1 files changed, 164 insertions, 0 deletions
diff --git a/cmake/QtPkgConfigHelpers.cmake b/cmake/QtPkgConfigHelpers.cmake
new file mode 100644
index 0000000000..dbe736c438
--- /dev/null
+++ b/cmake/QtPkgConfigHelpers.cmake
@@ -0,0 +1,164 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+function(qt_internal_collect_direct_target_dependencies target targets_out_var)
+    __qt_internal_walk_libs("${target}" "${targets_out_var}" _rcc_objects
+                            "qt_direct_targets_dict" "direct_targets")
+    set("${targets_out_var}" "${${targets_out_var}}" PARENT_SCOPE)
+endfunction()
+
+macro(qt_internal_set_pkg_config_cpp_flags var options flag)
+    set(tmpopts "${options}")
+    list(FILTER tmpopts EXCLUDE REGEX "\\$<BUILD_INTERFACE:[^,>]+>")
+    list(FILTER tmpopts EXCLUDE REGEX "\\$<TARGET_PROPERTY:[^,>]+>")
+    list(TRANSFORM tmpopts REPLACE "\\$<\\$<LINK_LANGUAGE:[^,>]+>:([^,>]+)>" "\\1")
+    list(TRANSFORM tmpopts REPLACE "\\$<INSTALL_INTERFACE:([^,>]+)>" "\\1")
+    list(TRANSFORM tmpopts REPLACE ">" "$<ANGLE-R>")
+    list(TRANSFORM tmpopts REPLACE "," "$<COMMA>")
+    set(${var} "$<$<BOOL:${tmpopts}>:${flag}$<JOIN:$<REMOVE_DUPLICATES:${tmpopts}>, ${flag}>>")
+    unset(tmpopts)
+endmacro()
+
+# Create a Qt6*.pc file intended for pkg-config consumption.
+function(qt_internal_generate_pkg_config_file module)
+    # TODO: PkgConfig is supported under MSVC with pkgconf (github.com/pkgconf/pkgconf)
+    if((NOT UNIX OR QT_FEATURE_framework)
+        AND NOT MINGW OR CMAKE_VERSION VERSION_LESS "3.20" OR ANDROID)
+        return()
+    endif()
+    if(NOT BUILD_SHARED_LIBS)
+        return()
+    endif()
+
+    set(pkgconfig_file "${QT_CMAKE_EXPORT_NAMESPACE}${module}")
+    set(pkgconfig_name "${QT_CMAKE_EXPORT_NAMESPACE} ${module}")
+    set(pkgconfig_description "Qt ${module} module")
+    set(target "${QT_CMAKE_EXPORT_NAMESPACE}::${module}")
+    set(is_interface_library "$<STREQUAL:$<TARGET_PROPERTY:${target},TYPE>,INTERFACE_LIBRARY>")
+    # The flags macro expanded this variables so it's better to set them at
+    # their corresponding PkgConfig string.
+    set(includedir "\${includedir}")
+    set(mkspecsdir "\${mkspecsdir}")
+
+    get_target_property(is_internal_module ${target} _qt_is_internal_module)
+    if(is_internal_module)
+        return()
+    endif()
+
+    get_target_property(loose_link_options ${target} INTERFACE_LINK_OPTIONS)
+    get_target_property(loose_compile_defs ${target} INTERFACE_COMPILE_DEFINITIONS)
+    get_target_property(loose_include_dirs ${target} INTERFACE_INCLUDE_DIRECTORIES)
+    list(TRANSFORM loose_include_dirs REPLACE "${INSTALL_INCLUDEDIR}" "\${includedir}")
+    list(TRANSFORM loose_include_dirs REPLACE "${INSTALL_MKSPECSDIR}" "\${mkspecsdir}")
+
+    # Remove genex wrapping around gc_sections flag because we can't evaluate genexes like
+    # $<CXX_COMPILER_ID> in file(GENERATE). And given that .pc files don't support dynamic
+    # evaluation like the $<CXX_COMPILER_ID> genex, distros will be expected to patch the .pc
+    # files according to which compiler they intend to be used with.
+    get_property(gc_sections_with_genex GLOBAL PROPERTY _qt_internal_gc_sections_with_genex)
+    get_property(gc_sections_without_genex GLOBAL PROPERTY _qt_internal_gc_sections_without_genex)
+    if(loose_link_options AND gc_sections_with_genex AND gc_sections_without_genex)
+        string(REPLACE "${gc_sections_with_genex}" "${gc_sections_without_genex}"
+            loose_link_options "${loose_link_options}")
+    endif()
+
+    qt_internal_set_pkg_config_cpp_flags(link_options "${loose_link_options}" "")
+    qt_internal_set_pkg_config_cpp_flags(compile_defs "${loose_compile_defs}" -D)
+    qt_internal_set_pkg_config_cpp_flags(include_dirs "${loose_include_dirs}" -I)
+    if("${include_dirs}" MATCHES "\\${mkspecsdir}")
+        set(contains_mkspecs TRUE)
+    endif()
+
+    # TODO: Handle macOS framework builds
+    qt_internal_collect_direct_target_dependencies(${target} loose_target_requires)
+    foreach(dep IN LISTS loose_target_requires)
+        if(dep MATCHES "^Qt::")
+            string(REGEX REPLACE "Qt" "${QT_CMAKE_EXPORT_NAMESPACE}" dep ${dep})
+        else()
+            # TODO: Figure out a way to get non-Qt requirements PkgConfig files.
+            continue()
+        endif()
+        if(NOT TARGET ${dep})
+            continue()
+        endif()
+        get_target_property(is_internal_module ${dep} _qt_is_internal_module)
+        if(is_internal_module OR dep MATCHES ".*Platform.*Internal")
+            continue()
+        endif()
+        get_target_property(type ${dep} TYPE)
+        if(type STREQUAL "INTERFACE_LIBRARY")
+            if(dep MATCHES "(.*)Private")
+                set(dep "${CMAKE_MATCH_1}")
+            endif()
+            get_target_property(type ${dep} TYPE)
+        endif()
+        string(REGEX REPLACE "::" "" req ${dep})
+        if(type STREQUAL "STATIC_LIBRARY")
+            list(APPEND target_libs -l${req})
+        else()
+            list(APPEND target_requires ${req})
+        endif()
+    endforeach()
+    string(APPEND link_options " $<JOIN:$<REMOVE_DUPLICATES:${target_libs}>, >")
+
+    qt_path_join(path_suffix "${INSTALL_LIBDIR}" pkgconfig)
+    qt_path_join(build_dir "${QT_BUILD_DIR}" "${path_suffix}")
+    qt_path_join(install_dir "${QT_INSTALL_DIR}" "${path_suffix}")
+
+    set(step_prefix "preliminary_pc_for_${pkgconfig_file}")
+    qt_path_join(template_pc "${QT_CMAKE_DIR}" PkgConfigLibrary.pc.in)
+    qt_path_join(pc_step1_path "${build_dir}" ${step_prefix}_step1.pc)
+    qt_path_join(pc_step2_path "${build_dir}" ${step_prefix}_$<CONFIG>_step2.pc)
+
+    configure_file("${template_pc}" "${pc_step1_path}" @ONLY)
+
+    file(GENERATE OUTPUT "${pc_step2_path}" INPUT "${pc_step1_path}")
+
+    if(QT_GENERATOR_IS_MULTI_CONFIG)
+        set(configs ${CMAKE_CONFIGURATION_TYPES})
+        set(rels ${configs})
+        list(FILTER rels INCLUDE REGEX "(Release|RelWithDebInfo|MinSizeRel)")
+        if(rels)
+            list(GET rels 0 release)
+        endif()
+    else()
+        set(configs ${CMAKE_BUILD_TYPE})
+        set(release ${configs})
+    endif()
+
+    foreach(config ${configs})
+        if(config STREQUAL "Debug" AND CMAKE_DEBUG_POSTFIX)
+            set(postfix ${CMAKE_DEBUG_POSTFIX})
+        elseif(NOT config STREQUAL release)
+            string(TOLOWER "_${config}" postfix)
+        else()
+            set(postfix "")
+        endif()
+
+        set(extra_args "")
+        if(NOT postfix STREQUAL "")
+            list(APPEND extra_args "-DPOSTFIX=${postfix}")
+        endif()
+
+        qt_path_join(pc_step2_path "${build_dir}" ${step_prefix}_${config}_step2.pc)
+        qt_path_join(final_pc_path "${build_dir}" ${pkgconfig_file}${postfix}.pc)
+
+        add_custom_command(
+            OUTPUT  "${final_pc_path}"
+            DEPENDS "${pc_step2_path}"
+                    "${QT_CMAKE_DIR}/QtFinishPkgConfigFile.cmake"
+            COMMAND ${CMAKE_COMMAND}
+                    "-DIN_FILE=${pc_step2_path}"
+                    "-DOUT_FILE=${final_pc_path}"
+                    ${extra_args}
+                    -P "${QT_CMAKE_DIR}/QtFinishPkgConfigFile.cmake"
+            VERBATIM
+            COMMENT "Generating pc file for target ${target}"
+            )
+
+        # This is inspired by https://gitlab.kitware.com/cmake/cmake/-/issues/20842
+        target_sources(${module} PRIVATE "${final_pc_path}")
+
+        qt_install(FILES "${final_pc_path}" DESTINATION "${install_dir}")
+    endforeach()
+endfunction()