make to_json SFINAE-correct

This commit is contained in:
Théo DELRIEU 2018-09-06 16:08:01 +02:00
parent f7c8a2145a
commit f7971f04a5
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GPG key ID: A5A505438C20539A
3 changed files with 22 additions and 58 deletions

View file

@ -35,9 +35,11 @@ struct adl_serializer
@param[in,out] j JSON value to write to
@param[in] val value to read from
*/
template<typename BasicJsonType, typename ValueType>
static void to_json(BasicJsonType& j, ValueType&& val) noexcept(
template <typename BasicJsonType, typename ValueType>
static auto to_json(BasicJsonType& j, ValueType&& val) noexcept(
noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
-> decltype(::nlohmann::to_json(j, std::forward<ValueType>(val)),
void())
{
::nlohmann::to_json(j, std::forward<ValueType>(val));
}

View file

@ -286,9 +286,12 @@ void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
external_constructor<value_t::object>::construct(j, std::move(obj));
}
template<typename BasicJsonType, typename T, std::size_t N,
enable_if_t<not std::is_constructible<typename BasicJsonType::string_t, T (&)[N]>::value, int> = 0>
void to_json(BasicJsonType& j, T (&arr)[N])
template <
typename BasicJsonType, typename T, std::size_t N,
enable_if_t<not std::is_constructible<typename BasicJsonType::string_t,
const T (&)[N]>::value,
int> = 0 >
void to_json(BasicJsonType& j, const T (&arr)[N])
{
external_constructor<value_t::array>::construct(j, arr);
}
@ -321,35 +324,12 @@ void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
struct to_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(BasicJsonType& j, T&& val, priority_tag<1> /*unused*/) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
auto operator()(BasicJsonType& j, T&& val) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
-> decltype(to_json(j, std::forward<T>(val)), void())
{
return to_json(j, std::forward<T>(val));
}
template<typename BasicJsonType, typename T>
void call(BasicJsonType& /*unused*/, T&& /*unused*/, priority_tag<0> /*unused*/) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find to_json() method in T's namespace");
#ifdef _MSC_VER
// MSVC does not show a stacktrace for the above assert
using decayed = uncvref_t<T>;
static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
"forcing MSVC stacktrace to show which T we're talking about.");
#endif
}
public:
template<typename BasicJsonType, typename T>
void operator()(BasicJsonType& j, T&& val) const
noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {})))
{
return call(j, std::forward<T>(val), priority_tag<1> {});
}
};
}

View file

@ -1807,9 +1807,12 @@ void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
external_constructor<value_t::object>::construct(j, std::move(obj));
}
template<typename BasicJsonType, typename T, std::size_t N,
enable_if_t<not std::is_constructible<typename BasicJsonType::string_t, T (&)[N]>::value, int> = 0>
void to_json(BasicJsonType& j, T (&arr)[N])
template <
typename BasicJsonType, typename T, std::size_t N,
enable_if_t<not std::is_constructible<typename BasicJsonType::string_t,
const T (&)[N]>::value,
int> = 0 >
void to_json(BasicJsonType& j, const T (&arr)[N])
{
external_constructor<value_t::array>::construct(j, arr);
}
@ -1842,35 +1845,12 @@ void to_json(BasicJsonType& j, const std::tuple<Args...>& t)
struct to_json_fn
{
private:
template<typename BasicJsonType, typename T>
auto call(BasicJsonType& j, T&& val, priority_tag<1> /*unused*/) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
auto operator()(BasicJsonType& j, T&& val) const noexcept(noexcept(to_json(j, std::forward<T>(val))))
-> decltype(to_json(j, std::forward<T>(val)), void())
{
return to_json(j, std::forward<T>(val));
}
template<typename BasicJsonType, typename T>
void call(BasicJsonType& /*unused*/, T&& /*unused*/, priority_tag<0> /*unused*/) const noexcept
{
static_assert(sizeof(BasicJsonType) == 0,
"could not find to_json() method in T's namespace");
#ifdef _MSC_VER
// MSVC does not show a stacktrace for the above assert
using decayed = uncvref_t<T>;
static_assert(sizeof(typename decayed::force_msvc_stacktrace) == 0,
"forcing MSVC stacktrace to show which T we're talking about.");
#endif
}
public:
template<typename BasicJsonType, typename T>
void operator()(BasicJsonType& j, T&& val) const
noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {})))
{
return call(j, std::forward<T>(val), priority_tag<1> {});
}
};
}
@ -11147,9 +11127,11 @@ struct adl_serializer
@param[in,out] j JSON value to write to
@param[in] val value to read from
*/
template<typename BasicJsonType, typename ValueType>
static void to_json(BasicJsonType& j, ValueType&& val) noexcept(
template <typename BasicJsonType, typename ValueType>
static auto to_json(BasicJsonType& j, ValueType&& val) noexcept(
noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val))))
-> decltype(::nlohmann::to_json(j, std::forward<ValueType>(val)),
void())
{
::nlohmann::to_json(j, std::forward<ValueType>(val));
}