Re: [Gpsbabel-code] instance data & r/w capabilities

[Robert L. <rob...@us...>]

Ron Parker wrote:

> xcsv actually supports tracks and routes, more or less, in the sense that
> if you manually specify -t it'll write the trackpoints in the specified

Yep.  We really do need to push this into the style formats, but I
weenied out:

$ grep -i ff_cap xcsv.c
    FF_CAP_RW_WPT, /* This is a bit of a lie for now... */

> format instead of writing the waypoints.  I think it wouldn't hurt to have
> flags that indicate whether the format can handle combinations of
> waypoint/track/route (as GPX does) and whether it can automatically detect
> what it's dealing with or it has to be told.

I've been trying to move everything except the serial formats to the
auto-detection scheme, but we do still have a number of corner cases.

> initialize it to?  For that matter, rd_init and wr_init could handle
> the initialization of things that are confined to a single -f or -F
> operation, provided you just pass in a void ** out-var to rd_init and
> then pass the resulting value to read and rd_deinit (ditto for wr*)

That's the other variation I considered, but I was thinking that forcing
everything to be dynamically allocated I could be heavy handed and
"force" modules to the new scheme just by looking at the size of their
data.

I could go either way.

> Note too that several of those static globals are things that are set up
> when -i or -o is invoked, so initializing them at -f or -F time (when
> rd_init or wr_init is called) would be Bad.  We should probably also have
> a function that gets called at -i or -o time, perhaps as part of find_vec.

That's an interesting point.  Sometimes that's intentional but often
times it's a bug.

> find_vec already defaults all args, but it doesn't handle any variables
> that are set up as a result of those args.  At the moment, I think that
> falls to rd_init or wr_init, but that has never seemed quite right to me
> (even though I can't think of an example of such a dependent variable

I've never really been happy about that, either.

Maybe it's not worth rocking this particular boat.  It boils down to a
lot of busy work just to try to design a (relatively small) set of bugs
away.

RJL