Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Xml/System/Xml/Schema/ParserAsync.cs

@@ -0,0 +1,59 @@
+
+namespace System.Xml.Schema {
+
+    using System;
+    using System.Collections;
+    using System.Globalization;
+    using System.Text;
+    using System.IO;
+    using System.Diagnostics;
+
+        using System.Threading.Tasks;
+    
+    internal sealed partial class Parser {
+
+        public async Task< SchemaType > ParseAsync(XmlReader reader, string targetNamespace) {
+            await StartParsingAsync(reader, targetNamespace).ConfigureAwait(false);
+            while(ParseReaderNode() && await reader.ReadAsync().ConfigureAwait(false)) {}
+            return FinishParsing();
+        }
+
+        public async Task StartParsingAsync(XmlReader reader, string targetNamespace) {
+            this.reader = reader;
+            positionInfo = PositionInfo.GetPositionInfo(reader);
+            namespaceManager = reader.NamespaceManager;
+            if (namespaceManager == null) {
+                namespaceManager = new XmlNamespaceManager(nameTable);
+                isProcessNamespaces = true;
+            } 
+            else {
+                isProcessNamespaces = false;
+            }
+            while (reader.NodeType != XmlNodeType.Element && await reader.ReadAsync().ConfigureAwait(false)) {}
+
+            markupDepth = int.MaxValue;
+            schemaXmlDepth = reader.Depth;
+            SchemaType rootType = schemaNames.SchemaTypeFromRoot(reader.LocalName, reader.NamespaceURI);
+            
+            string code;
+            if (!CheckSchemaRoot(rootType, out code)) {
+                throw new XmlSchemaException(code, reader.BaseURI, positionInfo.LineNumber, positionInfo.LinePosition);
+            }
+            
+            if (schemaType == SchemaType.XSD) {
+                schema = new XmlSchema();
+                schema.BaseUri = new Uri(reader.BaseURI, UriKind.RelativeOrAbsolute);
+                builder = new XsdBuilder(reader, namespaceManager, schema, nameTable, schemaNames, eventHandler);
+            }
+            else {  
+                Debug.Assert(schemaType == SchemaType.XDR);
+                xdrSchema = new SchemaInfo();
+                xdrSchema.SchemaType = SchemaType.XDR;
+                builder = new XdrBuilder(reader, namespaceManager, xdrSchema, targetNamespace, nameTable, schemaNames, eventHandler);
+                ((XdrBuilder)builder).XmlResolver = xmlResolver;
+            }
+        }
+
+    };
+
+} // namespace System.Xml