diff options
Diffstat (limited to 'venv/lib/python3.11/site-packages/anyio/streams/buffered.py')
-rw-r--r-- | venv/lib/python3.11/site-packages/anyio/streams/buffered.py | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/anyio/streams/buffered.py b/venv/lib/python3.11/site-packages/anyio/streams/buffered.py new file mode 100644 index 0000000..f5d5e83 --- /dev/null +++ b/venv/lib/python3.11/site-packages/anyio/streams/buffered.py @@ -0,0 +1,119 @@ +from __future__ import annotations + +from collections.abc import Callable, Mapping +from dataclasses import dataclass, field +from typing import Any + +from .. import ClosedResourceError, DelimiterNotFound, EndOfStream, IncompleteRead +from ..abc import AnyByteReceiveStream, ByteReceiveStream + + +@dataclass(eq=False) +class BufferedByteReceiveStream(ByteReceiveStream): + """ + Wraps any bytes-based receive stream and uses a buffer to provide sophisticated + receiving capabilities in the form of a byte stream. + """ + + receive_stream: AnyByteReceiveStream + _buffer: bytearray = field(init=False, default_factory=bytearray) + _closed: bool = field(init=False, default=False) + + async def aclose(self) -> None: + await self.receive_stream.aclose() + self._closed = True + + @property + def buffer(self) -> bytes: + """The bytes currently in the buffer.""" + return bytes(self._buffer) + + @property + def extra_attributes(self) -> Mapping[Any, Callable[[], Any]]: + return self.receive_stream.extra_attributes + + async def receive(self, max_bytes: int = 65536) -> bytes: + if self._closed: + raise ClosedResourceError + + if self._buffer: + chunk = bytes(self._buffer[:max_bytes]) + del self._buffer[:max_bytes] + return chunk + elif isinstance(self.receive_stream, ByteReceiveStream): + return await self.receive_stream.receive(max_bytes) + else: + # With a bytes-oriented object stream, we need to handle any surplus bytes + # we get from the receive() call + chunk = await self.receive_stream.receive() + if len(chunk) > max_bytes: + # Save the surplus bytes in the buffer + self._buffer.extend(chunk[max_bytes:]) + return chunk[:max_bytes] + else: + return chunk + + async def receive_exactly(self, nbytes: int) -> bytes: + """ + Read exactly the given amount of bytes from the stream. + + :param nbytes: the number of bytes to read + :return: the bytes read + :raises ~anyio.IncompleteRead: if the stream was closed before the requested + amount of bytes could be read from the stream + + """ + while True: + remaining = nbytes - len(self._buffer) + if remaining <= 0: + retval = self._buffer[:nbytes] + del self._buffer[:nbytes] + return bytes(retval) + + try: + if isinstance(self.receive_stream, ByteReceiveStream): + chunk = await self.receive_stream.receive(remaining) + else: + chunk = await self.receive_stream.receive() + except EndOfStream as exc: + raise IncompleteRead from exc + + self._buffer.extend(chunk) + + async def receive_until(self, delimiter: bytes, max_bytes: int) -> bytes: + """ + Read from the stream until the delimiter is found or max_bytes have been read. + + :param delimiter: the marker to look for in the stream + :param max_bytes: maximum number of bytes that will be read before raising + :exc:`~anyio.DelimiterNotFound` + :return: the bytes read (not including the delimiter) + :raises ~anyio.IncompleteRead: if the stream was closed before the delimiter + was found + :raises ~anyio.DelimiterNotFound: if the delimiter is not found within the + bytes read up to the maximum allowed + + """ + delimiter_size = len(delimiter) + offset = 0 + while True: + # Check if the delimiter can be found in the current buffer + index = self._buffer.find(delimiter, offset) + if index >= 0: + found = self._buffer[:index] + del self._buffer[: index + len(delimiter) :] + return bytes(found) + + # Check if the buffer is already at or over the limit + if len(self._buffer) >= max_bytes: + raise DelimiterNotFound(max_bytes) + + # Read more data into the buffer from the socket + try: + data = await self.receive_stream.receive() + except EndOfStream as exc: + raise IncompleteRead from exc + + # Move the offset forward and add the new data to the buffer + offset = max(len(self._buffer) - delimiter_size + 1, 0) + self._buffer.extend(data) |