[geos-devel] Fwd: Prepared Geometry

[Paul Ramsey]

Hartmut,

Just FYI, in case you didn't know, GEOS comes by it's Java'ish
anti-pattern "honestly",

http://lin-ear-th-inking.blogspot.com/2007/06/history-of-jts-and-geos.html

Thanks again for the patch. Compared to the postgis code calling it,
it's a thing of beauty :)

P.

On Thu, Oct 9, 2008 at 1:48 PM, Hartmut Kaiser <hartmut.kaiser at gmail.com> wrote:
> Martin,
>
>> I have to disagree with Hartmut's complaint.  The SegmentString class
>> is
>> intended to be an adapter class, which wraps a data structure
>> (Coordinate sequence) owned by some client to allow it to be processed
>> by the noding logic.  Under this pattern, the SegmentString class
>> definitely should  *not* be freeing the memory for the wrapped sequence
>> - that is the responsibility of the client.
>
> Well, that's a decision of the people around the GEOS project, not mine. I
> just fixed some nasty memleaks which wouldn't have been there if some more
> coherent memory (and encapsulation) strategy had been used. I'm sure there
> was a reason for that. But please don't jump on me, I'm only saying that I
> would have done it differently.
>
>> I can't comment on "writing C++ like Java", but obviously C++ requires
>> more knowledge of the usage patterns of memory resources than Java
>> does.  That's why Java is easier to write  8^)
>
> Come on, this is your personal opinion. And please, there is no need to
> start a religious war here.
> I was intentionally very cautious while writing my remark in the first
> place.
>
> Regards Hartmut
>
>>
>> Paul Ramsey wrote:
>> > Another quarter heard from. I have applied this "ugly" patch
>> > nonetheless, since it removes my leak in PostGIS.
>> >
>> > P
>> >
>> >
>> > ---------- Forwarded message ----------
>> > From: Hartmut Kaiser <hartmut.kaiser at gmail.com>
>> > Date: Thu, Oct 9, 2008 at 6:55 AM
>> > Subject: RE: Prepared Geometry
>> > To: Paul Ramsey <pramsey at cleverelephant.ca>
>> >
>> >
>> > Paul,
>> >
>> >
>> >> Could you try big against small1 and small2?
>> >>
>> >
>> > Patch attached. But frankly, I don't like the solution (even if it
>> adopted
>> > the way it's currently handled all over the place in GEOS).
>> >
>> > The way the SegmentString class is written and used requires the user
>> of the
>> > an instance of SegmentString to take care of the deletion of the
>> embedded
>> > point array, for instance:
>> >
>> >    for ( size_t i = 0, ni = lineSegStr.size(); i < ni; i++ )
>> >    {
>> >        delete lineSegStr[ i ]->getCoordinates();    // <-- here
>> >        delete lineSegStr[ i ];
>> >    }
>> >
>> > Which is just wrong, because this could be done in a better way if
>> > SegmentString was taking care of this in the destructor. I tried to
>> fix GEOS
>> > (and the tests) in this direction, but apparently the buffers stored
>> in the
>> > SegmentString are shared in between different higher level structures
>> in
>> > addition, which makes it impossible (at least currently for me) to
>> fix that
>> > without introducing some kind of smart pointers (or investing a
>> really large
>> > amount of time, which I don't have) ...
>> >
>> > For this reason I fixed this memory leak the straightforward (and
>> ugly) way.
>> > I'm sure there are more similar bugs to recover, though :-P
>> >
>> > Regards Hartmut
>> >
>> > PS: As impressive GEOS is it convinces me once more that it's not a
>> good
>> > idea to write C++ in a way similar to Java, especially if no special
>> means
>> > of memory management (i.e. smart ptrs) are introduced.
>> >
>> >
>> >
>> >> Thanks!
>> >>
>> >> Paul
>> >>
>> >> On Wed, Oct 8, 2008 at 1:54 PM, Hartmut Kaiser
>> >> <hartmut.kaiser at gmail.com> wrote:
>> >>
>> >>> Paul,
>> >>>
>> >>>
>> >>>> The reason I ask is because while contains and covers appear leak
>> >>>> free, intersects seems to be leaking. I'm pretty sure it's not on
>> >>>>
>> >> the
>> >>
>> >>>> PostGIS side (I think).
>> >>>>
>> >>>> P.
>> >>>>
>> >>>> On Wed, Oct 8, 2008 at 12:25 PM, Paul Ramsey
>> >>>> <pramsey at cleverelephant.ca> wrote:
>> >>>>
>> >>>>> Hartmut,
>> >>>>>
>> >>>>> When you tested for leaks, did you test prepared contains,
>> >>>>>
>> >>>> intersects,
>> >>>>
>> >>>>> covers, coversproperly? Or just one of them?
>> >>>>>
>> >>> I was using the test program as attached to the ticket (which AFAIR
>> >>> calls all of the topological attribute functions). This test
>> program
>> >>> was leak free for me. But I tried the geometries as attached to the
>> >>> ticket only either, so your leaks might show themselves with
>> certain
>> >>>
>> >> geometries only.
>> >>
>> >>> Regards Hartmut
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> -------------------------------------------------------------------
>> -----
>> >>>
>> >>> _______________________________________________
>> >>> geos-devel mailing list
>> >>> geos-devel at lists.osgeo.org
>> >>> http://lists.osgeo.org/mailman/listinfo/geos-devel
>>
>> --
>> Martin Davis
>> Senior Technical Architect
>> Refractions Research, Inc.
>> (250) 383-3022
>>
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>
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