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tldr: refactoring

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Romain J 2019-12-16 18:12:10 +01:00
commit f42b2194cd
2881 changed files with 568359 additions and 388 deletions
venv/lib/python3.7/site-packages/sqlalchemy/ext/declarative
__init__.pyapi.pybase.pyclsregistry.py

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# ext/declarative/__init__.py
# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
from .api import AbstractConcreteBase
from .api import as_declarative
from .api import comparable_using
from .api import ConcreteBase
from .api import declarative_base
from .api import DeclarativeMeta
from .api import declared_attr
from .api import DeferredReflection
from .api import has_inherited_table
from .api import instrument_declarative
from .api import synonym_for
__all__ = [
"declarative_base",
"synonym_for",
"has_inherited_table",
"comparable_using",
"instrument_declarative",
"declared_attr",
"as_declarative",
"ConcreteBase",
"AbstractConcreteBase",
"DeclarativeMeta",
"DeferredReflection",
]

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# ext/declarative/api.py
# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Public API functions and helpers for declarative."""
import re
import weakref
from .base import _add_attribute
from .base import _as_declarative
from .base import _declarative_constructor
from .base import _DeferredMapperConfig
from .base import _del_attribute
from .clsregistry import _class_resolver
from ... import exc
from ... import inspection
from ... import util
from ...orm import attributes
from ...orm import comparable_property
from ...orm import exc as orm_exc
from ...orm import interfaces
from ...orm import properties
from ...orm import synonym as _orm_synonym
from ...orm.base import _inspect_mapped_class
from ...orm.base import _mapper_or_none
from ...orm.util import polymorphic_union
from ...schema import MetaData
from ...schema import Table
from ...util import hybridmethod
from ...util import hybridproperty
from ...util import OrderedDict
def instrument_declarative(cls, registry, metadata):
"""Given a class, configure the class declaratively,
using the given registry, which can be any dictionary, and
MetaData object.
"""
if "_decl_class_registry" in cls.__dict__:
raise exc.InvalidRequestError(
"Class %r already has been " "instrumented declaratively" % cls
)
cls._decl_class_registry = registry
cls.metadata = metadata
_as_declarative(cls, cls.__name__, cls.__dict__)
def has_inherited_table(cls):
"""Given a class, return True if any of the classes it inherits from has a
mapped table, otherwise return False.
This is used in declarative mixins to build attributes that behave
differently for the base class vs. a subclass in an inheritance
hierarchy.
.. seealso::
:ref:`decl_mixin_inheritance`
"""
for class_ in cls.__mro__[1:]:
if getattr(class_, "__table__", None) is not None:
return True
return False
class DeclarativeMeta(type):
def __init__(cls, classname, bases, dict_):
if "_decl_class_registry" not in cls.__dict__:
_as_declarative(cls, classname, cls.__dict__)
type.__init__(cls, classname, bases, dict_)
def __setattr__(cls, key, value):
_add_attribute(cls, key, value)
def __delattr__(cls, key):
_del_attribute(cls, key)
def synonym_for(name, map_column=False):
"""Decorator that produces an :func:`.orm.synonym` attribute in conjunction
with a Python descriptor.
The function being decorated is passed to :func:`.orm.synonym` as the
:paramref:`.orm.synonym.descriptor` parameter::
class MyClass(Base):
__tablename__ = 'my_table'
id = Column(Integer, primary_key=True)
_job_status = Column("job_status", String(50))
@synonym_for("job_status")
@property
def job_status(self):
return "Status: %s" % self._job_status
The :ref:`hybrid properties <mapper_hybrids>` feature of SQLAlchemy
is typically preferred instead of synonyms, which is a more legacy
feature.
.. seealso::
:ref:`synonyms` - Overview of synonyms
:func:`.orm.synonym` - the mapper-level function
:ref:`mapper_hybrids` - The Hybrid Attribute extension provides an
updated approach to augmenting attribute behavior more flexibly than
can be achieved with synonyms.
"""
def decorate(fn):
return _orm_synonym(name, map_column=map_column, descriptor=fn)
return decorate
def comparable_using(comparator_factory):
"""Decorator, allow a Python @property to be used in query criteria.
This is a decorator front end to
:func:`~sqlalchemy.orm.comparable_property` that passes
through the comparator_factory and the function being decorated::
@comparable_using(MyComparatorType)
@property
def prop(self):
return 'special sauce'
The regular ``comparable_property()`` is also usable directly in a
declarative setting and may be convenient for read/write properties::
prop = comparable_property(MyComparatorType)
"""
def decorate(fn):
return comparable_property(comparator_factory, fn)
return decorate
class declared_attr(interfaces._MappedAttribute, property):
"""Mark a class-level method as representing the definition of
a mapped property or special declarative member name.
@declared_attr turns the attribute into a scalar-like
property that can be invoked from the uninstantiated class.
Declarative treats attributes specifically marked with
@declared_attr as returning a construct that is specific
to mapping or declarative table configuration. The name
of the attribute is that of what the non-dynamic version
of the attribute would be.
@declared_attr is more often than not applicable to mixins,
to define relationships that are to be applied to different
implementors of the class::
class ProvidesUser(object):
"A mixin that adds a 'user' relationship to classes."
@declared_attr
def user(self):
return relationship("User")
It also can be applied to mapped classes, such as to provide
a "polymorphic" scheme for inheritance::
class Employee(Base):
id = Column(Integer, primary_key=True)
type = Column(String(50), nullable=False)
@declared_attr
def __tablename__(cls):
return cls.__name__.lower()
@declared_attr
def __mapper_args__(cls):
if cls.__name__ == 'Employee':
return {
"polymorphic_on":cls.type,
"polymorphic_identity":"Employee"
}
else:
return {"polymorphic_identity":cls.__name__}
"""
def __init__(self, fget, cascading=False):
super(declared_attr, self).__init__(fget)
self.__doc__ = fget.__doc__
self._cascading = cascading
def __get__(desc, self, cls):
reg = cls.__dict__.get("_sa_declared_attr_reg", None)
if reg is None:
if (
not re.match(r"^__.+__$", desc.fget.__name__)
and attributes.manager_of_class(cls) is None
):
util.warn(
"Unmanaged access of declarative attribute %s from "
"non-mapped class %s" % (desc.fget.__name__, cls.__name__)
)
return desc.fget(cls)
elif desc in reg:
return reg[desc]
else:
reg[desc] = obj = desc.fget(cls)
return obj
@hybridmethod
def _stateful(cls, **kw):
return _stateful_declared_attr(**kw)
@hybridproperty
def cascading(cls):
"""Mark a :class:`.declared_attr` as cascading.
This is a special-use modifier which indicates that a column
or MapperProperty-based declared attribute should be configured
distinctly per mapped subclass, within a mapped-inheritance scenario.
.. warning::
The :attr:`.declared_attr.cascading` modifier has several
limitations:
* The flag **only** applies to the use of :class:`.declared_attr`
on declarative mixin classes and ``__abstract__`` classes; it
currently has no effect when used on a mapped class directly.
* The flag **only** applies to normally-named attributes, e.g.
not any special underscore attributes such as ``__tablename__``.
On these attributes it has **no** effect.
* The flag currently **does not allow further overrides** down
the class hierarchy; if a subclass tries to override the
attribute, a warning is emitted and the overridden attribute
is skipped. This is a limitation that it is hoped will be
resolved at some point.
Below, both MyClass as well as MySubClass will have a distinct
``id`` Column object established::
class HasIdMixin(object):
@declared_attr.cascading
def id(cls):
if has_inherited_table(cls):
return Column(
ForeignKey('myclass.id'), primary_key=True)
else:
return Column(Integer, primary_key=True)
class MyClass(HasIdMixin, Base):
__tablename__ = 'myclass'
# ...
class MySubClass(MyClass):
""
# ...
The behavior of the above configuration is that ``MySubClass``
will refer to both its own ``id`` column as well as that of
``MyClass`` underneath the attribute named ``some_id``.
.. seealso::
:ref:`declarative_inheritance`
:ref:`mixin_inheritance_columns`
"""
return cls._stateful(cascading=True)
class _stateful_declared_attr(declared_attr):
def __init__(self, **kw):
self.kw = kw
def _stateful(self, **kw):
new_kw = self.kw.copy()
new_kw.update(kw)
return _stateful_declared_attr(**new_kw)
def __call__(self, fn):
return declared_attr(fn, **self.kw)
def declarative_base(
bind=None,
metadata=None,
mapper=None,
cls=object,
name="Base",
constructor=_declarative_constructor,
class_registry=None,
metaclass=DeclarativeMeta,
):
r"""Construct a base class for declarative class definitions.
The new base class will be given a metaclass that produces
appropriate :class:`~sqlalchemy.schema.Table` objects and makes
the appropriate :func:`~sqlalchemy.orm.mapper` calls based on the
information provided declaratively in the class and any subclasses
of the class.
:param bind: An optional
:class:`~sqlalchemy.engine.Connectable`, will be assigned
the ``bind`` attribute on the :class:`~sqlalchemy.schema.MetaData`
instance.
:param metadata:
An optional :class:`~sqlalchemy.schema.MetaData` instance. All
:class:`~sqlalchemy.schema.Table` objects implicitly declared by
subclasses of the base will share this MetaData. A MetaData instance
will be created if none is provided. The
:class:`~sqlalchemy.schema.MetaData` instance will be available via the
`metadata` attribute of the generated declarative base class.
:param mapper:
An optional callable, defaults to :func:`~sqlalchemy.orm.mapper`. Will
be used to map subclasses to their Tables.
:param cls:
Defaults to :class:`object`. A type to use as the base for the generated
declarative base class. May be a class or tuple of classes.
:param name:
Defaults to ``Base``. The display name for the generated
class. Customizing this is not required, but can improve clarity in
tracebacks and debugging.
:param constructor:
Defaults to
:func:`~sqlalchemy.ext.declarative.base._declarative_constructor`, an
__init__ implementation that assigns \**kwargs for declared
fields and relationships to an instance. If ``None`` is supplied,
no __init__ will be provided and construction will fall back to
cls.__init__ by way of the normal Python semantics.
:param class_registry: optional dictionary that will serve as the
registry of class names-> mapped classes when string names
are used to identify classes inside of :func:`.relationship`
and others. Allows two or more declarative base classes
to share the same registry of class names for simplified
inter-base relationships.
:param metaclass:
Defaults to :class:`.DeclarativeMeta`. A metaclass or __metaclass__
compatible callable to use as the meta type of the generated
declarative base class.
.. versionchanged:: 1.1 if :paramref:`.declarative_base.cls` is a
single class (rather than a tuple), the constructed base class will
inherit its docstring.
.. seealso::
:func:`.as_declarative`
"""
lcl_metadata = metadata or MetaData()
if bind:
lcl_metadata.bind = bind
if class_registry is None:
class_registry = weakref.WeakValueDictionary()
bases = not isinstance(cls, tuple) and (cls,) or cls
class_dict = dict(
_decl_class_registry=class_registry, metadata=lcl_metadata
)
if isinstance(cls, type):
class_dict["__doc__"] = cls.__doc__
if constructor:
class_dict["__init__"] = constructor
if mapper:
class_dict["__mapper_cls__"] = mapper
return metaclass(name, bases, class_dict)
def as_declarative(**kw):
"""
Class decorator for :func:`.declarative_base`.
Provides a syntactical shortcut to the ``cls`` argument
sent to :func:`.declarative_base`, allowing the base class
to be converted in-place to a "declarative" base::
from sqlalchemy.ext.declarative import as_declarative
@as_declarative()
class Base(object):
@declared_attr
def __tablename__(cls):
return cls.__name__.lower()
id = Column(Integer, primary_key=True)
class MyMappedClass(Base):
# ...
All keyword arguments passed to :func:`.as_declarative` are passed
along to :func:`.declarative_base`.
.. seealso::
:func:`.declarative_base`
"""
def decorate(cls):
kw["cls"] = cls
kw["name"] = cls.__name__
return declarative_base(**kw)
return decorate
class ConcreteBase(object):
"""A helper class for 'concrete' declarative mappings.
:class:`.ConcreteBase` will use the :func:`.polymorphic_union`
function automatically, against all tables mapped as a subclass
to this class. The function is called via the
``__declare_last__()`` function, which is essentially
a hook for the :meth:`.after_configured` event.
:class:`.ConcreteBase` produces a mapped
table for the class itself. Compare to :class:`.AbstractConcreteBase`,
which does not.
Example::
from sqlalchemy.ext.declarative import ConcreteBase
class Employee(ConcreteBase, Base):
__tablename__ = 'employee'
employee_id = Column(Integer, primary_key=True)
name = Column(String(50))
__mapper_args__ = {
'polymorphic_identity':'employee',
'concrete':True}
class Manager(Employee):
__tablename__ = 'manager'
employee_id = Column(Integer, primary_key=True)
name = Column(String(50))
manager_data = Column(String(40))
__mapper_args__ = {
'polymorphic_identity':'manager',
'concrete':True}
.. seealso::
:class:`.AbstractConcreteBase`
:ref:`concrete_inheritance`
:ref:`inheritance_concrete_helpers`
"""
@classmethod
def _create_polymorphic_union(cls, mappers):
return polymorphic_union(
OrderedDict(
(mp.polymorphic_identity, mp.local_table) for mp in mappers
),
"type",
"pjoin",
)
@classmethod
def __declare_first__(cls):
m = cls.__mapper__
if m.with_polymorphic:
return
mappers = list(m.self_and_descendants)
pjoin = cls._create_polymorphic_union(mappers)
m._set_with_polymorphic(("*", pjoin))
m._set_polymorphic_on(pjoin.c.type)
class AbstractConcreteBase(ConcreteBase):
"""A helper class for 'concrete' declarative mappings.
:class:`.AbstractConcreteBase` will use the :func:`.polymorphic_union`
function automatically, against all tables mapped as a subclass
to this class. The function is called via the
``__declare_last__()`` function, which is essentially
a hook for the :meth:`.after_configured` event.
:class:`.AbstractConcreteBase` does produce a mapped class
for the base class, however it is not persisted to any table; it
is instead mapped directly to the "polymorphic" selectable directly
and is only used for selecting. Compare to :class:`.ConcreteBase`,
which does create a persisted table for the base class.
.. note::
The :class:`.AbstractConcreteBase` class does not intend to set up the
mapping for the base class until all the subclasses have been defined,
as it needs to create a mapping against a selectable that will include
all subclass tables. In order to achieve this, it waits for the
**mapper configuration event** to occur, at which point it scans
through all the configured subclasses and sets up a mapping that will
query against all subclasses at once.
While this event is normally invoked automatically, in the case of
:class:`.AbstractConcreteBase`, it may be necessary to invoke it
explicitly after **all** subclass mappings are defined, if the first
operation is to be a query against this base class. To do so, invoke
:func:`.configure_mappers` once all the desired classes have been
configured::
from sqlalchemy.orm import configure_mappers
configure_mappers()
.. seealso::
:func:`.orm.configure_mappers`
Example::
from sqlalchemy.ext.declarative import AbstractConcreteBase
class Employee(AbstractConcreteBase, Base):
pass
class Manager(Employee):
__tablename__ = 'manager'
employee_id = Column(Integer, primary_key=True)
name = Column(String(50))
manager_data = Column(String(40))
__mapper_args__ = {
'polymorphic_identity':'manager',
'concrete':True}
configure_mappers()
The abstract base class is handled by declarative in a special way;
at class configuration time, it behaves like a declarative mixin
or an ``__abstract__`` base class. Once classes are configured
and mappings are produced, it then gets mapped itself, but
after all of its descendants. This is a very unique system of mapping
not found in any other SQLAlchemy system.
Using this approach, we can specify columns and properties
that will take place on mapped subclasses, in the way that
we normally do as in :ref:`declarative_mixins`::
class Company(Base):
__tablename__ = 'company'
id = Column(Integer, primary_key=True)
class Employee(AbstractConcreteBase, Base):
employee_id = Column(Integer, primary_key=True)
@declared_attr
def company_id(cls):
return Column(ForeignKey('company.id'))
@declared_attr
def company(cls):
return relationship("Company")
class Manager(Employee):
__tablename__ = 'manager'
name = Column(String(50))
manager_data = Column(String(40))
__mapper_args__ = {
'polymorphic_identity':'manager',
'concrete':True}
configure_mappers()
When we make use of our mappings however, both ``Manager`` and
``Employee`` will have an independently usable ``.company`` attribute::
session.query(Employee).filter(Employee.company.has(id=5))
.. versionchanged:: 1.0.0 - The mechanics of :class:`.AbstractConcreteBase`
have been reworked to support relationships established directly
on the abstract base, without any special configurational steps.
.. seealso::
:class:`.ConcreteBase`
:ref:`concrete_inheritance`
:ref:`inheritance_concrete_helpers`
"""
__no_table__ = True
@classmethod
def __declare_first__(cls):
cls._sa_decl_prepare_nocascade()
@classmethod
def _sa_decl_prepare_nocascade(cls):
if getattr(cls, "__mapper__", None):
return
to_map = _DeferredMapperConfig.config_for_cls(cls)
# can't rely on 'self_and_descendants' here
# since technically an immediate subclass
# might not be mapped, but a subclass
# may be.
mappers = []
stack = list(cls.__subclasses__())
while stack:
klass = stack.pop()
stack.extend(klass.__subclasses__())
mn = _mapper_or_none(klass)
if mn is not None:
mappers.append(mn)
pjoin = cls._create_polymorphic_union(mappers)
# For columns that were declared on the class, these
# are normally ignored with the "__no_table__" mapping,
# unless they have a different attribute key vs. col name
# and are in the properties argument.
# In that case, ensure we update the properties entry
# to the correct column from the pjoin target table.
declared_cols = set(to_map.declared_columns)
for k, v in list(to_map.properties.items()):
if v in declared_cols:
to_map.properties[k] = pjoin.c[v.key]
to_map.local_table = pjoin
m_args = to_map.mapper_args_fn or dict
def mapper_args():
args = m_args()
args["polymorphic_on"] = pjoin.c.type
return args
to_map.mapper_args_fn = mapper_args
m = to_map.map()
for scls in cls.__subclasses__():
sm = _mapper_or_none(scls)
if sm and sm.concrete and cls in scls.__bases__:
sm._set_concrete_base(m)
@classmethod
def _sa_raise_deferred_config(cls):
raise orm_exc.UnmappedClassError(
cls,
msg="Class %s is a subclass of AbstractConcreteBase and "
"has a mapping pending until all subclasses are defined. "
"Call the sqlalchemy.orm.configure_mappers() function after "
"all subclasses have been defined to "
"complete the mapping of this class."
% orm_exc._safe_cls_name(cls),
)
class DeferredReflection(object):
"""A helper class for construction of mappings based on
a deferred reflection step.
Normally, declarative can be used with reflection by
setting a :class:`.Table` object using autoload=True
as the ``__table__`` attribute on a declarative class.
The caveat is that the :class:`.Table` must be fully
reflected, or at the very least have a primary key column,
at the point at which a normal declarative mapping is
constructed, meaning the :class:`.Engine` must be available
at class declaration time.
The :class:`.DeferredReflection` mixin moves the construction
of mappers to be at a later point, after a specific
method is called which first reflects all :class:`.Table`
objects created so far. Classes can define it as such::
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.ext.declarative import DeferredReflection
Base = declarative_base()
class MyClass(DeferredReflection, Base):
__tablename__ = 'mytable'
Above, ``MyClass`` is not yet mapped. After a series of
classes have been defined in the above fashion, all tables
can be reflected and mappings created using
:meth:`.prepare`::
engine = create_engine("someengine://...")
DeferredReflection.prepare(engine)
The :class:`.DeferredReflection` mixin can be applied to individual
classes, used as the base for the declarative base itself,
or used in a custom abstract class. Using an abstract base
allows that only a subset of classes to be prepared for a
particular prepare step, which is necessary for applications
that use more than one engine. For example, if an application
has two engines, you might use two bases, and prepare each
separately, e.g.::
class ReflectedOne(DeferredReflection, Base):
__abstract__ = True
class ReflectedTwo(DeferredReflection, Base):
__abstract__ = True
class MyClass(ReflectedOne):
__tablename__ = 'mytable'
class MyOtherClass(ReflectedOne):
__tablename__ = 'myothertable'
class YetAnotherClass(ReflectedTwo):
__tablename__ = 'yetanothertable'
# ... etc.
Above, the class hierarchies for ``ReflectedOne`` and
``ReflectedTwo`` can be configured separately::
ReflectedOne.prepare(engine_one)
ReflectedTwo.prepare(engine_two)
"""
@classmethod
def prepare(cls, engine):
"""Reflect all :class:`.Table` objects for all current
:class:`.DeferredReflection` subclasses"""
to_map = _DeferredMapperConfig.classes_for_base(cls)
for thingy in to_map:
cls._sa_decl_prepare(thingy.local_table, engine)
thingy.map()
mapper = thingy.cls.__mapper__
metadata = mapper.class_.metadata
for rel in mapper._props.values():
if (
isinstance(rel, properties.RelationshipProperty)
and rel.secondary is not None
):
if isinstance(rel.secondary, Table):
cls._reflect_table(rel.secondary, engine)
elif isinstance(rel.secondary, _class_resolver):
rel.secondary._resolvers += (
cls._sa_deferred_table_resolver(engine, metadata),
)
@classmethod
def _sa_deferred_table_resolver(cls, engine, metadata):
def _resolve(key):
t1 = Table(key, metadata)
cls._reflect_table(t1, engine)
return t1
return _resolve
@classmethod
def _sa_decl_prepare(cls, local_table, engine):
# autoload Table, which is already
# present in the metadata. This
# will fill in db-loaded columns
# into the existing Table object.
if local_table is not None:
cls._reflect_table(local_table, engine)
@classmethod
def _sa_raise_deferred_config(cls):
raise orm_exc.UnmappedClassError(
cls,
msg="Class %s is a subclass of DeferredReflection. "
"Mappings are not produced until the .prepare() "
"method is called on the class hierarchy."
% orm_exc._safe_cls_name(cls),
)
@classmethod
def _reflect_table(cls, table, engine):
Table(
table.name,
table.metadata,
extend_existing=True,
autoload_replace=False,
autoload=True,
autoload_with=engine,
schema=table.schema,
)
@inspection._inspects(DeclarativeMeta)
def _inspect_decl_meta(cls):
mp = _inspect_mapped_class(cls)
if mp is None:
if _DeferredMapperConfig.has_cls(cls):
_DeferredMapperConfig.raise_unmapped_for_cls(cls)
raise orm_exc.UnmappedClassError(
cls,
msg="Class %s has a deferred mapping on it. It is not yet "
"usable as a mapped class." % orm_exc._safe_cls_name(cls),
)
return mp

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# ext/declarative/base.py
# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Internal implementation for declarative."""
import collections
import weakref
from sqlalchemy.orm import instrumentation
from . import clsregistry
from ... import event
from ... import exc
from ... import util
from ...orm import class_mapper
from ...orm import exc as orm_exc
from ...orm import mapper
from ...orm import mapperlib
from ...orm import synonym
from ...orm.attributes import QueryableAttribute
from ...orm.base import _is_mapped_class
from ...orm.base import InspectionAttr
from ...orm.interfaces import MapperProperty
from ...orm.properties import ColumnProperty
from ...orm.properties import CompositeProperty
from ...schema import Column
from ...schema import Table
from ...sql import expression
from ...util import topological
declared_attr = declarative_props = None
def _declared_mapping_info(cls):
# deferred mapping
if _DeferredMapperConfig.has_cls(cls):
return _DeferredMapperConfig.config_for_cls(cls)
# regular mapping
elif _is_mapped_class(cls):
return class_mapper(cls, configure=False)
else:
return None
def _resolve_for_abstract_or_classical(cls):
if cls is object:
return None
if _get_immediate_cls_attr(cls, "__abstract__", strict=True):
for sup in cls.__bases__:
sup = _resolve_for_abstract_or_classical(sup)
if sup is not None:
return sup
else:
return None
else:
classical = _dive_for_classically_mapped_class(cls)
if classical is not None:
return classical
else:
return cls
def _dive_for_classically_mapped_class(cls):
# support issue #4321
# if we are within a base hierarchy, don't
# search at all for classical mappings
if hasattr(cls, "_decl_class_registry"):
return None
manager = instrumentation.manager_of_class(cls)
if manager is not None:
return cls
else:
for sup in cls.__bases__:
mapper = _dive_for_classically_mapped_class(sup)
if mapper is not None:
return sup
else:
return None
def _get_immediate_cls_attr(cls, attrname, strict=False):
"""return an attribute of the class that is either present directly
on the class, e.g. not on a superclass, or is from a superclass but
this superclass is a non-mapped mixin, that is, not a descendant of
the declarative base and is also not classically mapped.
This is used to detect attributes that indicate something about
a mapped class independently from any mapped classes that it may
inherit from.
"""
if not issubclass(cls, object):
return None
for base in cls.__mro__:
_is_declarative_inherits = hasattr(base, "_decl_class_registry")
_is_classicial_inherits = (
not _is_declarative_inherits
and _dive_for_classically_mapped_class(base) is not None
)
if attrname in base.__dict__ and (
base is cls
or (
(base in cls.__bases__ if strict else True)
and not _is_declarative_inherits
and not _is_classicial_inherits
)
):
return getattr(base, attrname)
else:
return None
def _as_declarative(cls, classname, dict_):
global declared_attr, declarative_props
if declared_attr is None:
from .api import declared_attr
declarative_props = (declared_attr, util.classproperty)
if _get_immediate_cls_attr(cls, "__abstract__", strict=True):
return
_MapperConfig.setup_mapping(cls, classname, dict_)
def _check_declared_props_nocascade(obj, name, cls):
if isinstance(obj, declarative_props):
if getattr(obj, "_cascading", False):
util.warn(
"@declared_attr.cascading is not supported on the %s "
"attribute on class %s. This attribute invokes for "
"subclasses in any case." % (name, cls)
)
return True
else:
return False
class _MapperConfig(object):
@classmethod
def setup_mapping(cls, cls_, classname, dict_):
defer_map = _get_immediate_cls_attr(
cls_, "_sa_decl_prepare_nocascade", strict=True
) or hasattr(cls_, "_sa_decl_prepare")
if defer_map:
cfg_cls = _DeferredMapperConfig
else:
cfg_cls = _MapperConfig
cfg_cls(cls_, classname, dict_)
def __init__(self, cls_, classname, dict_):
self.cls = cls_
# dict_ will be a dictproxy, which we can't write to, and we need to!
self.dict_ = dict(dict_)
self.classname = classname
self.persist_selectable = None
self.properties = util.OrderedDict()
self.declared_columns = set()
self.column_copies = {}
self._setup_declared_events()
# temporary registry. While early 1.0 versions
# set up the ClassManager here, by API contract
# we can't do that until there's a mapper.
self.cls._sa_declared_attr_reg = {}
self._scan_attributes()
mapperlib._CONFIGURE_MUTEX.acquire()
try:
clsregistry.add_class(self.classname, self.cls)
self._extract_mappable_attributes()
self._extract_declared_columns()
self._setup_table()
self._setup_inheritance()
self._early_mapping()
finally:
mapperlib._CONFIGURE_MUTEX.release()
def _early_mapping(self):
self.map()
def _setup_declared_events(self):
if _get_immediate_cls_attr(self.cls, "__declare_last__"):
@event.listens_for(mapper, "after_configured")
def after_configured():
self.cls.__declare_last__()
if _get_immediate_cls_attr(self.cls, "__declare_first__"):
@event.listens_for(mapper, "before_configured")
def before_configured():
self.cls.__declare_first__()
def _scan_attributes(self):
cls = self.cls
dict_ = self.dict_
column_copies = self.column_copies
mapper_args_fn = None
table_args = inherited_table_args = None
tablename = None
for base in cls.__mro__:
class_mapped = (
base is not cls
and _declared_mapping_info(base) is not None
and not _get_immediate_cls_attr(
base, "_sa_decl_prepare_nocascade", strict=True
)
)
if not class_mapped and base is not cls:
self._produce_column_copies(base)
for name, obj in vars(base).items():
if name == "__mapper_args__":
check_decl = _check_declared_props_nocascade(
obj, name, cls
)
if not mapper_args_fn and (not class_mapped or check_decl):
# don't even invoke __mapper_args__ until
# after we've determined everything about the
# mapped table.
# make a copy of it so a class-level dictionary
# is not overwritten when we update column-based
# arguments.
def mapper_args_fn():
return dict(cls.__mapper_args__)
elif name == "__tablename__":
check_decl = _check_declared_props_nocascade(
obj, name, cls
)
if not tablename and (not class_mapped or check_decl):
tablename = cls.__tablename__
elif name == "__table_args__":
check_decl = _check_declared_props_nocascade(
obj, name, cls
)
if not table_args and (not class_mapped or check_decl):
table_args = cls.__table_args__
if not isinstance(
table_args, (tuple, dict, type(None))
):
raise exc.ArgumentError(
"__table_args__ value must be a tuple, "
"dict, or None"
)
if base is not cls:
inherited_table_args = True
elif class_mapped:
if isinstance(obj, declarative_props):
util.warn(
"Regular (i.e. not __special__) "
"attribute '%s.%s' uses @declared_attr, "
"but owning class %s is mapped - "
"not applying to subclass %s."
% (base.__name__, name, base, cls)
)
continue
elif base is not cls:
# we're a mixin, abstract base, or something that is
# acting like that for now.
if isinstance(obj, Column):
# already copied columns to the mapped class.
continue
elif isinstance(obj, MapperProperty):
raise exc.InvalidRequestError(
"Mapper properties (i.e. deferred,"
"column_property(), relationship(), etc.) must "
"be declared as @declared_attr callables "
"on declarative mixin classes."
)
elif isinstance(obj, declarative_props):
oldclassprop = isinstance(obj, util.classproperty)
if not oldclassprop and obj._cascading:
if name in dict_:
# unfortunately, while we can use the user-
# defined attribute here to allow a clean
# override, if there's another
# subclass below then it still tries to use
# this. not sure if there is enough
# information here to add this as a feature
# later on.
util.warn(
"Attribute '%s' on class %s cannot be "
"processed due to "
"@declared_attr.cascading; "
"skipping" % (name, cls)
)
dict_[name] = column_copies[
obj
] = ret = obj.__get__(obj, cls)
setattr(cls, name, ret)
else:
if oldclassprop:
util.warn_deprecated(
"Use of sqlalchemy.util.classproperty on "
"declarative classes is deprecated."
)
# access attribute using normal class access
ret = getattr(cls, name)
# correct for proxies created from hybrid_property
# or similar. note there is no known case that
# produces nested proxies, so we are only
# looking one level deep right now.
if (
isinstance(ret, InspectionAttr)
and ret._is_internal_proxy
and not isinstance(
ret.original_property, MapperProperty
)
):
ret = ret.descriptor
dict_[name] = column_copies[obj] = ret
if (
isinstance(ret, (Column, MapperProperty))
and ret.doc is None
):
ret.doc = obj.__doc__
# here, the attribute is some other kind of property that
# we assume is not part of the declarative mapping.
# however, check for some more common mistakes
else:
self._warn_for_decl_attributes(base, name, obj)
if inherited_table_args and not tablename:
table_args = None
self.table_args = table_args
self.tablename = tablename
self.mapper_args_fn = mapper_args_fn
def _warn_for_decl_attributes(self, cls, key, c):
if isinstance(c, expression.ColumnClause):
util.warn(
"Attribute '%s' on class %s appears to be a non-schema "
"'sqlalchemy.sql.column()' "
"object; this won't be part of the declarative mapping"
% (key, cls)
)
def _produce_column_copies(self, base):
cls = self.cls
dict_ = self.dict_
column_copies = self.column_copies
# copy mixin columns to the mapped class
for name, obj in vars(base).items():
if isinstance(obj, Column):
if getattr(cls, name) is not obj:
# if column has been overridden
# (like by the InstrumentedAttribute of the
# superclass), skip
continue
elif obj.foreign_keys:
raise exc.InvalidRequestError(
"Columns with foreign keys to other columns "
"must be declared as @declared_attr callables "
"on declarative mixin classes. "
)
elif name not in dict_ and not (
"__table__" in dict_
and (obj.name or name) in dict_["__table__"].c
):
column_copies[obj] = copy_ = obj.copy()
copy_._creation_order = obj._creation_order
setattr(cls, name, copy_)
dict_[name] = copy_
def _extract_mappable_attributes(self):
cls = self.cls
dict_ = self.dict_
our_stuff = self.properties
late_mapped = _get_immediate_cls_attr(
cls, "_sa_decl_prepare_nocascade", strict=True
)
for k in list(dict_):
if k in ("__table__", "__tablename__", "__mapper_args__"):
continue
value = dict_[k]
if isinstance(value, declarative_props):
if isinstance(value, declared_attr) and value._cascading:
util.warn(
"Use of @declared_attr.cascading only applies to "
"Declarative 'mixin' and 'abstract' classes. "
"Currently, this flag is ignored on mapped class "
"%s" % self.cls
)
value = getattr(cls, k)
elif (
isinstance(value, QueryableAttribute)
and value.class_ is not cls
and value.key != k
):
# detect a QueryableAttribute that's already mapped being
# assigned elsewhere in userland, turn into a synonym()
value = synonym(value.key)
setattr(cls, k, value)
if (
isinstance(value, tuple)
and len(value) == 1
and isinstance(value[0], (Column, MapperProperty))
):
util.warn(
"Ignoring declarative-like tuple value of attribute "
"'%s': possibly a copy-and-paste error with a comma "
"accidentally placed at the end of the line?" % k
)
continue
elif not isinstance(value, (Column, MapperProperty)):
# using @declared_attr for some object that
# isn't Column/MapperProperty; remove from the dict_
# and place the evaluated value onto the class.
if not k.startswith("__"):
dict_.pop(k)
self._warn_for_decl_attributes(cls, k, value)
if not late_mapped:
setattr(cls, k, value)
continue
# we expect to see the name 'metadata' in some valid cases;
# however at this point we see it's assigned to something trying
# to be mapped, so raise for that.
elif k == "metadata":
raise exc.InvalidRequestError(
"Attribute name 'metadata' is reserved "
"for the MetaData instance when using a "
"declarative base class."
)
prop = clsregistry._deferred_relationship(cls, value)
our_stuff[k] = prop
def _extract_declared_columns(self):
our_stuff = self.properties
# set up attributes in the order they were created
our_stuff.sort(key=lambda key: our_stuff[key]._creation_order)
# extract columns from the class dict
declared_columns = self.declared_columns
name_to_prop_key = collections.defaultdict(set)
for key, c in list(our_stuff.items()):
if isinstance(c, (ColumnProperty, CompositeProperty)):
for col in c.columns:
if isinstance(col, Column) and col.table is None:
_undefer_column_name(key, col)
if not isinstance(c, CompositeProperty):
name_to_prop_key[col.name].add(key)
declared_columns.add(col)
elif isinstance(c, Column):
_undefer_column_name(key, c)
name_to_prop_key[c.name].add(key)
declared_columns.add(c)
# if the column is the same name as the key,
# remove it from the explicit properties dict.
# the normal rules for assigning column-based properties
# will take over, including precedence of columns
# in multi-column ColumnProperties.
if key == c.key:
del our_stuff[key]
for name, keys in name_to_prop_key.items():
if len(keys) > 1:
util.warn(
"On class %r, Column object %r named "
"directly multiple times, "
"only one will be used: %s. "
"Consider using orm.synonym instead"
% (self.classname, name, (", ".join(sorted(keys))))
)
def _setup_table(self):
cls = self.cls
tablename = self.tablename
table_args = self.table_args
dict_ = self.dict_
declared_columns = self.declared_columns
declared_columns = self.declared_columns = sorted(
declared_columns, key=lambda c: c._creation_order
)
table = None
if hasattr(cls, "__table_cls__"):
table_cls = util.unbound_method_to_callable(cls.__table_cls__)
else:
table_cls = Table
if "__table__" not in dict_:
if tablename is not None:
args, table_kw = (), {}
if table_args:
if isinstance(table_args, dict):
table_kw = table_args
elif isinstance(table_args, tuple):
if isinstance(table_args[-1], dict):
args, table_kw = table_args[0:-1], table_args[-1]
else:
args = table_args
autoload = dict_.get("__autoload__")
if autoload:
table_kw["autoload"] = True
cls.__table__ = table = table_cls(
tablename,
cls.metadata,
*(tuple(declared_columns) + tuple(args)),
**table_kw
)
else:
table = cls.__table__
if declared_columns:
for c in declared_columns:
if not table.c.contains_column(c):
raise exc.ArgumentError(
"Can't add additional column %r when "
"specifying __table__" % c.key
)
self.local_table = table
def _setup_inheritance(self):
table = self.local_table
cls = self.cls
table_args = self.table_args
declared_columns = self.declared_columns
# since we search for classical mappings now, search for
# multiple mapped bases as well and raise an error.
inherits = []
for c in cls.__bases__:
c = _resolve_for_abstract_or_classical(c)
if c is None:
continue
if _declared_mapping_info(
c
) is not None and not _get_immediate_cls_attr(
c, "_sa_decl_prepare_nocascade", strict=True
):
inherits.append(c)
if inherits:
if len(inherits) > 1:
raise exc.InvalidRequestError(
"Class %s has multiple mapped bases: %r" % (cls, inherits)
)
self.inherits = inherits[0]
else:
self.inherits = None
if (
table is None
and self.inherits is None
and not _get_immediate_cls_attr(cls, "__no_table__")
):
raise exc.InvalidRequestError(
"Class %r does not have a __table__ or __tablename__ "
"specified and does not inherit from an existing "
"table-mapped class." % cls
)
elif self.inherits:
inherited_mapper = _declared_mapping_info(self.inherits)
inherited_table = inherited_mapper.local_table
inherited_persist_selectable = inherited_mapper.persist_selectable
if table is None:
# single table inheritance.
# ensure no table args
if table_args:
raise exc.ArgumentError(
"Can't place __table_args__ on an inherited class "
"with no table."
)
# add any columns declared here to the inherited table.
for c in declared_columns:
if c.name in inherited_table.c:
if inherited_table.c[c.name] is c:
continue
raise exc.ArgumentError(
"Column '%s' on class %s conflicts with "
"existing column '%s'"
% (c, cls, inherited_table.c[c.name])
)
if c.primary_key:
raise exc.ArgumentError(
"Can't place primary key columns on an inherited "
"class with no table."
)
inherited_table.append_column(c)
if (
inherited_persist_selectable is not None
and inherited_persist_selectable is not inherited_table
):
inherited_persist_selectable._refresh_for_new_column(c)
def _prepare_mapper_arguments(self):
properties = self.properties
if self.mapper_args_fn:
mapper_args = self.mapper_args_fn()
else:
mapper_args = {}
# make sure that column copies are used rather
# than the original columns from any mixins
for k in ("version_id_col", "polymorphic_on"):
if k in mapper_args:
v = mapper_args[k]
mapper_args[k] = self.column_copies.get(v, v)
assert (
"inherits" not in mapper_args
), "Can't specify 'inherits' explicitly with declarative mappings"
if self.inherits:
mapper_args["inherits"] = self.inherits
if self.inherits and not mapper_args.get("concrete", False):
# single or joined inheritance
# exclude any cols on the inherited table which are
# not mapped on the parent class, to avoid
# mapping columns specific to sibling/nephew classes
inherited_mapper = _declared_mapping_info(self.inherits)
inherited_table = inherited_mapper.local_table
if "exclude_properties" not in mapper_args:
mapper_args["exclude_properties"] = exclude_properties = set(
[
c.key
for c in inherited_table.c
if c not in inherited_mapper._columntoproperty
]
).union(inherited_mapper.exclude_properties or ())
exclude_properties.difference_update(
[c.key for c in self.declared_columns]
)
# look through columns in the current mapper that
# are keyed to a propname different than the colname
# (if names were the same, we'd have popped it out above,
# in which case the mapper makes this combination).
# See if the superclass has a similar column property.
# If so, join them together.
for k, col in list(properties.items()):
if not isinstance(col, expression.ColumnElement):
continue
if k in inherited_mapper._props:
p = inherited_mapper._props[k]
if isinstance(p, ColumnProperty):
# note here we place the subclass column
# first. See [ticket:1892] for background.
properties[k] = [col] + p.columns
result_mapper_args = mapper_args.copy()
result_mapper_args["properties"] = properties
self.mapper_args = result_mapper_args
def map(self):
self._prepare_mapper_arguments()
if hasattr(self.cls, "__mapper_cls__"):
mapper_cls = util.unbound_method_to_callable(
self.cls.__mapper_cls__
)
else:
mapper_cls = mapper
self.cls.__mapper__ = mp_ = mapper_cls(
self.cls, self.local_table, **self.mapper_args
)
del self.cls._sa_declared_attr_reg
return mp_
class _DeferredMapperConfig(_MapperConfig):
_configs = util.OrderedDict()
def _early_mapping(self):
pass
@property
def cls(self):
return self._cls()
@cls.setter
def cls(self, class_):
self._cls = weakref.ref(class_, self._remove_config_cls)
self._configs[self._cls] = self
@classmethod
def _remove_config_cls(cls, ref):
cls._configs.pop(ref, None)
@classmethod
def has_cls(cls, class_):
# 2.6 fails on weakref if class_ is an old style class
return isinstance(class_, type) and weakref.ref(class_) in cls._configs
@classmethod
def raise_unmapped_for_cls(cls, class_):
if hasattr(class_, "_sa_raise_deferred_config"):
class_._sa_raise_deferred_config()
raise orm_exc.UnmappedClassError(
class_,
msg="Class %s has a deferred mapping on it. It is not yet "
"usable as a mapped class." % orm_exc._safe_cls_name(class_),
)
@classmethod
def config_for_cls(cls, class_):
return cls._configs[weakref.ref(class_)]
@classmethod
def classes_for_base(cls, base_cls, sort=True):
classes_for_base = [
m
for m, cls_ in [(m, m.cls) for m in cls._configs.values()]
if cls_ is not None and issubclass(cls_, base_cls)
]
if not sort:
return classes_for_base
all_m_by_cls = dict((m.cls, m) for m in classes_for_base)
tuples = []
for m_cls in all_m_by_cls:
tuples.extend(
(all_m_by_cls[base_cls], all_m_by_cls[m_cls])
for base_cls in m_cls.__bases__
if base_cls in all_m_by_cls
)
return list(topological.sort(tuples, classes_for_base))
def map(self):
self._configs.pop(self._cls, None)
return super(_DeferredMapperConfig, self).map()
def _add_attribute(cls, key, value):
"""add an attribute to an existing declarative class.
This runs through the logic to determine MapperProperty,
adds it to the Mapper, adds a column to the mapped Table, etc.
"""
if "__mapper__" in cls.__dict__:
if isinstance(value, Column):
_undefer_column_name(key, value)
cls.__table__.append_column(value)
cls.__mapper__.add_property(key, value)
elif isinstance(value, ColumnProperty):
for col in value.columns:
if isinstance(col, Column) and col.table is None:
_undefer_column_name(key, col)
cls.__table__.append_column(col)
cls.__mapper__.add_property(key, value)
elif isinstance(value, MapperProperty):
cls.__mapper__.add_property(
key, clsregistry._deferred_relationship(cls, value)
)
elif isinstance(value, QueryableAttribute) and value.key != key:
# detect a QueryableAttribute that's already mapped being
# assigned elsewhere in userland, turn into a synonym()
value = synonym(value.key)
cls.__mapper__.add_property(
key, clsregistry._deferred_relationship(cls, value)
)
else:
type.__setattr__(cls, key, value)
cls.__mapper__._expire_memoizations()
else:
type.__setattr__(cls, key, value)
def _del_attribute(cls, key):
if (
"__mapper__" in cls.__dict__
and key in cls.__dict__
and not cls.__mapper__._dispose_called
):
value = cls.__dict__[key]
if isinstance(
value, (Column, ColumnProperty, MapperProperty, QueryableAttribute)
):
raise NotImplementedError(
"Can't un-map individual mapped attributes on a mapped class."
)
else:
type.__delattr__(cls, key)
cls.__mapper__._expire_memoizations()
else:
type.__delattr__(cls, key)
def _declarative_constructor(self, **kwargs):
"""A simple constructor that allows initialization from kwargs.
Sets attributes on the constructed instance using the names and
values in ``kwargs``.
Only keys that are present as
attributes of the instance's class are allowed. These could be,
for example, any mapped columns or relationships.
"""
cls_ = type(self)
for k in kwargs:
if not hasattr(cls_, k):
raise TypeError(
"%r is an invalid keyword argument for %s" % (k, cls_.__name__)
)
setattr(self, k, kwargs[k])
_declarative_constructor.__name__ = "__init__"
def _undefer_column_name(key, column):
if column.key is None:
column.key = key
if column.name is None:
column.name = key

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# ext/declarative/clsregistry.py
# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Routines to handle the string class registry used by declarative.
This system allows specification of classes and expressions used in
:func:`.relationship` using strings.
"""
import weakref
from ... import exc
from ... import inspection
from ... import util
from ...orm import class_mapper
from ...orm import interfaces
from ...orm.properties import ColumnProperty
from ...orm.properties import RelationshipProperty
from ...orm.properties import SynonymProperty
from ...schema import _get_table_key
# strong references to registries which we place in
# the _decl_class_registry, which is usually weak referencing.
# the internal registries here link to classes with weakrefs and remove
# themselves when all references to contained classes are removed.
_registries = set()
def add_class(classname, cls):
"""Add a class to the _decl_class_registry associated with the
given declarative class.
"""
if classname in cls._decl_class_registry:
# class already exists.
existing = cls._decl_class_registry[classname]
if not isinstance(existing, _MultipleClassMarker):
existing = cls._decl_class_registry[
classname
] = _MultipleClassMarker([cls, existing])
else:
cls._decl_class_registry[classname] = cls
try:
root_module = cls._decl_class_registry["_sa_module_registry"]
except KeyError:
cls._decl_class_registry[
"_sa_module_registry"
] = root_module = _ModuleMarker("_sa_module_registry", None)
tokens = cls.__module__.split(".")
# build up a tree like this:
# modulename: myapp.snacks.nuts
#
# myapp->snack->nuts->(classes)
# snack->nuts->(classes)
# nuts->(classes)
#
# this allows partial token paths to be used.
while tokens:
token = tokens.pop(0)
module = root_module.get_module(token)
for token in tokens:
module = module.get_module(token)
module.add_class(classname, cls)
class _MultipleClassMarker(object):
"""refers to multiple classes of the same name
within _decl_class_registry.
"""
__slots__ = "on_remove", "contents", "__weakref__"
def __init__(self, classes, on_remove=None):
self.on_remove = on_remove
self.contents = set(
[weakref.ref(item, self._remove_item) for item in classes]
)
_registries.add(self)
def __iter__(self):
return (ref() for ref in self.contents)
def attempt_get(self, path, key):
if len(self.contents) > 1:
raise exc.InvalidRequestError(
'Multiple classes found for path "%s" '
"in the registry of this declarative "
"base. Please use a fully module-qualified path."
% (".".join(path + [key]))
)
else:
ref = list(self.contents)[0]
cls = ref()
if cls is None:
raise NameError(key)
return cls
def _remove_item(self, ref):
self.contents.remove(ref)
if not self.contents:
_registries.discard(self)
if self.on_remove:
self.on_remove()
def add_item(self, item):
# protect against class registration race condition against
# asynchronous garbage collection calling _remove_item,
# [ticket:3208]
modules = set(
[
cls.__module__
for cls in [ref() for ref in self.contents]
if cls is not None
]
)
if item.__module__ in modules:
util.warn(
"This declarative base already contains a class with the "
"same class name and module name as %s.%s, and will "
"be replaced in the string-lookup table."
% (item.__module__, item.__name__)
)
self.contents.add(weakref.ref(item, self._remove_item))
class _ModuleMarker(object):
""""refers to a module name within
_decl_class_registry.
"""
__slots__ = "parent", "name", "contents", "mod_ns", "path", "__weakref__"
def __init__(self, name, parent):
self.parent = parent
self.name = name
self.contents = {}
self.mod_ns = _ModNS(self)
if self.parent:
self.path = self.parent.path + [self.name]
else:
self.path = []
_registries.add(self)
def __contains__(self, name):
return name in self.contents
def __getitem__(self, name):
return self.contents[name]
def _remove_item(self, name):
self.contents.pop(name, None)
if not self.contents and self.parent is not None:
self.parent._remove_item(self.name)
_registries.discard(self)
def resolve_attr(self, key):
return getattr(self.mod_ns, key)
def get_module(self, name):
if name not in self.contents:
marker = _ModuleMarker(name, self)
self.contents[name] = marker
else:
marker = self.contents[name]
return marker
def add_class(self, name, cls):
if name in self.contents:
existing = self.contents[name]
existing.add_item(cls)
else:
existing = self.contents[name] = _MultipleClassMarker(
[cls], on_remove=lambda: self._remove_item(name)
)
class _ModNS(object):
__slots__ = ("__parent",)
def __init__(self, parent):
self.__parent = parent
def __getattr__(self, key):
try:
value = self.__parent.contents[key]
except KeyError:
pass
else:
if value is not None:
if isinstance(value, _ModuleMarker):
return value.mod_ns
else:
assert isinstance(value, _MultipleClassMarker)
return value.attempt_get(self.__parent.path, key)
raise AttributeError(
"Module %r has no mapped classes "
"registered under the name %r" % (self.__parent.name, key)
)
class _GetColumns(object):
__slots__ = ("cls",)
def __init__(self, cls):
self.cls = cls
def __getattr__(self, key):
mp = class_mapper(self.cls, configure=False)
if mp:
if key not in mp.all_orm_descriptors:
raise exc.InvalidRequestError(
"Class %r does not have a mapped column named %r"
% (self.cls, key)
)
desc = mp.all_orm_descriptors[key]
if desc.extension_type is interfaces.NOT_EXTENSION:
prop = desc.property
if isinstance(prop, SynonymProperty):
key = prop.name
elif not isinstance(prop, ColumnProperty):
raise exc.InvalidRequestError(
"Property %r is not an instance of"
" ColumnProperty (i.e. does not correspond"
" directly to a Column)." % key
)
return getattr(self.cls, key)
inspection._inspects(_GetColumns)(
lambda target: inspection.inspect(target.cls)
)
class _GetTable(object):
__slots__ = "key", "metadata"
def __init__(self, key, metadata):
self.key = key
self.metadata = metadata
def __getattr__(self, key):
return self.metadata.tables[_get_table_key(key, self.key)]
def _determine_container(key, value):
if isinstance(value, _MultipleClassMarker):
value = value.attempt_get([], key)
return _GetColumns(value)
class _class_resolver(object):
def __init__(self, cls, prop, fallback, arg):
self.cls = cls
self.prop = prop
self.arg = self._declarative_arg = arg
self.fallback = fallback
self._dict = util.PopulateDict(self._access_cls)
self._resolvers = ()
def _access_cls(self, key):
cls = self.cls
if key in cls._decl_class_registry:
return _determine_container(key, cls._decl_class_registry[key])
elif key in cls.metadata.tables:
return cls.metadata.tables[key]
elif key in cls.metadata._schemas:
return _GetTable(key, cls.metadata)
elif (
"_sa_module_registry" in cls._decl_class_registry
and key in cls._decl_class_registry["_sa_module_registry"]
):
registry = cls._decl_class_registry["_sa_module_registry"]
return registry.resolve_attr(key)
elif self._resolvers:
for resolv in self._resolvers:
value = resolv(key)
if value is not None:
return value
return self.fallback[key]
def __call__(self):
try:
x = eval(self.arg, globals(), self._dict)
if isinstance(x, _GetColumns):
return x.cls
else:
return x
except NameError as n:
raise exc.InvalidRequestError(
"When initializing mapper %s, expression %r failed to "
"locate a name (%r). If this is a class name, consider "
"adding this relationship() to the %r class after "
"both dependent classes have been defined."
% (self.prop.parent, self.arg, n.args[0], self.cls)
)
def _resolver(cls, prop):
import sqlalchemy
from sqlalchemy.orm import foreign, remote
fallback = sqlalchemy.__dict__.copy()
fallback.update({"foreign": foreign, "remote": remote})
def resolve_arg(arg):
return _class_resolver(cls, prop, fallback, arg)
return resolve_arg
def _deferred_relationship(cls, prop):
if isinstance(prop, RelationshipProperty):
resolve_arg = _resolver(cls, prop)
for attr in (
"argument",
"order_by",
"primaryjoin",
"secondaryjoin",
"secondary",
"_user_defined_foreign_keys",
"remote_side",
):
v = getattr(prop, attr)
if isinstance(v, util.string_types):
setattr(prop, attr, resolve_arg(v))
if prop.backref and isinstance(prop.backref, tuple):
key, kwargs = prop.backref
for attr in (
"primaryjoin",
"secondaryjoin",
"secondary",
"foreign_keys",
"remote_side",
"order_by",
):
if attr in kwargs and isinstance(
kwargs[attr], util.string_types
):
kwargs[attr] = resolve_arg(kwargs[attr])
return prop