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#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2015 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#endregion
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using Google.Protobuf.Collections;
using Google.Protobuf.Compatibility;
namespace Google.Protobuf.Reflection
{
/// <summary>
/// Describes a "oneof" field collection in a message type: a set of
/// fields of which at most one can be set in any particular message.
/// </summary>
public sealed class OneofDescriptor : DescriptorBase
{
private MessageDescriptor containingType;
private IList<FieldDescriptor> fields;
private readonly OneofAccessor accessor;
internal OneofDescriptor(OneofDescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int index, string clrName)
: base(file, file.ComputeFullName(parent, proto.Name), index, parent.Features.MergedWith(proto.Options?.Features))
{
this.Proto = proto;
containingType = parent;
file.DescriptorPool.AddSymbol(this);
// It's useful to determine whether or not this is a synthetic oneof before cross-linking. That means
// diving into the proto directly rather than using FieldDescriptor, but that's okay.
var firstFieldInOneof = parent.Proto.Field.FirstOrDefault(fieldProto => fieldProto.HasOneofIndex && fieldProto.OneofIndex == index);
IsSynthetic = firstFieldInOneof?.Proto3Optional ?? false;
accessor = CreateAccessor(clrName);
}
/// <summary>
/// The brief name of the descriptor's target.
/// </summary>
public override string Name => Proto.Name;
// Visible for testing
internal OneofDescriptorProto Proto { get; }
/// <summary>
/// Returns a clone of the underlying <see cref="OneofDescriptorProto"/> describing this oneof.
/// Note that a copy is taken every time this method is called, so clients using it frequently
/// (and not modifying it) may want to cache the returned value.
/// </summary>
/// <returns>A protobuf representation of this oneof descriptor.</returns>
public OneofDescriptorProto ToProto() => Proto.Clone();
/// <summary>
/// Gets the message type containing this oneof.
/// </summary>
/// <value>
/// The message type containing this oneof.
/// </value>
public MessageDescriptor ContainingType
{
get { return containingType; }
}
/// <summary>
/// Gets the fields within this oneof, in declaration order.
/// </summary>
/// <value>
/// The fields within this oneof, in declaration order.
/// </value>
public IList<FieldDescriptor> Fields { get { return fields; } }
/// <summary>
/// Returns <c>true</c> if this oneof is a synthetic oneof containing a proto3 optional field;
/// <c>false</c> otherwise.
/// </summary>
public bool IsSynthetic { get; }
/// <summary>
/// Gets an accessor for reflective access to the values associated with the oneof
/// in a particular message.
/// </summary>
/// <remarks>
/// <para>
/// In descriptors for generated code, the value returned by this property will always be non-null.
/// </para>
/// <para>
/// In dynamically loaded descriptors, the value returned by this property will current be null;
/// if and when dynamic messages are supported, it will return a suitable accessor to work with
/// them.
/// </para>
/// </remarks>
/// <value>
/// The accessor used for reflective access.
/// </value>
public OneofAccessor Accessor { get { return accessor; } }
/// <summary>
/// The (possibly empty) set of custom options for this oneof.
/// </summary>
[Obsolete("CustomOptions are obsolete. Use the GetOptions method.")]
public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
/// <summary>
/// The <c>OneofOptions</c>, defined in <c>descriptor.proto</c>.
/// If the options message is not present (i.e. there are no options), <c>null</c> is returned.
/// Custom options can be retrieved as extensions of the returned message.
/// NOTE: A defensive copy is created each time this property is retrieved.
/// </summary>
public OneofOptions GetOptions()
{
var clone = Proto.Options?.Clone();
if (clone is null)
{
return null;
}
// Clients should be using feature accessor methods, not accessing features on the
// options proto.
clone.Features = null;
return clone;
}
/// <summary>
/// Gets a single value oneof option for this descriptor
/// </summary>
[Obsolete("GetOption is obsolete. Use the GetOptions() method.")]
public T GetOption<T>(Extension<OneofOptions, T> extension)
{
var value = Proto.Options.GetExtension(extension);
return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
}
/// <summary>
/// Gets a repeated value oneof option for this descriptor
/// </summary>
[Obsolete("GetOption is obsolete. Use the GetOptions() method.")]
public RepeatedField<T> GetOption<T>(RepeatedExtension<OneofOptions, T> extension)
{
return Proto.Options.GetExtension(extension).Clone();
}
internal void CrossLink()
{
List<FieldDescriptor> fieldCollection = new List<FieldDescriptor>();
foreach (var field in ContainingType.Fields.InDeclarationOrder())
{
if (field.ContainingOneof == this)
{
fieldCollection.Add(field);
}
}
fields = new ReadOnlyCollection<FieldDescriptor>(fieldCollection);
}
private OneofAccessor CreateAccessor(string clrName)
{
// We won't have a CLR name if this is from a dynamically-loaded FileDescriptor.
// TODO: Support dynamic messages.
if (clrName == null)
{
return null;
}
if (IsSynthetic)
{
return OneofAccessor.ForSyntheticOneof(this);
}
else
{
var caseProperty = containingType.ClrType.GetProperty(clrName + "Case");
if (caseProperty == null)
{
throw new DescriptorValidationException(this, $"Property {clrName}Case not found in {containingType.ClrType}");
}
if (!caseProperty.CanRead)
{
throw new ArgumentException($"Cannot read from property {clrName}Case in {containingType.ClrType}");
}
var clearMethod = containingType.ClrType.GetMethod("Clear" + clrName);
if (clearMethod == null)
{
throw new DescriptorValidationException(this, $"Method Clear{clrName} not found in {containingType.ClrType}");
}
return OneofAccessor.ForRegularOneof(this, caseProperty, clearMethod);
}
}
}
}