projektAI/venv/Lib/site-packages/pandas/_config/localization.py
2021-06-06 22:13:05 +02:00

167 lines
4.9 KiB
Python

"""
Helpers for configuring locale settings.
Name `localization` is chosen to avoid overlap with builtin `locale` module.
"""
from contextlib import contextmanager
import locale
import re
import subprocess
from pandas._config.config import options
@contextmanager
def set_locale(new_locale, lc_var: int = locale.LC_ALL):
"""
Context manager for temporarily setting a locale.
Parameters
----------
new_locale : str or tuple
A string of the form <language_country>.<encoding>. For example to set
the current locale to US English with a UTF8 encoding, you would pass
"en_US.UTF-8".
lc_var : int, default `locale.LC_ALL`
The category of the locale being set.
Notes
-----
This is useful when you want to run a particular block of code under a
particular locale, without globally setting the locale. This probably isn't
thread-safe.
"""
current_locale = locale.getlocale()
try:
locale.setlocale(lc_var, new_locale)
normalized_locale = locale.getlocale()
if all(x is not None for x in normalized_locale):
yield ".".join(normalized_locale)
else:
yield new_locale
finally:
locale.setlocale(lc_var, current_locale)
def can_set_locale(lc: str, lc_var: int = locale.LC_ALL) -> bool:
"""
Check to see if we can set a locale, and subsequently get the locale,
without raising an Exception.
Parameters
----------
lc : str
The locale to attempt to set.
lc_var : int, default `locale.LC_ALL`
The category of the locale being set.
Returns
-------
bool
Whether the passed locale can be set
"""
try:
with set_locale(lc, lc_var=lc_var):
pass
except (ValueError, locale.Error):
# horrible name for a Exception subclass
return False
else:
return True
def _valid_locales(locales, normalize):
"""
Return a list of normalized locales that do not throw an ``Exception``
when set.
Parameters
----------
locales : str
A string where each locale is separated by a newline.
normalize : bool
Whether to call ``locale.normalize`` on each locale.
Returns
-------
valid_locales : list
A list of valid locales.
"""
return [
loc
for loc in (
locale.normalize(loc.strip()) if normalize else loc.strip()
for loc in locales
)
if can_set_locale(loc)
]
def _default_locale_getter():
return subprocess.check_output(["locale -a"], shell=True)
def get_locales(prefix=None, normalize=True, locale_getter=_default_locale_getter):
"""
Get all the locales that are available on the system.
Parameters
----------
prefix : str
If not ``None`` then return only those locales with the prefix
provided. For example to get all English language locales (those that
start with ``"en"``), pass ``prefix="en"``.
normalize : bool
Call ``locale.normalize`` on the resulting list of available locales.
If ``True``, only locales that can be set without throwing an
``Exception`` are returned.
locale_getter : callable
The function to use to retrieve the current locales. This should return
a string with each locale separated by a newline character.
Returns
-------
locales : list of strings
A list of locale strings that can be set with ``locale.setlocale()``.
For example::
locale.setlocale(locale.LC_ALL, locale_string)
On error will return None (no locale available, e.g. Windows)
"""
try:
raw_locales = locale_getter()
except subprocess.CalledProcessError:
# Raised on (some? all?) Windows platforms because Note: "locale -a"
# is not defined
return None
try:
# raw_locales is "\n" separated list of locales
# it may contain non-decodable parts, so split
# extract what we can and then rejoin.
raw_locales = raw_locales.split(b"\n")
out_locales = []
for x in raw_locales:
try:
out_locales.append(str(x, encoding=options.display.encoding))
except UnicodeError:
# 'locale -a' is used to populated 'raw_locales' and on
# Redhat 7 Linux (and maybe others) prints locale names
# using windows-1252 encoding. Bug only triggered by
# a few special characters and when there is an
# extensive list of installed locales.
out_locales.append(str(x, encoding="windows-1252"))
except TypeError:
pass
if prefix is None:
return _valid_locales(out_locales, normalize)
pattern = re.compile(f"{prefix}.*")
found = pattern.findall("\n".join(out_locales))
return _valid_locales(found, normalize)