[postgis-devel] [postgis-tickets] r15671 - Do not call getPointxx_p on empty or null pointarray

[Sandro Santilli]

On Fri, Sep 08, 2017 at 08:28:12PM -0400, Daniel Baston wrote:
> Should callers be doing this type of checking themselves, instead of
> incurring the penalty on all point access?

Yes, I think it was good for that check to be only activated
on PARANOIA_LEVEL > 1

The change of mine (r15671) is really the outermost caller (from the
liblwgeom point of view) as it's done on a point itself.

Or do you think  lwpoint_getPointXX_p should also not perform
the test ?

I'd be fine either way, as long as we then patch the higher levels
(a unit test, in this case, IIRC)

--strk;

> 
> On Fri, Sep 8, 2017 at 5:46 PM, Sandro Santilli <strk at kbt.io> wrote:
> 
> > Author: strk
> > Date: 2017-09-08 14:46:17 -0700 (Fri, 08 Sep 2017)
> > New Revision: 15671
> >
> > Modified:
> >    trunk/liblwgeom/lwpoint.c
> > Log:
> > Do not call getPointxx_p on empty or null pointarray
> >
> > Add more 0 returns on error
> >
> > Modified: trunk/liblwgeom/lwpoint.c
> > ===================================================================
> > --- trunk/liblwgeom/lwpoint.c   2017-09-08 21:46:10 UTC (rev 15670)
> > +++ trunk/liblwgeom/lwpoint.c   2017-09-08 21:46:17 UTC (rev 15671)
> > @@ -39,24 +39,24 @@
> >  int
> >  lwpoint_getPoint2d_p(const LWPOINT *point, POINT2D *out)
> >  {
> > -       return getPoint2d_p(point->point, 0, out);
> > +       return lwpoint_is_empty(point) ? 0 : getPoint2d_p(point->point, 0,
> > out);
> >  }
> >
> >  /* convenience functions to hide the POINTARRAY */
> >  int
> >  lwpoint_getPoint3dz_p(const LWPOINT *point, POINT3DZ *out)
> >  {
> > -       return getPoint3dz_p(point->point,0,out);
> > +       return lwpoint_is_empty(point) ? 0 : getPoint3dz_p(point->point,0,
> > out);
> >  }
> >  int
> >  lwpoint_getPoint3dm_p(const LWPOINT *point, POINT3DM *out)
> >  {
> > -       return getPoint3dm_p(point->point,0,out);
> > +       return lwpoint_is_empty(point) ? 0 : getPoint3dm_p(point->point,0,
> > out);
> >  }
> >  int
> >  lwpoint_getPoint4d_p(const LWPOINT *point, POINT4D *out)
> >  {
> > -       return getPoint4d_p(point->point,0,out);
> > +       return lwpoint_is_empty(point) ? 0 : getPoint4d_p(point->point,0,
> > out);
> >  }
> >
> >  double
> > @@ -64,7 +64,10 @@
> >  {
> >         POINT4D pt;
> >         if ( lwpoint_is_empty(point) )
> > +       {
> >                 lwerror("lwpoint_get_x called with empty geometry");
> > +               return 0;
> > +       }
> >         getPoint4d_p(point->point, 0, &pt);
> >         return pt.x;
> >  }
> > @@ -74,7 +77,10 @@
> >  {
> >         POINT4D pt;
> >         if ( lwpoint_is_empty(point) )
> > +       {
> >                 lwerror("lwpoint_get_y called with empty geometry");
> > +               return 0;
> > +       }
> >         getPoint4d_p(point->point, 0, &pt);
> >         return pt.y;
> >  }
> > @@ -84,9 +90,15 @@
> >  {
> >         POINT4D pt;
> >         if ( lwpoint_is_empty(point) )
> > +       {
> >                 lwerror("lwpoint_get_z called with empty geometry");
> > +               return 0;
> > +       }
> >         if ( ! FLAGS_GET_Z(point->flags) )
> > +       {
> >                 lwerror("lwpoint_get_z called without z dimension");
> > +               return 0;
> > +       }
> >         getPoint4d_p(point->point, 0, &pt);
> >         return pt.z;
> >  }
> > @@ -96,9 +108,15 @@
> >  {
> >         POINT4D pt;
> >         if ( lwpoint_is_empty(point) )
> > +       {
> >                 lwerror("lwpoint_get_m called with empty geometry");
> > +               return 0;
> > +       }
> >         if ( ! FLAGS_GET_M(point->flags) )
> > +       {
> >                 lwerror("lwpoint_get_m called without m dimension");
> > +               return 0;
> > +       }
> >         getPoint4d_p(point->point, 0, &pt);
> >         return pt.m;
> >  }