mirror of
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593 lines
18 KiB
Python
593 lines
18 KiB
Python
"""Common IO api utilities"""
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import bz2
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from collections import abc
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import gzip
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from io import BufferedIOBase, BytesIO, RawIOBase
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import mmap
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import os
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import pathlib
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from typing import (
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IO,
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TYPE_CHECKING,
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Any,
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AnyStr,
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Dict,
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List,
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Mapping,
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Optional,
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Tuple,
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Type,
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Union,
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)
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from urllib.parse import (
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urljoin,
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urlparse as parse_url,
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uses_netloc,
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uses_params,
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uses_relative,
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)
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import zipfile
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from pandas._typing import FilePathOrBuffer
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from pandas.compat import _get_lzma_file, _import_lzma
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from pandas.compat._optional import import_optional_dependency
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from pandas.core.dtypes.common import is_file_like
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lzma = _import_lzma()
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_VALID_URLS = set(uses_relative + uses_netloc + uses_params)
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_VALID_URLS.discard("")
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if TYPE_CHECKING:
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from io import IOBase # noqa: F401
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def is_url(url) -> bool:
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"""
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Check to see if a URL has a valid protocol.
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Parameters
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----------
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url : str or unicode
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Returns
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-------
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isurl : bool
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If `url` has a valid protocol return True otherwise False.
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"""
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if not isinstance(url, str):
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return False
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return parse_url(url).scheme in _VALID_URLS
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def _expand_user(
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filepath_or_buffer: FilePathOrBuffer[AnyStr],
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) -> FilePathOrBuffer[AnyStr]:
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"""
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Return the argument with an initial component of ~ or ~user
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replaced by that user's home directory.
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Parameters
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----------
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filepath_or_buffer : object to be converted if possible
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Returns
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-------
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expanded_filepath_or_buffer : an expanded filepath or the
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input if not expandable
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"""
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if isinstance(filepath_or_buffer, str):
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return os.path.expanduser(filepath_or_buffer)
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return filepath_or_buffer
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def validate_header_arg(header) -> None:
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if isinstance(header, bool):
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raise TypeError(
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"Passing a bool to header is invalid. Use header=None for no header or "
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"header=int or list-like of ints to specify "
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"the row(s) making up the column names"
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)
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def stringify_path(
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filepath_or_buffer: FilePathOrBuffer[AnyStr],
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) -> FilePathOrBuffer[AnyStr]:
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"""
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Attempt to convert a path-like object to a string.
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Parameters
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----------
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filepath_or_buffer : object to be converted
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Returns
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-------
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str_filepath_or_buffer : maybe a string version of the object
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Notes
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-----
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Objects supporting the fspath protocol (python 3.6+) are coerced
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according to its __fspath__ method.
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For backwards compatibility with older pythons, pathlib.Path and
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py.path objects are specially coerced.
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Any other object is passed through unchanged, which includes bytes,
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strings, buffers, or anything else that's not even path-like.
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"""
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if hasattr(filepath_or_buffer, "__fspath__"):
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# https://github.com/python/mypy/issues/1424
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return filepath_or_buffer.__fspath__() # type: ignore
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elif isinstance(filepath_or_buffer, pathlib.Path):
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return str(filepath_or_buffer)
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return _expand_user(filepath_or_buffer)
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def urlopen(*args, **kwargs):
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"""
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Lazy-import wrapper for stdlib urlopen, as that imports a big chunk of
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the stdlib.
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"""
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import urllib.request
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return urllib.request.urlopen(*args, **kwargs)
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def is_fsspec_url(url: FilePathOrBuffer) -> bool:
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"""
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Returns true if the given URL looks like
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something fsspec can handle
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"""
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return (
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isinstance(url, str)
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and "://" in url
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and not url.startswith(("http://", "https://"))
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)
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def get_filepath_or_buffer(
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filepath_or_buffer: FilePathOrBuffer,
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encoding: Optional[str] = None,
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compression: Optional[str] = None,
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mode: Optional[str] = None,
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storage_options: Optional[Dict[str, Any]] = None,
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):
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"""
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If the filepath_or_buffer is a url, translate and return the buffer.
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Otherwise passthrough.
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Parameters
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----------
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filepath_or_buffer : a url, filepath (str, py.path.local or pathlib.Path),
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or buffer
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compression : {{'gzip', 'bz2', 'zip', 'xz', None}}, optional
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encoding : the encoding to use to decode bytes, default is 'utf-8'
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mode : str, optional
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storage_options: dict, optional
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passed on to fsspec, if using it; this is not yet accessed by the public API
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Returns
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-------
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Tuple[FilePathOrBuffer, str, str, bool]
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Tuple containing the filepath or buffer, the encoding, the compression
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and should_close.
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"""
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filepath_or_buffer = stringify_path(filepath_or_buffer)
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if isinstance(filepath_or_buffer, str) and is_url(filepath_or_buffer):
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# TODO: fsspec can also handle HTTP via requests, but leaving this unchanged
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req = urlopen(filepath_or_buffer)
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content_encoding = req.headers.get("Content-Encoding", None)
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if content_encoding == "gzip":
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# Override compression based on Content-Encoding header
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compression = "gzip"
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reader = BytesIO(req.read())
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req.close()
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return reader, encoding, compression, True
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if is_fsspec_url(filepath_or_buffer):
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assert isinstance(
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filepath_or_buffer, str
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) # just to appease mypy for this branch
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# two special-case s3-like protocols; these have special meaning in Hadoop,
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# but are equivalent to just "s3" from fsspec's point of view
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# cc #11071
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if filepath_or_buffer.startswith("s3a://"):
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filepath_or_buffer = filepath_or_buffer.replace("s3a://", "s3://")
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if filepath_or_buffer.startswith("s3n://"):
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filepath_or_buffer = filepath_or_buffer.replace("s3n://", "s3://")
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fsspec = import_optional_dependency("fsspec")
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# If botocore is installed we fallback to reading with anon=True
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# to allow reads from public buckets
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err_types_to_retry_with_anon: List[Any] = []
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try:
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import_optional_dependency("botocore")
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from botocore.exceptions import ClientError, NoCredentialsError
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err_types_to_retry_with_anon = [
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ClientError,
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NoCredentialsError,
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PermissionError,
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]
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except ImportError:
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pass
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try:
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file_obj = fsspec.open(
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filepath_or_buffer, mode=mode or "rb", **(storage_options or {})
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).open()
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# GH 34626 Reads from Public Buckets without Credentials needs anon=True
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except tuple(err_types_to_retry_with_anon):
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if storage_options is None:
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storage_options = {"anon": True}
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else:
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# don't mutate user input.
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storage_options = dict(storage_options)
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storage_options["anon"] = True
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file_obj = fsspec.open(
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filepath_or_buffer, mode=mode or "rb", **(storage_options or {})
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).open()
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return file_obj, encoding, compression, True
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if isinstance(filepath_or_buffer, (str, bytes, mmap.mmap)):
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return _expand_user(filepath_or_buffer), None, compression, False
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if not is_file_like(filepath_or_buffer):
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msg = f"Invalid file path or buffer object type: {type(filepath_or_buffer)}"
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raise ValueError(msg)
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return filepath_or_buffer, None, compression, False
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def file_path_to_url(path: str) -> str:
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"""
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converts an absolute native path to a FILE URL.
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Parameters
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----------
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path : a path in native format
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Returns
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-------
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a valid FILE URL
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"""
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# lazify expensive import (~30ms)
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from urllib.request import pathname2url
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return urljoin("file:", pathname2url(path))
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_compression_to_extension = {"gzip": ".gz", "bz2": ".bz2", "zip": ".zip", "xz": ".xz"}
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def get_compression_method(
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compression: Optional[Union[str, Mapping[str, str]]]
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) -> Tuple[Optional[str], Dict[str, str]]:
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"""
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Simplifies a compression argument to a compression method string and
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a mapping containing additional arguments.
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Parameters
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----------
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compression : str or mapping
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If string, specifies the compression method. If mapping, value at key
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'method' specifies compression method.
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Returns
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-------
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tuple of ({compression method}, Optional[str]
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{compression arguments}, Dict[str, str])
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Raises
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------
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ValueError on mapping missing 'method' key
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"""
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if isinstance(compression, Mapping):
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compression_args = dict(compression)
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try:
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compression = compression_args.pop("method")
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except KeyError as err:
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raise ValueError("If mapping, compression must have key 'method'") from err
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else:
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compression_args = {}
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return compression, compression_args
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def infer_compression(
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filepath_or_buffer: FilePathOrBuffer, compression: Optional[str]
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) -> Optional[str]:
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"""
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Get the compression method for filepath_or_buffer. If compression='infer',
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the inferred compression method is returned. Otherwise, the input
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compression method is returned unchanged, unless it's invalid, in which
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case an error is raised.
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Parameters
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----------
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filepath_or_buffer : str or file handle
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File path or object.
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compression : {'infer', 'gzip', 'bz2', 'zip', 'xz', None}
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If 'infer' and `filepath_or_buffer` is path-like, then detect
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compression from the following extensions: '.gz', '.bz2', '.zip',
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or '.xz' (otherwise no compression).
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Returns
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-------
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string or None
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Raises
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------
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ValueError on invalid compression specified.
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"""
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# No compression has been explicitly specified
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if compression is None:
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return None
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# Infer compression
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if compression == "infer":
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# Convert all path types (e.g. pathlib.Path) to strings
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filepath_or_buffer = stringify_path(filepath_or_buffer)
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if not isinstance(filepath_or_buffer, str):
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# Cannot infer compression of a buffer, assume no compression
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return None
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# Infer compression from the filename/URL extension
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for compression, extension in _compression_to_extension.items():
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if filepath_or_buffer.lower().endswith(extension):
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return compression
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return None
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# Compression has been specified. Check that it's valid
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if compression in _compression_to_extension:
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return compression
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msg = f"Unrecognized compression type: {compression}"
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valid = ["infer", None] + sorted(_compression_to_extension)
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msg += f"\nValid compression types are {valid}"
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raise ValueError(msg)
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def get_handle(
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path_or_buf,
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mode: str,
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encoding=None,
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compression: Optional[Union[str, Mapping[str, Any]]] = None,
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memory_map: bool = False,
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is_text: bool = True,
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errors=None,
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):
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"""
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Get file handle for given path/buffer and mode.
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Parameters
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----------
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path_or_buf : str or file handle
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File path or object.
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mode : str
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Mode to open path_or_buf with.
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encoding : str or None
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Encoding to use.
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compression : str or dict, default None
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If string, specifies compression mode. If dict, value at key 'method'
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specifies compression mode. Compression mode must be one of {'infer',
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'gzip', 'bz2', 'zip', 'xz', None}. If compression mode is 'infer'
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and `filepath_or_buffer` is path-like, then detect compression from
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the following extensions: '.gz', '.bz2', '.zip', or '.xz' (otherwise
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no compression). If dict and compression mode is one of
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{'zip', 'gzip', 'bz2'}, or inferred as one of the above,
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other entries passed as additional compression options.
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.. versionchanged:: 1.0.0
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May now be a dict with key 'method' as compression mode
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and other keys as compression options if compression
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mode is 'zip'.
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.. versionchanged:: 1.1.0
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Passing compression options as keys in dict is now
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supported for compression modes 'gzip' and 'bz2' as well as 'zip'.
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memory_map : boolean, default False
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See parsers._parser_params for more information.
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is_text : boolean, default True
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whether file/buffer is in text format (csv, json, etc.), or in binary
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mode (pickle, etc.).
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errors : str, default 'strict'
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Specifies how encoding and decoding errors are to be handled.
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See the errors argument for :func:`open` for a full list
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of options.
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.. versionadded:: 1.1.0
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Returns
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-------
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f : file-like
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A file-like object.
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handles : list of file-like objects
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A list of file-like object that were opened in this function.
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"""
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need_text_wrapping: Tuple[Type["IOBase"], ...]
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try:
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from s3fs import S3File
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need_text_wrapping = (BufferedIOBase, RawIOBase, S3File)
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except ImportError:
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need_text_wrapping = (BufferedIOBase, RawIOBase)
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handles: List[IO] = list()
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f = path_or_buf
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# Convert pathlib.Path/py.path.local or string
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path_or_buf = stringify_path(path_or_buf)
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is_path = isinstance(path_or_buf, str)
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compression, compression_args = get_compression_method(compression)
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if is_path:
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compression = infer_compression(path_or_buf, compression)
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if compression:
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# GH33398 the type ignores here seem related to mypy issue #5382;
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# it may be possible to remove them once that is resolved.
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# GZ Compression
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if compression == "gzip":
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if is_path:
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f = gzip.open(
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path_or_buf, mode, **compression_args # type: ignore
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)
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else:
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f = gzip.GzipFile(
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fileobj=path_or_buf, **compression_args # type: ignore
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)
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# BZ Compression
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elif compression == "bz2":
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if is_path:
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f = bz2.BZ2File(
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path_or_buf, mode, **compression_args # type: ignore
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)
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else:
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f = bz2.BZ2File(path_or_buf, **compression_args) # type: ignore
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# ZIP Compression
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elif compression == "zip":
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zf = _BytesZipFile(path_or_buf, mode, **compression_args)
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# Ensure the container is closed as well.
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handles.append(zf)
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if zf.mode == "w":
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f = zf
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elif zf.mode == "r":
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zip_names = zf.namelist()
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if len(zip_names) == 1:
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f = zf.open(zip_names.pop())
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elif len(zip_names) == 0:
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raise ValueError(f"Zero files found in ZIP file {path_or_buf}")
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else:
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raise ValueError(
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"Multiple files found in ZIP file. "
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f"Only one file per ZIP: {zip_names}"
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)
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# XZ Compression
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elif compression == "xz":
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f = _get_lzma_file(lzma)(path_or_buf, mode)
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# Unrecognized Compression
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else:
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msg = f"Unrecognized compression type: {compression}"
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raise ValueError(msg)
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handles.append(f)
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elif is_path:
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if encoding:
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# Encoding
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f = open(path_or_buf, mode, encoding=encoding, errors=errors, newline="")
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elif is_text:
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# No explicit encoding
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f = open(path_or_buf, mode, errors="replace", newline="")
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else:
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# Binary mode
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f = open(path_or_buf, mode)
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handles.append(f)
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# Convert BytesIO or file objects passed with an encoding
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if is_text and (compression or isinstance(f, need_text_wrapping)):
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from io import TextIOWrapper
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g = TextIOWrapper(f, encoding=encoding, errors=errors, newline="")
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if not isinstance(f, (BufferedIOBase, RawIOBase)):
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handles.append(g)
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f = g
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if memory_map and hasattr(f, "fileno"):
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try:
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wrapped = _MMapWrapper(f)
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f.close()
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f = wrapped
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except Exception:
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# we catch any errors that may have occurred
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# because that is consistent with the lower-level
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# functionality of the C engine (pd.read_csv), so
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# leave the file handler as is then
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pass
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return f, handles
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class _BytesZipFile(zipfile.ZipFile, BytesIO): # type: ignore
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"""
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Wrapper for standard library class ZipFile and allow the returned file-like
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handle to accept byte strings via `write` method.
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BytesIO provides attributes of file-like object and ZipFile.writestr writes
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bytes strings into a member of the archive.
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"""
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# GH 17778
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def __init__(
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self,
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file: FilePathOrBuffer,
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mode: str,
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archive_name: Optional[str] = None,
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**kwargs,
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):
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if mode in ["wb", "rb"]:
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mode = mode.replace("b", "")
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self.archive_name = archive_name
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super().__init__(file, mode, zipfile.ZIP_DEFLATED, **kwargs)
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def write(self, data):
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|
archive_name = self.filename
|
|
if self.archive_name is not None:
|
|
archive_name = self.archive_name
|
|
super().writestr(archive_name, data)
|
|
|
|
@property
|
|
def closed(self):
|
|
return self.fp is None
|
|
|
|
|
|
class _MMapWrapper(abc.Iterator):
|
|
"""
|
|
Wrapper for the Python's mmap class so that it can be properly read in
|
|
by Python's csv.reader class.
|
|
|
|
Parameters
|
|
----------
|
|
f : file object
|
|
File object to be mapped onto memory. Must support the 'fileno'
|
|
method or have an equivalent attribute
|
|
|
|
"""
|
|
|
|
def __init__(self, f: IO):
|
|
self.mmap = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
|
|
|
|
def __getattr__(self, name: str):
|
|
return getattr(self.mmap, name)
|
|
|
|
def __iter__(self) -> "_MMapWrapper":
|
|
return self
|
|
|
|
def __next__(self) -> str:
|
|
newbytes = self.mmap.readline()
|
|
|
|
# readline returns bytes, not str, but Python's CSV reader
|
|
# expects str, so convert the output to str before continuing
|
|
newline = newbytes.decode("utf-8")
|
|
|
|
# mmap doesn't raise if reading past the allocated
|
|
# data but instead returns an empty string, so raise
|
|
# if that is returned
|
|
if newline == "":
|
|
raise StopIteration
|
|
return newline
|