[Libwebsockets] Recent buggy changes

Andy Green andy.green at linaro.org
Wed May 6 02:20:27 CEST 2015


On 6 May 2015 07:40, "Andrey Pokrovskiy" <wonder.mice at gmail.com> wrote:
>
> You have to ALWAYS include lws_config.h in the beginning of
> libwebsockets.h because that's how libwebsockets.h knows about options
> with which the library was compiled. If you look into libwebsockets.h
> you will see it uses defines from lws_config.h, such as
> LWS_NO_EXTENSIONS, LWS_OPENSSL_SUPPORT, LWS_USE_LIBEV.
>
> Before that patch it was basically broken and to use it correctly you
> have to define CMAKE_BUILD in your project manually to workaround
> that.
>
> But I agree that it's completely inappropriate to have such generic
> defines in library public header. I even added a comment for that:
>
> /* That's a bad idea since it will leak all internal defines outside */
> #include "lws_config.h"

Yeah.  It's better if you don't say, "it's a bad idea to stick my hand in
the fire" and then stick your hand in the fire as if that absolved anyone
from feeling the pain though.

> I suppose the right solution is to split lws_config.h on two - public
> (LWS_xxx things) and private (all other things). Or just prefix
> everything with "LWS_". But any solution probably will have some
> "compatibility" issues, so chances are things will remain the way they
> are.

I think the root cause of the current situation is I accepted some
patchbombs I should have asked to be split up.

> On Tue, May 5, 2015 at 1:19 PM, Roger Light <andy.green at linaro.org> wrote:
> > Hi there,
> >
> > I believe that a recent changeset introduced some undesirable changes
> > to libwebsockets. I'm not sure what the best solution is, hence this
> > email.
> >
> > The change is:
> >
> >
https://github.com/warmcat/libwebsockets/commit/04da2ccd1e8c5b582c4e2a77ee53f929ae8f22a0
> >
> > "Always include lws_config.h since now we have only CMake build"
> >
> > This means that libwebsockets.h always #includes lws_config.h, whereas
> > before it was only included if CMAKE_BUILD was defined - this means
> > only when the library itself was being built in practice. From what I
> > can see, lws_config.h includes a mix of information that is useful to
> > people using lws - such as whether it was compiled with cyassl support
> > - and lots of things that aren't really of any interest.
> >
> > One of these things is the "#define VERSION" macro. This means that
> > lws is claiming ownership of the VERSION macro, which seems a bit
> > impolite for a library to do :) The shame of it is that the changeset
> > acknowledges that the change is going to cause problems.
> >
> > I think that these is a lot of leftover cruft from autoconf days, but
> > I don't know everything that can be cut. I think that if it is
> > possible to have lws_config.h for public information about the lws
> > build, and lws_config_private.h for things that lws needs for its own
> > build that would be a reasonable solution.

It sounds good to me if someone will implement it.  Otherwise I think we
were better off how it was.

I assume user code prior to this with CMAKE_BUILD will just continue to
work fine.

-Andy

> > Any thoughts?
> >
> > Cheers,
> >
> > Roger
> > _______________________________________________
> > Libwebsockets mailing list
> > Libwebsockets at ml.libwebsockets.org
> > http://ml.libwebsockets.org/mailman/listinfo/libwebsockets
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