Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Configuration/System/Configuration/ConfigXmlReader.cs

@@ -0,0 +1,77 @@
+//------------------------------------------------------------------------------
+// <copyright file="ConfigXmlReader.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Configuration {
+    using System.Configuration.Internal;
+    using System.Collections;
+    using System.Collections.Specialized;
+    using System.Collections.Generic;
+    using System.Configuration;
+    using System.Globalization;
+    using System.IO;
+    using System.Runtime.InteropServices;
+    using System.Security;
+    using System.Security.Permissions;
+    using System.Text;
+    using System.Xml;
+    using System.Net;
+
+    internal sealed class ConfigXmlReader : XmlTextReader, IConfigErrorInfo {
+        string  _rawXml;
+        int     _lineOffset;
+        string  _filename;
+
+        // Used in a decrypted configuration section to locate
+        // the line where the ecnrypted section begins.
+        bool    _lineNumberIsConstant;
+
+        internal ConfigXmlReader(string rawXml, string filename, int lineOffset) : 
+                this(rawXml, filename, lineOffset, false) {
+        }
+
+        internal ConfigXmlReader(string rawXml, string filename, int lineOffset, bool lineNumberIsConstant) : 
+                base(new StringReader(rawXml)) {
+
+            _rawXml = rawXml;
+            _filename = filename;
+            _lineOffset = lineOffset;
+            _lineNumberIsConstant = lineNumberIsConstant;
+
+            Debug.Assert(!_lineNumberIsConstant || _lineOffset > 0, 
+                        "!_lineNumberIsConstant || _lineOffset > 0");
+        }
+
+        internal ConfigXmlReader Clone() {
+            return new ConfigXmlReader(_rawXml, _filename, _lineOffset, _lineNumberIsConstant);
+        }
+
+        int IConfigErrorInfo.LineNumber {
+            get {
+                if (_lineNumberIsConstant) {
+                    return _lineOffset;
+                }
+                else if (_lineOffset > 0) {
+                    return base.LineNumber + (_lineOffset - 1);
+                }
+                else {
+                    return base.LineNumber;
+                }
+            }
+        }
+    
+        string IConfigErrorInfo.Filename {
+            get {
+                return _filename;
+            }
+        }
+
+        internal string RawXml {
+            get {
+                return _rawXml;
+            }
+        }
+    }
+}