To parse protos at runtime you will either need to use C++, or you will need to invoke protoc as a subprocess and have it output a FileDecsriptorSet which you can use in Java or other languages. I'll assume C++.
Be sure to get familiar with the API documentation here: http://code.google.com/apis/protocolbuffers/docs/reference/cpp/index.html#google.protobuf There are basically two steps here: (1) Parse the files to produce descriptors. Descriptors (a family of classes defined in descriptor.h) are data structures representing parsed .proto files. For this step, you want to use the Importer class found in importer.h. Assuming your proto files are located on-disk, you'll want to give it a DiskSourceTree -- but you can provide your own SourceTree implementation if your files are located somewhere else. (2) Use descriptors to construct DynamicMessages. DynamicMessage is an implementation of the Message interface which mimics a type given by a descriptor. Actually, the DynamicMessage class itself is private -- the class you will use is DynamicMessageFactory, defined in dynamic_message.h. This is just a simple factory which takes a Descriptor and returns a default instance of that class. You can then call New() on that default instance to construct a mutable instance. The message can be modified via the Reflection interface as defined in message.h. This may sound complicated but it actually comes down to only a few lines of code. On Tue, Dec 1, 2009 at 10:27 AM, David McClurg <[email protected]>wrote: > I'm trying to rebuild a message editor for a game engine using > protocol buffers. Currently we are using an XML template to describe > the message type and XML to store the message. I like the protocol > buffer language ( .proto files ) as well as the memory and performance > advantages over XML. > > The tricky part is the message editor. The message editor tool needs > to... > 1) parse all .proto files for the game > 2) present the user with a input form for a selected message type > 3) build a protocol message > 4) save the message to disk for the game to load. > > The property editor doesn't know about any message types at compile > time. The game knows about all message types at compile time. For > the message editor, message types need to be dynamically generated > from .proto files. For the game, messages are read from disk and used > to construct game objects and populate the world. > > From other discussions, I've read this is possible but not obvious > with protocol buffers. > > Could you please explain in specific terms how to parse a bunch > of .proto files from disk into message types at runtime? How do I > parse .proto files on-the-fly? > > Thanks, > David > > -- > > You received this message because you are subscribed to the Google Groups > "Protocol Buffers" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<protobuf%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > > > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
