CompiledXpathExpr.cs

Go to the documentation of this file.

using System;
using System.Collections;
using System.Xml;
using System.Xml.XPath;
using System.Xml.Xsl;
 
namespace MS.Internal.Xml.XPath;
 
internal class CompiledXpathExpr : XPathExpression
{
    private sealed class UndefinedXsltContext : XsltContext
    {
        private readonly IXmlNamespaceResolver _nsResolver;
 
        public override string DefaultNamespace => string.Empty;
 
        public override bool Whitespace => false;
 
        public UndefinedXsltContext(IXmlNamespaceResolver nsResolver)
            : base(dummy: false)
        {
            _nsResolver = nsResolver;
        }
 
        public override string LookupNamespace(string prefix)
        {
            if (prefix.Length == 0)
            {
                return string.Empty;
            }
            string text = _nsResolver.LookupNamespace(prefix);
            if (text == null)
            {
                throw XPathException.Create(System.SR.XmlUndefinedAlias, prefix);
            }
            return text;
        }
 
        public override IXsltContextVariable ResolveVariable(string prefix, string name)
        {
            throw XPathException.Create(System.SR.Xp_UndefinedXsltContext);
        }
 
        public override IXsltContextFunction ResolveFunction(string prefix, string name, XPathResultType[] ArgTypes)
        {
            throw XPathException.Create(System.SR.Xp_UndefinedXsltContext);
        }
 
        public override bool PreserveWhitespace(XPathNavigator node)
        {
            return false;
        }
 
        public override int CompareDocument(string baseUri, string nextbaseUri)
        {
            return string.CompareOrdinal(baseUri, nextbaseUri);
        }
    }
 
    private Query _query;
 
    private readonly string _expr;
 
    private bool _needContext;
 
    internal Query QueryTree
    {
        get
        {
            if (_needContext)
            {
                throw XPathException.Create(System.SR.Xp_NoContext);
            }
            return _query;
        }
    }
 
    public override string Expression => _expr;
 
    public override XPathResultType ReturnType => _query.StaticType;
 
    internal CompiledXpathExpr(Query query, string expression, bool needContext)
    {
        _query = query;
        _expr = expression;
        _needContext = needContext;
    }
 
    public virtual void CheckErrors()
    {
    }
 
    public override void AddSort(object expr, IComparer comparer)
    {
        Query evalQuery;
        if (expr is string query)
        {
            evalQuery = new QueryBuilder().Build(query, out _needContext);
        }
        else
        {
            if (!(expr is CompiledXpathExpr compiledXpathExpr))
            {
                throw XPathException.Create(System.SR.Xp_BadQueryObject);
            }
            evalQuery = compiledXpathExpr.QueryTree;
        }
        SortQuery sortQuery = _query as SortQuery;
        if (sortQuery == null)
        {
            sortQuery = (SortQuery)(_query = new SortQuery(_query));
        }
        sortQuery.AddSort(evalQuery, comparer);
    }
 
    public override void AddSort(object expr, XmlSortOrder order, XmlCaseOrder caseOrder, string lang, XmlDataType dataType)
    {
        AddSort(expr, new XPathComparerHelper(order, caseOrder, lang, dataType));
    }
 
    public override XPathExpression Clone()
    {
        return new CompiledXpathExpr(Query.Clone(_query), _expr, _needContext);
    }
 
    public override void SetContext(XmlNamespaceManager nsManager)
    {
        SetContext((IXmlNamespaceResolver?)nsManager);
    }
 
    public override void SetContext(IXmlNamespaceResolver nsResolver)
    {
        XsltContext xsltContext = nsResolver as XsltContext;
        if (xsltContext == null)
        {
            if (nsResolver == null)
            {
                nsResolver = new XmlNamespaceManager(new NameTable());
            }
            xsltContext = new UndefinedXsltContext(nsResolver);
        }
        _query.SetXsltContext(xsltContext);
        _needContext = false;
    }
}