refac: Improved support for pickle and deepcopy

Author: fgmacedo

statemachine/engines/base.py

@@ -17,9 +17,19 @@ class BaseEngine:
     def __init__(self, sm: "StateMachine", rtc: bool = True):
         self.sm: StateMachine = proxy(sm)
         self._external_queue: deque = deque()
+        self._processing = Lock()
         self._sentinel = object()
         self._rtc = rtc
-        self._processing = Lock()
+
+    def __getstate__(self) -> dict:
+        state = self.__dict__.copy()
+        del state["_external_queue"]
+        del state["_processing"]
+        del state["sm"]
+        return state
+
+    def __setstate__(self, state: dict) -> None:
+        self.__dict__.update(state)
 
     def put(self, trigger_data: TriggerData):
         """Put the trigger on the queue without blocking the caller."""

statemachine/statemachine.py

@@ -1,7 +1,5 @@
 import warnings
-from copy import deepcopy
 from inspect import isawaitable
-from threading import Lock
 from typing import TYPE_CHECKING
 from typing import Any
 from typing import Dict
@@ -129,24 +127,6 @@ def __repr__(self):
             f"current_state={current_state_id!r})"
         )
 
-    def __deepcopy__(self, memo):
-        deepcopy_method = self.__deepcopy__
-        lock = self._engine._processing
-        with lock:
-            self.__deepcopy__ = None
-            self._engine._processing = None
-            try:
-                cp = deepcopy(self, memo)
-                cp._engine._processing = Lock()
-            finally:
-                self.__deepcopy__ = deepcopy_method
-                cp.__deepcopy__ = deepcopy_method
-                self._engine._processing = lock
-        cp._callbacks.clear()
-        cp._register_callbacks([])
-        cp.add_listener(*cp._listeners.keys())
-        return cp
-
     def __getstate__(self):
         state = self.__dict__.copy()
         state["_rtc"] = self._engine._rtc