Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.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.Linq;
+using Google.Protobuf.Compatibility;
+
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Descriptor for a field or extension within a message in a .proto file.
+    /// </summary>
+    public sealed class FieldDescriptor : DescriptorBase, IComparable<FieldDescriptor>
+    {
+        private readonly FieldDescriptorProto proto;
+        private EnumDescriptor enumType;
+        private MessageDescriptor messageType;
+        private readonly MessageDescriptor containingType;
+        private readonly OneofDescriptor containingOneof;
+        private FieldType fieldType;
+        private readonly string propertyName; // Annoyingly, needed in Crosslink.
+        private IFieldAccessor accessor;
+
+        internal FieldDescriptor(FieldDescriptorProto proto, FileDescriptor file,
+                                 MessageDescriptor parent, int index, string propertyName)
+            : base(file, file.ComputeFullName(parent, proto.Name), index)
+        {
+            this.proto = proto;
+            if (proto.Type != 0)
+            {
+                fieldType = GetFieldTypeFromProtoType(proto.Type);
+            }
+
+            if (FieldNumber <= 0)
+            {
+                throw new DescriptorValidationException(this, "Field numbers must be positive integers.");
+            }
+            containingType = parent;
+            // OneofIndex "defaults" to -1 due to a hack in FieldDescriptor.OnConstruction.
+            if (proto.OneofIndex != -1)
+            {
+                if (proto.OneofIndex < 0 || proto.OneofIndex >= parent.Proto.OneofDecl.Count)
+                {
+                    throw new DescriptorValidationException(this,
+                        $"FieldDescriptorProto.oneof_index is out of range for type {parent.Name}");
+                }
+                containingOneof = parent.Oneofs[proto.OneofIndex];
+            }
+
+            file.DescriptorPool.AddSymbol(this);
+            // We can't create the accessor until we've cross-linked, unfortunately, as we
+            // may not know whether the type of the field is a map or not. Remember the property name
+            // for later.
+            // We could trust the generated code and check whether the type of the property is
+            // a MapField, but that feels a tad nasty.
+            this.propertyName = propertyName;
+        }
+
+        /// <summary>
+        /// The brief name of the descriptor's target.
+        /// </summary>
+        public override string Name { get { return proto.Name; } }
+
+        internal FieldDescriptorProto Proto { get { return proto; } }
+
+        /// <summary>
+        /// Returns the accessor for this field.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// While a <see cref="FieldDescriptor"/> describes the field, it does not provide
+        /// any way of obtaining or changing the value of the field within a specific message;
+        /// that is the responsibility of the accessor.
+        /// </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. This is not represented in any
+        /// generated type, and the value of the map field itself is represented by a dictionary in the
+        /// reflection API. There are never instances of those "hidden" messages, so no accessor is provided
+        /// and this property will return null.
+        /// </para>
+        /// </remarks>
+        public IFieldAccessor Accessor { get { return accessor; } }
+        
+        /// <summary>
+        /// Maps a field type as included in the .proto file to a FieldType.
+        /// </summary>
+        private static FieldType GetFieldTypeFromProtoType(FieldDescriptorProto.Types.Type type)
+        {
+            switch (type)
+            {
+                case FieldDescriptorProto.Types.Type.TYPE_DOUBLE:
+                    return FieldType.Double;
+                case FieldDescriptorProto.Types.Type.TYPE_FLOAT:
+                    return FieldType.Float;
+                case FieldDescriptorProto.Types.Type.TYPE_INT64:
+                    return FieldType.Int64;
+                case FieldDescriptorProto.Types.Type.TYPE_UINT64:
+                    return FieldType.UInt64;
+                case FieldDescriptorProto.Types.Type.TYPE_INT32:
+                    return FieldType.Int32;
+                case FieldDescriptorProto.Types.Type.TYPE_FIXED64:
+                    return FieldType.Fixed64;
+                case FieldDescriptorProto.Types.Type.TYPE_FIXED32:
+                    return FieldType.Fixed32;
+                case FieldDescriptorProto.Types.Type.TYPE_BOOL:
+                    return FieldType.Bool;
+                case FieldDescriptorProto.Types.Type.TYPE_STRING:
+                    return FieldType.String;
+                case FieldDescriptorProto.Types.Type.TYPE_GROUP:
+                    return FieldType.Group;
+                case FieldDescriptorProto.Types.Type.TYPE_MESSAGE:
+                    return FieldType.Message;
+                case FieldDescriptorProto.Types.Type.TYPE_BYTES:
+                    return FieldType.Bytes;
+                case FieldDescriptorProto.Types.Type.TYPE_UINT32:
+                    return FieldType.UInt32;
+                case FieldDescriptorProto.Types.Type.TYPE_ENUM:
+                    return FieldType.Enum;
+                case FieldDescriptorProto.Types.Type.TYPE_SFIXED32:
+                    return FieldType.SFixed32;
+                case FieldDescriptorProto.Types.Type.TYPE_SFIXED64:
+                    return FieldType.SFixed64;
+                case FieldDescriptorProto.Types.Type.TYPE_SINT32:
+                    return FieldType.SInt32;
+                case FieldDescriptorProto.Types.Type.TYPE_SINT64:
+                    return FieldType.SInt64;
+                default:
+                    throw new ArgumentException("Invalid type specified");
+            }
+        }
+
+        /// <summary>
+        /// Returns <c>true</c> if this field is a repeated field; <c>false</c> otherwise.
+        /// </summary>
+        public bool IsRepeated
+        {
+            get { return Proto.Label == FieldDescriptorProto.Types.Label.LABEL_REPEATED; }
+        }
+
+        /// <summary>
+        /// Returns <c>true</c> if this field is a map field; <c>false</c> otherwise.
+        /// </summary>
+        public bool IsMap
+        {
+            get { return fieldType == FieldType.Message && messageType.Proto.Options != null && messageType.Proto.Options.MapEntry; }
+        }
+
+        /// <summary>
+        /// Returns <c>true</c> if this field is a packed, repeated field; <c>false</c> otherwise.
+        /// </summary>
+        public bool IsPacked
+        {
+            // Note the || rather than && here - we're effectively defaulting to packed, because that *is*
+            // the default in proto3, which is all we support. We may give the wrong result for the protos
+            // within descriptor.proto, but that's okay, as they're never exposed and we don't use IsPacked
+            // within the runtime.
+            get { return Proto.Options == null || Proto.Options.Packed; }
+        }        
+
+        /// <summary>
+        /// Get the field's containing message type.
+        /// </summary>
+        public MessageDescriptor ContainingType
+        {
+            get { return containingType; }
+        }
+
+        /// <summary>
+        /// Returns the oneof containing this field, or <c>null</c> if it is not part of a oneof.
+        /// </summary>
+        public OneofDescriptor ContainingOneof
+        {
+            get { return containingOneof; }
+        }
+
+        /// <summary>
+        /// Returns the type of the field.
+        /// </summary>
+        public FieldType FieldType
+        {
+            get { return fieldType; }
+        }
+
+        /// <summary>
+        /// Returns the field number declared in the proto file.
+        /// </summary>
+        public int FieldNumber
+        {
+            get { return Proto.Number; }
+        }
+
+        /// <summary>
+        /// Compares this descriptor with another one, ordering in "canonical" order
+        /// which simply means ascending order by field number. <paramref name="other"/>
+        /// must be a field of the same type, i.e. the <see cref="ContainingType"/> of
+        /// both fields must be the same.
+        /// </summary>
+        public int CompareTo(FieldDescriptor other)
+        {
+            if (other.containingType != containingType)
+            {
+                throw new ArgumentException("FieldDescriptors can only be compared to other FieldDescriptors " +
+                                            "for fields of the same message type.");
+            }
+            return FieldNumber - other.FieldNumber;
+        }
+
+        /// <summary>
+        /// For enum fields, returns the field's type.
+        /// </summary>
+        public EnumDescriptor EnumType
+        {
+            get
+            {
+                if (fieldType != FieldType.Enum)
+                {
+                    throw new InvalidOperationException("EnumType is only valid for enum fields.");
+                }
+                return enumType;
+            }
+        }
+
+        /// <summary>
+        /// For embedded message and group fields, returns the field's type.
+        /// </summary>
+        public MessageDescriptor MessageType
+        {
+            get
+            {
+                if (fieldType != FieldType.Message)
+                {
+                    throw new InvalidOperationException("MessageType is only valid for message fields.");
+                }
+                return messageType;
+            }
+        }
+
+        /// <summary>
+        /// Look up and cross-link all field types etc.
+        /// </summary>
+        internal void CrossLink()
+        {
+            if (Proto.TypeName != "")
+            {
+                IDescriptor typeDescriptor =
+                    File.DescriptorPool.LookupSymbol(Proto.TypeName, this);
+
+                if (Proto.Type != 0)
+                {
+                    // Choose field type based on symbol.
+                    if (typeDescriptor is MessageDescriptor)
+                    {
+                        fieldType = FieldType.Message;
+                    }
+                    else if (typeDescriptor is EnumDescriptor)
+                    {
+                        fieldType = FieldType.Enum;
+                    }
+                    else
+                    {
+                        throw new DescriptorValidationException(this, $"\"{Proto.TypeName}\" is not a type.");
+                    }
+                }
+
+                if (fieldType == FieldType.Message)
+                {
+                    if (!(typeDescriptor is MessageDescriptor))
+                    {
+                        throw new DescriptorValidationException(this, $"\"{Proto.TypeName}\" is not a message type.");
+                    }
+                    messageType = (MessageDescriptor) typeDescriptor;
+
+                    if (Proto.DefaultValue != "")
+                    {
+                        throw new DescriptorValidationException(this, "Messages can't have default values.");
+                    }
+                }
+                else if (fieldType == FieldType.Enum)
+                {
+                    if (!(typeDescriptor is EnumDescriptor))
+                    {
+                        throw new DescriptorValidationException(this, $"\"{Proto.TypeName}\" is not an enum type.");
+                    }
+                    enumType = (EnumDescriptor) typeDescriptor;
+                }
+                else
+                {
+                    throw new DescriptorValidationException(this, "Field with primitive type has type_name.");
+                }
+            }
+            else
+            {
+                if (fieldType == FieldType.Message || fieldType == FieldType.Enum)
+                {
+                    throw new DescriptorValidationException(this, "Field with message or enum type missing type_name.");
+                }
+            }
+
+            // Note: no attempt to perform any default value parsing
+
+            File.DescriptorPool.AddFieldByNumber(this);
+
+            if (containingType != null && containingType.Proto.Options != null && containingType.Proto.Options.MessageSetWireFormat)
+            {
+                throw new DescriptorValidationException(this, "MessageSet format is not supported.");
+            }
+            accessor = CreateAccessor(propertyName);
+        }
+
+        private IFieldAccessor CreateAccessor(string propertyName)
+        {
+            // If we're given no property name, that's because we really don't want an accessor.
+            // (At the moment, that means it's a map entry message...)
+            if (propertyName == null)
+            {
+                return null;
+            }
+            var property = containingType.ClrType.GetProperty(propertyName);
+            if (property == null)
+            {
+                throw new DescriptorValidationException(this, $"Property {propertyName} not found in {containingType.ClrType}");
+            }
+            return IsMap ? new MapFieldAccessor(property, this)
+                : IsRepeated ? new RepeatedFieldAccessor(property, this)
+                : (IFieldAccessor) new SingleFieldAccessor(property, this);
+        }
+    }
+}