qobjectrefcast.h

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/

#pragma once

#include <concepts>
#include <source_location>
#include <stdexcept>
#include <QObject>
#include "sllconfig.h"

namespace LC::Util
{
    struct BadQObjectCast : std::runtime_error
    {
        using std::runtime_error::runtime_error;
    };

    namespace detail
    {
        [[noreturn, gnu::cold, gnu::noinline]]
        void UTIL_SLL_API NotifyCastError (const QObject *object, const char *target, const std::source_location& loc);
    }
}

namespace LC
{
    template<typename Target, std::derived_from<QObject> Src>
        requires (!std::is_pointer_v<Target>)
    decltype (auto) qobject_ref_cast (Src *obj, std::source_location loc = std::source_location::current ())
    {
        if (const auto result = qobject_cast<Target*> (obj))
            return *result;

        Util::detail::NotifyCastError (obj, typeid (Target).name (), loc);
    }

    template<typename Target, std::derived_from<QObject> Src>
        requires (!std::is_pointer_v<Target>)
    decltype (auto) qobject_ref_cast (Src& obj, std::source_location loc = std::source_location::current ())
    {
        return qobject_ref_cast<Target> (&obj, loc);
    }
}