@ inline void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
|
||||
external_constructor<value_t::array>::construct(j, arr);
|
||||
}
|
||||
|
||||
// types that have a dedicated to_json overload and must not be treated as generic containers
|
||||
template<typename T>
|
||||
struct has_dedicated_to_json : std::false_type {};
|
||||
|
||||
#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
|
||||
template<>
|
||||
struct has_dedicated_to_json<std_fs::path> : std::true_type {};
|
||||
#endif
|
||||
|
||||
#if defined(__cpp_lib_char8_t)
|
||||
template<typename Tr, typename Allocator>
|
||||
struct has_dedicated_to_json<std::basic_string<char8_t, Tr, Allocator>> : std::true_type {};
|
||||
#endif
|
||||
|
||||
#if JSON_HAS_RANGE_VIEW_CONVERSION
|
||||
template<typename T>
|
||||
struct is_range_view_type : is_compatible_range_view<T> {};
|
||||
#else
|
||||
template<typename T>
|
||||
struct is_range_view_type : std::false_type {};
|
||||
#endif
|
||||
|
||||
#if JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
|
||||
template<typename T>
|
||||
struct is_enum_keyed_map_type : is_enum_keyed_map<T> {};
|
||||
#else
|
||||
template<typename T>
|
||||
struct is_enum_keyed_map_type : std::false_type {};
|
||||
#endif
|
||||
|
||||
// rvalue (non-const) container: the generic to_json takes its elements by move
|
||||
template<typename T>
|
||||
using is_movable_container_rvalue = negation<disjunction<
|
||||
std::is_lvalue_reference<T>,
|
||||
std::is_const<T>,
|
||||
has_dedicated_to_json<T>,
|
||||
is_basic_json<T>,
|
||||
is_range_view_type<T>,
|
||||
is_enum_keyed_map_type<T>,
|
||||
std::is_same<T, std::vector<bool>>>>;
|
||||
|
||||
// rvalue array-like containers
|
||||
template<typename BasicJsonType, typename T>
|
||||
using is_rvalue_array_to_json = conjunction<is_movable_container_rvalue<T>,
|
||||
is_compatible_array_type<BasicJsonType, T>,
|
||||
negation<disjunction<
|
||||
std::is_same<T, typename BasicJsonType::array_t>,
|
||||
std::is_same<T, typename BasicJsonType::binary_t>,
|
||||
is_compatible_object_type<BasicJsonType, T>,
|
||||
is_compatible_string_type<BasicJsonType, T>,
|
||||
is_compatible_binary_type<BasicJsonType, T>>>>;
|
||||
|
||||
// rvalue containers: their elements are moved instead of copied
|
||||
template<typename BasicJsonType, typename CompatibleArrayType,
|
||||
enable_if_t<is_rvalue_array_to_json<BasicJsonType, CompatibleArrayType>::value, int> = 0>
|
||||
inline void to_json(BasicJsonType& j, CompatibleArrayType && arr)
|
||||
{
|
||||
external_constructor<value_t::array>::construct_moving(j, arr);
|
||||
}
|
||||
|
||||
#if JSON_HAS_RANGE_VIEW_CONVERSION
|
||||
template < typename BasicJsonType, typename T,
|
||||
enable_if_t < is_compatible_range_view<std::remove_cvref_t<T>>::value
|
||||
@@ -427,6 +509,19 @@ inline void to_json(BasicJsonType& j, const EnumKeyedMap& map)
|
||||
}
|
||||
#endif
|
||||
|
||||
// rvalue object-like containers
|
||||
template<typename BasicJsonType, typename T>
|
||||
using is_rvalue_object_to_json = conjunction<is_movable_container_rvalue<T>,
|
||||
negation<std::is_same<T, typename BasicJsonType::object_t>>,
|
||||
is_compatible_object_type<BasicJsonType, T>>;
|
||||
|
||||
template<typename BasicJsonType, typename CompatibleObjectType,
|
||||
enable_if_t<is_rvalue_object_to_json<BasicJsonType, CompatibleObjectType>::value, int> = 0>
|
||||
inline void to_json(BasicJsonType& j, CompatibleObjectType && obj)
|
||||
{
|
||||
external_constructor<value_t::object>::construct_moving(j, obj);
|
||||
}
|
||||
|
||||
template<typename BasicJsonType>
|
||||
inline void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
|
||||
{
|
||||
|
||||
Reference in new issue
Block a user