abc — pymatgen 2020.7.3 documentation

# Source code for abc

    # Copyright 2007 Google, Inc. All Rights Reserved.
    # Licensed to PSF under a Contributor Agreement.

    """Abstract Base Classes (ABCs) according to PEP 3119."""

    def abstractmethod(funcobj):
        """A decorator indicating abstract methods.

        Requires that the metaclass is ABCMeta or derived from it.  A
        class that has a metaclass derived from ABCMeta cannot be
        instantiated unless all of its abstract methods are overridden.
        The abstract methods can be called using any of the normal
        'super' call mechanisms.

        Usage:

            class C(metaclass=ABCMeta):
                @abstractmethod
                def my_abstract_method(self, ...):
                    ...
        """
        funcobj.__isabstractmethod__ = True
        return funcobj

    class abstractclassmethod(classmethod):
        """A decorator indicating abstract classmethods.

        Similar to abstractmethod.

        Usage:

            class C(metaclass=ABCMeta):
                @abstractclassmethod
                def my_abstract_classmethod(cls, ...):
                    ...

        'abstractclassmethod' is deprecated. Use 'classmethod' with
        'abstractmethod' instead.
        """

        __isabstractmethod__ = True

        def __init__(self, callable):
            callable.__isabstractmethod__ = True
            super().__init__(callable)

    class abstractstaticmethod(staticmethod):
        """A decorator indicating abstract staticmethods.

        Similar to abstractmethod.

        Usage:

            class C(metaclass=ABCMeta):
                @abstractstaticmethod
                def my_abstract_staticmethod(...):
                    ...

        'abstractstaticmethod' is deprecated. Use 'staticmethod' with
        'abstractmethod' instead.
        """

        __isabstractmethod__ = True

        def __init__(self, callable):
            callable.__isabstractmethod__ = True
            super().__init__(callable)

    class abstractproperty(property):
        """A decorator indicating abstract properties.

        Requires that the metaclass is ABCMeta or derived from it.  A
        class that has a metaclass derived from ABCMeta cannot be
        instantiated unless all of its abstract properties are overridden.
        The abstract properties can be called using any of the normal
        'super' call mechanisms.

        Usage:

            class C(metaclass=ABCMeta):
                @abstractproperty
                def my_abstract_property(self):
                    ...

        This defines a read-only property; you can also define a read-write
        abstract property using the 'long' form of property declaration:

            class C(metaclass=ABCMeta):
                def getx(self): ...
                def setx(self, value): ...
                x = abstractproperty(getx, setx)

        'abstractproperty' is deprecated. Use 'property' with 'abstractmethod'
        instead.
        """

        __isabstractmethod__ = True

    try:
        from _abc import (get_cache_token, _abc_init, _abc_register,
                          _abc_instancecheck, _abc_subclasscheck, _get_dump,
                          _reset_registry, _reset_caches)
    except ImportError:
        from _py_abc import ABCMeta, get_cache_token
        ABCMeta.__module__ = 'abc'
    else:
        class ABCMeta(type):
            """Metaclass for defining Abstract Base Classes (ABCs).

            Use this metaclass to create an ABC.  An ABC can be subclassed
            directly, and then acts as a mix-in class.  You can also register
            unrelated concrete classes (even built-in classes) and unrelated
            ABCs as 'virtual subclasses' -- these and their descendants will
            be considered subclasses of the registering ABC by the built-in
            issubclass() function, but the registering ABC won't show up in
            their MRO (Method Resolution Order) nor will method
            implementations defined by the registering ABC be callable (not
            even via super()).
            """
            def __new__(mcls, name, bases, namespace, **kwargs):
                cls = super().__new__(mcls, name, bases, namespace, **kwargs)
                _abc_init(cls)
                return cls

            def register(cls, subclass):
                """Register a virtual subclass of an ABC.

                Returns the subclass, to allow usage as a class decorator.
                """
                return _abc_register(cls, subclass)

            def __instancecheck__(cls, instance):
                """Override for isinstance(instance, cls)."""
                return _abc_instancecheck(cls, instance)

            def __subclasscheck__(cls, subclass):
                """Override for issubclass(subclass, cls)."""
                return _abc_subclasscheck(cls, subclass)

            def _dump_registry(cls, file=None):
                """Debug helper to print the ABC registry."""
                print(f"Class: {cls.__module__}.{cls.__qualname__}", file=file)
                print(f"Inv. counter: {get_cache_token()}", file=file)
                (_abc_registry, _abc_cache, _abc_negative_cache,
                 _abc_negative_cache_version) = _get_dump(cls)
                print(f"_abc_registry: {_abc_registry!r}", file=file)
                print(f"_abc_cache: {_abc_cache!r}", file=file)
                print(f"_abc_negative_cache: {_abc_negative_cache!r}", file=file)
                print(f"_abc_negative_cache_version: {_abc_negative_cache_version!r}",
                      file=file)

            def _abc_registry_clear(cls):
                """Clear the registry (for debugging or testing)."""
                _reset_registry(cls)

            def _abc_caches_clear(cls):
                """Clear the caches (for debugging or testing)."""
                _reset_caches(cls)

    class ABC(metaclass=ABCMeta):
        """Helper class that provides a standard way to create an ABC using
        inheritance.
        """
        __slots__ = ()