add new diff function

userconfig/__init__.py

@@ -173,6 +173,7 @@ class Userconfig:
             ret.set(section="Main", option="dest", value=ret.get(section="Main", option="dest")+"/")
         return ret
 
+    # FIXME remove, unused now
     @staticmethod
     def read_skip_comment(fp, comment_string):
         """Read line from filehandle fp and skip all empty (whitespace) lines and lines starting with comment_string
@@ -183,7 +184,8 @@ class Userconfig:
                     not re.match(r"^\s+$", line)):
                 yield line
 
-    def diff(self, dest_file, temp_file, comment_string):
+    # FIXME remove, unused now
+    def diff_old(self, dest_file, temp_file, comment_string):
         """diff dest_file and temp_file, returns True if files differ, False if they are the same"""
         self._cfg.debug.stdout(f'Diffing {dest_file} and {temp_file}, comment: {comment_string}', 3)
         if not os.path.isfile(dest_file):
@@ -207,6 +209,35 @@ class Userconfig:
         self._cfg.debug.stdout(f'{dest_file} is the same as generated config', 3)
         return False
 
+    @staticmethod
+    def sanitize_input(fp, comment_string):
+        """Read line from filehandle fp and skip all empty (whitespace) lines and lines starting with comment_string
+           return result as set
+        """
+        ret = set()
+        for line in fp:
+            line = line[:-1]
+            if ((comment_string != "" and not re.match("^"+re.escape(comment_string), line)) and line != "" and
+                    not re.match(r"^\s+$", line)):
+                ret.add(line)
+        return ret
+
+    def diff(self, dest_file, temp_file, comment_string):
+        """diff dest_file and temp_file, returns True if files differ, False if they are the same"""
+        self._cfg.debug.stdout(f'Diffing {dest_file} and {temp_file}, comment: {comment_string}', 3)
+        if not os.path.isfile(dest_file):
+            self._cfg.debug.stdout(f'dest_file {dest_file} does not exist.', 3)
+            return True
+        if not os.path.isfile(temp_file):
+            self._cfg.debug.stderr(f'Temporary file {temp_file} does not exist, this should not happen.', 0, 'ERROR')
+            sys.exit(1)
+
+        # get temp_file and dest_file, remove comments and whitespaces
+        temp_lines = self.sanitize_input(open(temp_file), comment_string)
+        dest_lines = self.sanitize_input(open(dest_file), comment_string)
+        # differences of temp_file and dest_file in both directions, if > 0: files differ
+        return len(temp_lines.difference(dest_lines)) + len(dest_lines.difference(temp_lines)) != 0
+
     def user_config_generated(self, filename):
         """returns True if filename has been generated by userconfig, False else"""