CMake: Store Qt features in CMake Cache

This is less self-contained than what we have, but significantly speeds
up cmake configure/generate runs.

This patch also warns when a feature is already defined.

Change-Id: I8cab63e208ba98756b47d362a39b462f5ec55e20
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 27 insertions, 46 deletions

diff --git a/cmake/QtFeature.cmake b/cmake/QtFeature.cmake
index 7b8f11e896..aa18b380a6 100644
--- a/cmake/QtFeature.cmake
+++ b/cmake/QtFeature.cmake
@@ -180,7 +180,10 @@ macro(qt_feature_set_value feature cache emit_if condition label)
         message(SEND_ERROR "Feature \"${feature}\": Forcing to \"${cache}\" breaks its condition.")
     endif()
 
-    set(QT_FEATURE_${feature} "${result}" PARENT_SCOPE)
+    if (DEFINED "QT_FEATURE_${feature}")
+        message(FATAL_ERROR "Feature ${feature} is already defined when evaluating configure.cmake features for ${target}.")
+    endif()
+    set(QT_FEATURE_${feature} "${result}" CACHE INTERNAL "Qt feature: ${feature}")
 endmacro()
 
 function(qt_evaluate_feature feature)
@@ -379,8 +382,6 @@ 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)
@@ -400,55 +401,35 @@ function(qt_config_compile_test_x86simd extension label)
     set(TEST_subarch_${extension} "${TEST_X86SIMD_${extension}}" CACHE INTERNAL "${label}" )
 endfunction()
 
-function(qt_pull_features_into_current_scope)
-    cmake_parse_arguments(arg "PUBLIC_FEATURES;PRIVATE_FEATURES" "" "" ${ARGN})
-    foreach(target IN ITEMS ${arg_UNPARSED_ARGUMENTS})
-        if(NOT "${target}" MATCHES "^Qt::[a-zA-z][a-zA-Z0-9_]*$")
-            message(FATAL_ERROR "${target} does not match Qt::[a-zA-z][a-zA-Z0-9_]*. INVALID NAME.")
-        endif()
-        if(NOT TARGET ${target})
-            message(FATAL_ERROR "${target} not found.")
-        endif()
+function(qt_make_features_available target)
+    if(NOT "${target}" MATCHES "^Qt::[a-zA-z][a-zA-Z0-9_]*$")
+        message(FATAL_ERROR "${target} does not match Qt::[a-zA-z][a-zA-Z0-9_]*. INVALID NAME.")
+    endif()
+    if(NOT TARGET ${target})
+        message(FATAL_ERROR "${target} not found.")
+    endif()
 
-        get_target_property(target_type "${target}" TYPE)
-        if("${target_type}" STREQUAL "INTERFACE_LIBRARY")
-            set(property_prefix "INTERFACE_")
-        else()
-            set(property_prefix "")
-        endif()
-        foreach(visibility IN ITEMS PUBLIC PRIVATE)
-            if(NOT ${arg_${visibility}_FEATURES})
+    get_target_property(target_type "${target}" TYPE)
+    if("${target_type}" STREQUAL "INTERFACE_LIBRARY")
+        set(property_prefix "INTERFACE_")
+    else()
+        set(property_prefix "")
+    endif()
+    foreach(visibility IN ITEMS PUBLIC PRIVATE)
+        set(value ON)
+        foreach(state IN ITEMS ENABLED DISABLED)
+            get_target_property(features "${target}" ${property_prefix}QT_${state}_${visibility}_FEATURES)
+            if("${features}" STREQUAL "features-NOTFOUND")
                 continue()
             endif()
-
-            set(value ON)
-            foreach(state IN ITEMS ENABLED DISABLED)
-                get_target_property(features "${target}" ${property_prefix}QT_${state}_${visibility}_FEATURES)
-                if("${features}" STREQUAL "features-NOTFOUND")
-                    continue()
+            foreach(feature IN ITEMS ${features})
+                if (DEFINED "QT_FEATURE_${feature}")
+                    message(FATAL_ERROR "Feature ${feature} is already defined when importing features from ${target}.")
                 endif()
-                foreach(feature IN ITEMS ${features})
-                    set(QT_FEATURE_${feature} ${value} PARENT_SCOPE)
-                endforeach()
-                set(value OFF)
+                set(QT_FEATURE_${feature} "${value}" CACHE INTERNAL "Qt feature: ${feature}")
             endforeach()
+            set(value OFF)
         endforeach()
     endforeach()
 endfunction()
 
-macro(qt_push_features_into_parent_scope)
-    get_cmake_property(_variableNames VARIABLES)
-
-    foreach(_var IN ITEMS ${_variableNames})
-        if(_var MATCHES "^QT_FEATURE_[a-z][a-z0-9_]*$")
-            set("${_var}" "${${_var}}" PARENT_SCOPE)
-        endif()
-    endforeach()
-endmacro()
-
-macro(qt_load_global_features)
-    if(NOT TARGET Qt::GlobalConfig)
-       find_package(Qt${PROJECT_VERSION_MAJOR}GlobalConfig QUIET)
-    endif()
-    qt_pull_features_into_current_scope(PUBLIC_FEATURES PRIVATE_FEATURES Qt::GlobalConfig)
-endmacro()