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#ifndef RFL_BSON_READER_HPP_
#define RFL_BSON_READER_HPP_
#include <bson/bson.h>
#include <array>
#include <concepts>
#include <cstddef>
#include <exception>
#include <map>
#include <memory>
#include <optional>
#include <sstream>
#include <stdexcept>
#include <string>
#include <string_view>
#include <type_traits>
#include <unordered_map>
#include <vector>
#include "../Box.hpp"
#include "../Bytestring.hpp"
#include "../Result.hpp"
#include "../always_false.hpp"
#include "../internal/ptr_cast.hpp"
namespace rfl {
namespace bson {
/// Please refer to https://mongoc.org/libbson/current/api.html
struct Reader {
struct BSONInputArray {
const bson_value_t* val_;
};
struct BSONInputObject {
const bson_value_t* val_;
};
struct BSONInputVar {
const bson_value_t* val_;
};
using InputArrayType = BSONInputArray;
using InputObjectType = BSONInputObject;
using InputVarType = BSONInputVar;
template <class T>
static constexpr bool has_custom_constructor =
(requires(InputVarType var) { T::from_bson_obj(var); });
rfl::Result<InputVarType> get_field_from_array(
const size_t _idx, const InputArrayType& _arr) const noexcept {
bson_t b;
bson_iter_t iter;
const auto doc = _arr.val_->value.v_doc;
if (bson_init_static(&b, doc.data, doc.data_len)) {
if (bson_iter_init(&iter, &b)) {
size_t i = 0;
while (bson_iter_next(&iter)) {
if (i == _idx) {
return to_input_var(&iter);
}
++i;
}
} else {
return error("Could not init the array iteration.");
}
} else {
return error("Could not init array.");
}
return error("Index " + std::to_string(_idx) + " of of bounds.");
}
rfl::Result<InputVarType> get_field_from_object(
const std::string& _name, const InputObjectType& _obj) const noexcept {
bson_t b;
bson_iter_t iter;
const auto doc = _obj.val_->value.v_doc;
if (bson_init_static(&b, doc.data, doc.data_len)) {
if (bson_iter_init(&iter, &b)) {
while (bson_iter_next(&iter)) {
auto key = std::string(bson_iter_key(&iter));
if (key == _name) {
return to_input_var(&iter);
}
}
}
}
return error("No field named '" + _name + "' was found.");
}
bool is_empty(const InputVarType& _var) const noexcept {
return _var.val_->value_type == BSON_TYPE_NULL;
}
template <class T>
rfl::Result<T> to_basic_type(const InputVarType& _var) const noexcept {
const auto btype = _var.val_->value_type;
const auto value = _var.val_->value;
if constexpr (std::is_same<std::remove_cvref_t<T>, std::string>()) {
switch (btype) {
case BSON_TYPE_UTF8:
return std::string(value.v_utf8.str, value.v_utf8.len);
case BSON_TYPE_SYMBOL:
return std::string(value.v_symbol.symbol, value.v_symbol.len);
default:
return error(
"Could not cast to string. The type must be UTF8 or symbol.");
}
} else if constexpr (std::is_same<std::remove_cvref_t<T>,
rfl::Bytestring>()) {
if (btype != BSON_TYPE_BINARY) {
return error("Could not cast to bytestring.");
}
if (value.v_binary.subtype != BSON_SUBTYPE_BINARY) {
return error(
"The BSON subtype must be a binary in order to read into a "
"bytestring.");
}
const auto data =
internal::ptr_cast<const std::byte*>(value.v_binary.data);
return rfl::Bytestring(data, data + value.v_binary.data_len);
} else if constexpr (std::is_same<std::remove_cvref_t<T>, bool>()) {
if (btype != BSON_TYPE_BOOL) {
return error("Could not cast to boolean.");
}
return value.v_bool;
} else if constexpr (std::is_floating_point<std::remove_cvref_t<T>>()) {
if (btype != BSON_TYPE_DOUBLE) {
return error(
"Could not cast to numeric value. The type must be double, "
"int32, int64 or date_time.");
}
return static_cast<T>(value.v_double);
} else if constexpr (std::is_integral<std::remove_cvref_t<T>>()) {
switch (btype) {
case BSON_TYPE_INT32:
return static_cast<T>(value.v_int32);
case BSON_TYPE_INT64:
return static_cast<T>(value.v_int64);
case BSON_TYPE_DATE_TIME:
return static_cast<T>(value.v_datetime);
default:
return error(
"Could not cast to numeric value. The type must be "
"int32, int64 or date_time.");
}
} else if constexpr (std::is_same<std::remove_cvref_t<T>, bson_oid_t>()) {
if (btype != BSON_TYPE_OID) {
return error("Could not cast to OID.");
}
return value.v_oid;
} else {
static_assert(rfl::always_false_v<T>, "Unsupported type.");
}
}
rfl::Result<InputArrayType> to_array(
const InputVarType& _var) const noexcept {
const auto btype = _var.val_->value_type;
if (btype != BSON_TYPE_ARRAY && btype != BSON_TYPE_DOCUMENT) {
return error("Could not cast to an array.");
}
return InputArrayType{_var.val_};
}
template <class ArrayReader>
std::optional<Error> read_array(const ArrayReader& _array_reader,
const InputArrayType& _arr) const noexcept {
bson_t b;
bson_iter_t iter;
const auto doc = _arr.val_->value.v_doc;
if (bson_init_static(&b, doc.data, doc.data_len)) {
if (bson_iter_init(&iter, &b)) {
while (bson_iter_next(&iter)) {
const auto err = _array_reader.read(to_input_var(&iter));
if (err) {
return err;
}
}
} else {
return Error("Could not init the array iteration.");
}
} else {
return Error("Could not init array.");
}
return std::nullopt;
}
template <class ObjectReader>
std::optional<Error> read_object(const ObjectReader& _object_reader,
const InputObjectType& _obj) const noexcept {
bson_t b;
bson_iter_t iter;
const auto doc = _obj.val_->value.v_doc;
if (bson_init_static(&b, doc.data, doc.data_len)) {
if (bson_iter_init(&iter, &b)) {
while (bson_iter_next(&iter)) {
const char* k = bson_iter_key(&iter);
_object_reader.read(std::string_view(k), to_input_var(&iter));
}
} else {
return Error("Could not init the object iteration.");
}
} else {
return Error("Could not init object.");
}
return std::nullopt;
}
rfl::Result<InputObjectType> to_object(
const InputVarType& _var) const noexcept {
const auto btype = _var.val_->value_type;
if (btype != BSON_TYPE_DOCUMENT) {
return error("Could not cast to a document.");
}
return InputObjectType{_var.val_};
}
template <class T>
rfl::Result<T> use_custom_constructor(
const InputVarType& _var) const noexcept {
try {
return T::from_bson_obj(_var);
} catch (std::exception& e) {
return error(e.what());
}
}
private:
InputVarType to_input_var(bson_iter_t* _iter) const noexcept {
return InputVarType{bson_iter_value(_iter)};
}
};
} // namespace bson
} // namespace rfl
#endif
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