Shared cmake (#30)

* Move cmake swig utilities into a separate cmake file
* Fix installed config file
* Upgrade CI to use focal and GCC9
* Allow external installation of examples

Author: sethrj

.travis.yml

@@ -1,4 +1,4 @@
-dist: bionic
+dist: focal
 language: shell
 os: linux
 
@@ -10,18 +10,21 @@ branches:
 # List of configurations to check
 jobs:
   include:
-    - env: FLIBCPP_DEV=ON GENERATOR=ninja
+    - env: FLIBCPP_DEV=ON GENERATOR=ninja FLIBCPP_FSTD=03
       addons:
         apt:
           packages:
+          - cmake
+          - gfortran
+          - ninja-build
           - python3-sphinx
           - valgrind
-    - env: FLIBCPP_DEV=OFF GENERATOR=make
-           FLIBCPP_FORTRAN_STD=03
-           GCC_VERSION=8
-    - env: FLIBCPP_DEV=OFF GENERATOR=make
-           FLIBCPP_FORTRAN_STD=08
-           GCC_VERSION=9
+    - env: FLIBCPP_DEV=OFF GENERATOR=make FLIBCPP_FSTD=08
+      addons:
+        apt:
+          packages:
+          - cmake
+          - gfortran
 # Build phases
 before_install:
   - source ./scripts/travis/before_install.sh

CMakeLists.txt

@@ -1,8 +1,7 @@
-#---------------------------------------------------------------------------#
-# \file CMakeLists.txt
-#
-# Copyright (c) 2019 Oak Ridge National Laboratory, UT-Battelle, LLC.
-# Distributed under an MIT open source license: see LICENSE for details.
+#---------------------------------*-CMake-*----------------------------------#
+# Copyright (c) 2019-2021 Oak Ridge National Laboratory, UT-Battelle, LLC.
+# License-Filename: LICENSE
+# SPDX-License-Identifier: MIT
 #---------------------------------------------------------------------------#
 
 cmake_minimum_required(VERSION 3.8)
@@ -14,6 +13,9 @@ cgv_find_version(Flibcpp)
 project(Flibcpp VERSION "${Flibcpp_VERSION}" LANGUAGES CXX Fortran)
 cmake_policy(VERSION 3.8...3.19)
 
+list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
+include(FlibUtils)
+
 #---------------------------------------------------------------------------#
 # OPTIONS
 #---------------------------------------------------------------------------#
@@ -40,23 +42,8 @@ endif()
 # FLAGS
 #---------------------------------------------------------------------------#
 
-# Fortran standard
-set(FLIBCPP_FORTRAN_STD "03" CACHE STRING
-   "Fortran standard for compiling generated code (options: 03/08/15/18/none)")
-if(FLIBCPP_FORTRAN_STD AND NOT FLIBCPP_FORTRAN_STD STREQUAL "none")
-  if(CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
-    set(_FLIBCPP_STD_FLAGS "-std=f20${FLIBCPP_FORTRAN_STD}")
-  elseif(CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
-    set(_FLIBCPP_STD_FLAGS "-std${FLIBCPP_FORTRAN_STD}")
-  else()
-    message(WARNING "Fortran standard flags are not known for "
-      "compilier '${CMAKE_Fortran_COMPILER_ID}': ignoring"
-      "FLIBCPP_FORTRAN_STD=${FLIBCPP_FORTRAN_STD}. Configure with "
-      "the FFLAGS environment variable or explicitly specify "
-      "CMAKE_Fortran_FLAGS")
-    set(FLIBCPP_FORTRAN_STD "none" CACHE FORCE STRING "")
-  endif()
-endif()
+# Define FLIBCPP_Fortran_STANDARD and add as Fortran compile options
+flib_fortran_standard(FLIBCPP "03")
 
 # Build type
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
@@ -73,34 +60,8 @@ endif()
 # MODULES TO LOAD
 #---------------------------------------------------------------------------#
 
-list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
-if(CMAKE_VERSION VERSION_LESS 3.18)
-  list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake/backport-cmake-318")
-endif()
-
-if(FLIBCPP_USE_SWIG)
-  if(NOT SWIG_fortran_FOUND)
-    find_package(SWIG COMPONENTS fortran REQUIRED)
-  endif()
-
-  if(CMAKE_VERSION VERSION_LESS 3.12)
-    message(FATAL_ERROR "CMake 3.12 or higher is required to regenerate the "
-      "Fortran bindings using SWIG. Set FLIBCPP_USE_SWIG to OFF "
-      "and reconfigure.")
-  endif()
-
-  if(CMAKE_VERSION GREATER_EQUAL 3.13)
-    cmake_policy(SET CMP0078 "NEW")
-  else()
-    set(FLIBCPP_CMP0078 "NEW")
-  endif()
-  if(CMAKE_VERSION GREATER_EQUAL 3.14)
-    cmake_policy(SET CMP0086 "NEW")
-  else()
-    set(FLIBCPP_CMP0086 "NEW")
-  endif()
-  include(UseSWIG)
-endif()
+# Load SWIG if FLIBCPP_USE_SWIG is true
+flib_find_and_use_swig(FLIBCPP)
 
 # Load CTest if applicable
 if(FLIBCPP_BUILD_TESTS OR FLIBCPP_BUILD_EXAMPLES)
@@ -113,60 +74,14 @@ endif()
 
 include(GNUInstallDirs)
 
-set(CMAKE_Fortran_MODULE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/module")
-set(FLIBCPP_INTERFACE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
-set(FLIBCPP_GENERATE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/src")
-set(FLIBCPP_INSTALL_CONFIGDIR "${CMAKE_INSTALL_LIBDIR}/cmake/Flibcpp")
-set(FLIBCPP_INSTALL_MODULEDIR "${CMAKE_INSTALL_INCLUDEDIR}")
 set(FLIBCPP_NAMESPACE "Flibcpp::")
+flib_dir_variables(FLIBCPP)
 
 # List of libraries exported by cmake/FlibcppConfig.cmake.in
 set(FLIBCPP_LIBRARIES)
 
 function(flibcpp_add_module name)
-  if(FLIBCPP_USE_SWIG)
-    # SWIG is available; actually generate the library dynamically.
-
-    set(src_file "${FLIBCPP_INTERFACE_DIR}/${name}.i")
-    # We're using C++
-    set_property(SOURCE "${src_file}" PROPERTY CPLUSPLUS ON)
-    # We need to include the source directory
-    set_property(SOURCE "${src_file}" PROPERTY USE_TARGET_INCLUDE_DIRECTORIES ON)
-
-    # Create the library
-    swig_add_library(${name}
-      LANGUAGE Fortran
-      TYPE USE_BUILD_SHARED_LIBS
-      OUTPUT_DIR "${FLIBCPP_GENERATE_DIR}"
-      SOURCES "${src_file}" ${ARGN}
-    )
-
-    # Add SWIG headers
-    target_include_directories(${name}
-      PUBLIC
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
-    )
-
-    # Install the interface file for downstream libraries to use
-    install(FILES
-      "${src_file}"
-      DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
-    )
-
-  else()
-    # SWIG is *not* being used: compile the code committed in the repository,
-    # generated by the developer with SWIG.
-    add_library(${name}
-      "${FLIBCPP_GENERATE_DIR}/${name}.f90"
-      "${FLIBCPP_GENERATE_DIR}/${name}FORTRAN_wrap.cxx"
-      ${ARGN}
-    )
-  endif()
-
-  # Allow the library to be referred to by its namespaced version, for use by
-  # downstream projects that *directly* compile flibcpp
-  add_library(${FLIBCPP_NAMESPACE}${name} ALIAS ${name})
+  flib_add_fortran_module(FLIBCPP ${name} "cxx" "f90" ${ARGN})
 
   # Compile C++ code with C++11
   target_compile_features(${name}
@@ -176,20 +91,9 @@ function(flibcpp_add_module name)
   # Compile with e.g. std=c++11 instead of =gnu++11
   set_property(TARGET ${name} PROPERTY CXX_EXTENSIONS OFF)
 
-  if(_FLIBCPP_STD_FLAGS)
-    # Compile Fortran code with a particular standard
-    target_compile_options(${name}
-      PUBLIC $<$<COMPILE_LANGUAGE:Fortran>:${_FLIBCPP_STD_FLAGS}>
-    )
-  endif()
-
-  target_include_directories(${name}
-    PUBLIC
-      # Fortran modules
-      $<BUILD_INTERFACE:${CMAKE_Fortran_MODULE_DIRECTORY}>
-      $<INSTALL_INTERFACE:${FLIBCPP_INSTALL_MODULEDIR}>
-  )
-
+  # Allow the library to be referred to by its namespaced version, for use by
+  # downstream projects that *directly* compile flibcpp
+  add_library(${FLIBCPP_NAMESPACE}${name} ALIAS ${name})
   # Set up installation
   install(TARGETS
     ${name}
@@ -239,6 +143,9 @@ target_link_libraries(flc_vector flc flc_string)
 # INSTALLATION
 #---------------------------------------------------------------------------#
 
+set(FLIBCPP_INSTALL_CONFIGDIR
+    "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
+
 # Install module files
 install(DIRECTORY
   "${CMAKE_Fortran_MODULE_DIRECTORY}/"