verification/dot2: Improve dot parser robustness

This patch makes the dot parser used by dot2c and dot2k slightly more
robust, namely:
* allows parsing files with the gv extension (GraphViz)
* correctly parses edges with any indentation
    * used to work only with a single character (e.g. '\t')
Additionally it fixes a couple of warnings reported by pylint such as
wrong indentation and comparison to False instead of `not ...`

Link: https://lore.kernel.org/20241017064238.41394-2-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: glemco

tools/verification/dot2/automata.py

@@ -29,11 +29,11 @@ def __init__(self, file_path):
 
     def __get_model_name(self):
         basename = ntpath.basename(self.__dot_path)
-        if basename.endswith(".dot") == False:
+        if not basename.endswith(".dot") and not basename.endswith(".gv"):
             print("not a dot file")
             raise Exception("not a dot file: %s" % self.__dot_path)
 
-        model_name = basename[0:-4]
+        model_name = ntpath.splitext(basename)[0]
         if model_name.__len__() == 0:
             raise Exception("not a dot file: %s" % self.__dot_path)
 
@@ -68,9 +68,9 @@ def __get_cursor_begin_states(self):
     def __get_cursor_begin_events(self):
         cursor = 0
         while self.__dot_lines[cursor].split()[0] != "{node":
-           cursor += 1
+            cursor += 1
         while self.__dot_lines[cursor].split()[0] == "{node":
-           cursor += 1
+            cursor += 1
         # skip initial state transition
         cursor += 1
         return cursor
@@ -94,11 +94,11 @@ def __get_state_variables(self):
                 initial_state = state[7:]
             else:
                 states.append(state)
-                if self.__dot_lines[cursor].__contains__("doublecircle") == True:
+                if "doublecircle" in self.__dot_lines[cursor]:
                     final_states.append(state)
                     has_final_states = True
 
-                if self.__dot_lines[cursor].__contains__("ellipse") == True:
+                if "ellipse" in self.__dot_lines[cursor]:
                     final_states.append(state)
                     has_final_states = True
 
@@ -110,7 +110,7 @@ def __get_state_variables(self):
         # Insert the initial state at the bein og the states
         states.insert(0, initial_state)
 
-        if has_final_states == False:
+        if not has_final_states:
             final_states.append(initial_state)
 
         return states, initial_state, final_states
@@ -120,7 +120,7 @@ def __get_event_variables(self):
         cursor = self.__get_cursor_begin_events()
 
         events = []
-        while self.__dot_lines[cursor][1] == '"':
+        while self.__dot_lines[cursor].lstrip()[0] == '"':
             # transitions have the format:
             # "all_fired" -> "both_fired" [ label = "disable_irq" ];
             #  ------------ event is here ------------^^^^^
@@ -161,7 +161,7 @@ def __create_matrix(self):
         # and we are back! Let's fill the matrix
         cursor = self.__get_cursor_begin_events()
 
-        while self.__dot_lines[cursor][1] == '"':
+        while self.__dot_lines[cursor].lstrip()[0] == '"':
             if self.__dot_lines[cursor].split()[1] == "->":
                 line = self.__dot_lines[cursor].split()
                 origin_state = line[0].replace('"','').replace(',','_')