Re: Triple code duplication

On Saturday 24 July 2004 11:50, Karl Vogel wrote:
> While converting kdelibs to a version that explicitly defines what should be 
> exported (using KDE_EXPORT), I noticed that a few things are duplicated.
> 
> For example:
> 
> $ objdump -CT /opt/kde/lib/kde3/kbzip2filter.so |grep init_
> 00001ff0 g    DF .text  00000052  Base        init_kbzip2filter
As wanted.

> $ objdump -CT /opt/kde/lib/kde3/kio_help.so |grep init_
> 0000d900 g    DF .text  00000052  Base        init_kbzip2filter
> 
> $ objdump -CT /opt/kde/lib/kde3/kio_ghelp.so |grep init_
> 0000d900 g    DF .text  00000052  Base        init_kbzip2filter
Side effect, due to what you noticed:
> kdelibs/kdoctools uses kbzip2filter.cpp and compiles it directly into the 
> kio_help.so and kio_ghelp.so shared libs.

> Since this is exactly the same sourcecode as kioslave/bzip2, we now end up 
> with this code duplicated 3 times!
So? For a little bit of unbzip2 code, it's not worth making a shared library, when
every KDE code (other than kio_*help) gets that code dlopened from kbzip2filter.so

If you want to fix this, add a #define INCLUDED_BY_KIO_HELP in kio_help.*
and #ifndef INCLUDED_BY_KIO_HELP around the init_ function.

> I'm also wary as I think this can introduce subtle bugs.. ie if one of those 
> versions is used and then another shared lib is opened containing a version, 
> won't this override the present version ?! What if some state is kept in a 
> global variable that is now overridden by the new version!
I don't follow. The code dlopening kio_help isn't the same as the code 
dlopening kbzip2filter.so, so the above isn't a problem.

-- 
David Faure, [email protected], sponsored by Trolltech to work on KDE,
Konqueror (http://www.konqueror.org), and KOffice (http://www.koffice.org).