chore: Improved setup by 40% changing state and transitions callbacks setup to factory (run only once per class instead of by instance creation (#433)

Author: fgmacedo

docs/conf.py

@@ -66,7 +66,7 @@
 
 # General information about the project.
 project = "Python State Machine"
-copyright = "2023, Fernando Macedo"
+copyright = "2024, Fernando Macedo"
 
 # The version info for the project you're documenting, acts as replacement
 # for |version| and |release|, also used in various other places throughout

docs/images/order_control_machine_initial.png

@@ -10,6 +10,7 @@
 from .event import Event
 from .event import trigger_event_factory
 from .exceptions import InvalidDefinition
+from .graph import iterate_states_and_transitions
 from .graph import visit_connected_states
 from .i18n import _
 from .state import State
@@ -38,6 +39,7 @@ def __init__(
         cls._abstract = True
         cls._strict_states = strict_states
         cls._events: Dict[str, Event] = {}
+        cls._protected_attrs: set = set()
 
         cls.add_inherited(bases)
         cls.add_from_attributes(attrs)
@@ -50,6 +52,7 @@ def __init__(
         cls.final_states: List[State] = [state for state in cls.states if state.final]
 
         cls._check()
+        cls._setup()
 
     if TYPE_CHECKING:
         """Makes mypy happy with dynamic created attributes"""
@@ -148,6 +151,23 @@ def _check_disconnected_state(cls):
                 ).format([s.id for s in disconnected_states])
             )
 
+    def _setup(cls):
+        for visited in iterate_states_and_transitions(cls.states):
+            visited._setup()
+
+        cls._protected_attrs = {
+            "_abstract",
+            "model",
+            "state_field",
+            "start_value",
+            "initial_state",
+            "final_states",
+            "states",
+            "_events",
+            "states_map",
+            "send",
+        } | {s.id for s in cls.states}
+
     def add_inherited(cls, bases):
         for base in bases:
             for state in getattr(base, "states", []):

statemachine/factory.py

@@ -12,3 +12,9 @@ def visit_connected_states(state):
         already_visited.add(state)
         yield state
         visit.extend(t.target for t in state.transitions)
+
+
+def iterate_states_and_transitions(states):
+    for state in states:
+        yield state
+        yield from state.transitions

statemachine/graph.py

@@ -5,6 +5,8 @@
 from typing import Any
 from typing import Dict
 
+from statemachine.graph import iterate_states_and_transitions
+
 from .callbacks import CallbackMetaList
 from .callbacks import CallbacksExecutor
 from .callbacks import CallbacksRegistry
@@ -81,7 +83,7 @@ def __init__(
         if self._abstract:
             raise InvalidDefinition(_("There are no states or transitions."))
 
-        self._setup()
+        self._register_callbacks()
         self._activate_initial_state()
 
     def __init_subclass__(cls, strict_states: bool = False):
@@ -109,7 +111,7 @@ def __deepcopy__(self, memo):
             self.__deepcopy__ = deepcopy_method
             cp.__deepcopy__ = deepcopy_method
         cp._callbacks_registry.clear()
-        cp._setup()
+        cp._register_callbacks()
         cp.add_observer(*cp._observers.keys())
         return cp
 
@@ -138,38 +140,16 @@ def _activate_initial_state(self):
             )
             self._activate(event_data)
 
-    def _get_protected_attrs(self):
-        return {
-            "_abstract",
-            "model",
-            "state_field",
-            "start_value",
-            "initial_state",
-            "final_states",
-            "states",
-            "_events",
-            "states_map",
-            "send",
-        } | {s.id for s in self.states}
-
-    def _iterate_states_and_transitions(self):
-        for state in self.states:
-            yield state
-            yield from state.transitions
-
-    def _setup(self):
-        for visited in self._iterate_states_and_transitions():
-            visited._setup()
-
+    def _register_callbacks(self):
         self._add_observer(
             (
-                ObjectConfig.from_obj(self, skip_attrs=self._get_protected_attrs()),
+                ObjectConfig.from_obj(self, skip_attrs=self._protected_attrs),
                 ObjectConfig.from_obj(self.model, skip_attrs={self.state_field}),
             )
         )
 
         check_callbacks = self._callbacks_registry.check
-        for visited in self._iterate_states_and_transitions():
+        for visited in iterate_states_and_transitions(self.states):
             try:
                 visited._check_callbacks(check_callbacks)
             except Exception as err:
@@ -179,7 +159,7 @@ def _setup(self):
 
     def _add_observer(self, observers):
         register = partial(self._callbacks_registry.register, resolver=resolver_factory(observers))
-        for visited in self._iterate_states_and_transitions():
+        for visited in iterate_states_and_transitions(self.states):
             visited._add_observer(register)
 
         return self