Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Xml/System/Xml/XPath/Internal/VariableQuery.cs

@@ -0,0 +1,67 @@
+//------------------------------------------------------------------------------
+// <copyright file="VariableQuery.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+// <owner current="true" primary="true">[....]</owner>
+//------------------------------------------------------------------------------
+
+namespace MS.Internal.Xml.XPath {
+    using System;
+    using System.Xml;
+    using System.Xml.XPath;
+    using System.Diagnostics;
+    using System.Globalization;
+    using System.Xml.Xsl;
+
+    internal sealed class VariableQuery : ExtensionQuery {
+        private IXsltContextVariable variable;
+
+        public VariableQuery(string name, string prefix) : base(prefix, name) {}
+        private VariableQuery(VariableQuery other) : base(other) {
+            this.variable = other.variable;
+        }
+
+        public override void SetXsltContext(XsltContext context) {
+            if (context == null) {
+                throw XPathException.Create(Res.Xp_NoContext);
+            }
+
+			if (this.xsltContext != context) {
+                xsltContext = context;
+				variable = xsltContext.ResolveVariable(prefix, name);
+                // Since null is allowed for ResolveFunction, allow it for ResolveVariable as well
+                if (variable == null) {
+                    throw XPathException.Create(Res.Xp_UndefVar, QName);
+                }
+            }
+        }
+
+        public override object Evaluate(XPathNodeIterator nodeIterator) {
+			if (xsltContext == null) {
+				throw XPathException.Create(Res.Xp_NoContext);
+			}
+
+            return ProcessResult(variable.Evaluate(xsltContext));
+        }
+
+        public override XPathResultType StaticType { get {
+            if (variable != null) {  // Temp. fix to overcome dependency on static type
+                return GetXPathType(Evaluate(null));
+            }
+            XPathResultType result = variable != null ? variable.VariableType : XPathResultType.Any;
+			if (result == XPathResultType.Error) {
+				// In v.1 we confused Error & Any so now for backward compatibility we should allow users to return any of them.
+				result = XPathResultType.Any;
+			}
+            return result;
+        } }
+
+        public override XPathNodeIterator Clone() { return new VariableQuery(this); }
+
+        public override void PrintQuery(XmlWriter w) {
+            w.WriteStartElement(this.GetType().Name);
+            w.WriteAttributeString("name", prefix.Length != 0 ? prefix + ':' + name : name);
+            w.WriteEndElement();
+        }
+    }
+}