# - Dunecontrol compatibility
#
# Enables this build to be a part of a dunecontrol chain. The
# DUNE_CHECK_MODULES macro greps the top-level Makefile for the
# presence of the abs_top_srcdir variable (!) and uses that as
# the include directory of a module. Also, the contents are not
# checked so if the variable is not present, it generates an
# invalid command line (-I without argument) which causes the
# autoconf probe to fail. This module patches our Makefile (!!)
# so the necessary string will be there; in itself this string
# has no use for us, it is solemnly to satisfy the M4 scripts.

if (CMAKE_GENERATOR MATCHES "Unix Makefiles")
  # we need an up-to-date, patched Makefile. this is always checked when
  # the makefile is run, thus the need for a marker file to keep a
  # timestamp to see when it was last patched (by us)
  # amazingly, nothing depends on the generated Makefile, so this can be
  # run whenever in the build without trigging a compile of e.g. config.h
  add_custom_target (dune-compat ALL
	COMMAND ${CMAKE_COMMAND} -DCMAKE_HOME_DIRECTORY=${CMAKE_HOME_DIRECTORY} -P ${OPM_MACROS_ROOT}/cmake/Scripts/DuneCompat2.cmake
	COMMENT "Patching Makefile to be DUNE compatible"
	)
endif (CMAKE_GENERATOR MATCHES "Unix Makefiles")

# dunecontrol refuses to use a build tree as module directory unless
# there is a dune.module in it. however, if we are in a sub-dir. of
# the source, we are probably using dunecontrol with a --build-dir
# argument, and won't call dunecontrol from the parent (which is the
# source dir and most likely doesn't contain other projects) anyway,
# i.e. we only copy if we are truly out-of-source
string (LENGTH "${PROJECT_SOURCE_DIR}/" _src_dir_len)
string (LENGTH "${PROJECT_BINARY_DIR}/" _bin_dir_len)
if (_src_dir_len GREATER _bin_dir_len)
  set (_not_substring TRUE)
else (_src_dir_len GREATER _bin_dir_len)
  string (SUBSTRING "${PROJECT_BINARY_DIR}/" 0 ${_src_dir_len} _proj_prefix)
  if ("${PROJECT_SOURCE_DIR}/" STREQUAL "${_proj_prefix}")
	set (_not_substring FALSE)
  else ("${PROJECT_SOURCE_DIR}/" STREQUAL "${_proj_prefix}")
	set (_not_substring TRUE)
  endif ("${PROJECT_SOURCE_DIR}/" STREQUAL "${_proj_prefix}")
endif (_src_dir_len GREATER _bin_dir_len)
if (_not_substring)
  execute_process (COMMAND
	${CMAKE_COMMAND} -E copy_if_different ${PROJECT_SOURCE_DIR}/dune.module ${PROJECT_BINARY_DIR}/dune.module
	)
endif (_not_substring)