Method initialize

tornado/platform/asyncio.py:95–142

(  # type: ignore
        self, asyncio_loop: asyncio.AbstractEventLoop, **kwargs: Any
    )

class BaseAsyncIOLoop(IOLoop):
    def initialize(  # type: ignore
        self, asyncio_loop: asyncio.AbstractEventLoop, **kwargs: Any
    ) -> None:
        # asyncio_loop is always the real underlying IOLoop. This is used in
        # ioloop.py to maintain the asyncio-to-ioloop mappings.
        self.asyncio_loop = asyncio_loop
        # selector_loop is an event loop that implements the add_reader family of
        # methods. Usually the same as asyncio_loop but differs on platforms such
        # as windows where the default event loop does not implement these methods.
        self.selector_loop = asyncio_loop
        if hasattr(asyncio, "ProactorEventLoop") and isinstance(
            asyncio_loop, asyncio.ProactorEventLoop
        ):
            # Ignore this line for mypy because the abstract method checker
            # doesn't understand dynamic proxies.
            self.selector_loop = AddThreadSelectorEventLoop(asyncio_loop)  # type: ignore
        # Maps fd to (fileobj, handler function) pair (as in IOLoop.add_handler)
        self.handlers: Dict[int, Tuple[Union[int, _Selectable], Callable]] = {}
        # Set of fds listening for reads/writes
        self.readers: Set[int] = set()
        self.writers: Set[int] = set()
        self.closing = False
        # If an asyncio loop was closed through an asyncio interface
        # instead of IOLoop.close(), we'd never hear about it and may
        # have left a dangling reference in our map. In case an
        # application (or, more likely, a test suite) creates and
        # destroys a lot of event loops in this way, check here to
        # ensure that we don't have a lot of dead loops building up in
        # the map.
        #
        # TODO(bdarnell): consider making self.asyncio_loop a weakref
        # for AsyncIOMainLoop and make _ioloop_for_asyncio a
        # WeakKeyDictionary.
        for loop in IOLoop._ioloop_for_asyncio.copy():
            if loop.is_closed():
                try:
                    del IOLoop._ioloop_for_asyncio[loop]
                except KeyError:
                    pass

        # Make sure we don't already have an IOLoop for this asyncio loop
        existing_loop = IOLoop._ioloop_for_asyncio.setdefault(asyncio_loop, self)
        if existing_loop is not self:
            raise RuntimeError(
                f"IOLoop {existing_loop} already associated with asyncio loop {asyncio_loop}"
            )

        super().initialize(**kwargs)

    def close(self, all_fds: bool = False) -> None:
        self.closing = True