xml_nodes.h

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/*  Copyright (c) SILVERCODERS Ltd, http://silvercoders.com                                                                                  */
/*  Project homepage: https://github.com/docwire/docwire                                                                                     */
/*                                                                                                                                           */
/*  SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-DocWire-Commercial                                                                  */
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#ifndef DOCWIRE_XML_NODES_VIEW_H
#define DOCWIRE_XML_NODES_VIEW_H
 
#include <optional>
#include "checked.h"
#include <ranges>
#include "sentinel.h"
#include "xml_node_ref.h"
#include "xml_iterator_state.h"
#include "xml_reader.h"
 
namespace docwire::xml
{
 
template<safety_policy safety_level = default_safety_level>
class nodes_view : public std::ranges::view_base
{
public:
    class iterator;
    iterator begin() const { return iterator{m_state}; }
    sentinel end() const { return {}; }
 
    explicit nodes_view(not_null<std::shared_ptr<iterator_state<safety_level>>, safety_level> state)
        : m_state(std::move(state)) {}
private:
    not_null<std::shared_ptr<iterator_state<safety_level>>, safety_level> m_state;
};
 
template<safety_policy safety_level>
class nodes_view<safety_level>::iterator
{
    friend class nodes_view<safety_level>;
 
public:
    using iterator_concept  = std::input_iterator_tag;
    using difference_type   = std::ptrdiff_t;
    using value_type        = node_ref<safety_level>;
    using pointer           = const value_type*;
    using reference         = const value_type&;
 
    bool operator==(const sentinel& s) const { return !m_node.has_value(); }
    reference operator*() const { return *m_node; }
    pointer operator->() const { return &*m_node; }
    iterator& operator++()
    {
        if (!m_state->xml_reader.read_next())
        {
            m_node.reset();
            return *this;
        }
        m_node.emplace(m_state);
        return *this;
    }
    void operator++(int)
    {
        ++(*this);
    }
    void reset() { m_node.reset(); }
 
private:
    explicit iterator(not_null<std::shared_ptr<iterator_state<safety_level>>, safety_level> state)
        : m_state(std::move(state))
    {
        ++(*this); // Advance to the first node upon construction
    }
    not_null<std::shared_ptr<iterator_state<safety_level>>, safety_level> m_state;
    checked<std::optional<node_ref<safety_level>>, safety_level> m_node;
};
 
template<safety_policy safety_level>
nodes_view<safety_level> nodes(const node_ref<safety_level>& node)
{
    return nodes_view<safety_level>{node.state()};
}
 
template<safety_policy safety_level>
nodes_view<safety_level> nodes(reader<safety_level>& reader)
{
    return nodes_view<safety_level>{std::make_shared<iterator_state<safety_level>>(reader)};
}
 
}
 
#endif