Reflection::AddMessage() will automatically allocate the correct type -- you don't have to do it yourself. In fact, you aren't allowed to do it yourself. (The Message* which you pass to AddMessage() is supposed to point at the *parent* message, just like with all the other reflection methods.) In general, though, MessageFactory provides a way to allocate a Message object for a given Descriptor.
http://code.google.com/apis/protocolbuffers/docs/reference/cpp/google.protobuf.message.html#MessageFactory On Tue, Oct 13, 2009 at 2:35 PM, Jason Smith <jasonfsmi...@gmail.com> wrote: > > I wrote a generic proto-to-xml routine (using TinyXML) that'll convert > any Message* into XML. Thanks to the reflection interface and > TextFormat, it was pretty straightforward. (if there's interest in > seeing it let me know... I'll clear it with my boss and post to this > forum). > > Now I'm trying to do the reverse, and I'm having issues with repeated > fields that are themselves messages. When parsing the XML it finds a > repeated message, but I can't figure out what method to call in order > to automagically create a new object of the correct derived Message > type for this repeated field. The goal is to call > Reflection::AddMessage(), then recursively call my XmlToProto() > routine on this new object, parsing any children in the XML tree. > > I was looking for a method in either the Descriptor or Reflection > interfaces to allocate a new object of the right Message-derived type > (obviously it would have to then return it a a Message*, which is > fine), but didn't see anything. Can someone point me in the right > direction? > > Thanks in advance, > -Jason > > On Sep 29, 6:06 am, sim <simon.we...@gmail.com> wrote: > > Cool. New syntax I didn't know about! I think this would be useful > > for converting the other way around (Proto-to-XML). > > > > On Sep 28, 6:05 pm, Kenton Varda <ken...@google.com> wrote: > > > > > Interesting. > > > > > Another way to do this would be to write code based on protobuf > reflection > > > and custom options, so you could have a proto like: > > > message Foo { > > > optional int32 i = 1 [(xml_disposition) = ATTRIBUTE]; > > > optional Bar bar = 2 [(xml_disposition) = ELEMENT]; > > > } > > > > > On Mon, Sep 28, 2009 at 6:14 AM, sim <simon.we...@gmail.com> wrote: > > > > > > Hi all. Would anybody be interested in an XML to Protocol Buffers > > > > converter if it were opened up to the community? I have an XML > > > > stylesheet that transforms an annotated XSD set into a Java class > that > > > > uses JAXB and the Protocol Buffers Java API to convert XML documents > > > > into either text or binary mode Protocol Buffers messages. The XSD > > > > annotations define the mappings from XSD elements to Proto messages > > > > (although at present staying close to a 1:1 mapping is probably > > > > safest). Some fancy XSD features are not yet supported but the usual > > > > complexTypes, simpleTypes, elements, and enumerations work. > > > > > > Simon Weeks > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to protobuf@googlegroups.com To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/protobuf?hl=en -~----------~----~----~----~------~----~------~--~---
