XPathDescendantIterator.cs

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using System.Xml.XPath;
 
namespace MS.Internal.Xml.XPath;
 
internal sealed class XPathDescendantIterator : XPathAxisIterator
{
    private int _level;
 
    public XPathDescendantIterator(XPathNavigator nav, XPathNodeType type, bool matchSelf)
        : base(nav, type, matchSelf)
    {
    }
 
    public XPathDescendantIterator(XPathNavigator nav, string name, string namespaceURI, bool matchSelf)
        : base(nav, name, namespaceURI, matchSelf)
    {
    }
 
    public XPathDescendantIterator(XPathDescendantIterator it)
        : base(it)
    {
        _level = it._level;
    }
 
    public override XPathNodeIterator Clone()
    {
        return new XPathDescendantIterator(this);
    }
 
    public override bool MoveNext()
    {
        if (_level == -1)
        {
            return false;
        }
        if (first)
        {
            first = false;
            if (matchSelf && Matches)
            {
                position = 1;
                return true;
            }
        }
        do
        {
            if (nav.MoveToFirstChild())
            {
                _level++;
                continue;
            }
            while (true)
            {
                if (_level == 0)
                {
                    _level = -1;
                    return false;
                }
                if (nav.MoveToNext())
                {
                    break;
                }
                nav.MoveToParent();
                _level--;
            }
        }
        while (!Matches);
        position++;
        return true;
    }
}