MergeFilterQuery.cs

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using System.Xml.XPath;
using System.Xml.Xsl;
 
namespace MS.Internal.Xml.XPath;
 
internal sealed class MergeFilterQuery : CacheOutputQuery
{
    private readonly Query _child;
 
    public MergeFilterQuery(Query input, Query child)
        : base(input)
    {
        _child = child;
    }
 
    private MergeFilterQuery(MergeFilterQuery other)
        : base(other)
    {
        _child = Query.Clone(other._child);
    }
 
    public override void SetXsltContext(XsltContext xsltContext)
    {
        base.SetXsltContext(xsltContext);
        _child.SetXsltContext(xsltContext);
    }
 
    public override object Evaluate(XPathNodeIterator nodeIterator)
    {
        base.Evaluate(nodeIterator);
        while (input.Advance() != null)
        {
            _child.Evaluate(input);
            XPathNavigator nav;
            while ((nav = _child.Advance()) != null)
            {
                Query.Insert(outputBuffer, nav);
            }
        }
        return this;
    }
 
    public override XPathNavigator MatchNode(XPathNavigator current)
    {
        XPathNavigator xPathNavigator = _child.MatchNode(current);
        if (xPathNavigator == null)
        {
            return null;
        }
        xPathNavigator = input.MatchNode(xPathNavigator);
        if (xPathNavigator == null)
        {
            return null;
        }
        Evaluate(new XPathSingletonIterator(xPathNavigator.Clone(), moved: true));
        for (XPathNavigator xPathNavigator2 = Advance(); xPathNavigator2 != null; xPathNavigator2 = Advance())
        {
            if (xPathNavigator2.IsSamePosition(current))
            {
                return xPathNavigator;
            }
        }
        return null;
    }
 
    public override XPathNodeIterator Clone()
    {
        return new MergeFilterQuery(this);
    }
}