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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.
// http://code.google.com/p/protobuf/
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
using System.Collections.Generic;
using Google.ProtocolBuffers.DescriptorProtos;
namespace Google.ProtocolBuffers.Descriptors {
/// <summary>
/// Describes a message type.
/// </summary>
public sealed class MessageDescriptor : IndexedDescriptorBase<DescriptorProto, MessageOptions> {
private readonly MessageDescriptor containingType;
private readonly IList<MessageDescriptor> nestedTypes;
private readonly IList<EnumDescriptor> enumTypes;
private readonly IList<FieldDescriptor> fields;
private readonly IList<FieldDescriptor> extensions;
private bool hasRequiredFields;
internal MessageDescriptor(DescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int typeIndex)
: base(proto, file, ComputeFullName(file, parent, proto.Name), typeIndex) {
containingType = parent;
nestedTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.NestedTypeList,
(type, index) => new MessageDescriptor(type, file, this, index));
enumTypes = DescriptorUtil.ConvertAndMakeReadOnly(proto.EnumTypeList,
(type, index) => new EnumDescriptor(type, file, this, index));
fields = DescriptorUtil.ConvertAndMakeReadOnly(proto.FieldList,
(field, index) => new FieldDescriptor(field, file, this, index, false));
extensions = DescriptorUtil.ConvertAndMakeReadOnly(proto.ExtensionList,
(field, index) => new FieldDescriptor(field, file, this, index, true));
file.DescriptorPool.AddSymbol(this);
}
/// <value>
/// If this is a nested type, get the outer descriptor, otherwise null.
/// </value>
public MessageDescriptor ContainingType {
get { return containingType; }
}
/// <value>
/// An unmodifiable list of this message type's fields.
/// </value>
public IList<FieldDescriptor> Fields {
get { return fields; }
}
/// <value>
/// An unmodifiable list of this message type's extensions.
/// </value>
public IList<FieldDescriptor> Extensions {
get { return extensions; }
}
/// <value>
/// An unmodifiable list of this message type's nested types.
/// </value>
public IList<MessageDescriptor> NestedTypes {
get { return nestedTypes; }
}
/// <value>
/// An unmodifiable list of this message type's enum types.
/// </value>
public IList<EnumDescriptor> EnumTypes {
get { return enumTypes; }
}
/// <summary>
/// Returns a pre-computed result as to whether this message
/// has required fields. This includes optional fields which are
/// message types which in turn have required fields, and any
/// extension fields.
/// </summary>
internal bool HasRequiredFields {
get { return hasRequiredFields; }
}
/// <summary>
/// Determines if the given field number is an extension.
/// </summary>
public bool IsExtensionNumber(int number) {
foreach (DescriptorProto.Types.ExtensionRange range in Proto.ExtensionRangeList) {
if (range.Start <= number && number < range.End) {
return true;
}
}
return false;
}
/// <summary>
/// Finds a field by field number.
/// </summary>
/// <param name="number">The field number within this message type.</param>
/// <returns>The field's descriptor, or null if not found.</returns>
public FieldDescriptor FindFieldByNumber(int number) {
return File.DescriptorPool.FindFieldByNumber(this, number);
}
/// <summary>
/// Finds a nested descriptor by name. The is valid for fields, nested
/// message types and enums.
/// </summary>
/// <param name="name">The unqualified name of the descriptor, e.g. "Foo"</param>
/// <returns>The descriptor, or null if not found.</returns>
public T FindDescriptor<T>(string name)
where T : class, IDescriptor {
return File.DescriptorPool.FindSymbol<T>(FullName + "." + name);
}
/// <summary>
/// Looks up and cross-links all fields, nested types, and extensions.
/// </summary>
internal void CrossLink() {
foreach (MessageDescriptor message in nestedTypes) {
message.CrossLink();
}
foreach (FieldDescriptor field in fields) {
field.CrossLink();
}
foreach (FieldDescriptor extension in extensions) {
extension.CrossLink();
}
}
internal void CheckRequiredFields() {
IDictionary<MessageDescriptor, byte> alreadySeen = new Dictionary<MessageDescriptor, byte>();
hasRequiredFields = CheckRequiredFields(alreadySeen);
}
private bool CheckRequiredFields(IDictionary<MessageDescriptor,byte> alreadySeen) {
if (alreadySeen.ContainsKey(this)) {
// The type is already in the cache. This means that either:
// a. The type has no required fields.
// b. We are in the midst of checking if the type has required fields,
// somewhere up the stack. In this case, we know that if the type
// has any required fields, they'll be found when we return to it,
// and the whole call to HasRequiredFields() will return true.
// Therefore, we don't have to check if this type has required fields
// here.
return false;
}
alreadySeen[this] = 0; // Value is irrelevant; we want set semantics
// If the type allows extensions, an extension with message type could contain
// required fields, so we have to be conservative and assume such an
// extension exists.
if (Proto.ExtensionRangeCount != 0) {
return true;
}
foreach (FieldDescriptor field in Fields) {
if (field.IsRequired) {
return true;
}
if (field.MappedType == MappedType.Message) {
if (field.MessageType.CheckRequiredFields(alreadySeen)) {
return true;
}
}
}
return false;
}
}
}
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