[sldev] message_template.msg ordering and packing : attentionLLfolks

[John Hurliman]

Rob Lanphier wrote:
> Zero Linden (Mark Lentczner) is currently holding office hours regularly
> in world...see his email from yesterday.  A bunch of folks from LL are
> working on big protocol improvements, exactly along the lines that you
> describe.
>
> Hopefully we can bridge the gap between the email discussion going on
> here, and the work that he's doing there.  Best thoughts on how to do that?
>
> Rob

The LLSD serialization/deserialization as it is proposed in Zero's 
diagrams is built on top of the message_template.msg system instead of 
replacing it (such as the CAPS system mostly does). It doesn't address 
the fragile and obscure field/block ordering in the template file, and 
real-time lossy packets like AgentUpdate will always be vulnerable to 
field/block reordering. While the LLSD serialization, CAPS system, and 
all the new protocol stuff going on is really interesting, it doesn't 
make the original issue brought up in this thread go away. The two main 
issues I see in this thread are simplifying the protocol in to something 
documentable (imagine writing protocol documentation that says "throw 
all of these in to a std::map and the results will magically be 
produced. Wait, you're not using C++ and the STL to implement the 
protocol? Oh... that's too bad") and hardening the real-time lossy part 
of the protocol against future changes (is moving away from the 
all-or-nothing approach of comparing a hash of the message template 
desirable, and how do we do it). Those two goals may or may not be 
related, and everyone likely has different feelings on how important 
each one is.

John Hurliman