1 files changed, 97 insertions, 11 deletions

diff --git a/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs b/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
index fd8c6e5b..548f226b 100644
--- a/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
+++ b/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
@@ -1,27 +1,113 @@
-
-using System.Collections.Generic;
+using System.Collections.Generic;
 using Google.ProtocolBuffers.DescriptorProtos;
 
 namespace Google.ProtocolBuffers.Descriptors {
-  public class MessageDescriptor : DescriptorBase<DescriptorProto, MessageOptions> {
-    public IList<FieldDescriptor> Fields;
 
-    internal MessageDescriptor(DescriptorProto proto, FileDescriptor file) : base(proto, file) {
+  /// <summary>
+  /// Describes a message type.
+  /// </summary>
+  public class MessageDescriptor : IndexedDescriptorBase<DescriptorProto, MessageOptions> {
+
+    private readonly MessageDescriptor containingType;
+    private readonly IList<MessageDescriptor> nestedTypes;
+    private readonly IList<EnumDescriptor> enumTypes;
+    private readonly IList<FieldDescriptor> fields;
+    private readonly IList<FieldDescriptor> extensions;
+
+    internal MessageDescriptor(DescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int typeIndex)
+        : base(proto, file, ComputeFullName(file, parent, proto.Name), typeIndex) {
+      containingType = parent;
+
+      nestedTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.NestedTypeList,
+          (type, index) => new MessageDescriptor(type, file, null, index));
+
+      enumTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.EnumTypeList,
+          (type, index) => new EnumDescriptor(type, file, null, index));
+
+      fields = DescriptorUtil.ConvertAndMakeReadOnly(proto.FieldList,
+          (field, index) => new FieldDescriptor(field, file, null, index, false));
+
+      extensions = DescriptorUtil.ConvertAndMakeReadOnly(proto.ExtensionList,
+          (field, index) => new FieldDescriptor(field, file, null, index, true));
+
+      file.DescriptorPool.AddSymbol(this);
     }
 
-    internal bool IsExtensionNumber(int fieldNumber) {
-      throw new System.NotImplementedException();
+    /// <value>
+    /// An unmodifiable list of this message type's fields.
+    /// </value>
+    public IList<FieldDescriptor> Fields {
+      get { return fields; }
     }
 
-    internal FieldDescriptor FindFieldByNumber(int fieldNumber) {
-      throw new System.NotImplementedException();
+    /// <value>
+    /// An unmodifiable list of this message type's extensions.
+    /// </value>
+    public IList<FieldDescriptor> Extensions {
+      get { return extensions; }
     }
 
     /// <value>
-    /// List of message types nested within this one.
+    /// An unmodifiable list of this message type's nested types.
     /// </value>
     public IList<MessageDescriptor> NestedTypes {
-      get { throw new System.NotImplementedException(); }
+      get { return nestedTypes; }
+    }
+
+    /// <value>
+    /// An unmodifiable list of this message type's enum types.
+    /// </value>
+    public IList<EnumDescriptor> EnumTypes {
+      get { return enumTypes; }
+    }
+
+    /// <summary>
+    /// Determines if the given field number is an extension.
+    /// </summary>
+    public bool IsExtensionNumber(int number) {
+      foreach (DescriptorProto.Types.ExtensionRange range in Proto.ExtensionRangeList) {
+        if (range.Start <= number && number < range.End) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    /// <summary>
+    /// Finds a field by field number.
+    /// </summary>
+    /// <param name="number">The field number within this message type.</param>
+    /// <returns>The field's descriptor, or null if not found.</returns>
+    public FieldDescriptor FindFieldByNumber(int number) {
+      return File.DescriptorPool.FindFieldByNumber(this, number);
+    }
+
+    /// <summary>
+    /// Finds a nested descriptor by name. The is valid for fields, nested
+    /// message types and enums.
+    /// </summary>
+    /// <param name="name">The unqualified name of the descriptor, e.g. "Foo"</param>
+    /// <returns>The descriptor, or null if not found.</returns>
+    public T FindDescriptor<T>(string name) 
+        where T : class, IDescriptor {
+      return File.DescriptorPool.FindSymbol<T>(FullName + "." + name);
+    }
+
+    /// <summary>
+    /// Looks up and cross-links all fields, nested types, and extensions.
+    /// </summary>
+    internal void CrossLink() {
+      foreach (MessageDescriptor message in nestedTypes) {
+        message.CrossLink();
+      }
+
+      foreach (FieldDescriptor field in fields) {
+        field.CrossLink();
+      }
+
+      foreach (FieldDescriptor extension in extensions) {
+        extension.CrossLink();
+      }
     }
   }
 }