This check was only needed because `operator[]` inserts an empty entry
if the variable doesn't exist. Wine also complains when `WINEPREFIX` is
empty, so we should probably not try to have our own behavior here.
This would be useful if you need to do some elaborate namespacing setup
and want all sockets and other temporary files in a single directory
instead of in `${XDG_RUNTIME_DIR:/tmp}`.
This resolves#139.
In some cases we would treat dead processes as not running (we could
also get EAVAIL instead of EINVAL, so it's better to just check the one
thing we should treat as a success instead).
When the user has some sort of hardening going on, we might not be able
to read the Wine process's memory. In that case this check would return
`false` even though the process is still running. To combat this, we
should explicitly check for `EINVAL` which is returned when the file
doesn't exist at all or when it's a broken 'symlink' (even though it
isn't really a symlink).
Apparently this can actually make a difference in some cases, and the
C++ Core Guideliens recommend doing this on all default constructors,
destructors, and all functions that can not throw (and thus also don't
allocate).
We'll periodically copy the scheduling priorities from the host's audio
threads to the Wine plugin host's audio threads. The overhead of doing
this is about 1 microsecond on my system, so doing this every cycle
really adds up. But getting the Unix epoch time and comparing some
timestamps has a neglegible overhead, so this should give you the best
of both worlds.
Next we'll do the same thing for VST3 plugins.
As suggested by @jhernberg
This still seemed to work, but the `sched_setscheduler` would return an
error code when the priority is set to 5 for SCHED_OTHER (which is of
course not a valid value here).
This is a pretty huge change that will be important for being able to
handle nested or mutually recursive `dispatch()` and `audioMaster()`
calls. This sadly all had to be done in a single commit, so here's a
summary:
- `src/common/sockets.h:Sockets` contains all sockets on both the plugin
and the Wine host side, and is used to both listen on and connect to
the sockets.
- Sockets and other temporary files respect `$XDG_RUNTIME_DIR` instead
of being dumped in `/tmp`.
- All sockets now have a unique endpoint in
`/run/user/<uid>/yabridge-<plugin_name>-<random_id>/`. This is
important for when we want to have multiple socket connections for
handling `dispatch()` and `audioMaster()`.
- Because of the above, we no longer clean up the socket endpoint files
after the connection gets established during initialization. Instead
we'll remove the socket base directory when shutting down.
This significantly reduces the latency with no real drawbacks from what
I've noticed. Wineserver is still run using the normal scheduling
policies because from my testing running that with realtime priority
that can actually increase latencies, although doing so will greatly
reduce the variance in processing time.
Robbert van der Helm