# coding: utf-8
Contains a generic class for file IO.
from abc import ABCMeta
from typing import Optional, cast
"""A generic file handler that can be used for reading and writing.
Can be used as a context manager.
:attr Optional[FileLike] file:
the file-like object that is kept internally, or None if none
def __init__(self, file: can.typechecking.AcceptedIOType, mode: str = "rt") -> None:
:param file: a path-like object to open a file, a file-like object
to be used as a file or `None` to not use a file at all
:param mode: the mode that should be used to open the file, see
:func:`open`, ignored if *file* is `None`
if file is None or (hasattr(file, "read") and hasattr(file, "write")):
# file is None or some file-like object
self.file = cast(Optional[can.typechecking.FileLike], file)
# file is some path-like object
self.file = open(cast(can.typechecking.StringPathLike, file), mode)
# for multiple inheritance
def __enter__(self) -> "BaseIOHandler":
def __exit__(self, *args) -> None:
# pylint: disable=abstract-method,too-few-public-methods
[docs] def stop(self) -> None:
"""Closes the undelying file-like object and flushes it, if it was opened in write mode."""
if self.file is not None:
# this also implies a flush()
self.file.close() [docs]class MessageWriter(BaseIOHandler, can.Listener, metaclass=ABCMeta):
"""The base class for all writers."""
# pylint: disable=too-few-public-methods
[docs]class MessageReader(BaseIOHandler, metaclass=ABCMeta):
"""The base class for all readers."""