1 files changed, 91 insertions, 0 deletions
diff --git a/csharp/src/ProtocolBuffers/FieldAccess/OneofAccessor.cs b/csharp/src/ProtocolBuffers/FieldAccess/OneofAccessor.cs
new file mode 100644
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+++ b/csharp/src/ProtocolBuffers/FieldAccess/OneofAccessor.cs
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+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// Author: jieluo@google.com (Jie Luo)
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+using System;
+using System.Reflection;
+using Google.ProtocolBuffers.Descriptors;
+
+namespace Google.ProtocolBuffers.FieldAccess
+{
+    /// <summary>
+    /// Access for an oneof
+    /// </summary>
+    internal class OneofAccessor<TMessage, TBuilder>
+        where TMessage : IMessage<TMessage, TBuilder>
+        where TBuilder : IBuilder<TMessage, TBuilder>
+    {
+        private readonly Func<TMessage, object> caseDelegate;
+        private readonly Func<TBuilder, IBuilder> clearDelegate;
+        private MessageDescriptor descriptor;
+
+        internal OneofAccessor(MessageDescriptor descriptor, string name) 
+        {
+            this.descriptor = descriptor;
+            MethodInfo clearMethod = typeof(TBuilder).GetMethod("Clear" + name);
+            PropertyInfo caseProperty = typeof(TMessage).GetProperty(name + "Case");
+            if (clearMethod == null || caseProperty == null)
+            {
+                throw new ArgumentException("Not all required properties/methods available for oneof");
+            }
+            
+
+            clearDelegate = ReflectionUtil.CreateDelegateFunc<TBuilder, IBuilder>(clearMethod);
+            caseDelegate = ReflectionUtil.CreateUpcastDelegate<TMessage>(caseProperty.GetGetMethod());
+        }
+
+        /// <summary>
+        /// Indicates whether the specified message has set any field in the oneof.
+        /// </summary>
+        public bool Has(TMessage message)
+        {
+            return ((int) caseDelegate(message) != 0);
+        }
+
+        /// <summary>
+        /// Clears the oneof in the specified builder.
+        /// </summary>
+        public void Clear(TBuilder builder)
+        {
+            clearDelegate(builder);
+        }
+
+        /// <summary>
+        /// Indicates which field in the oneof is set for specified message
+        /// </summary>
+        public virtual FieldDescriptor GetOneofFieldDescriptor(TMessage message)
+        {
+            int fieldNumber = (int) caseDelegate(message);
+            if (fieldNumber > 0)
+            {
+                return descriptor.FindFieldByNumber(fieldNumber);
+            }
+            return null;
+        }
+    }
+}