| |
|
|
| 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: |
| |
| _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]] = { |
| |
| "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"], |
| |
| } |
|
|
