Specific Exceptions: Adapting pcan interface

Part of #1046.

Also partly cleans up the docstrings in `basic.py` and uses some subtests in `test_pcan.py` (the parameter `name` was else unused in most parameterized tests).

Author: felixdivo

can/interfaces/pcan/basic.py

@@ -8,17 +8,12 @@
 #
 #  ------------------------------------------------------------------
 #  Author : Keneth Wagner
-#  Last change: 14.01.2021 Wagner
-#
-#  Language: Python 2.7, 3.7
 #  ------------------------------------------------------------------
 #
 #  Copyright (C) 1999-2021  PEAK-System Technik GmbH, Darmstadt
 #  more Info at http://www.peak-system.com
-#
 
 # Module Imports
-#
 from ctypes import *
 from ctypes.util import find_library
 from string import *
@@ -601,8 +596,7 @@ def Initialize(
         Interrupt=c_ushort(0),
     ):
 
-        """
-          Initializes a PCAN Channel
+        """Initializes a PCAN Channel
 
         Parameters:
           Channel  : A TPCANHandle representing a PCAN Channel
@@ -627,8 +621,7 @@ def Initialize(
     #
     def InitializeFD(self, Channel, BitrateFD):
 
-        """
-          Initializes a FD capable PCAN Channel
+        """Initializes a FD capable PCAN Channel
 
         Parameters:
           Channel  : The handle of a FD capable PCAN Channel
@@ -659,8 +652,7 @@ def InitializeFD(self, Channel, BitrateFD):
     #
     def Uninitialize(self, Channel):
 
-        """
-          Uninitializes one or all PCAN Channels initialized by CAN_Initialize
+        """Uninitializes one or all PCAN Channels initialized by CAN_Initialize
 
         Remarks:
           Giving the TPCANHandle value "PCAN_NONEBUS", uninitialize all initialized channels
@@ -682,8 +674,7 @@ def Uninitialize(self, Channel):
     #
     def Reset(self, Channel):
 
-        """
-          Resets the receive and transmit queues of the PCAN Channel
+        """Resets the receive and transmit queues of the PCAN Channel
 
         Remarks:
           A reset of the CAN controller is not performed
@@ -705,8 +696,7 @@ def Reset(self, Channel):
     #
     def GetStatus(self, Channel):
 
-        """
-          Gets the current status of a PCAN Channel
+        """Gets the current status of a PCAN Channel
 
         Parameters:
           Channel  : A TPCANHandle representing a PCAN Channel
@@ -725,8 +715,7 @@ def GetStatus(self, Channel):
     #
     def Read(self, Channel):
 
-        """
-          Reads a CAN message from the receive queue of a PCAN Channel
+        """Reads a CAN message from the receive queue of a PCAN Channel
 
         Remarks:
           The return value of this method is a 3-touple, where
@@ -740,7 +729,7 @@ def Read(self, Channel):
           Channel  : A TPCANHandle representing a PCAN Channel
 
         Returns:
-          A touple with three values
+          A tuple with three values
         """
         try:
             msg = TPCANMsg()
@@ -755,8 +744,7 @@ def Read(self, Channel):
     #
     def ReadFD(self, Channel):
 
-        """
-          Reads a CAN message from the receive queue of a FD capable PCAN Channel
+        """Reads a CAN message from the receive queue of a FD capable PCAN Channel
 
         Remarks:
           The return value of this method is a 3-touple, where
@@ -770,7 +758,7 @@ def ReadFD(self, Channel):
           Channel  : The handle of a FD capable PCAN Channel
 
         Returns:
-          A touple with three values
+          A tuple with three values
         """
         try:
             msg = TPCANMsgFD()
@@ -785,8 +773,7 @@ def ReadFD(self, Channel):
     #
     def Write(self, Channel, MessageBuffer):
 
-        """
-          Transmits a CAN message
+        """Transmits a CAN message
 
         Parameters:
           Channel      : A TPCANHandle representing a PCAN Channel
@@ -806,8 +793,7 @@ def Write(self, Channel, MessageBuffer):
     #
     def WriteFD(self, Channel, MessageBuffer):
 
-        """
-          Transmits a CAN message over a FD capable PCAN Channel
+        """Transmits a CAN message over a FD capable PCAN Channel
 
         Parameters:
           Channel      : The handle of a FD capable PCAN Channel
@@ -827,8 +813,7 @@ def WriteFD(self, Channel, MessageBuffer):
     #
     def FilterMessages(self, Channel, FromID, ToID, Mode):
 
-        """
-          Configures the reception filter
+        """Configures the reception filter
 
         Remarks:
           The message filter will be expanded with every call to this function.
@@ -855,8 +840,7 @@ def FilterMessages(self, Channel, FromID, ToID, Mode):
     #
     def GetValue(self, Channel, Parameter):
 
-        """
-          Retrieves a PCAN Channel value
+        """Retrieves a PCAN Channel value
 
         Remarks:
           Parameters can be present or not according with the kind
@@ -872,7 +856,7 @@ def GetValue(self, Channel, Parameter):
           Parameter : The TPCANParameter parameter to get
 
         Returns:
-          A touple with 2 values
+          A tuple with 2 values
         """
         try:
             if (
@@ -912,9 +896,8 @@ def GetValue(self, Channel, Parameter):
     #
     def SetValue(self, Channel, Parameter, Buffer):
 
-        """
-          Returns a descriptive text of a given TPCANStatus error
-          code, in any desired language
+        """Returns a descriptive text of a given TPCANStatus error
+        code, in any desired language
 
         Remarks:
           Parameters can be present or not according with the kind
@@ -951,8 +934,7 @@ def SetValue(self, Channel, Parameter, Buffer):
 
     def GetErrorText(self, Error, Language=0):
 
-        """
-          Configures or sets a PCAN Channel value
+        """Configures or sets a PCAN Channel value
 
         Remarks:
 
@@ -969,7 +951,7 @@ def GetErrorText(self, Error, Language=0):
           Language : Indicates a 'Primary language ID' (Default is Neutral(0))
 
         Returns:
-          A touple with 2 values
+          A tuple with 2 values
         """
         try:
             mybuffer = create_string_buffer(256)
@@ -981,8 +963,7 @@ def GetErrorText(self, Error, Language=0):
 
     def LookUpChannel(self, Parameters):
 
-        """
-            Finds a PCAN-Basic channel that matches with the given parameters
+        """Finds a PCAN-Basic channel that matches with the given parameters
 
         Remarks:
 
@@ -995,7 +976,7 @@ def LookUpChannel(self, Parameters):
                            to be matched within a PCAN-Basic channel
 
         Returns:
-          A touple with 2 values
+          A tuple with 2 values
         """
         try:
             mybuffer = TPCANHandle(0)

can/interfaces/pcan/pcan.py

@@ -2,15 +2,18 @@
 Enable basic CAN over a PCAN USB device.
 """
 
+from .basic import *  # Do this first since the wildcard imports a lot
+
 import logging
 import time
 from datetime import datetime
 
 from typing import Optional
-from can import CanError, Message, BusABC
-from can.bus import BusState
-from can.util import len2dlc, dlc2len
-from .basic import *
+
+from ...message import Message
+from ...bus import BusABC, BusState
+from ...util import len2dlc, dlc2len
+from ...exceptions import CanError, CanOperationError, CanInitializationError
 
 
 # Set up logging
@@ -251,7 +254,7 @@ def __init__(
         ioport = 0x02A0
         interrupt = 11
 
-        if type(channel) != int:
+        if not isinstance(channel, int):
             channel = pcan_channel_names[channel]
 
         self.m_objPCANBasic = PCANBasic()
@@ -260,7 +263,7 @@ def __init__(
         if state is BusState.ACTIVE or state is BusState.PASSIVE:
             self.state = state
         else:
-            raise ArgumentError("BusState must be Active or Passive")
+            raise ValueError("BusState must be Active or Passive")
 
         if self.fd:
             f_clock_val = kwargs.get("f_clock", None)
@@ -286,15 +289,15 @@ def __init__(
             )
 
         if result != PCAN_ERROR_OK:
-            raise PcanError(self._get_formatted_error(result))
+            raise PcanCanInitializationError(self._get_formatted_error(result))
 
         result = self.m_objPCANBasic.SetValue(
             self.m_PcanHandle, PCAN_ALLOW_ERROR_FRAMES, PCAN_PARAMETER_ON
         )
 
         if result != PCAN_ERROR_OK:
             if platform.system() != "Darwin":
-                raise PcanError(self._get_formatted_error(result))
+                raise PcanCanInitializationError(self._get_formatted_error(result))
             else:
                 # TODO Remove Filter when MACCan actually supports it:
                 #  https://github.com/mac-can/PCBUSB-Library/
@@ -308,7 +311,7 @@ def __init__(
                 self.m_PcanHandle, PCAN_RECEIVE_EVENT, self._recv_event
             )
             if result != PCAN_ERROR_OK:
-                raise PcanError(self._get_formatted_error(result))
+                raise PcanCanInitializationError(self._get_formatted_error(result))
 
         super().__init__(channel=channel, state=state, bitrate=bitrate, *args, **kwargs)
 
@@ -407,7 +410,7 @@ def set_device_number(self, device_number):
                 )
                 != PCAN_ERROR_OK
             ):
-                raise ValueError
+                raise ValueError()
         except ValueError:
             log.error("Invalid value '%s' for device number.", device_number)
             return False
@@ -445,7 +448,7 @@ def _recv_internal(self, timeout):
                 log.warning(self._get_formatted_error(result[0]))
                 return None, False
             elif result[0] != PCAN_ERROR_OK:
-                raise PcanError(self._get_formatted_error(result[0]))
+                raise PcanCanOperationError(self._get_formatted_error(result[0]))
 
         theMsg = result[1]
         itsTimeStamp = result[2]
@@ -554,7 +557,7 @@ def send(self, msg, timeout=None):
             result = self.m_objPCANBasic.Write(self.m_PcanHandle, CANMsg)
 
         if result != PCAN_ERROR_OK:
-            raise PcanError("Failed to send: " + self._get_formatted_error(result))
+            raise PcanCanOperationError("Failed to send: " + self._get_formatted_error(result))
 
     def flash(self, flash):
         """
@@ -655,6 +658,12 @@ def status_string(self) -> Optional[str]:
 
 
 class PcanError(CanError):
-    """
-    A generic error on a PCAN bus.
-    """
+    """A generic error on a PCAN bus."""
+
+
+class PcanCanOperationError(CanOperationError, PcanError):
+    """Like :class:`can.exceptions.CanOperationError`, but specific to Pcan."""
+
+
+class PcanCanInitializationError(CanInitializationError, PcanError):
+    """Like :class:`can.exceptions.CanInitializationError`, but specific to Pcan."""