Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Data.SqlXml/System/Xml/Xsl/XsltOld/ChooseAction.cs

@@ -0,0 +1,80 @@
+//------------------------------------------------------------------------------
+// <copyright file="ChooseAction.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+// <owner current="true" primary="true">[....]</owner>
+//------------------------------------------------------------------------------
+
+namespace System.Xml.Xsl.XsltOld {
+    using Res = System.Xml.Utils.Res;
+    using System;
+    using System.Diagnostics;
+    using System.Xml;
+    using System.Xml.XPath;
+
+    internal class ChooseAction : ContainerAction {
+        internal override void Compile(Compiler compiler) {
+            CompileAttributes(compiler);
+
+            if (compiler.Recurse()) {
+                CompileConditions(compiler);
+                compiler.ToParent();
+            }
+        }
+
+        private void CompileConditions(Compiler compiler) {
+            NavigatorInput input = compiler.Input;
+            bool when       = false;
+            bool otherwise  = false;
+
+            do {
+                switch (input.NodeType) {
+                case XPathNodeType.Element:
+                    compiler.PushNamespaceScope();
+                    string nspace = input.NamespaceURI;
+                    string name   = input.LocalName;
+
+                    if (Ref.Equal(nspace, input.Atoms.UriXsl)) {
+                        IfAction action = null;
+                        if (Ref.Equal(name, input.Atoms.When)) {
+                            if (otherwise) {
+                                throw XsltException.Create(Res.Xslt_WhenAfterOtherwise);
+                            }
+                            action = compiler.CreateIfAction(IfAction.ConditionType.ConditionWhen);
+                            when = true;
+                        }
+                        else if (Ref.Equal(name, input.Atoms.Otherwise)) {
+                            if (otherwise) {
+                                throw XsltException.Create(Res.Xslt_DupOtherwise);
+                            }
+                            action = compiler.CreateIfAction(IfAction.ConditionType.ConditionOtherwise);
+                            otherwise = true;
+                        }
+                        else {
+                            throw compiler.UnexpectedKeyword();
+                        }
+                        AddAction(action);
+                    }
+                    else {
+                        throw compiler.UnexpectedKeyword();
+                    }
+                    compiler.PopScope();
+                    break;
+
+                case XPathNodeType.Comment:
+                case XPathNodeType.ProcessingInstruction:
+                case XPathNodeType.Whitespace:
+                case XPathNodeType.SignificantWhitespace:
+                    break;
+
+                default:
+                    throw XsltException.Create(Res.Xslt_InvalidContents, "choose");
+                }
+            }
+            while (compiler.Advance());
+            if (! when) {
+                throw XsltException.Create(Res.Xslt_NoWhen);
+            }
+        }
+    }
+}