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.Diagnostics; 35 using System.Diagnostics.CodeAnalysis; 36 using System.Reflection; 37 using Google.Protobuf.Compatibility; 38 39 namespace Google.Protobuf.Reflection 40 { 41 /// <summary> 42 /// Accessor for single fields. 43 /// </summary> 44 internal sealed class SingleFieldAccessor : FieldAccessorBase 45 { 46 // All the work here is actually done in the constructor - it creates the appropriate delegates. 47 // There are various cases to consider, based on the property type (message, string/bytes, or "genuine" primitive) 48 // and proto2 vs proto3 for non-message types, as proto3 doesn't support "full" presence detection or default 49 // values. 50 51 private readonly Action<IMessage, object> setValueDelegate; 52 private readonly Action<IMessage> clearDelegate; 53 private readonly Func<IMessage, bool> hasDelegate; 54 SingleFieldAccessor( [DynamicallyAccessedMembers(GeneratedClrTypeInfo.MessageAccessibility)] Type messageType, PropertyInfo property, FieldDescriptor descriptor)55 internal SingleFieldAccessor( 56 [DynamicallyAccessedMembers(GeneratedClrTypeInfo.MessageAccessibility)] 57 Type messageType, PropertyInfo property, FieldDescriptor descriptor) : base(property, descriptor) 58 { 59 if (!property.CanWrite) 60 { 61 throw new ArgumentException("Not all required properties/methods available"); 62 } 63 setValueDelegate = ReflectionUtil.CreateActionIMessageObject(property.GetSetMethod()); 64 65 // Note: this looks worrying in that we access the containing oneof, which isn't valid until cross-linking 66 // is complete... but field accessors aren't created until after cross-linking. 67 // The oneof itself won't be cross-linked yet, but that's okay: the oneof accessor is created 68 // earlier. 69 70 // Message fields always support presence, via null checks. 71 if (descriptor.FieldType == FieldType.Message) 72 { 73 hasDelegate = message => GetValue(message) != null; 74 clearDelegate = message => SetValue(message, null); 75 } 76 // Oneof fields always support presence, via case checks. 77 // Note that clearing the field is a no-op unless that specific field is the current "case". 78 else if (descriptor.RealContainingOneof != null) 79 { 80 var oneofAccessor = descriptor.RealContainingOneof.Accessor; 81 hasDelegate = message => oneofAccessor.GetCaseFieldDescriptor(message) == descriptor; 82 clearDelegate = message => 83 { 84 // Clear on a field only affects the oneof itself if the current case is the field we're accessing. 85 if (oneofAccessor.GetCaseFieldDescriptor(message) == descriptor) 86 { 87 oneofAccessor.Clear(message); 88 } 89 }; 90 } 91 // Primitive fields always support presence in proto2, and support presence in proto3 for optional fields. 92 else if (descriptor.File.Syntax == Syntax.Proto2 || descriptor.Proto.Proto3Optional) 93 { 94 MethodInfo hasMethod = messageType.GetRuntimeProperty("Has" + property.Name).GetMethod; 95 if (hasMethod == null) 96 { 97 throw new ArgumentException("Not all required properties/methods are available"); 98 } 99 hasDelegate = ReflectionUtil.CreateFuncIMessageBool(hasMethod); 100 MethodInfo clearMethod = messageType.GetRuntimeMethod("Clear" + property.Name, ReflectionUtil.EmptyTypes); 101 if (clearMethod == null) 102 { 103 throw new ArgumentException("Not all required properties/methods are available"); 104 } 105 clearDelegate = ReflectionUtil.CreateActionIMessage(clearMethod); 106 } 107 // What's left? 108 // Primitive proto3 fields without the optional keyword, which aren't in oneofs. 109 else 110 { 111 hasDelegate = message => { throw new InvalidOperationException("Presence is not implemented for this field"); }; 112 113 // While presence isn't supported, clearing still is; it's just setting to a default value. 114 object defaultValue = GetDefaultValue(descriptor); 115 clearDelegate = message => SetValue(message, defaultValue); 116 } 117 } 118 GetDefaultValue(FieldDescriptor descriptor)119 private static object GetDefaultValue(FieldDescriptor descriptor) 120 { 121 switch (descriptor.FieldType) 122 { 123 case FieldType.Bool: 124 return false; 125 case FieldType.Bytes: 126 return ByteString.Empty; 127 case FieldType.String: 128 return ""; 129 case FieldType.Double: 130 return 0.0; 131 case FieldType.SInt32: 132 case FieldType.Int32: 133 case FieldType.SFixed32: 134 case FieldType.Enum: 135 return 0; 136 case FieldType.Fixed32: 137 case FieldType.UInt32: 138 return (uint)0; 139 case FieldType.Fixed64: 140 case FieldType.UInt64: 141 return 0UL; 142 case FieldType.SFixed64: 143 case FieldType.Int64: 144 case FieldType.SInt64: 145 return 0L; 146 case FieldType.Float: 147 return 0f; 148 case FieldType.Message: 149 case FieldType.Group: // Never expect to get this, but... 150 return null; 151 default: 152 throw new ArgumentException("Invalid field type"); 153 } 154 } 155 156 public override void Clear(IMessage message) => clearDelegate(message); 157 public override bool HasValue(IMessage message) => hasDelegate(message); SetValue(IMessage message, object value)158 public override void SetValue(IMessage message, object value) => setValueDelegate(message, value); 159 } 160 } 161