Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/Reflection/EnumDescriptor.cs

+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+#endregion
+
+using System;
+using System.Collections.Generic;
+
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Descriptor for an enum type in a .proto file.
+    /// </summary>
+    public sealed class EnumDescriptor : DescriptorBase
+    {
+        private readonly EnumDescriptorProto proto;
+        private readonly MessageDescriptor containingType;
+        private readonly IList<EnumValueDescriptor> values;
+        private readonly Type clrType;
+
+        internal EnumDescriptor(EnumDescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int index, Type clrType)
+            : base(file, file.ComputeFullName(parent, proto.Name), index)
+        {
+            this.proto = proto;
+            this.clrType = clrType;
+            containingType = parent;
+
+            if (proto.Value.Count == 0)
+            {
+                // We cannot allow enums with no values because this would mean there
+                // would be no valid default value for fields of this type.
+                throw new DescriptorValidationException(this, "Enums must contain at least one value.");
+            }
+
+            values = DescriptorUtil.ConvertAndMakeReadOnly(proto.Value,
+                                                           (value, i) => new EnumValueDescriptor(value, file, this, i));
+
+            File.DescriptorPool.AddSymbol(this);
+        }
+
+        internal EnumDescriptorProto Proto { get { return proto; } }
+
+        /// <summary>
+        /// The brief name of the descriptor's target.
+        /// </summary>
+        public override string Name { get { return proto.Name; } }
+
+        /// <summary>
+        /// The CLR type for this enum. For generated code, this will be a CLR enum type.
+        /// </summary>
+        public Type ClrType { get { return clrType; } }
+
+        /// <value>
+        /// If this is a nested type, get the outer descriptor, otherwise null.
+        /// </value>
+        public MessageDescriptor ContainingType
+        {
+            get { return containingType; }
+        }
+
+        /// <value>
+        /// An unmodifiable list of defined value descriptors for this enum.
+        /// </value>
+        public IList<EnumValueDescriptor> Values
+        {
+            get { return values; }
+        }
+
+        /// <summary>
+        /// Finds an enum value by number. If multiple enum values have the
+        /// same number, this returns the first defined value with that number.
+        /// If there is no value for the given number, this returns <c>null</c>.
+        /// </summary>
+        public EnumValueDescriptor FindValueByNumber(int number)
+        {
+            return File.DescriptorPool.FindEnumValueByNumber(this, number);
+        }
+
+        /// <summary>
+        /// Finds an enum value by name.
+        /// </summary>
+        /// <param name="name">The unqualified name of the value (e.g. "FOO").</param>
+        /// <returns>The value's descriptor, or null if not found.</returns>
+        public EnumValueDescriptor FindValueByName(string name)
+        {
+            return File.DescriptorPool.FindSymbol<EnumValueDescriptor>(FullName + "." + name);
+        }
+    }
+}