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to_json and from_json takes both two arguments now

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the first is the basic_json type, the second the user-defined type
This commit is contained in:
Théo DELRIEU 2016-11-09 23:55:03 +01:00 committed by Théo DELRIEU
parent 837b81d672
commit 2bc685f6b4
2 changed files with 41 additions and 43 deletions
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49
src/json.hpp
View file

@ -155,22 +155,21 @@ void from_json();
struct to_json_fn struct to_json_fn
{ {
template <typename T> template <typename Json, typename T>
constexpr auto constexpr auto
operator()(T &&val) const noexcept(noexcept(to_json(std::forward<T>(val)))) operator()(Json&& j, T &&val) const noexcept(noexcept(to_json(std::forward<Json>(j), std::forward<T>(val))))
-> decltype(to_json(std::forward<T>(val))) -> decltype(to_json(std::forward<Json>(j), std::forward<T>(val)), void())
{ {
return to_json(std::forward<T>(val)); return to_json(std::forward<Json>(j), std::forward<T>(val));
} }
}; };
struct from_json_fn struct from_json_fn
{ {
template <typename T, typename Json> template <typename Json, typename T>
constexpr auto operator()(Json &&j, T &val) const constexpr auto operator()(Json &&j, T &val) const
noexcept(noexcept(from_json(std::forward<Json>(j), val))) noexcept(noexcept(from_json(std::forward<Json>(j), val)))
-> decltype(from_json(std::forward<Json>(j), val)) -> decltype(from_json(std::forward<Json>(j), val), void())
{ {
return from_json(std::forward<Json>(j), val); return from_json(std::forward<Json>(j), val);
} }
@ -219,28 +218,19 @@ inline namespace
template <typename = void, typename = void> template <typename = void, typename = void>
struct adl_serializer struct adl_serializer
{ {
template <typename T, typename Json, typename = enable_if_t<std::is_default_constructible<uncvref_t<T>>::value>> template <typename Json, typename T>
static auto from_json(Json&& j) -> uncvref_t<decltype(::nlohmann::from_json(std::forward<Json>(j), std::declval<T&>()), std::declval<T>())> static auto from_json(Json&& j, T& val) -> decltype(::nlohmann::from_json(std::forward<Json>(j), val), void())
{
uncvref_t<T> ret;
::nlohmann::from_json(std::forward<Json>(j), ret);
return ret;
}
template <typename T, typename Json>
static auto from_json(Json&& j, T& val) -> decltype(::nlohmann::from_json(std::forward<Json>(j), val))
{ {
::nlohmann::from_json(std::forward<Json>(j), val); ::nlohmann::from_json(std::forward<Json>(j), val);
} }
template <typename T> template <typename Json, typename T>
static auto to_json(T&& val) -> decltype(::nlohmann::to_json(std::forward<T>(val))) static auto to_json(Json& j, T&& val) -> decltype(::nlohmann::to_json(j, std::forward<T>(val)), void())
{ {
return ::nlohmann::to_json(std::forward<T>(val)); ::nlohmann::to_json(j, std::forward<T>(val));
} }
}; };
/*! /*!
@brief a class to store JSON values @brief a class to store JSON values
@ -1399,9 +1389,11 @@ class basic_json
} }
// constructor chosen when JSONSerializer::to_json exists for type T // constructor chosen when JSONSerializer::to_json exists for type T
template <typename T, typename = decltype(JSONSerializer<uncvref_t<T>>::to_json(std::declval<uncvref_t<T>>()))> template <typename T, typename = decltype(JSONSerializer<uncvref_t<T>>::to_json(std::declval<basic_json&>(), std::declval<uncvref_t<T>>()))>
explicit basic_json(T &&val) explicit basic_json(T &&val)
: basic_json(JSONSerializer<uncvref_t<T>>::to_json(std::forward<T>(val))) {} {
JSONSerializer<uncvref_t<T>>::to_json(*this, std::forward<T>(val));
}
/*! /*!
@brief create a string (explicit) @brief create a string (explicit)
@ -3072,11 +3064,14 @@ class basic_json
return get_impl(static_cast<ValueType*>(nullptr)); return get_impl(static_cast<ValueType*>(nullptr));
} }
template <typename ValueType, typename = enable_if_t<std::is_default_constructible<uncvref_t<ValueType>>::value, float>> template <typename ValueType, typename = decltype(JSONSerializer<uncvref_t<ValueType>>::from_json(std::declval<basic_json>(), std::declval<ValueType&>()))>
auto get() const -> remove_reference_t<decltype(JSONSerializer<uncvref_t<ValueType>>::from_json(*this, std::declval<ValueType&>()), std::declval<ValueType>())> auto get() const -> uncvref_t<ValueType>
{ {
uncvref_t<ValueType> ret; using type = uncvref_t<ValueType>;
JSONSerializer<uncvref_t<ValueType>>::from_json(*this, ret); 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; return ret;
} }

35
test/src/unit-udt.cpp
View file

@ -70,32 +70,31 @@ private:
// free to/from_json functions // free to/from_json functions
json to_json(empty_type) void to_json(json& j, empty_type)
{ {
return json::object(); j = json::object();
} }
json to_json(pod_type const& p) void to_json(json& j, pod_type const& p)
{ {
return {{"a", p.a}, {"b", p.b}, {"c", p.c}}; j = json{{"a", p.a}, {"b", p.b}, {"c", p.c}};
} }
json to_json(bit_more_complex_type const& p) void to_json(json& j, bit_more_complex_type const& p)
{ {
using nlohmann::to_json; j = json{{"a", json(p.a)}, {"b", json(p.b)}, {"c", p.c}};
return json{{"a", to_json(p.a)}, {"b", to_json(p.b)}, {"c", p.c}};
} }
template <typename T> template <typename T>
json to_json(optional_type<T> const& opt) void to_json(json& j, optional_type<T> const& opt)
{ {
using nlohmann::to_json;
if (!opt) if (!opt)
return nullptr; j = nullptr;
return json(*opt); else
j = json(*opt);
} }
void from_json(json const&j, empty_type& t) void from_json(json const& j, empty_type& t)
{ {
assert(j.empty()); assert(j.empty());
t = empty_type{}; t = empty_type{};
@ -292,7 +291,8 @@ TEST_CASE("to_json free function", "[udt]")
auto const e = udt::pod_type{42, 42, 42}; auto const e = udt::pod_type{42, 42, 42};
auto const expected = json{{"a", 42}, {"b", 42}, {"c", 42}}; auto const expected = json{{"a", 42}, {"b", 42}, {"c", 42}};
auto const j = nlohmann::to_json(e); json j;
nlohmann::to_json(j, e);
CHECK(j == expected); CHECK(j == expected);
} }
@ -303,7 +303,8 @@ TEST_CASE("to_json free function", "[udt]")
auto const expected = json{{"a", {{"a", 42}, {"b", 42}, {"c", 42}}}, auto const expected = json{{"a", {{"a", 42}, {"b", 42}, {"c", 42}}},
{"b", {{"a", 41}, {"b", 41}, {"c", 41}}}, {"b", {{"a", 41}, {"b", 41}, {"c", 41}}},
{"c", "forty"}}; {"c", "forty"}};
auto const j = nlohmann::to_json(e); json j;
nlohmann::to_json(j, e);
CHECK(j == expected); CHECK(j == expected);
} }
@ -314,7 +315,8 @@ TEST_CASE("to_json free function", "[udt]")
udt::optional_type<udt::pod_type> o; udt::optional_type<udt::pod_type> o;
json expected; json expected;
auto const j = nlohmann::to_json(o); json j;
nlohmann::to_json(j, o);
CHECK(expected == j); CHECK(expected == j);
} }
@ -323,7 +325,8 @@ TEST_CASE("to_json free function", "[udt]")
udt::optional_type<udt::pod_type> o{{42, 42, 42}}; udt::optional_type<udt::pod_type> o{{42, 42, 42}};
auto const expected = json{{"a", 42}, {"b", 42}, {"c", 42}}; auto const expected = json{{"a", 42}, {"b", 42}, {"c", 42}};
auto const j = nlohmann::to_json(o); json j;
nlohmann::to_json(j, o);
CHECK(expected == j); CHECK(expected == j);
} }
} }