forked from varia/varia.website
149 lines
4.3 KiB
Python
149 lines
4.3 KiB
Python
from __future__ import annotations
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from collections.abc import Callable, Mapping
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from io import SEEK_SET, UnsupportedOperation
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from os import PathLike
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from pathlib import Path
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from typing import Any, BinaryIO, cast
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from .. import (
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BrokenResourceError,
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ClosedResourceError,
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EndOfStream,
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TypedAttributeSet,
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to_thread,
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typed_attribute,
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)
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from ..abc import ByteReceiveStream, ByteSendStream
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class FileStreamAttribute(TypedAttributeSet):
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#: the open file descriptor
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file: BinaryIO = typed_attribute()
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#: the path of the file on the file system, if available (file must be a real file)
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path: Path = typed_attribute()
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#: the file number, if available (file must be a real file or a TTY)
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fileno: int = typed_attribute()
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class _BaseFileStream:
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def __init__(self, file: BinaryIO):
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self._file = file
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async def aclose(self) -> None:
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await to_thread.run_sync(self._file.close)
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@property
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def extra_attributes(self) -> Mapping[Any, Callable[[], Any]]:
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attributes: dict[Any, Callable[[], Any]] = {
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FileStreamAttribute.file: lambda: self._file,
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}
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if hasattr(self._file, "name"):
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attributes[FileStreamAttribute.path] = lambda: Path(self._file.name)
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try:
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self._file.fileno()
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except UnsupportedOperation:
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pass
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else:
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attributes[FileStreamAttribute.fileno] = lambda: self._file.fileno()
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return attributes
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class FileReadStream(_BaseFileStream, ByteReceiveStream):
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"""
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A byte stream that reads from a file in the file system.
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:param file: a file that has been opened for reading in binary mode
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.. versionadded:: 3.0
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"""
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@classmethod
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async def from_path(cls, path: str | PathLike[str]) -> FileReadStream:
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"""
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Create a file read stream by opening the given file.
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:param path: path of the file to read from
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"""
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file = await to_thread.run_sync(Path(path).open, "rb")
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return cls(cast(BinaryIO, file))
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async def receive(self, max_bytes: int = 65536) -> bytes:
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try:
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data = await to_thread.run_sync(self._file.read, max_bytes)
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except ValueError:
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raise ClosedResourceError from None
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except OSError as exc:
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raise BrokenResourceError from exc
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if data:
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return data
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else:
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raise EndOfStream
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async def seek(self, position: int, whence: int = SEEK_SET) -> int:
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"""
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Seek the file to the given position.
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.. seealso:: :meth:`io.IOBase.seek`
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.. note:: Not all file descriptors are seekable.
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:param position: position to seek the file to
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:param whence: controls how ``position`` is interpreted
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:return: the new absolute position
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:raises OSError: if the file is not seekable
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"""
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return await to_thread.run_sync(self._file.seek, position, whence)
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async def tell(self) -> int:
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"""
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Return the current stream position.
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.. note:: Not all file descriptors are seekable.
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:return: the current absolute position
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:raises OSError: if the file is not seekable
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"""
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return await to_thread.run_sync(self._file.tell)
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class FileWriteStream(_BaseFileStream, ByteSendStream):
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"""
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A byte stream that writes to a file in the file system.
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:param file: a file that has been opened for writing in binary mode
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.. versionadded:: 3.0
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"""
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@classmethod
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async def from_path(
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cls, path: str | PathLike[str], append: bool = False
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) -> FileWriteStream:
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"""
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Create a file write stream by opening the given file for writing.
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:param path: path of the file to write to
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:param append: if ``True``, open the file for appending; if ``False``, any
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existing file at the given path will be truncated
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"""
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mode = "ab" if append else "wb"
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file = await to_thread.run_sync(Path(path).open, mode)
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return cls(cast(BinaryIO, file))
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async def send(self, item: bytes) -> None:
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try:
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await to_thread.run_sync(self._file.write, item)
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except ValueError:
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raise ClosedResourceError from None
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except OSError as exc:
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raise BrokenResourceError from exc
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