Tuple.hpp

#pragma once
 
#include "data/cassandra/impl/ManagedObject.hpp"
#include "util/UnsupportedType.hpp"
 
#include <cassandra.h>
#include <xrpl/basics/base_uint.h>
 
#include <cstddef>
#include <cstdint>
#include <functional>
#include <stdexcept>
#include <string>
#include <string_view>
#include <tuple>
#include <type_traits>
 
namespace data::cassandra::impl {
 
class Tuple : public ManagedObject<CassTuple> {
    static constexpr auto kDeleter = [](CassTuple* ptr) { cass_tuple_free(ptr); };
 
public:
    /* implicit */ Tuple(CassTuple* ptr);
 
    template <typename... Types>
    explicit Tuple(std::tuple<Types...>&& value)
        : ManagedObject{cass_tuple_new(std::tuple_size<std::tuple<Types...>>{}), kDeleter}
    {
        std::apply(std::bind_front(&Tuple::bind<Types...>, this), std::move(value));
    }
 
    template <typename... Args>
    void
    bind(Args&&... args) const
    {
        std::size_t idx = 0;
        (this->bindAt<Args>(idx++, std::forward<Args>(args)), ...);
    }
 
    template <typename Type>
    void
    bindAt(std::size_t const idx, Type&& value) const
    {
        using std::to_string;
        auto const throwErrorIfNeeded = [idx](CassError rc, std::string_view label) {
            if (rc != CASS_OK) {
                auto const tag = '[' + std::string{label} + ']';
                throw std::logic_error(
                    tag + " at idx " + to_string(idx) + ": " + cass_error_desc(rc)
                );
            }
        };
 
        using DecayedType = std::decay_t<Type>;
 
        if constexpr (std::is_same_v<DecayedType, bool>) {
            auto const rc = cass_tuple_set_bool(*this, idx, value ? cass_true : cass_false);
            throwErrorIfNeeded(rc, "Bind bool");
        }
        // clio only uses bigint (int64_t) so we convert any incoming type
        else if constexpr (std::is_convertible_v<DecayedType, int64_t>) {
            auto const rc = cass_tuple_set_int64(*this, idx, std::forward<Type>(value));
            throwErrorIfNeeded(rc, "Bind int64");
        } else if constexpr (std::is_same_v<DecayedType, xrpl::uint256>) {
            auto const rc = cass_tuple_set_bytes(
                *this,
                idx,
                static_cast<cass_byte_t const*>(static_cast<unsigned char const*>(value.data())),
                value.size()
            );
            throwErrorIfNeeded(rc, "Bind xrpl::uint256");
        } else {
            // type not supported for binding
            static_assert(util::Unsupported<DecayedType>);
        }
    }
};
 
class TupleIterator : public ManagedObject<CassIterator> {
public:
    /* implicit */ TupleIterator(CassIterator* ptr);
 
    [[nodiscard]] static TupleIterator
    fromTuple(CassValue const* value);
 
    template <typename... Types>
    [[nodiscard]] std::tuple<Types...>
    extract() const
    {
        return {extractNext<Types>()...};
    }
 
private:
    template <typename Type>
    [[nodiscard]] Type
    extractNext() const
    {
        using std::to_string;
        Type output;
 
        if (not cass_iterator_next(*this))
            throw std::logic_error("Could not extract next value from tuple iterator");
 
        auto const throwErrorIfNeeded = [](CassError rc, std::string_view label) {
            if (rc != CASS_OK) {
                auto const tag = '[' + std::string{label} + ']';
                throw std::logic_error(tag + ": " + cass_error_desc(rc));
            }
        };
 
        using DecayedType = std::decay_t<Type>;
 
        // clio only uses bigint (int64_t) so we convert any incoming type
        if constexpr (std::is_convertible_v<DecayedType, int64_t>) {
            int64_t out = 0;
            auto const rc = cass_value_get_int64(cass_iterator_get_value(*this), &out);
            throwErrorIfNeeded(rc, "Extract int64 from tuple");
            output = static_cast<DecayedType>(out);
        } else {
            // type not supported for extraction
            static_assert(util::Unsupported<DecayedType>);
        }
 
        return output;
    }
};
 
}  // namespace data::cassandra::impl