better export [wip]

CMakeLists.txt

@@ -148,7 +148,7 @@ else()
 endif()
 
 
-find_package(PkgConfig)
+mapnik_find_package(PkgConfig REQUIRED)
 mapnik_find_threads()
 mapnik_find_package(ICU REQUIRED COMPONENTS uc i18n data)
 
@@ -177,7 +177,7 @@ else()
     # It might be possible that in future version harfbuzz could only be found via pkg-config.
     # harfbuzz related discussion: https://github.com/harfbuzz/harfbuzz/issues/2653
     message(STATUS "harfbuzz not found via cmake. Searching via pkg-config...")
-    pkg_check_modules(harfbuzz REQUIRED IMPORTED_TARGET harfbuzz>=${HARFBUZZ_MIN_VERSION})
+    mapnik_pkg_check_modules(harfbuzz REQUIRED IMPORTED_TARGET harfbuzz>=${HARFBUZZ_MIN_VERSION})
     list(APPEND MAPNIK_OPTIONAL_LIBS PkgConfig::harfbuzz)
 endif()
 
@@ -304,13 +304,13 @@ if(USE_TIFF)
 endif()
 
 if(USE_WEBP)
-    pkg_check_modules(WebP REQUIRED IMPORTED_TARGET libwebp)
+    mapnik_pkg_check_modules(WebP REQUIRED IMPORTED_TARGET libwebp)
     list(APPEND MAPNIK_COMPILE_DEFS HAVE_WEBP)
     list(APPEND MAPNIK_OPTIONAL_LIBS PkgConfig::WebP)
 endif()
 
 if(USE_CAIRO)
-    pkg_check_modules(Cairo REQUIRED IMPORTED_TARGET cairo)
+    mapnik_pkg_check_modules(Cairo REQUIRED IMPORTED_TARGET cairo)
     list(APPEND MAPNIK_COMPILE_DEFS HAVE_CAIRO)
     list(APPEND MAPNIK_OPTIONAL_LIBS PkgConfig::Cairo)
 endif()
@@ -321,7 +321,7 @@ if(USE_PROJ)
     # currently the cmake files are not installed, when installing proj via apt-get. So search via pkg-config
     if(NOT PROJ_FOUND)
         message(STATUS "PROJ not found via FindPROJ. Searching via pkg-config...")
-        pkg_check_modules(PROJ REQUIRED IMPORTED_TARGET proj>=${PROJ_MIN_VERSION})
+        mapnik_pkg_check_modules(PROJ REQUIRED IMPORTED_TARGET proj>=${PROJ_MIN_VERSION})
         string(REGEX MATCH "([0-9]+)\.([0-9]+)\.([0-9]+)" _dummy "${PROJ_VERSION}")
         set(PROJ_VERSION_MAJOR "${CMAKE_MATCH_1}")
         set(PROJ_VERSION_MINOR "${CMAKE_MATCH_2}")

cmake/MapnikExport.cmake

@@ -9,11 +9,26 @@ function(mapnik_export_cmake_config)
         COMPATIBILITY ExactVersion
     )
     get_property(MAPNIK_UTILITIES GLOBAL PROPERTY MAPNIK_UTILITIES)
-    list(JOIN MAPNIK_DEPENDENCIES "\n" MAPNIK_DEPENDENCIES)
+
+    # generate all find_dependency and pkg_config calls
+    set(mapnik_find_deps)
+    foreach(dep IN LISTS mapnik_deps)
+        set(ver_comment "# ${dep} used with version ${mapnik_${dep}_version}")
+        set(mapnik_find_deps "${mapnik_find_deps}\n${ver_comment}\n")
+        if(mapnik_${dep}_find_args)
+            list(REMOVE_DUPLICATES mapnik_${dep}_find_args)
+            list(JOIN mapnik_${dep}_find_args " " m_args_joined)
+            set(mapnik_find_deps "${mapnik_find_deps}find_dependency(${dep} ${m_args_joined})")
+        else()
+            list(JOIN mapnik_${dep}_pkg_args " " m_args_joined)
+            set(mapnik_find_deps "${mapnik_find_deps}pkg_check_modules(${dep} ${m_args_joined})")
+        endif()
+    endforeach()
+
     configure_package_config_file("${CMAKE_CURRENT_SOURCE_DIR}/cmake/mapnikConfig.cmake.in"
         "${CMAKE_CURRENT_BINARY_DIR}/mapnikConfig.cmake"
         INSTALL_DESTINATION ${MAPNIK_CMAKE_DIR}
-        PATH_VARS MAPNIK_INCLUDE_DIR PLUGINS_INSTALL_DIR FONTS_INSTALL_DIR MAPNIK_DEPENDENCIES MAPNIK_UTILITIES
+        PATH_VARS MAPNIK_INCLUDE_DIR PLUGINS_INSTALL_DIR FONTS_INSTALL_DIR mapnik_find_deps MAPNIK_UTILITIES
         NO_CHECK_REQUIRED_COMPONENTS_MACRO
     )
     install(

cmake/MapnikFindPackage.cmake

@@ -1,28 +1,50 @@
-macro(mapnik_print_version)
+function(mapnik_set_dep_version dep var)
-    string(TOUPPER ${ARGV0} m_package_name_upc)
+    string(TOUPPER ${dep} m_package_name_upc)
-    set(m_package_name ${ARGV0})
+    set(m_package_name ${dep})
     if(${m_package_name}_VERSION_STRING)
-        message(STATUS "Using ${m_package_name} version: ${${m_package_name}_VERSION_STRING}")
+        set(${var} ${${m_package_name}_VERSION_STRING} PARENT_SCOPE)
     elseif(${m_package_name}_VERSION)
-        message(STATUS "Using ${m_package_name} version: ${${m_package_name}_VERSION}")
+        set(${var} ${${m_package_name}_VERSION} PARENT_SCOPE)
     elseif(${m_package_name_upc}_VERSION_STRING)
-        message(STATUS "Using ${m_package_name} version: ${${m_package_name_upc}_VERSION_STRING}")
+        set(${var} ${${m_package_name_upc}_VERSION_STRING} PARENT_SCOPE)
     elseif(${m_package_name_upc}_VERSION)
-        message(STATUS "Using ${m_package_name} version: ${${m_package_name_upc}_VERSION}")
+        set(${var} ${${m_package_name_upc}_VERSION} PARENT_SCOPE)
+    endif()
+endfunction()
+
+function(mapnik_print_package_info dep)
+    message(STATUS "Using ${dep} version: ${mapnik_${dep}_version}")
+endfunction()
+
+macro(mapnik_find_package dep)
+    find_package(${dep} ${ARGN})
+    if(${dep}_FOUND)
+        list(APPEND mapnik_deps ${dep})
+
+        if(mapnik_${dep}_find_args)
+            list(APPEND mapnik_${dep}_find_args ${ARGN})
+        else()
+            set(mapnik_${dep}_find_args ${ARGN})
+        endif()
+        mapnik_set_dep_version(${dep} mapnik_${dep}_version)
+
+        mapnik_print_package_info(${dep})
     else()
-        message(STATUS "Using ${m_package_name}")
+        message(STATUS "not found: ${dep}")
     endif()
 endmacro()
 
-macro(mapnik_find_package)
+macro(mapnik_pkg_check_modules dep)
-    find_package(${ARGN})
+    pkg_check_modules(${dep} ${ARGN})
-    if(${ARGV0}_FOUND)
+    if(${dep}_FOUND)
-        set(MAPNIK_TMP_DEP ${ARGN})
+        list(APPEND mapnik_deps ${dep})
-        list(JOIN MAPNIK_TMP_DEP " " MAPNIK_TMP_DEP)
+
-        list(APPEND MAPNIK_DEPENDENCIES "find_dependency(${MAPNIK_TMP_DEP})")
+        set(mapnik_${dep}_pkg_args ${ARGN})
-        mapnik_print_version(${ARGV0})
+        mapnik_set_dep_version(${dep} mapnik_${dep}_version)
+
+        mapnik_print_package_info(${dep})
     else()
-        message(STATUS "not found: ${ARGV0}")
+        message(STATUS "not found: ${dep}")
     endif()
 endmacro()
 

cmake/mapnikConfig.cmake.in

@@ -8,7 +8,7 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_LIST_DIR}/Modules/")
 include(CMakeFindDependencyMacro)
 
 find_dependency(Threads REQUIRED)
-@MAPNIK_DEPENDENCIES@
+@mapnik_find_deps@
 
 include("${CMAKE_CURRENT_LIST_DIR}/mapnikTargets.cmake")