[Xastir] [BSD-Ham] Xastir Tiger map caching in FreeBSD.

[Tom Russo]

On Mon, May 27, 2024 at 12:35:44PM +1000, we recorded a bogon-computron collision of the <carl at stagecraft.cx> flavor, containing:
> Hi Everyone,
> One of the port system maintainers of FreeBSD has proposed the removal of the dependancy on libdb5 (Berkeley DB 5) from Xastir as libdb5 is deprecated and no longer maintained.  Not being in the US I’ve never used Tiger maps and I don't really know if removing the Tiger map caching capability will make them unusable, however given the availability of other maps and the fact libdb5 is no longer being maintained I’ve approved the change.

I'm one of the folks who curates the Xastir repository at Github and 
"maintains" the software there .  I also use Xastir on FreeBSD though I do not 
use the port at all and build it myself all the time.

The libdb5 capability in Xastir is not solely for Tiger maps, even though it 
is likely that the documentation makes wild, outdated assertions to that
effect.

Tiger map servers themselves are long gone and all Tiger-specific map code
removed from Xastir back in 2019.  So DB5 support has nothing to do with
Tiger maps in the US anymore, even though that was the reason it was  
initially implemented.

In fact, BDB5 is used for general caching of online maps *other* than tiled 
map sets like OpenStreetMaps (a completely different technique is used for 
downloading and caching of OSM tiles).  WMS map servers would all make use of 
caching to prevent unnecessary re-download of map images.  WMS servers for 
online maps are still plentiful both in and out of the US, and in fact just 
last year we helped a user in Finland get Xastir working with a WMS server 
from the Finish Land Survey (c.f. https://github.com/Xastir/Xastir/discussions/211).

Building Xastir without Berkeley DB support would mean that all users of
WMS servers would be downloading new images with every map pan or zoom 
operation because downloaded images would no longer be cached.  They would
still be usable, but would be slow and wasteful.

Nobody has gone to through the exercise of trying to adapt the DB5 code in 
Xastir to use a maintained version of Berkeley DB.  I don't even know how 
different db18 is from db5 at this point.  At a minimum, even if the API 
hasn't changed significantly, the hamfisted technique used in Xastir's 
configure script to find DB headers and libraries would need modification.

I have opened an issue on Xastir's issue tracker to see if we can get a 
volunteer to look into updating the code to make use of a supported version of 
Berkeley DB since DB5 is so ancient.   (https://github.com/Xastir/Xastir/issues/217)

I am not, however, in a position to volunteer to take over maintaining the
Xastir port in the FreeBSD ports tree, though I'm perfectly willing to submit
PRs with patches from time to time when we release new versions of the code.  

-- 
Tom Russo    KM5VY
Tijeras, NM  

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