Remove RINGBUF_SEM for RINGBUG_EVENT · a2aa9631Deucе authored
We've never really cared how many times the ring buffer has become empty, how many times data was added to it, or how many times we've been over the highwater mark. These have effectively always been event signalling, with extra hackiness to clear "extra" semaphore posts. This commit removes RINGBUF_SEM entirely, and uses events for everything. There's an empty event (set when the ring buffer is empty), a data event (set when the ring buffer is not empty), and a highwater event (set when the ring buffer has at least highwater mark bytes). A RingBufWrite() will set data and highwater events if applicable, and clear the empty event. A RingBufRead() will set empty event and clear data and highwater events if applicable. RingBufReInit() will now set the empty event, and clear the data and highwater events. These are the only actions the RingBuf API will perform on the events, it does *not* clear the highwater event on a RingBufWrite() if the buffer does not have enough bytes in it for example, this will *only* be done by RingBufRead() or RingBufReInit(). This allows consumers to force specific behaviours (such as forcing the highwater event on shutdown to prevent waiting for it). Since the current code was able to deal with the semaphores having arbitrarily high counts, the existing code shouldn't have any issue with this. For things that want to shut something down, we're now setting both the data and highwater events to ensure it doesn't wait for a timeout (even for things that don't use highwater like the inbuf). The RingBuffer API should grow a thing to do this (RingBufferFlush perhaps?) rather than the consumers poking into the innards arbitrarily. Tested on the webserver and RLogin server and seems to be working great. sexyz builds. It seems there's some Windows thing that uses the ringbuffer sem for something, but I couldn't figure out what... updated the build file, but no clue if that's broken or not now... I'm sure DigitalMan will be happy to fix it if CI doesn't catch it. ;) This should allow the console object to grow a "flush" method that will set the highwater and data events.