Squawks of the Parrot

Tornado 0.05

So, I've released Tornado 0.05. This release, in addition to a few bug fixes, now properly handles callbacks into the embedding application. The perl module's been rev'd to handle this as well. This means you can call tornado code from your perl, you can get results back from that tornado code, and you can register perl subs as callbacks for that tornado code. Nifty!

There's one big limitation, which I'm unhappy with. For reasons that annoy me, when waiting on a handle for results, only callbacks posted in the function the handle represents will be processed. I'd hoped to have it so that callbacks from any function in that particular instance of Tornado would be processed, but I wasn't thinking clearly and put together a design that required waiting on multiple condition variables simultaneously, which just doesn't work with pthreads.

Of course, now after spending a few hours hacking that out so that each handle was independent, I realized I could have them all coordinate on a single instance-wide condition variable without much trouble. I'd rejected it for performance reasons -- it'd mean all the waiting threads would wake up and have to check to see if their individual wait condition was satisfied -- but on further reflection that was kind of silly, as there's unlikely to be many host threads waiting on the instance mutex at any one time, so the CPU time spent waking them all up and having them go back to sleep just isn't likely to be a big deal.

Anyway, this works, which is cool. Next step is either to get the Windows build working (I need to get Win-specific thread stuff in) or to get the threads-spawning-threads and messaging code in. Not sure which. I think I ought to get win-threads working first, but message-passing and thread-spawning is a lot more interesting.