Current File : //lib/python3/dist-packages/pyrsistent/_field_common.py
from pyrsistent._checked_types import (
CheckedPMap,
CheckedPSet,
CheckedPVector,
CheckedType,
InvariantException,
_restore_pickle,
get_type,
maybe_parse_user_type,
maybe_parse_many_user_types,
)
from pyrsistent._checked_types import optional as optional_type
from pyrsistent._checked_types import wrap_invariant
import inspect
def set_fields(dct, bases, name):
dct[name] = dict(sum([list(b.__dict__.get(name, {}).items()) for b in bases], []))
for k, v in list(dct.items()):
if isinstance(v, _PField):
dct[name][k] = v
del dct[k]
def check_global_invariants(subject, invariants):
error_codes = tuple(error_code for is_ok, error_code in
(invariant(subject) for invariant in invariants) if not is_ok)
if error_codes:
raise InvariantException(error_codes, (), 'Global invariant failed')
def serialize(serializer, format, value):
if isinstance(value, CheckedType) and serializer is PFIELD_NO_SERIALIZER:
return value.serialize(format)
return serializer(format, value)
def check_type(destination_cls, field, name, value):
if field.type and not any(isinstance(value, get_type(t)) for t in field.type):
actual_type = type(value)
message = "Invalid type for field {0}.{1}, was {2}".format(destination_cls.__name__, name, actual_type.__name__)
raise PTypeError(destination_cls, name, field.type, actual_type, message)
def is_type_cls(type_cls, field_type):
if type(field_type) is set:
return True
types = tuple(field_type)
if len(types) == 0:
return False
return issubclass(get_type(types[0]), type_cls)
def is_field_ignore_extra_complaint(type_cls, field, ignore_extra):
# ignore_extra param has default False value, for speed purpose no need to propagate False
if not ignore_extra:
return False
if not is_type_cls(type_cls, field.type):
return False
return 'ignore_extra' in inspect.signature(field.factory).parameters
class _PField(object):
__slots__ = ('type', 'invariant', 'initial', 'mandatory', '_factory', 'serializer')
def __init__(self, type, invariant, initial, mandatory, factory, serializer):
self.type = type
self.invariant = invariant
self.initial = initial
self.mandatory = mandatory
self._factory = factory
self.serializer = serializer
@property
def factory(self):
# If no factory is specified and the type is another CheckedType use the factory method of that CheckedType
if self._factory is PFIELD_NO_FACTORY and len(self.type) == 1:
typ = get_type(tuple(self.type)[0])
if issubclass(typ, CheckedType):
return typ.create
return self._factory
PFIELD_NO_TYPE = ()
PFIELD_NO_INVARIANT = lambda _: (True, None)
PFIELD_NO_FACTORY = lambda x: x
PFIELD_NO_INITIAL = object()
PFIELD_NO_SERIALIZER = lambda _, value: value
def field(type=PFIELD_NO_TYPE, invariant=PFIELD_NO_INVARIANT, initial=PFIELD_NO_INITIAL,
mandatory=False, factory=PFIELD_NO_FACTORY, serializer=PFIELD_NO_SERIALIZER):
"""
Field specification factory for :py:class:`PRecord`.
:param type: a type or iterable with types that are allowed for this field
:param invariant: a function specifying an invariant that must hold for the field
:param initial: value of field if not specified when instantiating the record
:param mandatory: boolean specifying if the field is mandatory or not
:param factory: function called when field is set.
:param serializer: function that returns a serialized version of the field
"""
# NB: We have to check this predicate separately from the predicates in
# `maybe_parse_user_type` et al. because this one is related to supporting
# the argspec for `field`, while those are related to supporting the valid
# ways to specify types.
# Multiple types must be passed in one of the following containers. Note
# that a type that is a subclass of one of these containers, like a
# `collections.namedtuple`, will work as expected, since we check
# `isinstance` and not `issubclass`.
if isinstance(type, (list, set, tuple)):
types = set(maybe_parse_many_user_types(type))
else:
types = set(maybe_parse_user_type(type))
invariant_function = wrap_invariant(invariant) if invariant != PFIELD_NO_INVARIANT and callable(invariant) else invariant
field = _PField(type=types, invariant=invariant_function, initial=initial,
mandatory=mandatory, factory=factory, serializer=serializer)
_check_field_parameters(field)
return field
def _check_field_parameters(field):
for t in field.type:
if not isinstance(t, type) and not isinstance(t, str):
raise TypeError('Type parameter expected, not {0}'.format(type(t)))
if field.initial is not PFIELD_NO_INITIAL and \
not callable(field.initial) and \
field.type and not any(isinstance(field.initial, t) for t in field.type):
raise TypeError('Initial has invalid type {0}'.format(type(field.initial)))
if not callable(field.invariant):
raise TypeError('Invariant must be callable')
if not callable(field.factory):
raise TypeError('Factory must be callable')
if not callable(field.serializer):
raise TypeError('Serializer must be callable')
class PTypeError(TypeError):
"""
Raised when trying to assign a value with a type that doesn't match the declared type.
Attributes:
source_class -- The class of the record
field -- Field name
expected_types -- Types allowed for the field
actual_type -- The non matching type
"""
def __init__(self, source_class, field, expected_types, actual_type, *args, **kwargs):
super(PTypeError, self).__init__(*args, **kwargs)
self.source_class = source_class
self.field = field
self.expected_types = expected_types
self.actual_type = actual_type
SEQ_FIELD_TYPE_SUFFIXES = {
CheckedPVector: "PVector",
CheckedPSet: "PSet",
}
# Global dictionary to hold auto-generated field types: used for unpickling
_seq_field_types = {}
def _restore_seq_field_pickle(checked_class, item_type, data):
"""Unpickling function for auto-generated PVec/PSet field types."""
type_ = _seq_field_types[checked_class, item_type]
return _restore_pickle(type_, data)
def _types_to_names(types):
"""Convert a tuple of types to a human-readable string."""
return "".join(get_type(typ).__name__.capitalize() for typ in types)
def _make_seq_field_type(checked_class, item_type, item_invariant):
"""Create a subclass of the given checked class with the given item type."""
type_ = _seq_field_types.get((checked_class, item_type))
if type_ is not None:
return type_
class TheType(checked_class):
__type__ = item_type
__invariant__ = item_invariant
def __reduce__(self):
return (_restore_seq_field_pickle,
(checked_class, item_type, list(self)))
suffix = SEQ_FIELD_TYPE_SUFFIXES[checked_class]
TheType.__name__ = _types_to_names(TheType._checked_types) + suffix
_seq_field_types[checked_class, item_type] = TheType
return TheType
def _sequence_field(checked_class, item_type, optional, initial,
invariant=PFIELD_NO_INVARIANT,
item_invariant=PFIELD_NO_INVARIANT):
"""
Create checked field for either ``PSet`` or ``PVector``.
:param checked_class: ``CheckedPSet`` or ``CheckedPVector``.
:param item_type: The required type for the items in the set.
:param optional: If true, ``None`` can be used as a value for
this field.
:param initial: Initial value to pass to factory.
:return: A ``field`` containing a checked class.
"""
TheType = _make_seq_field_type(checked_class, item_type, item_invariant)
if optional:
def factory(argument, _factory_fields=None, ignore_extra=False):
if argument is None:
return None
else:
return TheType.create(argument, _factory_fields=_factory_fields, ignore_extra=ignore_extra)
else:
factory = TheType.create
return field(type=optional_type(TheType) if optional else TheType,
factory=factory, mandatory=True,
invariant=invariant,
initial=factory(initial))
def pset_field(item_type, optional=False, initial=(),
invariant=PFIELD_NO_INVARIANT,
item_invariant=PFIELD_NO_INVARIANT):
"""
Create checked ``PSet`` field.
:param item_type: The required type for the items in the set.
:param optional: If true, ``None`` can be used as a value for
this field.
:param initial: Initial value to pass to factory if no value is given
for the field.
:return: A ``field`` containing a ``CheckedPSet`` of the given type.
"""
return _sequence_field(CheckedPSet, item_type, optional, initial,
invariant=invariant,
item_invariant=item_invariant)
def pvector_field(item_type, optional=False, initial=(),
invariant=PFIELD_NO_INVARIANT,
item_invariant=PFIELD_NO_INVARIANT):
"""
Create checked ``PVector`` field.
:param item_type: The required type for the items in the vector.
:param optional: If true, ``None`` can be used as a value for
this field.
:param initial: Initial value to pass to factory if no value is given
for the field.
:return: A ``field`` containing a ``CheckedPVector`` of the given type.
"""
return _sequence_field(CheckedPVector, item_type, optional, initial,
invariant=invariant,
item_invariant=item_invariant)
_valid = lambda item: (True, "")
# Global dictionary to hold auto-generated field types: used for unpickling
_pmap_field_types = {}
def _restore_pmap_field_pickle(key_type, value_type, data):
"""Unpickling function for auto-generated PMap field types."""
type_ = _pmap_field_types[key_type, value_type]
return _restore_pickle(type_, data)
def _make_pmap_field_type(key_type, value_type):
"""Create a subclass of CheckedPMap with the given key and value types."""
type_ = _pmap_field_types.get((key_type, value_type))
if type_ is not None:
return type_
class TheMap(CheckedPMap):
__key_type__ = key_type
__value_type__ = value_type
def __reduce__(self):
return (_restore_pmap_field_pickle,
(self.__key_type__, self.__value_type__, dict(self)))
TheMap.__name__ = "{0}To{1}PMap".format(
_types_to_names(TheMap._checked_key_types),
_types_to_names(TheMap._checked_value_types))
_pmap_field_types[key_type, value_type] = TheMap
return TheMap
def pmap_field(key_type, value_type, optional=False, invariant=PFIELD_NO_INVARIANT):
"""
Create a checked ``PMap`` field.
:param key: The required type for the keys of the map.
:param value: The required type for the values of the map.
:param optional: If true, ``None`` can be used as a value for
this field.
:param invariant: Pass-through to ``field``.
:return: A ``field`` containing a ``CheckedPMap``.
"""
TheMap = _make_pmap_field_type(key_type, value_type)
if optional:
def factory(argument):
if argument is None:
return None
else:
return TheMap.create(argument)
else:
factory = TheMap.create
return field(mandatory=True, initial=TheMap(),
type=optional_type(TheMap) if optional else TheMap,
factory=factory, invariant=invariant)
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