bwidgets/inc/basic_widgets/core/error_helper.hpp

#ifndef BWIDGETS_ERROR_HELPER_HPP
#define BWIDGETS_ERROR_HELPER_HPP

#include <functional>

#include <basic_widgets/core/type/sdl_error.hpp>

extern "C" {
    auto SDL_GetError() -> const char*;
}

namespace bwidgets
{
    // Throw a E exception with message w if ptr is null. Otherwise return ptr.
    template<Exception E, typename T>
    inline auto ptr_or_throw(T* const ptr, const std::string_view w = "unknown") -> T*
    {
        std::string what;
        if constexpr (std::is_same_v<E, SDLError>)
            what = w == "unknown" ? SDL_GetError() : w;
        else what = w;

        if (ptr == nullptr) throw E(what);
        return ptr;
    }

    // Check a return code with the success function passed. If success return false
    // throw an E Exception with message w.
    template<Exception E, typename T>
    inline auto success_or_throw(
      const T code, const std::string_view w = "unknown",
      const std::function<bool(T)>& success = [](T code) { return code == 0; }) -> T
    {
        // If exception type is SDLError and no value or unknown was passed for w, get
        // the last error message using SDL facilities.
        if constexpr (std::is_same_v<E, SDLError>) {
            const std::string what {w == "unknown" ? SDL_GetError() : w};
            if (code < 0) throw E(what);
        }
        else if (!success(code)) throw E(w.data());

        return code;
    }
}

#endif