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# Source code for can.io.logger

    """
    See the :class:`Logger` class.
    """

    import gzip
    import os
    import pathlib
    from abc import ABC, abstractmethod
    from datetime import datetime
    from types import TracebackType
    from typing import Any, Callable, Dict, Literal, Optional, Set, Tuple, Type, cast

    from typing_extensions import Self

    from .._entry_points import read_entry_points
    from ..listener import Listener
    from ..message import Message
    from ..typechecking import AcceptedIOType, FileLike, StringPathLike
    from .asc import ASCWriter
    from .blf import BLFWriter
    from .canutils import CanutilsLogWriter
    from .csv import CSVWriter
    from .generic import (
        BaseIOHandler,
        BinaryIOMessageWriter,
        FileIOMessageWriter,
        MessageWriter,
    )
    from .mf4 import MF4Writer
    from .printer import Printer
    from .sqlite import SqliteWriter
    from .trc import TRCWriter

    class Logger(MessageWriter):
        """
        Logs CAN messages to a file.

        The format is determined from the file suffix which can be one of:
          * .asc: :class:`can.ASCWriter`
          * .blf :class:`can.BLFWriter`
          * .csv: :class:`can.CSVWriter`
          * .db: :class:`can.SqliteWriter`
          * .log :class:`can.CanutilsLogWriter`
          * .trc :class:`can.TRCWriter`
          * .txt :class:`can.Printer`
          * .mf4 :class:`can.MF4Writer` (optional, depends on asammdf)

        Any of these formats can be used with gzip compression by appending
        the suffix .gz (e.g. filename.asc.gz). However, third-party tools might not
        be able to read these files.

        The **filename** may also be *None*, to fall back to :class:`can.Printer`.

        The log files may be incomplete until `stop()` is called due to buffering.

        .. note::
            This class itself is just a dispatcher, and any positional and keyword
            arguments are passed on to the returned instance.
        """

        fetched_plugins = False
        message_writers: Dict[str, Type[MessageWriter]] = {
            ".asc": ASCWriter,
            ".blf": BLFWriter,
            ".csv": CSVWriter,
            ".db": SqliteWriter,
            ".log": CanutilsLogWriter,
            ".mf4": MF4Writer,
            ".trc": TRCWriter,
            ".txt": Printer,
        }

        @staticmethod
        def __new__(  # type: ignore
            cls: Any, filename: Optional[StringPathLike], **kwargs: Any
        ) -> MessageWriter:
            """
            :param filename:
                the filename/path of the file to write to,
                may be a path-like object or None to
                instantiate a :class:`~can.Printer`
            :raises ValueError:
                if the filename's suffix is of an unknown file type
            """
            if filename is None:
                return Printer(**kwargs)

            if not Logger.fetched_plugins:
                Logger.message_writers.update(
                    {
                        writer.key: cast(Type[MessageWriter], writer.load())
                        for writer in read_entry_points("can.io.message_writer")
                    }
                )
                Logger.fetched_plugins = True

            suffix = pathlib.PurePath(filename).suffix.lower()

            file_or_filename: AcceptedIOType = filename
            if suffix == ".gz":
                logger_type, file_or_filename = Logger.compress(filename, **kwargs)
            else:
                logger_type = cls._get_logger_for_suffix(suffix)

            return logger_type(file=file_or_filename, **kwargs)

        @classmethod
        def _get_logger_for_suffix(cls, suffix: str) -> Type[MessageWriter]:
            try:
                logger_type = Logger.message_writers[suffix]
                if logger_type is None:
                    raise ValueError(f'failed to import logger for extension "{suffix}"')
                return logger_type
            except KeyError:
                raise ValueError(
                    f'No write support for this unknown log format "{suffix}"'
                ) from None

        @classmethod
        def compress(
            cls, filename: StringPathLike, **kwargs: Any
        ) -> Tuple[Type[MessageWriter], FileLike]:
            """
            Return the suffix and io object of the decompressed file.
            File will automatically recompress upon close.
            """
            real_suffix = pathlib.Path(filename).suffixes[-2].lower()
            if real_suffix in (".blf", ".db"):
                raise ValueError(
                    f"The file type {real_suffix} is currently incompatible with gzip."
                )
            logger_type = cls._get_logger_for_suffix(real_suffix)
            append = kwargs.get("append", False)

            if issubclass(logger_type, BinaryIOMessageWriter):
                mode = "ab" if append else "wb"
            else:
                mode = "at" if append else "wt"

            return logger_type, gzip.open(filename, mode)

        def on_message_received(self, msg: Message) -> None:
            pass

    class BaseRotatingLogger(Listener, BaseIOHandler, ABC):
        """
        Base class for rotating CAN loggers. This class is not meant to be
        instantiated directly. Subclasses must implement the :meth:`should_rollover`
        and :meth:`do_rollover` methods according to their rotation strategy.

        The rotation behavior can be further customized by the user by setting
        the :attr:`namer` and :attr:`rotator` attributes after instantiating the subclass.

        These attributes as well as the methods :meth:`rotation_filename` and :meth:`rotate`
        and the corresponding docstrings are carried over from the python builtin
        :class:`~logging.handlers.BaseRotatingHandler`.

        Subclasses must set the `_writer` attribute upon initialization.
        """

        _supported_formats: Set[str] = set()

        #: If this attribute is set to a callable, the :meth:`~BaseRotatingLogger.rotation_filename`
        #: method delegates to this callable. The parameters passed to the callable are
        #: those passed to :meth:`~BaseRotatingLogger.rotation_filename`.
        namer: Optional[Callable[[StringPathLike], StringPathLike]] = None

        #: If this attribute is set to a callable, the :meth:`~BaseRotatingLogger.rotate` method
        #: delegates to this callable. The parameters passed to the callable are those
        #: passed to :meth:`~BaseRotatingLogger.rotate`.
        rotator: Optional[Callable[[StringPathLike, StringPathLike], None]] = None

        #: An integer counter to track the number of rollovers.
        rollover_count: int = 0

        def __init__(self, **kwargs: Any) -> None:
            Listener.__init__(self)
            BaseIOHandler.__init__(self, file=None)

            self.writer_kwargs = kwargs

            # Expected to be set by the subclass
            self._writer: FileIOMessageWriter = None  # type: ignore

        @property
        def writer(self) -> FileIOMessageWriter:
            """This attribute holds an instance of a writer class which manages the actual file IO."""
            return self._writer

        def rotation_filename(self, default_name: StringPathLike) -> StringPathLike:
            """Modify the filename of a log file when rotating.

            This is provided so that a custom filename can be provided.
            The default implementation calls the :attr:`namer` attribute of the
            handler, if it's callable, passing the default name to
            it. If the attribute isn't callable (the default is :obj:`None`), the name
            is returned unchanged.

            :param default_name:
                The default name for the log file.
            """
            if not callable(self.namer):
                return default_name

            return self.namer(default_name)  # pylint: disable=not-callable

        def rotate(self, source: StringPathLike, dest: StringPathLike) -> None:
            """When rotating, rotate the current log.

            The default implementation calls the :attr:`rotator` attribute of the
            handler, if it's callable, passing the `source` and `dest` arguments to
            it. If the attribute isn't callable (the default is :obj:`None`), the source
            is simply renamed to the destination.

            :param source:
                The source filename. This is normally the base
                filename, e.g. `"test.log"`
            :param dest:
                The destination filename. This is normally
                what the source is rotated to, e.g. `"test_#001.log"`.
            """
            if not callable(self.rotator):
                if os.path.exists(source):
                    os.rename(source, dest)
            else:
                self.rotator(source, dest)  # pylint: disable=not-callable

        def on_message_received(self, msg: Message) -> None:
            """This method is called to handle the given message.

            :param msg:
                the delivered message
            """
            if self.should_rollover(msg):
                self.do_rollover()
                self.rollover_count += 1

            self.writer.on_message_received(msg)

        def _get_new_writer(self, filename: StringPathLike) -> FileIOMessageWriter:
            """Instantiate a new writer.

            .. note::
                The :attr:`self.writer` should be closed prior to calling this function.

            :param filename:
                Path-like object that specifies the location and name of the log file.
                The log file format is defined by the suffix of `filename`.
            :return:
                An instance of a writer class.
            """
            suffix = "".join(pathlib.Path(filename).suffixes[-2:]).lower()

            if suffix in self._supported_formats:
                logger = Logger(filename=filename, **self.writer_kwargs)
                if isinstance(logger, FileIOMessageWriter):
                    return logger
                elif isinstance(logger, Printer) and logger.file is not None:
                    return cast(FileIOMessageWriter, logger)

            raise ValueError(
                f'The log format "{suffix}" '
                f"is not supported by {self.__class__.__name__}. "
                f"{self.__class__.__name__} supports the following formats: "
                f"{', '.join(self._supported_formats)}"
            )

        def stop(self) -> None:
            """Stop handling new messages.

            Carry out any final tasks to ensure
            data is persisted and cleanup any open resources.
            """
            self.writer.stop()

        def __enter__(self) -> Self:
            return self

        def __exit__(
            self,
            exc_type: Optional[Type[BaseException]],
            exc_val: Optional[BaseException],
            exc_tb: Optional[TracebackType],
        ) -> Literal[False]:
            return self._writer.__exit__(exc_type, exc_val, exc_tb)

        @abstractmethod
        def should_rollover(self, msg: Message) -> bool:
            """Determine if the rollover conditions are met."""

        @abstractmethod
        def do_rollover(self) -> None:
            """Perform rollover."""

    class SizedRotatingLogger(BaseRotatingLogger):
        """Log CAN messages to a sequence of files with a given maximum size.

        The logger creates a log file with the given `base_filename`. When the
        size threshold is reached the current log file is closed and renamed
        by adding a timestamp and the rollover count. A new log file is then
        created and written to.

        This behavior can be customized by setting the
        :attr:`~can.io.BaseRotatingLogger.namer` and
        :attr:`~can.io.BaseRotatingLogger.rotator`
        attribute.

        Example::

            from can import Notifier, SizedRotatingLogger
            from can.interfaces.vector import VectorBus

            bus = VectorBus(channel=[0], app_name="CANape", fd=True)

            logger = SizedRotatingLogger(
                base_filename="my_logfile.asc",
                max_bytes=5 * 1024 ** 2,  # =5MB
            )
            logger.rollover_count = 23  # start counter at 23

            notifier = Notifier(bus=bus, listeners=[logger])

        The SizedRotatingLogger currently supports the formats
          * .asc: :class:`can.ASCWriter`
          * .blf :class:`can.BLFWriter`
          * .csv: :class:`can.CSVWriter`
          * .log :class:`can.CanutilsLogWriter`
          * .txt :class:`can.Printer` (if pointing to a file)

        .. note::
            The :class:`can.SqliteWriter` is not supported yet.

        The log files on disk may be incomplete due to buffering until
        :meth:`~can.Listener.stop` is called.
        """

        _supported_formats = {".asc", ".blf", ".csv", ".log", ".txt"}

        def __init__(
            self,
            base_filename: StringPathLike,
            max_bytes: int = 0,
            **kwargs: Any,
        ) -> None:
            """
            :param base_filename:
                A path-like object for the base filename. The log file format is defined by
                the suffix of `base_filename`.
            :param max_bytes:
                The size threshold at which a new log file shall be created. If set to 0, no
                rollover will be performed.
            """
            super().__init__(**kwargs)

            self.base_filename = os.path.abspath(base_filename)
            self.max_bytes = max_bytes

            self._writer = self._get_new_writer(self.base_filename)

        def should_rollover(self, msg: Message) -> bool:
            if self.max_bytes <= 0:
                return False

            if self.writer.file_size() >= self.max_bytes:
                return True

            return False

        def do_rollover(self) -> None:
            if self.writer:
                self.writer.stop()

            sfn = self.base_filename
            dfn = self.rotation_filename(self._default_name())
            self.rotate(sfn, dfn)

            self._writer = self._get_new_writer(self.base_filename)

        def _default_name(self) -> StringPathLike:
            """Generate the default rotation filename."""
            path = pathlib.Path(self.base_filename)
            new_name = (
                path.stem.split(".")[0]
                + "_"
                + datetime.now().strftime("%Y-%m-%dT%H%M%S")
                + "_"
                + f"#{self.rollover_count:03}"
                + "".join(path.suffixes[-2:])
            )
            return str(path.parent / new_name)