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Diffstat (limited to 'csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs')
| -rw-r--r-- | csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs new file mode 100644 index 00000000..901cbf47 --- /dev/null +++ b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs @@ -0,0 +1,350 @@ +#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, or <c>null</c> if this descriptor does + /// not support reflective access. + /// </summary> + /// <remarks> + /// 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. + /// </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 enum 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 (containingType.GeneratedType == null || propertyName == null) + { + return null; + } + var property = containingType.GeneratedType.GetProperty(propertyName); + if (property == null) + { + throw new DescriptorValidationException(this, "Property " + propertyName + " not found in " + containingType.GeneratedType); + } + return IsMap ? new MapFieldAccessor(property, this) + : IsRepeated ? new RepeatedFieldAccessor(property, this) + : (IFieldAccessor) new SingleFieldAccessor(property, this); + } + } +}
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