cmake: Add a helper script which defines generator rules for eo files

eo_rule_create adds rules to generate to .eo.x .eo.h .eot.h files.
It also monitors its deps.

@feature

Makefile.am

@@ -297,7 +297,8 @@ cmakeconfig/EoConfigVersion.cmake
 eolian_cmakeconfigdir = $(libdir)/cmake/Eolian/
 eolian_cmakeconfig_DATA = \
 cmakeconfig/EolianConfig.cmake \
-cmakeconfig/EolianConfigVersion.cmake
+cmakeconfig/EolianConfigVersion.cmake \
+cmakeconfig/EolianHelper.cmake
 
 eolian_cxx_cmakeconfigdir = $(libdir)/cmake/EolianCxx/
 eolian_cxx_cmakeconfig_DATA = \

cmakeconfig/EolianHelper.cmake

@@ -0,0 +1,80 @@
+find_package(Eolian 1.16 REQUIRED)
+# macro to create a eolian generated c source file
+#
+# macro adds a generate rule, which depends on the original file the rule will output file.x
+#
+# The passed include snippet will just be added to the command
+
+macro(_rule_eox file include deps)
+    add_custom_command(
+       OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/${file}.x
+       COMMAND eolian_gen ${include} --gc -o ${CMAKE_CURRENT_SOURCE_DIR}/${file}.x ${CMAKE_CURRENT_SOURCE_DIR}/${file}
+       DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${file}
+       DEPENDS ${deps}
+    )
+endmacro()
+
+# macro to create a eolian generated header file
+#
+# other details are like the eox rule
+macro(_rule_eoh file include deps)
+    add_custom_command(
+       OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/${file}.h
+       COMMAND eolian_gen ${include} --gh -o ${CMAKE_CURRENT_SOURCE_DIR}/${file}.h ${CMAKE_CURRENT_SOURCE_DIR}/${file}
+       DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${file}
+       DEPENDS ${deps}
+    )
+endmacro()
+
+# Can be used to create .eo.x , .eo.h, .eot.h generator rules.
+# <file>.eo files are generated into <file>.eo.x and <file>.eo.h files
+# <file>.eot files are generated into <file>.eot.h files
+# The standard include path of efl eolian files is automatically added to the includes
+#
+# build_files - A list of files
+# relative_include_dirs - A list of dirs to include
+#
+# If one of the included files is changed the file will be rebuilded at the next
+# make call
+#
+# The macro scans for .eo files, hey have to be in the build_files.
+# The generator rules are just executed if the file is a dependecy of some lib/executable.
+
+function(eo_rule_create build_files relative_include_dirs)
+   string(REPLACE "\n" "" EOLIAN_EO_DIR_WITHOUT_NEWLINE "${EOLIAN_EO_DIR}")
+
+   # add std includes
+   list(APPEND include_dirs
+      ${EOLIAN_EO_DIR_WITHOUT_NEWLINE}
+    )
+
+   # convert relative to absolut
+   foreach(relative_include_dir ${relative_include_dirs})
+      list(APPEND include_dirs
+        ${CMAKE_CURRENT_SOURCE_DIR}/${relative_include_dir}
+      )
+   endforeach()
+
+   # work with the absolut paths
+   foreach(include_cmd ${include_dirs})
+      # build include cmd
+      string(CONCAT includes "${includes}" " -I${include_cmd}")
+      # fetch dep files
+      file(GLOB_RECURSE files "${include_cmd}/*.eo")
+      foreach(file ${files})
+        list(APPEND dep_files ${file})
+      endforeach()
+   endforeach()
+
+   string(REPLACE " " ";" includes "${includes}")
+   foreach(file ${build_files})
+      get_filename_component(ext ${file} EXT)
+      if (ext MATCHES "^\\.eo$")
+         _rule_eoh("${file}" "${includes}" "${dep_files}")
+         _rule_eox("${file}" "${includes}" "${dep_files}")
+      endif()
+      if (ext MATCHES "^\\.eot$")
+         _rule_eoh("${file}" "${includes}" "${dep_files}")
+      endif()
+    endforeach()
+endfunction()