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#ifndef RFL_AVRO_READER_HPP_
#define RFL_AVRO_READER_HPP_
#include <avro.h>
#include <cstddef>
#include <exception>
#include <string>
#include <string_view>
#include <type_traits>
#include <vector>
#include "../Bytestring.hpp"
#include "../Result.hpp"
#include "../always_false.hpp"
#include "../internal/is_literal.hpp"
#include "../parsing/schemaful/IsSchemafulReader.hpp"
namespace rfl::avro {
struct Reader {
struct AVROInputArray {
const avro_value_t* val_;
};
struct AVROInputObject {
const avro_value_t* val_;
};
struct AVROInputMap {
const avro_value_t* val_;
};
struct AVROInputUnion {
const avro_value_t* val_;
};
struct AVROInputVar {
const avro_value_t* val_;
};
using InputArrayType = AVROInputArray;
using InputObjectType = AVROInputObject;
using InputMapType = AVROInputMap;
using InputUnionType = AVROInputUnion;
using InputVarType = AVROInputVar;
template <class T>
static constexpr bool has_custom_constructor =
(requires(InputVarType var) { T::from_avro_obj(var); });
bool is_empty(const InputVarType& _var) const noexcept {
return avro_value_get_type(_var.val_) == AVRO_NULL;
}
template <class T>
rfl::Result<T> to_basic_type(const InputVarType& _var) const noexcept {
const auto type = avro_value_get_type(_var.val_);
if constexpr (std::is_same<std::remove_cvref_t<T>, std::string>()) {
const char* c_str = nullptr;
size_t size = 0;
const auto err = avro_value_get_string(_var.val_, &c_str, &size);
if (err) {
return error("Could not cast to string.");
}
if (size == 0) {
return std::string("");
}
return std::string(c_str, size - 1);
} else if constexpr (std::is_same<std::remove_cvref_t<T>,
rfl::Bytestring>()) {
const void* ptr = nullptr;
size_t size = 0;
const auto err = avro_value_get_bytes(_var.val_, &ptr, &size);
if (err) {
return error("Could not cast to bytestring.");
}
const auto data = internal::ptr_cast<const std::byte*>(ptr);
return rfl::Bytestring(data, data + size - 1);
} else if constexpr (std::is_same<std::remove_cvref_t<T>, bool>()) {
if (type != AVRO_BOOLEAN) {
return rfl::error("Could not cast to boolean.");
}
int result = 0;
avro_value_get_boolean(_var.val_, &result);
return (result != 0);
} else if constexpr (std::is_floating_point<std::remove_cvref_t<T>>()) {
if (type == AVRO_DOUBLE) {
double result = 0.0;
const auto err = avro_value_get_double(_var.val_, &result);
if (err) {
return error("Could not cast to double.");
}
return static_cast<T>(result);
} else if (type == AVRO_FLOAT) {
float result = 0.0;
const auto err = avro_value_get_float(_var.val_, &result);
if (err) {
return error("Could not cast to float.");
}
return static_cast<T>(result);
} else {
return rfl::error(
"Could not cast to numeric value. The type must be float "
"or double.");
}
} else if constexpr (std::is_integral<std::remove_cvref_t<T>>()) {
if (type == AVRO_INT32) {
int32_t result = 0;
const auto err = avro_value_get_int(_var.val_, &result);
if (err) {
return error("Could not cast to int32.");
}
return static_cast<T>(result);
} else if (type == AVRO_INT64) {
int64_t result = 0;
const auto err = avro_value_get_long(_var.val_, &result);
if (err) {
return error("Could not cast to int64.");
}
return static_cast<T>(result);
} else {
return rfl::error(
"Could not cast to numeric value. The type must be integral.");
}
} else if constexpr (internal::is_literal_v<T>) {
int value = 0;
const auto err = avro_value_get_enum(_var.val_, &value);
if (err) {
return error("Could not cast to enum.");
}
return std::remove_cvref_t<T>::from_value(
static_cast<typename std::remove_cvref_t<T>::ValueType>(value));
} else {
static_assert(rfl::always_false_v<T>, "Unsupported type.");
}
}
rfl::Result<InputArrayType> to_array(
const InputVarType& _var) const noexcept {
if (avro_value_get_type(_var.val_) != AVRO_ARRAY) {
return error("Could not cast to an array.");
}
return InputArrayType{_var.val_};
}
rfl::Result<InputObjectType> to_object(
const InputVarType& _var) const noexcept {
const auto type = avro_value_get_type(_var.val_);
if (type != AVRO_RECORD) {
return error("Could not cast to an object.");
}
return InputObjectType{_var.val_};
}
rfl::Result<InputMapType> to_map(const InputVarType& _var) const noexcept {
const auto type = avro_value_get_type(_var.val_);
if (type != AVRO_MAP) {
return error("Could not cast to a map.");
}
return InputMapType{_var.val_};
}
rfl::Result<InputUnionType> to_union(
const InputVarType& _var) const noexcept {
const auto type = avro_value_get_type(_var.val_);
if (type != AVRO_UNION) {
return error("Could not cast to a union.");
}
return InputUnionType{_var.val_};
}
template <class ArrayReader>
std::optional<Error> read_array(const ArrayReader& _array_reader,
const InputArrayType& _arr) const noexcept {
size_t size = 0;
avro_value_get_size(_arr.val_, &size);
for (size_t ix = 0; ix < size; ++ix) {
avro_value_t element;
avro_value_get_by_index(_arr.val_, ix, &element, nullptr);
const auto err = _array_reader.read(InputVarType{&element});
if (err) {
return err;
}
}
return std::nullopt;
}
template <class MapReader>
std::optional<Error> read_map(const MapReader& _map_reader,
const InputMapType& _map) const noexcept {
size_t size = 0;
avro_value_get_size(_map.val_, &size);
for (size_t ix = 0; ix < size; ++ix) {
avro_value_t element;
const char* key = nullptr;
avro_value_get_by_index(_map.val_, ix, &element, &key);
_map_reader.read(std::string_view(key), InputVarType{&element});
}
return std::nullopt;
}
template <class ObjectReader>
std::optional<Error> read_object(const ObjectReader& _object_reader,
const InputObjectType& _obj) const noexcept {
size_t size = 0;
avro_value_get_size(_obj.val_, &size);
for (size_t ix = 0; ix < size; ++ix) {
avro_value_t element;
avro_value_get_by_index(_obj.val_, ix, &element, nullptr);
_object_reader.read(static_cast<int>(ix), InputVarType{&element});
}
return std::nullopt;
}
template <class VariantType, class UnionReaderType>
rfl::Result<VariantType> read_union(
const InputUnionType& _union) const noexcept {
int disc = 0;
auto err = avro_value_get_discriminant(_union.val_, &disc);
if (err) {
return error("Could not get the discriminant.");
}
avro_value_t value;
err = avro_value_get_current_branch(_union.val_, &value);
if (err) {
return error("Could not cast the union type.");
}
return UnionReaderType::read(*this, static_cast<size_t>(disc),
InputVarType{&value});
}
template <class T>
rfl::Result<T> use_custom_constructor(
const InputVarType& _var) const noexcept {
try {
return T::from_avro_obj(_var);
} catch (std::exception& e) {
return rfl::error(e.what());
}
}
};
static_assert(parsing::schemaful::IsSchemafulReader<Reader>,
"This must be a schemaful reader.");
} // namespace rfl::avro
#endif
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