1 files changed, 34 insertions, 0 deletions
diff --git a/csharp/ProtocolBuffers/GeneratedExtension.cs b/csharp/ProtocolBuffers/GeneratedExtension.cs
new file mode 100644
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+++ b/csharp/ProtocolBuffers/GeneratedExtension.cs
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+using System;
+using System.Collections.Generic;
+using System.Text;
+using Google.ProtocolBuffers.Descriptors;
+
+namespace Google.ProtocolBuffers {
+
+  /// <summary>
+  /// Base class for all generated extensions.
+  /// </summary>
+  /// <remarks>
+  /// The protocol compiler generates a static singleton instance of this
+  /// class for each extension. For exmaple, imagine a .proto file with:
+  /// <code>
+  /// message Foo {
+  ///   extensions 1000 to max
+  /// }
+  /// 
+  /// extend Foo {
+  ///   optional int32 bar;
+  /// }
+  /// </code>
+  /// Then MyProto.Foo.Bar has type GeneratedExtension&lt;MyProto.Foo,int&gt;.
+  /// <para />
+  /// In general, users should ignore the details of this type, and
+  /// simply use the static singletons as parmaeters to the extension accessors
+  /// in ExtendableMessage and ExtendableBuilder.
+  /// </remarks>
+  public class GeneratedExtension<TContainer, TExtension> where TContainer : IMessage<TContainer> {
+    public FieldDescriptor Descriptor;
+
+    public IMessage MessageDefaultInstance;
+  }
+}