Merge pull request #110 from khauersp/feature/improve-ma

Improve some memory access functionality

Author: snideto

j1939/Dm14Query.py

@@ -45,6 +45,33 @@ def __init__(self, ca: j1939.ControllerApplication, user_level=7) -> None:
         self.exception_queue = queue.Queue()
         self.user_level = user_level
 
+    def unsubscribe_all(self) -> None:
+        """
+        Unsubscribes all message handlers
+        """
+        self._ca.unsubscribe(self._parse_dm15)
+        self._ca.unsubscribe(self._parse_dm16)
+        
+    def reset_query(self) -> None:
+        """
+        Resets query to remove transaction specific data
+        """
+        self.state = QueryState.IDLE
+        self._dest_address = None
+        self.address = None
+        self.object_count = 0
+        self.object_byte_size = 1
+        self.signed = False
+        self.return_raw_bytes = False
+        self.direct = 0
+        self.command = None
+        self.bytes = bytearray()
+        self.mem_data = None
+        self.data_queue = queue.Queue()
+        self.exception_queue = queue.Queue()
+        self.unsubscribe_all()
+
+
     def _wait_for_data(self) -> None:
         """
         Determines whether to send data or wait to receive data based on the command type. If the command is a write command, then the data is sent.

j1939/Dm14Server.py

@@ -161,11 +161,10 @@ def parse_dm14(
                 self.state = ResponseState.SEND_PROCEED
 
             case ResponseState.WAIT_OPERATION_COMPLETE:
-                self.state = ResponseState.IDLE
-                self.sa = None
-                self._ca.unsubscribe(self.parse_dm14)
+                self.reset_server()
 
             case _:
+                self.reset_server()
                 raise ValueError("Invalid state")
 
     def _send_dm15(
@@ -222,6 +221,7 @@ def _send_dm15(
                 data[length - 3] = edcp
 
             case _:
+                self.reset_server()
                 raise ValueError("Invalid state")
         self._ca.send_pgn(0, (pgn >> 8) & 0xFF, sa & 0xFF, 6, data)
 
@@ -255,12 +255,12 @@ def _parse_dm16(
 
         if pgn != j1939.ParameterGroupNumber.PGN.DM16 or sa != self.sa:
             return
-
         length = min(data[0], len(data) - 1)
         self.data_queue.put(data[1 : length + 1])
         self._ca.unsubscribe(self._parse_dm16)
         self._ca.subscribe(self.parse_dm14)
         self.state = ResponseState.SEND_OPERATION_COMPLETE
+
         self._send_dm15(
             self.length,
             self.direct,
@@ -329,11 +329,19 @@ def verify_key(self, seed: int, key: int) -> bool:
             )
         return self._key_from_seed(seed) == key
 
-    def reset_query(self) -> None:
+    def unsubscribe_all(self) -> None:
+        """
+        Unsubscribes all message handlers
+        """
+        self._ca.unsubscribe(self.parse_dm14)
+        self._ca.unsubscribe(self._parse_dm16)
+
+    def reset_server(self) -> None:
         """
-        Resets query to initial state
+        Resets server to remove transaction specific data
         """
         self.state = ResponseState.IDLE
+        self.data_queue = queue.Queue()
         self.sa = None
         self.seed = None
         self.key = None
@@ -346,8 +354,7 @@ def reset_query(self) -> None:
         self.edcp = 0x07
         self.status = j1939.Dm15Status.PROCEED.value
         self.direct = 0
-        self._ca.unsubscribe(self.parse_dm14)
-        self._ca.unsubscribe(self._parse_dm16)
+        self.unsubscribe_all()
 
     def respond(
         self,

j1939/electronic_control_unit.py

@@ -374,7 +374,10 @@ def _notify_subscribers(self, priority, pgn, sa, dest, timestamp, data):
         logger.debug("notify subscribers for PGN {}".format(pgn))
         # notify only the CA for which the message is intended
         # each CA receives all broadcast messages
-        for dic in self._subscribers:
+
+        # TODO: this is ineffecient but there exists a possibility of removing subscribers during callback
+        # and adding new ones in while this is going and it can impact message receivement
+        for dic in self._subscribers.copy():
             if (dic['dev_adr'] == None) or (dest == ParameterGroupNumber.Address.GLOBAL) or (callable(dic['dev_adr']) and dic['dev_adr'](dest)) or (dest == dic['dev_adr']):
                 dic['cb'](priority, pgn, sa, timestamp, data)
 

j1939/memory_access.py

@@ -7,12 +7,14 @@ class DMState(Enum):
     REQUEST_STARTED = 2
     WAIT_RESPONSE = 3
     WAIT_QUERY = 4
+    SERVER_CLEANUP = 5
 
 
 class MemoryAccess:
     def __init__(self, ca: j1939.ControllerApplication) -> None:
         """
         Makes an overarching Memory access class
+
         :param ca: Controller Application
         """
         self._ca = ca
@@ -22,14 +24,33 @@ def __init__(self, ca: j1939.ControllerApplication) -> None:
         self.state = DMState.IDLE
         self.seed_security = False
         self._notify_query_received = None
-        self._seed_key_valid = None
         self._proceed_function = None
 
+    def _handle_error(self, priority: int, pgn: int, sa: int, timestamp: int, data: bytearray, error_code: int) -> None:
+        """
+        Handles errors by resetting the state and unsubscribing from DM14 messages
+
+        :param priority: Priority of the message
+        :param pgn: Parameter Group Number of the message
+        :param sa: Source Address of the message
+        :param timestamp: Timestamp of the message
+        :param data: Data of the PDU
+        :param error_code: Error code to be set
+        """
+        self.server.error = error_code
+        self.server.set_busy(True)
+        self.server.parse_dm14(
+            priority, pgn, sa, timestamp, data
+        )
+        self.server.set_busy(False)
+        self.reset()
+
     def _listen_for_dm14(
         self, priority: int, pgn: int, sa: int, timestamp: int, data: bytearray
     ) -> None:
         """
         Listens for dm14 messages and passes them to the appropriate function
+
         :param priority: Priority of the message
         :param pgn: Parameter Group Number of the message
         :param sa: Source Address of the message
@@ -64,15 +85,7 @@ def _listen_for_dm14(
                                 if self.proceed:
                                     self._notify_query_received()  # notify incoming request
                                 else:
-                                    self.server.error = 0x100
-                                    self.server.set_busy(True)
-                                    self.server.parse_dm14(
-                                        priority, pgn, sa, timestamp, data
-                                    )
-                                    self.server.set_busy(False)
-                                    self.server.reset_query()
-                                    self.state = DMState.IDLE
-                                    self.server.error = 0x0
+                                    self._handle_error(priority, pgn, sa, timestamp, data, 0x100)
 
                 case DMState.REQUEST_STARTED:
                     self.server.parse_dm14(priority, pgn, sa, timestamp, data)
@@ -101,32 +114,19 @@ def _listen_for_dm14(
                                     if self.proceed:
                                         self._notify_query_received()  # notify incoming request
                                     else:
-                                        self.server.error = 0x100
-                                        self.server.set_busy(True)
-                                        self.server.parse_dm14(
-                                            priority, pgn, sa, timestamp, data
-                                        )
-                                        self.server.set_busy(False)
-                                        self.server.reset_query()
-                                        self.state = DMState.IDLE
-                                        self.server.error = 0x0
+                                        self._handle_error(priority, pgn, sa, timestamp, data, 0x100)
                             else:
-                                self.server.error = 0x1003
-                                self.server.set_busy(True)
-                                self.server.parse_dm14(
-                                    priority, pgn, sa, timestamp, data
-                                )
-                                self.server.set_busy(False)
-                                self.state = DMState.IDLE
-                                self.server.error = 0x0
+                                self._handle_error(priority, pgn, sa, timestamp, data, 0x1003)
 
                 case DMState.WAIT_QUERY:
                     self.server.set_busy(True)
                     self.server.parse_dm14(priority, pgn, sa, timestamp, data)
                     self.server.set_busy(False)
+                case DMState.SERVER_CLEANUP:
+                    self.state = DMState.IDLE
                 case _:
                     pass
-
+        
     def respond(
         self,
         proceed: bool,
@@ -137,6 +137,7 @@ def respond(
     ) -> list:
         """
         Responds with requested data and error code, if applicable, to a read request
+
         :param bool proceed: whether the operation is good to proceed
         :param list data: data to be sent to device
         :param int error: error code to be sent to device
@@ -145,14 +146,15 @@ def respond(
         """
         if data is None:
             data = []
-        if self.state is DMState.WAIT_RESPONSE:
-            self._ca.unsubscribe(self._listen_for_dm14)
-            self.state = DMState.IDLE
-            return_data = self.server.respond(proceed, data, error, edcp, max_timeout)
-            self._ca.subscribe(self._listen_for_dm14)
-            return return_data
-        else:
+        
+        if self.state is not DMState.WAIT_RESPONSE:
             return data
+        
+        self._ca.unsubscribe(self._listen_for_dm14)
+        return_data = self.server.respond(proceed, data, error, edcp, max_timeout)
+        self.state = DMState.SERVER_CLEANUP if self.server.state.value != DMState.IDLE.value else DMState.IDLE
+        self._ca.subscribe(self._listen_for_dm14)
+        return return_data
 
     def read(
         self,
@@ -167,6 +169,7 @@ def read(
     ) -> list:
         """
         Make a dm14 read Query
+
         :param int dest_address: destination address of the message
         :param int direct: direct address of the message
         :param int address: address of the message
@@ -189,9 +192,10 @@ def read(
                 return_raw_bytes,
                 max_timeout,
             )
-            self.state = DMState.IDLE
+            self.reset()
             return data
         else:
+            self.reset()
             raise RuntimeWarning("Process already Running")
 
     def write(
@@ -205,6 +209,7 @@ def write(
     ) -> None:
         """
         Send a write query to dest_address, requesting to write values at address
+
         :param int dest_address: destination address of the message
         :param int direct: direct address of the message
         :param int address: address of the message
@@ -218,7 +223,7 @@ def write(
             self.query.write(
                 dest_address, direct, address, values, object_byte_size, max_timeout
             )
-            self.state = DMState.IDLE
+            self.reset()
 
     def set_seed_generator(self, seed_generator: callable) -> None:
         """
@@ -229,7 +234,8 @@ def set_seed_generator(self, seed_generator: callable) -> None:
 
     def set_seed_key_algorithm(self, algorithm: callable) -> None:
         """
-        set seed-key algorithm to be used for key generation
+        Sets seed-key algorithm to be used for key generation
+
         :param callable algorithm: seed-key algorithm
         """
         self.seed_security = True
@@ -238,28 +244,34 @@ def set_seed_key_algorithm(self, algorithm: callable) -> None:
 
     def set_verify_key(self, verify_key: callable) -> None:
         """
-        set verify key function to be used for verifying the key
+        Sets verify key function to be used for verifying the key
+
         :param callable verify_key: verify key function
         """
         self.server.set_verify_key(verify_key)
 
     def set_notify(self, notify: callable) -> None:
         """
-        set notify function to be used for notifying the user of memory accesses
+        Sets notify function to be used for notifying the user of memory accesses
+
         :param callable notify: notify function
         """
         self._notify_query_received = notify
 
     def set_proceed(self, proceed: callable) -> None:
         """
-        set proceed function to determine if a memory query is valid or not
+        Sets proceed function to determine if a memory query is valid or not
+
         :param callable proceed: proceed function
         """
         self._proceed_function = proceed
 
-    def reset_query(self) -> None:
+    def reset(self) -> None:
         """
-        reset query for the server
+        Resets both server and query to remove transaction specific data
         """
+        self.state = DMState.IDLE
+        self._ca.unsubscribe(self._listen_for_dm14)
         self._ca.subscribe(self._listen_for_dm14)
-        self.server.reset_query()
+        self.server.reset_server()
+        self.query.reset_query()

test/test_ecu.py

@@ -200,3 +200,25 @@ def test_add_bus_filters(feeder):
     ]
     feeder.ecu.add_bus_filters(filters)
     assert feeder.ecu._bus.filters == filters
+
+def test_subscribe(feeder):
+    """
+    Test subscribing to callback
+    """
+    call_count = 0
+
+    def callback(priority: int, pgn: int, sa: int, timestamp: int, data: bytearray):
+        nonlocal call_count
+        call_count += 1
+
+    feeder.ecu.subscribe(callback)
+    
+    feeder.can_messages = [
+        (Feeder.MsgType.CANRX, 0x00FEB201, [1, 2, 3, 4, 5, 6, 7, 8], 0.0),
+    ]
+
+    feeder.pdus = [(Feeder.MsgType.PDU, 65202, [1, 2, 3, 4, 5, 6, 7, 8])]
+
+    feeder.receive()
+
+    assert call_count == 1