<?xml version="1.0"?>
<!--這是注釋-->
<workflow>
    <work name="1" switch="on">
        <plugin name="echoplugin.so" switch="on" />
    </work>
</workflow>

namespace xml
{
    using std::vector;
    using std::map;
    using std::string_view;
    using std::string;
    class Element
    {
    public:
        using children_t = vector<Element>;
        using attrs_t = map<string, string>;
        using iterator = vector<Element>::iterator;
        using const_iterator = vector<Element>::const_iterator;
        string &Name()
        {
            return m_name;
        }
        string &Text()
        {
            return m_text;
        }
        //迭代器方便遍歷子節(jié)點(diǎn)
        iterator begin()
        {
            return m_children.begin();
        }
        [[nodiscard]] const_iterator begin() const
        {
            return m_children.begin();
        }
        iterator end()
        {
            return m_children.end();
        }
        [[nodiscard]] const_iterator end() const
        {
            return m_children.end();
        }
        void push_back(Element const &element)//方便子節(jié)點(diǎn)的存入
        {
            m_children.push_back(element);
        }
        string &operator[](string const &key) //方便key-value的存取
        {
            return m_attrs[key];
        }
        string to_string()
        {
            return _to_string();
        }
    private:
        string _to_string();
    private:
        string m_name;
        string m_text;
        children_t m_children;
        attrs_t m_attrs;
    };
}

Element xml::Parser::Parse()
{
    while (true)
    {
        char t = _get_next_token();
        if (t != '<')
        {
            THROW_ERROR("invalid format", m_str.substr(m_idx, detail_len));
        }
        //解析版本號(hào)
        if (m_idx + 4 < m_str.size() && m_str.compare(m_idx, 5, "<?xml") == 0)
        {
            if (!_parse_version())
            {
                THROW_ERROR("version parse error", m_str.substr(m_idx, detail_len));
            }
            continue;
        }
        //解析注釋
        if (m_idx + 3 < m_str.size() && m_str.compare(m_idx, 4, "<!--") == 0)
        {
            if (!_parse_comment())
            {
                THROW_ERROR("comment parse error", m_str.substr(m_idx, detail_len));
            }
            continue;
        }
        //解析element
        if (m_idx + 1 < m_str.size() && (isalpha(m_str[m_idx + 1]) || m_str[m_idx + 1] == '_'))
        {
            return _parse_element();
        }
        //出現(xiàn)未定義情況直接拋出異常
        THROW_ERROR("error format", m_str.substr(m_idx, detail_len));
    }
}

Element xml::Parser::_parse_element()
{
    Element element;
    auto pre_pos = ++m_idx; //過(guò)掉<
    //判斷name首字符合法性
    if (!(m_idx < m_str.size() && (std::isalpha(m_str[m_idx]) || m_str[m_idx] == '_')))
    {
        THROW_ERROR("error occur in parse name", m_str.substr(m_idx, detail_len));
    }
    //解析name
    while (m_idx < m_str.size() && (isalpha(m_str[m_idx]) || m_str[m_idx] == ':' ||
                                    m_str[m_idx] == '-' || m_str[m_idx] == '_' || m_str[m_idx] == '.'))
    {
        m_idx++;
    }
    if (m_idx >= m_str.size())
        THROW_ERROR("error occur in parse name", m_str.substr(m_idx, detail_len));
    element.Name() = m_str.substr(pre_pos, m_idx - pre_pos);
    //正式解析內(nèi)部
    while (m_idx < m_str.size())
    {
        char token = _get_next_token();
        if (token == '/') //1.單元素，直接解析后結(jié)束
        {
            if (m_str[m_idx + 1] == '>')
            {
                m_idx += 2;
                return element;
            } else
            {
                THROW_ERROR("parse single_element failed", m_str.substr(m_idx, detail_len));
            }
        }
        if (token == '<')//2.對(duì)應(yīng)三種情況：結(jié)束符、注釋、下個(gè)子節(jié)點(diǎn)
        {
            //結(jié)束符
            if (m_str[m_idx + 1] == '/')
            {
                if (m_str.compare(m_idx + 2, element.Name().size(), element.Name()) != 0)
                {
                    THROW_ERROR("parse end tag error", m_str.substr(m_idx, detail_len));
                }
                m_idx += 2 + element.Name().size();
                char x = _get_next_token();
                if (x != '>')
                {
                    THROW_ERROR("parse end tag error", m_str.substr(m_idx, detail_len));
                }
                m_idx++; //千萬(wàn)注意把 '>' 過(guò)掉，防止下次解析被識(shí)別為初始的tag結(jié)束，實(shí)際上這個(gè)element已經(jīng)解析完成
                return element;
            }
            //是注釋的情況
            if (m_idx + 3 < m_str.size() && m_str.compare(m_idx, 4, "<!--") == 0)
            {
                if (!_parse_comment())
                {
                    THROW_ERROR("parse comment error", m_str.substr(m_idx, detail_len));
                }
                continue;
            }
            //其余情況可能是注釋或子元素，直接調(diào)用parse進(jìn)行解析得到即可
            element.push_back(Parse());
            continue;
        }
        if (token == '>') //3.對(duì)應(yīng)兩種情況：該標(biāo)簽的text內(nèi)容，下個(gè)標(biāo)簽的開(kāi)始或者注釋（直接continue跳到到下次循環(huán)即可
        {
            m_idx++;
            //判斷下個(gè)token是否為text，如果不是則continue
            char x = _get_next_token();
            if (x == '<')//不可能是結(jié)束符，因?yàn)閤ml元素不能為空body，如果直接出現(xiàn)這種情況也有可能是中間夾雜了注釋
            {
                continue;
            }
            //解析text再解析child
            auto pos = m_str.find('<', m_idx);
            if (pos == string::npos)
                THROW_ERROR("parse text error", m_str.substr(m_idx, detail_len));
            element.Text() = m_str.substr(m_idx, pos - m_idx);
            m_idx = pos;
            //注意：有可能直接碰上結(jié)束符，所以需要continue，讓element里的邏輯來(lái)進(jìn)行判斷
            continue;
        }
        //4.其余情況都為屬性的解析
        auto key = _parse_attr_key();
        auto x = _get_next_token();
        if (x != '=')
        {
            THROW_ERROR("parse attrs error", m_str.substr(m_idx, detail_len));
        }
        m_idx++;
        auto value = _parse_attr_value();
        element[key] = value;
    }
    THROW_ERROR("parse element error", m_str.substr(m_idx, detail_len));
}

//用于返回較為詳細(xì)的錯(cuò)誤信息，方便錯(cuò)誤追蹤
#define THROW_ERROR(error_info, error_detail) \
    do{                                    \
    string info = "parse error in ";              \
    string file_pos = __FILE__;                          \
    file_pos.append(":");                                \
    file_pos.append(std::to_string(__LINE__));\
    info += file_pos;                                  \
    info += ", ";                          \
    info += (error_info);                    \
    info += "\ndetail:";                          \
    info += (error_detail);\
    throw std::logic_error(info); \
}while(false)

class Data{
    ...
}
class test{
pvivate:
    Data m_data;
}

class Data{
    ...
}
class test{
public:
    //拷貝構(gòu)造
    test(test const&src) = default;//等價(jià)于下面的代碼
    //test(test const& src):m_data(src.m_data){}
    //移動(dòng)構(gòu)造
    test(test &&src) = default;//等價(jià)于下面代碼
    //tset(test&& src):m_data(std::move(src.m_data)){}
pvivate:
    Data m_data;
}

class Data{
    ...
}
class test{
pvivate:
    Data m_data;
}