[Gnu-arch-users] Efficiently find out if <file> is source or not

[Stefan Monnier]

Let's say I'm given a file name and I need to figure out whether it's
considered as a source file by Arch or not.

How can I do that efficiently [ i.e. in constant time ] ?
Ideally this should work even if tla is not installed.
The only way I could come up with is to do something akin to:

    tla inventory -s `dirname $file` | grep $file

but this can take a long time.


        Stefan