[Toybox] Pending fiddliness

[Terrel Shumway]

The same issue arises with the ps utils: pgrep pkil and ps should
share a lot of code that nothing else would use.

On Wed, Jun 19, 2013 at 6:51 PM, Rob Landley <rob at landley.net> wrote:
> I've been holding off on "mv" forever, even though it's a commonly used
> command that I've got the infrastructure for (it's a simpler version of cp),
> because I haven't figured out how to get the code sharing quite right yet.
>
> I want to share infrastructure between "mv" an option of "cp". The main()
> function is mostly the same, for example. And if mv is used across
> partitions, it falls back to a combination of cp and rm.
>
> I could move cp code out into lib/ but that gets built for every command,
> and makes reading the logic of "cp" itself more convoluted. If only two
> commands are sharing it, having the logic way out of line is not ideal. The
> other way of doing this is to add an OLDTOY() macro to cp.c adding mv as an
> alias with different behavior. The problem here is option flags.
>
> The option flag infrastructure defines FLAGS_X for the current command.
> That's the main reason #define FOR_mv is needed up at the top, I could never
> work out how to autoselect that from __FILE__ or similar. (There's no strcmp
> in #if tests.)
>
> So commands that share a .c file can't have their own FLAG_ macros. I could
> do the flag math by hand (the flags run right to left to make that easier,
> the same order as the binary bits when written out, abcd a=8 b=4 c=2 d=1),
> but I've removed the need for that from the rest of the code and doing it
> here seems ugly. (And brittle if I change the flags and have to redo them by
> hand...)
>
> Maybe I'll do them by hand for right now and try to come up with a cleaner
> way later...
>
> Or I could be _really_ subtle and only use a subset of the flags that mv
> alreay does (POSIX only specifies -f and -i, the rest are optional), and
> keep them in the same order so the FLAG macros work out right. But I
> _really_ shouldn't name the variable that indicates we were called as move
> instead of cp TT.fezzig.
>
>   http://www.girlgeniusonline.com/comic.php?date=20100609
>
> (Hy iz not done mit tryink de sottle!)
>
> Rob
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