Merge master into feature-asyncio

Author: sveinse

canopen/__init__.py

@@ -1,8 +1,14 @@
 from canopen.network import Network, NodeScanner
-from canopen.node import RemoteNode, LocalNode
-from canopen.sdo import SdoCommunicationError, SdoAbortedError
-from canopen.objectdictionary import import_od, export_od, ObjectDictionary, ObjectDictionaryError
+from canopen.node import LocalNode, RemoteNode
+from canopen.objectdictionary import (
+    ObjectDictionary,
+    ObjectDictionaryError,
+    export_od,
+    import_od,
+)
 from canopen.profiles.p402 import BaseNode402
+from canopen.sdo import SdoAbortedError, SdoCommunicationError
+
 try:
     from canopen._version import version as __version__
 except ImportError:

canopen/emcy.py

@@ -1,14 +1,13 @@
-import struct
+import asyncio
 import logging
+import struct
 import threading
-import asyncio
 import time
-from typing import Callable, List, Optional, TYPE_CHECKING
+from typing import Callable, List, Optional
 
 from canopen.async_guard import ensure_not_async
+import canopen.network
 
-if TYPE_CHECKING:
-    from canopen.network import Network
 
 # Error code, error register, vendor specific data
 EMCY_STRUCT = struct.Struct("<HB5s")
@@ -117,7 +116,7 @@ def wait(
 class EmcyProducer:
 
     def __init__(self, cob_id: int):
-        self.network: Optional[Network] = None
+        self.network: canopen.network.Network = canopen.network._UNINITIALIZED_NETWORK
         self.cob_id = cob_id
 
     def send(self, code: int, register: int = 0, data: bytes = b""):

canopen/lss.py

@@ -1,14 +1,13 @@
-from typing import Optional, TYPE_CHECKING
+import asyncio
 import logging
-import time
-import struct
 import queue
-import asyncio
+import struct
+import time
+from typing import Optional, TYPE_CHECKING
 
 from canopen.async_guard import ensure_not_async
+import canopen.network
 
-if TYPE_CHECKING:
-    from canopen.network import Network
 
 logger = logging.getLogger(__name__)
 
@@ -85,8 +84,8 @@ class LssMaster:
     #: Max time in seconds to wait for response from server
     RESPONSE_TIMEOUT = 0.5
 
-    def __init__(self):
-        self.network: Optional[Network] = None
+    def __init__(self) -> None:
+        self.network: canopen.network.Network = canopen.network._UNINITIALIZED_NETWORK
         self._node_id = 0
         self._data = None
         self.responses = queue.Queue()

canopen/network.py

@@ -1,26 +1,23 @@
 from __future__ import annotations
-from collections.abc import MutableMapping
+
+import asyncio
 import logging
 import threading
-from typing import Callable, Dict, Iterator, List, Optional, Union, TYPE_CHECKING
-import asyncio
-
-if TYPE_CHECKING:
-    from can import BusABC, Notifier
-    from asyncio import AbstractEventLoop
+from collections.abc import MutableMapping
+from typing import Callable, Dict, Final, Iterator, List, Optional, Union
 
 import can
 from can import Listener
-from can import CanError
 
-from canopen.node import RemoteNode, LocalNode
-from canopen.sync import SyncProducer
-from canopen.timestamp import TimeProducer
-from canopen.nmt import NmtMaster
+from canopen.async_guard import set_async_sentinel
 from canopen.lss import LssMaster
-from canopen.objectdictionary.eds import import_from_node
+from canopen.nmt import NmtMaster
+from canopen.node import LocalNode, RemoteNode
 from canopen.objectdictionary import ObjectDictionary
-from canopen.async_guard import set_async_sentinel
+from canopen.objectdictionary.eds import import_from_node
+from canopen.sync import SyncProducer
+from canopen.timestamp import TimeProducer
+
 
 logger = logging.getLogger(__name__)
 
@@ -34,7 +31,7 @@ class Network(MutableMapping):
     NOTIFIER_SHUTDOWN_TIMEOUT: float = 5.0  #: Maximum waiting time to stop notifiers.
 
     def __init__(self, bus: Optional[can.BusABC] = None, notifier: Optional[can.Notifier] = None,
-                 loop: Optional[AbstractEventLoop] = None):
+                 loop: Optional[asyncio.AbstractEventLoop] = None):
         """
         :param can.BusABC bus:
             A python-can bus instance to re-use.
@@ -314,6 +311,21 @@ def __len__(self) -> int:
         return len(self.nodes)
 
 
+class _UninitializedNetwork(Network):
+    """Empty network implementation as a placeholder before actual initialization."""
+
+    def __init__(self, bus: Optional[can.BusABC] = None):
+        """Do not initialize attributes, by skipping the parent constructor."""
+
+    def __getattribute__(self, name):
+        raise RuntimeError("No actual Network object was assigned, "
+                           "try associating to a real network first.")
+
+
+#: Singleton instance
+_UNINITIALIZED_NETWORK: Final[Network] = _UninitializedNetwork()
+
+
 class PeriodicMessageTask:
     """
     Task object to transmit a message periodically using python-can's

canopen/nmt.py

@@ -1,14 +1,15 @@
-import threading
+import asyncio
 import logging
 import struct
+import threading
 import time
-import asyncio
 from typing import Callable, Optional, TYPE_CHECKING
 
 from canopen.async_guard import ensure_not_async
+import canopen.network
 
 if TYPE_CHECKING:
-    from canopen.network import Network, PeriodicMessageTask
+    from canopen.network import PeriodicMessageTask
 
 
 logger = logging.getLogger(__name__)
@@ -52,7 +53,7 @@ class NmtBase:
 
     def __init__(self, node_id: int):
         self.id = node_id
-        self.network: Optional[Network] = None
+        self.network: canopen.network.Network = canopen.network._UNINITIALIZED_NETWORK
         self._state = 0
 
     def on_command(self, can_id, data, timestamp):

canopen/node/__init__.py

@@ -1,2 +1,2 @@
-from canopen.node.remote import RemoteNode
 from canopen.node.local import LocalNode
+from canopen.node.remote import RemoteNode

canopen/node/base.py

@@ -1,10 +1,8 @@
-from typing import TextIO, Union, Optional, TYPE_CHECKING
+from typing import TextIO, Union
 
+import canopen.network
 from canopen.objectdictionary import ObjectDictionary, import_od
 
-if TYPE_CHECKING:
-    from canopen.network import Network
-
 
 class BaseNode:
     """A CANopen node.
@@ -21,7 +19,7 @@ def __init__(
         node_id: int,
         object_dictionary: Union[ObjectDictionary, str, TextIO],
     ):
-        self.network: Optional[Network] = None
+        self.network: canopen.network.Network = canopen.network._UNINITIALIZED_NETWORK
 
         if not isinstance(object_dictionary, ObjectDictionary):
             object_dictionary = import_od(object_dictionary, node_id)
@@ -30,3 +28,7 @@ def __init__(
         self.id = node_id or self.object_dictionary.node_id
 
     # FIXME: Should associate_network() and remove_network() be a part of the base API?
+
+    def has_network(self) -> bool:
+        """Check whether the node has been associated to a network."""
+        return not isinstance(self.network, canopen.network._UninitializedNetwork)

canopen/node/local.py

@@ -1,17 +1,17 @@
 from __future__ import annotations
+
 import logging
-from typing import Dict, Union, TYPE_CHECKING
+from typing import Dict, Union
 
-from canopen.node.base import BaseNode
-from canopen.sdo import SdoServer, SdoAbortedError
-from canopen.pdo import PDO, TPDO, RPDO
-from canopen.nmt import NmtSlave
+import canopen.network
+from canopen import objectdictionary
 from canopen.emcy import EmcyProducer
+from canopen.nmt import NmtSlave
+from canopen.node.base import BaseNode
 from canopen.objectdictionary import ObjectDictionary
-from canopen import objectdictionary
+from canopen.pdo import PDO, RPDO, TPDO
+from canopen.sdo import SdoAbortedError, SdoServer
 
-if TYPE_CHECKING:
-    from canopen.network import Network
 
 logger = logging.getLogger(__name__)
 
@@ -38,7 +38,7 @@ def __init__(
         self.add_write_callback(self.nmt.on_write)
         self.emcy = EmcyProducer(0x80 + self.id)
 
-    def associate_network(self, network: Network):
+    def associate_network(self, network: canopen.network.Network):
         self.network = network
         self.sdo.network = network
         self.tpdo.network = network
@@ -48,16 +48,15 @@ def associate_network(self, network: Network):
         network.subscribe(self.sdo.rx_cobid, self.sdo.on_request)
         network.subscribe(0, self.nmt.on_command)
 
-    def remove_network(self):
-        network = self.network
-        network.unsubscribe(self.sdo.rx_cobid, self.sdo.on_request)
-        network.unsubscribe(0, self.nmt.on_command)
-        self.network = None
-        self.sdo.network = None
-        self.tpdo.network = None
-        self.rpdo.network = None
-        self.nmt.network = None
-        self.emcy.network = None
+    def remove_network(self) -> None:
+        self.network.unsubscribe(self.sdo.rx_cobid, self.sdo.on_request)
+        self.network.unsubscribe(0, self.nmt.on_command)
+        self.network = canopen.network._UNINITIALIZED_NETWORK
+        self.sdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.tpdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.rpdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.nmt.network = canopen.network._UNINITIALIZED_NETWORK
+        self.emcy.network = canopen.network._UNINITIALIZED_NETWORK
 
     def add_read_callback(self, callback):
         self._read_callbacks.append(callback)

canopen/node/remote.py

@@ -1,16 +1,16 @@
 from __future__ import annotations
+
 import logging
-from typing import Union, TextIO, List, TYPE_CHECKING
+from typing import TextIO, Union, List
 
-from canopen.sdo import SdoClient, SdoCommunicationError, SdoAbortedError
-from canopen.nmt import NmtMaster
+import canopen.network
 from canopen.emcy import EmcyConsumer
-from canopen.pdo import TPDO, RPDO, PDO
-from canopen.objectdictionary import ODRecord, ODArray, ODVariable, ObjectDictionary
+from canopen.nmt import NmtMaster
 from canopen.node.base import BaseNode
+from canopen.objectdictionary import ODArray, ODRecord, ODVariable, ObjectDictionary
+from canopen.pdo import PDO, RPDO, TPDO
+from canopen.sdo import SdoAbortedError, SdoClient, SdoCommunicationError
 
-if TYPE_CHECKING:
-    from canopen.network import Network
 
 logger = logging.getLogger(__name__)
 
@@ -50,7 +50,7 @@ def __init__(
         if load_od:
             self.load_configuration()
 
-    def associate_network(self, network: Network):
+    def associate_network(self, network: canopen.network.Network):
         self.network = network
         self.sdo.network = network
         self.pdo.network = network
@@ -67,23 +67,22 @@ def associate_network(self, network: Network):
             network.subscribe(0x80 + self.id, self.emcy.on_emcy)
         network.subscribe(0, self.nmt.on_command)
 
-    def remove_network(self):
-        network = self.network
+    def remove_network(self) -> None:
         for sdo in self.sdo_channels:
-            network.unsubscribe(sdo.tx_cobid, sdo.on_response)
-        if network.is_async():
-            network.unsubscribe(0x700 + self.id, self.nmt.aon_heartbeat)
-            network.unsubscribe(0x80 + self.id, self.emcy.aon_emcy)
+            self.network.unsubscribe(sdo.tx_cobid, sdo.on_response)
+        if self.network.is_async():
+            self.network.unsubscribe(0x700 + self.id, self.nmt.aon_heartbeat)
+            self.network.unsubscribe(0x80 + self.id, self.emcy.aon_emcy)
         else:
-            network.unsubscribe(0x700 + self.id, self.nmt.on_heartbeat)
-            network.unsubscribe(0x80 + self.id, self.emcy.on_emcy)
-        network.unsubscribe(0, self.nmt.on_command)
-        self.network = None
-        self.sdo.network = None
-        self.pdo.network = None
-        self.tpdo.network = None
-        self.rpdo.network = None
-        self.nmt.network = None
+            self.network.unsubscribe(0x700 + self.id, self.nmt.on_heartbeat)
+            self.network.unsubscribe(0x80 + self.id, self.emcy.on_emcy)
+        self.network.unsubscribe(0, self.nmt.on_command)
+        self.network = canopen.network._UNINITIALIZED_NETWORK
+        self.sdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.pdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.tpdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.rpdo.network = canopen.network._UNINITIALIZED_NETWORK
+        self.nmt.network = canopen.network._UNINITIALIZED_NETWORK
 
     def add_sdo(self, rx_cobid, tx_cobid):
         """Add an additional SDO channel.
@@ -100,7 +99,7 @@ def add_sdo(self, rx_cobid, tx_cobid):
         """
         client = SdoClient(rx_cobid, tx_cobid, self.object_dictionary)
         self.sdo_channels.append(client)
-        if self.network is not None:
+        if self.has_network():
             self.network.subscribe(client.tx_cobid, client.on_response)
         return client
 

canopen/objectdictionary/__init__.py

@@ -1,17 +1,19 @@
 """
 Object Dictionary module
 """
+
 from __future__ import annotations
 
+import logging
 import struct
+from collections.abc import Mapping, MutableMapping
 from typing import Dict, Iterator, List, Optional, TextIO, Union
-from collections.abc import MutableMapping, Mapping
-import logging
 
 from canopen.objectdictionary.datatypes import *
 from canopen.objectdictionary.datatypes import IntegerN, UnsignedN
 from canopen.utils import pretty_index
 
+
 logger = logging.getLogger(__name__)