CMake: Simplify Feature handling

Simplify the scope handling of features by providing a function that
just pushes all QT_FEATURES into the parent scope. Use it.

Change-Id: Ic6552fe495394d73fcec6becf6852745ec2d6d59
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 30 insertions, 50 deletions

diff --git a/cmake/QtBuild.cmake b/cmake/QtBuild.cmake
index 25cfe7e8ba..3a4f2fbc9c 100644
--- a/cmake/QtBuild.cmake
+++ b/cmake/QtBuild.cmake
@@ -442,10 +442,8 @@ function(extend_target target)
                 # caller as well as to the local scope for configure.cmake evaluation.
 
                 if("x${CMAKE_MATCH_2}" STREQUAL "xPrivate")
-                    qt_push_features_into_parent_scope(PRIVATE_FEATURES ${depTarget})
                     qt_pull_features_into_current_scope(PRIVATE_FEATURES ${depTarget})
                 endif()
-                qt_push_features_into_parent_scope(PUBLIC_FEATURES ${depTarget})
                 qt_pull_features_into_current_scope(PUBLIC_FEATURES ${depTarget})
                 if(TARGET "${dep}")
                     continue()
@@ -462,6 +460,8 @@ function(extend_target target)
         target_compile_definitions("${target}" PUBLIC ${_arg_PUBLIC_DEFINES} PRIVATE ${_arg_DEFINES})
         target_link_libraries("${target}" PUBLIC ${_arg_PUBLIC_LIBRARIES} PRIVATE ${_arg_LIBRARIES})
     endif()
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -549,20 +549,18 @@ function(add_qt_module name)
 
     # Import global features
     if(NOT "${target}" STREQUAL "Core")
-        qt_push_features_into_parent_scope(PUBLIC_FEATURES PRIVATE_FEATURES FEATURE_PROPERTY_INFIX "GLOBAL_" Qt::Core)
+        qt_pull_features_into_current_scope(PUBLIC_FEATURES PRIVATE_FEATURES FEATURE_PROPERTY_INFIX "GLOBAL_" Qt::Core)
     endif()
 
     # Fetch features from dependencies and make them available to the
     # caller as well as to the local scope for configure.cmake evaluation.
-    foreach(dep ${_arg_LIBRARIES} ${_arg_PUBLIC_LIBRARIES})
+    foreach(dep ${_arg_LIBRARIES} ${_arg_PUBLIC_LIBRARIES} ${_arg_FEATURE_DEPENDENCIES})
         if("${dep}" MATCHES "(Qt::.+)Private")
             set(publicDep ${CMAKE_MATCH_1})
-            qt_push_features_into_parent_scope(PRIVATE_FEATURES ${publicDep})
             qt_pull_features_into_current_scope(PRIVATE_FEATURES ${publicDep})
         else()
             set(publicDep ${dep})
         endif()
-        qt_push_features_into_parent_scope(PUBLIC_FEATURES ${publicDep})
         qt_pull_features_into_current_scope(PUBLIC_FEATURES ${publicDep})
     endforeach()
 
@@ -602,7 +600,7 @@ function(add_qt_module name)
         )
         include(${configureFile})
         qt_feature_module_end("${target}")
-        qt_push_features_into_parent_scope(PUBLIC_FEATURES PRIVATE_FEATURES "${target}")
+        qt_pull_features_into_current_scope(PUBLIC_FEATURES PRIVATE_FEATURES "${target}")
 
         set_property(TARGET "${target}" APPEND PROPERTY PUBLIC_HEADER "${CMAKE_CURRENT_BINARY_DIR}/qt${_arg_CONFIG_MODULE_NAME}-config.h")
         set_property(TARGET "${target}" APPEND PROPERTY PRIVATE_HEADER "${CMAKE_CURRENT_BINARY_DIR}/qt${_arg_CONFIG_MODULE_NAME}-config_p.h")
@@ -665,7 +663,7 @@ function(add_qt_module name)
         qt_internal_add_linker_version_script("${target}")
     endif()
 
-    qt_push_features_into_parent_scope(PUBLIC_FEATURES PRIVATE_FEATURES ${_arg_FEATURE_DEPENDENCIES})
+    qt_pull_features_into_current_scope(PUBLIC_FEATURES PRIVATE_FEATURES ${_arg_FEATURE_DEPENDENCIES})
 
     install(TARGETS "${target}" "${target_private}" EXPORT "${versioned_module_name}Targets"
         LIBRARY DESTINATION ${INSTALL_LIBDIR}
@@ -726,6 +724,8 @@ function(add_qt_module name)
         $<INSTALL_INTERFACE:include/${module}/${PROJECT_VERSION}>
         $<INSTALL_INTERFACE:include/${module}/${PROJECT_VERSION}/${module}>
     )
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -748,19 +748,17 @@ function(add_qt_plugin name)
     set_target_properties("${module}" PROPERTIES RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${INSTALL_BINDIR}")
 
     # Import global features
-    qt_push_features_into_parent_scope(PUBLIC_FEATURES PRIVATE_FEATURES FEATURE_PROPERTY_INFIX "GLOBAL_" Qt::Core)
+    qt_pull_features_into_current_scope(PUBLIC_FEATURES PRIVATE_FEATURES FEATURE_PROPERTY_INFIX "GLOBAL_" Qt::Core)
 
     # Fetch features from dependencies and make them available to the
     # caller as well as to the local scope for configure.cmake evaluation.
     foreach(dep ${_arg_LIBRARIES} ${_arg_PUBLIC_LIBRARIES})
         if("${dep}" MATCHES "(Qt::.+)Private")
             set(publicDep ${CMAKE_MATCH_1})
-            qt_push_features_into_parent_scope(PRIVATE_FEATURES ${publicDep})
             qt_pull_features_into_current_scope(PRIVATE_FEATURES ${publicDep})
         else()
             set(publicDep ${dep})
         endif()
-        qt_push_features_into_parent_scope(PUBLIC_FEATURES ${publicDep})
         qt_pull_features_into_current_scope(PUBLIC_FEATURES ${publicDep})
     endforeach()
 
@@ -806,6 +804,8 @@ function(add_qt_plugin name)
     endif()
 
     qt_internal_add_linker_version_script(${module})
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -838,6 +838,8 @@ function(add_qt_executable name)
         WIN32_EXECUTABLE "${_arg_GUI}"
         MACOSX_BUNDLE "${_arg_GUI}"
     )
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -862,6 +864,8 @@ function(add_qt_test name)
     set_tests_properties("${name}" PROPERTIES RUN_SERIAL "${_arg_RUN_SERIAL}")
     set_property(TEST "${name}" APPEND PROPERTY ENVIRONMENT "PATH=${_path}${QT_PATH_SEPARATOR}${CMAKE_CURRENT_BINARY_DIR}${QT_PATH_SEPARATOR}$ENV{PATH}")
     set_property(TEST "${name}" APPEND PROPERTY ENVIRONMENT "QT_PLUGIN_PATH=${PROJECT_BINARY_DIR}/${INSTALL_PLUGINSDIR}")
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -869,6 +873,7 @@ endfunction()
 # tests launch separate programs to test certainly input/output behavior.
 function(add_qt_test_helper name)
     add_qt_executable("${name}" OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}" ${ARGN})
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
@@ -899,6 +904,7 @@ function(add_qt_tool name)
     endif()
 
     install(TARGETS "${name}" EXPORT "Qt${PROJECT_VERSION_MAJOR}ToolsTargets" DESTINATION ${INSTALL_TARGETS_DEFAULT_ARGS})
+    qt_push_features_into_parent_scope()
 endfunction()
 
 
diff --git a/cmake/QtFeature.cmake b/cmake/QtFeature.cmake
index 0a19fcd6bb..6330200fd1 100644
--- a/cmake/QtFeature.cmake
+++ b/cmake/QtFeature.cmake
@@ -22,8 +22,7 @@ function(qt_feature_module_begin)
     set(__QtFeature_private_extra "" PARENT_SCOPE)
     set(__QtFeature_public_extra "" PARENT_SCOPE)
 
-    qt_push_features_into_parent_scope(PUBLIC_FEATURES ${_arg_PUBLIC_DEPENDENCIES})
-    qt_push_features_into_parent_scope(PRIVATE_FEATURES ${_arg_PRIVATE_DEPENDENCIES})
+    qt_push_features_into_parent_scope()
 endfunction()
 
 function(qt_feature _feature)
@@ -181,7 +180,6 @@ macro(qt_feature_set_value feature cache condition label)
         message(SEND_ERROR "Feature \"${feature}\": Forcing to \"${cache}\" breaks its condition.")
     endif()
 
-    set(_QT_FEATURE_VALUE_${feature} "${result}" CACHE INTERNAL "${_arg_LABEL}")
     set(QT_FEATURE_${feature} "${result}" PARENT_SCOPE)
 endmacro()
 
@@ -193,6 +191,7 @@ function(qt_evaluate_feature _feature)
     endif()
 
     if(NOT DEFINED _QT_FEATURE_DEFINITION_${_feature})
+        qt_debug_print_variables(DEDUP MATCH "^QT_FEATURE")
         message(FATAL_ERROR "Attempting to evaluate feature ${_feature} but its definition is missing. Either the feature does not exist or a dependency to the module that defines it is missing")
     endif()
 
@@ -200,8 +199,7 @@ function(qt_evaluate_feature _feature)
         "PRIVATE;PUBLIC"
         "LABEL;PURPOSE;SECTION;" "AUTODETECT;CONDITION;ENABLE;DISABLE;EMIT_IF" ${_QT_FEATURE_DEFINITION_${_feature}})
 
-    if(DEFINED _QT_FEATURE_VALUE_${_feature})
-        set(QT_FEATURE_${_feature} ${_QT_FEATURE_VALUE_${_feature}} PARENT_SCOPE)
+    if(DEFINED QT_FEATURE_${_feature})
         return()
     endif()
 
@@ -319,13 +317,7 @@ function(qt_feature_module_end target)
     list(REMOVE_DUPLICATES all_features)
 
     foreach(feature ${all_features})
-        unset(_QT_FEATURE_VALUE_${feature} CACHE)
-    endforeach()
-
-    foreach(feature ${all_features})
         qt_evaluate_feature(${feature})
-
-        set(QT_FEATURE_${feature} ${QT_FEATURE_${feature}} PARENT_SCOPE)
     endforeach()
 
     set(enabled_public_features "")
@@ -350,8 +342,7 @@ function(qt_feature_module_end target)
     endforeach()
 
     foreach(feature ${all_features})
-        unset(_QT_FEATURE_VALUE_${feature} CACHE)
-        unset(_QT_FEATURE_DEFINITION_${feature} CACHE)
+        unset(_QT_FEATURE_DEFINITION_${feature} PARENT_SCOPE)
     endforeach()
 
     _qt_feature_write_file("${CMAKE_CURRENT_BINARY_DIR}/${__QtFeature_private_file}"
@@ -389,6 +380,8 @@ function(qt_feature_module_end target)
 
     unset(__QtFeature_private_extra PARENT_SCOPE)
     unset(__QtFeature_public_extra PARENT_SCOPE)
+
+    qt_push_features_into_parent_scope()
 endfunction()
 
 function(qt_config_compile_test name)
@@ -440,33 +433,14 @@ function(qt_pull_features_into_current_scope)
 endfunction()
 
 macro(qt_push_features_into_parent_scope)
-    cmake_parse_arguments(__arg "PUBLIC_FEATURES;PRIVATE_FEATURES" "FEATURE_PROPERTY_INFIX" "" ${ARGN})
-    foreach(__target IN ITEMS ${__arg_UNPARSED_ARGUMENTS})
-        if(NOT TARGET ${__target})
-            continue()
-        endif()
-        get_target_property(__target_type "${__target}" TYPE)
-        if("${__target_type}" STREQUAL "INTERFACE_LIBRARY")
-            set(__property_prefix "INTERFACE_")
-        else()
-            set(__property_prefix "")
+    get_cmake_property(__variableNames VARIABLES)
+    list (SORT __variableNames)
+    list(REMOVE_DUPLICATES __variableNames)
+
+    foreach(__var ${__variableNames})
+        if(__var MATCHES "^QT_FEATURE_[a-z][a-z0-9_]*$")
+            set("${__var}" "${${__var}}" PARENT_SCOPE)
         endif()
-        foreach(__visibility PUBLIC PRIVATE)
-            set(__value ON)
-            foreach(__state ENABLED DISABLED)
-                if(NOT ${__arg_${__visibility}_FEATURES})
-                    continue()
-                endif()
-                get_target_property(__features "${__target}" ${__property_prefix}QT_${__arg_FEATURE_PROPERTY_INFIX}${__state}_${__visibility}_FEATURES)
-                if("${__features}" STREQUAL "__features-NOTFOUND")
-                    continue()
-                endif()
-                foreach(__feature ${__features})
-                    set(QT_FEATURE_${__feature} ${__value} PARENT_SCOPE)
-                endforeach()
-                set(__value OFF)
-            endforeach()
-        endforeach()
     endforeach()
 endmacro()