Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,70 @@
+//------------------------------------------------------------------------------
+// <copyright file="IDQuery.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.Xml.Xsl;
+    using System.Diagnostics;
+    using System.Collections.Generic;
+
+    internal sealed class IDQuery : CacheOutputQuery {
+
+        public IDQuery(Query arg) : base(arg) {}
+        private IDQuery(IDQuery other) : base(other) { }
+
+        public override object Evaluate(XPathNodeIterator context) {
+            object argVal = base.Evaluate(context);
+            XPathNavigator contextNode = context.Current.Clone();
+
+            switch (GetXPathType(argVal)) {
+            case XPathResultType.NodeSet:
+                XPathNavigator temp;
+                while ((temp = input.Advance()) != null) {
+                    ProcessIds(contextNode, temp.Value);
+                }
+                break;
+            case XPathResultType.String:
+                ProcessIds(contextNode, (string)argVal);
+                break;
+            case XPathResultType.Number:
+                ProcessIds(contextNode, StringFunctions.toString((double)argVal));
+                break;
+            case XPathResultType.Boolean:
+                ProcessIds(contextNode, StringFunctions.toString((bool)argVal));
+                break;
+            case XPathResultType_Navigator:
+                ProcessIds(contextNode, ((XPathNavigator)argVal).Value);
+                break;
+            }
+            return this;
+        }
+
+        void ProcessIds(XPathNavigator contextNode, string val) {
+            string[] ids = XmlConvert.SplitString(val);
+            for (int idx = 0; idx < ids.Length; idx++) {
+                if (contextNode.MoveToId(ids[idx])) {
+                    Insert(outputBuffer, contextNode);
+                }
+            }
+        }
+
+        public override XPathNavigator MatchNode(XPathNavigator context) {
+            Evaluate(new XPathSingletonIterator(context, /*moved:*/true));
+            XPathNavigator result;
+            while ((result = Advance()) != null) {
+                if (result.IsSamePosition(context)) {
+                    return context;
+                }
+            }
+            return null;
+        }
+
+        public override XPathNodeIterator Clone() { return new IDQuery(this); }
+    }
+}