Documentation/MigrationGuide/ExternalProject

Transitioning to ExternalProject following 0c423189d

Commits: jcfr/CTK@0c423189, jcfr/ExternalProjectsContrib@f83bb40

1. Add 'ctk_include_once()' at the top

2. Remove 'ctkMacroShouldAddExternalproject' call and associated if/endif statement

Before:

 ctkMacroShouldAddExternalproject(QUAZIP_LIBRARIES add_project) # <--------- REMOVE THIS
 if(${add_project})                                             # <--------- REMOVE THIS
   [...]                                                        # Keep this block and fix indentation
 endif()                                                        # <--------- REMOVE THIS
 

After:

 [...]

3. Remove 'if(CTK_SUPERBUILD)/endif()' statement

Before:

 if(CTK_SUPERBUILD) # <--------- REMOVE THIS
   [...]            # Keep this block and fix indentation
 endif()            # <--------- REMOVE THIS

After:

 [...]

4. Remove 'CTK_DEPENDENCIES' update statement:

Before:

 [...]
 
 set(proj_DEPENDENCIES)
 
 list(APPEND CTK_DEPENDENCIES ${proj})  # <--------- REMOVE THIS
 
 set(${QuaZip_enabling_variable}_LIBRARY_DIRS QUAZIP_LIBRARY_DIRS)
 
 list(APPEND CTK_DEPENDENCIES ${proj})
 
 [...]

After:

 [...]
 
 set(proj_DEPENDENCIES)
 
 set(${QuaZip_enabling_variable}_LIBRARY_DIRS QUAZIP_LIBRARY_DIRS)
 
 list(APPEND CTK_DEPENDENCIES ${proj})
 
 [...]

5. Move 'Sanity Checks' before 'if(DEFINED ...' test

Before:

 ctk_include_once()
 
 # Sanity checks                                                                                    # <--------- CUT HERE
 if(DEFINED QuaZip_DIR AND NOT EXISTS ${QuaZip_DIR})                                                # <--------- CUT HERE
   message(FATAL_ERROR "QuaZip_DIR variable is defined but corresponds to non-existing directory")  # <--------- CUT HERE
 endif()                                                                                            # <--------- CUT HERE
 
 set(QuaZip_enabling_variable QUAZIP_LIBRARIES)
 
 [...]
 
 if(NOT DEFINED QuaZip_DIR)

After:

 ctk_include_once()
 
 set(QuaZip_enabling_variable QUAZIP_LIBRARIES)
 
 [...]
 
 # Sanity checks                                                                                    # <--------- PASTE HERE
 if(DEFINED QuaZip_DIR AND NOT EXISTS ${QuaZip_DIR})                                                # <--------- PASTE HERE
   message(FATAL_ERROR "QuaZip_DIR variable is defined but corresponds to non-existing directory")  # <--------- PASTE HERE
 endif()                                                                                            # <--------- PASTE HERE
 
 if(NOT DEFINED QuaZip_DIR)

6. Add call to 'ctkMacroCheckExternalProjectDependency' macro

Before:

 ctk_include_once()
 
 set(QuaZip_enabling_variable QUAZIP_LIBRARIES)
                                                         # <--------- REMOVE THIS
 set(proj QuaZip)                                        # <--------- REMOVE THIS
 set(proj_DEPENDENCIES)                                  # <--------- REMOVE THIS
                                                         # <--------- REMOVE THIS
 set(${QuaZip_enabling_variable}_LIBRARY_DIRS QUAZIP_LIBRARY_DIRS)
 set(${QuaZip_enabling_variable}_INCLUDE_DIRS QUAZIP_INCLUDE_DIRS)
 set(${QuaZip_enabling_variable}_FIND_PACKAGE_CMD QuaZip)
 
 # Sanity checks
 
 [...]

After:

 ctk_include_once()
 
 set(QuaZip_enabling_variable QUAZIP_LIBRARIES)
 set(${QuaZip_enabling_variable}_LIBRARY_DIRS QUAZIP_LIBRARY_DIRS)
 set(${QuaZip_enabling_variable}_INCLUDE_DIRS QUAZIP_INCLUDE_DIRS)
 set(${QuaZip_enabling_variable}_FIND_PACKAGE_CMD QuaZip)
 
 set(QuaZip_DEPENDENCIES "")                            # <--------- ADD THIS
                                                        # <--------- ADD THIS
 ctkMacroCheckExternalProjectDependency(QuaZip)         # <--------- ADD THIS
 set(proj QuaZip)                                       # <--------- ADD THIS
 
 # Sanity checks
 
 [...]

7. Add check for 'CTK_USE_SYSTEM_..' variable

Before:

 [...]
 
 ctkMacroCheckExternalProjectDependency(QuaZip)
 set(proj QuaZip)
 
 # Sanity checks
 
 [...]

After:

 [...]
 
 ctkMacroCheckExternalProjectDependency(QuaZip)
 set(proj QuaZip)
 
 if(${CMAKE_PROJECT_NAME}_USE_SYSTEM_${proj})
   message(FATAL_ERROR "Enabling ${CMAKE_PROJECT_NAME}_USE_SYSTEM_${proj} is not supported !")
 endif()
 
 # Sanity checks
 
 [...]