Geometry.dup should clone the geometry

Question

Geometry.dup should clone the geometry

dazuma opened this issue 13 years ago · comments

0.0.1.beta2

Geometry.clone performs a GEOSGeom_clone_r. Geometry.dup does not. As a result, if you dup a geometry (a shallow copy by default), the two copies share the same autopointer. Now if one of the copies gets collected, the autopointer will get released, which throws the other into a bad state. I suggest dup should also perform GEOSGeom_clone_r.

J · Answer 1 · Wed May 18 2011 12:16:45 GMT+0800 (China Standard Time)

I've written a patch that implements initialize_copy methods on Geometry and CoordinateSequence that I believe should take care of these situations rather than relying on an actual clone method, which was pretty bad form on my part to begin with.

The remaining classes (BufferParams, PreparedGeometry and STRTree) don't have cloning functions in the GEOS CAPI... what would you think about disabling those methods for those classes by raising exceptions for those classes on calls to clone and dup? BufferParams doesn't really need to be instantiated so much anyways as it really just acts as a wrapper for options, PreparedGeometry can't be instantiated directly anyways, and STRTree, well... that one I could clone by hand I suppose.

I've pushed a fix in 13889a5 if you'd like to try things out. Cheers.

Daniel Azuma · Answer 2 · Wed May 18 2011 22:45:51 GMT+0800 (China Standard Time)

Thanks. The patch looks good so far on my end. I agree on Buffer Params, PreparedGeometry, and STRTree: they can raise exceptions. We just need something better than segfaults. :-)

J · Answer 3 · Sat Oct 22 2011 04:17:29 GMT+0800 (China Standard Time)

Think we've closed the book on this one, so closing.