Fix <package>_SOURCE_DIR and _BINARY_DIR handling when caching is active (#314)

* fix: use CACHE variables instead relying on FetchContents mechanism

* apply cmake-format

Signed-off-by: DNKpp <DNKpp2011@gmail.com>

cmake/CPM.cmake

@@ -619,10 +619,11 @@ function(CPMAddPackage)
     get_filename_component(download_directory ${download_directory} ABSOLUTE)
     list(APPEND CPM_ARGS_UNPARSED_ARGUMENTS SOURCE_DIR ${download_directory})
     if(EXISTS ${download_directory})
-      # avoid FetchContent modules to improve performance
-      set(${CPM_ARGS_NAME}_BINARY_DIR ${CPM_FETCHCONTENT_BASE_DIR}/${lower_case_name}-build)
-      set(${CPM_ARGS_NAME}_ADDED YES)
-      set(${CPM_ARGS_NAME}_SOURCE_DIR ${download_directory})
+      cpm_store_fetch_properties(
+        ${CPM_ARGS_NAME} "${download_directory}"
+        "${CPM_FETCHCONTENT_BASE_DIR}/${lower_case_name}-build"
+      )
+      cpm_get_fetch_properties("${CPM_ARGS_NAME}")
 
       if(DEFINED CPM_ARGS_GIT_TAG)
         # warn if cache has been changed since checkout
@@ -655,7 +656,7 @@ function(CPMAddPackage)
     endif()
   endif()
 
-  cpm_create_module_file(${CPM_ARGS_NAME} "CPMAddPackage(${ARGN})")
+  cpm_create_module_file(${CPM_ARGS_NAME} "CPMAddPackage(\"${ARGN}\")")
 
   if(CPM_PACKAGE_LOCK_ENABLED)
     if((CPM_ARGS_VERSION AND NOT CPM_ARGS_SOURCE_DIR) OR CPM_INCLUDE_ALL_IN_PACKAGE_LOCK)
@@ -793,18 +794,32 @@ function(cpm_get_fetch_properties PACKAGE)
   if(${CPM_DRY_RUN})
     return()
   endif()
-  FetchContent_GetProperties(${PACKAGE})
-  string(TOLOWER ${PACKAGE} lpackage)
+
   set(${PACKAGE}_SOURCE_DIR
-      "${${lpackage}_SOURCE_DIR}"
+      "${CPM_PACKAGE_${PACKAGE}_SOURCE_DIR}"
       PARENT_SCOPE
   )
   set(${PACKAGE}_BINARY_DIR
-      "${${lpackage}_BINARY_DIR}"
+      "${CPM_PACKAGE_${PACKAGE}_BINARY_DIR}"
       PARENT_SCOPE
   )
 endfunction()
 
+function(cpm_store_fetch_properties PACKAGE source_dir binary_dir)
+  if(${CPM_DRY_RUN})
+    return()
+  endif()
+
+  set(CPM_PACKAGE_${PACKAGE}_SOURCE_DIR
+      "${source_dir}"
+      CACHE INTERNAL ""
+  )
+  set(CPM_PACKAGE_${PACKAGE}_BINARY_DIR
+      "${binary_dir}"
+      CACHE INTERNAL ""
+  )
+endfunction()
+
 # adds a package as a subdirectory if viable, according to provided options
 function(
   cpm_add_subdirectory
@@ -862,6 +877,10 @@ function(cpm_fetch_package PACKAGE populated)
     )
   endif()
 
+  cpm_store_fetch_properties(
+    ${CPM_ARGS_NAME} ${${lower_case_name}_SOURCE_DIR} ${${lower_case_name}_BINARY_DIR}
+  )
+
   set(${PACKAGE}_SOURCE_DIR
       ${${lower_case_name}_SOURCE_DIR}
       PARENT_SCOPE