scrollbar_container_private.hpp

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/*
    Copyright (C) 2009 - 2024
    by Mark de Wever <koraq@xs4all.nl>
    Part of the Battle for Wesnoth Project https://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.
*/
 
#pragma once
 
#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 scrollbar_container are no longer in scrollbar_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 scrollbar_container_implementation
{
    /**
     * Implementation for the wrappers for
     * [const] widget* scrollbar_container::find_at(
     * const point&, const bool) [const].
     *
     * @tparam W                  widget or const widget.
     */
    template <class W>
    static W*
    find_at(utils::const_clone_ref<scrollbar_container, W>
                    scrollbar_container,
            const point& coordinate,
            const bool must_be_active)
    {
 
        assert(scrollbar_container.content_
               && scrollbar_container.content_grid_);
 
        W* result = scrollbar_container.container_base::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] widget* scrollbar_container::find(
     * const std::string&, const bool) [const].
     *
     * @tparam W                  widget or const widget.
     */
    template <class W>
    static W*
    find(utils::const_clone_ref<scrollbar_container, W>
                 scrollbar_container,
         const std::string& id,
         const bool must_be_active)
    {
        // Inherited.
        W* result = scrollbar_container.container_base::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