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mofixx
364
Code/venv/lib/python3.13/site-packages/aioquic/quic/stream.py
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364
Code/venv/lib/python3.13/site-packages/aioquic/quic/stream.py
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from typing import Optional
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from . import events
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from .packet import (
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QuicErrorCode,
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QuicResetStreamFrame,
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QuicStopSendingFrame,
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QuicStreamFrame,
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)
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from .packet_builder import QuicDeliveryState
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from .rangeset import RangeSet
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class FinalSizeError(Exception):
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pass
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class StreamFinishedError(Exception):
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pass
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class QuicStreamReceiver:
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"""
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The receive part of a QUIC stream.
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It finishes:
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- immediately for a send-only stream
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- upon reception of a STREAM_RESET frame
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- upon reception of a data frame with the FIN bit set
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"""
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def __init__(self, stream_id: Optional[int], readable: bool) -> None:
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self.highest_offset = 0 # the highest offset ever seen
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self.is_finished = False
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self.stop_pending = False
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self._buffer = bytearray()
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self._buffer_start = 0 # the offset for the start of the buffer
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self._final_size: Optional[int] = None
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self._ranges = RangeSet()
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self._stream_id = stream_id
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self._stop_error_code: Optional[int] = None
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def get_stop_frame(self) -> QuicStopSendingFrame:
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self.stop_pending = False
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return QuicStopSendingFrame(
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error_code=self._stop_error_code,
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stream_id=self._stream_id,
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)
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def starting_offset(self) -> int:
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return self._buffer_start
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def handle_frame(
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self, frame: QuicStreamFrame
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) -> Optional[events.StreamDataReceived]:
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"""
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Handle a frame of received data.
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"""
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pos = frame.offset - self._buffer_start
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count = len(frame.data)
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frame_end = frame.offset + count
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# we should receive no more data beyond FIN!
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if self._final_size is not None:
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if frame_end > self._final_size:
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raise FinalSizeError("Data received beyond final size")
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elif frame.fin and frame_end != self._final_size:
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raise FinalSizeError("Cannot change final size")
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if frame.fin:
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self._final_size = frame_end
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if frame_end > self.highest_offset:
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self.highest_offset = frame_end
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# fast path: new in-order chunk
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if pos == 0 and count and not self._buffer:
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self._buffer_start += count
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if frame.fin:
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# all data up to the FIN has been received, we're done receiving
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self.is_finished = True
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return events.StreamDataReceived(
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data=frame.data, end_stream=frame.fin, stream_id=self._stream_id
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)
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# discard duplicate data
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if pos < 0:
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frame.data = frame.data[-pos:]
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frame.offset -= pos
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pos = 0
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count = len(frame.data)
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# marked received range
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if frame_end > frame.offset:
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self._ranges.add(frame.offset, frame_end)
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# add new data
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gap = pos - len(self._buffer)
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if gap > 0:
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self._buffer += bytearray(gap)
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self._buffer[pos : pos + count] = frame.data
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# return data from the front of the buffer
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data = self._pull_data()
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end_stream = self._buffer_start == self._final_size
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if end_stream:
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# all data up to the FIN has been received, we're done receiving
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self.is_finished = True
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if data or end_stream:
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return events.StreamDataReceived(
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data=data, end_stream=end_stream, stream_id=self._stream_id
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)
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else:
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return None
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def handle_reset(
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self, *, final_size: int, error_code: int = QuicErrorCode.NO_ERROR
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) -> Optional[events.StreamReset]:
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"""
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Handle an abrupt termination of the receiving part of the QUIC stream.
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"""
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if self._final_size is not None and final_size != self._final_size:
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raise FinalSizeError("Cannot change final size")
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# we are done receiving
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self._final_size = final_size
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self.is_finished = True
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return events.StreamReset(error_code=error_code, stream_id=self._stream_id)
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def on_stop_sending_delivery(self, delivery: QuicDeliveryState) -> None:
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"""
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Callback when a STOP_SENDING is ACK'd.
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"""
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if delivery != QuicDeliveryState.ACKED:
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self.stop_pending = True
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def stop(self, error_code: int = QuicErrorCode.NO_ERROR) -> None:
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"""
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Request the peer stop sending data on the QUIC stream.
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"""
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self._stop_error_code = error_code
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self.stop_pending = True
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def _pull_data(self) -> bytes:
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"""
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Remove data from the front of the buffer.
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"""
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try:
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has_data_to_read = self._ranges[0].start == self._buffer_start
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except IndexError:
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has_data_to_read = False
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if not has_data_to_read:
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return b""
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r = self._ranges.shift()
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pos = r.stop - r.start
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data = bytes(self._buffer[:pos])
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del self._buffer[:pos]
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self._buffer_start = r.stop
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return data
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class QuicStreamSender:
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"""
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The send part of a QUIC stream.
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It finishes:
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- immediately for a receive-only stream
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- upon acknowledgement of a STREAM_RESET frame
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- upon acknowledgement of a data frame with the FIN bit set
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"""
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def __init__(self, stream_id: Optional[int], writable: bool) -> None:
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self.buffer_is_empty = True
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self.highest_offset = 0
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self.is_finished = not writable
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self.reset_pending = False
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self._acked = RangeSet()
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self._acked_fin = False
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self._buffer = bytearray()
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self._buffer_fin: Optional[int] = None
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self._buffer_start = 0 # the offset for the start of the buffer
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self._buffer_stop = 0 # the offset for the stop of the buffer
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self._pending = RangeSet()
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self._pending_eof = False
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self._reset_error_code: Optional[int] = None
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self._stream_id = stream_id
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@property
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def next_offset(self) -> int:
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"""
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The offset for the next frame to send.
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This is used to determine the space needed for the frame's `offset` field.
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"""
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try:
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return self._pending[0].start
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except IndexError:
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return self._buffer_stop
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def get_frame(
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self, max_size: int, max_offset: Optional[int] = None
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) -> Optional[QuicStreamFrame]:
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"""
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Get a frame of data to send.
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"""
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assert self._reset_error_code is None, "cannot call get_frame() after reset()"
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# get the first pending data range
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try:
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r = self._pending[0]
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except IndexError:
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if self._pending_eof:
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# FIN only
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self._pending_eof = False
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return QuicStreamFrame(fin=True, offset=self._buffer_fin)
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self.buffer_is_empty = True
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return None
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# apply flow control
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start = r.start
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stop = min(r.stop, start + max_size)
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if max_offset is not None and stop > max_offset:
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stop = max_offset
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if stop <= start:
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return None
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# create frame
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frame = QuicStreamFrame(
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data=bytes(
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self._buffer[start - self._buffer_start : stop - self._buffer_start]
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),
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offset=start,
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)
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self._pending.subtract(start, stop)
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# track the highest offset ever sent
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if stop > self.highest_offset:
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self.highest_offset = stop
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# if the buffer is empty and EOF was written, set the FIN bit
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if self._buffer_fin == stop:
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frame.fin = True
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self._pending_eof = False
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return frame
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def get_reset_frame(self) -> QuicResetStreamFrame:
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self.reset_pending = False
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return QuicResetStreamFrame(
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error_code=self._reset_error_code,
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final_size=self.highest_offset,
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stream_id=self._stream_id,
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)
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def on_data_delivery(
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self, delivery: QuicDeliveryState, start: int, stop: int, fin: bool
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) -> None:
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"""
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Callback when sent data is ACK'd.
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"""
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# If the frame had the FIN bit set, its end MUST match otherwise
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# we have a programming error.
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assert (
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not fin or stop == self._buffer_fin
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), "on_data_delivered() was called with inconsistent fin / stop"
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# If a reset has been requested, stop processing data delivery.
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# The transition to the finished state only depends on the reset
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# being acknowledged.
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if self._reset_error_code is not None:
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return
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if delivery == QuicDeliveryState.ACKED:
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if stop > start:
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# Some data has been ACK'd, discard it.
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self._acked.add(start, stop)
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first_range = self._acked[0]
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if first_range.start == self._buffer_start:
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size = first_range.stop - first_range.start
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self._acked.shift()
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self._buffer_start += size
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del self._buffer[:size]
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if fin:
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# The FIN has been ACK'd.
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self._acked_fin = True
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if self._buffer_start == self._buffer_fin and self._acked_fin:
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# All data and the FIN have been ACK'd, we're done sending.
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self.is_finished = True
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else:
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if stop > start:
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# Some data has been lost, reschedule it.
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self.buffer_is_empty = False
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self._pending.add(start, stop)
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if fin:
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# The FIN has been lost, reschedule it.
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self.buffer_is_empty = False
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self._pending_eof = True
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def on_reset_delivery(self, delivery: QuicDeliveryState) -> None:
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"""
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Callback when a reset is ACK'd.
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"""
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if delivery == QuicDeliveryState.ACKED:
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# The reset has been ACK'd, we're done sending.
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self.is_finished = True
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else:
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# The reset has been lost, reschedule it.
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self.reset_pending = True
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def reset(self, error_code: int) -> None:
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"""
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Abruptly terminate the sending part of the QUIC stream.
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"""
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assert self._reset_error_code is None, "cannot call reset() more than once"
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self._reset_error_code = error_code
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self.reset_pending = True
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# Prevent any more data from being sent or re-sent.
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self.buffer_is_empty = True
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def write(self, data: bytes, end_stream: bool = False) -> None:
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"""
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Write some data bytes to the QUIC stream.
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"""
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assert self._buffer_fin is None, "cannot call write() after FIN"
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assert self._reset_error_code is None, "cannot call write() after reset()"
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size = len(data)
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if size:
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self.buffer_is_empty = False
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self._pending.add(self._buffer_stop, self._buffer_stop + size)
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self._buffer += data
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self._buffer_stop += size
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if end_stream:
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self.buffer_is_empty = False
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self._buffer_fin = self._buffer_stop
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self._pending_eof = True
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class QuicStream:
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def __init__(
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self,
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stream_id: Optional[int] = None,
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max_stream_data_local: int = 0,
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max_stream_data_remote: int = 0,
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readable: bool = True,
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writable: bool = True,
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) -> None:
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self.is_blocked = False
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self.max_stream_data_local = max_stream_data_local
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self.max_stream_data_local_sent = max_stream_data_local
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self.max_stream_data_remote = max_stream_data_remote
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self.receiver = QuicStreamReceiver(stream_id=stream_id, readable=readable)
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self.sender = QuicStreamSender(stream_id=stream_id, writable=writable)
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self.stream_id = stream_id
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@property
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def is_finished(self) -> bool:
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return self.receiver.is_finished and self.sender.is_finished
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