cmake: Generate INTERFACE targets for include-only modules.

Require CMake 3.0 if an attempt is made to use a cmake file containing
an INTERFACE library.

If the user is using a CMake version older than 3.0, then exclude INTERFACE
libraries from dependencies of Qt modules.  The Qt CI system is running
CMake versions as old as 2.8.11, which makes that the current minimum version.

The only header-only module existing so far is the QtUiPlugin module, which
has been split out from the QtDesigner module.  If using CMake 2.8, the
forwarding headers in the QtDesigner module will be used, and the effect
of the split out library will not be seen.  If using CMake 3.0, the
split out library is listed as a dependency and its transitive usage
requirements such as the QT_UIPLUGIN_LIB definition are made available.

Change-Id: Iecee3bbc440842dca27dc067f2a31e3526efa01b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

3 files changed, 66 insertions, 6 deletions

diff --git a/mkspecs/features/create_cmake.prf b/mkspecs/features/create_cmake.prf
index 9f7ba46c3c..395d6f247c 100644
--- a/mkspecs/features/create_cmake.prf
+++ b/mkspecs/features/create_cmake.prf
@@ -173,9 +173,28 @@ contains(CONFIG, plugin) {
 
 CMAKE_MKSPEC = $$[QMAKE_XSPEC]
 
-CMAKE_MODULE_DEPS = $$cmakeModuleList($$sort_depends(QT.$${MODULE}.depends, QT.))
-CMAKE_PARTIAL_MODULE_DEPS = $$replace(CMAKE_MODULE_DEPS, ";", ";Qt5::")
-!isEmpty(CMAKE_PARTIAL_MODULE_DEPS):CMAKE_QT5_MODULE_DEPS = "Qt5::$${CMAKE_PARTIAL_MODULE_DEPS}"
+sorted_deps = $$sort_depends(QT.$${MODULE}.depends, QT.)
+mod_deps =
+lib_deps =
+aux_mod_deps =
+aux_lib_deps =
+# Until CMake 3.0 is the minimum requirement of Qt 5, we need to filter
+# out header-only modules from dependencies.  CMake 3.0 provides INTERFACE
+# libraries which are equivalent to header-only modules.
+for (dep, sorted_deps) {
+    cdep = $$cmakeModuleName($$dep)
+    !contains(QT.$${dep}.module_config, no_link) {
+        mod_deps += $$cdep
+        lib_deps += Qt5::$$cdep
+    } else {
+        aux_mod_deps += $$cdep
+        aux_lib_deps += Qt5::$$cdep
+    }
+}
+CMAKE_MODULE_DEPS = $$join(mod_deps, ";")
+CMAKE_QT5_MODULE_DEPS = $$join(lib_deps, ";")
+CMAKE_INTERFACE_MODULE_DEPS = $$join(aux_mod_deps, ";")
+CMAKE_INTERFACE_QT5_MODULE_DEPS = $$join(aux_lib_deps, ";")
 
 CMAKE_QT_STEM = Qt$$QT_MAJOR_VERSION$${CMAKE_MODULE_NAME}$${QT_LIBINFIX}
 
diff --git a/mkspecs/features/ctest_testcase_common.prf b/mkspecs/features/ctest_testcase_common.prf
index b98a613f55..bdf40541ec 100644
--- a/mkspecs/features/ctest_testcase_common.prf
+++ b/mkspecs/features/ctest_testcase_common.prf
@@ -61,7 +61,12 @@ BUILD_DIR = $$replace($$list($$OUT_PWD/build), /, $$QMAKE_DIR_SEP)
 
 dependentmodules = $$resolve_depends(CMAKE_QT_MODULES_UNDER_TEST, "QT.")
 dependentmodules -= $$CMAKE_QT_MODULES_UNDER_TEST
-dependentmodules = $$cmakeModuleList($$dependentmodules)
+
+mod_deps =
+for (dep, dependentmodules): \
+    !contains(QT.$${dep}.module_config, no_link): \
+        mod_deps += $$cmakeModuleName($$dep)
+dependentmodules = $$join(mod_deps, ";")
 
 contains(QT_CONFIG, angle): CMAKE_GL_DEFINES = -DQT_WITH_ANGLE=True
 !contains(QT_CONFIG, egl): CMAKE_GL_DEFINES += -DNO_EGL=True
diff --git a/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in b/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
index d1dfeed535..70b9ed941a 100644
--- a/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
+++ b/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
@@ -1,7 +1,13 @@
 
+!!IF !equals(TEMPLATE, aux)
 if (CMAKE_VERSION VERSION_LESS 2.8.3)
     message(FATAL_ERROR \"Qt 5 requires at least CMake version 2.8.3\")
 endif()
+!!ELSE
+if (CMAKE_VERSION VERSION_LESS 3.0.0)
+    message(FATAL_ERROR \"Qt 5 $${CMAKE_MODULE_NAME} module requires at least CMake version 3.0.0\")
+endif()
+!!ENDIF
 
 !!IF !isEmpty(CMAKE_USR_MOVE_WORKAROUND)
 !!IF !isEmpty(CMAKE_LIB_DIR_IS_ABSOLUTE)
@@ -46,7 +52,7 @@ but not all the files it references.
     endif()
 endmacro()
 
-
+!!IF !equals(TEMPLATE, aux)
 macro(_populate_$${CMAKE_MODULE_NAME}_target_properties Configuration LIB_LOCATION IMPLIB_LOCATION)
     set_property(TARGET Qt5::$${CMAKE_MODULE_NAME} APPEND PROPERTY IMPORTED_CONFIGURATIONS ${Configuration})
 
@@ -80,6 +86,7 @@ macro(_populate_$${CMAKE_MODULE_NAME}_target_properties Configuration LIB_LOCATI
     endif()
 !!ENDIF
 endmacro()
+!!ENDIF
 
 if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
 
@@ -143,13 +150,20 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
     endif()
 !!ENDIF
 
+!!IF !equals(TEMPLATE, aux)
     set(Qt5$${CMAKE_MODULE_NAME}_INCLUDE_DIRS ${_Qt5$${CMAKE_MODULE_NAME}_OWN_INCLUDE_DIRS})
 
     set(Qt5$${CMAKE_MODULE_NAME}_DEFINITIONS -D$${MODULE_DEFINE})
     set(Qt5$${CMAKE_MODULE_NAME}_COMPILE_DEFINITIONS $${MODULE_DEFINE})
-
+!!ENDIF // TEMPLATE != aux
     set(_Qt5$${CMAKE_MODULE_NAME}_MODULE_DEPENDENCIES \"$${CMAKE_MODULE_DEPS}\")
 
+!!IF !isEmpty(CMAKE_INTERFACE_MODULE_DEPS)
+    if (NOT CMAKE_VERSION VERSION_LESS 3.0.0)
+        list(APPEND _Qt5$${CMAKE_MODULE_NAME}_MODULE_DEPENDENCIES \"$${CMAKE_INTERFACE_MODULE_DEPS}\")
+    endif()
+!!ENDIF
+
     set(_Qt5$${CMAKE_MODULE_NAME}_FIND_DEPENDENCIES_REQUIRED)
     if (Qt5$${CMAKE_MODULE_NAME}_FIND_REQUIRED)
         set(_Qt5$${CMAKE_MODULE_NAME}_FIND_DEPENDENCIES_REQUIRED REQUIRED)
@@ -163,7 +177,9 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
         set(_Qt5$${CMAKE_MODULE_NAME}_FIND_VERSION_EXACT EXACT)
     endif()
 
+!!IF !equals(TEMPLATE, aux)
     set(Qt5$${CMAKE_MODULE_NAME}_EXECUTABLE_COMPILE_FLAGS \"\")
+!!ENDIF // TEMPLATE != aux
 
     foreach(_module_dep ${_Qt5$${CMAKE_MODULE_NAME}_MODULE_DEPENDENCIES})
         if (NOT Qt5${_module_dep}_FOUND)
@@ -180,26 +196,40 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
             return()
         endif()
 
+!!IF !equals(TEMPLATE, aux)
         list(APPEND Qt5$${CMAKE_MODULE_NAME}_INCLUDE_DIRS \"${Qt5${_module_dep}_INCLUDE_DIRS}\")
         list(APPEND Qt5$${CMAKE_MODULE_NAME}_PRIVATE_INCLUDE_DIRS \"${Qt5${_module_dep}_PRIVATE_INCLUDE_DIRS}\")
         list(APPEND Qt5$${CMAKE_MODULE_NAME}_DEFINITIONS ${Qt5${_module_dep}_DEFINITIONS})
         list(APPEND Qt5$${CMAKE_MODULE_NAME}_COMPILE_DEFINITIONS ${Qt5${_module_dep}_COMPILE_DEFINITIONS})
         list(APPEND Qt5$${CMAKE_MODULE_NAME}_EXECUTABLE_COMPILE_FLAGS ${Qt5${_module_dep}_EXECUTABLE_COMPILE_FLAGS})
+!!ENDIF // TEMPLATE != aux
     endforeach()
+!!IF !equals(TEMPLATE, aux)
     list(REMOVE_DUPLICATES Qt5$${CMAKE_MODULE_NAME}_INCLUDE_DIRS)
     list(REMOVE_DUPLICATES Qt5$${CMAKE_MODULE_NAME}_PRIVATE_INCLUDE_DIRS)
     list(REMOVE_DUPLICATES Qt5$${CMAKE_MODULE_NAME}_DEFINITIONS)
     list(REMOVE_DUPLICATES Qt5$${CMAKE_MODULE_NAME}_COMPILE_DEFINITIONS)
     list(REMOVE_DUPLICATES Qt5$${CMAKE_MODULE_NAME}_EXECUTABLE_COMPILE_FLAGS)
+!!ENDIF // TEMPLATE != aux
 
     set(_Qt5$${CMAKE_MODULE_NAME}_LIB_DEPENDENCIES \"$${CMAKE_QT5_MODULE_DEPS}\")
 
+!!IF !isEmpty(CMAKE_INTERFACE_QT5_MODULE_DEPS)
+    if (NOT CMAKE_VERSION VERSION_LESS 3.0.0)
+        list(APPEND _Qt5$${CMAKE_MODULE_NAME}_LIB_DEPENDENCIES \"$${CMAKE_INTERFACE_QT5_MODULE_DEPS}\")
+    endif()
+!!ENDIF
+
 !!IF !isEmpty(CMAKE_STATIC_TYPE)
     add_library(Qt5::$${CMAKE_MODULE_NAME} STATIC IMPORTED)
     set_property(TARGET Qt5::$${CMAKE_MODULE_NAME} PROPERTY IMPORTED_LINK_INTERFACE_LANGUAGES "CXX")
 !!ELSE
+!!IF equals(TEMPLATE, aux)
+    add_library(Qt5::$${CMAKE_MODULE_NAME} INTERFACE IMPORTED)
+!!ELSE
     add_library(Qt5::$${CMAKE_MODULE_NAME} SHARED IMPORTED)
 !!ENDIF
+!!ENDIF
 !!IF !isEmpty(CMAKE_BUILD_IS_FRAMEWORK)
     set_property(TARGET Qt5::$${CMAKE_MODULE_NAME} PROPERTY FRAMEWORK 1)
 !!ENDIF
@@ -209,6 +239,7 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
     set_property(TARGET Qt5::$${CMAKE_MODULE_NAME} PROPERTY
       INTERFACE_COMPILE_DEFINITIONS $${MODULE_DEFINE})
 
+!!IF !equals(TEMPLATE, aux)
 !!IF !isEmpty(CMAKE_RELEASE_TYPE)
 !!IF !isEmpty(CMAKE_STATIC_WINDOWS_BUILD)
     _populate_$${CMAKE_MODULE_NAME}_target_properties(RELEASE \"$${CMAKE_IMPLIB_FILE_LOCATION_RELEASE}\" \"\" )
@@ -282,6 +313,11 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
 !!ENDIF // CMAKE_FIND_OTHER_LIBRARY_BUILD
 
 !!ENDIF // CMAKE_DEBUG_TYPE
+!!ELSE // TEMPLATE != aux
+    set_target_properties(Qt5::$${CMAKE_MODULE_NAME} PROPERTIES
+        INTERFACE_LINK_LIBRARIES \"${_Qt5$${CMAKE_MODULE_NAME}_LIB_DEPENDENCIES}\"
+    )
+!!ENDIF // TEMPLATE != aux
 
     file(GLOB pluginTargets \"${CMAKE_CURRENT_LIST_DIR}/Qt5$${CMAKE_MODULE_NAME}_*Plugin.cmake\")