type_name_as_string.hpp

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// SPDX-FileCopyrightText: 2006-2024, Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2024, Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#if defined(__GNUC__) || defined(__clang__)
#    include <cxxabi.h>
#endif // defined(__GNUC__) || defined(__clang__)
 
#include <cstdlib>
#include <functional>
#include <memory>
#include <string>
#include <typeinfo>
 
#include <sharg/platform.hpp>
 
namespace sharg::detail
{
 
template <typename type>
inline std::string const type_name_as_string = []()
{
    std::string demangled_name{};
#if defined(__GNUC__) || defined(__clang__) // clang and gcc only return a mangled name.
    using safe_ptr_t = std::unique_ptr<char, std::function<void(char *)>>;
 
    // https://gcc.gnu.org/onlinedocs/libstdc++/libstdc++-html-USERS-4.3/a01696.html
    int status{};
    safe_ptr_t demangled_name_ptr{abi::__cxa_demangle(typeid(type).name(), 0, 0, &status),
                                  [](char * name_ptr)
                                  {
                                      free(name_ptr);
                                  }};
 
    // We exclude status != 0, because this code can't be reached normally, only if there is a defect in the compiler
    // itself, since the type is directly given by the compiler. See https://github.com/seqan/seqan3/pull/2311.
    // LCOV_EXCL_START
    if (status != 0)
    {
        demangled_name =
            std::string{typeid(type).name()} + " (abi::__cxa_demangle error status (" + std::to_string(status) + "): "
            + (status == -1 ? "A memory allocation failure occurred."
                            : (status == -2 ? "mangled_name is not a valid name under the C++ ABI mangling rules."
                                            : (status == -3 ? "One of the arguments is invalid." : "Unknown Error")))
            + ")";
        return demangled_name;
    }
    // LCOV_EXCL_STOP
 
    demangled_name = std::string{std::addressof(*demangled_name_ptr)};
#else  // e.g. MSVC
    demangled_name = typeid(type).name();
#endif // defined(__GNUC__) || defined(__clang__)
 
    if constexpr (std::is_const_v<std::remove_reference_t<type>>)
        demangled_name += " const";
    if constexpr (std::is_lvalue_reference_v<type>)
        demangled_name += " &";
    if constexpr (std::is_rvalue_reference_v<type>)
        demangled_name += " &&";
 
    return demangled_name;
}();
 
} // namespace sharg::detail