Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.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;
+using System.Collections.ObjectModel;
+using System.Linq;
+
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Describes a message type.
+    /// </summary>
+    public sealed class MessageDescriptor : DescriptorBase
+    {
+        private static readonly HashSet<string> WellKnownTypeNames = new HashSet<string>
+        {
+            "google/protobuf/any.proto",
+            "google/protobuf/api.proto",
+            "google/protobuf/duration.proto",
+            "google/protobuf/empty.proto",
+            "google/protobuf/wrappers.proto",
+            "google/protobuf/timestamp.proto",
+            "google/protobuf/field_mask.proto",
+            "google/protobuf/source_context.proto",
+            "google/protobuf/struct.proto",
+            "google/protobuf/type.proto",
+        };
+
+        private readonly IList<FieldDescriptor> fieldsInDeclarationOrder;
+        private readonly IList<FieldDescriptor> fieldsInNumberOrder;
+        private readonly IDictionary<string, FieldDescriptor> jsonFieldMap;
+        
+        internal MessageDescriptor(DescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int typeIndex, GeneratedCodeInfo generatedCodeInfo)
+            : base(file, file.ComputeFullName(parent, proto.Name), typeIndex)
+        {
+            Proto = proto;
+            Parser = generatedCodeInfo?.Parser;
+            ClrType = generatedCodeInfo?.ClrType;
+            ContainingType = parent;
+
+            // Note use of generatedCodeInfo. rather than generatedCodeInfo?. here... we don't expect
+            // to see any nested oneofs, types or enums in "not actually generated" code... we do
+            // expect fields though (for map entry messages).
+            Oneofs = DescriptorUtil.ConvertAndMakeReadOnly(
+                proto.OneofDecl,
+                (oneof, index) =>
+                new OneofDescriptor(oneof, file, this, index, generatedCodeInfo.OneofNames[index]));
+
+            NestedTypes = DescriptorUtil.ConvertAndMakeReadOnly(
+                proto.NestedType,
+                (type, index) =>
+                new MessageDescriptor(type, file, this, index, generatedCodeInfo.NestedTypes[index]));
+
+            EnumTypes = DescriptorUtil.ConvertAndMakeReadOnly(
+                proto.EnumType,
+                (type, index) =>
+                new EnumDescriptor(type, file, this, index, generatedCodeInfo.NestedEnums[index]));
+
+            fieldsInDeclarationOrder = DescriptorUtil.ConvertAndMakeReadOnly(
+                proto.Field,
+                (field, index) =>
+                new FieldDescriptor(field, file, this, index, generatedCodeInfo?.PropertyNames[index]));
+            fieldsInNumberOrder = new ReadOnlyCollection<FieldDescriptor>(fieldsInDeclarationOrder.OrderBy(field => field.FieldNumber).ToArray());
+            // TODO: Use field => field.Proto.JsonName when we're confident it's appropriate. (And then use it in the formatter, too.)
+            jsonFieldMap = new ReadOnlyDictionary<string, FieldDescriptor>(fieldsInNumberOrder.ToDictionary(field => JsonFormatter.ToCamelCase(field.Name)));
+            file.DescriptorPool.AddSymbol(this);
+            Fields = new FieldCollection(this);
+        }
+
+        /// <summary>
+        /// The brief name of the descriptor's target.
+        /// </summary>
+        public override string Name => Proto.Name;
+
+        internal DescriptorProto Proto { get; }
+
+        /// <summary>
+        /// The CLR type used to represent message instances from this descriptor.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// The value returned by this property will be non-null for all regular fields. However,
+        /// if a message containing a map field is introspected, the list of nested messages will include
+        /// an auto-generated nested key/value pair message for the field. This is not represented in any
+        /// generated type, so this property will return null in such cases.
+        /// </para>
+        /// <para>
+        /// For wrapper types (<see cref="Google.Protobuf.WellKnownTypes.StringValue"/> and the like), the type returned here
+        /// will be the generated message type, not the native type used by reflection for fields of those types. Code
+        /// using reflection should call <see cref="IsWrapperType"/> to determine whether a message descriptor represents
+        /// a wrapper type, and handle the result appropriately.
+        /// </para>
+        /// </remarks>
+        public Type ClrType { get; }
+
+        /// <summary>
+        /// A parser for this message type.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// As <see cref="MessageDescriptor"/> is not generic, this cannot be statically
+        /// typed to the relevant type, but it should produce objects of a type compatible with <see cref="ClrType"/>.
+        /// </para>
+        /// <para>
+        /// The value returned by this property will be non-null for all regular fields. However,
+        /// if a message containing a map field is introspected, the list of nested messages will include
+        /// an auto-generated nested key/value pair message for the field. No message parser object is created for
+        /// such messages, so this property will return null in such cases.
+        /// </para>
+        /// <para>
+        /// For wrapper types (<see cref="Google.Protobuf.WellKnownTypes.StringValue"/> and the like), the parser returned here
+        /// will be the generated message type, not the native type used by reflection for fields of those types. Code
+        /// using reflection should call <see cref="IsWrapperType"/> to determine whether a message descriptor represents
+        /// a wrapper type, and handle the result appropriately.
+        /// </para>
+        /// </remarks>
+        public MessageParser Parser { get; }
+
+        /// <summary>
+        /// Returns whether this message is one of the "well known types" which may have runtime/protoc support.
+        /// </summary>
+        internal bool IsWellKnownType => File.Package == "google.protobuf" && WellKnownTypeNames.Contains(File.Name);
+
+        /// <summary>
+        /// Returns whether this message is one of the "wrapper types" used for fields which represent primitive values
+        /// with the addition of presence.
+        /// </summary>
+        internal bool IsWrapperType => File.Package == "google.protobuf" && File.Name == "google/protobuf/wrappers.proto";
+
+        /// <value>
+        /// If this is a nested type, get the outer descriptor, otherwise null.
+        /// </value>
+        public MessageDescriptor ContainingType { get; }
+
+        /// <value>
+        /// A collection of fields, which can be retrieved by name or field number.
+        /// </value>
+        public FieldCollection Fields { get; }
+
+        /// <value>
+        /// An unmodifiable list of this message type's nested types.
+        /// </value>
+        public IList<MessageDescriptor> NestedTypes { get; }
+
+        /// <value>
+        /// An unmodifiable list of this message type's enum types.
+        /// </value>
+        public IList<EnumDescriptor> EnumTypes { get; }
+
+        /// <value>
+        /// An unmodifiable list of the "oneof" field collections in this message type.
+        /// </value>
+        public IList<OneofDescriptor> Oneofs { get; }
+
+        /// <summary>
+        /// Finds a field by field name.
+        /// </summary>
+        /// <param name="name">The unqualified name of the field (e.g. "foo").</param>
+        /// <returns>The field's descriptor, or null if not found.</returns>
+        public FieldDescriptor FindFieldByName(String name) => File.DescriptorPool.FindSymbol<FieldDescriptor>(FullName + "." + name);
+
+        /// <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) => File.DescriptorPool.FindFieldByNumber(this, number);
+
+        /// <summary>
+        /// Finds a nested descriptor by name. The is valid for fields, nested
+        /// message types, oneofs 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 =>
+            File.DescriptorPool.FindSymbol<T>(FullName + "." + name);
+
+        /// <summary>
+        /// Looks up and cross-links all fields and nested types.
+        /// </summary>
+        internal void CrossLink()
+        {
+            foreach (MessageDescriptor message in NestedTypes)
+            {
+                message.CrossLink();
+            }
+
+            foreach (FieldDescriptor field in fieldsInDeclarationOrder)
+            {
+                field.CrossLink();
+            }
+
+            foreach (OneofDescriptor oneof in Oneofs)
+            {
+                oneof.CrossLink();
+            }
+        }
+
+        /// <summary>
+        /// A collection to simplify retrieving the field accessor for a particular field.
+        /// </summary>
+        public sealed class FieldCollection
+        {
+            private readonly MessageDescriptor messageDescriptor;
+
+            internal FieldCollection(MessageDescriptor messageDescriptor)
+            {
+                this.messageDescriptor = messageDescriptor;
+            }
+
+            /// <value>
+            /// Returns the fields in the message as an immutable list, in the order in which they
+            /// are declared in the source .proto file.
+            /// </value>
+            public IList<FieldDescriptor> InDeclarationOrder() => messageDescriptor.fieldsInDeclarationOrder;
+
+            /// <value>
+            /// Returns the fields in the message as an immutable list, in ascending field number
+            /// order. Field numbers need not be contiguous, so there is no direct mapping from the
+            /// index in the list to the field number; to retrieve a field by field number, it is better
+            /// to use the <see cref="FieldCollection"/> indexer.
+            /// </value>
+            public IList<FieldDescriptor> InFieldNumberOrder() => messageDescriptor.fieldsInNumberOrder;
+
+            // TODO: consider making this public in the future. (Being conservative for now...)
+
+            /// <value>
+            /// Returns a read-only dictionary mapping the field names in this message as they're used
+            /// in the JSON representation to the field descriptors. For example, a field <c>foo_bar</c>
+            /// in the message would result in an entry with a key <c>fooBar</c>.
+            /// </value>
+            internal IDictionary<string, FieldDescriptor> ByJsonName() => messageDescriptor.jsonFieldMap;
+
+            /// <summary>
+            /// Retrieves the descriptor for the field with the given number.
+            /// </summary>
+            /// <param name="number">Number of the field to retrieve the descriptor for</param>
+            /// <returns>The accessor for the given field</returns>
+            /// <exception cref="KeyNotFoundException">The message descriptor does not contain a field
+            /// with the given number</exception>
+            public FieldDescriptor this[int number]
+            {
+                get
+                {
+                    var fieldDescriptor = messageDescriptor.FindFieldByNumber(number);
+                    if (fieldDescriptor == null)
+                    {
+                        throw new KeyNotFoundException("No such field number");
+                    }
+                    return fieldDescriptor;
+                }
+            }
+
+            /// <summary>
+            /// Retrieves the descriptor for the field with the given name.
+            /// </summary>
+            /// <param name="name">Name of the field to retrieve the descriptor for</param>
+            /// <returns>The descriptor for the given field</returns>
+            /// <exception cref="KeyNotFoundException">The message descriptor does not contain a field
+            /// with the given name</exception>
+            public FieldDescriptor this[string name]
+            {
+                get
+                {
+                    var fieldDescriptor = messageDescriptor.FindFieldByName(name);
+                    if (fieldDescriptor == null)
+                    {
+                        throw new KeyNotFoundException("No such field name");
+                    }
+                    return fieldDescriptor;
+                }
+            }
+        }
+    }
+}