diff options
Diffstat (limited to 'venv/lib/python3.11/site-packages/websockets/imports.py')
-rw-r--r-- | venv/lib/python3.11/site-packages/websockets/imports.py | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/websockets/imports.py b/venv/lib/python3.11/site-packages/websockets/imports.py new file mode 100644 index 0000000..a6a59d4 --- /dev/null +++ b/venv/lib/python3.11/site-packages/websockets/imports.py @@ -0,0 +1,99 @@ +from __future__ import annotations + +import warnings +from typing import Any, Dict, Iterable, Optional + + +__all__ = ["lazy_import"] + + +def import_name(name: str, source: str, namespace: Dict[str, Any]) -> Any: + """ + Import ``name`` from ``source`` in ``namespace``. + + There are two use cases: + + - ``name`` is an object defined in ``source``; + - ``name`` is a submodule of ``source``. + + Neither :func:`__import__` nor :func:`~importlib.import_module` does + exactly this. :func:`__import__` is closer to the intended behavior. + + """ + level = 0 + while source[level] == ".": + level += 1 + assert level < len(source), "importing from parent isn't supported" + module = __import__(source[level:], namespace, None, [name], level) + return getattr(module, name) + + +def lazy_import( + namespace: Dict[str, Any], + aliases: Optional[Dict[str, str]] = None, + deprecated_aliases: Optional[Dict[str, str]] = None, +) -> None: + """ + Provide lazy, module-level imports. + + Typical use:: + + __getattr__, __dir__ = lazy_import( + globals(), + aliases={ + "<name>": "<source module>", + ... + }, + deprecated_aliases={ + ..., + } + ) + + This function defines ``__getattr__`` and ``__dir__`` per :pep:`562`. + + """ + if aliases is None: + aliases = {} + if deprecated_aliases is None: + deprecated_aliases = {} + + namespace_set = set(namespace) + aliases_set = set(aliases) + deprecated_aliases_set = set(deprecated_aliases) + + assert not namespace_set & aliases_set, "namespace conflict" + assert not namespace_set & deprecated_aliases_set, "namespace conflict" + assert not aliases_set & deprecated_aliases_set, "namespace conflict" + + package = namespace["__name__"] + + def __getattr__(name: str) -> Any: + assert aliases is not None # mypy cannot figure this out + try: + source = aliases[name] + except KeyError: + pass + else: + return import_name(name, source, namespace) + + assert deprecated_aliases is not None # mypy cannot figure this out + try: + source = deprecated_aliases[name] + except KeyError: + pass + else: + warnings.warn( + f"{package}.{name} is deprecated", + DeprecationWarning, + stacklevel=2, + ) + return import_name(name, source, namespace) + + raise AttributeError(f"module {package!r} has no attribute {name!r}") + + namespace["__getattr__"] = __getattr__ + + def __dir__() -> Iterable[str]: + return sorted(namespace_set | aliases_set | deprecated_aliases_set) + + namespace["__dir__"] = __dir__ |