Improve error handling in FindESMF.cmake

Modules/FindESMF.cmake

@@ -11,39 +11,38 @@
 
 
 # Add the ESMFMKFILE path to the cache if defined as system env variable
-if (DEFINED ENV{ESMFMKFILE} AND NOT DEFINED ESMFMKFILE)
+if(DEFINED ENV{ESMFMKFILE} AND NOT DEFINED ESMFMKFILE)
   set(ESMFMKFILE $ENV{ESMFMKFILE} CACHE FILEPATH "Path to ESMF mk file")
-endif ()
+endif()
 
-# Found the mk file and ESMF exists on the system
-if (EXISTS ${ESMFMKFILE})
-  set(ESMF_FOUND TRUE CACHE BOOL "ESMF mk file found" FORCE)
-  # Did not find the ESMF mk file
-else()
-  set(ESMF_FOUND FALSE CACHE BOOL "ESMF mk file NOT found" FORCE)
-  # Best to warn users that without the mk file there is no way to find ESMF
-  if (NOT DEFINED ESMFMKFILE)
-    message(FATAL_ERROR "ESMFMKFILE not defined. This is the path to esmf.mk file. \
+# If it's not explicitly set try to find esmf.mk file in default locations (ESMF_ROOT, CMAKE_PREFIX_PATH, etc)
+if(NOT DEFINED ESMFMKFILE)
+  find_path(ESMFMKFILE_PATH esmf.mk PATH_SUFFIXES lib lib64)
+  if(ESMFMKFILE_PATH)
+    set(ESMFMKFILE ${ESMFMKFILE_PATH}/esmf.mk)
+    message(STATUS "Found esmf.mk file ${ESMFMKFILE}")
+  else()
+    message(STATUS "ESMFMKFILE not defined. This is the path to esmf.mk file. \
 Without this filepath, ESMF_FOUND will always be FALSE.")
-  endif ()
+  endif()
 endif()
 
 # Only parse the mk file if it is found
-if (ESMF_FOUND)
+if(EXISTS ${ESMFMKFILE})
   # Read the mk file
   file(STRINGS "${ESMFMKFILE}" esmfmkfile_contents)
   # Parse each line in the mk file
   foreach(str ${esmfmkfile_contents})
     # Only consider uncommented lines
     string(REGEX MATCH "^[^#]" def ${str})
     # Line is not commented
-    if (def)
+    if(def)
       # Extract the variable name
       string(REGEX MATCH "^[^=]+" esmf_varname ${str})
       # Extract the variable's value
       string(REGEX MATCH "=.+$" esmf_vardef ${str})
       # Only for variables with a defined value
-      if (esmf_vardef)
+      if(esmf_vardef)
         # Get rid of the assignment string
         string(SUBSTRING ${esmf_vardef} 1 -1 esmf_vardef)
         # Remove whitespace
@@ -62,7 +61,7 @@ if (ESMF_FOUND)
               # Promote to global scope
               set(${esmf_varname} ${esmf_vardef})
               # Don't display by default in the GUI
-              mark_as_advanced (esmf_varname)
+              mark_as_advanced(esmf_varname)
               # No need to search for the current string filter
               break()
             endif()
@@ -72,59 +71,53 @@ if (ESMF_FOUND)
     endif()
   endforeach()
 
-  # Construct ESMF_VERSION from ESMF_VERSION_STRING_GIT
-  if(ESMF_FOUND)
-    # ESMF_VERSION_MAJOR and ESMF_VERSION_MINOR are defined in ESMFMKFILE
-    set(ESMF_VERSION 0)
-    set(ESMF_VERSION_PATCH ${ESMF_VERSION_REVISION})
-    set(ESMF_BETA_RELEASE FALSE)
-    if(ESMF_VERSION_BETASNAPSHOT MATCHES "^('T')$")
-      set(ESMF_BETA_RELEASE TRUE)
-      string(REGEX REPLACE ".*beta_snapshot_*\([0-9]*\).*" "\\1" ESMF_BETA_SNAPSHOT "${ESMF_VERSION_STRING_GIT}")
-    endif()
-    set(ESMF_VERSION "${ESMF_VERSION_MAJOR}.${ESMF_VERSION_MINOR}.${ESMF_VERSION_PATCH}")
-  endif()
-
   separate_arguments(ESMF_F90COMPILEPATHS NATIVE_COMMAND ${ESMF_F90COMPILEPATHS})
-  foreach (ITEM ${ESMF_F90COMPILEPATHS})
+  foreach(ITEM ${ESMF_F90COMPILEPATHS})
      string(REGEX REPLACE "^-I" "" ITEM "${ITEM}")
      list(APPEND tmp ${ITEM})
   endforeach()
   set(ESMF_F90COMPILEPATHS ${tmp})
 
-  add_library(esmf UNKNOWN IMPORTED)
   # Look for static library, if not found try dynamic library
   find_library(esmf_lib NAMES libesmf.a PATHS ${ESMF_LIBSDIR})
   if(esmf_lib MATCHES "esmf_lib-NOTFOUND")
+    unset(esmf_lib)
     message(STATUS "Static ESMF library not found, searching for dynamic library instead")
-    find_library(esmf_lib NAMES esmf_fullylinked PATHS ${ESMF_LIBSDIR})
+    find_library(esmf_lib NAMES esmf_fullylinked libesmf.so PATHS ${ESMF_LIBSDIR})
     if(esmf_lib MATCHES "esmf_lib-NOTFOUND")
-      message(FATAL_ERROR "Neither the dynamic nor the static ESMF library was found")
+      unset(esmf_lib)
+      message(STATUS "Neither the dynamic nor the static ESMF library was found")
+    else()
+      set(_library_type SHARED)
     endif()
-    set(ESMF_INTERFACE_LINK_LIBRARIES "")
   else()
-    # When linking the static library, also need the ESMF linker flags; strip any leading/trailing whitespaces
-    string(STRIP "${ESMF_F90ESMFLINKRPATHS} ${ESMF_F90ESMFLINKPATHS} ${ESMF_F90LINKPATHS} ${ESMF_F90LINKLIBS} ${ESMF_F90LINKOPTS}" ESMF_INTERFACE_LINK_LIBRARIES)
+    set(_library_type STATIC)
   endif()
 
-  message(STATUS "Found ESMF library: ${esmf_lib}")
-  if(ESMF_BETA_RELEASE)
-    message(STATUS "Detected ESMF Beta snapshot ${ESMF_BETA_SNAPSHOT}")
-  endif()
+  string(STRIP "${ESMF_F90ESMFLINKRPATHS} ${ESMF_F90ESMFLINKPATHS} ${ESMF_F90LINKPATHS} ${ESMF_F90LINKLIBS} ${ESMF_F90LINKOPTS}" ESMF_INTERFACE_LINK_LIBRARIES)
+  set(ESMF_LIBRARY_LOCATION ${esmf_lib})
 
-  set_target_properties(esmf PROPERTIES
-    IMPORTED_LOCATION ${esmf_lib}
-    INTERFACE_INCLUDE_DIRECTORIES "${ESMF_F90COMPILEPATHS}"
-    INTERFACE_LINK_LIBRARIES "${ESMF_INTERFACE_LINK_LIBRARIES}")
+else()
+
+  message(WARNING "ESMFMKFILE ${ESMFMKFILE} does not exist")
 
 endif()
 
 ## Finalize find_package
 include(FindPackageHandleStandardArgs)
 
-find_package_handle_standard_args( ${CMAKE_FIND_PACKAGE_NAME}
-    REQUIRED_VARS ESMF_LIBSDIR
+find_package_handle_standard_args(
+    ${CMAKE_FIND_PACKAGE_NAME}
+    REQUIRED_VARS ESMF_LIBRARY_LOCATION
                   ESMF_INTERFACE_LINK_LIBRARIES
                   ESMF_F90COMPILEPATHS
-    VERSION_VAR ESMF_VERSION
-    HANDLE_COMPONENTS )
+    VERSION_VAR ESMF_VERSION_STRING)
+
+## If ESMF is found create imported library target
+if(ESMF_FOUND)
+  add_library(esmf ${_library_type} IMPORTED)
+  set_target_properties(esmf PROPERTIES
+    IMPORTED_LOCATION "${ESMF_LIBRARY_LOCATION}"
+    INTERFACE_INCLUDE_DIRECTORIES "${ESMF_F90COMPILEPATHS}"
+    INTERFACE_LINK_LIBRARIES "${ESMF_INTERFACE_LINK_LIBRARIES}")
+endif()