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add basic test for custom serializer

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This commit is contained in:
Théo DELRIEU 2016-11-15 14:22:12 +01:00
parent 2bc685f6b4
commit 178441cdfd
2 changed files with 107 additions and 11 deletions
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62
src/json.hpp
View file

@ -150,6 +150,38 @@ struct has_mapped_type
std::is_integral<decltype(detect(std::declval<T>()))>::value;
};
template <template <typename, typename> class JSONSerializer, typename Json,
typename T>
struct has_from_json
{
private:
template <typename U, typename = decltype(uncvref_t<U>::from_json(
std::declval<Json>(), std::declval<T &>()))>
static int detect(U &&);
static void detect(...);
public:
static constexpr bool value = std::is_integral<decltype(
detect(std::declval<JSONSerializer<T, void>>()))>::value;
};
template <template <typename, typename> class JSONSerializer, typename Json,
typename T>
struct has_to_json
{
private:
template <typename U, typename = decltype(uncvref_t<U>::to_json(
std::declval<Json &>(), std::declval<T>()))>
static int detect(U &&);
static void detect(...);
public:
static constexpr bool value = std::is_integral<decltype(
detect(std::declval<JSONSerializer<T, void>>()))>::value;
};
void to_json();
void from_json();
@ -1389,7 +1421,8 @@ class basic_json
}
// constructor chosen when JSONSerializer::to_json exists for type T
template <typename T, typename = decltype(JSONSerializer<uncvref_t<T>>::to_json(std::declval<basic_json&>(), std::declval<uncvref_t<T>>()))>
template <typename T, typename = typename std::enable_if<detail::has_to_json<
JSONSerializer, basic_json, uncvref_t<T>>::value>::type>
explicit basic_json(T &&val)
{
JSONSerializer<uncvref_t<T>>::to_json(*this, std::forward<T>(val));
@ -3057,19 +3090,26 @@ class basic_json
@since version 1.0.0
*/
template<typename ValueType, typename std::enable_if<
not std::is_pointer<ValueType>::value, int>::type = 0>
auto get() const -> decltype(this->get_impl(static_cast<ValueType*>(nullptr)))
{
return get_impl(static_cast<ValueType*>(nullptr));
template <typename ValueType,
typename std::enable_if<
not std::is_pointer<ValueType>::value and
not detail::has_from_json<JSONSerializer, basic_json,
uncvref_t<ValueType>>::value,
int>::type = 0>
auto get() const
-> decltype(this->get_impl(static_cast<ValueType *>(nullptr))) {
return get_impl(static_cast<ValueType *>(nullptr));
}
template <typename ValueType, typename = decltype(JSONSerializer<uncvref_t<ValueType>>::from_json(std::declval<basic_json>(), std::declval<ValueType&>()))>
auto get() const -> uncvref_t<ValueType>
{
template <typename ValueType,
typename = enable_if_t<detail::has_from_json<
JSONSerializer, basic_json, uncvref_t<ValueType>>::value>>
auto get() const -> uncvref_t<ValueType> {
using type = uncvref_t<ValueType>;
static_assert(std::is_default_constructible<type>::value && std::is_copy_constructible<type>::value,
"user-defined types must be DefaultConstructible and CopyConstructible when used with get");
static_assert(std::is_default_constructible<type>::value &&
std::is_copy_constructible<type>::value,
"user-defined types must be DefaultConstructible and "
"CopyConstructible when used with get");
type ret;
JSONSerializer<type>::from_json(*this, ret);
return ret;

56
test/src/unit-udt.cpp
View file

@ -379,3 +379,59 @@ TEST_CASE("from_json free function", "[udt]")
}
}
}
// custom serializer, uses adl by default
template <typename T, typename = void>
struct my_serializer;
template<>
struct my_serializer<udt::pod_type>
{
template <typename Json>
static void from_json(Json const& j, udt::pod_type& val)
{
nlohmann::from_json(j, val);
}
template <typename Json>
static void to_json(Json& j, udt::pod_type const& val)
{
nlohmann::to_json(j, val);
}
};
using my_json = nlohmann::basic_json<std::map, std::vector, std::string, bool,
std::int64_t, std::uint64_t, double,
std::allocator, my_serializer>;
namespace udt
{
void to_json(my_json& j, pod_type const& val)
{
j = my_json{{"a", val.a}, {"b", val.b}, {"c", val.c}};
}
void from_json(my_json const& j, pod_type& val)
{
val = {j["a"].get<int>(), j["b"].get<char>(), j["c"].get<short>()};
}
}
TEST_CASE("custom serializer")
{
SECTION("default use works like default serializer")
{
udt::pod_type pod{1, 2, 3};
auto const j = my_json{pod};
auto const j2 = json{pod};
CHECK(j.dump() == j2.dump());
auto const pod2 = j.get<udt::pod_type>();
auto const pod3 = j2.get<udt::pod_type>();
CHECK(pod2 == pod3);
CHECK(pod2 == pod);
}
}