Root.hh

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#ifndef __NCPP_ROOT_HH
#define __NCPP_ROOT_HH
 
#include <type_traits>
#include <string>
#include <notcurses/notcurses.h>
 
#include "_helpers.hh"
#include "_exceptions.hh"
 
namespace ncpp {
#if defined (NCPP_EXCEPTIONS_PLEASE)
#define NOEXCEPT_MAYBE
#else
#define NOEXCEPT_MAYBE noexcept
#endif
 
    class NotCurses;
 
    class NCPP_API_EXPORT Root
    {
    protected:
        static constexpr char ncpp_invalid_state_message[] = "notcurses++ is in an invalid state (already stopped?)";
 
    public:
        notcurses* get_notcurses () const;
 
        NotCurses* get_notcurses_cpp () const
        {
            return nc;
        }
 
    protected:
        explicit Root (NotCurses *ncinst)
            : nc (ncinst)
        {}
 
        template<typename TRet = bool, typename TValue = int>
        static TRet error_guard (TValue ret, TValue error_value)
        {
            static constexpr bool ret_is_bool = std::is_same_v<TRet, bool>;
 
            if constexpr (!ret_is_bool) {
                static_assert (std::is_same_v<TRet, TValue>, "Both TRet and TValue must be the same type unless TValue is 'bool'");
            }
 
            if (ret != error_value) {
                if constexpr (ret_is_bool) {
                    return true;
                } else {
                    return ret;
                }
            }
 
#if defined (NCPP_EXCEPTIONS_PLEASE)
            throw call_error ("Call returned an error value");
#else
            if constexpr (ret_is_bool) {
                return false;
            } else {
                return ret;
            }
#endif
        }
 
        template<typename TRet = bool, typename TValue = int>
        static TRet error_guard_cond ([[maybe_unused]] TValue ret, bool error_value)
        {
            static constexpr bool ret_is_bool = std::is_same_v<TRet, bool>;
 
            if constexpr (!ret_is_bool) {
                static_assert (std::is_same_v<TRet, TValue>, "Both TRet and TValue must be the same type unless TValue is 'bool'");
            }
 
            if (!error_value) {
                if constexpr (ret_is_bool) {
                    return true;
                } else {
                    return ret;
                }
            }
 
#if defined (NCPP_EXCEPTIONS_PLEASE)
            throw call_error ("Call returned an error value");
#else
            if constexpr (ret_is_bool) {
                return false;
            } else {
                return ret;
            }
#endif
        }
 
        // All the objects which need to destroy notcurses entities (planes, panelreel etc etc) **have to** call this
        // function before calling to notcurses from their destructor. This is to prevent a segfault when
        // NotCurses::stop has been called and the app uses smart pointers holding NotCurses objects which may be
        // destructed **after** notcurses is stopped.
        bool is_notcurses_stopped () const noexcept;
 
    private:
        NotCurses *nc = nullptr;
    };
}
#endif