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# Source code for can.thread_safe_bus

    from threading import RLock

    try:
        # Only raise an exception on instantiation but allow module
        # to be imported
        from wrapt import ObjectProxy

        import_exc = None
    except ImportError as exc:
        ObjectProxy = object
        import_exc = exc

    from contextlib import nullcontext

    from .interface import Bus

    class ThreadSafeBus(ObjectProxy):  # pylint: disable=abstract-method
        """
        Contains a thread safe :class:`can.BusABC` implementation that
        wraps around an existing interface instance. All public methods
        of that base class are now safe to be called from multiple threads.
        The send and receive methods are synchronized separately.

        Use this as a drop-in replacement for :class:`~can.BusABC`.

        .. note::

            This approach assumes that both :meth:`~can.BusABC.send` and
            :meth:`~can.BusABC._recv_internal` of the underlying bus instance can be
            called simultaneously, and that the methods use :meth:`~can.BusABC._recv_internal`
            instead of :meth:`~can.BusABC.recv` directly.
        """

        def __init__(self, *args, **kwargs):
            if import_exc is not None:
                raise import_exc

            super().__init__(Bus(*args, **kwargs))

            # now, BusABC.send_periodic() does not need a lock anymore, but the
            # implementation still requires a context manager
            self.__wrapped__._lock_send_periodic = nullcontext()

            # init locks for sending and receiving separately
            self._lock_send = RLock()
            self._lock_recv = RLock()

        def recv(
            self, timeout=None, *args, **kwargs
        ):  # pylint: disable=keyword-arg-before-vararg
            with self._lock_recv:
                return self.__wrapped__.recv(timeout=timeout, *args, **kwargs)

        def send(
            self, msg, timeout=None, *args, **kwargs
        ):  # pylint: disable=keyword-arg-before-vararg
            with self._lock_send:
                return self.__wrapped__.send(msg, timeout=timeout, *args, **kwargs)

        # send_periodic does not need a lock, since the underlying
        # `send` method is already synchronized

        @property
        def filters(self):
            with self._lock_recv:
                return self.__wrapped__.filters

        @filters.setter
        def filters(self, filters):
            with self._lock_recv:
                self.__wrapped__.filters = filters

        def set_filters(
            self, filters=None, *args, **kwargs
        ):  # pylint: disable=keyword-arg-before-vararg
            with self._lock_recv:
                return self.__wrapped__.set_filters(filters=filters, *args, **kwargs)

        def flush_tx_buffer(self, *args, **kwargs):
            with self._lock_send:
                return self.__wrapped__.flush_tx_buffer(*args, **kwargs)

        def shutdown(self, *args, **kwargs):
            with self._lock_send, self._lock_recv:
                return self.__wrapped__.shutdown(*args, **kwargs)

        @property
        def state(self):
            with self._lock_send, self._lock_recv:
                return self.__wrapped__.state

        @state.setter
        def state(self, new_state):
            with self._lock_send, self._lock_recv:
                self.__wrapped__.state = new_state