Mapserver compilation flags should be added to the SWIG command line

Steve Lime Steve.Lime at DNR.STATE.MN.US
Thu Aug 31 12:58:57 EDT 2006 

I'm ok with the always having the geometry there and then hiding in any
case.

Regarding the defines with SWIG. I guess it boils down to whether or
not you
want:

  1) a consistent interface regardless of build environment, that is,
something like $shape->interects(...) always exists, but will throw an
error if the right supporting library isn't available

  2) an inconsistent interface that has different syntax depending on
build environment

Option 1 forces folks to practice good programming and actually check
returned values, while option 2 is far less subtle. You'll know right
away if something isn't available. Not sure which I prefer.

Steve

>>> Tamas Szekeres <szekerest at GMAIL.COM> 8/31/2006 6:49:48 AM >>>
Umberto,

At this point I cannot see considerable reason not to apply those
changes. But I am still sure that adding the defines to SWIG and the
mapscript C compilation ensures that the SWIG interface will be
generated correctly and no runtime problems will happen (dedicated to
this issue).

But again, I am +1 adding void* geometry to shapeObj regardless of the
USE_GEOS setting and hiding this member from the SWIG interface.

Tamas



2006/8/31, Umberto Nicoletti <umberto.nicoletti at gmail.com>:
> Tamas,
> I have reviewed all the .h files included in mapscript.i and I have
> found that there are only a few unsafe usages of defines (and they
> refer to the usual suspects, that is z/m members for points and
geos).
>
> In mapprimitive.h
>
> line 74 (Definitely UNSAFE!!)
> #ifdef USE_POINT_Z_M
>   double z;
>   double m;
> #endif
>
> line 100 (UNSAFE, but fixable):
> #ifdef USE_GEOS
>   void *geometry;
> #endif
>
> Other suspicious usages could be in mapows.h, but at this time I am
> not sure whether they are actually posing a problem.
>
> I don't see an easy solution to the z/m defines, but I attach a
patch
> that removes the need for #ifdef USE_GEOS in mapprimitive.h. I have
> made a couple of tests and it seems ok to me, but I want your
valuable
> feedback and Steve's approval before I commit it.
>
> Umberto
>
> On 8/31/06, Tamas Szekeres <szekerest at gmail.com> wrote:
> > Hi Umberto,
> >
> > How your proposal will prevent from the need of settings the
defines to SWIG?
> > We have ifdefs in some of the headers (eg. in map.h) will continue
to
> > affect the interface generation.
> >
> > Tamas
> >
> >
> >
> > 2006/8/31, Umberto Nicoletti <umberto.nicoletti at gmail.com>:
> > > Hi Tamas,
> > >
> > > On 8/30/06, Tamas Szekeres <szekerest at gmail.com> wrote:
> > > > Umberto,
> > > >
> > > > I guess your proposal was to replace the affected functions
from the
> > > > interface files to the core mapserver code, correct me if I am
wrong.
> > >
> > > You are right.
> > >
> > > > But I still can't understand what's the problem with adding
the
> > > > preprocessor defines to the SWIG command line. It requires to
change
> > > > only a line in the makefile.
> > >
> > > Only Java and c# have makefiles. Perl, python, tcl don't.
> > > Keeping preprocessor defines out of the interface files was a
design
> > > decision taken a long time ago and (almost) always enforced. In
fact
> > > there aren't other defines in all the rest of the swig interface
> > > files.
> > >
> > > Umberto
> > >
> > > >
> > > > Tamas
> > > >
> > > >
> > > >
> > > > 2006/8/30, Umberto Nicoletti <umberto.nicoletti at gmail.com>:
> > > > > Hi Steve,
> > > > > While doing the usual house keeping before 4.10 gets out I
have looked
> > > > > at the source of the swig interface files and found that they
contain
> > > > > preprocessor defines (#ifdef USE_GEOS for example).
> > > > > Most of the mapscript laguages will ignore these defines
because swig
> > > > > is not passed the list of options built by configure. Java
mapscript
> > > > > used to pass the list to swig, but this feature was removed a
long
> > > > > time ago because Sean opted for removing the preprocessor
defines from
> > > > > the swig interface files to keep them tidier.
> > > > > C# mapscript at this point is the only laguage still passing
defines to swig.
> > > > > Perl, Ruby and Python invoke swig without passing the
defines; also,
> > > > > in the case of Perl and Python swig must be run manually by
the user
> > > > > (by typing the right command in the shell).
> > > > >
> > > > > Now since most mapscript will ignore those preprocessor
defines we are
> > > > > facing a potentially critical issue and, in the case of
GEOS,
> > > > > mapscript won't use some GEOS functions.
> > > > > Other possible errors could be memory errors due to the use
of non
> > > > > initialized variables (this is the case of POINT_Z_M).
> > > > >
> > > > > I have reviewed the swig interface files and found these
possibly
> > > > > harmful defines:
> > > > >
> > > > > swiginc/image.i:#if GD2_VERS > 1
> > > > >
> > > > > Not sure about this one, maybe it is right. Dunno where
GD2_VERS is defined.
> > > > >
> > > > > swiginc/image.i:#ifdef USE_GD_GIF
> > > > > swiginc/image.i:#ifdef USE_GD_PNG
> > > > > swiginc/image.i:#ifdef USE_GD_JPEG
> > > > > swiginc/image.i:#ifdef USE_GD_WBMP
> > > > >
> > > > > These were added by Sean in July 04 and should be removed, I
guess.
> > > > > They only affect TCL.
> > > > >
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > >
> > > > > These are *rarely* used and they are not a real problem, at
least for
> > > > > 4.10. If used they crash Java mapscript for sure.
> > > > >
> > > > > swiginc/shape.i:#ifdef USE_GEOS
> > > > > swiginc/shape.i:#ifdef USE_GEOS
> > > > >
> > > > > These were added by sdlime on his lates rework of geos code
this june.
> > > > > They should be moved out of the swig interface file into the
c code of mapserver
> > > > >
> > > > > I hope I made myself clear,
> > > > > Umberto
> > > > >
> > > > > On 8/28/06, Steve Lime <Steve.Lime at dnr.state.mn.us> wrote:
> > > > > > Confused, what's the desired fix?
> > > > > >
> > > > > > >>> Umberto Nicoletti <umberto.nicoletti at GMAIL.COM>
8/28/2006 10:47:08
> > > > > > AM >>>
> > > > > > I have posted a similar mail today (search for Defines in
swig
> > > > > > interface files in the subject) . Tamas, sorry for the
double posting,
> > > > > > I missed this one.
> > > > > >
> > > > > > I appear to recall that it was once agreed that swig
interface files
> > > > > > should not have defines in them, but I at the moment the
only
> > > > > > reference I found is here:
> > > > > >
> > > > > > http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=895#c2 
> > > > > > (end of first para)
> > > > > >
> > > > > > Sean Gillies probably knows better.
> > > > > >
> > > > > > At this point C# is the only language that has 100%
correct
> > > > > > compilation today. Java mapscript had the flags passed to
swig, but
> > > > > > they were removed a long time ago.
> > > > > > Other laguages like ruby and python require the user to
generate the
> > > > > > interface by running swig by hand. This makes it much
difficult to
> > > > > > pass defines to swig as the user should have to copy them
from the
> > > > > > Makefile or alternatively we should provide and mantain
Makefiles for
> > > > > > all mapscripts.
> > > > > >
> > > > > > This is the list of defines (still) in the swig interface
files:
> > > > > >
> > > > > > swiginc/image.i:#if GD2_VERS > 1
> > > > > >
> > > > > > Not sure about this one, maybe it is right.....
> > > > > >
> > > > > > swiginc/image.i:#ifdef USE_GD_GIF
> > > > > > swiginc/image.i:#ifdef USE_GD_PNG
> > > > > > swiginc/image.i:#ifdef USE_GD_JPEG
> > > > > > swiginc/image.i:#ifdef USE_GD_WBMP
> > > > > >
> > > > > > These were added by Sean in July 04.
> > > > > >
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > > swiginc/point.i:#ifdef USE_POINT_Z_M
> > > > > >
> > > > > > These are rarely used and they are not a real problem, at
least for
> > > > > > 4.10
> > > > > >
> > > > > > swiginc/shape.i:#ifdef USE_GEOS
> > > > > > swiginc/shape.i:#ifdef USE_GEOS
> > > > > >
> > > > > > These were added by sdlime on his lates rework of geos code
this june.
> > > > > >
> > > > > > I can try to take care of the defines in image.i and maybe
steve of
> > > > > > those in shape.i, but I dunno if I'm going or if we should
do it for
> > > > > > for 4.10?
> > > > > >
> > > > > > Umberto
> > > > > >
> > > > > >
> > > > > > On 8/28/06, Daniel Morissette <dmorissette at mapgears.com>
wrote:
> > > > > > > Tamas Szekeres wrote:
> > > > > > > > Folks,
> > > > > > > >
> > > > > > > > Currently most of the SWIG bindings does not add
mapserver
> > > > > > compilation
> > > > > > > > flags to the
> > > > > > > > SWIG command line and therefore the interface might not
be
> > > > > > generated
> > > > > > > > properly.
> > > > > > > > For example missing -DUSE_POINT_Z_M will prevent from
generating z
> > > > > > and m
> > > > > > > > members
> > > > > > > > for pointObj etc.
> > > > > > > >
> > > > > > > > I've added a bug for this issue:
> > > > > > > > http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1881

> > > > > > > >
> > > > > > > > And fixed for C#
> > > > > > > >
> > > > > > >
> > > > > > > Does something need to be done for this for the other
wrappers?
> > > > > > There
> > > > > > > used to be a 'mapscriptvars' file with all the compile
flags used by
> > > > > > the
> > > > > > > Perl Makefile. Is this not used by the other bindings?
> > > > > > >
> > > > > > > Daniel
> > > > > > > --
> > > > > > > Daniel Morissette
> > > > > > > http://www.mapgears.com/ 
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
>
>

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