csharp-sdk-upm/Libs/Google.Protobuf/Reflection/OneofAccessor.cs

98 lines
4.1 KiB
C#

#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2015 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.Reflection;
using LC.Google.Protobuf.Compatibility;
namespace LC.Google.Protobuf.Reflection
{
/// <summary>
/// Reflection access for a oneof, allowing clear and "get case" actions.
/// </summary>
public sealed class OneofAccessor
{
private readonly Func<IMessage, int> caseDelegate;
private readonly Action<IMessage> clearDelegate;
private OneofAccessor(OneofDescriptor descriptor, Func<IMessage, int> caseDelegate, Action<IMessage> clearDelegate)
{
Descriptor = descriptor;
this.caseDelegate = caseDelegate;
this.clearDelegate = clearDelegate;
}
internal static OneofAccessor ForRegularOneof(
OneofDescriptor descriptor,
PropertyInfo caseProperty,
MethodInfo clearMethod) =>
new OneofAccessor(
descriptor,
ReflectionUtil.CreateFuncIMessageInt32(caseProperty.GetGetMethod()),
ReflectionUtil.CreateActionIMessage(clearMethod));
internal static OneofAccessor ForSyntheticOneof(OneofDescriptor descriptor)
{
// Note: descriptor.Fields will be null when this method is called, because we haven't
// cross-linked yet. But by the time the delegates are called by user code, all will be
// well. (That's why we capture the descriptor itself rather than a field.)
return new OneofAccessor(descriptor,
message => descriptor.Fields[0].Accessor.HasValue(message) ? descriptor.Fields[0].FieldNumber : 0,
message => descriptor.Fields[0].Accessor.Clear(message));
}
/// <summary>
/// Gets the descriptor for this oneof.
/// </summary>
/// <value>
/// The descriptor of the oneof.
/// </value>
public OneofDescriptor Descriptor { get; }
/// <summary>
/// Clears the oneof in the specified message.
/// </summary>
public void Clear(IMessage message) => clearDelegate(message);
/// <summary>
/// Indicates which field in the oneof is set for specified message
/// </summary>
public FieldDescriptor GetCaseFieldDescriptor(IMessage message)
{
int fieldNumber = caseDelegate(message);
return fieldNumber > 0
? Descriptor.ContainingType.FindFieldByNumber(fieldNumber)
: null;
}
}
}