Small problem with PolkitQt

[Dario Freddi]

Hello back,

2010/1/11 Alexander Neundorf <neundorf at kde.org>
>
> On Sunday 10 January 2010, Dario Freddi wrote:
> > Sorry for the late answer, troubled life is back.
> >
> > On Wednesday 30 December 2009 21:38:12 Alexander Neundorf wrote:
> > [..]
> >
> > > In general determining install locations are the responsibility of the
> > >  project which is being built. I mean, if I chose to install something to
> > >  $HOME/inst it shouldn't matter where PolkitQt is installed.
> > >
> > > What we do for the other install dirs like BIN_INSTALL_DIR etc. in
> > > kdelibs is the following:
> > > if the variable (e.g. KDE4_AUTH_POLICY_FILES_INSTALL_DIR) has not been
> > > explicitely set, and if the current CMAKE_INSTALL_PREFIX is the same as
> > > the kdelibs install prefix, then we reuse the variable (e.g.
> > > KDE4_AUTH_POLICY_FILES_INSTALL_DIR) from kdelibs.
> > >
> > > Look for the macro _SET_FANCY() in
> > > kdelibs/cmake/modules/FindKDE4Internal.cmake.
> > >
> > > Does this do what you want ?
> >
> > Unfortunately not. The problem here is that we really want to store some
> > data: KAuth is backend based, and we have no knowledge at build time
> > (outside KDELibs) of which backend was built, hence how to handle it.
> >
> > This is probably a reason why I'd put stuff in
> > CreateKDELibsDependencies.cmake. I'd add two variables: one,
> > KDE4_AUTH_BACKEND_NAME, carrying the name of the chosen backend, and one,
> > KDE4_AUTH_POLICY_FILES_INSTALL_DIR carrying the location of the policy
> > files install dir, if any (which is required unless we decide to install
> > findpolkitqt*.cmake).
> >
> > Now, the logic for selecting the backend name is
> > kdecore/auth/ConfigureChecks.cmake, where the KAUTH_BACKEND variable is
> > set. Once that is done, finding out the value of
> > KDE4_AUTH_POLICY_FILES_INSTALL_DIR is a breeze. The only problem I see is
> > that putting straight into
> > CreateKDELibsDependenciesFile.cmake set(KDE4_AUTH_BACKEND_NAME
> > ${KAUTH_BACKEND}) fairly doesn't work.
>
> I guess KAUTH_BACKEND is empty for you ?
> There are I think three way you can get values from child directories up their
> parent directories:
>
> 1) put them in the cache.
> This is "almost" done for KAUTH_BACKEND.
> There is the following code in kdecore/auth/ConfigureChecks.cmake:
>
> set(KAUTH_BACKEND "" CACHE STRING "Specifies the KAuth ...")
> ...
>       if (POLKITQT_FOUND)
>            set (KAUTH_BACKEND "PolkitQt")
> ...
>
>
> The first line puts KAUTH_BACKEND in the cache if it's not already there. So
> you can access this value ("") from the toplevel.
> Then, later on, there are several set(KAUTH_BACKEND ...) calls without
> the "CACHE" argument. This means they set the non-cache variable
> KAUTH_BACKEND, which hides the one from the cache, but which doesn't write
> the new value into the cache.
> To actually get this value into the cache, you need to use the FORCE argument
> for set:
> set( ... CACHE ... FORCE)
> This will write the value into the cache no matter what's already there in the
> cache.
> I guess this is what you want to do.

It is. The attached patch does exactly this, and it works. It feels to
me a bit weirdo, though, that I have to set the docstring each and
every time. Maybe I am missing something?
Also, I changed the name of KAUTH_BACKEND into KDE4_AUTH_BACKEND_NAME
for consistency. I'll write somewhere about the change as well.

>
>
> [snip]
>
> And I still think the install dir should be handled the same way the other
> install dirs are handled, i.e. it should take the same value as kdelibs if it
> is installed to the same prefix, it should be settable via the cache, and I
> wouldn't mind if it defaults to some other location if the
> CMAKE_INSTALL_PREFIX is different from the kdelibs location.


It actually should be already so: as you can see from the patch, the
locations are based upon CMAKE_INSTALL_PREFIX (even if this might lead
to utter fails, which are however decently reported at build time),
and added to the cache.

>
>
> Alex
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