car/interface: retrieve car brand list from car.values.BRANDS

[deanlee]

Cache the list of car brands as CAR_BRANDS, improving performance by eliminating redundant directory scans on subsequent function calls.

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[sshane]

Can we not use car.values.BRANDS?

[deanlee]

I'm not quit sure how to correctly retrieve the brand name from car.values.BRANDS. Would it be something like this?

import inspect
...
for brand in BRANDS:
    try:
      brand_name = inspect.getmodule(brand).__name__.split('.')[-2]
      brand_values = __import__(f'openpilot.selfdrive.car.{brand_name}.{INTERFACE_ATTR_FILE.get(attr, "values")}', fromlist=[attr])
      ...

but the inspect.getmodule is expensive, slower compared to simple I/O operations.

[sshane]

How about __module__?

[deanlee]

Ahhhh, got it!

[adeebshihadeh]

I think we just want to get rid of the dynamic importing. Want to open a PR for that?