# --------------------------------------------------------------------------------------
# Copyright (c) 2021-2023, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
# --------------------------------------------------------------------------------------
import collections.abc
from collections import defaultdict
from typing import Any, ClassVar, MutableMapping, Type
from ..catom import Member
from ..dict import DefaultDict, Dict as ADict
from ..instance import Instance
from ..list import List as AList
from ..scalars import Bool, Bytes, Callable as ACallable, Float, Int, Str, Value
from ..set import Set as ASet
from ..subclass import Subclass
from ..tuple import FixedTuple, Tuple as ATuple
from ..typed import Typed
from ..typing_utils import extract_types, get_args, is_optional
from .member_modifiers import set_default
_NO_DEFAULT = object()
_TYPE_TO_MEMBER = {
bool: Bool,
int: Int,
float: Float,
str: Str,
bytes: Bytes,
list: AList,
dict: ADict,
defaultdict: DefaultDict,
set: ASet,
tuple: ATuple,
collections.abc.Callable: ACallable,
}
[docs]
def generate_member_from_type_or_generic(
type_generic: Any, default: Any, annotate_type_containers: int
) -> Member:
"""Generate a member from a type or generic alias."""
types = extract_types(type_generic)
parameters = get_args(type_generic)
m_kwargs = {}
m_cls: Type[Member]
if any(
isinstance(t, type) and issubclass(t, Member) for t in types
) and not isinstance(default, Member):
raise ValueError(
"Member subclasses cannot be used as annotations without "
"specifying a default value for the attribute."
)
elif object in types or Any in types:
m_cls = Value
parameters = ()
# Int, Float, Str, Bytes, List, Dict, Set, Tuple, Bool, Callable
elif len(types) == 1 and types[0] in _TYPE_TO_MEMBER:
t = types[0]
m_cls = _TYPE_TO_MEMBER[t]
if annotate_type_containers and t in (
list,
dict,
collections.defaultdict,
set,
tuple,
):
# We can only validate homogeneous tuple so far so we ignore other cases
if t is tuple:
if (...) in parameters:
parameters = (parameters[0],)
else:
m_cls = FixedTuple
parameters = tuple(
generate_member_from_type_or_generic(
t, _NO_DEFAULT, annotate_type_containers - 1
)
if t not in (Any, object)
else None
for t in parameters
)
else:
parameters = ()
# The value was annotated with Type[T] so we use a subclass
elif all(t is type for t in types):
m_cls = Subclass
assert len(parameters) == 1
parameters = extract_types(parameters[0])
else:
# Only a metaclass can implement __instancecheck__ so we check for an
# implementation differing from type.__instancecheck__ and use Instance
# if we find one and otherwise Typed.
opt, filtered_types = is_optional(types)
if (
len(filtered_types) == 1
and type(filtered_types[0]).__instancecheck__ is type.__instancecheck__
):
m_cls = Typed
else:
m_cls = Instance
parameters = (filtered_types,)
m_kwargs["optional"] = opt
if opt and default not in (_NO_DEFAULT, None):
raise ValueError(
"Members requiring Instance(optional=True) cannot have "
"a non-None default value."
)
elif not opt and default is not _NO_DEFAULT:
raise ValueError("Members requiring Instance cannot have a default value.")
# Instance does not have a default keyword so turn a None default into the
# equivalent no default.
default = _NO_DEFAULT
if default is not _NO_DEFAULT:
m_kwargs["default"] = default
return m_cls(*parameters, **m_kwargs)
[docs]
def generate_members_from_cls_namespace(
cls_name: str, namespace: MutableMapping[str, Any], annotate_type_containers: int
) -> None:
"""Generate the member corresponding to a type annotation."""
annotations = namespace["__annotations__"]
for name, ann in annotations.items():
default = namespace.get(name, _NO_DEFAULT)
# We skip field for which a member was already provided or annotations
# corresponding to class variables.
if isinstance(default, (Member, set_default)):
# Allow string annotations for members
if isinstance(ann, str):
continue
types = extract_types(ann)
if len(types) != 1 or not issubclass(types[0], Member):
raise TypeError(
f"Field '{name}' of '{cls_name}' is assigned a Member-like value "
"but its annotation is not Member compatible"
)
continue
# We also skip fields annotated as class variables.
elif getattr(ann, "__origin__", None) is ClassVar:
continue
try:
namespace[name] = generate_member_from_type_or_generic(
ann, default, annotate_type_containers
)
except ValueError as e:
raise ValueError(
"Encountered an issue when generating a member for field "
f"'{name}' of '{cls_name}'."
) from e