1 files changed, 55 insertions, 0 deletions
diff --git a/csharp/ProtocolBuffers/Descriptors/MethodDescriptor.cs b/csharp/ProtocolBuffers/Descriptors/MethodDescriptor.cs
new file mode 100644
index 00000000..efc3fa4c
--- /dev/null
+++ b/csharp/ProtocolBuffers/Descriptors/MethodDescriptor.cs
@@ -0,0 +1,55 @@
+using Google.ProtocolBuffers.DescriptorProtos;
+
+namespace Google.ProtocolBuffers.Descriptors {
+  /// <summary>
+  /// Describes a single method in a service.
+  /// </summary>
+  public class MethodDescriptor : IndexedDescriptorBase<MethodDescriptorProto, MethodOptions> {
+
+    private readonly ServiceDescriptor service;
+    private MessageDescriptor inputType;
+    private MessageDescriptor outputType;
+
+    /// <value>
+    /// The service this method belongs to.
+    /// </value>
+    public ServiceDescriptor Service {
+      get { return service; }
+    }
+
+    /// <value>
+    /// The method's input type.
+    /// </value>
+    public MessageDescriptor InputType {
+      get { return inputType; }
+    }
+
+    /// <value>
+    /// The method's input type.
+    /// </value>
+    public MessageDescriptor OutputType {
+      get { return inputType; }
+    }
+
+    internal MethodDescriptor(MethodDescriptorProto proto, FileDescriptor file,
+        ServiceDescriptor parent, int index) 
+        : base(proto, file, parent.FullName + "." + proto.Name, index) {
+      service = parent;
+      file.DescriptorPool.AddSymbol(this);
+    }
+
+    internal void CrossLink() {
+      IDescriptor lookup = File.DescriptorPool.LookupSymbol(Proto.InputType, this);
+      if (!(lookup is MessageDescriptor)) {
+        throw new DescriptorValidationException(this, "\"" + Proto.InputType + "\" is not a message type.");
+      }
+      inputType = (MessageDescriptor) lookup;
+
+      lookup = File.DescriptorPool.LookupSymbol(Proto.OutputType, this);
+      if (!(lookup is MessageDescriptor)) {
+        throw new DescriptorValidationException(this, "\"" + Proto.OutputType + "\" is not a message type.");
+      }
+      outputType = (MessageDescriptor) lookup;
+    }
+  }
+}