[CMake] CPack and configure_file

[Michael Hertling]

On 01/11/2011 09:48 AM, Eric Noulard wrote:
> 2011/1/11 Michael Hertling <mhertling at online.de>:
>> On 01/11/2011 12:55 AM, Tobias Ellinghaus wrote:
>>>
>>> Because some information (like latest git commit as version string) is no
>>> longer available when using a source package. Of course I can put the
>>> generated files into the source tree, but that's kind of against the idea of
>>> out-of-source builds.
>>
>> You might use "cmake --build" in conjunction with a custom target:
>>
>> CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
>> PROJECT(PKGSRC NONE)
>> IF(EXISTS ${CMAKE_SOURCE_DIR}/manifest.txt)
>>    # In packaged source tree.
>>    FILE(COPY ${CMAKE_SOURCE_DIR}/manifest.txt
>>         DESTINATION ${CMAKE_BINARY_DIR})
>> ELSE()
>>    # In original source tree.
>>    FILE(WRITE ${CMAKE_BINARY_DIR}/manifest.txt "...\n")
>>    INCLUDE(CPack)
>>    ADD_CUSTOM_TARGET(pkgsrc
>>        COMMAND ${CMAKE_COMMAND}
>>            -E copy ${CMAKE_BINARY_DIR}/manifest.txt
>>                    ${CMAKE_SOURCE_DIR}/manifest.txt
>>        COMMAND ${CMAKE_COMMAND}
>>            --build ${CMAKE_BINARY_DIR}
>>            --target package_source
>>        COMMAND ${CMAKE_COMMAND}
>>            -E remove ${CMAKE_SOURCE_DIR}/manifest.txt
>>    )
>> ENDIF()
> 
> Nice solution.
> 
>> The pkgsrc target prepares the source tree for packaging, builds the
>> source package via "cmake --build" and cleans up. AFAICS, writing to
>> the source tree is unavoidable in order to achieve your aim,
> 
> in fact I think the "real" source for this is the fact the CPack lacks
> the notion
> of "EXTRA" distribution file which is available with autoconf, EXTRA_DIST var
> http://www.gnu.org/software/hello/manual/automake/Basics-of-Distribution.html
> or the dist-hook:
> http://www.gnu.org/software/hello/manual/automake/The-dist-Hook.html#The-dist-Hook
> 
> The fact is CPack doesn't know much about "source package" and
> in fact it package source using the CPACK_INSTALLED_DIRECTORIES directory list.
> (look at the generated CPackSourceConfig.cmake)
> 
> I think you can "emulate" the extra thing of autoconf.
> If you want ot package "more" than the source tree with
> "package_source" you can try
> the following in your main CMakeLists.txt (before include(CPack))
> 
> SET(CPACK_SOURCE_INSTALLED_DIRECTORIES
> "${CMAKE_SOURCE_DIR};/;${CMAKE_BINARY_DIR}/extra;/extra")
> 
> then the content of the directory
> ${CMAKE_BINARY_DIR}/extra will added in the package source archive
> inside "extra" dir.
> 
> it should work.

Indeed, it does; thanks for this hint, Eric. :)

Just two remarks about that solution from my side:

1) Is it an official feature? The CPACK_SOURCE_INSTALLED_DIRECTORIES
   variable is not documented anywhere and does hardly appear on the
   ML or the BT, and even G**gle says that it is used rather seldom.
2) In contrast to the usual "package" target, there is no dependency
   of "package_source" on "all", so one will possibly miss something
   if the source package ingredients need to be set up at build time.

AFAICS, the latter can be addressed with CPACK_INSTALL_COMMANDS set to
"${CMAKE_COMMAND} --build ${CMAKE_BINARY_DIR}" or whatever is necessary
to prepare the source tree for packaging, but there's no source-package
specific CPACK_SOURCE_INSTALL_COMMANDS variable or the like. Perhaps,
this is worth a feature request as concerns like the OP's one, i.e.
the addition of certain build-time generated files to the source
package, are somewhat reasonable, IMO.

Regards,

Michael