/// <summary>
/// Look up and cross-link all field types etc.
/// </summary>
internal void CrossLink()
{
if (Proto.HasTypeName)
{
IDescriptor typeDescriptor =
File.DescriptorPool.LookupSymbol(Proto.TypeName, this);
if (Proto.HasType)
{
// 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 || fieldType == FieldType.Group)
{
if (!(typeDescriptor is MessageDescriptor))
{
throw new DescriptorValidationException(this, $"\"{Proto.TypeName}\" is not a message type.");
}
messageType = (MessageDescriptor)typeDescriptor;
if (Proto.HasDefaultValue)
{
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.");
}
}
if (Proto.HasExtendee)
{
extendeeType = File.DescriptorPool.LookupSymbol(Proto.Extendee, this) as MessageDescriptor;
}
// 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();
}
