[CMake] Support for multiple components in cpack

[Kishore]

On Friday 30 Jul 2010 5:05:56 pm Eric Noulard wrote:
> Hi All,
> I'll try to launch a specific thread for this following what
> 
> Kishore said:
> > I would like to see full support for multiple components in cpack.
> 
> David answered:
> > Could you elaborate on "full support for multiple components in cpack"
> > either in another thread, or in a feature request bug in the bug
> > tracker?
> > 
> > With NSIS on Windows and PackageMaker on Mac, we already have what I
> > would consider "full support". Are you talking about extending that to
> > additional CPack generators or is there something missing even in those
> > generators in your opinion?
> 
> An explanation on CPack Component may be found here:
>    http://www.itk.org/Wiki/CMake:Component_Install_With_CPack
> 
> As David said currently the only 2 CPack generators which support
> Components are - NSIS
>    - PackageMaker
> 
> I personally would like a wider support including RPM, DEB, TGZ (and
> may be ZIP and other archive-like).
> There is at least one bug/feature report/request for that for  CPackRPM:
> http://public.kitware.com/Bug/view.php?id=7645

Yes. This is what i mean by "full support". As a debian user, i am personally 
most attached to the DEB generator and RPM too. I have not used the NSIS 
installer for anything but the basic, so i am not sure of the level of support 
it has. But by emphasizing the DEB and RPM i also what to state that it should 
take care of dependencies between components. Like for example, If i want to 
install the component for runtime executables, it should have a dependency on 
and hence automatically install the libraries too.

Dependency information could be either explicit or implicit. Implicit would be 
the dependency between the "executables" and the "libraries" components and 
explicit could the dependency of the "headers" component on the "libraries" 
component which would need to be declared in the CMakeLists.txt file.

> From my point of view for the RPM/DEB/archive (TBZ2  TGZ   TZ    ZIP)
> COMPONENT installer there is two "global" options:
> 
> A) Put all the components in a single archive with some hierarchical
> structure inside
>     i.e. build a TGZ   whose structure may be;
>       toplevel-name/component1/...
>                           /component2/...
>       etc...
> 
> B) Build as many files as components.
>      toplevel-name-component1.tgz
>      toplevel-name-component2.tgz
>      toplevel-name-component3.tgz
> 
> The scheme A) is not quite usable for RPM or DEB
> but it is ok for "pure" archive like TBZ2 , TGZ, TZ,  ZIP.

Indeed. I opt for B.

> My **personal** opinion is that for this kind of installers I'd rather
> go for B).
> The current problem with B) is that current  CPack architecture does
> not authorize it see:
> http://public.kitware.com/Bug/view.php?id=10736
> 
> Like I said in another mail if we tackle the "multiple file problem" we
> should be able to solve the "naming convention problem" too, see:
> http://public.kitware.com/Bug/view.php?id=9900
> 
> So I would like those 2 bugs (9900, 10736)
> solved, which would enable the may-be-easy creation
> of full support for CPack COMPONENTs in any case (including bug 7645).
> 
> Please comment on those ideas or indicate whether if you agree with my
> analysis or not.
> Once we have some opinions ideas on this, I'll propose a new/updated
> API for CPack generators
> concerning this.

-- 
Cheers!
Kishore