Asttree.cs

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using System.Collections;
using System.Xml.XPath;
using MS.Internal.Xml.XPath;
 
namespace System.Xml.Schema;
 
internal sealed class Asttree
{
    private ArrayList _fAxisArray;
 
    private readonly string _xpathexpr;
 
    private readonly bool _isField;
 
    private readonly XmlNamespaceManager _nsmgr;
 
    internal ArrayList SubtreeArray => _fAxisArray;
 
    public Asttree(string xPath, bool isField, XmlNamespaceManager nsmgr)
    {
        _xpathexpr = xPath;
        _isField = isField;
        _nsmgr = nsmgr;
        CompileXPath(xPath, isField, nsmgr);
    }
 
    private static bool IsNameTest(Axis ast)
    {
        if (ast.TypeOfAxis == Axis.AxisType.Child)
        {
            return ast.NodeType == XPathNodeType.Element;
        }
        return false;
    }
 
    internal static bool IsAttribute(Axis ast)
    {
        if (ast.TypeOfAxis == Axis.AxisType.Attribute)
        {
            return ast.NodeType == XPathNodeType.Attribute;
        }
        return false;
    }
 
    private static bool IsDescendantOrSelf(Axis ast)
    {
        if (ast.TypeOfAxis == Axis.AxisType.DescendantOrSelf && ast.NodeType == XPathNodeType.All)
        {
            return ast.AbbrAxis;
        }
        return false;
    }
 
    internal static bool IsSelf(Axis ast)
    {
        if (ast.TypeOfAxis == Axis.AxisType.Self && ast.NodeType == XPathNodeType.All)
        {
            return ast.AbbrAxis;
        }
        return false;
    }
 
    public void CompileXPath(string xPath, bool isField, XmlNamespaceManager nsmgr)
    {
        if (xPath == null || xPath.Length == 0)
        {
            throw new XmlSchemaException(System.SR.Sch_EmptyXPath, string.Empty);
        }
        string[] array = xPath.Split('|');
        ArrayList arrayList = new ArrayList(array.Length);
        _fAxisArray = new ArrayList(array.Length);
        try
        {
            for (int i = 0; i < array.Length; i++)
            {
                Axis value = (Axis)XPathParser.ParseXPathExpression(array[i]);
                arrayList.Add(value);
            }
        }
        catch
        {
            throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
        }
        for (int j = 0; j < arrayList.Count; j++)
        {
            Axis axis = (Axis)arrayList[j];
            Axis axis2;
            if ((axis2 = axis) == null)
            {
                throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
            }
            Axis axis3 = axis2;
            if (IsAttribute(axis2))
            {
                if (!isField)
                {
                    throw new XmlSchemaException(System.SR.Sch_SelectorAttr, xPath);
                }
                SetURN(axis2, nsmgr);
                try
                {
                    axis2 = (Axis)axis2.Input;
                }
                catch
                {
                    throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
                }
            }
            while (axis2 != null && (IsNameTest(axis2) || IsSelf(axis2)))
            {
                if (IsSelf(axis2) && axis != axis2)
                {
                    axis3.Input = axis2.Input;
                }
                else
                {
                    axis3 = axis2;
                    if (IsNameTest(axis2))
                    {
                        SetURN(axis2, nsmgr);
                    }
                }
                try
                {
                    axis2 = (Axis)axis2.Input;
                }
                catch
                {
                    throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
                }
            }
            axis3.Input = null;
            if (axis2 == null)
            {
                if (IsSelf(axis) && axis.Input != null)
                {
                    _fAxisArray.Add(new ForwardAxis(DoubleLinkAxis.ConvertTree((Axis)axis.Input), isdesorself: false));
                }
                else
                {
                    _fAxisArray.Add(new ForwardAxis(DoubleLinkAxis.ConvertTree(axis), isdesorself: false));
                }
                continue;
            }
            if (!IsDescendantOrSelf(axis2))
            {
                throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
            }
            try
            {
                axis2 = (Axis)axis2.Input;
            }
            catch
            {
                throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
            }
            if (axis2 == null || !IsSelf(axis2) || axis2.Input != null)
            {
                throw new XmlSchemaException(System.SR.Sch_ICXpathError, xPath);
            }
            if (IsSelf(axis) && axis.Input != null)
            {
                _fAxisArray.Add(new ForwardAxis(DoubleLinkAxis.ConvertTree((Axis)axis.Input), isdesorself: true));
            }
            else
            {
                _fAxisArray.Add(new ForwardAxis(DoubleLinkAxis.ConvertTree(axis), isdesorself: true));
            }
        }
    }
 
    private void SetURN(Axis axis, XmlNamespaceManager nsmgr)
    {
        if (axis.Prefix.Length != 0)
        {
            axis.Urn = nsmgr.LookupNamespace(axis.Prefix);
            if (axis.Urn == null)
            {
                throw new XmlSchemaException(System.SR.Sch_UnresolvedPrefix, axis.Prefix);
            }
        }
        else if (axis.Name.Length != 0)
        {
            axis.Urn = null;
        }
        else
        {
            axis.Urn = "";
        }
    }
}