Current File : //lib/python3/dist-packages/dns/_features.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
import importlib.metadata
import itertools
import string
from typing import Dict, List, Tuple
def _tuple_from_text(version: str) -> Tuple:
text_parts = version.split(".")
int_parts = []
for text_part in text_parts:
digit_prefix = "".join(
itertools.takewhile(lambda x: x in string.digits, text_part)
)
try:
int_parts.append(int(digit_prefix))
except Exception:
break
return tuple(int_parts)
def _version_check(
requirement: str,
) -> bool:
"""Is the requirement fulfilled?
The requirement must be of the form
package>=version
"""
package, minimum = requirement.split(">=")
try:
version = importlib.metadata.version(package)
except Exception:
return False
t_version = _tuple_from_text(version)
t_minimum = _tuple_from_text(minimum)
if t_version < t_minimum:
return False
return True
_cache: Dict[str, bool] = {}
def have(feature: str) -> bool:
"""Is *feature* available?
This tests if all optional packages needed for the
feature are available and recent enough.
Returns ``True`` if the feature is available,
and ``False`` if it is not or if metadata is
missing.
"""
value = _cache.get(feature)
if value is not None:
return value
requirements = _requirements.get(feature)
if requirements is None:
# we make a cache entry here for consistency not performance
_cache[feature] = False
return False
ok = True
for requirement in requirements:
if not _version_check(requirement):
ok = False
break
_cache[feature] = ok
return ok
def force(feature: str, enabled: bool) -> None:
"""Force the status of *feature* to be *enabled*.
This method is provided as a workaround for any cases
where importlib.metadata is ineffective, or for testing.
"""
_cache[feature] = enabled
_requirements: Dict[str, List[str]] = {
### BEGIN generated requirements
"dnssec": ["cryptography>=41"],
"doh": ["httpcore>=1.0.0", "httpx>=0.26.0", "h2>=4.1.0"],
"doq": ["aioquic>=0.9.25"],
"idna": ["idna>=3.6"],
"trio": ["trio>=0.23"],
"wmi": ["wmi>=1.5.1"],
### END generated requirements
}
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