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Diffstat (limited to 'third_party/python/attrs/attr/_funcs.py')
| -rw-r--r-- | third_party/python/attrs/attr/_funcs.py | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/third_party/python/attrs/attr/_funcs.py b/third_party/python/attrs/attr/_funcs.py new file mode 100644 index 0000000000..7f5d9610f3 --- /dev/null +++ b/third_party/python/attrs/attr/_funcs.py @@ -0,0 +1,477 @@ +# SPDX-License-Identifier: MIT + + +import copy + +from ._compat import PY_3_9_PLUS, get_generic_base +from ._make import NOTHING, _obj_setattr, fields +from .exceptions import AttrsAttributeNotFoundError + + +def asdict( + inst, + recurse=True, + filter=None, + dict_factory=dict, + retain_collection_types=False, + value_serializer=None, +): + """ + Return the *attrs* attribute values of *inst* as a dict. + + Optionally recurse into other *attrs*-decorated classes. + + :param inst: Instance of an *attrs*-decorated class. + :param bool recurse: Recurse into classes that are also + *attrs*-decorated. + :param callable filter: A callable whose return code determines whether an + attribute or element is included (``True``) or dropped (``False``). Is + called with the `attrs.Attribute` as the first argument and the + value as the second argument. + :param callable dict_factory: A callable to produce dictionaries from. For + example, to produce ordered dictionaries instead of normal Python + dictionaries, pass in ``collections.OrderedDict``. + :param bool retain_collection_types: Do not convert to ``list`` when + encountering an attribute whose type is ``tuple`` or ``set``. Only + meaningful if ``recurse`` is ``True``. + :param Optional[callable] value_serializer: A hook that is called for every + attribute or dict key/value. It receives the current instance, field + and value and must return the (updated) value. The hook is run *after* + the optional *filter* has been applied. + + :rtype: return type of *dict_factory* + + :raise attrs.exceptions.NotAnAttrsClassError: If *cls* is not an *attrs* + class. + + .. versionadded:: 16.0.0 *dict_factory* + .. versionadded:: 16.1.0 *retain_collection_types* + .. versionadded:: 20.3.0 *value_serializer* + .. versionadded:: 21.3.0 If a dict has a collection for a key, it is + serialized as a tuple. + """ + attrs = fields(inst.__class__) + rv = dict_factory() + for a in attrs: + v = getattr(inst, a.name) + if filter is not None and not filter(a, v): + continue + + if value_serializer is not None: + v = value_serializer(inst, a, v) + + if recurse is True: + if has(v.__class__): + rv[a.name] = asdict( + v, + recurse=True, + filter=filter, + dict_factory=dict_factory, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ) + elif isinstance(v, (tuple, list, set, frozenset)): + cf = v.__class__ if retain_collection_types is True else list + rv[a.name] = cf( + [ + _asdict_anything( + i, + is_key=False, + filter=filter, + dict_factory=dict_factory, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ) + for i in v + ] + ) + elif isinstance(v, dict): + df = dict_factory + rv[a.name] = df( + ( + _asdict_anything( + kk, + is_key=True, + filter=filter, + dict_factory=df, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ), + _asdict_anything( + vv, + is_key=False, + filter=filter, + dict_factory=df, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ), + ) + for kk, vv in v.items() + ) + else: + rv[a.name] = v + else: + rv[a.name] = v + return rv + + +def _asdict_anything( + val, + is_key, + filter, + dict_factory, + retain_collection_types, + value_serializer, +): + """ + ``asdict`` only works on attrs instances, this works on anything. + """ + if getattr(val.__class__, "__attrs_attrs__", None) is not None: + # Attrs class. + rv = asdict( + val, + recurse=True, + filter=filter, + dict_factory=dict_factory, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ) + elif isinstance(val, (tuple, list, set, frozenset)): + if retain_collection_types is True: + cf = val.__class__ + elif is_key: + cf = tuple + else: + cf = list + + rv = cf( + [ + _asdict_anything( + i, + is_key=False, + filter=filter, + dict_factory=dict_factory, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ) + for i in val + ] + ) + elif isinstance(val, dict): + df = dict_factory + rv = df( + ( + _asdict_anything( + kk, + is_key=True, + filter=filter, + dict_factory=df, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ), + _asdict_anything( + vv, + is_key=False, + filter=filter, + dict_factory=df, + retain_collection_types=retain_collection_types, + value_serializer=value_serializer, + ), + ) + for kk, vv in val.items() + ) + else: + rv = val + if value_serializer is not None: + rv = value_serializer(None, None, rv) + + return rv + + +def astuple( + inst, + recurse=True, + filter=None, + tuple_factory=tuple, + retain_collection_types=False, +): + """ + Return the *attrs* attribute values of *inst* as a tuple. + + Optionally recurse into other *attrs*-decorated classes. + + :param inst: Instance of an *attrs*-decorated class. + :param bool recurse: Recurse into classes that are also + *attrs*-decorated. + :param callable filter: A callable whose return code determines whether an + attribute or element is included (``True``) or dropped (``False``). Is + called with the `attrs.Attribute` as the first argument and the + value as the second argument. + :param callable tuple_factory: A callable to produce tuples from. For + example, to produce lists instead of tuples. + :param bool retain_collection_types: Do not convert to ``list`` + or ``dict`` when encountering an attribute which type is + ``tuple``, ``dict`` or ``set``. Only meaningful if ``recurse`` is + ``True``. + + :rtype: return type of *tuple_factory* + + :raise attrs.exceptions.NotAnAttrsClassError: If *cls* is not an *attrs* + class. + + .. versionadded:: 16.2.0 + """ + attrs = fields(inst.__class__) + rv = [] + retain = retain_collection_types # Very long. :/ + for a in attrs: + v = getattr(inst, a.name) + if filter is not None and not filter(a, v): + continue + if recurse is True: + if has(v.__class__): + rv.append( + astuple( + v, + recurse=True, + filter=filter, + tuple_factory=tuple_factory, + retain_collection_types=retain, + ) + ) + elif isinstance(v, (tuple, list, set, frozenset)): + cf = v.__class__ if retain is True else list + rv.append( + cf( + [ + astuple( + j, + recurse=True, + filter=filter, + tuple_factory=tuple_factory, + retain_collection_types=retain, + ) + if has(j.__class__) + else j + for j in v + ] + ) + ) + elif isinstance(v, dict): + df = v.__class__ if retain is True else dict + rv.append( + df( + ( + astuple( + kk, + tuple_factory=tuple_factory, + retain_collection_types=retain, + ) + if has(kk.__class__) + else kk, + astuple( + vv, + tuple_factory=tuple_factory, + retain_collection_types=retain, + ) + if has(vv.__class__) + else vv, + ) + for kk, vv in v.items() + ) + ) + else: + rv.append(v) + else: + rv.append(v) + + return rv if tuple_factory is list else tuple_factory(rv) + + +def has(cls): + """ + Check whether *cls* is a class with *attrs* attributes. + + :param type cls: Class to introspect. + :raise TypeError: If *cls* is not a class. + + :rtype: bool + """ + attrs = getattr(cls, "__attrs_attrs__", None) + if attrs is not None: + return True + + # No attrs, maybe it's a specialized generic (A[str])? + generic_base = get_generic_base(cls) + if generic_base is not None: + generic_attrs = getattr(generic_base, "__attrs_attrs__", None) + if generic_attrs is not None: + # Stick it on here for speed next time. + cls.__attrs_attrs__ = generic_attrs + return generic_attrs is not None + return False + + +def assoc(inst, **changes): + """ + Copy *inst* and apply *changes*. + + This is different from `evolve` that applies the changes to the arguments + that create the new instance. + + `evolve`'s behavior is preferable, but there are `edge cases`_ where it + doesn't work. Therefore `assoc` is deprecated, but will not be removed. + + .. _`edge cases`: https://github.com/python-attrs/attrs/issues/251 + + :param inst: Instance of a class with *attrs* attributes. + :param changes: Keyword changes in the new copy. + + :return: A copy of inst with *changes* incorporated. + + :raise attrs.exceptions.AttrsAttributeNotFoundError: If *attr_name* + couldn't be found on *cls*. + :raise attrs.exceptions.NotAnAttrsClassError: If *cls* is not an *attrs* + class. + + .. deprecated:: 17.1.0 + Use `attrs.evolve` instead if you can. + This function will not be removed du to the slightly different approach + compared to `attrs.evolve`. + """ + new = copy.copy(inst) + attrs = fields(inst.__class__) + for k, v in changes.items(): + a = getattr(attrs, k, NOTHING) + if a is NOTHING: + raise AttrsAttributeNotFoundError( + f"{k} is not an attrs attribute on {new.__class__}." + ) + _obj_setattr(new, k, v) + return new + + +def evolve(*args, **changes): + """ + Create a new instance, based on the first positional argument with + *changes* applied. + + :param inst: Instance of a class with *attrs* attributes. + :param changes: Keyword changes in the new copy. + + :return: A copy of inst with *changes* incorporated. + + :raise TypeError: If *attr_name* couldn't be found in the class + ``__init__``. + :raise attrs.exceptions.NotAnAttrsClassError: If *cls* is not an *attrs* + class. + + .. versionadded:: 17.1.0 + .. deprecated:: 23.1.0 + It is now deprecated to pass the instance using the keyword argument + *inst*. It will raise a warning until at least April 2024, after which + it will become an error. Always pass the instance as a positional + argument. + """ + # Try to get instance by positional argument first. + # Use changes otherwise and warn it'll break. + if args: + try: + (inst,) = args + except ValueError: + raise TypeError( + f"evolve() takes 1 positional argument, but {len(args)} " + "were given" + ) from None + else: + try: + inst = changes.pop("inst") + except KeyError: + raise TypeError( + "evolve() missing 1 required positional argument: 'inst'" + ) from None + + import warnings + + warnings.warn( + "Passing the instance per keyword argument is deprecated and " + "will stop working in, or after, April 2024.", + DeprecationWarning, + stacklevel=2, + ) + + cls = inst.__class__ + attrs = fields(cls) + for a in attrs: + if not a.init: + continue + attr_name = a.name # To deal with private attributes. + init_name = a.alias + if init_name not in changes: + changes[init_name] = getattr(inst, attr_name) + + return cls(**changes) + + +def resolve_types( + cls, globalns=None, localns=None, attribs=None, include_extras=True +): + """ + Resolve any strings and forward annotations in type annotations. + + This is only required if you need concrete types in `Attribute`'s *type* + field. In other words, you don't need to resolve your types if you only + use them for static type checking. + + With no arguments, names will be looked up in the module in which the class + was created. If this is not what you want, e.g. if the name only exists + inside a method, you may pass *globalns* or *localns* to specify other + dictionaries in which to look up these names. See the docs of + `typing.get_type_hints` for more details. + + :param type cls: Class to resolve. + :param Optional[dict] globalns: Dictionary containing global variables. + :param Optional[dict] localns: Dictionary containing local variables. + :param Optional[list] attribs: List of attribs for the given class. + This is necessary when calling from inside a ``field_transformer`` + since *cls* is not an *attrs* class yet. + :param bool include_extras: Resolve more accurately, if possible. + Pass ``include_extras`` to ``typing.get_hints``, if supported by the + typing module. On supported Python versions (3.9+), this resolves the + types more accurately. + + :raise TypeError: If *cls* is not a class. + :raise attrs.exceptions.NotAnAttrsClassError: If *cls* is not an *attrs* + class and you didn't pass any attribs. + :raise NameError: If types cannot be resolved because of missing variables. + + :returns: *cls* so you can use this function also as a class decorator. + Please note that you have to apply it **after** `attrs.define`. That + means the decorator has to come in the line **before** `attrs.define`. + + .. versionadded:: 20.1.0 + .. versionadded:: 21.1.0 *attribs* + .. versionadded:: 23.1.0 *include_extras* + + """ + # Since calling get_type_hints is expensive we cache whether we've + # done it already. + if getattr(cls, "__attrs_types_resolved__", None) != cls: + import typing + + kwargs = {"globalns": globalns, "localns": localns} + + if PY_3_9_PLUS: + kwargs["include_extras"] = include_extras + + hints = typing.get_type_hints(cls, **kwargs) + for field in fields(cls) if attribs is None else attribs: + if field.name in hints: + # Since fields have been frozen we must work around it. + _obj_setattr(field, "type", hints[field.name]) + # We store the class we resolved so that subclasses know they haven't + # been resolved. + cls.__attrs_types_resolved__ = cls + + # Return the class so you can use it as a decorator too. + return cls |