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#ifndef RFL_PARSING_PARSER_VARIANT_HPP_
#define RFL_PARSING_PARSER_VARIANT_HPP_
#include <map>
#include <optional>
#include <type_traits>
#include <variant>
#include "../NamedTuple.hpp"
#include "../Ref.hpp"
#include "../Result.hpp"
#include "../Variant.hpp"
#include "../always_false.hpp"
#include "../internal/to_ptr_field.hpp"
#include "FieldVariantParser.hpp"
#include "Parent.hpp"
#include "Parser_base.hpp"
#include "VariantAlternativeWrapper.hpp"
#include "schema/Type.hpp"
#include "schemaful/IsSchemafulReader.hpp"
#include "schemaful/IsSchemafulWriter.hpp"
#include "schemaful/VariantReader.hpp"
#include "to_single_error_message.hpp"
namespace rfl::parsing {
template <class R, class W, class... AlternativeTypes, class ProcessorsType>
requires AreReaderAndWriter<R, W, std::variant<AlternativeTypes...>>
class Parser<R, W, std::variant<AlternativeTypes...>, ProcessorsType> {
template <class T>
using ptr_field_t =
decltype(internal::to_ptr_field(std::declval<const T&>()));
using ParentType = Parent<W>;
public:
using InputVarType = typename R::InputVarType;
static Result<std::variant<AlternativeTypes...>> read(
const R& _r, const InputVarType& _var) noexcept {
if constexpr (internal::all_fields<std::tuple<AlternativeTypes...>>()) {
if constexpr (schemaful::IsSchemafulReader<R>) {
using WrappedType = rfl::Variant<NamedTuple<AlternativeTypes>...>;
return Parser<R, W, WrappedType, ProcessorsType>::read(_r, _var)
.transform(
[](auto&& _variant) -> std::variant<AlternativeTypes...> {
return std::move(_variant).visit([](auto&& _named_tuple) {
return std::variant<AlternativeTypes...>(std::move(
std::move(_named_tuple).fields().template get<0>()));
});
});
} else {
const auto wrap = [](auto&& _v) {
return std::variant<AlternativeTypes...>(std::move(_v));
};
const auto to_std_variant = [&](auto&& _v) {
return rfl::visit(wrap, std::move(_v));
};
return FieldVariantParser<R, W, ProcessorsType,
AlternativeTypes...>::read(_r, _var)
.transform(to_std_variant);
}
} else if constexpr (schemaful::IsSchemafulReader<R>) {
using V =
schemaful::VariantReader<R, W, std::variant<AlternativeTypes...>,
ProcessorsType, AlternativeTypes...>;
return _r.to_union(_var).and_then([&](const auto& _u) {
return _r.template read_union<std::variant<AlternativeTypes...>, V>(_u);
});
} else if constexpr (ProcessorsType::add_tags_to_variants_) {
using FieldVariantType =
rfl::Variant<VariantAlternativeWrapper<AlternativeTypes>...>;
const auto from_field_variant =
[](auto&& _field) -> std::variant<AlternativeTypes...> {
return std::move(_field.value());
};
return Parser<R, W, FieldVariantType, ProcessorsType>::read(_r, _var)
.transform([&](FieldVariantType&& _f) {
return _f.visit(from_field_variant);
});
} else {
std::optional<std::variant<AlternativeTypes...>> result;
std::vector<Error> errors;
read_variant(
_r, _var, &result, &errors,
std::make_integer_sequence<int, sizeof...(AlternativeTypes)>());
if (result) {
return std::move(*result);
} else {
return error(
to_single_error_message(errors,
"Could not parse the variant. Each of the "
"possible alternatives failed "
"for the following reasons: ",
100000));
}
}
}
template <class P>
static void write(const W& _w,
const std::variant<AlternativeTypes...>& _variant,
const P& _parent) noexcept {
if constexpr (internal::all_fields<std::tuple<AlternativeTypes...>>()) {
if constexpr (schemaful::IsSchemafulWriter<W>) {
using WrappedType = rfl::Variant<
NamedTuple<Field<AlternativeTypes::name_,
const typename AlternativeTypes::Type*>>...>;
const auto to_wrapped = [](const auto& _variant) -> WrappedType {
return std::visit(
[](const auto& _field) -> WrappedType {
return make_named_tuple(internal::to_ptr_field(_field));
},
_variant);
};
Parser<R, W, WrappedType, ProcessorsType>::write(
_w, to_wrapped(_variant), _parent);
} else {
const auto wrap = [](const auto& _v) {
return rfl::Variant<ptr_field_t<AlternativeTypes>...>(
internal::to_ptr_field(_v));
};
const auto to_rfl_variant = [&](const auto& _v) {
return std::visit(wrap, _v);
};
FieldVariantParser<
R, W, ProcessorsType,
ptr_field_t<AlternativeTypes>...>::write(_w,
to_rfl_variant(_variant),
_parent);
}
} else if constexpr (schemaful::IsSchemafulWriter<W>) {
return std::visit(
[&](const auto& _v) {
using Type = std::remove_cvref_t<decltype(_v)>;
auto u = ParentType::add_union(_w, _parent);
using UnionType = typename ParentType::template Union<decltype(u)>;
auto p = UnionType{.index_ = static_cast<size_t>(_variant.index()),
.union_ = &u};
Parser<R, W, Type, ProcessorsType>::write(_w, _v, p);
},
_variant);
} else if constexpr (ProcessorsType::add_tags_to_variants_) {
using FieldVariantType =
rfl::Variant<VariantAlternativeWrapper<const AlternativeTypes*>...>;
const auto to_field_variant =
[]<class T>(const T& _t) -> FieldVariantType {
return VariantAlternativeWrapper<const T*>(&_t);
};
Parser<R, W, FieldVariantType, ProcessorsType>::write(
_w, std::visit(to_field_variant, _variant), _parent);
} else {
const auto handle = [&](const auto& _v) {
using Type = std::remove_cvref_t<decltype(_v)>;
Parser<R, W, Type, ProcessorsType>::write(_w, _v, _parent);
};
return std::visit(handle, _variant);
}
}
static schema::Type to_schema(
std::map<std::string, schema::Type>* _definitions) {
if constexpr (internal::all_fields<std::tuple<AlternativeTypes...>>()) {
return FieldVariantParser<R, W, ProcessorsType,
AlternativeTypes...>::to_schema(_definitions);
} else if constexpr (ProcessorsType::add_tags_to_variants_) {
using FieldVariantType =
rfl::Variant<VariantAlternativeWrapper<AlternativeTypes>...>;
return Parser<R, W, FieldVariantType, ProcessorsType>::to_schema(
_definitions);
} else {
std::vector<schema::Type> types;
build_schema(
_definitions, &types,
std::make_integer_sequence<int, sizeof...(AlternativeTypes)>());
return schema::Type{schema::Type::AnyOf{.types_ = std::move(types)}};
}
}
private:
template <size_t _i>
static void add_to_schema(std::map<std::string, schema::Type>* _definitions,
std::vector<schema::Type>* _types) noexcept {
using U = std::remove_cvref_t<
std::variant_alternative_t<_i, std::variant<AlternativeTypes...>>>;
_types->push_back(Parser<R, W, U, ProcessorsType>::to_schema(_definitions));
}
template <int... _is>
static void build_schema(std::map<std::string, schema::Type>* _definitions,
std::vector<schema::Type>* _types,
std::integer_sequence<int, _is...>) noexcept {
(add_to_schema<_is>(_definitions, _types), ...);
}
template <int _i>
static void read_one_alternative(
const R& _r, const InputVarType& _var,
std::optional<std::variant<AlternativeTypes...>>* _result,
std::vector<Error>* _errors) noexcept {
if (!*_result) {
using AltType =
std::remove_cvref_t<internal::nth_element_t<_i, AlternativeTypes...>>;
auto res = Parser<R, W, AltType, ProcessorsType>::read(_r, _var);
if (res) {
*_result = std::move(*res);
} else {
_errors->emplace_back(res.error());
}
}
}
template <int... _is>
static void read_variant(
const R& _r, const InputVarType& _var,
std::optional<std::variant<AlternativeTypes...>>* _result,
std::vector<Error>* _errors,
std::integer_sequence<int, _is...>) noexcept {
(read_one_alternative<_is>(_r, _var, _result, _errors), ...);
}
};
} // namespace rfl::parsing
#endif
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