[Community] Shapely, ctypes and finding geos_c

[Sean Gillies]

Christopher Barker wrote:
> Sean Gillies wrote:
>> Christopher Barker wrote:
>>>      if lib is None:
>>>          ## try a few more locations
>>>          ## This, or course, could be a lot smarter!
>>>          lib_paths = 
>>> ["/Library/Frameworks/GEOS.framework/Versions/Current/unix/lib/libgeos_c.dylib",# 
>>> The Framework build from Kyng Chaos:
>>>          ]
>>>          for path in lib_paths:
>>>              if os.path.exists(path):
>>>                  lib = path
>>>                  break
>>>          else:
>>>              raise Exception("Could not find geos_c library")
> 
>> The only problem I see with the patch is that the framework name/path
>> looks arbitrary to me. But then I don't know much about the Mac lib
>> frameworks.
> 
> Well, it's not entirely arbitrary -- Frameworks all go in either:
> 
> /Library/Frameworks/ (for user-installed stuff)
> or
> /System/Frameworks/ (for Apple-installed stuff)
> 
> within the Framework, the "Version/Current is standard. however, the 
> name GEOS.Framework may not be -- it's hard to be too standard if the 
> Framework isn't provided by apple, or part of the official build of the 
> lib -- I don't know if William has contributed his Framework building 
> code to the geos project.
> 
> There is also this complications -- the "Apple-y" way to do it is to 
> have the actual shared lib in:
> 
> GEOS.framework/Versions/Current.GEOS  (no extension)
> 
> The "unix/lib/libgeos_c.dylib" part is William's trick for making the 
> Framework look like a more traditional unix setup so other libs that 
> don't understand frameworks can build against it. As I look, I see that 
> unix/lib/libgeos_c.dylib is actually a link back to "GEOS" anyway, so 
> the patch should be:
> 
> elif sys.platform == 'darwin':
>      lib = find_library('geos_c')
>      if lib is None:
>          ## try a few more locations
>          ## This, or course, could be a lot smarter!
>          lib_paths = 
> ["/Library/Frameworks/GEOS.framework/Versions/Current/GEOS",# The 
> Framework build from Kyng Chaos:
>          ]
>          for path in lib_paths:
>              if os.path.exists(path):
>                  lib = path
>                  break
>          else:
>              raise Exception("Could not find geos_c library")
>      lgeos = CDLL(lib)
>      free = CDLL(find_library('libc')).free
> else:
> 
> That's about as "standard" as it will ever get. And William's stuff is 
> getting pretty wide use. The other open question is if we want to point 
> to "Current" or specifacally to 3.0 (which is the same on my system, but 
> may not be in the future.)
> 
> As I mentioned, there is also macports and fink, that put these things 
> it yet another place. The idea behind what I've done is that others can 
> contribute their paths, and eventually, we may find most of them 
> automagically.
> 
> This is ugly, but I don't know how else to do it. They call it dll hell 
> for a reason!
> 
> -Chris

I'm coordinating with Mr. geo-fink, Kurt Schwehr, right now. It seems to
do the normal GNU thing, much like you'd get with a configure; make;
make install.

I made a new ticket for the above

http://trac.gispython.org/projects/PCL/ticket/154

and patched it in r1048. Feel like giving it a test drive?

svn co http://svn.gispython.org/svn/gispy/Shapely/trunk Shapely

With no other bug to address right now, that is poised to become Shapely
1.0.1. Thanks for the patch,

Sean