96 lines
2.8 KiB
Python
96 lines
2.8 KiB
Python
import asyncio
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from typing import Optional, cast
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from .helpers import set_exception
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from .tcp_helpers import tcp_nodelay
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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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"_drain_waiter",
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"_connection_lost",
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"_reading_paused",
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"transport",
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)
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def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
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self._loop: asyncio.AbstractEventLoop = loop
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self._paused = False
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self._drain_waiter: Optional[asyncio.Future[None]] = None
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self._reading_paused = False
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self.transport: Optional[asyncio.Transport] = 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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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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if not self._reading_paused and self.transport is not None:
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try:
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self.transport.pause_reading()
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except (AttributeError, NotImplementedError, RuntimeError):
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pass
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self._reading_paused = True
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def resume_reading(self) -> None:
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if self._reading_paused and self.transport is not None:
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try:
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self.transport.resume_reading()
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except (AttributeError, NotImplementedError, RuntimeError):
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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: Optional[BaseException]) -> 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 not self.connected:
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raise ConnectionResetError("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 asyncio.shield(waiter)
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