build: Add option to disable SWIG support

This allows disabling swig support on systems where swig is installed
but it fails building (e.g. some versions of Raspbian).

Signed-off-by: Dimitri Staessens <dimitri.staessens@ugent.be>
Signed-off-by: Sander Vrijders <sander.vrijders@ugent.be>

1 files changed, 54 insertions, 49 deletions

diff --git a/include/ouroboros/wrap/CMakeLists.txt b/include/ouroboros/wrap/CMakeLists.txt
index 43ebd242..18e695b9 100644
--- a/include/ouroboros/wrap/CMakeLists.txt
+++ b/include/ouroboros/wrap/CMakeLists.txt
@@ -5,61 +5,66 @@ find_package(SWIG QUIET)
 if (NOT SWIG_FOUND)
   message(STATUS "Install SWIG to enable bindings for other languages")
 else ()
-  message(STATUS "SWIG support enabled")
-  include(${SWIG_USE_FILE})
-  include_directories(${CMAKE_CURRENT_SOURCE_DIR})
-  set(CMAKE_SWIG_FLAGS "")
+  set(DISABLE_SWIG FALSE CACHE BOOL "Disable SWIG support")
+  if (NOT DISABLE_SWIG)
+    message(STATUS "SWIG support enabled")
+    include(${SWIG_USE_FILE})
+    include_directories(${CMAKE_CURRENT_SOURCE_DIR})
+    set(CMAKE_SWIG_FLAGS "")
 
-  find_package(PythonInterp QUIET)
-  find_package(PythonLibs QUIET)
-  if (NOT PYTHONLIBS_FOUND OR NOT PYTHONINTERP_FOUND)
-    message(STATUS "Python not found: Python bindings will not be built")
-  else ()
-    message(STATUS "Python found: Python bindings will be built")
-    include_directories(${PYTHON_INCLUDE_PATH})
+    find_package(PythonInterp QUIET)
+    find_package(PythonLibs QUIET)
+    if (NOT PYTHONLIBS_FOUND OR NOT PYTHONINTERP_FOUND)
+      message(STATUS "Python not found: Python bindings will not be built")
+    else ()
+      message(STATUS "Python found: Python bindings will be built")
+      include_directories(${PYTHON_INCLUDE_PATH})
 
-    # Python assumes C99 since Python 3.6
-    test_and_set_c_compiler_flag_global(-std=c99)
-    # SWIG generates code for varargs with an unused parameter
-    test_and_set_c_compiler_flag_global(-Wno-unused-parameter)
+      # Python assumes C99 since Python 3.6
+      test_and_set_c_compiler_flag_global(-std=c99)
+      # SWIG generates code for varargs with an unused parameter
+      test_and_set_c_compiler_flag_global(-Wno-unused-parameter)
 
-    # CMake > 3.8 deprecates swig_add_module
-    if (${CMAKE_VERSION} VERSION_LESS 3.8.0)
-      swig_add_module(ouroboros python ouroboros.i)
-    else ()
-      swig_add_library(ouroboros
-        LANGUAGE python
-        SOURCES ouroboros.i
-        TYPE MODULE)
-    endif()
+      # CMake > 3.8 deprecates swig_add_module
+      if (${CMAKE_VERSION} VERSION_LESS 3.8.0)
+        swig_add_module(ouroboros python ouroboros.i)
+      else ()
+        swig_add_library(ouroboros
+          LANGUAGE python
+          SOURCES ouroboros.i
+          TYPE MODULE)
+      endif()
 
-    swig_link_libraries(ouroboros ${PYTHON_LIBRARIES} ouroboros-common
-      ouroboros-dev ouroboros-irm)
+      swig_link_libraries(ouroboros ${PYTHON_LIBRARIES} ouroboros-common
+        ouroboros-dev ouroboros-irm)
 
-    # Installation directives
-    if (CMAKE_INSTALL_PREFIX STREQUAL "")
-      execute_process(
-        COMMAND ${PYTHON_EXECUTABLE} -c
-          "from distutils import sysconfig; print(sysconfig.get_python_lib())"
-        OUTPUT_VARIABLE PYTHON_MODULE_PATH
-        OUTPUT_STRIP_TRAILING_WHITESPACE)
-    else ()
-      execute_process(
-        COMMAND ${PYTHON_EXECUTABLE} -c
-          "from distutils import sysconfig; print(sysconfig.get_python_lib(plat_specific=True, prefix='${CMAKE_INSTALL_PREFIX}'))"
-        OUTPUT_VARIABLE _ABS_PYTHON_MODULE_PATH
-        OUTPUT_STRIP_TRAILING_WHITESPACE)
-      get_filename_component(_ABS_PYTHON_MODULE_PATH
-        ${_ABS_PYTHON_MODULE_PATH} ABSOLUTE)
-      file(RELATIVE_PATH PYTHON_MODULE_PATH
-        ${CMAKE_INSTALL_PREFIX} ${_ABS_PYTHON_MODULE_PATH})
-    endif ()
+      # Installation directives
+      if (CMAKE_INSTALL_PREFIX STREQUAL "")
+        execute_process(
+          COMMAND ${PYTHON_EXECUTABLE} -c
+            "from distutils import sysconfig; print(sysconfig.get_python_lib())"
+          OUTPUT_VARIABLE PYTHON_MODULE_PATH
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+      else ()
+        execute_process(
+          COMMAND ${PYTHON_EXECUTABLE} -c
+            "from distutils import sysconfig; print(sysconfig.get_python_lib(plat_specific=True, prefix='${CMAKE_INSTALL_PREFIX}'))"
+          OUTPUT_VARIABLE _ABS_PYTHON_MODULE_PATH
+          OUTPUT_STRIP_TRAILING_WHITESPACE)
+        get_filename_component(_ABS_PYTHON_MODULE_PATH
+          ${_ABS_PYTHON_MODULE_PATH} ABSOLUTE)
+        file(RELATIVE_PATH PYTHON_MODULE_PATH
+          ${CMAKE_INSTALL_PREFIX} ${_ABS_PYTHON_MODULE_PATH})
+      endif ()
 
-    install(FILES
-      ${CMAKE_CURRENT_BINARY_DIR}/${SWIG_MODULE_ouroboros_REAL_NAME}.so
-      DESTINATION ${PYTHON_MODULE_PATH})
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ouroboros.py
-      DESTINATION ${PYTHON_MODULE_PATH})
+      install(FILES
+        ${CMAKE_CURRENT_BINARY_DIR}/${SWIG_MODULE_ouroboros_REAL_NAME}.so
+        DESTINATION ${PYTHON_MODULE_PATH})
+      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ouroboros.py
+        DESTINATION ${PYTHON_MODULE_PATH})
+    endif ()
+  else ()
+    message(STATUS "SWIG support disabled by user")
   endif ()
 endif ()