Improve IO typing

can/__init__.py

@@ -24,13 +24,6 @@
     CanTimeoutError,
 )
 
-from .io import Logger, SizedRotatingLogger, Printer, LogReader, MessageSync
-from .io import ASCWriter, ASCReader
-from .io import BLFReader, BLFWriter
-from .io import CanutilsLogReader, CanutilsLogWriter
-from .io import CSVWriter, CSVReader
-from .io import SqliteWriter, SqliteReader
-
 from .util import set_logging_level
 
 from .message import Message
@@ -42,6 +35,13 @@
 from .interface import Bus, detect_available_configs
 from .bit_timing import BitTiming
 
+from .io import Logger, SizedRotatingLogger, Printer, LogReader, MessageSync
+from .io import ASCWriter, ASCReader
+from .io import BLFReader, BLFWriter
+from .io import CanutilsLogReader, CanutilsLogWriter
+from .io import CSVWriter, CSVReader
+from .io import SqliteWriter, SqliteReader
+
 from .broadcastmanager import (
     CyclicSendTaskABC,
     LimitedDurationCyclicSendTaskABC,

can/io/asc.py

@@ -12,12 +12,10 @@
 import time
 import logging
 
-from .. import typechecking
 from ..message import Message
-from ..listener import Listener
 from ..util import channel2int
-from .generic import BaseIOHandler, FileIOMessageWriter
-from ..typechecking import AcceptedIOType
+from .generic import FileIOMessageWriter, MessageReader
+from ..typechecking import StringPathLike
 
 
 CAN_MSG_EXT = 0x80000000
@@ -28,7 +26,7 @@
 logger = logging.getLogger("can.io.asc")
 
 
-class ASCReader(BaseIOHandler):
+class ASCReader(MessageReader):
     """
     Iterator of CAN messages from a ASC logging file. Meta data (comments,
     bus statistics, J1939 Transport Protocol messages) is ignored.
@@ -40,7 +38,7 @@ class ASCReader(BaseIOHandler):
 
     def __init__(
         self,
-        file: AcceptedIOType,
+        file: Union[StringPathLike, TextIO],
         base: str = "hex",
         relative_timestamp: bool = True,
     ) -> None:
@@ -248,7 +246,7 @@ def __iter__(self) -> Generator[Message, None, None]:
         self.stop()
 
 
-class ASCWriter(FileIOMessageWriter, Listener):
+class ASCWriter(FileIOMessageWriter):
     """Logs CAN data to an ASCII log file (.asc).
 
     The measurement starts with the timestamp of the first registered message.
@@ -287,7 +285,7 @@ class ASCWriter(FileIOMessageWriter, Listener):
 
     def __init__(
         self,
-        file: AcceptedIOType,
+        file: Union[StringPathLike, TextIO],
         channel: int = 1,
     ) -> None:
         """

can/io/blf.py

@@ -17,13 +17,12 @@
 import datetime
 import time
 import logging
-from typing import List, BinaryIO
+from typing import List, BinaryIO, Generator, Union
 
 from ..message import Message
-from ..listener import Listener
 from ..util import len2dlc, dlc2len, channel2int
-from ..typechecking import AcceptedIOType
-from .generic import BaseIOHandler, FileIOMessageWriter
+from ..typechecking import StringPathLike
+from .generic import FileIOMessageWriter, MessageReader
 
 
 class BLFParseError(Exception):
@@ -131,7 +130,7 @@ def systemtime_to_timestamp(systemtime):
         return 0
 
 
-class BLFReader(BaseIOHandler):
+class BLFReader(MessageReader):
     """
     Iterator of CAN messages from a Binary Logging File.
 
@@ -141,7 +140,7 @@ class BLFReader(BaseIOHandler):
 
     file: BinaryIO
 
-    def __init__(self, file: AcceptedIOType) -> None:
+    def __init__(self, file: Union[StringPathLike, BinaryIO]) -> None:
         """
         :param file: a path-like object or as file-like object to read from
                      If this is a file-like object, is has to opened in binary
@@ -162,7 +161,7 @@ def __init__(self, file: AcceptedIOType) -> None:
         self._tail = b""
         self._pos = 0
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[Message, None, None]:
         while True:
             data = self.file.read(OBJ_HEADER_BASE_STRUCT.size)
             if not data:
@@ -349,7 +348,7 @@ def _parse_data(self, data):
             pos = next_pos
 
 
-class BLFWriter(FileIOMessageWriter, Listener):
+class BLFWriter(FileIOMessageWriter):
     """
     Logs CAN data to a Binary Logging File compatible with Vector's tools.
     """
@@ -364,7 +363,7 @@ class BLFWriter(FileIOMessageWriter, Listener):
 
     def __init__(
         self,
-        file: AcceptedIOType,
+        file: Union[StringPathLike, BinaryIO],
         append: bool = False,
         channel: int = 1,
         compression_level: int = -1,

can/io/canutils.py

@@ -5,11 +5,11 @@
 """
 
 import logging
+from typing import Generator, TextIO, Union
 
 from can.message import Message
-from can.listener import Listener
-from .generic import BaseIOHandler, FileIOMessageWriter
-from ..typechecking import AcceptedIOType
+from .generic import FileIOMessageWriter, MessageReader
+from ..typechecking import AcceptedIOType, StringPathLike
 
 log = logging.getLogger("can.io.canutils")
 
@@ -22,7 +22,7 @@
 CANFD_ESI = 0x02
 
 
-class CanutilsLogReader(BaseIOHandler):
+class CanutilsLogReader(MessageReader):
     """
     Iterator over CAN messages from a .log Logging File (candump -L).
 
@@ -32,30 +32,37 @@ class CanutilsLogReader(BaseIOHandler):
         ``(0.0) vcan0 001#8d00100100820100``
     """
 
-    def __init__(self, file: AcceptedIOType) -> None:
+    file: TextIO
+
+    def __init__(self, file: Union[StringPathLike, TextIO]) -> None:
         """
         :param file: a path-like object or as file-like object to read from
                      If this is a file-like object, is has to opened in text
                      read mode, not binary read mode.
         """
         super().__init__(file, mode="r")
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[Message, None, None]:
         for line in self.file:
 
             # skip empty lines
             temp = line.strip()
             if not temp:
                 continue
 
-            timestamp, channel, frame = temp.split()
-            timestamp = float(timestamp[1:-1])
-            canId, data = frame.split("#", maxsplit=1)
-            if channel.isdigit():
-                channel = int(channel)
+            channel_string: str
+            timestamp_string, channel_string, frame = temp.split()
+            timestamp = float(timestamp_string[1:-1])
+            can_id_string, data = frame.split("#", maxsplit=1)
+
+            channel: Union[int, str]
+            if channel_string.isdigit():
+                channel = int(channel_string)
+            else:
+                channel = channel_string
 
-            isExtended = len(canId) > 3
-            canId = int(canId, 16)
+            is_extended = len(can_id_string) > 3
+            can_id = int(can_id_string, 16)
 
             is_fd = False
             brs = False
@@ -69,43 +76,43 @@ def __iter__(self):
                 data = data[2:]
 
             if data and data[0].lower() == "r":
-                isRemoteFrame = True
+                is_remote_frame = True
 
                 if len(data) > 1:
                     dlc = int(data[1:])
                 else:
                     dlc = 0
 
-                dataBin = None
+                data_bin = None
             else:
-                isRemoteFrame = False
+                is_remote_frame = False
 
                 dlc = len(data) // 2
-                dataBin = bytearray()
+                data_bin = bytearray()
                 for i in range(0, len(data), 2):
-                    dataBin.append(int(data[i : (i + 2)], 16))
+                    data_bin.append(int(data[i : (i + 2)], 16))
 
-            if canId & CAN_ERR_FLAG and canId & CAN_ERR_BUSERROR:
+            if can_id & CAN_ERR_FLAG and can_id & CAN_ERR_BUSERROR:
                 msg = Message(timestamp=timestamp, is_error_frame=True)
             else:
                 msg = Message(
                     timestamp=timestamp,
-                    arbitration_id=canId & 0x1FFFFFFF,
-                    is_extended_id=isExtended,
-                    is_remote_frame=isRemoteFrame,
+                    arbitration_id=can_id & 0x1FFFFFFF,
+                    is_extended_id=is_extended,
+                    is_remote_frame=is_remote_frame,
                     is_fd=is_fd,
                     bitrate_switch=brs,
                     error_state_indicator=esi,
                     dlc=dlc,
-                    data=dataBin,
+                    data=data_bin,
                     channel=channel,
                 )
             yield msg
 
         self.stop()
 
 
-class CanutilsLogWriter(FileIOMessageWriter, Listener):
+class CanutilsLogWriter(FileIOMessageWriter):
     """Logs CAN data to an ASCII log file (.log).
     This class is is compatible with "candump -L".
 
@@ -115,7 +122,10 @@ class CanutilsLogWriter(FileIOMessageWriter, Listener):
     """
 
     def __init__(
-        self, file: AcceptedIOType, channel: str = "vcan0", append: bool = False
+        self,
+        file: Union[StringPathLike, TextIO],
+        channel: str = "vcan0",
+        append: bool = False,
     ):
         """
         :param file: a path-like object or as file-like object to write to

can/io/csv.py

@@ -10,15 +10,14 @@
 """
 
 from base64 import b64encode, b64decode
-from typing import TextIO
+from typing import TextIO, Generator, Union
 
 from can.message import Message
-from can.listener import Listener
-from .generic import BaseIOHandler, FileIOMessageWriter
-from ..typechecking import AcceptedIOType
+from .generic import FileIOMessageWriter, MessageReader
+from ..typechecking import StringPathLike
 
 
-class CSVReader(BaseIOHandler):
+class CSVReader(MessageReader):
     """Iterator over CAN messages from a .csv file that was
     generated by :class:`~can.CSVWriter` or that uses the same
     format as described there. Assumes that there is a header
@@ -27,15 +26,17 @@ class CSVReader(BaseIOHandler):
     Any line separator is accepted.
     """
 
-    def __init__(self, file: AcceptedIOType) -> None:
+    file: TextIO
+
+    def __init__(self, file: Union[StringPathLike, TextIO]) -> None:
         """
         :param file: a path-like object or as file-like object to read from
                      If this is a file-like object, is has to opened in text
                      read mode, not binary read mode.
         """
         super().__init__(file, mode="r")
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[Message, None, None]:
         # skip the header line
         try:
             next(self.file)
@@ -62,7 +63,7 @@ def __iter__(self):
         self.stop()
 
 
-class CSVWriter(FileIOMessageWriter, Listener):
+class CSVWriter(FileIOMessageWriter):
     """Writes a comma separated text file with a line for
     each message. Includes a header line.
 
@@ -85,7 +86,9 @@ class CSVWriter(FileIOMessageWriter, Listener):
 
     file: TextIO
 
-    def __init__(self, file: AcceptedIOType, append: bool = False) -> None:
+    def __init__(
+        self, file: Union[StringPathLike, TextIO], append: bool = False
+    ) -> None:
         """
         :param file: a path-like object or a file-like object to write to.
                      If this is a file-like object, is has to open in text

can/io/generic.py

@@ -5,9 +5,6 @@
     Optional,
     cast,
     Iterable,
-    Union,
-    TextIO,
-    BinaryIO,
     Type,
     ContextManager,
 )
@@ -76,21 +73,23 @@ def stop(self) -> None:
 class MessageWriter(BaseIOHandler, can.Listener, metaclass=ABCMeta):
     """The base class for all writers."""
 
+    file: Optional[can.typechecking.FileLike]
+
 
 # pylint: disable=abstract-method,too-few-public-methods
 class FileIOMessageWriter(MessageWriter, metaclass=ABCMeta):
     """A specialized base class for all writers with file descriptors."""
 
-    file: Union[TextIO, BinaryIO]
+    file: can.typechecking.FileLike
 
     def __init__(self, file: can.typechecking.AcceptedIOType, mode: str = "rt") -> None:
-        # Not possible with the type signature, but be verbose for user friendliness
+        # Not possible with the type signature, but be verbose for user-friendliness
         if file is None:
             raise ValueError("The given file cannot be None")
 
         super().__init__(file, mode)
 
 
 # pylint: disable=too-few-public-methods
-class MessageReader(BaseIOHandler, Iterable, metaclass=ABCMeta):
+class MessageReader(BaseIOHandler, Iterable[can.Message], metaclass=ABCMeta):
     """The base class for all readers."""