abaddon-ppc/discord/json.hpp
2020-11-19 19:18:59 -05:00

149 lines
4.5 KiB
C++

#pragma once
#include <nlohmann/json.hpp>
#include <optional>
#include "../util.hpp"
namespace detail { // more or less because idk what to name this stuff
template<typename T>
inline void json_direct(const ::nlohmann::json &j, const char *key, T &val) {
if constexpr (::util::is_optional<T>::value)
val = j.at(key).get<typename T::value_type>();
else
j.at(key).get_to(val);
}
template<typename T>
inline void json_optional(const ::nlohmann::json &j, const char *key, T &val) {
if constexpr (::util::is_optional<T>::value) {
if (j.contains(key))
val = j.at(key).get<typename T::value_type>();
else
val = ::std::nullopt;
} else {
if (j.contains(key))
j.at(key).get_to(val);
}
}
template<typename T>
inline void json_nullable(const ::nlohmann::json &j, const char *key, T &val) {
if constexpr (::util::is_optional<T>::value) {
const auto &at = j.at(key);
if (!at.is_null())
val = at.get<typename T::value_type>();
else
val = ::std::nullopt;
} else {
const auto &at = j.at(key);
if (!at.is_null())
at.get_to(val);
}
}
template<typename T>
inline void json_optional_nullable(const ::nlohmann::json &j, const char *key, T &val) {
if constexpr (::util::is_optional<T>::value) {
if (j.contains(key)) {
const auto &at = j.at(key);
if (!at.is_null())
val = at.get<typename T::value_type>();
else
val = ::std::nullopt;
} else {
val = ::std::nullopt;
}
} else {
if (j.contains(key)) {
const auto &at = j.at(key);
if (!at.is_null())
at.get_to(val);
}
}
}
template<typename T>
inline void json_update_optional_nullable(const ::nlohmann::json &j, const char *key, T &val) {
if constexpr (::util::is_optional<T>::value) {
if (j.contains(key)) {
const auto &at = j.at(key);
if (!at.is_null())
val = at.get<typename T::value_type>();
else
val = ::std::nullopt;
}
} else {
if (j.contains(key)) {
const auto &at = j.at(key);
if (!at.is_null())
at.get_to(val);
else
val = T();
}
}
}
template<typename T, typename U>
inline void json_update_optional_nullable_default(const ::nlohmann::json &j, const char *key, T &val, const U &fallback) {
if constexpr (::util::is_optional<T>::value) {
if (j.contains(key)) {
const auto &at = j.at(key);
if (at.is_null())
val = fallback;
else
val = at.get<typename T::value_type>();
}
} else {
if (j.contains(key)) {
const auto &at = j.at(key);
if (at.is_null())
val = fallback;
else
at.get_to(val);
}
}
}
} // namespace detail
// get a json value that is guaranteed to be present and non-null
#define JS_D(k, t) \
do { \
detail::json_direct(j, k, t); \
} while (0)
// get a json value that may not be present
#define JS_O(k, t) \
do { \
detail::json_optional(j, k, t); \
} while (0)
// get a json value that may be null
#define JS_N(k, t) \
do { \
detail::json_nullable(j, k, t); \
} while (0)
// get a json value that may not be present or may be null
#define JS_ON(k, t) \
do { \
detail::json_optional_nullable(j, k, t); \
} while (0)
// set from a json value only if it is present. null will assign default-constructed value
#define JS_RD(k, t) \
do { \
detail::json_update_optional_nullable(j, k, t); \
} while (0)
// set from a json value only if it is present. null will assign the given default
#define JS_RV(k, t, d) \
do { \
detail::json_update_optional_nullable_default(j, k, t, d); \
} while (0)
// set a json value from a std::optional only if it has a value
#define JS_IF(k, v) \
do { \
if (v.has_value()) \
j[k] = *v; \
} while (0)