iterator.hpp

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/*
    Copyright (C) 2011 - 2022
    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.
*/

/**
 * @file
 * Contains the base iterator class for the gui2 widgets.
 *
 * See @ref gui2_iterator for more information.
 */

#pragma once

#include "gui/auxiliary/iterator/policy_order.hpp"

namespace gui2::iteration
{

/**
 * The iterator class.
 *
 * See @ref gui2_iterator_iterator for more information.
 */
template <class order>
class iterator : private order
{
public:
    iterator(const iterator&) = delete;
    iterator& operator=(const iterator&) = delete;

    /**
     * Constructor.
     *
     * @param root                The widget where to start the iteration.
     */
    iterator(widget& root) : order(root)
    {
    }

    /**
     * Has the iterator reached the end?
     *
     * @returns                   The status.
     * @retval [true]             At the end.
     * @retval [false]            Not at the end.
     */
    bool at_end() const
    {
        return order::at_end();
    }

    /**
     * Visit the next widget.
     *
     * @pre                       The following assertion holds:
     *                            @code at_end() == false @endcode
     *
     * @throws                    A @ref range_error exception upon pre
     *                            condition violation.
     *
     * @returns                   Whether the next widget can be safely
     *                            deferred.
     */
    bool next()
    {
        return order::next();
    }

    /** See @ref next. */
    iterator<order>& operator++()
    {
        order::next();
        return *this;
    }

    /**
     * Returns the current widget.
     *
     * @returns                   The current widget.
     */
    widget& operator*()
    {
        return order::operator*();
    }

    /** See @ref operator*. */
    widget* operator->()
    {
        return &(operator*());
    }

    /** See @ref operator*. */
    widget* get()
    {
        return operator->();
    }
};

/* Helper aliases templates. */

template<bool visit_self, bool visit_internal, bool visit_child>
using top_down_iterator = iterator<policy::order::top_down<visit_self, visit_internal, visit_child>>;

template<bool visit_self, bool visit_internal, bool visit_child>
using bottom_up_iterator = iterator<policy::order::bottom_up<visit_self, visit_internal, visit_child>>;

} // namespace gui2::iteration