[mono-api-info] Use XmlWriter instead of XmlDocument to make this faster.
authorRolf Bjarne Kvinge <rolf@xamarin.com>
Wed, 27 Jan 2016 11:56:23 +0000 (12:56 +0100)
committerRolf Bjarne Kvinge <rolf@xamarin.com>
Thu, 28 Jan 2016 13:48:57 +0000 (14:48 +0100)
Generating all the API references (in parallel) for Xamarin.iOS goes from
5.5s to 4.5s.

mcs/tools/corcompare/mono-api-info.cs

index 0886d14b3bd47e82cb738b811dcbf55ced3ef7de..29cc3e58a6df17c6ee108a10842dc9ad391aa6fa 100644 (file)
@@ -93,18 +93,20 @@ namespace CorCompare
                                }
                        }
 
-                       XmlDocument doc = new XmlDocument ();
-                       acoll.Document = doc;
-                       acoll.DoOutput ();
-
-                       TextWriter outputStream = null;
+                       StreamWriter outputStream = null;
                        if (!string.IsNullOrEmpty (output))
                                outputStream = new StreamWriter (output);
                        try {
-                               var writer = new WellFormedXmlWriter (new XmlTextWriter (outputStream ?? Console.Out) { Formatting = Formatting.Indented });
-                               XmlNode decl = doc.CreateXmlDeclaration ("1.0", "utf-8", null);
-                               doc.InsertBefore (decl, doc.DocumentElement);
-                               doc.WriteTo (writer);
+                               TextWriter outStream = outputStream ?? Console.Out;
+                               var settings = new XmlWriterSettings ();
+                               settings.Indent = true;
+                               var textWriter = XmlWriter.Create (outStream, settings);
+                               var writer = new WellFormedXmlWriter (textWriter);
+                               writer.WriteStartDocument ();
+                               acoll.Writer = writer;
+                               acoll.DoOutput ();
+                               writer.WriteEndDocument ();
+                               writer.Flush ();
                        } finally {
                                if (outputStream != null)
                                        outputStream.Dispose ();
@@ -131,7 +133,7 @@ namespace CorCompare
 
        class AssemblyCollection
        {
-               XmlDocument document;
+               XmlWriter writer;
                List<AssemblyDefinition> assemblies = new List<AssemblyDefinition> ();
 
                public AssemblyCollection ()
@@ -152,19 +154,19 @@ namespace CorCompare
 
                public void DoOutput ()
                {
-                       if (document == null)
+                       if (writer == null)
                                throw new InvalidOperationException ("Document not set");
 
-                       XmlNode nassemblies = document.CreateElement ("assemblies", null);
-                       document.AppendChild (nassemblies);
+                       writer.WriteStartElement ("assemblies");
                        foreach (AssemblyDefinition a in assemblies) {
-                               AssemblyData data = new AssemblyData (document, nassemblies, a);
+                               AssemblyData data = new AssemblyData (writer, a);
                                data.DoOutput ();
                        }
+                       writer.WriteEndElement ();
                }
 
-               public XmlDocument Document {
-                       set { document = value; }
+               public XmlWriter Writer {
+                       set { writer = value; }
                }
 
                AssemblyDefinition LoadAssembly (string assembly)
@@ -183,22 +185,18 @@ namespace CorCompare
 
        abstract class BaseData
        {
-               protected XmlDocument document;
-               protected XmlNode parent;
+               protected XmlWriter writer;
 
-               protected BaseData (XmlDocument doc, XmlNode parent)
+               protected BaseData (XmlWriter writer)
                {
-                       this.document = doc;
-                       this.parent = parent;
+                       this.writer = writer;
                }
 
                public abstract void DoOutput ();
 
-               protected void AddAttribute (XmlNode node, string name, string value)
+               protected void AddAttribute (string name, string value)
                {
-                       XmlAttribute attr = document.CreateAttribute (name);
-                       attr.Value = value;
-                       node.Attributes.Append (attr);
+                       writer.WriteAttributeString (name, value);
                }
        }
 
@@ -206,38 +204,34 @@ namespace CorCompare
        {
                AssemblyDefinition ass;
 
-               public TypeForwardedToData (XmlDocument document, XmlNode parent, AssemblyDefinition ass)
-                       : base (document, parent)
+               public TypeForwardedToData (XmlWriter writer, AssemblyDefinition ass)
+                       : base (writer)
                {
                        this.ass = ass;
                }
 
                public override void DoOutput ()
                {
-                       XmlNode natts = parent.SelectSingleNode("attributes");
-                       if (natts == null) {
-                               natts = document.CreateElement ("attributes", null);
-                               parent.AppendChild (natts);
-                       }
-
                        foreach (ExportedType type in ass.MainModule.ExportedTypes) {
 
                                if (((uint)type.Attributes & 0x200000u) == 0)
                                        continue;
 
-                               XmlNode node = document.CreateElement ("attribute");
-                               AddAttribute (node, "name", typeof (TypeForwardedToAttribute).FullName);
-                               XmlNode properties = node.AppendChild (document.CreateElement ("properties"));
-                               XmlNode property = properties.AppendChild (document.CreateElement ("property"));
-                               AddAttribute (property, "name", "Destination");
-                               AddAttribute (property, "value", Utils.CleanupTypeName (type.FullName));
-                               natts.AppendChild (node);
+                               writer.WriteStartElement ("attribute");
+                               AddAttribute ("name", typeof (TypeForwardedToAttribute).FullName);
+                               writer.WriteStartElement ("properties");
+                               writer.WriteStartElement ("property");
+                               AddAttribute ("name", "Destination");
+                               AddAttribute ("value", Utils.CleanupTypeName (type.FullName));
+                               writer.WriteEndElement (); // properties
+                               writer.WriteEndElement (); // properties
+                               writer.WriteEndElement (); // attribute
                        }
                }
 
-               public static void OutputForwarders (XmlDocument document, XmlNode parent, AssemblyDefinition ass)
+               public static void OutputForwarders (XmlWriter writer, AssemblyDefinition ass)
                {
-                       TypeForwardedToData tftd = new TypeForwardedToData (document, parent, ass);
+                       TypeForwardedToData tftd = new TypeForwardedToData (writer, ass);
                        tftd.DoOutput ();
                }
        }
@@ -246,28 +240,23 @@ namespace CorCompare
        {
                AssemblyDefinition ass;
 
-               public AssemblyData (XmlDocument document, XmlNode parent, AssemblyDefinition ass)
-                       : base (document, parent)
+               public AssemblyData (XmlWriter writer, AssemblyDefinition ass)
+                       : base (writer)
                {
                        this.ass = ass;
                }
 
                public override void DoOutput ()
                {
-                       if (document == null)
+                       if (writer == null)
                                throw new InvalidOperationException ("Document not set");
 
-                       XmlNode nassembly = document.CreateElement ("assembly", null);
+                       writer.WriteStartElement ("assembly");
                        AssemblyNameDefinition aname = ass.Name;
-                       AddAttribute (nassembly, "name", aname.Name);
-                       AddAttribute (nassembly, "version", aname.Version.ToString ());
-                       parent.AppendChild (nassembly);
+                       AddAttribute ("name", aname.Name);
+                       AddAttribute ("version", aname.Version.ToString ());
 
-                       if (!Driver.FollowForwarders) {
-                               TypeForwardedToData.OutputForwarders (document, nassembly, ass);
-                       }
-
-                       AttributeData.OutputAttributes (document, nassembly, ass);
+                       AttributeData.OutputAttributes (writer, ass);
 
                        var types = new List<TypeDefinition> ();
                        if (ass.MainModule.Types != null) {
@@ -285,17 +274,16 @@ namespace CorCompare
                        }
 
                        if (types.Count == 0) {
+                               writer.WriteEndElement (); // assembly
                                return;
                        }
 
                        types.Sort (TypeReferenceComparer.Default);
 
-                       XmlNode nss = document.CreateElement ("namespaces", null);
-                       nassembly.AppendChild (nss);
+                       writer.WriteStartElement ("namespaces");
 
                        string current_namespace = "$%&$&";
-                       XmlNode ns = null;
-                       XmlNode classes = null;
+                       bool in_namespace = false;
                        foreach (TypeDefinition t in types) {
                                if (string.IsNullOrEmpty (t.Namespace))
                                        continue;
@@ -308,16 +296,30 @@ namespace CorCompare
 
                                if (t.Namespace != current_namespace) {
                                        current_namespace = t.Namespace;
-                                       ns = document.CreateElement ("namespace", null);
-                                       AddAttribute (ns, "name", current_namespace);
-                                       nss.AppendChild (ns);
-                                       classes = document.CreateElement ("classes", null);
-                                       ns.AppendChild (classes);
+                                       if (in_namespace) {
+                                               writer.WriteEndElement (); // classes
+                                               writer.WriteEndElement (); // namespace
+                                       } else {
+                                               in_namespace = true;
+                                       }
+                                       writer.WriteStartElement ("namespace");
+                                       AddAttribute ("name", current_namespace);
+                                       writer.WriteStartElement ("classes");
                                }
 
-                               TypeData bd = new TypeData (document, classes, t);
+                               TypeData bd = new TypeData (writer, t);
                                bd.DoOutput ();
+
+                       }
+
+                       if (in_namespace) {
+                               writer.WriteEndElement (); // classes
+                               writer.WriteEndElement (); // namespace
                        }
+
+                       writer.WriteEndElement (); // namespaces
+
+                       writer.WriteEndElement (); // assembly
                }
        }
 
@@ -325,31 +327,42 @@ namespace CorCompare
        {
                MemberReference [] members;
 
-               public MemberData (XmlDocument document, XmlNode parent, MemberReference [] members)
-                       : base (document, parent)
+               public MemberData (XmlWriter writer, MemberReference [] members)
+                       : base (writer)
                {
                        this.members = members;
                }
 
+               protected virtual ICustomAttributeProvider GetAdditionalCustomAttributeProvider (MemberReference member)
+               {
+                       return null;
+               }
+
                public override void DoOutput ()
                {
-                       XmlNode mclass = document.CreateElement (ParentTag, null);
-                       parent.AppendChild (mclass);
+                       writer.WriteStartElement (ParentTag);
 
                        foreach (MemberReference member in members) {
-                               XmlNode mnode = document.CreateElement (Tag, null);
-                               mclass.AppendChild (mnode);
-                               AddAttribute (mnode, "name", GetName (member));
+                               writer.WriteStartElement (Tag);
+                               AddAttribute ("name", GetName (member));
                                if (!NoMemberAttributes)
-                                       AddAttribute (mnode, "attrib", GetMemberAttributes (member));
+                                       AddAttribute ("attrib", GetMemberAttributes (member));
+                               AddExtraAttributes (member);
 
-                               AttributeData.OutputAttributes (document, mnode, (ICustomAttributeProvider) member);
+                               AttributeData.OutputAttributes (writer, (ICustomAttributeProvider) member, GetAdditionalCustomAttributeProvider (member));
 
-                               AddExtraData (mnode, member);
+                               AddExtraData (member);
+                               writer.WriteEndElement (); // Tag
                        }
+
+                       writer.WriteEndElement (); // ParentTag
                }
 
-               protected virtual void AddExtraData (XmlNode p, MemberReference memberDefenition)
+               protected virtual void AddExtraData (MemberReference memberDefenition)
+               {
+               }
+
+               protected virtual void AddExtraAttributes (MemberReference memberDefinition)
                {
                }
 
@@ -376,39 +389,42 @@ namespace CorCompare
                        get { return "NoTAG"; }
                }
 
-               public static void OutputGenericParameters (XmlDocument document, XmlNode nclass, IGenericParameterProvider provider)
+               public static void OutputGenericParameters (XmlWriter writer, IGenericParameterProvider provider)
                {
                        if (provider.GenericParameters.Count == 0)
                                return;
 
                        var gparameters = provider.GenericParameters;
 
-                       XmlElement ngeneric = document.CreateElement ("generic-parameters");
-                       nclass.AppendChild (ngeneric);
+                       writer.WriteStartElement ("generic-parameters");
 
                        foreach (GenericParameter gp in gparameters) {
-                               XmlElement nparam = document.CreateElement ("generic-parameter");
-                               nparam.SetAttribute ("name", gp.Name);
-                               nparam.SetAttribute ("attributes", ((int) gp.Attributes).ToString ());
-
-                               AttributeData.OutputAttributes (document, nparam, gp);
+                               writer.WriteStartElement ("generic-parameter");
+                               writer.WriteAttributeString ("name", gp.Name);
+                               writer.WriteAttributeString ("attributes", ((int) gp.Attributes).ToString ());
 
-                               ngeneric.AppendChild (nparam);
+                               AttributeData.OutputAttributes (writer, gp);
 
                                var constraints = gp.Constraints;
-                               if (constraints.Count == 0)
+                               if (constraints.Count == 0) {
+                                       writer.WriteEndElement (); // generic-parameter
                                        continue;
+                               }
 
-                               XmlElement nconstraint = document.CreateElement ("generic-parameter-constraints");
+                               writer.WriteStartElement ("generic-parameter-constraints");
 
                                foreach (TypeReference constraint in constraints) {
-                                       XmlElement ncons = document.CreateElement ("generic-parameter-constraint");
-                                       ncons.SetAttribute ("name", Utils.CleanupTypeName (constraint));
-                                       nconstraint.AppendChild (ncons);
+                                       writer.WriteStartElement ("generic-parameter-constraint");
+                                       writer.WriteAttributeString ("name", Utils.CleanupTypeName (constraint));
+                                       writer.WriteEndElement (); // generic-parameter-constraint
                                }
 
-                               nparam.AppendChild (nconstraint);
+                               writer.WriteEndElement (); // generic-parameter-constraints
+
+                               writer.WriteEndElement (); // generic-parameter
                        }
+
+                       writer.WriteEndElement (); // generic-parameters
                }
        }
 
@@ -416,112 +432,107 @@ namespace CorCompare
        {
                TypeDefinition type;
 
-               public TypeData (XmlDocument document, XmlNode parent, TypeDefinition type)
-                       : base (document, parent, null)
+               public TypeData (XmlWriter writer, TypeDefinition type)
+                       : base (writer, null)
                {
                        this.type = type;
                }
                public override void DoOutput ()
                {
-                       if (document == null)
+                       if (writer == null)
                                throw new InvalidOperationException ("Document not set");
 
-                       XmlNode nclass = document.CreateElement ("class", null);
-                       AddAttribute (nclass, "name", type.Name);
+                       writer.WriteStartElement ("class");
+                       AddAttribute ("name", type.Name);
                        string classType = GetClassType (type);
-                       AddAttribute (nclass, "type", classType);
+                       AddAttribute ("type", classType);
 
                        if (type.BaseType != null)
-                               AddAttribute (nclass, "base", Utils.CleanupTypeName (type.BaseType));
+                               AddAttribute ("base", Utils.CleanupTypeName (type.BaseType));
 
                        if (type.IsSealed)
-                               AddAttribute (nclass, "sealed", "true");
+                               AddAttribute ("sealed", "true");
 
                        if (type.IsAbstract)
-                               AddAttribute (nclass, "abstract", "true");
+                               AddAttribute ("abstract", "true");
 
                        if ( (type.Attributes & TypeAttributes.Serializable) != 0 || type.IsEnum)
-                               AddAttribute (nclass, "serializable", "true");
+                               AddAttribute ("serializable", "true");
 
                        string charSet = GetCharSet (type);
-                       AddAttribute (nclass, "charset", charSet);
+                       AddAttribute ("charset", charSet);
 
                        string layout = GetLayout (type);
                        if (layout != null)
-                               AddAttribute (nclass, "layout", layout);
+                               AddAttribute ("layout", layout);
 
                        if (type.PackingSize >= 0) {
-                               AddAttribute (nclass, "pack", type.PackingSize.ToString ());
+                               AddAttribute ("pack", type.PackingSize.ToString ());
                        }
 
                        if (type.ClassSize >= 0) {
-                               AddAttribute (nclass, "size", type.ClassSize.ToString ());
+                               AddAttribute ("size", type.ClassSize.ToString ());
                        }
 
-                       parent.AppendChild (nclass);
+                       if (type.IsEnum) {
+                               var value_type = GetEnumValueField (type);
+                               if (value_type == null)
+                                       throw new NotSupportedException ();
 
-                       AttributeData.OutputAttributes (document, nclass, type);
+                               AddAttribute ("enumtype", Utils.CleanupTypeName (value_type.FieldType));
+                       }
 
-                       XmlNode ifaces = null;
+                       AttributeData.OutputAttributes (writer, type);
 
-                       foreach (TypeReference iface in TypeHelper.GetInterfaces (type).OrderBy (s => s.FullName)) {
-                               if (!TypeHelper.IsPublic (iface))
-                                       // we're only interested in public interfaces
-                                       continue;
+                       var ifaces =  TypeHelper.GetInterfaces (type).
+                               Where ((iface) => TypeHelper.IsPublic (iface)). // we're only interested in public interfaces
+                               OrderBy (s => s.FullName);
 
-                               if (ifaces == null) {
-                                       ifaces = document.CreateElement ("interfaces", null);
-                                       nclass.AppendChild (ifaces);
+                       if (ifaces.Any ()) {
+                               writer.WriteStartElement ("interfaces");
+                               foreach (TypeReference iface in ifaces) {
+                                       writer.WriteStartElement ("interface");
+                                       AddAttribute ("name", Utils.CleanupTypeName (iface));
+                                       writer.WriteEndElement (); // interface
                                }
-
-                               XmlNode iface_node = document.CreateElement ("interface", null);
-                               AddAttribute (iface_node, "name", Utils.CleanupTypeName (iface));
-                               ifaces.AppendChild (iface_node);
+                               writer.WriteEndElement (); // interfaces
                        }
 
-                       MemberData.OutputGenericParameters (document, nclass, type);
+                       MemberData.OutputGenericParameters (writer, type);
 
                        ArrayList members = new ArrayList ();
 
                        FieldDefinition [] fields = GetFields (type);
                        if (fields.Length > 0) {
                                Array.Sort (fields, MemberReferenceComparer.Default);
-                               FieldData fd = new FieldData (document, nclass, fields);
+                               FieldData fd = new FieldData (writer, fields);
                                members.Add (fd);
                        }
 
-                       if (type.IsEnum) {
-                               var value_type = GetEnumValueField (type);
-                               if (value_type == null)
-                                       throw new NotSupportedException ();
-
-                               AddAttribute (nclass, "enumtype", Utils.CleanupTypeName (value_type.FieldType));
-                       }
-
                        if (!Driver.AbiMode) {
 
                                MethodDefinition [] ctors = GetConstructors (type);
                                if (ctors.Length > 0) {
                                        Array.Sort (ctors, MethodDefinitionComparer.Default);
-                                       members.Add (new ConstructorData (document, nclass, ctors));
+                                       members.Add (new ConstructorData (writer, ctors));
                                }
 
                                PropertyDefinition[] properties = GetProperties (type);
                                if (properties.Length > 0) {
                                        Array.Sort (properties, PropertyDefinitionComparer.Default);
-                                       members.Add (new PropertyData (document, nclass, properties));
+                                       members.Add (new PropertyData (writer, properties));
                                }
 
                                EventDefinition [] events = GetEvents (type);
                                if (events.Length > 0) {
                                        Array.Sort (events, MemberReferenceComparer.Default);
-                                       members.Add (new EventData (document, nclass, events));
+                                       members.Add (new EventData (writer, events));
                                }
 
                                MethodDefinition [] methods = GetMethods (type);
                                if (methods.Length > 0) {
                                        Array.Sort (methods, MethodDefinitionComparer.Default);
-                                       members.Add (new MethodData (document, nclass, methods));
+                                       members.Add (new MethodData (writer, methods));
                                }
                        }
 
@@ -547,13 +558,15 @@ namespace CorCompare
                                var nestedArray = nested.ToArray ();
                                Array.Sort (nestedArray, TypeReferenceComparer.Default);
 
-                               XmlNode classes = document.CreateElement ("classes", null);
-                               nclass.AppendChild (classes);
+                               writer.WriteStartElement ("classes");
                                foreach (TypeDefinition t in nestedArray) {
-                                       TypeData td = new TypeData (document, classes, t);
+                                       TypeData td = new TypeData (writer, t);
                                        td.DoOutput ();
                                }
+                               writer.WriteEndElement (); // classes
                        }
+
+                       writer.WriteEndElement (); // class
                }
 
                static FieldReference GetEnumValueField (TypeDefinition type)
@@ -758,8 +771,8 @@ namespace CorCompare
 
        class FieldData : MemberData
        {
-               public FieldData (XmlDocument document, XmlNode parent, FieldDefinition [] members)
-                       : base (document, parent, members)
+               public FieldData (XmlWriter writer, FieldDefinition [] members)
+                       : base (writer, members)
                {
                }
 
@@ -775,11 +788,12 @@ namespace CorCompare
                        return ((int) field.Attributes).ToString (CultureInfo.InvariantCulture);
                }
 
-               protected override void AddExtraData (XmlNode p, MemberReference memberDefenition)
+               protected override void AddExtraAttributes (MemberReference memberDefinition)
                {
-                       base.AddExtraData (p, memberDefenition);
-                       FieldDefinition field = (FieldDefinition) memberDefenition;
-                       AddAttribute (p, "fieldtype", Utils.CleanupTypeName (field.FieldType));
+                       base.AddExtraAttributes (memberDefinition);
+
+                       FieldDefinition field = (FieldDefinition) memberDefinition;
+                       AddAttribute ("fieldtype", Utils.CleanupTypeName (field.FieldType));
 
                        if (field.IsLiteral) {
                                object value = field.Constant;//object value = field.GetValue (null);
@@ -791,11 +805,11 @@ namespace CorCompare
                                //    stringValue = ((Enum) value).ToString ("D", CultureInfo.InvariantCulture);
                                //}
                                //else {
-                                       stringValue = Convert.ToString (value, CultureInfo.InvariantCulture);
+                               stringValue = Convert.ToString (value, CultureInfo.InvariantCulture);
                                //}
 
                                if (stringValue != null)
-                                       AddAttribute (p, "value", stringValue);
+                                       AddAttribute ("value", stringValue);
                        }
                }
 
@@ -810,8 +824,8 @@ namespace CorCompare
 
        class PropertyData : MemberData
        {
-               public PropertyData (XmlDocument document, XmlNode parent, PropertyDefinition [] members)
-                       : base (document, parent, members)
+               public PropertyData (XmlWriter writer, PropertyDefinition [] members)
+                       : base (writer, members)
                {
                }
 
@@ -821,15 +835,13 @@ namespace CorCompare
                        return prop.Name;
                }
 
-               protected override void AddExtraData (XmlNode p, MemberReference memberDefenition)
+               MethodDefinition [] GetMethods (PropertyDefinition prop, out bool haveParameters)
                {
-                       base.AddExtraData (p, memberDefenition);
-                       PropertyDefinition prop = (PropertyDefinition) memberDefenition;
-                       AddAttribute (p, "ptype", Utils.CleanupTypeName (prop.PropertyType));
                        MethodDefinition _get = prop.GetMethod;
                        MethodDefinition _set = prop.SetMethod;
                        bool haveGet = (_get != null && TypeData.MustDocumentMethod(_get));
                        bool haveSet = (_set != null && TypeData.MustDocumentMethod(_set));
+                       haveParameters = haveGet || (haveSet && _set.Parameters.Count > 1);
                        MethodDefinition [] methods;
 
                        if (haveGet && haveSet) {
@@ -840,16 +852,41 @@ namespace CorCompare
                                methods = new MethodDefinition [] { _set };
                        } else {
                                //odd
-                               return;
+                               return null;
                        }
 
-                       if (haveGet || _set.Parameters.Count > 1) {
+                       return methods;
+               }
+
+               protected override void AddExtraAttributes (MemberReference memberDefinition)
+               {
+                       base.AddExtraAttributes (memberDefinition);
+
+                       PropertyDefinition prop = (PropertyDefinition) memberDefinition;
+                       AddAttribute ("ptype", Utils.CleanupTypeName (prop.PropertyType));
+
+                       bool haveParameters;
+                       MethodDefinition [] methods = GetMethods ((PropertyDefinition) memberDefinition, out haveParameters);
+
+                       if (methods != null && haveParameters) {
                                string parms = Parameters.GetSignature (methods [0].Parameters);
                                if (!string.IsNullOrEmpty (parms))
-                                       AddAttribute (p, "params", parms);
+                                       AddAttribute ("params", parms);
                        }
 
-                       MethodData data = new MethodData (document, p, methods);
+               }
+
+               protected override void AddExtraData (MemberReference memberDefenition)
+               {
+                       base.AddExtraData (memberDefenition);
+
+                       bool haveParameters;
+                       MethodDefinition [] methods = GetMethods ((PropertyDefinition) memberDefenition, out haveParameters);
+
+                       if (methods == null)
+                               return;
+                       
+                       MethodData data = new MethodData (writer, methods);
                        //data.NoMemberAttributes = true;
                        data.DoOutput ();
                }
@@ -871,8 +908,8 @@ namespace CorCompare
 
        class EventData : MemberData
        {
-               public EventData (XmlDocument document, XmlNode parent, EventDefinition [] members)
-                       : base (document, parent, members)
+               public EventData (XmlWriter writer, EventDefinition [] members)
+                       : base (writer, members)
                {
                }
 
@@ -888,11 +925,12 @@ namespace CorCompare
                        return ((int) evt.Attributes).ToString (CultureInfo.InvariantCulture);
                }
 
-               protected override void AddExtraData (XmlNode p, MemberReference memberDefenition)
+               protected override void AddExtraAttributes (MemberReference memberDefinition)
                {
-                       base.AddExtraData (p, memberDefenition);
-                       EventDefinition evt = (EventDefinition) memberDefenition;
-                       AddAttribute (p, "eventtype", Utils.CleanupTypeName (evt.EventType));
+                       base.AddExtraAttributes (memberDefinition);
+
+                       EventDefinition evt = (EventDefinition) memberDefinition;
+                       AddAttribute ("eventtype", Utils.CleanupTypeName (evt.EventType));
                }
 
                public override string ParentTag {
@@ -908,8 +946,8 @@ namespace CorCompare
        {
                bool noAtts;
 
-               public MethodData (XmlDocument document, XmlNode parent, MethodDefinition [] members)
-                       : base (document, parent, members)
+               public MethodData (XmlWriter writer, MethodDefinition [] members)
+                       : base (writer, members)
                {
                }
 
@@ -928,34 +966,50 @@ namespace CorCompare
                        return ((int)( method.Attributes)).ToString (CultureInfo.InvariantCulture);
                }
 
-               protected override void AddExtraData (XmlNode p, MemberReference memberDefenition)
+               protected override ICustomAttributeProvider GetAdditionalCustomAttributeProvider (MemberReference member)
                {
-                       base.AddExtraData (p, memberDefenition);
+                       var mbase = (MethodDefinition) member;
+                       return mbase.MethodReturnType;
+               }
 
-                       if (!(memberDefenition is MethodDefinition))
-                               return;
+               protected override void AddExtraAttributes (MemberReference memberDefinition)
+               {
+                       base.AddExtraAttributes (memberDefinition);
 
-                       MethodDefinition mbase = (MethodDefinition) memberDefenition;
+                       if (!(memberDefinition is MethodDefinition))
+                               return;
 
-                       ParameterData parms = new ParameterData (document, p, mbase.Parameters);
-                       parms.DoOutput ();
+                       MethodDefinition mbase = (MethodDefinition) memberDefinition;
 
                        if (mbase.IsAbstract)
-                               AddAttribute (p, "abstract", "true");
+                               AddAttribute ("abstract", "true");
                        if (mbase.IsVirtual)
-                               AddAttribute (p, "virtual", "true");
+                               AddAttribute ("virtual", "true");
                        if (mbase.IsFinal && mbase.IsVirtual && mbase.IsReuseSlot)
-                               AddAttribute (p, "sealed", "true");
+                               AddAttribute ("sealed", "true");
                        if (mbase.IsStatic)
-                               AddAttribute (p, "static", "true");
-
+                               AddAttribute ("static", "true");
                        string rettype = Utils.CleanupTypeName (mbase.MethodReturnType.ReturnType);
                        if (rettype != "System.Void" || !mbase.IsConstructor)
-                               AddAttribute (p, "returntype", (rettype));
+                               AddAttribute ("returntype", (rettype));
+//
+//                     if (mbase.MethodReturnType.HasCustomAttributes)
+//                             AttributeData.OutputAttributes (writer, mbase.MethodReturnType);
+               }
+
+               protected override void AddExtraData (MemberReference memberDefenition)
+               {
+                       base.AddExtraData (memberDefenition);
 
-                       AttributeData.OutputAttributes (document, p, mbase.MethodReturnType);
+                       if (!(memberDefenition is MethodDefinition))
+                               return;
 
-                       MemberData.OutputGenericParameters (document, p, mbase);
+                       MethodDefinition mbase = (MethodDefinition) memberDefenition;
+
+                       ParameterData parms = new ParameterData (writer, mbase.Parameters);
+                       parms.DoOutput ();
+
+                       MemberData.OutputGenericParameters (writer, mbase);
                }
 
                public override bool NoMemberAttributes {
@@ -974,8 +1028,8 @@ namespace CorCompare
 
        class ConstructorData : MethodData
        {
-               public ConstructorData (XmlDocument document, XmlNode parent, MethodDefinition [] members)
-                       : base (document, parent, members)
+               public ConstructorData (XmlWriter writer, MethodDefinition [] members)
+                       : base (writer, members)
                {
                }
 
@@ -992,23 +1046,20 @@ namespace CorCompare
        {
                private IList<ParameterDefinition> parameters;
 
-               public ParameterData (XmlDocument document, XmlNode parent, IList<ParameterDefinition> parameters)
-                       : base (document, parent)
+               public ParameterData (XmlWriter writer, IList<ParameterDefinition> parameters)
+                       : base (writer)
                {
                        this.parameters = parameters;
                }
 
                public override void DoOutput ()
                {
-                       XmlNode parametersNode = document.CreateElement ("parameters");
-                       parent.AppendChild (parametersNode);
-
+                       writer.WriteStartElement ("parameters");
                        foreach (ParameterDefinition parameter in parameters) {
-                               XmlNode paramNode = document.CreateElement ("parameter");
-                               parametersNode.AppendChild (paramNode);
-                               AddAttribute (paramNode, "name", parameter.Name);
-                               AddAttribute (paramNode, "position", parameter.Method.Parameters.IndexOf(parameter).ToString(CultureInfo.InvariantCulture));
-                               AddAttribute (paramNode, "attrib", ((int) parameter.Attributes).ToString());
+                               writer.WriteStartElement ("parameter");
+                               AddAttribute ("name", parameter.Name);
+                               AddAttribute ("position", parameter.Method.Parameters.IndexOf(parameter).ToString(CultureInfo.InvariantCulture));
+                               AddAttribute ("attrib", ((int) parameter.Attributes).ToString());
 
                                string direction = "in";
 
@@ -1016,84 +1067,96 @@ namespace CorCompare
                                        direction = parameter.IsOut ? "out" : "ref";
 
                                TypeReference t = parameter.ParameterType;
-                               AddAttribute (paramNode, "type", Utils.CleanupTypeName (t));
+                               AddAttribute ("type", Utils.CleanupTypeName (t));
 
                                if (parameter.IsOptional) {
-                                       AddAttribute (paramNode, "optional", "true");
+                                       AddAttribute ("optional", "true");
                                        if (parameter.HasConstant)
-                                               AddAttribute (paramNode, "defaultValue", parameter.Constant == null ? "NULL" : parameter.Constant.ToString ());
+                                               AddAttribute ("defaultValue", parameter.Constant == null ? "NULL" : parameter.Constant.ToString ());
                                }
 
                                if (direction != "in")
-                                       AddAttribute (paramNode, "direction", direction);
+                                       AddAttribute ("direction", direction);
 
-                               AttributeData.OutputAttributes (document, paramNode, parameter);
+                               AttributeData.OutputAttributes (writer, parameter);
+                               writer.WriteEndElement (); // parameter
                        }
+                       writer.WriteEndElement (); // parameters
                }
        }
 
        class AttributeData : BaseData
        {
-               IList<CustomAttribute> atts;
+               IList<ICustomAttributeProvider> providers;
 
-               AttributeData (XmlDocument doc, XmlNode parent, IList<CustomAttribute> attributes)
-                       : base (doc, parent)
+               AttributeData (XmlWriter writer, IList<ICustomAttributeProvider> providers)
+                       : base (writer)
                {
-                       atts = attributes;
+                       this.providers = providers;
                }
 
                public override void DoOutput ()
                {
-                       if (document == null)
+                       if (writer == null)
                                throw new InvalidOperationException ("Document not set");
 
-                       if (atts == null || atts.Count == 0)
+                       if (providers == null || providers.Count == 0)
+                               return;
+               
+                       if (!providers.Any ((provider) => provider != null && provider.HasCustomAttributes))
                                return;
 
-                       XmlNode natts = parent.SelectSingleNode("attributes");
-                       if (natts == null) {
-                               natts = document.CreateElement ("attributes", null);
-                               parent.AppendChild (natts);
-                       }
+                       writer.WriteStartElement ("attributes");
 
-                       foreach (var att in atts.OrderBy ((a) => a.Constructor.DeclaringType.FullName)) {
-                               string attName = Utils.CleanupTypeName (att.Constructor.DeclaringType);
-                               if (SkipAttribute (att))
+                       foreach (var provider in providers) {
+                               if (provider == null)
+                                       continue;
+                               
+                               if (!provider.HasCustomAttributes)
                                        continue;
 
-                               XmlNode node = document.CreateElement ("attribute");
-                               AddAttribute (node, "name", attName);
-
-                               XmlNode properties = null;
 
-                               Dictionary<string, object> attribute_mapping = CreateAttributeMapping (att);
+                               var ass = provider as AssemblyDefinition;
+                               if (ass != null && !Driver.FollowForwarders)
+                                       TypeForwardedToData.OutputForwarders (writer, ass);
 
-                               foreach (string name in attribute_mapping.Keys) {
-                                       if (name == "TypeId")
+                               foreach (var att in provider.CustomAttributes.OrderBy ((a) => a.Constructor.DeclaringType.FullName)) {
+                                       string attName = Utils.CleanupTypeName (att.Constructor.DeclaringType);
+                                       if (SkipAttribute (att))
                                                continue;
 
-                                       if (properties == null) {
-                                               properties = node.AppendChild (document.CreateElement ("properties"));
-                                       }
+                                       writer.WriteStartElement ("attribute");
+                                       AddAttribute ("name", attName);
 
-                                       object o = attribute_mapping [name];
+                                       var attribute_mapping = CreateAttributeMapping (att).Where ((kvp) => kvp.Key != "TypeId");
 
-                                       XmlNode n = properties.AppendChild (document.CreateElement ("property"));
-                                       AddAttribute (n, "name", name);
+                                       if (attribute_mapping.Any ()) {
+                                               writer.WriteStartElement ("properties");
+                                               foreach (var kvp in attribute_mapping) {
+                                                       string name = kvp.Key;
+                                                       object o = kvp.Value;
 
-                                       if (o == null) {
-                                               AddAttribute (n, "value", "null");
-                                               continue;
+                                                       writer.WriteStartElement ("property");
+                                                       AddAttribute ("name", name);
+
+                                                       if (o == null) {
+                                                               AddAttribute ("value", "null");
+                                                       } else {
+                                                               string value = o.ToString ();
+                                                               if (attName.EndsWith ("GuidAttribute"))
+                                                                       value = value.ToUpper ();
+                                                               AddAttribute ("value", value);
+                                                       }
+
+                                                       writer.WriteEndElement (); // property
+                                               }
+                                               writer.WriteEndElement (); // properties
                                        }
-                                       
-                                       string value = o.ToString ();
-                                       if (attName.EndsWith ("GuidAttribute"))
-                                               value = value.ToUpper ();
-                                       AddAttribute (n, "value", value);
+                                       writer.WriteEndElement (); // attribute
                                }
-
-                               natts.AppendChild (node);
                        }
+
+                       writer.WriteEndElement (); // attributes
                }
 
                static Dictionary<string, object> CreateAttributeMapping (CustomAttribute attribute)
@@ -1348,12 +1411,9 @@ namespace CorCompare
                                || type_name.EndsWith ("TODOAttribute");
                }
 
-               public static void OutputAttributes (XmlDocument doc, XmlNode parent, ICustomAttributeProvider provider)
+               public static void OutputAttributes (XmlWriter writer, params ICustomAttributeProvider[] providers)
                {
-                       if (!provider.HasCustomAttributes)
-                               return;
-                       
-                       AttributeData ad = new AttributeData (doc, parent, provider.CustomAttributes);
+                       AttributeData ad = new AttributeData (writer, providers);
                        ad.DoOutput ();
                }
        }