make better use of cmake builtin funcitons for finding python library/header

1 files changed, 54 insertions, 40 deletions

diff --git a/build_files/cmake/FindPythonLibsUnix.cmake b/build_files/cmake/FindPythonLibsUnix.cmake
index 90bd79a924a..4f75fffb5ce 100644
--- a/build_files/cmake/FindPythonLibsUnix.cmake
+++ b/build_files/cmake/FindPythonLibsUnix.cmake
@@ -5,21 +5,30 @@
 #  PYTHON_LIBRARY
 #  PYTHON_LIBPATH
 #  PYTHON_LINKFLAGS
+#  PYTHON_ROOT_DIR, The base directory to search for Python.
+#                   This can also be an environment variable.
 
 #=============================================================================
 
+# If PYTHON_ROOT_DIR was defined in the environment, use it.
+IF(NOT PYTHON_ROOT_DIR AND NOT $ENV{PYTHON_ROOT_DIR} STREQUAL "")
+  SET(PYTHON_ROOT_DIR $ENV{PYTHON_ROOT_DIR})
+ENDIF()
+
+
 set(PYTHON_VERSION 3.2 CACHE STRING "")
 mark_as_advanced(PYTHON_VERSION)
 
 set(PYTHON_LINKFLAGS "-Xlinker -export-dynamic")
 mark_as_advanced(PYTHON_LINKFLAGS)
 
-set(_Python_ABI_FLAGS
+set(_python_ABI_FLAGS
 	"m;mu;u; ")
 
 string(REPLACE "." "" _PYTHON_VERSION_NO_DOTS ${PYTHON_VERSION})
 
-set(_Python_PATHS
+set(_python_SEARCH_DIRS
+	${PYTHON_ROOT_DIR}
 	"$ENV{HOME}/py${_PYTHON_VERSION_NO_DOTS}"
 	"/opt/py${_PYTHON_VERSION_NO_DOTS}"
 	"/usr"
@@ -31,54 +40,59 @@ if(NOT DEFINED PYTHON_INCLUDE_DIRS OR
    NOT DEFINED PYTHON_LIBPATH)
    
 	message(STATUS "Looking for include Python.h")
-	set(_Found_PYTHON_H OFF)
-
-	foreach(_CURRENT_PATH ${_Python_PATHS})
-		foreach(_CURRENT_ABI_FLAGS ${_Python_ABI_FLAGS})
-			if(CMAKE_BUILD_TYPE STREQUAL Debug)
-				set(_CURRENT_ABI_FLAGS "d${_CURRENT_ABI_FLAGS}")
-			endif()
-			string(REPLACE " " "" _CURRENT_ABI_FLAGS ${_CURRENT_ABI_FLAGS})
-
-			set(_Python_HEADER "${_CURRENT_PATH}/include/python${PYTHON_VERSION}${_CURRENT_ABI_FLAGS}/Python.h")
-
-			if(EXISTS ${_Python_HEADER})
-				message(STATUS "Checking for header: ${_Python_HEADER} - found")
-				set(_Found_PYTHON_H ON)
-				set(PYTHON ${_CURRENT_PATH})
-				set(PYTHON_ABI_FLAGS ${_CURRENT_ABI_FLAGS})
-				break()
-			else()
-				message(STATUS "Checking for header: ${_Python_HEADER}")
-			endif()
-		endforeach()
-		
-		if(_Found_PYTHON_H)
+
+	foreach(_CURRENT_ABI_FLAGS ${_python_ABI_FLAGS})
+		if(CMAKE_BUILD_TYPE STREQUAL Debug)
+			set(_CURRENT_ABI_FLAGS "d${_CURRENT_ABI_FLAGS}")
+		endif()
+		string(REPLACE " " "" _CURRENT_ABI_FLAGS ${_CURRENT_ABI_FLAGS})
+
+		find_path(PYTHON_INCLUDE_DIR
+			NAMES Python.h
+			HINTS ${_python_SEARCH_DIRS}
+			PATH_SUFFIXES include/python${PYTHON_VERSION}${_CURRENT_ABI_FLAGS}
+		)
+
+		find_library(PYTHON_LIBRARY
+			NAMES "python${PYTHON_VERSION}${_CURRENT_ABI_FLAGS}"
+			HINTS ${_python_SEARCH_DIRS}
+			PATH_SUFFIXES lib64 lib
+		)
+
+		if((EXISTS ${PYTHON_LIBRARY}) AND (EXISTS ${PYTHON_INCLUDE_DIR}))
+			message(STATUS "Checking for header: ${PYTHON_INCLUDE_DIR} - found")
 			break()
+		else()
+			message(STATUS "Checking for header: ${PYTHON_INCLUDE_DIR}")
 		endif()
+
+		# ensure we dont find values from 2 different ABI versions
+		unset(PYTHON_INCLUDE_DIR CACHE)
+		unset(PYTHON_LIBRARY CACHE)
 	endforeach()
 
-	if(NOT _Found_PYTHON_H)
-		message(FATAL_ERROR "Python.h not found")
+	if((EXISTS ${PYTHON_LIBRARY}) AND (EXISTS ${PYTHON_INCLUDE_DIR}))
+		# Assign cache items
+		set(PYTHON_INCLUDE_DIRS ${PYTHON_INCLUDE_DIR} CACHE STRING "")
+		set(PYTHON_LIBRARY ${PYTHON_LIBRARY} CACHE STRING "")
+		# not used
+		# set(PYTHON_BINARY ${PYTHON_EXECUTABLE} CACHE STRING "")
+
+		mark_as_advanced(
+			PYTHON_INCLUDE_DIRS
+			PYTHON_INCLUDE_DIR
+			PYTHON_LIBRARY
+		)
+	else()
+		message(FATAL_ERROR "Python not found")
 	endif()
 	
-	unset(_Found_PYTHON_H)
-	unset(_Python_HEADER)
 	unset(_CURRENT_ABI_FLAGS)
 	unset(_CURRENT_PATH)
-
-
-	set(PYTHON_INCLUDE_DIRS "${PYTHON}/include/python${PYTHON_VERSION}${PYTHON_ABI_FLAGS}" CACHE STRING "")
-	mark_as_advanced(PYTHON_INCLUDE_DIRS)
-	set(PYTHON_LIBRARY "python${PYTHON_VERSION}${PYTHON_ABI_FLAGS}" CACHE STRING "")
-	mark_as_advanced(PYTHON_LIBRARY)
-	set(PYTHON_LIBPATH ${PYTHON}/lib CACHE STRING "")
-	mark_as_advanced(PYTHON_LIBPATH)
-	# set(PYTHON_BINARY ${PYTHON_EXECUTABLE} CACHE STRING "")
 endif()
 
-unset(_Python_ABI_FLAGS)
-unset(_Python_PATHS)
+unset(_python_ABI_FLAGS)
+unset(_python_SEARCH_DIRS)
 
 #=============================================================================
 # now the python versions are found