Module aws_lambda_powertools.shared.types

def TypedDict(typename, fields=None, /, *, total=True, **kwargs):
    """A simple typed namespace. At runtime it is equivalent to a plain dict.

    TypedDict creates a dictionary type such that a type checker will expect all
    instances to have a certain set of keys, where each key is
    associated with a value of a consistent type. This expectation
    is not checked at runtime.

    Usage::

        class Point2D(TypedDict):
            x: int
            y: int
            label: str

        a: Point2D = {'x': 1, 'y': 2, 'label': 'good'}  # OK
        b: Point2D = {'z': 3, 'label': 'bad'}           # Fails type check

        assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')

    The type info can be accessed via the Point2D.__annotations__ dict, and
    the Point2D.__required_keys__ and Point2D.__optional_keys__ frozensets.
    TypedDict supports an additional equivalent form::

        Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})

    By default, all keys must be present in a TypedDict. It is possible
    to override this by specifying totality::

        class Point2D(TypedDict, total=False):
            x: int
            y: int

    This means that a Point2D TypedDict can have any of the keys omitted. A type
    checker is only expected to support a literal False or True as the value of
    the total argument. True is the default, and makes all items defined in the
    class body be required.

    The Required and NotRequired special forms can also be used to mark
    individual keys as being required or not required::

        class Point2D(TypedDict):
            x: int               # the "x" key must always be present (Required is the default)
            y: NotRequired[int]  # the "y" key can be omitted

    See PEP 655 for more details on Required and NotRequired.
    """
    if fields is None:
        fields = kwargs
    elif kwargs:
        raise TypeError("TypedDict takes either a dict or keyword arguments,"
                        " but not both")
    if kwargs:
        warnings.warn(
            "The kwargs-based syntax for TypedDict definitions is deprecated "
            "in Python 3.11, will be removed in Python 3.13, and may not be "
            "understood by third-party type checkers.",
            DeprecationWarning,
            stacklevel=2,
        )

    ns = {'__annotations__': dict(fields)}
    module = _caller()
    if module is not None:
        # Setting correct module is necessary to make typed dict classes pickleable.
        ns['__module__'] = module

    return _TypedDictMeta(typename, (), ns, total=total)

def get_args(tp):
    """Get type arguments with all substitutions performed.

    For unions, basic simplifications used by Union constructor are performed.

    Examples::

        assert get_args(Dict[str, int]) == (str, int)
        assert get_args(int) == ()
        assert get_args(Union[int, Union[T, int], str][int]) == (int, str)
        assert get_args(Union[int, Tuple[T, int]][str]) == (int, Tuple[str, int])
        assert get_args(Callable[[], T][int]) == ([], int)
    """
    if isinstance(tp, _AnnotatedAlias):
        return (tp.__origin__,) + tp.__metadata__
    if isinstance(tp, (_GenericAlias, GenericAlias)):
        res = tp.__args__
        if _should_unflatten_callable_args(tp, res):
            res = (list(res[:-1]), res[-1])
        return res
    if isinstance(tp, types.UnionType):
        return tp.__args__
    return ()

def get_origin(tp):
    """Get the unsubscripted version of a type.

    This supports generic types, Callable, Tuple, Union, Literal, Final, ClassVar,
    Annotated, and others. Return None for unsupported types.

    Examples::

        assert get_origin(Literal[42]) is Literal
        assert get_origin(int) is None
        assert get_origin(ClassVar[int]) is ClassVar
        assert get_origin(Generic) is Generic
        assert get_origin(Generic[T]) is Generic
        assert get_origin(Union[T, int]) is Union
        assert get_origin(List[Tuple[T, T]][int]) is list
        assert get_origin(P.args) is P
    """
    if isinstance(tp, _AnnotatedAlias):
        return Annotated
    if isinstance(tp, (_BaseGenericAlias, GenericAlias,
                       ParamSpecArgs, ParamSpecKwargs)):
        return tp.__origin__
    if tp is Generic:
        return Generic
    if isinstance(tp, types.UnionType):
        return types.UnionType
    return None

class Annotated:
    """Add context-specific metadata to a type.

    Example: Annotated[int, runtime_check.Unsigned] indicates to the
    hypothetical runtime_check module that this type is an unsigned int.
    Every other consumer of this type can ignore this metadata and treat
    this type as int.

    The first argument to Annotated must be a valid type.

    Details:

    - It's an error to call `Annotated` with less than two arguments.
    - Access the metadata via the ``__metadata__`` attribute::

        assert Annotated[int, '$'].__metadata__ == ('$',)

    - Nested Annotated types are flattened::

        assert Annotated[Annotated[T, Ann1, Ann2], Ann3] == Annotated[T, Ann1, Ann2, Ann3]

    - Instantiating an annotated type is equivalent to instantiating the
    underlying type::

        assert Annotated[C, Ann1](5) == C(5)

    - Annotated can be used as a generic type alias::

        Optimized: TypeAlias = Annotated[T, runtime.Optimize()]
        assert Optimized[int] == Annotated[int, runtime.Optimize()]

        OptimizedList: TypeAlias = Annotated[list[T], runtime.Optimize()]
        assert OptimizedList[int] == Annotated[list[int], runtime.Optimize()]

    - Annotated cannot be used with an unpacked TypeVarTuple::

        Variadic: TypeAlias = Annotated[*Ts, Ann1]  # NOT valid

      This would be equivalent to::

        Annotated[T1, T2, T3, ..., Ann1]

      where T1, T2 etc. are TypeVars, which would be invalid, because
      only one type should be passed to Annotated.
    """

    __slots__ = ()

    def __new__(cls, *args, **kwargs):
        raise TypeError("Type Annotated cannot be instantiated.")

    @_tp_cache
    def __class_getitem__(cls, params):
        if not isinstance(params, tuple) or len(params) < 2:
            raise TypeError("Annotated[...] should be used "
                            "with at least two arguments (a type and an "
                            "annotation).")
        if _is_unpacked_typevartuple(params[0]):
            raise TypeError("Annotated[...] should not be used with an "
                            "unpacked TypeVarTuple")
        msg = "Annotated[t, ...]: t must be a type."
        origin = _type_check(params[0], msg, allow_special_forms=True)
        metadata = tuple(params[1:])
        return _AnnotatedAlias(origin, metadata)

    def __init_subclass__(cls, *args, **kwargs):
        raise TypeError(
            "Cannot subclass {}.Annotated".format(cls.__module__)
        )

class Protocol(Generic, metaclass=_ProtocolMeta):
    """Base class for protocol classes.

    Protocol classes are defined as::

        class Proto(Protocol):
            def meth(self) -> int:
                ...

    Such classes are primarily used with static type checkers that recognize
    structural subtyping (static duck-typing).

    For example::

        class C:
            def meth(self) -> int:
                return 0

        def func(x: Proto) -> int:
            return x.meth()

        func(C())  # Passes static type check

    See PEP 544 for details. Protocol classes decorated with
    @typing.runtime_checkable act as simple-minded runtime protocols that check
    only the presence of given attributes, ignoring their type signatures.
    Protocol classes can be generic, they are defined as::

        class GenProto(Protocol[T]):
            def meth(self) -> T:
                ...
    """

    __slots__ = ()
    _is_protocol = True
    _is_runtime_protocol = False

    def __init_subclass__(cls, *args, **kwargs):
        super().__init_subclass__(*args, **kwargs)

        # Determine if this is a protocol or a concrete subclass.
        if not cls.__dict__.get('_is_protocol', False):
            cls._is_protocol = any(b is Protocol for b in cls.__bases__)

        # Set (or override) the protocol subclass hook.
        def _proto_hook(other):
            if not cls.__dict__.get('_is_protocol', False):
                return NotImplemented

            # First, perform various sanity checks.
            if not getattr(cls, '_is_runtime_protocol', False):
                if _allow_reckless_class_checks():
                    return NotImplemented
                raise TypeError("Instance and class checks can only be used with"
                                " @runtime_checkable protocols")
            if not _is_callable_members_only(cls):
                if _allow_reckless_class_checks():
                    return NotImplemented
                raise TypeError("Protocols with non-method members"
                                " don't support issubclass()")
            if not isinstance(other, type):
                # Same error message as for issubclass(1, int).
                raise TypeError('issubclass() arg 1 must be a class')

            # Second, perform the actual structural compatibility check.
            for attr in _get_protocol_attrs(cls):
                for base in other.__mro__:
                    # Check if the members appears in the class dictionary...
                    if attr in base.__dict__:
                        if base.__dict__[attr] is None:
                            return NotImplemented
                        break

                    # ...or in annotations, if it is a sub-protocol.
                    annotations = getattr(base, '__annotations__', {})
                    if (isinstance(annotations, collections.abc.Mapping) and
                            attr in annotations and
                            issubclass(other, Generic) and other._is_protocol):
                        break
                else:
                    return NotImplemented
            return True

        if '__subclasshook__' not in cls.__dict__:
            cls.__subclasshook__ = _proto_hook

        # We have nothing more to do for non-protocols...
        if not cls._is_protocol:
            return

        # ... otherwise check consistency of bases, and prohibit instantiation.
        for base in cls.__bases__:
            if not (base in (object, Generic) or
                    base.__module__ in _PROTO_ALLOWLIST and
                    base.__name__ in _PROTO_ALLOWLIST[base.__module__] or
                    issubclass(base, Generic) and base._is_protocol):
                raise TypeError('Protocols can only inherit from other'
                                ' protocols, got %r' % base)
        if cls.__init__ is Protocol.__init__:
            cls.__init__ = _no_init_or_replace_init