Parse version from directory name if not a git repository. (#142)

If the oxDNA folder is not a git repo, parse the version from directory name, or set it to unknown/none when info cannot be extracted in any way. Fixes #141

CMakeLists.txt

@@ -125,11 +125,30 @@ endif(JSON_ENABLED)
 # get the current git revision, if git is installed. Avoid warnings if it isn't
 FIND_PACKAGE(Git)
 IF(Git_FOUND)
+	EXECUTE_PROCESS(COMMAND ${GIT_EXECUTABLE} rev-parse --git-dir WORKING_DIRECTORY ${PROJECT_SOURCE_DIR} OUTPUT_VARIABLE git_dir OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
+	IF(git_dir STREQUAL "${PROJECT_SOURCE_DIR}/.git")
+		SET(IS_GIT_REPO TRUE) 
+	ELSE()
+		SET(IS_GIT_REPO FALSE)
+	ENDIF()
+ELSE()
+	SET(IS_GIT_REPO FALSE)
+ENDIF(Git_FOUND)
+
+IF(IS_GIT_REPO)
 	EXECUTE_PROCESS(COMMAND ${GIT_EXECUTABLE} rev-parse --short HEAD WORKING_DIRECTORY ${PROJECT_SOURCE_DIR} OUTPUT_VARIABLE revision OUTPUT_STRIP_TRAILING_WHITESPACE)
 	EXECUTE_PROCESS(COMMAND ${GIT_EXECUTABLE} describe --tags --abbrev=0 HEAD WORKING_DIRECTORY ${PROJECT_SOURCE_DIR} OUTPUT_VARIABLE tag OUTPUT_STRIP_TRAILING_WHITESPACE)
 ELSE()
-	SET(revision GIT_NOT_FOUND)
-ENDIF(Git_FOUND)
+	get_filename_component(dir_name ${PROJECT_SOURCE_DIR} NAME)
+	string(REGEX MATCH "-([0-9]+\\.[0-9]+\\.[0-9]+.*)$" version_match ${dir_name})
+	SET(revision "none")
+	if(version_match)
+		SET(tag "v${CMAKE_MATCH_1}")
+	else()
+		SET(tag "unknown")
+	endif()
+ENDIF(IS_GIT_REPO)
+
 
 # return the current date as day/month/year
 MACRO(CURRENT_DATE result)