Templates for frameworks CMake files

[Stephen Kelly]

Aurélien Gâteau wrote:

> Hi,
> 
> I have been playing around with itemviews CMake files and put together
> some templates for the top level CMakeLists.txt and *Config.cmake.in. You
> can find them attached there. Any one against me adding those to the
> repository?
> 
> Aurélien
> CMakeLists.txt
>   cmake_minimum_required(VERSION 2.8.11)

This template will be out of date whenever we require a new cmake.

>  
>  project(FooBar)
>  
>  find_package(ECM 0.0.8 REQUIRED NO_MODULE)

The latest ECM is 0.0.9

>  set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH})
>  
>  set(REQUIRED_QT_VERSION "5.2.0")

ECM and Qt version bumps are not as much an issue as the cmake one. The ECM 
and Qt version deps are not as likely to change.

>  # Required Qt5 components to build this framework
>  # For example:
>  # find_package(Qt5 ${REQUIRED_QT_VERSION} REQUIRED NO_MODULE COMPONENTS
>  # Widgets)

Simplify by putting NO_MODULE before REQUIRED and removing COMPONENTS:

 find_package(Qt5 ${REQUIRED_QT_VERSION} NO_MODULE REQUIRED Widgets)

>  if(NOT kdelibs_SOURCE_DIR)
>  find_package(KF5 5.0.0 REQUIRED MODULE COMPONENTS CMake Compiler
>  InstallDirs) # Required KF5 frameworks to build this framework

I still think this stuff is odd. We're building KF5, yet we need to find KF5 
to do so.

<snip>

>   FooBarConfigVersion.cmake.in
>   @PACKAGE_INIT@
>  
>  # Required components to use this framework
>  # For example:
>  # find_dependency(Qt5Widgets @REQUIRED_QT_VERSION@)
>  # find_dependency(KCoreAddons ${PACKAGE_VERSION})

We might want to change this before you template it. Currently,

 find_package(KAnyTier2Framework)

will result in finding its dependency with 

 find_package(KDependentTier1Framework)

ie, the dependency is not found by version unless a version is specified 
when finding KAnyTier2Framework. ie:

 find_package(KAnyTier2Framework 5.3)

will call 

 find_package(KDependentTier1Framework 5.3)

However, it might make sense for even 

 find_package(KAnyTier2Framework)

to require the same or later version as KAnyTier2Framework. 

That would be another change that would affect your template, and which 
would make 

 find_dependency(KCoreAddons ${PACKAGE_VERSION})

'wrong'.

>  
>  set(FooBar_INSTALL_PREFIX "@PACKAGE_CMAKE_INSTALL_PREFIX@")

IMO this should be removed from all config files and not added to new ones:

 http://thread.gmane.org/gmane.comp.kde.devel.frameworks/1194/focus=1318

It is unused and not useful or needed. ie  

 git grep -l PACKAGE_CMAKE_INSTALL_PREFIX | xargs \
   sed -i '/PACKAGE_CMAKE_INSTALL_PREFIX/d'

and remove the CMAKE_INSTALL_PREFIX from the configure_package_config_file 
invocations.

>  set_and_check(FooBar_INCLUDE_DIR "@PACKAGE_INCLUDE_INSTALL_DIR@")
>  set(FooBar_INCLUDE_DIRS ${FooBar_INCLUDE_DIR} )

As the include dirs are encoded into the imported targets, this is 
superfluous. No one needs to use it, and it might contain different/out of 
date information compared to what is encoded in the target.

If it is decided to remove them, then the INCLUDE_INSTALL_DIR should be 
removed from the configure_package_config_file too.

>  include("${CMAKE_CURRENT_LIST_DIR}/FooBarTargets.cmake")

Thanks,

Steve.