1 #region Copyright notice and license 2 // Protocol Buffers - Google's data interchange format 3 // Copyright 2015 Google Inc. All rights reserved. 4 // https://developers.google.com/protocol-buffers/ 5 // 6 // Redistribution and use in source and binary forms, with or without 7 // modification, are permitted provided that the following conditions are 8 // met: 9 // 10 // * Redistributions of source code must retain the above copyright 11 // notice, this list of conditions and the following disclaimer. 12 // * Redistributions in binary form must reproduce the above 13 // copyright notice, this list of conditions and the following disclaimer 14 // in the documentation and/or other materials provided with the 15 // distribution. 16 // * Neither the name of Google Inc. nor the names of its 17 // contributors may be used to endorse or promote products derived from 18 // this software without specific prior written permission. 19 // 20 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 23 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 24 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 25 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 26 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 #endregion 32 33 using System; 34 using System.Reflection; 35 using Google.Protobuf.Compatibility; 36 37 namespace Google.Protobuf.Reflection 38 { 39 /// <summary> 40 /// Reflection access for a oneof, allowing clear and "get case" actions. 41 /// </summary> 42 public sealed class OneofAccessor 43 { 44 private readonly Func<IMessage, int> caseDelegate; 45 private readonly Action<IMessage> clearDelegate; 46 OneofAccessor(OneofDescriptor descriptor, Func<IMessage, int> caseDelegate, Action<IMessage> clearDelegate)47 private OneofAccessor(OneofDescriptor descriptor, Func<IMessage, int> caseDelegate, Action<IMessage> clearDelegate) 48 { 49 Descriptor = descriptor; 50 this.caseDelegate = caseDelegate; 51 this.clearDelegate = clearDelegate; 52 } 53 ForRegularOneof( OneofDescriptor descriptor, PropertyInfo caseProperty, MethodInfo clearMethod)54 internal static OneofAccessor ForRegularOneof( 55 OneofDescriptor descriptor, 56 PropertyInfo caseProperty, 57 MethodInfo clearMethod) => 58 new OneofAccessor( 59 descriptor, 60 ReflectionUtil.CreateFuncIMessageInt32(caseProperty.GetGetMethod()), 61 ReflectionUtil.CreateActionIMessage(clearMethod)); 62 ForSyntheticOneof(OneofDescriptor descriptor)63 internal static OneofAccessor ForSyntheticOneof(OneofDescriptor descriptor) 64 { 65 // Note: descriptor.Fields will be null when this method is called, because we haven't 66 // cross-linked yet. But by the time the delgates are called by user code, all will be 67 // well. (That's why we capture the descriptor itself rather than a field.) 68 return new OneofAccessor(descriptor, 69 message => descriptor.Fields[0].Accessor.HasValue(message) ? descriptor.Fields[0].FieldNumber : 0, 70 message => descriptor.Fields[0].Accessor.Clear(message)); 71 } 72 73 /// <summary> 74 /// Gets the descriptor for this oneof. 75 /// </summary> 76 /// <value> 77 /// The descriptor of the oneof. 78 /// </value> 79 public OneofDescriptor Descriptor { get; } 80 81 /// <summary> 82 /// Clears the oneof in the specified message. 83 /// </summary> 84 public void Clear(IMessage message) => clearDelegate(message); 85 86 /// <summary> 87 /// Indicates which field in the oneof is set for specified message 88 /// </summary> GetCaseFieldDescriptor(IMessage message)89 public FieldDescriptor GetCaseFieldDescriptor(IMessage message) 90 { 91 int fieldNumber = caseDelegate(message); 92 return fieldNumber > 0 93 ? Descriptor.ContainingType.FindFieldByNumber(fieldNumber) 94 : null; 95 } 96 } 97 } 98