Was checking over this old code, and saw a comment calling me out for a lack of documentation.
It might be half a decade late, but better late then never.
Whenever udev_monitor_receive_device() returns a non-null pointer,
the device must be unref'd after use with udev_device_unref().
We previously missed some unref calls for non-evdev devices.
It's not guaranteed that the eventfd is smaller than the monitor fd,
because fds are not always monotonically allocated. To select()
correctly in all cases, use the max between the monitor fd and eventfd.
Axis range was previously calculated as max + abs(min), which relies on the assumption that
min will not exceed 0. For (min, max) values like (0, 255) or (-128, 127), which I assume to
be the most common cases, the range is correctly calculated as 255. However, given (20,
235), the range is erroneously calculated as 255, leading to axis values being normalized
incorrectly.
SDL already handles this case correctly. After changing the range calculation to max - min,
the axis values received from the evdev backend are practically identical to the values
received from the SDL backend.
Ideally Common.h wouldn't be a header in the Common library, and instead be renamed to something else, like PlatformCompatibility.h or something, but even then, there's still some things in the header that don't really fall under that label
This moves the version strings out to their own version header that doesn't dump a bunch of other unrelated things into scope, like what Common.h was doing.
This also places them into the Common namespace, as opposed to letting them sit in the global namespace.
GetName() creates a new evdev device which calls tons of ioctls. But the
main culprit is close() which for input devices appears to be a slow
path in the kernel.
This commit reduces PopulateDevices() by 50% on my laptop, but ~730 ms
is still ridiculously slow for something that isn't needed right away.
