Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
diff --git a/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs b/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
new file mode 100644
index 0000000000000000000000000000000000000000..48ee55962015bbdc79cee2a2e4058d9684e27f14
--- /dev/null
+++ b/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs
@@ -0,0 +1,344 @@
+#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;
+
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Describes a .proto file, including everything defined within.
+    /// IDescriptor is implemented such that the File property returns this descriptor,
+    /// and the FullName is the same as the Name.
+    /// </summary>
+    public sealed class FileDescriptor : IDescriptor
+    {
+        private FileDescriptor(ByteString descriptorData, FileDescriptorProto proto, FileDescriptor[] dependencies, DescriptorPool pool, bool allowUnknownDependencies, GeneratedCodeInfo generatedCodeInfo)
+        {
+            SerializedData = descriptorData;
+            DescriptorPool = pool;
+            Proto = proto;
+            Dependencies = new ReadOnlyCollection<FileDescriptor>((FileDescriptor[]) dependencies.Clone());
+
+            PublicDependencies = DeterminePublicDependencies(this, proto, dependencies, allowUnknownDependencies);
+
+            pool.AddPackage(Package, this);
+
+            MessageTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.MessageType,
+                                                                 (message, index) =>
+                                                                 new MessageDescriptor(message, this, null, index, generatedCodeInfo.NestedTypes[index]));
+
+            EnumTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.EnumType,
+                                                              (enumType, index) =>
+                                                              new EnumDescriptor(enumType, this, null, index, generatedCodeInfo.NestedEnums[index]));
+
+            Services = DescriptorUtil.ConvertAndMakeReadOnly(proto.Service,
+                                                             (service, index) =>
+                                                             new ServiceDescriptor(service, this, index));
+        }
+
+        /// <summary>
+        /// Computes the full name of a descriptor within this file, with an optional parent message.
+        /// </summary>
+        internal string ComputeFullName(MessageDescriptor parent, string name)
+        {
+            if (parent != null)
+            {
+                return parent.FullName + "." + name;
+            }
+            if (Package.Length > 0)
+            {
+                return Package + "." + name;
+            }
+            return name;
+        }
+
+        /// <summary>
+        /// Extracts public dependencies from direct dependencies. This is a static method despite its
+        /// first parameter, as the value we're in the middle of constructing is only used for exceptions.
+        /// </summary>
+        private static IList<FileDescriptor> DeterminePublicDependencies(FileDescriptor @this, FileDescriptorProto proto, FileDescriptor[] dependencies, bool allowUnknownDependencies)
+        {
+            var nameToFileMap = new Dictionary<string, FileDescriptor>();
+            foreach (var file in dependencies)
+            {
+                nameToFileMap[file.Name] = file;
+            }
+            var publicDependencies = new List<FileDescriptor>();
+            for (int i = 0; i < proto.PublicDependency.Count; i++)
+            {
+                int index = proto.PublicDependency[i];
+                if (index < 0 || index >= proto.Dependency.Count)
+                {
+                    throw new DescriptorValidationException(@this, "Invalid public dependency index.");
+                }
+                string name = proto.Dependency[index];
+                FileDescriptor file = nameToFileMap[name];
+                if (file == null)
+                {
+                    if (!allowUnknownDependencies)
+                    {
+                        throw new DescriptorValidationException(@this, "Invalid public dependency: " + name);
+                    }
+                    // Ignore unknown dependencies.
+                }
+                else
+                {
+                    publicDependencies.Add(file);
+                }
+            }
+            return new ReadOnlyCollection<FileDescriptor>(publicDependencies);
+        }
+
+        /// <value>
+        /// The descriptor in its protocol message representation.
+        /// </value>
+        internal FileDescriptorProto Proto { get; }
+
+        /// <value>
+        /// The file name.
+        /// </value>
+        public string Name => Proto.Name;
+
+        /// <summary>
+        /// The package as declared in the .proto file. This may or may not
+        /// be equivalent to the .NET namespace of the generated classes.
+        /// </summary>
+        public string Package => Proto.Package;
+
+        /// <value>
+        /// Unmodifiable list of top-level message types declared in this file.
+        /// </value>
+        public IList<MessageDescriptor> MessageTypes { get; }
+
+        /// <value>
+        /// Unmodifiable list of top-level enum types declared in this file.
+        /// </value>
+        public IList<EnumDescriptor> EnumTypes { get; }
+
+        /// <value>
+        /// Unmodifiable list of top-level services declared in this file.
+        /// </value>
+        public IList<ServiceDescriptor> Services { get; }
+
+        /// <value>
+        /// Unmodifiable list of this file's dependencies (imports).
+        /// </value>
+        public IList<FileDescriptor> Dependencies { get; }
+
+        /// <value>
+        /// Unmodifiable list of this file's public dependencies (public imports).
+        /// </value>
+        public IList<FileDescriptor> PublicDependencies { get; }
+
+        /// <value>
+        /// The original serialized binary form of this descriptor.
+        /// </value>
+        public ByteString SerializedData { get; }
+
+        /// <value>
+        /// Implementation of IDescriptor.FullName - just returns the same as Name.
+        /// </value>
+        string IDescriptor.FullName => Name;
+
+        /// <value>
+        /// Implementation of IDescriptor.File - just returns this descriptor.
+        /// </value>
+        FileDescriptor IDescriptor.File => this;
+
+        /// <value>
+        /// Pool containing symbol descriptors.
+        /// </value>
+        internal DescriptorPool DescriptorPool { get; }
+
+        /// <summary>
+        /// Finds a type (message, enum, service or extension) in the file by name. Does not find nested types.
+        /// </summary>
+        /// <param name="name">The unqualified type name to look for.</param>
+        /// <typeparam name="T">The type of descriptor to look for</typeparam>
+        /// <returns>The type's descriptor, or null if not found.</returns>
+        public T FindTypeByName<T>(String name)
+            where T : class, IDescriptor
+        {
+            // Don't allow looking up nested types.  This will make optimization
+            // easier later.
+            if (name.IndexOf('.') != -1)
+            {
+                return null;
+            }
+            if (Package.Length > 0)
+            {
+                name = Package + "." + name;
+            }
+            T result = DescriptorPool.FindSymbol<T>(name);
+            if (result != null && result.File == this)
+            {
+                return result;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Builds a FileDescriptor from its protocol buffer representation.
+        /// </summary>
+        /// <param name="descriptorData">The original serialized descriptor data.
+        /// We have only limited proto2 support, so serializing FileDescriptorProto
+        /// would not necessarily give us this.</param>
+        /// <param name="proto">The protocol message form of the FileDescriptor.</param>
+        /// <param name="dependencies">FileDescriptors corresponding to all of the
+        /// file's dependencies, in the exact order listed in the .proto file. May be null,
+        /// in which case it is treated as an empty array.</param>
+        /// <param name="allowUnknownDependencies">Whether unknown dependencies are ignored (true) or cause an exception to be thrown (false).</param>
+        /// <param name="generatedCodeInfo">Details about generated code, for the purposes of reflection.</param>
+        /// <exception cref="DescriptorValidationException">If <paramref name="proto"/> is not
+        /// a valid descriptor. This can occur for a number of reasons, such as a field
+        /// having an undefined type or because two messages were defined with the same name.</exception>
+        private static FileDescriptor BuildFrom(ByteString descriptorData, FileDescriptorProto proto, FileDescriptor[] dependencies, bool allowUnknownDependencies, GeneratedCodeInfo generatedCodeInfo)
+        {
+            // Building descriptors involves two steps: translating and linking.
+            // In the translation step (implemented by FileDescriptor's
+            // constructor), we build an object tree mirroring the
+            // FileDescriptorProto's tree and put all of the descriptors into the
+            // DescriptorPool's lookup tables.  In the linking step, we look up all
+            // type references in the DescriptorPool, so that, for example, a
+            // FieldDescriptor for an embedded message contains a pointer directly
+            // to the Descriptor for that message's type.  We also detect undefined
+            // types in the linking step.
+            if (dependencies == null)
+            {
+                dependencies = new FileDescriptor[0];
+            }
+
+            DescriptorPool pool = new DescriptorPool(dependencies);
+            FileDescriptor result = new FileDescriptor(descriptorData, proto, dependencies, pool, allowUnknownDependencies, generatedCodeInfo);
+
+            // Validate that the dependencies we've been passed (as FileDescriptors) are actually the ones we
+            // need.
+            if (dependencies.Length != proto.Dependency.Count)
+            {
+                throw new DescriptorValidationException(
+                    result,
+                    "Dependencies passed to FileDescriptor.BuildFrom() don't match " +
+                    "those listed in the FileDescriptorProto.");
+            }
+            for (int i = 0; i < proto.Dependency.Count; i++)
+            {
+                if (dependencies[i].Name != proto.Dependency[i])
+                {
+                    throw new DescriptorValidationException(
+                        result,
+                        "Dependencies passed to FileDescriptor.BuildFrom() don't match " +
+                        "those listed in the FileDescriptorProto. Expected: " +
+                        proto.Dependency[i] + " but was: " + dependencies[i].Name);
+                }
+            }
+
+            result.CrossLink();
+            return result;
+        }
+
+        private void CrossLink()
+        {
+            foreach (MessageDescriptor message in MessageTypes)
+            {
+                message.CrossLink();
+            }
+
+            foreach (ServiceDescriptor service in Services)
+            {
+                service.CrossLink();
+            }
+        }
+
+        /// <summary>
+        /// Creates a descriptor for generated code.
+        /// </summary>
+        /// <remarks>
+        /// This method is only designed to be used by the results of generating code with protoc,
+        /// which creates the appropriate dependencies etc. It has to be public because the generated
+        /// code is "external", but should not be called directly by end users.
+        /// </remarks>
+        public static FileDescriptor FromGeneratedCode(
+            byte[] descriptorData,
+            FileDescriptor[] dependencies,
+            GeneratedCodeInfo generatedCodeInfo)
+        {
+            FileDescriptorProto proto;
+            try
+            {
+                proto = FileDescriptorProto.Parser.ParseFrom(descriptorData);
+            }
+            catch (InvalidProtocolBufferException e)
+            {
+                throw new ArgumentException("Failed to parse protocol buffer descriptor for generated code.", e);
+            }
+
+            try
+            {
+                // When building descriptors for generated code, we allow unknown
+                // dependencies by default.
+                return BuildFrom(ByteString.CopyFrom(descriptorData), proto, dependencies, true, generatedCodeInfo);
+            }
+            catch (DescriptorValidationException e)
+            {
+                throw new ArgumentException($"Invalid embedded descriptor for \"{proto.Name}\".", e);
+            }
+        }
+
+        /// <summary>
+        /// Returns a <see cref="System.String" /> that represents this instance.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="System.String" /> that represents this instance.
+        /// </returns>
+        public override string ToString()
+        {
+            return $"FileDescriptor for {Name}";
+        }
+
+        /// <summary>
+        /// Returns the file descriptor for descriptor.proto.
+        /// </summary>
+        /// <remarks>
+        /// This is used for protos which take a direct dependency on <c>descriptor.proto</c>, typically for
+        /// annotations. While <c>descriptor.proto</c> is a proto2 file, it is built into the Google.Protobuf
+        /// runtime for reflection purposes. The messages are internal to the runtime as they would require
+        /// proto2 semantics for full support, but the file descriptor is available via this property. The
+        /// C# codegen in protoc automatically uses this property when it detects a dependency on <c>descriptor.proto</c>.
+        /// </remarks>
+        /// <value>
+        /// The file descriptor for <c>descriptor.proto</c>.
+        /// </value>
+        public static FileDescriptor DescriptorProtoFileDescriptor { get { return DescriptorReflection.Descriptor; } }
+    }
+}