Improve coding style in CMake modules

cmake/modules/3rdParty.cmake

@@ -1,6 +1,10 @@
 cmake_minimum_required(VERSION 3.3.0 FATAL_ERROR)
 
-if(NOT DEFINED THIRD_PARTY_MODULE_LOADED)
+# prevent multiple inclusion
+if(DEFINED THIRD_PARTY_MODULE_LOADED)
+    return()
+endif()
+set(THIRD_PARTY_MODULE_LOADED YES)
 
 macro(save_default_library_suffixes)
     set(DEFAULT_CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES})
@@ -267,6 +271,3 @@ if(NOT DEFINED THIRD_PARTY_MODULE_LOADED)
         use_external_library(iconv ${LINKAGE} ${REQUIRED})
     endif()
 endmacro()
-
-    set(THIRD_PARTY_MODULE_LOADED YES)
-endif()

cmake/modules/Doxygen.cmake

@@ -3,8 +3,10 @@ if(NOT BASIC_PROJECT_CONFIG_DONE)
 endif()
 
 option(NO_DOXYGEN "whether creation of Doxygen targets is disabled (enabled by default)" OFF)
-
 if(NOT NO_DOXYGEN)
+    return()
+endif()
+
 # find doxygen.h template
 include(TemplateFinder)
 find_template_file("doxygen" CPP_UTILITIES DOXYGEN_TEMPLATE_FILE)
@@ -27,7 +29,9 @@ if(NOT NO_DOXYGEN)
 
 if(NOT DOXYGEN_BIN)
     message(WARNING "Doxygen not found, unable to add target for generating API documentation for ${TARGET_PREFIX}${META_PROJECT_NAME}${TARGET_SUFFIX}")
-    else()
+    return()
+endif()
+
 # load cached configuration and other variables
 set(DOXY_LANGUAGE "English" CACHE STRING "specifies the language of the API documentation generated with Doxygen")
 set(DOXY_CUSTOM_CONFIG "" CACHE STRING "specifies extra options for Doxygen")
@@ -75,6 +79,3 @@ if(NOT NO_DOXYGEN)
 endif()
 
 message(STATUS "Generating target for generating API documentation for ${TARGET_PREFIX}${META_PROJECT_NAME}${TARGET_SUFFIX} with Doxygen")
-
-    endif()
-endif()

cmake/modules/ShellCompletion.cmake

@@ -4,8 +4,10 @@ endif()
 
 option(SHELL_COMPLETION_ENABLED "controls whether shell completion is enabled in general" ON)
 option(BASH_COMPLETION_ENABLED "controls whether shell completion for bash is enabled" ON)
+if(NOT SHELL_COMPLETION_ENABLED)
+    return()
+endif()
 
-if(SHELL_COMPLETION_ENABLED)
 # add bash completion (currently the only supported shell completion)
 if(BASH_COMPLETION_ENABLED)
     # find bash-completion.sh template
@@ -34,4 +36,3 @@ if(SHELL_COMPLETION_ENABLED)
 
     message(STATUS "Generating files for bash completion.")
 endif()
-endif()

cmake/modules/TemplateFinder.cmake

@@ -1,4 +1,8 @@
-if(NOT DEFINED TEMPLATE_FINDER_LOADED)
+# prevent multiple inclusion
+if(DEFINED TEMPLATE_FINDER_LOADED)
+    return()
+endif()
+set(TEMPLATE_FINDER_LOADED YES)
 
 function(find_template_file FILE_NAME PROJECT_VAR_NAME OUTPUT_VAR)
     if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/cmake/templates/${FILE_NAME}.in")
@@ -17,6 +21,3 @@ if(NOT DEFINED TEMPLATE_FINDER_LOADED)
         message(FATAL_ERROR "Template for ${FILE_NAME} file can not be located.")
     endif()
 endfunction()
-
-    set(TEMPLATE_FINDER_LOADED YES)
-endif()

cmake/modules/WindowsResources.cmake

@@ -6,10 +6,13 @@ if(NOT BASIC_PROJECT_CONFIG_DONE)
     message(FATAL_ERROR "Before including the WindowsResources module, the LibraryConfig/ApplicationConfig module must be included.")
 endif()
 
-option(WINDOWS_RESOURCES_ENABLED "controls Windows resources are enabled" ON)
-option(WINDOWS_ICON_ENABLED "controls Windows icon is enabled" ON)
+option(WINDOWS_RESOURCES_ENABLED "controls whether Windows resources are enabled" ON)
+option(WINDOWS_ICON_ENABLED "controls whether Windows icon is enabled" ON)
+
+if(NOT MINGW OR NOT WINDOWS_RESOURCES_ENABLED)
+    return()
+endif()
 
-if(MINGW AND WINDOWS_RESOURCES_ENABLED)
 # find rc template
 include(TemplateFinder)
 find_template_file("windows.rc" CPP_UTILITIES RC_TEMPLATE_FILE)
@@ -42,7 +45,7 @@ if(MINGW AND WINDOWS_RESOURCES_ENABLED)
             message(FATAL_ERROR "The specified PNG_ICON_PATH \"${PNG_ICON_PATH}\" is invalid.")
         endif()
         unset(USING_DEFAULT_PNG_ICON_PATH)
-        endif(FFMPEG_BIN)
+    endif()
 endif()
 
 # create Windows rc file from template
@@ -55,4 +58,3 @@ if(MINGW AND WINDOWS_RESOURCES_ENABLED)
 set(CMAKE_RC_COMPILER_INIT windres)
 set(CMAKE_RC_COMPILE_OBJECT "<CMAKE_RC_COMPILER> <FLAGS> -O coff <DEFINES> -i <SOURCE> -o <OBJECT>")
 enable_language(RC)
-endif()