PreSiblingQuery.cs

Go to the documentation of this file.

using System.Collections.Generic;
using System.Xml.XPath;
 
namespace MS.Internal.Xml.XPath;
 
internal sealed class PreSiblingQuery : CacheAxisQuery
{
    public override QueryProps Properties => base.Properties | QueryProps.Reverse;
 
    public PreSiblingQuery(Query qyInput, string name, string prefix, XPathNodeType typeTest)
        : base(qyInput, name, prefix, typeTest)
    {
    }
 
    private PreSiblingQuery(PreSiblingQuery other)
        : base(other)
    {
    }
 
    private static bool NotVisited(XPathNavigator nav, List<XPathNavigator> parentStk)
    {
        XPathNavigator xPathNavigator = nav.Clone();
        xPathNavigator.MoveToParent();
        for (int i = 0; i < parentStk.Count; i++)
        {
            if (xPathNavigator.IsSamePosition(parentStk[i]))
            {
                return false;
            }
        }
        parentStk.Add(xPathNavigator);
        return true;
    }
 
    public override object Evaluate(XPathNodeIterator context)
    {
        base.Evaluate(context);
        List<XPathNavigator> parentStk = new List<XPathNavigator>();
        Stack<XPathNavigator> stack = new Stack<XPathNavigator>();
        while ((currentNode = qyInput.Advance()) != null)
        {
            stack.Push(currentNode.Clone());
        }
        while (stack.Count != 0)
        {
            XPathNavigator xPathNavigator = stack.Pop();
            if (xPathNavigator.NodeType == XPathNodeType.Attribute || xPathNavigator.NodeType == XPathNodeType.Namespace || !NotVisited(xPathNavigator, parentStk))
            {
                continue;
            }
            XPathNavigator xPathNavigator2 = xPathNavigator.Clone();
            if (!xPathNavigator2.MoveToParent())
            {
                continue;
            }
            bool flag = xPathNavigator2.MoveToFirstChild();
            while (!xPathNavigator2.IsSamePosition(xPathNavigator))
            {
                if (matches(xPathNavigator2))
                {
                    Query.Insert(outputBuffer, xPathNavigator2);
                }
                if (!xPathNavigator2.MoveToNext())
                {
                    break;
                }
            }
        }
        return this;
    }
 
    public override XPathNodeIterator Clone()
    {
        return new PreSiblingQuery(this);
    }
}