XPathDocumentElementDescendantIterator.cs

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using System;
using System.Xml.XPath;
 
namespace MS.Internal.Xml.Cache;
 
internal sealed class XPathDocumentElementDescendantIterator : XPathDocumentBaseIterator
{
    private readonly XPathDocumentNavigator _end;
 
    private readonly string _localName;
 
    private readonly string _namespaceUri;
 
    private bool _matchSelf;
 
    public XPathDocumentElementDescendantIterator(XPathDocumentNavigator root, string name, string namespaceURI, bool matchSelf)
        : base(root)
    {
        if (namespaceURI == null)
        {
            throw new ArgumentNullException("namespaceURI");
        }
        _localName = root.NameTable.Get(name);
        _namespaceUri = namespaceURI;
        _matchSelf = matchSelf;
        if (root.NodeType != 0)
        {
            _end = new XPathDocumentNavigator(root);
            _end.MoveToNonDescendant();
        }
    }
 
    public XPathDocumentElementDescendantIterator(XPathDocumentElementDescendantIterator iter)
        : base(iter)
    {
        _end = iter._end;
        _localName = iter._localName;
        _namespaceUri = iter._namespaceUri;
        _matchSelf = iter._matchSelf;
    }
 
    public override XPathNodeIterator Clone()
    {
        return new XPathDocumentElementDescendantIterator(this);
    }
 
    public override bool MoveNext()
    {
        if (_matchSelf)
        {
            _matchSelf = false;
            if (ctxt.IsElementMatch(_localName, _namespaceUri))
            {
                pos++;
                return true;
            }
        }
        if (!ctxt.MoveToFollowing(_localName, _namespaceUri, _end))
        {
            return false;
        }
        pos++;
        return true;
    }
}