scrollbar_container_private.hpp

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/*
   Copyright (C) 2009 - 2016 by Mark de Wever <[email protected]>
   Part of the Battle for Wesnoth Project http://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

#ifndef GUI_WIDGETS_SCROLLBAR_CONTAINER_PRIVATE_HPP_INCLUDED
#define GUI_WIDGETS_SCROLLBAR_CONTAINER_PRIVATE_HPP_INCLUDED

#include "gui/widgets/scrollbar_container.hpp"

#include "utils/const_clone.hpp"

/**
 * @file
 * Helper for header for the scrollbar_container.
 *
 * @note This file should only be included by scrollbar_container.cpp.
 *
 * This file is being used for a small experiment in which some private
 * functions of tscrollbar_container are no longer in tscrollbar_container
 * but moved in a friend class with static functions. The goal is to have
 * less header recompilations, when there's a need to add or remove a private
 * function.  Also non-trivial functions like 'const foo& bar() const' and
 * 'foo& bar()' are wrapped in a template to avoid code duplication (for
 * typing not for the binary) to make maintenance easier.
 */

namespace gui2
{

/**
 * Helper to implement private functions without modifying the header.
 *
 * The class is a helper to avoid recompilation and only has static
 * functions.
 */
struct tscrollbar_container_implementation
{
    /**
     * Implementation for the wrappers for
     * [const] twidget* tscrollbar_container::find_at(
     * const tpoint&, const bool) [const].
     *
     * @tparam W                  twidget or const twidget.
     */
    template <class W>
    static W*
    find_at(typename utils::tconst_clone<tscrollbar_container, W>::reference
                    scrollbar_container,
            const tpoint& coordinate,
            const bool must_be_active)
    {

        assert(scrollbar_container.content_
               && scrollbar_container.content_grid_);

        W* result = scrollbar_container.tcontainer_::find_at(coordinate,
                                                             must_be_active);

        if(result == scrollbar_container.content_) {
            return scrollbar_container.content_grid_->find_at(coordinate,
                                                              must_be_active);
        }

        return result;
    }

    /**
     * Implementation for the wrappers for
     * [const] twidget* tscrollbar_container::find(
     * const std::string&, const bool) [const].
     *
     * @tparam W                  twidget or const twidget.
     */
    template <class W>
    static W*
    find(typename utils::tconst_clone<tscrollbar_container, W>::reference
                 scrollbar_container,
         const std::string& id,
         const bool must_be_active)
    {
        // Inherited.
        W* result = scrollbar_container.tcontainer_::find(id, must_be_active);

        // Can be called before finalize so test instead of assert for the grid.
        if(!result && scrollbar_container.content_grid_) {
            result = scrollbar_container.content_grid_->find(id,
                                                             must_be_active);
        }

        return result;
    }
};

} // namespace gui2

#endif