result_description_decl.h

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#ifndef A_UTIL_UTIL_RESULT_DETAIL_DESCRIPTION_DECL_HEADER_INCLUDED
#define A_UTIL_UTIL_RESULT_DETAIL_DESCRIPTION_DECL_HEADER_INCLUDED
 
#include <a_util/result/detail/reference_counted_object_intf.h>
#include <a_util/result/result_info_decl.h>
 
#include <cstdint>
 
namespace a_util {
namespace result {
namespace detail {
template <typename DescriptionIntf /*e.g. a_util::result::detail::IErrorDescription*/>
struct ResultDescriptionTraits final {
    typedef ReferenceCountedObjectInterface<DescriptionIntf> ReferenceCountedDescriptionType;
    static const std::uint64_t error_code_bit = 1ull << 63;
    static const std::uint64_t error_code_bitmask = ~error_code_bit;
    static const std::uint64_t error_code_serialize_bitmask = 0x00000000FFFFFFFF;
    static const std::uint64_t error_code_deserialize_bitmask = 0xFFFFFFFF00000000;

    ResultDescriptionTraits() = delete;
    ResultDescriptionTraits(const ResultDescriptionTraits&) = delete;
    ResultDescriptionTraits& operator=(const ResultDescriptionTraits&) = delete;
    ResultDescriptionTraits(ResultDescriptionTraits&&) = delete;
    ResultDescriptionTraits& operator=(ResultDescriptionTraits&&) = delete;

    static bool isDetailedDescriptionSet(std::uint64_t value);

    static bool isErrorCodeSet(std::uint64_t value);

    constexpr static std::uint64_t toInternalErrorCode(std::int32_t error_code) noexcept;

    constexpr static std::int32_t toExternalErrorCode(std::uint64_t error_code) noexcept;

    constexpr static const ReferenceCountedDescriptionType* toInternalErrorPointer(
        std::uint64_t error_code) noexcept;
 
private:
    ~ResultDescriptionTraits();
}; // struct ResultDescriptionTraits


template <typename DescriptionIntf /*e.g. a_util::result::detail::IErrorDescription*/>
class ResultDescription {
    typedef ResultDescriptionTraits<DescriptionIntf> TraitsType; 
 
public:
    typedef ResultDescription<DescriptionIntf> SelfType; 
 
public:
    ResultDescription();
    ResultDescription(const ResultDescription& other);
    ResultDescription& operator=(const ResultDescription& other);
    ResultDescription(ResultDescription&& other);
    ResultDescription& operator=(ResultDescription&& other);

    ~ResultDescription();

    template <typename DescriptionImpl, typename... Args>
    static SelfType makeResultDescription(std::int32_t error_code, Args&&... args);

    template <typename T>
    static SelfType makeResultDescription(
        const ::a_util::result::ResultInfo<T>& result_info) noexcept;

    static SelfType makeResultDescription(std::int32_t error_code);

    DescriptionIntf const* getDetailedDescription() const;

    std::int32_t getErrorCode() const;
 
private:
    // On all systems, a 64Bit variable for storage
    // the most significant bits are used for user flags
    // size of pointer part is system dependent, lower bits
    std::uint64_t _pointer_to_result_or_error_code;

    constexpr ResultDescription(std::int32_t error_code) noexcept;

    constexpr ResultDescription(
        const ReferenceCountedObjectInterface<DescriptionIntf>& error_object) noexcept;
}; // struct ResultDescription

template <typename T>
bool operator==(const ResultDescription<T>& lhs, const ResultDescription<T>& rhs);

template <typename T>
bool operator!=(const ResultDescription<T>& lhs, const ResultDescription<T>& rhs);
 
} // namespace detail
} // namespace result
} // namespace a_util

#include <a_util/result/detail/result_description_impl.h>
 
#endif // A_UTIL_UTIL_RESULT_DETAIL_DESCRIPTION_DECL_HEADER_INCLUDED