Before anything else, let me state this: Of course it's going to be PAINFULLY slow on MRI. That's not the point :)
I thought I'd try out writing out a Ruby version of the parser for the purposes of Rubinius. For those of you who aren't aware, Ragel supports a goto-driven FSM on Rubinius by injecting assembly directly, and Rubinus head honcho guy Evan Phoenix is working on a patch for Ragel to update it to the new compiler semantics. So really, there is a purpose for trying this out.
Anyway, here's my initial hack. It's nasty, and presently jams the entire FSM into instance-specific data. Aieee! But it more or less seems to generate similar (albeit not identical) output to the C one:
http://git.rubini.us/?p=code;a=blob;f=lib/mongrel/http11_parser.rb.rl;h=508f9bd42b4aad322f357637d52576f780707a2f;hb=868732662abbf4aa571bf2f3d598152467f6f4da
I've thought about having a Mongrel::HttpParser::FSM module to store
the actual Ragel-generated state machine, and pass all ivars from the
Mongrel::HttpParser to an execute method then recapture them as return
values, or something to that effect.
Thoughts? Suggestions? Complete rewrites? I'd appreciate them all.
--
Tony Arcieri
medioh.com