forward_like.h

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#ifndef MYSQL_UTILS_FORWARD_LIKE_H
#define MYSQL_UTILS_FORWARD_LIKE_H
 
/// @file
/// Experimental API header
 
#include <type_traits>  // is_lvalue_reference
#include <utility>      // move
 
/// @addtogroup GroupLibsMysqlUtils
/// @{
 
namespace mysql::utils {
 
/// Implementation of C++23's `std::forward_like`.
//
// Todo: When we have C++23, remove this and use `std::forward_like`.
//
// clang-tidy has many complaints here. Basically the reason is that we are not
// following typical idioms, and the reason for that is that we are implementing
// the idiom. This implementation is equivalent to the "possible implementation"
// at https://en.cppreference.com/w/cpp/utility/forward_like.html
template <class Qualifiers_from_t, class Value_t>
// NOLINTNEXTLINE(cppcoreguidelines-missing-std-forward)
constexpr auto &&forward_like(Value_t &&x) noexcept {
  constexpr bool is_const =
      std::is_const_v<std::remove_reference_t<Qualifiers_from_t>>;
  if constexpr (std::is_lvalue_reference_v<Qualifiers_from_t &&>) {
    if constexpr (is_const)
      return std::as_const(x);
    else
      // NOLINTNEXTLINE(readability-redundant-casting)
      return static_cast<Value_t &>(x);
  } else {
    if constexpr (is_const)
      return std::move(std::as_const(x));
    else
      // NOLINTNEXTLINE(bugprone-move-forwarding-reference)
      return std::move(x);
  }
}
 
}  // namespace mysql::utils
 
// addtogroup GroupLibsMysqlUtils
/// @}
 
#endif  // ifndef MYSQL_UTILS_FORWARD_LIKE_H