141 lines
4.6 KiB
Python
141 lines
4.6 KiB
Python
import asyncio
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from typing import TYPE_CHECKING, Any, cast
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from .client_exceptions import ClientConnectionResetError
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from .helpers import set_exception
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from .tcp_helpers import tcp_nodelay
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if TYPE_CHECKING:
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from .http_parser import HttpParser
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# Raised by transport.pause_reading()/resume_reading() when the transport
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# does not support flow control; safe to ignore.
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# NOTE: Catch these with a plain try/except/pass, never contextlib.suppress():
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# pause/resume run on the hot read path and suppress() is ~6x slower than
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# try/except here (it builds a context manager and unpacks this tuple per call).
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PAUSE_RESUME_READING_ERRORS = (AttributeError, NotImplementedError, RuntimeError)
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class BaseProtocol(asyncio.Protocol):
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__slots__ = (
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"_loop",
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"_paused",
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"_parser",
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"_drain_waiter",
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"_connection_lost",
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"_reading_paused",
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"_upgraded",
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"transport",
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)
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def __init__(
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self, loop: asyncio.AbstractEventLoop, parser: "HttpParser[Any] | None" = None
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) -> None:
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self._loop: asyncio.AbstractEventLoop = loop
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self._paused = False
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self._drain_waiter: asyncio.Future[None] | None = None
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self._reading_paused = False
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self._parser = parser
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self._upgraded = False
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self.transport: asyncio.Transport | None = None
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@property
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def connected(self) -> bool:
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"""Return True if the connection is open."""
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return self.transport is not None
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@property
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def writing_paused(self) -> bool:
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return self._paused
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def pause_writing(self) -> None:
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assert not self._paused
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self._paused = True
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def resume_writing(self) -> None:
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assert self._paused
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self._paused = False
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waiter = self._drain_waiter
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if waiter is not None:
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self._drain_waiter = None
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if not waiter.done():
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waiter.set_result(None)
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def pause_reading(self) -> None:
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self._reading_paused = True
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# Parser shouldn't be paused on websockets.
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if not self._upgraded:
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assert self._parser is not None
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self._parser.pause_reading()
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if self.transport is not None:
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try:
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self.transport.pause_reading()
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except PAUSE_RESUME_READING_ERRORS:
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# Transport lacks flow control; nothing to pause. Intentionally
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# ignored (see PAUSE_RESUME_READING_ERRORS; do not use suppress).
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pass
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def _reading_paused_for_msg_queue(self) -> bool:
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"""Keep the transport paused for protocol-specific reasons (overridden)."""
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return False
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def resume_reading(self, resume_parser: bool = True) -> None:
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self._reading_paused = False
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# This will resume parsing any unprocessed data from the last pause.
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if not self._upgraded and resume_parser:
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self.data_received(b"")
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# Reading may have been paused again in the above call if there was a lot of
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# compressed data still pending.
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if (
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not self._reading_paused
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and not self._reading_paused_for_msg_queue()
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and self.transport is not None
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):
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try:
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self.transport.resume_reading()
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except PAUSE_RESUME_READING_ERRORS:
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# Transport lacks flow control; nothing to resume. Intentionally
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# ignored (see PAUSE_RESUME_READING_ERRORS; do not use suppress).
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pass
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self._reading_paused = False
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def connection_made(self, transport: asyncio.BaseTransport) -> None:
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tr = cast(asyncio.Transport, transport)
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tcp_nodelay(tr, True)
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self.transport = tr
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def connection_lost(self, exc: BaseException | None) -> None:
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# Wake up the writer if currently paused.
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self.transport = None
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if not self._paused:
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return
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waiter = self._drain_waiter
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if waiter is None:
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return
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self._drain_waiter = None
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if waiter.done():
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return
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if exc is None:
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waiter.set_result(None)
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else:
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set_exception(
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waiter,
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ConnectionError("Connection lost"),
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exc,
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)
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async def _drain_helper(self) -> None:
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if self.transport is None:
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raise ClientConnectionResetError("Connection lost")
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if not self._paused:
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return
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waiter = self._drain_waiter
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if waiter is None:
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waiter = self._loop.create_future()
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self._drain_waiter = waiter
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await waiter
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