Add helper to use pkg-config modules

This basically creates imported targets from those pkg-config modules. It also supports static linkage. The main effort here is that those imported targets are also exported appropriately. This is implemented by letting the config script re-run pkg-config as required.
3 years ago · e114b24d3c
3 changed files with 118 additions and 13 deletions
--- a/cmake/modules/3rdParty.cmake
+++ b/cmake/modules/3rdParty.cmake
@ -44,8 +44,8 @@ endfunction ()
 function (parse_arguments_for_use_functions)
    # parse arguments
    set(OPTIONAL_ARGS OPTIONAL)
-    set(ONE_VALUE_ARGS VISIBILITY LIBRARIES_VARIABLE PACKAGES_VARIABLE TARGET_NAME)
-    set(MULTI_VALUE_ARGS)
+    set(ONE_VALUE_ARGS VISIBILITY LIBRARIES_VARIABLE PACKAGES_VARIABLE PKG_CONFIG_MODULES_VARIABLE TARGET_NAME)
+    set(MULTI_VALUE_ARGS PKG_CONFIG_MODULES)
    cmake_parse_arguments(ARGS "${OPTIONAL_ARGS}" "${ONE_VALUE_ARGS}" "${MULTI_VALUE_ARGS}" ${ARGN})

    # validate values
@ -58,20 +58,32 @@ function (parse_arguments_for_use_functions)
    if (NOT ARGS_LIBRARIES_VARIABLE)
        set(ARGS_LIBRARIES_VARIABLE "${ARGS_VISIBILITY}_LIBRARIES")
    endif ()
-    if (NOT ARGS_PACKAGES_VARIABLE AND (NOT BUILD_SHARED_LIBS OR VISIBILITY STREQUAL PUBLIC))
-        set(ARGS_PACKAGES_VARIABLE "INTERFACE_REQUIRED_PACKAGES")
-    else ()
-        set(ARGS_PACKAGES_VARIABLE "REQUIRED_PACKAGES")
+    if (NOT ARGS_PACKAGES_VARIABLE)
+        if (NOT BUILD_SHARED_LIBS OR VISIBILITY STREQUAL PUBLIC)
+            set(ARGS_PACKAGES_VARIABLE "INTERFACE_REQUIRED_PACKAGES")
+        else ()
+            set(ARGS_PACKAGES_VARIABLE "REQUIRED_PACKAGES")
+        endif ()
+    endif ()
+    if (NOT ARGS_PKG_CONFIG_MODULES_VARIABLE)
+        if (NOT BUILD_SHARED_LIBS OR VISIBILITY STREQUAL PUBLIC)
+            set(ARGS_PKG_CONFIG_MODULES_VARIABLE "INTERFACE_REQUIRED_PKG_CONFIG_MODULES")
+        else ()
+            set(ARGS_PKG_CONFIG_MODULES_VARIABLE "REQUIRED_PKG_CONFIG_MODULES")
+        endif ()
    endif ()

    # export parsed values to parent scope
    set(ARGS_VISIBILITY "${ARGS_VISIBILITY}" PARENT_SCOPE)
    set(ARGS_LIBRARIES_VARIABLE "${ARGS_LIBRARIES_VARIABLE}" PARENT_SCOPE)
    set(ARGS_PACKAGES_VARIABLE "${ARGS_PACKAGES_VARIABLE}" PARENT_SCOPE)
+    set(ARGS_PKG_CONFIG_MODULES_VARIABLE "${ARGS_PKG_CONFIG_MODULES_VARIABLE}" PARENT_SCOPE)
    set(ARGS_TARGET_NAME "${ARGS_TARGET_NAME}" PARENT_SCOPE)
+    set(ARGS_PKG_CONFIG_MODULES "${ARGS_PKG_CONFIG_MODULES}" PARENT_SCOPE)
    set(ARGS_OPTIONAL "${ARGS_OPTIONAL}" PARENT_SCOPE)
    if (NOT ARGS_OPTIONAL)
        set(ARGS_FIND_PACKAGE "REQUIRED" PARENT_SCOPE)
+        set(ARGS_PKG_CHECK_MODULES "REQUIRED" PARENT_SCOPE)
    endif ()
 endfunction ()

@ -160,6 +172,47 @@ function (use_target)
    set("${ARGS_LIBRARIES_VARIABLE}" "${${ARGS_LIBRARIES_VARIABLE}};${ARGS_TARGET_NAME}" PARENT_SCOPE)
 endfunction ()

+function(use_pkg_config_module)
+    # parse and validate arguments
+    parse_arguments_for_use_functions(${ARGN})
+    if (NOT ARGS_PKG_CONFIG_MODULES)
+        message(FATAL_ERROR "No pkg-config modules specified.")
+    endif ()
+    if (NOT ARGS_TARGET_NAME)
+        list(LENGTH ARGS_PKG_CONFIG_MODULES ARGS_PKG_CONFIG_MODULES_LENGTH)
+        if (ARGS_PKG_CONFIG_MODULES_LENGTH STREQUAL 1)
+            list(GET ARGS_PKG_CONFIG_MODULES 0 ARGS_TARGET_NAME)
+        else ()
+            message(FATAL_ERROR "No target name for multi-module pkg-config specified.")
+        endif ()
+    endif ()
+
+    # skip if target has already been added
+    if (TARGET "${ARGS_TARGET_NAME}")
+        return()
+    endif ()
+
+    find_package(PkgConfig)
+    pkg_check_modules(PKG_CHECK_MODULES_RESULT ${ARGS_PKG_CHECK_MODULES} ${ARGS_PKG_CONFIG_MODULES})
+
+    # create interface library
+    add_library(${ARGS_TARGET_NAME} INTERFACE IMPORTED)
+    if (PKG_CONFIG_USE_STATIC_LIBS)
+        set(PKG_CONFIG_CHECK_SUFFIX "_STATIC")
+    else ()
+        set(PKG_CONFIG_CHECK_SUFFIX "")
+    endif ()
+    set_property(TARGET ${ARGS_TARGET_NAME} PROPERTY INTERFACE_LINK_LIBRARIES "${PKG_CHECK_MODULES_RESULT${PKG_CONFIG_CHECK_SUFFIX}_LINK_LIBRARIES}")
+    set_property(TARGET ${ARGS_TARGET_NAME} PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${PKG_CHECK_MODULES_RESULT${PKG_CONFIG_CHECK_SUFFIX}_INCLUDE_DIRS}")
+    set_property(TARGET ${ARGS_TARGET_NAME} PROPERTY INTERFACE_COMPILE_OPTIONS "${PKG_CHECK_MODULES_RESULT${PKG_CONFIG_CHECK_SUFFIX}_CFLAGS_OTHER}")
+    set_property(TARGET ${ARGS_TARGET_NAME} PROPERTY INTERFACE_LINK_OPTIONS "${PKG_CHECK_MODULES_RESULT${PKG_CONFIG_CHECK_SUFFIX}_LDFLAGS_OTHER}")
+
+    set("${ARGS_PKG_CONFIG_MODULES_VARIABLE}" "${${ARGS_PKG_CONFIG_MODULES_VARIABLE}};${ARGS_TARGET_NAME}" PARENT_SCOPE)
+    set("${ARGS_LIBRARIES_VARIABLE}" "${${ARGS_LIBRARIES_VARIABLE}};${ARGS_TARGET_NAME}" PARENT_SCOPE)
+    string(REPLACE "::" "_" TARGET_VARNAME "${ARGS_TARGET_NAME}")
+    set("PKG_CONFIG_${TARGET_VARNAME}" "${ARGS_PKG_CONFIG_MODULES}" PARENT_SCOPE)
+endfunction()
+
 # skip subsequent configuration if only the function includes are wanted
 if (META_NO_3RDPARTY_CONFIG)
    return()
@ -200,6 +253,7 @@ if ((STATIC_LINKAGE AND META_PROJECT_IS_APPLICATION) OR (STATIC_LIBRARY_LINKAGE
    # prefer static libraries
    set(OPENSSL_USE_STATIC_LIBS ON)
    set(BOOST_USE_STATIC_LIBS ON)
+    set(PKG_CONFIG_USE_STATIC_LIBS ON)
    configure_static_library_suffixes()

 else ()
--- a/cmake/modules/LibraryTarget.cmake
+++ b/cmake/modules/LibraryTarget.cmake
@ -199,11 +199,23 @@ if (META_HEADER_ONLY_LIB)
                                     "${AUTOGEN_DEPS}")
 endif ()

+# generate CMake code to configure CMake-target to pkg-config module mapping
+set(TARGET_TO_PKG_CONFIG_MODULE_NAME_MAPPING "set(PKG_CONFIG_${META_TARGET_NAME} \"${META_PROJECT_NAME}${META_CONFIG_SUFFIX}\")")
+foreach (INTERFACE_REQUIRED_PKG_CONFIG_MODULE ${INTERFACE_REQUIRED_PKG_CONFIG_MODULES})
+    string(REPLACE "::" "_" INTERFACE_REQUIRED_PKG_CONFIG_MODULE_VARNAME "${INTERFACE_REQUIRED_PKG_CONFIG_MODULE}")
+    set(TARGET_TO_PKG_CONFIG_MODULE_NAME_MAPPING
+        "${TARGET_TO_PKG_CONFIG_MODULE_NAME_MAPPING}\nset(PKG_CONFIG_${INTERFACE_REQUIRED_PKG_CONFIG_MODULE_VARNAME} \"${PKG_CONFIG_${INTERFACE_REQUIRED_PKG_CONFIG_MODULE_VARNAME}}\")")
+endforeach ()
+
 # create the CMake package config file from template
 if (INTERFACE_REQUIRED_PACKAGES)
    list(REMOVE_ITEM INTERFACE_REQUIRED_PACKAGES "")
    list(REMOVE_DUPLICATES INTERFACE_REQUIRED_PACKAGES)
 endif ()
+if (INTERFACE_REQUIRED_PKG_CONFIG_MODULES)
+    list(REMOVE_ITEM INTERFACE_REQUIRED_PKG_CONFIG_MODULES "")
+    list(REMOVE_DUPLICATES INTERFACE_REQUIRED_PKG_CONFIG_MODULES)
+endif ()
 set(CONFIG_TARGETS "${CMAKE_CURRENT_BINARY_DIR}/${META_PROJECT_NAME}${META_CONFIG_SUFFIX}Config.cmake")
 if (META_CONFIG_SUFFIX)
    list(APPEND CONFIG_TARGETS "${CMAKE_CURRENT_BINARY_DIR}/${META_PROJECT_NAME}Config.cmake")
@ -242,15 +254,24 @@ macro (compute_dependencies_for_package_config DEPENDS OUTPUT_VAR_PKGS OUTPUT_VA
                       DEPENDENCY_VARNAME
                       "${DEPENDENCY}")
        if (PKG_CONFIG_${DEPENDENCY_VARNAME})
-            # add pkg-config name of the dependency
-            set(${OUTPUT_VAR_PKGS} "${${OUTPUT_VAR_PKGS}} ${PKG_CONFIG_${DEPENDENCY_VARNAME}}")
+            # add pkg-config modules for the dependency
+            foreach (PKG_CONFIG_MODULE ${PKG_CONFIG_${DEPENDENCY_VARNAME}})
+                set(${OUTPUT_VAR_PKGS} "${${OUTPUT_VAR_PKGS}} ${PKG_CONFIG_MODULE}")
+            endforeach ()
        elseif (TARGET "${DEPENDENCY}")
-            # add library location of the target
+            # add interface link libraries of the target
            get_target_property("${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES" "${DEPENDENCY}" "INTERFACE_LINK_LIBRARIES")
-            if (EXISTS "${${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES}")
-                set(${OUTPUT_VAR_LIBS} "${${OUTPUT_VAR_LIBS}} ${${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES}")
+            set(${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES_EXISTING FALSE)
+            foreach (LIBRARY ${${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES})
+                if (EXISTS ${LIBRARY})
+                    set(${OUTPUT_VAR_LIBS} "${${OUTPUT_VAR_LIBS}} ${LIBRARY}")
+                    set(${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES_EXISTING TRUE)
+                endif ()
+            endforeach ()
+            if (${DEPENDENCY_VARNAME}_INTERFACE_LINK_LIBRARIES_EXISTING)
                continue()
            endif ()
+            # add library location of the target
            if (META_CURRENT_CONFIGURATION)
                get_target_property("${DEPENDENCY_VARNAME}_IMPORTED_LOCATION_${META_CURRENT_CONFIGURATION}" "${DEPENDENCY}"
                                    "IMPORTED_LOCATION_${META_CURRENT_CONFIGURATION}")
--- a/cmake/templates/Config.cmake.in
+++ b/cmake/templates/Config.cmake.in
@ -26,19 +26,27 @@ set(@META_PROJECT_VARNAME_UPPER@_PRIVATE_KF_MODULES "@KF_MODULES@")
 set(@META_PROJECT_VARNAME_UPPER@_PUBLIC_QT_MODULES "@META_PUBLIC_QT_MODULES@")
 set(@META_PROJECT_VARNAME_UPPER@_PUBLIC_KF_MODULES "@META_PUBLIC_KF_MODULES@")
 set(@META_PROJECT_VARNAME_UPPER@_REQUIRED_PACKAGES "@INTERFACE_REQUIRED_PACKAGES@")
+set(@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULES "@INTERFACE_REQUIRED_PKG_CONFIG_MODULES@")
 set(@META_PROJECT_VARNAME_UPPER@_HAS_QT_TRANSLATION_FILES @APP_SPECIFIC_QT_TRANSLATIONS_AVAILABLE@)
 set(@META_PROJECT_VARNAME_UPPER@_QT_RESOURCES @QT_RESOURCES@)

+# define mapping from CMake targets to pkg-config module names
+@TARGET_TO_PKG_CONFIG_MODULE_NAME_MAPPING@
+
 # define library config, add imported target
 set(@META_PROJECT_VARNAME_UPPER@_PACKAGE "@META_PROJECT_NAME@@META_CONFIG_SUFFIX@")
 set(@META_PROJECT_VARNAME_UPPER@_LIB "@META_TARGET_NAME@")
 set(@META_PROJECT_VARNAME_UPPER@_LIB_IS_SHARED "@BUILD_SHARED_LIBS@")
 set(@META_PROJECT_VARNAME_UPPER@_STATIC_LINKAGE "@STATIC_LINKAGE_CONFIGURED@")
-set(PKG_CONFIG_@META_TARGET_NAME@ "@META_PROJECT_NAME@@META_CONFIG_SUFFIX@")
 if(NOT TARGET "${@META_PROJECT_VARNAME_UPPER@_LIB}")
+    # add target for the library itself
    include("${CMAKE_CURRENT_LIST_DIR}/@META_PROJECT_NAME@@META_CONFIG_SUFFIX@Targets.cmake")

-    # find all required packages; prefer static libraries if project was configured this way during its build
+    # make dependencies of the library available
+    # caveat: This currently does *not* cover Qt and KF modules which are so far only handled
+    #         separately when using the function use_@META_PROJECT_VARNAME@.
+
+    # prefer static libraries if @META_PROJECT_NAME@ was configured this way during its build
    if (@META_PROJECT_VARNAME_UPPER@_STATIC_LINKAGE)
        set(@META_PROJECT_VARNAME_UPPER@_DEFAULT_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
        if (WIN32)
@ -46,7 +54,11 @@ if(NOT TARGET "${@META_PROJECT_VARNAME_UPPER@_LIB}")
        else ()
            set(CMAKE_FIND_LIBRARY_SUFFIXES .a)
        endif ()
+        set(@META_PROJECT_VARNAME_UPPER@_DEFAULT_PKG_CONFIG_USE_STATIC_LIBS ${PKG_CONFIG_USE_STATIC_LIBS})
+        set(PKG_CONFIG_USE_STATIC_LIBS ON)
    endif ()
+
+    # find all required packages
    foreach (_REQUIRED_PACKAGE ${@META_PROJECT_VARNAME_UPPER@_REQUIRED_PACKAGES})
        string(REGEX MATCH _REQUIRED_PACKAGE_MATCH "(.*)-([^-]*)" "${_REQUIRED_PACKAGE}")
        if (_REQUIRED_PACKAGE_MATCH)
@ -55,9 +67,27 @@ if(NOT TARGET "${@META_PROJECT_VARNAME_UPPER@_LIB}")
            find_package("${_REQUIRED_PACKAGE}" REQUIRED)
        endif()
    endforeach()
+
+    # find all required pkg-config modules
+    if (@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULES)
+        include(3rdParty)
+        foreach (@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULE ${@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULES})
+            string(REPLACE "::" "_" @META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULE_VARNAME "${@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULE}")
+            use_pkg_config_module(
+                TARGET_NAME "${@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULE}"
+                PKG_CONFIG_MODULES "${PKG_CONFIG_${@META_PROJECT_VARNAME_UPPER@_REQUIRED_PKG_CONFIG_MODULE_VARNAME}}"
+                LIBRARIES_VARIABLE DEV_NULL
+                PKG_CONFIG_MODULES_VARIABLE DEV_NULL
+            )
+        endforeach ()
+    endif ()
+
+    # restore preference of static libraries
    if (@META_PROJECT_VARNAME_UPPER@_STATIC_LINKAGE)
        set(CMAKE_FIND_LIBRARY_SUFFIXES ${@META_PROJECT_VARNAME_UPPER@_DEFAULT_CMAKE_FIND_LIBRARY_SUFFIXES})
        unset(@META_PROJECT_VARNAME_UPPER@_DEFAULT_CMAKE_FIND_LIBRARY_SUFFIXES)
+        set(PKG_CONFIG_USE_STATIC_LIBS ${@META_PROJECT_VARNAME_UPPER@_DEFAULT_PKG_CONFIG_USE_STATIC_LIBS})
+        unset(@META_PROJECT_VARNAME_UPPER@_DEFAULT_PKG_CONFIG_USE_STATIC_LIBS)
    endif ()
 endif()